INSIGHTS ON DRUG TARGETING OF TOXOPLASMA GONDII HOST INVASION PROTEINS: A REVIEW

Toxoplasma gondii is an obligate intracellular parasite that infects homoeothermic animals. It is also the major cause of retinochoroiditis in humans.Drugs targeting T. gondii proteins involved in the establishment of host-pathogen interactions is well documented to be an efficient way to combatthe infections. Basically, parasitic invasion of T. gondii occurs by the sequential secretion of apical membrane antigen 1 and rhoptry neck proteins onthe parasite and host cell surfaces, respectively. These proteins operate synergistically and form the moving junction (MJ) complex, thereby, enablingattachment and penetration of the parasite into the host cell. Better understanding of molecular interactions of these proteins is essential to develophighly efficient therapeutic modalities. Hence, by this review it is intended to update the current status of rhoptry and other MJ complex proteins asideal candidates for targeting T. gondii.Keywords: Toxoplasma gondii, Rhoptry proteins, Moving junction complex, Toxoplasmosis

Complication of Salmonella Bacteremia in a Case of Treated Fungal Endophthalmitis

This is to report a case of bacteremia caused by Salmonella typhi in a treated unilateral fungal endogenous endophthalmitis in an 18-year-old male from one of the South Asian countries. Microbiological and molecular investigations were carried out on the eviscerated material and routine blood culture was carried out. Direct examination of eviscerated material revealed the presence of fungal filaments. However, Salmonella typhi was isolated from both specimens, which was confirmed by Polymerase chain reaction targeting the 16SrRNA gene, sequencing, and random amplification of polymorphic DNA showed that they belonged to the same clone. The presence of Salmonella bacteremia in a treated unilateral fungal endophthalmitis, among young adult patients is rare and systemic symptoms should be investigated

The contribution of X-linked coding variation to severe developmental disorders

Abstract: Over 130 X-linked genes have been robustly associated with developmental disorders, and X-linked causes have been hypothesised to underlie the higher developmental disorder rates in males. Here, we evaluate the burden of X-linked coding variation in 11,044 developmental disorder patients, and find a similar rate of X-linked causes in males and females (6.0% and 6.9%, respectively), indicating that such variants do not account for the 1.4-fold male bias. We develop an improved strategy to detect X-linked developmental disorders and identify 23 significant genes, all of which were previously known, consistent with our inference that the vast majority of the X-linked burden is in known developmental disorder-associated genes. Importantly, we estimate that, in male probands, only 13% of inherited rare missense variants in known developmental disorder-associated genes are likely to be pathogenic. Our results demonstrate that statistical analysis of large datasets can refine our understanding of modes of inheritance for individual X-linked disorders

Diagnosis of Aspergillus fumigatus endophthalmitis from formalin fixed paraffin-embedded tissue by polymerase chain reaction-based restriction fragment length polymorphism

New molecular biological technique of Polymerase Chain Reaction (PCR) based Restriction Fragment Length Polymorphism (RFLP) can identify the species from paraffin-embedded tissue section. We demonstrated Aspergillus fumigatus fungus by PCR-based RFLP technique from paraffin section of an eyeball of an eight- month-old child removed for endogenous endophthalmitis

Clinico-microbiological Profile of Nontuberculous Mycobacterial Keratitis

Purpose: To assess the clinical and microbiological characteristics of nontuberculous mycobacterial (NTM) keratitis and to evaluate their response to medical therapy. Methods: Sixteen patients of NTM keratitis were retrospectively reviewed from May 2014 to May 2019. Laboratory diagnosis were made using Ziehl-Nielsen acidfast staining, routine culture method of isolation of nontuberculous mycobacteria and further identification of species by PCR (polymerase chain reaction)-based DNA sequencing targeting the heat shock protein-65 (hsp-65) gene. Results: Sixteen patients of microbiologically proven NTM keratitis were included. The average age at the time of presentation was 43.56 years (range, 24–73 years). The mean duration of symptoms was 2.23 months. The commonest risk factor was injury with organic material (43.7) followed by ocular surgery (25%). The majority of the nontuberculous mycobacteria were Mycobacterium abscessus (87.6%) followed by M. fortuitum (6.2%) and M. chelonae (6.2%). The in vitro sensitivity showed maximum sensitivity to Amikacin (AMK; 100%) followed by Azithromycin (AZM; 85.7%), and Clarithromycin (CLR; 85.7%). Out of a total of 16 patients, 12 (75%) had total success with medical therapy while 4 (25%) required surgical intervention. Conclusion: This study is focused on rapid and reliable identification of NTM keratitis through PCR-based identification method to enable effective medical management. The antibiotic susceptibility testing of different subspecies of NTM further reduced the need for surgical intervention. The effective role of AMK either alone or in combination with macrolide antibiotics is also highlighted in this study.&nbsp

Application of six multiplex PCR's among 200 clinical isolates of Pseudomonas aeruginosa for the detection of 20 drug resistance encoding genes

Pseudomonas aeruginosa (P. aeruginosa) is a menacing opportunistic, nosocomial pathogen; become a growing concern as conventional antimicrobial therapy is now futile against it. Multi-drug resistant P. aeruginosa (MDRPA) has distinctive resistance mechanisms such as production of β-lactamases, repression of porin genes and over-expression of efflux pumps. The focus of this study is to standardize and application of multiplex PCR (mPCR) to detect the presence of betalactamase genes encoding blaTem, blaOXA, blaCTX-M-15, blaVim, blaGes, blaVeb, blaDIM, AmpC and Efflux pump genes encoding Mex A,B-oprM, Mex C,D-oprJ, Mex X,Y-oprN, oprD, nfxB, MexR. A total of 200 clinical isolates of P. aeruginosa were tested for the presence of the above mentioned genes genotypically through mPCR and characterized by phenotypic methods for ESBL and MBL production. Out of 200 isolates, 163 (81.5%) nfxB regulator gene, 102 (51%) MexA, 96 (48%) MexC, 93 (46.5%) MexB, 86 (43%) MexD, 81 (40.5%) OprM, 74 (37%) OprJ, 72 (36%) OprD and MexR, 53 (26.5%) Mex X and OprN, 49 (24.5%) MexY gene. Betalactamase genes 145 (72.5%) blaTem, 67 (33.5%) blaOXA, 35 (17.5%) blaVim, 25(12.50%), 23 (11.50%) blaVeb, 21 (11.5%) blaGes, 14 (7%) Ctx-m and 10 (5%) AmpC and 5 (2.5%) blaDim-1 gene were tested positive by mPCR. Phenotypically 38 (19%) and 29 (14.5%) out of 200 tested positive for ESBL and MBL production. Application of this mPCR on clinical specimens is fast, accurate, specific and low-cost reliable tool for the screening, where culture negative Eubacterial PCR positive cases for an early molecular detection of drug resistance mechanism assisting the clinician to treat the disease with appropriate antibiotic selection

Antibiotic susceptibility pattern of rapidly growing mycobacteria

Background : The rapidly growing mycobacteria (RGM) causing human infections primarily consist of the Mycobacterium fortuitum group, Mycobacterium abscessus and Mycobacterium chelonae . The antibiotic susceptibility testing is important to determine the appropriate therapy as the antibiotics used to treat RGM are different from those used for treating infections caused by slow growers of mycobacteria. Aim : To determine antibiotic susceptibility of RGM using Kirby Bauer method and following Clinical and Laboratory Standards Institute (CLSI) guidelines. Settings and Design : Larsen and Toubro Microbiology Research Centre, Vision Research Foundation, Sankara Nethralaya, Chennai, Retrospective study. Materials and Methods : The antibiotic susceptibility testing was performed following CLSI method for the drugs Amikacin, Azithromycin, Tobramycin, Ceftazidime, Cephotaxime, Cefuroxime, Cefaperazone, Ceftriaxone, Ciprofloxacin, Ofloxacin, Norfloxacin, Gatifloxacin and Moxifloxacin. Results and Conclusions : Out of the 148 RGM isolates 146 (98%) were susceptible to amikacin, 138 (91%) to gatifloxacin, 132 (87%) to moxifloxacin, 122 (76%) to ciprofloxacin and 116 (74%) to Norfloxacin. Majority of the RGM were resistant to Ceftazidime, Cephotaxime and Cefaperazone. All the M. abscessus isolates were resistant to tobramycin. The in vitro antibiotic susceptibility testing by disc diffusion method showed that majority of the RGM were sensitive to Amikacin followed by Gatifloxacin, Moxifloxacin and Ciprofloxaci

Postoperative endophthalmitis due to Pseudomonas luteola: First reported case of acute and virulent presentation from a tertiary eye care center in South India

A 60-year-old male presented with pain and decreased vision 3 weeks following uneventful intracapsular cataract extraction with anterior vitrectomy for subluxated cataract. A diagnosis of acute endophthalmitis was made based on clinical and ultrasound features. Patient improved only after undergoing pars plana vitrectomies twice and repeated intravitreal antibiotic-steroid injections. Vitreous aspirate revealed Gram-negative bacillus identified as Pseudomonas luteola on culture. Patient returned with a retinal detachment at first follow-up which was treated with vitrectomy, endolaser, and silicone oil tamponade. To the best of our knowledge, this is the first case of P. luteola causing acute onset, virulent endophthalmitis reported in literature