Beschreibung:
<jats:title>Abstract</jats:title><jats:sec>
<jats:title>Background</jats:title>
<jats:p>Multidrug-resistant <jats:italic>Klebsiella pneumoniae spp. (kp)</jats:italic> are emerging agents of severe infections of the respiratory, urinary tract and wounds that can progress to fatal septicemia. The use of bacteriophages is currently being considered as an effective alternative or adjuvant to antibiotic therapy.</jats:p>
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<jats:title>Results</jats:title>
<jats:p>In this study, we report capsule (K)-typing of 163 carbapenem-resistant <jats:italic>Kp</jats:italic> (CRKP) isolated 2014–2018 at the Military Hospital of Instruction of Tunis (MHT), Tunisia, by partial amplification and sequencing of the <jats:italic>Kp wzi</jats:italic> gene. The most prevalent K-type overall was K64 with 50.3% followed by K17 and K27 (22.7 and 11.0%, respectively). K64 <jats:italic>Kp</jats:italic> strains were most common and associated with increased case/fatality rates, especially at the intensive care unit (ICU). Using a K64 <jats:italic>Kp</jats:italic> strain we isolated and characterized a lytic <jats:italic>Kp</jats:italic> phage, vB_KpP_TUN1 (phage TUN1), from wastewater samples of the ICU at the MHT. TUN1 belongs to the <jats:italic>Autographiviridae</jats:italic> family and specifically digests K64 <jats:italic>Kp</jats:italic> capsules most probably via a depolymerase encoded by <jats:italic>gp47</jats:italic>. Furthermore, we successfully assembled phage TUN1 in a non-replicative host (<jats:italic>E. coli</jats:italic>) raising the possibility of in vitro assembly in the absence of live bacterial hosts. We propose that phage TUN1 is a promising candidate to be used as an adjuvant or an alternative to antibiotic therapy in CRKP infections, facilitating regulatory approval of phage therapy.</jats:p>
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<jats:title>Conclusions</jats:title>
<jats:p>K64, K17 and K27 are the most common <jats:italic>wzi</jats:italic> capsule types in this geographical location in Northern Africa. The lytic phage TUN1 efficiently lyses K64 <jats:italic>Kp</jats:italic> strains associated with increased case/fatality rates at body temperature. Together with its ability to be rescued in a non-replicative host these features enhance the utility of this phage as an antibacterial agent.</jats:p>
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