Comparison of nosocomial infection rates in a neonatal intensive care unit before and after moving into a new location

women. This study aimed to screen the antimicrobial susceptibility and the virulent factors of SA strains isolated from patients with puerperal mastitis. Methods: All SA isolated from the clinical specimens obtained from patients with puerperal mastitis were tested. Susceptibility to common antimicrobial agents was determined using the disk diffusion method. The genes encoding antimicrobial resistance(mecA) and virulent factors encoding the exotoxins(pvl, eta, etb, and tsst) and classic staphylococcal enterotoxins (SEs)(sea, seb, sec, sed, and see) were tested by specific PCR. Some strains were selected for multilocus sequence typing(MLST). Results: A total of 76 SA isolates were obtained from 48 women, 51(67.1%) isolates were oxacillin resistant(ORSA). Most ORSAs were susceptible to the antimicrobial agents [Susceptible rates: gentamicin(67.3%), TMP/ SMX(98.0%), 100% to teicoplanin, rifampin, fusidic acid, linezolid, levofloxacin, doxycycline], but resistant to clindamycin(6.1%) and erythromycin(6.1%); while most of the OSSA isolates were susceptible to clindamycin(74.1%) and erythromycin(74.1%). All but one ORSA carried mecA gene. Of the 76 SA strains, 42.1%(32/76) were positive for pvl, 68.4%(52/76) were positive for at least one enterotoxin genes. Few isolates carried eta 8/76(10.5%), etb 0/76, and tsst 3/76(3.9%). Sequence type 59(ST 59) was the most common(26 strains) type among the 29 SA with MLST performed. Conclusions: Oxacillin resistance was common among SA isolated from puerperal mastitis, but some other common antimicrobial agents remained susceptible, e.g., fusidic acid and TMP/SMX. The association with abscess formation and pvl positive SA infection is not significant.