Minimum Inhibitory Concentrations of Standard and Novel Antimicrobials for Isolates from Bacterial Keratitis

Abstract

Based on systemic breakpoint data, resistance to commonly used antimicrobials was apparent. Meropenem is a potentially effective agent for ophthalmic use, with low MICs throughout all the bacterial subgroups. Tigecycline and linezolid showed good activity against particular groups and may be useful for treating bacterial keratitis resistant to current antimicrobials. Of the fluoroquinolones, moxifloxacin showed the lowest MICs and resistance for both Gram-positive and -negative bacteria.

Orlans HO, Hornby SJ, Bowler IC (2011) In vitro antibiotic susceptibility patterns of bacterial keratitis isolates in Oxford, UK: a 10-year review. Eye Jan 21 [Epub ahead of print] PMID 21252952

“…This type of study provides valuable information for ophthalmologists treating suspected bacterial keratitis in the clinical setting. In this study, they found that the most commonly isolated bacteria were Staphylococci (40.1%), followed by Pseudomonas species (28.5%), other Gram-negative species (17.2%), Streptococci (7.1%), and Corynebacteriacea (6.0%), which is similar to previous studies [8]. Between the first and second time periods there was a significant increase in the number of coagulase-negative staphylococci (CNS).…”

“…The introduction of antimicrobials that are used increasingly to treat systemic infection into ophthalmic practice is an opportunity to improve treatment. It has been shown, for example, that an agent such as meropenem has excellent in vitro activity against commonly recognised pathogens [8]. In addition, the combination of meropenem and ciprofloxacin appear to be a good combination option (in vitro) against S. aureus and P. aeruginosa, with synergy in 20-25% and additivity in 55-60% of these isolates.…”

Genetic Characterization Indicates that a Specific Subpopulation of Pseudomonas aeruginosa Is Associated with Keratitis Infections

“…We have shown previously in bacterial keratitis, using a general linear multivariate model, a weak (14%) but significant association between the MIC of the antimicrobial prescribed and clinical outcome, defined by the ratio of healing time to ulcer size (24). We also demonstrated the importance of the bacterial type and particular antimicrobial used for treatment (24,52). The importance of this relationship is underlined by the finding that although 99% of P. aeruginosa isolates were found, for example (using systemic breakpoint data), to be susceptible to ceftazidime, ciprofloxacin, levofloxacin, and moxifloxacin, the association between clinical outcome and MIC for P. aeruginosa was 10% (24,52).…”

Sensibilidad antibiótica de bacterias obtenidas de queratitis e infecciones intraoculares en la Fundación Oftalmológica de Santander (FOSCAL), Floridablanca, Colombia

“…Consideramos que debe evaluarse la inclusión de nuevos antibióticos en el arsenal terapéutico disponible para uso tópico en oftalmología; algunos de dichos antibióticos ya están disponibles en presentaciones oftálmicas en otras partes del mundo y otros todavía no se encuentran en forma de colirio como el imipenem, el meropenem, la besifloxacina, la tigeciclina y la linezolida (10). De igual manera, se deben estudiar más detalladamente las interacciones y posibles sinergias de los diferentes antimicrobianos (27).…”