Evaluation of the Lytic Activity of Various Phage Cocktails Against, ESBL-Producer, Non-Producer and Carbapenem-Resistant Escherichia coli Isolates

• Published in: Indian journal of microbiology 2023-06, Vol.63 (2), p.208-215
• Main Authors: Uskudar-Guclu, Aylin, Yalcin, Suleyman, Unlu, Sezin, Mirza, Hasan Cenk, Basustaoglu, Ahmet
• Format: Article
• Language: English
• Subjects: Bacterial diseases; Biomedical and Life Sciences; Burst size; E coli; Latency; Life Sciences; Lysis; Medical Microbiology; Microbiology; Original Research Article; Phages; Thermal stability
• ISSN: 0046-8991; 0973-7715
• DOI: 10.1007/s12088-023-01074-9

Bacteriophages have been proposed as an alternative therapy for the treatment of bacterial infections. This research aims to determine the lytic activity of bacteriophage-cocktails (BC) against carbapenem-resistant (CR-EC), ESBL-producer (EP-EC), and non-producer (NP-EC) E. coli isolates. Related resistance genes in 87 E. coli isolates were screened by PCR. The efficacies of BCs were determined by spot test and lytic zones were evaluated from fully-confluent to opaque. MOIs of the BCs were compared for fully-confluent and opaque lytic zones. BCs were also evaluated in terms of their biophysical characteristics including latency, burst size, pH and temperature stabilities. Among EP-EC, 96.9% of the isolates carry bla CTX-M , 25% of them bla SHV and 15.6% of them carry bla TEM . All CR-EC isolates carried bla OXA-48 , but not bla KPC and bla NDM . CR-EC isolates were the least susceptible for the each of four BCs. MOIs for ENKO, SES and INTESTI-phage forming fully-confluent zone in E. coli isolates EC3 (NP-EC), EC8 (EP-EC) and EC27 (NP-EC), respectively were 10, 100 and 1, respectively. MOIs for ENKO, SES and INTESTI opaque zone in EC19 (EP-EC), EC10 (EP-EC), EC1(NP-EC), respectively were 0.01, 0.01, 0.1 PFU/CFU, respectively. The MOI for PYO-phage forming a semi-confluent zone in EC6 (NP-EC) isolate was 1 PFU/CFU. The phages were thermally stable and tolerant to a wide pH range. Comparison of MOIs according to lysis zone characteristics demonstrated that the activities of phages in phage cocktails vary depending on the characteristics of each bacterial host.