Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2023.10.03.560795

Bacteriophage in combination with ciprofloxacin against Pseudomonas aeruginosa infections in diabetic foot ulcer patients

Liu, S.·Goonetilleke, S.·Hon, K.·Burdon, I.·Bouras, G.·Mcmillan, N.·Psaltis, A.·Wormald, P.·Fitridge, R.·Vreugde, S.
View original source ↗Export metadata ↓

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 against P. aeruginosa planktonic cells and biofilm grown in vitro and in ex vivo tissue 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. aeruginosa was 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 the myoviridae family and was strictly lytic. PA18 was stable between 4 and 70 degrees Celsius and between pH 3 and 11. Seven of eight P. aeruginosa clinical isolates were sensitive to APTC-PA18, and when APTC-PA18 was combined with ciprofloxacin against planktonic and biofilm of P. aeruginosa, synergistic effects were observed in vitro and in DFI tissue samples. ConclusionPhage APTC-PA18, when combined with ciprofloxacin, has the ability to kill P. aeruginosa clinical isolates both in vitro and ex vivo and is a promising treatment option for P. aeruginosa infections in DFUs.

Explore related subjects

microbiologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Liu, S., Goonetilleke, S., Hon, K., Burdon, I., Bouras, G., Mcmillan, N., Psaltis, A., Wormald, P., Fitridge, R., Vreugde, S.. 2023-10-04. Bacteriophage in combination with ciprofloxacin against Pseudomonas aeruginosa infections in diabetic foot ulcer patients. https://doi.org/10.1101/2023.10.03.560795

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Extreme temperature exposure has negative demographic consequences for Sulfolobus acidocaldarius

Microorganisms inhabiting geothermal springs and volcanic systems experience fluctuating temperatures that can periodically exceed their upper thermal limits, but the demographic consequences of such exposure remain poorly understood. Here, we investigated demographic responses of the thermophilic archaeon Sulfolobus acidocaldarius to an extreme temperature (94.1{degrees}C) under two regimes: sustained exposure varying in duration, and episodic exposure interspersed with recovery at a permissive temperature (75{degrees}C). Under sustained exposure, populations showed no detectable loss of viability after 15 min but declined thereafter, decreasing by approximately five orders of magnitude after 120 min. Under episodic exposure, populations remained viable across nine exposure-recovery cycles but declined in density with successive cycles. Similar responses were observed for three strains, including a DNA mismatch repair knockout ({Delta}nucS), indicating that mismatch repair deficiency did not affect viability or recovery. Together, these results demonstrate that S. acidocaldarius can withstand brief and repeated exposure to near-boiling temperatures, with mortality determined primarily by cumulative exposure duration rather than a fixed thermal threshold.

microbiology↗
bioRxiv2026

Bacteriophage and Antibiotic Resistance Are Positively Associated across a Phylogenetically Diverse Set of Clinical Pseudomonas aeruginosa Isolates

Co-administration of phages and antibiotics has been proposed as a therapeutic approach against antibiotic-resistant bacteria. The relationship, however, between antibiotic resistance and phage resistance in clinical isolates is unclear. Here, we examine associations between phage and antibiotic resistance profiles across a panel of Pseudomonas aeruginosa clinical isolates from the Centers for Disease Control (CDC) and Food and Drug Administration (FDA) Antimicrobial Resistance Isolate (ARI) Bank comprising 55 clinical strains with full genome sequences and antibiotic susceptibility testing (AST) data for 11 clinically relevant antibiotics. As phages in this study, we use three well-characterized, morphologically distinct phages, OMKO1, Luz19, and PAML31-1. We screen for phage resistance using a growth suppression assay, then conduct statistical analysis against antibiotic MIC (Minimum Inhibitory Concentration) data provided by the CDC to define association patterns across this dataset. We find multiple significant susceptibility correlations between pairs of antibiotics and phages, and a positive overall association between average phage resistance and antibiotic resistance across the 55 strains, even controlling for phylogenetic associations (=0.358, p<0.005). We conclude that phage and antibiotic resistance are positively associated across this clinical isolate collection, suggesting that the two resistance phenotypes are not independent in P. aeruginosa. These findings have implications for the development of phage-antibiotic cocktails.

microbiology↗
bioRxiv2026

The Estuary Effect: Variations in Temperature and Salinity Alter msh Promoter Activity in Vibrio cholerae

Vibrio cholerae, the facultative pathogen underlying cholera, naturally inhabits warm aquatic estuaries. Environmental persistence is enhanced by the ability of V. cholerae to colonize host reservoirs and form multicellular biofilms, causing seasonally endemic outbreaks in many tropical regions. Most toxigenic strains utilize the type IVa mannose-sensitive hemagglutinin (MSHA) pilus for host reservoir colonization and biofilm formation. Temperature and salinity can alter V. cholerae biofilm formation, yet their impact on MSHA production specifically remains largely unknown. Here, we utilized transcriptional reporters of predicted msh promoters (msh-P1/msh-P2/msh-P3) and functional assays, to determine temperature and salinity impacts on msh expression and pilus biogenesis. Under standard laboratory conditions (30{degrees}C, 1% NaCl) only msh-P1/P2 are active and inversely-coordinated with one another. Both msh-P1/P2 activity were elevated by high temperature (37{degrees}C) and low salinity (0.25%/0.5% NaCl), and reduced by low temperature (20{degrees}C/25{degrees}C) and high salinity (2%/3% NaCl). Temperature-mediated alterations in promoter activity were not immediately reflected in changes to cell-surface MSHA levels, whereas high salinity led to decreased MSHA production. Combining high temperature (37{degrees}C) and high salinity (2%/3% NaCl), attenuated the salinity-mediated reduction of msh-P1/P2 activity. Biofilm biomass levels were only substantially heightened at 25{degrees}C and 20{degrees}C, likely a result of no temperature-dependent changes in cell-surface MSHA, and additional temperature-controlled biofilm regulation previously described. We also found msh-P1/P2 promoter activity and MSHA production varies widely across toxigenic O1 and O139 serogroups despite complete sequence homology. These results shed new light on how key signals regulate MSHA pilus production to support V. cholerae persistence in aquatic environments.

microbiology↗