Abstract
BackgroundAntimicrobial resistance (AMR) is an increasing global health concern reducing options for therapy of infections and also for perioperative prophylaxis. Many Enterobacteriaceae cannot be treated anymore with third generation cephalosporins (3GC) due to the production of certain 3GC hydrolysing enzymes (extended spectrum beta-lactamases, ESBLs). The role of animals as carriers and vectors of multi-resistant bacteria in different geographical regions is poorly understood. Therefore, we investigated the occurrence and molecular characteristics of ESBL-producing Escherichia coli (E. coli) in wild birds and slaughtered cattle in Ibadan, Nigeria.Cattle faecal samples (n = 250) and wild bird pooled faecal samples (cattle egrets, Bubulcus ibis, n = 28; white-faced whistling duck, Dendrocygna viduata, n = 24) were collected and cultured on cefotaxime-eosin methylene blue agar. Antimicrobial susceptibility was determined by agar diffusion assays and all 3GC resistant isolates were genotypically characterised for AMR genes, virulence associated genes (VAGs) and serotypes using DNA microarray-based assays.ResultsAll 3GC resistant isolates were E. coli: cattle (n = 53), egrets (n = 87) and whistling duck (n = 4); cultured from 32/250 (12.8%), 26/28 (92.9%), 2/24(8.3%), cattle, egrets and whistling duck faecal samples, respectively. blaCTX-M gene family was prevalent; blaCTX-M15 (83.3%) predominated over blaCTX-M9 (11.8%). All were susceptible to carbapenems. The majority of isolates were resistant to at least one of the other tested antimicrobials; multidrug resistance was highest in the isolates recovered from egrets.The isolates harboured diverse repositories of other AMR genes (including strB and sul2), integrons (predominantly class 1) and VAGs. The isolates recovered from egrets harboured more AMR genes; eight were unique to these isolates including tetG, gepA, and floR. The prevalent VAGs included hemL and iss; while 14 (including sepA) were unique to certain animal isolates. E. coli serotypes O9:H9, O9:H30 and O9:H4 predominated. An identical phenotypic microarray profile was detected in three isolates from egrets and cattle, indicative of a clonal relationship amongst these isolates.ConclusionWild birds and cattle harbour diverse ESBL-producing E. coli populations with potential of inter-species dissemination and virulence. Recommended guidelines to balance public health and habitat conservation should be implemented with continuous surveillance.
Highlights
Antimicrobial resistance (AMR) is an increasing global health concern reducing options for therapy of infections and for perioperative prophylaxis
Of particular concern are extendedspectrum β-lactamase (ESBL)-producing bacteria which are resistant to third generation cephalosporins (3GC) through hydrolysis of these antimicrobials [4, 5] and which pose especially serious treatment challenges [6]
From the cefotaxime-eosin methylene blue agar (CEMB) plates, 88, 4 and 55 putative E. coli isolates were picked for further analysis; in addition to one unassigned bacterial isolate each from egret and cattle faecal samples
Summary
Antimicrobial resistance (AMR) is an increasing global health concern reducing options for therapy of infections and for perioperative prophylaxis. Antimicrobial resistance (AMR) in bacteria is an increasing and widespread public health concern which has grossly eroded the efficacy of many antimicrobial substances. Of particular concern are extendedspectrum β-lactamase (ESBL)-producing bacteria which are resistant to third generation cephalosporins (3GC) through hydrolysis of these antimicrobials [4, 5] and which pose especially serious treatment challenges [6]. ESBL genes of the CTX-M family are the most common with blaCTX-M-1/15 being most prevalent [9]. The family Enterobacteriaceae, E. coli, are common ESBL-producers. They inhabit animal and human guts and could cause diverse infections [8, 11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
