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Introduction Methicillin resistant Staphylococcus aureus (MRSA) is a versatile pathogen capable of causing multitude of human diseases. It is one of the most important nosocomial pathogen that implicated in community and healthcare associated infections. Therefore, this study aims to characterize different SCC mec elements found in MRSA isolates. Moreover, molecular typing was performed to investigate the genetic relatedness among MRSA isolates. Methods Phenotypic identification of MRSA was done by disc diffusion method. The MRSA isolates were typed based on the SCC mec , coa and agr genes. Phenotypic characterization included the detection of biofilm, lipase, protease, lecithinase, staphylokinase and hemagglutination. Also, hla , hlb , hlg , hld , tsst- 1 , psm-mec and mecI genes were detected genotypically. The correlation between the molecular types identified and the profile of virulence factors, clinical and geographical sources was determined for all isolates. Results Eighty five isolates were identified as MRSA. Eight types of SCC mec elements were detected among these isolates. Type V was the most observed type (56.47%). Regarding the correlation between SCC mec types and virulence factors, type V SCC mec exhibited a significant association with biofilm (p < 0.0001), staphylokinase (p = 0.0495) and tsst -1 (p = 0.0498). Molecular typing of coa gave an insight to the presence of specific types in specific hospital wards. Based on agr typing, agr I was the highest prevalent type in MRSA isolates (54.11%). Conclusion There is an increase of MRSA infections particularly the community acquired with high variability in the distribution of virulence factors among different SCC mec types. The association between type III and V SCC mec with certain hospitals may be an evidence of nosocomial infection among these hospitals. [ABSTRACT FROM AUTHOR]

The widespread emergence of methicillin resistant Staphylococcus aureus , as a common cause of nosocomial infections, is becoming a serious concern in global public health. The objective of the present study was to investigate antimicrobial susceptibility pattern, frequency of virulence genes and molecular characteristics of methicillin-resistant Staphylococcus aureus strains isolated from patients with bacteremia. A total of 128 methicillin-resistant Staphylococcus aureus isolates were collected during February 2015 to January 2016. In vitro antimicrobial susceptibility of the isolates was assessed using the disk diffusion method. Conventional PCR was performed for the detection of adhesion ( can , bbp , ebp , fnbB , fnbA , clfB , clfA ) and toxin ( etb , eta , pvl , tst ) encoding genes, determining the agr type, SCC mec , MLST and spa typing of the isolates. All the methicillin-resistant Staphylococcus aureus isolates were found to be sensitive to linezolid, teicoplanin, and vancomycin. Resistance to the tested antibiotics varied from 97.7% for penicillin to 24.2% for mupirocin. The rate of multi drug resistance (MDR) in the present study was 97.7%. The most commonly detected toxin and adhesion genes were tst (58.6%), and clfB (100%), respectively. The majority of SCC mec III isolates were found in agr group I while SCC mec IV and II isolates were distributed among agr group III. Multilocus Sequence Typing (MLST) of the MRSA isolates showed five different sequence types: ST239 (43%), ST22 (39.8%), ST585 (10.9%), ST45 (3.9%) and ST240 (2.3%). All of the pvl positive strains belonged to ST22-SCC mec IV/t790 clone and were MDR. Among different 7 spa types, the most common were t790 (27.3%), t037 (21.9%), and t030 (14.1%). spa types t016, t924 and spa type t383 were reported for the first time from Asia and Iran, respectively. It was shown that spa types circulating in the studied hospitals varied which support the need to perform future surveillance studies in order to understand methicillin-resistant Staphylococcus aureus distribution and thus more effective infection control. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus by producing biofilm and facilitating chronic infection is a common cause of mastitis in cows and thereby can cause food poisoning by production of enterotoxins in milk. The agr typing method is an important tool for epidemiological investigation about S. aureus . The aims of the present study were to detect biofilm related genes, 5 classical enterotoxin genes and the agr types among S. aureus isolates. The ability of S. aureus isolates to produce biofilm was evaluated by modified CRA plate. Six biofilm related adhesion genes ( ica D, ica A, fnb A, bap , clf A and cna ), five classical enterotoxin genes ( sea, seb, sec , sed and see ) and tst -1 gene were detected by PCR methods. Multiplex-PCR was used to determination of the agr groups. 55 out of 80(68.8%) S. aureus isolates were biofilm producer. The ica D gene was detected in 70 (87.5%) of isolates. The prevalence rates of fnb A, ica A, clf A, cna and bap were 72.5, 56.25, 50, 22.5, and 5% respectively. The agr group I and III were detected in 57.5% 25% of studied isolates. The sea , sed and tst -1 genes were found in 10%, 7.5% and 1.25% of isolates respectively. The majority of S. aureus were able to produce biofilm. Significant associations were observed between presence of the ica D, ica A, fnb A, clf A and the cna genes as well as biofilm formation. The present study revealed that isolates with the agr type III are more potent for biofilm production. Our data supported a possible link between the agr types and certain SE genes. [ABSTRACT FROM AUTHOR]

Abstract: The population structure of 111 methicillin-susceptible Staphylococcus aureus (MSSA), recovered in Spain from healthy and risk-free carriers was investigated using pulsed-field gel electrophoresis (PFGE), spa (staphylococcal protein A) typing, multi locus sequence typing (MLST) and the accessory gene regulator (agr). Results from the different techniques were highly concordant, and revealed twelve clonal complexes (CCs): CC30 (27%), CC5 (18.9%), CC45 (16.2%), CC15 (11.7%), CC25 (8.1%), CC1, CC9 (3.6% each), CC59, CC97 and CC121 (2.7% each), CC72 (1.8%) and CC8 (0.9%). Isolates with genetic backgrounds of hospital-acquired MSSA were detected and, consistent with the ability of diverse MSSA to act as recipients of the SCCmec cassette, a MSSA isolate from a healthy carrier shared the ST, spa-type and agr-type of a MRSA clone recovered in a hospital of the same region. All except two fragments of the PGFE-profiles of these isolates were identical, and the differential fragment of the MRSA carried mecA. Analyses of the exotoxin gene content of the nasal isolates revealed an increase in the number of exotoxin genes over time. This, together with the detection of lukPV and the high frequency of tst, exfoliatin and enterotoxin genes, is worrisome and requires further surveillance. [Copyright &y& Elsevier]