LEVELS OF VANCOMYCIN SUSCEPTIBILITY AMONGST ISOLATED Staphylococcus aureus STRAINS IN A TERTIARY CARE HOSPITAL (original) (raw)
Related papers
2018
DOI: 10.21276/sjpm.2018.3.10.16 Abstract: Staphylococcus aureus is one of the most common causes of Blood Stream infections (BSI), skin and wound infections, osteomyelitis, endocarditis, and nosocomial infections, especially pneumonia, surgical site infections (SSI), and continue to be a major cause of community-acquired infections. Methicillin Resistant Staphylococcus aureus (MRSA) is an important cause of community and hospital acquired infections. MRSA are mainly nosocomial and are increasingly reported from many countries worldwide. The purpose of present study was to determine the sensitivity of S. aureus isolated from infected patients to methicillin and to evaluate the possible presence of VRSA in our tertiary care hospital. Staphylococci were isolated and identified by standard microbiological procedures. Methicillin resistance was detected by using cefoxitin (30 μgm) by disc diffusion method. MRSA strains detected were then subjected to vancomycin agar screen test and E tes...
Panacea Journal of Medical Sciences
Staphylococcus aureus infections in current times have become challenging to treat because of advent of Methicillin Resistant Staphylococcus aureus (MRSA) strains which are concurrently resistant to a wide panel of drugs and posing a threat to clinicians and microbiologists globally. The optimal drug for treatment of such MRSA infections is vancomycin but strains with augmented Minimum Inhibitory concentration (MIC) for this drug also have surfaced. Objectives: To know the frequency of MRSA isolates in various clinical samples with their antimicrobial sensitivity patterns and to equate agar dilution and E-test methods for MIC determination of vancomycin to MRSA strains. Materials and Methods: A total of 50 non repeat clinical isolates of staphylococcus aureus isolates were collected from various clinical specimens and were tested for methicillin resistance using the cefoxitin disc diffusion test (30µg). All MRSA isolates were tested for specific MIC by agar dilution and E-test methods. Results: 29 (58%) isolates were resistant to cefoxitin (MRSA). 13.8% isolates had MIC of 4µg/ml for vancomycin (VISA) by both agar dilution and E-test methods. However by agar dilution method 25 (86.2%) isolates exhibited vancomycin MIC of ≤ 2 µg/ml and by E-test 68.9% of the isolates showed MIC ≤ 2 µg/ml. Conclusion: Multidrug resistant MRSA strains are on the rise and alternate drug of choice for these infections; vancomycin also is showing increased MIC so prudent use of this drug is advocated. E-test can detect MRSA strains with intermediate MIC values useful for detection of MIC creep so that vancomycin can be used rationally.
IP Innovative Publication Pvt. Ltd., 2018
Introduction: Staphylococcus is a major pathogen of community and hospital acquired infections. Vancomycin is used in MRSA caused infections. Emergence of VISA and VRSA has been of great concern in clinical aspects. Materials and Methods: All clinical samples were processed in the laboratory according to standard procedure. Inoculated plates were incubated at 37? C for 24-48 hours. Only S. aureus isolates were included in the present study. Antibiotic susceptibility testing was done by Kirby-Bauer disc diffusion method using a panel of drugs. Cefoxitin disc was used to identify methicillin resistance. The MIC of vancomycin for MRSA isolates was carried out by Agar dilution method and E-test according to standard methods. Heteroresistance to vancomycin was detected by using BHI screen agar. Results: 190 S. aureus were isolated from various clinical samples. Most of the isolates were resistant to amoxyclav (96.2%) followed by ciprofloxacin (84.2%), erythromycin (33.2%), Clindamycin (31.2%), Cotrimoxazole (14.6%), Teicoplanin (4.2%), Mupirocin (2.1%) and none of the isolates were resistant to linezolid. Out of 190 S. aureus isolates, 97 (51.1%) were identified as MRSA. None of the isolates were resistant to vancomycin by agar dilution method and E-test method. Four out of 97 (4.1%) MRSA isolates showed intermediate susceptibility to vancomycin. Among the isolates with MIC of 2µg/ml, 5 (19.2%) showed heteroresistance to vancomycin by BHI screen agar method. Conclusion: Rapid identification of patients harboring VRSA, VISA or hVISA and adherence to infection control protocols are very important in controlling the dissemination of these pathogens. Keywords: MRSA, VISA, VRSA, Heterointermediate resistant Staphylococcus aureus (hVISA), Agar dilution method, E-test.
https://www.ijhsr.org/IJHSR\_Vol.7\_Issue.1\_Jan2017/IJHSR\_Abstract.010.html, 2017
Background: Staphylococcus aureus is one of the most common causes of nosocomial infections. Vancomycin is the drug of choice to treat infections caused by MRSA. Objectives: The study determines Vancomycin MIC of MRSA strains by both agar dilution and Vitek methods. Presence of VAN a gene was also determined. Materials and Methods: Study was conducted from April 2015-March 2016.A total 70 Staphylococcus aureus strains were included. Methicillin resistance was determined by using Cefoxitin disc (30ug) as per CLSI guidelines. Vancomycin resistance was detected by both agar dilution and Vitek methods. PCR was done to determine presence of VAN A gene among VISA strains. Results: Among 70 S.aureus strains, 40 (57%) strains were methicillin resistant. Maximum MRSA strains (55%) were isolated from pus samples. 6 VISA (Vancomycin intermediate S. aureus strains) strains were detected by agar dilution method. Vitek was able to detect 3 VISA strains. All VISA strains were sensitive to Rifampicin and Linezolid by disc diffusion method. All VISA strains were negative for VAN A gene by PCR. Conclusion: Disc diffusion method misclassifies vancomycin intermediate isolates as fully susceptible strains. Clinical laboratories must perform MIC method to correctly identify VISA strains and avoid treatment failure.
Romanian Review of Laboratory Medicine, 2014
The clinical relevance of Staphylococcus aureus strains with heterointermediate susceptibility to vancomycin (hVISA) is still controversial, however they could be responsible for treatment failures in patients treated with vancomycin. The lack of standardization and the complexity of testing methods are the main challenge in indentifying such strains. The aim of our study was to evaluate the frequency of hVISA strains in Targu-Mures Clinical Emergency Hospital. One hundred twenty-two, non-duplicate, methicillin-resistant S. aureus (MRSA) isolates susceptible to vancomycin using standard E-test (MIC≤2 mg/L) were screened for heteroresistance with Glycopeptide Resistance Detection test (E-test GRD). Population analysis profile-area under the curve (PAP/AUC) method was used for confirmation. Twenty-four strains (19.5%) were found positive with the screening method. Two of them (1.63%) were confirmed having hVISA phenotype and no strains with intermediate vancomycin susceptibility (VISA) were detected. In conclusion, the rate of MRSA strains with reduced vancomycin susceptibility was low. However, their monitoring may be useful, taking into consideration the wide usage of glycopeptides in the treatment of serious MRSA infections.
Journal of Nepal Medical Association, 2014
Introduction: Methicillin resistant Staphylococcus aureus (MRSA), majorly associated with nosocomial and community infections worldwide, are emerging as resistant strains to many antibiotics narrowing down the efficacy of antimicrobial therapy. In order to investigate the changing resistant pattern of MRSA to empirical drugs, the study was carried out at KIST Medical College and Hospital, Nepal. It also aims to determine the minimum inhibitory concentration of vancomycin among MRSA. Methods: Altogether 3500 clinical samples including 1303 blood, 1489 urine and 708 body fluids were collected and processed. Isolated S. aureus were further screened for methicillin resistance by Kirby-Bauer disk diffusion technique using cefoxitin (30μg) disk. All MRSA were subjected to in vitro determination of MIC of vancomycin by agar dilution method as recommended by CLSI guidelines. Results: Total 287 S. aureus were isolated from the different clinical samples. Altogether 248 (86.41%) were found to...
2016
Introduction: Vancomycin, a glycopeptide antibiotic had been considered to be the drug of choice for methicillin resistance Staphylococcus aureus. In MSSA infection, Injudicious and infrequent use of vancomycin has resulted in emergence of the strains with higher vancomycin MIC. Vancomycin MIC is a gold standard test to determine the sensitive(≤2 μg/ml), intermediate (4-8 μg/ml) or resistant (≥16 μg/ml) S. aureus strains, according to the CLSI guidelines. Material and methods: The current study was a comparative study to determine Vancomycin MIC value in MRSA and MSSA. Total 53 Staphylococcus aureus (S. aureus) strains were screened for methicillin resistance using a 30 μg cefoxitin disc (HiMedia, India) on Mueller Hinton agar according to Clinical and Laboratory Standards Institute (CLSI) guideline. Vancomycin MIC (minimum inhibitory concentration) was determined by agar dilution method. Observation: Out of 53 S. aureus isolates, 42 (79%) were methicillin resistant S. aureus (MRSA)...
Journal of Basic Research in Medical Sciences, 2016
Introduction: In this study, using the phenotypic and genotypic methods, oxacillin susceptibility in Staphylococcus aureus (S. aureus) strains isolated from patients at two government hospitals in Ilam, Iran was tested. Materials and methods: Out of 200 S. aureus isolates from different human clinical specimens consisting of blood (31%), wound (20%), urine (21%), catheters (7%), sputum (12%), others (9%) were collected. The methicillin resistant S. aureus isolates were investigated using disk diffusion methods and oxacillin (1μg) and cefoxitin (30μg), on Mueller-Hinton agar were used, and MecA and vanA genes were detected by PCR. In addition, the isolates were tested for their antibiogram profiles. Results: Among 200 S. aureus strains included in this study, 35.96% were MRSA. The percentage of resistance by disk diffusion method was as below: penicillin 85.96%, vancomycin 0%, ampicillin 87.71%, gentamicin 48.25% erythromycin 54.25%, clindamycin 32.45%, amikacin 21.05%, ciprofloxacin 42.10%, tetracycline 51.75% and co-trimoxazole 42.10%. Phenotyping method by disk diffusion method using oxacillin and cefoxitin for detecting of MRSA showed sensitivity and specificity of about 33.33% and 35.96%, respectively. Presence of MecA and vanA genes in MRSA isolates by PCR were 35.96% and 0%, respectively. The oxacillin and cefoxitin disk diffusion methods showed 92.68% and 100% sensitivity, respectively, and 98.8% specificity. Conclusion: Our finding showed that, the cefoxitin disk diffusion method is better in compared to the oxacillin disk diffusion similar to results from detecting of MecA gene in PCR as a golden test.
https://www.ijrrjournal.com/IJRR\_Vol.5\_Issue.9\_Sep2018/Abstract\_IJRR0020.html, 2018
Introduction: Resistance to methicillin and other β-lactamase resistant penicillins was first observed in Staphylococcus aureus soon after methicillin was introduced into clinical use in Britain in 1961. Methicillin resistant S. aureus (MRSA) is responsible for around 30% or more of all S. aureus infections. MRSA is a multidrug resistant organism that threatens the continued effectiveness of antibiotics worldwide and causes a threat in hospitals and long-term care settings. Vancomycin has been the treatment of choice for serious infections caused by MRSA. But there has been uncertainty regarding the method for detection of minimum inhibitory concentration of vancomycin, clinical relevance of reduced vancomycin susceptibility in S. aureus & increasing concern regarding the efficacy of vancomycin for treatment of MRSA infections. Materials and Methods: A study was planned to determine the prevalence of methicillin resistance in clinical isolates of S. aureus isolated from samples of patients attending OPDs & IPDs of Career Institute of Medical Sciences, Lucknow. Antimicrobial susceptibility testing was performed by Kirby Bauer disc diffusion method. The isolates were tested for methicillin resistance by using cefoxitin disc (30µg) by disc diffusion method. The results were interpreted according to CLSI criteria. Vancomycin MICs were compared by two methods viz. E TEST & VITEK 2. Results: A total of 163 isolates were studied and 66(40.4%) were found to be methicillin resistant. MRSA isolates showed greater resistance to multiple drugs as compared to methicillin sensitive S. aureus (MSSA) isolates. 48.48%, 86.36%, and 42.42% of MRSA were resistant to chloramphenicol, cotrimoxazole & doxycycline as compared to 4.12%, 15.46% & 12.37% of MSSA respectively. On determination of MICs for vancomycin for the MRSA isolates, all were identified as VSSA by E Test & Vitek 2 methods but the MIC values were variable on testing with both methods. Out of 66 isolates, 51 isolates had MIC=1.5µg/mL & 15 isolates had MIC = 2 µg/mL by E Test method. When these isolates were tested with Vitek 2, only 20 had MIC=1.5µg/mL while 46 had MIC=2µg/mL. Conclusion: An ever rising isolation of MRSA from various infections was observed. These isolates were also associated with high level of co-resistance to other group of antibiotics. There is a need to study the epidemiology of such infections. Robust antimicrobial stewardship and strengthened infection control measures are required to prevent spread and reduce emergence of resistance.
Journal of the Medical Association of Thailand = Chotmaihet thangphaet, 2014
Staphylococcus aureus is a species of bacteria that causes a number of diseases and more than 60% of it is presently resistant to methicillin. Vancomycin is the drug of choice for the eradication of methicillin-resistant S. aureus (MRSA). This study aimed to investigate the susceptibility of heterogeneous vancomycin intermediate S. aureus (hVISA) and vancomycin intermediate S. aureus (VISA) to vancomycin by standard disk diffusion, microbroth dilution, a one-point population assay, and a population analysis profile. Sixty-eight MRSA isolates from patients admitted to Sanprasitthiprasong Hospital between November 2010 and November 2011 were tested. Standard disk diffusion showed that all the MRSA isolates were susceptible to vancomycin. Vancomycin MICs for all isolates were 1-2 microg/mL. Only two MRSA isolates (2.9%) were able to grow on brain heart infusion agar supplemented with vancomycin 4 microg/mL and were confirmed by a population analysis as hVISA. This study showed the effe...