Bacteremia caused by Desulfovibrio desulfuricans with the intestinal tract as the portal of entry: two case reports and a literature review.

BACKGROUND: Desulfovibrio desulfuricans (D. desulfuricans), a commensal anaerobic gram-negative rod endemic to the soil environment and human gastrointestinal tract, rarely causes bloodstream infections. We report two rare cases of bacteremia caused by D. desulfuricans in which the intestinal tract was the portal of entry. In addition, we summarize findings on D. desulfuricans. CASE PRESENTATION: Case 1: A 51-year-old man presented to the emergency department with the chief complaints of fever and right lower abdominal pain. He was admitted to the hospital with ascending colonic diverticulitis and received empirical antibacterial therapy with piperacillin/tazobactam. Blood culture revealed D. desulfuricans. The patient was discharged after 2 weeks of antimicrobial therapy. Case 2: A 95-year-old woman presented to our hospital with a chief complaint of fever. Owing to an elevated inflammatory response and pyuria, the patient was diagnosed with pyelonephritis and treated with ceftriaxone. Klebsiella pneumoniae was detected in her urine culture, while D. desulfuricans was detected in her blood culture. The patient was then treated with ampicillin/sulbactam for 14 days. The fecal occult blood test result was positive, suggesting a colonic mucosal lesion, such as a malignant tumor, may have been the portal of entry for D. desulfuricans bacteremia. Previous literature reviews indicate that D. desulfuricans bacteremia often results from liver or renal abscesses, intestinal lesions, among others, serving as the portal of entry. Although no specific underlying disease has been reported, it is more common in the older population. We encountered two cases of D. desulfuricans bacteremia and combined them with 15 cases from previous studies to explore the characteristics of the disease. The proportion of patients aged [Formula: see text]60 years was 73.7%; overall, 73.7% had gastrointestinal complications, and 63.2% had abdominal symptoms at the time of presentation. CONCLUSIONS: We encountered two rare cases of D. desulfurican bacteremia. This type of bacteremia is more common in elderly people over 60 years of age and is often associated with hepatobiliary and gastrointestinal diseases.

Desulfovibrio desulfuricans and its derived metabolites confer resistance to FOLFOX through METTL3.

BACKGROUND: Chemoresistance is a critical factor contributing to poor prognosis in clinical patients with cancer undergoing postoperative adjuvant chemotherapy. The role of gut microbiota in mediating resistance to tumour chemotherapy remains to be investigated. METHODS: Patients with CRC were categorised into clinical benefit responders (CBR) and no clinical benefit responders (NCB) based on chemotherapy efficacy. Differential bacterial analysis using 16S rRNA sequencing revealed Desulfovibrio as a distinct microbe between the two groups. Employing a syngeneic transplantation model, we assessed the effect of Desulfovibrio on chemotherapy by measuring tumour burden, weight, and Ki-67 expression. We further explored the mechanisms underlying the compromised chemotherapeutic efficacy of Desulfovibrio using metabolomics, western blotting, colony formation, and cell apoptosis assays. FINDINGS: In comparison, Desulfovibrio was more abundant in the NCB group. In vivo experiments revealed that Desulfovibrio colonisation in the gut weakened the efficacy of FOLFOX. Treatment with Desulfovibrio desulfuricans elevates serum S-adenosylmethionine (SAM) levels. Interestingly, SAM reduced the sensitivity of CRC cells to FOLFOX, thereby promoting the growth of CRC tumours. These experiments suggest that SAM promotes the growth and metastasis of CRC by driving the expression of methyltransferase-like 3 (METTL3). INTERPRETATION: A high abundance of Desulfovibrio in the intestines indicates poor therapeutic outcomes for postoperative neoadjuvant FOLFOX chemotherapy in CRC. Desulfovibrio drives the manifestation of METTL3 in CRC, promoting resistance to FOLFOX chemotherapy by increasing the concentration of SAM. FUNDING: This study is supported by Wuxi City Social Development Science and Technology Demonstration Project (N20201005).

Análise de limas endodônticas submetidas a biocorrosão por bactérias redutoras de sulfato in vitro / Analysis of endodontic files submitted to biocorrosion by sulfate reducing bacteria in vitro

Objetivo: Avaliar as alterações químicas presentes na superfície metálica de limas endodônticas fraturadas em canais radiculares, in vitro, após a inoculação intrarradicular de culturas de BRS de três cepas microbianas, Desulfovibrio desulfuricans (uma cepa oral e outra ambiental) e Desulfovibrio fairfieldensis. Métodos: foram analisadas 5 limas kerr #90, sendo uma Lima Kerr nova, sem tratamento, e as outras 4 limas fraturadas dentro de canais radiculares in vitro, com posterior inoculação de Desulfovibrio desulfuricans, cepa oral e ambiental, e Desulfovibrio fairfieldensis e um grupo controle sem inoculação bacteriana, por 477 dias. Os grupos foram analisados no modo EDS (Espectrometria de Energia Dispersiva de Raios-x) do microscópio eletrônico de varredura (FEI-Inspect-S50). Resultados:A presença do S, Cl e O foram relacionados ao processo biocorrosivo, assim como a redução dos elementos de liga nesta área. Conclusão:As análises no modo EDS demonstraram biocorrosão ao longo da superfície metálica das limas quando empregado o biofármaco BACCOR, nas três diferentes cepas empregadas, indicada pela redução dos elementos formadores da liga metálica, Fe, Ni e Cr, com a associação da presença de elementos indicadores de biocorrosão como O, Cl e S. (AU)

Aim:To evaluate the chemical alterations present on the metallic surface of root canal fractured endodontic files in vitro after the intraradicular inoculation of BRS cultures of three microbial strains, Desulfovibrio desulfuricans (one oral and one environmental strain), and Desulfovibrio fairfieldensis. Methods: Five kerr #90 files were analyzed, one new untreated Kerr file and the other 4 files fractured within root canals in vitro, with a subsequent inoculation of Desulfovibrio desulfuricans (oral and environmental strains), and Desulfovibrio fairfieldensis, as well as a control group without bacterial inoculation for 477 days. The groups were analyzed using the scanning electron microscope (FEI-Inspect-S50) EDS (X-ray Dispersive Energy Spectrometry) mode. Results:The presence of S, Cl, and O were related to the biocorrosive process, as well as the reduction of alloying elements in this area. Conclusion: The EDS mode analysis showed biocorrosion along the metallic surface of the files when the BACCOR biopharmaceutical was used in the three different strains employed in this study, indicated by the reduction of the alloying elements ­ Fe, Ni, and Cr ­ with the association of the presence of indicator elements of biocorrosion, such as O, Cl, and S. (AU)

Anaerobiospirillum succiniciproducens y Desulfovibrio desulfuricans en 2 casos de bacteriemias insidiosas / Anaerobiospirillum succiniciproducens and Desulfovibrio desulfuricans in 2 cases of insidious bacteremia

Se presentan 2 casos de bacteriemias insidiosas por bacilos gram negativos anaerobios curvos, espiralados, móviles e infrecuentes en pacientes atendidos en un hospital de la ciudad de Buenos Aires. Estas bacteriemias, asociadas al aislamiento de Anaerobiospirillum y Desulfovibrio, fueron de origen poco claro y afectaron a pacientes inmunocomprometidos, con patologías simultáneas. Pruebas claves en la identificación del género Anaerobiospirillum fueron el estudio de la micromorfología, su carácter de anaerobio estricto, el resultado negativo en la prueba de catalasa, el patrón de discos de interés taxonómico, la fermentación de glucosa y la producción de β-N-acetilglucosaminidasa. El género Desulfovibrio se diferenció por el perfil presentado en las pruebas con discos, por ser asacarolítico, sin actividad de enzimas glucosídicas, y por producir desulfoviridina y H2S. Se alerta sobre la resistencia o sensibilidad intermedia de Anaerobiospirillum succiniciproducens (especie a la que correspondió el aislado de Anaerobiospirillum) a algunos de los antimicrobianos de primera línea frente a bacilos gram negativos anaerobios, como el metronidazol; fueron activas las combinaciones de aminopenicilinas con inhibidores de β-lactamasas y el imipenem. Desulfovibrio desulfuricans (especie a la que correspondió el aislado de Desulfovibrio) fue productora de β-lactamasas y resistente a las cefalosporinas; en cambio, fueron activos el metronidazol, el imipenem y la levofloxacina. La identificación confiable de estos microorganismos orienta hacia el mejor esquema terapéutico.

Two cases of insidious bacteremia by uncommon curve and spiral-shaped, motile anaerobic gram-negative rods are presented. Both of them were of an unclear origin and occurred in immunosuppressed patients with simultaneous diseases. The key tests for the identification of Anaerobiospirillum were its micromorphology, a strictly anaerobic condition, negative catalase activity, the special-potency disk profile, glucose fermentation, and β-NAG production. Desulfovibrio species was identified by all the above preliminary tests but with a different disk profile, as well as for being asaccharolytic and desulfoviridin and H2S producer. We here alert about the resistance or intermediate susceptibility of Anaerobiospirillum succiniciproducens against antimicrobial agents, such as metronidazole, one of the first-line drugs used for the treatment of anaerobic gram-negative infections. Aminopenicillins with β-lactamase-inhibitor combinations and imipenem were active for this agent. Desulfovibrio desulfuricans was β-lactamase producer and resistant to cephalosporins, while metronidazole, imipenem and levofloxacin were active. A reliable identification of these microorganisms is important for establishing the best therapeutic scheme.