L and crobiology Research Center

Chennai, India

L and crobiology Research Center

Chennai, India
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Murugan N.,L and crobiology Research Center | Murugan N.,SASTRA University | Malathi J.,L and crobiology Research Center | Umashankar V.,Center for Bioinformatics | Madhavan H.N.,L and crobiology Research Center
International Journal of Pharmacy and Pharmaceutical Sciences | Year: 2015

Objective: Ocular infections caused by Multi-Drug resistant (MDR) Pseudomonas aeruginosa are rare but increasingly identified recently. In this context, we have applied Next Generation Sequencing (NGS) based whole genome analysis on three ocular isolates of MDR P. aeruginosa to explore the drug resistance determinants and genomic level variations. Methods: Three ocular isolates namely P. aeruginosa VRFP03, VRFPA04 from two different Keratitis patients (corneal button) and VRFPA05 isolated from the intraocular specimen (Vitreous humor) collected from an endophthalmitis patient was included in this study. Phenotypically VRFPA03, VRFPA04, VRFPA05 showed resistant to a wide group of antibiotics and hence they were taken up for Ion Torrent-PGM based whole genome study. Results: Here, we report the first complete genome sequence of MDR P. aeruginosa VRFPA04 isolated from the Indian keratitis patients clinical specimen (corneal button) submitted to L & T Microbiology Research Centre, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India. The circular chromosome of P aeruginosa VRFPA04 was published under the NCBI accession number CP008739.2. Two Draft genome sequences of MDR P. aeruginosa VRFPA03 and VRFPA05 were published under the NCBI accession number ATNK01000000.1 and AXZJ01000000.1 respectively. Conclusion: Preliminary genomic analysis on P. aeruginosa VRFPA03, VRFPA04 and VRFPA05 revealed the presence of Metallo Beta-lactamase (MBL) genes blaDim-1, blaVim-2 and blaGes-9 genes respectively. These MBL genes were concordance with a phenotypic pattern of carbapenem resistance among VRFPA03, VRFPA04 and VRFPA05 strains, respectively. We are proud to share that this is the first of its kind to report blaDIM-1 from an Indian. © 2015, International Journal of Pharmacy and Pharmaceutical Science. All rights reserved.


Jambulingam M.,L and crobiology Research Center | Parameswaran S.K.,Vision Research Foundation | Lysa S.,Vision Research Foundation | Selvaraj M.,L and crobiology Research Center | Madhavan H.N.,L and crobiology Research Center
Indian Journal of Ophthalmology | Year: 2010

Background: The objective of the study was the determination of the incidence of culture-proven postoperative endophthalmitis and probable sources of infection. Materials and Methods: It was a prospective study on the microbiology, incidence and probable sources of infection in patients with postoperative infectious endophthalmitis carried out in a tertiary care eye hospital. Consecutive patients diagnosed with postoperative infectious endophthalmitis during the years 2000-2007 were investigated for the causative infective agent and possible sources of infection. The surgical data and microbiological data including the investigations performed to trace the source were recorded in a specific formatted form and were gathered and compiled for analysis. Results: Data of analysis showed that 98 (0.042%) out of 2,31,259 patients who underwent intra-ocular surgery developed infectious endophthalmitis. Among these, 70 (0.053%) occurred after cataract, 10 (0.5%) after penetrating keratoplasty (PK) and 18 (0.018%) following other types of intra-ocular surgeries. The predominant infectious agents isolated were bacteria (89.7%), with equal proportions of Gram-positive and Gram-negative bacteria. Polymicrobial infection was noted in four and fungi in seven patients. Occurrence of postoperative endophthalmitis was sporadic and not related to any specific part of period in a year. Sources of infection were donor corneal rim in six post-PK patients and phaco probe in one who had postphacoemulsification endophthalmitis Conclusions: Overall incidence of postoperative endophthalmitis over an 8-year period was quite low. The sources of infection could be established in six post-PK endophthalmitis patients and in a postcataract surgery.


Vimalin J.,L and crobiology Research Center | Gupta N.,Medical Research Foundation | Jambulingam M.,L and crobiology Research Center | Padmanabhan P.,Medical Research Foundation | Madhavan H.N.,L and crobiology Research Center
Cornea | Year: 2012

Purpose: To determine the effect of riboflavin-UV-A treatment on the corneal limbal epithelial cells during a corneal collagen cross-linking (CXL) procedure. Methods: Thirty freshly enucleated human cadaveric eyeballs were subjected to a CXL procedure, mimicking the clinical protocol. During the UV-A exposure, one half of the limbus (sector A) was left unprotected, whereas the other half (sector B) was covered by a metal shield. Limbal biopsies from both sectors before and after the procedure were analyzed. Each strip of tissue was divided into 3 segments, for cell count of viable cells, for cultivation on human amniotic membrane (HAM), and for stem cell and differentiated corneal epithelial cell marker studies using reverse transcriptase-polymerase chain reaction. Results: Compared with the cell count before CXL, there was a statistically significant drop in the mean number of viable cells after CXL in sector A but not in sector B. Biopsies from both sectors before CXL and from sector B after CXL showed good growth on HAM. Biopsies from sector A after CXL showed no growth on HAM. The putative stem cell marker ABCG2 was absent in all samples and p63 was absent in 3 of 10 samples taken from sector A after CXL. All markers were present in all samples from sector B after CXL. Conclusions: Riboflavin-UV-A treatment can result in damage to limbal epithelial cells, particularly the stem cells. Covering the limbal region with a metal shield effectively prevents this damage. Copyright © 2012 by Lippincott Williams & Wilkins.


Janani M.K.,L and crobiology Research Center | Malathi J.,L and crobiology Research Center | Madhavan H.N.,L and crobiology Research Center
Indian Journal of Medical Research | Year: 2012

Background & objectives: Though several viruses are responsible for conjunctivitis, but human adenovirus (HAdV) is by far the most common cause. Epidemic conjunctivitis causes morbidity and early detection of aetiological agent is essential in preventing spread of disease as some of serotypes of adenoviruses cause a severe form of conjunctivitis. This study was undertaken to identify the causative agent of conjunctivitis outbreak in Chennai in 2010. Methods: Conjunctival samples collected from 17 patients with conjunctivitis were subjected to virological investigations. Culture and PCR for detection of adenovirus and enterovirus were carried out. PCR positive products were further subjected for DNA sequencing. The nucleotide sequences of the hexons of isolates were analyzed by comparison with all 51 human adenovirus strains. Phylogenetic tree was constructed using DAMBE software. Results: Among 17 patients, seven were positive for adenovirus by PCR on the direct specimen, none was positive for enterovirus. Eleven of 30 conjunctival swabs showed cytopathic effect in HEp-2 cell line and were confirmed as HAdV by PCR. The DNA sequence data of the 11 isolates had equal percentage of homology with HAdV 6 and 2 on blast analysis. On phylogenetic analysis with GeneBank data of 51 adenovirus strains, 11 isolates from patients during the outbreak of conjunctivitis formed a separate clade indicating a new variant strain. Interpretation & conclusions: Based on phylogenetic analysis it was concluded that the recent conjunctivitis outbreak that occurred in Chennai was caused by a variant adenovirus strain.


Rishi E.,Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology | Rishi P.,Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology | Sengupta S.,Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology | Jambulingam M.,L and crobiology Research Center | And 3 more authors.
Ophthalmology | Year: 2013

Objective: To study the clinicomicrobiologic characteristics and treatment outcomes in eyes with acute postoperative endophthalmitis (APE) owing to Bacillus cereus from a tertiary eye-care center. Design: Retrospective, interventional case series. Participants: Case records of all eyes with culture-proven APE attributable to B cereus from January 2000 to May 2011 were identified from a computerized database and evaluated. Methods: Clinical features at time of presentation, microbiological characteristics, and treatment measures were recorded. A thorough literature search using PubMed and the Cochrane Library databases was done to identify all cases of APE owing to Bacillus species reported to date and clinical characteristics of these eyes was compared with our series. Main Outcome Measures: Structural (globe salvage) and functional (visual rehabilitation) outcomes at last follow-up visit. Results: We found 6 sporadic cases that experienced APE during the study period. All eyes had a fulminant onset within the first 24 hours of cataract surgery with extremely high intraocular pressure (IOP) and corneal edema similar to toxic anterior segment syndrome (TASS). However, these eyes progressed rapidly to develop corneal infiltrates, scleral and uveal tissue necrosis with hyphema, brownish exudates in anterior chamber and necrotizing retinitis within hours despite immediate initiation of intravitreal pharmacotherapy and vitrectomy. All eyes demonstrated gram-positive bacilli from the aqueous and B cereus was isolated, which was sensitive to conventional antibiotics except penicillin. Two eyes required therapeutic keratoplasty, combined with a scleral patch graft in 1 eye, 1 eye was eviscerated after 48 hours of onset of symptoms, and 2 eyes experienced phthisical changes within 10 days of onset. Conclusions: We found that APE owing to B cereus has an onset within 12 to 24 hours of intraocular surgery and simulates TASS in the first few hours. The clinical course is marked by rapidly worsening necrotizing infection, leading to very poor outcomes despite early institution of appropriate therapy. One must closely observe every case of TASS that presents with intense pain and extremely high IOP and rule out APE owing to B cereus with microbiologic testing. Financial Disclosure(s): The authors have no proprietary or commercial interest in any of the materials discussed in this article. © 2013 American Academy of Ophthalmology.


Moses S.,L and crobiology Research Center | Jambulingam M.,L and crobiology Research Center | Madhavan H.,L and crobiology Research Center
Journal of Postgraduate Medicine | Year: 2014

Introduction: Toll like receptors (TLRs) have been proven to play an important role in mounting the innate immune response in an infected host. The expression of TLRs against herpes simplex virus (HSV) have not been studied in retinitis. Therefore, the current study was undertaken to determine the same using the retinal pigment epithelial (ARPE-19) cell line. Materials and Methods: APRE cells cultured in vitro were challenged with HSV 1 and 2 standard strains and 20 other clinical isolates. The cells were observed for cytopathic changes. The cell culture harvest was subjected to RNA extraction using a Total RNA mini kit. The RNA was subjected to reverse transcriptase polymerase chain reaction (PCR) for the amplification of TLRs 3, 4 and 9 and GAPDH housekeeping gene. The amplified products were subjected to electrophoresis on a 2% agarose gel and viewed under a transilluminator. Results: TLR 3 and 4 were expressed by ARPE treated with all the 22 isolates. TLR 9 expression was seen in 16 of the 22 isolates. Bacterial contamination was ruled out by subjecting the harvests to PCR amplification of 16sRNA gene amplification of the eubacterial genome. Conclusions: The expression of TLR 4 has been reported for the first time in HSV infection. TLR 4 along with TLR 3 and 9 is responsible for the antiviral response in HSV infections.


Mahendradas P.,Superspeciality Eye Hospital and Post Graduate Institute of Ophthalmology | Shetty R.,Superspeciality Eye Hospital and Post Graduate Institute of Ophthalmology | Malathi J.,Superspeciality Eye Hospital and Post Graduate Institute of Ophthalmology | Madhavan H.N.,L and crobiology Research Center
Indian Journal of Ophthalmology | Year: 2010

We are reporting a case of bilateral Fuchs' heterochromic iridocyclitis with chikungunya virus infection in the left eye. A 20-year-old female was presented with a past history of fever suggestive of chikungunya with bilateral Fuchs' heterochromic iridocyclitis and complicated cataract. She had a tripod dendritic pattern of keratic precipitates by confocal microscopy in the left eye with a stippled pattern of keratic precipitates in both eyes. The real-time polymerase chain reaction (RT-PCR) assay in the aqueous humor detected 98 copies/ml of chikungunya virus RNA. The patient underwent clear corneal phacoemulsification with in-the-bag intraocular lens implantation in the left eye with a good visual outcome. This is the first report where the presence of chikungunya virus RNA has been associated with a case of bilateral Fuchs' heterochromic iridocyclitis.


Gokhale V.V.,Medical Research Foundation | Therese K.L.,L and crobiology Research Center | Bagyalakshmi R.,L and crobiology Research Center | Biswas J.,Medical Research Foundation
Journal of Cataract and Refractive Surgery | Year: 2014

We report a case of chronic low-grade endophthalmitis after cataract surgery presenting with recurrent episodes of severe anterior chamber reactions and hypopyon uveitis caused by Escherichia fergusonii, which was isolated from vitreous aspirate by polymerase chain reaction-based DNA sequencing. Polymerase chain reaction has emerged as an essential, powerful, and rapid laboratory diagnostic technique and a useful adjunct to the conventional gold standard. © 2013 ASCRS and ESCRS.


Sowmiya M.,L and crobiology Research Center | Malathi J.,L and crobiology Research Center | Madhavan H.N.,L and crobiology Research Center
Investigative Ophthalmology and Visual Science | Year: 2012

Purpose. Since, to our knowledge, there are no reports on the prevalence of the blaNDM-1 gene among ocular isolates of Enterobacteriaceae, and only limited information on the prevalence of extended spectrum beta-lactamases (ESBLs) among ocular bacterial isolates are available, our study was undertaken. Methods. A prospective study was done on 74 Enterobacteriaceae isolates from patients presenting with clinical suspicion of bacterial ocular infections during a period from January 2010-December 2011. All isolates were subjected to detection of ESBLs by double disc synergy and screened for the presence of CTX-M -I, II, III, and IV groups, and OXA, TEM, SHV, blaNDM-1 genes by PCR. Results. Of 74 ocular Enterobacteriaceae isolates 57 (77%) were ESBL producers tested by the double disc diffusion test. PCR-based DNA sequencing of these 57 ocular isolates showed the presence of CTX-M-15 (14.0%), blaOXA-1 (5.2%), blaSHV-1 (8.7%), and blaTEM-1 (7.0%) types. The blaNDM-1 was absent among these ocular isolates. The most widely disseminated ESBL gene among ocular isolates was CTX-M-15. Phenotypic and genotypic results showed 100% correlation. Conclusions. To our knowledge, this is the first extensive study performed to genotype ESBL-producing ocular Enterobacteriaceae isolates. The isolation of ESBL-producing Enterobacteriaceae organisms predominantly from conjunctival specimens indicates community-acquired infections/colonization by these bacteria in the conjunctiva of the patients, and cases are not related to hospital-acquired infections because of the short stay of ophthalmic patients in the hospitals. A shift in the resistance rates of ceftazidime from 37.5% to 79.7% over the years proves the increase in drug resistance among ocular clinical isolates. © 2012 The Association for Research in Vision and Ophthalmology, Inc.


Mahalakshmi B.,L and crobiology Research Center | Therese K.L.,L and crobiology Research Center | Devipriya U.,L and crobiology Research Center | Pushpalatha V.,L and crobiology Research Center | And 2 more authors.
Indian Journal of Medical Research | Year: 2010

Background & objectives: We undertook this study to determine the infectious aetiology of congenital cataract based on the presence of IgM antibodies to TORCHES [(Toxoplasma gondii (T. gondii), Rubella virus (RV), Cytomegalovirus (CMV), Herpes simplex virus (HSV) and Syphilis (caused by Treponema pallidum)] in the serum samples of congenital cataract patients. Methods: Serum samples collected from 593 infants and children (10 days to 12 months old) with clinically diagnosed congenital cataract at Sankara Nethralaya, a referral eye hospital in Chennai, were tested for the presence of specific IgG and IgM antibodies to T. gondii, RV, CMV, HSV by ELISA and specific treponemal antibodies by T. pallidum haemagglutination test (TPHA). Results: IgM antibodies were detected against T. gondii in 1.7 per cent, RV in 8.4 per cent, CMV in 17.8 per cent and HSV in 5.1 per cent, and that of specific IgG in 8.9, 25.0, 66.1 and 2.6 per cent respectively. Presence of IgM antibodies to T. Gondii in the study group was significantly lower when compared to IgM antibodies to RV, CMV and HSV. All serum samples were negative for the presence of anti treponemal antibodies by TPHA. Overall, IgM antibodies to one or more of the four infectious agents were detected in 20.2 per cent of the study population, and among these co-infections to more than one infectious agents were detected in 12.5 per cent. Interpretation & conclusion: The results of the present retrospective analysis showed association of RV, CMV, HSV and T. gondii with congenital cataract based on the presence of specific IgM antibodies.

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