Description of eight human infections caused by Bacteroides pyogenes in a tertiary hospital of northern Spain.

Bacteroides pyogenes is a Gram-negative obligate anaerobe, saccharolytic, non-motile, non-pigment-producing and non-spore-forming rod. Reports of human infections caused by B. pyogenes are scarce, with approximately 30 cases documented in scientific literature. The aim of this study was to describe the clinical characteristics of 8 different patients and to study the in vitro antibiotic susceptibility of the strains, as well as to evaluate the in vivo activity of the prescribed treatments. We conducted a descriptive retrospective study by searching all B. pyogenes isolates from January 2010 to March 2023 at the Basurto University Hospital. This included all cases, both in monomicrobial or polymicrobial cultures. Among the eight patients, three experienced severe infections such as bacteremia and osteomyelitis. All the strains were susceptible to amoxicillin/clavulanic acid, piperacillin/tazobactam, imipenem, meropenem, clindamycin, metronidazole and moxifloxacin.

Disseminated Nocardia farcinica infection associated with bacteraemia and osteomyelitis pubis in an elderly patient.

OBJECTIVE: We describe a rare case of a disseminated Nocardia farcinica infection associated with hip osteomyelitis. METHODS: A 91-year-old female patient was admitted with oedema of her right leg, fever of 38 °C and data consistent with ruptured Baker's cyst. A disseminated Nocardia farcinica infection including bloodstream infection, pneumonia and multiple abscesses along both lower limbs was observed. RESULTS: After a four-week course of 320 mg/1600 mg/12 h of intravenous trimethoprim/sulfamethoxazole and multiple chirurgic drainages the patient was discharged with oral trimethoprim/sulfamethoxazole. Nevertheless, the patient expired done month after being discharged from the hospital. CONCLUSIONS: The implementation of a combination of intravenous antibiotics and drainages resulted in an initial improvement in the patient's condition. However, despite these interventions, the patient ultimately passed away probably due to natural causes.

Fusobacterium ulcerans: from gut to commensal and bacterial translocation?

The genus Fusobacterium contains currently 13 species presenting as non-sporing, obligate anaerobic, Gram-negative fusiform rods. Fusobacterium ulcerans was discovered in 1988 causing tropical ulcers. We present the case of a patient with diverticulitis complicated with bacteremia. Both aerobic bottles were positive at 20 and 24 h, while one anaerobic bottle was positive at 36 h. Escherichia coli and Fusobacterium ulcerans were identified from subcultures by MALDI-TOF MS with a score of 2.02 and 2.35, respectively. The 16S rRNA gene was sequenced in order to confirm the identification of F. ulcerans with a 100% homology to the reference strain. The patient was treated with 4 g/0,5 g of IV piperacillin/tazobactam and later with 1 g/0,2 g of amoxicillin/clavulanic during 7 days with good clinical evolution.

Is Bacteroides finegoldii a new bacterial pathogen?

Bacteoides finegoldii is a Gram-negative, rod-shaped and obligate anaerobic bacteria isolated in human feces during studies of intestinal microbiota. We present a case report in which B. finegoldii was isolated and identified from the blood culture of a 93-year-old patient with abdominal pain. Microbiological identification was performed by MALDI-TOF MS and confirmed later by 16S rRNA sequencing. An abdomino-pelvic CT scan was conducted, showing a mass of neoplastic appearance that infiltrated the sigmoid colon and bladder, probably producing a colo-vesical fistula. Up to now, this is the first report of B. finegoldii causing human infection.