scholarly journals Detection of Methicillin Resistance in Staphylococcus Aureus by Polymerase Chain Reaction and Conventional Methods: A Comparative Study

2012 ◽  
Vol 4 (02) ◽  
pp. 083-088 ◽  
Author(s):  
Manju M Pillai ◽  
Ragunathan Latha ◽  
Gautam Sarkar
Keyword(s):  
Staphylococcus Aureus ◽  
Polymerase Chain Reaction ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
Disk Diffusion ◽  
Chain Reaction ◽  
Mannitol Salt Agar ◽  
Polymerase Chain ◽  
Conventional Methods ◽  
Phenotypic Methods

ABSTRACT Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen worldwide, which has emerged over the past 30 years as a leading cause of both nosocomial and community-acquired infections. Accurate and rapid identification of MRSA in clinical specimens is essential for timely decision on effective antimicrobial chemotherapy. Aim: The present study was conducted to compare two conventional phenotypic methods, oxacillin disk diffusion (ODD) Aim: The present study was conducted to compare two conventional phenotypic methods, oxacillin disk diffusion (ODD) method and mannitol salt agar (MSA) with oxacillin, with polymerase chain reaction (PCR) for mecA gene (as standard). Materials and Methods: A total of 165 consecutive clinical isolates of S. aureus received at the Department of Microbiology in our tertiary care teaching hospital were included in the study. All the isolates were subjected to ODD (1 μg) method, culture in MSA with oxacillin, and PCR for mecA gene. Results: The sensitivity and specificity of ODD test were found to be 93.5% (86.4-97.3%) and 83.5% (79.2-85.8%), respectively, and that of MSA with oxacillin were found to be 87.1% (79.5-92.3%) and 89.3% (84.8-92.5%), respectively. The time taken for diagnosing MRSA by conventional methods is 48-72 h, which is more as compared to PCR which takes 18-24 h. Conclusion: This study recommends advocating PCR for mecA gene on a regular basis for detecting methicillin resistance in S. aureus isolates isolated from sterile body fluids or from special units such as intensive care units.

scholarly journals Phenotypic and genotypic study on antibiotic resistance and pathogenic factors of Staphylococcus aureus isolates from small ruminant mastitis milk in South of Italy (Sicily)

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Alessio Parco ◽  
Giusi Macaluso ◽  
Maria Foti ◽  
Maria Vitale ◽  
Vittorio Fisichella ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Polymerase Chain Reaction ◽  
Small Ruminant ◽  
Meca Gene ◽  
Small Ruminants ◽  
Tetracycline Resistance ◽  
Chain Reaction ◽  
Toxin Genes ◽  
Pathogenic Factors ◽  
Polymerase Chain

Staphyloccoccus aureus is the major cause of mastitis in small ruminants in the Mediterranean farms causing severe losses to dairy industry. Antibiotic treatment has been the most common approach to control these infections. Aim of this study was to investigate antimicrobial resistance (AMR), virulence factors and biofilm-related genes of 84 Sicilian strains of S. aureus isolated from sheep and goats milk during two different periods δT1 (2006-2009) and δT2 (2013-2015). Kirby Bauer method and Polymerase Chain Reaction (PCR) were utilized to monitor AMR and related genes (mecA, tetK, tetM, ermA, ermC). Moreover, toxin genes (tsst-1, sea-see, seg-sej, and sep) and biofilm genes (bap, ica, sasC) were studied. Twenty-six isolates (30.9%) showed multidrug resistance. The two groups showed similar results with exception for higher values of resistance for tilmicosin and lower for sulfamethoxazole and vancomycin of the second group. MecA gene was detected in one isolate. Tetracycline resistance was higher than 20%, with an increase in δT2 group. Toxin genes were found in 5 isolates (5.9%), belonging of δT2 group, while 57 of isolates (67.8%) showed biofilm related genes. The high presence of multi-resistant isolates suggests the need of more responsible use of antibiotic therapy for the control of these infections.

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 β-lactam resistance in coagulase-negative Staphylococcus isolated from subclinical goat mastites

2021 ◽  
Vol 56 ◽  
Author(s):  
Amanda Pereira Lucas ◽  
Elizabete Cristina da Silva ◽  
Andriele Renata Barbosa de Farias ◽  
Maria Priscilla Borges de Albuquerque ◽  
Luciana Florêncio Vilaça Lopes ◽  
...  
Keyword(s):  
Meca Gene ◽  
Resistance Mechanisms ◽  
Disk Diffusion ◽  
Penicillin Resistance ◽  
Coagulase Negative Staphylococcus ◽  
Poor Agreement ◽  
Chain Reaction ◽  
Resistance To Penicillin ◽  
Polymerase Chain ◽  
Phenotypic Methods

Abstract: The objective of this work was to evaluate resistance mechanisms to β-lactam antimicrobials in 251 strains of coagulase-negative Staphylococcus (CoNS) isolated from subclinical goat mastitis, as well as to determine the sensitivity and specificity of the nitrocefin and disk diffusion methods to detect penicillin resistance, in comparison with the polymerase chain reaction (PCR). The isolates were evaluated for the presence of the blaZ and mecA genes, β-lactamase production, and susceptibility to penicillin. Of the total isolates, 228 (91%) carried the blaZ gene and, among these, 144 (63%) were positive for β-lactamase production. Resistance to penicillin was observed in 125 of the isolates, of which 96.8% carried the blaZ gene. The sensitivity of the phenotypic methods to detect β-lactamase production was low, but their specificity was high; the Kappa coefficient showed a poor agreement between the phenotypic methods and PCR. The mecA gene was detected in only 3% of the isolates, which were identified as belonging to the species: S. capitis subsp. ureolyticus, S. caprae, S. warneri, S. sciuri, S. simulans, and S. cohnii subsp. urealyticum. Coagulase-negative Staphylococcus are important mastitis-causing pathogens in goat and harbor the blaZ and mecA genes related to resistance to β-lactam antimicrobials. The sensitivity of the nitrocefin and disk diffusion methods to detect penicillin resistance is low in relation to that of PCR.

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