Bharat Mani Pokhrel

NDM-8 Metallo-β-Lactamase in a Multidrug-Resistant Escherichia coli Strain Isolated in Nepal

ABSTRACT A novel metallo-β-lactamase, NDM-8, was identified in a multidrug-resistant Escherichia coli isolate, IOMTU11 (NCGM37), obtained from the respiratory tract of a patient in Nepal. The amino acid sequence of NDM-8 has substitutions at positions 130 (Asp to Gly) and 154 (Met to Leu) compared with NDM-1. NDM-8 showed enzymatic activities against β-lactams similar to those of NDM-1.

Emerging threat of multidrug resistant bugs – Acinetobacter calcoaceticus baumannii complex and Methicillin resistant Staphylococcus aureus

BackgroundInfections caused by bacteria such as multidrug resistant (MDR) Acinetobacter spp. and methicillin-resistant Staphylococcus aureus (MRSA) constitute a worldwide pandemic. Without gathering information about these strains, we cannot reduce the morbidity and mortality due to infections caused by these notorious bugs.MethodsThis study was conducted to identify the status of MDR Acinetobacter spp. and MRSA in a tertiary care centre of Nepal. Sputum, endotracheal aspirate and bronchial washing specimens were collected and processed from patients suspected of lower respiratory tract infection following standard microbiological methods recommended by the American Society for Microbiology (ASM). Double disk synergy test method was employed for the detection of extended-spectrum beta-lactamase (ESBL) in Acinetobacter isolates. Methicillin resistance in S. aureus was confirmed by using cefoxitin and oxacillin disks.ResultsDifferent genomespecies of Acinetobacter were isolated; these consisted of Acinetobacter calcoaceticus baumannii complex and A. lwoffii. Around 95% of Acinetobacter isolates were MDR, while 12.9% were ESBL-producer. Of the total 33 isolates of S. aureus, 26 (78.8%) were MDR and 14 (42.4%) were methicillin resistant.ConclusionsA large number of MDR Acinetobacter spp. and MRSA has been noted in this study. The condition is worsened by the emergence of ESBL producing Acinetobacter spp. Hence, judicious use of antimicrobials is mandatory in clinical settings. Moreover, there should be vigilant surveillance of resistant clones in laboratories.

Dissemination of multidrug-resistant Klebsiella pneumoniae clinical isolates with various combinations of carbapenemases (NDM-1 and OXA-72) and 16S rRNA methylases (ArmA, RmtC and RmtF) in Nepal

2008 0812M7303 Typhimurium 193 blaCTX-M-55 M 50 Thailand CHL, CIP, FFN, GEN, SUL, STR, TET 0811R10895 Typhimurium RDNC blaCTX-M-1 M 1 Unknown SUL,TET 0809W37247 Stanley blaCMY-2-like F 37 No AMC, CHL, FFN, SUL, STR, TET 0809F35063 Stanley blaCMY-2-like F 6 Unknown AMC, CHL, FFN, GEN, SUL, STR, TET 0808S63221 Typhimurium NT blaCMY-2-like M 20 Thailand AMC, CHL, FFN, SUL, STR, TET 0807F21428 Stanley blaCMY-2-like F 22 Thailand AMC, CHL, FFN, GEN, SUL, STR, TET 0806H16365 Stanley blaCMY-2-like M 2 Unknown AMC, CHL, FFN, GEN, SUL, STR, TET 0806R9615 Typhimurium U292 blaCTX-M-3 M 12 No None 0805R9530 Typhimurium NT blaCTX-M-14 M 47 Greece AMC, CHL, GEN, SUL, STR, TMP 2009 0911W58164 Heidelberg blaCTX-M-14 M 40 Egypt GEN, SUL, STR 0910W56953 subsp. enterica (I) blaCMY-2-like M 55 Thailand AMC, CHL, CIP, FFN, GEN, NAL, SUL, STR, TET 0910F48822 Isangi blaCMY-2-like, blaOXA-10 M <1 South Africa AMC, CHL, CIP, FFN, GEN, NAL, SUL, STR, TET, TMP

NDM-12, a Novel New Delhi Metallo-β-Lactamase Variant from a Carbapenem-Resistant Escherichia coli Clinical Isolate in Nepal

ABSTRACT A novel New Delhi metallo-β-lactamase variant, NDM-12, was identified in a carbapenem-resistant Escherichia coli clinical isolate obtained from a urine sample from a patient in Nepal. NDM-12 differed from NDM-1 by two amino acid substitutions (M154L and G222D). The enzymatic activities of NDM-12 against β-lactams were similar to those of NDM-1, although NDM-12 showed lower kcat/Km ratios for all β-lactams tested except doripenem. The blaNDM-12 gene was located in a plasmid of 160 kb.

Characterization of rotavirus causing acute diarrhoea in children in Kathmandu, Nepal, showing the dominance of serotype G12.

Diarrhoeal diseases are a major problem in developing countries. Though precise data on childhood mortality associated with diarrhoeal diseases in Nepal are not available, it has been estimated that approximately 25 % of child deaths are associated with diarrhoeal disease, particularly acute diarrhoea. The purpose of this study was to assess the incidence of rotavirus causing acute diarrhoea in children less than 5 years of age. A total of 525 children with acute diarrhoea in a childrens hospital of Kathmandu, Nepal, were enrolled between April and September 2011. The incidence of acute diarrhoea due to rotavirus was 25.9 % (136/525) as determined by ELISA. The percentage of rotavirus-infected males was higher (64.5 %) than females (35.5 %). The frequency of rotavirus cases was higher in children less than 2 years of age, among which the majority of cases (80.2 %) were in children between 6 and 24 months old (P<0.01). Genotypic characterization by RT-PCR revealed that the serotype G12 represented 55.9 % of cases in this study associated with P-types of either P[6], P[4] or P[8]. Further to this, a total of eight G/P combinations were identified, G12P[6] being the most common strain type of rotavirus in Nepal, with a prevalence rate of 46.4 %. The aim of this study was to find out the major genotypes of rotavirus causing acute diarrhoea in children.

Molecular epidemiology of multidrug-resistant Acinetobacter baumannii isolates in a university hospital in Nepal reveals the emergence of a novel epidemic clonal lineage.

The emergence of multidrug-resistant (MDR) Acinetobacter baumannii has become a serious medical problem worldwide. To clarify the genetic and epidemiological properties of MDR A. baumannii strains isolated from a medical setting in Nepal, 246 Acinetobacter spp. isolates obtained from different patients were screened for MDR A. baumannii by antimicrobial disk susceptibility testing. Whole genomes of the MDR A. baumannii isolates were sequenced by MiSeq™ (Illumina), and the complete genome of one isolate (IOMTU433) was sequenced by PacBio RS II. Phylogenetic trees were constructed from single nucleotide polymorphism concatemers. Multilocus sequence types were deduced and drug resistance genes were identified. Of the 246 Acinetobacter spp. isolates, 122 (49.6%) were MDR A. baumannii, with the majority being resistant to aminoglycosides, carbapenems and fluoroquinolones but not to colistin and tigecycline. These isolates harboured the 16S rRNA methylase gene armA as well as bla(NDM-1), bla(OXA-23) or bla(OXA-58). MDR A. baumannii isolates belonging to clonal complex 1 (CC1) and CC2 as well as a novel clonal complex (CC149) have spread throughout a medical setting in Nepal. The MDR isolates harboured genes encoding carbapenemases (OXA and NDM-1) and a 16S rRNA methylase (ArmA).

Medical students' characteristics as predictors of career practice location: retrospective cohort study tracking graduates of Nepal's first medical college.

Objective To determine, in one low income country (Nepal), which characteristics of medical students are associated with graduate doctors staying to practise in the country or in its rural areas. Design Observational cohort study. Setting Medical college registry, with internet, phone, and personal follow-up of graduates. Participants 710 graduate doctors from the first 22 classes (1983-2004) of Nepal’s first medical college, the Institute of Medicine. Main outcome measures Career practice location (foreign or in Nepal; in or outside of the capital city Kathmandu) compared with certain pre-graduation characteristics of medical student. Results 710 (97.7%) of the 727 graduates were located: 193 (27.2%) were working in Nepal in districts outside the capital city Kathmandu, 261 (36.8%) were working in Kathmandu, and 256 (36.1%) were working in foreign countries. Of 256 working abroad, 188 (73%) were in the United States. Students from later graduating classes were more likely to be working in foreign countries. Those with pre-medical education as paramedics were twice as likely to be working in Nepal and 3.5 times as likely to be in rural Nepal, compared with students with a college science background. Students who were academically in the lower third of their medical school class were twice as likely to be working in rural Nepal as those from the upper third. In a regression analysis adjusting for all variables, paramedical background (odds ratio 4.4, 95% confidence interval 1.7 to 11.6) was independently associated with a doctor remaining in Nepal. Rural birthplace (odds ratio 3.8, 1.3 to 11.5) and older age at matriculation (1.1, 1.0 to 1.2) were each independently associated with a doctor working in rural Nepal. Conclusions A cluster of medical students’ characteristics, including paramedical background, rural birthplace, and lower academic rank, was associated with a doctor remaining in Nepal and with working outside the capital city of Kathmandu. Policy makers in medical education who are committed to producing doctors for underserved areas of their country could use this evidence to revise their entrance criteria for medical school.

β-Lactamase-Producing Multidrug-Resistant Bacterial Pathogens from Tracheal Aspirates of Intensive Care Unit Patients at National Institute of Neurological and Allied Sciences, Nepal

The widespread use of tracheal intubation and mechanical ventilation to support the critically ill patients increases the risk of development of tracheobronchitis and bronchopneumonia. This cross-sectional study was conducted with an aim to isolate and identify bacterial pathogens from tracheal aspirates producing extended-spectrum β-lactamase (ESBL), AmpC β-lactamase, and metallo-β-lactamase (MBL) from August 2011 to April 2012 at National Institute of Neurological and Allied Sciences (NINAS), Kathmandu, Nepal. ESBL was detected by combined disk assay using cefotaxime and cefotaxime with clavulanate, AmpC β-lactamase by inhibitor-based method using cefoxitin and phenylboronic acid, and MBL by Imipenem-EDTA combined disk method. 167 bacterial strains were isolated from 187 samples and majority of them were Acinetobacter spp. followed by Klebsiella pneumoniae with 32.9% and 25.1%, respectively. 68.8% of isolates were multidrug resistant (MDR) and Acinetobacter spp. constituted 85.4%. ESBL, AmpC β-lactamase, and MBL were detected in 35 (25%), 51 (37.2%), and 11 (36.7%) isolates, respectively. Pseudomonas spp. (42.8%) were the predominant ESBL producer while Acinetobacter spp. were the major AmpC β-lactamase producer (43.1%) and MBL producer (54.5%).

Identification of a Novel NDM Variant, NDM-13, from a Multidrug-Resistant Escherichia coli Clinical Isolate in Nepal

ABSTRACT A novel New Delhi metallo-β-lactamase, NDM-13, was identified in a carbapenem-resistant Escherichia coli clinical isolate obtained from the urine of a patient in Nepal. The enzymatic activity of NDM-13 against β-lactams was similar to that of NDM-1. However, NDM-13 displayed significantly higher kcat/Km ratios for cefotaxime. The genetic environment of blaNDM-13 was determined to be tnpA-IS30-blaNDM-13-bleMBL-trpF-dsbC-cutA-groES-groL, with blaNDM-13 located within the chromosome.

High Prevalence of Panton-Valentine Leukocidin (PVL) Genes in Nosocomial-Acquired Staphylococcus aureus Isolated from Tertiary Care Hospitals in Nepal

Methicillin-resistant Staphylococcus aureus (MRSA) carrying the important virulence determinant, Panton-Valentine leukocidin (PVL), is an emerging infectious pathogen associated with skin and soft tissue infections as well as life-threatening invasive diseases. In carrying out the first PVL prevalence study in Nepal, we screened 73 nosocomial isolates of S. aureus from 2 tertiary care Nepali hospitals and obtained an overall PVL-positivity rate of 35.6% among the hospital isolates: 26.1% of MRSA and 51.9% of methicillin sensitive S. aureus (MSSA) isolates were found to be positive for the PVL genes. PVL prevalence was not associated with a specific (i) infection site, (ii) age group, or (iii) hospital of origin. It was found to be positively associated with heterogeneous MRSA (73.3%) compared to homogeneous MRSA (3.2%) and MSSA (51.9%); negatively associated with multiresistant MRSA (22%) compared to nonmultiresistant MRSA (60%) and MSSA (51.9%); and positively associated with macrolide-streptogramin B resistance (93.8%) compared to macrolide-lincosamide-streptogramin B resistance (0%) and no-resistance (45.8%) types. Macrolide-streptogramin B resistance was confirmed by the presence of msr(A) gene. Restriction pattern analyses provided evidence to support the circulation of a limited number of clones of PVL-positive MRSA, arguing for the adaptability of these isolates to a hospital setting.