Sub-Saharan Africa faces a growing antimicrobial resistance (AMR) threat. Antimicrobial resistant bacterial organisms pose a serious problem to human infection treatment, particularly urinary tract infections and bloodstream infections. Due to inadequate surveillance systems, information gaps on AMR prevalence in Africa (including Namibia) exist.

A systematic review of the WHO African region (2008-2019) analysed 27 bacteremic E. coli and S. aureus AMR studies. Additionally, a nationwide retrospective AMR analysis of Namibian female urine (2016-2017, Study II) and all patients blood (2011-2019, Study III) isolates was conducted. Antibiotic susceptibility testing (AST) was performed using disk diffusion and Vitek 2 according to CLSI guidelines.

Study I revealed that E. coli median resistance was: cefotaxime (42%), ciprofloxacin (44%) and carbapenems (<1%). The S. aureus resistance rates for cloxacillin was 34%. Study II estimated ESBL bacterial isolates prevalence at 22% based on cefotaxime resistance. Nitrofurantoin resistance was low in non-ESBL isolates but increased in ESBL isolates (12.9% to 19%), with one region reaching 59% resistance. Study III found that the E. coli resistance was: piperacillin-tazobactam (8%), cefotaxime (32%), ciprofloxacin (29%), gentamicin (18%) and co-trimoxazole (79%). S. aureus showed 18.8% oxacillin resistance with low resistance (<10%) to clindamycin, gentamicin and rifampin and none to teicoplanin.

This study highlights the limited bacteremic AMR data from only a quarter of WHO African region countries, thereby emphasising the need for strengthened surveillance. In Namibia, nitrofurantoin remains a useful empirical antimicrobial for female urinary tract infections, although regional variations necessitate enhanced surveillance. The high resistance rates in bacteremic E. coli (>20%) for most antimicrobials in Namibia underscore the importance of AST-guided therapy.