Fecal carriage and phylodiversity of community-acquired blaTEM enteric bacilli in southwest Nigeria

Abstract

Purpose: Increasing rates of clonal spread of fecal blaTEM bacilli remains a huge concern to the community health with resultant high morbidity. The fecal carriage and clonal diversity of blaTEM within the communities in Southwest Nigeria were surveyed. Materials and methods: Enteric bacilli obtained from fresh fecal samples randomly collected from community residents were biotyped and profiled for antibiotic susceptibility. Resistant strains were typed for beta-lactamase, extended-spectrum beta-lactamases (ESBL), AmpC and carbapenemase production while the R-plasmid carriage was detected and mating activities were examined. The presence of blaTEM gene was assayed by PCR and its phylodiversity determined with 16sRNA genomic profiling. Results: Escherichia coli have the highest (28.6%) occurrence rate and Pseudomonas aeruginosa (20.5%) showing significant resistance to beta-lactamase inhibitors (ampicillin, cefuroxime and cefotaxime), and high-level multidrug resistance of more than 15.2% rate to ampicillin, cefuroxime, ceftazidime, tetracycline and imipenem. E. coli and Klebsiella oxytoca, are the highest beta-lactamase, ESBL and AmpC producers encoded with high molecular weight R-plasmid (>11.0 kbp) and significant rate of conjugation and transformational activities. Only 2/14, 1/13 and 1/6 ESBL-type of E. coli, K. oxytoca and Enterobacter cloaca, expressed blaTEM gene, clustering into five different phylodiverse groups with close genomic relatedness with other bacilli. Conclusion: This is an indication of clonal dissemination of ESBL blaTEM encoded enteric bacilli having high phylodiverse characteristics through fecal carriage in the Nigerian community which requires public health education, food and environmental hygiene for its prevention.