Prevalence of drug resistant Enterobacteriaceae in a Nepalese tertiary care hospital

Antimicrobial resistance in Enterobacteriaceae is an emerging global public health problem. Numerous studies have reported community-acquired AmpC beta-lactamase and extended spectrum beta-lactamase (ESBL) producing Enterobacteriaceae in Nepal. However, there are limited data on community-acquired Metallo-beta-lactamase (MBL) producing Enterobacteriaceae. A hospital-based descriptive cross-sectional study was conducted using 294 Enterobacteriaceae isolates from a total of 2,345 different clinical specimens collected from patients attending a tertiary care hospital in Nepal. Bacteria were isolated using standard microbiological growth media and identified using biochemical tests. For antimicrobial susceptibility testing, Kirby-Bauer disc diffusion technique was used. AmpC, ESBL, and MBL productions were detected by using combined disc method. AmpC, ESBL, and MBL productions were detected in 19.4%, 29.6%, and 8.5% of total Enterobacteriaceae isolates respectively. Higher rates of beta-lactamases production were seen among the isolates from in-patients in comparison with those from out-patients. However, 11.6%, 25%, and 3.7% of the total isolates from out-patients were AmpC, ESBL, and MBL producers respectively. The co-production of the beta-lactamases was also detected, with two Klebsiella pneumoniae isolates producing all three beta-lactamases. One MBL producing Proteus vulgaris isolate that was pan-resistant with no remaining treatment options was also isolated. Prevalence of drug resistant Enterobacteriaceae in our study was very high. Detection of AmpC, ESBL, and MBL positive isolates from out-patients, who did not have recent history of hospital visit, indicated the community dissemination of the drug resistant bacteria. This is a matter of great concern and an immediate attention to formulate strategies to prevent further development and spread of antibiotic resistance is required.

Detection of NDM Variants (bla NDM-1, bla NDM-2, bla NDM-3) from Carbapenem-Resistant Escherichia coli and Klebsiella pneumoniae: First Report from Nepal

Background

Increasing burden of carbapenem resistance among Enterobacterales is attributable to their ability to produce carbapenemase enzymes like metallo-beta-lactamase (MBL), Klebsiella pneumoniae carbapenemase (KPC), and OXA-type. This study aimed to determine the prevalence of carbapenemases and MBL genes ((bla_NDM-1,bla_NDM-1 and bla_NDM-3) among E. coli and K. pneumoniae isolates.

Methods

A total of 2474 urine samples collected during the study period (July–December 2017) were processed at the microbiology laboratory of Kathmandu Model Hospital, Kathmandu. Isolates of E. coli and K. pneumoniae were processed for antimicrobial susceptibility testing (AST) by disc diffusion method. Carbapenem-resistant isolates were subjected to Modified Hodge Test (MHT) for phenotypic confirmation, and inhibitor-based combined disc tests for the differentiation of carbapenemase (MBL and KPC). MBL-producing isolates were screened for NDM genes by polymerase chain reaction (PCR).

Results

Of the total urine samples processed, 19.5% (483/2474) showed the bacterial growth. E. coli (72.6%; 351/483) was the predominant isolate followed by K. pneumoniae (12.6%; 61/483). In AST, 4.4% (18/412) isolates of E. coli (15/351) and K. pneumonia (3/61) showed resistance towards carbapenems, while 1.7% (7/412) of the isolates was confirmed as carbapenem-resistant in MHT. In this study, all (3/3) the isolates of K. pneumoniae were KPC-producers, whereas 66.7% (10/15), 20% (3/15) and 13.3% (2/15) of the E. coli isolates were MBL, KPC and MBL/KPC (both)-producers, respectively. In PCR assay, 80% (8/10), 90% (9/10) and 100% (10/10) of the isolates were positive for bla_NDM-1, bla_NDM-2 and bla_NDM-3, respectively.

Conclusion

Presence of NDM genes among carbapenemase-producing isolates is indicative of potential spread of drug-resistant variants. This study recommends the implementation of molecular diagnostic facilities in clinical settings for proper infection control, which can optimize the treatment therapies, and curb the emergence and spread of drug-resistant pathogens.

Antibiotic Resistance, Biofilm Formation and Detection of mexA/mexB Efflux-Pump Genes Among Clinical Isolates of Pseudomonas aeruginosa in a Tertiary Care Hospital, Nepal

Efflux-pump system and biofilm formation are two important mechanisms Pseudomonas aeruginosa deploys to escape the effects of antibiotics. The current study was undertaken from September 2019 to March 2020 at a tertiary-care hospital in Kathmandu in order to ascertain the burden of P. aeruginosa in clinical specimens, examine their biofilm-forming ability and determine their antibiotic susceptibility pattern along with the possession of two efflux-pump genes-mexA and mexB. Altogether 2820 clinical specimens were collected aseptically from the patients attending the hospital and processed according to standard microbiological procedures. Identification of P. aeruginosa was done by Gram stain microscopy and an array of biochemical tests. All the P. aeruginosa isolates were subjected to in vitro antibiotic susceptibility testing and their biofilm-forming ability was also examined. Presence of mexA and mexB efflux-pump genes was analyzed by Polymerase Chain Reaction (PCR) using specific primers. Out of 603 culture positive isolates, 31 (5.14%) were found to be P. aeruginosa, of which 55% were multi-drug resistant (MDR). Out of 13 commonly used antibiotics tested by Kirby-Bauer disc diffusion method, greatest resistance was shown against piperacillin-tazobactam 15 (48.4%) and ceftazidime 15 (48.4%), and least against meropenem 6 (19.4%) and ofloxacin 5 (16.2%). Of all 17 MDR isolates subjected to biofilm detection, strong biofilm formation was exhibited by 11 (65%) and 14 (82%) isolates with microtiter plate method and tube method respectively. Out of 17 isolates tested, 12 (70.6%) isolates possessed mexA and mexB genes indicating the presence of active efflux-pump system. Higher number of the isolates recovered from sputum 7 (58.3%) and pus 5 (41.7%) possessed mexA/mexB genes while the genes were not detected at all in the isolates recovered from the urine (p<0.05). This study assessed no significant association between biofilm production and multi-drug resistance (p>0.05). Adoption of stern measures by the concerned authorities to curb the incidence of multi-drug resistant and biofilm-forming isolates is recommended to prevent their dissemination in the hospital settings.

Higher Prevalence of Extended Spectrum β-Lactamase Producing Uropathogenic Escherichia coli Among Patients with Diabetes from a Tertiary Care Hospital of Kathmandu, Nepal

This study aimed to determine the occurrence of antibiotic resistance genes for β-lactamases; blaTEM and blaCTX-M in uropathogenic Escherichia coli isolates from urinary tract infection (UTI) suspected diabetic and nondiabetic patients. A hospital-based cross-sectional study was conducted in Kathmandu Model Hospital, Kathmandu, in association with the Department of Microbiology, GoldenGate International College, Kathmandu, Nepal, from June to December 2018. A total of 1,267 nonduplicate midstream urine specimens were obtained and processed immediately for isolation of uropathogens. The isolates were subjected to antibiotic susceptibility testing and extended spectrum β-lactamase (ESBL) confirmation. In addition, blaTEM and blaCTX-M genes were detected using specific primers. The overall prevalence of UTI was 17.2% (218/1,267), of which patients with diabetes were significantly more infected; 32.3% (31/96) as compared with nonpatients with diabetes, 15.9% (187/1,171). A total of 221 bacterial isolates were obtained from 218 culture-positive specimens in which E. coli was the most predominant; 67.9% (150/221). Forty-four percent (66/150) of the total E. coli was multidrug resistant and 37.3% (56/150) were ESBL producers. Among 56 isolates, 92.3% (12/13) were from patients with diabetes, and 83.0% (44/53) were from nondiabetics. Furthermore, 84.9% of the screened ESBL producers were confirmed to possess either single or both of blaTEM and blaCTX-M genes. The blaTEM and blaCTX-M genes were detected in 53.6% and 87.5% of the phenotypically ESBL confirmed E. coli, respectively. Higher rates of ESBL producing uropathogenic E. coli are associated among patients with diabetes causing an alarming situation for disease management. However, second-line drugs with broad antimicrobial properties are still found to be effective drugs for multidrug resistance strains.

Antimicrobial Susceptibility Pattern of Salmonella spp. Isolated from Enteric Fever Patients in Nepal

INTRODUCTION

Enteric fever, a systemic infection caused by Salmonella enterica Typhi and S. enterica Paratyphi is one of the most common infections in developing countries such as Nepal. Aside from irrational practices of antibiotic use, mutations in chromosomal genes encoding DNA gyrase and Topoisomerase IV and by plasmid mediated quinolone resistant (PMQR) genes are suggested mechanisms for the development of resistance to nalidixic acid and reduced susceptibility to ciprofloxacin. Regardless of high endemicity of enteric fever in Nepal, there is paucity of studies on prevalence and drug-resistance of the pathogen. Therefore, this study aimed to assess the antibiotic susceptibility pattern of Salmonella isolates and determine the minimum inhibitory concentration of ciprofloxacin.

METHODS

A total of 1298 blood samples were obtained from patients with suspected enteric fever, attending Sukraraj Tropical and Infectious Disease Hospital (STIDH) during March-August, 2019. Blood samples were inoculated immediately into BACTEC culture bottles and further processed for isolation and identification of Salmonella Typhi and S. Paratyphi. Axenic cultures of the isolates were further subjected to antimicrobial susceptibility testing (AST) by using the modified Kirby-Bauer disc diffusion method based on the guidelines by CLSI. The minimum inhibitory concentration (MIC) of ciprofloxacin was determined by agar-dilution method.

RESULTS

Out of 1298 blood cultures, 40 (3.1%) were positive for Salmonella spp. among which 29 (72.5%) isolates were S. Typhi and 11 (27.5%) isolates were S. Paratyphi A. In AST, 12.5% (5/40), 15% (6/40) and 20% (8/40) of the Salmonella isolates were susceptible to nalidixic acid, ofloxacin and levofloxacin, respectively, whereas none of the isolates were susceptible to ciprofloxacin. The MIC value for ciprofloxacin ranged from 0.06-16 µg/mL in which, respectively, 5% (2/40) and 52.5% (21/40) of the isolates were susceptible and resistant to ciprofloxacin. None of the isolates showed multidrug-resistance (MDR) in this study.

CONCLUSION

This study showed high prevalence of quinolone-resistant Salmonella spp., while there was marked re-emergence of susceptibilities to traditional first option drugs. Hence, conventional first-line-drugs and third-generation cephalosporins may find potential usage as the empirical drugs for enteric fever. Although our reporting was free of MDR strains, extensive surveillance, augmentation of diagnostic facilities and treatment protocol aided by AST report are recommended for addressing the escalating drug-resistance in the country.

Epidemiology of dengue virus infections in Nepal, 2006-2019

BACKGROUND

Dengue is one of the newest emerging diseases in Nepal with increasing burden and geographic spread over the years. The main objective of this study was to explore the epidemiological patterns of dengue since its first outbreak (2006) to 2019 in Nepal.

METHODS

This study is a retrospective analysis that covers the last 14 years (2006-2019) of reported dengue cases from Epidemiology Diseases Control Division (EDCD), Ministry of Health and Population, Government of Nepal. Reported cases were plotted over time and maps of reported case incidence were generated (from 2016 through 2019). An ecological analysis of environmental predictors of case incidence was conducted using negative binomial regression.

RESULTS

While endemic dengue has been reported in Nepal since 2006, the case load has increased over time and in 2019 a total of 17 992 dengue cases were reported from 68 districts (from all seven provinces). Compared to the case incidence in 2016, incidence was approximately five times higher in 2018 [incidence rate ratio (IRR): 4.8; 95% confidence interval (CI) 1.5-15.3] and over 140 times higher in 2019 (IRR: 141.6; 95% CI 45.8-438.4). A one standard deviation increase in elevation was associated with a 90% decrease in reported case incidence (IRR: 0.10; 95% CI 0.01-0.20). However, the association between elevation and reported cases varied across the years. In 2018 there was a cluster of cases reported from high elevation Kaski District of Gandaki Province. Our results suggest that dengue infections are increasing in magnitude and expanding out of the lowland areas to higher elevations over time.

CONCLUSIONS

There is a high risk of dengue outbreak in the lowland Terai region, with increasing spread towards the mid-mountains and beyond as seen over the last 14 years. Urgent measures are required to increase the availability of diagnostics and resources to mitigate future dengue epidemics.

Plasmid-Mediated AmpC β-Lactamase CITM and DHAM Genes Among Gram-Negative Clinical Isolates

Background

Antibiotic resistance mediated by the production of extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamases is posing a serious threat in the management of the infections caused by Gram-negative pathogens. The aim of this study was to determine the prevalence of two AmpC β-lactamases genes, bla_CITM and bla_DHAM, in Gram-negative bacterial isolates.

Materials and Methods

A total of 1151 clinical samples were obtained and processed at the microbiology laboratory of Annapurna Neurological Institute and Allied Science, Kathmandu between June 2017 and January 2018. Gram-negative isolates thus obtained were tested for antimicrobial susceptibility testing (AST) using Kirby–Bauer disk diffusion method. AmpC β-lactamase production was detected by disk approximation method using phenylboronic acid (PBA). Confirmed AmpC β-lactamase producers were further screened for bla_CITM and bla_DHAM genes by conventional polymerase chain reaction (PCR).

Results

Out of 1151 clinical specimens, 22% (253/1152) had bacterial growth. Of the total isolates, 89.3% (226/253) were Gram-negatives, with E. coli as the most predominant species (n=72) followed by Pseudomonas aeruginosa (n=41). In the AST, 46.9% (106/226) of the Gram-negative isolates were multidrug resistant (MDR). In disk diffusion test, 113 (50%) isolates showed resistance against cefoxitin, among which 91 isolates (83 by disk test and Boronic acid test, 8 by Boronic test only) were confirmed as AmpC β-lactamase-producers. In PCR assay, 90.1% (82/91) and 87.9% (80/91) of the isolates tested positive for production of bla_CITM and bla_DHAM genes, respectively.

Conclusions

High prevalence of AmpC β-lactamase-producers in our study is an alarming sign. This study recommends the use of modern diagnostic facilities in the clinical settings for early detection and management which can optimize the treatment therapies, curb the growth and spread of the drug-resistant pathogens.

Antibacterial and Antifungal Property of Actinomycetes Isolates from Soil and Water of Nepal

BACKGROUND

Human pathogens are rapidly acquiring resistance to antibiotics leading to treatment failure. We carried out this study to isolate and screen actinomycetes strains that have potential to kill bacterial and fungal pathogens.

METHODS

In this descriptive study 288 soil and water samples were processed by standard microbiological techniques at Central Department of Microbiology,Tribhuvan University from 2013 to 2015. Screened actinomycetes were cultivated for bioactive metabolite production and minimum inhibitory concentration (MIC) of metabolites were determined against bacterial pathogens including multidrug resistant bacteria and fungi.

RESULTS

One hundred twenty isolates having antimicrobial property were screened. Out of them, four most potent strains, Nocardiopsis prasina, Streptomyces violarus, Streptomyces krainskii and Streptomyces tsusimaensis were identified all having both antibacterial and anti-fungal property.Highest zone of inhibition (ZOI)was given by N. prasina against Candida albicans(41.33 ±1.15mm) and among bacteria, maximum ZOI was against Acinetobacter baumannii(31.33±3.05mm). MIC value of metabolite of N.prasina was 0.125mg/ml for E.coli and C. albicans. It was 2.5 mg/ml each for methicillin resistant Staphylococcus aureus (MRSA), A. baumannii and Salmonella Typhi and 0.625 mg/ml for Bacillus Subtilis.

CONCLUSIONS

Bioactive metabolite producing actinomycetes were recovered from soil and tested against human pathogenic bacteria and fungiand found to have antibacterial and antifungal property.

Extended spectrum beta-lactamase and metallo beta-lactamase production among Escherichia coli and Klebsiella pneumoniae isolated from different clinical samples in a tertiary care hospital in Kathmandu, Nepal

Background

Extended spectrum beta-lactamase (ESBL) and metallo beta-lactamase (MBL) production in Klebsiella pneumoniae and Escherichia coli are the commonest modes of drug resistance among these commonly isolated bacteria from clinical specimens. So the main purpose of our study was to determine the burden of ESBL and MBL production in E. coli and K. pneumoniae isolated from clinical samples. Further, the antimicrobial susceptibility patterns of E. coli and K. pneumoniae were also determined.

Methods

A cross-sectional study was conducted at Om Hospital and Research Centre, Kathmandu, Nepal by using the E. coli and K. pneumoniae isolated from different clinical samples (urine, pus, body fluids, sputum, blood) from May 2015 to December 2015. Antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion technique. Extended spectrum beta-lactamase production was detected by combined disc method using ceftazidime and ceftazidime/clavulanic acid discs and cefotaxime and cefotaxime/clavulanic acid discs. Similarly, metallo beta-lactamase production was detected by combined disc assay using imipenem and imipenem/ethylenediaminetetracetate discs. Bacteria showing resistance to at least three different classes of antibiotics were considered multidrug resistant (MDR).

Results

Of total 1568 different clinical samples processed, 268 (17.1%) samples were culture positive. Among which, E. coli and K. pneumoniae were isolated from 138 (51.5%) and 39 (14.6%) samples respectively. Of the total isolates 61 (34.5%) were ESBL producers and 7 (4%) isolates were found to be MBL producers. High rates of ESBL production (35.9%) was noted among the clinical isolates from outpatients, however no MBL producing strains were isolated from outpatients. Among 138 E. coli and 39 K. pneumoniae, 73 (52.9%) E. coli and 23 (59%) K. pneumoniae were multidrug resistant. The lowest rates of resistance was seen toward imipenem followed by piperacillin/tazobactam, amikacin and cefoperazone/sulbactam.

Conclusions

High rate of ESBL production was found in the E. coli and K. pneumoniae isolated from outpatients suggesting the dissemination of ESBL producing isolates in community. This is very serious issue and can’t be neglected. Regular monitoring of rates of ESBL and MBL production along with multidrug resistance among clinical isolates is very necessary.

Antibiotic resistance and biofilm production among the strains of Staphylococcus aureus isolated from pus/wound swab samples in a tertiary care hospital in Nepal

Background

The increasing drug resistance along with inducible clindamycin resistance, methicillin resistance and biofilm production among the strains of Staphylococcus aureus are present as the serious problems to the successful treatment of the infections caused by S. aureus. So, the main objectives of this study were to determine the antimicrobial susceptibility patterns along with the rates of inducible clindamycin resistance, methicillin resistance and biofilm production among the strains of S. aureus isolated from pus/wound swab samples.

Methods

A total of 830 non-repeated pus/wound swab samples were processed using standard microbiological techniques. The colonies grown were identified on the basis of colony morphology, Gram’s stain and biochemical tests. Antimicrobial susceptibility testing was performed by Kirby–Bauer disc diffusion technique. Detection of inducible clindamycin resistance was performed by D test, while detection of methicillin resistant S. aureus (MRSA) was performed by determination of minimum inhibitory concentration of oxacillin by agar dilution method. Similarly, detection of biofilm formation was performed by microtiter plate method. Strains showing resistance to three or more than three different classes of antibiotics were considered multidrug resistant.

Results

Total 76 samples showed the growth of S. aureus, among which 36 (47.4%) contained MRSA and 17 (22.4%) samples were found to have S. aureus showing inducible clindamycin resistance. Among the S. aureus isolated from outpatients, 41.9% were MRSA. Highest rates of susceptibility of S. aureus were seen toward linezolid (100%) and vancomycin (100%). Similarly, S. aureus isolated from 35 (46.1%) samples were found to be biofilm producers. Higher rate of inducible clindamycin resistance was seen among MRSA in comparison to methicillin susceptible S. aureus (MSSA). Similarly, higher rates of multidrug resistance and methicillin resistance were found among biofilm producing strains in comparison to biofilm non producing strains.

Conclusions

The rate of isolation of MRSA from community acquired infections was found to be high in Nepal. Increased rate of inducible clindamycin resistance as compared to previous studies in Nepal was noted. So for the proper management of the infections caused by S. aureus, D test for the detection of inducible clindamycin resistance should be included in the routine laboratory diagnosis. Further, detection of biofilm production should also be included in the routine tests. Linezolid and vancomycin can be used for the preliminary treatment of the serious infections caused by S. aureus.

Drug susceptibility patterns of the Mycobacterium tuberculosis isolated from previously treated and new cases of pulmonary tuberculosis at German-Nepal tuberculosis project laboratory, Kathmandu, Nepal

BACKGROUND

Multidrug resistant tuberculosis (MDR-TB) is a serious public health problem in Nepal. It is a major obstacle for the control of the tuberculosis. The main objectives of this study were to determine the prevalence of the multidrug resistant pulmonary tuberculosis and to evaluate the drug susceptibility patterns of Mycobacterium tuberculosis isolated from previously treated and newly diagnosed cases of pulmonary tuberculosis.

METHODS

A cross-sectional study was conducted from March 2013 to August 2013 at German-Nepal tuberculosis project (GENETUP) laboratory, Kathmandu, Nepal. For this the sputum samples from total of 153 (49 new and 104 previously treated) suspected pulmonary tuberculosis patients were used. The diagnosis of the tuberculosis was performed by using fluorescent microscopy and culture, while the drug susceptibility testing of Mycobacterium tuberculosis was performed by proportion method. Lowenstein-Jensen (L-J) medium was used for the culture of Mycobacterium tuberculosis and the colonies grown were identified on the basis of the colony morphology, pigment production and biochemical characteristics.

RESULTS

The prevalence of MDR-TB among all the cases of culture positive pulmonary tuberculosis was 15.6 %. The rate of MDR-TB among previously treated culture positive tuberculosis patients was 19.4 % and that among newly diagnosed culture positive pulmonary tuberculosis cases was 7.1 %. The highest rate of resistance of Mycobacterium tuberculosis, was toward streptomycin (24.4 %) followed by isoniazid (23 %), rifampicin (17.8 %) and ethambutol (15.6 %). Among the total of MDR-TB cases among previously treated patients, highest percentage of the cases were relapse (61.1 %) followed by chronic (16.7 %).

CONCLUSIONS

The high prevalence of DR/MDR-TB in our study reflects poor implementation of tuberculosis control program. On the basis of the drug susceptibility patterns of M. tuberculosis we found in our study, we recommend to include ethambutol instead of streptomycin in the multidrug therapy for the treatment of tuberculosis patients in Nepal. Further, due to high rate of MDR-TB among previously treated patients, we do not recommend to use first line drugs for the treatment of pulmonary tuberculosis among previously treated patients.

Minimum inhibitory concentration of vancomycin to methicillin resistant Staphylococcus aureus isolated from different clinical samples at a tertiary care hospital in Nepal

BACKGROUND

Methicillin resistant Staphylococcus aureus (MRSA) has evolved as a serious threat to public health. It has capability to cause infections not only in health care settings but also in community. Due to the multidrug resistance shown by MRSA, there are limited treatment options for the infections caused by this superbug. Vancomycin is used as the drug of choice for the treatment of infections caused by MRSA. Different studies from all around the world have documented the emergence of strains of S. aureus those are intermediate sensitive or resistant to vancomycin. And recently, there have been reports of reduced susceptibility of MRSA to vancomycin, from Nepal also. So the main purpose of this study was to determine the minimum inhibitory concentration (MIC) of vancomycin to methicillin resistant S. aureus isolated from different clinical specimens.

METHODS

Total 125 strains of S. aureus isolated from different clinical samples at KIST Medical College and Teaching Hospital, Lalitpur, Nepal from Nov 2012 to June 2013, were subjected to MRSA detection by cefoxitin disc diffusion method. The minimum inhibitory concentrations of vancomycin to confirmed MRSA strains were determined by agar dilution method. Yellow colored colonies in mannitol salt agar, which were gram positive cocci, catalase positive and coagulase positive were confirmed to be S. aureus.

RESULTS

Among, total 125 S. aureus strains isolated; 47(37.6%) were MRSA. Minimum inhibitory concentrations of vancomycin to the strains of MRSA ranged from 0.125 μg/ml to 1 μg/ml.

CONCLUSION

From our findings we concluded that the rate of isolation of MRSA among all the strains of S. aureus isolated from clinical samples was very high. However, none of the MRSA strains were found to be vancomycin intermediate-sensitive or vancomycin-resistant.

Re-emergence of the susceptibility of the Salmonella spp. isolated from blood samples to conventional first line antibiotics

Background

Enteric fever is an important public health problem in Nepal. Due to emergence of multidrug resistant strains of Salmonella spp. the conventional first-line drugs, ampicillin, chloramphenicol, and cotrimoxazole have not been used as empiric therapy for treatment of enteric fever for last two decades and there have been increased uses of fluoroquinolones as the drugs of choice. The aim of this study was to evaluate and analyze the antimicrobial susceptibility patterns of Salmonella spp.

Methods

A total of 620 blood samples collected from the patients suspected of suffering from enteric fever were cultured using standard microbiological techniques. Antibiotic susceptibility testing of the Salmonella spp., was performed by Kirby Bauer disc diffusion technique following Clinical and Laboratory Standard Institute (CLSI) guidelines. Minimum inhibitory concentrations of ciprofloxacin, ofloxacin and nalidixic acid were determined by agar dilution method.

Results

Of the total 83 Salmonella spp., 48 (57.83 %) were S. Typhi and 35 (42.26 %) were S. Paratyphi A. Among 83 Salmonella isolates, 98.8 % of the Salmonella spp. were susceptible to chloramphenicol and co-trimoxazole and about 97.6 % of the isolates were susceptible to ampicillin. Similarly, 69 (83.13 %) isolates were resistant to nalidixic acid. Only 16.9 % of the isolates were susceptible to ciprofloxacin. One S. Typhi isolate was multidrug resistant.

Conclusion

The present study revealed the decreased susceptibility of the S. Typhi and S. Paratyphi A to fluoroquinolones, proving them to be inappropriate for empirical therapy for the treatment of enteric fever in our setting. Further the higher susceptibility of the isolates to first line drugs, ampicillin, chloramphenicol, and cotrimoxazole suggests the possibility of using these drugs for empirical therapy.

Antibiotic Susceptibility Pattern of Bacterial Isolates Causing Wound Infection Among the Patients Visiting B & B Hospital

A wound is any physical injury involving a break in the skin, and exposed subcutaneous tissues provide a favorable substratum for a wide variety of microorganisms to contaminate and colonize. In this study a total of 870 plus samples were collected from patients visiting B & B hospital suspecting wound infection and then analyzed. The causative agents were isolated, identified by culture and biochemical tests and their susceptibility pattern to antibiotics were determined by using CLSI guidelines. Out of total samples, 476(44.8%) showed bacterial growth. Among growth cases 22.9% were mixed growths. Among all bacterial isolates, 12 species were identified of them, 70.6% were Gram-negative and 29.4% were Gram-positive. Among Gram-positive isolates, Staphylococcus. Aureus (74.2%) was most common followed by CoNS (8.6%), Non hemolytic Streptococci (8.6%), Enterococcus spp. (4.3%) and â -haemolytic Streptococci (4.3%). Among Gram-negative bacteria, the most common isolate was Pseudomonas aeruginosa (31.5%) followed by E.coli (24.8%), Acinetobacter spp. (14.6%), Enterobacter spp. (14.0%) and Klebsiella spp. (13.4%). Proteus spp. and Citrobacter spp. were less common. With regard to AST pattern, S. aureus was most susceptible to chloramphenicol and highly resistance to penicillin. Among them, 7.7% were MRSA. For other Gram-positive isolates as well, effective drug was found to be chloramphenicol. For P. aeruginosa, the most effective drug was imipenem (94.3%) followed by amikacin (63.2%). Likewise, for other Gram-negative bacteria most effective drug was imipenem followed by amikacin. Among the total P. aeruginosa isolates, 58.5% were found to be MDR. For all these P. aeruginosa isolates MIC on gentamycin and ciprofloxacin illustrate the simultaneous presence of ciprofloxacin resistance and reduced gentamycin susceptibility. These results indicated that antibiotic resistance in Gram-positive and Gram-negative bacteria were increasing in alarming trend that leads to the failure of treatment.DOI: http://dx.doi.org/njst.v15i2.12121Nepal Journal of Science and Technology Vol. 15, No.2 (2014) 91-96

Evaluation of Antibacterial Activities of Medicinal Plants

Plant and plant products are used as medicine from the beginning of human civilization. This study compares the antibacterial activity of crude hexane, ethylacetate and methanol extracts of nine different medicinal plants used in traditional Nepalese medicine, tested against 10 species of bacteria: Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 20063), Klebsiella oxytoca, Proteus mirabilis (ATCC 49132), Proteus vulgaris, Pseudomonas aeruginosa (ATCC 27853), Salmonella typhi, Salmonella paratyphi and Shigella dysenteriae by agar well diffusion method. The selected parts of these medicinal plants namely Acorus calamus (Rhizome), Aegle marmelos (Fruit), Asparagus racemosus (Tuberous root), Mimosa pudica (Root), Terminalia bellirica (Fruit), Terminalia chebula (Fruit), Tinospora cordifolia (Stem), Woodfordia fruticosa (Flower) and Holarrhena antidysenterica (Seed) were taken for study.The result showed that out of nine tested plants, four plant extracts (44%) showed activity against at least five or more tested bacteria and five plant extracts (56%) were active against three or less than three bacteria. None of the tested plant extracts was active against all the tested bacteria. A. racemosus was the least effective against bacterial species. S. aureus was the most susceptible bacteria being sensitive to 18 extracts from 9 medicinal plants. P. vulgaris was the most resistant bacteria being resistant to all selective plants. The MBC value ranges from 3.12 mg/ml to >50 mg/ml. Lowest MBC was shown by ethylacetate extract of T. bellirica against E. coli and ethylacetate extract of W. fruticosa against S. dysenteriae. Largest ZOI (31 mm) was produced by ethylacetate extract of T. bellirica. Nepal Journal of Science and Technology Vol. 13, No. 2 (2012) 209-214 DOI: http://dx.doi.org/10.3126/njst.v13i2.7738

Clinical and microbiological observational study on AmpC β-lactamase-producing Enterobacteriaceae in a hospital of Nepal

Limited information is available regarding AmpC β-lactamase (ABL)-producing Enterobacteriaceae compared to extended-spectrum β-lactamase-producing enterobacteria. Since ABL-producing organisms are often resistant to multiple antimicrobial agents, therapeutic options against these pathogens are limited. Among 230 clinical Enterobacteriaceae isolates, 64 (27.8%) were found to produce ABL in our study. Escherichia coli (83.9%) was a predominant pathogen, followed by Citrobacter freundii (5.2%). A significant proportion of ABL-producing isolates (81.3%) were found to be multidrug resistant against commonly used antibiotics. Univariate analysis showed that prior history of taking antibiotics (odds ratio [OR], 5.278; confidence interval [CI], 2.838–9.817; p < 0.001) and being inpatients (OR, 4.587; CI, 2.132–9.9; p < 0.001) were associated with ABL positivity. Regular antimicrobial resistance surveillance for ABL-producing Enterobacteriaceae is warranted for proper antimicrobial treatment strategy and policy making due to ABL-positive infections.

High prevalence of multidrug resistance in bacterial uropathogens from Kathmandu, Nepal

BACKGROUND

Urinary Tract Infection (UTI) is one of the most common infectious diseases and people of all age-groups and geographical locations are affected. The impact of disease is even worst in low-resource developing countries due to unaware of the UTIs caused by multidrug-resistant (MDR) pathogens and the possibility of transfer of MDR traits between them. The present study aimed to determine the prevalence of MDR bacterial isolates from UTI patients, the antibiotic resistance pattern and the conjugational transfer of multidrug resistance phenotypes in Escherichia coli (E. coli).

RESULTS

Two hundred and nineteen bacterial isolates were recovered from 710 urine samples at Kathmandu Model hospital during the study period. All samples and isolates were investigated by standard laboratory procedures. Among the significant bacterial growth (30.8%, 219 isolates), 41.1% isolates were MDR. The most prevailing organism, E. coli (81.3%, 178 isolates) was 38.2% MDR, whereas second most common organism, Citrobacter spp. (5%, 11 isolates) was found 72.7% MDR. Extended-spectrum β-lactamase (ESBL) production was detected in 55.2% of a subset of MDR E. coli isolates. Among the 29 MDR E. coli isolates, plasmids of size ranging 2-51 kb were obtained with different 15 profiles. The most common plasmid of size 32 kb was detected in all of the plasmid-harbored E. coli strains. The majority of E. coli isolates investigated for the multidrug resistance transfer were able to transfer plasmid-mediated MDR phenotypes along with ESBL pattern with a frequency ranging from 0.3 × 10-7 to 1.5 × 10-7 to an E. coli HB101 recipient strain by conjugation. Most of the donor and recipient strain showed high levels of minimum inhibitory concentration (MIC) values for commonly-used antibiotics.

CONCLUSIONS

The high prevalence of multidrug resistance in bacterial uropathogens was observed. Particularly, resistance patterns were alarmingly higher for amoxycillin, co-trimoxazole, flouroquinolones and third-generation cephalosporins, which necessitate the re-evaluation of first and second line therapies for UTI. In addition, conjugational co-transfer of MDR phenotypes with ESBL-positive phenotypes was observed in MDR E. coli.

Study of parasitic infection among children of Sukumbasi Basti in Kathmandu valley

Keeping in view of heavy burden of intestinal parasitosis, present study was done to find out the prevalence of intestinal parasitic infection in children (aged <16 years) of Sukumbasi (people living without land ownership) Basti (community) in Kathmandu Valley. A total of 279 stool samples collected in clean, dry and screw capped plastic container were firstly examined for the presence of adult worm and/or segments of worms. Samples fixed in 10% formal-saline were then examined microscopically after concentration by formal-ether sedimentation technique. Overall parasite positive rate was 43.3% (121/279) with no significant difference in two genders (Boys: 48.3%, 73/151; Girls: 37.5%, 48/128) (p=0.07). Altogether 11 species of parasites were detected. Of them Giardia lamblia was most common followed by Entamoeba histolytica, Trichuris trichiura and others. Positive rate was higher in Tibeto-Burman (55.0%, 77/140) and the least in Indo-Aryan (25.4%, 27/ 106) (p=0.01) ethnic groups. Children taking anti-parasitic drug in last six months had significantly low positive rate (25.4%, 15/59) than others (48.2%, 106/220) (p=0.002). Results of this study suggestive of periodic administration of anti-parastic drugs and need for improvement of sanitary/hygienic practice.

Clinical profiling and use of loop-mediated isothermal amplification assay for rapid detection of Mycobacterium tuberculosis from sputum

BACKGROUND

Tuberculosis is a global health problem and the situation is worsening with newer incidences of drug resistance and HIV association. Diagnosis of tuberculosis can be done by many methods and test, culture of sputum being the ideal one. Nucleic acid amplification (NAA) assay are more time efficient one, that amplify and detect specific nucleic acid sequences allows rapid, sensitive and specific detection of M. tuberculosis in sputum samples.

OBJECTIVES

The present study intends to compile the clinical presentations of the pulmonary tuberculosis (PTB) patients and to evaluate the efficacy of in-house loop-mediated isothermal amplification (LAMP) in detecting Mycobacterium tuberculosis in sputum samples by comparing with microscopy and culture.

MATERIALS AND METHODS

Two hundred two sputum samples were collected from 202 patients at National Tuberculosis Center, Bhaktapur, Nepal. Complete clinical profiling, epidemiological data and record on BCG vaccination were noted and the samples were subjected for microscopy, culture and in-house LAMP with six primers specific for 16S RNA gene of Mycobacterium tuberculosis.

RESULT

Of the 176 cases of clinical profiling, productive cough was most common symptom in 147 (83.52%), followed by chest pain 136 (77.27%), fever 133 (75.56%) and haemoptysis 61 (34.66%). There was a statistically significant association between BCG vaccination and development of TB (chi(2)=5.33, P=0.02). Of 202 cases, 115 (56.93%) were chest X-ray positive, 101(50%) were direct smear-positive and 100 (49.51%) were culture positive. LAMP had a sensitivity of 97% and specificity of 94.12% while comparing with culture. In addition, its sensitivity and specificity were 91.09% and 89.11% respectively with reference to microscopy.

CONCLUSION

As in our previous study, overall, the result of present study further confirms that the in-house LAMP is a simple, rapid, sensitive and specific DNA amplification technique for PTB diagnosis. Because of rapidity of microscopy and specificity of culture, in-house LAMP assay can be used as a very powerful and useful supplementary tool with complete clinical profiling of the patients for rapid diagnosis of TB in both AFB-positive and negative cases who are suspected as PTB in disease endemic country like Nepal.

Development of an in-house loop-mediated isothermal amplification (LAMP) assay for detection of Mycobacterium tuberculosis and evaluation in sputum samples of Nepalese patients

A number of nucleic acid amplification assays (NAAs) have been employed to detect tubercle bacilli in clinical specimens for tuberculosis (TB) diagnosis. Among these, loop-mediated isothermal amplification (LAMP) is an NAA possessing superior isothermal reaction characteristics. In the present study, a set of six specific primers targeting the Mycobacterium tuberculosis 16S rRNA gene with high sensitivity was selected and a LAMP system (MTB-LAMP) was developed. Using this system, a total of 200 sputum samples from Nepalese patients were investigated. The sensitivity of MTB-LAMP in culture-positive samples was 100 % (96/96), and the specificity in culture-negative samples was 94.2 % (98/104, 95 % confidence interval 90.5-97.9 %). The positive and negative predictive values of MTB-LAMP were 94.1 and 100 %, respectively. These results indicate that this MTB-LAMP method may prove to be a powerful tool for the early diagnosis of TB.

Etiological agents of bacteraemia and antibiotic susceptibility pattern in Kathmandu Model Hospital

The presence of bacteria in blood is simply known as bacteraemia. The main aim of this study is to determine the bacteraemia in patients visiting Kathmandu Model Hospital and antibiotic susceptibility pattern of isolates with special interest on ciprofloxacin. This prospective study was carried out in microbiology laboratory, Kathmandu Model Hospital from April 2005 to June 2005. Standard procedure was followed for blood sample collection. The bacteria were isolated and identified by standard microbiological procedure. Further, antibiotic susceptibility test was determined by NCCLS recommended Kirby-Bauer disc diffusion method. Out of 532 culture requests, 123 samples showed evidential microbial growth. The number of isolate of Salmonella typhi, Salmonella paratyphi A and Escherichia coli were 78, 44 and one respectively. The antibiotic susceptibility test demonstrated that chloramphenicol was the foremost drug of choice among the tested antibiotics with its sensitive rate of 98.4%. All the isolates of Salmonella typhi were susceptible to ceftriaxone and all isolates of Salmonella paratyphi A were susceptible to chloramphenicol, cotrimoxazole and amoxycillin. Ciprofloxacin resistant serotype of Salmonella was not isolated but out of 16 isolated serovar of Typhi and 10 serovar of Paratyphi A screened with nalidixic acid, 10 serovar of Typhi and all serovar of Paratyphi A were found to be resistant. Three isolates of Salmonella typhi were found as multidrug resistant (MDR) whereas no MDR was found in Salmonella paratyphi A. From this it can be concluded that Salmonella bacteraemia is more than other. Although nalidixic acid resistant serovars were isolated, ciprofloxacin resistant serovar were not present.

Microbial study of hospital environment and carrier pattern study among staff in Nepal Medical College Teaching Hospital

The present study was done to see the microbial flora in the environment (air and surface) of Nepal Medical College Teaching Hospital and the staffs working in the hospital. Altogether 160 environmental (air n = 43, surface n = 117) samples were collected and studied from different wards. Similarly 150 samples (48 nasal swabs, 48 throat swabs and 54 hand samples) from the staffs were collected and studied following the standard microbiological protocols. Gram +ve cocci were the most predominant ones among the bacterial isolates from the environment followed by gram +ve bacilli and gram -ve bacilli. Among fungal isolates, yeast were the most common isolates while Aspergillus spp. were the most frequently occurring mold. Out of 150 samples collected for the study of carrier pattern, 32 out of 54 samples collected were found to have Staphylococcus aureus in their hands, 1 had Escherichia coli. Other isolates were Bacillus spp., Micrococci and coagulase negative staphylococci. Similarly 21 (43.8%) out of 48 nasal samples were found to have S. aureus while none of the staffs were found to have beta-hemolytic streptococci in their throat. In the study, 1.6% environmental isolates and 5.7% carrier isolates of S. aureus were found to be Methicillin resistant.

Total spinal anaesthesia in association with insertion of a paravertebral catheter

An association between intercostal nerve block and the development of a total spinal is rare. Usually, subarachnoid injection is considered to have followed intraneural placement or inadvertent entrance into a dural cuff extending beyond an intervertebral foramen. We report a patient that followed injection of local anaesthetic into a paravertebral catheter sited at surgery in the thoracic paravertebral space of a patient undergoing thoracotomy. This was a life-threatening event that occurred on two occasions before the definitive diagnosis was made. It is considered likely that the paravertebral catheter entered an intervertebral foramen and the tip perforated the dura.

Detection of Enteric Bacterial Pathogens (Vibrio Cholerae and Escherichia Coli O157) in Childhood Diarrhoeal Cases

A hospital based cross sectional study was carried out in stool samples collected from cases of diarrhoea in children admitted to Oral Rehydration Therapy (ORT) ward, Kanti Children Hospital, Maharajgung. A total of 204 stool samples collected from children below 15 years were processed at Department of Microbiology, Bir hospital during the study period, February 2004 to June 2004.The stool specimens were investigated for Vibrio cholerae, as well as E. coli O157. Bloody stools were more focused for isolation of E. coli O157. Out of 204 patients, 60.3% were male and 39.7% were female. The largest number of diarrhoeal patients belong to age group 0-5 years i.e. 112 (54.9%). Vibrio cholerae O1 was found in 86 (42.2%) cases. All V. cholerae O1 belong to Ogawa serovar and El Tor biotype. Out of 86 isolates, 52.3% were from male patient and 47.7% were from female patient. Highest incidence of V. cholerae O1 was found in age groups 5-10 (46.5%) Isolation of V. cholerae in 10 cases even in age group 0-2 was remarkable feature. Incidence of V. cholerae O1 was highest in the month of April (61.5%). E. coli O157 could not be detected in this study. Predominant or pure growth of sorbitol non fermenting (SNF) strains which were biochemically identified as E. coli but not agglutinated with E.coli antiserum were found in five cases. Tetracycline was 100 percent effective antibiotic followed by Norfloxacin and Ciprofloxacin to V. cholerae O1. In this study, patients suffering with cholera were mostly from Kalanki. People using municipal tap water were mostly affected (51.8%) Out of 30 isolates of processed, 22 isolates showed toxin production. Key words: Vibrio cholerae; E. coli O157; Sorbital non fermenting; Cholera toxin. DOI: 10.3126/sw.v5i5.2651 Scientific World, Vol. 5, No. 5, July 2007 23-26

Isolation and Characterization of Antibacterial Actinomycetes from Soil Samples of Kalapatthar, Mount Everest Region

Seventy-nine Actinomycetes were isolated from soils of Kalapatthar (5545m), Mount Everest region. Twenty seven (34.18%) of the isolates showed an antibacterial activity against at least one test-bacteria among two Gram positive and nine Gram negative bacteria in primary screening by perpendicular streak method. Thirteen (48.15%) showed antibacterial activity in secondary screening. The result showed that three of the isolates, K.6.3, K.14.2, and K.58.5 were highly active with an inhibition zone e"20mm and broad spectrum antibacterial activity including two methicillin resistant Staphylococcus aureus (MRSA) strains. Minimum inhibitory concentration (MIC) of antibacterial metabolites of the isolate K.6.3 was 1mg/ml, and that of isolates K.14.2 and K.58.5 was 2mg/ml. Two spots were detected on thin layer chromatography plate from each of the metabolites which was completely different from the spot produced by vancomycin. The active isolates from primary screening were heterogeneous in their overall macroscopic, biochemical, and physiological characteristics through unweighted pair group method using average (UPGMA) cluster analysis. Delineation of the three active isolates showing potent broad spectrum antibacterial activity revealed that they belonged to distinct taxonomic groups.Key words: Antibacterial activity; Minimum inhibitory concentration; Thin layer chromatographyDOI: 10.3126/njst.v10i0.2957Nepal Journal of Science and Technology Vol. 10, 2009 Page: 173-182 

Microbiological Analysis of Drinking Water of Kathmandu Valley

Drinking water quality assessment in Kathmandu valley has always been crucial with reference to public health importance. A study was conducted to evaluate the quality of drinking water of the valley. A total of 132 drinking water samples were randomly collected from 49 tube wells, 57 wells, 17 taps and 9 stone spouts in different places of Kathmandu valley. The samples were analyzed for microbiological parameters. Total plate and coliform count revealed that 82.6% and 92.4% of drinking water samples found to cross the WHO guideline value for drinking water. During the study, 238 isolates of enteric bacteria were identified, of which 26.4% were Escherichia coli, 25.6% were Enterobacter spp, 23% were Citrobacter spp, 6.3% were Pseudomonas aeruginosa, 5.4% were Klebsiella spp, 4.0% were Shigella spp, 3.0% were Salmonella typhi, 3.0% were Proteus vulgaris, 3.0% were Serratia spp and 1.0% were Vibrio cholerae . Key words: Drinking water; Public health; Coliform; Bacteria. DOI: 10.3126/sw.v5i5.2667 Scientific World, Vol. 5, No. 5, July 2007 112-114