Molecular Typing of Staphylococcus aureus Isolated From Clinical Specimens During an Eight-Year Period (2005 - 2012) in Tabriz, Iran


Mohammad Ahangarzadeh Rezaee 1 , 2 , 3 , Seyed Foad Mirkarimi 3 , 4 , Alka Hasani 1 , 3 , Vajihe Sheikhalizadeh 3 , Mohammad Hossein Soroush 3 , Babak Abdinia 1 , 5 , *

1 Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, IR Iran

2 Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, IR Iran

3 Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, IR Iran

4 Student Research Committee, Tabriz University of Medical Sciences, Tabriz, IR Iran

5 Medical Education Research Center, Tabriz University Of Medical Sciences,Tabriz, IR Iran

How to Cite: Ahangarzadeh Rezaee M, Mirkarimi S F, Hasani A, Sheikhalizadeh V, Soroush M H, et al. Molecular Typing of <i>Staphylococcus aureus</i> Isolated From Clinical Specimens During an Eight-Year Period (2005 - 2012) in Tabriz, Iran, Arch Pediatr Infect Dis. 2016 4(2): e35563. doi: 10.5812/pedinfect.35563.


Archives of Pediatric Infectious Diseases: 4 (2); e35563
Published Online: March 9, 2016
Article Type: Research Article
Received: December 17, 2015
Revised: January 27, 2016
Accepted: February 2, 2016


Background: Antibiotic resistant Staphylococcus aureus is a serious public health problem worldwide.

Objectives: This study aimed to investigate the susceptibility pattern and molecular typing of S. aureus isolated from clinical specimens of hospitalized patients during eight years, from 2005 to 2012.

Materials and Methods: A total of 151 randomly selected S. aureus isolates, identified with phenotypic tests and detection of nuc gene, were subjected to antimicrobial susceptibility testing using the disk diffusion method. Moreover, molecular typing of the isolates was carried out by PCR-RFLP based on coa and spa genes.

Results: All isolates were susceptible to vancomycin and teicoplanin. High rates of susceptibility were also observed with rifampin (98.1%), imipenem (94.7%), and linezolid (94.1%). On the other hand, most of the isolates were resistant against penicillin (95.4%), erythromycin (68.9%) and clindamycin (57.6%). Four types of spa and coa were distinguished among the isolates based on PCR results; however, the HaeII digestion resulted in a total of sixteen and nine RFLP patterns for spa and coa genes, respectively.

Conclusions: The outcome of this study indicates a higher discriminatory power of the RFLP analysis based on the spa gene compared to the coa gene. Moreover, the results of our study reveal that the resistance rate of S. aureus to some antimicrobial agents including linezolid is a growing concern.

1. Background

Staphylococcus aureus is one of the greatest concerns of all health-care-associated pathogens due to its ability to cause a wide variety of life-threatening infections including endocarditis, food poisoning, toxic shock syndrome, septicemia, skin and soft tissue infections as well as bone infections (1). In addition to the factors involved in the virulence of S. aureus, its resistance to antimicrobials contributes to its role as an effective opportunistic pathogen.

Methicillin resistant S. aureus was reported in 1961 from United Kingdom, shortly after methicillin’s introduction in clinical practice (2). The rate of MRSA infections has increased dramatically since the mid-1980s (3). The surveys of the US association for professionals in infection control and epidemiology, Inc. (APIC) showed that the prevalence of MRSA in 2010 increased to 66.4 per 1000 inpatients compared to 46.3 in 2006 (4). The treatment options of MRSA are limited to few antibiotics like vancomycin, linezolid and tigecycline. Unfortunately, S. aureus isolates with decreased susceptibility to vancomycin (VISA) have recently been reported, which indicates that the data about antibiotic resistance in S. aureus isolates are critical for optimal decisions regarding infection control policies (5). S. aureus is a heterogenous species. Thus, in order to distinguish strains within this species for local epidemiologic or outbreak investigation purposes a highly discriminating genetic marker that accumulates variation rapidly is required (6). The pulse field gel electrophoresis (PFGE) is recognized as the most useful and discriminatory method for typing, but it is relatively difficult to standardize and is more time consuming than PCR-based methods since it requires culturing the bacteria (7). Alternatively, polymerase chain reaction (PCR)-based methods, targeting various genes such as protein A (spa) and coagulase (coa), can provide a rapid amplification, detection and typing tool for S. aureus strains (8, 9).

Nevertheless, there is a lack of data regarding S. aureus molecular types in Iran, particularly the northwestern part, as this could potentially result in transmission and establishment of undetected clones of S. aureus.

2. Objectives

The present study was conducted to perform the molecular characterization of S. aureus clinical isolates in northwest of Iran by evaluation of their antimicrobial susceptibility patterns in addition to molecular typing based on PCR-RFLP of coa and spa genes.

3. Materials and Methods

3.1. Sample Collection and Phenotypic Identification

In this study, the sample population consists of 151 isolates of Staphylococcus aureus which were selected randomly from stock ones isolated during eight years from 2005 to 2012 from various clinical specimens of patients admitted to the four teaching hospitals (Imam Reza, Sina, Shahid Madani and Kodakan) in Tabriz, northwest region of Iran. The isolates were identified as S. aureus based on bacterial growth on mannitol salt agar, colony morphology, gram staining, catalase, slide or tube coagulase and DNase tests (10).

3.2. Antibiotic Susceptibility Test

Antimicrobial profiling was performed by the disk diffusion method. The selection of an antibiotic panel for susceptibility testing is based on clinical and laboratory standards institute guideline (11). All antibiotic discs including penicillin (10 unit), oxacillin (1 μg), vancomycin (30 μg), teicoplanin (30 μg), gentamicin (10 μg), rifampin (5 µg), azithromycin (15 μg), erythromycin (15 μg), clindamycin (15 μg), ceftriaxone (30 μg), ciprofloxacin (5 μg), ofloxacin (5 μg), cotrimoxazole (25 μg), meropenem (10 μg), imipenem (10 μg) and linezolid (30 µg) were prepared from MAST company (Mast diagnostics, UK). Staphylococcus aureus ATCC 29213 was used as a control strain for the susceptibility testing.

3.3. Molecular Speciation and Detection of mecA

All isolates were confirmed as S. aureus by screening for the nuclease-encoding gene (nuc) and for methicillin resistance by mecA gene using a multiplex PCR as described previously (12). Chromosomal DNA was extracted using SDS-proteinase K with the CTAB method as prescribed by Sambrook et al. (13). The S. aureus ATCC 25923 and S. aureus ATCC 33591 strains were used as negative and positive controls for mecA and nuc genes, respectively.

3.4. Polymerase Chain Reaction-RFLP for spa and coa Typing

Based on the published sequences for the spa and the coa genes, the multiplex PCR was applied for amplification of target genes with the following primers: SPA1, 5'-ATC TGG TGG CGT AAC ACC TG-3' and SPA2, 5'-CGC TGC ACC TAA CGC TAA TG-3' (14), COA1:5'-CGA GAC CAA GAT TCA ACA AG-3' and COA2:5'-AAA GAA AAC CAC TCA CAT CAG T-3' (15).

The PCR master mix consisted of 1X PCR buffer, 1 mM MgCl2, 0.2 mM dNTPs (TAKARA, Japan), 1 unit of Taq DNA polymerase (TAKARA, Japan), 1 μM of primers and 5 μL of DNA extract in a final volume of 50 μL.

The PCR conditions were as follows: Initial denaturation at 94°C for 7 minutes followed by 35 cycles of denaturation at 94°C for 1 minute, annealing at 56°C for 1 minute and extension at 72°C for 3 minutes with a final extension at 72°C for 5 minutes.

After amplification of the variable region of spa and coa, 10 μL of each amplicon was mixed and digested with 1 μL of HaeII restriction enzyme (MBI, Fermentas, Lithuania) at 37°C for 3 hours, and fragments were detected by electrophoresis in 1.5% agarose gels and subsequent ethidium bromide staining.

3.5. Statistical Analysis

The data were analyzed using the chi-square test with SPSS software version 22.0 (SPSS Inc., Chicago, Illinois, USA). A statistically significant difference was considered as a P < 0.05.

4. Results

Out of 151 S. aureus identified on the basis of phenotypic tests, all strains were positive for the presence of nuc gene, while mecA gene was detected in 54 (35.7%) isolates (considered as MRSA), and the remaining 97 (64.3%) isolates were identified as methicillin sensitive (MSSA).

Concerning the origin of isolates, Most of the strains [n = 62 (41.1%)] were isolated from wound, followed by blood culture [52 (34.4%)], urine [16 (10.6%)] and the remaining were obtained from specimens like synovial fluid, sputum, intravenous catheter and endotracheal tube.

4.1. Antimicrobial Susceptibility

According to disk diffusion assay, all isolates were uniformly found susceptible to vancomycin and teicoplanin, while few of them showed nonsusceptibility to rifampin (1.9%), imipenem (5.3%), and linezolid (5.9%). However, 95.4% resistance rate was observed to penicillin followed by 68.9% to erythromycin and 57.6% to clindamycin. Table 1 shows the antimicrobial resistance pattern of tested isolates.

Table 1. Antimicrobial Susceptibility Pattern of Tested Staphylococcus aureus Isolates
AntibioticsResistant IsolatesIntermediate Resistant IsolatesSensitive Isolates
Penicillin144 (95.4)-7 (4.6)
Oxacillin52 (34.4)-99 (65.6)
Vancomycin--151 (100)
Teicoplanin--151 (100)
Gentamicin28 (18.5)5 (3.3)118 (78.1)
Rifampin3 (1.9)-148 (98)
Azithromycin37 (24.5)6 (3.9)108 (71.5)
Erythromycin104 (68.9)15 (9.9)32 (21.2)
Clindamycin87 (57.6)17 (11.3)47 (31.1)
Ceftriaxone36 (23.8)-115 (76.5)
Ciprofloxacin16 (10.6)21 (13.9)114 (75.5)
Ofloxacin12 (7.9)2 (1.3)137 (90.7)
Cotrimoxazole31 (20.5)-120 (79.5)
Meropenem8 (5.3)-143 (94.7)
Imipenem9 (5.9)2 (1.3)140 (92.7)
Linezolid9 (5.9)-142 (94)

4.2. Spa and coa Typing

The lengths of spa bands in the isolated bacteria were varied from 1000 to 1450 bp. These patterns were classified as type S1 (1450 bp), S2 (1250 bp), S3 (1100 bp) and S4 (1000 bp) including 36.4%, 32.4%, 23.2% and 8%, respectively. Moreover, spa amplicons, after digestion with HaeII restriction enzyme, showed distinct spa banding patterns. The restriction patterns of spa gene are shown in Table 2.

Regarding coa typing of all isolates, four distinct types were defined. These types were designated as C1 - C4 with fragments ranged from 500 to 900 bp. As shown in Table 2HaeII digestion of these PCR products yielded two (in the cases of C1, C2 and C4 types) or 3 (in C3 type) different restriction profiles.

Table 2. Pattern of spa and coa Genes Diversity Among Staphylococcus aureus Isolates
TypesPCR Amplicon Size, bpNo. (%)RFLP Pattern, bpNo. (%)
S1145055 (36.4%)
S1a250, 12005 (3.3)
S1b250, 500, 65035 (23.2)
S1c300, 11004 (2.6)
S1d200, 500, 7502 (1.3)
S1e600, 8006 (4)
S1f150, 500, 8003 (2)
S2125049 (32.4%)
S2a350, 90020 (13.2)
S2b400, 80015 (9.9)
S2c125014 (9.3)
S3110035 (23.2)
S3a200, 300, 6009 (6)
S3b400, 7003 (2)
S3c600, 50022 (14.6)
S3d300, 7501 (1)
S4100012 (8)
S4a350, 6003 (2)
S4b300, 7003 (2)
S4c450, 5006 (4)
C150046 (31.5%)
C1a50022 (14.5)
C1b400,10013 (8.5)
C260019 (12.6)
C2a200, 40014 (9)
C2b6005 (3)
C370053 (35)
C3a250, 35013 (8.5)
C3b200, 300,18024 (16)
C3c70017 (11)
C490033 (22)
C4a400, 45019 (12.7)
C4b300, 60014 (9)

5. Discussion

Staphylococcus aureus has always been a stumbling block for antimicrobial chemotherapy and the introduction of new classes of antimicrobial agents is usually followed by the emergence of resistant forms of this pathogen (16). Moreover, infections caused by S. aureus have a poorer prognosis when the infecting strain is MRSA (17). A lot of studies in developing countries demonstrate a continuing increase in MRSA infections (18, 19). The increasing incidence of MRSA infections most likely reflects the growing impact of medical interventions, devices, as well as antibiotic overusing, older age and comorbidities of patients (20). The prevalence of MRSA in the present study was 35.7%, which is comparable to that found by Fatholahzadeh et al. in Iran and Dar et al. in India (21, 22). However, this rate is less than half of the percentage reported in the other studies from Iran (23, 24). This observed difference could be attributed to the period of our study that was longer than others. Moreover, concerning the isolation time of bacteria in the current study, beginning since 2003, and considering the growing rates of MRSA over the years, the fairly low percentage of MRSA in our study is justifiable.

In the present study, according to PCR and disk diffusion results, we have detected two S. aureus isolates positive for mecA gene but susceptible to oxacillin disk. The occurrence of these variants could be explained by the presence of complete regulator genes (mecI and/or mecRI), as described previously (25). Only a low proportion of isolates in our study presented susceptibility to penicillin. It was expected, since, currently, it has been recognized that only a small percentage of S. aureus clinical isolates are not β-lactamase producer (26). Linezolid resistance shown by 5.9% of S. aureus isolates in the present study is one of the significant and clinical relevant observations, as there are several studies from Iran and other countries reported that almost all of clinical strains of S. aureus still remained susceptible to linezolid (27-30). Indeed, linezolid is the first representative of a new synthetic class of antibacterial oxazolidinones, which inhibits bacterial protein synthesis in a different mode from that of other protein synthetic inhibitors at the chain elongation step (31). Researchers assumed that resistance to linezolid would never develop. However, linezolid-resistant S. aureus appeared within 1 year after linezolid was approved for therapeutic use (32).

In agreement to most earlier reports (21, 27, 33, 34) vancomycin and teicoplanin resistance were not observed among our isolates which indicate that vancomycin is still the drug of choice for the treatment of life-threatening infections of S. aureus, although recently isolation of vancomycin resistant S. aureus from some countries has confirmed that emergence of these strains is a global issue (34, 35). Furthermore, it should be noted that the disk diffusion agar test did not accurately identify resistance to vancomycin in S. aureus and broth or agar dilution methods or E-test are needed (36).

Understanding the molecular characteristics of S. aureus isolates is important for assessing the relatedness of isolates, and consequently, for the implementation of appropriate infection control measures (37).

The spa and coa genes in S. aureus isolates have various numbers of degenerate repeats, which are clearly polymorphic in both number and sequence (38). Thus, both the spa and coa typing methods have been reported to provide a rapid, inexpensive and appropriate method for the genotyping of S. aureus strains in epidemiological studies (39). The spa method is based on the amplification of the protein A mediating gene (spa gene), which generates a staphylococcal strain-specific amplification pattern and can be used for typing of S. aureus strains. For example, Luxner et al. could classify clinical isolates of S. aureus in 64 groups using spa typing (40). In the present study, the spa gene length were varied from 1000 to 1450 bp among tested isolates, which are very close to the previously reported range (1150 to 1420 bp) from India (14). Moreover, based on the polymorphism of the spa gene, we could classify isolates into four different types and in this respect our results are similar to another report from Iran (41). S1 (1450 bp) and S2 (1250 bp) types were the most frequent types among all types. In addition, S1 type yielded six restriction patterns after digestion with HaeII. Whereas, S2 type yielded three RFLP patterns indicates that S1 type has a greater genetic diversity than type S2. As a result, distinct genetic diversity may exist even between predominant types. Restriction profile analysis of the spa gene in all our isolates demonstrated 16 different patterns, which is more than those reported by Mitani et al. in Japan (42). They could determine eight restriction pattern of spa, as well as four pattern of the coa gene. Beside of spa typing, classification based on the coa gene has also been considered a simple and accurate method for molecular typing of S. aureus (43). In our study, PCR amplification of the coa gene resulted in identification of four different types and type C3 (with 700 bp length) as the most frequent type. The polymorphism of this gene is due to repetitions of 3' elements of the coa gene in various strains (44). Previously published data from Iran have shown the presence of different coa types (45, 46). Talebi-Satlou et al. conducted a similar study on S. aureus isolates associated with skin and urinary tract infections in Urmia region of Iran, and showed four coa types with 410, 530, 700 and 790 bp length (45). They also reported the coa type with 700 bp as the most common type, which is consistent with our results. However, in contrast to their study that determined two RFLP patterns for the dominant coa type, we could classified the predominant coa type in three subtypes, which indicate great heterogeneity among our isolates. It is noteworthy that, the coa type with 700 bp length also was reported as a dominant type in another study from Iran (47). Considering this finding, it maybe suggested that a specific subset of S. aureus strain is well- adapted in various parts of human body in different region of Iran. However, expanded genetic analyses are necessary to generate more evidence for this finding.

Overall, we could classify 151 clinical isolates of S. aureus in 16 and 9 diverse restriction types based on PCR-PFLP of spa and coa genes, respectively, which indicate higher discriminatory power of spa typing compared to coa typing.

Finally, the outcome of our study shows that spa typing can be used along with other molecular methods as an appropriate method in epidemiological investigations to control and monitor infections obtained from hospitals and society, in distinguishing S. aureus isolates collected from clinical specimens.




  • 1.

    Makgotlho PE, Kock MM, Hoosen A, Lekalakala R, Omar S, Dove M, et al. Molecular identification and genotyping of MRSA isolates. FEMS Immunol Med Microbiol. 2009; 57(2) : 104 -15 [DOI][PubMed]

  • 2.

    Enright MC, Robinson DA, Randle G, Feil EJ, Grundmann H, Spratt BG. The evolutionary history of methicillin-resistant Staphylococcus aureus (MRSA). Proc Natl Acad Sci . 2002; 99(11) : 7687 -92 [DOI]

  • 3.

    Miller MB, Weber DJ, Goodrich JS, Popowitch EB, Poe MD, Nyugen V, et al. Prevalence and Risk Factor Analysis for Methicillin-Resistant Staphylococcus aureus Nasal Colonization in Children Attending Child Care Centers. Iran J Med Microbiol. 2010; 49(3) : 1041 -7 [DOI]

  • 4.

    Jarvis WR, Jarvis AA, Chinn RY. National prevalence of methicillin-resistant Staphylococcus aureus in inpatients at United States health care facilities, 2010. Am J Infect Control. 2012; 40(3) : 194 -200 [DOI][PubMed]

  • 5.

    Shittu AO, Lin J. BMC Infectious Diseases. 2006; 6(1) : 125 [DOI]

  • 6.

    Koreen L, Ramaswamy SV, Graviss EA, Naidich S, Musser JM, Kreiswirth BN. spa typing method for discriminating among Staphylococcus aureus isolates: implications for use of a single marker to detect genetic micro- and macrovariation. J Clin Microbiol. 2004; 42(2) : 792 -9 [PubMed]

  • 7.

    Senna JP, Pinto CA, Carvalho LP, Santos DS. Comparison of pulsed-field gel electrophoresis and PCR analysis of polymorphisms on the mec hypervariable region for typing methicillin-resistant Staphylococcus aureus. J Clin Microbiol. 2002; 40(6) : 2254 -6 [PubMed]

  • 8.

    Frenay HM, Bunschoten AE, Schouls LM, van Leeuwen WJ, Vandenbroucke-Grauls CM, Verhoef J, et al. Molecular typing of methicillin-resistant Staphylococcus aureus on the basis of protein A gene polymorphism. Eur J Clin Microbiol Infect Dis. 1996; 15(1) : 60 -4 [PubMed]

  • 9.

    Ishino K, Tsuchizaki N, Ishikawa J, Hotta K. Usefulness of PCR-restriction fragment length polymorphism typing of the coagulase gene to discriminate arbekacin-resistant methicillin-resistant Staphylococcus aureus strains. J Clin Microbiol. 2007; 45(2) : 607 -9 [DOI][PubMed]

  • 10.

    Bannerman TL, Peacock SJ, Murray PR, Baron EJ, Jorgensen JH, Landry ML, et al. Staphylococcus, Micrococcus, and other catalase-positive cocci. J Clin Microbiol. 2006; (Ed. 9) : 390 -411

  • 11.

    Cockerill FR. Performance standards for antimicrobial susceptibility testing: twenty-second informational supplement;[... provides updated tables for... M02-A11 and M07-A9]. 2012;

  • 12.

    Fateh Amirkhiz M, Ahangarzadeh Rezaee M, Hasani A, Aghazadeh M, Naghili B. SCCmec Typing of Methicillin-Resistant Staphylococcus aureus: An Eight Year Experience. J Ped Infect Dis. 2015; 3(4)[DOI]

  • 13.

    Sambrook J, Russell D. Molecular Cloning: A Laboratory Manual . 2001 2001;

  • 14.

    Mehndiratta PL, Bhalla P, Ahmed A, Sharma YD. Molecular typing of methicillin-resistant Staphylococcus aureus strains by PCR-RFLP of SPA gene: a reference laboratory perspective. Indian J Med Microbiol. 2009; 27(2) : 116 -22 [DOI][PubMed]

  • 15.

    Goh SH, Byrne SK, Zhang JL, Chow AW. Molecular typing of Staphylococcus aureus on the basis of coagulase gene polymorphisms. J Clin Microbiol. 1992; 30(7) : 1642 -5 [PubMed]

  • 16.

    Kim HB, Jang HC, Nam HJ, Lee YS, Kim BS, Park WB, et al. In vitro activities of 28 antimicrobial agents against Staphylococcus aureus isolates from tertiary-care hospitals in Korea: a nationwide survey. Antimicrob Agents Chemother. 2004; 48(4) : 1124 -7 [PubMed]

  • 17.

    Cosgrove SE, Sakoulas G, Perencevich EN, Schwaber MJ, Karchmer AW, Carmeli Y. Comparison of mortality associated with methicillin-resistant and methicillin-susceptible Staphylococcus aureus bacteremia: a meta-analysis. Clin Infect Dis. 2003; 36(1) : 53 -9 [DOI][PubMed]

  • 18.

    Lescure FX, Biendo M, Douadi Y, Schmit JL, Eveillard M. Changing epidemiology of methicillin-resistant Staphylococcus aureus and effects on cross-transmission in a teaching hospital. Eur J Clin Microbiol Infect Dis. 2006; 25(3) : 205 -7 [DOI][PubMed]

  • 19.

    Ahmad MK, Asrar A. Prevalence of methicillin resistant Staphylococcus aureus in pyogenic community and hospital acquired skin and soft tissues infections. J Pak Med Assoc. 2014; 64(8) : 892 -5 [PubMed]

  • 20.

    Boucher HW, Corey GR. Epidemiology of methicillin-resistant Staphylococcus aureus. Clin Infect Dis. 2008; 46 Suppl 5 : S344 -9 [DOI][PubMed]

  • 21.

    Fatholahzadeh B, Emaneini M, Gilbert G, Udo E, Aligholi M, Modarressi MH, et al. Staphylococcal cassette chromosome mec (SCCmec) analysis and antimicrobial susceptibility patterns of methicillin-resistant Staphylococcus aureus (MRSA) isolates in Tehran, Iran. Microb Drug Resist. 2008; 14(3) : 217 -20 [DOI][PubMed]

  • 22.

    Dar JA, Thoker MA, Khan JA, Ali A, Khan MA, Rizwan M, et al. Molecular epidemiology of clinical and carrier strains of methicillin resistant Staphylococcus aureus (MRSA) in the hospital settings of north India. Ann Clin Microbiol Antimicrob. 2006; 5 : 22 [DOI][PubMed]

  • 23.

    Khosravi AD, Hoveizavi H, Farshadzadeh Z. The prevalence of genes encoding leukocidins in Staphylococcus aureus strains resistant and sensitive to methicillin isolated from burn patients in Taleghani Hospital, Ahvaz, Iran. Burns. 2012; 38(2) : 247 -51 [DOI][PubMed]

  • 24.

    Malihe H. Detection of the antibiotic resistance genes in Staphylococcus aureus isolated from human infections and bovine mastitis. AJMR. 2011; 5(31)[DOI]

  • 25.

    Chambers HF. Methicillin resistance in staphylococci: molecular and biochemical basis and clinical implications. Clin Microbiol Rev. 1997; 10(4) : 781 -91 [PubMed]

  • 26.

    Hoerlle JL, Brandelli A. Antimicrobial resistance of Staphylococcus aureus isolated from the intensive care unit of a general hospital in southern Brazil. J Infect Dev Ctries. 2009; 3(7) : 504 -10 [PubMed]

  • 27.

    Fatholahzadeh B, Emaneini M, Aligholi M, Gilbert G, Taherikalani M, Jonaidi N, et al. Molecular characterization of methicillin-resistant Staphylococcus aureus clones from a teaching hospital in Tehran. Jpn J Infect Dis. 2009; 62(4) : 309 -11 [PubMed]

  • 28.

    Van Griethuysen A, Van 't Veen A, Buiting A, Walsh T, Kluytmans J. High percentage of methicillin-resistant Staphylococcus aureus isolates with reduced susceptibility to glycopeptides in The Netherlands. J Clin Microbiol. 2003; 41(6) : 2487 -91 [PubMed]

  • 29.

    Jevitt LA, Smith AJ, Williams PP, Raney PM, McGowan JJ, Tenover FC. In vitro activities of Daptomycin, Linezolid, and Quinupristin-Dalfopristin against a challenge panel of Staphylococci and Enterococci, including vancomycin-intermediate staphylococcus aureus and vancomycin-resistant Enterococcus faecium. Microb Drug Resist. 2003; 9(4) : 389 -93 [DOI][PubMed]

  • 30.

    Kaleem F, Usman J, Hassan A, Omair M, Khalid A, Uddin R. Sensitivity pattern of methicillin resistant Staphylococcus aureus isolated from patients admitted in a tertiary care hospital of Pakistan. Iran J Microbiol. 2010; 2(3) : 143 -6 [PubMed]

  • 31.

    Li JZ, Willke RJ, Rittenhouse BE, Rybak MJ. Effect of linezolid versus vancomycin on length of hospital stay in patients with complicated skin and soft tissue infections caused by known or suspected methicillin-resistant staphylococci: results from a randomized clinical trial. Surg Infect (Larchmt). 2003; 4(1) : 57 -70 [DOI][PubMed]

  • 32.

    Tsiodras S, Gold HS, Sakoulas G, Eliopoulos GM, Wennersten C, Venkataraman L, et al. Linezolid resistance in a clinical isolate of Staphylococcus aureus. Lancet. 2001; 358(9277) : 207 -8 [DOI][PubMed]

  • 33.

    Mahmood K, Tahir M, Jameel T, Ziauddin A, Aslam HF. Incidence of Methicillin-resistant Staphylococcus aureus (MRSA) causing nosocomial infection in a Tertiary Care Hospital. Annals of King Edward. 2010; 16(2)

  • 34.

    Tiwari HK, Sen MR. Emergence of vancomycin resistant Staphylococcus aureus (VRSA) from a tertiary care hospital from northern part of India. BMC Infect Dis. 2006; 6 : 156 [DOI][PubMed]

  • 35.

    Centers for Disease C. Vancomycin-resistant Staphylococcus aureus--New York, 2004. MMWR Morb Mortal Wkly Rep. 2004; 53(15) : 322 -3 [PubMed]

  • 36.

    Appelbaum PC. Reduced glycopeptide susceptibility in methicillin-resistant Staphylococcus aureus (MRSA). Int J Antimicrob Agents. 2007; 30(5) : 398 -408 [DOI][PubMed]

  • 37.

    Wichelhaus TA, Hunfeld KP, Boddinghaus B, Kraiczy P, Schafer V, Brade V. Rapid molecular typing of methicillin-resistant Staphylococcus aureus by PCR-RFLP. Infect Control Hosp Epidemiol. 2001; 22(5) : 294 -8 [DOI][PubMed]

  • 38.

    van Belkum A, van Leeuwen W, Kaufmann ME, Cookson B, Forey F, Etienne J, et al. Assessment of resolution and intercenter reproducibility of results of genotyping Staphylococcus aureus by pulsed-field gel electrophoresis of SmaI macrorestriction fragments: a multicenter study. J Clin Microbiol. 1998; 36(6) : 1653 -9 [PubMed]

  • 39.

    Mehndiratta PL, Bhalla P. Typing of Methicillin resistant Staphylococcus aureus: a technical review. Indian J Med Microbiol. 2012; 30(1) : 16 -23 [DOI][PubMed]

  • 40.

    Luxner J, Zarfel G, Johler S, Feierl G, Leitner E, Hoenigl M, et al. Genetic characterization of Staphylococcus aureus isolates causing bloodstream infections in Austria. Diagn Microbiol Infect Dis. 2014; 78(2) : 153 -6 [DOI][PubMed]

  • 41.

    Japoni-Nejad A, Rezazadeh M, Kazemian H, Fardmousavi N, van Belkum A, Ghaznavi-Rad E. Molecular characterization of the first community-acquired methicillin-resistant Staphylococcus aureus strains from Central Iran. Int J Infect Dis. 2013; 17(11) : e949 -54 [DOI][PubMed]

  • 42.

    Mitani N, Koizumi A, Sano R, Masutani T, Murakawa K, Mikasa K, et al. Molecular typing of methicillin-resistant Staphylococcus aureus by PCR-RFLP and its usefulness in an epidemiological study of an outbreak. Jpn J Infect Dis. 2005; 58(4) : 250 -2 [PubMed]

  • 43.

    Rodrigues da Silva E, da Silva N. Coagulase gene typing of Staphylococcus aureus isolated from cows with mastitis in southeastern Brazil. Can J Vet Res. 2005; 69(4) : 260 -4 [PubMed]

  • 44.

    Mellmann A, Friedrich AW, Rosenkotter N, Rothganger J, Karch H, Reintjes R, et al. Automated DNA sequence-based early warning system for the detection of methicillin-resistant Staphylococcus aureus outbreaks. PLoS Med. 2006; 3(3)[DOI][PubMed]

  • 45.

    Talebi-Satlou R, Ahmadi M, Dastmalchi Saei H. Restriction Fragment Length Polymorphism Genotyping of Human Staphylococcus aureus Isolates From Two Hospitals in Urmia Region of Iran Using the coa Gene. JJM. 2012; 5(2) : 416 -20 [DOI]

  • 46.

    Momtaz H, Tajbakhsh E, Rahimi E, Momeni M. Coagulase gene polymorphism of Staphylococcus aureus isolated from clinical and sub-clinical bovine mastitis in Isfahan and Chaharmahal va Bakhtiari provinces of Iran. Comp Clin Path. 2011; 20(5) : 519 -22 [DOI][PubMed]

  • 47.

    Afrough P, Pourmand MR, Sarajian AA, Saki M, Saremy S. Molecular Investigation of Staphylococcus aureus, coa and spa Genes in Ahvaz Hospitals, Staff Nose Compared With Patients Clinical Samples. JJM. 2013; [DOI]

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