Bacteriophage in combination with ciprofloxacin againstPseudomonas aeruginosainfections in diabetic foot ulcer patients

Abstract

BackgroundIn diabetic foot ulcer (DFU) patients,Pseudomonas aeruginosa(P. aeruginosa) infections are linked to poor wound healing. The ineffectiveness of antibiotics against these infections promotes the emergence of multidrug-resistant (MDR) strains. Bacteriophage (phage) therapy has recently gained popularity as an alternative to antibiotics.MethodologyBacterial and viral swabs and tissue were obtained from DFU infections (DFI). Bacteria were cultured followed by MALDI-TOF MS for identification. 16S rRNA long-read sequencing was used to identify the microbiota. Bacteriophages were isolated and underwent transmission electron microscopy, genomic sequencing, and stability testing. The antimicrobial activity of phages alone and in combination with ciprofloxacin againstP. aeruginosaplanktonic cells and biofilm grownin vitroand inex vivotissue was tested by measuring the optical density (OD), crystal violet assays and live/dead staining with visualisation using confocal scanning laser microscopy respectively.ResultsA total of 34 DFI patients were recruited from which microbiota were analysed for 25 patients.P. aeruginosawas the most prevalent pathogen cultured and was one of the top 6 most prevalent and abundant species in the microbiota analysis. Phage APTC-PA18 was isolated from DFIs, belonged to themyoviridaefamily and was strictly lytic. PA18 was stable between 4 and 70 degrees Celsius and between pH 3 and 11. Seven of eightP. aeruginosaclinical isolates were sensitive to APTC-PA18, and when APTC-PA18 was combined with ciprofloxacin against planktonic and biofilm ofP. aeruginosa, synergistic effects were observedin vitroand in DFI tissue samples.ConclusionPhage APTC-PA18, when combined with ciprofloxacin, has the ability to killP. aeruginosaclinical isolates bothin vitroandex vivoand is a promising treatment option forP. aeruginosainfections in DFUs.