A retrospective assessment of antimicrobial resistance patterns in WHO-access, watch, and reserve-classified antibiotics across two large hospitals in a resource-limited setting

Antimicrobial resistance (AMR) remains a significant threat. To ensure efficient use of antibiotics, the WHO AWaRe Antibiotics classification framework classifies antibiotics into three groups: Access, Watch, and Reserve. Tracking antibiotic resistance across these groups remains a critical task. This retrospective study examined the prevalence of resistance within the AWaRe Antibiotics classification framework in two large hospitals in Abuja Nigeria. A total of 14,423 microbial culture test results were sourced and retrieved from the hospitals between January and December 2023, of which 3,987 (27.64%) showed microbial growth and with antimicrobial susceptibility results. Six different sample types were analyzed, with urine samples (36.22%) yielding the highest number of isolates. Escherichia coli (23.78%) was the most identified microbe. The overall AMR rate across the AWaRe classification was 41.96%. For the Access category, highest resistance was reported for Doxycycline at 100% resistance while the lowest resistance was reported for Amikacin at 24.63%. For the Watch category, the highest resistance was reported for Cefuroxime at 85.71% while the lowest resistance was reported for ticarcillin/clavulanic acid and Netilmicin, both with 0% resistance. For the Reserve category, the highest resistance was reported for Aztreonam at 67.96% while the lowest resistance was reported for Polymixin B at 9.71%. Cumulatively, antimicrobials in the Access category had a resistance prevalence rate of 44.29%; those in the Watch category had a resistance prevalence rate of 46.65%; while those in the Reserve category had a resistance prevalence rate of 34.95%. More than 70% of multi-drug resistance was observed in frequently used antibiotics such as Cefuroxime, Ceftazidime, and Meropenem. Additionally, over 60% resistance was found in antibiotics like Ertapenem, Aztreonam, and Teicoplanin even though they are not readily available in Nigeria. Every microbe reported in this study was resistant to more than one antimicrobial agent. The most resistant microbes were Staphylococcus aureus, Klebsiella spp., Streptococcus spp., and Escherichia coli. Across gender, positive isolates were found more in women than men across almost all the microbes identified. These results, based on real patient data, highlight the urgent need for an institutionalized AWaRe Antibiotics framework across healthcare facilities in addition to broader strategies of antimicrobial stewardship, pharmaceutical supply chain enhancement, and national AMR surveillance.