Antimicrobial Drug–Resistant Escherichia coli in Wild Birds and Free-range Poultry, Bangladesh

Badrul Hasan

, Linus Sandegren, Åsa Melhus, Mirva Drobni, Jorge Hernandez, Jonas Waldenström, Munirul Alam, and Björn Olsen

Author affiliations: Author affiliations: Uppsala University Department of Medical SciencesUppsala, Sweden (B. Hasan, Å. Melhus, M. Drobni, B. Olsen); Linnaeus University Centre for Ecology and Epidemiology in Microbial Model Systems, Kalmar, Sweden (B. Hasan, J. Hernandez, J. Waldenström, B. Olsen); International Center for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh (M. Alam); Uppsala University Department of Medical Biochemistry and Microbiology, Uppsala (L. Sandegren).

Abstract

Multidrug resistance was found in 22.7% of Escherichia coli isolates from bird samples in Bangladesh; 30% produced extended-spectrum β-lactamases, including clones of CTX-M genes among wild and domestic birds. Unrestricted use of antimicrobial drugs in feed for domestic birds and the spread of resistance genes to the large bird reservoir in Bangladesh are growing problems.

Dissemination of Enterobacteriaceae that produce extended-spectrum β-lactamases (ESBLs) is increasing in humans and animals globally (1,2). Clinically relevant sequence and ESBL types have been reported among wild birds (3). Escherichia coli strains from domestic animals and poultry tend to carry the same CTX-M enzyme variants that are locally dominant in human isolates (4). Using birds as sentinels of the spread of antimicrobial drug resistance in the environment could indicate a wider prevalence of drug-resistant disease in humans (3,5).
In Bangladesh, the problem of antimicrobial drug resistance in humans and poultry is augmented by the uncontrolled use of unprescribed antimicrobial drugs (6). A high prevalence of resistant phenotypes has recently been reported in poultry and human E. coli isolates from Bangladesh (6,7). ESBL-producing E. coli and Klebsiella pneumoniae are common in clinical settings (8), but data quantifying the prevalence of different ESBL genotypes are limited. We screened fecal samples from wild birds and from poultry in the Rajshahi district of Bangladesh for antimicrobial-resistant and ESBL-producing E. coli.