Chapter

Egg Production Systems and Salmonella in South America

Authors:
  • CONICET Salta Argentina
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Abstract

The growth of the poultry industry in South America has been explosive in recent years. More than 238 million layers are located in South America producing more than 4 million tons of eggs. Brazil, Argentina, and Colombia are the most important egg producers in this region. Nonenriched cage systems are not prohibited in South America and most of the laying hens are located in battery cage farms, which include automatic and conventional (manual) battery cage systems. Salmonella Gallinarum and Salmonella Enteritidis are the most prevalent serotypes in layer farms. South American countries have different regulations to control Salmonella in their flocks through various National Poultry Improvement Plans. This control is focused on S. Gallinarum biovars Gallinarum and Pullorum, S. Enteritidis, S. Typhimurium, and S. Heidelberg. Inactivated (killed) and attenuated (live) vaccines are available to control Salmonella spp. in poultry in South America, but there are some differences in licensed vaccines.

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... In Europe, these two Salmonella serovars, Enteritidis and Typhimurium, are specifically regulated in laying flocks in all member states [9]. In Argentina, S. Enteritidis and S. Typhimurium represented more than 50% of foods contaminants from 2000 to 2005, and since 2006, S. Typhimurium has been the most frequent serotype isolated from humans, animals, and foods [10]. Nevertheless, the exact cause of the predominance of these Salmonella serovars is not yet clearly understood [11]. ...
... In South American countries, layers are commonly vaccinated with the 9R vaccines against fowl typhoid caused by S. Gallinarum [10]. Furthermore, cross-protection by the 9R vaccine against S. Enteritidis was reported as both serovars belong to the same serogroup [53]. ...
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... The intense international market in food of animal origin facilitates the dissemination of variable strains of Salmonella spp. This context receives greater prominence when considering its relevance in public health, being one of the main pathogens involved in food gastroenteritis, and in the economy of the poultry sector, due to the slaughter and disposal of positive flocks (ABPA, 2020;SVS, 2019;Soria et al., 2017). ...
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This study was aimed to determine the prevalence of Salmonella spp. in foods of animal origin sold at retail stores over the period 2005–2011 in San Luis, Argentina. Characterization of isolates was performed by biochemical and serological tests, antimicrobial susceptibility assays, detection of invA invasion gene by PCR and comparison of genomic profiles by XbaI DNA restriction and PFGE. Twenty seven Salmonella strains were detected in 27 (6.32%) of 427 samples of foods analysed. Sixteen S. Enteritidis and one S. Montevideo strains from chicken meat (17 positive samples/115 total samples), six S. Anatum strains from pork sausages (6/90), two S. Typhimurium strains from liquid egg (2/60) and two S. Montevideo strains from chicken giblets (2/62) were isolated. No Salmonella strains were recovered from chicken carcasses (0/100). Salmonella strains were susceptible to antimicrobials commonly used for clinical treatment. All isolates carried the invA gene. DNA restriction and PFGE analysis revealed similar genomic profiles within each Salmonella serovar regardless of the food type, sampling year, or retail store where samples were purchased, suggesting the possibility of circulation and transmission of clones of limited diversity in our region.
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Contamination of ISA BROWN layer hens by Salmonella spp. and serotyping of the isolated strains were performed in 30 farms. Salmonella detection was done from feces and cloaca swabs. Eggs produced in the farms contaminated by Salmonella spp. were analyzed by culturing the shell rinsing and egg yolk. Salmonella spp. was isolated in eight (23.0%) farms, but was not detected from eggs. S. Enteritidis, which is the most prevalent sorotype associated to human salmonelosis in Paraná State, was not isolated either from birds or eggs analyzed. The sorotypes isolated were Salmonella enterica subsp. enterica (0:3.10) (67.0%), Mbandaka (11.0%), Infantis (11.0%), and Newport (11.0%).
Article
Ten Salmonella enterica serovar Typhimurium isolates producing CTX-M-2 extended-spectrum beta-lactamase were identified from clinical and poultry sources in two distant cities in Brazil between 2003 and 2004. They included two isolates from pediatric patients and eight isolates from poultry or its environment. All isolates exhibited coresistance to non-beta-lactam antimicrobials including tetracycline and trimethoprim/sulfamethoxazole. The CTX-M-2 gene was located on transferable plasmids with sizes between 90 and 170 kb that also carried other resistance determinants in some isolates. By pulsed-field gel electrophoresis, the genetic similarity of the isolates including clinical and poultry ones ranged from 89% to 100%.
Article
To study the evolution of antibiotic resistance in isolates of Salmonella enterica subspecies enterica serovar Typhimurium (Salmonella Typhimurium) obtained in Uruguay between the years 1976 and 2000, and to determine the incidence of class 1 and 2 integrons in the multi-resistant isolates. We studied 258 strains of Salmonella Typhimurium from various sources, isolated between 1976 and 2000. We determined the evolution of antibiotic resistance and the distribution of class 1 and 2 integrons in all isolates by means of disk diffusion assays and PCR. During the period 1989-2000 resistance to streptomycin was 56.8%, tetracycline 13.6%, sulfonamides 11.2%, and ampicillin 7.2%. Resistance to gentamicin, kanamycin, chloramphenicol, and nalidixic acid were lower than 5%; no resistance was detected to fluoroquinolones, oxyiminocephalosporins, and amikacin. These results show a dramatic decrease with respect to values found in the period 1976-1988. In this period, resistance to streptomycin was 63.2%, tetracycline 36.8%, sulfonamides 32.3%, and ampicillin 27.8%. Throughout the two periods, 29 multi-resistant Salmonella Typhimurium strains were isolated harboring some class of integron: 15 strains had only intI2, 11 strains presented both intI1 and intI2, and three isolates only intI1. Our results show a marked decrease in resistance throughout these years, along with a correlation between resistance to different antibiotics and the presence of integrons.
Article
A significant increase in the number of isolations of Salmonella enteritidis has been observed in Argentina since 1986. Outbreaks of foodborne diseases in humans were associated with the consumption of raw or undercooked hens' eggs. Between 1986 and the first 6 months of 1993 there were 150 outbreaks reported, affecting more than 6000 persons. A total of 71.3% of these outbreaks were confirmed by stool cultures, and 47.3% by bacteriological study of the food implicated in the outbreak. A permanent surveillance of salmonellosis is imperative, taking into account the persistence of Salmonella enteritidis isolations in sporadic cases and in new outbreaks.
Article
beta-Lactamases with pIs of 5.4 and 8.1 were detected by hydrolysis of ampicillin and ceftriaxone respectively among cefotaxime resistant serovars of Salmonella spp. suggesting TEM-1 and an unidentified extended spectrum beta-lactamase have spread throughout these strains in Argentina.
Article
Since 1994 an extensive epidemic of infections with Salmonella enteritidis (S. enteritidis) has affected Chile. In order to understand the diversity of infective sources, the possible origin of the epidemic, and the epidemiological relationships between clinical, food, and poultry isolates, we carried out phage typing of three groups of samples: 1) 310 S. enteritidis clinical samples collected between 1975 and 1996, 2) 47 food isolates obtained during S. enteritidis outbreaks, and 3) 27 strains isolated in surveillance studies of poultry-raising establishments. With the clinical samples, a total of 13 phage types were identified, 2 isolates could not be typed, and 1 was considered atypical. The phage types that were identified most frequently were 1 (56.8%) and 4 (31.3%), trailed by type 8 (4.8%) and type 28 (1.9%). Over time and in different regions of the country there were major changes in the distribution of the phage types. In the first years of collection the only phage types registered were 8 and 28, which disappeared around 1980 and then began reappearing sporadically in 1996. With the gradual S. enteritidis expansion that started in 1988, in the central and southern areas of the country phage type 4 began to appear; that type had not been found before in Chile. In 1991 in the northern area of the country phage type 1 began to predominate; it was another type that had not been reported before in Chile. In the food isolates the only phage types identified were 1 and 4, which were also the most common in the poultry isolates. Phage typing of S. enteritidis has proved to be useful in guiding the epidemiological analysis of the infections caused by this pathogen.
Article
Salmonella enteritidis (SE) is a frequent cause of diarrhea, and is transmitted mainly by SE contaminated eggs or poultry meat. The frequency of SE contaminated eggs or chicken meat and the risk for acquiring this pathogen is unknown in Chile. To measure SE contamination in eggs poultry meat and entrails offered in retail markets in the Metropolitan Area during two consecutive years (1998-1999). Samples were placed in sterile bags and transported to the laboratory before 4 hours at 4 degrees C. Microbiologic detection was done using a standard procedure and an immunodetection assay. SE was found in one of 1081 egg samples (0.09%). The contaminated sample was offered in a supermarket under their own commercial name. Six percent of 1154 poultry meat samples were contaminated by SE and 2.3% by other Salmonella serotypes. Entrails had even higher rates with 10.2% of 370 samples harboring SE and 2.7% other serotypes. Total Salmonella sp. isolates and SE isolates declined during 1999. Nine SE phagotypes were identified, predominating types 4 and 7. Eggs and other avian products are contaminated by different SE phagotypes and other Salmonella serotypes, implicating a risk for the consumers (Rev Méd Chile 2000; 128: 1075-83).
Article
Antimicrobial resistance was investigated in 91 Salmonella enteritidis isolates from broiler carcasses, food, human and poultry-related samples originated from South of Brazil. A great proportion of resistant strains was found, 90.1% showing resistance to at least one antimicrobial drug. There was a high resistance to sulfonamides (75.8%) and nitrofurantoin (52.8%). Lower levels of resistance were found for tetracycline (15.4%), streptomycin (7.7%), nalidixic acid (7.7%), gentamicin (5.5%), norfloxacin (3.3%), trimethoprim (3.3%), cefalotin (2.2%), ampicillin (1.1%), and chloramphenicol (1.1%). Resistance to ciprofloxacin was not detected. A total of 51.6% of S. enteritidis strains were multiresistant (resistance to two or more antimicrobial agents) and 18 resistance patterns were found. The highest resistance was found in strains isolated from poultry-related samples, where all strains were resistant to at least one antimicrobial agent. No predominant resistance pattern was related to phage type in our isolates. The high number of antimicrobial resistant S. enteritidis found in Southern Brazil indicates the need for the prudent drugs uses to diminish the development and spread of antimicrobial resistance.
Article
The antimicrobial susceptibility of 94 Salmonella strains isolated from different poultry farms in Chile (broiler and laggin hens) were analyzed by the dilution plates method. Thirty-nine of them were resistant to flumequine, nalidixic acid and oxolinic acid with MIC values higher than 64 microg/ml. These quinolone resistant strains were analyzed in order to determine the presence of mutations in the QRDR region of gyrA gene by AS-PCR-RFLP analysis. 51.3% of the strains showed mutations at codon Ser 83 and 41.0% showed mutations at codon Asp 87. No mutations were observed on codon Gly 81. These mutations were confirmed by sequenciation of one representative strain from different RFLP pattern. Likewise, no double mutations were observed. Over 90% of the quinolone resistant strains presented mutations at the QRDR region of the gyrA gene. Three phenotypically resistant strains did not show any mutations on the QRDR region of gyrA gene. However, other molecular resistant mechanism could be involve. This is the first study that demonstrate the emergency of quinolone and fluoroquinolone resistance in Chilean Salmonella strains isolated from poultry thus indicating the requirement of monitoring programmes in veterinary medicine.
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