No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Evaluation of methods for the identification of Salmonella enterica serotype Typhimurium DT104 from poultry environmental samples
Abstract
An increase in the prevalence of Salmonella enterica serotype Typhimurium DT104 has been reported worldwide. This study examined the prevalence of this microorganism in poultry environmental samples from commercial layer flocks and pullet environments as well as the sensitivity and specificity of a PCR-based method, and multiple antibiotic resistance profile of Salmonella serogroup B isolates in relation to the serotype and phagetype reference method for the identification of Salmonella Typhimurium DT104. A total of 435 Salmonella isolates were obtained from poultry house environmental samples tested during a 20-month period representing a prevalence of 5.5%. Of these, 313 (72%) isolates were identified as Salmonella serogroup B isolates. These isolates were tested by a PCR-based assay, and for resistance to five antibiotics: ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline (ACSSuT) for the rapid identification of Salmonella Typhimurium DT104. Upon comparing the antibiotic resistance and PCR results with serotype and phage type data, the sensitivity and specificity for the identification of Salmonella Typhimurium DT104 of both methods were found to be 100%, and 99.6%, respectively. Both methods can be completed within 24 h after obtaining an isolate, while serotyping and phagetyping required more than 5 days to complete.
... This requires a collective effort by public health authorities. Furthermore, as most foodborne diseases are due to mishandling of foods in ways we know we should avoid (e. g., improper cooling, inadequate heating/reheating, and poor personal hygiene), education of food handlers and consumers about the importance of food hygiene may improve safety and so prevent many illnesses (Leon-Velarde et al. 2004;Yan et al. 2005;Sofos 2008). ...
... Such techniques are rapid, sensitive, and specific, which makes them very useful tools to improve the diagnosis and to understand the mechanisms implicated in pathogenicity, resistance, and survival of the new strains described, and so to know how to prevent or inactivate them. Among other identification methods, immunological techniques and antimicrobial resistance profiles have to be considered (Leon-Velarde et al. 2004). ...
Many foodborne diseases are associated with consumption of meat and poultry. Some pathogens were not previously known (new
pathogens), others have newly arisen as foodborne (emerging pathogens), and others have become more potent or associated with
other products (evolving pathogens). Many of these pathogens may cause severe illness, besides gastroenteritis. Campylobacter jejuni is a leading cause of food-associated bacterial illness; Campylobacter jejuni O:19 and other serotypes are common etiological agents of Guillain–Barré syndrome, a neuropathy due to autoimmune response.
Salmonella Typhimurium DT104 and other serotypes have been found to be multi-drug resistant; salmonellosis may lead to chronic reactive
arthritis. Many outbreaks of enterohemorrhagic Escherichia coli have been associated with consumption of undercooked contaminated ground beef; complication may occur (e.g., hemolytic uremic
syndrome and thrombotic thrombocytopenic purpura). Listeria monocytogenes is ubiquitous; listeriosis is of major public health concern because of the severity and non-enteric nature of the disease
(meningitis or meningoencephalitis, septicemia, and abortion) and its ability to multiply at refrigeration temperature. Arcobacter butzleri is a potential foodborne pathogen, and has been isolated from raw poultry, meat, and meat products; but its role in causing
human illness is not fully understood. Mycobacterium avium subsp. paratuberculosis can be transmitted by ingestion of raw and processed meats; the organism may contribute to Crohn’s disease, a chronic intestinal
enteritis. Beef, pork, lamb, and/or poultry have been reported as sources of infection for the abovementioned organisms but
have not been generally associated with disease outbreaks of some of the pathogens.
... The farm-based surveillance data from this study identified Salmonella enterica serovars Kiambu, Infantis, Kentucky, Livingstone, and Mbandaka/Montevideo as the most frequently detected serovars via CRISPR method (Table 6), reflecting a significant change in predominant serovars as reported in previous studies. Salmonella enterica serovars Heidelberg, Typhimurium, Thompson, Schwarzengrund, and Agona were the most commonly isolated serovars from pullet layer and pullet barns in Ontario between 2002 and 2003 (37). Salmonella Heidelberg (50.7%) was again the most prevalent serovar detected between 2009 and 2010, followed by Thompson, Schwarzengrund, Agona, and Kentucky (38). ...
Accurate detection of all Salmonella serovars present in a sample is important in surveillance programs. Current detection protocols are limited to detection of a predominant serovar, missing identification of less abundant serovars in a sample. An alternative method, called CRISPR-SeroSeq, serotyping by sequencing of amplified CRISPR spacers, was employed to detect multiple serovars in a sample without the need of culture isolation. The CRISPR-SeroSeq method successfully detected 34 most frequently reported Salmonella serovars in pure cultures and target serovars at 104 CFU/mL in 27 Salmonella-negative environmental enrichment samples post-spiked with one of 15 different serovars, plus 2 additional serovars at 1 log CFU/mL higher abundance. When the method was applied to 442 naturally contaminated environmental samples collected from 192 poultry farms, 25 different serovars were detected from 430 of the samples. In 73.1% of the samples, 2 to 7 serovars were detected, with Salmonella Kiambu (55.7%), Salmonella Infantis (48.4%), Salmonella Kentucky (27.1%), Salmonella Livingstone (26.6%), and Salmonella Mbandaka/Montevideo (23.4%) being the most prevalent on the farms. Single isolates from 384 samples were also analyzed using a traditional serotyping method, and the same serovar identified by culture was detected by CRISPR-SeroSeq in 96.1% (369/384) of samples, with the former missing detection of additional and sometimes critical serovars. The surveillance data obtained via CRISPR-SeroSeq revealed a significant emergence of Salmonella Kiambu and Salmonella Rissen on poultry farms in Ontario. The results highlight the effectiveness of the CRISPR-SeroSeq approach in detecting multiple Salmonella serovars in poultry environmental samples under applied conditions, providing updated surveillance information on Salmonella serovars on poultry farms in Ontario. IMPORTANCE The CRISPR-SeroSeq method represents an alternative molecular tool to the traditional culture-based serotyping method that can detect multiple Salmonella serovars in a sample and provide rapid serovar results without the need of selective enrichment and culture isolation. The evaluation results can facilitate implementation of the method in routine Salmonella surveillance on poultry farms and in outbreak investigations. The application of the method can increase the accuracy of current serovar prevalence information. The results highlight the effectiveness of the validated method and the need for monitoring Salmonella serovars in poultry environments to improve current surveillance programs. The updated surveillance data provide timely information on emergence of different Salmonella serovars on poultry farms in Ontario and support on-farm risk assessment and risk management of Salmonella.
... The antibiotic sensitivity patterns we found were similar to results obtained by Leon-Velarde et al. [15], essentially consisting of resistance to ampicillin, chloramphenicol, trimethoprim/sulfamethoxazole and tetracycline, the profile of S. Typhimurium DT104. However, due to the absence of facilities in our laboratory for phage typing or PCR, we are unable to investigate these results further. ...
Introduction: Salmonellosis is one of the major foodborne diseases known to be closely related to the consumption of contaminated eggs, infected poultry, and poultry products. Control and survey of the poultry chain are the key elements and the most critical steps in the prevention of human transmission of Salmonella. Methodology: This study was carried out in East Algeria on 150 eggs meant for consumption collected from mini-markets and immediately tested for Salmonella using standard methods (ISO AFNOR 6579 modified in 2002). Briefly, the shell surfaces were carefully wiped using sterile appropriated tissues while the white and yellow yolks were separated. All 10 samples were pooled together and a total of 45 samples were carefully analyzed. Results: A contamination rate of 4.4% was found, and two strains of Salmonella bradford were isolated from white and yellow yolks. The results showed that XLT4 was the best medium for Salmonella isolation from yolks. Screening for other Salmonella in parental chickens using an enzyme-linked immunosorbent assay (ELISA) test revealed seropositive cases of Salmonella enteritidis at the top of the poultry production pyramid. Conclusions: Occurrence of Salmonella in yolks and seropositive results for S. in parental chickens is a serious and potential danger to public health. Radical and preventive measures must be taken at the critical points to control and to avoid human transmission. These measures must be installed at all levels of egg production through the application of appropriate and strict regulations, and use of good hygienic practices in transport, storage, and food preparation.
... The antibiotic sensitivity patterns we found were similar to results obtained by Leon-Velarde et al. [15], essentially consisting of resistance to ampicillin, chloramphenicol, trimethoprim/sulfamethoxazole and tetracycline, the profile of S. Typhimurium DT104. However, due to the absence of facilities in our laboratory for phage typing or PCR, we are unable to investigate these results further. ...
Background: Avian salmonellosis affects the poultry industry in underdeveloped and in developed countries. The aim of this study was to identify the most common Salmonella serovars in broilers and laying breeding reproducers in Eastern Algeria according to the ISO 6579 method. Methodology: A total of 294 samples were obtained from two flocks of 10,000 broilers and laying breeding reproducers. Samples included livers and spleens, drag swabs of bottom boxes of young chickens, cloacal swabs, and faecal samples of chickens. Additional samples were also taken from water, feed and dusty surfaces. Results and conclusions: Only the cloacal swabs, poultry faeces and samples from dusty surfaces were positive for Salmonella Typhimurium and Salmonella Livingstone with a detection rate of 12% and 1.6% respectively. The results showed evidence of legislative failure regarding biosafety within the poultry industry in the area of Batna, Eastern Algeria.
... In addition, these tests require 5-11 days for confirmation of the results (ISO, 2002;FDA, 2007). Real-time polymerase chain reaction (PCR), on the other hand, is one alternative method for a rapid, reliable, feasible, highly specific, and sensitive detection of Salmonella from foods (Anonymous, 2003a;Croci et al., 2004;Ellingson et al., 2004;Leon-Velarde et al., 2004;Perelle et al., 2004;Hein et al., 2006;Malorny et al., 2007;Badosa et al., 2009). Among specific real-time PCR systems, the LightCycler PCR (LC PCR), a capillary air-thermal cycler, has a short detection time of Salmonella DNA from various foods over other real-time PCR systems (Eyigor et al., 2002;Eyigor and Carli, 2003;Jothikumar et al., 2003;Cheung et al., 2004;Wang et al., 2004;Mercanoglu and Griffiths, 2005;Catarame, 2006). ...
Prevalence of Salmonella in slaughter sheep and cattle was determined by International Organization for Standardization Method 6579 (ISO) and Vitek Immunodiagnostic Assay System UP Salmonella Phage Technology (VIDAS UP Salmonella SPT—VIDAS UP). A total of 400 healthy slaughter sheep (n = 200) and cattle (n = 200) carcass (C), fecal content (FC), mesenteric lymph node (MLN), liver (L), kidney (K), spleen (S) and gall bladder (GB) were randomly sampled and analysed. ISO and VIDAS UP results indicated 13 (3.25%) and 17 (4.25%) of 400 animals carried Salmonella, respectively, regardless of sample type. There was no isolation from L, S, GB, while 2 C (0.5%), 6 FC (1.5%), 7 MLN (1.75%), 3 K (0.75%) were contaminated with Salmonella. S. Typhimurium (27.8%), S. Enteritidis (22.2%), S. Newport (22.2%) were the three dominant serovars, followed by S. Kentucky (11.1%), S. Umbilo (5.6%), S. Corvallis (5.6%), and S. Albany (5.6%). Overall prevalence in 2800 samples was 0.46% by ISO and 0.61% by VIDAS UP. High relative trueness (RT: 99.79%) of VIDAS UP with a substantial agreement to ISO (κ value: 0.80) indicated its efficiency to accompany ISO to monitor Salmonella in slaughter animals. As the first report to evaluate ISO and VIDAS UP in detecting Salmonella from slaughter sheep and cattle, this current prevalence signifies a risk for public health in red-meat and related products in Turkey.
... Using the sampling method proposed by Leon and Hassan [42,43], 251 samples of chicken feces were collected from 12 large-scale chicken farms in Zhejiang province in 2017. ...
Background
The emergence of carbapenem-resistant Enterobacteriaceae strains has posed a severe threat to public health in recent years. The mobile elements carrying the New Delhi metallo-β-lactqtamase (NDM) gene have been regarded as the major mechanism leading to the rapid increase of carbapenem-resistant Enterobacteriaceae strains isolated from clinics and animals.
Results
We describe an NDM-5-producing Escherichia coli strain, ECCRA-119 (sequence type 156 [ST156]), isolated from a poultry farm in Zhejiang, China. ECCRA-119 is a multidrug-resistant (MDR) isolate that exhibited resistance to 27 antimicrobial compounds, including imipenem and meropenem, as detected by antimicrobial susceptibility testing (AST). The complete genome sequence of the ECCRA-119 isolate was also obtained using the PacBio RS II platform. Eleven acquired resistance genes were identified in the chromosome; four were detected in plasmid pTB201, while six were detected in plasmid pTB202. Importantly, the carbapenem-resistant gene blaNDM-5 was detected in the IncX3 plasmid pTB203. In addition, seven virulence genes and one metal-resistance gene were also detected. The results of conjugation experiments and the transfer regions identification indicated that the blaNDM-5-harboring plasmid pTB203 could be transferred between E. coli strains.
Conclusions
The results reflected the severe bacterial resistance in a poultry farm in Zhejiang province and increased our understanding of the presence and transmission of the blaNDM-5 gene.
Electronic supplementary material
The online version of this article (10.1186/s12866-019-1454-2) contains supplementary material, which is available to authorized users.
... Indeed, the latter was resistant to five antibiotics (ampicillin, chloramphenicol, streptomycin, sulphonamide and tetracycline). This ACSuST resistance profile is a frequently observed pattern in S. Typhimurium DT104 (Leon-Velarde et al. 2004). Such multiple drug resistance (MDR) is considered a greater public health significance, in that, although the relative incidence of confirmed infections with S. Typhimurium has remained constant at approximately 30% of all confirmed salmonellosis cases in Ireland over the last 5 years (Anon 2000b(Anon , 2003b(Anon , 2004, the proportion of salmonellosis caused by MDR forms of S. Typhimurium, particularly DT104 isolates, has steadily increased (Anon 2004), which currently represents an increasing threat to public health (Anon 2004). ...
... For example, common food-borne pathogens such as Salmonella and S. aureus, which have been reported as causes of food-borne disease, are not typical environmental contaminants, but usually contaminate the food during processing or food-service operations (Kasai et al., 2010;Vollaard et al., 2004). Mishandling such as improper cooling, inadequate fish handling, and cross contamination to other food may occur when the fish is prepared and cleaned for consumption (Beatty et al., 2009;Leon-Velarde et al., 2004;Mor-Mur and Yuste, 2010;Sofos, 2008;Yan et al., 2005). Moreover, cleaning and filleting decrease the fish's shelf-life. ...
... Illnesses caused by foodborne pathogens such as Listeria monocytogenes, Salmonella Typhimurium and Escherichia coli have a wide economic and public health impact worldwide (Hall 1997). For example, Salmonella Typhimurium is responsible for 40-70% of cases of human salmonellosis with the common symptoms such as diarrhea, fever, head-ache, abdominal pain, vomiting and less frequently, blood in the stool (Leon-Velarde et al. 2004). ...
The present study was conducted to evaluate the antioxidant and antibacterial activities of water extracts of sumac (Rhus coriaria), barberry (Berberis vulgaris), black pepper (Piper nigrum), red pepper (Capsicum annuum), fennel (Foeniculum vulgare), laurel (Laurus nobilis), cardamom (Elettaria cardamomum), turmeric (Curcuma longa), white mustard (Sinapis alba) and nutmeg (Myristica fragrans). The antioxidant activity of extracts was tested using 2,2-diphenyl-1-picrylhydrazyl and reducing power tests. The antibacterial activity of extracts was determined by agar well diffusion and resazurin microtiter-plate assays. Sumac, laurel and barberry extracts showed the highest antioxidant activity, respectively. Meanwhile, the highest concentration of total phenolic was obtained in the extracts of laurel and sumac. The results of antibacterial tests revealed that the extracts of sumac and barberry had the strongest antibacterial activity against tested bacteria.Practical ApplicationsThere is an increasing interest in using plant extracts by the food industry as natural preservatives. Lipid oxidation and microbial growth in food can be controlled by the use of plant extracts. This study showed that the water extracts of sumac, laurel and barberry had the strongest antioxidant activity while the sumac and barberry extracts exhibited the highest antibacterial activity against four foodborne pathogenic bacteria. Therefore, the water extracts of sumac, laurel and barberry can be used as effective preservatives in food systems.
... Salmonella Derby was the most common serotype detected in plant A, whereas in Plant B, the serotype isolated most prevalently was Salmonella Typhimurium. This study is somewhat in agreement with several reports that demonstrated that the most common serotypes isolated from poultry were Salmonella Enteritidis, Salmonella Hadar, and Salmonella Typhimurium (Uyttendaele et al., 1998;Leon-Velarde et al., 2004). Most recently, the CDC published their annual summary on Salmonella recovery from human and nonhuman sources. ...
Salmonella isolates were collected from 2 commercial turkey processing plants (A and B) located in different US geographical locations. Isolates recovered at different stages of processing were subjected to 2 genotype techniques [PAGE and denatured gradient gel electrophoresis (DGGE)] to determine their usefulness for Salmonella serotyping. Primers used for PCR amplification were to a highly conserved spacer region located between the 16S and 23S rDNA genes. Sampling sites at plant A were 1) postscald, 2) pre-inside-outside bird wash, 3) post-IOBW, and 4) postchill with 30, 44, 36, and 12 Salmonella isolates recovered, respectively. Plant B had an additional site and these locations were 1) prescald, 2) postscald, 3) pre-inside-outside bird wash, 4) post-IOBW, and 5) postchill with 16, 54, 24, 35, and 24 Salmonella isolates recovered, respectively. In plant A, 4 different Salmonella serotypes were identified: Derby, Hadar, Montevideo, and Senftenberg. In plant B, 10 serotypes were identified: Agona, Anatum, Brandenburg, Derby, Hadar, Meleagridis, Montevideo, Reading, Senftenberg, and Typhimurium. Salmonella Derby was predominant in plant A (83%), whereas Salmonella Typhimurium was the most common serotype recovered in plant B (39%). Genotype analyses of the Salmonella serotypes were expressed in dendrograms with comparisons interpreted as percentage similarity coefficients. Both PAGE and DGGE were able to distinguish serotype band patterns. However, DGGE was more discriminating than PAGE. Isolates of the same serotypes were grouped together on the dendrogram of band patterns generated by DGGE. In contrast, PAGE failed to group all like serotypes together on the corresponding dendrogram. The results of the study suggest that genotyping techniques can be very useful in discriminating Salmonella serotypes collected from the processing plant environment of commercial poultry production. These molecular techniques may offer more cost-effective means to identify Salmonella serotypes from large numbers of isolates and with more immediate results than those currently achieved with conventional typing techniques.
... This can lead to contamination of the poultry carcasses from the feathers and feet of birds and therefore litter is an excellent indicator of poultry contamination by Salmonella [5]. The antibiotic sensitivity patterns we found were similar to results obtained by Leon-Velarde et al. [15], essentially consisting of resistance to ampicillin, chloramphenicol, trimethoprim/sulfamethoxazole and tetracycline, the profile of S. Typhimurium DT104. However, due to the absence of facilities in our laboratory for phage typing or PCR, we are unable to investigate these results further. ...
Avian salmonellosis affects the poultry industry in underdeveloped and in developed countries. The aim of this study was to identify the most common Salmonella serovars in broilers and laying breeding reproducers in Eastern Algeria according to the ISO 6579 method.
A total of 294 samples were obtained from two flocks of 10,000 broilers and laying breeding reproducers. Samples included livers and spleens, drag swabs of bottom boxes of young chickens, cloacal swabs, and faecal samples of chickens. Additional samples were also taken from water, feed and dusty surfaces.
Only the cloacal swabs, poultry faeces and samples from dusty surfaces were positive for Salmonella Typhimurium and Salmonella Livingstone with a detection rate of 12% and 1.6% respectively. The results showed evidence of legislative failure regarding biosafety within the poultry industry in the area of Batna, Eastern Algeria.
... This procedure is time-consuming, laborious and costly. Rapid and inexpensive PCR assays for the detection of Salmonella at the genus level have been developed (Rahn et al., 1992), but the number of assays to determine the Salmonella serotype is limited and includes those to detect serotypes Enteriditis (Lampel et al., 1996), Gallinarum (Shah et al., 2005), Typhi (Farrell et al., 2005; Kumar et al., 2006) and Typhimurium (Leon-Velarde et al., 2004). To date, there is no serotype-specific PCR assay for the detection of S. Brandenburg. ...
Currently, Salmonella enterica serovar Brandenburg is identified serologically on the basis of two surface antigens, somatic (O) polysaccharide and flagellar (H) proteins. This procedure is time-consuming and requires expensive typing reagents. To overcome these problems, a PCR method was developed and validated for the identification of S. Brandenburg. Portions of the invA, rfbJ(B), fliC and fljB genes were targeted for amplification using four pairs of oligonucleotide primers. To validate the assay, genomic DNA from an array of 72 Salmonella strains representing 28 serotypes and 5 non-Salmonella strains from 4 different genera was subjected to PCR. The four targeted genes were correctly amplified only from S. Brandenburg. These results indicate that this PCR assay is a simple, rapid, reliable and reproducible method for the identification of S. Brandenburg that will aid in surveillance, prevention and control of this pathogen.
... This price was considered ''acceptable'' by the poultry sector, particularly when the tests were applied in breeder flock screenings. Throughout this study, we used both bacteriology and PCR for the detection of Salmonella in intestinal samples, cloacal swabs, drag swabs, litter samples, and chick dust samples, in parallel to previous detection reports from faecal (Cohen et al ., 1994;Makino et al ., 1999), environmental (Tuchili et al ., 1996;Soumet et al ., 1999;Leon-Velarde et al ., 2004) samples by both methods, and also from cloacal swabs (Bichler et al ., 1996;Allen-Vercoe & Woodward, 1999) by bacteriology. In our study, regardless of the method used, we obtained consistently low Salmonella detection rates in the first year, followed by no detection in the following years from cloacal swabs, whereas we were getting satisfactory results from other sample types, particularly from intestinal samples. ...
From years 2000 to 2003, Salmonella was investigated from a total of 1785 samples comprised of chicken intestinal samples, cloacal swabs, drag swabs, litter samples and chick dust samples collected from 191 poultry breeding flocks belonging to 15 different chicken breeding stock companies in the Marmara region, Turkey by a SYBR green-based real-time polymerase chain reaction (SGBRT-PCR), by a probe-specific real-time polymerase chain reaction (PSRT-PCR) and by standardized bacteriology as described in the manual of National Poultry Improvement Plan and Auxillary Provisions, United States Department of Agriculture. Between January 2000 and July 2001, Salmonella was detected at the rates of 5.87% and 4.10% out of a total of 1242 samples by SGBRT-PCR and bacteriology, respectively. From July 2001 until December 2003, Salmonella was found at rates of 11.42% and 5.52% from a total of 543 samples by PSRT-PCR and bacteriology, respectively. The dominant Salmonella serovar was determined as Salmonella enterica subsp. enterica Serovar Enteritidis (S. Enteritidis), while serogroup C1 and C2 in 2001 and serogroup E1 in 2002 were isolated as additional serovars. As a conclusion, S. Enteritidis seems to be the major problem in poultry breeding flocks in Turkey, and both of the real-time polymerase chain reaction methods were found more sensitive than standard bacteriology for the detection of Salmonella from poultry samples.
... Indeed, the latter was resistant to five antibiotics (ampicillin, chloramphenicol, streptomycin, sulphonamide and tetracycline). This ACSuST resistance profile is a frequently observed pattern in S. Typhimurium DT104 (Leon-Velarde et al. 2004). Such multiple drug resistance (MDR) is considered a greater public health significance, in that, although the relative incidence of confirmed infections with S. Typhimurium has remained constant at approximately 30% of all confirmed salmonellosis cases in Ireland over the last 5 years (Anon 2000b(Anon , 2003b(Anon , 2004, the proportion of salmonellosis caused by MDR forms of S. Typhimurium, particularly DT104 isolates, has steadily increased (Anon 2004), which currently represents an increasing threat to public health (Anon 2004). ...
The aims of this research were (1) to determine the occurrence of Salmonella in Irish restaurant kitchens and (2) to investigate the serovar, genotype, antibiotic resistance profile and survival/growth profile of the Salmonella under catering chilled storage and temperature abuse conditions.
Five sites/tools in each of 200 randomly selected restaurant kitchens were examined for the presence of presumptive Salmonella spp. by enrichment. Serotyping, antibiotic resistance studies and genotyping were performed using the Kauffmann-White, CLSI and PulseNet methods, respectively. Survival/growth was investigated in milk, meat and vegetable products.
Presumptive isolates from 15 of the 200 restaurant kitchens were recovered and confirmed as Salmonella positive. Seven different serovars showing a variety of antibiotic resistance profiles were detected. PFGE profiles suggested that isolates from geographically adjacent restaurants were related. Salmonella survived in foods stored at typical catering refrigeration temperatures and increased by approximately 0.8 log(10) CFU ml(-1) per day in food products stored under conditions of thermal abuse (20 degrees C).
Inadequate hygiene has resulted in contamination of restaurant kitchens with Salmonella, which may persist/multiply in cross-contaminated foods.
This study highlights the need for greater hygiene in restaurant kitchens coupled with rapid chilling of food not for immediate consumption and reheating before subsequent serving.
To evaluate the hygienic status during preparation of food in fixed and floating hotels from Kitchen area in Luxor, Egypt; one hundred samples were collected; 20 from each raw beef, chicken meat, surface, hand and knife swabs (10 from each, fixed and floating). The meat samples were examined for the Aerobic plate count (APC), Coliforms count (CC) and Coagulase Positive Staphylococci (CPS). As the results indicated that the count varies from satisfactory to unsatisfactory according to the parameter mentioned in Egyptian standards of frozen meat (ES 1522/2005) and (Egyptian standards of frozen poultry) ES 1090/2005, also, the meat samples were examined for the important food borne pathogens (E.coli, Salmonella spp. and other enteric bacteria). The results indicated higher percentage in beef than poultry for E.coli isolation 20% (4/20) and 15% (3/20), respectively; its serotypes are O 26 : H 11 , O44:H 18 , O 78 , O 103 :H 4 and O 127 :H 6. Detected STEC by multiplex PCR for Stx1, Stx2 and eaeA genes; showed different result for each serotype. Salmonella isolation was similar in both beef and poultry 10% (2/20), its serotypes were S. Typhimurium, S. Enteritidis and S. Montevideo with applied of multiplex PCR for invA, hliA and fimH as virulence genes. The other enteric bacteria were prevalent in 35% (7/20) of examined meat samples; one Citrobacter freundi and also one Serratia liquefaciens and Enterobacter agglomerans with percentage of (5%) for each, two Enterobacter aerogenes and also two Proteus morabilis with percentage of (10%) for each. While, from poultry samples enteric bacteria constituted 10% (2/20) as one Enterobacter aerogenes and one Klebsiella pneumonia with percentage of 5% for each one. This obtained data indicated that the microbiological quality of analyzed raw beef samples had high unsatisfactory result than poultry meat samples, and both could be an important cause of food borne disease. Good manufacturing practices (GMP) for Egyptian hotels should be applicable and food handler's health screening have to be made to control pathogenic microbes which potential for public health risks.
To evaluate the hygienic status during preparation of food in fixed and floating hotels from Kitchen area in Luxor, Egypt; one hundred samples were collected; 20 from each raw beef, chicken meat, surface, hand and knife swabs (10 from each, fixed and floating). The meat samples were examined for the Aerobic plate count (APC), Coliforms count (CC) and Coagulase Positive Staphylococci (CPS). As the results indicated that the count varies from satisfactory to unsatisfactory according to the parameter mentioned in Egyptian standards of frozen meat (ES 1522/2005) and (Egyptian standards of frozen poultry) ES 1090/2005, also, the meat samples were examined for the important food borne pathogens (E.coli, Salmonella spp. and other enteric bacteria). The results indicated higher percentage in beef than poultry for E.coli isolation 20% (4/20) and 15% (3/20), respectively; its serotypes are O26: H11, O44:H18, O78, O103:H4 and O127:H6. Detected STEC by multiplex PCR for Stx1, Stx2 and eaeA genes; showed different result for each serotype. Salmonella isolation was similar in both beef and poultry 10% (2/20), its serotypes were S. Typhimurium, S. Enteritidis and S. Montevideo with applied of multiplex PCR for invA, hliA and fimH as virulence genes. The other enteric bacteria were prevalent in 35% (7/20) of examined meat samples; one Citrobacter freundi and also one Serratia liquefaciens and Enterobacter agglomerans with percentage of (5%) for each, two Enterobacter aerogenes and also two Proteus morabilis with percentage of (10%) for each. While, from poultry samples enteric bacteria constituted 10% (2/20) as one Enterobacter aerogenes and one Klebsiella pneumonia with percentage of 5% for each one. This obtained data indicated that the microbiological quality of analyzed raw beef samples had high unsatisfactory result than poultry meat samples, and both could be an important cause of food borne disease. Good manufacturing practices (GMP) for Egyptian hotels should be applicable and food handler's health screening have to be made to control pathogenic microbes which potential for public health risks.
To evaluate the hygienic status during preparation of food in fixed and floating hotels from Kitchen area in Luxor, Egypt; one hundred samples were collected; 20 from each raw beef, chicken meat, surface, hand and knife swabs (10 from each, fixed and floating). The meat samples were examined for the Aerobic plate count (APC), Coliforms count (CC) and Coagulase Positive Staphylococci (CPS). As the results indicated that the count varies from satisfactory to unsatisfactory according to the parameter mentioned in Egyptian standards of frozen meat (ES 1522/2005) and (Egyptian standards of frozen poultry) ES 1090/2005, also, the meat samples were examined for the important food borne pathogens (E.coli, Salmonella spp. and other enteric bacteria). The results indicated higher percentage in beef than poultry for E.coli isolation 20% (4/20) and 15% (3/20), respectively; its serotypes are O 26 : H 11 , O44:H 18 , O 78 , O 103 :H 4 and O 127 :H 6. Detected STEC by multiplex PCR for Stx1, Stx2 and eaeA genes; showed different result for each serotype. Salmonella isolation was similar in both beef and poultry 10% (2/20), its serotypes were S. Typhimurium, S. Enteritidis and S. Montevideo with applied of multiplex PCR for invA, hliA and fimH as virulence genes. The other enteric bacteria were prevalent in 35% (7/20) of examined meat samples; one Citrobacter freundi and also one Serratia liquefaciens and Enterobacter agglomerans with percentage of (5%) for each, two Enterobacter aerogenes and also two Proteus morabilis with percentage of (10%) for each. While, from poultry samples enteric bacteria constituted 10% (2/20) as one Enterobacter aerogenes and one Klebsiella pneumonia with percentage of 5% for each one. This obtained data indicated that the microbiological quality of analyzed raw beef samples had high unsatisfactory result than poultry meat samples, and both could be an important cause of food borne disease. Good manufacturing practices (GMP) for Egyptian hotels should be applicable and food handler's health screening have to be made to control pathogenic microbes which potential for public health risks.
The objectives of this study were to isolate and identify Salmonella spp. from broiler carcasses, wings and liver samples by immunomagnetic separation based cultivation technique, to verify the isolates as Salmonella spp. by the detection of oriC gene by PCR, to identify the isolates using malic acid dehydrogenase and DT104 specific primers as S . Typhimurium and S . Typhimurium DT104. Also to determine the two important virulence genes, virulence plasmid ( spvC ) and invasion ( invA ) for molecular characterization, to evaluate the antibiotic resistance profiles of the isolates. For this purpose, 110 broiler carcasses, 110 broiler wings and 110 broiler liver samples with a total number of 330 were analyzed. Ninety six (29.1%) of the samples were detected as contaminated with Salmonella spp. According to the results 11 isolates (11.4%) were identified as S . Typhimurium. None of these serotypes were determined as specific phage type DT104. InvA gene was detected from all the (100.0%) Salmonella isolates and 14 isolates (14.6%) were detected as positive for spvC gene. Eighty‐three isolates (86.4%) were resistant to at least 5, 70 isolates (72.9 %) resistant to at least 7 and 36 isolates (37.5%) were resistant to at least 9 antibiotic.
Practical Application
This work is significant because Salmonella is still an important public health problem all around the world. This study would provide some data about the incidence of S . Typhimurium and S . Typhimurium DT104 in chicken meat and parts and the antibiotic resistance of the isolates in Turkey. Besides, the method used in study and the parts chosen for analysis would be a model for the other researchers who are thinking to study in this area.
A total of 1666 samples were examined, of which 512 samples of parenchymatous organs of dead or deliberately sacrtificed animals, 60 samples of non-hatched fertilized eggs, 202 samples of feces, 652 samples of cloacal smears, 221 samples of smears from walls of maintenance objects, incubator stations, and transport vehicles, 19 samples of beddings and shavings. The samples originated from poultry farms and which were taken to a laboratory immediately on sampling and sown the same day. A total of 104 strains of Salmonella were isolated: 94 strains from samples of parenchymatous organs of dead chicks, 1 strain from non-hatched eggs, 3 strains from feces samples, 1 strain from samples of cloacal smears, 4 strains from samples of surface smears of maintenance objects and transport vehicles, and 1 strain from samples of beddings and shavings. Serological typization established the presence of the following serovarieties: Salmonella Enteritidis 79 strains, Salmonella Hartford 17 strains, Salmonella Typohimurium 5 strains, Salmonella Mbandaka 2 strains, and Salmonella Glostrup 1 strain. We examined the sensitivity of Salmonella strains to ampicillin, amoxicillin, gentamycin, streptomycin, neomycin, enrofloxacine, norfloxacine, flumequin, erythromycin, lincospectin, colistin, fluorphenicol, and a combination of sulphamethoxasole and trimethoprim. In S. Enteritidis strains, no resistence was established to colistin, fluorphenicol and sulphamethoxasole+trimethoprim, in fact, the sensitivity to these antibiotics and chemotherapeutics was 100%. Prevalence resitence of 0.96%, in only one strain, was established for enrofloxacine. A high prevalence resistence of 33.6% was established for neomycin, while prevalence resistence of 3.86% was established for the related aminoglycozide antibiotic gentamycin. The highest prevalence resistance in S.Hartford strains was established for erythromycin, 15.38%, and streptomycin, 7.6%. Resistence of S. Tyohimurium was established for flumequin and erythromycin in 1.9% strains. No resistance to antibiotics was established in the strains S. Mbandaka and S. Glostrup.
The genus Salmonella are rod-shaped facultative anaerobes enterobacteria that are obligatory intracellular parasites and worldwide distributed. These pathogens are considered of great importance for animals as for humans. In broiler industry, Salmonella normally cause no harm to poultry, but are involved in foodborne diseases in humans and represent a significant public health problem. The main source of transmission to humans is the consumption of eggs, followed by bovine meat and chicken. Control of this disease is complex because of its wide distribution, making it necessary to adopt preventive measures, because once present in the production chain of poultry industry, the health management for control of Salmonella is expensive. In general, clinical signs of salmonellosis are associated with the gastrointestinal tract, but systematic infection can occur with death. The losses are high for both poultry industry and for public health, and the best way to reduce costs are related to the disease is by adopting preventive measures rather than curative measures. The objective of this review is to show the importance of avian Salmonella in public health.
The aim of the study was to compare Polymerase Chain Reaction (PCR) and conventional method for detection of Salmonella from field poultry samples (n = 510, poultry blood and faeces 255 each). The prevalence rate of Salmonella in chicken was found to be 5.09% using1 conventional method and 5.88% by PCR assay. Serotyping of 26 Salmonella isolates revealed 57.69% Salmonella Typhimurium, 19.23% rough type, 15.38% Salmonella Enteritidis and 7.69% untypable. Among Salmonella Typhimurium isolates, 73.33% were from poultry blood and 26.66% from faeces samples. All isolates belonging to Typhimurium and Enteritidis serotypes were confirmed by PCR targeting of Salmonella Typhimurium (typh) and Salmonella Enteritidis (ent) specific genes. However, 4 isolates found to be rough type also turned out to be positive for ent gene. The PCR employed for detection of Salmonella was found 100% sensitive for poultry blood but its sensitivity was very less (77.77%) for faeces samples as compared with culture method. However, PCR was 100% specific with regard to faeces samples. The specificity from blood samples was 97.89% by PCR. The positive predictive values of PCR from blood and faecal samples were 77.27 and 100% with a concordance of 98.03 and 99.21%, respectively. The negative predictive values from blood and faecal samples were 100 and 99.19%. The study demonstrated usefulness of genus specific PCR for detection of Salmonella in poultry clinical samples. Owing to its robustness and rapidity it can be used for wide epidemiological studies. Serotype specific PCR detection of Typhimurium and Enteritidis serotypes has added advantage in identifying them even where there is loss of O antigen.
Commercial bivalent killed Salmonella vaccine Salenvac-T has been used in several countries in order to prevent salmonellosis with Salmonella enterica serovars Enteritidis (SE) and Typhimurium (ST) in poultry. However, this vaccine has not been used in poultry farms in South Korea. In this study, we evaluated the efficacy of Salenvac-T vaccine to protect against the challenge of virulent SE and ST, and the effect of the vaccine on egg production and mortality in layer hens. The colonization of liver, spleen and cecum with challenged SE and ST was reduced in vaccinated chickens compared with that of unvaccinated control group. The twice vaccination with Salenvac-T induced elevated antibody responses against both SE and ST detected by enzyme-linked immunosorbent assay (ELISA). The higher average hen-day production was observed in the vaccinated layer hens than in the unvaccinated layer hens without significance. The average mortality was lower in the vaccinated layer hens during the experiment period. The antibody responses to both SE and ST were persistently detected in the vaccinated layers. In summary, vaccination with Salenvac-T reduces colonization of internal organs and induces good antibody responses, thereby results in higher performance and lower egg contamination with SE and ST in layer hens.
The growth of S almonella in chicken meat at different temperatures and water activities was studied. The DMFit software (Institute of Food Reseach, Norwich, UK), based on the B aranyi model, was used to fit growth curves and obtain growth parameters. When temperature or water activity increased, the maximum growth rate increased and the lag time decreased. The developed secondary model was validated by published reports and 422 data from C om B ase, which suggest that the model could be used to safely predict the growth of S almonella in chicken. In this study, the correlation between growth parameters and growth conditions was also investigated using unified and separated models. These models were validated using a different S almonella strain, isolated from chicken meat, and also with independent data from literatures and C om B ase. The values of accuracy and bias factor are 0.99, 1.22 for unified model, and 0.98 and 1.08 for separated model, which suggested the predictions of the models were in a safe and acceptable range. The evaluation suggested robustness of the models and the statistical results of the models show goodness‐of‐fit.
Practical Applications
There is no significant difference between unified and separated models, so the data tested in laboratory media could be easily used in real food after the mathematical process using unified model. This is important in predictive microbiology, as it can be readily used to control the potential hazard in food and maintain food safety.
The antioxidant potency, anti food borne bacterial activity, and total phenolic contents of essential oils (EOs) from avishane shirazi (Zataria multiflora), clove (Syzgium aromaticum), cinnamon (Cinnamomum zeylanicum), cumin (Cuminum cyminum), black cumin (Bunium persicum), spearmint (Mentha spicata), horsemint (Mentha longifolia), coriander (Coriandrum sativum), sage (Salvia officinalis), and ginger (Zingiber officinale) were evaluated. In 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, free radical scavenging activities of clove and avishane shirazi EOs were 90.69% and 88.63%, respectively. In reducing power assay, the EO of clove showed the highest reducing capacity. The highest concentrations of total phenolics (66.01 mg and 44.81 mg GAE/gram sample) were also detected for the EOs of clove and avishane shirazi, respectively. The results of disc diffusion assay showed that the EOs of avishane shirazi, cinnamon, and clove strongly inhibited growth of the tested bacteria. The EO of cinnamon had the lowest minimal inhibitory concentration (MIC) (0.312 mg/mL).
In this study, we evaluated the Salmonella detection capability and compatibility of a LightCycler polymerase chain reaction (LC PCR) system with two bacteriological methods, United States Food and Drug Administration's Bacteriological Analytical Manual Chapter 5: Salmonella (FDA) and International Organization for Standardization Method 6579 (ISO). The aim was to determine which bacteriological method would support LC PCR for testing naturally contaminated poultry and red meat samples with Salmonella. Twenty three (50.0%) and 24 (52.2%) out of 46 chicken meat samples were positive for Salmonella by the FDA and ISO methods, respectively. Five of the 15 (33.3%) turkey meat samples were found to harbor Salmonella by both bacteriological methods. None of the red meat samples were positive for Salmonella using the FDA method. There was one red meat sample (3.3%) positive for Salmonella using ISO method. LC PCR results indicated that 23 (50.0%) and 31 (67.4%) of the DNA templates obtained from the 46 preenriched chicken meat FDA and ISO samples were positive for Salmonella. Salmonella detection rate from turkey meat samples by ISO LC PCR was 6.7%, whereas no detection was observed by FDA LC PCR. FDA LC PCR detection rate in red meat samples was 23.3%, whereas the ISO LC PCR was 43.3%. Relative accuracy rates of ISO LC PCR and FDA LC PCR were 67.4%, 60.0%, 53.3% and 56.5%, 66.7%, 76.7% for chicken, turkey, and red meats, respectively. We presume that the low relative accuracy problem, which can be related to the use of FDA and ISO preenrichments for template preparations in the PCRs, can be overcome by the use of primary enrichments of both FDA and ISO bacteriologies.
An automated immunomagnetic separation (IMS) and enzyme immunoassay (EIA) was applied to the detection of Salmonella enterica subspecies enterica serotypes from poultry environmental samples. The analytical sensitivity and specificity of the IMS-EIA for 46 S. enterica serotypes and 33 non-salmonellae isolates belonging to 21 different genera were 91.3% and 90.9%, respectively. From post enrichment S. enterica cultures, the limit of detection of the assay was estimated at 10(4)-10(6) CFU/mL. Application of IMS-EIA on 850 naturally contaminated poultry environmental samples achieved 98.4% sensitivity and 96.8% specificity, as compared with a standard culture reference method performed concurrently on the same set of samples. The IMS-EIA described, allows for the identification of suspect positive samples within 48 h of testing versus 4-6 days required by standard culture methods while significantly reducing the materials and labour required for the detection of S. enterica serotypes in poultry environmental samples.
A study was conducted in 2006 to determine the prevalence of Salmonella on three cantaloupe farms in Matamoros, Coahuila, Mexico, and on one farm that cultivates chile peppers var. Bell in Culiacán, Sinaloa, Mexico. Samples from cantaloupe farms consisted of cantaloupe rinses, irrigation water, water from furrows in the field, and workers' hands. Samples from the chile pepper farm consisted of rinses of chile peppers obtained at the field, pepper rinses obtained at the packing house, and irrigation water from the field. A total of 55 samples were obtained from both production systems. Twelve and 10 samples from the cantaloupe and chile pepper production systems, respectively, tested positive for Salmonella according to a traditional culture method. The difference between the proportion of Salmonella-positive samples from the cantaloupe production system (12 of 28 = 0.43) and the chile pepper production system (10 of 27 = 0.37) was not statistically significant (P > 0.05). A PCR-restriction fragment length polymorphism (RFLP) method based on the fliC gene was used to determine the serotype of the isolates. Salmonella Typhimurium was the only serotype found associated with the cantaloupe production system, whereas both Salmonella Typhimurium and Enteritidis serotypes were found associated with the chile pepper production system. Results showed that 91% (20 of 22) and 9% (2 of 22) of the isolates from both agricultural systems matched with the Salmonella Typhimurium and Salmonella Enteritidis reference strain restriction profiles, respectively. This study demonstrates the utility of the PCR-RFLP technique for determining the serotypes of Salmonella isolates obtained from cantaloupe and chile pepper production systems.
We evaluated a newly developed commercial bivalent killed Salmonella vaccine Oilvax SET for its ability to decrease contamination with Salmonella enterica serovars Enteritidis and Typhimurium in layer chickens. In either an oral or intravaginal challenge model, the fecal shedding was decreased in vaccinated hens, but egg contamination was not evaluated due to scarcity of contaminated eggs even in the unvaccinated control groups. In contrast, an intravenous and an intraperitoneal challenge resulted in the relatively high level of egg contamination in unvaccinated chickens, which was significantly reduced in vaccinated chickens. In a second experiment, 2 strains of Salmonella serovar Gallinarum biovar Pullorum, which has the common O9 antigen with SE and transmits vertically into eggs, were used to test the efficacy of the Oilvax SET against egg transmission. Vertical egg transmission by the Pullorum strain was significantly reduced in the vaccinated groups of hens. The Oilvax SET can be a useful tool in the control of Salmonella egg contamination in laying hens.
We report the isolation of Salmonella enterica serotype Typhimurium phage type DT104 (CCARM 8104) from swine in Korea. The CCARM 8104 isolate was resistant to nalidixic acid and showed reduced susceptibility to quinolones. The CCARM 8104 isolate had a missense mutation, Asp87Asn, in the quinolone resistance-determining region in gyrA and produced PSE-1. The CCARM 8104 isolate carried two different class 1 integrons, and the PSE-1 beta-lactamase gene was inserted into a 1,200 bp class 1 integron. The presence of DT104 with pse-1 in an integron located in a plasmid and reduced susceptibility to quinolone in swine pose a significant threat of possible horizontal spread between swine and humans.
Salmonella typhimurium phage type (PT) or definitive type (DT) 104 is a virulent pathogen for humans and animals, particularly cattle. It has been isolated increasingly from humans and animals in the United Kingdom and several other European countries and, more recently, in the United States and Canada. Humans may acquire the infection from foods of animal origin contaminated with the infective organism. Farm families are particularly at risk of acquiring the infection by contact with infected animals or by drinking unpasteurized milk. The symptoms in cattle are watery to bloody diarrhea, a drop in milk production, pyrexia, anorexia, dehydration and depression. Infection may result in septicemic salmonellosis and, upon necropsy, a fibrinonecrotic enterocolitis may be observed. The infection occurs more commonly in the calving season than at other times. Feedlot cattle and pigs may also be affected. Prolonged carriage and shedding of the pathogen may occur. Symptoms in humans consist of diarrhea, fever, headache, nausea, abdominal pain, vomiting, and, less frequently, blood in the stool. Salmonella typhimurium DT104 strains are commonly resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline.
Salmonella Typhimurium is one of the most important Salmonella serovars that may cause foodborne disease and human salmonellosis infection. Detection of this organism in the clinical samples of persons with gastroenteritis and the food samples associated with such persons may allow us to trace the cause of disease. Because malic acid dehydrogenase, an enzyme of the citric acid cycle, is common to organisms, the gene (mdh) coding for this enzyme was selected for the design of Salmonella Typhimurium-specific polymerase chain reaction (PCR) primers. By comparison of the mdh gene sequences of Salmonella Typhimurium and other Salmonella serotypes and of some isolates of other genera, two oligonucleotides were designed and used as PCR primers for the specific detection of Salmonella Typhimurium. The molecular weight of the PCR product was 261 bp as expected. Salmonella serovars other than Salmonella Typhimurium and isolates of other genera in the Enterobacteriaceae that is closely related to Salmonella did not generate any false-positive results. When this primer pair was used for the detection of Salmonella Typhimurium cells artificially inoculated into human stool specimens and food samples, such as milk and raw chicken meat, levels as low as 10(0) CFU per 0.1 g of stool specimen or per ml of milk or food homogenate could be detected if an 8- to 12-h preculture step using combined lactose-tetrathionate broth was performed prior to the PCR.
A DNA sequence was identified in isolates of Salmonella enterica serotype Typhimurium definitive type 104 (DT104). The PCR amplification of an internal segment of this sequence identified DT104 and the closely related U302 phage type among 146 isolates of S. enterica serotype Typhimurium tested, thus providing a tool for rapid identification of DT104 and related isolates.
Multidrug-resistant Salmonella enterica serovar Typhimurium phage type DT104 has emerged during the last decade as a global health problem because of its involvement in diseases in animals and humans. Multidrug-resistant DT104 strains are mostly resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides and tetracyclines (ACSSuT resistance type). The genes coding for such resistances are clustered on the chromosome. This paper reviews new developments in the characterization of S. enterica Typhimurium DT104, its chromosomal antibiotic resistance genes and their spread among other S. enterica Typhimurium phage types and other S. enterica serovars, the development of specific detection methods, virulence characteristics, and the evolution of multidrug-resistance with regard to the emergence of quinolone resistance.
The phage-typing scheme of Callow (1959) has been extended. The original number of types was 34; this has now risen to 207. Tables are presented which show the provisional type designations and the definitive designations now being introduced.
Selenite-cystine/trimethylamine oxide/dulcitol medium has been used in conjunction with conductance instruments to detect the presence of Salmonella spp. in foods and faeces. However, a small but significant number of salmonella strains were missed by this method. The majority of these strains were detected when dulcitol was substituted by mannitol and tested on two separate Malthus conductance instruments. Some strains of Citrobacter freundii and Escherichia coli continued to give false positive results. Attempts are made to explain why the substitution of mannitol for dulcitol gives an improved medium.
1. A new phage-typing scheme for Salm. typhi-murium is described which initially defines thirty-four types of the organism.
2. Types recognizable with the older scheme of Felix and Callow remain distinct with the new system. However, the latter method offers a finer subdivision of the organism than does the former.
3. Thirteen of the twenty-nine typing phages used in the new scheme were prepared by adaptation of Salm. paratyphi B typing phage 3b, and nineteen are serologically indistinguishable from this phage.
4. The lysogenic properties of the new types are discussed. Twenty-three out of the thirty-three type strains yielded both thermolabile and thermostable phages and a further three yielded thermolabile phages only. No phages could be isolated from the remainder.
5. The distinctive host ranges of the phages carried by most types can be used for type identification.
I am indebted to Miss Alison M. Dykes for her valuable assistance with this work; to Mr F. J. Flynn for help in the preparation of phage stocks; and to Dr E. S. Anderson for many helpful discussions and advice in the preparation of this paper.
Antigenic formulas of the Salmonella serovars. WHO Collaborating Centre for Reference and Research on Salmonella
- Le Minor
- L Popoff
Le Minor, L., Popoff, M.Y., 2001. Antigenic formulas of the Salmonella serovars. WHO Collaborating Centre for Reference and
Research on Salmonella, Paris, 8th ed.
Antibiotic susceptibility of Salmonella strains isolated from animals and their environment
- F Moury
- A Brisabois
- S Fremy
Moury, F., Brisabois, A., Fremy, S., 1997. Antibiotic susceptibility
of Salmonella strains isolated from animals and their environment. Proc. 4th Int. Meet. Bacterial Epidemiological Markers,
Elsinore, Denmark, 10-13, September 1997. p. 138.
The phagetyping of Salmonella other than S. typhi The World Problem of Salmonellosis The Hague, The Netherlands
- E S Anderson
Anderson, E.S., 1964. The phagetyping of Salmonella other than
S. typhi. In: Van Oye, E. (Ed.), The World Problem of Salmonellosis. Dr W. Junk Publishers, The Hague, The Netherlands,
pp. 89-100.
Serologic identification of Salmonella
- Ewing
Antigenic formulas of the Salmonella serovars
- Le Minor
Antibiotic susceptibility of Salmonella strains isolated from animals and their environment
- Moury