Bacterial isolates and antimicrobial susceptibility pattern of ocular infection at a tertiary referral hospital in the South of Italy

Purpose: The present study aimed to determine the prevalence of bacterial and fungal infections of the eye and also to assess the antibiotic susceptibility pattern of bacterial isolates at a tertiary referral eye care hospital in Bari, Italy.

Methods: Two hundred seventy three samples collected during a 2-year observation period. Culture, Gram's stain, potassium hydroxide mount and occasionally Giemsa staining was done for the clinical specimens. Antibiotic susceptibility testing was performed for bacterial growth.

Results: Out of 273 samples processed, 236 (86.4%) yielded growth: of them, 183 (77,5%) were bacterial, 26 (11%) fungal, and 23 (9,7%) specimens showed the presence of Acanthamoeba. Among bacterial infections, 99 (54.5%) bacterial isolates were Gram-positives, and 82 (44.8%) were Gram-negatives. Among Gram positives, Tigecycline showed the greatest susceptibility (93.8%), followed by Linezolid (97%) and Daptomycin (95.18%). Gram negative bacteria strains were susceptible to Imipenem (95%), Meropenem (98,5%) and Amikacin (91%) Multidrug in vitro resistance (resistance >3 classes of antibiotics) was found in 45 Gram positive (63%). and 33 Gram negative (44%).

Conclusion: Conjunctival specimens yielded mainly bacterial growth with Staphylococcus species being the predominant isolate followed by Pseudomonas species. Findings from the current analysis evidence a substantial level of in vitro resistance to ≥3 antibiotics.