Education: the key to curb HIV and AIDS epidemic.

Overwhelming impact has been established among different aspects and burden of incurable HIV and AIDS is increasing day-by-day globally. The aim of this article is to discuss the potential benefits and strengths of an education system in the absence of remedy and help to develop future strategies. Education has great impact on HIV and AIDS and vice-versa. An education plays a vital role to curb the transmission of HIV and AIDS thorough capacity building, provides information, reduces vulnerability, empowerment, improve life skill, maintain equity, reduce dependence, stigma, and discrimination, where are abundance foundations for HIV infection. HIV and AIDS has role for devastation of education system and level which has great impact on productivity, economic growth, demand, supply and daily life of human being. Low and middle income countries needs to be improve recording and reporting systems related to impact of HIV and AIDS on education. By analyzing preceding evidences, policy makers or governance feels to reformulate policies relating to education and health. Evidence based policy and program will be more useful to address distressing squall of epidemic.

Current fluoroquinolone susceptibility criteria for Salmonella needs re-evaluation.

BACKGROUND: Disc diffusion technique is the routine susceptibility testing procedure for isolates of enteric fever, the most common clinical diagnosis among febrile patients in Nepal. OBJECTIVE: To evaluated the current fluoroquinolones (FQs) susceptibility criteria and nalidixic acid screening test in Salmonella enterica serovar Typhi and Paratyphi A. METHODS: S. Typhi and Paratyphi A strains isolated from 443 suspected enteric fever patients visiting National Public Health Laboratory (NPHL) during April through October 2008 were analyzed. All isolates were confirmed by standard microbiological procedures including serotyping. Antibiotic susceptibility testing was performed by using Kirby Bauer disc diffusion method and Clinical and Laboratory Standards Institute (CLSI) approved interpretive criteria. Agar dilution method was used to determine Minimum Inhibitory Concentration (MIC) of ciprofloxacin, ofloxacin and nalidixic acid. RESULT: Out of 41 Salmonella isolates, 80.49% were nalidixic acid resistant, with S. Paratyphi A showing higher resistance rate (88.23%) compared to S. Typhi (75%). The difference in both MIC and zone diameter in nalidixic acid susceptible and nalidixic acid resistant isolates was found to be significant (P < 0.001) and decreased susceptibility to FQs was strongly correlated (sensitivity and specificity of 100%) with resistance to nalidixic acid. Regression analysis of MIC against zone diameter based on the current CLSI recommended guidelines suggests that accommodation of current susceptible and resistant MIC requires increase in the zone diameter of ciprofloxacin and ofloxacin. CONCLUSION: Before using these drugs for management of enteric fever, appropriate identification of Salmonella isolates with reduced susceptibility to FQs is essential to limit the possible treatment failure and development of highly resistant strains. The current FQs susceptibility break point criteria for Salmonella need re-evaluation.

Holographic sensors for the detection of bacterial spores.

Holographic sensors for the detection of Bacillus species spore germination and vegetative growth are described. Reflection holograms were fabricated using a diffusion method for the distribution of ultra-fine silver bromide grains into pre-formed polymer films, followed by holographic recording using a frequency doubled Nd:YAG (532 nm) laser. Changes in holographic replay wavelength or diffraction intensity were used to characterise the swelling behaviour or structural integrity of a range of holographic matrices in response to various extracellular products of bacterial spore germination and vegetative metabolism. Divalent metal ion-sensitive holograms containing a methacrylated analogue of nitrilotriacetic acid (NTA) as the chelating monomer were successfully used to monitor Ca2+ ions released during B. subtilis spore germination in real-time, which was within minutes of sample addition; the holographic response manifested as a 16 nm blue-shift in diffraction wavelength over the progress of germination. Similarly, pH-sensitive holograms comprising methacrylic acid (MAA) as the ionisable monomer were responsive to changes in pH associated with early vegetative metabolism following germination of B. megaterium spores; a visually perceptible blue-shift in holographic replay wavelength of 75 nm was observed. Casein and starch-based holographic matrices, prepared by co-polymerisation of the appropriate substrate with acrylamide, were used to detect exo-enzymes released during later stages of B. megaterium and B. subtilis vegetative cell growth; holographic responses of both matrices were visible as a reduction in diffraction intensity due to progressive fringe disruption caused by enzymatic cleavage. The combined monitoring of various germination and growth events using the range of aforementioned holographic sensors provides a novel, comprehensive means for the detection of viable bacterial spores.

Horizontal Transfer of Spinosad in Coptotermes formosanus (Isoptera: Rhinotermitidae).

Slow-acting and nonrepellent termiticides are possible candidates for nestmate to nestmate transfer called horizontal transfer. For the horizontal transfer study of spinosad, Coptotermes formosanus Shiraki was released in sand and soil at 1, 25, and 50 ppm Entrust(®) for 1 h and then mixed with healthy untreated termites for 21 d at the ratio of 1:1. Donor and recipient termites began to contact and groom each other immediately after release. Mortality of termites was recorded at 1, 3, 7, and 14 d after treatment. Spinosad was more effectively transferred in sand than in soil. In sand at 25 and 50 ppm, significantly high mortality of donors and recipients was observed after 7 d. When termites were exposed to treated soil at day 21, all three concentrations resulted in significantly higher mortality compared to the control. In our laboratory study, spinosad was effectively transferred by donor termites. Transfer of spinosad depended on its bioavailability and concentration. Further study is needed to address its effects against C. formosanus under field conditions.

Toxicity and Nonrepellency of Spinosad and Spinetoram on Formosan Subterranean Termites (Isoptera: Rhinotermitidae).

Spinosyn products, spinosad and spinetoram, are widely used to control various agricultural pests. Spinosad has been tested on Kalotermitidae and Termitidae but not on Rhinotermitidae, the most destructive of termite families. In this study, we tested the effect of spinosad and spinetoram on Coptotermes formosanus Shiraki. Both no-choice and choice tests were conducted using three concentrations, 1 ppm, 25 ppm, and 50 ppm, of the spinosyn products Entrust, Tracer, and Radiant on three substrates, sand, soil, and filter paper. In the no-choice test in sand, >85% mortality was observed at 25 and 50 ppm after 1 d of exposure followed by 100% mortality at 7 d. Similarly, after 7 d at 25 and 50 ppm in soil and filter paper, 100% mortality was observed, but compared to sand at 1 d, mortality was low. In the two-choice test, observations before the onset of termite mortality showed that none of the products or concentrations was repellent. Likewise, in the multiple-choice test, there was no repellency or preference of termites among 1 ppm, 25 ppm, 50 ppm, control, and release chamber at all three concentrations, and the tunnel area in the control and treated choices were not significantly different. These findings support the nonrepellent attribute of spinosyns on C. formosanus .

Smoking Susceptibility and Intention to Smoke among Secondary School Adolescents in Nepal.

BACKGROUND: Smoking Susceptibility (SS) and Intention to Smoke (IS) are important characteristics of early stages of smoking career of adolescents. Several psychosocial factors play crucial roles in prevention of smoking initiation among adolescents. This study utilized the recent Global Youth Tobacco Survey (GYTS) data of Nepal with the main aim to correlate factors associated with SS and IS. METHODS: Nationally representative data on 2,878 school going Nepalese adolescents were collected through second GYTS using two-stage cluster sampling. An anonymous and self -administrated questionnaire was used to collect information on smoking related variables. We applied multivariable logistic regression to examine relationship between risk factors (demographic, environmental, motivating and programmatic variables) and SS and IS. RESULTS: The prevalence of SS and IS among never smokers was 22.8% (95% CI: 21.2, 24.5) &11.4% (10.2, 12.6) respectively. Factors found associated with respect to different variables were as follows: SS -being a male (AOR: 1.32; 95% CI 1.04, 1.69), friend smoking (1.97; 1.53, 2.52), offered free cigarettes (1.41; 1.03, 1.93), parental smoking (1.68; 1.32, 2.12); IS -being a male (1.43; 1.04, 1.97), and parental tobacco use (1.52; 1.11, 2.08). The following factors were protective measures for SS and IS - age, and antismoking messages. CONCLUSIONS: Smoking susceptibility and intention to smoke is prevalent in Nepalese school going adolescents. Several aforementioned factors are responsible to become susceptible and intention to smoke. Therefore, an understanding of the influencing factors of adolescents provides important insight for comprehensive school based tobacco intervention programs.

In vitro Temocillin efficacy against extended spectrum ß-lactamase producing multidrug resistant gram negative bacterial isolates from Nepal.

Temocillin is relatively more stable against most ß-lactamases and requires re-evaluation to include it in common clinical practice as a therapeutic alternative. At the National Reference Laboratory of Nepal, we evaluated multidrug resistance (MDR) and extended spectrum ß-lactamase (ESBL) phenotypes among 292 gram-negative clinical bacterial isolates of 18 different genera during 2009/2010 by Kirby-Bauer disc diffusion method following CLSI guidelines. ESBL screen positive isolates were tested for Temocillin efficacy by disc diffusion method following British Society of Antimicrobial Chemotherapy (BSAC) guidelines and other antibiotics following Clinical and Laboratory Standards Institute (CLSI) guidelines. Of the 292 isolates, 75.0% isolates were MDR, among which 61.6% were primarily screened positive for ESBL production but only 38.8% were confirmed as ESBL producers. We report relatively lower Temocillin resistance of 28.9% and 15.6% among MDR and ESBL positive populations, respectively. Among ESBL positive isolates, no Proteus mirabilis, 19.7% Escherichia coli and 33.3% Klebsiella oxytoca showed resistance to Temocillin, although such resistance was higher among Acinetobacter spp. (66.7%) and K. pneumoniae 50.0%. Among ESBL negative isolates, none of the K. oxytoca and few (13.3%) Acinetobacter spp. were resistant to Temocillin, while all Citrobacter freundii, Pseudomonas aeruginosa (85.7%) and K. pneumoniae (66.7%) showed Temocillin resistance. Only 14.8% and 3.0% of total MDR isolates were resistant to Imipenem and Meropenem, respectively. However, Imipenem resistance was remarkably high (86.7%) among ESBL negative Acinetobacter spp. than Meropenem (13.3%). Temocillin showed comparable efficacy against MDR and ESBL producing bacterial isolates and could be a next therapeutic option.

Antibiotic resistance pattern and plasmid profiling of thermotolerant Escherichia coli isolates in drinking water.

BACKGROUND: Antibiotic resistant Escherichia coli is potential source of transmission of resistance to other water borne pathogens where plasmid borne resistance is most significant. METHODS: Drinking water samples were collected from different water sources: that is to say- tap, well and spring from different places of Kathmandu where E. coli and thermotolerant E. coli were isolated using membrane filtration technique. Antibiotic susceptibility was determined using a modified Kirby Bauer disc diffusion method and thermotolerant E. coli isolates from tap water were subjected for plasmid profiling. RESULTS: Type of water sources were not associated with the presence of coliform (P=0.155) and thermotolerant coliform (P=0.235) but the significant association was observed in thermotolerant coliform and thermotolerant E. coli for all sources tap (P=0.029), well (P=0.028), spring (P=0.05) but total coliform and E. coli association was found for well (P=0.01). All E. coli and thermotolerant E. coli isolates were susceptible to Ofloxacin, Chloramphenicol and Cotrimixazole. Resistance to Cefexime, Amikacin, Nalidixic acid, Amoxicillin, Tetracycline were 17 (54.8%), 9 (29%), 11 (35.5%), 25 (80.6%), 29 (93.5%) and 19 (57.6%), 12 (36.4%), 13 (39.4%), 31 (94%), 33 (100%) was observed in E. coli and thermotolerant E. coli respectively where 25 (75.8%) thermotolerant E. coli and 22 (70.9%) E. coli were observed with multiple drug resistance patterns. Single band of plasmid were observed in three MDRs and one non-MDR isolates and size varied from 2kb to >10kb. All Nalidixic acid resistant thermotolerant E. coli were found to harbor a plasmid. CONCLUSIONS: Presence of plasmid in Nalidixic acid resistant thermotolerant E. coli heightens public health issue and the need of monitoring Quinolone resistance bacteria in environment.

Application of WHONET in the Antimicrobial Resistance Surveillance of Uropathogens: A First User Experience from Nepal.

INTRODUCTION: WHONET is a freely downloadable, Windows-based database software which is used for the management and analysis of microbiology data, with a special focus on the analysis of antimicrobial susceptibility test results. Urinary Tract Infections (UTI) are a common medical problem and they are responsible for notable morbidity among young and sexually active women. OBJECTIVES: The major objective of this study was the utilization and application of the WHONET program for the Antimicrobial Resistance (AMR) surveillance of uropathogens. METHODS: A total of 3209 urine samples were collected from patients who visited Manipal Teaching Hospital with a clinical suspicion of UTI, during December 2010 to July 2011. The isolation and characterization of the isolates were done by conventional methods. Antimicrobial Susceptibility Testing (AST) was performed by Kirby Bauer's disc diffusion method. The data entry and analysis were done by using the WHONET 5.6 software. RESULTS: Out of the 3209 specimens, 497 bacterial isolates were obtained and they were subjected to AST. Escherichia coli (66.2%) was the commonest bacterial isolate, followed by Enterococcus species (9.3%), Staphylococcus aureus (5.0%), and Klebsiella pneumoniae (4.2%). Among the gram-negative enteric bacilli, a high prevalence of resistance was observed against ampicillin and ciprofloxacin. The gram negative nonfermenters exhibited a high degree of resistance to ceftazidime. Staphylococcus species. showed a moderately high resistance to co-trimoxazole. One isolate was Vancomycin Resistant Enterococci (VRE). CONCLUSION: This study, a first of its kind which was done in Nepal, was carried out by using the WHONET software to monitor, analyze and share the antimicrobial susceptibility data at various levels. This study was also aimed at building a surveillance network in Nepal, with the National Public Health Laboratory, Nepal, acting as a nodal centre. This would help in the formulation of antibiotic policies and in identifying hospital and community outbreaks at the nodal centre, as well as in sharing information with the clinicians at the local level.

Studies on extended spectrum beta lactamase (ESBL) producing salmonella isolates from clinical samples of Nepal.

Present study was carried out among the patients of age 2-60 years from November 2009 to November 2011 to assess the production of Extended Spectrum Beta Lactamase (ESBL) by salmonella enterica serotype (Typhi and paratyphi A) at Kanti Children's Hospital (KCH), Nepal Medical College (NMC), Kathmandu Medical College (KMC), National Public Health Laboratory (NPHL) and Sankata Laboratory (SKL) of Nepal. Blood cultures were obtained from 4,820 patients with febrile illnesses. 400 strains of salmonella enterica were isolated. Antibiotic susceptibility testing was carried out using disk diffusion method by Kirby-Bauer technique and ESBL screening were done by Double Disk Synergy Test (DDST), following the Clinical and Laboratory Standard Institute (CLSI) recommendations for Escherichia coli. Male had higher infection (56%) than female (44%). Highest number of culture positive cases were (37%) in 10-19 years of age groups. Highest episodes of enteric fever cases occurred during April - June (45%) followed by July-September (35%). Among the total isolates 286 (72%) were Multidrug resistance (MDR). All the Multidrugs resistance salmonella, resistant to third generation Cephlospornis were ESBL producers.

The burden of dengue infection in some vulnerable regions of Nepal.

Dengue is an emerging mosquito borne disease of public health importance in Nepal. A descriptive cross sectional study was carried out to estimate sero-prevalence and distribution pattern of dengue in certain vulnerable regions of Nepal from June to September 2009. A total of 460 venous blood samples were collected from individuals experiencing a febrile illness clinically consistent with dengue infection visiting nearby hospitals of Kanchanpur, Kailali, Banke, Dang and Chitwan districts. The sero-prevalence of dengue virus specific IgM was determined by enzyme linked immunosorbent assay (ELISA) kit. The anti-dengue IgM positivity was found to be 12.17%. The higher frequency of positive cases (16.4%) were from age group 20-40 years followed by < 20 years age group with 9.7% and 5.3% from > 40 years age group. The association between dengue infection and age is found to be statistically significant (p < 0.05). The male:female ratio was determined as 1.3:1 in IgM positive population. Among sampling areas, Kanchanpur showed highest prevalence of dengue infection (15.5%) followed by Chitwan (11.7%), Kailai (11.1%), Banke (10.7%) and Dang (8.3%). Similarly, 94.6% of the positive cases were indigeneous and had no history of travel to other countries. Dengue is firmly established in terai region with increasing trends of infection and expansion into newer areas raising a public health threat. Regular epidemiological studies are suggested which could further reveal the contributing factors associated with dengue virus infection and help in formulating strategies in reducing the transmission rate and control of the infection.

Acute dengue infection in the western terai region of Nepal.

INTRODUCTION: Dengue fever is an emerging mosquito borne disease in Nepal claiming substantial morbidity and mortality. The objective of the study was to find out frequency of acute dengue infection in patients from the hospitals of the western Nepal. METHODS: The study was conducted between August 2007 and July 2008 in patients visiting hospitals of the western terai of Nepal with chief complains of fever. The sero-diagnosis of acute dengue infection was determined by enzyme linked immunosorbent assay among 239 patients visiting Lumbini Zonal Hospital, Butwal; Bheri Zonal Hospital, Nepalgunj; Bardiya District Hospital, Bardiya and Mahakali Zonal Hospital, Mahendranagar. RESULTS: The anti-dengue IgM positivity was 29.3%. There was slight male preponderance with a male to female ratio of 1.2:1. Out of the total positive cases, the highest positive cases (75.7%) were from the age group 15 - 50 years followed by < 15 years old (15.7%). Out of four hospitals, the highest positive cases (54.3%) were in Lumbini Zonal Hospital, Butwal. The age and gender were independent predictors to dengue virus infection. The highest numbers of dengue positive cases were in October (52.6%). The association between dengue disease and the month was statistically significant. CONCLUSIONS: The dengue positivity was estimated in acute patients from hospitals of western Nepal by enzyme immunoassay. Therefore, the serological marker can be used to diagnose acute patients of dengue during outbreaks.

Extended spectrum â-lactamase producing multidrug resistant clinical bacterial isolates at National Public Health Laboratory, Nepal.

Extended Spectrum â-lactamase (ESBL) producing multidrug resistant bacteria complicate therapeutic management and limit treatment options. Therefore, detection of ESBL-producing multidrug resistant (MDR) pathogens has a paramount importance. Between April 2009 and January 2010, a prospective study was carried out in National Public Health Laboratory with an objective to determine the status of ESBL producing MDR bacterial isolates from different clinical samples. Identification of the isolates was done by standard microbiological techniques and antibiotic susceptibility testing was done by Kirby Bauer disc diffusion method following Clinical and Laboratory Standard Institute (CLSI) guidelines. ESBL screening among MDR isolates was done using Ceftriaxone, Aztreonam, Cefotaxime, Ceftazidime and Cefpodoxime followed by confirmation using MASTDISCS ID ES2L Detection Discs (CPD10). Data analysis was done by SPSS 16 software. Of the 314 bacterial isolates from 1601 different clinical specimens, 199 (63.4%) were MDR. Cefotaxime was found the reliable screening agent for ESBL detection with sensitivity and positive predictive value of 98.6% and 76.4% respectively. Sixtey nine (62.7%) isolates of the 110 tested MDR isolates were ESBL positive with at least one of the Combined Disk (CD) Assays. Escherichia coli (80%) was the major ESBL producer followed by Klebsiella pneumoniae (5.8%). A statistically significant relationship was found between increasing spectrum of drug resistance and ESBL production (p<0.05). Thus it is concluded that a higher rate of ESBL production prevail among MDR clinical bacterial isolates underscoring the need for routine ESBL detection in clinical laboratories.

Study of rifampicin and isoniazid resistance mutation genes of M. tuberculosis isolates in Nepal.

We studied the rifampicin (RIF) and isoniazid (INH) resistant genes in Mycobacterium tuberculosis isolated from sputum samples of re-treated TB cases using phenotypic drug susceptibility test (DST) and rapid molecular method (Genotype; MTBDR plus, Hains Life Science, Nehren, Germany). Of the total 207 isolates included in this study, 90 (42.0%) were RIF resistant, 107 (50.7%) were INH resistant whereas 86 (41.5%) were multidrug resistant (MDR) by DST. According to genotypic analysis, 37.0% (77/207) were RIF resistant, 50.2% (105/207) INH resistant and 70 (33.8%) were MDR. Among the total 90 RIF resistant isolates, 85.5% (77/90) showed mutation in 81 bp of rpoB gene and the mutation locus were distributed as follows; MUT1 Asp516Val (16.7%; 15/90), MUT2A His526Tyr (6.6%; 6/90), MUT2B His526Asp (5.5%; 5/90) and MUT3 Ser531Lue (56.7%; 51/90). Among the total 107 INH resistant isolates, the mutation located in katG gene was 98.1% (105/107) and in inhA MUT1 gene was (16.8%; 18/107). The mutation locus were distributed as follows; MUT1 Ser315Thr (77.6%; 83/107), MUT2 Ser315Ile (3.7%; 4/107) in katG and in inhA MUT1Cys15Thr (16.8%; 18/107). The highest frequency of mutations in rpoB gene was found at the region of codon Ser531Leu (56.7%) while the frequency of mutation in katG and inhA gene were found at the region of codon Ser315Thr (77.6%) and Cyst15Thr (17.1%), respectively. The rapid molecular test kit used in this study was found to be sensitive as well as specific for detection of RIF and INH resistant gene and also helpful in early detection of MDR-TB.

Salmonella enterica serovar Paratyphi A: an emerging cause of febrile illness in Nepal.

With an aim to evaluate the isolation rate and antibiotic susceptibility pattern in Salmonella enterica serovar Typhi and S. Paratyphi A, 656 blood samples collected from clinically diagnosed enteric fever patients at National Public Health Laboratory, Nepal during January through December 2008 were processed. Isolates were identified by standard microbiological procedures including serotyping. Antibiotic susceptibility testing was performed by disc diffusion method and minimum inhibitory concentration (MIC) to ciprofloxacin, ofloxacin and nalidixic acid was determined by agar dilution method following CLSI guidelines. Altogether 59 isolates of S. Typhi (49.15%) and S. Paratyphi A (50.85%) were recovered. A total of 80% isolates were resistant to nalidixic acid with S. Paratyphi A (93%) showing significantly higher resistance (P < 0.05) compared to S. Typhi (66%). The nalidixic acid resistant S. Paratyphi A strains required significantly higher MICs (P < 0.001) to quinolone (MIC expressed as mean +/- SD for nalidixic acid 477.87 +/- 87.02 microg/mL, ofloxacin 1.8 +/- 0.63 microg/mL, ciprofloxacin 0.62 +/- 0.3 microg/mL) compared with that of S. Typhi (nalidixic acid 173.18 +/- 72.03 microg/mL, ofloxacin 0.43 +/- 0.11 microg/mL, ciprofloxacin 0.25 microg/mL). Increased MIC of fluoroquinolone (FQ) is of particular concern in emerging strains of S. Paratyphi A as exposure to these drugs fuels up further development of full FQ resistant populations. Use of FQs as the first-line drugs for empirical therapy and management of enteric fever in areas where these strains are prevalent is questionable and requires an urgent review.

Resistotypes of Vibrio cholerae 01 Ogawa Biotype El Tor in Kathmandu, Nepal.

Cholera continued to be a major diarrheal illness in Nepal and antibiotic resistance has appeared as a serious problem in cholera management. The study aimed at analyzing the distribution pattern of the resistotypes (R-types) of Vibrio cholerae in the Kathmandu valley, Nepal. During June 2008 to January 2009, 210 diarrheal specimens received at National Public Health Laboratory from suspected cholera patients were subjected to standard bacteriological investigation including biotyping and serotyping. Antimicrobial susceptibility pattern of V. cholerae isolates was determined by Kirby Bauer disc diffusion method following CLSI guidelines. A total of 57 (27%) V. cholerae isolated were recovered, all of which belonged to 01 Ogawa Biotype EL Tor. Based on antibiogram, V. cholerae isolates in our study revealed three distinct R-types: R-type I, R-type II and R-type III. All three R types showed resistance to furazolidone, nalidixic acid and cotrimoxazole while sensitive to ciprofloxacin and tetracycline. Additional resistance to ampicillin and erythromycin was observed respectively in R-type II and III. Different R-types showed unique month wise variations (P < 0.05). Differentiation of V. cholerae strains into R-types is an important tool. In addition to direct patient management, it may have implication in identifying the source and spread of infection, and understanding the distribution pattern in a particular geographical region.

Optical microchip array biosensor for multiplexed detection of bio-hazardous agents.

An optical waveguide array biosensor suitable for rapid detection of multiple bio-hazardous agents is presented. SpectroSens™ optical microchip sensors contain multiple spatially-separated waveguide channels with integral high-precision Bragg gratings sensitive to changes in refractive-index; selective surface-functionalisation of discrete sensing channels with different antibodies as bio-recognition elements enables selective multi-analyte biological detection. Interactions between target antigens in the test sample and respective surface-immobilised antibodies result in localised changes in refractive-index; the biosensor response manifests as increases in wavelength of light reflected from specific sensing channels. Multiplexed, label-free detection of 8 different biological agents, encompassing bacterial spores, vegetative cells, viruses and proteinaceous toxins has been demonstrated in real-time. Selective detection of Bacillus atrophaeus (BG) spores, Escherichia coli cells, MS2 viruses and ovalbumin (OVA) protein (simulant bio-hazardous agents) was first demonstrated as proof-of-concept; subsequently, detection of Bacillus anthracis (BA) spores (UM23CL2 strain), Franciscella tularensis (FT) cells (live vaccine strain), Vaccinia viruses (heat-killed) and ricin toxin (bio-hazardous agents) was proven. Two optical microchip sensors, each comprising 8 sensing channels were packaged into a single disposable cartridge allowing simultaneous 16-channel data acquisition. The specific antibody deposition sequence used in this study enabled detection of either 4 simulants or 4 bio-hazardous agents using a single consumable. The final device, a culmination of the multidisciplinary convergence of the fields of biology, chemistry, optoelectronics and microfluidics, is man-portable and inherently robust. The performance characteristics of the SpectroSens™ technology platform highlight its potential for exploitation as a 'detect to warn/treat' biodetector in security and defence operations.

Bacteriology and antimicrobial susceptibility of adult chronic dacryocystitis.

INTRODUCTION: Chronic dacryocystitis results in chronic infection and inflammation of the lacrimal sac. OBJECTIVE: To identify the aetiology of chronic dacryocystitis and to determine their antimicrobial susceptibility pattern. MATERIALS AND METHODS: A cross - sectional study was undertaken including 120 lacrimal swab materials collected from patients aged above 15 years suffering from chronic dacryocystitis. STATISTICS: Data analysis was done by using software "Win pepi'' ver 7.9. RESULTS: The bacteria of eight different species were isolated from 76.66 % (92/120) culture positive samples. 85.86 % showed a single and 14.13 % showed a mixed growth pattern. Coagulase negative staphylococci were the most common bacteria (P= 0.018) accounting for 33.96 % followed by Staphylococcus aureus (25.46 %), Streptococcus pneumoniae ( 19.81 % ), Streptococci viridans (5.66 %), Escherichia coli (5.66 %), Haemophilus spp ( 4.71 % ), Streptococcus pyogenes (3.77 %) and Bacillus spp (0.94 % ). Staphylococcus aureus were the most predominant bacteria in mixed growth. Rate of infection was higher in males 81.39 % than in females 74.02 %. Infection was higher in the age group of above 31 years. In the antimicrobial susceptibility test, except staphylococcus aureus, all the Gram positive isolates were 100 % sensitive to chloramphenicol and were least sensitive to tobramycin, but Gram negative isolates were equally sensitive to Chloramphenicol and Nalidixic acid. CONCLUSION: Coagulase negative staphylococci are the most frequently isolated bacteria. Staphylococcus aureus is predominantly found in mixed growth. Chloramphenicol is the most effective drug of choice for chronic dacryocystitis.

Label-free monitoring of antibody-antigen interactions using optical microchip biosensors.

A rapid, label-free optical biosensor system for sensitive monitoring of bio-molecular interactions in real-time is presented. SpectroSens sensor chips are based on integrated planar Bragg gratings sensitive to localised changes in refractive index. Bio-molecule recognition is imparted by functionalisation of the sensing surface with antibodies against targets of interest. In this study, antibodies against selected proteins were oriented with recombinant Protein A/G, which was covalently immobilised to the sensor chip via amine coupling to a glutaraldehyde-activated silane layer. Immunoassays for the detection of rabbit IgG and ovalbumin proteins as model antibody-antigen interaction systems were performed. Binding of complementary antigens to respective antibody-functionalised sensors manifested as changes in wavelength of light reflected from the optical sensors. Quantitative binding kinetics with detection sensitivities in the mid ng/ml range were obtained for both antigens using this planar, two-dimensional surface coating. Data presented demonstrate the suitability of SpectroSens sensors as a valuable tool in life science research and development for monitoring bio-specific interactions, protein concentration determination and antibody selection; the optical integration and analytical characteristics of these sensors suggest that they may find numerous applications in bio-pharmaceutical development and clinical diagnostics.

Use of sequential leaching, mineralogy, morphology and multivariate statistical technique for quantifying metal pollution in highly polluted aquatic sediments--a case study: Brahmani and Nandira Rivers, India.

The particle size distribution, geochemical composition and sequential leaching of metals (Fe, Mn, Ni, Cu, Co, Cr, Pb, Zn and Cd) are carried out in core sediments (<88 microm) from the Brahmani and Nandira Rivers, India. To confirm the contamination of downstream sediments by fly ash, mineralogical and morphological characterizations were carried out. High environmental risk of Co, Pb and Ni is due to their higher availability in exchangeable fraction. The metals like Zn, Cu and Mn represent an appreciable portion in the carbonate phase. Metals such as Zn, Pb, Cd, Co and Ni are associated with reducible phase may be due to adsorption. The organic bound Cu, Zn, and Pb seem to be second dominant fraction among non-lithogenous in Nandira sediments. Factor analysis data reveals that textural parameters, Fe-Mn oxy/hydroxides, organic precipitation and coal fly ash disposals, are individually responsible for the enrichment of heavy metals. The relationships among the stations are highlighted by cluster analysis to identify the contamination levels.