Environmental reservoirs of high-risk ESBL- and carbapenemase-producing E. coli and Klebsiella in maternity wards in Yaounde (Cameroon): Whole-genome sequencing and antimicrobial susceptibility studies

BackgroundThe hospital environment is increasingly recognized as a critical reservoir for antimicrobial-resistant (AMR) bacteria. In sub-Saharan Africa, maternity wards represent high-risk settings where environmental contamination poses a direct threat to vulnerable mothers and neonates. Despite this, there is a significant lack of data integrating phenotypic resistance with whole-genome sequencing (WGS) to understand antimicrobial resistance (AMR) in these settings. This study characterized the AMR patterns and genomic features of ESBL-producing Escherichia coli and Klebsiella spp. isolated from maternity ward surfaces in Yaounde, Cameroon. MethodsA cross-sectional environmental study was conducted across four maternity wards. Isolates were identified via standard microbiological methods, and antimicrobial susceptibility testing against 13 antibiotics was performed following EUCAST 2024 guidelines. Short-read WGS was utilized to identify sequence types (STs), plasmid incompatibility groups, antibiotic resistance genes (ARGs), and virulence factors. Plasmid-ARG association networks were constructed to visualize resistance dynamics. ResultsNineteen ESBL-producing Enterobacterales were identified, comprising 15 E. coli and four Klebsiella isolates. High levels of multidrug resistance were observed against ciprofloxacin, penicillins, and third-generation cephalosporins. While the isolates remained sensitive to colistin and imipenem, alarming resistance to meropenem was detected. Genomic analysis revealed the presence of globally disseminated high-risk lineages, including E. coli ST131, ST1193, and ST410, alongside Klebsiella ST1324 and ST489. Critical resistance determinants, including ESBLs, AmpC enzymes, and carbapenemases (NDM and OXA-48-like), are frequently associated with epidemic plasmids such as IncF, IncA/C2, and IncL/M. Additionally, the isolates harboured virulence factors characteristic of extraintestinal pathogenic Enterobacterales. ConclusionsThe widespread presence of high-risk carbapenemase-producing clones on maternity ward surfaces identifies the hospital environment as a significant AMR reservoir in Yaounde. These findings highlight the urgent need for reinforced infection prevention and control (IPC) measures, robust antimicrobial stewardship, and the integration of genomic surveillance to safeguard highly susceptible maternal and neonatal populations from life-threatening infections.