الفهرس 
CHAPTER I: AcinetobacterOnly 14 pages are availabe for public view
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Abstract
Acinetobacter isolates are challenging pathogens responsible for serious nosocomial infections. They can survive in the clinical environment with great resistance to disinfectants, antibiotics, moist and dry conditions as; they can use different metabolic sources and have the ability to form biofilms.
Acinetobacter has transformed from a monodrug-resistant to a multidrug-resistant or even pandrug-resistant organism.Numerous mechanisms may lead to this resistance, and the active efflux mechanism is an important factor for MDR in Acinetobacter. Since it is the unique efflux pump to Acinetobacter, the AdeABC system is important in mediating drug-resistance, which belongs to the RND multidrug efflux system.
The aim of this work was to determine the role of AdeB gene among Acinetobacter isolated from ICUs of Menoufia University Hospitals
This study was performed in Clinical Pathology Department, Faculty of Medicine, Menoufia University during the period from May 2016 to October 2018. Clinical samples were collected and processed according to standard microbiological methods.
Antimicrobial susceptibility testing for Acinetobacter isolates was performed by disk diffusion method against Ceftazidime (30 μg), Trimethoprim-sulfamethoxazole (1.25/23.75μg)cefepime (30μg), amikacin (30μg), cefotaxime (30μ), ciprofloxacin (5μg), pipracillin/ tazobactam (100/10μg), doxycycline (30μg), cefpodoxime (30μg), impenem (10μg), meroneam (10μg), tetracycline (3 μg) and gentamicin (10μg). Acinetobacter isolates were tested for minimum inhibitory concentration (MIC) of three antimicrobial agents (imipenem, ciprofloxacin and gentamicin) by agar dilution method before and after addition of efflux pump inhibitor (CCCP) Results were interpreted according to CLSI 2018.
All clinical isolates of Acinetobacter were tested for the presence of AdeB gene by real time PCR.
A total of 50 Acinetobacter isolates were obtained from different clinical samples. Acinetobacter infections were more common among males (54 % %), with average age 45years. Patients were stayed in hospitals for more than 7 days (65.7%), used antibiotic (55.7%), exposed to invasive procedures (72.9%) and had associated co-morbidities (87.1%).
The highest rate of clinical Acinetobacter isolation was from respiratory secretions (70%).
Antimicrobial susceptibility tests using disk diffusion method revealed that clinical Acinetobacter isolates were highly resistant to resistant to ampicillin salbactam (92%), trimethoprim-salfamethoxazole (86%), tetracycline(84%) ceftazidime,cefotaxime (82%) for each , ,piperacillin -tazobactam,ciprofloxacin (80%) doxycycline, gentamicin (78%), meropenem (30%) and impenem (28%).
About (%80) of clinical isolates of Acinitobacter were MDR or XDR of all Acinetobacter isolates were MDR or XDR. In this study the role of the efflux pump AdeB gene among the clinical Acinetobacter isolates was determined and we found that there was significant increase in AdeB gene expressed in relation to susceptible cases we used CCCP as efflux pump inhibitor and we found that addition of CCCP at concentration10 μg/ml reduced MIC of imipenem, ciprofloxacin and gentamicin
AdeB gene expression was evaluated in isolates resistant to impinem, ciprofloxacin and gentamicin after addition of CCCP and there was significant relation between AdeB expression and reduction in MIC .Isolates which show fold reduction equal or greater than 2 folds show higher expression of the gene (decreased CT of AdeB gene) (mean 11.92±1.56 for impinem, 14.70 ± 4.22 for ciprofloxacin and 14.70 ± 4.22 for gentamicin) than other isolates with fold reduction less than 2.
Considering to the restoration of antibiotic activity with the addition of CCCP only 21.4% of isoltes resistant to impinem, 17.9 % of isolates resistant to ciprofloxacin and 17.9% of isolates resistant to gentamicin convert to susciptble so the gene expression is important cause for multi-drug resistance in Acinetobacter but it alone is insufficient to develop multi-resistance, and so, multiple causes must be considered.