Elsevier

Anaerobe

Volume 69, June 2021, 102363
Anaerobe

Case report
First case of abdominal infection caused by bacteroides fluxus

https://doi.org/10.1016/j.anaerobe.2021.102363Get rights and content

Highlights

  • Bacteroides fluxus has never been associated with human infections until now.

  • This is the first case of abdominal infection caused by this anaerobe in pure culture.

  • Mass spectrometry and molecular techniques are useful in the diagnosis of anaerobes.

  • The antimicrobial susceptibility pattern was similar to other Bacteroides strains.

Abstract

Bacteroides fluxus is a Gram-negative anaerobic bacillus isolated from human faeces in healthy individuals. Until now, this bacterium had not been involved in human diseases. We report the first case of abdominal infection due to this microorganism in an elderly patient. A 76-year-old man with a history of chronic pulmonary obstructive disease presented with dyspnea, orthopnea and cough. The clinical evolution worsened with both a colonic ischemia and further diffuse peritonitis of pancreatic origin. Peritoneal fluid was obtained and the culture yielded B. fluxus in pure culture. Resistance to penicillin, amoxicillin-clavulanate, clindamycin and moxifloxacin was documented. Treatment with meropenem + linezolid was started, but the patient finally died due to a multiorganic failure.

Introduction

Bacteroides spp. are Gram-negative anaerobic bacilli which are predominant members of the human gastrointestinal microbiota [1]. Currently, the genus Bacteroides comprised 127 recognized species (List of Prokaryotic names with Standing in Nomenclature; http://lpsn.dsmz.de); among them, B. fragilis has been both the most frequently isolated and the most relevant species from a clinical point of view. Other species belonging to this genus have been less frequently identified as pathogens. During the last decade, some new species have been identified after isolation from faecal samples of healthy individuals [2]. We recently observed a rare case of abdominal infection due to B. fluxus in a patient with a clinical history of pancreatitis and intestinal ischemia. To our knowledge, this is the first description of this anaerobic microorganism obtained from a clinical sample in pure culture.

Section snippets

Case report

A 76-year-old man was admitted to the Emergency Department of our hospital after 24 hours with increased dyspnea, orthopnea and non-productive cough. His clinical history was remarkable for chronic pulmonary obstructive disease (CPOD) and chronic respiratory insufficiency for more than 10 years. At admission, the physical exam only showed tachypnea (23 bpm) and lung basal hypoventilation. Blood analysis showed increased levels of urea [88 mg/dL, (17–43 mg/dL)], creatinine [1.34 mg/dL, (0.67–1.2

Discussion

Among the anaerobic Gram-negative bacilli, the B. fragilis group, especially B. fragilis subsp fragilis, is most commonly isolated from human infections [6]. Other members of this group frequently recovered include B. ovatus, B. thetaiotaomicron, and B. vulgatus [6]. All these species are part of the normal gastrointestinal microbiota and they are commonly described as pathogens causing most often intraabdominal infections and abscess formation. In addition, when the mucosal barrier becomes

Declaration of competing interest

Authors declare no conflict of interest.

Acknowledgements

Support for this research was provided by the European Union, 3TR (H2020-JTI538, IMI-2), 2018.

VPC was supported by “Programa de Promoción de Empleo Joven e Implantación de la Garantía Juvenil en I + D + I″, MIMECO, Spain.

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