Ocular mycobacterial lesions in cats.

Ocular mycobacterial infections are an under-recognized cause of morbidity in the domestic cat. This study aimed to explore the distribution, histopathological appearance, and severity of feline ocular mycobacterial lesions, and to characterize the immune cell population with immunohistochemistry. Routine histological staining with hematoxylin and eosin, and Masson's trichrome, was performed to identify ocular lesions and assign an inflammation score based on the number of cells present. Acid-fast bacilli were detected with Ziehl-Neelsen, and immunohistochemistry for ionized calcium-binding adaptor protein-1 (Iba1), calprotectin, cluster of differentiation 3 (CD3), and Pax5 was undertaken on formalin-fixed paraffin-embedded tissue samples from 24 cases of ocular mycobacteriosis. Posterior or panuveitis with concurrent retinitis was identified in 20/24 cases (83%), with retinal detachment in 16/20 (80%) of these cases. Choroidal lesions had the highest median inflammation score. Ziehl-Neelsen-positive organisms were detected in 20/24 cases (83%), with the highest prevalence of acid-fast bacilli detected in choroidal lesions (16/20, 80%). Lesions were typically granulomatous to pyogranulomatous, characterized by abundant numbers of Iba1-positive macrophages, followed by calprotectin-positive granulocytes and monocytes, fewer T cells, and rarer B cells. However, where iritis was identified, inflammation was typically lymphoplasmacytic (11/16 cases, 69%). Where diagnostic testing was performed, tuberculosis (ie, infection with Mycobacterium bovis, Mycobacterium microti, or a nonspeciated Mycobacterium tuberculosis-complex pathogen) was diagnosed in 20/22 cats (91%), with Mycobacterium lepraemurium infection identified in the other 2/22 cats (9%). These results suggest the choroid is the primary site of lesion development in most cases of feline ocular mycobacteriosis, and inflammatory changes are associated with the presence of mycobacteria localized to ocular tissues.

Differential Antimicrobial Efficacy of Preservative-Free Contact Lens Disinfection Systems against Common Ocular Pathogens.

Microbial keratitis is a devastating disease that can cause eye damage and blindness and can be the result of infections by several common ocular pathogens. Importantly, some of these pathogens, such as Acanthamoeba, are particularly unsusceptible to biocides in common contact lens care solutions. Therefore, the disinfection efficacy of preservative-free (PF) disinfection systems against bacteria, fungi, and Acanthamoeba trophozoites and cysts should be assessed as products with the most potential to be efficacious against resistant organisms. PF disinfection systems were analyzed for antimicrobial efficacy. These were the one-step (hydrogen peroxide-based) Clear Care and Clear Care Plus systems and the two-step (povidone-iodine-based) Cleadew system. Stand-alone challenges using bacteria, fungi, and Acanthamoeba were prepared according to the International Standards Organization method 14729. These same challenges were also conducted in the presence of the following contact lenses: Boston RGP, Acuvue Oasys, Biofinity, Ultra, and 2-week PremiO. All challenges were performed at the manufacturer's recommended disinfection time. All preservative-free disinfection systems demonstrated similarly high rates of antimicrobial efficacy when challenged with bacteria or fungi, with or without lenses. However, both Clear Care and Clear Care Plus demonstrated significantly greater disinfection efficacy against Acanthamoeba trophozoites and cysts, with and without lenses (P < 0.05). Cleadew efficacy was impacted by the addition of contact lenses, whereas Clear Care/Clear Care Plus maintained similar efficacies in the absence or presence of lenses. While both hydrogen peroxide and povidone-iodine are highly effective against bacteria and fungi, hydrogen peroxide maintains significantly greater disinfection capabilities than povidone-iodine against all forms of Acanthamoeba. IMPORTANCE Understanding the most efficacious products will allow clinicians to best communicate to patients and consumers the safest products on the market to reduce adverse events, including microbial keratitis, during contact lens use.

A sensitive and rapid bioanalytical method for the quantitative determination of luliconazole in rabbit eye tissues using UPLC-MS/MS assay.

Luliconazole (LCZ) is a novel antifungal imidazole with broad-spectrum and high susceptibility of Aspergillus and Fusarium are the dominant species of fungal keratitis, may potentially be a new medical treatment option for ocular fungal infection. To evaluate LCZ distribution in ocular tissues after topical application for the development of ophthalmic delivery system, it is important to have a bioanalytical method for measuring the drug concentrations in different ocular tissues and aqueous humor (AH). A selective and sensitive ultrahigh performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) method was developed for the quantification of LCZ in rabbit ocular tissues, including conjunctiva, cornea, AH, iris, lens, vitreous humor (VH), retinal choroid and sclera, using lanoconazole as internal standard (IS). Chromatographic separation was achieved on a Xterra MS, C18 column (2.1 × 50 mm, 3.5 µm) using mobile phase with formic acid solution (0.2%, v/v): acetonitrile (50:50, v/v) at a flow rate of 0.2 ml/min, and the run time was 2.5 min. Detection was performed using the transitions 354.1 → 150.3 m/z for LCZ and 320.1 → 150.3 m/z for IS by positive ion electrospray ionization in multiple reaction monitoring (MRM) mode. Method validation was conducted in accordance with U.S. Food and Drug Administration's regulatory guidelines for bioanalytical method validation. The calibration curves were linear over the concentration range from 2.80 ng/ml to 2038 ng/ml for conjunctiva, cornea and sclera, 2.09 ng/ml to 1019 ng/ml for AH, 2.09 ng/ml to 509.5 ng/ml for iris, 2.09 ng/ml to 203.8 ng/ml for retinal choroid and VH, 2.04 ng/ml to 101.9 ng/ml for lens, with all the squared correlation coefficients (r2) more than 0.99. The accuracy of the method was within the acceptable limit of 89.34%∼112.78% at the lower limit of quantification and other concentrations, Inter-day and intra-day precision values, expressed in terms of RSD (%), in all tissues were within 15% at all concentrations. The mean recoveries of LCZ in rabbit ocular tissues was 84.85%∼100.52%. No interference was found due to matrix components. Luliconazole was stable during the stability studies, including autosampler stability, benchtop stability, freeze/thaw stability and long-term stability. The method was successfully applied to the ocular pharmacokinetic and tissues distribution studies of LCZ in rabbit after topical administration of LCZ ophthalmic drug delivery system.

The crested caracara (Caracara plancus) eye: Morphologic observations and results of selected diagnostic tests.

PURPOSE: To provide a descriptive investigation about relevant features of the crested caracara's eye (Caracara plancus) and bony orbit, as well as provide data for ophthalmic tests. METHODS: Morphological observations and the following diagnostic tests were performed: Schirmer tear test (STT), conjunctival flora evaluation, corneal touch threshold (CTT), intraocular pressure (IOP), central corneal thickness (CCT), B-mode ocular biometry, palpebral fissure length (PFL), and corneal diameter (CD) in 19 healthy birds, plus two macerated skulls. Not all birds were used for each test. RESULTS: STT: 7.84 ± 3.05 mm/min; CTT: 2.46 ± 1.10 cm; IOP: 19.18 ± 3.07 mmHg; CCT: 0.31 ± 0.02 mm; PFL: 13.32 ± 1.06 mm; CD: 10.26 ± 2.43 mm; Axial globe length: 1.89 ± 0.06 cm; Anterior chamber depth: 0.27 ± 0.06 cm; Lens axial length: 4.55 ± 0.06 cm; Vitreous chamber depth: 1.2 ± 0.07 cm. The most frequent conjunctival bacterial isolates were Corynebacterium sp. (10/23.8%), Staphylococcus sp. (9/21.42%), Streptococcus sp. (7/16.6%), and E. coli (7/16.66%). The large lateral part of the palatine bone likely plays a role in the ventral protection of the globe against the impact of prey. Observed results are generally reflective of increased body mass compared to other Falconiformes, with values approaching those of similar sized Accipitriformes. CONCLUSIONS: These data may help veterinarians recognize peculiar morphologic features and perform a more accurate diagnosis of eye diseases of this avian species.

Interactions between staphylococcal enterotoxins A and D and superantigen-like proteins 1 and 5 for predicting methicillin and multidrug resistance profiles among Staphylococcus aureus ocular isolates.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant (MDR) S. aureus strains are well recognized as posing substantial problems in treating ocular infections. S. aureus has a vast array of virulence factors, including superantigens and enterotoxins. Their interactions and ability to signal antibiotics resistance have not been explored. OBJECTIVES: To predict the relationship between superantigens and methicillin and multidrug resistance among S. aureus ocular isolates. METHODS: We used a DNA microarray to characterize the enterotoxin and superantigen gene profiles of 98 S. aureus isolates collected from common ocular sources. The outcomes contained phenotypic and genotypic expressions of MRSA. We also included the MDR status as an outcome, categorized as resistance to three or more drugs, including oxacillin, penicillin, erythromycin, clindamycin, moxifloxacin, tetracycline, trimethoprim-sulfamethoxazole and gentamicin. We identified gene profiles that predicted each outcome through a classification analysis utilizing Random Forest machine learning techniques. FINDINGS: Our machine learning models predicted the outcomes accurately utilizing 67 enterotoxin and superantigen genes. Strong correlates predicting the genotypic expression of MRSA were enterotoxins A, D, J and R and superantigen-like proteins 1, 3, 7 and 10. Among these virulence factors, enterotoxin D and superantigen-like proteins 1, 5 and 10 were also significantly informative for predicting both MDR and MRSA in terms of phenotypic expression. Strong interactions were identified including enterotoxins A (entA) interacting with superantigen-like protein 1 (set6-var1_11), and enterotoxin D (entD) interacting with superantigen-like protein 5 (ssl05/set3_probe 1): MRSA and MDR S. aureus are associated with the presence of both entA and set6-var1_11, or both entD and ssl05/set3_probe 1, while the absence of these genes in pairs indicates non-multidrug-resistant and methicillin-susceptible S. aureus. CONCLUSIONS: MRSA and MDR S. aureus show a different spectrum of ocular pathology than their non-resistant counterparts. When assessing the role of enterotoxins in predicting antibiotics resistance, it is critical to consider both main effects and interactions.

The ocular pyogranulomatous lesion in a Gentoo penguin (Pygoscelis papua) from the Antarctic Peninsula: evaluation of microbiological and histopathological analysis outcomes.

In this study, it was aimed to present the results of microbiological, cytological, histopathological, and immunohistochemical analyses of ocular samples from an Antarctic (Ardley Island, King George Island) Gentoo penguin chick (Pygoscelis papua) with a pyogranulomatous lesion in the right eye. Samples were taken from both the healthy left eye and the lesion in the right eye. Conventional culture methods and phenotypic and molecular tests were used for bacterial isolation and identification, respectively. None of the isolates could be identified phenotypically. As a result, four of the five isolates obtained from the right eye were considered to belong to putative novel bacterial species and taxa as their similarity to GenBank data was below 98.75%. The isolates were considered to be Pasteurellaceae bacterium, Corynebacterium ciconiae, Cardiobacteriaceae bacterium, Actinomyces sp., and Dermabacteraceae bacterium. The only isolate from the left eye was identified as Psychrobacter pygoscelis. The cytological analysis demonstrated cell infiltrates composed mostly of degenerate heterophils, reactive macrophages, plasma cells, lymphocytes, and eosinophils. Based on histopathological findings, the lesion was defined as a typical pyogranulomatous lesion. Immunohistochemistry demonstrated that the granuloma was positive for TNF-α, IL-4, MMP-9, IL-1ß, and IL-6. This is the first documented report of the unilateral pyogranulomatous ocular lesion in a Gentoo penguin chick, living in its natural habitat in Antarctica. This report also describes the isolation of four bacteria from the infected eye, which are considered to belong to novel Genus, species, or taxa. The primary bacterial pathogen that caused the ocular lesion was not able to be detected and remains unclear.

Ocular tuberculosis in a calf.

BACKGROUND: Bovine tuberculosis is a chronic inflammatory disease that causes granuloma formation mainly in retropharyngeal, tracheobronchial, mediastinal lymph nodes and lungs of bovines. The presence of these lesions in other tissues such as the eyeball is very rare and difficult to diagnose. This study describes macroscopic and microscopic pathological findings in a calf with ocular and meningeal tuberculosis. CASE PRESENTATION: March 2019, an eight-month-old Holstein Friesian calf was identified in a dairy farm located in central Mexico with a clinical cough, anorexia, incoordination, corneal opacity and vision loss. At necropsy, pneumonia, lymphadenitis, meningitis, and granulomatous iridocyclitis were observed. The histopathological examination revealed granulomatous lesions in lung tissue, lymph nodes, meninges and eyes with the presence of acid-fast bacilli associated with Mycobacterium spp. CONCLUSION: To the best of our knowledge, this is the first report that describes macroscopic and microscopic pathological findings of ocular tuberculosis in cattle. This report highlights the importance of considering bovine tuberculosis in the differential diagnosis of corneal opacity and loss of vision in cattle.

Clinical ophthalmological diagnostic description of 10 healthy sugar gliders (Petaurus breviceps) and prevalence of ocular-related presentations in a larger hospital population.

OBJECTIVE: To provide reference values for ocular examination and diagnostics in ophthalmologically normal sugar gliders (Petaurus breviceps). To retrospectively determine the prevalence of ocular diseases in sugar gliders presenting to a single institution. ANIMALS: Ten client owned and 106 previously evaluated sugar gliders. PROCEDURE: A descriptive study evaluated sugar gliders presented to Colorado State University's Avian, Exotics, and Zoological Medicine Service (CSU-AEZ) from August-2019 to January-2020. A complete ophthalmic examination including Schirmer tear test II (STT II), phenol red threat test (PRTT), intraocular pressure (IOP) via rebound tonometry, fluorescein, and rose bengal stain was performed under anesthesia. Conjunctival aerobic culture swabs and cytology were collected prior to ophthalmic evaluation. A retrospective review of medical records of sugar gliders presented to CSU-AEZ from 2008 to 2018 for ocular disease was performed. RESULTS: Mean values ± standard deviation for selected diagnostics included the following: STT II: 2.2 ± 6.7 mm/min; PRTT: 0 ± 0 mm/15 s; IOP: 12 ± 2.6 mm Hg. Fluorescein and rose bengal staining highlighted corneal abrasions secondary to tear testing. The three most common conjunctival bacterial isolates cultured were Staphylococcus spp. (3/20, 15%), Coryneform spp. (3/20, 15%), and unidentified Gram-positive cocci (3/20, 15%). Retrospective analysis revealed ocular diseases to be the third most common abnormality resulting in sugar glider presentations (13/106, 12.3%). CONCLUSION: This descriptive study gives reference values for IOP, conjunctival microbiology, and cytology for sugar gliders. STT II and PRTT provide little clinical value in sugar gliders. The retrospective study revealed that ocular abnormalities, often secondary to dental disease, are a common reason for presentation.

Molecular and phenotypic characterization of methicillin-resistant Staphylococcus pseudintermedius from ocular surfaces of dogs and cats suffering from ophthalmological diseases.

Methicillin-resistant Staphylococcus pseudintermedius (MRSP) have recently emerged as a major therapeutic challenge in small animal medicine because of their antimicrobial multidrug resistance and their role as nosocomial pathogens. This study focused on the prevalence, molecular characteristics and antimicrobial resistance pheno- and genotypes of MRSP isolated from conjunctival swabs of dogs and cats. Conjunctival swabs were collected from 72 dogs and 24 cats suffering from conjunctivitis/blepharitis, keratitis or uveitis and screened for the presence of MRSP. S. pseudintermedius was isolated from 38 (39.6 %) of all samples. Three (7.9 %) S. pseudintermedius isolates were confirmed as MRSP. They harboured the mecA gene and originated from dogs. One MRSP isolate was from a case of uveitis while the other two MRSP isolates originated from cases of conjunctivitis/blepharitis. All MRSP isolates were subjected to broth microdilution and whole genome sequencing (WGS). Resistance and virulence genes, multilocus sequence (MLS), spa, dru and SCCmec types were deduced from WGS data. Two of the three MRSP isolates, IMT360/16 and IMT515/16, shared the same MLS type (ST71), spa type (t02), dru type (dt9a), SCCmec type (II-III), and indistinguishable multidrug resistance pheno- and genotypes, including resistance to ß-lactams (blaZ, mecA), erythromycin and clindamycin (erm(B)), streptomycin (aphA3), gentamicin (aacA-aphD), enrofloxacin (mutations in grlA and gyrA), tetracycline (tet(K)), and trimethoprim (dfrG)/sulfamethoxazole. The third isolate, IMT1670/16, differed in all those characteristics (MLST (ST1403), dru type (dt10h), SCCmec type (IVg), except the spa type (t02). In addition, isolate IMT1670/16 carried a different tetracycline resistance gene (tet(M)) and was susceptible to erythromycin and clindamycin.

Ocular basidiobolomycosis - Rare presentation: A case report.

Basidiobolus ranarum is an uncommon pathogen in ocular infections. It has been previously reported from subcutaneous and gastrointestinal infections. Here, we report a rare case of ocular infection caused by B. ranarum. A 21-year-old male patient presented with visual loss and pain in the right eye due to corneal abscess following an injury while welding. KOH mount performed was indicative of fungal hyphae. Fungal culture revealed growth of B. ranarum. Meanwhile, the patient was treated with antifungal (topical natamycin and oral ketoconazole) along with total corneal transplantation. B. ranarum is a fungus very uncommonly causing ocular pathogenesis. This results in diagnostic confusion leading to poor treatment outcomes. Hence, a mycology laboratory has to be aware about this fungus and need to consider it as a differential diagnosis in patients with infectious corneal abscess.

Pathogenesis and diagnostic features of brain and ophthalmic damage produced by Clostridium perfringens type D epsilon toxin.

Clostridium perfringens type D epsilon toxin (EXT) causes an important neurologic disorder of sheep, goats and, rarely, cattle. The disease can occur in peracute, acute, subacute, and chronic forms. High circulating levels of ETX produce vasculocentric brain lesions, in which microvascular endothelial injury results in diagnostically useful perivascular and intramural extravasations of plasma protein, especially in sheep, and less frequently in goats. With lower toxin doses, a more protracted clinical course tends to occur, particularly in sheep, leading to focal, bilaterally symmetrical, necrotic foci in certain brain regions. Although these morphologic features usually permit the diagnostic pathologist to make a definitive etiologic diagnosis, there are many aspects of the pathogenesis of these cerebral lesions that are not completely understood. ETX has also been shown to produce microvascular damage in the retina of rats, resulting in severe, diffuse vasogenic edema, similar to that found in brains exposed to this neurotoxin. The pathoclisis and vascular theories offer alternative explanations of the differential susceptibility of different brain regions to the same neurotoxic insult.

Ocular Microbiota and Intraocular Inflammation.

The term ocular microbiota refers to all types of commensal and pathogenic microorganisms present on or in the eye. The ocular surface is continuously exposed to the environment and harbors various commensals. Commensal microbes have been demonstrated to regulate host metabolism, development of immune system, and host defense against pathogen invasion. An unbalanced microbiota could lead to pathogenic microbial overgrowth and cause local or systemic inflammation. The specific antigens that irritate the deleterious immune responses in various inflammatory eye diseases remain obscure, while recent evidence implies a microbial etiology of these illnesses. The purpose of this review is to provide an overview of the literature on ocular microbiota and the role of commensal microbes in several eye diseases. In addition, this review will also discuss the interaction between microbial pathogens and host factors involved in intraocular inflammation, and evaluate therapeutic potential of targeting ocular microbiota to treat intraocular inflammation.

Connect between gut microbiome and diseases of the human eye.

Implicating dysbiosis of gut microbiome in digestive tract diseases/diet-related diseases (obesity, inflammatory bowel disease, enterocolitis, diabetes, etc.) may be expected. However, when gut microbiome dysbiosis is implicated in extraintestinal diseases like cancers, muscular dystrophy, mental disorders, vaginosis, etc., it is all the more challenging. An additional challenge would be to ascertain the role of gut microbiome in ocular diseases, which are as remote as the brain. The present review highlights studies that establish the connect between gut microbiome dysbiosis and inflammatory ocular diseases such as uveitis, bacterial keratitis, fungal keratitis, etc.

First Record of the Water Mold Achlya bisexualis (Saprolegniaceae) Isolated from Ornamental Fish in South Africa.

The order Saprolegniales (Class Oomycota) is a group of fungus-like eukaryotic microorganisms that have been associated with infections in fish and fish eggs. Infections with microorganisms from this order are clearly evident because they have a cotton wool-like appearance. The aim of this study was to characterize and identify an oomycete that was isolated from the eye of an Orange Blotched Peacock Cichlid Aulonacara sp. A sample of cotton wool-like mycelia was isolated and single-spore isolations were conducted. Molecular characterization and phylogenetic analysis of the ITS1-5.8-ITS2 rDNA region for all isolates were used for species identification. Following molecular identification, one isolate was used to culture and characterize the reproductive structures. Physiological characterization entailed incubating the isolate on potato dextrose agar (PDA) at five different temperatures, ranging from 5°C to 25°C, to monitor growth rates. A multiple sequence alignment showed 100% similarity between all of the single-spore isolates and alignment with other Achlya bisexualis strains. Long, coarse hyphae with zoosporangia and gemmae typical of the order Saprolegniales were observed with an optimal growth rate at 25°C. The oomycete that was isolated from an Orange Blotched Peacock Cichlid was identified as A. bisexualis, the first record of this species in South Africa.

A case report of disseminated nocardiosis with ocular involvement in a myasthenia gravis patient and literature review.

BACKGROUND: Nocardiosis is a rare and life-threatening opportunistic infection in immunocompromised patients. Myasthenia gravis (MG) patients are potentially at risk of nocardia infection because of the use of immunosuppressive agents. To date, only 7 patients with MG have been reported to have nocardiosis. Disseminated nocardiosis with ocular involvement has not been reported in MG patients. CASE PRESENTATION: A 66-year-old man with MG who was receiving treatment with methylprednisolone and azathioprine was found to have a respiratory infection. He also had heterogeneous symptoms with skin, brain and ocular manifestations. Nocardia bacteria verified by the culture of puncture fluid, and a diagnosis of disseminated nocardiosis was made. Except for left eye blindness, the patient completely recovered from the disease with combination antibiotic therapy. To further understand nocardiosis in patients with MG, we reviewed the previous relevant literature. According to the literature, this is the first report of disseminated nocardiosis with ocular involvement in an MG patient. CONCLUSIONS: MG patients with immunosuppressant treatments are potentially at risk of a rare nocardia infection, and a favourable prognosis can be achieved through early diagnosis and appropriate antibiotic therapy.