Cluster analysis and geospatial mapping of antibiotic resistant Escherichia coli O157 in southwest Nigerian communities

Geospatial spread and antibiotic-resistant relatedness of Escherichia coli O157, which are important virulent serotypes causing severe complications leading to high intestinal morbidity and occasional mortality in several communities in southwest Nigeria, were evaluated.Biotyped Escherichia coli strains (n = 508) from subjects with diarrhea and related intestinal infections, various domestic water sources and food animal products were evaluated for antibiotic resistance relatedness, con-jugative activity, virulence factor and biofilm production. Antibiotic resistance of Escherichia coli O157 encoded with stx was mapped for geospatial spread.Detected stx-encoded Escherichia coli O157 (7.56%) of human strains were significantly higher compared to water and food animal strains (p = 0.001) with high conjugative and transformative activity (OR(95%CI) = 34.65(94.5); p = 0.023). Water-Escherichia coli O157 reveal significant median resistance to ciprofloxacin, gentamycin (p < 0.05) and human diarrheagenic strains showed >60% resistance to doxycycline (MIC50 8 mu g/mL and MIC90 128 mu g/mL; p = 0.018), tetracycline (MIC50 4 mu g/mL and MIC90 64 mu g/mL), ciprofloxacin (MIC50 2 mu g/ mL and MIC90 128 mu g/mL) and gentamycin (MIC50 4 mu g/mL and MIC90 256 mu g/mL). Strains from human diar-rhea, UTI, colitis, cattle, fish, sheep, ground waters, streams, and rivers characterized with biofilm, hemolysin, protease productions, R-plasmid (approximate to 14.30kbp) and MARI (0.84) were highly related. Principal component analysis (score plot) revealed a significant association between resistant human diarrheic strains with cattle and poultry strains. A high population of heterogeneous stx-encoded diarrheagenic and colitis strains was predom-inant in urban settings spreading with food animal and water Escherichia coli O157 strains. Human diarrheagenic Escherichia coli O157 were highly related to antibiotic resistance and virulence pattern with water and animal products strains. Strategic interventions through the implementation of One Health approach and population-target antimicrobial stewardship are needed to mitigate the increasing intestinal morbidity and reduction of mortality impact. Regular application of spatial data on clonal dissemination is important for monitoring, surveillance of antimicrobial resistance and transmission of zoonotic food-borne Escherichia coli O157 pathogens.

Automated summary

The study evaluated the geospatial spread and antibiotic-resistant relatedness of Escherichia coli O157 in southwest Nigeria, which is an important virulent serotype causing severe complications. The results showed that human strains of stx-encoded Escherichia coli O157 were more prevalent compared to water and food animal strains, and exhibited high conjugative and transformative activity. The strains also displayed resistance to several common antibiotics. Analysis of the strains from different sources revealed similar biological characteristics and resistance patterns. The study highlights the importance of implementing One Health approach and population-target antimicrobial stewardship to mitigate the spread of antibiotic-resistant Escherichia coli O157 and reduce its impact on intestinal morbidity and mortality.