Whole Genome Sequencing of Multidrug-Resistant Staphylococcus haemolyticus circulating in pregnant individuals in Brazil

Staphylococcus haemolyticus is a leading cause of nosocomial and bloodstream infections with high prevalence in neonatal settings, being the anovaginal colonization of pregnant women the main source of vertical transmission. We obtained the whole genome sequence of 19 multidrug resistant-S. haemolyticus strains from anovaginal colonization among pregnant women attending a single maternity in Rio de Janeiro, Brazil, between March 2019 and August 2022. Anovaginal samples were streaked onto chromogenic media and colonies were identified by MALDI-TOF MS. Antimicrobial susceptibility was evaluated according to CLSI. Whole genome sequencing was performed using the Illumina platform, and genomic data analysis was developed using CARD, ResFinder, PubMLST and BLAST databases. All (19) strains showed resistance to β – lactams and macrolides. Also, 57.9% (11) were non-susceptible to tetracycline, 52.6% (10) were non-susceptible to sulfamethoxazole/trimethoprim, 42.1% (8) were non-susceptible to quinolones and 21.1% (4) were non-susceptible to lincosamides. All strains carried the mecA and blaZ. Macrolide-associated resistance genes ermC, mphC and msrA were identified among 36.8% (7), 47.4% (9) and 57.9% (11) of strains, respectively. Moreover, 52.6% (10) of strains carried either the tetK or tetL genes. Three SCCmec types were identified: Vc (17; 89.5%), I and IX (1; 5.3% each). ST8 (5; 26.3%) and ST30 (4; 21.1%) were the most prevalent, followed by ST1 and ST54 (2; 10.6% each); ST58 and ST132 (1; 5.3% each). Three novel STs, 156, 157, 158 (1; 5.3% each) were included in PubMLST database, and one strain could not be typed. Overall, 73.7% (14) of strains belonged to CC3, carrying the SCCmec type Vc, which has been reported has a major clonal complex worldwide, associated with human infections and a wide range of antimicrobial resistance phenotypes. Thus, this data highlights the need for continuous epidemiological surveillance of this important multidrug-resistant pathogen within our setting.