Evaluation of phenotypic and genotypic methods for detection of methicillin - resistant Staphylococcus aureus strains

Abstract

Food-borne  pathogenic  is a group of micro -organis ms that caus e food -borne illnes s thus ,  the  res earch  for  finding  effective  drugs  agains t  this  infection  is  neces s ary. Staphylococcus  aureus is the major caus e of food -borne and nos ocomial infection in las t decade  and  methicillin  res is tant  S.  aureus  (MRSA)  has  emerged  as  a major clinical problem.  The  aim of the pres ent s tudy was to compare different  phenotypic  methods with genotypic method by polymeras e chain reaction (PCR) for the detection of MRSA s trains .   Sens itivity   to   methicillin   was   als o   inves tigated   by   oxacillin,   methicillin, cefotetan,  cefoxitin,  cefmetazole  dis ks ,  the  data  tab, and  dis k diffus ion  method  and oxacillin   s trip.   Minimum   inhibitory   concentration    (MIC)   of   thes e   is olates   was determined  by us ing micro-broth dilution. A total of 186 is olates of S. aureus with PCR method  (gold  s tandard)  were detected. About 95 is olates  were methicillin -s ens itive S. aureus , and  91 is olates  were  MRSA.  Among  the  diagnos tic methods  s tudied, micro - broth  dilution  and  cefoxitin  dis k  had  the  mos t  s pecificity  with  98.9%  and  94.7%, res pectively. The s ens itivity of them was 100.0% and 98.9%, res pectively. Furthermore, the  concordance  with  PCR  was  98.9%  and  93.6%,  res pectively.  The  cefotetan  and cefmetazole  dis ks  had  the  lowes t  concordance  with  the  res ults  of PCR. Due  to  the neces s ity   of   us ing   s imple,  reliable   and   low-cos t  methods   in   routine   diagnos tic laboratories  it  s eems  us e of cefoxitin  dis k s till be cons idered as one of recommended methods for detecting MRSA is olates .