POLYMICROBIAL KERATITIS : PSEUDOMONAS AERUGINOSA AND STAPHYLOCOCCUS EPIDERMIDIS

The purpose of this study is to emphasize the importance of coordinated work with the microbiology laboratory in the diagnosis, treatment and management of infectious keratitis.

This study was prepared in the light of the information obtained during the diagnosis, observation and treatment of the patient who was hospitalized in Dışkapı Yıldırım Beyazıt Training and Research Hospital in March 2024 with suspicion of infectious keratitis.

This study describes a patient with clinically suspected infectious keratitis. For microbiologic diagnosis, corneal scrapings were taken before the patient started treatment. The corneal scrapings were inoculated in appropriate media at the point of care and preparations were prepared for direct microscopic examination. The media and preparations prepared for gram staining were sent to the microbiology laboratory for identification of the causative agent(s) and, if necessary, for antimicrobial susceptibility testing.

In microbiology laboratory, rare PMNL and rare gram positive cocci were observed in gram stained preparations. Two different microorganisms were identified in the cultured media. These are Pseudomonas aeruginosa and Staphylococcus epidermidis. Antimicrobial susceptibility testing was performed for both pathogens. Susceptibility results for Pseudomonas aeruginosa were susceptible (S) for amikacin and meropenem and susceptible, increased exposure(I) for ceftazidime, ciprofloxacin, levofloxacin and piperacillin tazobactam. Susceptibility results for Staphylococcus epidermidis were susceptible(S) to erythromycin and trimethoprim sulfamethoxazole and resistant(R) to methicillin, levofloxacin and penicillin G.

Various microorganisms such as bacteria, fungi, protozoa and viruses can cause infectious keratitis. Polymicrobial keratitis caused by two or more microorganisms accounts for 2% to 15% of infectious keratitis. Microbiologic diagnosis has an important place in terms of identifying the pathogen and using the appropriate antimicrobial agent for the pathogen.

Corneal scraping is an important part of the diagnosis of infectious keratitis. Direct microscopic examination of the preparation prepared from corneal scrapings can provide fast and therapeutically guiding information. If there is growth in the culture prepared from the corneal scraping, identification of the pathogen and antimicrobial susceptibility tests play an important role in the course of empirical treatment. Identifying the causative agent and using antibiotics in the right spectrum will also be beneficial in terms of combating antibiotic resistance, which is a major problem. Therefore, the clinician should be in constant communication with the microbiology laboratory in the diagnosis, treatment and management of infectious keratitis.