Prevalence of Panton-Valentine leukocidin genes and antimicrobic resistance in Staphylococcus aureus isolates from outpatients with skin and soft-tissue infections in Wuhan city

Abstract

Objective To estimate the prevalence of Panton-Valentine leukocidin (PVL) genes and antimicrobial resistance in methicillin-sensitive Staphylococcus aureus (MSSA) isolateds from outpatients with skin and soft-tissue infections (SSTIs) in Wuhan city. Methods A total of 182 MSSA isolates were collected from outpatients with SSTIs in 5 different hospitals in Wuhan city between 2011 and 2013. The Kirby-Bauer′s disk diffusion method was used to evaluate antimicrobial susceptibility of the MSSA isolates, and multiplex PCR was performed to detect mecA and PVL genes in these isolates. Results Of the 182 MSSA isolates, 65 (35.71%) carried PVL genes. The positive rate of PVL genes was significantly different among patients with different diseases (χ2=49.76, P=0.00) , and relatively higher in patients with furuncles/carbuncles (7/7) , folliculitis (3/3) , abscesses (55.53%, 30/57) or impetigo (2/4). The age of patients with PVL-positive MSSA infection was significantly younger than that with PVL-negative MSSA infection (35.40 ± 19.31 years vs. 43.21 ± 20.75 years, t=2.50, P=0.01). Among 65 PVL-positive MSSA isolates, the rate of resistance to clindamycin was highest (87.69%) , followed by that to penicillin (53.85%) and erythromycin (41.54%). The frequency of resistance to clindamycin was highest in 117 PVL-negative MSSA isolates, followed by that to penicillin (20.51%) and ampicillin (12.82%). Furthermore, there was a significant increase in the rate of resistance to penicillin (χ2=21.19) , ampicillin (χ2=97.97) , doxycycline (χ2=11.61) , ciprofloxacin (χ2=8.07) , erythromycin (χ2=25.04) and gentamicin (χ2=10.86) in PVL-positive MSSA isolates compared with PVL-negative MSSA isolates (all P<0.05). Conclusions MSSA isolates from outpatients with SSTIs in Wuhan city are resistant to most β-lactam antibiotics. Flucloxacillin, compound sulfamethoxazole tablets or doxycycline is recommended for empirical treatment of PVL-positive MSSA infections. Key words: Soft tissue infections; Staphylococcus aureus; Microbial sensitivity tests; Panton-Valentine leukocidin; PVL genes