Diagnostic evaluation of IgM ELISA and IgM Immunofluorescence assay for the diagnosis of Acute Scrub Typhus in central Nepal.

BACKGROUND: Scrub typhus is an acute febrile illness caused by the obligate intracellular bacterium, Orientia tsutsugamushi. Immunochromatography (ICT) and IgM ELISA are two of the routinely employed antibody based assays for diagnosis of Scrub typhus fever in Nepal, although the recommended gold standard diagnostic test is IgM Immunofluorescence assay (IFA). This study evaluated InBios Scrub Typhus Detect™ Immunoglobulin M (IgM) ELISA and IgM Immunofluorescence assays in single serum sample at the time of admission. METHOD: Study participants (1585 suspected cases), were enrolled based on acute febrile illness with suspected scrub typhus cases in central Nepal. Blood sample was collected from the suspected patients of scrub typhus, presenting with acute febrile illness. IgM antibody to Orientia tsusugamushi was detected by using Scrub Typhus Detect™ Kit and an in-house IgM IFA. The IFA assay was performed with the Gilliam, Karp, Kato strains and O. chuto antigens following the ARRL protocol. RESULT: Statistical analysis of IgM ELISA results when compared to reference test, IgM IFA results demonstrated the following characteristics, sensitivity 84.0% (95%CI: 79.73-87.68%), specificity 94.82% (95% CI: 93.43-95.99%), positive likelihood ratio 16.21% (95% CI: 12.71-20.67%), negative likelihood ratio 0.17% (95% CI: 0.13-0.21%), disease prevalence 22.08% (95% CI: 20.06 -24.21%), positive predictive value 82.12% (95% CI: 78.28-85.42%) and negative predictive value 95.44% (95% CI: 94.27-96.38%) respectively. CONCLUSION: Although IgM IFA is considered the gold standard test for the diagnosis of scrub typhus cases, it is relatively expensive, requires trained personal and a microscope with fluorescence filters. Scrub typhus IgM ELISA may be the best alternative test and possible viable option for resource limited endemic countries like Nepal.

Controlling Proton and Electron Transfer Rates to Enhance the Activity of an Oxygen Reduction Electrocatalyst.

An electrochemical approach is developed that allows for the control of both proton and electron transfer rates in the O2 reduction reaction (ORR). A dinuclear Cu ORR catalyst was prepared that can be covalently attached to thiol-based self-assembled monolayers (SAMs) on Au electrodes using azide-alkyne click chemistry. Using this architecture, the electron transfer rate to the catalyst is modulated by changing the length of the SAM, and the proton transfer rate to the catalyst is controlled with an appended lipid membrane modified with proton carriers. By tuning the relative rates of proton and electron transfer, the current density of the lipid-covered catalyst is enhanced without altering its core molecular structure. This electrochemical platform will help identify optimal thermodynamic and kinetic parameters for ORR catalysts and catalysts of other reactions that involve the transfer of both protons and electrons.

Threat of drug resistant Staphylococcus aureus to health in Nepal.

BACKGROUND: Staphylococcus aureus is the most commonly isolated organism from the different clinical samples in hospital. The emergence and dissemination of methicillin resistant Staphylococcus aureus (MRSA) and growing resistance to non-beta-lactam antibiotics is making treatment of infections due to this organism increasingly difficult. METHODS: This study was conducted to determine the frequency of Staphylococcus aureus isolated from different clinical samples, rates of MRSA and full antibiotic susceptibility profiles. Clinical samples were cultured and Staphylococcus aureus was identified using standard microbiological methods recommended by the American Society for Microbiology (ASM). Methicillin resistance was confirmed using cefoxitin and oxacillin disks. Inducible clindamycin resistance was identified using D-zone test. RESULTS: From the processed samples, 306 isolates of Staphylococcus aureus were recovered. All the isolates were susceptible to vancomycin and teicoplanin. Methicillin resistance was observed in 43.1% of isolates while inducible clindamycin resistance in 12.4% of the isolates. CONCLUSIONS: The results of our study reveals that rates of resistance to commonly prescribed antibiotics in Staphylococcus aureus clinical isolates is high. In particular, rate of methicillin resistance is alarming, prompting concern on the rational use of antibiotics and vigilant laboratory-based surveillance of resistance rates in Nepal.

Gender preference and fertility behavior among married women: A community based study from far western Nepal.

Gender preference often results in low use of contraceptives and parity progression, which can increase the risks of morbidity and mortality for women. This study aimed to identify gender preference and fertility behavior, including contraceptive use and the desire for additional children, among married women. A cross-sectional descriptive study was conducted using systematic random sampling to select280 household, with one respondent interviewed from each household using a semi-structured interview schedule. Descriptive and inferential statistical analysis were performed on the collected data. Of 280 respondents, 44.6% were aged 26-35 years (mean30.23±7.39 years). Most (74.3%) were literate, and 70% were paid worker. Son preference was reported by 53%, with support in old age (87.2%) being the main reason. Gender preference was 60.5% less likely among Bramhin/Chhetri ethnic groups (p = 0.033) and 71.3% less likely if husbands were literate (p = 0.002). Contraception use was 90.7%, but 31.8% desired additional children. Permanent contraceptive method use was 9.387 times more likely above age 30 years (p = <0.001), independent of respondents' and husbands' education, sex composition of children, and having a preferred child. Desire for more children was 6.813 times more likely below age 30 years (p = <0.001) and 5.875 times more likely with 1-2 living children (p = 0.001), independent of respondents' and husbands education.The study concludes that son preference persisted among the illiterate. Contraceptive use was lower among respondents below 30 years. Enhancing educational status may reduce gender bias. Targeting family planning to women below 30 years could improve contraceptive utilization in this age group.

Hybrid bilayer membranes as platforms for biomimicry and catalysis.

Hybrid bilayer membrane (HBM) platforms represent an emerging nanoscale bio-inspired interface that has broad implications in energy catalysis and smart molecular devices. An HBM contains multiple modular components that include an underlying inorganic surface with a biological layer appended on top. The inorganic interface serves as a support with robust mechanical properties that can also be decorated with functional moieties, sensing units and catalytic active sites. The biological layer contains lipids and membrane-bound entities that facilitate or alter the activity and selectivity of the embedded functional motifs. With their structural complexity and functional flexibility, HBMs have been demonstrated to enhance catalytic turnover frequency and regulate product selectivity of the O2 and CO2 reduction reactions, which have applications in fuel cells and electrolysers. HBMs can also steer the mechanistic pathways of proton-coupled electron transfer (PCET) reactions of quinones and metal complexes by tuning electron and proton delivery rates. Beyond energy catalysis, HBMs have been equipped with enzyme mimics and membrane-bound redox agents to recapitulate natural energy transport chains. With channels and carriers incorporated, HBM sensors can quantify transmembrane events. This Review serves to summarize the major accomplishments achieved using HBMs in the past decade.

Scrub Typhus and Molecular Characterization of Orientia tsutsugamushi from Central Nepal.

Scrub typhus is a vector-borne, acute febrile illness caused by Orientia tsutsugamushi. Scrub typhus continues to be an important but neglected tropical disease in Nepal. Information on this pathogen in Nepal is limited to serological surveys with little information available on molecular methods to detect O. tsutsugamushi. Limited information exists on the genetic diversity of this pathogen. A total of 282 blood samples were obtained from patients with suspected scrub typhus from central Nepal and 84 (30%) were positive for O. tsutsugamushi by 16S rRNA qPCR. Positive samples were further subjected to 56 kDa and 47 kDa molecular typing and molecularly compared to other O. tsutsugamushi strains. Phylogenetic analysis revealed that Nepalese O. tsutsugamushi strains largely cluster together and cluster away from other O. tsutsugamushi strains from Asia and elsewhere. One exception was the sample of Nepal_1, with its partial 56 kDa sequence clustering more closely with non-Nepalese O. tsutsugamushi 56 kDa sequences, potentially indicating that homologous recombination may influence the genetic diversity of strains in this region. Knowledge on the circulating strains in Nepal is important to the development of diagnostic tests and vaccines to support public health measures to control scrub typhus in this country.

Hybrid Dynamic Windows with Color Neutrality and Fast Switching Using Reversible Metal Electrodeposition and Cobalt Hexacyanoferrate Electrochromism.

Dynamic windows, which electronically switch between clear and dark states on demand, save energy in buildings and automobiles by minimizing the lighting, heating, and cooling costs. In this study, we design dynamic windows by combining reversible metal electrodeposition (RME) and electrochromism, two promising approaches for optoelectronics. These hybrid dynamic windows tint on both electrodes. Reversible Bi and Cu electrodeposition is elicited on the working electrode, while an electrochromic cobalt hexacyanoferrate thin film darkens on the counter electrode. By facilitating plane parallel ion diffusion and dual tinting, this architecture enables dynamic windows to switch more rapidly than devices based on traditional RME schemes. We demonstrate that 25 cm2 devices switch with 58% optical contrast between a transparent and a color-neutral dark state in 20 s. Moreover, these hybrid dynamic windows switch 1000 times without significant degradation in optical performance.

Nanostructured Ni-Cu Electrocatalysts for the Oxygen Evolution Reaction.

Ni-based materials are promising electrocatalysts for the oxygen evolution reaction (OER) for water splitting in alkaline media. We report the synthesis and OER electrocatalysis of both Ni-Cu nanoparticles (20-50 nm in diameter) and Ni-Cu nanoclusters (<20 metal atoms). Analysis of mass spectral data from matrix-assisted laser desorption/ionization and electrospray ionization techniques demonstrates that discrete heterobimetallic Ni-Cu nanoclusters capped with glutathione ligands were successfully synthesized. Ni-Cu nanoclusters with a 52:48 mol % Ni:Cu metal composition display an OER onset overpotential of 50 mV and an overpotential of 150 mV at 10 mA cm-2, which makes this catalyst one of the most efficient nonprecious metal OER catalysts. The durability of the nanocluster catalysts on carbon electrodes can be extended by appending them to electrodes modified with TiO2 nanoparticles. Infrared spectroscopy results indicate that the aggregation dynamics of the glutathione ligands change during catalysis. Taken together, these results help explain the reactivity of a novel class of nanostructured Ni-Cu OER catalysts, which are underexplored alternatives to more commonly studied Ni-Fe, Ni-Co, and Ni-Mn materials.

Epidemiology, Risk Factors and Seasonal Variation of Scrub Typhus Fever in Central Nepal.

Orientia. tsutsugamushi, a zoonotic bacterial infection common in the region known as the tsutsugamushi triangle. This study aims to determine the seroprevalence, seasonal variation, and risk factors of scrub typhus among the acute febrile illness patients attending different hospitals of central Nepal. Blood samples were collected from hospitalized patients of acute febrile illness suspected of scrub typhus infection attending different hospitals of central Nepal from April 2017 to March 2018. The IgM antibody to Orientia tsutsugamushi was detected by using the Scrub Typhus Detect™ Kit. Among the total cases (1585), 358 (22.58%) were positive for IgM Antibodies. Multivariate analysis identified several risks factors to be significantly associated with the scrub typhus infection, including gender (female) (odds ratio [OR] = 1.976, p ≤ 0.001, confidence interval [CI] = 1.417⁻2.756), rural residential location (odds ratio [OR] = 0.431, p = 0.001, confidence interval [CI] = 0.260⁻0.715), house near grassland (odds ratio [OR] = 3.288, p ≤ 0.001, confidence interval [CI] = 1.935⁻5.587), and working in the field (odds ratio [OR] = 9.764, p = 0.004, confidence interval [CI] = 2.059⁻46.315). The study findings indicate scrub typhus infection to be a significant health problem in Nepal. The proper diagnosis of infection cases, timely institution of therapy, public awareness, and vector control are important measures to be taken for the prevention and management of scrub typhus.

Burden of bacterial upper respiratory tract pathogens in school children of Nepal.

INTRODUCTION: Respiratory tract infections are one of the most common human infections in all age group and important cause of mortality and morbidity worldwide. Most bacterial upper respiratory tract infections are vaccine preventable. This study aimed to determine the prevalence of carrier state of bacterial upper respiratory tract pathogens among school children. It also aimed to study their antibiograms. METHODS: The specimen from posterior pharyngeal wall and tonsils were collected from 204 participants on calcium alginate coated swabs (HiMedia). Isolates were identified by standard microbiological methods and tested for in vitro antibiotic susceptibility testing by modified Kirby-Bauer disc diffusion method. RESULTS: In this study, Streptococcus pneumoniae (16.6%) was the most common bacterial pathogen recovered, followed by Staphylococcus aureus (14.7%), ß-haemolytic streptococci (non-Group A) (8.8%), Streptococcus pyogenes (5.3%) and Corynebacterium diphtheriae (3.4%). The Gram negative bacteria were Klebsiella pneumoniae (4.9%), Haemophilus influenzae (3.4%) and Neisseria meningitidis (1.4%). Important findings in antibiogram include high resistance of Streptococcus pneumoniae to penicillin (91.17%) and resistance of S. aureus to oxacillin (23.3%). CONCLUSION: Pharyngeal colonisation by S. pneumoniae was found high among school children and this calls for an urgent need to include pneumococcal vaccine in routine national immunisation schedule of Nepal given the high burden of invasive pneumococcal disease. Despite expected universal vaccination, pharyngeal colonisation by C. diphtheriae is possible and there is possibility of transmission of these respiratory pathogens to other healthy children.

Risk factors assessment for nasal colonization of Staphylococcus aureus and its methicillin resistant strains among pre-clinical medical students of Nepal.

BACKGROUND: Staphylococcus aureus (S. aureus), a normal flora of nasal cavity, can cause minor to life threatening invasive diseases and nosocomial infections. Methicillin resistant strains of S. aureus are causing a great challenge for treatment options. Therefore, the purpose of this study was to assess the nasal carriage rate of S. aureus, its methicillin resistant strains and risk factors in medical students prior to clinical exposure. METHODS: The bacterial growth of S. aureus from nasal swab culture was identified by using standard microbiological methods recommended by American Society for Microbiology. Modified Kirby-Bauer disk diffusion method was used for antibiotic susceptibility testing and methicillin resistance was confirmed using cefoxitin and oxacillin disks. D-zone test method was used to determine the inducible clindamycin resistance. RESULTS: Among 200 participants, nasal carriage of S. aureus was detected from 30 (15%) subjects. Upper respiratory tract infections significantly (P < 0.05) contributed the carriage of S. aureus and their methicillin resistant strains. All of the isolates were reported to be susceptible to vancomycin and teicoplanin. S. aureus strains detected from 8 (4%) students were confirmed to be methicillin resistant. CONCLUSIONS: The result of our study demands for strict policy to screen all the students for nasal carriage of S. aureus and its MRSA strains to minimize the transmission of this organism from community to hospital settings.

Growing Menace of Antibacterial Resistance in Clinical Isolates of Pseudomonas aeruginosa in Nepal: An Insight of Beta-Lactamase Production.

Introduction. Pseudomonas aeruginosa is the most frequently isolated organism as it acts as the opportunistic pathogen and can cause infections in immunosuppressed patients. The production of different types of beta-lactamases renders this organism resistant to many commonly used antimicrobials. Therefore, the aim of this study was to document the antibiotic resistance rate in Pseudomonas aeruginosa isolated from different clinical specimens. Methods. Pseudomonas aeruginosa recovered was identified by standard microbiological methods. Antibiotic susceptibility testing was performed by modified Kirby-Bauer disc diffusion method following Clinical and Laboratory Standard Institute (CLSI) guidelines and all the suspected isolates were tested for the production of ESBLs, MBLs, and AmpC. Results. Out of total (178) isolates, 83.1% were recovered from the inpatient department (IPD). Majority of the isolates mediated resistance towards the beta-lactam antibiotics, while nearly half of the isolates were resistant to ciprofloxacin. Most of the aminoglycosides used showed resistance rate up to 75% but amikacin proved to be better option. No resistance to polymyxin was observed. ESBLs, MBLs, and AmpC mediated resistance was seen in 33.1%, 30.9%, and 15.7% isolates, respectively. Conclusions. Antibiotic resistance rate and beta-lactamase mediated resistance were high. Thus, regular surveillance of drug resistance is of utmost importance.

Helicobacter pylori colonization in Nepal; assessment of prevalence and potential risk factors in a hospital-based patient cohort.

BACKGROUND: Helicobacter pylori, a gram-negative bacterium, can cause gastritis, peptic and duodenal ulcers. It is considered an important public health problem for both developed and developing world. This bacterium is classified as the class 1 carcinogen because it can cause cancer. METHODS: A hospital based study was conducted at Chitwan Medical College Teaching Hospital (CMCTH) from May to October 2014. Stool samples were collected from the suspected patients and were subjected to detection of the H. pylori stool antigen (HpSAg) following the procedures recommended by the manufacturer. A standard questionnaire on the potential risk factors was also designed and completed. RESULT: HpSAg was detected in 16 % of suspected patients. The children up to 10 years of age were found to be highly infected (36 %). The patients living in urban area were found more susceptible to develop H. pylori infection (P < 0.05). Tea drinking and repeated eating habit (more than twice a day) were listed as the important factors that can limit the H. pylori infections significantly (P < 0.05). CONCLUSION: In this hospital based study, a significant rate of prevalence was evaluated. However, we recommend a community based extensive study to reveal the real scenario of H. pylori infection in Nepalese populations.

Neonatal Septicemia in Nepal: Early-Onset versus Late-Onset.

Introduction. Neonatal septicemia is defined as infection in the first 28 days of life. Early-onset neonatal septicemia and late-onset neonatal septicemia are defined as illnesses appearing from birth to three days and from four to twenty-eight days postnatally, respectively. Methods. In this cross-sectional study, blood samples from the suspected infants were collected and processed in the bacteriology laboratory. The growth was identified by standard microbiological protocol and the antibiotic sensitivity testing was carried out by modified Kirby-Bauer disk diffusion method. Results. Among total suspected cases, the septicemia was confirmed in 116 (12.6%) neonates. Early-onset septicemia (EOS) was observed in 82 infants and late-onset septicemia (LOS) in 34 infants. Coagulase-negative staphylococcus (CoNS) (46.6%) was the predominant Gram-positive organism isolated from EOS as well as from LOS cases followed by Staphylococcus aureus (14.6%). Acinetobacter species (9.5%) was the predominant Gram-negative organism followed by Klebsiella pneumoniae (7.7%). Conclusions. The result of our study reveals that the CoNS, Staphylococcus aureus, Acinetobacter spp., and Klebsiella pneumoniae are the most common etiological agents of neonatal septicemia. In particular, since rate of CoNS causing sepsis is alarming, prompting concern to curb the excess burden of CoNS infection is necessary.

Community acquired multi-drug resistant clinical isolates of Escherichia coli in a tertiary care center of Nepal.

BACKGROUND: Multi-drug resistance (MDR) in Gram-negative organisms is an alarming problem in the world. MDR and extensively-drug resistance (XDR) is in increasing trend due to the production of different types of beta (ß)-lactamases. Thus the aim of this study was to document the incidence of MDR and XDR in clinical isolates of Escherichia coli and also to find out the enzymatic mechanisms of ß-lactam antibiotics resistance. METHODS: Two hundred clinical isolates of Escherichia coli (E. coli) identified by standard laboratory methods were studied. Antibiotic susceptibility profile was performed for all the isolates and the suspected isolates were phenotypically tested for the production of extended spectrum ß-lactamase (ESBL), metallo ß-lactamase (MBL) and AmpC ß-lactamase (AmpC) by recommended methods. RESULTS: Around three-fourth (78%) of the total isolates were multi-drug resistant. ESBL, MBL and AmpC production was found in 24%, 15% and 9% of isolates respectively. Amikacin, chloramphenicol and colistin were found to be the most effective antibiotics. CONCLUSIONS: High percentage of MDR was observed. ß-lactamase mediated resistance was also high. Thus, regular surveillance of drug resistance due to ß-lactamases production and infection control policy are of utmost importance to minimize the spread of resistant strains.

Chromobacterium violaceum Isolated from a Wound Sepsis: A Case Study from Nepal.

Chromobacterium violaceum is a facultative anaerobic, Gram-negative rod, prevalent in tropical and subtropical regions. It enters through the skin injury and is capable of causing severe systemic infections leading to septic shock and multiorgan failure. It has been reported by few authors across the world but this is probably the first case of Chromobacterium violaceum isolated from wound sepsis from Nepal. In this study, a pus sample from the infection of a prick injury in the left middle finger was collected from the patient admitted to the intensive care unit. Bacteriological investigations of the pus sample revealed the causative organism to be Chromobacterium violaceum. This case study indicates that Chromobacterium violaceum can act as a potential cause of wound sepsis that may lead to the septic shock and if not treated timely, the mortality rate can be high as was in this study. Although this organism is very rare, the infection caused requires prompt treatment to minimize the mortality rate. Therefore, we recommend the timely diagnosis and antimicrobial therapy of this infection to combat the consequences led.

Childhood septicemia in Nepal: documenting the bacterial etiology and its susceptibility to antibiotics.

Introduction. Children are among the most vulnerable population groups to contract illnesses. The varying microbiological pattern of septicemia warrants the need for an ongoing review of the causative organisms and their antimicrobial susceptibility pattern. Therefore, the objective of this study was to document the bacterial etiology of childhood septicemia and its antibiotic susceptibility profile. Methods. Cross-sectional type of study in 1630 suspected patients was conducted at CMCTH from January 2012 to December 2013. Blood samples were collected aseptically for culture. The organisms grown were identified by standard microbiological methods recommended by American Society for Microbiology (ASM) and subjected to antibiotic susceptibility testing by modified Kirby-Bauer disk diffusion method. Methicillin resistance was confirmed using cefoxitin and oxacillin disks methods. Results. Septicemia was detected in 172 (10.6%) cases. Among Gram-positive organisms, coagulase negative staphylococci (CoNS) were leading pathogen and Acinetobacter spp. were leading pathogen among Gram-negative isolates. Vancomycin, teicoplanin, and clindamycin were the most effective antibiotics against Gram-positive isolates while amikacin was effective against Gram-positive as well as Gram-negative isolates. Methicillin resistance was detected in 44.4% of Staphylococcus aureus. Conclusions. This study has highlighted the burden of bacterial etiology for septicemia among children in a tertiary care center of central Nepal.