Discovery of two novel laccase-like multicopper oxidases from Pleurotus citrinopileatus and their application in phenolic oligomer synthesis.

BACKGROUND: Laccases and laccase-like multicopper oxidases (LMCOs) oxidize a vast array of phenolic compounds and amines, releasing water as a byproduct. Their low substrate specificity is responsible for their tremendous biotechnological interest, since they have been used for numerous applications. However, the laccases characterized so far correspond to only a small fraction of the laccase genes identified in fungal genomes. Therefore, the knowledge regarding the biochemistry and physiological role of minor laccase-like isoforms is still limited. RESULTS: In the present work, we describe the isolation, purification and characterization of two novel LMCOs, PcLac1 and PcLac2, from Pleurotus citrinopileatus. Both LMCOs were purified with ion-exchange chromatographic methods. PcLac2 was found to oxidize a broader substrate range than PcLac1, but both LMCOs showed similar formal potentials, lower than those reported previously for laccases from white-rot fungi. Proteomic analysis of both proteins revealed their similarity with other well-characterized laccases from Pleurotus strains. Both LMCOs were applied to the oxidation of ferulic and sinapic acid, yielding oligomers with possible antioxidant activity. CONCLUSIONS: Overall, the findings of the present work can offer new insights regarding the biochemistry and variability of low-redox potential laccases of fungal origin. Low-redox potential biocatalysts could offer higher substrate selectivity than their high-redox counterparts, and thus, they could be of applied value in the field of biocatalysis.

Antiangiogenic activity of zinc and zinc-sorafenib combination using the chick chorioallantoic membrane assay: A descriptive study.

AIM: Zinc, a trace element, is known for downregulating several proangiogenic growth factors and cytokines. However, its antiangiogenic activity is not adequately studied. The present study was aimed to evaluate the possible antiangiogenic activity of zinc via the chick chorioallantoic membrane (CAM) assay. Furthermore, the antiangiogenic activity of the combination therapy of zinc with various doses of sorafenib, a tyrosine kinase inhibitor, was evaluated. MATERIALS AND METHODS: A pilot study was initially conducted so as to select suitable doses of zinc and sorafenib. The antiangiogenic activity after combining zinc 2.5 µg/embryo with sorafenib 1 and 2 µg/embryo was also evaluated. The antiangiogenic activity was quantified in terms of total length of blood vessels, number of junctions, number of branching points, and mean length of the blood vessels. RESULTS: Zinc 2.5 µg/embryo showed significant (P < 0.05) antiangiogenic activity, as compared to the control group. However, its effect was not comparable to that of sorafenib 2 µg/embryo. The combination of zinc 2.5 µg/embryo with sorafenib 2 µg/embryo did not show an additive/synergistic effect. The combination of zinc 2.5 µg/embryo with sorafenib 1 µg/embryo produced an antiangiogenic activity which was comparable (P > 0.05) to that of sorafenib 2 µg/embryo. CONCLUSION: Zinc caused significant antiangiogenic activity in the CAM assay. The lack of addition/synergism in the zinc-sorafenib combination could have been due to the variability in the dose/ratio selection. Addition of zinc to sorafenib therapy could improve treatment tolerability, reduce cost of therapy, and reduce the emergence of drug resistance. Future mechanistic studies could identify the exact pharmacodynamics of zinc as an angiogenesis inhibitor.

Attenuation of oxidative stress and neurotoxicity involved in the antidepressant-like effect of the MK-801(dizocilpine) in Bacillus Calmette-Guerin-induced depression in mice.

Background The emerging line of research suggests that neuro-inflammation and oxidative stress are linked to the development of depression-like behavior. The tryptophan metabolizing enzyme, indolamine 2,3-dioxygenase (IDO), serves as an important interface between chronic inflammation and depression. IDO is induced by pro-inflammatory cytokines and diverts tryptophan towards the kynurenine pathway, decreasing serotonin synthesis. Further, the metabolites of kynurenine pathway increase brain oxidative stress and also cause N-methyl-D-aspartate (NMDA) receptor-mediated exitotoxicity. The resulting oxidative damage and dysfunction in glutamatergic neurotransmission alters the network connectivity of the brain, which may be the further mechanism for emergence of depression-like symptoms. Methods A depression-like illness was induced in mice by injecting Bacillus Calmette-Guerin (BCG) suspended in isotonic saline at a dose of 107 CFU I.P. The mice were then divided into different groups and were administered MK-801 or normal saline for the next 21 days, after which a battery of behavior and biochemical tests were conducted to assess them. Results The BCG group had significantly reduced sucrose preference index and an increase in immobility time in forced swim test (FST) and Tail Suspension Test (TST) as compared to the saline group. There was also a significant increase in the brain MDA levels and a decline in the brain GSH levels. The hippocampal tissue from the BCG group had significantly more comet cells than the saline group. The NMDA receptor antagonist, MK-801, was able to reverse the BCG-induced depression-like behaviour. MK-801 also showed significant decrease in brain oxidative stress but failed to show significant protection against BCG-induced neurotoxicity observed in comet assay. Conclusions The NMDA receptor antagonist, MK-801, mitigated BCG-induced, depressive-like behavior in mice by improving the sucrose preference and decreasing the duration of immobility time in TST and FST. The overall improvement in depression-like behavior was accompanied by a reduction in brain oxidative stress and comet cells, thus suggesting the antioxidant and neuroprotective action of MK-801.

Comparison of fluoxetine and 1-methyl-L-tryptophan in treatment of depression-like illness in Bacillus Calmette-Guerin-induced inflammatory model of depression in mice.

BACKGROUND: The inflammatory response system has been implicated in the pathophysiology of major depression. The pro-inflammatory cytokines like interferon-γ induce the enzyme indoleamine-2,3-dioxygenase (IDO) of the kynurenine pathway of tryptophan metabolism. The induction of IDO reduces the availability of tryptophan for serotonin synthesis. Furthermore, the metabolites of kynurenine pathway have neurotoxic property, which along with decreased serotonin may account for depression-like illness. METHODS: The aim of this study was to compare the effects of treatment with fluoxetine and 1-methyl-L-tryptophan (1-MT) on Bacillus Calmette-Guerin (BCG)-induced inflammatory model of depression in mice. Behavioral tests included locomotor activity, forced swim test (FST) and tail suspension test (TST). Oxidative stress was assessed by examining the levels of thiobarbituric acid reactive species (TBARS) and non-protein thiols (NP-SH) in homogenized whole brain samples. Comet assays were performed to assess neurotoxicity. RESULTS: The results of this study demonstrate that BCG treatment resulted in an increase in duration of immobility in FST and TST as compared to the saline group. Further, it produced a significant increase in the brain TBARS levels and decrease in the brain NP-SH levels. The hippocampal tissue from BCG group had significantly more comet cells than the saline group. 1-MT and fluoxetine were able to reverse the BCG-induced depression-like behavior and the derangement in oxidative stress parameters. Fluoxetine and 1-MT also reversed the BCG-induced neurotoxicity in such mice. CONCLUSIONS: 1-Methyl-L-tryptophan exhibits antidepressant-like effect comparable to that of fluoxetine in treating BCG-induced depression-like behavior in mice.

Isotopic disequilibrium in Globigerina bulloides and carbon isotope response to productivity increase in Southern Ocean.

Oxygen and carbon isotope ratios in planktonic foraminifera Globigerina bulloides collected from tow samples along a transect from the equatorial Indian ocean to the Southern Ocean (45°E and 80°E and 10°N to 53°S) were analysed and compared with the equilibrium δ(18)O and δ(13)C values of calcite calculated using the temperature and isotopic composition of the water column. The results agree within ~0.25‰ for the region between 10°N and 40°S and 75-200 m water depth which is considered to be the habitat of Globigerina bulloides. Further south (from 40°S to 55°S), however, the measured δ(18)O and δ(13)C values are higher than the expected values by ~2‰ and ~1‰ respectively. These enrichments can be attributed to either a 'vital effect' or a higher calcification rate. An interesting pattern of increase in the δ(13)C(DIC) value of the surface water with latitude is observed between 35°S and~ 60°S, with a peak at~ 42°S. This can be caused by increased organic matter production and associated removal. A simple model accounting for the increase in the δ(13)C(DIC) values is proposed which fits well with the observed chlorophyll abundance as a function of latitude.

Pharmacological characterization of the first in class clinical candidate PF-05190457: a selective ghrelin receptor competitive antagonist with inverse agonism that increases vagal afferent firing and glucose-dependent insulin secretion ex vivo.

BACKGROUND AND PURPOSE: Ghrelin increases growth hormone secretion, gastric acid secretion, gastric motility and hunger but decreases glucose-dependent insulin secretion and insulin sensitivity in humans. Antagonizing the ghrelin receptor has potential as a therapeutic approach in the treatment of obesity and type 2 diabetes. Therefore, the aim was to pharmacologically characterize the novel small-molecule antagonist PF-05190457 and assess translational pharmacology ex vivo. EXPERIMENTAL APPROACH: Radioligand binding in filter and scintillation proximity assay formats were used to evaluate affinity, and europium-labelled GTP to assess functional activity. Rat vagal afferent firing and calcium imaging in dispersed islets were used as native tissues underlying food intake and insulin secretion respectively. KEY RESULTS: PF-05190457 was a potent and selective inverse agonist on constitutively active ghrelin receptors and acted as a competitive antagonist of ghrelin action, with a human Kd of 3 nM requiring 4 h to achieve equilibrium. Potency of PF-05190457 was similar across different species. PF-05190457 increased intracellular calcium within dispersed islets and increased vagal afferent firing in a concentration-dependent manner with similar potency but was threefold less potent as compared with the in vitro Ki in recombinant overexpressing cells. The effect of PF-05190457 on rodent islets was comparable with glibenclamide, but glucose-dependent and additive with the insulin secretagogue glucagon-like peptide-1. CONCLUSIONS AND IMPLICATIONS: Together, these data provide the pharmacological in vitro and ex vivo characterization of the first ghrelin receptor inverse agonist, which has advanced into clinical trials to evaluate the therapeutic potential of blocking ghrelin receptors in obesity and type 2 diabetes.

An improved method of high-precision determination of Δ(17)O of CO2 by catalyzed exchange with O2 using hot platinum.

RATIONALE: CO2 and O2 can exchange their oxygen isotopes rapidly in the presence of hot (~670 °C) platinum and this has led to a method for determining the δ(17)O value of a CO2 sample. We have improved the method to achieve a precision of 0.008 ‰ (1-σ standard deviation) in the determination of δ(17)O values. Such high precision is essential to identify the stratospheric component in tropospheric CO2 and use it for global carbon flux studies. The crucial issue in the accurate determination of the δ(17)O value is estimation of a correction factor, which depends on the amount ratio CO2/O2. An attempt was also made to investigate the mechanism of exchange with their controlling parameters. METHODS: The oxygen isotopes of a CO2 sample gas are exchanged with those of an appropriate amount of tank O2 in the presence of hot platinum. The pre-exchange CO2 and O2 gas samples as well as the post-exchange O2 sample are analyzed by isotope ratio mass spectrometry. A mixing model was developed involving the δ(18)O value of the CO2 and δ(17)O and δ(18)O values of pre- and post-exchange O2 to obtain the δ(17)O value of the CO2 sample. A correction to the measured value was determined to obtain the actual value with high accuracy and precision. RESULTS: To obtain a precision better than 0.01 ‰ requires the amount ratio CO2/O2 to be controlled to better than ~15 %. We also find that the oxygen isotopes are nearly homogeneously distributed between the O2 and the CO2 molecules. In addition, determination of the (16) O(13)C(18)O/(16)O(12)C(16)O isotopologue ratio in the CO2 shows that the abundance of (16)O(13)C(18)O is close to that expected for random partitioning of the isotopes among the CO2 isotopologues. CONCLUSIONS: The isotopic scrambling between O2 and CO2 that occurs on hot platinum allows one to accurately determine the δ(17)O values of CO2 through isotopic analysis of O2.

A new feature in the internal heavy isotope distribution in ozone.

Ozone produced by discharge or photolysis of oxygen has unusually heavy isotopic composition ((18)O/(16)O and (17)O/(16)O ratio) which does not follow normal mass fractionation rule: δ(17)O ∼ 0.52(*)δ(18)O, expressed as an anomaly Δ(17)O = δ(17)O - 0.52(*)δ(18)O. Ozone molecule being an open isosceles triangle can have the heavy isotope located either in its apex or symmetric (s) position or the base or asymmetric (as) position. Correspondingly, one can define positional isotopic enrichment, written as δ(18)O (s) or δ(18)O (as) (and similarly for δ(17)O) as well as position dependent isotope anomaly Δ(17)O (s) and Δ(17)O (as). Marcus and co-workers have proposed a semi-empirical model based in principle on the RRKM model of uni-molecular dissociation but with slight modification (departure from statistical randomness assumption for symmetrical molecules) which explains many features of ozone isotopic enrichment. This model predicts that the bulk isotope anomaly is contained wholly in the asymmetric position and the Δ(17)O (s) is zero. Consequently, Δ(17)O (as) = 1.5 (*) Δ(17)O (bulk) (named here simply as the "1.5 rule") which has been experimentally confirmed over a range of isotopic enrichment. We now show that a critical re-analysis of the earlier experimental data demonstrates a small but significant departure from this 1.5 rule at the highest and lowest levels of enrichments. This departure provides the first experimental proof that the dynamics of ozone formation differs from a statistical model constrained only by restriction of symmetry. We speculate over some possible causes for the departure.

Laboratory study of nitrate photolysis in Antarctic snow. II. Isotopic effects and wavelength dependence.

Atmospheric nitrate is preserved in Antarctic snow firn and ice. However, at low snow accumulation sites, post-depositional processes induced by sunlight obscure its interpretation. The goal of these studies (see also Paper I by Meusinger et al. ["Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry," J. Chem. Phys. 140, 244305 (2014)]) is to characterize nitrate photochemistry and improve the interpretation of the nitrate ice core record. Naturally occurring stable isotopes in nitrate ((15)N, (17)O, and (18)O) provide additional information concerning post-depositional processes. Here, we present results from studies of the wavelength-dependent isotope effects from photolysis of nitrate in a matrix of natural snow. Snow from Dome C, Antarctica was irradiated in selected wavelength regions using a Xe UV lamp and filters. The irradiated snow was sampled and analyzed for nitrate concentration and isotopic composition (δ(15)N, δ(18)O, and Δ(17)O). From these measurements an average photolytic isotopic fractionation of (15)ɛ = (-15 ± 1.2)‰ was found for broadband Xe lamp photolysis. These results are due in part to excitation of the intense absorption band of nitrate around 200 nm in addition to the weaker band centered at 305 nm followed by photodissociation. An experiment with a filter blocking wavelengths shorter than 320 nm, approximating the actinic flux spectrum at Dome C, yielded a photolytic isotopic fractionation of (15)ɛ = (-47.9 ± 6.8)‰, in good agreement with fractionations determined by previous studies for the East Antarctic Plateau which range from -40 to -74.3‰. We describe a new semi-empirical zero point energy shift model used to derive the absorption cross sections of (14)NO3 (-) and (15)NO3 (-) in snow at a chosen temperature. The nitrogen isotopic fractionations obtained by applying this model under the experimental temperature as well as considering the shift in width and center well reproduced the values obtained in the laboratory study. These cross sections can be used in isotopic models to reproduce the stable isotopic composition of nitrate found in Antarctic snow profiles.

Cholera outbreaks in South-East Asia.

This chapter highlights the cholera situation in South Asia and the Bay of Bengal region, the original 'homeland' of cholera. A detailed discussion of cholera outbreaks in individual countries in South-East Asia follows. The countries of the World Health Organization (WHO) SEARO (South-East Asia Region) region are discussed first, followed by discussions about the other countries in South-East Asia that do not fall within the purview of the WHO SEARO classification of the member countries of the region. Therefore, the chapter attempts to provide a comprehensive yet precise outline of the major cholera outbreaks that have occurred in the region over the years.

Naloxone blocks the beneficial effects of aqueous extract of Murraya koenigii (L.) Spreng leaves in models of pain.

AIM: This study investigated the antinociceptive effects of aqueous extract of Murraya koenigii (AEMK) leaves (200, 400 and 800 mg/kg, orally) on animal models of acute and persistent pain and its modulation by naloxone. MATERIALS AND METHODS: Antinociceptive effects were assessed using tail-flick, hot plate and formalin tests in mice. To differentiate between central and peripheral antinociceptive effect of AEMK, naloxone (2 mg/kg) was administered along with the 800 mg/kg dose of extract. Morphine was used as a standard drug. RESULTS: AEMK and morphine significantly increased the tail-flick latency (tfl) and paw licking/jumping latency in tail-flick and hot plate tests, respectively, in comparison to control. Also, in both the tests AEMK and morphine significantly increased the AUC0-120 min. In formalin test, AEMK (400 mg/kg and 800 mg/kg) and morphine significantly reduced licking time in both early and late phases in comparison to control. CONCLUSIONS: Thus, in all three pain models AEMK showed antinociceptive effect, which was blocked by naloxone suggesting the involvement of opioidergic central mechanism.

Oxygen isotope exchange between O2 and CO2 over hot platinum: an innovative technique for measuring Δ17O in CO2.

The isotopic composition of carbon dioxide provides a powerful tool and has been widely used for constraining the sources and sinks of atmospheric CO2. In this work, we demonstrate a simple, rapid, and clean way for measuring the triple oxygen isotope ratio of carbon dioxide with high precision. The method depends on isotope exchange between O2 and CO2 in the presence of platinum at high temperature and allows rapid measurement of Δ(17)O of CO2. The method has been established and confirmed through several tests by using artificially made CO2 with known Δ(17)O values. The analytical precision obtained for determining Δ(17)O in CO2 is 0.045‰ (1 - σ standard deviation).

Tobacco and alcohol: the relation to pulmonary tuberculosis in household contacts.

Tuberculosis is transmitted commonly by droplet nuclei and facilitated by weak immune system. Lowered immunity may be associated with cigarette smoking, tobacco chewing and alcohol consumption. The co-relationship between these all factors to TB should be explored. This study aims to detect the hidden household contacts (HC) cases early and to examine the relative contribution of tobacco and alcohol use to the risk of TB. Across-sectional study was in Dharan among HCs. From June 2009 to May 2010, 184 index cases with sputum smear positive for AFB and their 802 HCs were included. Three sputum specimens were collected from each HCs and examined microscopically for AFB detection. AFB were detected in sputum of 13 (1.6%) HCs. The association between habits (alcohol user and smoking) and TB was found except with chewing tobacco user (P > 0.05). The risk of contact TB was 4 and 8 times greater in smoker (OR = 3.94 95% CI = 1.26-12.26, P < 0.05) and alcoholic (OR = 8.23 95% CI = 2.71-24.98, P < 0.05) HCs respectively. This study has revealed smoking and alcohols as the risk factors for tuberculosis. Effective campaign to discourage use of alcohol and tobacco, and awareness programme about the mode of transmission of TB are needed in community.

Pneumonia in South-East Asia Region: public health perspective.

Globally, pneumonia is the leading cause of death in young children and burden of disease is disproportionately high in South-East Asia Region of WHO. This review article presents the current status of pneumonia disease burden, risk factors and the ability of health infrastructure to deal with the situation. Literature survey was done for the last 20 years and data from country offices were also collected. The estimated incidence of pneumonia in under five children is 0.36 episodes per child, per year. Risk factors are malnutrition (40% in India), Indoor air pollution, non-breast feeding, chronic obstructive pulmonary disease, etc. Strengthening of health care delivery system for early detection and treatment and as well as minimization of preventable risk factors can avert a large proportion of death due to pneumonia.

Measurement of the 17O-excess (Δ17O) of tropospheric ozone using a nitrite-coated filter.

RATIONALE: The (17)O-excess (Δ(17)O) of tropospheric ozone (O(3)) serves as a useful marker in studies of atmospheric oxidation pathways; however, due to the complexity and expense of currently available analytical techniques, no systematic sampling campaign has yet been undertaken and natural variations in Δ(17)O(O(3)) are therefore not well constrained. METHODS: The nitrite-coated filter method is a new technique for O(3) isotope analysis that employs the aqueous phase NO(2)(-) + O(3) → NO(3)(-) + O(2) reaction to obtain quantitative information on O(3) via the oxygen atom transfer to nitrate (NO(3)(-)). The triple-oxygen isotope analysis of the NO(3)(-) produced during this reaction, achieved in this study using the bacterial denitrifier method followed by isotope-ratio mass spectrometry (IRMS), directly yields the Δ(17)O value transferred from O(3). This isotope transfer process was investigated in a series of vacuum-line experiments, which were conducted by exposing coated filters to O(3) of various known Δ(17)O values and then determining the isotopic composition of the NO(3)(-) produced on the filter. RESULTS: The isotope transfer experiments revealed a strong linear correlation between the Δ(17)O of the O(3) produced and that of the oxygen atom transferred to NO(3)(-), with a slope of 1.55 for samples with bulk Δ(17)O(O(3)) values in the atmospheric range (20-40‰). This finding is in agreement with theoretical postulates that place the (17) O-excess on only the terminal oxygen atoms of ozone. Ambient measurements yield average Δ(17)O(O(3))(bulk) values in agreement with previous studies (22.9 ± 1.9‰). CONCLUSIONS: The nitrite-coated filter technique is a sufficiently robust, field-deployable method for the determination of the triple-oxygen isotopic composition of tropospheric O(3). Further ambient measurements will undoubtedly lead to an improved quantitative view of natural Δ(17)O(O(3)) variation and transfer in the atmosphere.

17O excess transfer during the NO2 + O3 → NO3 + O2 reaction.

The ozone molecule possesses a unique and distinctive (17)O excess (Δ(17)O), which can be transferred to some of the atmospheric molecules via oxidation. This isotopic signal can be used to trace oxidation reactions in the atmosphere. However, such an approach depends on a robust and quantitative understanding of the oxygen transfer mechanism, which is currently lacking for the gas-phase NO(2) + O(3) reaction, an important step in the nocturnal production of atmospheric nitrate. In the present study, the transfer of Δ(17)O from ozone to nitrate radical (NO(3)) during the gas-phase NO(2) + O(3) → NO(3) + O(2) reaction was investigated in a series of laboratory experiments. The isotopic composition (δ(17)O, δ(18)O) of the bulk ozone and the oxygen gas produced in the reaction was determined via isotope ratio mass spectrometry. The Δ(17)O transfer function for the NO(2) + O(3) reaction was determined to be: Δ(17)O(O(3)∗) = (1.23 ± 0.19) × Δ(17)O(O(3))(bulk) + (9.02 ± 0.99). The intramolecular oxygen isotope distribution of ozone was evaluated and results suggest that the excess enrichment resides predominantly on the terminal oxygen atoms of ozone. The results obtained in this study will be useful in the interpretation of high Δ(17)O values measured for atmospheric nitrate, thus leading to a better understanding of the natural cycling of atmospheric reactive nitrogen.

Effectiveness of an educational feedback intervention on drug prescribing in dental practice.

BACKGROUND: Irrational use of drugs as well as inappropriate and over drug prescribing leads to unnecessary expenditures and emergence of resistant bacterial strains. Feedback intervention on drug prescribing habits and face to face educational intervention of prescription audit would be effective in rationalizing prescribing practices. OBJECTIVE: To measure the impact of educational feedback intervention on the prescribing behavior of dental surgeons. METHODS: Prospective audit of twelve hundred outpatients prescriptions in dental OPD at BPKIHS of those dental surgeon who attended the educational intervention session was collected randomly by trained persons on customized data collection sheet before and after educational intervention. RESULTS: A total 1200 prescription were collected, 300 before and 300 after intervention period at the internal of one month, three months and six months. Majority of the prescriptions (39.33%) contained four drugs but after intervention, prescriptions contained mostly one drug, 73% in first month, 78.67% in third month and 65.34% in six month. Mean number of drugs per prescription after intervention were decreased. There was increased number of generic names of drugs after intervention. Amoxicillin, Metronidazole, Chlorhexidine, Povidone iodine gargle, Nimesulide, Ibuprofen, Ibuprofen + paracetamol, and Paracetamol were most commonly prescribed by dental prescribers before and after intervention. Selection of antimicrobial was done on empirical basis which was correct because Amoxicillin concentration reaches effectively in gingival crevicular fluid and Metronidazole covered effectively against anaerobic bacteria were found in orodental infection. The uses of topical anti-infective preparation as irrigants of choice that can kill majority of micro-organisms found is root canal and dental tubules and minimize systemic use of antimicrobials. Nimesulide prescribing needs to be rationalized. CONCLUSION: Feedback educational intervention of prescription audit is effective to improve their prescribing behaviors and rationalize drug utilization pattern for the benefit of the patients.

In vitro activity of cefoperazone-sulbactam combination against gram negative bacilli.

Cefoperazone is a â-lactam antimicrobial and Sulbactam is an irreversible â-lactamase inhibitor. The objective of this study was to know the susceptibility pattern of gram negative bacilli (GNB) towards cefoperazone-sulbactum. All GNB isolated from different clinical samples during the period of May, 2010 to Aug, 2010 were tested for susceptibility to cefoperazone-sulbactum, meropenem, ceftazidime, cefotaxime, ceftriaxone, chloromphenicol, cotrimoxazole, ampicillin, amikacin, nalidixic acid, ciprofloxacin, carbenicillin and piperacillin using standard Kirby-Bauer disc diffusion antimicrobial susceptibility testing method. The susceptibilities were recorded according to CLSI guidelines. A total of 406 GNB were isolated (urine: 66.7%, pus: 19.2%, and blood: 7.9%). Escherichia coli (54.4%) was most frequently isolated organisms followed by Acinetobacter species (17.7%), Klebsiella pneumoniae (9.1%) and Pseudomonas species (6.1%). Overall, 11.8% of isolates showed resistance to cefoperazone-sulbactam. Frequencies of isolates showing resistance to meropenem and amikacin were 14.7% and 26.25% respectively. Only 3.9% of Escherichia coli isolates showed resistance to cefoperazone-sulbactam. For other organisms, their lowest frequency ranging from 0-20%, exhibited resistance to meropenem. In Pseudomonas spp, in-vitro activity of amikacin was also better as only 11.1% isolates showed resistance to it. This study demonstrated the in-vitro synergistic effect of cefoperazonerazone-sulbactam and meropenem having good activity against GNB compared to the activity of other commonly tested antimicrobials. Cefoperazone-sulbactam can be recommended for the clinical practice against GNB exhibiting resistant to other antimicrobials as it is cheaper alternative to meropenem. Our results also focused on the continuous surveillance of the trends and features of resistance of common antimicrobials.

Etiological agents of corneal ulcer: five years prospective study in eastern Nepal.

To identify the most common isolates from the corneal ulcers with antimicrobial pattern of bacterial isolates. All patients with suspected corneal ulceration presenting to BP Koirala Institute of Health Sciences from Jan 2004 - Dec 2008 were evaluated. Corneal scraping was performed and processed for direct microscopy, bacteriological and fungal culture. Bacterial isolates were subjected to antimicrobial susceptibility testing. Of 351 specimens examined, growth of etiological agents were obtained in 278 (79.20%). Of these, 113 (40.65%) had pure fungal growth, 108 (38.85%) had pure bacterial growth and 57 (20.50%) had mixed fungal and bacterial infection. The commonest fungal pathogen was Aspergillus spp 50 (33.33%) followed by Fusarium spp 19 (12.66%). Staphylococcal aureus 57 (44.53%) was isolated as commonest bacterial agent. Coagulase Negative Staphylococci 20 (15.6%) was second in the list. Pseudomonas spp 12 (9.40%) was the most common gram negative bacilli isolated. Most of the bacterial isolates were sensitive to commonly used antibiotics. Corneal Ulcer is a common problem in eastern Nepal. Knowledge of both fungal and bacterial agents associated with this condition is of value for the prevention and management of corneal ulcers and their complications.

Prevalence of tuberculosis in household contacts of sputum smears positive cases and associated demographic risk factors.

Pulmonary tuberculosis (PTB) is transmitted by aerosolized droplets nuclei. Home is the vulnerable place for transmission of this disease to its contacts. Risk factors associated with this contact transmission may differ according to locality. This study aims to determine the prevalence of household contact (HC) PTB and examine the risk factors contributing to it. A cross-sectional study was conducted to determine the prevalence of HC TB among HCs aged > 5 years in Dharan. During the study period (June 2009 - May 2010), 184 index cases with sputum smear positive for AFB and their 802 HCs were included. Three sputum specimens were collected from each HCs and examined microscopically for AFB detection. The prevalence of HC TB was found to be 1.6%. The result was statistically associated (P < 0.05) with illiterate HCs (OR= 5.77, 95%CI =1.52-21.81), close proximity with ICs (OR=3.07, 95%CI = 1.02-9.25), primary relatives to ICs (OR= 4.85, 95%CI = 1.07-22.05) and slum dweller (OR = 4.56, 95%CI = 1.25-16.71). Similarly, AFB positivity was associated (P<0.05) with household crowding (OR = 7.46, 95%CI = 2.36-23.49), room size < or = 10 x 10 feet (OR=4.05, 95%CI = 1.23-13.25), firewood user while cooking (OR = 5.96, 95%CI = 1.92-18.45). The prevalence of HCs tuberculosis is found to be 1.6%. Poverty, illiteracy, overcrowding, close proximity, close relation with ICs, firewood while cooking, slum dweller, are major factors highlighted by this study as risk factors of contact TB. Our results recommend a much better contact tracing and treatment program.