الفهرس 
AcknowledgementsOnly 14 pages are availabe for public view
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Abstract
The current study was done in microbiological unit of Clinical pathology department, Assiut university hospital. This study included 219 isolates from various clinical specimens (blood, urine, sputum and pus) obtained from admitted patients to different departments in Assiut university hospital in Years from June 2018 to May 2019 with age ranged from (18- 60 years old). Out of these 219 isolates there were 27 Pseudomonas isolates and 42 Acinetobacter isolates which submitted to: Identification of the organism by direct gram stain film, morphology on MacConkey agar and biochemical tests. Screening test by antibiotic sensitivity test by Disk diffusion method and Vitek2 Phenotypic confirmatory methods for detection of: -ESBL (chromID™ ESBL agar, Combined Disk Method, ESBL E-Test) -AmpC (Three-dimensional test Disk approximation test, Boronic acid disk test) -Carbapenemase enzyme (ChromID® CARBA SMART Agar (CARBA/OXA), Modified Hodge Test (MHT), Rapidec Carba NP Test. Detection of metallo beta-lactamases by: Combined disc test (MP/MPI) meropenem and meropenem –EDTA E-test (IP/IPI) imipenem and imipenem- EDTA The aim of our study is: Detection of frequency of each type of Pseudomonas isolates and Acinetobacter isolates. Comparison between vitek2 and disk diffusion method for screening drug susceptibility of B-lactamases.
1- Comparison between different phenotypic screening and confirmatory methods for detection of B-lactamases. Determination of the Distribution of different beta lactamases among
Pseudomonas and Acinetobacter isolates. -The results of this study revealed that:
There were 24 Pseudomonas isolates were suspected to ESBL producers, 23 isolates were suspected to AmpC producers and 25 isolates were suspected to carbapenemase producers. There were 21 Acinetobacter isolates were suspected to ESBL producers, 31 isolates were suspected to AmpC producers and 27 isolates were suspected to carbapenemase producers The result of Vitek 2 compact and disk diffusion method for antibiotic susceptibility tests were almost the same. 24 Pseudomonas isolates were suspected ESBL by screening with antibiotic susceptibility test and confirmed by phenotypic confirmatory tests (chromID™ ESBL agar, combined disk test and ESBL E-Test). 23 Acinetobacter isolates which were suspected ESBL by screening with antibiotic susceptibility test, were confirmed by phenotypic confirmatory tests (chromID™ ESBL agar, combined disk test and ESBL E-Test). Among the phenotypic methods in pseudomonas we noted that the combined disk test showed the same sensitivity (82.4%) for detection of ESBL as the chromogenic media which showed the lowest specificity (42.9%). Among the phenotypic methods in Acinetobacter we noted that the combined disk test showed the same sensitivity (100%) and specificity (13.3%) for detection of ESBL. Detection of AmpC there were 25 Pseudomonas and 20 Acinetobacter isolates were suspected for AmpC resistance by screening with antibiotic sensitivity test and subjected to phenotypic confirmatory
tests by Disk approximation test (DAT) , Boronic acid test and Three- dimensional test which was the standard phenotypic test and we found that Disk approximation test detected Amp C beta-lactamase carrying bacteria with higher sensitivity than Boronic acid test, but Boronic acid test has higher specificity (86.7%) than that of Disk approximation test (80%) in Pseudomonas. Among the phenotypic methods in Acinetobacter isolates, we noted that the Disk approximation test showed higher sensitivity for detection of AmpC than Boronic acid disk test but the Boronic acid disk test has a higher specificity (60%).Detection of carbapenemase producer among pseudomonas and acinetobacter we found that among the phenotypic tests for carbapenemase detection, The chromID® CARBA SMART agar ( 96.3%, 97.1%) detected the highest percentage of carbapenemase producer among the phenotypic confirmatory tests, then Carba NB ( 77.8%, 82.9%)and lastly MHT(70.4%, 71.4%).As regard detection of metallo beta lactamases by using E-test as a gold standard we found that, the combined disk test is a reliable test for detection of metallo beta lactamases as it showed 66.7%sensitivity, but it shows specificity 86.7% in pseudomonas. The combined disk test is a reliable test for detection of metallo-beta lactamases as it showed 87.5% sensitivity, but it shows specificity 36.4% in Acinetobacter. The most common type of beta lactamases in Pseudomonas were the ESBL 63% and the AmpC 63% and lastly metallo beta lactamse 29.6%. The most common type of beta lactamases in Acinetobacter was the metallo beta lactamse 57.1% then the AmpC 35.7% and lastly ESBL 19%.
The most common type of beta lactamases in Pseudomonas was ESBL (18.5%), ESBL and AmpC and Carbapenemases (18.5%), AmpC (3.7%), ESBL and Carbapenemases (33.3%), Carbapenemases (11.1%).There were no ESBL isolates alone, (4.7%) ESBL and AmpC, (2.3%) ESBL and AmpC and Carbapenemases, (14.2%) AmpC, (11.9%) ESBL and Carbapenemases, (28.5%) Carbapenemases among Acinetobacter isolates.