V Deotale

Inducible clindamycin resistance in Staphylococcus aureus isolated from clinical samples

PURPOSE Clindamycin is commonly used in the treatment of erythromycin resistant Staphylococcus aureus causing skin and soft tissue infections. In vitro routine tests for clindamycin susceptibility may fail to detect inducible clindamycin resistance due to erm genes resulting in treatment failure, thus necessitating the need to detect such resistance by a simple D test on routine basis. MATERIALS AND METHOD 247 Staphylococcus aureus isolates were subjected to routine antibiotic susceptibility testing including oxacillin (1ìg) by Kirby Bauer disc diffusion method. Inducible clindamycin resistance was detected by D test, as per CLSI guidelines on erythromycin resistant isolates. RESULTS 36 (14.5%) isolates showed inducible clindamycin resistance, nine (3.6%) showed constitutive resistance while remaining 35 (14.1%) showed MS phenotype. Inducible resistance and MS phenotype were found to be higher in MRSA as compared to MSSA (27.6%, 24.3% and 1.6%, 4% respectively). CONCLUSION Study showed that D test should be used as a mandatory method in routine disc diffusion testing to detect inducible clindamycin resistance.

STATUS OF HIGH LEVEL AMINOGLYCOSIDE RESISTANT ENTEROCOCCUS FAECIUM AND ENTEROCOCCUS FAECALIS IN A RURAL HOSPITAL OF CENTRAL INDIA

Considering the emergence of high level aminoglycoside resistance (HLAR) in enterococci this study was undertaken to determine their status in a rural setting. HLAR by disc diffusion and agar dilution, beta lactamase by nitrocefin disc and vancomycin resistance by agar dilution was determined in 150 enterococcal isolates, as per NCCLS guidelines. Only two species, Enterococcus faecalis (85.5%) and Enterococcus faecium (14.7%) were recovered, mostly from blood. Forty six percent showed HLAR. Multi drug resistance and concomitant resistance of HLAR strains to beta lactams were quite high. None showed beta lactamase activity or vancomycin resistance.

EVALUATION OF RAPID MTT TUBE METHOD FOR DETECTION OF DRUG SUSCEPTIBILITY OF MYCOBACTERIUM TUBERCULOSIS TO RIFAMPICIN AND ISONIAZID

PURPOSE To evaluate MTT method for detection of drug resistance to rifampicin and isoniazid in M.tuberculosis . This method utilises the ability of viable mycobacterial cells to reduce MTT( 3-4,5-dimethylthiazol-2-yl-2, 5-diphenyl tetrazolium bromide). METHODS The method was standardised with known resistant and sensitive strains of M.tuberculosis and was then extended to 50 clinical isolates. An inoculum of 10 7 cfu/mL was prepared in Middlebrook 7H9 medium supplemented with oleic acid, albumin, dextrose and catalase. For each drug three tubes were used, one with INH(0.2microg/mL) or RIF(1microg/mL), another as inoculum control and third as blank control. These were incubated at 37 degrees C for four and seven days respectively for RIF and INH after which MTT assay was performed. Results were read visually and by colorimeter at 570 nm. Relative optical density unit (RODU) of 0.2 was taken as cut off. Results were compared with drug sensitivity obtained by proportion method using LJ medium. RESULTS For rifampicin, concordance with proportion method was 90% by visual and 94% by RODU. Sensitivity and specificity was 86.8% and 100% respectively by visual method and 95.2% and 87.5% respectively by RODU. For Isoniazid, concordance was 94% and sensitivity and specificity was 94.7 and 91.7% respectively by both visual and RODU. CONCLUSIONS MTT assay proved to be rapid and cheap method for performing drug sensitivity of M.tuberculosis.

Changing patterns of Vibrio cholerae in Sevagram between 1990 and 2005

PURPOSE A retrospective analysis was done to note changes in prevalence, distribution of biotypes, serotypes, antibiotic susceptibility patterns and phage types of Vibrio cholerae isolated in Mahatma Gandhi Institute of Medical Sciences, Sevagram over a period of 16 years. METHODS A total of 535 strains of V. cholerae were isolated from 10,406 stool samples and rectal swabs from January 1990 to December 2005. These comprised of serogroups O1 - 427 (79.89%), O139 - 86 (16.07%) and non O1, non O139 - 22 (4.11%). No classical V. cholerae was isolated. RESULTS Vibrio cholerae serogroup O1 serotype Ogawa was the predominant isolate till 1992. During 1993, serogroup O139 became the main isolate; however, it completely disappeared during 1995-1996 only to reappear in 1997. Serotype Inaba in our area was conspicuous by its absence with only two strains being isolated till June 1999, but during July-December 1999, 11 out of 15 V. cholerae O1 isolates were El Tor Inaba. T4 was the predominant phage type till 1990, T2 during 1991-1994 and T27 (as per the new scheme) thereafter. Resistance to tetracycline varied between 2 and 17% for V. cholerae O1. CONCLUSIONS The paper reports on the changing epidemiological markers of V. cholerae isolated from a rural hospital over a period of 16 years.

Role of probiotics VSL#3 in prevention of suspected sepsis in low birthweight infants in India: a randomised controlled trial.

Objectives To assess the effect of the probiotic VSL#3 in prevention of neonatal sepsis in low birthweight (LBW) infants. Design Randomised, double-blind, placebo-controlled trial. Setting Community setting in rural India. Participants LBW infants aged 3–7 days. Interventions Infants were randomised to receive probiotic (VSL#3, 10 billion colony-forming units (cfu)) or placebo for 30 days, and were followed up for 2 months. Main outcome measure Possible serious bacterial infection (PSBI) as per the Integrated Management of Neonatal Childhood Illnesses algorithm, as diagnosed by fieldworkers/physicians. Results 668 infants were randomised to VSL#3 and 672 to placebo. By intention-to-treat analysis, the risk of PSBI among infants in the overall population of LBW infants was not statistically significant (RR 0.79 (95% CI 0.56 to 1.03)). Probiotics reduced median days of hospitalisation (6 days vs 3 days in probiotics) (p=0.018) but not the risk of hospitalisation (RR 0.66 (95% CI 0.42 to 1.04). The onset of PSBI in 10% of infants occurred on the 40th day in the probiotics arm versus the 25th day in the control arm (p=0.063). Conclusions Daily supplementation of LBW infants with probiotics VSL#3 (10 billion cfu) for 30 days led to a non-significant 21% reduction in risk of neonatal sepsis. A larger study with sufficient power and a more specific primary end point is warranted to confirm the preventive effect of VSL#3 on neonatal sepsis in LBW infants. Trial registration number The study is registered at the Clinical Trial Registry of India (CTRI/2008/091/000049).

Detection of metallo-β-lactamases producing Acinetobacter baumannii using microbiological assay, disc synergy test and PCR.

BACKGROUND One leading factor responsible for resistance in Acinetobacter baumannii, an important opportunist in health care institutions globally, is the production of carbapenamases like metallo-β-lactamases (MBLs), which hydrolyze a variety of β-lactams including penicillin, cephalosporins and carbapenems. However, neither any standard guidelines are available nor any method has been found to be perfect for their detection. Various methods have shown discordant results, depending upon the employed methodology, β-lactamase substrate and MBL inhibitor used. This study aims to evaluate two phenotypic methods against PCR as gold standard among carbapenem resistant A. baumannii for identifying MBL producers. MATERIALS AND METHODS A total of 130 A. baumannii were screened for imipenem and meropenem resistance by Kirby-Bauer disc diffusion method. Phenotypic expression of MBL was detected by EDTA-imipenem-microbiological (EIM) assay and extended EDTA disc synergy (eEDS) test and presence of bla-IMP and bla-VIM was detected by PCR in all the carbapenem resistant isolates. RESULTS Of the 43 imipenem and/or meropenem resistant A. baumannii isolates, 4 (9.3%) were found to be MBL producers by EIM and 3 (6.97%) by eEDS. Only bla-VIM gene was detected in 7 (16.28%) by PCR. In addition EIM detected 14 (32.56%) carbapenem resistant non-metallo enzyme producers. CONCLUSION Of the two MBL genes targeted, bla-VIM was only detected and that too in isolates resistant to both imipenem and meropenem. Further, EIM was useful in differentiating MBL from non-metalloenzymes producers.

Comparison of disc and MIC reduction methods with polymerase chain reaction for the detection of metallo-β-lactamase in Pseudomonas aeruginosa

PURPOSE The present study was undertaken to evaluate the screening antibiotic, confirmatory phenotypic test and agent against PCR as gold standard and to detect the prevalent MBL gene. MATERIALS AND METHODS Three hundred and twenty-six Pseudomonas aeruginosa isolates were screened for resistance to Imipenem (IPM), Meropemem (MEM) and Ceftazidime (CAZ) by disc diffusion. Isolates resistant to any of these were considered screen test-positive for MBL and were subjected to Double disc synergy test (DDST) and Disc potentiation test (DPT: Using IPM, MEM and CAZ alone and with EDTA), Minimum inhibitory concentration (MIC) reduction [four-fold or more reduction in MIC of IPM and MEM in presence of chelators: EDTA and 1,10-phenanthroline (EPI/EPM: EDTA-phenanthroline- Imipenem/Meropenem Broth Microdilution method)] and polymerase chain reaction (PCR) for blaIMP and blaVIM . RESULTS Screen test-positives by MEM and CAZ were 19.3% as against 17.8% by IPM. MEMDDST, DPT and EPM confirmed 100% screen-test positives as against 93.7% by CAZ DDST and DPT-2, 76.2% by CAZ DPT-1, 88.9% by IPM DDST, 85.7% by IPM DPT-1 and 92.1% by EPI. IPMand CAZ DDST together confirmed 100% while IPM and CAZ DPT-2 confirmed 96.8%. All 63 screen-test positives showed the presence of blaVIM . CONCLUSIONS MEM was found to be the best screening and confirmatory agent for MBL detection and blaVIM was found to be the prevalent MBL gene in this part of the country.

Spectrum of infections in acute febrile illness in central India

Introduction: Infectious agent when enters in the host results in febrile illness. This may lead to increase in morbidity or even mortality in undiagnosed/untreated cases. There are many aetiological agents which lead to acute febrile illness. Among these aetiological agents, important is bacterial or viral aetiology. Objective: The objective of this study is: (i) To know the aetiological agents responsible for acute undifferentiated febrile illness (AUFI) by serological test or by bacterial culture and (ii) To know the clinical profile of AUFI. Methodology: A total of 270 patients were enroled in the study with a history of AUFI admitted in medicine and paediatric department from January 2015 to November 2016 of tertiary care hospital of central India. Blood sample was collected for blood culture, clot culture and serological tests for immunochromatographic tests (ICTs) and ICT-positive results were confirmed by respective enzyme-linked immunosorbent assay (ELISA). All negative serum samples by immunochromatography were retested for disease-specific ELISA as scrub typhus, dengue and leptospirosis. Results: Out of 270 patients, 127 (47%) were of scrub typhus, 33 (12%) were malaria cases, 47 (17.40%) were dengue, 12 (4%) were enteric fever, 5 (2%) were leptospirosis, undiagnosed were 18 (6.66%) and other infections (viz viral, urinary tract infection, upper and lower respiratory tract infection and acute gastroenteritis) accounts for 28 (10.37%) cases. We have also noticed that there was co-infection of scrub typhus and dengue, leptospirosis and scrub typhus. Conclusion: It is important to know the cause and clinical profile of AUFIs for their proper management also it will help to prevent morbidity and mortality in AUFI cases.