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

Abstract

BackgroundAntimicrobial resistance in Shiga toxin-producing Escherichia coli (STEC) O157 and non-O157 is a matter of increasing concern. The aim of the present study was to investigate the antimicrobial resistance profiles of STEC O157 and non-O157 recovered from feces of domestic farm animals in the agricultural Culiacan Valley in Northwestern Mexico.FindingsAll of the examined STEC strains showed susceptibility to five antimicrobials, ceftazidime, ceftriaxone, ciprofloxacin, nalidixic acid, and trimethoprim-sulfamethoxazole. However, resistance to the four antimicrobials, ampicillin, cephalothin, chloramphenicol, and kanamycin was commonly observed. Interestingly, non-susceptibility to cephalothin was predominant among the examined STEC strains, corresponding to 85 % (22/26) of the O157:H7 from cattle, sheep and chicken and 73 % (24/33) of the non-O157 strains from cattle and sheep. Statistical analyses revealed that resistance to ampicillin was significantly correlated to 38 % (10/26) of STEC O157:H7 strains from multiple animal sources. Another significant correlation was found between serotype, source, and antimicrobial resistance; all of the O20:H4 strains, recovered from sheep, were highly resistant to tetracycline. Multidrug resistance profiles were identified in 42 % (22/53) of the non-susceptible STEC strains with clinically-relevant serotypes O8:H9, O75:H8, O146:H21, and O157:H7.ConclusionsSTEC O157 and non-O157 strains, recovered from domestic farm animals in the Culiacan Valley, exhibited resistance to classes of antimicrobials commonly used in Mexico, such as aminoglycosides, tetracyclines, cephalosporins and penicillin but were susceptible to fluoroquinolones, quinolones, and sulfonamides. These findings provide fundamental information that would aid in the surveillance of antimicrobial resistance in an important agricultural region in Northwestern Mexico.Electronic supplementary materialThe online version of this article (doi:10.1186/s13756-015-0100-5) contains supplementary material, which is available to authorized users.

Prevalence and Antibiotic Resistance of <i>Escherichia coli</i> O157:H7 Isolated from Raw Meat Samples of Ruminants and Poultry

“…Twenty-five grams of each meat sample was aseptically transferred to 225 ml of Trypticase Soy Broth (TSB, Merck, Frankfurt, Germany) supplemented with 0.5 mg/ml novobiocin and incubated at 37°C for 24 hrs [10,16]. Enriched culture was plated onto Sorbitol MacConkey agar (SMAC, Merck, Frankfurt, Germany) supplemented with cefixime (0.05 mg/ml) and potassium tellurite (2.5 mg/L).…”

“…Then, non-sorbitol fermented colonies were selected from the SMAC plates and streaked onto plates containing Eosin Methylene Blue agar (EMB, Merck, Frankfurt, Germany) and were incubated at 37°C for 24 hrs. These isolates, with typical E. coli green metallic shine on EMB agar were biochemically tested for growth on triple sugar iron agar (TSI, Merck, Frankfurt, Germany) and lysine iron agar (LIA, Merck, Frankfurt, Germany), oxidative/fermentative degradation of glucose, citrate utilization, urease production, indole production, tryptophan degradation, glucose degradation (methyl red test, Merck, Frankfurt, Germany), Voges Proskauer (VP, Merck, Frankfurt, Germany), lysine decarboxylase and motility tests [10,16].…”

“…Food samples with animal origin and especially meat have been found to harbor E. coli 0157:H7 with high levels of resistance against commonly used groups of antibiotics including quinolones, aminoglycosides, macrolides, cephalosporins, sulfonamides, fluoroquinolones and tetracycline [9][10][11][12][13][14][15]. Some antibiotic resistance genes including the genes that encode resistance to ampicillin (CITM), fluoroquinolone (qnr), gentamicin (aac(3)-IV), cephalothin (blaSHV), trimethoprim (dfrA1), sulfonamide (sul1), tetracycline (tetA and tetB), chloramphenicol (cat1 and cmlA) and aminoglycosides (aadA1 have been found to be responsible for antibiotic resistance in STEC strains [9][10][11][12][13][14]16,17,18].…”

Characterization of Diarrheagenic Escherichia Coli Serotypes Isolated from Poultry and Humans

“…Other researchers have reported the detection of VTEC from animal sources, for example, in Côte d'Ivoire only one isolate of E.coli was determined to be a STEC strain [31] while Amézquita-Lópe et al [32] reported isolating STEC strains from cattle, chickens and sheep. However, isolates of E. coli from chickens have been reported to be negative for STEC strains in Greece [33] and the USA [34].…”

“…However, the only inference that can be made on VTEC-positive (by VCA) and verotoxin gene-positive to classify them as STEC strains because they were not serotyped specifically for O157 strains, which is a limitation of the current study. It is known that both O157 and non-O157 STEC strains exist that are VTEC [32].…”