Diarrheagenic Escherichia coli with Multidrug Resistance in Cattle from Mexico

Mexico is an important producer/exporter of cattle and cattle products. In the last decade, an increase in antibiotic resistance in E. coli pathotype strains from livestock environments has been reported. This study aimed to determine the prevalence and antibiotic resistance profiles of E. coli pathotype strains from the feces of beef or dairy cattle reared in the states of Aguascalientes (AG, central) and Nuevo Leon (NL, northeastern) in Mexico. One hundred and ten fecal samples were collected (beef cattle-AG = 30; dairy cattle-AG = 20; beef cattle-NL = 30; dairy cattle-NL = 30). From these, E. coli was isolated using selective/differential media and confirmed on chromogenic media. Multiplex PCR was used to identify diarrheagenic E. coli, and the Kirby-Bauer technique was used to determine the antimicrobial susceptibilities. All the animals harbored E. coli, and pathotypes were found in 34 animals from both, beef and dairy cattle, mainly from Aguascalientes. Of the positive samples, 31 harbored a single E. coli pathotype, whereas three samples harbored two different pathotypes; EHEC was the most prevalent, followed by EPEC, ETEC, and EIEC or the combination of two of them in some samples. Most pathotype strains (19/37) were isolated from beef cattle. Neither the animals' productive purpose (beef or dairy cattle) (r = 0.155) nor the geographic regions (Aguascalientes or Nuevo Leon) (r = -0.066) had a strong positive correlation with the number of E. coli pathotype strains. However, animals reared in Aguascalientes had up to 8.5-fold higher risk of harboring E. coli pathotype strains than those reared in Nuevo Leon. All pathotype strains were resistant to erythromycin, tetracycline, and trimethoprim/sulfamethoxazole, and all dairy cattle pathotype strains were further resistant to five β-lactams (χ2, P = 0.017). The existence of these pathotypes and multidrug-resistant pathogens in the food chain is a risk to public health.

Comparative prevalence of diarrheagenic Escherichia coli between children below five years with close contact to food animals in Kisumu County, Kenya

Introduction

diarrheal infections in young children below five years and food animals are caused by diarrheagenic Escherichia coli strains. The study focused on understanding the association between DEC pathotypes in children below five years and food animals to establish the possibility of zoonotic transmission.

Methods

samples from 150 children who presented with diarrhea at the Kisumu County Hospital and 100 stool samples from food animals were collected and processed using culture methods. Molecular identification of the pathotypes was assayed using a primer-specific polymerase chain reaction that targeted the six virulence genes related to the diarrheagenic Escherichia coli pathotypes.

Results

one hundred and fifty-six study subjects (100 children samples and 56 food animals) samples were positive for E. coli polymerase chain reaction detection revealed a prevalence of (23%) among children below five years and a prevalence of (20%) among the food animals. Children samples showed Enteroaggregative Escherichia coli, having high phenotypic frequency of (12%) followed by Enterotoxigenic Escherichia coli, (5.3%) and Enteropathogenic Escherichia (3.3%) the least being mixed infections Enteroaggregative/Enterotoxigenic Escherichia coli and Enteroaggregative/Enteropathogenic Escherichia coli with (1.3%) respectively. The food animals found in children homesteads were detected to harbor pathogenic strains of E. coli. Enteropathogenic Escherichia coli was the most prevalent pathotypes detected in cattle (13%) followed by Enterotoxigenic Escherichia coli detected in goats at (4%) and poultry at (3%).

Conclusion

presence of diarrheagenic Escherichia coli in food animals could serve as reservoirs of transmitting these bacteria to children below five years.

Antimicrobial resistance and prevalence of diarrheagenic Escherichia coli (DEC), in diarrheic yaks of Tibetan Plateau, China

This study was conducted to test the distribution of diarrheagenic Escherichia coli (DEC) associated genes in fecal isolates from diarrheic yaks of a high remote region of China. Briefly, we obtained 203 fecal samples from diarrheic adult yaks and E. coli strains were isolated and identified via standard methods The antibiotic sensitivity of isolates was determined via disk diffusion method and polymerase chain reaction (PCR) was used to detect the DEC virulence associated genes. Results of the current study showed a high rate of resistance to tetracycline (93.6%) and low rate of resistance to ofloxacin (16.7%) antibiotics. Meanwhile, five different diarrheagenic associated virulence traits were detected including; EAEC (11.80%), EHEC (25.62%), EIEC (17.18%), EPEC (36.92%) and ETEC (11.36%). Moreover, E. coli isolates were positive for all tested DEC associated virulence genes ranging from 1.48% to 33%. Additionally, four isolates were positive for more than one virulence genes. In conclusion, our investigation showed a relatively low number of E. coli virulence genes isolated from diarrheic Tibetan yaks, which could be attributed to the high altitude induced harsh environmental conditions that may not help in the growth and survival of pathogenic organisms. In addition, this study highlights the high level of antibiotic resistance in yaks, therefore; preventive measures should be taken to monitor the antibiotic usage in Tibet region of China.

Design of an improved multiplex PCR method for diagnosis of enterohaemoraghic E.coli and enteropathogic E.coli pathotypes

AIM

We aimed to develop a multiplex PCR assay for specific detection of EPEC and EHEC pathotypes based on specific marker genes.

BACKGROUND

About 2.5 million infant's morbidity in developing countries occurs by E.coli pathotypes because of diarrhea and intestinal diseases. The traditional phenotypic methods are time consuming and sometimes detection and differentiation of the pathotypes are not done easily. Multiplex PCR technology is used as a sensitive, specific and rapid molecular method for detection of various pathogens.

PATIENTS AND METHODS

PCR reactions were performed with primers which targeted the virulence genes selected for each category (stx 1 , stx 2 genes for EHEC and bfpA for EPEC). For preparation of a positive control, the PCR products were cloned in pTZ57R/T plasmid. The same PCR reactions were done but in presence of genomes of various negative control bacteria for evaluation of test specificity.

RESULTS

As expected, gel agarose electrophoresis of PCR products of the stx 1 , stx 2 and bfpA, showed 329bp, 586bp and459bp bands respectively. Result of amplification using negative control genomes as template was negative.

CONCLUSION

The multiplex PCR assay followed by capillary electrophoresis presented in the present paper provides a simple, reliable, and rapid procedure that in a single reaction identifies the four main pathotypes of E. coli. This assay will replace the previous molecular genetics methods used in our laboratory and work as an important supplement to the more time consuming phenotypic assays.