Rapid and accurate detection of Methicillin Resistant Staphylococcus aureus (MRSA) is an important role of clinical microbiology laboratories to avoid treatment failure. The detection of MRSA is basedon phenotypic assays which require at least 24 h to perform. Detection of the mecA gene or of PBP 2a is the "gold standard", but not always available. The aim of this study was to evaluate a rapid method for detection of MRSA by using 3 (4, 5 dimethyl thiazole -2-yl) -2, 5 diphenyl tetrazolium bromide (MTT). Total 126 isolates of MRSA were collected from tertiary healthcare center and were confirmed by oxacillin screening agar test as per CLSI guidelines. Amplification of mecA gene was performed by using PCR. MTT assay was carried out for all the isolates in 96 well Microtitre plate and compared with standard methods of CLSI. Out of 126 isolates, 98 were found to be mecA positive. MTT method was found to be 98.98% sensitive and 96.43% specific. The MTT based colorimetric method is rapid and simple test for screening of oxacillin resistance in Staphylococcus aureus. It significantly shortens the time to just 7 h required to obtained a drug susceptibility test and could be useful to screen MRSA.Methicillin resistant Staphylococcus aureus (MRSA) strains emerged soon after the introduction of methicillin into clinical practice. MRSA is one of the major pathogen associated with serious nosocomial infection because this strain shows multiple drug resistance which limits treatment possibilities 1 . Numerous clinical studies have indicated, based on mortality rates, that MRSA strains are more virulent than methicillin-susceptible S. aureus (MSSA) strains 2 . The proportion of patients whose death is attributable to MRSA is significantly higher than that for MSSA 3 . Resistance to oxacillin is mostly mediated by the mecA gene, which codes for the production of a supplemental penicillin-binding protein, PBP2a or 2′, which is expressed either homogeneously or heterogeneously 4,5 . Expression of resistance in some MRSA strains is also regulated by homologues of the regulatory genes for blaZ that encodes for β -lactamase. These genes, mecI and mecR1, regulate the mecA response to β -lactam antibiotics in a fashion similar to that of the regulation of blaZ by the genes blaR1 and blaI upon exposure to penicillin 6 . Rosato et al. 7 have found that either mecI or blaI must be functional in all MRSA. An additional series of genes, the fem genes (factor essential for resistance to methicillin resistance), play a role in cross-linking peptidoglycan strands and also contributes to the heterogeneity of expression of methicillin resistance 8 . The typical heterogeneity seen in the expression of resistance to methicillin and in levels of resistance depends on the concerted action of chromosomally encoded genes, including fem and aux that are also present in the genome of susceptible staphylococci. Early detection of drug resistance is one of the essential steps in the management of MRSA infections and the effectiveness of a standard Anti-...

Background: Staphylococcus aureus is a leading cause of nosocomial and community acquired infection in every region of world. Clindamycin is a frequent therapeutic option in the treatment of skin and soft tissue infection caused by Staphylococcus aureus. However resistance to this drug is again a problem which may be inducible or constitutive. The present study was carried out to determine the prevalence of inducible clindamycin resistance among Staphylococcus aureus and to find out the relationship between methicillin resistant Staphylococcus aureus and inducible clindamycin resistance.Methods: A total of 177 Staphylococcus aureus isolated from different clinical samples were subjected to routine antibiotic sensitivity testing by Kirby Bauer disc diffusion method. All were tested for Methicillin resistance by using cefoxitin 30 µg disc. Inducible clindamycin resistance was detected by ‘D’ test as per CLSI guidelines.Results: Out of the 177 Staphylococcus aureus isolates, 77 (43.50%) were MRSA and 100 (56.50%) were MSSA. 101 (57.06%) isolates were erythromycin resistant. These erythromycin resistant isolates when subjected to ‘D’ test, 27 isolates showed MS phenotype, 26 showed inducible MLSB phenotype and 48 showed constitutive MLSB phenotype. Out of 77 MRSA isolates 23 (29.87%) showed Inducible MLSB phenotype and 33 (42.85%) showed Constitutive MLSB phenotype, while in 100 methicillin sensitive Staphylococcal isolates 03 (3%) showed Inducible MLSB phenotype and 15 (15%) showed Constitutive MLSB phenotype. The percentage of inducible and constitutive resistance was higher amongst MRSA isolates as compared to MSSA isolates.Conclusions: Study showed that ‘D’ test should be used routinely to detect inducible clindamycin resistance.

Introduction: Dengue is one of the most serious mosquito borne viral infection of man affecting mainly tropical and subtropical countries and caused by four serotypes of dengue virus, namely DEN-1, DEN-2, DEN-3 and DEN-4 belonging to genus flavivirus and family flaviviridae. It spreads through the bite of infected Aedes mosquito. Dengue is potentially fatal viral infection that can culminate into dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). The newer parameter NS1 antigen is detectable from day 1 of fever both in primary and secondary infections. Materials and Methods: Blood samples from clinically suspected cases of dengue tested immediately for qualitative detection of NS1 Ag, IgM and IgG antibodies by rapid solid phase immunochromatography test (ICT). Results: Out of 1090 samples tested, a total of 354 samples were tested positive for either one or more of the three markers i.e. NS1 Ag, IgM and IgG antibody tested. Of the 354 serum samples, 182 (51.41%) patients were positive for NS1 Ag only, 29 (8.19%) positive for IgM only, while 54 (15.25%) were positive for IgG only. More than one marker was detected in the remaining 89 (25.14%) samples. Primary dengue was detected in 224 (63.27%) cases and secondary dengue infection was detected in 130 (36.73%) cases. Conclusions: All suspected cases must be monitored for all three parameters i.e. NS1 Ag, IgM and IgG antibodies to differentiate between primary and secondary infection. Discrimination between primary and secondary dengue infections is important as the possibility of DHF and DSS is more in secondary infection.

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Background: Indian subcontinent is a hotspot of Typhoid activity with high prevalence rates. The Widal test is one of the commonly used sero-diagnostic test for typhoid fever in developing countries. Lack of proper knowledge of baseline titre of Widal test can lead to over diagnosis of typhoid fever leading to mismanagement of patients. A single cut off value on average titre among healthy individuals needs to be determined. So, the purpose of the present study was to develop recommendations for the interpretation of Widal test results in the local region. The objectives were to determine the baseline Widal titre of study population and to propose titre-values of significance in the diagnosis of enteric fever.Methods: Sera of 242 apparently healthy blood donors from January 2016 to December 2016 in blood bank and Department of Microbiology, Dr. PDMMC, Amravati, Maharashtra, India were subjected to standard quantitative tube and semi-quantitative slide Widal test to know the titre.Results: Highest titre obtained by tube Widal test for TO was 1:320, for TH- 1:160, for AH- 1:80, and for BH- 1:80. Tube Widal titres of ≤1:160 for TO were seen in 238 (98.34%) and for TH titre of ≤1:80 were seen in 238 (98.34%), TO and TH titres of ≥1:160 were seen in 24 (9.91%) and 4 (1.65%) respectively. TO titre of 1:320 was seen in 4(1.65%) and TH titre of 1:160 was seen in 4 (1.64%). Highest titre obtained by semi-quantitative slide Widal for TO was 1:640, for TH, AH and BH was 1:160.Conclusions: We recommend that TO titre of ≥1:320 and TH titre ≥1:160 as diagnostic of typhoid fever and for AH and BH, titres of ≥1:80 should be considered diagnostic respectively in our region. Because of high expected false positivity rate of slide Widal test.