ABSTRACT
Background and Aims: Staphylococcus aureus is one of the important pathogens around the world. The present investigation was carried out to study the distribution of Staphylococcal Cassette Chromosome Mec [SCCmec] types and antibiotic resistance properties in methicillin-resistant Staphylococcus aureus isolated from Isfahan hospitals
Materials and Methods: A total of 250 clinical specimens were collected from three major Isfahan hospitals. The samples were cultured, and biofilm producer isolates were subjected to several polymerase chain reaction methods. The patterns of antibiotic resistance were studied using the disk diffusion method
Results: In the present study, 110 out of 250 samples [44%] were found to be positive for Staphylococcus aureus, and all the isolates produced the biofilm in different levels. The most commonly infected samples were collected from wounds [44.5%]. The incidence of mecA, tetK, ermA, ermC, tetM, aacA-D, linA, msrA, vatA, vatC and vatB antibiotic resistance genes were 93.6%, 34.84%, 28.20%, 29.30%, 21.87%, 18.71%, 9.48%, 8.65%, 7.18%, 4.43% and 3.71%, respectively. The distribution of SCCmec III [42] was found to be the most type out of 103 mec positive strains
Conclusions: In the prsent study, the highest resistance belonged to methicillin [90.2%], erythromycin [89.7%], ciprofloxacin [89.5%] and penicillin [88%] and the lowest resistance was reported for vancomycin [10%] and nitrofurantoin [8%]. These infections with these strains require more advanced hospital care with an emerging demand for the novel antibiotics
ABSTRACT
One of the main mechanisms of resistance to carbapenems is potential of Klebsiella pneumoniae to produce K. pneumoniae Carbapenemase [KPC]. KPC is an important type of Carbapenemase, which can hydrolyze carbapenems and other beta-lactam antibiotics. Modified Hodge Test [MHT] and use of boronic acid as a KPC inhibitor are two types of phenotypic methods, which are used for detection of carbanemase-producing bacteria. Specificity of these two phenotypic tests for identification of KPC was assessed in this study. Forty-four K. pneumoniae strains were isolated from wound infections of burn patients. All isolates were identified with specific biochemical tests. Carbapenem-resistant K. pneumoniae isolates were identified by disc diffusion method and analyzed with cut off-points of CLSI 2011 guideline. For detection of KPC-producing strains, carbapenem-resistant isolates were examined with two different phenotypic [i.e. MHT and Boronic acid] methods. Subsequently, strains with positive phenotypic methods were examined by PCR as a molecular method. Twenty-eight [64%] out of 44 isolates were resistant to carbapenem according to CLSI breakpoints and 16 [36%] were susceptible. MHT was positive in all of carbapenem-resistant isolates but none of them have had the synergism effect between meropenem and boronic acid. Also, all isolates were negative for presence of KPC genes on gel electrophoresis. According to results MHT has not enough specificity for detection of KPC