Staphylococcal Cassette Chromosome mec (SCCmec) typing and role of SCCmec in resistance to the tetracycline in Staphylococcus isolated from clinical samples in Shiraz

BACKGROUND AND OBJECTIVESThe human pathogen Staphylococcus isolates are the most common pathogen that causes hospital and community acquired infections. Studying on drug resistance, it is important strategy to prevent these types of infections. The use of molecular typing methods is essential for determining the origin of the strains and also in epidemiological investigations. This study aimed to evaluate the different SCCmec types among staphylococcal clinical isolates, and determination of the relationship between SCCmec typing and molecular resistance to tetracycline.MATERIALS AND METHODSThis cross-sectional study was carried out on a total of ۹۳ staphylococcal isolates collected from clinical specimens from Shiraz. Antibiotic susceptibility profiles were identified by agar disc diffusion method according to CLSI guidelines. Bacterial DNA was extracted by using the phenol-chloroform extraction method. The genotypes of SCCmec in the isolates were determined by PCR and the results were analyzed using the chi-square. Strains isolated were tested by PCR to determine the frequency of mec gene, SCCmec types and genes coding for antibiotic resistance.RESULTS AND DISCUSSIONOut of ۹۳ samples, ۲۶ samples (۲۷.۹%) were infected with coagulase positive Staphylococcus aureus, and ۶۷ samples (۷۲.۱%) were infected with coagulase negative Staphylococcus strains.Assigned SCCmec types by PCR revealed SCCmec type II was predominant type with (۶۰%) samples and followed by SCCmec types I (۴۹%), IVa (۴۲.۸%), V (۴۲.۸%), IVc (۴۱.۳%), IVb (۳۹.۷%), IVd (۳۹.۷%), and III (۳۸%). Results of antibacterial susceptibility tests for Staphylococcus isolates shown that ۱۵ (۵۷.۷%) of Staphylococcus aureus and ۴۱ (۶۱.۲%) of coagulase negative Staphylococcus isolates were resistance to tetracycline. Also the significant differences between SCCmec type II with other types was observed.CONCLUSIONA mobile genetic element, staphylococcal cassette chromosome mec (SCCmec), plays an important role in staphylococci pathogenesis. Our findings show that clinical isolates of Staphylococcus carrying various types of SCCmec types. The frequency of isolates containing type II in the current study can indicate an emergence of this SCCmec type in the studied medical centers.