Evaluation of a disk diffusion method with cefoxitin (30��g) for detection of methicillin-resistant Staphylococcus aureus

Author(s):  
H. Van Landuyt ◽  
B. Cauwelier ◽  
B. Gordts ◽  
P. Descheemaecker
Author(s):  
Abolfazl Jafari-Sales ◽  
Zahra Sadeghi Deylamdeh ◽  
Afsoon Shariat

Introduction: Staphylococcus aureus causes a wide range of infections and as a multivalent pathogen is one of the causative agents of nosocomial and community infections. Therefore, the aim of this study was to identify and determine the pattern of antibiotic resistance of methicillin-resistant Staphylococcus aureus (MRSA) isolates from patients in hospitals and medical centers in Marand city and also to evaluate the presence of mecA gene. Materials and Methods: In this cross-sectional descriptive study, 385 samples of S. aureus were collected from different clinical samples of patients in hospitals and medical centers of Marand city. S. aureus was identified using standard biochemical methods.  Methicillin resistance was determined by disk diffusion method in the presence of oxacillin and cefoxitin. The pattern of antibiotic resistance of the strains was determined by disk diffusion method and according to CLSI recommendation and also PCR method was used to evaluate the frequency of MecA gene. Results: In the present study, out of 385 samples of S. aureus, 215 (55.84%) samples were methicillin resistant. PCR results for mecA gene showed that 110 samples had mecA gene.  The highest antibiotic resistance was observed against penicillin (100%) and erythromycin (83.63%). Most MRSA were isolated from urine and wound samples. Conclusion: The results of this study indicate the prevalence of methicillin-resistant species and also the increase in antibiotic resistance of MRSA to various antibiotics.  Therefore, in order to prevent increased resistance to other antibiotics, it is recommended to avoid inappropriate use of antibiotics.


Antibiotics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 375
Author(s):  
Vanessa Silva ◽  
Sara Hermenegildo ◽  
Catarina Ferreira ◽  
Célia M. Manaia ◽  
Rosa Capita ◽  
...  

In this study we aimed to characterize antimicrobial resistance in methicillin-resistant Staphylococcus aureus (MRSA) isolated from bloodstream infections as well as the associated genetic lineages of the isolates. Sixteen MRSA isolates were recovered from bacteremia samples from inpatients between 2016 and 2019. The antimicrobial susceptibility of these isolates was tested by the Kirby–Bauer disk diffusion method against 14 antimicrobial agents. To determine the macrolide–lincosamide–streptogramin B (MLSB) resistance phenotype of the isolates, erythromycin-resistant isolates were assessed by double-disk diffusion (D-test). The resistance and virulence genes were screened by polymerase chain reaction (PCR). All isolates were characterized by multilocus sequence typing (MLST), spa typing, staphylococcal chromosomal cassette mec (SCCmec) typing, and accessory gene regulator (agr) typing. Isolates showed resistance to cefoxitin, penicillin, ciprofloxacin, erythromycin, fusidic acid, clindamycin, and aminoglycosides, confirmed by the presence of the blaZ, ermA, ermC, mphC, msrA/B, aac(6’)-Ie-aph(2’’)-Ia, and ant(4’)-Ia genes. Three isolates were Panton–Valentine-leukocidin-positive. Most strains (n = 12) presented an inducible MLSB phenotype. The isolates were ascribed to eight spa-types (t747, t002, t020, t1084, t008, t10682, t18526, and t1370) and four MLSTs (ST22, ST5, ST105, and ST8). Overall, most (n = 12) MRSA isolates had a multidrug-resistance profile with inducible MLSB phenotypes and belonged to epidemic MRSA clones.


2012 ◽  
Vol 45 (2) ◽  
pp. 189-193 ◽  
Author(s):  
Karinne Spirandelli Carvalho Naves ◽  
Natália Vaz da Trindade ◽  
Paulo Pinto Gontijo Filho

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) is spread out in hospitals across different regions of the world and is regarded as the major agent of nosocomial infections, causing infections such as skin and soft tissue pneumonia and sepsis. The aim of this study was to identify risk factors for methicillin-resistance in Staphylococcus aureus bloodstream infection (BSI) and the predictive factors for death. METHODS: A retrospective cohort of fifty-one patients presenting bacteraemia due to S. aureus between September 2006 and September 2008 was analysed. Staphylococcu aureus samples were obtained from blood cultures performed by clinical hospital microbiology laboratory from the Uberlândia Federal University. Methicillinresistance was determined by growth on oxacillin screen agar and antimicrobial susceptibility by means of the disk diffusion method. RESULTS: We found similar numbers of MRSA (56.8%) and methicillin-susceptible Staphylococcus aureus (MSSA) (43.2%) infections, and the overall hospital mortality ratio was 47%, predominantly in MRSA group (70.8% vs. 29.2%) (p=0.05). Age (p=0.02) was significantly higher in MRSA patients as also was the use of central venous catheter (p=0.02). The use of two or more antimicrobial agents (p=0.03) and the length of hospital stay prior to bacteraemia superior to seven days (p=0.006) were associated with mortality. High odds ratio value was observed in cardiopathy as comorbidity. CONCLUSIONS: Despite several risk factors associated with MRSA and MSSA infection, the use of two or more antimicrobial agents was the unique independent variable associated with mortality.


2021 ◽  
Vol 30 (1) ◽  
pp. 109-114
Author(s):  
Nancy M. Attia ◽  
Abeer Abd El Rahim Ghazal ◽  
Omnia M. Khaleel ◽  
Ahmed Gaballah

Background: Methicillin-resistant Staphylococcus aureus (MRSA) colonization is considered a major risk factor for nosocomial infections and its decolonization has reduced these infections. Mupirocin (MUP) is the topical antibiotic of choice for decolonization. MUP decolonization failure is attributed to MUP resistance. Objective: The aim of the current study is to assess MUP resistance among MRSA isolates phenotypically and genotypically. Methodology: Fifty MRSA isolates were identified in Microbiology Department in the Medical Research Institute hospital, Alexandria University. Antibiotic susceptibility to different classes of antibiotics by disk diffusion method was done. MUP minimum inhibitory concentration (MIC) was determined phenotypically by MUP Ezy MIC™ Strips. MUP resistance was determined genetically by multiplex PCR detection of mupA and mupB. Results: Of all MRSA isolates, 6% exhibited high level and none showed low level MUP resistance. Only mupA was detected in all resistant isolates. Conclusion: Despite low prevalence of MUP resistance, it is appropriate to test MUP resistance prior nasal decolonization


2021 ◽  
Vol 4 (1) ◽  
pp. 56
Author(s):  
Shinta Levea Ni'matul Fadlilah ◽  
Mustofa Helmi Effendi ◽  
Wiwiek Tyasningsih ◽  
Lucia Tri Suwanti ◽  
Jola Rahmahani ◽  
...  

This study aimed to determine the in vitro antibacterial activities of essential oil from cinnamon bark (Cinnamomum burmannii) on Methicillin-resistant Staphylococcus aureus (MRSA) isolated from raw milk. Essential oil from cinnamon bark obtained from the steam distillation method and essential oil was made in a series dilution with a concentration of 1%, 2%, 4%, and 8%. The antibacterial activities were tested using the disk diffusion method. Results showed from five isolates of MRSA, one isolate was sensitive of essential oil with a concentration 2% and all of the isolate was sensitive with a concentration 4% and 8%. The antibacterial activity showed by inhibition zones on  MRSA. The results suggest that the activity of the essential oils of cinnamon bark has an antibacterial effect on MRSA and it is developed as phytopharmaca.


Foods ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 439 ◽  
Author(s):  
Vanessa Silva ◽  
Telma de Sousa ◽  
Paula Gómez ◽  
Carolina Sabença ◽  
Madalena Vieira-Pinto ◽  
...  

Methicillin-resistant Staphylococcus aureus (MRSA) are one of the main pathogens associated with purulent infections. MRSA clonal complex 97 (CC97) has been identified in a wide diversity of livestock animals. Therefore, we aimed to investigate the antibiotic resistance profiles of MRSA strains isolated from purulent lesions of food-producing rabbits. Samples from purulent lesions of 66 rabbits were collected in a slaughterhouse in Portugal. Samples were seeded onto ORSAB plates with 2 mg/L of oxacillin for MRSA isolation. Susceptibility to antibiotics was tested by the disk diffusion method against 14 antimicrobial agents. The presence of resistance genes, virulence factors and the immune evasion cluster (IEC) system was studied by polymerase chain reaction. All isolates were characterized by multilocus sequence typing (MLST), agr and spa typing. From the 66 samples analyzed, 16 (24.2%) MRSA were detected. All strains were classified as multidrug-resistant as they were resistant to at least three classes of antibiotics. All isolates showed resistance to penicillin, erythromycin and clindamycin. Seven isolates were resistant to gentamicin and harbored the aac(6′)-Ie-aph (2″)-Ia gene. Resistance to tetracycline was detected in 10 isolates harboring the tet(K) gene. The IEC genes were detected in three isolates. MRSA strains belonged to CC97, CC1, CC5, CC15 or CC22. The isolates were assigned to six different spa types. In this study we found a moderate prevalence of multidrug-resistant MRSA strains in food-producing rabbits. This may represent concern for food safety and public health, since cross-contamination may occur, leading to the spread of MRSA and, eventually, the possibility of ingestion of contaminated meat.


Author(s):  
Tasneem Siddiqui ◽  
Rafat Shamim ◽  
Sangram Singh Patel ◽  
Chinmoy Sahu

Introduction: Levonadifloxacin is a novel antibiotic belonging to the benzoquinolizine subclass of fluoroquinolone with potent activity against Methicillin Resistant Staphylococcus aureus (MRSA) and Quinolone Resistant Staphylococcus aureus (QRSA). Both intravenous levonadifloxacin and its oral formulation have recently been approved in India for the treatment of acute bacterial skin related infections. Aim: To assess the activity of levonadifloxacin against gram positive clinical isolates collected from Intensive Care Units (ICUs) using the disk-diffusion method. Materials and Methods: The present descriptive study where non duplicate isolates of Staphylococcus aureus (S. aureus) and other gram positive isolates from various clinical samples from all Intensive Care Units (ICUs) were collected from June to December 2020 and subjected to levonadifloxacin susceptibility testing (disk diffusion method) as per the Clinical and Laboratory Standards Institute (CLSI) guidelines, 2020. Data analysis was performed using Statistical Package for the Social Sciences (SPSS) software, version 25.0. Results: A total of 142 gram positive clinical isolates collected from all ICUs of the hospital were analysed. These isolates included coagulase negative S. aureus 109 (76.8%), S. aureus 21 (14.8%) and Enterococcus faecalis 12 (8.4%). All the gram positive isolates of the study were susceptible to levonadifloxacin as per the prespecified interpretive criteria identified based on population pharmacokinetic model and Monte Carlo simulation enabled probability of pharmacodynamic target attainment analysis. Conclusion: Results of this in vitro study shows good activity of levonadifloxacin against gram positive isolates including difficult to-treat methicillin resistant staphylococcal isolates collected from ICU patients.


Author(s):  
Sheetal Sharma ◽  
Preeti Srivastava ◽  
Anjali Kulshrestha ◽  
Ameer Abbas

Background: Rapid and accurate detection of methicillin resistant Staphylococcus aureus (MRSA) is an important role of clinical microbiology laboratories to avoid treatment failure. The aim of this study was to compare conventional methods against the cefoxitin disc diffusion method to determine the best phenotypic method. Methods: Study was carried out in the Department of Microbiology, National Institute of Medical Sciences & Research, Jaipur (India), between July 2016 – December 2016. The methods included were Oxacillin E-test MIC, Oxacillin screen agar, Oxacillin disk diffusion, Cefoxitin disk diffusion and CHROMagar- MRSA methods. Antimicrobial susceptibility performed as per CLSI guidelines.Results: Out of 142 isolates of S. aureus, fifty three (37.32%) strains of MRSA were isolated from clinical specimen. E-MIC test was selected as gold standard method. The sensitivity and specificity of Oxacillin screen agar and CHROMagar-MRSA were same 98.07% and 97.80%, respectively. The sensitivity and specificity of oxacillin disk diffusion were 94.23% and 98.89%. Fifty three strains of S. aureus were MRSA by cefoxitin disk diffusion method and Oxacillin Ezy MIC test. The sensitivity and specificity of cefoxitin disk diffusion method and Oxacillin Ezy MIC method was 100% and 100% respectively. All isolates including MRSA were susceptible to Vancomycin and Linezolid. Conclusions: All phenotypic methods had high sensitivity and specificity for detection of MRSA. However, cefoxitin disk diffusion method in comparison to other methods had higher sensitivity and specificity. 


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