African Journal of Microbiology Research

Published by Academic Journals
Online ISSN: 1996-0808
Publications
Chapter
Cowpea is the most important legume crop in the dry areas of West Africa and features in several cereal-based cropping systems of Sudan and Sahel environments. Low availability of phosphorus is a major constraint to crop production, and efforts are being made to identify crop genotypes with tolerance to low P and greater P use efficiency. Two hundred cowpea genotypes differing in plant type and maturity were evaluated at 3 P levels (0 P, 90 kg P ha-1 as rock phosphate, and 30 kg P ha-1 as SSP) in 2002 at Minjibir, Nigeria and at Toumnia, Niger. The results showed large variations in grain and fodder yields was found among the 200 genotypes. Grain yield response to RP and SSP ranged from 1 to 160%. Based on the performance at low (0 P) and high phosphorus levels (SSP), genotypes were classified into the following groups: i) inherently low yielding at low (0 P) and high P, ii) inherently high yielding at low and high P, iii) low yielding at low P but high yielding at high P, iv) high yielding at low P, but low yielding at high P, and v) inherently moderate yielding. Fifteen genotypes were selected from the different P use and response groups and further evaluated in the greenhouse and field studies for tolerance to low P and response to applied P. In general, application of P increased grain yield, shoot-root ratio but decreased AMF colonization of cowpea roots. There were large differences in P use efficiency and the values ranged from –11 to 38 kg grain (kg P)-1 applied. AMF infection was reduced by at least 50%, while shoot-to-root ratio was significantly increased with P application. Variation between genotypes was significant for certain paired means but not consistent for all parameters measured, and the locations. The cowpea genotypes appeared to differ in AMF colonization, shoot growth relative root development, and relative P use efficiency for tolerance to low P soils and response to external application of P.
 
Article
Flow cytometry's (FCM) measurement of membrane potential (MP) and cell respiration viability based on continuous culture was used to investigate the responses of aerobic anoxygenic phototrophic bacteria (AAPB) in the heterotrophic growth and regulation mechanism of photosynthesis to environmental changes. An AAPB strain Erythrobacter sp. JL475 and a non-AAPB strain Erythrobacter sp. JL316 were used as the experimental bacteria, both of which were isolated from the South China Sea. The results showed that light-cultured AAPB showed higher MP and biomass at 10 degrees C, suggesting an obvious stimulation of light on AAPB growth. By contrast, dark-cultivated JL475 had higher MP and biomass at higher temperature (20, 30 and 40 degrees C). The rate of heterotrophic respiration at different temperature environment ranked as follows: dark-cultivated JL316 > dark-cultivated JL475 > light/dark cycling cultivated JL475. Light undoubtedly increased the cell viability of AAPB, especially of apoptosis cells. The CTC+% at different carbon concentration ranked as follows: light/dark cycling cultivated JL475 > dark-cultivated JL316 > dark-cultivated JL475. It was concluded that the heterotrophic respiration would played a key role in energy metabolism of AAPB, photosynthesis may provide an advantage for AAPB to survive in a variety of diverse environments. MOST [2007CB815904, 2006BAC11B04]; SOA [200805068]; NSFC [40632013]; MOE [704029]
 
Article
The aim of this study was to isolate enterococci and Escherichia coli from faeces collected from commercial and communal pigs, and to characterise these isolates using antibiotic susceptibility profiles. Enterococcus selective agar and eosin methylene blue lactose agar were used for enterococci and E. coli isolation, respectively. Gram staining, API 20 Strep and API 20E were used for identification of enterococci and E. coli, respectively. Three-hundred-and-four enterococci and 208 E. coli were identified. The most prevalent enterococci species were Enterococcus faecium (58%) and Enterococcus gallinarum (23%). A large proportion of enterococci (62.5% to 100%) and E. coli (88.5 to 100%) were resistant to erythromycin, oxytetracycline and sulphamethoxazole. No vancomycin-resistant enterococci were found and PCR analysis for vanA, vanB and vanC-1 were all negative. Less than 7% of enterococci were resistant to ampicillin and amoxicillin, whereas 45% of E. coli isolates were resistant to the same antibiotics. Antibiotic susceptibility tests and clustering patterns showed some similarities among these isolates. From the results, a common origin of the isolates or histories of antibiotic use among these farms was proposed. It could also be concluded that vancomycin-resistant enterococci were not present in pigs on these two farms.
 
Article
This research has been designed and conducted as a randomized controlled trial to evaluate the effect of three regimens of cord care on cord separation time and umbilical cord colonization. Umbilical cord cares of 70% alcohol, 10% povidone-iodine and 0.4% chlorhexidine were applied to 40 term neonates who were randomly assigned (N = 120). Wipe samples were taken from babies just after the delivery and re-taken from umbilicus on the 5th day, and the separation time of umbilical cord was determined. The mean time to cord separation was significantly higher in the 70% alcohol group (7.10 +/- 1.61, p < 0.05). There were significant differences between the groups considering the culture results on the 5th day (p < 0.05); coagulase-negative staphylococci reproduced in a substantial part (27.5%) of the babies applied with 70% alcohol cares. Alcohol use delayed the time for cord separation compared to other methods. The authors concluded that 0.4% chlorhexidine may be effectively and safely used for umbilical cord care of healthy term neonates.
 
Article
Sporocytophaga sp., a Gram-negative aerobic cellulose decomposing bacterium, is capable of gliding on the surface of solid medium. A new endoglucanase, carboxymethylcellulase (CMCase1), was purified from an aerobic bacterium Sporocytophaga sp. JL-01. The molecular weight of the enzyme was 82 kDa as determined by SDS Polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH was 5.0 and optimum temperature was 50 degrees C under experiment conditions. The Km of CMCase1 was 9 mgmL(-1) and Vmax was 27.3 ug min(-1)mg(-1) protein. The Zn2+ could inhibit the activity of this enzyme at ion concentration of 5 mM. RP-HPLC revealed that aromatic amino acid, acidic amino acid, and basic amino acid accounted for 10.5, 24.5 and 7.0%, respectively. The far-UV circular dichroism (CD) spectrum showed that the amount of beta-sheet was decreased with the temperature changed from 25 to 75 degrees C.
 
Article
White rot basidiomycetes have unique ability to decolorize synthetic industrial dyes. Initial experiment was performed with five locally isolated indigenous white rot species fungi S. commune IBL-01 (SC), P. ostreatus IBL-02 (PO) P. chrysosporium IBL-03 (PC), T. versicolor IBL-04 (TV) and G. lucidum IBL-05 (GL), for the selection of white rot fungal cultures based on their maximal decolorization potential. Based on the screening experiment, two white rot fungi P. ostreatus IBL-02 and P. chrysosporium IBL03 (PC) showing maximum decolorization of dye under study were selected. A comparative study was conducted for the selected white rot fungi to get the maximum decolorization of synthetic azo dye. Different fermentation conditions and nutritional factors were optimized to enhance the efficiency of white rot fungal cultures for dye decolorization. Both cultures produced all the three major ligninolytic enzymes including lignin peroxidase (LiP), manganase peroxidase (MnP) and laccase which are responsible for decolorization process. Under optimum conditions fermentation conditions, P. ostreatus IBL-02 (PO) and P. chrysosporium IBL-03 (PC) decolorized the azo dye by 92.7 and 85.9%, respectively.
 
Article
An objective of this study was to develop high cellulase-producing bacteria by mutagenesis and optimization studies. Among 328 mutant strains of Cellulomonas sp. TSU-03, the mutant M23, NTG mutant, gave the highest value of cellulase activity 2008 U/mg protein) followed by mutant M17 (1884 U/mg protein) in CMC medium. The optimum medium and environmental conditions for cellulase production consisted of 4% wastepaper, 1% NaNO3 under cultivation temperature at 35 degrees C with initial pH and agitation speed at 6 and 100 rpm, respectively. Cellulomonas sp. strain M23 produced the highest cellular growth (28.09 +/- 2.28 g/L) and FPase, CMCase as well as, beta-glucosidase activities at 325, 2420 and 152 U/mg protein, respectively. Under optimal condition, the cellulase activity achieved from strain M23 is 1.28- and 1.30- fold higher than cellulase from mutant M17 and wild type, respectively. After being subcultured 12 times, the cellulase production of the mutant M23 was stable. The results suggested that Cellulomonas sp. M23 had a good potential for production of cellulase by fermentation using a cultivation medium containing wastepaper as the main substrate.
 
Extracellular protein content and cellulolytic activities of P.ostreatus at different avicel concentration. Under shaked condition. 
(A) Scanning Electron microscope mycelial net work, (B) Mushroom fruit bodies Pleurotus ostreatus cultivated on rice straw.  
Enzymatic activities and extracellular protein of P. ostreatus versus the time of fermentation. 
Article
Successful utilization of Pleurotus ostreatus (Jacq.) P. Kumm. (type NRRL-0366) mushroom as a type of edible locally isolated mushroom in Egypt at the Mushroom Research Center (Mubarak City for Scientific Research and Technology Applications), to produce extensive hydrolyzing cellulase complex enzymes. This hydrolysis was approached in submerged culture supplemented with avicel PH101 as a substrate for endo-,exoglucanase production. The avicel concentration 6% yielded the maximum enzyme activities (2.46, 1.80 U/ml) for both endo-and exoglucanase activitieson basal medium at 27°C, initial pH value of 5.5 for 12 days on rotary shaker (180 rpm) incubation period. Cellulase enzyme was amplified using specific PCR and the amplicone was cloned using TOPO TA cloning vector. The cellulolytic activity of the recombinant protein was examined and high activity was obtained compared with the standard ones. The avicel was used as a sole carbon source in the fermentation medium and the results revealed that, avicel induced the cellulolytic activity of the examined organism compared with those grown on medium deficient of avicel.
 
Article
Recently, an increasing interest in “green” processes for the production of chemicals was observed. An attractive solution is microbial fermentation processes which use renewable feedstocks such as glycerol. However, this kind of synthesis has several limitations, among others a small range of products, low productivities, as well as difficulty in recovery and purification of products. One way to overcome these limitations is the application of metabolic engineering. This paper is a review of 1,3Propanediol (1,3-PD) characteristic and applications, of microorganisms which ferment glycerol to 1,3PD and their metabolic pathways, and finally of the metabolic engineering methods for the microbial conversion of raw glycerol to 1,3-PD.
 
Article
Urinary tract infections (UTIs) are one of the most common infectious diseases diagnosed in communities and hospitalized patients. The aim of this study was to determine frequency of occurrence and antimicrobial susceptibility patterns of uropathogens in Milad hospital of Tehran, Iran. In a prospective study from March to June 2009, a total of 11308 urine sample from patients admitted in Milad hospital of Tehran were analyzed. All specimens were inoculated on routine culture media. Bacterial isolates were identified by conventional bacteriological methods. Susceptibility testing was performed by standard methods as recommended by clinical laboratory standard institute. 11308 urine samples were cultured and 1020 pathogen were isolated. Escherchia coli with 620 (60.78%) isolates was the most common causative agent of UTI followed by Klebsiella pneumoniae with 115 (11.27%) isolates. Among gram positive Cocci Enterococcus spp with 110 (10.78%) isolates and Staphylococcus aureus with 81 (7.94%) isolates were predominant organisms. Of 1020 patients, 227 (22.25%) were male and 793 (77.74%) were female. Of 1020 patients, 224 (21.96%) of patients were hospitalized and 796 (78.03%) were outpatients. Of 224 hospitalized patients, 85% of isolates of E. coli were resistant to ampicillin, while this figure was 90% for K. pneumoniae. Resistant to other antibiotics were also prevalent. Nitrofurantoin was the most effective antibiotics against E. coli and Enterococcus spp. In conclusion, our study revealed that bacterial resistance in uropathogens in our hospital continues to be a great problem and needs drug resistance surveillance periodically.
 
Article
-1 . Streptomyces isolates were screened for producing β-lactamase inhibitory effect against P. aeruginosa ATCC-10145. There were ten Streptomyces isolates which had inhibitory effect. Although, one Streptomyces isolate has been considered the most potent, this was identified by using biochemical characteristics as Streptomyces chromofuscus. Optimization factors for maximum yield of β-lactamase inhibitory protein were studied. The best incubation period at 7th day, incubation temperature at 28°C, pH value at 6.8, the best carbon source was galactose and the best nitrogen source was prolin. The highest amount of β-lactamase inhibitory protein was precipitated at 40% of saturated ammonium sulphate. The purification was carried out by using both diethylaminoethyl-cellulose and sephadex G-200 column chromatography, respectively. The β-lactamase inhibitory protein was separated at 32 KDa. The purified β-lactamase inhibitory protein was characterized as tazobactam. The combination of tazobactam at 128 mg.L -1 and amoxicillin at 125 µg.ml
 
Article
Antimicrobial resistance has become a serious public health concern all over the world. The objective of this study was to determine susceptibility patterns of microorganisms to antibiotics in 11 hospital laboratories in Kurdistan province. During one month period (February, 2010), all the clinical specimens which were received from the laboratories were processed for isolation and identification of bacteria to the species level by standard methods. Testing procedures were validated following the Kirby-Bauer disc diffusion technique using Muller Hinton agar. Susceptibility testing was performed on Mueller Hinton agar. A total of 4395 clinical specimens were obtained from 4301 patients among them, 1062 (24.7%) were male and 3239 (75.3%) were female, giving on overall male to female ratio of 0.32. Their mean age was 31.3 years (range: 4 to 74 years). Based on data 310 pathogens were isolated and Escherichia coli 183 (59.3%), followed Klebsiella pneumoniae 40 (01.29%) and Staphylococcus aureus 39 (1.25%) were the predominant isolated bacteria. The most resistant antibiotics tested against isolated bacteria were penicillin, ampicillin, and amoxicillin. Lastly, these resistance rates leave imipenem and ciprofoxcacin as the reliable agent for the empirical treatment in this province. The present study has shown that the urinary tract infection (UTI) patients have a higher rate of infection. The risk of antibiotic resistance in isolated bacteria, particularly E. coli, emphasizes the importance of hospital control measures and rational prescribing policies. Lastly, these resistance rates leave ciprofloxcacin and imipenem as the reliable agent for the empirical treatment in this province.
 
Article
The aim of this study was various nutrients belonging to three categories, carbon, nitrogen and amino acid sources, were investigated in terms of their effect on the production of extracellular β-galactosidase by Bacillus licheniformis ATCC 12759. Amongst simple carbon sources, xylose and galactose supported maximum β-galactosidase production. Comparison with the control there was significant increase in enzyme yield in the case of the supplementation complex carbon source such as rice flour. Among the amino acid sources tested L-tryptophane, L-cysteine, L-phenylalanine, L-lysine, L-valine and L-tyrosine were favored the production respectively. In media containing the all organic and inorganic nitrogen sources resulted in a decrase production of β-galactosidase. FeSO 4 , ZnSO 4 and CuSO 4 supressed β-galactosidase production. Maximum β-galactosidase production (2.508.3 ± 29.9 U/mg) was obtained in a medium containing 0.01% L-tryptophane in 72 h 37°C.
 
Article
Biomass yields and sporulation of Pochonia chlamydosporia isolate HSY-12-14 was concerned on culture conditions including culture method, nutritional requirements together with environmental factors in this study. We optimized them for biomass yields of P. chlamydosporia HSY-12-14 with the "two-step" cultivation method as well as orthogonal matrix method: firstly cultured spore suspension on the basal medium (sucrose 19.00 g, soy peptone 4.06 g, K(2)HPO(4) 1.00 g, KCl 0.50 g, MgSO(4) 0.50 g, FeSO(4) 0.01 g and 17.00 g Bactor) for the first stage culture of 4 days under room condition, then transferred them to another defined medium (sucrose 19.05 g, soypeptone 0.01 g, ZnSO(4)center dot 7H(2)O 0.05 g/L, MnSO(4)center dot H(2)O 0.05 g/L, H(3)BO(4) 0.05 g/L and 17.00 g Bactor) for more 4 days cultivation, together with the environmental factors combination of water potential -3.9 MPa /pH 4 /24 h light cycle/23 degrees C for biomass yields. We optimized the best culture conditions for sporulation of P. chlamydosporia under water potential -1.2 MPa /pH 4 /24 h light cycle/32 degrees C wit h the same nutrition for biomass yields. These results is characterized in that it supplies the composition of media and environmental suitable for the mass production and provide important information industrialization of this great potential biocontrol fungus.
 
Article
The 14-3-3 proteins are a group of highly conserved and widely distributed eukaryotic proteins with diverse functions. In plants, it regulates basal metabolism, ion transport, cell passage, enzyme activity and gene expression, and it is also important in disease resistance, anti-oxidation and drought resistance. Based on assembled sequences of sweet potato (Ipomoea batatas L. Lam) transcriptome, 14-3-3 protein cDNAs were cloned for the first time, and the sequencing analysis revealed the presence of three highly homologous isoforms of 14-3-3 protein cDNAs, designated as Ib14-3-3a, Ib14-3-3b and Ib14-3-3c. Three cDNA isoforms are all 1176 bp in length with 7 mutation sites and have a 789 bp of open reading frame encoding a polypeptide of 262 amino acids. The results from digital gene expression (DGE) profiling showed that the expression levels of 14-3-3 genes are different among tissues, predominantly in harvested tuberous roots (223.08 TPM) and very low in mature leaves (85.07 TPM) , which were also confirmed by semi-quantitative Reverse transcription polymerase chain reaction (RT-PCR) analysis.
 
Article
Marine actinomycetes strains of Streptomyces indiaensis ACT 7 and Streptomyces hygroscopicus ACT 14 were efficiently utilized for the bioremediation of dairy industry effluent. The effluent characterization before and after the treatment were observed. The maximum reduction of TS, TDS, TSS, biological oxygen demand (BOD), chemical oxygen demand (COD), chloride, oil and fat content were observed for effluent treatment by mixed consortium. It showed the reduction percent of 92.57 and 90.73 for BOD and COD, respectively. The untreated and treated effluent was used for the germination of Vigna radiata. The seed germination of 100 and 70% were observed for treated and untreated effluent studies. The seedling length (27.2 cm) and vigour index (2720) was maximum for V. radiata treatment with treated dairy effluent.
 
Article
To investigate clinical features, laboratory, and imaging characters in Chinese children, we conducted a retrospective study on 14 children with acute focal bacterial nephritis (AFBN) admitted in Beijing Children’s Hospital during January 2005 to December 2009. Six girls and eight boys with a mean age of 4.7 years (range: 0.3-11.4 years) were followed up on average 1.7 years (range: 0.5-3.5 years). Leukocyturia was found in 10/14 children. Urine cultures were positive in 10/14 cases; E. coli was the most common cause of AFBN. A combination of nephromegaly and focal mass was found in 11/14 patients. Urinary tract anomalies were found in 8 children. Two boys had underlying disease of acute lymphatic leukemia under chemotherapy. AFBN resolved on average 3-12 weeks after therapy. Ultrasound and enhanced CT were not necessary in cases of fever of unknown origin, even if pyuria nor urine culture is positive. Vesicoureteral reflux (VUR), malignancy and renal vascular malformation are potential risk factors of AFBN; careful radiological investigations should be performed.
 
Article
A parasitic copepods study of Algerian teleost fish, report 25 copepod species belonging to eight families harvested from the gills of 14 fish species. The analysis of species richness according to some ecological, biological and taxonomical variables (Diet, Displacement, Way of life, Family) of the whole of hosts are reported in this study, the differences between mean specific richness (MSR) of all variables is statically significant according to Kruskal-Walis test using sigma stat software. Parasitic specificity is discussed, infestation parameters were described.
 
Article
The 14-3-3 proteins are a group of highly conserved and widely distributed eukaryotic proteins with diverse functions. In plants, it regulates basal metabolism, ion transport, cell passage, enzyme activity and gene expression, and it is also important in disease resistance, anti-oxidation and drought resistance. Based on assembled sequences of sweet potato (Ipomoea batatas L. Lam) transcriptome, 14-3-3 protein cDNAs were cloned for the first time, and the sequencing analysis revealed the presence of three highly homologous isoforms of 14-3-3 protein cDNAs, designated as Ib14-3-3a, Ib14-3-3b and Ib14-3-3c. Three cDNA isoforms are all 1176 bp in length with 7 mutation sites and have a 789 bp of open reading frame encoding a polypeptide of 262 amino acids. The results from digital gene expression (DGE) profiling showed that the expression levels of 14-3-3 genes are different among tissues, predominantly in harvested tuberous roots (223.08 TPM) and very low in mature leaves (85.07 TPM) , which were also confirmed by semi-quantitative Reverse transcription polymerase chain reaction (RT-PCR) analysis.
 
Details of microbial cultures used in the present investigation.
Article
Bacteriocins are antimicrobials produced mainly by lactic acid bacteria as well other genera, a property which can be exploited in food biopreservation. However, narrow spectrum of activity of these bacteriocins is a limitation for their use in different food systems. Various approaches are being pursued to increase their antimicrobial efficacy like use of increased dosage, use of highly purified form in combination with other preservative techniques such as HPP, ultrasonic waves, use of a combination of bacteriocins, etc. Bacteriocins from two producers namely Lactobacillus plantarum MTCC 1407 and Bacillus coagulans MTCC 492 were used in the present study. Partially purified form of bacteriocin produced by them was tested individually as well as in combination with antimicrobial activity in liquid medium against food spoilage agents, Gram positive organisms such as Streptococcus thermophilus, Leuconostoc mesenteroides, Micrococcus flavus and also Gram negative organisms such as Escherichia coli and Pseudomonas aeruginosa. They were all susceptible to antimicrobial action of these bacteriocins, 26 to 72% inhibition was recorded with turbidometric method of assessment of bacteriocin activity. However, bacteriocins when used in combination of 1:1 (v/v) did not result in increased inhibition.
 
Article
We aimed to delineate the incidence of hepatitis C virus (HCV) infection and HCV seroconversion (SC) in maintenance hemodialysis (HD) patients and to evaluate the effect of isolation measures on HCV in HD unit. From June 1998 to June 2010, 2465 maintenance HD patients in our HD unit were enrolled in, and the anti-HCV ELISA and HCV nucleic acid testing were consecutively performed every six months. The results showed the prevalence rates of HCV antibody detected consecutively every six months were 54.with isolation measures), respectively. HCV SC occurred in 238 patients during the follow-up period. 1077 patients were followed for 1 to 12 months, of which 49 (4.5%) had SC for HCV. The SC rate increased to 75% in 8 patients followed for 139 to 150 months. Taken together, we conclude that the dialysis environment is responsible for transmission of HCV either due to common usage of the machines or to the fact that the HCV positive patients are not isolated. The application of isolated hemodialysis of anti-HCV positive patients plus strict supervised universal infection control techniques significantly effect on the long-term prevalence of HCV antibody and SC in HD patients.
 
Article
We aimed to share the experience of the ISO/IEC 15189:2007 accreditation process in a University Hospital's Medical Microbiology Laboratory before and after the assessment, and tried to seek answers to some questions in applying the standard. Our ISO 15189 accreditation process began in 2008 after having acquired JCI accreditation in 2007. The aim was to be the first accreditated university hospital laboratory in our country. The applied tests in bacteriology, mycology, parasitology, virology, immunology and molecular serology were accreditated. We completed the validation and verification procedures mostly applied to quantitative analyses. Regarding the external quality controls and the internal controls, the corrective actions provided us great control and self correction. We increased the rate of success in the quality controls. We encouraged our laboratory personnel to fill out a laboratory discrepancy form to control our process and to arrange training. During the course of 2009, 60 of the 85 forms were completed in the microbiology laboratory among the central laboratories. Statistical analyses were performed throughout a year and this information helped us in making improvements. The number of training hours in one year was found as 78 h and 30 min during the routine laboratory process. We should provide support in bringing quality to laboratories in our country. As a matter of fact, having our own external quality controls is believed to bring cost effectiveness in acquiring an accreditation process.
 
Article
Although more than 100 serotypes of shigatoxigenic Escherichia coli (STEC) have been implicated in cases of human diseases, E. coli O 157 is the most common serogroup connected with sporadic cases and large outbreaks of diseases in many countries. Rapid and sensitive identification of this dangerous pathogen is important for patient management and for prompt epidemiological investigations. PCR has become a very rapid and reliable tool for the molecular diagnosis of E. coli O 157 . PCR assays are usually aimed at detecting the shiga toxins, the intimin protein and enterohaemolysin. In the present study, a mPCR-based protocol is described as that which uses one primer set to detect the gene responsible for the production of the O-antigen synthesis (rfb O 157) and four primer set to detect the major virulence factor genes including the Shigatoxin type 1 and 2 (stx 1 and stx 2), intimin (eaeA) and enterohemolysin (EHEC hlyA) directly from 190 samples of animal faeces at the time of slaughter after overnight incubation of stool specimens in BPW. In this research, we use one primer set for detection of the gene responsible for the production of the O-antigen synthesis (rfb O 157) and four primer set for detection of the Shigatoxin type 1 and 2 (stx 1 and stx 2), intimin (eaeA) and enterohemolysin (EHEC hlyA) producing genes directly from 190 samples of animal faeces at the time of slaughter after overnight incubation of stool specimens in BPW. This study has established the presence of rather high prevalence of E. coli O 157 -positive animals at abattoirs (These consisted of 4.2% of cattle and 2.1% of sheep), providing an increased risk of transmission of E. coli O 157 to the food chain and contamination of human.
 
Article
Infection with Shiga like toxin-producing strains of Escherichia coli (STEC) in addition to diarrhea is associated with severe and fatal complications such as hemolytic uremia syndrome (HUS). Nonetheless, the conventional diagnostic methods of the strains are not precise, and accurate data regarding their infection incidence is not available in many countries including Iran. The aim of this study was to detect stx(1), stx(2), LT and ST toxin genes, as well as O-157 and H-7 antigen genes in E. coli samples isolated from patients with urinary tract infection. A total of 100 urinary samples were collected from patients with urinary tract infection who were referring to the health centers in Tehran, Iran, during years 2010-2011. E. coli isolation was performed according to the standard laboratory methods. DNA was extracted from samples and the presence of stx(1), stx(2), lt, st, O-157 and H-7 genes was investigated by PCR method. Out of 100 samples, 10 (10%) were carrying stx(1), 7 (7%) H-7, 6 (6%) stx(2), 2 (2%) lt, and 1 (1%) O-157 genes. One sample was carrying both stx(1) and stx(2) genes, while none of samples were carrying st gene. The results indicate that ETEC and STEC strains, with a relatively conserved genetic pool, are capable of causing urinary tract infection. Due to the importance of these strains in public health, it is suggested that the conventional methods used for their detection be replaced by a molecular method especially based on the presence of stx genes.
 
The demographic characteristics of 351 patients.
The studies of hepatitis A seroprevalence conducted in Turkey.
Article
This study aims to determine the seroprevalence of hepatitis A among children aged 1-16 years in eastern region of Turkey. The study was conducted at Tunceli State Hospital in Eastern Anatolia, Turkey. Anti-HAV IgM and Anti-HAV IgG antibodies were evaluated among 351 patients admitted to our pediatric policlinic. Anti-HAV IgM and Anti-HAV IgG serologic markers were determined using the ELISA method. The mean age of 351 pediatric patients was 7.5±4.2; of these, 198 (56.4%) were male and 153 (43.6%) were female. A total of 305 (86.9%) cases in this study were seronegative against hepatitis A. Anti-HAV IgG was positive among 46 (13.1%) patients, of these 22 (47.8%) were male and 24 (52.2%) were female. The mean age of seropositive cases was 8.4±4.8. Anti-HAV IgM seropositivity was not detected in the study. The application of a routine hepatitis A vaccine among children will reduce the potential for the development of severe complications. Key words: Hepatitis A, seroprevalence, children, vaccination.
 
Article
The purpose of the study was to evaluate the antagonistic activity of probiotics isolated from products to germination of Candida albicans in vitro. The spent culture supernatant, live bacteria, heat-killed bacteria of 16 strains of probiotics and main bacterial short-chain fatty acids were applied to inhibit the germination of C. albicans in vitro by crystal violet-based germ tube assay. Neutral SCS of all the probiotcis evaluated in this research could decrease germination significantly and live bacteria of Lactobacillus rhamnosus LGG, Lactobacillus plantarum LA, Lactobacillus johnsonii JCM1022, Bacillus Longum-2, Bacillus sub. and Bacillus lich could partially inhibit the conversion of yeast to germ. However, all the heat-killed bacteria failed to control the germ tube formation. Furthermore, only butyric acid blocked the conversion of yeast to hypha among all the SCFAs. These results suggest that L. rhamnosus LGG, L. plantarum LA and L. johnsonii JCM1022, B.Longum-2, Bacillus sub. and B. lich maybe potential strains to use as antifungal drugs and the inhibition seems to have direct correlation to the metabolites butyric acid.
 
Genetic typing of 5' -UTR nucleotide sequences. SD-111, XZ-134, XZ-129, YZ-6, YZ-20, YZ-13, YZ-18, WX-49, ZZ-75, YZ-19, ZZ-74, YZ-7, ZZ-73, WX-50, SD-126, XZ-132 were the strains isolated in this survey.  
Article
Eighty calf blood samples were collected from different areas of China and were examined. Sixteen non cytopathic isolates of bovine viral diarrhea virus genotype 2 (BVDV-2) were isolated by specific BVDV-2- directed RT-PCR and sandwich enzyme-linked immunosorbent assay (ELISA). The results were verified by the indirect immunofluorescence assay and the ultra-thin sections. Genes of 5'-UTR, E2 and Npro from all the 16 field isolates were sequenced. The sequence identities at the nucleotide and amino acid levels were higher than 99.0%. The phylogenetic analysis revealed that the BVDV-2 USA strain, AzSpin, had the highest sequence homology with each of the Chinese isolates.
 
Article
Accepted 10 May, 2013 Haloarchaea such as Halorubrum are excellent models for field and laboratory study. Almost half of the new species of Halorubrum were identified from the samples collected from China. The aim of this study is to determine whether some species reported elsewhere are distributed in China. Hypersaline environments-a special niche, are distributed all over the world. The genus Halorubrum frequently dominates the microbial communities in hypersaline environment. We collected tens of salt mine or saline soil samples from China’s Yunnan, Hainan and Jiangsu provinces (China) for Halorubrum isolation. Tens of haloarchaea strains with different morphological properties were isolated. The 16S rRNA genes were amplified by using Halorubrum specific primers and cloned into the vector for sequencing. The raw classifications were based on the phylogenetic analyses, and the results showed that 29 strains were affiliated with genus Halorubrum and isolated 29 strains of haloarchaea affiliated with Halorubrum. The 16S rRNA gene sequences were amplified by Halorubrum specific primers. Additional sequences available in GenBank were downloaded. Phylogenetic analyses of 16S rRNA gene sequences revealed: 1) Nineteen lineages, of which eleven shared a low sequence similarity (less than 99%) with the validly described species and, thus, may represent new taxa; 2) new records of five known species also distributed in China; 3) at least two separated lineages may represent new species. This is the first report of such high species diversity of Halorubrum in China. Key word: Halorubrum, rRNA gene sequences, hypersaline, haloarchaea strains.
 
Article
16S rRNA methylase-mediated high-level resistance to aminoglycosides has been reported recently in clinical isolates of Gram-negative bacilli from several countries. Five (2.5%, 5/198) of 198 isolates of Proteus mirabilis from a teaching hospital in Wenzhou, China, were positive for 16S rRNA methylase genes (one for armA, four for rmtB) and highly resistant to gentamicin, amikacin and tobramycin (MICs, 256 g/ml). One of five isolates harboring 16S rRNA methyalse genes were extended-spectrum -lactamases (ESBL) producer. The plasmids harboring 16S rRNA methylase genes from four out of five donors were transferred into the recipients, Escherichia coli J53. Among five isolates harboring armA and rmtB, the armA gene and the rmtB genes were located on the plasmids, as determined by Southern hybridization. The present study investigated the prevalence of 16S rRNA methylase genes in clinical isolates of P. mirabilis in China for the first time.
 
Top-cited authors
Sumitra Chanda
  • Saurashtra University
James Doughari Hamuel
  • Modibbo Adama University of Technology, Adama
Raj Dave
  • Food Testing Laboratory
Pegah Chehrazi
  • Université de Montréal
Zarrindokht Emami-Karvani
  • Islamic Azad University Falavarjan Branch