Resistance Profiling of Predominant Non–E. coli Enterobacteriaceae Isolated From Humans, Food Animals, and the Environment in the Fako Division of Cameroon

TL;DR

This study examines antibiotic resistance in non-E. coli Enterobacteriaceae from humans, animals, and the environment in Cameroon, finding high resistance rates and the presence of resistance genes.

Contribution

The study provides a one-health approach to resistance profiling in non-E. coli Enterobacteriaceae across multiple sources in Cameroon.

Findings

Quinolones, carbapenems, aminoglycosides, and chloramphenicol were the most effective antibiotics against the isolates.

Multidrug resistance was observed in 25.2% of isolates, with resistance genes detected in isolates from humans, animals, and the environment.

Plasmid-mediated quinolone resistance genes were present in 97.8% of quinolone-resistant isolates.

Abstract

The impact of the current global rising resistance of Enterobacteriaceae to antibiotic agents is of great concern. Detecting and monitoring resistance in these pathogens in humans, animals, and the environment and taking appropriate actions based on results obtained are indispensable to reverse this trend. This study is aimed at contributing to the fight against resistance of predominant non–Escherichia coli Enterobacteriaceae in the Fako Division of Cameroon through a one-health approach. Freshly collected human feces, rectal swabs from pigs, cloacal swabs from chicken, cow intestinal content, and environmental samples were cultured. Isolates were identified using API 20E. Predominant non–E. coli isolates (Enterobacter spp., 65.0%; Salmonella spp., 11%; and Citrobacter spp., 9.9%) were confirmed by polymerase chain reaction (PCR). Antibiotic susceptibility profiles of these isolates were determined by the Kirby-Bauer disc diffusion technique, while the resistant genes were detected by PCR. The quinolones (norfloxacin, 94.7%, and ofloxacin, 91.2%), carbapenem (imipenem, 96%), aminoglycoside (amikacin, 95.5%), and chloramphenicol (91.3%) were the most active drugs. Penicillins (amoxicillin, 24.7%; ampicillin, 21.2%; and amoxicillin–clavulanic acid, 19.9%) were the most inactive drugs. However, isolates showed the highest rate of intermediate susceptibility (48.6%) to cefepime. Out of the 226 isolates, 214 (94.7%) showed resistance to at least one antibiotic agent. Multidrug resistance was found in 54 (25.2%) of the isolates. The predominant antibiotypes were AXR AMR AMCR (25, 11.1%), AXR AMR AMCR AZMR (18, 8.4%), CAZR AXR AMR AMCR (12, 5.3%), and AXR AMCR AZMR (7, 3.1%). Isolates with these antibiotypes were from various sources and predominant genera. Plasmid-mediated quinolone resistance (PMQR) genes (acrA, acrB, qepA, and aac(6⁣′ )-ib-cr) were detected in 97.8% (44/45) of isolates that showed resistance to at least one quinolone antibiotic, while the beta-lactamase genes, blaCMY-2 and blaCTX-M-1, were detected in 7.9% (5/63) and 22.0% (14/63), respectively, in isolates that showed resistance to cephalosporins. These isolates carrying these genes were from humans, food animals, and the environment. Of the 45 isolates, a total of 40 (88.9%) carried two or more PMQR genes, while 2 (0.6%) carried both bla genes (cocarriage). Five (17.9%) isolates out of the 28 screened for PMQR and beta-lactamase genes were positive for both sets of genes. Resistance to antibiotics was high with strains of the different genera carrying PMQR and beta-lactamase resistance genes circulating in humans, food animals, and the environment in the Fako Division of Cameroon.

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