Rapid Disc Diffusion Antibiotic Susceptibility Testing for Gram Negative Non- fermenters: Pseudomonas and Acinetobacter

Document Type : New and original researches in the field of Microbiology.

Authors

1 Assistant Professor Medical Microbiology & Immunology Department, Faculty of Medicine, Alexandria University, Egypt

2 Medical Microbiology and Immunology, Faculty of Medicine, Alexandria University

3 Lecturer of Medical Microbiology and Immunology Department, Alexandria University, Egypt

Abstract

Background: Non fermentative Gram-negative bacilli are opportunistic pathogens associated with serious hospital infections. Antibiotic susceptibility pattern of these pathogens has become unpredictable and disc diffusion remains the preferred standardized, most used and cost-effective method according to the CLSI and EUCAST. However, the method is standardized for overnight incubation (16-18 hrs.), which delays result an extra day. Objective: The aim of our study was to examine the possibility and accuracy of manually interpreting disc diffusion zone diameter results for clinical isolates of Acinetobacter species and Pseudomonas species, after 6 hrs. and 8 hrs. incubation, in comparison to the standard overnight incubation. Results: This study showed that there was a good level of agreement for early zone measurement of Acinetobacter AST after 6 hrs., which improved with extending incubation to 8 hrs. As for Pseudomonas species, zone measurement at 8 hrs. resulted in minor errors of 10.4% and very major errors of 1.2%, which just exceeds the guideline allowed limits. Conclusion: Rapid antibiotic susceptibility testing and interpretation was manually possible. Both Acinetobacter and Pseudomonas were measurable at 8 hrs., but Acinetobacter measurements were more accurate with minimal errors, which makes it a promising cost-effective method for rapid delivery of AST results for Acinetobacter. These findings are worthy of further studies, to determine the best incubation time that would allow rapid results delivery with minimal errors for different bacterial species.

Keywords

Main Subjects

Files

Share

How to cite

Statistics