Phenotypic detection of extended spectrum -lactamase and Metallo -lactamase production by Gram negative uropathogens after exposure to gamma radiation

Abstract

Eighty-five uropathogen isolates were collected and differentiated on the basis of their Gram stain reaction. Among the collected isolates, 25 (29.4%) were Gram positive cocci and 60 (70.6%) were Gram negative bacilli. Antibiotic susceptibility profile towards 15 different antibiotics concluded that impenime (IMP), amikacin (AK) and Pipperacillin/tazobactam (TZP) were the most effective against Gram negative; while linezolid (LZD), and vancomycin (VA) were the most potent against Gram positive. The highly drug resistant isolates were identified as Pseudomonas aeruginosa and Klebsiella pneumoniae using 16srRNA; the two strains were subjected to different doses of gamma-radiation and the sub lethal dose of both strains was 5.0 kGy. The D 10 values were recorded (1.2 and 1.1 kGy) for P. aeruginosa and K. pneumoniae), respectively. In addition, gamma-irradiation technique decreases the resistance of K. pneumoniae towards IMP and the resistance of P. aeruginosa towards more than one antibiotic (TZP, AZM and CIP). The results also, revealed that both of the tested strains had the ability to produce Extended Spectrum β-lactamase (ESBL) before and after gamma-radiation but only P. aeruginosa had the ability to produce Metallo β-lactamase (MBL), that is, ESBL and MBL co-production was detected in P. aeruginosa. So, these findings must be supported by other studies on the level of genes to prove the possibility for using gamma-irradiation technique to overcome microbial drug resistance problem.

Classification and Comparison of Bacterial Resistance and Resistance Learning Against Low Dose Irradiation

“…There are explanations asserting the reason for E.Coli and Serratia strains being most susceptible to gamma irradiation. Since the relations between beta lactamase enzymes and radiation resistance are uncovered recently(Gaougaou et al 2018;Yehia et al 2020), and knowing that E.Coli and Serratia are relatively more susceptible to antibiotics linked to beta lactam mechanisms of action(Waites et al 2006;Traub 2000) one can conclude that their weak radiation resistance is connected with this matter beside the genetic differences.Although this strain of E.Coli has shown an insigni cant resistance against gamma radiation, its great adapting ability can be explained by genetic adaptation related to DNA repairs[Boiteux et al 1987;Harris et al 2009;Byrne et al 2014] as opposed to Salmonella. Also, its ability to adapt to different harsh environmental conditions such as pollution(Zhang et al 2019), makes this bacterium another considerable candidate for radiative environment investigations next to Enterobacter Aerogenes that showed the highest adaptability.…”