Browsing by Subject "Multidrug resistance"
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Item Antibiogram and Β-Lactamase Production Test of Multidrug Resistant Staphylococcus Species from Different Clinical Specimens(Department of Microbiology, 2012) Shrestha, ChandesworiThe aim of this study is to isolate the multidrug resistant (MDR) staphylococci from various clinical specimens and test the β-lactamase enzyme in multidrug resistant staphylococci by chromogenic cephalosporin sticks. Total of 205 were isolated and identified as Staphylococcus spp. using standard microbiological technique. The isolates were classified as S. aureus and CONS based on slide and tube coagulase test. The percentage of S. aureus and CONS isolates were 67% and 33% respectively. Thus identified 98 (47.8%) staphylococci were screened as multidrug resistant by employing Kirby-Bauer disc diffusion method as recommended by Clinical Laboratory Standard Institute (CLSI 2006). On sensitivity assay of S. aureus, vancomycin and nitrofurantoin were 95.6% and 100% sensitive respectively. S. aureus were highly resistant to ampicillin (74.5%), nalidixic acid (74.2%) and oxacillin (61.7%). CONS were also highly sensitive to vancomycin and nitrofurantoin with 97.1% and 100% respectively. CONS were highly resistant to oxacillin (66.7%), cloxacillin (62.5%) and nalidixic acid (56.8%). Of the total S. aureus and CONS isolates 48.9% and 45.5% were multidrug resistant. Prevalence of MDR was found higher in male (51.1%) and age group 70-79 (66.7%). About 46.4% of OPD isolates were MDR. The multidrug resistant staphylococci on nitrocefin stick test revealed that 47% were β-lactamase producers. Among them 46.3% and 51.6% were S. aureus and CONS respectively. β-lactamase producers were highly resistant to ampicillin, cephalexin and nalidixic acid each with 93.8% resistance. On a comparative study of cloxacillin disc of various manufacturing companies, cloxacillin disc from HI-MEDIA, S. aureus and CONS showed 96% and 97.13% resistance respectively. However, for OXOID and MAST showed equal resistance of 56.25% and 61.7% respectively. Staphylococci isolated were highly sensitive to Nitrofurantoin and Vancomycin. β-lactamase positive staphylococci were highly resistant toward multiple of antibiotics. This suggests the need for the β-lactamase test prior to the antibiotic prescription.Item Extended Spectrum Β-Lactamase and Metallo Β -Lactamase Producing Multidrug Resistant Gram Negative Bacteria among Patients with Renal Failure(Department of Microbiology, 2013) Pant, AnilPatients with renal failure are at greater risk of infection because of the abnormality in their immune system and the direct exposure of circulatory system to the microorganisms. The infection in such vulnerable population by drug resistant bacteria may lead to life-threatening consequences. The purpose of this study was to isolate and identify the multiple drug resistant Gram negative bacteria (MDRGNB) from kidney patients and hemodialysis patients and to screen those producing Extended-Spectrum β-Lactamases (ESBLs) and Metallo β-Lactamases (MBLs). During the study period (March-August, 2013), 496 samples of urine and 21 samples of blood collected from patients visiting and undergoing hemodialysis at National Kidney Centre (NKC) were processed. The isolates were identified by standard microbiological procdeures and subjected to antimicrobial susceptibility testing by modified Kirby Bauer disc diffusion methods. Production of ESBL and MBL was determined using MASTDISCSTM ID ESBL detection discs and imipenem EDTA combined disc assay respectively. The Minimum Inhibitory Concentration (MIC) of ciprofloxacin against the MDR isolates was also determined using agar dilution method. Total 103 (19.92%) samples showed significant growth and 85.43% of them were multidrug resistant. The higher rate of growth among female patients was found statistically significant (p<0.05). Imipenem was found to be most effective drug against the isolates whereas ceftazidime, with sensitivity and positive predictive value of 94.2% and 76.7% respectively was found to be more effective in screening ESBL producers among MDR strains than cefotaxime. Of the 59 MDR isolates suspected 35 (66.66%) were confirmed to produce ESBL with at least one Combined Disc (CD) assay used. Ceftazidime-clavulanate combined disc correctly identified all of the ESBL isolates whereas cefotaxime failed to confirm two isolates. Only one of the 11 isolates tested for MBL production was confirmed to produce MBL. The majority of ESBL isolates were Escherichia coli 29 (82.85%), whereas 2/2 (100%) of suspected Pseudomonas aeruginosa isolates were ESBL. None of the Proteus vulgaris were found to produce ESBL. Of note was the co-existence of ESBL and MBL in Pseudomonas aeruginosa. However, the production of MBL and resistance to carbapenems was statistically insignificant (p>0.05). The statistical pattern of resistance of ciprofloxacin, norfloxacin, ceftazidime and cefotaxime and ESBL production was found significant (p<0.05). Most of the isolates showed MIC value of 8µg/ml towards ciprofloxacin. Use of single screening agent for ESBL screening may result in false positive results, hence use of more than one of the screening agents and combined disk assay improves the sensitivity of detection of ESBL.Item Metallo ß-Lactamase Production and Antibiotic Suceptibility Pattern of Pseudomonas Aeruginosa Isolated from Clinical Samples(Department of Microbiology, 2013) Bagale, KamalPseudomonas aeruginosa is one of the leading causes of nosocomial infections.Carbapenems are used as the last resort for treatment of multidrug resistant(MDR)gram-negative bacterial infection. Resistance to this life saving drug has been increasingly reported in Pseudomonas which is mainly due to production of metallo β- lactamases. Therefore this present study was conducted with an objective to find the prevalence ofP. aeruginosa in different samples along with their antimicrobial susceptibility profile, find out the burden of MDR among P. aeruginosa and the production of metallo β-lactamases among those isolates. Total of5833samples were analysed, at the microbiology department of Shree Birendra Hospital’s, Chauni, Kathmandu from January 2013 to June2013, for routine culture and antibiotic susceptibility testing. Organisms were identified by conventional microbiological method and antibiotic susceptibility test was performed by Kirby-Bauer disc diffusion method. Metallo β-lactamases(MBLs)were detected by using combined disk test using imipenem with Ethylenediaminetetraacetic acid(EDTA).Out of 5833 samples analysed, 942showed positive growth among which 114 (12.1%) were Pseudomonas aeruginosa. Most of the isolates(95.6%)were sensitive to Imipenem and highest resistance (57.0%)was observed towards Ceftadizime. Only 33.3% of P. aeruginosa were multi drug resistant and most were isolated from ICU patients.Prevalence of metallo β- lactamases producing P. aeruginosa strains was 4.4% and all isolates were multi drug resistant.The study showed increasing trend of metallo β-lactamaseproducingisolates indicating the need of routine surveillance and timely control of the spread of these isolates in different units of health institutions. Key words: Pseudomonas aeruginosa, Multi drug Resistance, Metallo β-lactamaseItem Methicillin-Resistant staphylococcus Aureus (Mrsa) in Clinical Samples and Nasal Screening for Mrsa Carriage among Healthy carriers in Hospital Setting(Department of Microbiology, 2011) Thapa, Krishna BahadurStaphylococcus aureus is a Gram positive bacterium responsible for several bacterial infections. Antimicrobial resistance of S. aureusespecially methicillin-resistant S. aureus(MRSA), usually resistant to several antibiotics is a global public health problem,associated with considerable mortality and morbidity. This study investigated the susceptibility pattern of S.aureus isolates from various clinical samples and nasal swabsin the Shree Birendra hospital, Kathmandu. In addition, characterization of Methicillin-sensitive S. aureus(MSSA) and MRSA were reported to determine the current prevalence of MRSA as well as nasal carrier rate among hospital staffs and patient visitors. Characterization and identification of S. aureus was confirmed by microbiological methods and antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion method. A total of 138 S. aureuswere isolated from various clinical samples. Among isolates, 18.1% were found to be MRSA. Similarly 25.0% and18.0%S. aureus nasal carrier rate was found among health personnel and patient visitor srespectively. No MRSA was found among positive isolates from healthy carriers. The higher MRSA was isolated from inpatient setting. Among MSSA isolates from clinical samples, 60.2% (68/113) were multidrug-resistant (MDR) while among MRSA isolates,more than 90.0% were MDR. In case of nasal isolates from health personnel, only 32.0%(8/25) were MDR strains. Gentamicin was found to be more effective against MSSA with93.6% sensitivity. More than 50.0% of MRSA strains from clinical samples were resistant to all antibiotics used except Vancomycin. Isolates of both clinical samples and nasal swabs showed highest resistance towards penicillin. In view of the high resistancerates of MRSA to Gentamicin, Erythromycin, Ciprofloxacin and Cotrimoxazole,treatment of MRSA infections with these antibacterial agents would be unreliable.MRSA infections are still one of the most threatening infections in the hospitals. Therefore,regular surveillance of MRSA related infections including monitoring of antimicrobial susceptibility pattern of MRSA and formulation of a definite antimicrobial policy may behelpful for reducing MRSA prevalence in hospital setting. In addition, improvement of hygiene standards in hospitals among personnel and visitors will help to prevent S.aureus and MRSA transmission. Key words:S. aureus, MSSA, MRSA, nasal healthy carriers, MDR,Shree Birendra hospital