Incidence Of Fungal Keratitis Research Articles

FUNGAL KERATITIS - AN UPDATE ON THE GLOBAL THREAT

Fungal keratitis (FK) is a sight-threatening disease caused by infection of the cornea by filamentous fungi or yeasts. FK can be challenging to diagnose and treat. In tropical, low, and middle-income countries, it accounts for the majority of cases of microbial keratitis (MK). Filamentous fungi, in particular, Fusarium spp., the aspergilli, and dematiaceous fungi are responsible for the most significant burden of disease. The predominant risk factor for filamentous fungal keratitis is trauma, typically with organic, plant-based material. In 2020, the incidence of FK was estimated to be over 1 million cases per year, with a significant geographical variation. Diagnosing FK is challenging accurate diagnosis relies on reliable microscopy and culture. Current topical antifungals are not very effective infections can progress despite prompt treatment. Antifungal drops are often unavailable. When available, natamycin is usually the first-line treatment. However, infections may progress to perforation in ~25% of cases. Future work needs to be directed at addressing these challenges and unmet needs. This review discusses the epidemiology, clinical features, diagnosis, management, and etiology of FK.

Correlation between clinical and laboratory culture findings in resistant keratitis

Background: The clinical diagnosis of infective keratitis does not give an unequivocal indication of the causative organisms because a wide range of organisms can produce a similar clinical picture. The causative agents of infective keratitis frequently isolated are: bacteria, fungi, viruses and Parasites. Aim and Objectives: The purpose of this study was to identify the correlation between clinical and culture laboratory finding in resistant keratitis at the Ophthalmology Department of Tanta University Hospitals. Subjects and Methods: This study was a prospective interventional selectively randomized clinical study which extended for 12 months at Tanta university hospitals and included fifty eyes of fifty patients clinically diagnosed resistant keratitis and presenting to The Ophthalmology Department of Tanta University Hospitals. The study started in January 2021. Results: there was statistically significant deference between groups regarding to Medical history, Trauma, Ulcer characteristics, Satellite lesions and corneal sensation. There was no statistically significant deference between groups regarding to age, gender, Contact wearing, foreign body, Ulcer size and gutter and immune ring. Conclusion: Clinical diagnosis is more important for treatment and follows up while culture is performed for documentation of the clinical findings. Incidence of fungal keratitis is significantly high in our region. The therapeutic approach can initially be based on clinical impression and evidence of the microbiologic trends of infectious keratitis and sensitivity/resistance patterns in our locality.

Incidence of fungal keratitis in Libya: An epidemiological study

Incidence of fungal keratitis in Libya: An epidemiological study

Incidence of fungal keratitis in Libya: An epidemiological study

Objectives: The aim of this study was to assess the occurrence of eye fungal infection among patients attending the eye hospital in Tripoli city, Libya. Materials and Methods: Seventy-one patients with ocular fungal infections were subjected to clinical and microbiological investigations. They were selected from patients attending the Tripoli Eye Hospital. The specimens of the external ocular infections were collected using sterile swab and inoculated to different culture media. Data were presented as count and percentages. Results: The current findings showed that Aspergillus was the most common causative agent, being responsible for 91.54% of the all cases, followed by Candida albicans (8.46%). Conclusion: Occurrence of fungal keratitis gradually increased in the years after 2009, especially after 2013. Knowledge of the pathological course and clinical features of fungal keratitis will undoubtedly bead in early diagnosis and treatment, with reduction in ocular morbidity.

Serious fungal disease incidence and prevalence in Indonesia.

Indonesia is a tropical country, warm and humid, with numerous environmental fungi. Data on fungal disease burden help policymakers and clinicians. We have estimated the incidence and prevalence of serious fungal diseases. We found all published and unpublished data and estimated the incidence and prevalence of fungal diseases based on populations at risk. HIV data were derived from UNAIDS (2017), pulmonary tuberculosis (PTB) data from 2013-2019, data on chronic pulmonary aspergillosis (CPA) were used to estimate CPA prevalence and likely deaths, COPD data from Hammond (2020), lung cancer incidence was from Globocan 2018, and fungal rhinosinusitis was estimated using community data from India. Overall ~7.7 million Indonesians (2.89%) have a serious fungal infection each year. The annual incidence of cryptococcosis in AIDS was 7,540. Pneumocystis pneumonia incidence was estimated at 15,400 in HIV and an equal number in non-HIV patients. An estimated 1% and 0.2% of new AIDS patients have disseminated histoplasmosis or Talaromyces marneffei infection. The incidence of candidaemia is 26,710. The annual incidence of invasive aspergillosis was estimated at 49,500 and the prevalence of CPA is at 378,700 cases. Allergic bronchopulmonary aspergillosis prevalence in adults is estimated at 336,200, severe asthma with fungal sensitisation at 443,800, and fungal rhinosinusitis at 294,000. Recurrent vulvovaginal candidiasis is estimated at 5 million/year (15-50years old). The incidence of fungal keratitis around 40,050. Tinea capitis prevalence in schoolchildren about 729,000. Indonesia has a high burden of fungal infections.

Etiological factors & microbiological characteristics of infectious keratitis in western Maharashtra

To identify the etiological factors and study the microbiological characteristics of infectious keratitis in Western Maharashtra. This was a prospective observational hospital‐based study conducted at the Department of Ophthalmology, at a tertiary care hospital, in a part of central India. Data related to socioeconomic status and etiological factors was collected. Results were analyzed on the basis of history, slit lamp examination, microbiological scraping and culture results. During the period of September 2018 to August 2020, a total of 60 patients with infectious keratitis were examined in the Ophthalmology OPD. Majority of patients of infectious keratitis were between 61 and 70 (18.33%) age group. Incidence in male was higher (68%) than female. Ocular trauma was the most common etiological factor (52%). Prevalence of Fungal keratitis (52%) was higher than bacterial (46%) in this part of India. 57% subjects showed organism on Gram staining. 53% subjects showed KOH positivity. 68.3% showed growth over microbiological culture with the most common species isolated as Fusarium species (26.6%) followed by Pseudomonas aeruginosa. Incidence of fungal keratitis is higher in this part of Western Maharashtra. Most common etiological factor was determined to be trauma with vegetative matter among farmers which tells us that they are most prone for infectious keratitis. Prompt diagnosis, microbiological scraping, culture growth identification and starting on appropriate treatment can help reduce the morbidity of corneal ulcers.

Fungal Keratitis in Northern Thailand: Spectrum of Agents, Risk Factors and Putative Virulence Factors

Fungal keratitis (FK) is a serious ocular infection that can result in various degrees of vision loss, including blindness. The aim of the study was to identify and retrospectively review all FK cases diagnosed between August 2012 and December 2020 at a tertiary care hospital in northern Thailand with a specific focus on epidemiologic features, including season, patient sex and age, the spectrum of pathogens, and presence of certain putative virulence factors. Of 1237 patients with corneal ulcers, 294 (23.8%) were confirmed by direct microscopic examination and/or fungal culture. For the positive cases, direct examinations of Calcofluor white (CW) stains and KOH mounts were found in 97.3% (286/294) and 76.5% (225/294), respectively (p < 0.05). Of the cases diagnosed by microscopy and culture, fungi were isolated in 152 (51.7%), with Fusarium spp. being the most frequently identified (n = 69, 45.5%) followed by dematiaceous fungi (n = 45, 29.6%) and Aspergillus spp. (n = 18, 11.8%). The incidence of FK was higher in the rainy season of July to October. The mean age was 54.4 ± 14.4 (SD) years, with a range of 9–88 years. Males (75.8%) were affected significantly more than females (24.2%) (p < 0.05). Of 294 patients, 132 (44.9%) were middle-aged adults (41–60 years) and 107 (36.4%) were older than 60 years. Trauma to the eye by soil or vegetative matter were the most common preceding factors (188/294; 64.0%). We assessed two virulence factors. First, 142 of the 152 culture-positive FK cases were due to molds, indicating that hyphal morphogenesis is extremely important in disease. We also demonstrated that fungal melanization occurs in the molds during the course of FK by applying a melanin-specific monoclonal antibody (MAb) that labeled fungal elements in corneal samples of patients, and melanin particles derived from the hyphae were also recovered after treatment of the samples with proteolytic enzymes, denaturant and hot concentrated acid. In summary, we demonstrate that northern Thailand has a high rate of FK that is influenced by season and males engaged in outside activities are at highest risk for disease. Moulds are significantly more commonly responsible for FK, in part due to their capacity to form hyphae and melanins. Future studies will examine models of fungal corneal interactions and assess additional factors of virulence, such as secreted enzymes, to more deeply decipher the pathogenesis of FK.

Mycotic Keratitis-A Global Threat from the Filamentous Fungi.

Mycotic or fungal keratitis (FK) is a sight-threatening disease, caused by infection of the cornea by filamentous fungi or yeasts. In tropical, low and middle-income countries, it accounts for the majority of cases of microbial keratitis (MK). Filamentous fungi, in particular Fusarium spp., the aspergilli and dematiaceous fungi, are responsible for the greatest burden of disease. The predominant risk factor for filamentous fungal keratitis is trauma, typically with organic, plant-based material. In developed countries, contact lens wear and related products are frequently implicated as risk factors, and have been linked to global outbreaks of Fusarium keratitis in the recent past. In 2020, the incidence of FK was estimated to be over 1 million cases per year, and there is significant geographical variation; accounting for less than 1% of cases of MK in some European countries to over 80% in parts of south and south-east Asia. The proportion of MK cases is inversely correlated to distance from the equator and there is emerging evidence that the incidence of FK may be increasing. Diagnosing FK is challenging; accurate diagnosis relies on reliable microscopy and culture, aided by adjunctive tools such as in vivo confocal microscopy or PCR. Unfortunately, these facilities are infrequently available in areas most in need. Current topical antifungals are not very effective; infections can progress despite prompt treatment. Antifungal drops are often unavailable. When available, natamycin is usually first-line treatment. However, infections may progress to perforation in ~25% of cases. Future work needs to be directed at addressing these challenges and unmet needs. This review discusses the epidemiology, clinical features, diagnosis, management and aetiology of FK.

Epidemiology of Aspergillus species causing keratitis in Mexico.

The incidence of fungal keratitis has increased in recent years. While the epidemiology and clinical roles of various Candida and Fusarium species have been relatively well-identified in infections of the eye, data regarding keratitis caused by Aspergillus species are scant. Accurate and rapid diagnosis is important for successful management of this infection. To present the first molecular epidemiological data from Mexico during a 4-year period of cases admitted with Aspergillus keratitis to a tertiary care eye institution in Mexico City. A total of 25 cases of keratitis were included in the study. Aspergillus isolates were identified by sequencing the calmodulin gene. Antifungal susceptibility was tested according to CLSI. The aetiological agents belonged to Aspergillus flavus (n=13), Aspergillus effusus (n=1), Aspergillus tamarii (n=4), Aspergillus sydowii (n=1), Aspergillus protuberus (n=3) and Aspergillus terreus (n=3). All strains had low minimum inhibitory concentrations (MICs) of itraconazole and voriconazole (VCZ). Amphotericin B and natamycin showed moderate elevated MICs. Early diagnosis and application of topical VCZ 1% were associated with good outcome. Monitoring of local epidemiological data plays an important role in clinical practice.

Epidemiological, clinical and laboratory findings of infectious keratitis at Mansoura Ophthalmic Center, Egypt.

To analyze the epidemiological, clinical and laboratory findings of infectious keratitis. A retrospective study on cases of infective keratitis, attended our institution from Mar. 2013 to Feb. 2015, was done at Mansoura Ophthalmic Center, Egypt. Corneal scrapings were performed and processed for direct microscopy and culture in appropriate media using standard laboratory protocols. Out of 245 patients enrolled for study, 247 corneal scrapings were obtained. Ocular trauma was the most common predisposing factor (51.4%), followed by diabetes mellitus (15.1%). Cultures were positive in 110 scraping samples (44.5%): 45.5% samples had pure fungal infection, 40% had pure bacterial infections and 10% had mixed fungal and bacterial growths. Acanthamoeba was detected in 5 (4.5%) samples. The most common fungal pathogen was Aspergillus spp. (41%). The most common bacterial isolates were Staphylococcus aureus (38.2%) and Pseudomonas aeruginosa (21.8%). Incidence of fungal keratitis is high in our region. Therapeutic approach can initially be based on clinical features and sensitivity/resistance patterns. Microbiological research should direct the antimicrobial treatment. Antibiotic resistance to fluoroquinolones and aminoglycosides is an important consideration.

Fungal Keratitis in North India: Spectrum of Agents, Risk Factors and Treatment.

To assess the prevalence of fungal keratitis, we conducted a retrospective study over 7years (2005 through 2011) at a tertiary care center in North India. Effort has been made to analyze the disease burden, spectrum of agents and treatment history. The findings were compared with an earlier study at the same center for any change in the epidemiology of the disease. Microbiology records were screened at the Postgraduate Institute of Medical Education and Research, Chandigarh, India, to identify fungal keratitis cases, and available clinical records of those cases were analyzed. Of 2459 clinically suspected fungal keratitis cases, 765 (31%) cases were direct microscopy confirmed. Of these microscopy-confirmed cases, fungi were isolated in 393 (51.4%), with Aspergillus spp. ranked top (n=187, 47.6%), followed by melanized fungi (n=86, 21.9%) and Fusarium spp. (n=64, 16%). A male predominance of 78.7% was noted with a peak in the incidence of fungal keratitis during post-monsoon season (September to November). A delay in diagnosis was significantly associated (p<0.001) with keratitis cases due to melanized fungi. In comparison with an earlier study, higher isolation of melanized fungi was noted with a widening of the spectrum of agents identified. Thus, fungal keratitis due to Aspergillus spp. remains a serious ocular illness among the active male population in North India with relative rise of keratitis due to melanized fungi. The spectrum of agents causing fungal keratitis has broadened with many rare fungi that are implicated.

Is fungal disease in Sri Lanka underestimated? A comparison of reported fungal infections with estimated disease burden using global data

Introduction With an increase in the elderly population and developments in medical care, increased numbers of patients with fungal diseases are expected. This necessitates a new vision for fungal diseases in Sri Lanka, a tropical country with a population of 20 million. The objective of this study was to estimate national fungal infection caseloads using global and national epidemiological datasets. Methods We searched national data and surveillance studies published by us and other authors for relevant disease terms. Locally collected incidence data were available for candidaemia, fungal keratitis, cryptococcosis, allergic broncho-pulmonary aspergillosis (ABPA) and severe asthma with fungal sensitization (SAFS). Global disease estimation was done using international data. Generally, disease estimates were conservative as they assumed the lowest incidence rates reported in the literature and focused only on well-defined risk populations. Results Among the 1,317 HIV/AIDS patients (in 2010), there were 639 estimated oral candidiasis cases, 100 oesophageal candidiasis cases and only 13 cases of cryptococcal meningitis. The estimated prevalence of chronic pulmonary aspergillosis (CPA) post TB is estimated to be 1,443 and all forms of chronic pulmonary aspergillosis (including aspergilloma) 2,886 patients. We estimated 229 cases of invasive aspergillosis and 41 cases of mucormycosis. The projected annual incidence of candidaemia is 507 and an estimated 76 candida peritonitis cases post-surgery. According to our estimates 10,344 patients were suffering from ABPA and 13,654 were suffering from SAFS. The projected annual incidence of fungal keratitis would be 1,277 and tinea infections would affect 50 children. Pneumocystis incidence could not be estimated. Conclusions Our estimates suggest that candidaemia and invasive aspergillosis could be the leading causes of fungal-associated deaths in Sri Lanka whereas globally it is due to SAFS, ABPA and CPA. More precise data from the whole country is needed to validate these estimates. Such data would be very useful for developing healthcare policies for prevention, diagnosis and treatment of serious fungal infections.

English

The incidence of fungal keratitis has shown a dramatic increase in the recent years. This was a patient who following fall of insect presented with pain, redness and watering in right eye. Examination revealed an 4x5mm oval ulcer with slough. Laboratory evaluation showed Helminthosporium sp., Though Helminthosporium sp., of fungus rarely cause disease in humans it should be kept in mind in immunocompromised individuals and patients using the over the counter drugs.

Epidemiological Characteristics and Laboratory Diagnosis of Fungal Keratitis in Patients with Corneal Ulcer in Riyadh, Saudi Arabia

Corneal blindness is a major health problem worldwide and infectious keratitis is one of the predominant causes. The incidence of fungal keratitis has increased over the last few years. Keeping this in mind, this study was conducted to evaluate the frequency of positive fungal cultures in infectious keratitis and of the various fungal species identified as etiologic agents in patients with corneal ulcer attending the ophthalmic departments of 3 hospitals in Riyadh. Corneal scrapings from 100 patients of corneal ulcer with suspected fungal etiology were subjected to direct examination by 10% KOH and lacto-phenol cotton blue mount. Also swabs of diseased eyes were taken with sterilized swabs. The specimens were also inoculated directly on to Sabouraud’s dextrose agar in C-shaped streaks. From 100 patients of corneal ulcer investigated, only 52% of patients were positive. Males were more commonly affected than females (69.23% and 30.76%), respectively. The age of patients was ranged from 28-55 years. 18 (34.61%) patients with fungal keratitis were laborers, 15 (28.84%) teachers, 7 (13.46%) housewives, 6 (11.53%) shepherds and 6 (11.53%) were civil engineers. Corneal trauma with stone chips and metal splinters appeared to be the most common predisposing factors of fungal keratitis (30.76%) followed by ocular surgery and corneal disease (26.92%). Of 52 positive patients with corneal ulcer surveyed the most important causative agents of fungal keratitis were Aspergillus spp. (44.23%), followed by Candida spp. (17.30%) and Fusarium spp. (17.30%). Because of serious consequences of infectious keratitis, it is important to know the exact etiology of fungal keratitis to institute appropriate therapy in time. Laboratory confirmation should be before pre scribing corticosteroids and antifungal.

The incidence of fungal keratitis in Zagazig University Hospitals, Egypt and the value of direct microscopy and PCR technique in rapid diagnosis

Amac: Fungal keratit (FK) sikliginin, risk faktorlerinin ve korneal orneklerin direkt mikroskopi ile incelenmesi ve PCR tekniginin tani degerinin arastirilmasi.Yontemler: Misir’da, Zagazig Universitesi Hastaneleri Goz Hastaliklari Departmani’nda Ocak-Haziran 2012 arasinda keratit tanisi alan hastalar calismaya alindi. Korneal ornekler %10 KOH preparasyon yontemi ile direkt mikroskopi ile incelendi, ayrica ornekler PCR ile fungal DNA varligi acisindan test edildi vekultur plaklarina ekim yapildi. Korneal smear direkt mikroskopi ve PCR bulgulari kultur sonuclari ile testlerin duyarliligi, guvenirligi, uygunlugu ve tahmin degerleri acisindan karsilastirildi.Bulgular: Calisma suresince toplam 350 hasta keratit olarak degerlendirilerek bunlardan 60 tanesi rastgele ornekleme yontemiyle calismaya dâhil edildi. Toplam 60 hastanin 33’unde (% 55,0) kulturde fungus uremesi ile FK tanisi dogrulandi. Goz travmasi en sik predispozan faktor olarak degerlendirildi (% 63,6). En sik fungal ajan Penicillium spp. idi (% 24,2) ve bunu Aspergillus fumigatus (% 21,2) takip etti. Direkt mikroskopinin FK tanisinda duyarliligi % 100, ozgullugu %66,7, pozitif tahmin degeri (PPV) % 78,6 ve negatif tahmin degeri (NPV) % 100 olarak hesaplandi. PCR tekniginin ise duyarliligi % 100, ozgullugu % 88,9, PPV % 91,7 ve NPV % 100 olarak hesaplandi.Sonuclar: FK tanisinda PCR, kultur negatif olgularda onemli oranda fungal etiyolojiyi gosterebilmesine ragmen, pahali olmasi sebebiyle FK tanisinda rutin tanisal test yontemi olarak kullanilamayacagini, bunun yerine daha ekonomik, daha hizli ve duyarli bir yontem olan korneal orneklerin direkt mikroskopik incelemesinin daha uygun oldugunu dusunuyoruz

Aetiology analyses of 334 cases fungal keratitis

To analyze the distribution of pathogenic bacterium of the fungal keratitis patients for providing the data of clinical diagnosis and treatment. From July 2005 to December 2010 in Shandong Eye Hospital there were 352 smears of corneal ulcers and corneal tissue exemplar removed in surgery from fungal keratitis patients. The all exemplars were cultured with the Sabouraud dextrose agar culture media in 28°C under the humidor for 7 days. The strains was identified according to the appearance of fungal colonies, mycelium, spore shape, spore arrangement and fungal shape. And there did the retrospective analyses about the positive rate of fungal culture, genus distribution, seasonal distribution and sources of patients, sex ratio, age distribution and occupation. etc. There were 334 stock positive fungal culture in 352 cultured specimens from fungal corneal ulcers, the positive rate was 94.9%. There were 187 positive culture from 203 corneal scraping exemplars, the positive rate was 92.1%; there were 147 positive culture from 149 corneal tissue removed in surgery, the positive rate was 98.7%. The Fusarium strains was most common in all isolated strain, 211 (63.2%). The Aspergillus was secondly 47 (14.1%). The character of seasonal distribution of culture positive strain: the 48 strains (14.4%) were cultivated from January to March; the 48 strains (14.4%) were cultivated from April to June; the 64 strains were cultivated (19.2%) from July to September; the 174 strains (52.0%) were cultured from October to December, the ratio were 1:1:1.3:3.6 quarterly (χ(2) = 3.360, P = 0.339). The incidence of fungal keratitis were higher in the autumn and winter than in spring and summer. The ratio of the male and the female was 2.04:1 in 334 culture-positive patients; the mean age was (48 ± 22) years old. The 217(65%) came from farmer in the developed group, and the other 117 cases came from other occupations (35%). The 289 (87%) cases came from Shandong Province in 334 positive patients, the 45 cases (13%) came from other province of Province. Chi-square test method was used to analysis the differences of incidence of fungal keratitis among the four seasons using SPSS11.5. The Fusarium is the most important pathogen in fungal keratitis in Shandong Province. The high positive culture rate of fungal keratitis specimens plays an important role in clinical diagnosis and treatment.

A 5-Year Retrospective Review of Fungal Keratitis at Hospital Universiti Sains Malaysia

Background. Corneal blindness from healed infected keratitis is one of the most preventable causes of monocular blindness in developing countries, including Malaysia. Our objectives were to identify the causative fungi, predisposing risk factors, the proportion of correct clinical diagnosis, and visual outcome of patients treated in our hospital. Methods. A retrospective review of medical and microbiology records was conducted for all patients who were treated for fungal keratitis at Hospital Universiti Sains Malaysia from January 2007 until December 2011. Results. Forty-seven patients (47/186, 25.27%) were treated for fungal keratitis during the study period. This demonstrated that the incidence of fungal keratitis has increased each year from 2007 to 2011 by 12.50%, 17.65%, 21.21%, 26.83%, and 28.57%, respectively. The most common predisposing factors were injury to the eye followed by use of topical steroid, and preexisting ocular surface disease. Fusarium species were the most common fungal isolated, followed by Candida species. Clinical diagnosis of fungal keratitis was made in 26 of the 41 (63.41%) cases of positive isolates. Of these, in eleven cases (23.40%) patients required surgical intervention. Clinical outcome of healed scar was achieved in 34 (72.34%) cases. Conclusions. The percentage of positive fungal isolated has steadily increased and the trend of common fungal isolated has changed. The latest review regarding fungal keratitis is important for us to improve patients' outcome in the future.

Detection of Aspergillus keratitis in ocular infections by culture and molecular method

The incidence of fungal keratitis has increased in recent years. Since accurate and rapid diagnosis is important for the proper management of this infection, we evaluated the use of nested PCR to detect Aspergillus-specific DNA in corneal scrapings for the diagnosis of Aspergillus keratitis. From April 2005 to September 2008, patients with eye findings suspicious for fungal keratitis were enrolled for corneal sampling. After ocular examination, we carried out laboratory testing including direct microscopy and culture examination of corneal scrapings, nested PCR and histopathological examination of the corneal tissues obtained at surgery. Of the 57 infected eyes suspicious for fungal keratitis, 32 (56.14%) were reported as Aspergillus keratitis by PCR assay, from which 12 (37.5%) were positive in culture and direct smear for Aspergillus keratitis, and 20 (62.5%) had clinical signs of fungal keratitis (probable). All PCR-positive cases were judged to have fungal infections, based on their responses to the antifungal treatment. The use of molecular methods in high-risk patients can be helpful in diagnosis of fungal infections and can have important public health implications for both the treatment and prevention of suppurative corneal ulcerations. The significance of this study lies in the analysis of the proven cases in terms of both laboratory findings and responses to the treatment.

Microbial Keratitis in South India: Influence of Risk Factors, Climate, and Geographical Variation

Purpose: To determine the influence of risk factors, climate, and geographical variation on the microbial keratitis in South India. Methods: A retrospective analysis of all clinically diagnosed infective keratitis presenting between September 1999 and August 2002 was performed. A standardised form was filled out for each patient, documenting sociodemographic features and information pertaining to risk factors. Corneal scrapes were collected and subjected to culture and microscopy. Results: A total of 3,183 consecutive patients with infective keratitis were evaluated, of which 1,043 (32.77%) were found to be of bacterial aetiology, 1,095 (34.4%) were fungal, 33 (1.04%) were Acanthamoeba, 76 (2.39%) were both fungal and bacterial, and the remaining 936 (29.41%) were found to be culture negative. The predominant bacterial and fungal pathogens isolated were Streptococcus pneumoniae (35.95%) and Fusarium spp. (41.92%), respectively. Most of the patients (66.84%) with fungal keratitis were between 21 and 50 years old, and 60.21% of the patients with bacterial keratitis were older than 50 (p < 0.0001) (95% CI: 5.19–7.19). A majority of patients (64.75%) with fungal keratitis were agricultural workers (p < 0.0001) [odds ratio (OR): 1.4; 95% CI: 1.19–1.61], whereas bacterial keratitis occurred more commonly (57.62%) in nonagricultural workers (p < 0.0001) (OR: 2.88; 95% CI: 2.47–3.36). Corneal injury was identified in 2,256 (70.88%) patients, and it accounted for 92.15% in fungal keratitis (p < 0.0001) (OR: 7.7; 95% CI: 6.12–9.85) and 100% in Acanthamoeba keratitis. Injuries due to vegetative matter (61.28%) were identified as a significant cause for fungal keratitis (p < 0.0001) (OR: 23.6; 95% CI: 19.07–29.3) and due to mud (84.85%) for Acanthamoeba keratitis (p < 0.0001) (OR: 26.01; 95% CI: 3.3–6.7). Coexisting ocular diseases predisposing to bacterial keratitis accounted for 68.17% (p < 0.0001) (OR: 33.99; 95% CI: 27.37–42.21). The incidence of fungal keratitis was higher between June and September, and bacterial keratitis was less during this period. Conclusion: The risk of agricultural predominance and vegetative corneal injury in fungal keratitis and associated ocular diseases in bacterial keratitis increase susceptibility to corneal infection. A hot, windy climate makes fungal keratitis more frequent in tropical zones, whereas bacterial keratitis is independent of seasonal variation and frequent in temperate zones. Microbial pathogens show geographical variation in their prevalence. Thus, the spectrum of microbial keratitis varies with geographical location influenced by the local climate and occupational risk factors.

Spectrum of Fungal Keratitis in North China

To report the epidemiological features, laboratory findings, and treatment outcomes in patients with fungal keratitis in north China. Retrospective hospital-based study. A total of 654 patients diagnosed with fungal keratitis at the Shandong Eye Institute from January 1999 to December 2004. The medical records of 654 inpatients (654 eyes) with fungal keratitis were reviewed retrospectively for demographic features, risk factors, seasonal variation, clinical characteristics, laboratory findings, and treatment strategy. Patient history, ocular examination findings by slit-lamp biomicroscopy, laboratory findings from direct smear examination and fungal culture, and treatment protocol. Fungal keratitis constituted 61.9% of cases of severe infective keratitis among the inpatients at the Shandong Eye Institute during the 6 years. Males (60.6%) were more likely to be affected by fungal keratitis than females (39.4%). Almost one third of the patients (203) were middle aged (41-50 years old). Corneal trauma (51.4%), especially injury from plants (25.7% in all patients), was the most commonly associated risk factor. The incidence of fungal keratitis was higher in harvest seasons, including summer and autumn. An increasing tendency of incidence was noted in more recent years. Direct microscopic examination of the corneal scraping samples stained with potassium hydroxide showed positivity in 88.7% of the eyes. The fungal isolates were of Fusarium species in 437 eyes (73.3%) and Aspergillus species in 72 eyes (12.1%). Surgical interventions were performed in 604 eyes (92.4%), including therapeutic penetrating keratoplasty in 399 eyes (66.0%) and therapeutic lamellar keratoplasty (LK) in 177 eyes (29.3%). Globe integrity was preserved in 626 eyes (95.7%). With Fusarium species being the most commonly isolated pathogens, fungal keratitis is the leading cause of severe infective corneal ulcers in north China. Direct microscopic examination with potassium hydroxide wet mounts proves to be a rapid, simple, inexpensive diagnostic means. Corneal transplantation continues to be the most effective approach for the treatment of severe fungal keratitis. Early surgery, especially LK, can be considered if aggressive topical therapy does not achieve early disease control.