Sarita Manandhar - Academia.edu (original) (raw)

Papers by Sarita Manandhar

Vitae

BACKGROUND: Methicillin resistance and biofilm-producing Staphylococci are emerging as multidrug-... more BACKGROUND: Methicillin resistance and biofilm-producing Staphylococci are emerging as multidrug-resistant strains narrowing the efficacy of antimicrobial therapy. Although vancomycin is used as the drug of choice to treat such isolates, different studies worldwide have documented the emergence of strains that are intermediately susceptible or resistant to this antibiotic. OBJECTIVE: The study aimed to determine the minimum inhibitory concentration of vancomycin to methicillin-resistant and biofilm-producing staphylococci isolated from different clinical specimens. METHODS: 375 staphylococci isolated from different clinical specimens over one year were included in the study. Biofilm formation was determined by the Tissue culture plate method (TCP), and ica genes were identified by Polymerase Chain Reaction (PCR). Antibiotic susceptibility and methicillin resistance were done following Clinical and Laboratory Standards Institute (CLSI) guidelines. The minimum inhibitory concentration...

Annals of Clinical Microbiology and Antimicrobials

Background Coagulase-negative staphylococci (CNS) survive as commensals of skin, anterior nares a... more Background Coagulase-negative staphylococci (CNS) survive as commensals of skin, anterior nares and external canals of human and were regarded as non-infectious pathogens. However, they are emerging as a major cause of nosocomial infectious due to their ability to form biofilms and high resistance to several classes of antibiotics. This study examines the biofilm forming abilities of 214 clinical CNS isolates using phenotypic and genotypic methods, and determines their antibiotic susceptibility patterns. Methods A total of 214 clinical isolates collected from different clinical samples were identified as CNS and their antibiotic susceptibility determined by CLSI guidelines. The biofilm forming ability of all isolates was determined by three phenotypic methods; Congo red agar (CRA) method, tube adherence method (TM) and tissue culture plate (TCP) method and by genotypic method for the detection of icaAD genes. Results Among all the isolates, S. epidermidis (57.5%) was found the most ...

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Plant Growth Promoting Rhizobacteria for Sustainable Stress Management, 2019

Inoculation of Azotobacter chroococcum in preparing organic compost by vermicomposting using Eise... more Inoculation of Azotobacter chroococcum in preparing organic compost by vermicomposting using Eisenia fetida (common names: red worm, brandling worm, panfish worm, trout worm, tiger worm, red wiggler worm, red Californian earthworm) can promote the growth of the Phaseolus bean. Various abiotic stresses, such as drought and salinity, are among the major environmental constraints that limit growth, productivity, and quality of plants. The growth promotion of Phaseolus bean with inoculation of A. chroococcum in the presence of vermicompost using different substrate combinations was assessed by a number of nodules, shoot length, root length, dry shoot weight, dry root weight, and nitrogen, phosphorus, and potassium (NPK) content of the plant. Among different substrates used, cow dung only and cow dung plus straw could be enriched with A. chroococcum with survival period up to 5 weeks. However, cow dung plus chopped grass and cow dung plus ground grass couldn't be enriched with A. chroococcum. A significant positive response was noted in all growth parameters when the plant was inoculated with A. chroococcum in the presence of vermicompost compared to the untreated control plants. Cow dung plus straw had been used as a substrate for the enrichment of vermicomposting with A. chroococcum.

Infectious Disease Reports, 2021

Resistance to antibiotics, biofilm formation and the presence of virulence factors play important... more Resistance to antibiotics, biofilm formation and the presence of virulence factors play important roles in increased mortality associated with infection by staphylococci. The macrolide lincosamide streptogramin B (MLSB) family of antibiotics is commonly used to treat infections by methicillin-resistant isolates. Clinical failure of clindamycin therapy has been reported due to multiple mechanisms that confer resistance to MLSB. This study aims to find the incidence of different phenotypes of MLSB resistance and biofilm production among staphylococci. A total of 375 staphylococci were isolated from different clinical samples, received from two tertiary care hospitals in Nepal. Methicillin resistance was detected by cefoxitin disc diffusion method and inducible clindamycin resistance by D test, according to CLSI guidelines. Biofilm formation was detected by the tissue culture plate method and PCR was used to detect ica genes. Of the total staphylococci isolates, 161 (42.9%) were Staphy...

Microbial Diversity in Hotspots, 2022

The overall growth and development of various plants is benefited by the activity of rhizospheric... more The overall growth and development of various plants is benefited by the activity of rhizospheric microorganisms in soil. The beneficial activities of these organisms include biological nitrogen fixation, phosphate solubilization and mineralization etc. which is enhanced in presence of mycorrhiza. A pot culture trial was carried out to study the growth promotion of Oryza sativa with dual inoculation of Azotobacter chroococcum and Piriformospora indica an Arbuscular-Mycorrhiza-like-fungus in presence of vermicompost. The study parameters included to evaluate the dual effect were shoot length, root length, fresh and dry shoot weight, fresh and dry root weight, panicle numbers, plant tissue analysis (NPK content) and soil analysis in terms of pH, NPK and organic content on 45th and 90th day for vegetative and reproductive stage respectively. In both stages, a significant positive response was observed in all growth parameters when plant was dual inoculated with A. chroococcum and P. in...

BMC Microbiology

Background Staphylococcus aureus is a notorious human pathogen that causes often lethal systemic ... more Background Staphylococcus aureus is a notorious human pathogen that causes often lethal systemic conditions that are mostly medical device associated biofilm infections. Similarly, coagulase negative staphylococci are emerging as leading pathogen for nosocomial infections owing to their ability to form biofilm on implanted medical equipment. Chronic in nature, these infections are difficult to treat. Such recalcitrance of these infections is caused mainly due to the presence of persister cells, which exhibit transient yet extreme tolerance to antibiotics. Despite tremendous clinical significance, there is lack of studies on persister cells formation among clinical bacterial isolates. Considering the importance of factors influencing persister formation, in this study, we evaluate the association of antibiotic tolerance with biofilm production, antibiotic stress, growth phase, specimen type, and dependency on staphylococcal species. Biofilm formation was detected among 375 clinical s...

The emergence and spread of antibiotic resistance, as well as the evolution of new strains of dis... more The emergence and spread of antibiotic resistance, as well as the evolution of new strains of disease causing agents, are of great concern to the global health community. Effective treatment of a disease entails the development of new pharmaceuticals or some potential source of novel drugs. Commonly used medicinal plants of our community could be an excellent source of drugs to fight off this problem. This study is focused on exploring the antimicrobial properties of the plants that are commonly being used as traditional medicines. The antimicrobial potential of four different plant extracts was screened against twelve pathogenic microorganisms and two reference bacterial strains. Methanolic extracts of Oxalis corniculata, Artemisia vulgaris, Cinnamomum tamala, and Ageratina adenophora were subjected to a test of their antimicrobial properties by agar well diffusion method. The result indicated that most of the extracts exhibited antimicrobial properties. The highest potential was o...

Background: Biofilm mediated infection by Staphylococci have a significant negative impact on pat... more Background: Biofilm mediated infection by Staphylococci have a significant negative impact on patient health and necessitate reliable method for detecting biofilm producers. The ability of isolates to produce biofilm make them resistant to host immune response as well as available antibiotics. This study aims to detect biofilm producing ability among clinical staphylococci by phenotypic methods and presence of icaAD genes as well as their antibiotic profile. Methods: A total of 4063 different clinical specimen received in the tertiary care hospital of Nepal were examined and Staphylococci were identified following standard microbiological procedure. The antibiotic resistivity pattern was detected by Kirby Bauer disc diffusion method whereas biofilm formation was detected by three phenotypic methods viz. congo red agar (CRA), tube method (TM) and tissue culture plate (TCP) method. Furthermore, icaAD genes were detected by PCR method. Results: A total of 161 Staphylococci were isolate...

Journal of Institute of Science and Technology

Resistance towards fluoroquinolones and treatment failure is a matter of concern in enteric fever... more Resistance towards fluoroquinolones and treatment failure is a matter of concern in enteric fever. The present study was undertaken to analyze the susceptibility pattern of Salmonella towards fluoroquinolones using 2006 and 2013 Clinical Laboratory Standards Institute (CLSI) breakpoint for interpretation and revisit the efficacy of Nalidixic acid resistance (NAR) as a phenotypic marker. A retrospective analysis of the zone of inhibition (ZOI) diameter data and minimum inhibitory concentration (MIC) data of 105 Salmonella was conducted. The ZOI diameter analysis showed that all isolates were susceptible to Ofloxacin and Ciprofloxacin using the previous 2006 ZOI breakpoint. However, with the revised 2013 breakpoint of Ciprofloxacin, the susceptibility percent dropped significantly and for Ofloxacin the breakpoint was not revised, so the percentage remained unchanged. The MIC analysis showed that all isolates were susceptible towards Ofloxacin and 97.14 % of isolates were susceptible...

BMC research notes, Jan 10, 2018

Staphylococcus genus comprising both Staphylococcus aureus and coagulase negative staphylococci (... more Staphylococcus genus comprising both Staphylococcus aureus and coagulase negative staphylococci (CoNS) are widely distributed in nature and can infect diversity of hosts. Indeed, staphylococci are the major pathogens causing biofilm associated infections caused by contaminated hospital indwelling devices. These infections are persistent in nature being highly refractory to various stresses including antibiotics. Implementation of efficient diagnostic techniques for the biofilm production would help minimize the disease burden. Thus, early detection of pathogenic strains producing biofilms warrant the utmost importance in diagnostic laboratories especially in resource limited settings. Among 375 isolates collected from different clinical specimens, 214 (57%) were identified as coagulase negative staphylococci and 161 (43%) S. aureus. Detection of In-vitro biofilm formation in these isolates were carried out by three commonly used phenotypic assays and a genotypic assay. While evaluat...

Frontiers in Microbiology

Staphylococcus aureus, a notorious human pathogen, is a major cause of the community as well as h... more Staphylococcus aureus, a notorious human pathogen, is a major cause of the community as well as healthcare associated infections. It can cause a diversity of recalcitrant infections mainly due to the acquisition of resistance to multiple drugs, its diverse range of virulence factors, and the ability to produce biofilm in indwelling medical devices. Such biofilm associated chronic infections often lead to increase in morbidity and mortality posing a high socioeconomic burden, especially in developing countries. Since biofilm formation and antibiotic resistance function dependent on each other, detection of biofilm expression in clinical isolates would be advantageous in treatment decision. In this premise, we attempt to investigate the biofilm formation and its association with antibiotic resistance in clinical isolates from the patients visiting tertiary health care hospitals in Nepal. Bacterial cells isolated from clinical samples identified as S. aureus were examined for in-vitro biofilm production using both phenotypic and genotypic assays. The S. aureus isolates were also examined for susceptibility patterns of clinically relevant antibiotics as well as inducible clindamycin resistance using standard microbiological techniques and D-test, respectively. Among 161 S. aureus isolates, 131 (81.4%) were methicillin resistant S. aureus (MRSA) and 30 (18.6%) were methicillin sensitive S. aureus (MSSA) strains. Although a majority of MRSA strains (69.6%) showed inducible clindamycin resistance, almost all isolates (97% and 94%) were sensitive toward chloramphenicol and tetracycline, respectively. Detection of in vitro production of biofilm revealed the association of biofilm with methicillin as well as inducible clindamycin resistance among the clinical S. aureus isolates.

Tribhuvan University Journal of Microbiology

Objectives: In order to determine the prevalence of multi-drug resistance along with AmpC and met... more Objectives: In order to determine the prevalence of multi-drug resistance along with AmpC and metallo-β-lactamase producing P. aeruginosa, a six month cross-sectional study was carried out at Shahid Gangalal National Heart Center. Methods: A total of 756 clinical specimens were analyzed for bacteriological profi le. The bacterial isolates were identifi ed by cultural and biochemical techniques. Antibiotic susceptibility testing of the isolates was performed by Kirby-Bauer disc diffusion method. MDR isolates were screened and tested for MBL and AmpC production. Ceftazidime resistant isolates were tested for MBL and Cefoxitin resistant isolates for AmpC. Results: Among all the clinical samples analyzed, P. aeruginosa was detected in 75 samples (9.92%). Antibiotic susceptibility testing showed Imipenem as the most effective drug with susceptibility of 76% followed by Piperacillin-Tazobactam (74.7%) and Piperacillin (41.3%). Out of 75 P. aeruginosa isolates, 53 (70.6%) of them were found to be resistant to at least three out of four anti-pseudomonal agents, thus were considered as MDR. Out of 53 multi-drug resistant P. aeruginosa (MDRPA), all were resistant to ceftazidime whereas 85% (45/53) were resistant to cefoxitin. Out of 53 isolates, 11 (20.75%) showed positive result for MBL. Similarly, 7 out of 45 i.e. 13.2% were found to be AmpC producers. Conclusion: This study signifi ed the high prevalence of MDRPA which is an alarming rate. Also multiple β-lactamase producing P. aeruginosa were detected which can further complicate the treatment options. Regular monitoring of antibiotic susceptibility and rational use of antibiotics would be helpful in eliminating the outbreaks of multiple β-lactamase producing MDRPA.

Asian Journal of Medical Sciences, 2015

Background: Bloodstream infection (BSI) is a signifi cant cause of morbidity and mortality. In Ne... more Background: Bloodstream infection (BSI) is a signifi cant cause of morbidity and mortality. In Nepal, very few studies on BSIs have restricted the understanding of their cause, prevention and treatment. This cross-sectional study was conducted to isolate BSIs causing pathogens and determine their antibiotic susceptibility pattern in patients visiting Kathmandu Model Hospital during December 2012 to May 2013. Materials and Methods: Standard laboratory procedure was used to screen, isolate and identify the bacteria from 1,205 patients. The antibiotic susceptibility pattern (AST) was analyzed by modifi ed Kirby Bauer technique and data were analyzed using SPSS version-16. Results: Out of 1,205 blood samples, 186 (15.4 %) were culture positive. The most common bacteria isolated were: Salmonella spp., Escherichia coli, Klebsiella pneumoniae and CoNS. Gram-negative bacteria were the predominant causes of BSIs. Salmonella Typhi was isolated in 71 % cases of bloodstream infection followed by Salmonella Paratyphi A in 16 %, Escherichia coli in 5.3 % and Klebsiella pneumoniae in 0.5 %. The gram-positive organism responsible for causing BSI was coagulase-negative staphylococcus in 7 % cases. There was no signifi cant association between bacteremia and gender of the patients. During ASTs, Gram-negative bacteria were sensitive to Chloramphenicol with only 0.5 % resistivity. Salmonella Typhi (85.6 % of isolates) showed resistance to Nalidixic acid. Gram-positive bacteria showed 100 % sensitivity towards Chloramphenicol and Gentamicin and were least sensitive to Amoxicillin. Conclusion: Salmonella spp., was major cause of BSIs. Increase in antibiotic resistivity for BSI causing pathogens has necessitated continuous monitoring of the susceptibility of organisms towards antibiotics.

Medical Journal of Shree Birendra Hospital, 2015

Introduction: Amp C β lactamases confer resistance to a wide variety of β-lactam antibiotics and ... more Introduction: Amp C β lactamases confer resistance to a wide variety of β-lactam antibiotics and are poorly inhibited by β-lactamase inhibitors such as clavulanic acid. Plasmid carrying Amp C enzyme also carry genes responsible of resistance to multiple other antibiotics, hence therapeutic options to infection caused by this type of organism is limited. Limited studies on prevalence of these organisms have been done in Nepal. The study is done to know the prevalence of Amp C β lactamase producers among the uropathogens. Methods: Amp C β lactamase producers were detected by double disc synergy test using the disc of cefoxitin (30μg) and cefoxitn (30μg) plus phenylboronic acid (20μl). An increase in zone diameter of ≥5mm to cefoxitin disc with phenylboronic acid versus cefoxitin alone was considered confirmed ABL producers. Result: The ABL production was found in 8.94% of the total isolates. It was observed in 9.87% of E. coli isolates and in 20% of Ps. aeruginosa. ABL producers were ...

Journal of Nepal Health Research Council

Background: Staphylococci are posing threat due to increasing trend of antimicrobial resistance p... more Background: Staphylococci are posing threat due to increasing trend of antimicrobial resistance particularly methicillin. Macrolide lincosamide streptogramin B (MLSB) family of antibiotics is commonly used to treat such infections. This study was aimed to determine the prevalence of inducible clindamycin resistance and observation of erm and msr genes among Staphylococci isolated from tertiary care hospital of Nepal during July 2017 to March 2018.Methods: Staphylococci from different clinical specimens were identified and antibiotic susceptibility profile was assessed following Kirby Bauer disc diffusion method. The double disc diffusion or D-zone test as outlined in CLSI document M100-S24 was performed to examine inducible clindamycin resistant isolates. Multiplex PCR was performed for detection of erm and msr gene in isolates using specific primers for ermA, ermB, ermC, msrA and msrB genes.Results: Of the 60 Staphylococci isolates, 39 (65%) were S. aureus and 21 (35%) were coagula...