Antimicrobial resistance profiles of Shiga toxin-producing Escherichia coli O157 and Non-O157 recovered from domestic farm animals in rural communities in Northwestern Mexico

This study investigates a sorbitol-fermenting enterohaemorrhagic Escherichia coli (SF EHEC) O157 infection in a farmer's family in the Austrian province of Salzburg. The investigation commenced after a 10-month-old boy was admitted to hospital with the clinical diagnosis of a haemolytic–uraemic syndrome (HUS) and his stool specimen grew SF EHEC O157:H−. In a subsequent environmental survey, a stool specimen of the 2-year-old brother and faecal samples of two cattle from the family's farm were also found to be positive for SF EHEC O157:H−. All four isolates had indistinguishable phenotypic and molecular characteristics and were identical to the first strain detected in Bavaria in 1988. Despite identical isolates being demonstrated in Bavaria after 1988, and until this report, increased surveillance in neighbouring Austria had not found this organism. We propose that the strain may have recently spread from Bavaria to Austria. Although SF EHEC O157:H− strains are still rare, they may represent a considerable health threat as they can spread from farm animals to humans and between humans.

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Antimicrobial Resistance of Escherichia coli O157 Isolated from Humans, Cattle, Swine, and Food

Applied and Environmental Microbiology ◽

10.1128/aem.68.2.576-581.2002 ◽

2002 ◽

Vol 68 (2) ◽

pp. 576-581 ◽

Cited By ~ 152

Author(s):

Carl M. Schroeder ◽

Cuiwei Zhao ◽

Chitrita DebRoy ◽

Jocelyn Torcolini ◽

Shaohua Zhao ◽

...

Keyword(s):

Escherichia Coli ◽

Antimicrobial Resistance ◽

Shiga Toxin ◽

Driving Force ◽

Latex Agglutination ◽

Escherichia Coli O157 ◽

Production Environment ◽

E Coli ◽

Shiga Toxin Genes ◽

Selection Of

ABSTRACT A total of 361 Escherichia coli O157 isolates, recovered from humans, cattle, swine, and food during the years 1985 to 2000, were examined to better understand the prevalence of antimicrobial resistance among these organisms. Based on broth microdilution results, 220 (61%) of the isolates were susceptible to all 13 antimicrobials tested. Ninety-nine (27%) of the isolates, however, were resistant to tetracycline, 93 (26%) were resistant to sulfamethoxazole, 61 (17%) were resistant to cephalothin, and 48 (13%) were resistant to ampicillin. Highest frequencies of resistance occurred among swine isolates (n = 70), where 52 (74%) were resistant to sulfamethoxazole, 50 (71%) were resistant to tetracycline, 38 (54%) were resistant to cephalothin, and 17 (24%) were resistant to ampicillin. Based on the presence of Shiga toxin genes as determined by PCR, 210 (58%) of the isolates were identified as Shiga toxin-producing E. coli (STEC). Among these, resistance was generally low, yet 21 (10%) were resistant to sulfamethoxazole and 19 (9%) were resistant to tetracycline. Based on latex agglutination, 189 (52%) of the isolates were identified as E. coli O157:H7, among which 19 (10%) were resistant to sulfamethoxazole and 16 (8%) were resistant to tetracycline. The data suggest that selection pressure imposed by the use of tetracycline derivatives, sulfa drugs, cephalosporins, and penicillins, whether therapeutically in human and veterinary medicine or as prophylaxis in the animal production environment, is a key driving force in the selection of antimicrobial resistance in STEC and non-STEC O157.

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