Isolation and Identification of Escherichia coli O157:H7 Lytic Bacteriophage from Environment Sewage.

Escherichia coli O157:H7 is one of the pathogenic bacteria causing foodborne disease. The use of lytic bacteriophages can be a good solution to overcome the disease. This study is aimed at isolating lytic bacteriophages from environmental sewage with E. coli O157:H7 bacterial cells. The sample used in this study was eight bacteriophages, and the technique used in identifying E. coli O157:H7 carriers of the stx1 and stx2 genes was PCR. The double layer plaque technique was used to classify bacteriophages. Plaque morphology, host specificity, and electron micrograph were used to identify the bacteriophages. The result obtained plaque morphology as a clear zone with the largest diameter size of 3.5 mm. Lytic bacteriophage could infect E. coli O157:H7 at the highest titer of 10 × 108 PFU/mL. Bacteriophages have been identified as Siphoviridae and Myoviridae. Phage 3, phage 4, and phage 8 could infect Atypical Diarrheagenic E. coli 1 (aDEC1) due to their host specificity. The Friedman statistical tests indicate that lytic bacteriophage can significantly lyse E. coli O157:H7 (p = 0.012). The lysis of E. coli O157:H7 by phage 1, phage 2, phage 3, and phage 5 bacteriophages was statistically significant, according to Conover's posthoc test (p < 0.05). The conclusion obtained from this study is that lytic bacteriophages from environmental sewage could lyse E. coli O157:H7. Therefore, it could be an alternative biocontrol agent against E. coli O157:H7 that contaminates food causing foodborne disease.

The Analysis of OmpA and Rz/Rz1 of Lytic Bacteriophage from Surabaya, Indonesia.

A good strategy to conquer the Escherichia coli-cause food-borne disease could be bacteriophages. Porins are a type of ß-barrel proteins with diffuse channels and OmpA, which has a role in hydrophilic transport, is the most frequent porin in E. coli; it was also chosen as the potential receptor of the phage. And the Rz/Rz1 was engaged in the breakup of the host bacterial external membrane. This study aimed to analyze the amino acid of OmpA and Rz/Rz1 of lytic bacteriophage from Surabaya, Indonesia. This study employed a sample of 8 bacteriophages from the previous study. The OmpA analysis method was mass spectrometry. Rz/Rz1 was analyzed using PCR, DNA sequencing, Expasy Translation, and Expasy ProtParam. The result obtained 10% to 29% sequence coverage of OmpA, carrying the ligand-binding site. The Rz/Rz1 gene shares a high percentage of 97.04% to 98.89% identities with the Siphoviridae isolate ctTwQ4, partial genome, and Myoviridae isolate cthRA4, partial genome. The Mann-Whitney statistical tests indicate the significant differences between Alanine, Aspartate, Glycine, Proline, Serine (p=0.011), Asparagine, Cysteine (p=0.009), Isoleucine (p=0.043), Lysine (p=0.034), Methionine (p=0.001), Threonine (p=0.018), and Tryptophan (p=0.007) of OmpA and Rz/Rz1. The conclusion obtained from this study is the fact that OmpA acts as Phage 1, Phage 2, Phage 3, Phage 5, and Phage 6 receptors for its peptide composition comprising the ligand binding site, and Rz/Rz1 participates in host bacteria lysis.