Trends in the epidemiological and microbiological profiles of infectious keratitis in southeastern Brazil

Carolina Saliba de Freitas, Marcelo Oliveira Mesquita, Mayara Seyko Kaczorowski Sasaki, Alice Zaidan Azevedo, Artur Willian Caldeira Abreu Veloso, Marco Antônio Guarino Tanure, Daniel Vítor Vasconcelos-Santos

To investigate the antibiotic susceptibility as well as the clinical, epidemiological, and microbiological profiles of microbial keratitis. This was a longitudinal retrospective study, and we retrospectively reviewed medical and laboratory records from 2015 to 2019. In total, 380 pathogens (321 bacteria and 59 fungi) were isolated from the corneas of 352 patients. Staphylococcus species (45%) were most abundant within the organisms that were isolated, followed by Pseudomonas (18.4%), fungi (15.5%), Streptococcus (7.9%), and Serratia species (3.2%). The isolated gram-positive bacteria were not resistant to amikacin or vancomycin, although 14.8% of the gram-positive isolates were resistant to ciprofloxacin (p<0.05). All the gram-negative isolates were susceptible to amikacin. Male patients represented 62.8% of the 129 cases with accessible clinical data. The mean age of the patients was 53.17 ± 21 years. The time to presentation (from onset of symptoms) was 14.9 ± 19.4 days (median: 7 days). Large ulcers (>5 mm in any dimension) were present in 49.6% (64 eyes) of the cases. The duration of treatment was 49 ± 45.9 days (median: 38 days). Direct ocular trauma was reported by 48 (37.2%) patients, and 15 patients (11.6%) reported using contact lenses. For 72 (55.8%) patients, topical treatment had been previously prescribed, and 16 (12.4%) patients reported using other classes of drugs. Hospitalizations were required for 79 (61.2%) patients, and in terms of major complications, 53 (41.1%) patients had corneal perforations. A total of 40 patients (31%) underwent tectonic penetrating keratoplasty, and 28 (21.7%) developed secondary glaucoma. A progression to endophthalmitis occurred in 8 (6.2%) patients, with 50% of those patients' (3.1% of the total) endophthalmitis evolving to evisceration. The patients' microbial keratitis was largely treated empirically, with 94 (72.9%) patients prescribed moxifloxacin and 56 (43.4%) prescribed ciprofloxacin before receiving their culture results. For the most part, our hospital treated patients with severe microbial keratitis. Despite identifying gram-positive bacteria in most of the isolates, we also frequently identified gram-negative rods and fungi. Our susceptibility results support prescribing a combination of vancomycin and amikacin as an effective empirical therapeutic regimen to treat microbial keratitis.