Isolation and identification of diarrheagenic Escherichia coli causing colibacillosis in calf in selective areas of Bangladesh

Surveillance of Escherichia coli in different types of chicken and duck hatcheries: one health outlook

Escherichia coli is an important zoonotic bacterium that significantly impacts one health concept. E. coli is normally detected in the gut of warm-blooded animals, but some serotypes can cause diseases in humans and animals. Moreover, it can continue for a long time in different environments, replicate in water, and survive outside different hosts. In this study, 171 samples collected from 10 different types of poultry hatcheries (automatic, semiautomatic, and manual "traditional" types) were examined for the prevalence of E. coli. PCR was applied to verify the E. coli isolates via 16S rRNA gene-specific primers. From the gathered samples, 62 E. coli isolates were recovered (36.3%). The highest prevalence was met with the manual "traditional" hatcheries (57.1%) with no significance difference (P = 0.243) in the 3 types of hatcheries. The incidence of E. coli varied significantly in different tested avian types and breeds. The prevalence was 35.7% in duck hatcheries and 37% in chicken hatcheries, with significant differences between breeds of both species (P = 0.024 and 0.001, respectively). The identification of zoonotic E. coli serotypes in this study is concerning, highlighting the need for collaborative efforts across various sectors, including social, environmental, and governance, to promote the adoption of the one health principle in the chicken business. Periodical surveillance, biosecurity measures at the hatcheries and farm levels, and boosting the immunity of birds were recommended to limit the risk of E. coli spread from avian sources to humans.

Domestic cats are potential reservoirs of multidrug-resistant human enteropathogenic E. coli strains in Bangladesh

Companion animals serve as our best friends, confidants, and family members. Thus, disease and antibiotic resistance gene transmission in pets and humans must be sought out. The study aimed to identify the common pathogenic Escherichia coli (E.coli) in pet cats and the antibiotic resistance patterns and resistant gene distribution. Samples (n = 210) were collected from different veterinary clinics in Bangladesh's cities of Mymensingh and Dhaka. Pathogenic E. coli was identified using conventional and molecular approaches. The disc diffusion method assessed the resistance profile against 12 antibiotics, and PCR was used to identify the beta-lactam resistance genes. The prevalence of the stx-1 gene was found to be 2.86%, whereas the rfbO157 prevalence was found to be 1.90% in cats. The stx-1 gene (n = 6) was 100% resistant to erythromycin and imipenem, whereas 100% sensitive to chloramphenicol. In turn, the rfbO157 gene (n = 4) exhibited 100% resistance to erythromycin, imipenem, cefixime, and azithromycin. In addtion, we identified genes that exhibit resistance to beta-lactam antibiotics (100% blaTEM, 40% blaCTX-M, 40% blaSHV2). This study found shiga-toxin producing and extended-spectrum beta-lactamase (ESBL) producing E. coli for the first time in pet cats of Bangladesh. Furthermore, the antimicrobial resistance (AMR) profile of the isolated strains refers to the occurrence of multidrug, which concerns cats and their owners. The existence of these genes in non-diarrheic pet animal isolates indicates that domestic pets may serve as a reservoir for human infection. Thus, one health strategy comprising animal and human health sectors, governments, together with stakeholders is needed to confront multidrug-resistant E. coli infections in Bangladesh.

RETRACTED ARTICLE: Molecular detection of pathogenic Escherichia coli strains and their antibiogram associated with risk factors from diarrheic calves in Jimma Ethiopia

Diarrheagenic Escherichia coli are a number of pathogenic E. coli strains that cause diarrheal infection both in animal and human hosts due to their virulence factors. A cross sectional study was conducted between November, 2016 and April, 2017 to isolate and molecularly detect pathogenic E. coli from diarrheic calves to determine the pathogenic strains, antibiogram and associated risk factors in Jimma town. Purposive sampling technique was used to collect 112 fecal samples from diarrheic calves. Conventional culture and biochemical methods were conducted to isolate E. coli isolates. Molecular method was followed to identify virulence factors of pathogenic E. coli strains. Antimicrobial sensitivity patterns of the isolates were tested using the Kirby-Bauer disk diffusion method. A structured questionnaire was also used to collect information from dairy farms and socio-demographic data. The overall isolation rate of E. coli in calves was 51.8% (58/112) (95% CI 42.0-61.0). The occurrence of the bacterium differed significantly by age, colostrum feeding time, amount of milk given per time and navel treatment (P < 0.05). Multivariable analysis revealed that the odds of being infected was significantly highest in calves which fed 1-1.5 L amount of milk per a time (OR 5.38, 95% CI 1.66-17.45, P = 0.005). The overall virulence genes detection rate was 53.5% (95% CI 40.0-67.0). Eleven (19.6%) of eaeA, 6 (10.7%) of Stx1 and 13 (23.2%) of Stx2 genes were detected from calves isolates. Except ciprofloxacillin, all isolates were resistant to at least one drug. Multi drug resistance was recorded in 68.0% (38/56) of calves isolates. Neomycin, 83.3% (25/30), followed by amoxicillin, 53.3% (16/30) were the highest resisted virulence genes. The study demonstrated considerable isolation rate, multiple antimicrobial resistant isolates and high resistant virulent genes in diarrheic calves. It also indicated that the potential importance of calves as source of pathogenic E. coli strains and resistant genes for human diarrhea infection. Improving the hygienic practice of farms and wise use of antimicrobials could help to reduce the occurrence of pathogenic E. coli in farms. Hence, further studies are needed to describe all virulent factors and serotypes associated with the emergence of drug resistant pathogenic E. coli strains in calves.

Molecular characterization of pathogenic Escherichia coli isolated from diarrheic and in-contact cattle and buffalo calves

Escherichia coli field isolates from calves were characterized and categorized into the most significant diarrheagenic pathotypes using polymerase chain reaction (PCR) assays with different specific primers. The used PCR systems were designed to detect sequences representing the group-specific virulence genes encoding fimbriae f5 (K99), Shiga toxins (stx₁ and stx₂), heat-stable enterotoxins (st), heat-labile enterotoxins (lt), intimin (eae), hemolysin (hylA), and EAEC heat-stable enterotoxin (astA). In the present work, a total of 150 E. coli field isolates were recovered from 150 fecal swabs collected from 100 diarrheic and 50 apparently healthy in-contact cattle and buffalo calves under 3 months old. Out of these 150 isolated E. coli, 106 isolates from 77 diarrheic and 29 in-contact calves harbored one or more of the investigated virulence genes. The pathotyping of the isolates could classify them into shigatoxigenic E. coli (STEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), and enteroaggregative E. coli (EAEC) with a 30.7, 2.7, 12.7, and 7.3% distribution, respectively. Meanwhile, the detection rates of f5, stx₁, stx₂, st, lt, eae, hylA, and astA genes were 17.3, 27.3, 6.7, 10, 37.3, 17.7, 9.3, and 20.7%, respectively. These virulence genes were found either single or in different combinations, such as stx/eae, stx/st/f5, eae/st/f5, or st/lt/f5. Four attaching-effacing shigatoxigenic E. coli isolates (AE-STEC) harboring stx/eae were retrieved from diarrheic calves. Although none of the stx-or eae-positive isolates was verified as O157:H7, STEC isolates detected in apparently healthy calves have potential pathogenicity to humans highlighting their zoonotic importance as reservoirs. Atypical combinations of ETEC/STEC and ETEC/EPEC were also detected in percentages of 14.7 and 2.7%, respectively. Most of these atypical combinations were found more in buffalo calves than in cattle calves. While STEC and EPEC isolates were detected more in cattle calves than in buffalo calves, ETEC isolates were the same in the two species. The pathogenic E. coli infection in calves was recorded to be higher in the first weeks of life with the largest numbers of virulence factor-positive isolates detected at the age of 4 weeks. Histopathological examination of five intestinal samples collected from four dead buffalo calves revealed typical attaching and effacing (AE) lesion which was correlated with the presence of intimin encoding virulence gene (eae). Other lesions characterized by hemorrhagic enteritis, shortening and fusion of intestinal villi and desquamation of the lining epithelium of intestinal mucosa had also been detected.

Identification of Escherichia coli from broiler chickens in Jordan, their antimicrobial resistance, gene characterization and the associated risk factors

BACKGROUND

Avian pathogenic Escherichia coli (APEC) is the principle cause of colibacillosis affecting poultry. The main challenge to the poultry industry is antimicrobial resistance and the emergence of multidrug resistant bacteria that threaten the safety of the food chain. Risk factors associated with emergence of antimicrobial resistance among avian pathogenic E. coli were correlated with the inappropriate use of antimicrobials along with inadequate hygienic practices, which encourages the selection pressure of antimicrobial resistant APEC. The aim of this study was to isolate, identify, serogroup and genotype APEC from broilers, assess their antibiotic resistance profile, expressed genes and the associated risk factors.

RESULTS

APEC was isolated from the visceral organs of sick chickens with a prevalence of 53.4%. The most prevalent serotypes were O1, O2, O25 and O78, in percentage of 14.8, 12.6, 4.4 and 23.7%, respectively. Virulence Associated Genes; SitA, iss, iucD, iucC, astA, tsh cvi and irp2 were detected in rate of 97.4, 93.3, 75, 74, 71, 46.5, 39 and 34%, respectively and 186 (69.2%) isolates possess > 5-10 genes. The highest resistance was found against sulphamethoxazole-trimethoprim, florfenicol, amoxicillin, doxycycline and spectinomycin in percentage; 95.5, 93.7, 93.3, 92.2 and 92.2%, respectively. Sixty-eight percent of APEC isolates were found to have at least 5 out of 8 antimicrobial resistant genes. The most predominant genes were Int1 97%, tetA 78.4%, bla TEM 72.9%, Sul1 72.4%, Sul2 70.2%. Two risk factors were found to be associated with the presence of multi-drug resistant APEC in broiler chickens, with a P value ≤0.05; the use of ground water as source of drinking water and farms located in proximity to other farms.

CONCLUSIONS

This study characterized the VAGs of avian pathogenic E. coli and establish their antimicrobial resistance patterns. The widespread of antimicrobial resistance of APEC isolates and detection of ARGs highlighted the need to monitor the spread of ARGs in poultry farms and the environment in Jordan. Use of ground water and closely located farms were significant risk factors associated with the presence of MDR APEC in broiler chickens in Jordan.