Transmission Dynamics of Antimicrobial Resistance at a National Referral Hospital in Uganda

Reliable data on antimicrobial resistance (AMR) transmission dynamics in Uganda remains scarce; hence, we studied this area. Eighty-six index patients and "others" were recruited. Index patients were those who had been admitted to the orthopedic ward of Mulago National Referral Hospital during the study period; "others" included medical and non-medical caretakers of the index patients, and index patients' immediate admitted hospital neighbors. Others were recruited only when index patients became positive for carrying antimicrobial-resistant bacteria (ARB) during their hospital stay. A total of 149 samples, including those from the inanimate environment, were analyzed microbiologically for ARB, and ARB were analyzed for their antimicrobial susceptibility profiles and mechanisms underlying observed resistances. We describe the diagnostic accuracy of the extended-spectrum β-lactamase (ESBL) production screening method, and AMR acquisition and transmission dynamics. Index patients were mostly carriers of ESBL-producing Enterobacteriaceae (PE) on admission, whereas non-ESBL-PE carriers on admission (61%) became carriers after 48 hours of admission (9%). The majority of ESBL-PE carriers on admission (56%) were referrals or transfers from other health-care facilities. Only 1 of 46 samples from the environment isolated an ESBL-PE. Marked resistance (> 90%) to β-lactams and folate-pathway inhibitors were observed. The ESBL screening method's sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 50%, 90%, and 100%, respectively. AMR acquisition and transmission occurs via human-human interfaces within and outside of health-care facilities compared with human-inanimate environment interfaces. However, this remains subject to further research.