Michalik-Provasek, J. | Search bioRxiv

bioRxiv2026

Genomic Characterization of 30 Lytic Klebsiella pneumoniae Bacteriophages

The spread and rise of antimicrobial resistance poses a risk to public health due to limited effective treatment options. Alternative antimicrobials that are effective against gram-negative multi-drug resistant pathogens. The increasing rate of carbapenem resistance observed in Klebsiella pneumoniae, indicates the need for alternative antimicrobial options. Bacteriophages that target Klebsiella pneumoniae are promising alternative antimicrobial option, with successful treatments being reported. Here we characterized 30 lytic bacteriophages from various environmental sources and tested their effectiveness against nine clinically relevant carbapenem-resistant K. pneumoniae isolates. These phages were characterized through genomic sequencing, bioinformatic analysis, virulence in liquid medium, and host range on different mediums. Bioinformatic analysis revealed a diverse collection of phages that span 9 ICTV recognized families and 13 genera with genome sizes ranging from 39-349 kbp. The phages were able to inhibit bacterial growth, and no virulence or antibiotic resistance genes were detected within the phage genomes. Host range testing demonstrated phages with broad host range have varying infectivity when plated on different common growth mediums. This study includes candidate phages for further potential development as potential antimicrobial agents against CR-KP, and the complexity in understanding phage-host dynamics of non-capsule phages that target against K. pneumoniae.

microbiology↗

bioRxiv2024

Bacteriophage Treatment against Carbapenem-resistant Klebsiella pneumoniae (KPC) in a Neutropenic Murine Model of Gastrointestinal Translocation and Renal Infection

BackgroundCarbapenemase producing Klebsiella pneumoniae (KPC) are globally emerging pathogens which that cause life-threatening infections. Novel treatment alternatives are urgently needed. MethodsWe therefore investigated the effectiveness of three novel bacteriophages (Spivey, Pharr and Soft) in a neutropenic murine model of KPC gastrointestinal colonization, translocation, and disseminated infection. Bacteriophage efficacy was determined by residual bacterial burden of KPC in kidneys. Parallel studies were conducted of bacteriophage pharmacokinetics and resistance.. ResultsTreatment of mice with 5x109 PFU of phage cocktail via intraperitoneal injection was effective in significantly reducing renal KPC burden by 102 CFU (p<0.01) when administered every 24 hours and 103 CFU (p<0.01) every 12 hours. Moreover, a combination of bacteriophage and ceftazidime-avibactam produced a synergistic effect, resulting in a 105 reduction in bacterial burden in caecum and kidney (p<0.001 in both tissues). Prophylactic administration of bacteriophages via oral gavage did not prevent KPC translocation to the kidneys. Bacteriophage decay determined by linear regression of the ln of mean concentrations demonstrated R2 values in plasma of 0.941, kidney 0.976, and caecum 0.918, with half-lives of 2.5h < t1/2 < 3.5 h. Furthermore, a phage-resistant mutant displayed increased sensitivity to serum killing in vitro, but did not show significant defects in renal infection in vivo. ConclusionsA combination of bacteriophages demonstrated significant efficacy alone and synergy with ceftazidime/avibactam in treatment of experimental disseminated KPC infection in neutropenic mice.

microbiology↗