High prevalence of multidrug resistant ESBL- and plasmid mediated AmpC-producing clinical isolates of Escherichia coli at Maputo Central Hospital, Mozambique.

BACKGROUND: Epidemiological data of cephalosporin-resistant Enterobacterales in Sub-Saharan Africa is still restricted, and in particular in Mozambique. The aim of this study was to detect and characterize extended-spectrum ß-lactamase (ESBL) - and plasmid-mediated AmpC (pAmpC)-producing clinical strains of Escherichia coli at Maputo Central Hospital (MCH), a 1000-bed reference hospital in Maputo, Mozambique. METHODS: A total of 230 clinical isolates of E. coli from urine (n = 199) and blood cultures (n = 31) were collected at MCH during August-November 2015. Antimicrobial susceptibility testing was performed by the disc diffusion method and interpreted according to EUCAST guidelines. Isolates with reduced susceptibility to 3rd generation cephalosporins were examined further; phenotypically for an ESBL-/AmpC-phenotype by combined disc methods and genetically for ESBL- and pAmpC-encoding genes by PCR and partial amplicon sequencing as well as genetic relatedness by ERIC-PCR. RESULTS: A total of 75 isolates with reduced susceptibility to cefotaxime and/or ceftazidime (n = 75) from urine (n = 58/199; 29%) and blood (n = 17/31; 55%) were detected. All 75 isolates were phenotypically ESBL-positive and 25/75 (33%) of those also expressed an AmpC-phenotype. ESBL-PCR and amplicon sequencing revealed a majority of blaCTX-M (n = 58/75; 77%) dominated by blaCTX-M-15. All AmpC-phenotype positive isolates (n = 25/75; 33%) scored positive for one or more pAmpC-genes dominated by blaMOX/FOX. Multidrug resistance (resistance ≥ three antibiotic classes) was observed in all the 75 ESBL-positive isolates dominated by resistance to trimethoprim-sulfamethoxazole, ciprofloxacin and gentamicin. ERIC-PCR revealed genetic diversity among strains with minor clusters indicating intra-hospital spread. CONCLUSION: We have observed a high prevalence of MDR pAmpC- and/or ESBL-producing clinical E. coli isolates with FOX/MOX and CTX-Ms as the major ß-lactamase types, respectively. ERIC-PCR analyses revealed genetic diversity and some clusters indicating within-hospital spread. The overall findings strongly support the urgent need for accurate and rapid diagnostic services to guide antibiotic treatment and improved infection control measures.

Longitudinal Surveillance of Antibiotic Resistance in Escherichia coli and Enterococcus spp. from a Wastewater Treatment Plant and Its Associated Waters in KwaZulu-Natal, South Africa.

We assessed the prevalence, distribution, and antibiotic resistance patterns of Escherichia coli and Enterococcus spp. isolated from raw and treated wastewater of a major wastewater treatment plant (WWTP) in KwaZulu-Natal, South Africa and the receiving river water upstream and downstream from the WWTP discharge point. Escherichia coli and enterococci were isolated and counted using the Colilert®-18 Quanti-Tray® 2000 and Enterolert®-18 Quanti-Tray 2000 systems, respectively. A total of 580 quantitative PCR-confirmed E. coli and 579 enterococci were randomly chosen from positive samples and tested for in vitro antibiotic susceptibility using the disk diffusion assay against 20 and 16 antibiotics, respectively. The removal success of the bacterial species through the treatment procedure at the WWTP was expressed as log removal values (LRVs). Most E. coli were susceptible to meropenem (94.8%) and piperacillin-tazobactam (92.9%), with most Enterococcus susceptible to ampicillin (97.8%) and vancomycin (96.7%). In total, 376 (64.8%) E. coli and 468 (80.8%) Enterococcus isolates showed multidrug resistance (MDR). A total of 42.4% (246/580) E. coli and 65.1% (377/579) enterococci isolates had multiple antibiotic resistance indices >0.2. The LRV for E. coli ranged from 2.97 to 3.99, and for enterococci the range was observed from 1.83 to 3.98. A high proportion of MDR E. coli and enterococci were present at all sampled sites, indicating insufficient removal during wastewater treatment. There is a need to appraise the public health risks associated with bacterial contamination of environmental waters arising from such WWTPs to protect the health of users of the receiving water bodies.

Antibiotic resistant Klebsiella spp. from a hospital, hospital effluents and wastewater treatment plants in the uMgungundlovu District, KwaZulu-Natal, South Africa.

Hospital effluents are crucial hotspots for the dissemination of antibiotic resistant microorganisms. This study analysed hospital effluent and proximate wastewater treatment plants for the presence of antibiotic resistant Klebsiella spp. Water samples were obtained twice over a three-month period from an urban and rural hospital at three effluent points each, and from two proximate wastewater treatment plants (WWTPs) comprising influent and effluent and river water samples up/downstream the WWTPs. Presumptive Klebsiella spp. were enumerated, isolated, and phenotypically confirmed using a well-established commercial test system for Enterobacteriaceae (API20E). Clinical Klebsiella pneumoniae isolates were provided by a hospital for comparison. The antibiotic resistance profiles of Klebsiella spp. isolates to 16 selected antibiotics were established according to EUCAST (European Committee on Antimicrobial Susceptibility Testing). In addition, extended spectrum ß-lactamase (ESBL) and carbapenemase production was analysed. A total of 93 confirmed Klebsiella spp. isolates from hospital effluents and 37 from WWTPs were obtained, comprising K. pneumoniae and K. oxytoca. The viable counts for confirmed Klebsiella spp. for hospital effluents ranged from 1.38 × 102 to 1.03 × 104, while those for WWTP influent were in a range of 1.76 × 103 to 5.10 × 103 CFU/ml. A higher proportion of Klebsiella spp. from urban hospital effluent was categorized as multidrug-resistant (MDR) (23%) compared to rural hospital effluent (9%). Resistance was observed to all antibiotic classes tested. Several clinical isolates presented resistance to four carbapenem antibiotics, while certain isolates from hospital effluent and WWTPs exhibited ertapenem and doripenem resistance. Fifteen Klebsiella spp. isolates (clinical and from urban hospital effluent) produced carbapenemases. Hospital effluents in South Africa contain antibiotic resistant Klebsiella spp. and may pose a risk to proximate informal communities if inadequately treated. Moreover, common phenotypic resistance profiles among isolates from the clinical-hospital effluent-wastewater works continuum suggest a need for further treatment of such effluent.