Investigation of host risk factors and PVL gene which is one of virulence factors for Staphylococcus aureus grown in nasal smear cultures of patients hospitalized in the intensive care unit

Investigation of Host Risk Factors and PVL Gene which is One of Virulence Factors for Staphylococcus aureus grown in Nasal Smear Cultures of Patients Hospitalized in the Intensive Care UnitAim: We planned to determine the rate, and risk factors for nasal carriership of Staphylococcus aureus, the rate of detection of both Panton-Valentine leukocidin (PVL) gene in S. aureus spp., and also types of staphylococcal cassette cromosome (SCCmec) in MRSA spp. in patients admitted in ICU. To this end, we aimed both to demonstrate PVL gene which is one of the virulence factors for S. aureus isolated from nasal smears obtained from ICU patients within the first 48 hours of their admittance in ICU using polymerase chain reaction, and also investigate host risk factors for S. aureus carriership.Materials and Methods: Two-hundred fifty patients hospitalized in intensive care units of Dokuz Eylul University, Faculty of Medicine during a 9-month period extending from March 1 to November 31, 2011. After obtaining informed consents of the patients? relatives, they were requested to complete a form so as to determine relevant demographic data, and presence of past or current chronic diseases, and pertinent risk factors, and nasal smear samples were obtained from the patients within the first 48 hours of their hospitalization. Identification of S. aureus spp., and their susceptibility to methicilline in compliance with CLSI standards. In all grown S. aureus spp. the presence of lukS-PV and lukF-PV, SCCmec of PVL was looked for using multiplex PCR method.Results: In 42 (16.8%) of 250 patients included in the study, nasal carriership of S. aureus was detected. Only one (0.4%) of these S. aureus spp. was methicillin-resistant Staphylococcus aureus (MRSA). Risk analysis for nasal carriership of S. aureus, revealed that male gender, insulin use, and existence of cirrhosis increased the rate of S. aureus carriership, while tobacco use was found to be a negative risk factor. PVL gene was not observed in none of 42 S. aureus isolates. MRSA strain were SCCmec tip III.Discussion: Many studies performed in our country which also supported our results, have detected lower MRSA colonization rates. Because of lower MRSA rates, and absence of PVL gene in our S. aureus isolates in our study, community- acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections which constitute a serious health problem in USA, and many European countries.do not currently pose a significant public health problem in our country. In planning emprical treatment for community-acquired diseases, we think that these findings should be taken into consideration, and antibiotherapy with glycopeptide, lipopeptide, and oxazolidine group antibacterials should not be used as a first-line therapy.Key words: Staphylococcus aureus; PVL; MRSA; SCCmec