scholarly journals The study of reduced susceptibility of methicillin resistant Staphylococcus aureus to various antibiotics with special reference to glycopeptides in a tertiary care hospital in central India

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.

2015 ◽  
Vol 13 (2) ◽  
pp. 35-38
Author(s):  
Sabita Bhatta ◽  
Babli Basu ◽  
Chandrasekhar Narharrao Chaudhary ◽  
Ashok Kumar Praharaj

Introduction: Tigecycline is a novel glycylcycline  derivative of the tetracycline with activity against a wide range of  organisms including Methicillin resistant Staphylococcus aureus, Vancomycin  resistant  Enterococcus , Extended spectrum beta lactamase   producing  (Escherichia coli , Klebsiella  pneumonia)  and Acinetobacter species.  The aim of the study was to assess effectiveness of the drug against methicillin resistant Staphylococcus aureus (MRSA), vancomycin resistant enterococci (VRE), ESBL producers and carbapenem resistant Acinetobacter baumannii and to compare the efficacy of different methods of antimicrobial susceptibility testing for Tigecycline.Methods: A total of 250 clinical isolates were processed and identified by conventional methods. In all the 250 isolates, antimicrobial susceptibility was carried out by disc diffusion method , Minimum inhibitory test by agar dilution method (MIC) and in 30 isolates of A baumannii  MIC was also done by E test.Results: Out of 250 isolates, 236 isolates were sensitive to tigecycline by agar dilution method while only 159 were sensitive by disk diffusion method.Conclusion: Marked discordance was observed between the results of two different methods (DDT & Agar dilution method) for E coli, Klebsiella spp and A baumannii, where significant number of isolates were resistant to tigecycline by DDT as compared to AD method. But results of MIC by agar dilution method & E test were in concordance for A. baumannii.


2016 ◽  
Vol 41 (2) ◽  
pp. 101-107 ◽  
Author(s):  
Nazma Khatun ◽  
Refath Farzana ◽  
Bruno S. Lopes ◽  
S.M. Shamsuzzaman

This study was designed to investigate the resistance profile along with the genetic background of resistance to beta-lactam antibiotics among the nosocomial A. baumannii in Bangladesh. A. baumannii was confirmed by detecting blaOXA-51-like. Antibiotic susceptibility was determined by disk diffusion method. Agar dilution method was used to determine MIC of ceftazidime and imipenem. All A. baumannii were phenotypically screened for ampC, ESBL and MBL production. Genetic markers of antibiotic resistance such as blaampC, blaOXA-51, 23, 40, 58 and 143, blaKPC, blaIMP, blaVIM and blaNDM-1, genetic environment around blaADC and ISAba1 upstream of blaOXAs were evaluated by PCR. Twenty-four (96%) A. baumannii were considered as MDR. 96% A. baumannii were resistant to amoxiclav, ceftazidime, ciprofloxacin and cefoxitin, 92% to cefotaxime and piperacillin-tazobactam, 88% to cefepime, amikacin and imipenem, 52% to sulbactam-cefoperazone and 40% were resistant to aztreonam. All were sensitive to colistin. The distribution of several beta-lactamase genes such as blaOXA-51 (100%), blaADC-like (92%), blaNDM-1 (92%), EBC group (84%), blaOXA-23 (76%), blaVIM (72%), blaKPC (44%), DHA group (24%), blaOXA-58 (16%), ACC group (8%) and CIT group (4%) were observed among the 25 A. baumannii. This is the first reported plasmid mediated ampC beta-lactamases in A. baumannii. blaOXA-51 was positive in 100%, blaNDM-1 in 95.45%, blaOXA-23 in 77.27%, blaVIM in 72.73%, blaKPC in 50% and blaOXA-58 in 18.18% of imipenem resistant isolates. MDR profile of nosocomial A. baumannii would highlight the importance of standard guideline of antimicrobials use and infection control policy in the hospitals of Bangladesh.


2008 ◽  
Vol 52 (No. 4) ◽  
pp. 169-174
Author(s):  
M. Holasova ◽  
R. Karpiskova ◽  
S. Karpiskova ◽  
V. Babak ◽  
J. Schlegelova

With a microdilution method, using the commercial diagnostic test Sensititre Susceptibility Plates for Campylobacter MIC (Trek Diagnostic Systems, Cleveland, OH, USA), disk diffusion and agar dilution method, resistance to six antimicrobial agents were examined in a reference strain <i>Campylobacter jejuni</i> ATCC 33560 and 73 thermo-tolerant isolates of <i>Campylobacter</i> spp. For the microdilution method and all tested antimicrobial agents, our determined values of microbiological breakpoints of resistant strains were suggested as the minimum inhibitory concentration (MIC<sub>R</sub>) for ciprofloxacin &ge; 0.5, erythromycin &ge; 4, gentamicin &ge; 4, nalidixic acid &ge; 32 and tetracycline &ge; 4 &mu;g/ml. On the basis of our study results, strains resistant to clindamycin were MIC<sub>R</sub> &ge; 2 &mu;g/ml for the dilution methods and a zone diameter R ≤ 16 mm for the disk diffusion method. Comparison of the results of the resistance examination, a microdilution method and disk diffusion method with the reference agar dilution method, showed that all compared methods yielded identical results with the exception of the resistance determination in erythromycin and nalidixic acid. The errors were mostly the result of the interpretation criteria for MIC<sub>R</sub> of agar dilution method and different conditions of cultivation used. However, the compared methods, provide results comparable with the reference method having greater convenience of measurement.


2011 ◽  
Vol 50 (1) ◽  
pp. 52-56 ◽  
Author(s):  
Mirva Lehtopolku ◽  
Pirkko Kotilainen ◽  
Pauli Puukka ◽  
Ulla-Maija Nakari ◽  
Anja Siitonen ◽  
...  

2017 ◽  
Vol 3 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Shahana Khanam ◽  
Jalaluddin Ashraful Haq ◽  
SM Shamsuzzaman ◽  
Md Motlabur Rahman ◽  
Kazi Zulfiquer Mamun

Background: Glycopeptides such as vancomycin are frequently the choice of antibiotics for the treatment of infections caused by methicillin resistant Staphylococcus aureus (MRSA). For the last 7 years incidence of vancomycin intermediate S. aureus and vancomycin resistant S. aureus (VISA and VRSA respectively) has been increasing in various parts of the world.Objective: The present study was carried out to find out the presence of VISA and VRSA among isolated MRSA strains.Methodology: This cross sectional study was carried out in the Department of Microbiology in Dhaka medical college during period of January 2010 to December 2011. All S. aureus isolates were screened to detect methicillin resistance and then all MRSA isolates were subjected for MIC testing against vancomycin and oxacillin by agar dilution method, disc diffusion testing and PCR for mecA and pvl genes detection.Result: A total 112 S. aureus were isolated from 500 nasal swab sample collected from adult patients who were admitted in various departments and wards in Dhaka Medical College Hospital. Among 38 MRSA strains out of 112 Staph aureus isolates 3(7.89%) strains were resistance to vancomycin of which 2(5.26%) strains had MIC > 256 mg/mL and one strain had MIC 256mg/mL. All vancomycin resistance strains had MIC of oxacillin > 256 mg/mL. All isolates possess mec-A gene.Conclusion: The present study reveals that emergence of VRSA upon admission at a tertiary care of hospital in Bangladesh. Continuous efforts should be made to prevent the spread and the emergence of VRSA by early detection of the resistant strains and using the proper infection control measures in the hospital setting.Bangladesh Journal of Infectious Diseases 2016;3(1):11-16


2016 ◽  
Vol 8 (01) ◽  
pp. 050-054 ◽  
Author(s):  
Varun Goel ◽  
Dinesh Kumar ◽  
Rajendra Kumar ◽  
Purva Mathur ◽  
Sarman Singh

ABSTRACT Background: Urinary tract infections (UTIs) remain a major problem both in hospitalized and outdoor patients. Multidrug-resistant enterococci are emerging as a major nosocomial pathogen with increasing frequency. However, the incidence of community-acquired enterococcal infections and species prevalent in India is not thoroughly investigated. Objectives: This study aims to estimate the burden of community-acquired UTIs seen at a tertiary care hospital and to identify the Enterococcus species isolated from these patients. The study also aims to determine the antibiotic susceptibility pattern with reference to high-level aminoglycosides and vancomycin. Materials and Methods: Semi-quantitative cultures from a total of 22,810 urine samples obtained from patients seen at various Outpatient Departments were analyzed. From them 115 nonduplicate isolates of enterococci were obtained as significant pure growth (>105 cfu/ml) and speciated. Antibiotic susceptibility was performed by Kirby–Bauer disc diffusion method. Vancomycin resistance screening was performed by the vancomycin screen agar method recommended by Clinical and Laboratory Standards Institute and confirmed by determination of minimum inhibitory concentration by agar dilution method. Results: Of 115 enterococcal isolates, 61 were identified as Enterococcus faecalis, 42 as Enterococcus faecium, 3 each as Enterococcus dispar, and Enterococcus pseudoavium. High-level gentamicin resistance (HLGR) was higher in E. faecium (47.6%) than E. faecalis (32.7%) and HLSR also showed the same pattern with 47.6% and 27.9% resistance, respectively. Vancomycin resistant enterococci accounted for 11.3% of the isolates, and out of them 53.8% were E. faecium by agar dilution method. Conclusion: High rate of resistance to antibiotics of penicillin group and aminoglycosides was observed in our tertiary care hospital even in community acquired UTIs. Hence, there is an urgent need for more rational and restricted use of antimicrobials.


Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2060
Author(s):  
Sayara Bista ◽  
Upendra Thapa Shrestha ◽  
Binod Dhungel ◽  
Pragya Koirala ◽  
Tulsi Ram Gompo ◽  
...  

Background: Plasmid-mediated resistance to the colistin in poultry is considered as an emerging problem worldwide. While poultry constitutes the major industry in Nepal, there is a paucity of evidence on colistin resistance in Escherichia coli isolates causing natural infections in poultry. This study aimed to explore the prevalence of plasmid-mediated colistin resistance gene, mcr-1 in E. coli isolated from liver samples of dead poultry suspected of E. coli infections. Methods: A total of two hundred and seventy liver samples (227 broilers and 43 layers) from dead poultry suspected of colibacillosis were collected from post-mortem in the Central Veterinary Laboratory (CVL), Kathmandu, between 1 February and 31 July 2019. The specimens were processed to isolate and identify E. coli; an antimicrobial susceptibility test (AST) using disk diffusion method was performed with 12 different antibiotics: Amikacin (30 µg), ampicillin (10 µg), ciprofloxacin (5 µg), chloramphenicol (30 µg), cefoxitin (30 µg), ceftazidime (30 µg), ceftriaxone (30 µg), cotrimoxazole (25 µg), gentamicin (10 µg), imipenem (10 µg), levofloxacin (5 µg) and tetracycline (30 µg). Colistin resistance was determined by agar dilution method and colistin-resistant strains were further screened for plasmid-mediated mcr-1 gene, using conventional polymerase chain reaction (PCR). Results: Out of 270 liver samples, 53.3% (144/270) showed growth of E. coli. The highest number (54%; 109/202) of E. coli isolates was obtained in the liver samples from poultry birds (of both types) aged less than forty days. In AST, 95.1% (137/144) and 82.6% (119/144) of E. coli isolates were resistant against tetracycline and ciprofloxacin, respectively, while 13.2% (19/144) and 25.7% (37/144) isolates were resistant to cefoxitin and imipenem, respectively. In the same assay, 76.4% (110/144) E. coli isolates were multi-drug resistant (MDR). The phenotypic prevalence of colistin resistance was 28.5% (41/144). In the PCR assay, 43.9% (18/41) of colistin-resistant isolates were screened positive for plasmid-mediated mcr-1. Conclusion: The high prevalence of mcr-1 in colistin-resistant E. coli isolates in our study is a cause of concern for the probable coming emergence of colistin resistance in human pathogens, due to horizontal transfer of resistant genes from poultry to human 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.


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.


2011 ◽  
Vol 6 (04) ◽  
pp. 317-323 ◽  
Author(s):  
Ezekiel Olugbenga Akinkunmi ◽  
Adebayo Lamikanra

Introduction: The study aimed to investigate the resistance of methicillin resistant Staphylococcus aureus (MRSA), an indicator used in hospitals but isolated from faecal samples of children in the community, to commonly used antibiotics and antiseptic agents. Methodology: S. aureus isolates were identified by phenotypic and genotypic techniques such as biochemical tests and polymerase chain reaction. Antibiotic susceptibility was investigated using the disc diffusion technique while the agar dilution method was used to determine the minimum inhibitory concentration (MIC) of antiseptics. Results: MRSA showed considerably higher resistance to other antibiotics than methicillin sensitive Staphylococcus aureus (MSSA). Twelve percent of the MSSA were susceptible to all the antibiotics studied while none of the MRSA had this property. A significant difference in susceptibility between MRSA and MSSA to the three antiseptic agents was observed as 68.8%, 75.0% and 100% of MRSA were less susceptible to benzalkonium chloride, chlorhexidine and cetrimide respectively, while 32.0%, 28.0% and 56.0% of MSSA respectively were less susceptible to these agents compared with S. aureus NCTC 6571. Overall, the MICs for the antiseptics were 2-3 times greater in the MRSA than in the MSSA (p < 0.001). Conclusion: Results show that the concentration of antiseptics used in the prevention of the transmission of infectious agents may have to be raised to cope with the possible presence of MRSA in patients coming into hospital.


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