Prevalence and Characterization of Staphylococcus aureus Isolated From Women and Children in Guangzhou, China

Abstract

The prevalent <i>Staphylococcus aureus</i> clones and antibiotic susceptibility profiles are known to change dynamically and geographically; however, recent <i>S. aureus</i> strains causing infections in women and children in China have not been characterized. In this study, we analyzed the molecular epidemiology and antimicrobial resistance of <i>S. aureus</i> isolated from patients in four centers for women and children in Guangzhou, China. In total, 131 <i>S. aureus</i> isolates (100 from children and 31 from women) were analyzed by spa typing, multi-locus sequence typing, virulence gene and antimicrobial resistance profiling, staphylococcal chromosomal cassette <i>mec</i> typing, and mutation analyses of <i>rpoB</i>. A total of 58 spa types, 27 sequence types (STs), and 10 clonal complexes (CCs) were identified. While CC59 (ST59-IV, 48.8%; ST338-III, 35.7%) and CC45 (ST45-IV, 100%) were the major clones (84.4%) among MRSA isolates, CC5 (ST188, 24.3%; ST1, 21.6%) and CC398 (ST398, 70%) were the major ones (70.1%) among MSSA isolates. ST338-MRSA-III mostly found in pus but hardly in respiratory tract samples while ST45-MRSA-IV was on the opposite, even though they both found in blood and cerebrospinal fluid sample frequently. Staphylococcal enterotoxin genes <i>seb</i>-<i>seq</i>-<i>sek</i> were strongly associated with ST59 and ST338, while <i>sec</i> was associated with ST45, ST121, ST22, and ST30. All ST338, ST1232, and SCC<i>mec</i> III isolates carried <i>lukF/S-PV</i> genes. A total of 80% of ST338 isolates were resistant to erythromycin, clindamycin, and tetracycline. All ST45 isolates exhibited intermediate or complete resistance to rifampicin. In total, 481 HIS/ASN mutations in <i>rpoB</i> were found in rifampicin-resistant or intermediate-resistant isolates. ST338-III and ST45-IV emerged as two of three major clones in MRSA isolates from women and children in Guangzhou, China, though ST59-MRSA-IV remained the most prevalent MRSA clone. Clonal distribution of <i>S. aureus</i> varied, depending on the specimen source. Virulence genes and antibiograms were closely associated with the clonal lineage. These results clarified the molecular epidemiology of <i>S. aureus</i> from women and children in Guangzhou, China, and provide critical information for the control and treatment of <i>S. aureus</i> infections.