SEROTYPES, TOXINS AND ANTIBIOTIC RESISTANCE OF Escherichia coli (E.COLI) STRAINS ISOLATED FROM DIARRHEIC RABBITS IN PHU VANG, THUA THIEN HUE

This study was conducted to determine the prevalence of E. coli in rabbits, their biochemical and serological characteristics, common virulence genes, and antibiotic resistance. The diarrhea rabbit feces were collected from households and rabbit farms in Phu Vang - Thua Thien Hue with a total of 250 samples for testing. The results showed that rabbits age from 31 to 45 days old had the highest incidence of diarrhea disease caused by E.coli (92.0%) and the lowest infection rate was observed in rabbits over 60 days old with an infection rate of 30%. Further, the isolated E.coli strains tested biochemical characteristics showed 100% motile, positive for indole and methyl red, fermenting glucose and lactose. Simultaneously these strains were detected belong to 7 serotypes O103, O157, O158, O169, O44, O125, O153 and susceptible to cefuroxime (95.45%), akamicin (86.37%), streptomycin (81.82%), amoxicillin (81.82%), tetracycline (68.18%), colistin (68.18%), ampicillin (63.63%), gentamycin (59.10%) and levofloxacin (50.0%), whilst resistant to doxycycline (100%), sulfamethoxazole-bactrim (95.46%), and neomycin (86.37%). By using PCR assay for detection of virulence genes of the isolated E. coli strains, there were 7 strains carried virulence genes, of which 4/7 E. coli strains carried eaeA and tsh genes (57.14%), 2/7 strains carried stx2 gene (28.57%); 1/7 E. coli strains carried stx1 gene (14.28%) and the F4, F5 and F6 genes were not found in all serotypes in this study.

Detection of aerobic bacterial pathogens associated with early embryonic death in pregnant New Zealand female Rabbits in Egypt

Background and Aim: Rabbits are a highly sensitive species and susceptible to various bacterial pathogens that may be causative agents for early embryonic death. This study aimed to explore the administration of different bacterial agents in does suffering from early embryonic death. Furthermore, identification of genes associated with virulence was performed to identify the phenotypic and genotypic antimicrobial resistance patterns that may increase the virulence of pathogens and lead to early embryonic death. Materials and Methods: We isolated and identified bacterial agents in 106 samples from live and dead female rabbits that had undergone early embryonic death, including liver and intestine tissue, aborted fetuses, discharges, and vaginal swabs. Conventional polymerase chain reaction (PCR) was conducted to confirm the identity of the isolated bacterial strains and their virulence. Moreover, antibiotic resistance was studied phenotypically and genotypically. Results: We isolated Escherichia coli, Salmonella, Staphylococcus aureus, Pasteurella multocida, and Listeria monocytogenes. PCR confirmed typical identification except in P. multocida, which was confirmed as Gallibacterium spp. in some cases. The final percentage of detection was 34%, 30.2%, 16.9%, 13.2%, and 11.3%, respectively. Virulence properties were investigated using different designated genes. All Salmonella strains harbored invA, stn, avrA, and ompf genes, while the sopE gene was identified in 31.25%. E. coli strains harboring the iss gene lacked the shiga toxin (stx1) gene. L. monocytogenes and S. aureus strains harbored the hemolysin gene (66.7% and 33.4%, respectively). Multidrug resistance was detected phenotypically and genotypically in most strains. Each bacterial pathogen had a different antibiotic resistance profile. Conclusion: Multiple bacterial species may contribute to early embryonic death in does. Furthermore, the combined infection could be the main cause of early embryonic death. Thus, monitoring programs should bear this in mind and focus on the early detection of these bacterial agents in female rabbits to avoid embryonic death.

Studies of Virulence Factors of Avian Pathogenic Escherichia coli in Avian Colibacillosis by In vitro Method and PCR

Background: Avian colibacillosis is considered as major cause of morbidity and mortality in poultry. It is a common bacterial disease of poultry and many virulence factors of E. coli are associated with the disease. The current study was aimed to investigate the presence of some virulence factors of E. coli isolated from the cases of colibacillosis.Methods: In present study, total 150 samples (liver, heart, lungs, air sacs and feaces) of chicken exhibiting pathological conditions of colibacillosis were collected from various poultry farms (organized and backyard) situated in and around Mhow and Indore cities. E.coli was isolated and identified from the samples on the basis of cultural characteristics and biochemical test. All E. coli isolates were further subjected to evaluate the presence of virulence factors such as biofilm production, haemolysis, invasiveness and molecular detection of fimH and stx1 gene.Result: Out of these 51.33% of incidence of E. coli was recorded. E. coli O84 and O149 serotypes were found most prevalent. Out of 77 isolates, 46 (59.7%) and 45 (58.4%) were positive for biofilm formation by tube method and modified CRA method, respectively. All E. coli isolates were showing invasiveness in congo red binding assay while none of the isolates was found haemolytic. Molecular detection revealed the presence of fimH (508bp) gene in 33.3% of tested samples while stx1 gene could not be detected in any isolates.

Effects of Plant Age and Root Damage on Internalization of Shiga Toxin-Producing Escherichia coli in Leafy Vegetables and Herbs

Our previous study reported that fresh produce grown in aquaponic and hydroponic systems can pose potential food safety hazards due to an accidental introduction of contaminated fish and cross-contamination between the systems. In this study, we examined the effects of plant species and age on the likelihood and level of internalization of Shiga toxin-producing Escherichia coli (STEC) in aquaponic and hydroponic systems. Four plant species, basil (Ocimum basilicum L. cv. Genovese), cilantro (Coriandrum Sativum L.), lettuce (Lactuca sativa cv. Cherokee), and kale (Brassica oleracea var. sabellica), received root damage treatment as seedlings before transplanting or mature plants at three weeks after transplanting by cutting off 1-cm tips of one-third of the roots. Enrichments and selective media were used for the isolation, and presumptive positive colonies were confirmed by PCR for the presence of stx1 gene in plant tissues, recirculating water, and fish feces collected at four weeks after transplanting. In hydroponic systems, STEC was found neither in the solution nor in the roots and leaves of all four plant species, possibly through improved sanitation and hygiene practices. However, consistent with our previous findings, STEC was found in the water, on the plant roots, and in the fish feces in aquaponic systems, even after thorough sanitation prior to the study. Regardless of plant age, STEC was internalized in the roots of all plant species when the roots were damaged, but there was no difference in the degree of internalization with STEC among plant species. STEC was present in the leaves only when seedlings received root damage treatment and were grown to maturity, indicating that root damage allows STEC to internalize in the roots within a week, but a longer period is required for STEC to internalize into the leaves. We concluded that root damage on seedlings can cause the internalization of E. coli O157:H7 in the edible parts of leafy vegetables and herbs in soilless production systems.

Comparison of UV, Peracetic Acid and Sodium Hypochlorite Treatment in the Disinfection of Urban Wastewater

One source of water contamination is the release of wastewater that has not undergone efficient treatment. The aim of this study was to evaluate the reduction obtained with sodium hypochlorite (NaClO), UV and peracetic acid disinfection treatment of Salmonella spp., pathogenic Campylobacter, STEC and bacterial indicators in three full-scale municipal wastewater plants. A general reduction in Salmonella was observed after disinfection, but these bacteria were detected in one UV-treated sample (culture method) and in 33%, 50% and 17% of samples collected after NaClO, UV and PAA disinfection treatments, respectively (PCR method). A better reduction was also observed under NaClO disinfection for the microbial indicators. Independent of the disinfection treatment, E. coli O157:H7 was not detected in the disinfected samples, whereas some samples treated with UV and PAA showed the presence of the stx1 gene. No reduction in the presence of stx2 genes was verified for any of the disinfection treatments. Campylobacter was not detected in any of the analysed samples. The overall results highlight a better reduction in microbiological parameters with a NaClO disinfection treatment in a full-scale municipal wastewater plant compared with UV and PAA. However, the results indicate that a complete and specific monitoring program is necessary to prevent a possible risk to public health.

The Prevalence of Shiga toxin-1 in non-Shigella dysenteriae isolates collected from diarrhea samples in patients, Ahvaz, Iran

Background: Acute diarrhea is a major public health problem particularly in developing countries. Shigellosis is one of the substantial causative agents of microbial dysentery and still has a remarkable prevalence particularly in areas with poor hygienic infrastructures. The probable existence of the deadly Shiga toxin (Stx) protein in some Shigella strains would manifest life-threatening clinical symptoms of the infection. Methods: The aim of this study was to determine the presence of Shigella toxin 1 (Stx1) in isolated from patients with diarrhea. Totally, 227 Shigella species including 60 S. flexneri, 157 S. sonnei, and 10 S. boydii were collected from diarrheal patients in tropical infectious diseases research center of Ahvaz, Iran, during 2013-2015. The isolates were collected mostly from the intensive care unit, infectious disease, and surgery settings. The isolates were identified and the polymerase chain reaction (PCR) was performed to detect the stx gene. Results: The results indicated that none of them encode the stx1 gene. Conclusion: Isolates of this study were not capable of stx1 encoding. Future investigations should consider the relations between other Shigella species and Shigella toxin in Iran.

Molecular profiling and antimicrobial susceptibility of Escherichia coli O157:H7 isolated in Bulgaria

The purpose of this study was to detect the presence of shiga-toxin producing Escherichia coli (STEC) in faeces of healthy dairy cattle and to determine the sensitivity of isolates to several anti­microbial drugs. A total of 1,104 anal swab samples originating from 28 cattle farms were examined. After the primary identification, 30 strains were found to belong to serogroup О157. By means of conventional multiplex PCR, isolates were screened for presence of resistance genes stx1, stx2 and eaeА. Twenty-nine strains possesses amplicons with a size corresponding to genes stx2 and eaeA, one had amplicons also for the stx1 gene and one lacked amplicons of all three genes. Twenty-eight strains demonstrated amplicons equivalent to gene H7. The results from phenotype analysis of resistance showed preserved sensitivity to ceftriaxone, ceftazidime, cefotaxime, cephalothin, streptomycin, gentamicin, tetracycline, enrofloxacin and combinations sulfamethoxazole/trimethoprim and amoxicillin/clavulanic acid. Sensitivity to ampicillin was relatively preserved, although at a lower extent.

Escherichia coli O157:H7 in Drin Prevalence of Escherichia coli O157:H7 in Drink from Different Food Premises in Kota Samarahan Sarawak

Contamination of drinks with E. coli O157:H7 served in food premises such as restaurants can cause haemorrhagic colitis and haemolytic uremic syndrome to humans. The presence or absence of faecal pathogen was demonstrated using coliform group as indicator microorganisms. Therefore, this study was conducted to detect the presence of E. coli O157:H7 in drinking water from food restaurant premise in Kota Samarahan and Kuching to ensure safe and potable drinking water is served to the consumer. A total of thirty (n=30) drink samples including six types of each of the samples are cold plain water, iced tea, iced milo, syrup and iced milk tea. Most Probable Number (MPN) procedure was used in this study to enumerate the MPN values of coliform bacteria in each drink collected. A total of 53.33% (16/30) of the drink samples showed positive E. coli detection. Then, the PCR assay showed 6.25% (one out of 16 isolates) samples were positive and carried stx1 gene produced by E. coli O157:H7 in iced milo sample types. This study showed the drinks collected from food premises was contaminated with faecal contamination, which was not safe to drink by the consumer. Therefore, preventive actions should be taken to prevent foodborne illness outbreak in future

Isolation, genotyping and antimicrobial susceptibility of pathogenic Escherichia coli serotypes in ready to eat foods

In this study, pathogenic Escherichia coli serotypes (E. coli O157:H7, O26, O111) and their molecular proximity and antimicrobial susceptibility were investigated in RTE foods. A total of 240 samples; consist of 105 stuffed mussel, 56 meatless cig kofte, 54 Russian salad, 25 cheese halva, were analyzed. The conventional culture and serotyping methods for determination of the organisms were performed and further confirmation by PCR was carried out. Confirmed E. coli O157 isolates were genotyped by the enterobacterial repetitive intergenic consensus(ERIC)-PCR. Antibacterial susceptibility testing of the isolates was performed by disc diffusion method. E. coli was detected in 7 (2.9 %) of 240 samples, including 3 (5.5%) Russian salad, 3 (2.8%) stuffed mussel, 1 (4 %) cheese halva. Two isolates from Russian salad, 1 from stuffed mussel and 1 from cheese halva were identified as E. coli O157 . In addition, stuffed mussel isolate was found to carry stx1 ve hlyA genes whereas one Russian salad isolate carried the stx1 gene. E. coli isolates were found to be resistant to amoxycillin/clavulonic acid, gentamicin and ciprofloxacin, at the rate of 29%, 14% and 29 %, respectively. Only one (14 %) isolate from stuffed mussel was classified as multidrug resistant to three antimicrobials. Furthermore, the isolates, related to O157 and O157:H7, presented different ribotypes in this study. The results provide useful data for the development of public health policy concerning the potential presence of pathogenic antimicrobial resistant E. coli serotypes in RTE foods. Strict surveillance of RTE foods at retail points for emerging pathogens, their antimicrobial resistance patterns and the potential likelihood of cross-contamination is required.

Distribution of the stx1 and stx2 genes in Escherichia coli isolated from milk cattle according to season, age, and production scale in southwestern region of Goiás, Brazil

ABSTRACT This study determined the distribution of stx1 and stx2 genes in Escherichia coli isolated from dairy herds with regard to animal age, season, and farm production-scale, and analyzed the phylogenetic distribution of the groups A, B1, B2, and D of 276 isolates of bovine feces Shiga toxin-producing E. coli (STEC). The stx1 profile was the most common, detected in 20.4% (202/990) of the isolates, followed by stx2 (4.54%, 45/990) and stx1+stx2 (2.92%, 29/990). The stx1 gene was detected more frequently in calves than in adult animals. In the dry season (winter), the presence of stx1+stx2 profile in cattle feces was higher than in the rainy season (summer), while no significant changes were observed between seasons for the stx1 and stx2 profiles. The most predominant phylogenetic groups in adult animals were B1, A, and D, while groups A and B1 prevailed in calves. Our data highlight the importance of identifying STEC reservoirs, since 7.5% of the tested isolates were positive for stx2, the main profile responsible for the hemolytic-uremic syndrome (HUS). Moreover, these microorganisms are adapted to survive even in hostile environments and can contaminate the food production chain, posing a significant risk to consumers of animal products.