Morphological, biological, and genomic characterization of Klebsiella pneumoniae phage vB_Kpn_ZC2

Abstract

Background Bacteriophages (phages) are one of the most promising alternatives to traditional antibiotic therapies, especially against multidrug-resistant bacteria. Klebsiella pneumoniae is considered to be an opportunistic pathogen that can cause life-threatening infections. Thus, this study aims at the characterization of a novel isolated phage vB_Kpn_ZC2 (ZCKP2, for short). Methods The phage ZCKP2 was isolated from sewage water by using the clinical isolate KP/08 as a host strain. The isolated bacteriophage was purified and amplified, followed by testing of its molecular weight using Pulse-Field Gel Electrophoresis (PFGE), transmission electron microscopy, antibacterial activity against a panel of other Klebsiella pneumoniae hosts, stability studies, and whole genome sequencing. Results Phage ZCKP2 belongs morphologically to siphoviruses as indicated from the Transmission Electron Microscopy microgram. The Pulsed Field Gel Electrophoresis and the phage sequencing estimated the phage genome size of 48.2 kbp. Moreover, the absence of lysogeny-related genes, antibiotic resistance genes, and virulence genes in the annotated genome suggests that phage ZCKP2 is safe for therapeutic use. Genome-based taxonomic analysis indicates that phage ZCKP2 represents a new family that has not been formally rated yet. In addition, phage ZCKP2 preserved high stability at different temperatures and pH values (-20 − 70 °C and pH 4 – 9). For the antibacterial activity, phage ZCKP2 maintained consistent clear zones on KP/08 bacteria along with other hosts, in addition to effective bacterial killing over time at different MOIs (0.1, 1, and 10). Also, the genome annotation predicted antibacterial lytic enzymes. Furthermore, the topology of class II holins was predicted in some putative proteins with dual transmembrane domains that contribute significantly to antibacterial activity. Phage ZCKP2 characterization demonstrates safety and efficiency against multidrug-resistant K. pneumoniae, hence ZCKP2 is a good candidate for further in vivo and phage therapy clinical applications.

Physiochemical characterization of a potential Klebsiella phage MKP-1 and analysis of its application in reducing biofilm formation

“…The killing curve also showed that the lytic activity of phage MKP-1 is MOI-dependent, and the higher MOI (MOI 10) was optimal for the greatest reduction of host cells. These findings are quite similar to the previously reported phages such as Klebsiella phage ZCKP2 ( Fayez et al, 2023 ), vB_KpnS_Kp13 ( Horváth et al, 2020 ) and P545 ( Li et al, 2020 ). The clear plaques produced on the bacterial lawn also ensure its lytic nature, nullifying it being a temperate phage.…”

“…Considering the growth curve of this phage, a high latent period (40 min) of the phage is often an indicator of high burst size ( Abedon et al, 2001 ), confirming its effective use as therapeutics. The large burst size (more than 200 pfu per cell) is comparable to other Klebsiella phages such as phage KP 1801 and ZCKP2 ( Wintachai et al, 2020 ; Fayez et al, 2023 ). However, unlike phage MKP-1, other Siphoviridae Klebsiella phages have been shown to have a latent period of approximately 20 min ( Horváth et al, 2020 ; Fayez et al, 2023 ).…”

The application of bacteriophage ZCEC5 to control multi-drug resistant E. coli in dairy products

“…A slight decrease in stability was observed at pH 12 with no ability to detect phages at pH 2, 3, and 13 (Figure 3). The stability of our isolated phage at different values of pH indicated that the phage can withstand harsh conditions as indicated before [50,75,72,76,77,78] and this is considered an added value since the optimal minimum pH for most cheese manufacturing is in the range of (5.0 -5.3) [79]. Such characteristics enable the use of phage in industrial applications since the stretching properties of cheese, melting, and texture can be influenced by many factors, including cheese composition, Ca content, salt content, protocols of manufacturing, and pH [80].…”

Isolation of Restriction Enzyme from Sewage Samples Derived Bacillus sp.

“…Phages from the collection showed a narrow host range, in most cases affecting different strains of the same bacterial species. Bacteriophages can replicate in two ways once attached to the host: lytically and lysogenically (8,9) . Bacteria can protect themselves against the attack of bacteriophages in various ways.…”