Evaluation of Metallo Beta Lactamase E test Results from Different Brands of Mueller Hinton Agar Plates / MBL E Test Arastirmasinda 5 Farkli Marka Muller-Hinton Agar Besiyerlerinden Elde Edilen Sonuclarin Degerlendirilmesi

Abstract

Aim: MBL E test for MBL screening in carbapenem resistant Pseudomonas aeruginosa isolates is recommended as a fast and reliable phenotypic screening test. However, as it has been put forward by some reserachers, because of variations in antibiotic susceptibility tests or MBL E test with different brands of Mueller- Hinton Agar (MHA) media, the possibility that carbapenem MIK values and MBL E test results can, therefore, be influenced by these media. To this end, we aim to determine the most suitable MHA media to be used in search for MBL E test in routine microbiology laboratories by employing five different brands of MHA media. Materials and Methods: 29 carbapenem resistant Pseudomonas aeruginosa strains isolated from hospitalised patients have been used in this study. P.aeruginosa isolates were identified by conventional methods. Imipenem and meropenem E test were used for verification of carbapenem resistance. MBL E test was used for detecting MBL production by five different brands of Mueller Hinton agar plates and the results of these tests were compared with polymerase chain reaction (PCR) results. Results: IMP, VIM, GIM, SIM and SPM type genes were found to be negative with polymerase chain reaction for 29 isolates that were resistant to carbapenem. One isolate with BBL brand MHA, two isolates with Oxoid brand MHA, 19 isolates with Himedia brand MHA, 21 isolates with Merck brand MHA, and 27 isolates with Plasmatec brand MHA gave positive results. Conclusion: The present results indicate that use of BBL or Oxoid brand MHA media, especially in laboratories without any fascilities for molecular diagnosis, can be more reliable compared to other brands.