Safety of photodynamic therapy involving optic nerve head

We present a case of large peripapillary polypoidal choroidal vasculopathy treated with standard-fluence photodynamic therapy (PDT) as other treatment options were unsuccessful or not justified. Due to large lesion size, treatment spot included part of optic disc also. PDT resulted in regression of polyp and visual improvement (from 20/300 to 20/20) without any collateral damage to optic nerve as evidenced by visual-field test and visual-evoked potential with a follow-up till 2 years. This case highlights the role of PDT as a safe alternative for treatment of large peripapillary lesion, even though the treatment spot encompasses part of the optic nerve head.

Performance of an in-house real-time PCR assay for detecting Cytomegalovirus infection among transplant patients from a tertiary care centre

Background: Quantitative Cytomegalovirus (CMV) polymerase chain reactions are increasingly being used for monitoring CMV DNAemia in haematopoietic stem cell transplants and solid organ transplants. Objective: In this study, a commercial CMV viral load assay was compared with an in-house viral load assay. Materials and Methods: A total of 176 whole-blood samples were tested for CMV DNAemia using both assays. Results: Our evaluation showed a difference of 1 log10copies/ml between the two assay systems in determining CMV viral loads in the clinical samples. Conclusion: The in-house viral load assay had a better correlation with clinical findings compared to the commercial assay. Quality assessment of these assays was done by the United Kingdom National External Quality Assessment Scheme (UKNEQAS), an external proficiency testing programme, and by the National Institute for Biological Standard and Control (NIBSC) standard. For UKNEQAS and NIBSC standards, the bias between the assays was 0.73 log10and 0.85 log10, respectively. This difference is well within the acceptable range already reported in the literature.

SHV-28, an extended-spectrum beta-lactamase produced by a clinical isolate of Klebsiella pneumoniae in south India.

SHV-28, an extended spectrum beta-lactamase from a clinical isolate of Klebsiella pneumoniae , had an isoelectric point of 7.6 and a substrate profile showing preferential hydrolysis for cefotaxime over ceftazidime. It differed from SHV-1 by one amino acid substitution. The conserved S-T-F-K and K-T-G motifs were identified by SHV-28 protein sequencing.

Molecular characterization of nosocomial CTX-M type beta-lactamase producing Enterobacteriaceae from a tertiary care hospital in south India.

CTX-M group of extended spectrum beta lactamases (ESBLs) represents a rapidly emerging problem in many countries. The prevalence of nosocomial bla CTX-M-1 producing Enterobacteriaceae strains has not been reported earlier in Indian hospitals. This study describes molecular subtyping of nosocomial bla CTX-M producing strains of Enterobacteriaceae . Polymerase chain reaction with primers specific for bla CTX-M-1 coding genes was used to identify 95 Enterobacteriaceae strains producing bla CTX-M positive isolates. Of the 95 bla CTX-M producing isolates, 45 strains were positive for bla CTX-M-1 . bla CTX-M-1 was found to be most prevalent in Klebsiella strains.

Validation of multiplex PCR strategy for simultaneous detection and identification of methicillin resistant Staphylococcus aureus.

Multiplex polymerase chain reaction (PCR) strategy is described for rapid identification of clinically relevant methicillin resistant Staphylococcus aureus (MRSA) that targets mecA and coagulase genes. In this study, 150 staphylococcal clinical isolates were used that included 40 isolates of MRSA, 55 isolates of methicillin susceptible S. aureus (MSSA), 44 isolates of methicillin susceptible coagulase negative Staphylococcus spp. (MS-CoNS) and 11 isolates of methicillin resistant coagulase negative Staphylococcus spp. (MR-CoNS). Out of 55 S. aureus strains, three strains demonstrated mecA gene, which appeared to be oxacillin sensitive by disc diffusion. When (MS-CoNS) were evaluated, 10 isolates classified as oxacillin sensitive phenotypically, yielded positive results in PCR method. The results for mecA detection by PCR were more consistent with disk susceptibility tests in case of MRSA (100%) and MSSA (95%) isolates. In contrast to above results with MRSA and MSSA, mecA detection by PCR in MS-CoNS showed less correlation with disk susceptibility tests (77%). The results for coag detection by PCR were consistent with phenotypic tests in all isolates.

Existence of proviral porcine endogenous retrovirus in fresh and decellularised porcine tissues.

PURPOSE: Swine are expected to be utilized as xenograft donors for both whole organ and cellular transplantation. A major concern in using porcine organs for transplantation is the potential of transmission of porcine endogenous retrovirus (PERV). Tissue-engineered or decellularised heart valves have already been implanted in humans and have been marketed by certain companies after Food and Drug Administration (FDA) approval. The aim of this study was to examine the existence of porcine endogenous retrovirus (PERV) in fresh and decellularised porcine tissues. METHODS: Porcine tissues (both fresh and decellularised) were analysed using validated assays specific for PERV: polymerase chain reaction (PCR), reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: PERV specific GAG sequences were found in the porcine heart tissue samples using PCR for DNA and RT- PCR for RNA. All tissue samples (both fresh and treated tissues) like aortic valve, pulmonary valve and heart muscle showed the presence of PERV DNA. RT PCR for PERV was positive in all fresh tissues and was found to be negative in decellularised treated tissues. CONCLUSIONS: PCR is a rapid, specific test for the detection of PERV virus in xenografts. These findings have demonstrated that the presence of proviral DNA form of PERV in porcine tissues needs to be carefully considered when the infectious disease potential of xenotransplantation is being assessed.

Prosthetic valve endocarditis caused by Scedosporium apiospermum.

Scedosporium apiospermum, the asexual state of Pseudallescheria boydii, is increasingly recognized as an opportunistic pathogen. We report a case of prosthetic valve endocarditis caused by this organism that developed in a patient following cardiac surgery.

Hydatid cyst of the left ventricle of the heart.

Hydatid disease of the heart is rare. We report a case of hydatid cyst of left ventricle in a forty year old lady where the diagnosis was made intra-operatively. The transthoracic and transesophageal echocardiography showed a mixed echogenic mass arising from the left ventricle. The diagnosis of hydatid cyst was confirmed by the demonstration of scolex and hooklets in the cyst fluid. Hydatid cyst should be a differential diagnosis for a mixed echogenic mass on echocardiography.

Prevalence, species distribution and antifungal sensitivity of vaginal yeasts in infertile women.

A total of 326 high vaginal swabs from infertile women attending the Institute of Reproductive Medicine were cultured from June 1999 to May 2000. Candida species was isolated from 42(12.88%) patients. Candida albicans (40.47%) followed by Candida glabrata (38.09%) were the most common isolates. Other species included Candida tropicalis (14.28%) and Candida krusei (7.14%). All isolates were tested for sensitivity by disc diffusion method on Yeast Nitrogen Agar base towards four antifungals. Seven (16.7%) candida strains showed resistance to Fluconazole and 19(45.23%) of the strains showed resistance to Itraconazole, and 4(9.5%) strains showed resistance to Nystatin. There was no resistance to Amphotericin B. Of the 7 strains resistant to Fluconazole, 3 were Candida krusei, 3 were Candida glabrata and 1 was Candida tropicalis.

Rapid identification of fluconazole resistance using Chrom agar Candida.

All though extremely rare 10 years ago, antifungal drug resistance is becoming a major problem in certain populations, especially in those infected with HIV. This study was undertaken to study the resistance of Candida species isolated in our hospital to Fluconazole using Chrom agar Candida. The Candida strains which were routinely isolated from clinical specimens like blood, urine, sputum, pus, fluid and homograft isolates were included in the study. 142 Candida isolates were tested by using Chrom agar Candida incorporated with Fluconazole. 16 strains were found to be resistant to Fluconazole and 126 strains sensitive to Fluconazole. Nine were C. tropicalis, 3 C. krusei, 2 C. guillermondii, 1 Geotrichum candidum and one was an unidentified strain of Candida. The MIC of the 16 strains were done using RPMI 1640 medium by macro broth dilution method. MIC of 9 strains was 64 & > 64 ug/ml of 6 strains 32 ug/ml and 1 strain 16 ug/ml.

Sclerosing mediastinitis caused by Aspergillus terreus.

A case of Aspergillus terreus causing sclerosing mediastinitis which presented with symptoms of cardiorespiratory compromise and compressive myelopathy is described. The diagnosis was established by culturing and isolating the fungus in pure culture from the tissue and was also confirmed by demonstration of sepcific precipitating antibodies against Aspergillus terreus in patient's serum.

Vaginal carriage of group B Streptococcus in infertile women.

From May, 1999 to April, 2000, 256 high vaginal swabs were culture from asymptomatic infertile women attending the out-patient department of the Institute of Reproductive Medicine. 41 strains of Streptococcus agalactiae were isolated from 33 patients (12.89%). Five patients had repeated isolations even after adequate therapy.

Rapid identification of fluconazole resistance using Chromagar Candida.

Although extremely rare 10 years ago, antifungal drug resistance is becoming a major problem in certain populations, especially in those infected with HIV. This study was undertaken to study the resistance of Candida species isolated in our hospital to Fluconazole using Chrom agar Candida. The Candida strains which were routinely isolated from clinical specimens like blood, urine, sputum, pus, fluid and homograft isolates were included in the study. 142 Candida isolates were tested by using Chrom agar Candida incorporated with fluconazole. 16 strains were found to be resistant to Fluconazole and 126 strains sensitive to Fluconazole. Nine were C tropicalis, 3 C krusei, 2 C guillermondii, 1 Geotrichum candidum and one was an unidentified strain of Candida. The MIC of the 16 strains were done using RPMI 1640 medium by macro broth dilution method. MIC of 9 strains was 64 & > 64 micrograms/ml of 6 strains 32 micrograms/ml and 1 strain 16 micrograms/ml.

Nasal carriage of methicillin resistant Staphylococcus aureus in a cardiovascular tertiary care centre and its detection by Lipovitellin Salt Mannitol Agar.

Ecological niches of Staphylococcus aureus are the anterior nares. Carriage of Staphylococcus aureus in the nose appears to play a key role in the epidemiology and pathogenesis of infection. Numerous studier have shown that elimination of nasal carriage using Mupirocin also eliminated hand carriage and the spread of infections in hospitals. Lipovitellin-Salt-Mannitol Agar was used for screening, isolation and presumptive identification of Staphylococcus aureus from nasal carriers. From November; 97 to August'98, 724 nasal swabs were cultured and 18.23% of health care workers were found to be nasal carriers of Staphylococcus aureus. Of these 12.15% were carriers of MRSA. The carrier rate was highest in December' 97 (32.07%). All MRSA carriers were treated with local application of Mupirocin for three days. A study of the antibiogram of the clinical isolates during the corresponding period showed 100% susceptibility of MRSA to Vancomycin. Susceptibility of MRSA to Clindamycin, Netilmycin, Rifampicin & Ofloxacin was 86.6%, 69.5%, 66% & 64.7% respectively.

Cryopreservation of cardiac homografts.

A homograft valve bank for cryopreservation of cardiac homografts was established at the Institute of Cardiovascular Diseases in July 1995. From July 1995 to February 1999, 169 donor hearts were processed. All except four hearts were procured post mortem. Aortic valves (149) and pulmonary valves (139) were the common homografts dissected out for use. The valves were immersed in a cocktail of five broad spectrum antibiotics and antifungals for an average of 48 to 72 hours before cryopreservation. Fifty-three (35.57%) aortic and 42 (30.21%) pulmonary valves had to be discarded for various reasons like fungal contamination, failure to sterilise, HBsAg positivity etc.; 153 homografts have been released for use so far. Analysing the usual methods of procurement, sterilisation protocol, culture and cryopreservation used for cardiac homografts at this centre, this paper recommends observance of timeliness, use of appropriate media for preservation of heart parts, administration of specific drugs and safeguards necessary for cryopreservation procedure.