Anti-Infective Treatment and Resistance Is Rarely Problematic with Eye Infections.

The treatment of eye infections is very different than treating other body infections that require systemic anti-infectives. Endophthalmitis, keratitis, conjunctivitis, and other ocular infections are treated with direct injection and with topical drops directly to the infection site. There are no anti-infective susceptibility standards to interpret treatment success, but the systemic standards can be used to guide ocular therapy if the concentration of anti-infective in the ocular tissue is assumed to be higher than the concentration in the blood serum. This Perspective describes: (1) eye infections, (2) diagnostics of eye infections, (3) anti-infective treatment of eye infections, (4) anti-infective resistance of ocular pathogens, and (5) alternative anti-infective delivery and therapy. The data, based on years of clinical and laboratory research, support the premise that ocular infections are less problematic if etiologic agents are laboratory-diagnosed and if prompt, potent, anti-infective therapy is applied. Anti-infective susceptibility should be monitored to assure continued therapeutic success and the possibility of new-found resistance. New delivery systems and therapies may be helpful to better treat future ocular infections.

Insect Fungus Metarhizium robertsii Is a Rare Causative Agent of Keratitis.

PURPOSE: This study aimed to describe a case of keratitis secondary to Metarhizium robertsii, a soil-dwelling fungus with typical insect pathogenicity. METHODS: A Case report. RESULTS: A 58-year-old man with a ocular history of soft contact lens overwear, poor contact lens hygiene, and ocular exposure to ground well water supplying his house was referred to our university practice for a central corneal ulcer with 40% thinning. Same-day rapid microscopic detection with Giemsa stain identified the presence of many hyphae elements, and he was ultimately diagnosed with M. robertsii keratitis. The patient's course involved severe and progressive corneal thinning that stabilized over a 3-month course of antifungal therapy. CONCLUSIONS: Metarhizium robertsii seems more aggressive than other forms of fungal keratitis; therefore, this infection may be watched more closely with the risk for quick progressive corneal thinning, even while on antifungal management.

Speciation and Antibiotic Susceptibilities of Coagulase Negative Staphylococci Isolated from Ocular Infections.

Coagulase-negative staphylococci (CoNS) are frequently occurring ocular opportunistic pathogens that are not easily identifiable to the species level. The goal of this study was to speciate CoNS and document antibiotic susceptibilities from cases of endophthalmitis (n = 50), keratitis (n = 50), and conjunctivitis/blepharitis (n = 50) for empiric therapy. All 150 isolates of CoNS were speciated using (1) API Staph (biochemical system), (2) Biolog GEN III Microplates (phenotypic substrate system), and (3) DNA sequencing of the sodA gene. Disk diffusion antibiotic susceptibilities for topical and intravitreal treatment were determined based on serum standards. CoNS identification to the species level by all three methods indicated that S. epidermidis was the predominant species of CoNS isolated from cases of endophthalmitis (84-90%), keratitis (80-86%), and conjunctivitis/blepharitis (62-68%). Identifications indicated different distributions of CoNS species among endophthalmitis (6), keratitis (10), and conjunctivitis/blepharitis (13). Antibiotic susceptibility profiles support empiric treatment of endophthalmitis with vancomycin, and keratitis treatment with cefazolin or vancomycin. There was no clear antibiotic choice for conjunctivitis/blepharitis. S. epidermidis was the most frequently found CoNS ocular pathogen, and infection by other CoNS appears to be less specific and random. Antibiotic resistance does not appear to be a serious problem associated with CoNS.

The Prevalence of Bacteria, Fungi, Viruses, and Acanthamoeba From 3,004 Cases of Keratitis, Endophthalmitis, and Conjunctivitis.

PURPOSE: The definitive identification of ocular pathogens optimizes effective treatment. Although the types of ocular pathogens are known; there is less definitive information on the prevalence of causative infections including viruses, fungi, and protozoa, which is the focus of this retrospective laboratory review. METHODS: Data used for laboratory certification were reviewed for the detection of bacteria, viruses, fungi, and protozoa, from patients with infectious keratitis, endophthalmitis, and conjunctivitis. The main outcome parameter was laboratory-positive ocular infection. RESULTS: The distribution of infectious agents for keratitis (n=1,387) (2004-2018) was bacteria 72.1% (Staphylococcus aureus 20.3%, Pseudomonas aeruginosa 18%, Streptococcus spp. 8.5%, other gram-positives 12.4%, and other gram-negatives 12.9%), Herpes simplex virus 16%, fungi 6.7%, and Acanthamoeba 5.2%. For endophthalmitis, (n=770) (1993-2018), the bacterial distribution was coagulase-negative Staphylococcus 54%, Streptococcus spp. 21%, S. aureus 10%, other gram-positives 8%, and gram-negatives 7%. The distribution for conjunctivitis (n=847) (2004-2018) was Adenovirus 34%, S. aureus 25.5%, Streptococcus pneumoniae 9%, Haemophilus 9%, other gram-negatives 8.8%, other gram-positives 6%, coagulase-negative Staphylococcus 4.5% and Chlamydia 3.2%. CONCLUSION: An updated monitoring of ocular pathogens creates an awareness of the different infectious etiologies and the importance of laboratory studies. This information can determine treatment needs for infectious ocular diseases.