scholarly journals Determination of MICs of Methicillin-resistant and Methicillin-susceptible Staphylococcus aureus Isolated from a Tertiary-care Hospital in Guyana

Author(s):  
Drovashti Seepersaud ◽  
Tereasia Ramlochan ◽  
Paul Cheddie

Objective: Previous studies done in the hospital setting in Guyana have shown that the frequency of isolation of methicillin-resistant Staphylococcus aureus isolates far exceeds the worldwide estimate of 50%. These past studies have been based on the use of the Kirby-Bauer disk diffusion methodology. The present study was conducted to determine the minimum inhibitory concentration of clinical isolates of methicillin-susceptible and methicillin-resistant S. aureus using the broth microdilution method. Design and Methods: A total of 101 consecutive, non-repetitive S. aureus isolates obtained from the GPHC medical lab during a six-week period were included in the study. These isolates were identified as MRSA and MSSA by laboratory personnel using the cefoxitin disk diffusion method. The oxacillin MICs for all isolates obtained were determined using prepared oxacillin broth microdilution trays with concentrations ranging from 4 μg/ml to 256 μg/ml. All results were interpreted according to CLSI guidelines. Results: The prevalence of MRSA at GPHC was found to be 65.35% with a majority of the isolates being high level oxacillin resistant strains with MICs > 256 μg/ml (84.85%). In our study, most resistant isolates were collected from patients admitted to the FSW (16.67%), Paediatric Wards (13.65%), MSW (13.64%), and FMW (12.12%). Additionally, 35 (79.55%) MSSA were suspected oxacillin susceptible with MIC < 4 μg/ml. The relationship between the cefoxitin disc diffusion and oxacillin broth microdilution results was found to be statistically significant with a p < 0.001. Conclusion: Methicillin-resistance continues to be a major problem in the hospital setting, and this study has should that commonly used conventional techniques are unlikely to identify all of the potentially resistant isolates. Recommendation: The high prevalence and high oxacillin MIC of MRSA at GPHC suggests that more emphasis should be placed on infection control and surveillance programs within the hospital setting.

Author(s):  
Paul Cheddie ◽  
Drovashti Seepersaud ◽  
Tereasia Ramlochan

Background and Aim: Methicillin-resistant Staphylocccus aureus (MRSA) continues to be a major problem globally. Previous data had suggested that the prevalence of MRSA infections in the tertiary hospital setting was 51%. The aim of this study was to conduct a point prevalence survey of MRSA infections occurring at a tertiary-care hospital in Georgetown, Guyana, and to determine to what extent methicillin-resistance was occurring among Staphylococcus aureus isolates utilising the minimum inhibitory concentration (MIC) data. Study Design: This study was based on a prospective, analytical design. Place and Duration of Study: Microbiology department, Georgetown Public Hospital Corporation (GPHC), and Department of Medical Technology, University of Guyana, between May 2019 and July 2019. Methodology: A total of 101 consecutive, non-repetitive, laboratory-identified MRSA and methicillin-susceptible Staphylococcus aureus (MSSA) isolates were tested using an oxacillin broth microdilution method. Results: We found that 65.4% of Staphylococcus aureus were oxacillin (methicillin) resistant with a majority of the isolates being high level oxacillin resistant strains (i.e., MICs > 256 μg/ml) (84.85%). Most of the resistant isolates were collected from patients admitted to medical and surgical wards. Conclusion: Methicillin-resistance continues to be a major problem in the hospital setting and conventional techniques are unlikely to identify all of the potentially resistant isolates.


2010 ◽  
Vol 2 (02) ◽  
pp. 078-081 ◽  
Author(s):  
Shilpa Arora ◽  
Pushpa Devi ◽  
Usha Arora ◽  
Bimla Devi

ABSTRACT Aim: The emergence of Methicillin-resistant Staphylococcus aureus (MRSA) has posed a serious therapeutic challenge. We report the prevalence and antibiotic susceptibility pattern of MRSA in the hospitals attached to GMC, Amritsar, Punjab. Materials and Methods: The study comprised of 250 coagulase-positive staphylococci (COPS) isolated from a total of 6743 clinical specimens (like pus, blood, urine, high vaginal swab, sputum, etc.) of patients admitted in hospitals attached to Government Medical College, Amritsar from January 2008−February 2009. Routine antibiotic susceptibility testing was performed and interpreted as per standard guidelines. Methicillin resistance was detected using oxacillin and cefoxitin disc diffusion method, oxacillin screen agar method, and minimum inhibitory concentration using broth macrodilution method. Results: A total of 115 (46%) strains were found to be methicillin resistant. Multidrug resistance was observed in 73% MRSA strains. However, no strain was resistant to vancomycin. Conclusion: Regular surveillance of hospital-associated infection and monitoring of antibiotic sensitivity pattern is required to reduce MRSA prevalence.


2019 ◽  
Vol 26 (04) ◽  
Author(s):  
Aneela Khawaja ◽  
Faiqa Arshad ◽  
Rabiya Jamil

Introduction: The versatility of Staphylococcus aureus has been transformed as “Methicillin resistant Staphylococcus aureus”. The most challenging are the disastrous virulence patterns being expressed due to the selection pressure of antibiotics. For assessing the prevalence of methicillin resistant Staphylococcus aureus; screening by cefoxitin disc (30µg) diffusion method is still a realistic approach among conventional phenotypic methods, being applied in most of the laboratories. This reliable and feasible technique contributes significantly for MRSA detection. This study has been designed to evaluate the prevalence and identify the sensitivity pattern of methicillin resistant Staphylococcus aureus isolates from different clinical specimens in a tertiary care hospital. Study Design: Descriptive study. Setting: Pathology Department, Microbiology Laboratory, PGMI. Period: January 2015 to December 2015. Materials & Methods: A total 713 clinical isolates of Staphylococcus aureus were processed. Identification and confirmation of Staphylococcus aureus was done by colony morphology on blood agar, gram stain, catalase, coagulase and DNA-ase tests. Screening for methicillin resistance was done using cefoxitin disc (30mg, OXOID); while different antibiotic discs were used to assess the sensitivity profile by Modified Kirby-Bauer Disc Diffusion method according to CLSI guidelines (2016). Results: Out of 713 Staphylococcus aureus isolates, 92 (12.90%) isolates were labelled as methicillin resistant by cefoxitin disc diffusion test. Out of 92 MRSA isolates, 57 (14.65%) were recovered from male patients and 35 (10.80%) from female patients. While, 60 (65.22%) MRSA isolates showed hemolysis on blood agar. Among 92 MRSA isolates, 41 (44.57%) were recovered from pus specimen. Resistance to trimethoprim/sulfamethoxazole was highest (65.22%) after penicillin (100%); while all the MRSA isolates were 100% sensitive to both vancomycin and linezolid. Conclusion: The prevalence of MRSA in hospital care settings is of great clinical concern. To combat this public health threat effectively, continuous surveillance of health-care associated infections, along with local antibiotic sensitivity pattern of MRSA; as well as formulation of a definite antibiotic policy is required.


Author(s):  
Sonu S. Ahirwar ◽  
Prabhat Jatav ◽  
Kirti Kushwaha

Methicillin-resistant coagulase-negative staphylococci (MR-CoNS) associated infection is a growing concern in healthcare settings now a day. MR-CoNS are the main infectious agents of the hospital acquired infection. Clinical staffs to patients transmission of resistant strains have caused a rapid increase in the prevalence of antimicrobial resistance in recent years. Growing rate of antimicrobial resistant against available antibiotics of MR-CoNS is a developing problem in low income or lower middle income counties. This study was conducted to determine the occurrence MR-CoNS isolated from different clinical staffs of tertiary care hospital. This prospective study conducted in clinical staffs, nasal swab were collected from all the participants. Screening of CoNS were done on the basis of cultural, morphological and biochemical tests, identification and AST analysis done by VITEK-2 automated system. Methicillin resistance pattern was checked by VITEK-2 and Kirby-Bauer disc diffusion method according to CLSI guideline. A total of 129 nasal swab samples were collected from clinical staffs, of which n=81 isolates (85.6%) were CoNS. Among n=81 CoNS, (48.12%) , (41.97%) , (7.4%) and (2.4%) were reported. Out of n=81 CoNS isolates, n=26 were conformed as MR-CoNS. Maximum methicillin resistance were reported in 53.48% (14/26), 42.30% (11/26), 3.84% (1/26) and 0% (0/26). Theoccurrence rate of MR-CoNS are higher (20.6%) in the healthcare workers and most of the methicillin resistant-CoNS isolates shows high level of resistance against widely used antibiotics but all the isolates susceptible against vancomycin.


Author(s):  
Harsha Sreedharan ◽  
KB Asha Pai

Introduction: Methicillin-Resistant Staphylococcus aureus(MRSA) infection is a major global healthcare problem, the prevalence of which varies from 25-50% in India. It is known to cause Skin and Soft tissue Infections (SSI), endovascular infections, endocarditis, pneumonia, septic arthritis, osteomyelitis, and sepsis. Vancomycin is the drug of choice for treating severe MRSA infections. Ceftaroline, a fifth-generation cephalosporin has been approved by the United States Food and Drug Administration (US FDA) for treating acute bacterial SSI caused by susceptible micro-organisms including MRSA, Community acquired respiratory tract infection, MRSA bacteremia and endocarditis. Aim: To assess the susceptibility of clinical isolates of S. aureusto ceftaroline, in a Tertiary Care Hospital. Materials and Methods: This prospective study was conducted in the Department of Microbiology of a Tertiary Care Hospital over a period of two months from June 2019 to July 2019. S.aureus isolates from various clinical samples were screened for methicillin resistance by disc diffusion method using cefoxitin disc and ceftaroline susceptibility of these isolates was assessed by E-strip method. The isolates were classified as ceftaroline susceptible, Susceptibility Dose Dependent (SDD) and ceftaroline resistant respectively as per CLSI guidelines. A descriptive analysis of the data was done and the results were presented as frequencies and percentages. Results: All the S.aureus isolates were found to be susceptible to ceftaroline. Methicillin Sensitive Staphylococcus aureus(MSSA) isolates had lower Minimum Inhibitory Concentration (MIC) when compared to MRSA. The highest MIC among MRSA was 0.5 μg/mL. Conclusion: Ceftaroline can be considered as an effective alternative for treatment of infections caused by MRSA.


Author(s):  
Nilima R Patil

Background:- Methicillin resistant Staphylococcus aureus (MRSA) are responsible for hospital and community acquired infections. There are many laboratory methods for detection of MRSA. Chromogenic media have been used for the last few years for the quick detection of MRSA. Objective:- Aim of this study was to compare the performance of   conventional methods and chromogenic media for the detection of MRSA in a tertiary care hospital. Material and method: - 200 consecutive isolates of S. aureus confirmed by conventional methods, collected in a tertiary care hospital were used for this study. Cefoxitin and oxacillin disc diffusion test used as conventional methods and Chromogenic media i.e. oxacillin resistant screen agar base (ORSAB) was used for detection of methicillin resistant Staphylococcus aureus. All confirmed MRSA were checked by gold standard mecA base PCR method. Result: - Out of 200 isolates of Staphylococcus aureus, 50,52 and 47 strains were MRSA by Cefoxitin disc diffusion method, oxacillin disc diffusion method and oxacillin resistant screen agar base (ORSAB)  method respectively. Specificity was 100%, 98.66%, 98.66% by Cefoxitin disc diffusion, oxacillin disc diffusion and ORSAB method respectively. Conclusion: - In conclusion, cefoxitin disc diffusion was the best for the phenotypic detection of MRSA because their sensitivity and specificity were better than oxacillin and ORSAB.


2020 ◽  
pp. 1-2
Author(s):  
Asmita Singh ◽  
Anita Pandey ◽  
Amit Singh ◽  
Priyanka Chaturvedi

BACKGROUND: Staphylococcus aureus is a major human pathogen that causes wide range of clinical infections. Methicillin-resistant Staphylococcus aureus(MRSA) is endemic in India and is a dangerous pathogen causing hospital acquired infection leadings to signicant morbidity and mortality. OBJECTIVE:To study the prole of Staphylococcus aureusisolated from patients admitted in a tertiary care hospital. RESULT: Majority of clinical isolates of S.aurueswas obtained from patients of skin and soft tissue infection(54.66%) followed by those suffering from respiratory infection (13.33%), blood stream infection (13.33%) and UTI(8%). S.aureus was predominantly isolated from IPD samples, maximum cases were in the age group of 31-40 years and males outnumbered females. There was predominance of MRSA 112 (74.66%)which showed high level of resistance to penicillin (100%), ciprooxacin (82.14 %), co-trimoxazole (79.46%) and moxioxacin(85.71%). All the clinical isolates of S.aureuswere sensitive to linezolid andvancomycin (MIC <1ugm/ml). CONCLUSIONS: The clinical isolates of S.aureusshowed high level of resistance to various antimicrobial agents which is a signicant nosocomial threat. Surveillance and infection control practices should be carried out to prevent cross transmission of such resistant pathogen within the hospital setting


Author(s):  
Swati S. Kale ◽  
Ashwini Patil

Background: Staphylococcus aureus has emerged over the past several decades as a leading cause of hospital-associated and community acquired infections. Methicillin resistant S. aureus (MRSA), which are often resistant to several classes of antibiotics, is the most common cause of nosocomial infections and pose a great threat to the world. Vancomycin is regarded as the first-line drug for treatment of MRSA but resistance to this drug is being reported now a day.Methods: It was carried out for a period between January 2014 to June 2017 in the microbiology diagnostic laboratory. MRSA detection was performed by cefoxitin disk diffusion method. Screening for the vancomycin intermediate and the vancomycin resistant S. aureus (VISA and VRSA respectively) was carried out by using vancomycin screen. MIC (minimum inhibitory concentration) of vancomycin was tested by agar dilution method and E strip on all MRSA isolates.Results: A total of 287 S. aureus clinical isolates were included in the study. All MRSA were inoculated on vancomycin screen agar. Visible growth was present in 8 isolates. Five (3.73%) MRSA isolates with MIC of 4 were termed VISA (vancomycin intermediate S. aureus) by agar dilution method. Six isolates had the MIC of 4 and were termed as VISA.Conclusions: As disc diffusion method is not recommended by CLSI for S. aureus, vancomycin screen agar and MIC determination by either of the methods viz. agar dilution or E test can be used.


Author(s):  
Rohit Kumar ◽  
Jagarti . ◽  
Mrinmoy Sarma ◽  
Gautam Shalini

Background: The increasing frequency of MRSA infections and rapidly changing patterns in antimicrobial resistance, led to renewed interest in the usage of Macrolides-Lincosamide-Streptogramin B (MLSB) antibiotics to treat Staphylococcus aureus infection. Clindamycin is an important drug used in the treatment of MRSA and MSSA infection. The aim of this study was to determine inducible and constitutive clindamycin resistance among clinical isolates of Staphylococcus aureus by D-test.Methods: During a period of 6 months from July 2018 to December 2018, a total of 100 Staphylococcus aureus isolated from different clinical samples were subjected to routine antibiotic sensitivity testing by Kirby Bauer’s disc diffusion method. Methicillin-resistance was determined by using the cefoxitin (30 µg) disc. Incidence of MLSBc and MLSBi in Staphylococcus aureus isolates by D-test as per CLSI guidelines.Results: Out of 100 isolates of Staphylococcus aureus obtained from 350 clinical samples, 70(70%) were found to be MRSA and 30(30%) were MSSA. Among 100 Staphylococcus aureus isolates, 40% isolates showed MLSBi resistance, 28% isolates showed MLSBc resistance, 6% isolates showed MS phenotype and 26% isolates showed Sensitive phenotype. MLSBc and MLSBi were found to be higher in MRSA as compared to MSSA (21%, 27% and 7%, 10% respectively). All clinical isolates showed 100% sensitivity to Vancomycin and Linezolid in routine antibiotic susceptibility testing.Conclusions: Continuous surveillance of the MLSB resistance is important and required before the prescription of clindamycin to treat MRSA infections.


2018 ◽  
Vol 2 (1) ◽  

Aim: In today’s scenario, Nosocomial infection is a foremost problem in world. Methicillin resistant staphylococcus aureus (MRSA) strains are not only resistant to several antibiotics but also, show a particular ability to spread in hospitals of many countries. The main objective of the present study is to determine the prevalence of MRSA in surgical wound infections and also to define the antimicrobial susceptibility patterns of the strains isolated. Materials and Methods: A total of 133 culture positive Staph.aureus were taken from surgical site wound infections for the study during the period from March 2016 to February 2017. Routine Antibiotic Susceptibility testing was performed and interpreted as per latest CLSI guidelines. Methicillin resistance was detected using cefoxitin disc diffusion method. Results: In total of 133 samples, 81 (60.9%) were found to be MRSA. However, no strain was resistant to Vancomycin, Linezolid or Teichoplanin. Conclusion: Vigorous antimicrobial stewardship and strengthened infection control practices are mandatory to prevent spread and reduce emergence of resistance. Customary surveillance of hospital-associated infection and monitoring of antibiotic sensitivity pattern is required to reduce MRSA prevalence.


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