The first case report: diagnosis and management of necrotizing fusobacterium lung abscess via BALF next-generation sequencing

BACKGROUND

Fusobacterium necrophorum (F. necrophorum)-induced necrotizing pneumonia is a rare but severe pulmonary infection. Insufficient microbiological detection methods can lead to diagnostic difficulties.

METHODS

We report a case of F. necrophorum lung abscess diagnosed by next-generation sequencing (NGS) of bronchoalveolar lavage fluid (BALF).

RESULTS

BALF-NGS detected F. necrophorum, guiding subsequent targeted antibiotic therapy. With active drainage and metronidazole treatment, the patient's condition was effectively treated.

CONCLUSION

BALF-NGS is a valuable tool for the rapid diagnosis of infections caused by difficult-to-culture bacteria. It played a decisive role in the early identification of F. necrophorum, enabling timely and targeted antibiotic intervention. Early diagnosis and appropriate treatment are crucial for the management of F. necrophorum pneumonia.

Atypical presentation of Lemierre syndrome in a young healthy man with acute jaundice

This report presents a case of Lemierre syndrome caused by Fusobacterium necrophorum in a healthy young adult who presented atypically with shortness of breath and jaundice but no clinical or diagnostic evidence of thrombophlebitis. Due to this unusual presentation with jaundice, diagnosis was challenging and delayed. However, the patient was successfully initiated on a prolonged course of intravenous antibiotics; he required a period in the intensive care unit and was discharged without significant complications. This report aims to raise awareness of the diagnosis and treatment of this rare condition and to highlight both common and unusual presentations of the syndrome.

Characterization of Fusobacterium isolates from the respiratory tract of white-tailed deer (Odocoileus virginianus)

A total of 23 clinical isolates of Fusobacterium spp. were recovered at necropsy over a 2-year period from the respiratory tract of white-tailed deer ( Odocoileus virginianus). Isolates were identified as Fusobacterium varium (18/23), Fusobacterium necrophorum subsp. funduliforme (3/23), and Fusobacterium necrophorum subsp. necrophorum (2/23). Using polymerase chain reaction–based detection of virulence genes, all F. necrophorum isolates were positive for the promoter region of the leukotoxin operon and the hemagglutinin-related protein gene, while all F. varium isolates were negative. The presence of the leukotoxin gene in F. necrophorum isolates and the absence of this gene in F. varium isolates were confirmed by Southern hybridization using 2 separate probes. Toxicity to bovine polymorphonuclear leukocytes was observed with all F. necrophorum isolates, but was not observed in any F. varium isolates. Susceptibility to antimicrobials was markedly different for F. varium as compared to F. necrophorum. In summary, no evidence of leukotoxin production was detected in any of the 23 F. varium isolates used in the current study. The data suggests that F. varium, the most common species isolated, may be a significant pathogen in deer with a different virulence mechanism than F. necrophorum.

Microarray analysis of microbiota of gingival lesions in noma patients

Noma (cancrum oris) is a gangrenous disease of unknown etiology affecting the maxillo-facial region of young children in extremely limited resource countries. In an attempt to better understand the microbiological events occurring during this disease, we used phylogenetic and low-density microarrays targeting the 16S rRNA gene to characterize the gingival flora of acute noma and acute necrotizing gingivitis (ANG) lesions, and compared them to healthy control subjects of the same geographical and social background. Our observations raise doubts about Fusobacterium necrophorum, a previously suspected causative agent of noma, as this species was not associated with noma lesions. Various oral pathogens were more abundant in noma lesions, notably Atopobium spp., Prevotella intermedia, Peptostreptococcus spp., Streptococcus pyogenes and Streptococcus anginosus. On the other hand, pathogens associated with periodontal diseases such as Aggregatibacter actinomycetemcomitans, Capnocytophaga spp., Porphyromonas spp. and Fusobacteriales were more abundant in healthy controls. Importantly, the overall loss of bacterial diversity observed in noma samples as well as its homology to that of ANG microbiota supports the hypothesis that ANG might be the immediate step preceding noma.

[Anaerobic bacteria 150 years after their discovery by Pasteur]

In 2011 we celebrated the 150th anniversary of the discovery of anaerobic bacteria by Louis Pasteur. The interest of the biomedical community on such bacteria is still maintained, and is particularly focused on Clostridium difficile. In the past few years important advances in taxonomy have been made due to the genetic, technological and computing developments. Thus, a significant number of new species related to human infections have been characterised, and some already known have been reclassified. At pathogenic level some specimens of anaerobic microflora, that had not been isolated from human infections, have been now isolated in some clinical conditions. There was emergence (or re-emergence) of some species and clinical conditions. Certain anaerobic bacteria have been associated with established infectious syndromes. The virulence of certain strains has increased, and some hypotheses on their participation in certain diseases have been given. In terms of diagnosis, the routine use of MALDI-TOF has led to a shortening of time and a cost reduction in the identification, with an improvement directly related to the improvement of data bases. The application of real-time PCR has been another major progress, and the sequencing of 16srRNA gene and others is currently a reality for several laboratories. Anaerobes have increased their resistance to antimicrobial agents, and the emergence of resistance to carbapenems and metronidazole, and multi-resistance is a current reality. In this situation, linezolid could be an effective alternative for Bacteroides. Fidaxomicin is the only anti-anaerobic agent introduced in the recent years, specifically for the diarrhoea caused by C.difficile. Moreover, some mathematical models have also been proposed in relation with this species.