Outbreak of Microsporidial Keratoconjunctivitis Associated With Water Contamination in Swimming Pools in Taiwan

Molecular characterization and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis in humans and domestic animals in Heilongjiang Province, China

BACKGROUND

Cryptosporidiosis and giardiasis are significant parasitic diseases shared between humans and domestic animals. Due to the close contact between humans and domestic animals in rural areas, it is important to consider the potential transmission of zoonotic parasites from infected domestic animals to humans. This investigation aimed to determine the prevalence and molecular characteristics of Cryptosporidium spp. and Giardia duodenalis in domestic animals and villagers.

METHODS

A total of 116 fecal samples from villagers and 686 fecal samples from domestic animals in Heilongjiang Province, China, were analyzed for two parasites using nested polymerase chain reaction (PCR) targeting various genetic loci and DNA sequence analysis of the PCR products.

RESULTS

By sequence analysis of the SSU rRNA gene, the prevalence of Cryptosporidium in humans was 0.9% (1/116), with one species of C. parvum (n = 1) detected; among domestic animals, the prevalence was 2.6% (18/686), with five species identified: C. suis (n = 7) and C. scrofarum (n = 7) in pigs, C. meleagridis (n = 1) in chickens, C. andersoni (n = 1) in cattle, and C. canis (n = 2) in foxes. C. parvum and C. canis were further subtyped as IIdA19G1 and XXa4 on the basis of gp60 gene. Regarding G. duodenalis, based on the SSU rRNA, bg, gdh, and tpi genes, the prevalence in domestic animals was 5.1% (31/608), with three assemblages identified: A (n = 1) in pigs, D (n = 1) in foxes, and E (n = 27) in geese, cattle, pigs, ducks, and sheep, along with mixed infection of A + E (n = 1) in one pig and B + E (n = 1) in one sheep. No G. duodenalis was detected in humans (0/116).

CONCLUSIONS

The present results show that no overlap of subtypes between animals and villagers was found in Cryptosporidium spp. and G. duodenalis, indicating a minor role of domestic animals in infecting humans in this population. However, the presence of zoonotic protozoa in domestic animals highlights the need for special attention to high-risk individuals during close contact with domestic animals.

Microsporidial keratoconjunctivitis - first outbreak in Japan

BACKGROUND

Most cases of microsporidial keratoconjunctivitis are found in the Southern hemisphere. Our purpose was to investigate the first outbreak of microsporidial keratoconjunctivitis in Japan among healthy, immunocompetent soccer players from the same team during a 1-month period.

CASE PRESENTATION

This study is an observational case series. The medical records were analyzed for five cases with microsporidial keratoconjunctivitis who presented within September 2022. All five cases were males between 28 and 36 years old. These previously healthy individuals belonged to the same football team. Their eyes were considered susceptible to contaminated water or dirt from the turf at game and practice sites. All cases involved unilateral conjunctivitis, with scattered round white lesions that showed positive fluorescein staining in the corneal epithelium. All cases experienced diminution of vision in the affected eye. In three cases, direct smears showed spores of approximately 2-3 μm in diameter. Polymerase chain reaction (PCR) analysis of corneal scrapes revealed partial amplification of microsporidial 18 S ribosomal RNA gene in four cases. Sequences of PCR products from all four cases showed 100% identity with strains of Vittaforma corneae previously reported from an outbreak in Singapore. All cases were treated with topical therapy, including voriconazole, fluorometholone, and levofloxacin. Four eyes underwent corneal scraping. After treatment, all eyes healed without residual opacities.

CONCLUSIONS

Only a few sporadic case reports of this disease have previously been reported in Japan. We detected V. corneae in our case series, representing what appears to be the first outbreak of microsporidial keratoconjunctivitis in Japan. Exposure to contaminated water or soil, in addition to inadequate sanitary facilities, represents a potential source of infection. Further investigations to clarify the characteristics of microsporidia seem warranted.

Microsporidia-Associated Anterior Uveitis After Keratoconjunctivitis

OBJECTIVE

The aim of this study was to describe the clinical features and management of uveitis associated with microsporidial keratoconjunctivitis (MKC).

METHODS

The medical records of clinically diagnosed or microbiologically proven patients with MKC between July 2016 and August 2021 were reviewed. Patients with documented evidence of keratic precipitates (KPs) or anterior chamber cells were analyzed for their demography, clinical features, and treatment. Patients with microsporidial stromal keratitis and herpes simplex virus keratouveitis were excluded from the study.

RESULTS

Of the 2212 patients reviewed within the study period 171 of 172 eyes (7.7%) had documented evidence of KPs and/or anterior chamber cells. The patients' mean age was 43.8 ± 13.8 years, and there were more men (n = 120). The mean duration of appearance of KPs was 6.9 ± 5.5 days, and 28% (n = 48 of 171) appeared on the day of presentation. Superficial punctate keratitis was central and diffuse in 48 and 49 patients, respectively. The treatment was either lubricant alone (45.3%; 78 eyes) or combined with topical steroids (54.7%; 94 eyes). The mean duration of the resolution was longer in the "corticosteroid" than "no corticosteroid" group: KPs: 15.3 ± 6.5 days versus 12.3 ± 5.8 days ( P = 0.007) and superficial punctate keratitises: 15.4 ± 9.4 days versus 11.7 ± 6.2 days ( P = 0.01). The presenting visual acuity with a pinhole was 0.26 ± 0.26 (logMAR) and it improved to 0.03 ± 0.07 on resolution ( P < 0.0001, paired t test).

CONCLUSIONS

Uveitis after MKC is a self-limiting entity that often resolves without corticosteroid. One must exercise caution in using steroids in the presence of active corneal lesions.

Waterborne transmission of protozoan parasites: a review of worldwide outbreaks - an update 2017-2022

The current study presents a comprehensive review of worldwide waterborne parasitic protozoan outbreaks reported between 2017 and 2022. In total, 416 outbreaks were attributed to the waterborne transmission of parasitic protozoa. Cryptosporidium accounted for 77.4% (322) of outbreaks, while Giardia was identified as the etiological agent in 17.1% (71). Toxoplasma gondii and Naegleria fowleri were the primary causes in 1.4% (6) and 1% (4) of outbreaks, respectively. Blastocystis hominis, Cyclospora cayetanensis, and Dientamoeba fragilis were independently identified in 0.72% (3) of outbreaks. Moreover, Acanthamoeba spp., Entamoeba histolytica, Vittaforma corneae, and Enterocytozoon bieneusi were independently the causal agents in 0.24% (1) of the total outbreaks. The majority of the outbreaks (195, 47%) were reported in North America. The suspected sources for 313 (75.2%) waterborne parasitic outbreaks were recreational water and/or swimming pools, accounting for 92% of the total Cryptosporidium outbreaks. Furthermore, 25.3% of the outbreaks caused by Giardia were associated with recreational water and/or swimming pools. Developing countries are most likely to be impacted by such outbreaks due to the lack of reliable monitoring strategies and water treatment processes. There is still a need for international surveillance and reporting systems concerning both waterborne diseases and water contamination with parasitic protozoa.

Metagenomic sequencing for investigation of a national keratoconjunctivitis outbreak, Israel, 2022

BackgroundEpidemics of keratoconjunctivitis may involve various aetiological agents. Microsporidia are an uncommon difficult-to-diagnose cause of such outbreaks.AimDuring the third quarter of 2022, a keratoconjunctivitis outbreak was reported across Israel, related to common water exposure to the Sea of Galilee. We report a comprehensive diagnostic approach that identified Vittaforma corneae as the aetiology, serving as proof of concept for using real-time metagenomics for outbreak investigation.MethodsCorneal scraping samples from a clinical case were subjected to standard microbiological testing. Samples were tested by calcofluor white staining and metagenomic short-read sequencing. We analysed the metagenome for taxonomical assignment and isolation of metagenome-assembled genome (MAG). Targets for a novel PCR were identified, and the assay was applied to clinical and environmental samples and confirmed by long-read metagenomic sequencing.ResultsFluorescent microscopy was suggestive of microsporidiosis. The most abundant species (96.5%) on metagenomics analysis was V. corneae. Annotation of the MAG confirmed the species assignment. A unique PCR target in the microsporidian rRNA gene was identified and validated against the clinical sample. The assay and metagenomic sequencing confirmed V. corneae in an environmental sludge sample collected at the exposure site.ConclusionsThe real-time utilisation of metagenomics allowed species detection and development of diagnostic tools, which aided in outbreak source tracking and can be applied for future cases. Metagenomics allows a fully culture-independent investigation and is an important modality for public health microbiology.

Past, present, and prospects in microsporidial keratoconjunctivitis- A review

Ocular microsporidiosis comprises two entirely different spectra of disease as keratoconjunctivitis and stromal keratitis. Microsporidial keratoconjunctivitis (MKC) has been increasingly reported in the past two decades, probably due to raised awareness, simpler diagnostic procedures, and a better understanding of the clinical presentation. It is characterized by the presence of raised, coarse, punctate, multifocal, round to oval, greyish-white corneal epithelial lesions which usually evolve into nummular scars before resolution. Conjunctivitis seen is non-purulent and of mild-moderate intensity, with mixed papillary-follicular reaction. The mode of transmission and pathogenesis is poorly understood. Despite lack of inflammatory response, uncommon associations reported were- endotheliitis, corneal edema, limbitis, uveitis, and sub-epithelial infiltrates. There has been no consensus on the management of MKC. It varies from the use of multiple antimicrobial agents to simple lubricants. The majority of the disease goes underdiagnosed or misdiagnosed and treated as adenoviral keratoconjunctivitis, with topical steroids or anti-virals empirically. Changing trends have been noticed in the pattern of infection, possibly with increasing evidence of Vittaforma corneae as causative organisms, previously reported to cause stromal keratitis. An elaborate review of the past and present literature on MKC is provided in this review article, along with gaps in knowledge, and future directions of research.

Current Therapy and Therapeutic Targets for Microsporidiosis

Microsporidia are obligate intracellular, spore-forming parasitic fungi which are grouped with the Cryptomycota. They are both opportunistic pathogens in humans and emerging veterinary pathogens. In humans, they cause chronic diarrhea in immune-compromised patients and infection is associated with increased mortality. Besides their role in pébrine in sericulture, which was described in 1865, the prevalence and severity of microsporidiosis in beekeeping and aquaculture has increased markedly in recent decades. Therapy for these pathogens in medicine, veterinary, and agriculture has become a recent focus of attention. Currently, there are only a few commercially available antimicrosporidial drugs. New therapeutic agents are needed for these infections and this is an active area of investigation. In this article we provide a comprehensive summary of the current as well as several promising new agents for the treatment of microsporidiosis including: albendazole, fumagillin, nikkomycin, orlistat, synthetic polyamines, and quinolones. Therapeutic targets which could be utilized for the design of new drugs are also discussed including: tubulin, type 2 methionine aminopeptidase, polyamines, chitin synthases, topoisomerase IV, triosephosphate isomerase, and lipase. We also summarize reports on the utility of complementary and alternative medicine strategies including herbal extracts, propolis, and probiotics. This review should help facilitate drug development for combating microsporidiosis.

Waterborne protozoan outbreaks: An update on the global, regional, and national prevalence from 2017 to 2020 and sources of contamination

The aim of this review is to identify the worldwide trend of waterborne protozoan outbreaks and how it varies between geographic regions during the period from 2017 to 2020. Data about waterborne protozoan outbreaks were gathered and stratified by continent, country, water source, and protozoan species associated with the outbreak. The highest prevalence of waterborne protozoan outbreaks was reported in developed countries. Out of 251 outbreaks reported worldwide during the studied period, 141, 51 and 24 outbreaks were recorded in the USA, UK, and New Zealand, respectively. These outbreaks were mainly associated with Cryptosporidium (192 outbreaks) and Giardia (48 outbreaks). Cyclospora cayetanensis, Dientamoebafragilis and Toxoplasma gondii were associated with 7 outbreaks. One outbreak was associated with each of Blastocystis hominis, Entamoeba histolytica, Microsporidia or Naegleria fowleri. This data suggests large discrepancies in the number of outbreaks reported between geographic regions, with most outbreaks recorded in developed countries. Differences in the prevalence of outbreaks between countries are likely attributed to the availability of diagnostic capabilities and surveillance programs to monitor water contamination with pathogenic protozoa. More attention and concerted efforts are required to improve water safety and to alleviate the impact of waterborne protozoan infections. Appropriate surveillance of water contamination with protozoa can enable public health officials to identify source of contamination and implement the necessary measures to limit transmission and prevent outbreaks.

Microsporidia-induced stromal keratitis: a new cause of presumed immune stromal (interstitial) keratitis

BACKGROUND AND OBJECTIVE

To describe the clinical features, diagnosis and management of immune stromal keratitis/interstitial keratitis (IK) associated with microsporidial epithelial keratitis.

METHODS

Between October 2020 and January 2021, medical records of IK patients microbiologically proven as microsporidia from samples collected from corneal epithelium on smear examination, and/ or molecular analysis were reviewed. Demography, clinical profile and treatment were analysed. Real-time PCR (RT-PCR) for adenovirus (ADV), Epstein-Barr virus (EBV), herpes simplex virus (HSV) and varicella-zoster virus (VZV) was done.

RESULTS

Twenty of 152 (13%) microbiologically proven cases of microsporidial keratitis were diagnosed as IK during the study period, the mean age and duration of symptoms were 35.7±11.4 years and 46.3±27.7 days, respectively. Half had predisposing risk factors, like trauma; and 30% had prior recurrences. One-fourth of patients were using antivirals on presentation. Characteristic presentations included disciform keratitis(n=12), incomplete/complete ring(n=5), and combination(n=3), along with variable subepithelial infiltrates (n=14). All cases had stromal oedema, with an intact epithelium and fine pigment dusting on endothelium. Corneal epithelial scrapings had scanty microsporidia spores in smears of 17/20 (85%), and pan-microsporidial DNA was identified in 14/20 (70%), with Vittaforma corneae by sequencing in 11/20 (55%). Other viruses detected were ADV (14,70%), VZV (2,10%), EBV (1,5%) and HSV (1,5%). Rapid resolution of inflammation and oedema within 2 weeks of starting steroids was seen in all cases.

CONCLUSION

Microsporidia epithelial keratitis induced stromal inflammatory keratitis; is distinguished from microsporidial keratoconjunctivitis and stromal keratitis, by characteristic clinical features, and response to topical steroids.

Ocular microbial diversity, community structure, and function at high altitude

PURPOSE

To investigate the composition and function of ocular surface microbiome in healthy people from different altitudes.

METHODS

Thirty-two healthy people living in a high altitude region and 30 sex- and age-matched individuals living in a low altitude region were enrolled. Samples were collected from the lower conjunctival sac of one randomly chosen eye for each participant. 16S rRNA sequencing was conducted to study the bacterial community composition and predict gene function using PICRUSt software.

RESULTS

Microbial diversity and richness was significantly decreased in samples from highlanders as calculated by Abundance-based Coverage Estimator (ACE) index, Chao1 index, and observed-species index (all p < 0.01). Principle coordinate analysis (PCoA) suggested significantly distinct clustering of the conjunctival sac bacterial communities between two groups (p = 0.03), especially the dominant genera. The relative abundances of Corynebacterium, Staphylococcus, and Anaerococcus were significantly enriched in highlanders, while those of Pseudomonas and Massilia were significantly decreased as compared with lowlanders (p < 0.01). In the functional annotation analysis, we found that 74 gene pathways, mainly in metabolism, differed in abundance. Pathways related to immune system diseases and infectious diseases were also enriched in highlanders.

CONCLUSION

The composition and function of ocular surface microbiome in highlanders were distinct from those of lowlanders and our study may provide a reference catalog of the healthy conjunctival microbiome in highlanders.

Microsporidial Keratitis Related to Water Exposure: A Case Series

The objective of this retrospective study was to present a series of cases involving the rare ocular disease of microsporidia keratitis treated at a private practice clinic and describe the details regarding specific water exposure, clinical course, voriconazole treatment, and increased prevalence of this infection in Augusta, Georgia, USA. Our analysis was based on the accumulated data from all patients (n=15) diagnosed with microsporidia keratitis at our private practice clinic; the clinical course of three cases is discussed in detail in this article. Specific environmental exposures were documented in 10 patients. All patients self-reported that they had no acquired immunodeficiency. In all cases, patients had complete resolution of active symptoms after receiving treatment with 1-2% topical voriconazole, with an approximate average primary treatment duration of 40.1 ± 17.1 days (median: 40 days, range: 14-70 days). None of the patients reported any clinically significant adverse effects from therapy.

There have been increasing reports about this emerging infectious pathogen, particularly in Asia. However, there is limited data in the literature on the etiology, pathogenesis, and treatment of microsporidia-caused ophthalmic diseases. In this case series, we highlight the strong correlation of our patients' condition with specific types of water exposure in the USA as well as the complete resolution of active disease in all our patients as a result of monotherapy with topical voriconazole.

Sequelae of microsporidial keratoconjunctivitis and its management

Purpose:

To characterize the sequelae of microsporidia keratoconjunctivitis (MKC) and outline its management.

Methods:

Retrospective analysis of microbiologically proven MKC returned with persistent disease between January 2015 and December 2019 was done. Demographics, clinical features, management, and outcome were analyzed.

Results:

Sixteen patients (21 eyes) of 332 treated for MKC returned with the persisting disease. The mean age of 11 males (68.7%), and 5 females was 35.1 ± 12.2 years. Three-quarter of them did not have a known predisposing risk factor and one-quarter of them were referred for chronic conjunctivitis. Past medications included topical antivirals (n = 8) and topical corticosteroid (n = 6). Three predominant presentations were persistent (>3 weeks) superficial punctate keratitis (SPKs, n = 7), sub-epithelial infiltrates (SEIs, n = 13), and uveitis (n = 2). The lesions recurred in eight eyes (SPK and SEI 4 each) after a disease-free interval of 60.4 ± 40.6 days; there were 13 episodes of recurrence. Topical low potent corticosteroids (loteprednol/fluorometholone), and tacrolimus ointment 0.03% were used in 17 (80.9%) and 8 (38%) eyes, respectively, for a mean duration of 44.8 ± 31.6 and 226.8 ± 180.5 days, respectively. At follow-up, 172.3 ± 183.6 days, visual recovery was statistically significant in persistent eyes (BCVA 0.07 ± 0.07 logMAR; P < 0.00001) but, not in recurrent eyes (BCVA 0.16 ± 0.08 logMAR; P = 0.07). Five of 21 eyes were left with residual significant scar.

Conclusion:

The sequelae of microsporidial keratoconjunctivitis are not uncommon. Topical 0.03% tacrolimus ointment appeared to be an effective corticosteroid-sparing agent for the treatment of SEIs and prevention of recurrence.

Temporal trend of microsporidial keratoconjunctivitis and correlation with environmental and air pollution factors in India

Purpose:

The aim of this study was to describe the correlation between the temporal pattern of presentation of acute microsporidial keratoconjunctivitis (MKC) with meteorological parameters such as environmental temperature, rainfall, humidity, windspeed, and air pollution.

Methods:

This cross-sectional hospital-based study included 182,789 patients presenting between January 2016 and December 2019 hailing from the district of Hyderabad. Patients with a clinical diagnosis of MKC in at least one eye with an acute onset (≤1 week) of presentation were included as cases. Correlation analysis was performed with the local environmental temperature, rainfall, humidity, and windspeed (Telangana State Development and Planning Society) and air pollution (Central Pollution Control Board, Government of India).

Results:

Overall, 84 (0.05%) patients were diagnosed with acute onset MKC from the district of Hyderabad. The mean monthly prevalence in this cohort was 0.05% with peak prevalence in the months of July (0.08%), August (0.09%), September (0.12%), and October (0.08%). The environmental parameters of rainfall (r² = 0.87/P = < 0.0001), humidity (r² = 0.78/P = 0.0001), windspeed (r² = 0.38/P = 0.0321) were significantly positively correlated and the air pollution parameters such as ground level ozone (r² = 0.89/P = < 0.0001), particulate matter PM₁₀ (r² = 0.65/P = 0.0013), PM_2.5 (r² = 0.50/P = 0.0095), nitrogen dioxide (r² = 0.53/P = 0.0071), and carbon monoxide (r² = 0.69/P = 0.0008) were significantly negatively correlated with the temporal pattern of MKC in the population.

Conclusion:

Parasitic infections like MKC show a distinct temporal trend peaking during the monsoon season in the population. An increase in humidity, wind speed, and especially rainfall contributes to a higher prevalence of MKC cases during the year. An increase in ground-level ozone seems to be protective against infection.

"A prospective study on the clinical course and proposed morphological classification scheme of microsporidial keratoconjunctivitis."

Background and objective: To describe the clinical course and propose a morphological classification scheme of microsporidial keratoconjunctivitis. Methods: This is a prospective study at L V Prasad Eye Institute, Odisha, between August-January (2017-19). Patients of any age or sex, microbiologically proven as microsporidial keratoconjunctivitis were included. Demographic parameters, history, clinical course, and visual outcome were analysed. All received artificial tear substitutes till resolution and topical immunosuppressants used in cases of persisting sub-epithelial infiltrates (SEI) beyond 2 weeks. Results: Fifty-three eyes of 47 cases were included with males, 72.3%. Corneal lesions were classified into 3 morphological types- coarse, ring, and flat-topped (Type1, 2 & 3). Depending upon the location, Type 1 was further sub-divided into peripheral, paracentral, central, and diffuse (Type 1a, b, c & d). The mean age was highest in Type 3(p = .026). Risk factors and prior steroid use were most common in Type 1d. The mean duration of symptom before presentation was longest in Type 3(11.6 ± 3.65) days. Severe conjunctival congestion at presentation in more than half of the eyes were seen in Type 1a, 1b and 1d, with moderate congestion at Day14 persisting in 66.7% and 40% of eyes belonging to Type 1c and 1d, respectively. Keratic precipitates were most common in Type 2. The mean duration of resolution was longest in Type 1d (38 ± 15.87) days and shortest in type 1b (7.88 ± 2.47) days (p = .022). Persistent SEIs beyond Day 90 were seen in total of 6 (11.3%) (Type 1c & 1d- 3 each) eyes and recurrent SEIs in 7(13.2%) (Type 1c-2 & 1d- 5) eyes. The mean duration of topical steroids use was longest in Type 1d (49.3 ± 22.3) days, followed by Type 1c (28 ± 0) days. Conclusion: Microsporidial keratoconjunctivitis can have a variable clinical presentation, the course of each being different depending on the host and ocular surface factors. Though considered as a self-limiting disease, central and diffuse coarse variety (Type1c&1d) required long-term topical immunosuppressants and follow-up.

Nanocellulosics: Benign, Sustainable, and Ubiquitous Biomaterials for Water Remediation

Water is critical for all lives to thrive. Access to potable and safe water has been argued to rank top among the prerequisites for defining the standard of living of a nation. However, there is a global decline in water quality due to human activities and other factors that severely impact freshwater resources such as saltwater intrusion and natural disasters. It has been pointed out that the millions of liters of industrial and domestic wastewater generated globally have the potential to help mitigate water scarcity if it is appropriately captured and remediated. Among the many initiatives to increase access to clean water, the scientific community has focused on wastewater remediation through the utilization of bioderived materials, such as nanocellulosics. Nanocellulosics, derived from cellulose, have the advantages of being ubiquitous, nontoxic, and excellent adsorbents. Furthermore, the surface properties of nanocellulosic materials can easily be modified. These advantages make them promising materials for water remediation applications. This perspective highlights the most important new developments in the application of nanocellulosics in water treatment technologies, such as membrane, adsorption, sensors, and flocculants/coagulants. We also identify where further work is urgently required for the widespread industrial application of nanocellulosics in wastewater treatment.

Vittaforma Corneae keratoconjunctivitis: An emerging pathology among travelers returning from Southeast Asia

Microsporidium keratoconjunctivitis is an very rare disease. It is related to outbreaks in Asia due to exposure to contaminated water or soil. Microsporidium keratoconjunctivitis is a a self-limited disease, but it could have long term courses. We present the case of a 29 year old woman who started with pain, redness and blurred vision after a holiday in Singapore and did not respond to conjunctivitis treatment. PCR sequencing and PAS staining of corneal epithelial biopsy identified Vittaforma corneae as the causative organism. Treatment was initiated with corneal debridement, oral albendazol, and intensive topical voriconazole, levofloxacin and propamidine, but the conjunctival and corneal disease was only resolved 5 months later with the introduction of topical steroids to treat her severe limbitis. Suspicion of Microsporidium keratoconjunctivitis should be raised amongst ophthalmologists in unilateral keratitis with mild conjunctivitis in travelers from Asia.

Swimming Pool-Associated Vittaforma-Like Microsporidia Linked to Microsporidial Keratoconjunctivitis Outbreak, Taiwan

We analyzed 2 batches of environmental samples after a microsporidial keratoconjunctivitis outbreak in Taiwan. Results indicated a transmission route from a parking lot to a foot washing pool to a swimming pool and suggested that accumulation of mud in the foot washing pool during the rainy season might be a risk factor.

A Narrative Review of Microsporidial Infections of the Cornea

Microsporidia are a rare and commonly misdiagnosed cause of corneal infection, accounting for approximately 0.4% of cases of microbial keratitis in some populations. Ocular microsporidiosis most often presents as either microsporidial keratoconjunctivitis (MKC) or microsporidial stromal keratitis (MSK). Though these two clinical entities exhibit similar symptomology, they are distinguished from one another by the time course for disease progression, findings on slit-lamp examination, and response to medical therapy. This review summarizes the current literature on the etiology and clinical presentation of microsporidial infections of the cornea and highlights ongoing developments in available diagnostic modalities and treatment regimens.

Microbial Keratitis in Taiwan: A 20-Year Update

PURPOSE

To investigate the demographics, risk factors, microbiology, and resistance pattern at a tertiary hospital and to detect the shifting trend over 2 decades.

DESIGN

A retrospective observational case series.

METHODS

We reviewed all records of patients with microbial keratitis (MK) that were hospitalized in National Taiwan University Hospital between 2007 and 2016. Demographics, predisposing factors, pathogens, and clinical courses were compared to our previous study conducted from 1992 to 2001. Antibiotic susceptibility was compared with those conducted from 1994 to 2005.

RESULTS

The percentage of patients 60 years and older in the MK population was increasing (P = 2.1E-21). The proportion of trauma-related MK declined while MK related to chronic ocular or systemic disorders rose. The prevalence of nontuberculous mycobacteria (NTM) showed a decreasing trend (P = .0032), whereas Microsporidia has been increasingly detected. The 2 most common bacterial isolates were Pseudomonas aeruginosa (35.2%) and Staphylococcus species (13.2%). Management of these infection did not differ in common pathogens between the 2 decades. The susceptibility of Staphylococcus species to oxacillin reduced significantly (P = .002) and there was an increase in methicillin-resistant Staphylococcus aureus keratitis.

CONCLUSIONS

Contact lens wear remained the most common predisposing factor, with Pseudomonas species as the major pathogen. However, chronic disorder-related MK was on the rise along with an increasing trend of oxacillin resistance in Staphylococcus species. We found a decreasing trend in NTM keratitis while Microsporidia keratitis was considered as an emerging ocular disease. Though gram-negative isolates remained susceptible to all antibiotics tested, antibiotic resistance was more common in gram-positive isolates.