scholarly journals Evaluation of Brilliance MRSA 2 Agar for Detection of Methicillin-Resistant Staphylococcus aureus in Clinical Samples: Table 1

2013 ◽  
Vol 51 (3) ◽  
pp. 1026-1027 ◽  
Author(s):  
J. Veenemans ◽  
C. Verhulst ◽  
R. Punselie ◽  
P. H. J. van Keulen ◽  
J. A. J. W. Kluytmans
2021 ◽  
Vol 14 (5) ◽  
pp. 420
Author(s):  
Tanveer Ali ◽  
Abdul Basit ◽  
Asad Mustafa Karim ◽  
Jung-Hun Lee ◽  
Jeong-Ho Jeon ◽  
...  

β-Lactam antibiotics target penicillin-binding proteins and inhibit the synthesis of peptidoglycan, a crucial step in cell wall biosynthesis. Staphylococcus aureus acquires resistance against β-lactam antibiotics by producing a penicillin-binding protein 2a (PBP2a), encoded by the mecA gene. PBP2a participates in peptidoglycan biosynthesis and exhibits a poor affinity towards β-lactam antibiotics. The current study was performed to determine the diversity and the role of missense mutations of PBP2a in the antibiotic resistance mechanism. The methicillin-resistant Staphylococcus aureus (MRSA) isolates from clinical samples were identified using phenotypic and genotypic techniques. The highest frequency (60%, 18 out of 30) of MRSA was observed in wound specimens. Sequence variation analysis of the mecA gene showed four amino acid substitutions (i.e., E239K, E239R, G246E, and E447K). The E239R mutation was found to be novel. The protein-ligand docking results showed that the E239R mutation in the allosteric site of PBP2a induces conformational changes in the active site and, thus, hinders its interaction with cefoxitin. Therefore, the present report indicates that mutation in the allosteric site of PBP2a provides a more closed active site conformation than wide-type PBP2a and then causes the high-level resistance to cefoxitin.


2009 ◽  
Vol 48 (175) ◽  
Author(s):  
Bidya Shrestha ◽  
B M Pokhrel ◽  
T M Mohapatra

Introduction: Methicillin resistant Staphylococcus aureus (MRSA), the most common cause ofnosocomial infection has been a major cause of morbidity and mortality around the world. They arenormally resistant to most of the antibiotics used in clinical practice. This study has been carried outto fi nd out the resistance pattern among S. aureus.Methods: During November 2007 to June 2008, clinical samples from patients with nosocomialinfection were processed for culture and sensitivity following standard methodology in microbiologylaboratory, Tribhuvan University teaching hospital, Kathmandu, Nepal.Results: Among 149 Staphylococcus aureus isolates, highest resistance was observed against Penicillin(91.94%) followed by Fluoroquinolone (61.74%), Erythromycin (52.94%), Gentamicin (46.98%),Cotrimoxazole (42.95%), Tetracycline (40.94%) and others, whereas susceptibility was observedmaximum against Chloramphenicol (94.85%) followed by Rifampicin (92.61%), Tetracycline(59.06%), Cotrimoxazole (57.04%), and others. None of the isolates were resistant to Vancomycinand Teicoplanin. Of these isolates 44.96 % of the isolates were Methicillin resistant S. aureus (MRSA).Resistance to Penicillin, Fluoroquinolone, Erythromycin, Gentamicin, Co-trimoxazole and Tetracyclinewere associated signifi cantly with MRSA isolates (X2= 8.779, p<0.05, X2= 74.233, p<0.05, X2= 84.2842,p<0.05, X2= 108.2032, p<0.05, X2= 88.1512, p<0.05 and X2= 79.1876, p<0.05 respectively). Althoughmost of the Methicillin sensitive S. aureus (MSSA) isolates were susceptible to both Rifampicinand Chloramphenicol, only Rifampicin susceptibility was signifi cantly associated with them (X2=10.1299, p<0.05). Among three Biochemical tests for the detection of β lactamase detection namelychromogenic, iodometric and acidimetric test, chromogenic test method had highest sensitivity andspecifi city.Conclusions: Since MRSA comprised a greater part of S. aureus isolates and were multi-resistant,patients infected by such strains should be identifi ed and kept in isolation for hospital infectioncontrol and treated with second line of drug like vancomycin.Key Words: β lactamase, methicillin resistant Staphylococcus aureus,methicillin sensitive Staphylococcus aureus, resistance pattern


2019 ◽  
Author(s):  
Raja Ram Gurung ◽  
Prashanna Maharjan ◽  
Ganga GC

Abstract Background: Staphylococcus aureus is one of the important superbugs distributed throughout the world. It causes minor skin infections to severe complications including nosocomial infections in both hospitals and community settings. These strains have multi-drug resistant property. Hence, they are difficult to manage which increase health-related costs and simultaneously intensifying the need for new antibiotics. The extent of Methicillin-Resistant Staphylococcus aureus (MRSA) in children is largely unknown. The study determines the current status of S. aureus and MRSA causing various infections in pediatric patients visiting International Friendship Children’s Hospital (IFCH). Methods: A cross-sectional study was conducted among patients visiting a hospital. Various clinical specimens were aseptically collected and processed according to standard microbiological procedures. Isolation and identification of S. aureus were done by microscopy, mannitol fermentation, and coagulase positivity. All identified S. aureus isolates subjected to in-vitro antibiogram by Kirby-Bauer disc diffusion technique adopting Clinical and Laboratory Standards Institute (CLSI) guideline. Isolates resistant to cefoxitin were considered to be MRSA. Whereas, isolates produced D-shaped inhibition zone around clindamycin when kept near erythromycin were considered to be Inducible Clindamycin Resistant (ICR). Results: 672 various types of clinical samples were processed from the microbiology laboratory from June and November 2015. Out of 300 culture positive samples, 52 (17.3%) were S. aureus isolates, among them 39 (75.0%) were found to be MRSA. The D-test showed that Macrolide-Lincosamide-Streptogramin-B (MLSB) phenotype was 15.4%. Conclusion: The study shows the MRSA occurrence is prevalent in pediatric patients and newer classes’ drugs are found more effective than β-lactam drugs to treat S. aureus infection. However, restriction on the indiscriminate use of such drugs may be an effective strategy to control the drug resistance. Keywords: Methicillin-Resistant Staphylococcus aureus (MRSA), Macrolide-Lincosamide-Streptogramin B (MLSB) phenotype, Inducible Clindamycin Resistant (ICR) test or D-zone test, Antibiotic resistance, Nepal


2016 ◽  
Vol 5 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Ganesh Kumar Singh ◽  
Bigu Kumar Chaudhari ◽  
Kamal Prasad Parajuli

Background Resistance to antimicrobial agents is prevalent among Staphylococci. This has led to wide uses of macrolide-lincosamide-streptogramin B (MLSB) antibiotics to Staphylococcus aureus (S. aureus) infections. MLSB though chemically distinct, have similar target site and mode of action. The multiple mechanisms are responsible for resistance to MLSB antibiotics which can lead to clinical failure. The aim of the study was to investigate the frequency of inducible and constitutive clindamycin resistance among clinical isolates of S. aureus and their relationship with Methicillin-resistant Staphylococcus aureus (MRSA).Material & Methods A total of 336 unique Staphylococcus aureus isolates from different clinical samples obtained from patients were studied. Antibiotic susceptibility test was performed by Kirby- Bauer disc diffusion method. “D test” was performed to detect inducible clindamycin resistance as per CLSI guidelines. MRSA was detected using Cefoxitin (30μg) and results were interpreted according to CLSI criteria.Results Inducible clindamycin resistance was seen in 45 (13.39%), constitutive clindamycin resistance was seen among 58 (17.26%) while MS phenotype was observed among 38(11.30%) of isolates. Inducible resistance as well as constitutive resistance was higher among MRSA as compared to MSSA (21.11%, 4.48% and 21.11%, 12.82%respectively).Conclusion The Successful use of clindamycin for the treatment of infection caused by S. aureus can be predicted based on the result of simple and inexpensive D test.Journal of Nobel Medical CollegeVolume 5, Number 1, Issue 8, January-July 2016, 1-5


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