Carbapenemase genes in hospital wastewater in Africa: A systematic review and meta-analysis

Hospitals may be a significant reservoir of antibiotic-resistant genes, including carbapenemase genes. This study aimed to evaluate the prevalence and distribution of carbapenemase genes in hospital wastewater in Africa. We conducted a comprehensive search on carbapenemase genes in hospital wastewater in Africa up to November 31, 2024, using PubMed, Google Scholar, and African Journal Online (AJOL) databases. We included original studies without time or language restrictions. The meta-analysis used the R package metafor with a random effects model due to expected heterogeneity among studies. Heterogeneity was assessed using the I2 statistic. We included 13 studies conducted in seven African countries. Compared with those in treated wastewater, carbapenem genes were more enriched in raw wastewater. Among the 13 different carbapenemase genes reported, 9 (69.2%) genes were specific to the raw wastewater group, including blaIMP, blaVIM, blaOXA-181, blaOXA-69, blaOXA-1-like, blaOXA-48-like, blaGES, blaOXA-416, and blaOXA-51. They are more commonly isolated from enterobacteria (7; 58.3%). The estimated overall prevalence was 23.8% (95% CI: 15.4% 1-33.4%), and the heterogeneity between studies was substantial (I2 = 96.1%; p<0.01). This review emphasizes the presence of carbapenemase genes in hospital wastewater in Africa, showing a high prevalence. African hospitals should focus on controlling the spread of these genes in wastewater and prioritize the safety of health professionals and patients. IMPORTANCEAntibiotic resistance poses a significant threat to global public health. It is a complex process influenced by host, environmental, and pathogen factors. Effluents, especially from hospitals, are substantial sources of antibiotic-resistant bacteria due to high bacterial loads, nutrients, and low levels of antibiotics. Improper handling and disposal of hospital effluents can pose a risk to public health by promoting the spread of resistance genes. Sanitation and hospital waste management standards in Africa vary significantly. Hospital wastewater can be a significant source of antibiotic-resistance genes, including carbapenemase genes. Carbapenemases can hydrolyze penicillins, cephalosporins, and carbapenems, making them a serious public health concern as carbapenems are often the last resort antibiotics for treating multiresistant bacteria. This review aims to assess the prevalence and distribution of carbapenemase genes in hospital wastewater across Africa.