scholarly journals Methicillin-Resistance in Staphylococcus aureus Is Not Affected by the Overexpression in Trans of the mecA Gene Repressor: A Surprising Observation

PLoS ONE ◽  
2011 ◽  
Vol 6 (8) ◽  
pp. e23287 ◽  
Author(s):  
Duarte C. Oliveira ◽  
Hermínia de Lencastre
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
In Trans ◽  
Surprising Observation

scholarly journals Isolation of Biofilm Producing Methicillin-Resistant Staphylococcus aureus from Hospitalized Orthopaedic Patients in Kano State, Nigeria

2021 ◽  
Vol 28 (1) ◽  
pp. 66-74
Author(s):  
D.A. Oche ◽  
U. Abdulrahim ◽  
A.S. Oheagbulem ◽  
B.O. Olayinka
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
Community Settings ◽  
Potential Threat ◽  
Orthopaedic Patients ◽  
Nasal Swabs ◽  
Public Health Challenge

Biofilm formation and resistance to methicillin are among the factors that makes Staphylococcus aureus a very important human pathogen in both health-care and community settings. This study investigated methicillin-resistance among biofilm-producing S. aureus isolated from 49 orthopaedic in-patients within a 3 months period. Wound swabs, nasal swabs, bed swabs and urine samples were collected from each patient. The samples were cultured and screened for presence of S. aureus while the micro-titre plate method was used to detect biofilm producing isolates. PCR technique was finally used to detect the presence of mecA gene in methicilin resistant S. aureus (MRSA) isolates. Findings reveal 14.8% of bacterial isolates were Staphylococcus aureus of which 96.4% were biofilm-producers. However, strong biofilm producers constitute 11.1%. The mecA gene was detected in 15.8% of the MRSA isolates. Therefore, MRSA among biofilm-producing S. aureus is a potential threat primarily to the community of National Orthopaedic Hospital Dala and a major public health challenge. Keywords: Biofilm, Methicillin-resistance Staphylococcus aureus (MRSA), mecA gene, Orthopaedic patient

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 Inhibition of Staphylococcus aureus LC 554891 by Moringa oleifera Seed Extract either Singly or in Combination with Antibiotics

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4583
Author(s):  
Gamal Enan ◽  
Abdul-Raouf Al-Mohammadi ◽  
Samir Mahgoub ◽  
Seham Abdel-Shafi ◽  
Eman Askar ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Essential Oils ◽  
Inhibitory Activity ◽  
Moringa Oleifera ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
Resistance Index ◽  
Aureus Strain ◽  
Rrna Gene ◽  
Bacterial Strains

Bacterial outbreaks caused by Staphylococcus aureus (S. aureus) are interesting due to the existence of multidrug resistant (MDR) isolates. Therefore, there is a need to develop novel ways to control such MDR S. aureus. In this study, some natural agents such as honey bee (HB), extracts of either Moringa oleifera seeds (MSE), or leaves (MLE) and essential oils of garlic, clove, and moringa were studied for their inhibitory activity against this S. aureus pathogen. About 100 food samples including beef luncheon (n = 25), potato chips (n = 50), and corn flakes (n = 25) were investigated for possible pollution with the S. aureus bacteria. The isolated bacteria suspected to belong S. aureus that grew well onto Baird–Parker agar (Oxoid) and shiny halo zones and positive coagulase reaction were selected and identified by API-Kits; all of them that were approved belong to S. aureus (18 strains). The sensitivity of the obtained 18 S. aureus bacterial strains to 12 antibiotics were evaluated; all of them were resistant to ofloxacin; however, other antibiotics tested showed variable results. Interestingly, the S. aureus No. B3 isolated from beef luncheon was resistant to 10 antibiotics out of 12 ones tested. Multiple antibiotic resistance index (MAR) of this S. aureus strain was about 83.3%. Therefore, its identification was confirmed by sequencing of a 16S rRNA gene which approved a successful biochemical identification carried out by API Kits and such strain was designated S. aureus LC 554891. The genome of such strain appeared to contain mecA gene encoding methicillin resistance; it was found to contain hla, hlb, tsst-1, and finbA that encode α-blood hemolysis, β-blood hemolysis, toxic shock syndrome gene, and fibrinogen-binding protein gene, respectively. In addition, the virulence factors viz. sea; seb; sec encoding enterotoxins were detected in the DNA extracted from S. aureus B3 strain. Aqueous extract of Moringa oleifera seeds (MSE) showed inhibitory activity against S. aureus LC 554891 better than that obtained by tetracycline, essential oils or HB. Minimum inhibitory concentration (MIC) of MSE was 20µg/mL. Instrumental analysis of MSE showed 14 bioactive chemical compounds. Combinations of both MSE and tetracycline showed distinctive inhibitory activity against S. aureus LC 554891 than that obtained by either tetracycline or MSE singly.

scholarly journals Mannitol Fermenting Methicillin-Resistant Coagulase Negative Staphylococci Isolated From Diabetic Foot Infections

2020 ◽  
Vol 11 (4) ◽  
pp. 6095-6101
Author(s):  
Samira Fattah Hamid ◽  
Aza Bahadeen Taha
Keyword(s):  
Staphylococcus Aureus ◽  
Diabetic Foot ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
Rrna Gene ◽  
Human Pathogens ◽  
Coagulase Negative Staphylococci ◽  
Mannitol Salt Agar ◽  
Methicillin Resistant ◽  
Diabetic Foot Infections

Detection of mannitol fermenting coagulase-negative staphylococci is frequently unnoticed when Staphylococcus aureus is screening in the laboratory. On the other hand, the emergence of coagulase-negative staphylococci as critical human pathogens need dependable methods for the identification of clinically significant coagulase-negative staphylococci to understand the epidemiology of infections caused by these bacteria. The study aimed to identify mannitol fermenting coagulase-negative staphylococci that assumed to be Staphylococcus aureus as they formed yellow colonies on Mannitol Salt agar plates. Samples were taken from eighty-four patients with diabetic foot infections. The specimen was cultured on Blood agar and Mannitol Salt agar. Mannitol fermenting coagulase-negative staphylococci isolates diagnosed through Vitek2 system then confirmed by detecting 16S rRNA gene and absence of the nuc gene. Antibiotic sensitivity and methicillin resistance were detected by Vitek2 system, then methicillin resistance was confirmed by Oxacillin Salt Agar Screen test and detection of the mecA gene. Out of 81 Staphylococcus isolated from foot and nose of diabetic foot patients, twenty isolates were mannitol fermenting coagulase-negative staphylococci, they related to following species; Staphylococcus haemolyticus, staphylococcus lentus, Staphylococcus xylosus, Staphylococcus lugdunensis, Staphylococcus hominis, Staphylococcus galinarum and Staphylococcus saprophyticus). The majority of them (85%) were phenotypically methicillin-resistant and genotypically harbouring mecA gene. 80% were resistant to Erythromycin, 70% to Clindamycin, 35% to Trimethoprim-Sulphamethoxazole, 30% to Gentamicin and Rifampicin, 15% to Levofloxacin and Teicoplanin. 30% expressed inducible clindamycin resistance.

scholarly journals Comparison of Cefoxitin and Oxacillin disc diffusion test for the detection of mecA mediated methicillin resistance in Staphylococcus aureus

2013 ◽  
Vol 7 (1) ◽  
pp. 07-10 ◽  
Author(s):  
Durdana Chowdhury ◽  
Sanya Tahmina Jhora ◽  
Shika Paul ◽  
Tarek Mahbub Khan ◽  
Mili Rani Saha ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Susceptibility Testing ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
Clinical Samples ◽  
Disc Diffusion ◽  
Standard Laboratory ◽  
Diffusion Test ◽  
Laboratory Procedure ◽  
Gold Standard Method

The study was designed to evaluate the efficacy of cefoxitin disc diffusion test to detect methicillin resistance in Staphylococcus aureus and compare it with oxacillin disc diffusion test and detection of mecA gene by PCR.  A total 116 S. aureus were isolated from clinical samples, collected from SSMC&MH, BIRDEM and NMC hospital, and was isolated by culture and identified by standard laboratory procedure. Antibiotic susceptibility testing was performed by oxacillin (1µg) and cefoxitin (30 µg) discs. PCR for amplification of mecA gene was performed as a gold standard method. Out of 116 isolates, 28 were PCR positive, 33 and 31 were oxacillin and cefoxitin resistant respectively. The sensitivity and specificity for the detection of MRSA was 100% and 94.31%inoxacillin disc diffusion test, and 96.42% and 95.45%in cefoxitin disc diffusion test respectively. Specificity is higher (95.45%) in cefoxitin disc diffusion test than oxacillin disc diffusion test in the detection of MRSA. Use of disc diffusion tests for both oxacillin and cefoxitin can help in more accurate prediction of methicillin resistance than single test, especially in centers which are not equipped to carry out more sophisticated tests for the detection of MRSA.DOI: http://dx.doi.org/10.3329/bjmm.v7i1.19314 Bangladesh J Med Microbiol 2013; 07(01): 7-10

scholarly journals Characteristics of Erythromycin Resistance in Methicillin-Resistant Staphylococcus aureus Isolated From Raw Milk

2019 ◽  
Vol 7 (4) ◽  
pp. 121-125
Author(s):  
Fatemeh Mahdavi ◽  
Fatemeh Zaboli ◽  
Rahem Khoshbakht
Keyword(s):  
Staphylococcus Aureus ◽  
Resistance Genes ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
Raw Milk ◽  
Erythromycin Resistance ◽  
Methicillin Resistant ◽  
Inducible Clindamycin Resistance ◽  
Mrsa Strains

Background: Methicillin-resistant Staphylococcus aureus (MRSA) strains are one of the most important multidrug resistant microorganisms that threaten human health. Objective: The present study was conducted to evaluate genotypic and phenotypic characteristics of erythromycin resistance among MRSA isolates recovered from raw milk in Iran. Materials and Methods: A total of 50 MRSA isolates were recovered from raw milk. Tests for erythromycin and clindamycin susceptibility and inducible clindamycin resistance were done. In addition, the presence of the methicillin resistance determinant (mecA), erythromycin resistance genes (ermA, ermB, ermC and msrA) and an important virulence gene (Panton– Valentine leukocidin) were investigated using polymerase chain reaction (PCR) method. Results: Forty-eight percent (24/50) and 46% (23/50) of the isolates were resistant to erythromycin and clindamycin, respectively. Seven (14%) isolates showed inducible clindamycin resistance phenotype. The mecA gene was detected in 88% (44/50) of MRSA isolates. The incidence of the ermA, ermB, ermC and msrA genes was 14%, 64%, 12%, and 26%, respectively and the PVL gene was present in 18% (9/50) of MRSA isolates. Conclusion: According to the results of the study, the incidence of erythromycin resistance genes and inducible clindamycin-resistant MRSA strains was high in raw milk samples in Iran.

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