Study of the Gene Expression of aacC1 Gene in Acinetobacter baumannii that Responsible for Aminoglycoside Resistance

Abstract

Acinetobacter baumannii carries modifying enzymes, are resistant to many broad-spectrum antibiotic, including: - Amikacin, Tobramycin and Gentamycin (Aminoglycoside), the genes that encode the Aminoglycosides enzymes was aadA1 and aacC1 genes confer resistance to anti-group aminoglycoside.

Two Hundred clinical samples were collected from different sources of infection included (50 sample of blood, 55 sample of sputum, 50 samples of Urine , 10 samples of wound, 10 samples of burn ,10 samples of throat swab and 15 samples of body fluid from plural infusion).

Clinical samples were cultured in different media, Blood agar, MacConkey agar and CHROM agar and incubated at 37°C for 24–48 h. for diagnosis used biochemical tests including (oxidase and catalase) and microscopic examination, for final detection using Vitik2 compact system and API 20E . After identification we obtained 40 isolates of Acinetobacter baumannii, including 14 isolates from blood (35%) , 15 isolates from sputum (38%) , 4 isolates from wound infection (10%) , 4 isolates from Urine (10%) , only one isolate from Throat swabs, Burn and plural effusion fluid (2.5%)

Minimum Inhibitory Concentrations detection to antibiotic. All isolates displayed resistant to Ticarcycllin 55%, Pipracillin / Tazobactam 55%, Trimethoprim 52.5%, Ticarciliin / Clavulanic acid 52%, Ceftazidim 52%, Cefipim52% , Imipinem 52%, Ciprofloxacin 52% , Gentamycin 40% , pipracillin 37% , Meropinem 37% , Colistin 15 % , Tobramycin 10% , Minocycline 5%.

Genotypic detection of aacC1gene using polymerase chain reaction (PCR). The results was appeared all isolates (20) have aacC1 gene in percentage (100%) with molecular weight 465 base pair. Gene expression detection for aacC1gene by using Real Time Polymerase Chain Reaction (RT-PCR). The results of gene expression for aacC1gene was increasing when the isolate was treated by gentamycin antibiotic in concentration 1.2 µl/ ml.

Acinetobacter baumannii has aacC1 resistance gene in (100%). The results also showed that there was an increase in the gene expression of aacC1 gene after treatment with Gentamycin