Trends in bacterial and fungal keratitis in South India, 2002–2012

Lalitha, Prajna; Prajna, Namperumalsamy Venkatesh; Manoharan, Geetha; Srinivasan, Muthiah; Mascarenhas, Jeena; Das, Manoranjan; DSilva, Sean Socrates; Porco, Travis C.; Keenan, Jeremy D.

doi:10.1136/bjophthalmol-2014-305000

Cited by 68 publications

(73 citation statements)

References 16 publications

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“…Fungal keratitis represented 8.2% (N = 37) of the total positive cultures, consistent with other reports where the proportions ranged from 5–34%[3,17,23]. …”

Section: Discussionsupporting

confidence: 90%

“…While awaiting cultures, empiric treatment should be started immediately and the antibiotic chosen should be of sufficiently broad spectrum to cover likely pathogens based on local bacterial prevalence and antibiotic susceptibilities. [2] Since regional differences exist in the etiologies of bacterial keratitis[3,4], good local epidemiological data are needed for better empirical treatment of bacterial keratitis.…”

Section: Introductionmentioning

confidence: 99%

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Trends of Bacterial Keratitis Culture Isolates in Jerusalem; a 13- Years Analysis

et al. 2016

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PurposeTo describe the trends in pathogens and antibacterial resistance of corneal culture isolates in infectious keratitis during a period of 13 years at Hadassah-Hebrew University Medical Center.MethodsA Retrospective analysis of bacterial corneal isolates was performed during the months of January 2002 to December 2014 at Hadassah Hebrew University Medical Center. Demographics, microbiological data and antibiotic resistance and sensitivity were collected.ResultsA total of 943 corneal isolates were analyzed during a 13 year period. A total of 415 positive bacterial cultures and 37 positive fungal cultures were recovered, representing 48% of the total cultures. The Annual incidence was 34.78 ± 6.54 cases. The most common isolate was coagulase-negative staphylococcus (32%), which had a significant decrease in trend throughout the study period (APC = -8.1, p = 0.002). Methicillin-resistant Staphylococcus aureus (MRSA) appears to have a decrease trend (APC = -31.2, P = 0.5). There was an increase in the resistance trend of coagulase-negative staphylococci to penicillin (APC = 5.0, P = <0.001). None of the pathogens had developed any resistance to Vancomycin. (P = 0.88).ConclusionsCoagulase negative staphylococci were the predominant bacteria isolated from patients with keratitis. There was no significant change in the annual incidence of cases of bacterial keratitis seen over the past 13 years. Keratitis caused by MRSA appeared to decrease in contrast to the reported literature.

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“…Fungal keratitis represented 8.2% (N = 37) of the total positive cultures, consistent with other reports where the proportions ranged from 5–34%[3,17,23]. …”

Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Trends of Bacterial Keratitis Culture Isolates in Jerusalem; a 13- Years Analysis

et al. 2016

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“…At Aravind Eye Hospital in India, for example, 38% of corneal scrapings from eyes with presumed infectious keratitis tested negative on both culture and smear between 2002 and 2012. 105 Next Generation Sequencing (NGS) may improve on the diagnostic accuracy of infectious keratitis, particularly for organisms that are difficult to culture by conventional methods such as atypical or anaerobic bacteria. 106 NGS can detect more organisms that traditional culture techniques, and provide us with large volumes of information about the microbiome of the ocular surface.…”

Section: Future Directionsmentioning

confidence: 99%

Update on the Management of Infectious Keratitis

2017

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Infectious keratitis is a major global cause of visual impairment and blindness, often affecting marginalized populations. Proper diagnosis of the causative organism is critical, and while culture remains the prevailing diagnostic tool, newer techniques such as in vivo confocal microscopy are helpful for diagnosing fungal keratitis and Acanthameoba. Next generation sequencing holds the potential for early and accurate diagnosis even for organisms that are difficult to culture by conventional methods. Topical antibiotics remain the best treatment for bacterial keratitis, and a recent review found all commonly prescribed topical antibiotics to be equally effective. However outcomes remain poor secondary to corneal melting, scarring and perforation. Adjuvant therapies aimed at reducing the immune response responsible for much of the morbidity associated with keratitis include topical corticosteroids. The large, randomized controlled Steroids for Corneal Ulcers trial found that while steroids provided no significant improvement overall, they did appear beneficial for ulcers that were central, deep or large, non-Nocardia or classically invasive P. aeruginosa, patients with low baseline vision, and when started early after the initiation of antibiotics. Fungal ulcers often have worse clinical outcomes than bacterial ulcers, with no new treatments since the 1960’s when topical natamycin was introduced. The randomized controlled Mycotic Ulcer Treatment Trial showed a benefit of topical natamycin over topical voriconazole for fungal keratitis, particularly among those caused by Fusarium. The second Mycotic Ulcer Treatment Trial showed that oral voriconazole did not improve outcomes overall although there may have been some effect among Fusarium ulcers. Given an increase in non-serious adverse events the authors concluded that they could not recommend oral voriconazole at this time. Viral keratitis differs from bacterial and fungal cases in that is often recurrent and is common in developed countries. The first Herpetic Eye Disease Study (HEDS) showed a significant benefit of topical corticosteroids and oral acyclovir for stromal keratitis. HEDS II showed that oral acyclovir decreased the recurrence of any type of HSV keratitis by approximately half. Future strategies to reduce the morbidity associated with infectious keratitis are likely to be multidimensional with adjuvant therapies aimed at modifying the immune response to infection holding the greatest potential to improve clinical outcomes.

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“…In these cases, microbiological techniques such as culture and light microscopy can aid in diagnosis but they do not offer a high diagnostic accuracy. Culture-positivity rates in MK vary widely, from 40% to 73% in different settings, most likely because of the small size of corneal-scrape samples, prior antimicrobial treatment inhibiting microbial growth, and the fastidious nature of some organisms requiring special growth media (e.g., fungi and Acanthamoeba ) 4, 5, 6, 7. Direct visualization of fungal filaments or Acanthamoeba cysts in corneal scrapings using light microscopy can give a higher detection rate when compared with culture alone, 8 but it relies on the availability of trained, experienced observers who may not be present in some health care settings.…”

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confidence: 99%

Prospective Study of the Diagnostic Accuracy of the In Vivo Laser Scanning Confocal Microscope for Severe Microbial Keratitis

et al. 2016

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PurposeTo determine the diagnostic accuracy of in vivo confocal microscopy (IVCM) for moderate to severe microbial keratitis (MK).DesignDouble-masked prospective cohort study.ParticipantsConsecutive patients presenting to Aravind Eye Hospital, Madurai, India, between February 2012 and February 2013 with MK (diameter ≥3 mm, excluding descemetocele, perforation, or herpetic keratitis).MethodsFollowing examination, the corneal ulcer was scanned by IVCM (HRT3/RCM, Heidelberg Engineering, Heidelberg, Germany). Images were graded for the presence or absence of fungal hyphae or Acanthamoeba cysts by the confocal microscopist who performed the scan (masked to microbial diagnosis) and 4 other experienced confocal graders (masked to clinical features and microbiology). The regrading of the shuffled image set was performed by 3 graders, 3 weeks later. Corneal-scrape samples were collected for microscopy and culture.Main Outcome MeasuresThe main outcome measures were sensitivity, specificity, and positive and negative predictive values of IVCM compared with those of a reference standard of positive culture or light microscopy. Sensitivities and specificities for multiple graders were pooled and 95% confidence intervals calculated using a bivariate random-effects regression model.ResultsThe study enrolled 239 patients with MK. Fungal infection was detected in 176 (74%) and Acanthamoeba in 17 (7%) by microbiological methods. IVCM had an overall pooled (5 graders) sensitivity of 85.7% (95% confidence interval [CI]: 82.2%–88.6%) and pooled specificity of 81.4% (95% CI: 76.0%–85.9%) for fungal filament detection. For Acanthamoeba, the pooled sensitivity was 88.2% (95% CI: 76.2%–94.6%) and pooled specificity was 98.2% (95% CI: 94.9%–99.3%). Intergrader agreement was good: κ was 0.88 for definite fungus; κ was 0.72 for definite Acanthamoeba. Intragrader repeatability was high for both definite fungus (κ: 0.88–0.95) and definite Acanthamoeba classification (κ: 0.63–0.90). IVCM images from 11 patients were considered by all 5 graders to have a specific organism present (10 fungus, 1 Acanthamoeba) but had negative results via culture and light microscopy.ConclusionsLaser scanning IVCM performed with experienced confocal graders has high sensitivity, specificity, and test reproducibility for detecting fungal filaments and Acanthamoeba cysts in moderate to large corneal ulcers in India. This imaging modality was particularly useful for detecting organisms in deep ulcers in which culture and light microscopy results were negative.

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Trends in bacterial and fungal keratitis in South India, 2002–2012

Abstract: At a tertiary eye care centre in South India, there has been a reduction in the numbers of smear-positive bacterial keratitis over the past 11 years. This decline likely reflects economic development in India and increased access to antibiotics.

Cited by 68 publications

References 16 publications

Trends of Bacterial Keratitis Culture Isolates in Jerusalem; a 13- Years Analysis

Trends of Bacterial Keratitis Culture Isolates in Jerusalem; a 13- Years Analysis

Update on the Management of Infectious Keratitis

Prospective Study of the Diagnostic Accuracy of the In Vivo Laser Scanning Confocal Microscope for Severe Microbial Keratitis

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