Comparison of polymerase chain reaction and conventional methods in detecting methicillin-resistant Staphylococcus aureus

Adaleti, Rıza; Nakipoğlu, Yaşar; Karahan, Zeynep Ceren; Tasdemir, Cihan; Kaya, Fatma Nur

doi:10.3855/jidc.321

Cited by 7 publications

(3 citation statements)

References 18 publications

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“…The oxacillin agar screen method has also been recommended for confirmation of suspected strains by the CLSI. The studies evaluating these tests have showed that they have acceptable performance; in general, sensitivity (94.1%-100%) and specificity (87.4%-100%) ranges of the oxacillin disk diffusion method, cefoxitin disk diffusion method, and oxacillin agar screen test in these studies were found to be similar to those found in our study [19][20][21]. In Baddour et al's study [22], the oxacillin agar screen and PBP2a latex agglutination methods were reported to be more sensitive than the oxacillin and cefoxitin disk diffusion methods, and cefoxitin disk diffusion was found to be the most specific method.…”

Section: Discussionsupporting

confidence: 86%

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Methicillin-resistant S. aureus colonization in intensive care unit patients: Early identification and molecular typing

Durmaz

Sanci

et al. 2016

J Infect Dev Ctries

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Introduction: Early detection of methicillin-resistant Staphylococcus aureus (MRSA) in colonized patients is very important for infection control procedures to prevent MRSA spread. We aimed to monitor MRSA carriage in intensive care unit (ICU) patients and to evaluate the speed and efficiency of conventional culture, immunological, chromogenic, and molecular methods together with genotyping. Methodology: Nasal and axillar swab specimens were obtained from patients in the ICUs of the general surgery and neurosurgery wards in a tertiary hospital once a week over four weeks between December 2009 and July 2010. Oxacillin and cefoxitin disk diffusion tests, oxacillin agar screening test, latex agglutination test, chromogenic agar, and real-time polymerase chain reaction (PCR) tests were used for isolation and identification of MRSA. MRSA isolates were typed using ribotyping and pulsed-field gel electrophoresis (PFGE) typing. Results: MRSA colonization was detected in 48 of 306 patients by real-time PCR. The MRSA colonization rate was 6.2%, 15.5%, and 38.5% at admission and in the first and second weeks, respectively. Sensitivity, specificity, positive and negative predictive values for all phenotypic tests were 98%, 99.6%, 98%, and 99.6%, respectively. The shortest handle time was observed in PCR. A total of three banding patterns were obtained from MRSA isolates by ribotyping, and PFGE analyses revealed 17 different pulsotypes varying from 11 to 18 distinct bands, showing high genetic diversity among the samples. Conclusion: Phenotypic MRSA screening tests in our study exhibited similar performances. The superiority of real-time PCR is its short turnaround time.

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Section: Discussionsupporting

confidence: 86%

“…[19][20][21]24]. Compared with the chromogenic agar MRSA assay, PCR had sensitivity, specificity, and positive and negative predictive values of 100%, 98.6%, 95.8%, and 100%, respectively, and the mean PCR turnaround time was 14.5 hours [4].…”

Section: Discussionmentioning

confidence: 99%

Methicillin-resistant S. aureus colonization in intensive care unit patients: Early identification and molecular typing

Durmaz

Sanci

et al. 2016

J Infect Dev Ctries

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“…The antibiotic susceptibility test revealed that 50 strains were resisted to oxacillin/cefoxitin. Further, methicillin resistance in staphylococci isolated from clinical samples by Rahbar was 53% in Tehran and 51% of MRSA were also reported in Turkey (26).…”

Section: Discussionmentioning

confidence: 90%

Molecular Typing of ccrB Gene in Methicillin-resistant Staphylococcus aureus by Restriction Fragment Length Polymorphism

Noorbakhsh¹,

Atayifar²,

Karizi³

2019

Avicenna J Clin Microbiol Infect

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Staphylococcus aureus is considered as one of the most essential bacterial pathogens in humans that can cause various infections in patients ranging from skin infections to fatal necrotizing pneumonia, bacteremia, and endocarditis (1). Methicillin-resistant S. aureus (MRSA) is one of the important pathogens that is responsible for many nosocomial infections. First, MRSA was identified only in the hospitals, but 30 years later, the first virulent MRSA was acquired from the community (2). The resistance to methicillin in S. aureus is induced by the presence of the mecA gene, encoding low-affinity penicillin-binding protein PBP2a (78 KD) (3,4). MRSA has a mobile genetic element staphylococcal cassette chromosome mec (SCCmec) carrying the mecA gene. (5-7) SCCmec elements in S. aureus are as unique genomic islands with 2 essential components (i.e., the ccr and the mec gene complexes) and J region (5,8,9). The ccr gene complex is composed of ccr genes encoding 2 sitespecific recombinases (ccrA and ccrB), and the mecA gene complex contains mecA and regulatory genes mecI and mecR. (6,10,11) Zhang et al defined 8 different types of SCCmec in the combination of ccr and mec complex. While types I-V were widespread (12), other types existed in the strains of the country from which they were originated (13,14). SCCmec exchange between species is related to the ccr gene expression (15). Several allotypes of ccr and mec gene are classified in SCCmec. The 5 allotypes of the ccr gene complex include ccrAB1, ccrAB2, ccrAB3, ccrAB4, and ccrC (16,17), and 5 classes of the mec gene complex (types I-V) were described and SCCmec type IV has 8 individual subtypes (18,19).The site-specific recombination of SCCmec is catalyzed by its encoded ccr recombinases, ccrA and ccrB for types I to IV and ccrC for type V. In addition, ccrA and ccrB belong to a family of large serine invertase and resolvases

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Optimized In Vitro Antibiotic Susceptibility Testing Method for Small-Colony Variant Staphylococcus aureus

Precit

Wolter

Griffith

et al. 2016

Antimicrob Agents Chemother

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bStaphylococcus aureus small-colony variants (SCVs) emerge frequently during chronic infections and are often associated with worse disease outcomes. There are no standardized methods for SCV antibiotic susceptibility testing (AST) due to poor growth and reversion to normal-colony (NC) phenotypes on standard media. We sought to identify reproducible methods for AST of S. aureus SCVs and to determine whether SCV susceptibilities can be predicted on the basis of treatment history, SCV biochemical type (auxotrophy), or the susceptibilities of isogenic NC coisolates. We tested the growth and stability of SCV isolates on 11 agar media, selecting for AST 2 media that yielded optimal SCV growth and the lowest rates of reversion to NC phenotypes. We then performed disk diffusion AST on 86 S. aureus SCVs and 28 isogenic NCs and Etest for a subset of 26 SCVs and 24 isogenic NCs. Growth and reversion were optimal on brain heart infusion agar and Mueller-Hinton agar supplemented with compounds for which most clinical SCVs are auxotrophic: hemin, menadione, and thymidine. SCVs were typically nonsusceptible to either trimethoprim-sulfamethoxazole or aminoglycosides, in accordance with the auxotrophy type. In contrast, SCVs were variably nonsusceptible to fluoroquinolones, macrolides, lincosamides, fusidic acid, and rifampin; mecA-positive SCVs were invariably resistant to cefoxitin. All isolates (both SCVs and NCs) were susceptible to quinupristin-dalfopristin, vancomycin, minocycline, linezolid, chloramphenicol, and tigecycline. Analysis of SCV auxotrophy type, isogenic NC antibiograms, and antibiotic treatment history had limited utility in predicting SCV susceptibilities. With clinical correlation, this AST method and these results may prove useful in directing treatment for SCV infections. Staphylococcus aureus causes diverse infections ranging in severity from benign to life-threatening. Persistent and relapsing S. aureus infections often occur despite prolonged antimicrobial therapy and have been linked to the emergence of small-colony variants (SCVs). S. aureus SCVs have been associated with a poor response to antibiotic treatment (1, 2) and are often recovered from many chronic infections, including endocarditis (3, 4), osteomyelitis (5), device infections (3), soft tissue infections (6), and airway infections (7,8). SCV airway infections are particularly prevalent among people with the genetic disease cystic fibrosis (CF), affecting between 8 and 33% of CF patients, often following prolonged antibiotic treatment (1, 7). In children with CF, SCV respiratory infection was found to be independently associated with worse lung function and faster lung function decline (9).SCVs are typically identified by distinctive phenotypic traits when grown on most agar-based media. SCVs produce colonies approximately 1/10 the size of normal-colony (NC) S. aureus isolates (Fig. 1), and they are characteristically nonhemolytic and nonpigmented and have diminished coagulase production (10). SCVs usually carry mutations in one of a few, ...

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Comparison of polymerase chain reaction and conventional methods in detecting methicillin-resistant Staphylococcus aureus

Cited by 7 publications

References 18 publications

Methicillin-resistant S. aureus colonization in intensive care unit patients: Early identification and molecular typing

Methicillin-resistant S. aureus colonization in intensive care unit patients: Early identification and molecular typing

Molecular Typing of ccrB Gene in Methicillin-resistant Staphylococcus aureus by Restriction Fragment Length Polymorphism

Optimized In Vitro Antibiotic Susceptibility Testing Method for Small-Colony Variant Staphylococcus aureus

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