The plasma pharmacokinetics of fosfomycin and metronidazole after intraperitoneal administration in patients undergoing appendectomy for uncomplicated appendicitis

Parenteral Fosfomycin in Gastrointestinal Surgery: A Systematic Review

BACKGROUND

To investigate if perioperative parenteral administration of fosfomycin given before or during gastrointestinal surgery could protect against postoperative infectious complications and characterise the administration of fosfomycin and its harms.

METHODS

This systematic review included original studies on gastrointestinal surgery where parental administration of fosfomycin was given before or during surgery to≥5 patients. We searched three databases on March 24 2023 and registered the protocol before data extraction (CRD42020201268). Risk of bias was assessed with Cochrane Handbook risk of bias assessment tool or the Newcastle-Ottawa Scale. A narrative description was undertaken. For infectious complications, results from emergency and elective surgery were presented separately.

RESULTS

We included 15 unique studies, reporting on 1,029 patients that received fosfomycin before or during gastrointestinal surgery. Almost half of the studies were conducted in the 1980s to early 1990s, and typically a dose of 4 g fosfomycin was given before surgery co-administered with metronidazole and often repeated postoperatively. The risk of bias across studies was moderate to high. The rates of infectious complications were low after fosfomycin; the surgical site infection rate was 0-1% in emergency surgery and 0-10% in elective surgery. If reported, harms were few and mild and typically related to the gastrointestinal system.

CONCLUSION

There were few postoperative infectious complications after perioperative parenteral administration of one or more doses of 4 g fosfomycin supplemented with metronidazole in various gastrointestinal procedures. Fosfomycin was associated with few and mild harms.

Fast determination of free metronidazole in rat plasma and peritoneal fluid using HPLC-UV method

Peritonitis refers to the inflammatory reaction of the peritoneum to aggression. In addition, it contributes significantly to sepsis. The presence of free concentrations of antimicrobials above the minimum inhibitory concentration at the site of infection is critical to therapeutic response. Metronidazole (MTZ) is an antimicrobial used to treat peritonitis because of its effectiveness against anaerobic microorganisms. This study investigates free MTZ concentrations in peritoneal microdialysate in Wistar rats. A C₁₈ column (150 × 4.0 mm, 5 μm) was used for the analysis conducted at 40°C under isocratic conditions. The mobile phase consisted of acetonitrile and an aqueous solution of 50-mM monobasic phosphate buffer and 0.1% triethylamine, with pH 3.0 (10:90, v/v). MTZ calibration was linear in the range of 0.5-30.0 μg/ml. The intra- and inter-day precision was satisfactory with relative standard deviation ≤5.67%. The accuracy ranged from 90.64 to 103.77%, and the lower limit of quantification was 0.5 μg/ml. The developed method was successfully applied in a pilot pharmacokinetic study after MTZ administration (30 mg/kg, intravenously) in rats. The main advantage of the employed method is that it does not require sample processing and protein removal steps. This is the first study to be conducted using MTZ in rats.

Fosfomycin, Applying Known Methods and Remedies to A New Era

The exponential increase in the numbers of isolates of Carbapenem-Resistant Enterobacteriaceae (CRE) creates the need for using novel therapeutic approaches to save the lives of patients. Fosfomycin has long been considered a rational option for the treatment of CRE to be used as part of a combined therapy scheme. However, the assessment of fosfomycin susceptibility in the laboratory presents a great challenge due to the discrepancies found between different methodologies. Thus, our goal was to evaluate fosfomycin susceptibility in a group of 150 Enterobacteriaceae bacterial isolates using agar dilution as the gold standard technique to compare the results with those obtained by disk diffusion. We found a fosfomycin susceptibility of 79.3% in general terms. By comparing both methodologies, we reported a categorical agreement of 96% without Very Major Errors (VMEs) or Major Errors (MEs) and 4% of minor Errors (mEs). Our results suggest that fosfomycin could provide a rational alternative treatment for those patients that are infected by a Multidrug-Resistant (MDR) microorganism that is currently untreatable and that the disk diffusion and classical agar dilution techniques are adequate to assess the resistance profile of CRE to fosfomycin.

Shorter Total Length of Stay After Intraperitoneal Fosfomycin, Metronidazole, and Molgramostim for Complicated Appendicitis: A Pivotal Quasi-Randomized Controlled Trial

Background: We aimed to investigate the difference in the total length of hospital stay (LOS) after intraperitoneal vs. intravenous antibiotic treatment in patients with complicated appendicitis.

Methods: We conducted a quasi-randomized prospective clinical trial. The intervention group received 4 g fosfomycin, 1 g metronidazole, and 50 μg recombinant human granulocyte-macrophage colony-stimulating factor intraperitoneally, which was left in the abdominal cavity, immediately after laparoscopic appendectomy. Postoperatively, this group received antibiotics orally. The control group received intravenous antibiotics both during surgery and postoperatively. We primarily evaluated total LOS within 30 days. Furthermore, we evaluated harms and adverse events, Gastrointestinal Quality of Life Index, postoperative complications, and convalescence. Participants were followed for 30 days postoperatively.

Results: A total of 12 participants concluded the trial. The total LOS was significantly shorter in the intervention group (six participants, median 13 h; range 2–21 h) than in the control group (six participants, median 84 h; range 67–169 h), p = 0.017. Comparable harms and Gastrointestinal Quality of Life Index scores were found in the two groups. The time to return to normal activities was median 6 and 10 days for the intervention and the control group, respectively. There were no serious adverse events related to the trial nor any complications in the intervention group. In the control group, two patients developed intraabdominal abscesses.

Conclusions: The intervention group had a significantly shorter total LOS. The study was not powered to assess differences in complications, but the results indicate that the intervention seems to be a safe regimen, which can be investigated further to treat patients with complicated appendicitis.

Identifiers: EudraCT no. 2017-004753-16.

ClinicalTrials:https://clinicaltrials.gov/ct2/show/NCT03435900?term=NCT03435900&draw=2&rank=1">draw=2&rank=1.