Naba Kumar Hazarika

Prevalence of blaTEM , blaSHV and blaCTX-M genes in clinical isolates of Escherichia coli and Klebsiella pneumoniae from Northeast India

AIM This study was carried out to determine the presence of blaTEM , blaSHV and blaCTX-M genes in extended-spectrum β-lactamase (ESBL) producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) at a tertiary care referral hospital in Northeast India. MATERIALS AND METHODS A total of 270 E. coli and 219 K. pneumoniae isolates were recovered during the period between August 2009 and July 2010. Kirby-Bauer disk diffusion method was performed to determine the antibiotic resistance pattern. Screening and phenotypic confirmatory test for ESBL production were performed using standard disc diffusion methods. Each of the initial ESBL screening test isolate was investigated for the presence of blaTEM , blaSHV and blaCTX-M genes via polymerase chain reaction (PCR) using gene-specific primers. RESULTS Phenotypic confirmatory test able to detect ESBL production in 73.58% of E. coli and 67.24% of K. pneumoniae. However, PCR amplification showed the presence of one or more ESBL genes in each of the initial ESBL screening positive isolate. Among three ESBL genotypes, the most prevalent genotype was found to be blaCTX-M in E. coli (88.67%) and blaTEM in K. pneumoniae (77.58%) ESBL producing isolates. Majority of ESBL producing isolates possess more than one ESBL genes. CONCLUSION This study constituted a primer report on high prevalence of blaTEM and blaCTX-M genes in ESBL producing isolates of E. coli and K. pneumoniae and denotes the need of more extensive studies on these antibiotic genes to determine the magnitude of the problem of antibiotic resistance exiting in this locality.

Incidence of blaNDM-1 gene in Escherichia coli isolates at a tertiary care referral hospital in Northeast India

PURPOSE Increasing reports on New Delhi metallo-β-lactamase-1 (NDM-1) producing Escherichia coli constitute a serious threat to global health since it is found to be highly resistant to most of the currently available antibiotics including carbapenems. This study has been performed to find out the incidence blaNDM-1 in E. coli isolates recovered from the various clinical samples at a tertiary care referral hospital in Northeast India. MATERIALS AND METHODS A total of 270 non-duplicated E. coli isolates were recovered from the various clinical samples at a tertiary care referral hospital in Northeast India. All isolates with reduced susceptibility to meropenem or ertapenem (diameter of zones of inhibition, ≤ 21 mm) were further phenotypically confirmed for carbapenemase production by modified Hodge test. All screened isolates were also subjected to the polymerase chain reaction detection of blaNDM-1 gene and additional bla genes coding for transmission electron microscopy, SHV, CTX-M, and AmpC. RESULTS Out of 270 E. coli isolates, 14 were screened for carbapenemase production on the basis of their reduced susceptibility to meropenem or ertapenem. All screened isolates were found to be positive for blaNDM-1 . Each of the blaNDM-1 possessing isolate was also positive for two or more additional bla genes, such as blaTEM , blaCTX-M and blaAmpC . Phylogenetic analysis showed very less variation in blaNDM-1 gene with respect to blaNDM-1 possessing E. coli isolates from other parts of India and abroad. CONCLUSIONS Our findings highlight the incidence of blaNDM-1 in E. coli isolates with a reduced susceptibility to meropenem or ertapenem.

Microscopy for cryptosporidiosis screening in remote areas

increased the ability of HIV-1 RT to effectively discriminate between the normal substrate dCTP and 3TC-triphosphat and G333D also enhanced the ability of RT containing TAMs and M184V to bind template/primer terminated by AZTmonophosphate, thereby restoring ATP-mediated excision of AZT-MP under steady-state assay conditions.[4] In this theoretical research, the author tried to explain the energy change corresponding to the G333D mutation within HIVRT. Here, the author found that both mutants critically affect the net energy requirement. Decreased energy requirement can be observed. It should be mentioned that not only the quantum energy change but also the conformational change due to mutation can be expected. These two phenomena bring the difÞ culties for occurrence of reaction and further imply the drug resistance. The results from this study can be useful for antiretroviral drug design and coping with the problem of G333D mutation HIV-RT-related drug resistance. This study can be a good model for further study in this area. The author suggests further studies on other mutants of HIVRT and their effects on drug resistance.

New Delhi metallo-β-lactamase and extended spectrum β-lactamases co-producing isolates are high in community-acquired urinary infections in Assam as detected by a novel multiplex polymerase chain reaction assay.

Background: The ability of microorganisms to evade antibiotic pressure is challenging in healthcare as patients have little or no drug treatment options. Detection of the prevalence of antibacterial resistance pattern helps towards improved antibiotic policy and empirical treatment. Objectives: We carried out antibiogram profiling and documented the prevalence and co-prevalence of New Delhi metallo-β-lactamase (NDM) and extended spectrum β-lactamases (ESBL) encoding genes in urinary Escherichia coli and Klebsiella pneumonia isolates. Materials and Methods: Antibiotic susceptibilities were tested for 241 isolates of E. coli and K. pneumoniae from urine samples collected from out- and hospitalised patients. Polymerase chain reaction (PCR) was carried out on isolates tested positive for phenotypic production of metallo-β-lactamase and ESBL. A multiplex PCR assay was designed to detect the genes. Results: Multiplex PCR assay designed had a limit of detection of 10 3 CFU/mL in vitro. NDM detected was significantly higher among K. pneumoniae compared to E. coli (69.2% vs. 18.2%; P = 0.001). Of 17, 14 NDM positive isolates also harboured ESBL genes. The co-production of CTX-M + TEM + NDM (3/9; 33.3% and 5/8; 62.5%) was most common in K. pneumoniae and E. coli, respectively while CTX-M + TEM + SHV + NDM was found in one isolate. Of the 156 phenotypically ESBL producing isolates, CTX-M, TEM and SHV was detected by PCR in 85, 53 and 24 isolates, respectively. Conclusion: NDM and ESBL co-producing isolates were both community (64.7%) and hospital (35.29%) acquired among E. coli. Antibiotic resistance can be effectively evaluated by a cost and time effective molecular method, such as the multiplex PCR used in this study, which complement culture and sensitivity tests.

First report on the detection of OXA-48 β-lactamase gene in Escherichia coli and Pseudomonas aeruginosa co-infection isolated from a patient in a Tertiary Care Hospital in Assam.

of extended-spectrum beta-lactamase production by Enterobacteriaceae. J Clin Microbiol 2011;49:1048-57. 6. Espinar MJ, Rocha R, Ribeiro M, Gonçalves Rodrigues A, Pina-Vaz C. Extended-spectrum ß-lactamases of Escherichia coli and Klebsiella pneumoniae screened by the VITEK 2 system. J Med Microbiol 2011;60 (Pt 6):756-60. 7. ß‐Lactamase Classification and Amino Acid Sequences for TEM, SHV and OXA Extended-Spectrum and Inhibitor Resistant Enzymes. Available from: http://www.lahey.org/ studies/. [Last accessed on 2015 Apr 11]. 8. BushK. The ABCD’s of ß-lactamase nomenclature. J Infect Chemother 2013;19:549-59.

Study on isolates of acute meningitis in a tertiary care centre in Assam.

Background: Meningitis is an inflammatory affection of the membranes surrounding the brain and spinal cord, which occurs as either a primary disease or secondarily to disease in some other part of the body. The epidemiological trend of acute meningitis varies with time and geography. Objective: To isolate the various agents of acute meningitis in all age group patients and to know the antimicrobial susceptibility pattern of bacterial isolates. Materials and Mathods: In this prospective study, a total of 316 cerebrospinal fluid (CSF) specimens were collected from patients showing signs and symptoms of acute meningitis and processed by standard microbiological methods in a tertiary care hospital in Guwahati, Assam over a period of one year, from August 2009 to July 2010. Results: Out of 316 CSF samples, bacterial and fungal culture positivity rate was found to be 16.13%. The most common bacterial isolate was Staphylococcus aureus , 29.41%. Isolation rate of Cryptococcus neoformans was 8%. All the Gram positive isolates were 100% sensitive to linezolid and vancomycin, whereas Gram negative isolates were 92% sensitive to polymyxin B. Conclusion: This study gives an idea about the changing trend of acute meningitis along with the changing in vitro antimicrobial susceptibility pattern of the bacterial isolates, which can help the clinicians to formulate the initial empiric therapy for patients of acute meningitis.

Clinicomycological profile of pityriasis versicolor in Assam

Background: Geographical variation in the distribution of Malassezia species associated with pityriasis versicolor (PV) has led to the necessity of studying epidemiological, mycological, and clinical characteristics of PV. Aims: To study the epidemiological, mycological, and clinical characteristics of PV in a tertiary care hospital. Settings and Design: The study was carried out with a cross-sectional design. Materials and Methods: Two hundred and sixty-two consecutive PV patients were subjected to detailed history, clinical examination, and investigations. Skin scrapings were processed by direct microscopy and culture. Isolates were identified by phenotypic characteristics and polymerase chain reaction-restriction fragment length polymorphism. Association of Malassezia species with clinical and epidemiological characteristics was studied. Statistical analysis of the data was done using statistical software. Results: Maximum number of PV cases (33.9%) belonged to the age group of 21–30 years with a male preponderance. 61.4% of the patients had a sedentary lifestyle, 70.2% showed the gradual onset of the disease, 51.1% presented with pruritus and in 66.4% of the patients symptoms were continuous. Most commonly involved body site was neck (27.8%), 77.09% of the lesions were bilaterally asymmetrical, 87.4% were macular, and 89.3% were hypopigmented. Malassezia furfur (77.3%) was the predominant species. Sedentary lifestyle (61.4%) and increased sweating (48%) were the most commonly associated predisposing factors. Conclusion: PV is more common in males. Distribution of Malassezia species varies significantly from those reported in other parts of India. M. furfur was the most common species responsible for PV in our region. Hence, further studies are required to evaluate the exact cause of this variation.

Prevalence of Vibrio cholerae O1 serogroup in Assam, India: A hospital-based study

Background & objectives: Although cholera remains to be an important public health problem, studies on reliable population-based estimates of laboratory confirmed cholera in endemic areas are limited worldwide. The aim of this hospital-based study was to evaluate the prevalence of Vibrio cholerae serogroup in Assam, India, during 2003-2013. Methods: Stool samples/rectal swabs were collected from acute watery diarrhoea (AWD) cases during 2003-2013 and processed by standard microbiological procedures. Antibiotic sensitivity test was done following the Clinical and Laboratory Standards Institute guidelines. Year-wise epidemiological trend of cholera was analyzed. Results: Cholera contributed to 3.93 per cent of AWD cases. In Assam, cholera was found to be more prevalent in the rural areas (6.7%) followed by the tea gardens (5.06%), urban slum (1.9%) and urban areas (1.4%). Highest proportion of cholera (13.7%) was observed in 0-10 yr age group. Of them, 11.5 per cent belonged to 0-5 yr age group. V. cholerae O1 El Tor serotype Ogawa was the predominant isolate. Multiple drug-resistant isolates of V. cholerae O1 Ogawa were reported in the study. Interpretation & conclusions: Emergence of resistance amongst V. cholerae towards many antibiotics is a matter of concern. Hence, continuous surveillance for diarrhoeal disorders is necessary to control the future outbreaks of cholera in this region.

Screening of Enhydra fluctuans for Phytochemical Composition and Broad-Spectrum Antibacterial Activity against Clinical Bacterial Isolates

ABSTRACT Enhydra fluctuans extracts were evaluated against numerous drug-resistant clinical isolates of methicillin-resistant Staphylococcus aureus and extended-spectrum beta-lactamase (ESBL)-and metallobetalactamase-producing Escherichia coli and Klebsiella pneumoniae. Antibacterial testing was carried out using the well diffusion method, and minimum inhibitory concentration (MIC) was calculated using the resazurin-based dye method. The extracts were also screened for phytochemical composition. Toluene extracts of the plant showed considerable antibacterial activity against gram-negative bacteria. MIC values ranged from 25 mg.mL–1 to 100 mg.mL–1 for selected isolates. Slight evidence of synergism was observed in combination studies with selected antibiotics.