Antibiotic sensitivity in correlation to the origin of secondary peritonitis: a single center analysis

Comparative Analysis of Demographic and Clinical Findings in Spontaneous, Peritoneal Dialysis-Related, and Secondary Bacterial Peritonitis

Background This study aims to contribute to peritonitis management strategies by comparing the demographic, clinical, and laboratory characteristics of patients diagnosed with spontaneous bacterial peritonitis (SBP), peritoneal dialysis-related peritonitis (PDrP), and secondary peritonitis. Methods This study included 86 patients diagnosed with peritonitis between 2016 and 2022. Patients were categorized and compared as SBP, PDrP, and secondary peritonitis. Results SBP was diagnosed in 36% of patients, secondary peritonitis in 36% and PDrP in 28%. The mean age of patients with PDrP is 43.71 ± 14.74, which is significantly lower compared to those with SBP and secondary peritonitis (p<0.001). Patients with hypertension (HT), chronic kidney disease (CKD), and those undergoing dialysis most commonly have PDrP whereas those without HT, without CKD, and not undergoing dialysis are most often diagnosed with secondary peritonitis (p=0.002, p<0.001, p<0.001). In peritoneal fluid cultures, the growth of Gram-positive bacteria was most commonly identified in patients with PDrP, while the growth of Gram-negative bacteria was most frequently seen in patients with secondary peritonitis (p=0.018). CRP levels and sedimentation rates were found to be higher in patients with secondary peritonitis (p<0.001, p=0.003). Conclusion The distinct characteristics observed across different types of peritonitis underscore the importance of tailored approaches to diagnosis and treatment. Parameters such as CRP levels, sedimentation rates, and patient age could serve as valuable indicators in discerning between various types of peritonitis. When selecting empirical antibiotic therapy, it's crucial to consider coverage for Gram-positive pathogens in cases of PDrP and Gram-negative pathogens in secondary peritonitis.

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.

Bacterial and Antibiotic Sensitivity Pattern in Secondary Peritonitis

Background

Peritonitis is inflammation of the peritoneum usually as a result of a localized or generalized infection. Secondary peritonitis which is the most common type follows an infective process in a visceral organ. The role of peritoneal cultures and use of antibiotics effective against culture results remain controversial.

Objectives

This study was conducted to determine the bacterial and antibiotic sensitivity pattern in patients with secondary peritonitis. It also compared the use of empirical antibiotics and culture-sensitive antibiotics with outcomes of patients with secondary peritonitis.

Materials and Methods

A prospective randomized clinical study was conducted. Five millilitres of peritoneal fluid was sampled intra-operatively, and microscopy, culture, and sensitivity testing was performed in patients with secondary peritonitis. The patients, randomized into two groups, had antibiotics administered for 7 days. The first group had empirical antibiotics throughout (Ceftriaxone + Metronidazole), whereas the second group had empirical antibiotics (Ceftriaxone + Metronidazole) for the first 2 days and antibiotics according to the sensitivity report for the remaining 5 days. The post-hoc analysis was also done on a third group, who, even though were randomized to either groups, had no growth on culture of peritoneal fluid.

Results

The commonest pathogens identified from the peritoneal culture of the participants were Escherichia coli, Klebsiella pneumonia, Anaerococcus group, and Bacteroides fragilis. Complications including mortality were significantly higher in those who received empirical antibiotics than those who received culture-sensitive antibiotics.

Conclusion

The outcome of antibiotics administration in patients with secondary peritonitis with a positive culture was better in those who received culture-sensitive antibiotics than those who received empirical antibiotics.

Development and validation of an LC-ESI-QTOF-MS method to measure cefepime in the plasma and peritoneal fluid of rats using microdialysis: application in a pilot pharmacokinetic study

Cefepime (CEF) is a cephalosporin and can be administered in secondary peritonitis together with metronidazole to treat sepsis. This study aimed to develop and validate a method of LC-ESI-QTOF-MS for the quantification of cefepime in the plasma and peritoneal microdialysate of healthy Wistar rats. Chromatographic separation was performed using a CLC-ODS C₁₈ column (250 mm x 4.6 mm), a C₁₈ pre-column (4 mm, 5 μm) and isocratic elution. Gallic acid was used as the internal standard (IS). The mobile phase consisted of (A) ultrapure water (pH adjusted to 3.5) and (B) acetonitrile (80:20, v/v) at 0.8 mL/min. Quantification was performed using a mass spectrometer with electrospray ionization in positive mode to monitor ions with m/z 481.1322 (CEF) and m/z 171.0288 (IS). The method was validated for selectivity, precision, accuracy, linearity, stability, lower limit of quantification, carryover, recovery, and matrix effect. Calibration was done in the range of 1-40 μg/mL and 1-100 μg/mL for the peritoneal microdialysate and plasma, respectively. Plasma extraction recovery ranged from 93.9% to 99.9%. The technique was validated and successfully applied in a pilot pharmacokinetic study for estimating the free concentration of CEF in the peritoneal microdialysate of rats for the first time.