Investigation of the presence of pantone-valentine leukocidin in staphylococcus aureus strainsısolated from orthopedic surgical site ınfections

Abstract

Staphylococcus aureus is one of the most clinically important bacteria causing infection in humans. It is an important pathogen in surgical site infections (SSIs), especially after orthopedic surgery. Pantone-valentine leukocidin (PVL) has a great importance in the virulence of S.aureus because it can destroy polymorphonuclear cells by necrosis or apoptosis. The spread of PVL positive S.aureus is a great concern, since it may become an important factor for increased morbidity and mortality in SSIs, especially after surgery. In this study, we aimed to investigate the presence of PVL in S.aureus strains isolated from patients who had surgical site infections after orthopedic surgery, and also the clinical status of these patients. Between 2013 and 2017, 101 patients who had SSIs due to S.aureus after orthopedic surgery were included in the study. Identification of the strains was determined by conventional methods and "Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry" (MALDI-TOF MS). Methicillin resistance was determined by Kirby-Bauer disc diffusion method and automated system (Vitek 2, bioMerieux, France). The PVL gene region was investigated by polymerase chain reaction (PCR) method by using the primers Luk-PV-1 and Luk-PV-2. The duration of the patients' hospitalization, C-reactive protein (CRP) and sedimentation levels and clinical status were obtained from the hospital information system, retrospectively. Fifteen (14.9%) of the isolates were methicillin resistance S.aureus (MRSA) and 86 (85.1%) were methicillin susceptibility S.aureus (MSSA). PVL positivity was detected in 14 (13.9%) isolates (3 MRSA, 11 MSSA). The mean hospital stays in PVL-negative patients were 17 (5-73) days and 46 (21-103) days in PVL-positive patients. It was observed that the serologic markers CRP and sedimentation were between 5-7 and 40-60 in PVL negative patients, and between 11-20 and 90-110 in PVL positive patients, respectively. In PVL-negative patients, serologic markers improved in 7-10 days, while in PVL-positive patients they were improved in 17-32 days. Osteomyelitis occurred in six patients (2 PVL positive MRSA, 1 PVL positive MSSA and 3 PVL negative MRSA). In two of the patients who have developed osteomyelitis with PVL-positive MRSA, PVL gene positive S.aureus isolates were observed in their orthopedic SSIs. We also determined that these isolates increased the hospitalization days, improvement time of serological markers and mortality. It is worrisome to isolate PVL-positive S.aureus strains in SSIs. Therefore, we believe that it would be useful to take infection control measures to prevent the spread of these strains in the hospital setting.