ABSTRACT
PURPOSE: Systemic doxycycline has been prescribed to reduce inflammation and enhance corneal healing in bacterial keratitis. Topical autologous serum drops (ASD) containing doxycycline following oral supplementation may additionally confer an anti-bacterial effect. The potential of this supplementation was evaluated by determining the in vitro susceptibility of bacterial keratitis isolates to doxycycline. METHODS: The minimum inhibitory concentrations (MICs) of doxycycline against 100 bacterial keratitis isolates were determined using Etests. Twenty-seven Staphylococcus aureus, ten coagulase-negative Staphylococci, six Streptococcus pneumoniae, seven viridans group streptococci, seven other Gram-positive bacteria, nineteen Pseudomonas aeruginosa, eight Serratia marcescens, four Moraxella spp., two Haemophilus spp., and ten other Gram-negative bacteria isolates were tested. MICs of doxycycline were compared to a serum standard concentration of doxycycline (SSCD) of 4 µg/mL and concentrations that would be found in 50% and 20% serum component clinical preparations of ASD, corresponding to 50% SSCD (2 µg/mL) and 20% SSCD (0.8 µg/mL), respectively. MICs equal to or less than these values were used to deem a bacterial isolate susceptible. RESULTS: For Gram-positive bacteria, susceptibilities to SSCD, 50% SSCD, and 20% SSCD were 86%, 65%, and 60%, respectively. For Gram-negative bacteria, susceptibilities to SSCD, 50% SSCD, and 20% SSCD were 37.2%, 23.3%, and 11.6%, respectively. Chi-squared analyses comparing Gram-positive and Gram-negative susceptibilities showed significantly greater susceptibility of Gram-positive bacteria at all three tested MICs (<0.0001, <0.0001, <0.0001). CONCLUSIONS: Our data suggest that autologous serum drops containing theoretic concentrations of doxycycline may provide an additional anti-bacterial effect in the treatment of bacterial keratitis, especially for Gram-positive bacterial keratitis compared to Gram-negative bacterial keratitis.
ABSTRACT
OBJECTIVE: To determine the frequency of herpes zoster ophthalmicus (HZO) and assess risk factors for developing uncommon ocular manifestations of laboratory-verified HZO. DESIGN: Retrospective cohort study. METHODS: The frequency of HZO out of all herpes zoster cases was calculated using International Classification of Diseases codes for patients seen at the University of Pittsburgh Medical Center from January 1, 2004 to October 31, 2021. We also collected demographic and clinical data of patients with HZO identified by polymerase chain reaction (PCR) detection of varicella zoster virus from January 1, 2011 to December 31, 2020. RESULTS: The frequency of HZO from 2004 to 2021 in all ages was 4.2% and ranged from 2.7% to 6.7% annually, with a consistent increase of 2.9% from 2012 to 2021. After the live zoster vaccine became available in 2008, the frequency of HZO decreased by 5.1% from 2008 to 2012 in patients aged 60 and older. Among 50 cases of PCR-verified HZO, 62% represented clinically-common ocular manifestations, mostly comprised of 13 cases of keratitis and 10 cases of anterior uveitis. Fifteen cases of acute retinal necrosis (ARN) represented the majority of uncommon HZO manifestations (38%), which were significantly more likely to occur in immunosuppressed patients (unadjusted odds ratio 4.55, 95% confidence interval 1.29-13.83). CONCLUSIONS: The overall frequency of HZO from 2004 to 2021 was 4.2% and has increased annually since 2012. Uncommon ocular manifestations of PCR-verified HZO, mostly comprised of ARN, were more likely to occur in immunosuppressed patients.
