In vitro activity of T4 bacteriophage on uropathogenic e. coli

Abstract

Bacteriophage is a virus that infects bacteria and can kill a bacterial cell or integrate its nucleic acid (DNA or RNA) into the host bacterial cell. One of the phage important medical applications is using it as an alternative approach to treatment of infections byresistant pathogenic bacteria. This research aims to find the susceptibility of drug resistant uropathogenic E. coli towards the T4 phage. The study involved collection of resistant uropathogenic E. coli (UPEC)toward (Ceftazidime, Gentamicin, Trimethoprim/Sulfamethoxazole, Ampicillin, Amoxicillin with Clavulanic Acid and Ciprofloxacin,) isolatesfrom (Hospital Tengku Ampuan Afzan) HTAA, Kuantan, Pahang during a 4 months period (from 01/September/2015 to 31/December/2015). Re-identification of UPEC isolates was done by scientifically approved conventional diagnostic methods. To storeisolates for further laboratory procedures, approved long term and short term bacterial storage methods were followed. All UPEC isolates were checked for antimicrobial susceptibility test by the Kirby&Bauer method and by the extended spectrum beta-lactamase (ESBL) screening test. The quantitation of T4 bacteriophage was done at first by the plaque assay on reference E.coli strain ATCC25922. In the plaque assay for UPEC, serial log dilutions of T4 phage (1 × 10-1, 1 × 10-2, 1 × 10-3 ,1 × 10-4 ,1 × 10-5 ,1 × 10-6 ,1 × 10-7 ,1 × 10-8 ,1 × 10-9 and 1 × 10-10(were incubated with UPEC by using the double agar layer technique. Countable plaques wereformed for all UPEC isolates in plates inoculated withphage dilutions of 1 × 10-6and 1 × 10-7. To determine the phage Minimal Inhibitory Concentration (phage MIC), the microbroth dilution method wasperformed. The phage MIC for the bacterial isolates was~1 × 105/mLwhich is the lowest phage concentration or highest dilution which gave a clear broth (no bacterial growth). Serotyping of UPEC H & O antigenswasdone bystandard agglutination method.The percentage distributionof UPEC serotypeswasCAN55 (14%), MSHS94(6%) and MSHS23a(10%) and unknown serotype (70%). In conclusion, the T4 phage concentration of 1 × 105/mLis regarded as the phage MIC for all the tested UPEC strains showing a lytic effect against UPEC.