BRIEF COMMUNICATIONS: A quantity survey of intravenous administration of metronidazole in its different forms in a tertiary teaching hospital

Improving metronidazole prescription practices in surgical patients: a full cycle audit

INTRODUCTION

Metronidazole is commonly prescribed for intra-abdominal infections. Oral metronidazole has high bioavailability (>95%) and intravenous metronidazole should be reserved for patients not suitable for oral preparations.

METHODS AND MATERIALS

This full cycle audit evaluated the type of metronidazole preparation prescribed in adult emergency surgical patients requiring first-line empirical antimicrobial therapy for intra-abdominal infections. The criterion for audit was the proportion of patients who were prescribed intravenous metronidazole when the oral route was available. The first cycle included all consecutive eligible patients between 20 April and 14 May 2020. After an intervention phase educating prescribers about the similar pharmacokinetic properties of oral and intravenous metronidazole, clinical practice was reaudited between 22 June and 16 July 2020. Data were collected by case note and drug chart review.

RESULTS

A total of 54 patients were included in the first audit cycle. Of these, 11 (20.4%) were prescribed oral metronidazole and 43 (79.6%) were prescribed intravenous metronidazole. In the majority of cases (35/43, 81.4%), intravenous metronidazole was prescribed in the absence of clear contraindications to the oral preparation. Of the 61 patients included in the reaudit cycle, 23 (37.7%) were prescribed oral metronidazole and 38 (62.3%) were prescribed intravenous metronidazole. The proportion of patients prescribed intravenous metronidazole despite being suitable for oral preparation decreased from 81.4% in the first cycle to 34.2% (13/38) in the reaudit cycle (risk ratio 0.42, 95% CI: 0.26 to 0.67, p<0.0001). Prescribing oral metronidazole when suitable saved up to £10.53/day per patient.

CONCLUSION

This full cycle audit led to a significant improvement in the use of oral metronidazole in suitable patients, as well as a considerable reduction in healthcare costs.

Drug resistance in Giardia: Mechanisms and alternative treatments for Giardiasis

The use of chemotherapeutic drugs is the main resource against clinical giardiasis due to the lack of approved vaccines. Resistance of G. duodenalis to the most used drugs to treat giardiasis, metronidazole and albendazole, is a clinical issue of growing concern and yet unknown impact, respectively. In the search of new drugs, the completion of the Giardia genome project and the use of biochemical, molecular and bioinformatics tools allowed the identification of ligands/inhibitors for about one tenth of ≈150 potential drug targets in this parasite. Further, the synthesis of second generation nitroimidazoles and benzimidazoles along with high-throughput technologies have allowed not only to define overall mechanisms of resistance to metronidazole but to screen libraries of repurposed drugs and new pharmacophores, thereby increasing the known arsenal of anti-giardial compounds to some hundreds, with most demonstrating activity against metronidazole or albendazole-resistant Giardia. In particular, cysteine-modifying agents which include omeprazole, disulfiram, allicin and auranofin outstand due to their pleiotropic activity based on the extensive repertoire of thiol-containing proteins and the microaerophilic metabolism of this parasite. Other promising agents derived from higher organisms including phytochemicals, lactoferrin and propolis as well as probiotic bacteria/fungi have also demonstrated significant potential for therapeutic and prophylactic purposes in giardiasis. In this context the present chapter offers a comprehensive review of the current knowledge, including commonly prescribed drugs, causes of therapeutic failures, drug resistance mechanisms, strategies for the discovery of new agents and alternative drug therapies.

The novel use of oral antibiotic monotherapy in prosthetic valve endocarditis caused by Finegoldia magna: a case study

Background

Finegoldia magna, a Gram-positive anaerobic coccus, is part of the human normal microbiota as a commensal of mucocutaneous surfaces. However, it remains an uncommon pathogen in infective endocarditis, with only eight clinical cases previously reported in the literature.

Currently, infective endocarditis is routinely treated with prolonged intravenous antibiotic therapy. However, recent research has found that switching patients to oral antibiotics is non-inferior to prolonged parenteral antibiotic treatment, challenging the current guidelines for the treatment of infective endocarditis.

Case presentation

This case report focuses on a 52-year-old gentleman, who presented with initially culture-negative infective endocarditis following bioprosthetic aortic valve replacement. Blood cultures later grew Finegoldia magna. Following initial intravenous antibiotic therapy and re-do surgical replacement of the prosthetic aortic valve, the patient was successfully switched to oral antibiotic monotherapy, an unusual strategy in the treatment of infective endocarditis inspired by the recent publication of the POET trial. He made excellent progress on an eight-week course of oral antibiotics and was successfully discharged from surgical follow-up.

Conclusions

This case is the 9th reported case of Finegoldia magna infective endocarditis in the literature. Our case also raises the possibility of a more patient-friendly and cost-effective means of providing long-term antibiotic therapy in suitable patients with prosthetic valve endocarditis and suggests that the principles highlighted in the POET trial can also be applicable to post-operative patients after cardiac surgery.