Fecal Carriage of Extended-Spectrum -Lactamases in Healthy Humans, Poultry, and Wild Birds in Leon, NicaraguaA Shared Pool of blaCTX-M Genes and Possible Interspecies Clonal Spread of Extended-Spectrum -Lactamases-Producing Escherichia coli

Antibiotic-resistant bacteria are a major concern in the healthcare of today, especially the increasing number of gram-negative bacteria producing -lactamases such as extended-spectrum -lactamases (ESBLs). However, little is known about the relationship of ESBL producers in humans and domestic and wild birds, especially in a low-income setting. Therefore, we studied the fecal carriage of ESBL-producing Escherichia coli and Klebsiella pneumoniae in healthy humans, poultry, and wild birds in the vicinity of Leon, Nicaragua. Three hundred fecal samples were collected during December 2012 from humans (n=100), poultry (n=100) and wild birds (n=100). The samples were examined for ESBL-producing E. coli and K. pneumoniae, revealing the prevalence of 27% in humans, 13% in poultry, and 8% in wild birds. Further characterization of the ESBL-producing isolates was performed through polymerase chain reaction (PCR) (NDM, CTX-M), epidemiological typing (ERIC2-PCR), multilocus sequence typing, and sequencing. ESBL producers harbored bla(CTX-M-2), bla(CTX-M-15), bla(CTX-M-22), and bla(CTX-M-3) genotypes. The bla(CTX-M-15) constituted the absolute majority of ESBL genes among all samples. ERIC-PCR demonstrated highly related E. coli clones among humans, poultry, and wild birds. Clinically relevant E. coli clone ST648 was found in humans and poultry. There is a shared pool of bla(CTX-M) genes between humans and domesticated and wild birds in Nicaragua, and the results suggest shared clones of ESBL-producing E. coli. The study adds to the notion that wild birds and poultry can pick up antibiotic-resistant bacteria of human origin and function as a melting pot of resistance. Structured surveillance programs of antimicrobial resistance and a more regulated prescription of antibiotics are warranted in Nicaragua.