Multidrug-resistant Enterobacteriaceae including metallo-β-lactamase producers are predominant pathogens of healthcare-associated infections in an Indian teaching hospital.

Purpose: A study was carried out in an Indian teaching hospital in 2009 to detect the rate of surgical site infections (SSI) and peripheral vascular access site infections. Materials and Methods: The study was a point-prevalence study involving over 300 patients. The presence of infection was determined according to the CDC criteria. Swabs were taken from the infected sites and identification and sensitivity were carried out using VITEK® 2 automated system. Characterisation of β-lactamase was carried out at ARRML, Colindale, London. Results: The rate of SSI was 15% for the clean and clean-contaminated categories while that for the dirty contaminated category was 85% (NNIS risk index 0). Cultures yielded definite or probable pathogens from 64% (9/14) of the patients with SSI. In 1/3 rd of the cultures, Staphylococcus aureus was grown and the rest had Enterobacteriaceae, either extended-spectrum β-lactamase (ESBL) producers or Amp-C hyperproducers and, alarmingly, three isolates were positive for newly recognised New Delhi metallo-β-lactamase-1 (NDM-1). In medicine, 87% (n = 99) of the patients had a peripheral IV access device, 55% developed associated phlebitis/infection and, in seven, probable pathogens were isolated (Candida species and Escherichia coli producing ESBL and NDM-1, respectively, Staphylococcus aureus and Enterococcus faecium). All ESBL and metallo-β-lactamase producers were resistant to multiple classes of antimicrobials, the latter being sensitive only to colistin and tigecycline. The study also found that all post-operative patients were on antibiotics, 92% on IV [213 defined daily doses (DDD)/100 post-op patients] limited mainly to the third-generation cephalosporins (26%) and aminoglycosides (24%) and imidazole derivatives (30%). In medicine, 83% (n = 82) were on IV antibiotics (123 DDD/100 bed-days), limited mainly to the third-generation cephalosporins (74%). Conclusion: Indiscriminate use of antibiotics is a major problem predisposing patients to harm by multi-resistant pathogens. Carbapenems were in little use in this hospital, but the selection pressure exerted by cephalosporins and other unrelated classes was sufficient to select NDM-1-producing strains due to co-selection, suggesting a role of single plasmid carrying resistance genes to multiple classes.

Biological microemulsions V: mutual mixing of oils, amphiphiles and water in ternary and quaternary combinations.

The mixing behaviour of plant oils (ricebran, saffola and clove) with water in presence of amphiphiles (Triton X-100, Tween-60, Aerosol OT, Igepal, Na-oleate, ethanol and cinnamic alcohol) in various ternary and quaternary combinations has been studied. The phase behaviour at different mass proportions and temperature has been investigated in the absence and presence of additives such as NaCl, glucose, urea and cholesterol. Of all the combinations studied, those with ethanol plus sodium oleate as amphiphile have shown maximum extent of single phase microemulsion formation. The presence of urea in the aqueous medium has further increased the monophasic extent whereas NaCl has decreased it. Cholesterol in oil and glucose in water have apparently shown inert effects. The effects of the additives on the formation of biphasic or triphasic formulations, on the other hand, have been found to be distinct and well-dependent on [H2O]/[amphiphile] mole ratio and temperature. Spectral measurements of I3- in the aqueous micropool in microemulsion of clove oil/(ethanol + Na-oleate)/water have shown the microenvironment to be physicochemically different from bulk water.

Biological microemulsions: Part IV--Phase behaviour and dynamics of microemulsions prepared with vegetable oils mixed with aerosol-OT, cinnamic alcohol and water.

Microemulsification of vegetable oils (ricebran, saffola, soyabean, sesame, palm and linseed) with water using aerosol-OT and cinnamic alcohol as mixed amphiphiles was studied. The biological microemulsions formed covered on the average approximately 27% of single phase area in the triangular phase diagram. The multiphasic zone for saffola was studied in detail, two- and three-phase zones were identified with patches of thick gel. The effect of temperature on the multiphase formation in the range 29-55 degrees C was also studied. The formation of multiphase and their proportions found to depend on the type of oil. The biological microemulsions at reasonable water/AOT mole ratio showed moderate increase in conductance with temperature. The viscosity of the microemulsions was high. Of the studied systems (sesame, saffola and ricebran) the viscosity of the first two decreased with the rate of shear whereas that of ricebran increased. When cinnamic alcohol was used as the oil, the trend of viscosity was similar to that of sesame and saffola.

Perinatal mortality in caesarean section: a disturbing picture of unfulfilled expectations.

Indications for caesarean section had been studied in a 2-year period and the incidences were compared to that of the same 15 years back. Though there are more incidences of caesarean section, still perinatal death is a major concern to all. The study included a total of 291 perinatal deaths of which there were 208 early neonatal deaths and 83 stillbirths over a period of 2 years from January, 1990 to December, 1991. Caesarean section is being increasingly performed for foetal interest, but this study reveals that perinatal mortality is still high though cesarean section rate has increased in recent times.

Thermodynamics of water-induced precipitation of cholesterol and its acetate, benzoate and stearate derivatives dissolved in 1,4-dioxane and 2-propanol.

The energetics of the precipitation process depended on the solute-solvent combination and the enthalpy and entropy of precipitation compensated each other. The partial molal volumes of the lipids in both the solvents were greater than the anhydrous molar volumes, except for cholesterol in 1,4-dioxane and cholesteryl acetate in 2-propanol where the order was reverse. While the partial molal compressibilities of all the solutes studied were negative in 1,4-dioxane, those of cholesterol and cholesteryl acetate in 2-propanol were, respectively, negative and positive. The negative values were supported by considerable solvation of the solutes, particularly in 1,4-dioxane.

Water-induced precipitation of cholesterol dissolved in organic solvents in the absence and presence of surfactants and salts.

The precipitation of cholesterol dissolved in organic solvents, viz. methanol, ethanol, n-propanol, isopropanol, acetone and 1,4-dioxane, by the addition of water has been studied. The effects of the solvents towards the precipitation follow the order: methanol greater than ethanol greater than acetone greater than dioxane greater than n-propanol greater than iso-propanol, the solvent dioxane however exhibits a change in the order at higher concentration. Additives like Triton X-100, sodium cholate, sodium deoxycholate, sodium dehydro cholate, sodium salicylate and sodium chloride have some protective action against precipitation, the maximum protection being that of Triton X-100. The additives have shown better protective action in propanols and dioxane than in methanol, ethanol and acetone. Analysis of solvent composition and dielectric constant has revealed specific solvent effects on the water-induced precipitation of cholesterol. Thermodynamic analysis of the precipitation phenomenon and the unique role of solvent structure on cholesterol precipitation has been discussed.

Model biological microemulsions: Part I--Phase behaviour and physicochemical properties of cholesteryl benzoate and sodium deoxycholate contained microemulsions.

Phase behaviour and some physicochemical properties of cholesteryl benzoate-contained microemulsions of xylene and heptane with water using sodium deoxycholate and butan-1-ol as surfactant and co-surfactant respectively have been studied. While the microemulsion area of xylene depends insignificantly on the surfactant/co-surfactant ratio, that of heptane shows appreciable dependence. At surfactant + co-surfactant percentage of 50 or above, both the systems become oil continuous. With respect to time and temperature, the microemulsion systems have been found to be very stable. At low percentage of water, the xylene system is considerably viscous; that of heptane is less viscous but shows viscosity maximum at 45% water. Cholesterol in xylene has given greater viscosity than cholesteryl benzoate. The equivalent conductance of both the systems increase with increasing water content and the values are comparable. Unlike normal electrolyte solutions, the products of equivalent conductance and viscosity (the Walden product) sharply rise with increased water content, which suggests a special mechanism of conduction via 'channel' formation. The overall rigidity of the microemulsions is suggested by their lower specific volumes and compressibilities at all compositions. The excess specific volumes and excess compressibilities at different percentages of water are presented.