scholarly journals The Phenotypic and Genetic Detection of the Methicillin-Resistant Staphylococcus aureus (MRSA)

2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Eftychios V ◽  
Laura VM ◽  
Calina-Oana Z ◽  
Evangelos V ◽  
Marina P ◽  
...  
Keyword(s):  
Meca Gene ◽  
Latex Agglutination ◽  
Agglutination Test ◽  
Latex Agglutination Test ◽  
Disk Diffusion ◽  
Methicillin Resistant ◽  
Pcr Method ◽  
Resistant Strains ◽  
Mrsa Strains ◽  
Cefoxitin Disk

Methicillin resistant strains of Staphylococcus aureus (MRSA) were identified shortly upon the introduction of methicillin into the clinical practice. The S. aureus samples were taken from patients hospitalized in General Hospital of Chania “Agios Georgios”. The strains were isolated from different pathological products, in the hospital laboratory. All isolates were tested using the cefoxitin disk diffusion, the oxacillin MIC methods and the PBP2’ latex agglutination test (bioMérieux), for the production of the Penicillin-Binding Protein 2a (PBP2a or PBP2’ protein). S. aureus ATCC 29213 was used as a negative control. We followed the detection of the mecA gene throughout the PCR method, as the standard “gold” method, in order to identify MRSA strains. Conventional methods for MRSA strains detection were compared with the PCR method. The antibiotic susceptibility testing was performed throughout the Kirby-Bauer disk diffusion method using antibiotic discs from Bioanalyse ltd. The mecA gene was found by PCR in 57.5 % of S. aureus strains, which allowed defining the isolated strains as MRSA strains. According to the oxacillin MIC values of the studied strains, 25 strains (53.2%) were identified as MRSA, 21 (44.68%) as MSSA and 1*strain (2.13%) as Borderline (BL) MRSA. The mecA gene is present in 24 of the MRSA strains with oxacillin MIC ≥ 4 being more common in strains showing the oxacillin MICs ≥ 256 (12/27). Adding the BL strains to the methicillin resistant strains, the rate of the MRSA strains increases to 26 (55.32%), the appropriate values of the MRSA strains percent, as determined by the PCR method (57.45%), which shows a concordance of 96.3% (26/27), between the results obtained by the two tests. Comparing the results obtained using the PCR method; with the oxacillin MICs and the PBP2’ latex agglutination test, concordant results were obtained for 89.36% of the strains (42/47) by oxacillin MICs and for 97.87% of the strains (46/47) by PBP2’ latex agglutination test. We conclude that the specificity of these methods is 100% for the mecA PCR method, 97.87% for the PBP2a latex method and 89.36% for the oxacillin MIC. The comparison of phenotypic methods (the PBP2a latex reaction, oxacillin MICs, the Cefoxitin disk diffusion test with the genotypic methods (the presence of the mecA gene), reveals that the PBP2a latex reaction has high sensitivity (97.87%), and can be used as an alternative method to PCR for the MRSA detection, in resource constraint settings.

scholarly journals Detection of mecA gene by latex agglutination and its molecular analysis by PCR in methicillin resistant staphylococcus aureus.

2020 ◽  
Vol 27 (07) ◽  
pp. 1363-1370
Author(s):  
Aneela Khawaja ◽  
Iffat Javed ◽  
Sohaila Mushtaq ◽  
Saeed Anwar ◽  
Faiqa Arshad ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
Latex Agglutination ◽  
Medical Institute ◽  
Cross Sectional ◽  
Methicillin Resistant ◽  
Agglutination Method ◽  
Resistant Strains

Antimicrobial resistance (AMR) is a devastating question that is threatening the health globally. The extensive and indiscriminative use of antibiotics has evolved a notorious resistance in Staphylococcus aureus.  This resistance developed through possession of mecA gene, which codes for modified penicillin binding protein (PBP2a) and the emergent strain being labeled “methicillin resistant Staphylococcus aureus”. Conventional phenotypic techniques for detection of MRSA rely on standardization of cultural characteristics. The drawbacks of diagnostic error to report MRSA include: poor prognosis, expensive treatment, dissemination of multi-drug resistant strains and even treatment failure. Latex agglutination method can be adopted as a more accurate and quick strategy for rapid detection of methicillin resistance. Objectives: To compare detection of mecA gene in methicillin resistant isolates of Staphylococcus aureus by latex agglutination and PCR; by assessing the sensitivity and specificity of both methods. Study Design: Descriptive Cross-Sectional study. Setting: Pathology Department, Post Graduate Medical Institute, Lahore. Period: From January 2015 to December 2015; according to standard operating procedures at Microbiology laboratory. Material & Methods: A total 713 consecutive, non-duplicate isolates of Staphylococcus aureus were processed. Methicillin resistance was determined using cefoxitin (30mg) by Kirby-Bauer method using CLSI guideline (2016), latex agglutination method; and PCR for mecA gene. Results: The results showed that out of 713 Staphylococcus aureus isolates, 92 (12.90%) isolates were resistant to cefoxitin and were labelled as MRSA. majority MRSA isolates recovered from pus (44.57%) and wound swab (20.65%), followed by blood (13.04%), fluid (8.70%), CSF (4.35%), CVP (3.26%), HVS (3.26%) and tracheal secretion (2.17%). By latex agglutination method, 87 (94.50%) were positive for PBP2a; while on PCR mecA gene was detected only in 82 (89.10%) MRSA isolates. When assessed with PCR (gold standard) the sensitivity and diagnostic accuracy of latex agglutination was 100% and 94.57%, respectively. Conclusion: Latex agglutination test can be employed as rapid and reliable diagnostic technique in MRSA isolates for mecA gene detection, where resources for molecular methods are inadequate. This can effectually lessen the misdiagnosis of resistant strains, and over/ ill-use of antibiotics.

scholarly journals Ceftaroline resistance in Staphylococcus pseudintermedius gene mecA carriers

2018 ◽  
Vol 38 (12) ◽  
pp. 2233-2236
Author(s):  
Carolina B. Scherer ◽  
Larissa S. Botoni ◽  
Antônio U. Carvalho ◽  
Kelly M. Keller ◽  
Adriane P. Costa-Val
Keyword(s):  
Methicillin Resistance ◽  
Meca Gene ◽  
Disk Diffusion ◽  
Diffusion Test ◽  
Staphylococcus Pseudintermedius ◽  
Ceftaroline Fosamil ◽  
Disk Diffusion Test ◽  
Methicillin Resistant ◽  
Resistant Strains ◽  
Current Report

ABSTRACT: Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) being a constant concern, ceftaroline fosamil has been recently approved as a new cephalosporin, active against MRSA, for use in humans; only rare cases of resistance have been reported till date. There is no report of resistance to ceftaroline in Staphylococcus pseudintermedius, which is the main bacterium causing dermatitis and otitis in dogs. To evaluate staphylococcal resistance to ceftaroline, 35 isolates of methicillin-resistant S. pseudintermedius (MRSP), carrying the mecA gene, from 26 dogs with folliculitis and nine dogs with external otitis, underwent disk diffusion test with cefoxitin, oxacillin, and ceftaroline. Tests with cefoxitin and oxacillin showed > 90% sensitivity in methicillin resistance detection. In the disk diffusion test, 97.14% (34/35) were resistant to cefoxitin, 94.29% (33/35) to oxacillin, and 31.43% (11/35) to ceftaroline. Of the ceftaroline-resistant strains, 27.27% (3/11) were obtained from the ears of dogs while the rest (8/11) were from the skin. The current report is the first description of MRSP resistance to ceftaroline.

scholarly journals Comparison of rapid and conventional methods for investigating of mecA presence in Staphylococcus Species

2021 ◽  
Vol 37 (5) ◽  
Author(s):  
Selim Görgün ◽  
Hacer İşler ◽  
Mehmet Cenk Turgut
Keyword(s):  
Methicillin Resistance ◽  
Meca Gene ◽  
Latex Agglutination ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Chain Reaction ◽  
Disk Diffusion Method ◽  
Chromogenic Agar ◽  
Pcr Method ◽  
Conventional Methods

Objectives: Taking the determination of mecA gene by polymerized chain reaction (PCR) method as a reference in determining methicillin resistance in Staphylococcus species, we aimed at comparing the reliability levels of disk diffusion, latex agglutination test and chromogenic agar use methods. Methods: This prospective study was conducted on 228 Staphylococcus strains isolated between January 2020 and December 2020 in Samsun Training and Research Hospital. Disk diffusion, latex agglutination and chromogen agar medium methods were applied along with the polymerized chain reaction (PCR) method. Results: The mecA gene was detected in 47 of the isolates (20.6%) by the PCR method, and these isolates were accepted as methicillin-resistant. When the PCR result was taken as a reference, the sensitivity of the disk diffusion method became 100%, and specificity became 45.9%; sensitivity of latex agglutination was determined as 80.9%, and specificity as 70.2%; sensitivity of chromogenic agar as 85.1% and its specificity was found to be 95%. Only in S. aureus isolates, the highest sensitivity and specificity rate (100% and 88%, respectively) belonged to chromogenic agar. Conclusion: Chromogenic agar provides more reliable data for S. aureus isolates, and the combined use of all three methods does not significantly increase reliability. doi: https://doi.org/10.12669/pjms.37.5.4274 How to cite this:Gorgun S, Isler H, Turgut MC. Comparison of rapid and conventional methods for investigating of mecA presence in Staphylococcus Species. Pak J Med Sci. 2021;37(5):---------. doi: https://doi.org/10.12669/pjms.37.5.4274 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

scholarly journals Research on the Phenotypic Characterization of Mrsa Strains Isolated from Animals

2017 ◽  
Vol 74 (1) ◽  
pp. 88
Author(s):  
Iulia Maria BUCUR ◽  
Viorel HERMAN ◽  
Corina PASCU ◽  
Ionita IANCU ◽  
Janos DEGI ◽  
...  
Keyword(s):  
Methicillin Resistance ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Phenotypic Characterization ◽  
Diffusion Test ◽  
Chromogenic Medium ◽  
Disk Diffusion Test ◽  
Methicillin Resistant ◽  
Resistant Strains ◽  
Mrsa Strains

Keywords: chromogen, methicillin, MRSA, resistanceIntroduction: Currently, both in staphylococci isolated from animals with different diseases, as well as in humans, the MRSA strains (Methicillin Resistant S. aureus) are monitored, as the methicillin resistance is associated with the resistance to other antibiotic groups.Methicillin resistance is encoded by mec staphylococcal chromosomal cassettes (SCCmec), which are islands of resistance. These strains can be identified by molecular biology tests and tests that reveal several phenotypic characteristics.The research was made in order to characterize and identify phenotypically the MRSA staphylococci strains isolated from animals.Materials and Methods: Researches were made on 240 coagulase positive and coagulase negative strains of staphylococci. Mannitol fermentation was tested on Champan medium, free coagulase was revealed on Baird-Parker medium and to identify S. aureus subsp. aureus was used the chromogenic medium Chromatic Staph.Methicillin-resistant strains were detected by disc diffusion method, using biodiscs with methicillin, oxacillin and cefoxitin. Also, to identify the MRSA strains, was used the chromogenic medium Chromatic MRSA.Results: The isolates were positive to mannitol and produced complete haemolysis or were unhaemolytic. A total of 44 strains produced free coagulase on Baird-Parker medium, considered coagulase positive strains, while 196 were coagulase negative strains.The isolates conducted differently to methicillin: 22,08% of strains were resistant, 51,25% of strains were susceptible and 26,66% had intermediate resistance, while the resistant strains to oxacillin were 42,91%.The increased frequency of methicillin-resistant strains of staphylococci and, particularly, MRSA strains, determined using the cefoxitin disk diffusion test, which is more reliable than methicillin and oxacillin.On the MRSA chromogenic medium, the methicillin-resistant strains of staphylococci formed colonies with pigment from mauve to orange mauve.Conclusion: The obtained results by disk diffusion test on resistance patterns to 3 beta-lactams, resistant to penicillinase, indicated a different frequency of the resistant strains to these antibiotics.Cefoxitin disk diffusion test revealed a frequency of 2,51% of resistant strains, that can be considered MRSA strains.

scholarly journals Marked Presence of Methicillin-Resistant Staphylococcus aureus in Wild Lagomorphs in Valencia, Spain

Animals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1109
Author(s):  
Elena Moreno-Grúa ◽  
Sara Pérez-Fuentes ◽  
David Viana ◽  
Jesús Cardells ◽  
Víctor Lizana ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Meca Gene ◽  
High Density ◽  
Anatomical Location ◽  
Methicillin Resistant ◽  
Mlst Type ◽  
Resistance To Penicillin ◽  
Resistant Strains ◽  
Wild Lagomorphs ◽  
Mrsa Strains

The appearance of methicillin-resistant strains of Staphylococcus aureus (MRSA) in several animal species (including rabbits) has set off alarms for their capacity to act as reservoirs for this bacterium. This is especially important in wild animals given its epidemiological implications. The objectives of this study were to identify and characterize S. aureus, specifically MRSA, strains in wild lagomorph high-density areas. Ten hares and 353 wild rabbits from 14 towns with a high rabbit density in the Valencian region (eastern Spanish coast) were sampled. Swabs from the nasal cavity, ears, perineum and lesions (when present) were taken for microbiological studies. The detection of different genes and antibiotic susceptibility studies were also carried out. Of all the animals, 41.3% were positive for S. aureus, of which 63.3% were MRSA. Ears were the anatomical location with more S. aureus and MRSA strains. The more frequently identified MLST type was ST1945 (97.1%, 136/140). The mecA gene was found only in one sample. The rest (n = 139) carried the mecC gene and were included in CC130, except one. Penicillin resistance was detected in 28 mec-negative isolates and, in one case, bacitracin resistance. mecA isolate presented resistance to enrofloxacin and tetracycline, and 10 mecC isolates also showed bacitracin resistance. No MRSA isolate was positive for genes chp, sea, tst and PVL. Two ST1945 isolates contained IEC type E (comprising genes scn and sak). mecA-isolate was positive for blaZ. Of the 28 MSSA strains showing resistance to penicillin, 22 carried the blaZ gene. These surprising results highlight the marked presence of MRSA strains in wild rabbits in high-density areas.

scholarly journals Evaluation of Clinical Laboratory Standards Institute Interpretive Criteria for Methicillin-Resistant Staphylococcus Pseudintermedius Isolated from Dogs

2009 ◽  
Vol 21 (5) ◽  
pp. 684-688 ◽  
Author(s):  
Jennifer R. Schissler ◽  
Andrew Hillier ◽  
Joshua B. Daniels ◽  
Lynette K. Cole ◽  
Wondwossen A. Gebreyes
Keyword(s):  
Methicillin Resistance ◽  
False Negative ◽  
Meca Gene ◽  
Diagnostic Sensitivity ◽  
Disk Diffusion ◽  
Staphylococcus Pseudintermedius ◽  
Methicillin Resistant ◽  
Interpretive Criterion ◽  
Cefoxitin Disk ◽  
Cefoxitin Disk Diffusion

The Clinical and Laboratory Standards Institute published in 2008 new interpretive criteria for the identification of methicillin resistance in staphylococci isolated from animals. The sensitivity of the 2008 interpretive criteria for mecA gene-positive Staphylococcus pseudintermedius, compared with the previous criteria of 2004, was investigated. Thirty clinical isolates of methicillin-resistant S. pseudintermedius from dogs were used. The presence of the mecA gene was determined by polymerase chain reaction. The minimum inhibitory concentration for oxacillin was determined by broth microdilution. The 2008 breakpoint of 4 μg/ml for methicillin resistance resulted in a diagnostic sensitivity of 73.3% (22/30). The 2004 breakpoint guideline of 0.5 μg/ml resulted in a diagnostic sensitivity of 97% (29/30). For oxacillin disk diffusion, the 2008 interpretive criterion of 10 mm for methicillin resistance resulted in a sensitivity of 70% (21/30). If intermediate isolates (11 or 12 mm) were considered resistant, the sensitivity was 93% (28/30). Application of the 2004 interpretive criterion of 17 mm resulted in a diagnostic sensitivity of 100% (30/30). For cefoxitin disk diffusion, the interpretive criterion of 21 mm for methicillin resistance (as used for Staphylococcus aureus) resulted in a diagnostic sensitivity of 6.7% (2/30). The interpretive criterion of 24 mm (as used for coagulase-negative staphylococci) resulted in a diagnostic sensitivity of 43.3% (13/30). With the use of 2008 interpretive criteria, all 3 tests produced what we consider to be an unacceptable level of false negative results. Our findings also suggest that cefoxitin disk diffusion is an inappropriate screening test for methicillin resistance of canine S. pseudintermedius.

scholarly journals Sensitivity and Specificity of an Improved Rapid Latex Agglutination Test for Identification of Methicillin-Sensitive and -Resistant Staphylococcus aureus Isolates

1998 ◽  
Vol 36 (4) ◽  
pp. 1109-1112 ◽  
Author(s):  
Sandra C. Smole ◽  
Elyssa Aronson ◽  
Annette Durbin ◽  
Stephen M. Brecher ◽  
Robert D. Arbeit
Keyword(s):  
Staphylococcus Aureus ◽  
Sensitivity And Specificity ◽  
Second Generation ◽  
Latex Agglutination ◽  
Agglutination Test ◽  
Latex Agglutination Test ◽  
Clinical Isolates ◽  
Becton Dickinson ◽  
Methicillin Resistant ◽  
Previous Version

The performance of a second-generation rapid agglutination kit, Slidex Staph Plus (SSP; bioMérieux), was compared to those of the Slidex Staph (SS; bioMérieux), Staphaurex (SRX; Murex Diagnostics), and BBL Staphyloslide (BBL; Becton Dickinson) kits by using 508 clinical isolates composed of 150 methicillin-sensitiveStaphylococcus aureus (MSSA) organisms, 154 methicillin-resistant S. aureus (MRSA) organisms, and 204 non-S. aureus Staphylococcus spp. Of the 508 isolates tested, 75% were fresh clinical isolates, with the remainder taken from five different freezer collections. All four agglutination tests had comparable sensitivities for MSSA and MRSA. However, the SS kit was significantly less specific (93.1%) than the three other tests (P > 0.05, McNemar test). These results demonstrate that the new rapid latex agglutination kit, SSP, was more specific for the identification of S. aureus than the previous version and performed comparably to the SRX and BBL kits.

scholarly journals Rapid Slide Latex Agglutination Test for Detection of Methicillin Resistance in Staphylococcus aureus

1999 ◽  
Vol 37 (9) ◽  
pp. 2789-2792 ◽  
Author(s):  
Arjanne van Griethuysen ◽  
Miranda Pouw ◽  
Nan van Leeuwen ◽  
Max Heck ◽  
Piet Willemse ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Screen Test ◽  
Latex Agglutination ◽  
Agglutination Test ◽  
Latex Agglutination Test ◽  
Specific Test ◽  
Methicillin Resistant ◽  
Phage Types ◽  
Test Specificity

The MRSA screen test (Denka Seiken Co., Ltd.), a commercially available, rapid (20-min) slide latex agglutination test for the determination of methicillin resistance by detection of PBP 2a inStaphylococcus aureus, was compared with the oxacillin agar screen test and PCR detection of the mecA gene. A total of 563 S. aureus isolates were tested. Two hundred ninety-six of the isolates were methicillin-susceptible isolates from cultures of blood from consecutive patients. Also, 267 methicillin-resistant isolates that comprised 248 different phage types were tested. Methicillin resistance was defined as the presence of themecA gene. Of the 267 mecA gene-positive isolates, 263 were positive by the MRSA screen test (sensitivity, 98.5%), and all the mecA-gene negative strains were negative by the MRSA screen test (specificity, 100%). The oxacillin agar screen test detected methicillin resistance in 250 of themecA gene-positive isolates (sensitivity, 93.6%). The sensitivity of the MRSA screen test was statistically significantly higher than the sensitivity of the oxacillin agar screen test (P < 0.05). The MRSA screen test is a highly sensitive and specific test for the detection of methicillin resistance. Also, it offers results within half an hour and is easy to perform, which makes this test a valuable tool in the ongoing battle against methicillin-resistant S. aureus.

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