Background: Members of the genus Klebsiella are among the leading microbial pathogens associated with nosocomial infection. The increased incidence of antimicrobial resistance in these species has propelled the need for alternate/combination therapeutic regimens to aid clinical treatment, including bacteriophage therapy. Bacteriophages are considered very safe and effective in treating bacterial infections. In this study, we characterize eight lytic bacteriophages that were previously isolated by our team against carbapenem-resistant Klebsiella pneumoniae. Methods: The one-step-growth curves, stability and lytic ability of eight bacteriophages were characterized. Restriction fragment length polymorphism (RFLP), random amplification of polymorphic DNA (RAPD) typing analysis and protein profiling were used to characterize the microbes at the molecular level. Phylogenetic trees of four important proteins were constructed for the two selected bacteriophages. Results and conclusions: All eight bacteriophages showed high efficiency for reducing bacterial concentration with high stability under different physical and chemical conditions. We found four major protein bands out of at least ten 15–190 KDa bands that were clearly separated by SDS-PAGE, which were assumed to be the major head and tail proteins. The genomes were found to be dsDNA, with sizes of approximately 36–87 Kb. All bacteriophages reduced the optical density of the planktonic K. pneumoniae abruptly, indicating great potential to reduce K. pneumoniae infection. In this study, we have found that tail fiber protein can further distinguished closely related bacteriophages. The characterised bacteriophages showed promising potential as candidates against carbapenem-resistant Klebsiella pneumoniae via bacteriophage therapy.

In our previous study, we isolated eight bacterial endophytes with positive antimicrobial activity out of 82 isolates from five different places in Pulau Langkawi. The antimicrobial activity of the endophytes secondary metabolite although moderate, was further explored for the prospect to be enhanced by incorporating to silver nitrates. Only two isolates were able to synthesise silver nanoparticles namely Bacillus subtilis (B7b) and Pseudomonas resinovorans (B2c) within 72 hours of incubation at room temperature via extracellular method. Antimicrobial assay against Staphylococcus aureus, methicilin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermis, Escherichia coli and Pseudomonas aeruginosa was performed. Synthesised silver nanoparticles (AgNPs) showed excellent inhibitory effect against both Gram positive and Gram negative bacteria but secondary metabolites without AgNPs showed positive activity only against Gram positive bacteria. The results suggested that incorporation of AgNPs was able to enhance antimicrobial activity of secondary metabolites of B7b and B2c against test bacteria. � 2019, Malaysian Society of Applied Biology. All rights reserved.

Objective: Aim: Klebsiella pneumonia has emerged as an increasingly important cause of community-acquired nosocomial infections and many of these strains are highly virulent and exhibit a strong propensity to spread. Infections cause by K. pneumonia produces carbapen¬emase (KPC) enzyme and can be difficult to treat since only a few antibiotics are effective against them. Bacteriophage targeting this strain can be an alternative treatment. Characterisation of bacteriophage is utmost important in assisting the application of bacteriophage in phage therapy. Patients and methods: Materials and methods: In the present study, the lytic bacteriophage, k3w7, isolated by the host Klebsiella pneumoniae kP2 was characterised using transmission electron microscope (TEM), plaque assay, and restriction digestive enzyme to investigate mor¬phology, host spectrum, bacteriophage life cycle and stability accordingly. Results: Results and conclusions: As shown by TEM, k3w7 was observed to have the characteristic of icosahedral heads 100 nm and contractile sheaths 120 nm suggesting it belongs to the family of myoviridae.The Investigation has done on the phage growth cycle showed a short latent period of 20 min and a burst size of approximately 220 plaque forming units per infected cell. Stability test showed the phage was stable over a wide range of pH and temperatures. According to restriction analysis, k3w7 had 50 -kb double-stranded DNA genome as well as the heterogeneous nature of genetic material. These findings suggest that K3W7 has a potential use in therapy against infections caused by K. pneumonia produces carbapenemase.

Phage therapy is the therapeutic use of bacteriophages to treat highly drug resistant bacterial infections. Klebsiella pneumonia (KP) has emerged as an increasingly important cause of community-acquired nosocomial infections and many of these strains are highly virulent with multidrug resistance (MDR) ability and exhibit a strong propensity to spread making infection cause by it difficult to treat. Treatment utilizing bacteriophage specific to KP (KP phage) can be used as an alternative counter measure. Characterization of bacteriophage is utmost important in assisting the application of bacteriophage in phage therapy. In the present study, samples from sewage water and cockles were screened for KP phage. Enrichment detection methods followed by isolation of phage by double agar layers method was done using 9 strains of MDR-KP as host system. KP phages were characterized on the basis of plaque morphology, host range and transmission electron microscope (TEM). A total of 58 lytic KP phages were isolated from sewage (42) and cockle (16). Investigation done on host range showed that 52 were KP phage and 6 have broad host range. Further identification by transmission electron microscopy (TEM) was done to 10 selected phages that showed potent lytic activity against MDR-KP. Image from TEM show selected phages were from subfamily caudovirales (7) with icosahedral head and pentagonal structure with short non-contractile tail suggesting it belongs to the family of Podoviridae. Two phages belonged to the family Myoviridae with isometric head and contractile tail and one from the family Siphoviridae with icosahedral and a non-contractile tail. Therefore, this study has partially characterized and revealed 10 potential lytic bacteriophages as therapeutic agent against MDR-KP which mostly resembles Podoviridae family.