Clinical and molecular characteristics of invasive community-acquired methicillin-resistant Staphylococcus aureus infection in Chinese neonates
Objective 
To analyze the clinical and molecular features of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection in neonates and to investigate their antibiotic resistance profiles. 
 
 
Methods 
A total of 35 invasive CA-MRSA strains were collected from six hospitals in 2014. Multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec) typing and spa typing were used to analyze these isolated CA-MRSA strains. In vitro antibiotic susceptibilities of those strains to 15 antibiotics were analyzed by using agar dilution method. 
 
 
Results 
Up to 88.6% patients were late-onset infection and septicemia (24, 68.5%) was the most common infection among the 35 cases. A total of 16 patients (45.7%) suffered from complications. Caesarean section and premature birth were risk factors for invasive CA-MRSA infection. ST59-MRSA-SCCmecⅣa-t437 (14, 40%) was the most predominant CA-MRSA clone, followed by ST59-MRSA-SCCmecⅤ-t437 (13, 37.1%). The incidence of severe complications caused by ST59-MRSA-SCCmecⅤ-t437 was higher than that caused by ST59-MRSA-SCCmecⅣa-t437 (P<0.05). Up to 85.7% of the isolated CA-MRSA strains were multidrug-resistant strains. 
 
 
Conclusion 
This study shows that neonatal invasive CA-MRSA infections mainly result in septicemia and are often accompanied by complications and involve multiple organs. Multidrug-resistant CA-MRSA strains are prevalent in neonates. ST59-MRSA-SCCmecⅣa-t437 is the predominant clone causing neonatal invasive CA-MRSA infection. 
 
 
Key words: 
CA-MRSA; Neonate; Invasive infection