Abstract:
Abstract
Difficult-to-treat infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are of concern in people living with
HIV infection as they are more vulnerable to infection. We aimed to identify molecular characteristics of MRSA colonizing
newly diagnosed HIV-infected adults in Tanzania. Individuals newly diagnosed with HIV infection were recruited in
Dar es Salaam, Tanzania, from April 2017 to May 2018, as part of the randomized clinical trial CoTrimResist (ClinicalTrials.
gov identifier: NCT03087890). Nasal/nasopharyngeal isolates of Staphylococcus aureus were susceptibility tested by disk
diffusion method, and cefoxitin-resistant isolates were characterized by short-reads whole genome sequencing. Four percent
(22/537) of patients carried MRSA in the nose/nasopharynx. MRSA isolates were frequently resistant towards gentamicin (95%),
ciprofloxacin (91%), and erythromycin (82%) but less often towards trimethoprim-sulfamethoxazole (9%). Seventy-three per cent had inducible clindamycin resistance. Erythromycin-resistant isolates harbored ermC (15/18) and LmrS (3/18) resistance
genes. Ciprofloxacin resistance was mediated by mutations of the quinolone resistance-determining region (QRDR) sequence in
the gyrA (S84L) and parC (S80Y) genes. All isolates belonged to the CC8 and ST8-SCCmecIV MRSA clone. Ninety-five
percent of the MRSA isolates were spa-type t1476, and one exhibited spa-type t064. All isolates were negative for Panton Valentine leucocidin (PVL) and arginine catabolic mobile element (ACME) type 1. All ST8-SCCmecIV-spa-t1476 MRSA
clones from Tanzania were unrelated to the globally successful USA300 clone. Carriage of ST8 MRSA (non-USA300) was
common among newly diagnosed HIV-infected adults in Tanzania. Frequent co-resistance to non-beta lactam antibiotics limits
therapeutic options when infection occurs.
