Extended-spectrum beta-lactamase and carbapenemase producing Klebsiella spp. from hospital effluents in South Africa. ESBL & carbapenemase producing Klebsiella spp. from hospital effluents

Hospital effluents represent critical hotspots for the dissemination of antibiotic resistant microorganisms and may consequently threaten public health if inadequately disposed of. This study analysed hospital effluents and WWTPs for the presence of ABR Klebsiella spp. Water samples were obtained twice over a three-month period from two hospitals (urban and rural) and two WWTPs. Samples were taken at three points at each hospital, as well as from WWTP influent, effluent and up/downstream the proximate rivers. Membrane filtration and chromogenic agar was used to enumerate and isolate presumptive Klebsiella spp., and confirmation was achieved via API20E. Clinical Klebsiella isolates were provided by the urban hospital. Antibiotic resistance profiles to 16 antibiotics were established according to EUCAST, and ESBL and carbapenemase production was elucidated. Representative isolates were chosen for whole genome sequencing. A total of 93 Klebsiella isolates from hospitals and 37 from WWTPs were obtained, comprising K. pneumoniae and K. oxytoca (API20E). A higher proportion of Klebsiella spp. from urban hospital effluent was MDR (23%) compared to rural hospital effluent (9%), and resistance was observed to antibiotics across all tested classes. Clinical and effluent isolates presented resistance to multiple carbapenem antibiotics: fifteen isolates were carbapenemase producers, comprising clinical (n=14) and urban hospital effluent (n=1). WGS analysis including average nucleotide identity revealed a Klebsiella michiganensis isolate from urban hospital effluent exhibiting carbapenemase blaOXA-181, while clinical isolates from the same hospital harboured the blaNDM-1 carbapenemase. Additional beta-lactamase (blaCTX-M, TEM), aminoglycoside (aac(3), aph(3)) and quinolone (oqxAB, qnrB) resistance genes were detected in Klebsiella isolates. Sequence type 872 and ST-307 were common among both hospital effluent and clinical isolates. Hospital effluents in South Africa contain ABR Klebsiella spp. and may pose a risk to proximate informal communities if inadequately treated. Moreover, common pheno/genotypic resistance profiles among isolates from the clinical-hospital effluent-wastewater works continuum infer a need for further treatment of such effluent