Background: Staphylococcus aureus  is an important human pathogen causing a wide variety of diseases ranging from mild skin infections to life-threatening bacteremia. This study aimed to provide insight into the phenotype–genotype characteristics of S. aureus  isolated from neonates.
Methods: A hospital-based retrospective study was conducted to recruit neonatal patients with community-associated S. aureus  infection. All 92 S. aureus  clinical isolates were tested for antimicrobial susceptibility, resistance genes, virulence genes, and multilocus sequence typing.
Results: A total of 92 S. aureus  isolates were included in this study, including 29 (31.5%) MRSA isolates. Most S. aureus  isolates were susceptible to gentamicin, and most methicillin-resistant S. aureus  (MRSA) isolates were susceptible to vancomycin and linezolid. The predominant S. aureus  genotypes were CC188 (ST188), CC59 (ST338), CC5 (ST5), CC88 (ST8), and CC6 (ST6), with CC59 (ST338) as the most prevalent MRSA. We observed a significantly corresponding relationship between clonal complexes and resistance patterns (such as CC45/CC59/CC121/CC630 associated with multidrug resistance) or the number of virulence genes (such as CC1/CC5/CC45/CC59/CC88 associated with harboring 5– 7 virulence genes, and CC22/CC25/CC121 associated with carrying 8– 13 genes). Moreover, both univariate and multivariate analyses indicated that invasive S. aureus  isolates were significantly associated with resistance to several classes of antibiotics and carrying specific virulence factors.
Conclusion: Our findings provide insight into phenotype–genotype characteristics for S. aureus  isolates so as to provide new ideas for differentiating potential genetic backgrounds and monitoring new epidemiologic trends.
Keywords: Staphylococcus aureus , antimicrobial susceptibility, molecular characterization, virulence genes