Towards pharmacokinetic boosting of phenoxymethylpenicillin (penicillin-V) using probenecid for the treatment of bacterial infections.

In the face of increasing antimicrobial tolerance and resistance there is a global obligation to optimise oral antimicrobial dosing strategies including narrow spectrum penicillins, such as penicillin-V. We conducted a randomised, crossover study in healthy volunteers to characterise the influence of probenecid on penicillin-V pharmacokinetics and estimate the pharmacodynamics against Streptococcus pneumoniae. Twenty participants took six doses of penicillin-V (250 mg, 500 mg or 750 mg four times daily) with and without probenecid. Total and free concentrations of penicillin-V and probenecid were measured at two timepoints. A pharmacokinetic model was developed, and the probability of target attainment (PTA) calculated. The mean difference (95% CI) between penicillin-V alone and in combination with probenecid for serum total and free penicillin-V concentrations was significantly different at both timepoints (total: 45 min 4.32 (3.20-5.32) mg/L p < 0.001, 180 min 2.2 (1.58-3.25) mg/L p < 0.001; free: 45 min 1.15 (0.88-1.42) mg/L p < 0.001, 180 min 0.5 (0.35-0.76) mg/L p < 0.001). There was no difference between the timepoints in probenecid concentrations. PTA analysis shows probenecid allows a fourfold increase in MIC cover. Addition of probenecid was safe and well tolerated. The data support further research into improved dosing structures for complex outpatient therapy and might also be used to address penicillin supply shortages.

A pilot study investigating severe community-acquired febrile illness through implementation of an innovative microbiological and nucleic acid amplification testing strategy in Timor-Leste (ISIN-MANAS-TL).

Objectives: Acute febrile illness (AFI) causes significant health-seeking, morbidity, and mortality in Southeast Asia. This pilot study aimed to describe presentation, etiology, treatment, and outcomes of patients with AFI at one hospital in Timor-Leste and assessing the feasibility of conducting larger studies in this setting. Methods: Patients attending Hospital Nacional Guido Valadares with tympanic or axillary temperature ≥37.5°C in whom a blood culture was taken as part of routine clinical care were eligible. Participants were followed up daily for 10 days and again after 30 days. Whole blood was analyzed using a real-time quantitative polymerase chain reaction assay detecting dengue virus serotypes 1-4 and other arthropod-borne infections. Results: A total of 82 participants were recruited. Polymerase chain reaction testing was positive for dengue in 14 of 82 (17.1%) participants and blood culture identified a bacterial pathogen in three of 82 (3.7%) participants. Follow-up was completed by 75 of 82 (91.5%) participants. High rates of hospital admission (58 of 82, 70.7%), broad-spectrum antimicrobial treatment (34 of 82, 41.5%), and mortality (9 of 82, 11.0%) were observed. Conclusions: Patients with AFI experience poor clinical outcomes. Prospective observational and interventional studies assessing interventions, such as enhanced diagnostic testing, clinical decision support tools, or antimicrobial stewardship interventions, are required and would be feasible to conduct in this setting.