Background: Outbreaks of post-cataract surgery endophthalmitis are often due to infection with Gram-negative organisms including Pseudomonas aeruginosa, which usually has poor visual prognosis due to its virulence factors and intrinsic resistance to antimicrobial agents. This work was concerned with investigation of outbreak of post phacoemulsification surgeries that took place at an eye care center, at 1-day period in Egypt. Retrospective case series study had been carried out with participants of six patients who underwent phacoemulsification surgeries. The clinical settings and treatment outcomes were described. Results: The results showed isolation of Pseudomonas aeruginosa, multidrug-resistant strain in all cases; five vitreous samples and one anterior chamber fluid sample. No evisceration or enucleation had to be done to any of these eyes in 8-month follow-up period. The source of outbreak was most probably the reused-reprocessed cassette of the phacoemulsifier machine. No pseudomonas strains could be isolated from other environmental samples. Conclusion: Early diagnosis and prompt recall of suspected cases and applying outbreak control measures helped to achieve good visual and anatomic outcomes. Reprocessing and reuse of single use devices should not be done, except after following the international regulations and the manufacturers' information on the appropriate decontamination process to allow reuse, including cleaning, disinfection, and method of sterilization.

This study aimed to assess air quality in operating rooms (OR) , expressed as colony forming units (