Purpose: The purpose of this study was to evaluate three methods for detection of biofilm formation in staphylococci. Methods: For detection of biofilm formation, 152 clinical isolates of Staphylococcus spp. were screened by tissue culture plate (TCP), Tube method (TM) and Congo red agar (CRA) method. Results: Of the 152 Staphylococcus spp. 88(57.8%) displayed a biofilm-positive phenotype under the optimized conditions in the TCP method and strains were further classified as high 22 (14.47 %) and moderate 60 (39.4 %) while in 70 (46.0 %) isolates weak or no biofilm was detected. Though TM correlated well with the TCP test for 18 (11.8 %) strongly biofilm producing strains, weak producers were difficult to discriminate from biofilm negative isolates. Screening on CRA does not correlate well with either of the two methods for detecting biofilm formation in staphylococci. Conclusion: The TCP method was found to be most sensitive, accurate and reproducible screening method for detection of biofilm formation by staphylococci and has the advantage of being a quantitative model to study the adherence of staphylococci on biomedical devices. Key words: Staphylococci, adherence, biofilm, tissue culture plate, Congo red agarStaphylococci are most often associated with chronic difficult to eradicate and are often resistant to systemic infections of implanted medical devices.1-3 The use of antibiotic therapy and removal of infected device becomes indwelling medical devices is important in the treatment of necessary.9-11 The differentiation of staphylococci with respect critically and chronically ill patients, however bacterial to its biofilm phenotype might help to elucidate the impact colonization of implanted foreign material can cause major of staphylococci in diagnosis of infections related to medical and economic sequel. The increased use of indwelling biomedical devices and these observations may have utility medical devices has had considerable impact on the role of in the prevention of device related infections. 12 staphylococci in clinical medicine. The predominant species isolated in these infections are Staphylococcus epidermidis A number of tests are available to detect slime production and Staphylococcus aureus,their major pathogenic factor being by staphylococci; methods include tissue culture plate (TCP), ability to form biofilm on polymeric surfaces. 4 Biofilm 13 tube method (TM), 14 Congo red agar (CRA), 15,17 consists of multilayered cell clusters embedded in a matrix bioluminescent assay 18 and light or fluorescence microscopic of extracellular polysaccharide (slime), which facilitates the examination. 19,20 These methods are often subject to severe adherence of these microorganisms to biomedical surfaces and analytical limitations and are unable to detect bacterial protect them from host immune system and antimicrobial adherence accurately. In this study, we simultaneously therapy.5 screened 152 clinical isolates of Staphylococcus spp. by TCP (standard and modified), TM and CRA methods for Biofil...

BackgroundDengue, a mosquito-borne viral disease, poses a significant global public health risk. In tropical countries such as India where periodic dengue outbreaks can be correlated to the high prevalence of the mosquito vector, circulation of all four dengue viruses (DENVs) and the high population density, a drug for dengue is being increasingly recognized as an unmet public health need.Methodology/Principal findingsUsing the knowledge of traditional Indian medicine, Ayurveda, we developed a systematic bioassay-guided screening approach to explore the indigenous herbal bio-resource to identify plants with pan-DENV inhibitory activity. Our results show that the alcoholic extract of Cissampelos pariera Linn (Cipa extract) was a potent inhibitor of all four DENVs in cell-based assays, assessed in terms of viral NS1 antigen secretion using ELISA, as well as viral replication, based on plaque assays. Virus yield reduction assays showed that Cipa extract could decrease viral titers by an order of magnitude. The extract conferred statistically significant protection against DENV infection using the AG129 mouse model. A preliminary evaluation of the clinical relevance of Cipa extract showed that it had no adverse effects on platelet counts and RBC viability. In addition to inherent antipyretic activity in Wistar rats, it possessed the ability to down-regulate the production of TNF-α, a cytokine implicated in severe dengue disease. Importantly, it showed no evidence of toxicity in Wistar rats, when administered at doses as high as 2g/Kg body weight for up to 1 week.Conclusions/SignificanceOur findings above, taken in the context of the human safety of Cipa, based on its use in Indian traditional medicine, warrant further work to explore Cipa as a source for the development of an inexpensive herbal formulation for dengue therapy. This may be of practical relevance to a dengue-endemic resource-poor country such as India.

The purpose of this study was to simultaneously screen for Extended-spectrum β-lactamases (ESBL) and AmpC β-lactamases in gram negative clinical isolates from four tertiary care hospitals and further to compare two detection methods three-dimensional extraction method and AmpC disk test for AmpC β-lactamases. A total of 272 isolates were screened for ESBL and AmpC ß-lactamase by modified double disk approximation method (MDDM). Synergy observed between disks of ceftazidime/cefotaxime and clavulanate were considered as ESBL producer. Isolates showing reduced susceptibility to either of the test drugs (ceftazidime or cefotaxime) and cefoxitin were considered as presumptive AmpC producers and further confirmed by three-dimensional extraction method and AmpC disk test. A total of 173 (64%) of the isolates were found to be ESBL positive and 61 (23%) showed resistant to cefoxitin. ESBL was detected in 80 (62%) isolates of E. coli and 71 (73%) of Klebsiella spp. The occurrence of AmpC β-lactamases was found to be 8% (22) of the total isolates and the two detection methods for AmpC β -lactamase showed concordant results. Screening for ESBL and AmpC can be simultaneously done by MDDM method and confirmation for AmpC ß-lactamase should be carried out routinely in tertiary care hospitals by AmpC disk test, as it is a simple and rapid procedure.

Decreased susceptibility of Neisseria meningitidis isolates to ciprofloxacin emerged from an outbreak in Delhi, India. Results of antimicrobial susceptibility testing of the meningococcal isolates to ciprofloxacin and further sequencing of DNA gyrase A quinolone-resistance–determining region confirmed the emergence of ciprofloxacin resistance in the outbreak.

Oxazolidinones are known to inhibit protein biosynthesis and act against a wide spectrum of gram-positive bacteria. A new investigational oxazolidinone, ranbezolid, inhibited bacterial protein synthesis in Staphylococcus aureus and Staphylococcus epidermidis. In S. epidermidis, ranbezolid showed inhibition of cell wall and lipid synthesis and a dose-dependent effect on membrane integrity. A kill-kinetics study showed that ranbezolid was bactericidal against S. epidermidis. In vitro translation of the luciferase gene done using bacterial and mammalian ribosomes indicated that ranbezolid specifically inhibited the bacterial ribosome. Molecular modeling studies revealed that both linezolid and ranbezolid fit in similar manners the active site of ribosomes, with total scores, i.e., theoretical binding affinities after consensus, of 5.2 and 6.9, respectively. The nitrofuran ring in ranbezolid is extended toward C2507, G2583, and U2584, and the nitro group forms a hydrogen bond from the base of G2583. The interaction of ranbezolid with the bacterial ribosomes clearly helps to elucidate its potent activity against the target pathogen.