IMPORTANCE: With increasing levels of CA-MRSA reported from most parts of the Western world, there is a great interest in understanding the origin and factors associated with the emergence of these epidemic lineages. To trace the origin, evolution, and dissemination pattern of the European CA-MRSA clone (CC80), we sequenced a global collection of strains of the S. aureus CC80 lineage. Our study determined that a single descendant of a PVL-positive methicillin-sensitive ancestor circulating in sub-Saharan Africa rose to become the dominant CA-MRSA clone in Europe, the Middle East, and North Africa. In the transition from a methicillin-susceptible lineage to a successful CA-MRSA clone, it simultaneously became resistant to fusidic acid, a widely used antibiotic for skin and soft tissue infections, thus demonstrating the importance of antibiotic selection in the success of this clone. This finding furthermore highlights the significance of horizontal gene acquisitions and underscores the combined importance of these factors for the success of CA-MRSA.
MATERIALS AND METHODS: A total of 7204 clinical specimens from HIV patients from 2012 to 2017 were processed for the isolation of S. aureus strains using conventional culture techniques and cultures were identified using standard biochemical test. Antibiotic susceptibility of S. aureus strains was tested by Kirby-Bauer disk diffusion method.
RESULTS: A total of 380 (5.3%) S. aureus strains were isolated from HIV patients in the study period. High percentage of S. aureus strains were isolates from urine (69.5%) specimen and 58.4% of S. aureus infections were noted among hospitalized patients. Antibiotic susceptibility profile reveals S. aureus was highly resistant to penicillin (95.2%) followed by cephalexin (84.6%). Methicillin resistance was highly observed in the year 2017 (86%) and the rate of MRSA steadily increasing from 51.8% in 2012 to 86% in 2017. Significant increase of S. aureus infections (35%; p<0.001) and MRSA (76%; p=0.0007) were observed in the year 2016.
CONCLUSIONS: This study reports the increasing trends of S. aureus infections and MRSA among HIV patients from Southern India. Multidrug-resistance profile of S. aureus could complicate the selection of proper antibiotic regimens and time cure of HIV patients.