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MRSA from Santa Catarina State, Southern Brazil: intriguing epidemiological differences compared to other Brazilian regions

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most frequently isolated agents in both nosocomial and community settings. It is a constant challenge for antibacterial therapy. Therefore, it becomes essential to understand the epidemiology of MRSA isolates in the institution and/or region to guide empirical therapy. The objective of this study was to evaluate the epidemiological characteristics of MRSA isolates in the state of Santa Catarina, Brazil, and determine if there is a clonal spread. We evaluated 124 clinical isolates of MRSA obtained from various anatomical sites from patients in the state of Santa Catarina in Southern Brazil. The antimicrobial susceptibility profile was evaluated by disk diffusion and minimum inhibitory concentration (MIC) was determined by Etest and broth macrodilution. SCCmec types were determined by multiplex PCR and the clonal relationship among isolates was assessed by pulsed field gel electrophoresis. Antimicrobials that have demonstrated lower rates of resistance were tetracycline (20.2%), sulfamethoxazole-trimethoprim (20.2%) and chloramphenicol (12.9%). We did not detect any resistance to glycopeptides, daptomycin, linezolid, and tigecycline. SCCmec type III was predominant (54%), followed by type II (21.8%), consistent with other Brazilian studies. Twenty-six clones were observed grouping 72 (58%) isolates and no clonal relationship was observed between our isolates and the major epidemic clones circulating in Brazil. An intriguing distinct MRSA epidemiology was observed in Santa Catarina, compared to other Brazilian regions.

Antimicrobial resistance; Vancomycin; Oxacillin


Introduction

Staphylococcus aureus is a major agent of community-acquired infections and healthcare associated infections. A multicenter study among Brazilian hospitals during 2005-2008 found that S. aureus was the main agent of bloodstream infections (20.2%) and infections of the skin and soft tissue (28.1%) and the second most common agent in pneumonia of hospitalized patients (24.9%). Of these infections, approximately 30% were resistant to methicillin (MRSA).1Gales AC, Sader HS, Ribeiro J, Zoccoli C, Barth A, Pignatari AC. Antimicrobial susceptibility of gram-positive bacteria isolated in Brazilian Hospitals Participatingin the SENTRY Program (2005-2008). Braz J Infect Dis. 2009;13:90-8.

Staphylococci become resistant to methicillin by changing transpeptidases in the wall, called penicillin-binding proteins (PBPs), and lose affinity for all β-lactam agents. This information is contained in the mecA gene responsible for encoding an altered PBP (PBP2a).2Otto M. MRSA virulence and spread. Cell Microbiol. 2012;14:1513-21. , 3Koyama N, Inokoshi J, Tomoda H. Anti-infectious agents against MRSA. Molecules. 2013;18:204-24.

Until the early 1990s, MRSA isolates were restricted to hospitals. Currently, however, MRSA is no longer exclusively associated with healthcare infections. During this period, increase in community-acquired MRSA (CA-MRSA) among patients without assignable risk factors for acquiring MRSA was observed (i.e., had no direct or indirect contact with health services that could associate the MRSA infection with health care).4Herold BC, Immergluck LC, Maranan MC, et al. Community-acquired methicillin resistant Staphylococcus aureus in children with no identified predisposing risk. JAMA. 1998;279:593-8.

Since then, a reverse phenomenon began to occur: community isolates, once characterized by the presence of a staphylococcal cassette chromosome (SCCmec) type IV, began to be isolated in hospital settings and those types that were typically isolated in the hospital began to appear in outpatients.5Figueiredo AMS, Ferreira FA. The multifaceted resources and microevolution of the successful human and animal pathogen methicillin-resistant Staphylococcus aureus. Mem Inst Oswaldo Cruz. 2014;109:1-14. , 6Shore AC, Coleman DC. Staphylococcal cassette chromossome mec: recents advances and new insights. Int J Med Microbiol. 2013;303:350-9.

As the epidemiology of MRSA proved to be dynamic, it is important to generate data to better understand the evolution of this epidemiological behavior and to assess its impact on clinical settings.7Yamaki J, Lee M, Shriner KA, Wong-Beringer A. Can clinical and molecular epidemiologic parameters guide empiric treatment with vancomyc informe thicillin-resistant Staphylococcus aureus infections? Diagn Microbiol Infect Dis. 2011;70:124-30. Santa Catarina State has an intriguing low prevalence of MRSA compared to other Brazilian States and understand this epidemiological dynamics would be valuable.

The objective of this study was to evaluate the epidemiological characteristics of MRSA isolates in the state of Santa Catarina.

Methods

Bacterial samples

We used 124 clinical MRSA isolates obtained from various anatomical sites from patients attended in two cities (Blumenau and Florianopolis), located in the State of Santa Catarina, Southern Brazil. Samples were collected from November 2009 through February 2013. One isolate per patient was considered. Samples were selected by convenience. Identification was done using standardized phenotypic methodology8 and isolates were maintained frozen (−20◦ C) in skim milk (DIFCO(r)) plus 10% glycerol.

Antimicrobial susceptibility testing

Antimicrobial susceptibility testing was performed using the disk diffusion method, according to the recommendations and interpretative criteria of the Clinical and Laboratory Standards Institute9Clinical and Laboratory Standards Institute (CLSI). Performance standards for antimicrobial susceptibility testing. Seventeenth Informational Supplement, CLSI document M100-S23. Wayne, PA: Clinical Laboratory and Standards Institute; 2013. and European Committee on Antimicrobial Susceptibility Testing (to tygecycline only).1010. European Committee on Antimicrobial Susceptibility Testing (EUCAST). Breakpoint tables for interpretation of MICs and zone diameters. Version 3.0; 2013.The antimicrobials tested were gentamicin (10 µg), ciprofloxacin (5 µg), erythromycin (15 µg), clindamycin (2 µg), trimethoprim/sulfamethoxazole (1.25 µg/23.75 µg), chloramphenicol (30 µg), tetracycline (30 µg), teicoplanin (30 µg), tigecycline (10 µg), and linezolid (30 µg). MRSA was characterized using the cefoxitin disk (30 µg), and confirmed by PCR for the gene mecA.11 To detect β-lactamase production, we used nitrocefin disk (BD BBLTM DrySlideTM Nitrocefin), using bacterial suspensions in physiological saline. S. aureus ATCC 29213 was used as a positive control, and S. aureus ATCC 25923 was used as a negative control.

MIC determination

Vancomycin MICs were determined by macrodilution method9Clinical and Laboratory Standards Institute (CLSI). Performance standards for antimicrobial susceptibility testing. Seventeenth Informational Supplement, CLSI document M100-S23. Wayne, PA: Clinical Laboratory and Standards Institute; 2013. and by Etest(r) (BioMérieux, Marcy l'Etoile, France) following CLSI interpretative criteria9Clinical and Laboratory Standards Institute (CLSI). Performance standards for antimicrobial susceptibility testing. Seventeenth Informational Supplement, CLSI document M100-S23. Wayne, PA: Clinical Laboratory and Standards Institute; 2013. and the manufacturer's instructions, respectively. MICs for teicoplanin and daptomycin were determined by Etest(r). S. aureus strains ATCC 29213 (MSSA), ATCC 43300 (MRSA), ATCC 700698 (hVISA) and ATCC 700699 (VISA) were used for quality control.

Multiplex PCR

The SCCmec type was determined using the multiplex PCR method according to the protocol developed by Zhang et al.1212 Zhang K, McClure JA, Elsayed S, Louie T, Conly JM. Novel multiplex PCR assay for characterization and concomitant subtyping of staphylococcal cassette chromosome mec types I to V in methicillin-resistant Staphylococcus aureus. J Clin Microbiol. 2003;43:5026-33. The amplicons that were formed had the following sizes: I (613 bp), II (398 bp), III (280 bp), IVa (776 bp), IVb (493 bp), IVc (200 bp), IVd (881 bp), and V (325 bp).1212 Zhang K, McClure JA, Elsayed S, Louie T, Conly JM. Novel multiplex PCR assay for characterization and concomitant subtyping of staphylococcal cassette chromosome mec types I to V in methicillin-resistant Staphylococcus aureus. J Clin Microbiol. 2003;43:5026-33. , 1313 Oliveira DC, Lencastre H. Multiplex PCR strategy for rapid identification of structural types and variants of the mec element in methicillin-resistant Staphylococcus aureus. Antimicrob Agents Chemother. 2002;46:2155-61.

For isolates presenting phenotypic inducible resistance to clindamycin, erm gene was assessed by a multiplex PCR protocol, described elsewhere.1414 Khan SA, Nawaz MS,Khan AA, Cerniglia CE. Simultaneous detection of erythromycin-resistant methylase genes ermA and ermC from Staphylococcus spp. By multiplex-PCR. Mol Cell Probes. 1999;13:381-7. The PCR product (610 bp for ermA and 520 bp for ermC) was analyzed by electrophoresis through a 1.5% agarose gel.1414 Khan SA, Nawaz MS,Khan AA, Cerniglia CE. Simultaneous detection of erythromycin-resistant methylase genes ermA and ermC from Staphylococcus spp. By multiplex-PCR. Mol Cell Probes. 1999;13:381-7. , 1515 Lina G, Quaglia A, Reverdy ME, Leclercq R, Vandenesch F, Etienne J. Distribution of genes encoding resistance to macrolides, lincosamides, and streptogramins among Staphylococci. Antimicrob Agents Chemother. 1999;43:1062-6.

Pulsed-field gel electrophoresis (PFGE)

PFGE was performed according to McDougal et al.1616 McDougal LK, Steward CD, Killgore GE, Chaitram JM, McCallister SK, Tenover FC. Pulsed-field gel electrophoresis typing of oxacillin-resistant Staphylococcus aureus isolates from the United States: establishing a national database. J Clin Microbiol. 2003;41:5113-20. and Pinto et al.1717 Pinto TCA, Souza ARV, D Pina SECM, et al. Optochin-Resistant Streptococcus pneumoniae: Phenotypic and Molecular Characterization of Isolates from Brazil with Description of Five Novel Mutations in the atpC Gene. J Clin Microbiol. 2013;51:3242-9. The fragments were subjected to PFGE using 1% agarose gels (Pulsed Field Certified Agarose; Bio-Rad) in 0.5× Tris-borate-EDTA buffer with a CHEF-DR III system (Bio-Rad). Gels were stained with 0.5 µg/mL ethidium bromide, visualized under UV light, and photographed using a GelDocTM XR System (Bio Rad). PFGE patterns were analyzed using Bionumerics version 6.1 (Applied Maths, Sint-Martens-Latem, Belgium) and clustered by UPGMA. A dendrogram was generated from a similarity matrix calculated using the Dice similarity coefficient with an optimization of 0.5% and a tolerance of 1%. PFGE clusters were defined as isolates with a similarity of 80% or higher on the dendrogram.1818 Tenover FC, Arbeit RD, Goering RV, et al. Interpreting chromosomal DNA restriction patterns produced by pulsed-field gel electrophoresis: criteria for bacterial strain typing. J Clin Microbiol. 1995;33:2233-9. SCCmec control strains were included [type I (NCTC10442); type II (N315); type III (85/2082); type IVa (CA05); type IVb (8/6-3P); type IVc (MR108); type IVd (JSC4469) and type V (WIS)], as well as iso- lates of the main circulating epidemic clones in Latin America (Brazilian Epidemic Clone, New York/Japan, USA300, USA400, Pediatric, OSPC, Cordobean, E-MRSA 15, E-MRSA 16).

Results

MRSA isolates were recovered mainly from lower respiratory tract samples (37.1%), followed by clinical osteomyelitis cases (19.4%), blood (13.7%), surgical wounds (9.7%), urine (4%), and abscesses (3.2%). In addition, 1.6% of MRSA were from surveillance cultures, and 11.3% were recovered from other anatomical sites. Considering the origin of the samples, 17 (13.7%) were considered community isolates and 107 (86.3%) hospital isolates.

MRSA presented the following resistance rates: amikacin (35.5%), gentamicin (33.1%), chloramphenicol (12.9%), tetracycline (20.2%), ciprofloxacin (79%), norfloxacin (72.6%), sulfamethoxazole-trimethoprim (20.2%), clindamycin (75%), and erythromycin (81.5%). Also, 93 strains (75%) showed production of β-lactamase. All isolates were susceptible to linezolid and tigecycline.

All isolates were susceptible to vancomycin and MICs are presented in Fig. 1. Seven isolates showed MIC of 3.0 µg/mL by Etest. By macrodilution three of them showed MIC of 1.0 µg/mL and four had MIC of 2.0 µg/mL. Etest also overestimated (above CLSI susceptibility breakpoint) teicoplanin MIC for one isolate but macrodilution defined its MIC as 4 µg/mL (susceptible by CLSI interpretative criteria).

Fig. 1
MIC of the glycopeptides to 124 MRSA determined by Etest. In (A), the values obtained for vancomycin. The seven isolates with MIC of 3.0 g/mL were considered susceptible because all MICs were ≤2.0 g/mL by microdilution. In (B), the results for teicoplanin. One isolate (MIC 12 g/mL) when tested by microdilution yielded an MIC of 4.0 g/mL (susceptible).

Daptomycin, an alternative to glycopeptides for the treatment of infections caused by MRSA, showed MCI values within the susceptibility range (Fig. 2), even though four isolates presented MIC of 1.0 µg/mL (upper limit of susceptibility category).

Fig. 2
MICs for daptomycin determined by Etest. All isolates were considered susceptible (MIC ≤ 1.0 g/mL). for all isolated S. aureus and these rates are even lower when

Although predominant SCCmec was type III (54%, 67/124), there was a heterogeneous distribution of SCCmec types: type II (21.8%), type IVa (10.5%), type IVc (3.2%) and type IVb (2.4%). Five isolates carried types I and II together. Among CA-MRSA (n = 17), only four showed SCCmec type IV: two IVa and two IVb. Among the other 13 isolates, eight had SCCmec type III and five had type II.

Of the 124 isolates, 23 (18.5%) had a positive D test: 20 (87%) had ermA gene and three (13%) carried ermC. Twelve (9.7%) isolates presented resistance to erythromycin and susceptibility to clindamycin (negative D test) and had no positive PCR reaction. Fifty-six (45.1%) isolates have had constitutive resistance mechanism and only 33 (26.6%) were susceptible to both antibiotics.

Twenty-six clones (Fig. 3) were observed, grouping 72 isolates (with five being the highest number of isolates per clone). Indeed, 52 isolates presented a unique pulsotype. Isolates belonging to all clones carried SCCmec type III (Table 1).

Fig. 3
Dendrogram illustrating the PFGE patterns of 124 strains and controls. Twenty-six clones were observed.

Table 1
Epidemiological and antibiotic susceptibility characteristics of the 26 clones.

Discussion

The prevalence of MRSA in the state of Santa Catarina is extremely low and is comparable to rates found in Scandinavian countries.2Otto M. MRSA virulence and spread. Cell Microbiol. 2012;14:1513-21. , 1919 Faria NA, Oliveira DC, Westh H, et al. Epidemiology of emerging methicillin-resistant Staphylococcus aureus (MRSA) in Denmark: a nationwidestudy in a country with low prevalence of MRSA infection. J Clin Microbiol. 2005;43:1836-42. , 2020 Elstrom P, Kacelnik O, Bruun T, Iversen B, Hauge SH, Aavitsland P. Meticillin-resistant Staphylococcus aureus in Norway, a low-incidence country, 2006-2010. J Hosp Infect. 2012;80:36-40. Isolation rates are in the range of 4-8% for all isolated S. aureusand these rates are even lower when only nosocomial isolates are considered (less than 2%). Such low occurrence of MRSA justifies the intriguing low number of MRSA included in this study, as the two most populous cities of Santa Catarina were included. In a report published by the World Health Organization (WHO), several European countries have national surveillance data with very low rates of MRSA: Denmark (1.2%), Estonia (1.7%), Finland (2.8%), Iceland (2.8%), Netherlands (1.4%), Norway (0.3%) and Sweden (0.8%).2121 World Health Organization. Antimicrobial resistance - global report on surveillance. World Health Organization; 2014. These countries may have succeeded in maintaining low MRSA rates because of effective search-and-destroy policies and/or controlled antibiotic overuse.2222 Otto M. Community-associated MRSA: what makes them special? Int J Med Microbiol. 2013;303:324-30. Of note, occurrence of MRSA in Santa Catarina differs greatly from other regions of Brazil, which have, in general, MRSA rates of around 29%.2323 Jones RN, Guzman-Blanco M, Gales AC, et al. Susceptibility rates in Latin American Nations: Report from a Regional Resistance Surveillance Program (2011). Braz J Infect Dis. 2013;17:672-81. , 2424 Toledo PV, Arend L, Pilonetto M, et al. Surveillance program for multidrug resistant bacteria in healthcare associated infections - a city perspective at South Brazil. J Hosp Infect. 2012;80:351-3. As far as we know, those search-and-destroy policies are not practiced in Santa Catarina and, surprisingly, MRSA isolation rates are similar to those found in the Scandinavian countries.

There was a predominance of isolates from lower respiratory tract infections, osteomyelitis, and bloodstream infections. These data are quite distinct from those found in studies with similar characteristics, which demonstrate a predominance of bloodstream infections (39%)2525 Kuo SC, Chiang MC, Lee WS, et al. Comparison of microbiological and clinical characteristics based on SCCmec typing in patients with community-onset meticillin-resistant Staphylococcus aureus (MRSA) bacteraemia. Int J Antimicrob Agents. 2011;39:22-6. or skin and soft tissue infections (61.5%).2626 Huang H, Flynn NM, King JH, Monchaud C, Morita M, Cohen SH. Comparisons of community-associated methicillin-resistant Staphylococcus aureus (MRSA) and hospital-associated MRSA infections in sacramento, California. J Clin Microbiol. 2006;44:2423-7.

Compared to the antimicrobial surveillance in the multicenter study SENTRY,1Gales AC, Sader HS, Ribeiro J, Zoccoli C, Barth A, Pignatari AC. Antimicrobial susceptibility of gram-positive bacteria isolated in Brazilian Hospitals Participatingin the SENTRY Program (2005-2008). Braz J Infect Dis. 2009;13:90-8.resistance rates in this study were much lower: ciprofloxacin (91.4-79%), tetracycline (46.7-20.2%), trimethoprim-sulfamethoxazole (68.1-20.2%), clindamycin (87.9-75%) and erythromycin (94-81.5%). A possible explanation for the large differences in rates of susceptibility could be due to the epidemiological profile.

Cavalcante et al. proposed phenotypic markers associated with SCCmec types. Resistance to tetracycline and trimethoprim-sulfamethoxazole may be associated with SCCmec type III, in which 100% resistance was found to both drugs. SCCmec type IV had absolute susceptibility, with only 2% of the isolates resistant to trimethoprim-sulfamethoxazole and 100% susceptibility to tetracycline.2727 Cavalcante FS, Schuenk FP, Caboclo RMF, Ferreira DC, Nouér SA, Santos KRN. Tetracycline and trimethoprim/sulfamethoxazole at clinical laboratory: can they help to characterize Staphylococcus aureus carrying different SCCmec types? Rev Soc Bras Med Trop. 2013;46:100-2.We found a predominance of SCCmec type III, which justifies why the resistance rates in our study were lower than those found in the rest of Brazil.

The presence of β-lactamase may result in unusual phenotypes known as BORSA (Borderline Oxacillin Resistant S. aureus). These bacteria, despite lacking the mecA gene, may be resistant to oxacillin and are phenotypically characterized as MRSA.2828 Maalej SM, Rhimi FM, Fines M, Mnif B, Leclercq R, Hammami A. Analysis of borderline oxacillin-resistant Staphylococcus aureus (BORSA) strains isolated in Tunisia. J Clin Microbiol. 2012;50:3345-8. They may also be responsible for elevated MICs of oxacillin. After therapy with β-lactams, these bacteria may induce the development of vancomycin resistance, a phenotype called β-lactam antibiotics-induced vancomycin resistant S. aureus (BIVR).2929 Hanaki H, Cui L, Dantsuji YI, et al.Antibiotic susceptibility survey of blood-borne MRSA isolates in Japan from 2008 through 2011. J Infect Chemother. 2014;20:527-34.

All MRSA were susceptible to vancomycin, teicoplanin and daptomycin. Although the phenotype of resistance to these drugs is uncommon.3030 Appelbaum PC. Microbiology of antibiotic resistance in Staphylococcus aureus. Clin Infect Dis. 2007;45:S165-70.31.45% of the isolates showed MIC of 2.0 µg/mL for vancomycin, which may suggest the development of a phenomenon of an upward trend for MICs for vancomycin, called "MIC creep".3131 Howden PH, Davies JK, Johnson PDR, Stinear TP, Grayson ML. Reduced vancomycinsusceptibility in Staphylococcus aureus, including vancomycin-intermediate and heterogeneous vancomycin-intermediate strains: resistance mechanisms, laboratory detection, and clinical implications. Clin Microbiol Rev. 2010;23:99-109.

The isolates demonstrated higher prevalence of gene ermA than ermC. The D test proved to be a methodology capable of detecting all isolates with inducible clindamycin resistance. Therefore, the test is easy to perform, inexpensive and is clinically relevant because it reduces the risk of inappropriate antibiotics use.3232 Fiebelkorn KR, Crawford SA, Mcelmeel ML, Jorgensen JH. Practical disk diffusion method for detectionofinducible clindamycin resistance in Staphylococcus aureus and coagulase-negative Staphylococci. J Clin Microbiol. 2003;41:4740-4.

In our study, there was a high prevalence of SCCmec type III (54%). In 2010, a study conducted at the Hospital de Clinicas de Porto Alegre (capital of the neighboring state of Rio Grande do Sul), a high prevalence of SCCmec type III was detected (49%),3333 Reiter KC, Machado ABMP, Freitas ALP, Barth AL.High prevalence of methicillin-resistant Staphylococcus aureus with SCCmec type III in cystic fibrosis patients in southern, Brazil. Rev Soc Bras Med Trop. 2010;43:377-81. similar to our findings. In 2005, in contrast to the local epidemiology, a study conducted at the Hospital de Clinicas de São Paulo found that 65% of MRSA carried SCCmec type IV.3434 Trindade PA, Pacheco RL, Costa SF, et al. Prevalence of SCCmec Type IV in nosocomial bloodstream isolates of methicillin-resistant Staphylococcus aureus. J Clin Microbiol. 2005;43:3435-7.

Not surprising, our isolates did not present a clonal dissemination, as both cities (Florianopolis and Blumenau) are separated by approximately 120 km and the isolates were collected during a period of three years.

Interestingly, we did not find clonal relationship between our isolates and the major circulating epidemic clones in Brazil, which may suggest that the state of Santa Catarina has different epidemiological characteristics compared to other regions in the country. Surveillance studies must be continuously conducted to better understand epidemiological dynamics of such a clinically relevant microorganism.

Conclusions

Although we identified the SCCmec that were present and eval- uated the presence of clones, the present study did not provide consistent scientific evidence for the low prevalence of MRSA in Santa Catarina, which was very different from the data found in other Brazilian states and some European countries.

We conclude that the MRSA epidemiological profile in Santa Catarina is similar to that found in the rest of Brazil, with a predominance of SCCmec type III, but the resistance rates were lower than those found in the rest of Brazil.

A wide variety of complexes with clonal isolates were detected without evidence of clonal spread, and a small amount of high genetic diversity was found.

Acknowledgements

The authors thank Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Conselho Nacional de Pesquisa e Desenvolvimento Tecnológico (CNPq) and Fundação de Amparo à Pesquisa do Rio Grande do Sul (FAPERGS) for financial support. Thanks to Laboratório Santa Luzia (Cassia Zoccoli and Nina Tobouti) and Laboratório Santa Isabel (Reginaldo Simões and Marcelo Molinari) for granting clinical samples.

REFERENCES

  • 1
    Gales AC, Sader HS, Ribeiro J, Zoccoli C, Barth A, Pignatari AC. Antimicrobial susceptibility of gram-positive bacteria isolated in Brazilian Hospitals Participatingin the SENTRY Program (2005-2008). Braz J Infect Dis. 2009;13:90-8.
  • 2
    Otto M. MRSA virulence and spread. Cell Microbiol. 2012;14:1513-21.
  • 3
    Koyama N, Inokoshi J, Tomoda H. Anti-infectious agents against MRSA. Molecules. 2013;18:204-24.
  • 4
    Herold BC, Immergluck LC, Maranan MC, et al. Community-acquired methicillin resistant Staphylococcus aureus in children with no identified predisposing risk. JAMA. 1998;279:593-8.
  • 5
    Figueiredo AMS, Ferreira FA. The multifaceted resources and microevolution of the successful human and animal pathogen methicillin-resistant Staphylococcus aureus. Mem Inst Oswaldo Cruz. 2014;109:1-14.
  • 6
    Shore AC, Coleman DC. Staphylococcal cassette chromossome mec: recents advances and new insights. Int J Med Microbiol. 2013;303:350-9.
  • 7
    Yamaki J, Lee M, Shriner KA, Wong-Beringer A. Can clinical and molecular epidemiologic parameters guide empiric treatment with vancomyc informe thicillin-resistant Staphylococcus aureus infections? Diagn Microbiol Infect Dis. 2011;70:124-30.
  • 8
    Jorgensen JH, Pfaller MA, Carroll KC, et al. Manual of clinical microbiology. 11th ed. Washington: ASMPress; 2015.
  • 9
    Clinical and Laboratory Standards Institute (CLSI). Performance standards for antimicrobial susceptibility testing. Seventeenth Informational Supplement, CLSI document M100-S23. Wayne, PA: Clinical Laboratory and Standards Institute; 2013.
  • 10
    European Committee on Antimicrobial Susceptibility Testing (EUCAST). Breakpoint tables for interpretation of MICs and zone diameters. Version 3.0; 2013.
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    Vannuffel P, Gigi J, Ezzedine H, et al. Specific detection of methicilin resistant Staphylococcus species by multiplex PCR. J Clin Microbiol. 1998;33:2864-7.
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    Zhang K, McClure JA, Elsayed S, Louie T, Conly JM. Novel multiplex PCR assay for characterization and concomitant subtyping of staphylococcal cassette chromosome mec types I to V in methicillin-resistant Staphylococcus aureus. J Clin Microbiol. 2003;43:5026-33.
  • 13
    Oliveira DC, Lencastre H. Multiplex PCR strategy for rapid identification of structural types and variants of the mec element in methicillin-resistant Staphylococcus aureus. Antimicrob Agents Chemother. 2002;46:2155-61.
  • 14
    Khan SA, Nawaz MS,Khan AA, Cerniglia CE. Simultaneous detection of erythromycin-resistant methylase genes ermA and ermC from Staphylococcus spp. By multiplex-PCR. Mol Cell Probes. 1999;13:381-7.
  • 15
    Lina G, Quaglia A, Reverdy ME, Leclercq R, Vandenesch F, Etienne J. Distribution of genes encoding resistance to macrolides, lincosamides, and streptogramins among Staphylococci. Antimicrob Agents Chemother. 1999;43:1062-6.
  • 16
    McDougal LK, Steward CD, Killgore GE, Chaitram JM, McCallister SK, Tenover FC. Pulsed-field gel electrophoresis typing of oxacillin-resistant Staphylococcus aureus isolates from the United States: establishing a national database. J Clin Microbiol. 2003;41:5113-20.
  • 17
    Pinto TCA, Souza ARV, D Pina SECM, et al. Optochin-Resistant Streptococcus pneumoniae: Phenotypic and Molecular Characterization of Isolates from Brazil with Description of Five Novel Mutations in the atpC Gene. J Clin Microbiol. 2013;51:3242-9.
  • 18
    Tenover FC, Arbeit RD, Goering RV, et al. Interpreting chromosomal DNA restriction patterns produced by pulsed-field gel electrophoresis: criteria for bacterial strain typing. J Clin Microbiol. 1995;33:2233-9.
  • 19
    Faria NA, Oliveira DC, Westh H, et al. Epidemiology of emerging methicillin-resistant Staphylococcus aureus (MRSA) in Denmark: a nationwidestudy in a country with low prevalence of MRSA infection. J Clin Microbiol. 2005;43:1836-42.
  • 20
    Elstrom P, Kacelnik O, Bruun T, Iversen B, Hauge SH, Aavitsland P. Meticillin-resistant Staphylococcus aureus in Norway, a low-incidence country, 2006-2010. J Hosp Infect. 2012;80:36-40.
  • 21
    World Health Organization. Antimicrobial resistance - global report on surveillance. World Health Organization; 2014.
  • 22
    Otto M. Community-associated MRSA: what makes them special? Int J Med Microbiol. 2013;303:324-30.
  • 23
    Jones RN, Guzman-Blanco M, Gales AC, et al. Susceptibility rates in Latin American Nations: Report from a Regional Resistance Surveillance Program (2011). Braz J Infect Dis. 2013;17:672-81.
  • 24
    Toledo PV, Arend L, Pilonetto M, et al. Surveillance program for multidrug resistant bacteria in healthcare associated infections - a city perspective at South Brazil. J Hosp Infect. 2012;80:351-3.
  • 25
    Kuo SC, Chiang MC, Lee WS, et al. Comparison of microbiological and clinical characteristics based on SCCmec typing in patients with community-onset meticillin-resistant Staphylococcus aureus (MRSA) bacteraemia. Int J Antimicrob Agents. 2011;39:22-6.
  • 26
    Huang H, Flynn NM, King JH, Monchaud C, Morita M, Cohen SH. Comparisons of community-associated methicillin-resistant Staphylococcus aureus (MRSA) and hospital-associated MRSA infections in sacramento, California. J Clin Microbiol. 2006;44:2423-7.
  • 27
    Cavalcante FS, Schuenk FP, Caboclo RMF, Ferreira DC, Nouér SA, Santos KRN. Tetracycline and trimethoprim/sulfamethoxazole at clinical laboratory: can they help to characterize Staphylococcus aureus carrying different SCCmec types? Rev Soc Bras Med Trop. 2013;46:100-2.
  • 28
    Maalej SM, Rhimi FM, Fines M, Mnif B, Leclercq R, Hammami A. Analysis of borderline oxacillin-resistant Staphylococcus aureus (BORSA) strains isolated in Tunisia. J Clin Microbiol. 2012;50:3345-8.
  • 29
    Hanaki H, Cui L, Dantsuji YI, et al.Antibiotic susceptibility survey of blood-borne MRSA isolates in Japan from 2008 through 2011. J Infect Chemother. 2014;20:527-34.
  • 30
    Appelbaum PC. Microbiology of antibiotic resistance in Staphylococcus aureus. Clin Infect Dis. 2007;45:S165-70.
  • 31
    Howden PH, Davies JK, Johnson PDR, Stinear TP, Grayson ML. Reduced vancomycinsusceptibility in Staphylococcus aureus, including vancomycin-intermediate and heterogeneous vancomycin-intermediate strains: resistance mechanisms, laboratory detection, and clinical implications. Clin Microbiol Rev. 2010;23:99-109.
  • 32
    Fiebelkorn KR, Crawford SA, Mcelmeel ML, Jorgensen JH. Practical disk diffusion method for detectionofinducible clindamycin resistance in Staphylococcus aureus and coagulase-negative Staphylococci. J Clin Microbiol. 2003;41:4740-4.
  • 33
    Reiter KC, Machado ABMP, Freitas ALP, Barth AL.High prevalence of methicillin-resistant Staphylococcus aureus with SCCmec type III in cystic fibrosis patients in southern, Brazil. Rev Soc Bras Med Trop. 2010;43:377-81.
  • 34
    Trindade PA, Pacheco RL, Costa SF, et al. Prevalence of SCCmec Type IV in nosocomial bloodstream isolates of methicillin-resistant Staphylococcus aureus. J Clin Microbiol. 2005;43:3435-7.

Publication Dates

  • Publication in this collection
    Jul-Aug 2015

History

  • Received
    30 Oct 2014
  • Accepted
    22 Apr 2015
Brazilian Society of Infectious Diseases Rua Augusto Viana, SN, 6º., 40110-060 Salvador - Bahia - Brazil, Telefax: (55 71) 3283-8172, Fax: (55 71) 3247-2756 - Salvador - BA - Brazil
E-mail: bjid@bjid.org.br