Background
Extended-spectrum β-lactamase (ESBL), plasmid-mediated AmpC-β-lactamase and carbapenemase producing Escherichia coli and Klebsiella pneumoniae have spread into environment worldwide posing a possible public health threat. However, the prevalence data in low- and middle-income countries are still scarce. The aim of this study was to assess the occurrence of ESBL, AmpC-β-lactamase and carbapenemase producing and multidrug-resistant E. coli and K. pneumoniae in wastewater collected from healthcare centers in Burkina Faso.
Methodology
Eighty-four (84) wastewater samples were collected from 5 healthcare centers and bacterial counts on ESBL ChromAgar were performed. E. coli and K. pneumoniae isolates were identified using API20E. ESBL production was confirmed using the double disc synergy test (DDST). AmpC-β-lactamase detection was performed on Muller Hinton (MH) agar supplemented with cloxacillin (4µg/l). Carbapenemase testing was carried out using O.K.N.V.I. RESIST-5 immunochromatography test.
Result
E. coli and/ or K. pneumoniae strains were isolated from 82 wastewater samples (97.6%). In total, 170 strains were isolated, E. coli more commonly (64%). Average concentrations of ESBL producing bacteria per hospital varied from 1.10x105 to 5.23x106 CFU/ml. Out of 170 presumptive ESBL producing isolates and 51 presumptive AmpC-β-lactamase producing isolates, 95% and 45% were confirmed, respectively. Carbapenemase production was detected in 10 isolates, 6 were NDM producers, 3 were OXA-48 producers and 1 was NDM and OXA-48 producer. All isolates were multidrug resistant and, furthermore, all of them were resistant to all β-lactams tested. Also, resistance to ESBL inhibitors was common, up to 66% E. coli and 62% in K. pneumoniae. Amikacin, fosfomycin and nitrofurantoin were the antibiotics for which least resistance was detected.
Conclusion
This study showed that wastewater from healthcare centers constitutes a reservoir of multidrug-resistant bacteria in Burkina Faso, including those capable of producing carbapenemases, which may disseminate into environment and further back to humans. Therefore, following the microbiological quality of the wastewaters released from healthcare centers is important to include in the future national AMR surveillance program.