Aetiology of suppurative corneal ulcers in Ghana and south India, and epidemiology of fungal keratitis

Fungal keratitis: An overview of clinical and laboratory aspects

Mycotic keratitis or keratomycosis is a fungal infection with global distribution. The dominant aetiology of this disease varies based on geographical origin, socioeconomic status, and climatic condition. Generally, Aspergillus spp. and Fusarium spp. are common in tropical and subtropical regions and Candida spp. are dominant in temperate areas. Demonstration of fungal elements in microscopic examination besides the isolation of fungi in culture is the gold standard of laboratory diagnosis. As the culture is a time-consuming procedure, other approaches such as in vivo confocal microscopy which produces real-time imaging of corneal tissue and molecular techniques have been developed to facilitate rapid diagnosis of fungal keratitis. The first choice of treatment is topical natamycin, although topical amphotericin B is the best choice for Aspergillus and Candida keratitis. Regarding the diversity of fungal aetiology and the emergence of drug resistance in some genera and species, proper identification using molecular methods and antifungal susceptibility testing could provide useful data. Furthermore, as the better efficacy of combination therapy in comparison to monotherapy is reported, in vitro determination of interactions between various drugs seem informative. This review aims to provide a general and updated view on the aetiology, risk factors, epidemiology, clinical and laboratory diagnosis, and management of fungal keratitis.

Bilateral Candida keratitis in an HIV patient with asymptomatic genitourinary candidiasis in Uganda

A 35-year-old male presented with Candida keratitis in the left eye. He was HIV positive with a CD4 of 352 cells/µL. The eye quickly deteriorated, despite intensive antifungal treatment and was eviscerated. Five months later, he re-presented with Candida keratitis in his right eye. A focal source of Candida infection was suspected and a urine culture identified Candida spp, despite being asymptomatic for genitourinary candidiasis. He was subsequently treated with good outcome (max. 75 words)

Mincle in the innate immune response of mice fungal keratitis

AIM

To investigate how macrophage inducible C-type lectin (Mincle) influences inflammation in mice fungal keratitis induced by Aspergillus fumigatus (A. fumigatus).

METHODS

C57BL/6 mice were infected with A. fumigatus after pretreated with Mincle agonist TDB or Mincle neutralizing antibody (MincleAb), taking DMSO or IgG as control group respectively. The cornea lesions were monitored with slit-lamp microscope and evaluated by clinical score. Mincle expression was assessed using reverse transcription-ploymerase chain reaction (RT-PCR) and immunostaining. The expression of cytokines (IL-1β, TNF-α and IL-6) chemokines (CXCL-1 and MIP-2) was determined by RT-PCR and ELISA. Neutrophil infiltration was observed by immunostaining. The levels of nitric oxide (NO) generated by corneas were tested by Griess reaction.

RESULTS

Mincle mRNA and protein levels were higher in infected corneas than normal corneas of C57BL/6 mice, saving clinical scores revealed differences. When pretreated with Mincle agonist TDB, the mRNA and protein levels of IL-1β, TNF-α and IL-6 in infected corneas were significantly increased compared with the control group (P<0.01). Results of the counterpart in corneas pretreated with Mincle neutralizing antibody was decreased consistently (P<0.01). Expression of CXCL1 and MIP-2 mRNA levels were up-regulated in TDB group and down-regulated in MincleAb group (P<0.01), coincide with neutrophil aggregation degree in corneas showed by immunostaining. As for the concentration of NO, it was promoted in TDB group compared with DMSO control group, and decreased in MincleAb group compared with IgG control group.

CONCLUSION

Mincle plays a dual role in mice fungal keratitis. It participates in the innate immune system by enhancing inflammation. What's more, Mincle can mediate cytotoxic effects by regulating the formation of NO.

Microplasma Jet Arrays as a Therapeutic Choice for Fungal Keratitis

The clinical impact of microplasma jets on rabbit eyes infected by Candida albicans has been investigated. Arrays of such jets produce low-temperature plasma micro-columns suitable for ophthalmic therapeutics and fungal infections, in particular, and the technology is capable of being scaled to surface areas of at least 10 cm². Keratitis was induced in the right central corneas of rabbits, whereas the left eyes served as a normal group. The rabbits were divided into the plasma non-treated group (control) and plasma treatment group. Histologic analyses of both groups showed marked reductions in the thickness, angiogenesis, and opacity of all rabbit corneas following plasma treatment. Indeed, for treatment times beyond 14 days, infected eyes exhibited no significant differences from the normal group. Healing of rabbit eyes infected by Candida albicans apparently proceeds by disrupting corneal epithelial proliferation, and by reducing fibrotic changes in the stroma. This study demonstrates that low-temperature plasma jets are remarkably effective in healing Candida albicans-infected corneas, thereby providing a promising medical treatment option for keratitis.

Keratitis secondary to Fusarium spp. in Spain 2012-2014

OBJECTIVE

To describe the clinical-epidemiological characteristics of a case series of fungal keratitis associated with Fusarium spp.., in Spain during the years 2012 to 2014.

METHODS

A retrospective study of a case series was conducted on a systematic random sample of 10% of patients identified in Health Centres of provincial capitals (n=250). The centres were asked whether they had been presented with cases of Fusarium spp. keratitis characterised by microbiological methods. Of the 23 centres that responded, 14 had detected cases, with 13 of them accepting to participate, and 11 of them completing the study. The latter being sent a previously validated questionnaire. The variables analysed were: age, gender, habitual residence, profession, disease and medical history (previous systemic and ocular diseases, previous eye surgeries), and their outcomes.

RESULTS

The response rate was 92%, identifying 23 cases of Fusarium spp.. of which 21 (91.3%) of them lived in urban areas. The professions most affected by the disease included chefs, administrative, and technical, with 13 cases (56.5%). The treatment guidelines established to confirm the infection showed the combined use of topical antibiotics associated with antiviral and/or antifungal agents. The use of contact lenses (86.9%) was the main risk factor.

DISCUSSION

This study showed that this is a rare disease in Spain, but that a large percentage of people who present with the disease are resident in urban areas, and they work in closed environments, focusing attention on microtraumas caused by use of contact lenses.

ROS-induced Oxidative Injury involved in Pathogenesis of Fungal Keratitis via p38 MAPK Activation

This study was to explore the mechanism by which reactive oxygen species (ROS)-induced oxidative stress involved in the pathogenesis of fungal keratitis using an in vivo experimental keratitis mouse model and an in vitro culture model of human corneal epithelial cells (HCECs). Compared to normal control mice and HCECs, ROS production was markedly increased in fungal corneas and HCECs exposed to Candida albicans, accompanied by p38 mitogen-activated protein kinases (MAPK) activation. Increased products of oxidative markers, malondialdehyde (MDA), 4–hydroxynonenal (HNE), mitochondria DNA 8-OHdG and aconitase-2 were observed in fungal infected corneas and HCECs. Fungal infection also increased the mRNA expression and protein production of heme oxygenase-1 (HMOX1) and cyclooxygenase-2 (COX2), with suppressed levels of antioxidant enzymes, superoxide dismutase-1 (SOD1), glutathione peroxidase-1 (GPx1) and peroxiredoxin-4 (PRDX4). Interestingly, the levels of ROS, oxidative markers and oxygenases were significantly reduced by co-cultured p38 inhibitor SB203580. Furthermore, SB203580 restored the levels of antioxidant enzymes suppressed by fungus. Our findings demonstrated for the first time that ROS-induced oxidative injury is involved in pathogenesis of fungal keratitis via p38 MAPK pathway, suggesting the novel therapeutic targets for the potential treatment of fungal keratitis.

Role of Pattern Recognition Receptors in the Modulation of Antimicrobial Peptide Expression in the Corneal Epithelial Innate Response to F. solani

Purpose

Fusarium solani (F. solani) keratitis is a potentially sight-threatening fungal infection of the cornea. Antimicrobial peptides (AMPs), such as human β-defensins (hBDs) and cathelicidins, essential components of the immune system, likely have a protective role against F. solani keratitis. We examined the role of pattern recognition receptors (PRRs), Dectin-1, and TLR2 in F. solani–induced modulation of AMP expression in vitro.

Methods

Human corneal epithelial cells (HCECs) were exposed to heat-inactivated F. solani or pathogen-associated molecular patterns (PAMPs) of F. solani (Zymosan or Zymosan Depleted) for 6, 12, or 24 hours following which AMP mRNA and protein levels were determined. Involvement of TLR2 and Dectin-1 was confirmed by using siRNA knock-down (TLR2 and Dectin-1) or chemical inhibitor BAY 61-3606 (Dectin-1). The functional significance of AMP upregulation was tested using culture supernatant from F. solani or PAMP-treated HCECs against F. solani in the presence of hBD2 or LL37 neutralizing antibody.

Results

We confirm that HCECs express Dectin-1 and TLR2. HCECs demonstrated upregulation of AMPs hBD2 and cathelicidin LL37 following exposure to heat-inactivated F. solani or PAMPs. TLR2 and Dectin-1 knockdown and BAY 61-3606 treatment decreased AMP mRNA upregulation confirming PRR involvement. The culture supernatant from F. solani or PAMP-treated HCECs showed substantial killing of F. solani and hBD2 or LL37 neutralizing antibody significantly decreased this effect implicating involvement of these AMPs.

Conclusions

These findings demonstrate that Dectin-1 and TLR2 have an important role in regulating F. solani-induced AMP expression in corneal epithelial cells.

Exophiala phaeomuriformis Fungal Keratitis: Case Report and In Vivo Confocal Microscopy Findings

PURPOSE

Corneal infections, particularly fungal keratitis due to rare fungal species, pose a diagnostic and therapeutic challenge because of difficulty in identification and varying susceptibility profiles. In this study, we report the first case of fungal keratitis because of Exophiala phaeomuriformis.

METHODS

We report the clinical findings and microbial identification techniques of a case of fungal keratitis due to E. phaeomuriformis. An 84-year-old woman presented with redness, pain, and itching in the left eye for 2 weeks. Slit-lamp biomicroscopy revealed one broken suture from previous penetrating keratoplasty (PKP), black infiltrates at the 4-o'clock position, without an overlying epithelial defect and hypopyon. Microbial identification was based cultures on Sabouraud dextrose agar and DNA sequencing and correlations to laser in vivo confocal microscopy (IVCM; Heidelberg Retinal Tomograph 3/Rostock Cornea Module, Heidelberg Engineering) and multiphoton microscopy (Ultima Microscope; Prairie Technologies) images.

RESULTS

Slit-lamp biomicroscopy revealed one broken suture from previous PKP, black infiltrates at the 4-o'clock position, without an overlying epithelial defect and hypopyon. Based on a clinical suspicion of fungal keratitis, antifungals and fortified antibiotics were started. However, the patient did not respond to therapy and required urgent PKP. After surgery, the patient was maintained on topical and systemic voriconazole and also topical 2% cyclosporine for 5 months because of possibility of scleral involvement noticed during surgery. At the end of the treatment period, her vision improved from hand motion to 20/40, with no recurrence observed in a follow-up period of 1 year. Results of diagnostic tests were supported by fungal elements in stroma on IVCM. Culture from the infiltrate grew black yeast. DNA sequencing led to the diagnosis of E. phaeomuriformis keratitis. Antifungal susceptibility testing revealed sensitivity to voriconazole.

CONCLUSION

This is, to our knowledge, the first reported case of E. phaeomuriformis fungal keratitis. Diagnostic testing included slit-lamp biomicroscopy, which revealed pigmented infiltrates, culture plates grew black yeast, microscopy showed branched fungal hyphae with budding conidia, and physiological features showed tolerance to high temperatures, nitrate assimilation, and ribosomal DNA sequencing. Collectively, these tests demonstrate unique features seen for this microorganism. High suspicion should be kept with pigmented infiltrates and with dark yeast on culture plates. Prompt and aggressive medical management with voriconazole or therapeutic PKP in nonresponsive cases is essential to prevent irreversible loss of vision.

Fungal Keratitis Associated With Airborne Organic Debris and Soft Contacts Lenses: Case Reports and Review of the Literature

OBJECTIVES

To report two cases of fungal keratitis in soft contact lens wearers who were exposed to environmental mold.

METHODS

Case reports, with review of the relevant literature.

RESULTS

Two otherwise healthy middle-aged women who were soft contact lens wearers developed fungal keratitis about 1 week after heavy exposure to environmental mold. Culture results showed Aspergillus from one patient and the unusual combination of Trichoderma and Penicillium from the other. Both were treated with topical natamycin, topical fluoroquinolone antibiotic prophylaxis, and periodic ulcer debridement. After many weeks of treatment, both ulcers healed with subsequent scarring. Because the ulcers were located in the peripheral cornea in both cases, excellent final visual acuities were achieved. Fungal keratitis cases like these are rarely seen at our referral clinic, which is located in the temperate climate of northeastern Indiana.

CONCLUSIONS

In addition to the usual recommended contact lens care guidelines, it may be prudent for eye care providers to warn patients against wearing their contact lenses in situations likely to result in heavy exposure to organic matter or, at the very least, to wear tight-fitting goggles for eye protection.

Conjunctival Microbial Flora in Ocular Stevens-Johnson Syndrome Sequelae Patients at a Tertiary Eye Care Center

PURPOSE

To evaluate the conjunctival microbial flora in cases of ocular Stevens-Johnson Syndrome (SJS) in a tertiary eye care center.

METHODS

This prospective study comprised 176 eyes of 88 patients with ocular SJS compared with 124 eyes of normal subjects. The conjunctival swabs were collected and sent for microbiological analysis for bacterial isolation and antibiotic sensitivity examination. The type of bacteria isolated and its antibiotic sensitivity pattern were studied.

RESULTS

Of 176 eyes, 104 (59%) had positive cultures for bacteria in cases of SJS and 16 (12.9%) had positive culture in the control group, the difference being statistically significant (P = 0.001). In the SJS group, 14 different types of bacterial isolates were identified. The most common isolate was coagulase-negative staphylococci (CNS) (30/104, 28.8%) followed by Corynebacteria species (35/104, 33.6%) and Staphylococcus aureus (19/104, 18.2%). More than 1 bacteria were isolated in 7 eyes (6.7%). Most of the isolates showed resistance to ciprofloxacin with no resistance to gatifloxacin and moxifloxacin. In the control group, only 2 bacteria were isolated, which included CNS (14/16, 87.5%) and Streptococcus pneumoniae (2/16, 12.5%). CNS showed resistance to ciprofloxacin, and S. pneumoniae was resistant to tobramycin and gentamycin.

CONCLUSIONS

Ocular SJS is associated with alteration of the normal microbial flora residing in the conjunctival sac. The study of which is vital in cases of infection in these eyes with compromised ocular surface. Mixed flora are seen more often in cases of ocular SJS as compared with controls.

Microbiological profile of corneal ulcer cases diagnosed in a tertiary care ophthalmological institute in Nepal

Background

Corneal ulcer, a major cause of monocular blindness in developing countries has consistently been listed as the major cause of blindness and visual disability in many of the developing nations in Asia, Africa and the Middle East, ranking second only to cataract. This study was carried out to determine the microbiological profile of corneal ulcer cases diagnosed among patients visiting Tilganga Institute of Ophthalmology (TIO), Nepal.

Methods

A total of 101 corneal scrapping samples were tested for routine culture and antibiotic susceptibility at the pathology department of TIO Nepal from April to October 2014. Microorganisms were identified by using standard microbiological procedures following the manual of American Society for Microbiology (ASM) and their antibiotic susceptibility test, performed by Kirby-Bauer disc diffusion method in conformity with the CLSI guideline.

Results

Out of 101 samples analyzed, 44.6% (45/101) showed positive growth with bacterial isolates i.e., 56% (25/45), more prevalent than fungus i.e., 44% (20/45). Among bacteria Streptococcus pneumoniae (31.1%, N = 14) was isolated in highest number whereas Fusarium (13.4%, N = 6) was the most common fungus species. Pseudomonas aeruginosa was the only Gram negative bacteria isolated from corneal ulcer cases. All bacterial isolates were found to be susceptible to the quinolone group of antibiotics (moxifloxacin followed by ofloxacin and ciprofloxacin).

Conclusions

These findings showcase the current trend in the microbiological etiology of corneal ulcer in Nepal, which have important public health implications for the treatment as well as prevention of corneal ulceration in the developing world.

A comparative, retrospective, observational study of the clinical and microbiological profiles of post-penetrating keratoplasty keratitis

Infectious keratitis after penetrating keratoplasty (PK) is a devastating condition that may result in graft failure and poor visual outcome. In this study, we retrospectively reviewed the medical records of patients who underwent PK between 2009 and 2014, and recorded those who developed infectious keratitis. We compared the predisposing factors and organisms isolated to those identified in our previous study, conducted between 1989 and 1994. The incidence of post-PK infectious keratitis decreased from 11.6% (41 out of 354 cases, 1989–1994) to 6.5% (9 out of 138 cases, 2009–2014). Graft epithelial defect and suture-related problems remained the leading two risk factors of infectious keratitis after PK. Gram-positive and Gram-negative bacterial infection decreased from 58.5% and 46.3% to 11.1% and 22.2%, respectively (P = 0.023 and P = 0.271). In contrast, fungus infection increased from 9.8% to 66.7% (P = 0.001); fungi have become the major pathogen for post-PK infectious keratitis. In conclusion, while the incidence of post-PK infectious keratitis has decreased over time, the number and frequency of fungal infections have significantly increased in the recent study period. Clinicians should be aware of the shifting trend in pathogens involved in post-PK infectious keratitis.

Altered Patterns of Fungal Keratitis at a London Ophthalmic Referral Hospital: An Eight-Year Retrospective Observational Study

PURPOSE

In previous studies of fungal keratitis (FK) from temperate countries, yeasts were the predominant isolates, with ocular surface disease (OSD) being the leading risk factor. Since the 2005-2006 outbreak of contact lens (CL)-associated Fusarium keratitis, there may have been a rise in CL-associated filamentary FK in the United Kingdom. This retrospective case series investigated the patterns of FK from 2007 to 2014. We compared these to 1994-2006 data from the same hospital.

DESIGN

Retrospective observational study.

METHODS

All cases of FK presenting to Moorfields Eye Hospital between 2007 and 2014 were identified. The definition of FK was either a fungal organism isolated by culture or fungal structures identified by light microscopy (LM) of scrape material, histopathology, or in vivo corneal confocal microscopy (IVCM). Main outcome measure was cases of FK per year.

RESULTS

A total of 112 patients had confirmed FK. Median age was 47.2 years. Between 2007 and 2014, there was an increase in annual numbers of FK (Poisson regression, P = .0001). FK was confirmed using various modalities: 79 (70.5%) by positive culture, 16 (14.3%) by LM, and 61 (54.5%) by IVCM. Seventy-eight patients (69.6%) were diagnosed with filamentary fungus alone, 28 (25%) with yeast alone, and 6 (5.4%) with mixed filamentary and yeast infections. This represents an increase in the proportion of filamentary fungal infections from the pre-2007 data. Filamentary fungal and yeast infections were associated with CL use and OSD, respectively.

CONCLUSIONS

The number of FK cases has increased. This increase is due to CL-associated filamentary FK. Clinicians should be aware of these changes, which warrant epidemiologic investigations to identify modifiable risk factors.

Altered Patterns of Fungal Keratitis at a London Ophthalmic Referral Hospital: An Eight-Year Retrospective Observational Study

PURPOSE

In previous studies of fungal keratitis (FK) from temperate countries, yeasts were the predominant isolates, with ocular surface disease (OSD) being the leading risk factor. Since the 2005-2006 outbreak of contact lens (CL)-associated Fusarium keratitis, there may have been a rise in CL-associated filamentary FK in the United Kingdom. This retrospective case series investigated the patterns of FK from 2007 to 2014. We compared these to 1994-2006 data from the same hospital.

DESIGN

Retrospective observational study.

METHODS

All cases of FK presenting to Moorfields Eye Hospital between 2007 and 2014 were identified. The definition of FK was either a fungal organism isolated by culture or fungal structures identified by light microscopy (LM) of scrape material, histopathology, or in vivo corneal confocal microscopy (IVCM). Main outcome measure was cases of FK per year.

RESULTS

A total of 112 patients had confirmed FK. Median age was 47.2 years. Between 2007 and 2014, there was an increase in annual numbers of FK (Poisson regression, P = .0001). FK was confirmed using various modalities: 79 (70.5%) by positive culture, 16 (14.3%) by LM, and 61 (54.5%) by IVCM. Seventy-eight patients (69.6%) were diagnosed with filamentary fungus alone, 28 (25%) with yeast alone, and 6 (5.4%) with mixed filamentary and yeast infections. This represents an increase in the proportion of filamentary fungal infections from the pre-2007 data. Filamentary fungal and yeast infections were associated with CL use and OSD, respectively.

CONCLUSIONS

The number of FK cases has increased. This increase is due to CL-associated filamentary FK. Clinicians should be aware of these changes, which warrant epidemiologic investigations to identify modifiable risk factors.

Corneal Phaeohyphomycosis Caused by Bipolaris hawaiiensis

Purpose

To report a rare case of keratitis infected by Bipolaris hawaiiensis.

Methods

A patient who was diagnosed as fungal keratitis caused by B. hawaiiensis was retrospectively reviewed for history, clinical characteristics, risk factors, laboratory findings, treatments, and outcomes.

Results

A 63-year-old man with a history of trauma and saw dust in the left eye presented with a corneal ulcer. Eye examination revealed whitish infiltration with a feathery edge and small brownish deposits in the anterior stroma of the left cornea. Numerous septate hyphal fragments were detected in a corneal specimen, and nucleotide sequence analysis identified B. hawaiiensis. Treatment was started with 5% natamycin eyedrops and oral itraconazole. Subsequently, a corneal plaque developed which did not respond to medication and debridement. The patient underwent therapeutic penetrating keratoplasty.

Conclusions

B. hawaiiensis is a rare cause of corneal phaeohyphomycosis. A brownish pigmented infiltration is an important diagnostic clue, however microbiologic studies are required to obtain a definite diagnosis. Although antifungal medication and debridement are the mainstay of most corneal fungal infection, therapeutic penetrating keratoplasty can prevent morbidity related to this fungal infection.

Geographic Disparities in the Etiology of Bacterial and Fungal Keratitis in the United States of America

Infectious keratitis is a serious cause of vision loss. Proper treatment of infectious keratitis requires antimicrobials that target the organism responsible for a patient's ulcer. The frequency of infection by a given organism varies by location. We examined the literature to determine geographic disparities in the etiology of bacterial and fungal keratitis in the United States of America. Bacterial keratitis makes up a greater proportion of cases in northern locations, and fungal keratitis increases in prevalence in southern locations. Gram-negative organisms make up a greater proportion of bacterial keratitis in southern locations when compared to northern locations.

Time-dependent matrix metalloproteinases and tissue inhibitor of metalloproteinases expression change in fusarium solani keratitis

AIM

To investigate matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) expression during the progress of fusarium solani (F.solani) keratitis in a rat model.

METHODS

A rat model of F.solani keratitis was produced using corneal scarification and a hand-made contact lens. MMPs and TIMPs expressiond were explored in this rat model of F.solani keratitis using real-time polymerase chain reaction (PCR) and DIF. GM6001 (400 µmol/mL) was used to treat infected corneas. The keratitis duration, amount and area of corneal neovascularization (CNV) were evaluated.

RESULTS

MMP-3 expression was 66.3 times higher in infected corneas compared to normal corneas. MMP-8, -9, and -13 expressions were significantly upregulated in the mid-period of the infection, with infected-to-normal ratios of 4.03, 39.86, and 5.94, respectively. MMP-2 and -7 expressions increased in the late period, with the infected-to-normal ratios of 5.94 and 16.22, respectively. TIMP-1 expression was upregulated in the early period, and it was 43.17 times higher in infected compared to normal corneas, but TIMP-2, -3, and -4 expressions were mildly downregulated or unchanged. The results of DIF were consistent with the result of real-time PCR. GM6001, a MMPs inhibitor, decreased the duration of F.solani infection and the amount and area of CNV.

CONCLUSION

MMPs and TIMPs contributed into the progress of F.solani keratitis.

Corneal infection in Shandong peninsula of China: a 10-year retrospective study on 578 cases

AIM

To determine the epidemiological characteristics, clinical signs, laboratory findings, and outcomes in patients with corneal infection in Shandong peninsula of China.

METHODS

The medical records of 578 inpatients (578 eyes) with corneal infection were reviewed retrospectively for demographic characteristics, risk factors, seasonal variation, clinical signs, laboratory findings, and treatment strategy. Patient history, ocular examination findings using slit-lamp biomicroscopy, laboratory findings resulted from microbiological cultures, and treatment.

RESULTS

Fungal keratitis constituted 58.48% of cases of infectious keratitis among the inpatients, followed by herpes simplex keratitis (20.76%), bacterial keratitis (19.03%) and acanthamoeba keratitis (1.73%). The most common risk factor was corneal trauma (71.80%). The direct microscopic examination (338 cases) using potassium hydroxide (KOH) wet mounts was positive in 296 cases (87.57%). Among the 298 fungal culture-positive cases, Fusarium species were the most common isolates (70.47%). A total of 517 cases (89.45%) received surgical intervention, including 255 (44.12%) cases of penetrating keratoplasty, 74 (12.80%) cases of lamellar keratoplasty which has become increasingly popular, and 77 cases (13.32%) of evisceration or enucleation.

CONCLUSION

At present, infectious keratitis is a primary corneal disease causing blindness in China. With Fusarium species being the most commonly identified pathogens, fungal keratitis is the leading cause of severe infectious corneal ulcers in Shandong peninsula of China.

Microbial Profile of Corneal Ulcers in a Tertiary Care Hospital in South India

PURPOSE

To identify the prevalence and microbial profile of infectious keratitis in a tertiary eye care hospital, and to test for the in vitro antimicrobial resistance of the bacterial isolates.

METHODS

A total of 312 patients presenting to a tertiary eye care hospital with infected corneal ulcer were enrolled in this study. Their socio-demographic data and risk factors were recorded. Corneal scrapings collected from the edge of the ulcer were processed for direct gram stain and KOH mount. Culture was recovered on blood agar, chocolate agar, MacConkey agar and Sabouraud's dextrose (SDA) agar in multiple C shaped streaks. After overnight incubation, bacterial culture was followed by standard biochemical tests and antimicrobial sensitivity according to the clinical and laboratory standards institute (CLSI) guidelines. Inoculated SDA was inspected daily for up to 10 days and the growth was identified by its colony morphology, pigment production and lacto-phenol cotton blue mount examination.

RESULTS

Of 312 patients, a microbial etiology was established in 117 cases (37.5%). Of these, 72 (61.5%) were male. The age range of 41-60 years was the most affected group. Of 117 positive cases, 52 (44.5%) were bacterial, 58 (49.5%) were fungal and 7 (6%) patients showed mixed bacterial and fungal infection. The most common isolated fungus was Fusarium which was detected in 36 (31%) cases, followed by Aspergillus spp in 13 (11%) subjects. Staphylococcus aureus was the most common isolated bacteria. All Gram positive cocci were susceptible to vancomycin followed by gatifloxacin, whereas all Gram negative bacilli were susceptible to gatifloxacin.

CONCLUSION

Routine microbiological examination of patients with corneal ulcer is necessary in order to analyze and compare the changing trends of the etiology and their susceptibility patterns.

Study of Pathogens of Fungal Keratitis and the Sensitivity of Pathogenic Fungi to Therapeutic Agents with the Disk Diffusion Method

PURPOSE/AIM OF THE STUDY

To identify the causative fungi of fungal keratitis, test their susceptibility to antifungal agents with the disk diffusion method and study the relationship between the organisms, the inhibition zones and the clinical outcomes.

MATERIALS AND METHODS

535 patients with fungal keratitis in one eye were included in this study. Pathogenic fungi were isolated by corneal scraping, identified by fungal cultivation and subjected to drug sensitivity tests conducted with the disk diffusion method. The patients were treated initially with voriconazole, terbinafine and natamycin eye drops for one week. Further treatment continued using the most effective drug according to the drug sensitivity results. The patients were followed up every week until three months after cured. The inhibition zones of fungi cultured with voriconazole, terbinafine and natamycin were compared. The relationship between inhibition zones and organism, organism and treatment results measure, and each treatment results measure and inhibition zones were evaluated.

RESULTS

Of 535 patients, 53.84%, 19.25% and 26.91% were infected with Aspergillus, Fusarium and other fungi, respectively. Keratitis patients infected with Aspergillus keratitis had the worst outcome. The size of the inhibition zones of Aspergillus spp., Fusarium spp. and other fungal genera differed significantly in response to voriconazole, terbinafine and natamycin. The inhibition zone associated with natamycin correlated significantly with the clinical outcome of fungal keratitis (OR = 0.925), but no other such correlations were found for the other drugs tested.

CONCLUSIONS

Aspergillus and Fusarium were the predominant pathogenic genera causing fungal keratitis in our patients. Among the causative fungi, infections due to Aspergillus spp. were associated with the worst outcomes. The inhibition zones of fungal isolates in response to natamycin significantly correlated with the treatment outcomes of keratitis. Specifically, the smaller the natamycin inhibition zone, the lower the probability that the fungal keratitis had been eliminated.

Bacterial keratitis in a tertiary eye centre in Iran: a retrospective study

PURPOSE

To report the characteristics and laboratory findings of 182 patients with bacterial keratitis diagnosed at Farabi Eye Hospital in Tehran, Iran.

MATERIALS AND METHODS

In this retrospective study, data were collected on demographics, risk factors, location, size and depth of the ulcer, height of the hypopyon, uncorrected visual acuity, results of smear and culture tests, and antibiotic sensitivity of cultured bacteria.

RESULTS

There were 110 (60.4%) males and 72 (39.6%) females with an average age of 56.0 ± 2.3 years. Ocular trauma (17.6%) and positive history of corneal surgery (14.3%) were major risk factors. The mean age of contact lens users was 22.5 ± 7.7 years. Sixty patients (33%) used topical antibiotics, 21 (11.5%) patients utilized topical steroid, and 26 (14.3%) cases used both topical antibiotic and steroid at presentation. Culture results were, 81 (44.5%) cases were Gram-positive, 63 (34.6%) were Gram-negative, 10 (5.5%) were mixed bacteria and in 28 (15.4%) cases had detected growth. The isolated bacterial species from the corneal ulcers were less resistant to ceftazidime (6%) and amikacin (6%). The majority of patients were treated with medical therapy; however, 81 cases (44.5%) received at least one surgical procedure.

CONCLUSION

Among the patients with bacterial corneal ulcers, trauma was the most common risk factor. Over-the-counter antibiotic and steroid were commonly used in the majority of patients. The most common bacteria isolated were Gram-positives, and they were less resistant to ceftazidime and amikacin. Penetrating keratoplasty was the most common surgical procedure in patient who required surgery.

Levofloxacin and Tobramycin for Severe Bacterial Keratouveitis

PURPOSE

To report on clinical features and outcome of severe bacterial keratouveitis.

METHODS

Twenty patients with severe bacterial keratouveitis treated with topical tobramycin and levofloxacin and oral levofloxacin were included. Main outcome measures were ulcers location, bacterial isolates, risk factors, visual prognosis.

RESULTS

Centrally located ulcer/abscess was present in 65% of patients. Contact lens (CL) wear was the most common risk factor (70%). Bacterial isolates were observed in 58% of patients, none resistant to tobramycin and levofloxacin. Pseudomonas aeruginosa was found in 47% of positive cases and in 64% of CL wearers. After therapy, the mean visual acuity improved significantly (p < 0.0001), particularly in contact lens wearers (p = 0.04) and in patients younger than 60 years old (p < 0.001).

CONCLUSIONS

Pseudomonas aeruginosa is the most frequent cause of bacterial keratouveitis and CL wear the most common risk factor. Topical tobramycin and levofloxacin and oral levofloxacin are effective in the treatment of bacterial keratouveitis.

Pattern recognition receptors in microbial keratitis

Microbial keratitis is a significant cause of global visual impairment and blindness. Corneal infection can be caused by a wide variety of pathogens, each of which exhibits a range of mechanisms by which the immune system is activated. The complexity of the immune response to corneal infection is only now beginning to be elucidated. Crucial to the cornea's defences are the pattern-recognition receptors: Toll-like and Nod-like receptors and the subsequent activation of inflammatory pathways. These inflammatory pathways include the inflammasome and can lead to significant tissue destruction and corneal damage, with the potential for resultant blindness. Understanding the immune mechanisms behind this tissue destruction may enable improved identification of therapeutic targets to aid development of more specific therapies for reducing corneal damage in infectious keratitis. This review summarises current knowledge of pattern-recognition receptors and their downstream pathways in response to the major keratitis-causing organisms and alludes to potential therapeutic approaches that could alleviate corneal blindness.

Filamentous fungal infections of the cornea: a global overview of epidemiology and drug sensitivity

Fungal keratitis is a serious suppurative, usually ulcerative corneal infection which may result in blindness or reduced vision. Epidemiological studies indicate that the occurrence of fungal keratitis is higher in warm, humid regions with agricultural economy. The most frequent filamentous fungal genera among the causal agents are Fusarium, Aspergillus and Curvularia. A more successful therapy of fungal keratitis relies on precise identification of the pathogen to the species level using molecular tools. As the sequence analysis of the internal transcribed spacer (ITS) region of the ribosomal RNA gene cluster (rDNA) is not discriminative enough to reveal a species-level diagnosis for several filamentous fungal species highly relevant in keratitis infections, analysis of other loci is also required for an exact diagnosis. Molecular identifications may also reveal the involvement of fungal species which were not previously reported from corneal infections. The routinely applied chemotherapy of fungal keratitis is based on the topical and systemic administration of polyenes and azole compounds. Antifungal susceptibility testing of the causal agents is of special importance due to the emergence and spread of resistance. Testing the applicability of further available antifungals and screening for new, potential compounds for the therapy of fungal keratitis are of highlighted interest.

Experimental study on cryotherapy for fungal corneal ulcer

Background

Fungal corneal ulcer is one of the major causes of visual impairment worldwide. Treatment of fungal corneal ulcer mainly depends on anti-fungal agents. In the current study, we developed an integrated combination therapy of cryotherapy and anti-fungal agents to facilitate effective treatment of fungal corneal ulcer.

Methods

Rabbit models of cornea infection were established using a combined method of intrastromal injection and keratoplasty. After treatment with cryotherapy and anti-fungal agents, scanning electron microscopy, transmission electron microscopy, and confocal microscopy were conducted to observe changes in microstructure in the rabbits. Periodic acid Schiff A and hematoxylin and eosin staining were used for detection of histological changes.

Results

Continuous scanning electron microscopy and transmission electron microscopy observations showed that cryothermal treatment inhibited growth of fungal mycelium by destroying fungal cellular structures. Typical cryotherapy was effective in curing fungal corneal ulcer. Different fungi showed different susceptibilities to treatment. The curative effect of Candida albicans was the best, while that of Aspergillus fumigates was the worst.

Conclusions

Our study provides a novel method of a combination of cryotherapy and anti-fungal agents for treatment of fungal corneal ulcer. This treatment could help facilitate the practice of fungal keratitis treatment in the future.

Electronic supplementary material

The online version of this article (doi:10.1186/s12886-015-0011-5) contains supplementary material, which is available to authorized users.

In vitro susceptibility of filamentous fungi from mycotic keratitis to azole drugs

OBJECTIVE

The in vitro antifungal activities of azole drugs viz., itraconazole, voriconazole, ketoconazole, econazole and clotrimazole were investigated in order to evaluate their efficacy against filamentous fungi isolated from mycotic keratitis.

METHODS

The specimen collection was carried out from fungal keratitis patients attending Aravind eye hospital and Post-graduate institute of ophthalmology, Coimbatore, India and was subsequently processed for the isolation of fungi. The dilutions of antifungal drugs were prepared in RPMI 1640 medium. Minimum inhibitory concentrations (MICs) were determined and MIC50 and MIC90 were calculated for each drug tested.

RESULTS

A total of 60 fungal isolates were identified as Fusarium spp. (n=30), non-sporulating moulds (n=9), Aspergillus flavus (n=6), Bipolaris spp. (n=6), Exserohilum spp. (n=4), Curvularia spp. (n=3), Alternaria spp. (n=1) and Exophiala spp. (n=1). The MICs of ketoconazole, clotrimazole, voriconazole, econazole and itraconazole for all the fungal isolates ranged between 16 μg/mL and 0.03 μg/mL, 4 μg/mL and 0.015 μg/mL, 8 μg/mL and 0.015 μg/mL, 8 μg/mL and 0.015 μg/mL and 32 μg/mL and 0.06 μg/mL respectively. From the MIC50 and MIC90 values, it could be deciphered that in the present study, clotrimazole was more active against the test isolates at lower concentrations (0.12-5 μg/mL) when compared to other drugs tested.

CONCLUSION

The results suggest that amongst the tested azole drugs, clotrimazole followed by voriconazole and econazole had lower MICs against moulds isolated from mycotic keratitis.

Incidence and clinical characteristics of fungal keratitis in a Danish population from 2000 to 2013

PURPOSE

Fungal keratitis is a severe sight-threatening condition. The aim of this study was to investigate the incidence and clinical characteristics of fungal keratitis patients living in a temperate climate.

METHODS

By reviewing medical records from 2000 to July 2013, patients with fungal keratitis were identified. Risk factors, clinical signs and outcome were registered.

RESULTS

Twenty-five patients were identified: 52% with Candida, 20% with Fusarium, 16% with Aspergillus and 12% with mixed filamentous fungi. A minimum incidence of fungal keratitis of 0.6 cases per million per year was estimated. Prior topical steroid treatment was commonly found in our cases (44%). Trauma including contact lens wear was associated with infection with filamentous fungi, whereas in patients with Candida infection, ocular surface disease was a prominent feature. Median time from onset of symptoms to diagnosis was 24 days. Only a few patients exhibited classical clinical features such as endothelial plaques (28%), satellite lesions (24%) and feathery edges (16%). The final visual outcome was poor with an average best-corrected logMAR of (mean, 95% CI) 0.70 (0.4-1.0). A total of 52% were treated with corneal transplantation. Patients with Candida infections had a significantly worse visual outcome.

CONCLUSION

We found that patients with fungal keratitis had a poor visual outcome. However, knowledge of risk factors and clinical signs leading to early treatment can improve the prognosis.

Amphotericin-B entrapped lecithin/chitosan nanoparticles for prolonged ocular application

Fungal keratitis is the major cause of vision loss worldwide. Amphotericin-B is considered as the drug of choice for fungal infections. However, its use in ophthalmic drug delivery is limited by the low precorneal residence at ocular surface as a result of blinking reflex, tear turnover and nasopharyngeal drainage. We report Amphotericin-B loaded lecithin/chitosan nanoparticles for prolonged ocular application. The prepared nanoparticles were in the size range of 161.9-230.5 nm, entrapment efficiency of 70-75%, theoretical drug loading of 5.71% with positive zeta potential of 26.6-38.3 mV. As demonstrated by antifungal susceptibility against Candida albicans and Aspergillus fumigatus, nanoparticles were more effective than marketed formulation. They exhibited pronounced mucoadhesive properties. In-vivo pharmacokinetic studies in New Zealand albino rabbit eyes indicated improved bioavailablity (∼ 2.04 fold) and precorneal residence time (∼ 3.36 fold) by nanoparticles prepared from low molecular weight chitosan as compared with marketed formulation.

Role of activated macrophages in experimental Fusarium solani keratitis

Macrophages under the conjunctival tissue are the first line defender cells of the corneas. Elimination of these cells would lead to aggravation of fungal keratitis. To determine how the course of fungal keratitis would be altered after the activation of these macrophages, a murine model was achieved by intrastromal instillation of latex beads before the corneas were infected with Fusarium solani. The keratitis was observed and clinically scored daily. Infected corneas were homogenized for colony counts. The levels of the IL-12, IL-4, MPO, MIF and iNOS cytokines were measured in the corneas using real-time polymerase chain reactions and enzyme-linked immunosorbent assays. CD3+, CD4+ and CD8+ lymphocytes in the corneas, submaxillary lymph nodes and peripheral blood were detected using immunohistochemistry and flow cytometry, respectively. The latex bead-treated mice exhibited aggravated keratitis. Substantially increased macrophage and polymorphonuclear leukocyte infiltration was detected in the corneas, although few colonies were observed. There was a marked increase in the IL-12, IL-4, MPO, MIF and iNOS expression in the corneas. The numbers of CD3+, CD4+ and CD8+ lymphocytes and the CD4+/CD8+ ratio were significantly enhanced in the corneas and submaxillary lymph nodes. However, the number of CD4+ lymphocytes was decreased in the peripheral blood, while the number of CD8+ lymphocytes increased. Collectively, our data demonstrate that the activation of macrophages in the cornea may cause an excessive immune response. Macrophages appear to play a critical role in regulating the immune response to corneal infections with F. solani.

Blindness and Visual Impairment among Adults in a Tertiary Eye Clinic, in Osogbo S W Nigeria

Background:

To plan and implement appropriate management of patients with blindness and visual impairment (VI) requires the knowledge of the common presenting causes.

Aim:

The aim of the following study is to determine the common causes of VI in adults and develop a template for eye care delivery.

Materials and Methods:

A retrospective descriptive analysis of subjects aged 17 years and above who attended LAUTECH Teaching Hospital eye clinic between October 2012 and March 2013. Information on demographic data, visual acuity, anterior and posterior segment examinations, and refraction were obtained from patients’ records. Statistical Package for the Social Sciences version 16. 2, USA was used for descriptive analysis. Chi-square, P values and confidence intervals (CI) were derived for statistical significance.

Results:

A total of 617 cases were reviewed including 306/617 (49.6%) males and 311/617 (50.4%) females. The frequently occurring age-groups were the 51-60 year 120/617 (19.4%) and the 61-70 year 115/617 (18.6%). The common causes of blindness and VI were cataract 225/617 (36.5%, CI: 32.7-40.3), glaucoma 124/617 (20.1%, CI: 16.93-23.25), refractive errors 119/617 (19.3%, CI: 16.17-22.4); trauma and cornea opacities 14/617 (6.1%) each. Refractive error 6/176 (3.4%) was a significant cause of blindness in this study. χ² = 33.68, P < 0.001. More females presented with refractive errors 79/311 (66.4%), while more males presented with trauma 32/306 (78.0%). χ² = 186.47, P < 0.001.

Conclusions:

The common causes of VI are avoidable. Planning for best practice methods, purchase of equipment/instruments, consumables, drugs, and manpower development is required. Establishment of low-cost cataract surgical and refractive services could reduce their incidence.

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

OBJECTIVE

To assess the trends in microbiological organisms identified from corneal scrapings from patients with infectious keratitis at a tertiary care medical centre in South India.

METHODS

We reviewed the records of the microbiology laboratory at Aravind Eye Hospital in Madurai, India, from 2002 until 2012. We identified the microbiological causes of all corneal ulcers from the culture and smear results, and assessed for trends in bacterial and fungal keratitis over time.

RESULTS

Of 23 897 corneal patients with ulcer with a corneal smear from 2002 to 2012 a fungal organism was identified in 34.3%, a bacterial organism in 24.7% and no organism in 38.3%. During this period, the annual number of keratitis cases due to bacteria decreased from 677 to 412, and the annual number due to fungus increased from 609 to 863. In analyses accounting for the total number of outpatients seen each year, the decline in number of smears positive for bacteria was statistically significant (p<0.001) but the increase in the number positive for fungus was not (p=0.73). The relative frequency of individual bacterial or fungal organisms remained relatively stable over this time.

CONCLUSIONS

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.

Fusarium keratitis at a tertiary eye care centre in India

The aim of the study was to report the clinical and microbiological profiles of Fusarium keratitis. In this single-centre, retrospective, non-comparative case series, 47 laboratory-confirmed cases of keratitis caused by Fusarium species treated at the L V Prasad Eye Institute, Bhubaneswar, India, between November 2006 and October 2009, were reviewed. The analysis included predisposing factors, clinical characteristics, microbiological findings, treatment and outcome. Forty-seven samples of 47 patients were included in the study. The mean age of the 47 patients was 46 ± 17 years. Twelve eyes had a history of injury. Corneal scraping could not be done in one of the cases due to large perforation. Fungal filaments were detected in corneal scraping in 41 cases, and in three cases microconidia were observed in microscopy. Fusarium solani was the most common species (44.7 %). All three cases where microconidia were present in smear were identified as F. solani in culture. The mean time to positive culture was 2.4 ± 1.5 days. Twenty-three patients underwent adjunctive surgical procedure. Visual acuity of <20/200 at presentation and final follow-up was noted in 80.9 and 51.4 % patients, respectively. One-half (23/47) of the patients had improvement in visual acuity. Fusarium keratitis may present after trauma without any satellite lesion, and the response to medical therapy is generally poor. Rapid diagnosis can be made by smear examination of corneal scrapings in a majority of the cases and confirmed by culture within 2-3 days. Presence of microconidia in smear examination may be suggestive of F. solani.

Safety and efficacy of intrastromal injection of 5% natamycin in experimental fusarium keratitis

PURPOSE

To compare the efficacy of combined intrastromal injection and topical natamycin 5% to standard topical therapy alone in an experimental rabbit model of Fusarium keratitis.

METHODS

Fungal keratitis was induced in the right eyes of 12 New Zealand rabbits by stromal injection of Fusarium solani spore suspension into the cornea. Four days after inoculation, animals were randomly assigned to 2 different treatment groups (n=6 in each group). The study group received intrastromal injections of natamycin 5% on treatment day 1 and 4, combined with topical natamycin 5% eye drops given hourly between 8:00 and 20:00 for the first 2 days, followed by 4 times daily on days 3-11. The control group received only topical natamycin 5% at identical intervals. Eyes were examined clinically on days 1, 4, 7, and 11 for status of corneal healing, corneal vascularization, and hypopyon. Animals were sacrificed on day 11, and corneas were subjected to histopathological examination.

RESULTS

Both groups showed significant improvement in terms of conjunctival hyperemia, size and density of corneal infiltrate, corneal edema, and total clinical score. In the study group, there was a significant improvement in the height of hypopyon in the anterior chamber, while there was also an increased amount of vascularization.

CONCLUSIONS

This study showed that intrastromal injection of natamycin 5% combined with topical treatment has little beneficial effect over topical therapy in a Fusarium keratitis rabbit model. The addition of intrastromal injection should be reserved to the most severe or recalcitrant cases.

Clinical utility of caspofungin eye drops in fungal keratitis

Treatment of fungal keratitis remains challenging. To date, only the polyenes and azoles are commonly used topically in the management of fungal keratitis. Natamycin, a polyene, is the only antifungal eye drop that is commercially available; the remainder are prepared in-house and are used in an 'off-label' manner. Failure of medical treatment for fungal keratitis is common, hence there is a need for more effective topical antifungal therapy. To increase the antifungal eye drop armamentarium, it is important to investigate the utility of other classes of antifungal agents for topical use. Caspofungin, an echinocandin antifungal agent, could potentially be used to address the existing shortcomings. However, little is known about the usefulness of topically administered caspofungin. This review will briefly explore the incidence, epidemiology and antifungal treatment of fungal keratitis. It will focus primarily on evidence related to the efficacy, safety and practicality of using caspofungin eye drops in fungal keratitis.

[A case of mycotic keratitis due to Fusarium solani in Valdivia, Chile]

BACKGROUND

Keratomycosis is one of the most prevalent ophthalmic infections, which needs a specific treatment depending on the nature of the infecting fungus. The prognosis is usually severe and depends on an early diagnosis and suitable therapy.

CASE REPORT

We describe a case of keratitis due to Fusarium solani in a patient from a rural area, who, between May and October 2011, suffered a corneal trauma caused by dust particles in Valdivia, Chile. On two occasions, direct examination of eye scrapes revealed abundant septate hyphae. All cultures were positive for the same fungus, which was identified as Fusarium solani by phenotypic characterization and sequencing of ribosomal nuclear genes. The patient was initially treated with amphotericin B and afterwards successfully responded to a treatment with oral and intravenous voriconazole, although corneal opacity persisted.

CONCLUSIONS

Although keratomycosis in Chile is rare, its diagnostic particularities must be taken into consideration to establish the most effective treatment. Thus, a rapid visualization of the fungus in the lesion, an efficient isolation of the etiologic agent in pure culture is essential, as well as its rapid identification, which requires the use of molecular sequencing techniques in the case of Fusarium species.

Aspergillus and Fusarium corneal infections are regulated by Th17 cells and IL-17-producing neutrophils

Fusarium and Aspergillus species of mold are major causes of corneal infections in the United States and worldwide, resulting in severe visual impairment and blindness. As there is evidence for T cell responses to these pathogenic fungi in infected individuals, we examined the role of IL-17A (IL-17) and IFN-γ in murine models of fungal keratitis. We found that C57BL/6 mice given intratracheal or s.c. immunization of conidia prior to corneal infection exhibited enhanced fungal killing and lower corneal opacity compared with unimmunized mice. Protective immunity was associated with temporal recruitment of IL-17-producing neutrophils and Th17 and Th1 cells and dependent on production of IL-17 but not IFN-γ. Protection was also impaired in neutrophil-depleted and Rag2(-/-) mice. Together, the results of these studies identify an essential role for IL-17-producing neutrophils and Th17 cells in regulating the growth of fungal hyphae and the severity of corneal disease.

The spectrum and aetiology of mycotic infections from a tertiary care hospital from Western part of India

BACKGROUND

In the past few years, there has been an increase in infections caused by fungal aetiology. This is mainly due to increase in sizes of populations which are at risk. Also, fungi which were previously considered as non-pathogenic have been increasingly implicated. Hence, this study was taken up.

AIM

To assess the magnitude of mycotic infections in this set up. To assess the spectrum of fungi which are involved in various infections.

MATERIAL AND METHODS

Total 704 samples taken over two and half period were included. They consisted of various samples like sputum, blood, urine, sterile body fluids, corneal scrapings. These were processed by conventional mycological techniques. These included direct microscopy after Gram staining and KOH mount, culture on Sabouraud's dextrose agar (SDA), corn meal agar, brain heart infusion (BHI), brain heart infusion agar (BHIA) and others, as required. For non-albicans Candida, the automated Vitek 2 C system was used. Various moulds and yeasts were identified up to genus level and species level.

RESULTS

Of 704 samples, 336 (48%) were positive for fungal culture. Of these, 244 isolates were yeast like fungi, 81 were moulds, 7 were yeasts and 4 were dimorphic. Among blood stream infections, non-albicans Candida were the commonest isolates. In the urine samples, C. albicans was the commonest isolate. From corneal scrapings, only moulds and dimorphic fungi were isolated.

CONCLUSION

Incidence of non- albicans Candidal infections is increasing. Culture and identification of mycotic infections is essential for commencement of suitable antifungal therapy.

[Clinical and microbiological features of severe infectious keratitis during heatwaves]

PURPOSE

To study clinical and microbiological features of patients with severe microbial keratitis during a heatwave. To evaluate the links between disease severity, causative micro-organisms and temperature variation.

METHODS

Retrospective study of patients with microbial keratitis hospitalized in a referral center during the summer months (between June 1, 2009 and September 30, 2009), separated into two groups by date of hospitalization (heatwave vs non-heatwave). Prevalence and daytime temperatures were compared for data collected during the summers of 2009 (heatwave), 2008 (temperate) and 2003 (prolonged heatwave).

RESULTS

Thirty-three patients were hospitalized during the summer of 2009, with an average age of 51 years and an average stay of 15 days. The primary predisposing factor was the use of contact lenses (36%), followed by pre-existing corneal disease (15%) and systemic disease (15%). Prevalence of severe keratitis was higher in periods of heatwaves vs periods of no heatwaves (mean 9.8 patients vs 3.1, P<0.001). Best corrected visual acuity progressed from 1/30 at admission to 1/10 at 1 month after discharge (P<0.001). The most common bacteria identified were Gram-positive cocci (CNS 27%) and Pseudomonas (23%). Microbiological results were similar in the two groups. Similar variations between the prevalence of severe keratitis and daytime temperatures were found for the summer of 2009 as well as for the summers of 2008 and 2003.

CONCLUSIONS

There appears to be a link between climatic temperature variations and the prevalence of severe microbial keratitis.

Fonsecaea pedrosoi: a rare etiology in fungal keratitis

Fungal corneal ulcer is common in India due to tropical climate and a large agrarian population that is at risk. Fonsecaea pedrosoi is the most common agent of chromoblastomycosis, a chronic localized fungal infection of the skin and subcutaneous tissues mainly involving lower extremities. We report a rare case of corneal chromoblastomycosis caused by F.pedrosoi, which was successfully treated with topical Amphotericin B followed by a long course of oral antifungal therapy. To the best of our knowledge, this is the first case of mycotic keratitis caused by F.pedrosoi, from the foothills of Himalayas.