Study of antibiotics sensitivity pattern and molecular characterization of Staphylococcus aureus isolated from human and animal pyogenic cases.

Staphylococcus aureus has been described as the most common cause of human and animal diseases and has emerged as a superbug due to multidrug resistance. Considering these, a total of 175 samples were collected from pyogenic cases of humans (75) and animals (100), to establish the drug resistance pattern and also for molecular characterization of human and animal isolates. Thermonuclease (nuc) gene amplification was used to confirm all presumptive S. aureus isolates and then, antibiotic sensitivity and slide Coagulase tests were used for phenotypic characterization of isolates. Following that, all the isolates were subjected to PCR amplification to detect the existence of the Methicillin-resistant (mecA) and Coagulase (coa) genes. Lastly, typing was done using the Randomly Amplified Polymorphic DNA-PCR. The overall prevalence of S. aureus in human and animal samples was found to be 39.4%. Drug sensitivity revealed the highest resistance against the ß-lactam antibiotics such as ampicillin (94.8%) and penicillin (90.6%), followed by cephalosporin (cefixime-67.7%) and quinolone (ciprofloxacin-52.1%) group of drugs. The drug sensitivity was the highest against antibiotics like chloramphenicol (95%) followed by gentamicin (90%). Among the 69 S. aureus isolates, the overall presence of MRSA was 40.5% (27.5% and 50% in human and animal isolates, respectively). Total 33 isolates exhibited coa genes amplification of more than one amplicons and variable in size of 250, 450, 800, and 1100 bp. The RAPD typing revealed amplification of five and six different band patterns in humans and animals, respectively, with two common patterns suggesting a common phylogenetic profile.

Prevalence and antibiotyping of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in domestic animals in India.

OBJECTIVES: Domestic animals can serve as a reservoir for antimicrobial-resistant Staphylococcus aureus and may lead to the emergence of drug-resistant human isolates. The present study aimed to assess the prevalence and antibiotypes of S. aureus and methicillin-resistant S. aureus (MRSA) cultured from clinical pyogenic cases of domestic animals in India. METHODS: A total of 100 samples were collected during the study (August 2014 to July 2015) from different pyogenic conditions of cattle (n=21), buffaloes (n=63) and dogs (n=16). Samples were processed for isolation and phenotypic identification of S. aureus. Species identification was confirmed by PCR, and all of the isolates were screened for the mecA gene. Antimicrobial susceptibility testing was performed by the disk diffusion method for 14 antimicrobial agents. RESULTS AND CONCLUSION: The study revealed a 40.0% prevalence of S. aureus in pyogenic clinical cases of domestic animals. The species-wise prevalence of S. aureus was 38.1% both in cattle and buffaloes and 50.0% in dogs. The study revealed 21 antibiotypes among the S. aureus isolates. The rate of resistance was highest for amoxicillin (95.0%), followed by penicillin G (82.5%). Among the 40 S. aureus isolates, 23 (57.5%) exhibited methicillin resistance and carried the mecA gene. To the best of our knowledge based on the available literature, this is the first report of its kind from this country.

Rotational Dynamics in Ionic Liquids from NMR Relaxation Experiments and Simulations: Benzene and 1-Ethyl-3-Methylimidazolium.

Temperature-dependent (2)H longitudinal spin relaxation times (T1) of dilute benzene-d6 in 1-butyl-3-methylimidazolium tetrafluoroborate ([Im41][BF4]) and two deuterated variants of the 1-ethyl-3-methylimidazolium cation (Im21(+)-d1 and Im21(+)-d6) in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Im21][Tf2N]), measured at multiple Larmor frequencies, were used to probe rotational dynamics in ionic liquids. Rotational correlation times significantly faster than predicted by slip hydrodynamic calculations were observed for both solutes. Molecular dynamics simulations of these systems enabled extraction of more information about the rotational dynamics from the NMR data than rotation times alone. The multifrequency (2)H T1(T) data could be fit to within uncertainties over a broad region about the T1 minimum using models of the relevant rotational time correlation functions and their viscosity/temperature dependence derived from simulation. Such simulation-guided fitting provided confidence in the semiquantitative accuracy of the simulation models and enabled interpretation of NMR measurements to higher viscosities than previously possible. Simulations of the benzene system were therefore used to explore the nature of solute rotation in ionic liquids and how it might differ from rotation in conventional solvents. Whereas "spinning" about the C6 axis of benzene senses similarly weak solvent friction in both types of solvents, "tumbling" (rotations about in-plane axes) differs significantly in conventional solvents and ionic liquids. In the sluggish environment provided by ionic liquids, orientational caging and the presence of rare but influential large-amplitude (180°) jumps about in-plane axes lead to rotations being markedly nondiffusive, especially below room temperature.

How Is Diffusion of Neutral and Charged Tracers Related to the Structure and Dynamics of a Room-Temperature Ionic Liquid? Large Deviations from Stokes-Einstein Behavior Explained.

The deviations from Stokes-Einstein hydrodynamics of small solutes are more pronounced in ionic liquids than in conventional solvents (J. Phys. Chem. B 2013 117 (39), 11697). Small neutral solutes diffuse much faster than expected, whereas small charged solutes diffuse much slower. This article attempts to establish a link between the local friction experienced by tracer solutes and the polar/apolar structure of ionic liquids. We find that small neutral solutes probe locally "stiff" (mostly charged, high electrostriction) regions and locally "soft" (mostly apolar, low electrostriction) regions. These regions of high and low friction are associated with cage and jump regimes. Enhanced neutral tracer mobility in the low friction regions associated with the cationic apolar component has an important bearing on the large positive deviations from Stokes-Einstein behavior. In contrast, diminished charged tracer mobility involves long caging dynamics separated by jump events often triggered by the loss and recovery of counterions.

Development of a sandwich ELISA for the detection of bovine herpesvirus type 1.

OBJECTIVE: To develop a standard enzyme-linked immunosorbent assay (ELISA) for the detection of bovine herpesvirus type 1 (BHV-1). METHODS: The assay was based on hyperimmune rabbit and guinea pig antisera raised against purified BHV-1. Polyethylene glycol precipitation and sucrose density gradient methods were adopted for viral concentration and purification. Antisera were raised using Freund's adjuvant followed by extraction of IgG of high purity. RESULTS: Optimum antisera dilutions as determined by titrations were chosen as 1:4 000, whereas the conjugate was used at 1:2 000 dilution. Using 95 clinical specimens, the ELISA test showed a sensitivity and specificity of 91.90 % and 93.10 %, respectively when compared to PCR. The cut-off value was fixed at 0.15 (A(490)) and a P/N ratio of >1.30 indicated a significant positive reaction. CONCLUSIONS: The results have demonstrated that this ELISA could efficiently detect BHV-1 and can be used as an important diagnostic tool.