Effect of different drugs and drug combinations on killing stationary phase and biofilms recovered cells of Bartonella henselae in vitro.
Level 5 - mechanism / opinion, no new human data
In vitro laboratory study with no human or animal subjects (CEBM Level 5).
PubMed 32276590 · doi:10.1186/s12866-020-01777-9
What was done
The authors evaluated 14 single antibiotics (all tested at 5 μg/ml) and 25 antibiotic combinations in vitro against stationary phase and biofilm-recovered cells of Bartonella henselae. Bacterial survival was assessed after 1 day of drug exposure for stationary phase cells and after 6 days for biofilm-derived bacteria.
What was found
Ciprofloxacin, gentamicin, and nitrofurantoin were the most active monotherapies against stationary phase B. henselae, whereas clofazimine and miconazole showed poor activity. Four combinations—azithromycin/ciprofloxacin, azithromycin/methylene blue, rifampin/ciprofloxacin, and rifampin/methylene blue—reduced stationary-phase viable counts to no detectable colony-forming units (CFUs) within 1 day. Against biofilm-derived bacteria, methylene blue and rifampin were the most active single agents at 6 days, and the same four drug combinations completely eradicated biofilm cells after 6 days. Quantitative CFU numbers and confidence intervals were not reported in the abstract.
Why it matters
Persistent B. henselae infections can be refractory to standard clinical regimens; identifying regimens effective against non-replicating and biofilm phenotypes highlights candidate combination therapies for future preclinical evaluation.
Limits
Findings are entirely limited to in vitro cell cultures and do not account for in vivo pharmacokinetics, tissue penetration, safety, or host immune interactions. All drugs were evaluated at a single fixed concentration (5 μg/ml), and precise quantitative survival data or concentration-response curves were not reported in the abstract.
Cited by
- supports A Johns Hopkins study showed that a 6-day combination of rifampin, azithromycin, and methylene blue eradicated Bartonella in cell culture.