A hybrid cationic peptide composed of human ß-defensin-1 and humanized θ-defensin sequences exhibits salt-resistant antimicrobial activity.

We have designed a hybrid peptide by combining sequences of human ß-defensin-1 (HBD-1) and θ-defensin, in an attempt to generate a molecule that combines the diversity in structure and biological activity of two different peptides to yield a promising therapeutic candidate. HBD-1 was chosen as it is a natural defensin of humans that is constitutively expressed, but its antibacterial activity is considerably impaired by elevated ionic strength. θ-Defensins are expressed in human bone marrow as a pseudogene and are homologous to rhesus monkey circular minidefensins. Retrocyclins are synthetic human θ-defensins. The cyclic nature of the θ-defensin peptides makes them salt resistant, nonhemolytic, and virtually noncytotoxic in vitro. However, a nonhuman circular molecule developed for clinical use would be less viable than a linear molecule. In this study, we have fused the C-terminal region of HBD-1 to the nonapeptide sequence of a synthetic retrocyclin. Cyclization was achieved by joining the terminal ends of the hybrid peptide by a disulfide bridge. The hybrid peptide with or without the disulfide bridge exhibited enhanced antimicrobial activity against both Gram-negative and Gram-positive bacteria as well as against fungi, including clinical bacterial isolates from eye infections. The peptide retained activity in the presence of NaCl and serum and was nonhemolytic in vitro. Thus, the hybrid peptide generated holds potential as a new class of antibiotics.

Endophthalmitis in Boston keratoprosthesis: case series and review of literature.

To report the clinical and microbiological characteristics of infectious endophthalmitis after Boston type I keratoprosthesis (B-K-Pro) implantation. Retrospective analysis of 136 eyes that received a B-K-Pro type 1 between 1999 and 2012 was performed. Five eyes with a diagnosis of exogenous endophthalmitis after B-K-pro type 1 were identified and information about demographic data, indication for K-Pro, post-operative bandage contact lens use, post-operative prophylactic antibiotic use, timing and clinical presentation of endophthalmitis, gram stain and culture results of intraocular fluid and preoperative and post-operative visual acuity were collected. The incidence of endophthalmitis was 3.67% (5 of 136 eyes) and average time to develop endophthalmitis was 5.62 months (range 2 days to 8 months). Mean patient age was 31.4 years (5 to 65 years). The surgical indications included corneal injury due to chemical burns (n = 2), multiple failed grafts secondary to microbial keratitis (n = 2) and congenital glaucoma with congenital herpetic keratitis (n = 1). Post-Boston K-Pro, the visual acuity ranged from light perception (LP) to 20/50. K-pro was explanted in 4 patients. There was bacterial and fungal growth in two patients each and one vitreous did not grow anything. All the eyes were phthisical at last visit. Infectious endophthalmitis after K-Pro implantation in our study had a higher incidence, early onset and extremely poor visual outcome compared with post-cataract surgery endophthalmitis, as reported in literature. Not only bacterial but also fungal infections are an important etiology for infectious endophthalmitis in these cases.

Erratum to: Endophthalmitis in Boston keratoprosthesis: case series and review of literature.

To report the clinical and microbiological characteristics of infectious endophthalmitis after Boston type I keratoprosthesis (B-K-Pro) implantation. Retrospective analysis of 45 eyes that received a B-K-Pro type 1 between 2009 and 2012 was performed. Five eyes with a diagnosis of exogenous endophthalmitis after B-K-pro type 1 were identified and information about demographic data, indication for K-Pro, post-operative bandage contact lens use, post-operative prophylactic antibiotic use, timing and clinical presentation of endophthalmitis, gram stain and culture results of intraocular fluid and preoperative and post-operative visual acuity were collected. The incidence of endophthalmitis was 11.1 % (5 of 45 eyes) and average time to develop endophthalmitis was 5.62 months (range 2 days to 8 months). Mean patient age was 31.4 years (5 to 65 years). The surgical indications included corneal injury due to chemical burns (n = 2), multiple failed grafts secondary to microbial keratitis (n = 2) and congenital glaucoma with congenital herpetic keratitis (n = 1). Post-Boston K-Pro, the visual acuity ranged from light perception (LP) to 20/50. K-pro was explanted in 4 patients. There was bacterial and fungal growth in two patients each and one vitreous did not grow anything. All the eyes were phthisical at last visit. Infectious endophthalmitis after K-Pro implantation in our study had a higher incidence, early onset and extremely poor visual outcome compared with post-cataract surgery endophthalmitis, as reported in literature. Not only bacterial but also fungal infections are an important etiology for infectious endophthalmitis in these cases.

Pythium insidiosum keratitis: clinical profile and role of DNA sequencing and zoospore formation in diagnosis.

PURPOSE: To report the molecular and microbiological diagnosis and clinical profile of 13 patients with Pythium insidiosum keratitis. METHODS: Phase 1 of the study consisted of DNA sequencing of the ITS region of the rDNA of 162 stocked morphologically unidentified nonconsecutive fungal isolates from corneal scraping of patients with keratitis (2010-2012). Blast and phylogenetic analyses of the sequences showed 9 to be P. insidiosum. A retrospective review of archived photographs of colony and direct microscopy of corneal scrapings and clinical records of the cases were performed. Phase 2 began in 2014, in which a simple method of zoospore formation was used for fungal colonies resembling those of P. insidiosum followed by DNA sequencing. RESULTS: The prevalence of P. insidiosum among unidentified fungal isolates from keratitis was 9/162 (5.5%) in phase 1. In phase 2, 4/102 cases (3.9%) of fungal keratitis were identified as P. insidiosum (January-February, 2014). Phylogenetic analysis of all 13 fungal isolates confirmed the identification of P. insidiosum. Corneal infiltrates exhibited hyphate edges, tentacle-like extensions, and dot-like infiltrates surrounding the main infiltrate. Response to topical 5% natamycin eye drops with or without oral antifungals was poor (penetrating keratoplasty: 9 and evisceration: 2) with a mean follow-up period of 82 days. CONCLUSIONS: P. insidiosum keratitis needs to be considered in the differential diagnosis of severe fungal keratitis. It can be identified using the zoospore formation method and confirmed by ITS DNA sequencing. Lack of response to currently used antifungal drugs calls for evaluation of newer drugs for medical therapy and consideration for early penetrating keratoplasty.

Re-appraisal of topical 1% voriconazole and 5% natamycin in the treatment of fungal keratitis in a randomised trial.

PURPOSE: To compare the efficacy of topical 1% voriconazole vs 5% natamycin for the treatment of fungal keratitis. METHODS: In a prospective, double-masked, randomised, controlled, registered clinical trial, 118 patients with fungal keratitis were treated using identical dosage schedule with either voriconazole (58) or natamycin (60) as inpatients for 7 days and followed up weekly. The outcome measures were percentage of patients with healed or resolving ulcer and final visual acuity at last follow-up (primary) and on day 7 (secondary) in each group. RESULTS: More patients (p=0.005) on natamycin (50/56, 89.2%) had healed or resolving ulcer compared with voriconazole (34/51, 66.6%) at last follow-up. The improvement in vision was marginally greater in patients in the natamycin group compared with the voriconazole group at day 7 (p=0.04) and significantly greater at final visit (p=0.01). In univariate analysis, drug, age and mean size of corneal infiltrate and epithelial defect had a significant effect on the final visual outcome. In multivariate analysis, the effect of drug (voriconazole vs natamycin, adjusted coefficient 0.27 (-0.04 to 0.57), p=0.09) was marginal while the effect of age and epithelial defect was significant (p<0.001 for both). In the group treated with natamycin, the final visual acuity was significantly better (p=0.005, Wilcoxon signed-rank test) in patients with Fusarium keratitis but not with Aspergillus keratitis (p=0.714, paired t test). CONCLUSIONS: When compared with voriconazole, natamycin was more effective in the treatment of fungal keratitis, especially Fusarium keratitis. TRIAL REGISTRATION NUMBER: Clinical Trial Registry India (2010/091/003041).

Use of topical colistin in multiple drug-resistant Pseudomonas aeruginosa bacterial keratitis.

PURPOSE: The aim of this study was to report the utility of topical colistin in multi-drug resistant Pseudomonas aeruginosa bacterial keratitis. METHODS: Retrospective interventional case series included 8 patients with culture-proven multi-drug resistant P. aeruginosa (MDR-PA) bacterial keratitis who presented from June 2011 to January 2012 and were treated with colistin 0.19% as monodrug therapy. Clinical/microbiological data were collected from medical records. All patients underwent microbiological corneal scraping. Intensive half-hourly therapy with broad-spectrum antibiotics was changed to colistin 0.19% when antibiotic sensitivity reports were available. The outcome was a "complete success" if resolution of infection occurred with scar formation without any subsequent recurrence up to 2 weeks and "partial success" if it also required a cyanacrylate glue application. The outcome was a "failure" if the patient required a therapeutic graft or if the infection could not be controlled and the eye needed evisceration. RESULTS: The mean age was 45 ± 16 years; the M:F ratio was 1:1. Seven patients had a history of ocular surgery. The mean size of the infiltrate was 15.41 ± 22.2 mm and was full thickness in 5 patients. Success was achieved in 7 out of 8 patients, and the infiltrate gradually decreased with resolution of infection in a mean duration of 30.5 ± 16 days. Complete and partial success were noted in 4 and 3 patients, respectively. The final visual acuity was 20/60 or better in 4 patients. One patient required a sclerocorneal patch graft. No complications of topical colistin were noticed. CONCLUSIONS: The early use of topical colistin 0.19% was found to be a safe and effective alternative in the management of multi-drug resistant P. aeruginosa bacterial keratitis.

Bacteremia during dacryocystorhinostomy: results of intra-operative blood cultures.

BACKGROUND: The aims of the study are to assess the prevalence of bacteremia during dacryocystorhinostomy (DCR) and to assess whether there is a need for post-operative prophylaxis. Prospective interventional study of 52 consecutive dacryocystorhinostomy performed in 50 patients over a period of 1 year from 2013 to 2014. Blood was drawn under strict aseptic conditions during two separate time points: fashioning of the nasal mucosal and creation of lacrimal sac flaps. The blood was inoculated into two blood culture bottles: the dual media as well as Columbia broth. Following withdrawal of blood, all patients received an intraoperative single dose of a cephalosporin antibiotic. Clean cases of primary acquired nasolacrimal duct obstructions (PANDO) without any sac discharge upon marsupialization (22%, 11/50) were not prescribed routine post-operative prophylaxis, whereas the remaining were prescribed oral antibiotics for 5 days. RESULTS: The mean age of patients was 41 years (range, 4-61 years). The most common diagnosis (70%, 35/50) was primary acquired nasolacrimal duct obstruction. Acute dacryocystitis was noted in 12% (6/50). External DCR was performed in 65% (34/52) and endoscopic DCR in 35% (18/52) of the cases. All the blood cultures were uniformly negative both in terms of abnormal physical changes in media as well subcultures; 22% (11/50) did not receive post-operative antibiotic prophylaxis. None of the patients developed any signs of wound infections. The anatomical and functional success rate was achieved in 98%. CONCLUSIONS: This study did not find any intraoperative bacteremia during dacryocystorhinostomy and that none had wound infection irrespective of post-operative prophylaxis.

Treatment outcomes and clinicomicrobiological characteristics of a protocol-based approach for neonatal endogenous endophthalmitis.

PURPOSE: To describe the outcomes and clinicomicrobiological profile of 11 years of a protocol-based management in neonatal endogenous endophthalmitis. METHODS: This was a retrospective interventional study of endogenous endophthalmitis in 31 eyes of 26 neonates. The protocol for active infection included systemic antimicrobials, vitreous and/or aqueous tap, and intravitreal antimicrobials under topical or general anesthesia along with core vitrectomy in selected cases. Blood, urine, umbilicus, aqueous, and vitreous samples underwent microbiological evaluation. Retinopathy of prematurity screening and treatment were done when indicated. Primary outcome was anatomic status assessed by comprehensive eye examination and by fundus photography whenever possible. RESULTS: Twenty-one of 26 babies (81%) were preterm. Two types of presentations included those with a fulminant appearance (24 eyes) and those with focal retinitis detected during routine screening (7 eyes). Vitreous culture was positive in 12/20 eyes (60%). Pseudomonas aeruginosa (8) was the most common isolate. Incorrect initial diagnosis was common. Treatment included intravitreal injections in 26 eyes, 10 of which also underwent vitrectomy. Twenty-four of the 26 patients (92%) received parenteral antimicrobials and 17 had evidence of systemic infection. All eyes with a fulminant presentation developed phthisis, while all focal fungal cases were salvaged. CONCLUSIONS: Neonatal endogenous endophthalmitis has 2 distinct presentations. Focal retinal infections have good visual and anatomical outcomes while fulminant nosocomial cases do poorly. Management under topical anesthesia can be an alternative strategy for sick babies that cannot undergo surgery under general anesthesia due to systemic morbidity. Awareness about early diagnostic signs may help early referral.

Stenotrophomonas maltophilia endogenous endophthalmitis: clinical presentation, antibiotic susceptibility, and outcomes.

OBJECTIVE: To describe clinical presentation, antibiotic susceptibility, and outcomes in patients with Stenotrophomonas maltophilia endogenous endophthalmitis. DESIGN: Retrospective case series. PARTICIPANTS: Four eyes of four patients with S. maltophilia endogenous endophthalmitis. METHODS: Retrospective chart review of culture-positive S. maltophilia endogenous endophthalmitis treated at L V Prasad Eye Institute, Hyderabad, India, between January 2007 and December 2012, was done. Collected information included demographic, clinical, and microbiology data. RESULTS: These four patients with S. maltophilia endogenous endophthalmitis cases accounted for 0.47% (4/836) of total bacterial endophthalmitis cases treated in this period. All patients were from a rural setting and younger than 40 years. Two of the four patients had a history of immune compromise or hospitalization. The visual acuity at presentation was less than 20/320 in all patients. Common presenting features were severe anterior and posterior segment inflammation and hypopyon. All patients underwent vitrectomy with injection of intravitreal antibiotics and dexamethasone. Direct microscopy of the vitreous sample was positive in all cases. All isolates were sensitive to fluoroquinolones and chloramphenicol; sensitivity to aminoglycosides and third-generation cephalosporins was highly variable. The final visual acuity was 20/80 or more in three patients. The time to presentation did not seem to influence the visual or anatomical outcome. CONCLUSION: S. maltophilia is a rare cause of endogenous endophthalmitis and usually occurs in young and apparently healthy individuals. Clinical presentation is moderate to severe, and recovery is variable. Fourth-generation fluoroquinolones and chloramphenicol were the most sensitive antibiotics against S. maltophilia in this series of patients.

Endophthalmitis after open globe injuries: changes in microbiological spectrum and isolate susceptibility patterns over 14 years.

BACKGROUND: The objective of this study was to evaluate the microbiologic spectrum and antimicrobial susceptibility of isolates in post-traumatic endophthalmitis and compare with our earlier published report. A retrospective review was conducted on 581 consecutive patients with culture-proven post-traumatic endophthalmitis at L. V. Prasad Eye Institute, India, from January 2006 to March 2013. FINDINGS: A total of 620 isolates from 581 patients were identified (565 bacteria and 55 fungi). The most common isolate was Bacillus spp. (106/620, 17.1%) closely followed by Streptococcus pneumoniae (105/620, 16.9%), and coagulase-negative Staphylococci (97/620, 15.6%). In our earlier report, the commonest bacteria included Streptococcus spp. (30/139, 21.6%) and gram-positive coagulase-negative micrococci (26/139, 18.7%). Gram-positive isolates were usually susceptible to vancomycin (98.2%). Gram-negative isolates were generally susceptible to gatifloxacin (92.9%), ofloxacin (89.4%), chloramphenicol (88.6%, Pseudomonas isolates were often resistant), amikacin (83.5%), and ceftazidime (77.2%). Fourteen years ago, the most sensitive antibiotic was ciprofloxacin for both gram-positive bacteria (95.12%) and gram-negative bacteria (100%). CONCLUSIONS: The microbiological spectrum of post-traumatic endophthalmitis has remained unchanged over the last 14 years, and Bacillus spp. continues as the most common infecting organism. Vancomycin is the drug of choice for empiric coverage of gram-positive bacteria. Susceptibility of gram-negative bacteria to commonly used antimicrobials (amikacin and ciprofloxacin) has decreased by 10% - 15% and to ceftazidime has increased by 10.5%.

The microbiological profile of lacrimal abscess: two decades of experience from a tertiary eye care center.

BACKGROUND: The aim of this study is to exclusively report the microbiological spectrum of lacrimal abscess and the antibiotic sensitivity patterns of the organisms. Retrospective interventional study on 112 eyes of 112 patients who presented to the ophthalmic plastic clinic of a tertiary eye care center over a period of 23 years from January 1990 to February 2013 with lacrimal abscess were reviewed for demographic and microbiological profile. The culture results, organisms isolated, and their antibiotic sensitivity were studied. RESULTS: The mean age at presentation was 37 years. The female to male ratio was 2:1. There was no significant difference in the laterality between the right and left eyes. Gram-positive organisms were the most commonly isolated accounting for 56.3% (63/112), and the commonest species isolated was Staphylococcus aureus in 25% (28/112) of the patients. Hemophilus influenzae was the commonest gram-negative isolate accounting for 30.2% of all the gram-negative isolates. Of the patients, 10.7% (12/112) showed no organisms on smear as well as sterile cultures. Gram-positive organisms were commonly sensitive to penicillins and vancomycin whereas gram-negative organisms were sensitive to quinolones and aminoglycosides. CONCLUSIONS: Gram-positive organisms are quite common as compared to gram-negative ones in cases of lacrimal abscess. The results of this study have significant bearing on the treatment of patients with lacrimal abscess.

Scleral buckle infections: microbiological spectrum and antimicrobial susceptibility.

BACKGROUND: The purpose of the present study was to evaluate the microbiological spectrum and antimicrobial susceptibility in patients with scleral buckle infection. Medical records of all the patients diagnosed as buckle infection at L. V. Prasad Eye Institute between July 1992 and June 2012 were reviewed in this non-comparative, consecutive, retrospective case series. FINDINGS: A total of 132 eyes of 132 patients underwent buckle explantation for buckle infection during the study period. The incidence of buckle infection at our institute during the study period was 0.2% (31 out of 15,022). A total of 124 isolates were identified from 102 positive cultures. The most common etiological agent isolated was Staphylococcus epidermidis (27/124, 21.77%) followed by Mycobacterium sp. (20/124, 16.13%) and Corynebacterium sp. (13/124, 10.48%). The most common gram negative bacilli identified was Pseudomonas aeruginosa (9/124, 7.26%). The median interval between scleral buckling surgery and onset of symptoms of local infection was 30 days. All eyes underwent buckle explantation and median time interval between primary SB surgery and explantation was 13 months. Recurrent retinal detachment was observed in two cases at 7 and 48 months, respectively, after buckle explantation. Gram positive, gram negative, and acid-fast organisms isolated from 2003 to 2012 were most commonly susceptible to vancomycin (100%), ciprofloxacin (100%), and amikacin (89%). Susceptibility to ciprofloxacin during the same time period was observed in 75% (15/20), 100% (13/13), and 87% (7/8) of gram positive, gram negative, and acid-fast isolates, respectively. CONCLUSION: Scleral buckle infection is relatively rare and has a delayed clinical presentation. It is most commonly caused by gram positive cocci. Based on the current antimicrobial susceptibility, ciprofloxacin can be used as empirical therapy in the management of scleral buckle infections.