Isolation, Characterization, Genome Analysis and Host Resistance Development of Two Novel <i>Lastavirus</i> Phages Active against Pandrug-Resistant <i>Klebsiella pneumoniae</i>
Mina Obradović,
Milka Malešević,
Mariagrazia Di Luca,
Dušan Kekić,
Ina Gajić,
Olivia McAuliffe,
Horst Neve,
Nemanja Stanisavljević,
Goran Vukotić,
Milan Kojić
Affiliations
Mina Obradović
Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000 Belgrade, Serbia
Milka Malešević
Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000 Belgrade, Serbia
Mariagrazia Di Luca
Department of Biology, University of Pisa, 56127 Pisa, Italy
Dušan Kekić
Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia
Ina Gajić
Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia
Olivia McAuliffe
Department of Food Biosciences, Teagasc Food Research Centre, P61 C996 Fermoy, Ireland
Horst Neve
Department of Microbiology and Biotechnology, Max Rubner-Institut, 24103 Kiel, Germany
Nemanja Stanisavljević
Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000 Belgrade, Serbia
Goran Vukotić
Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000 Belgrade, Serbia
Milan Kojić
Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000 Belgrade, Serbia
Klebsiella pneumoniae is a global health threat and bacteriophages are a potential solution in combating pandrug-resistant K. pneumoniae infections. Two lytic phages, LASTA and SJM3, active against several pandrug-resistant, nosocomial strains of K. pneumoniae were isolated and characterized. Their host range is narrow and latent period is particularly long; however, their lysogenic nature was refuted using both bioinformatic and experimental approaches. Genome sequence analysis clustered them with only two other phages into the new genus Lastavirus. Genomes of LASTA and SJM3 differ in only 13 base pairs, mainly located in tail fiber genes. Individual phages, as well as their cocktail, demonstrated significant bacterial reduction capacity in a time-dependent manner, yielding up to 4 log reduction against planktonic, and up to 2.59 log on biofilm-embedded, cells. Bacteria emerging from the contact with the phages developed resistance and achieved numbers comparable to the growth control after 24 h. The resistance to the phage seems to be of a transient nature and varies significantly between the two phages, as resistance to LASTA remained constant while resensitization to SJM3 was more prominent. Albeit with very few differences, SJM3 performed better than LASTA overall; however, more investigation is needed in order to consider them for therapeutic application.
