MALDI-TOF MS in Anaerobiospirillum succiniciproducens bacteremia: A report of 4 cases in different hosts

Amidinoquinoxaline N-oxides: synthesis and activity against anaerobic bacteria

We present herein an in-depth study on the activity of amidinoquinoxaline N-oxides 1 against Gram-positive and Gram-negative anaerobic bacteria. Based on 5-phenyl-2,3-dihydropyrimidoquinoxaline N-oxide 1a, the selected structural variations included in our study comprise the substituents α- to the N-oxide function, the benzofused ring, substitution and quaternization of the amidine moiety, and the amidine ring size. Compounds 1 showed good to excellent antianaerobic activity, evaluated as the corresponding CIM50 and CIM90 values, and an antimicrobial spectrum similar to metronidazole. Six out of 13 compounds 1 had CIM90 values significantly lower than the reference drug. Among them, imidazoline derivatives 1i-l were the most active structures. Such compounds were synthesized by base-promoted ring closure of the corresponding amidines. The N-oxides under study showed no significant cytotoxicity against RAW 264.7 cells, with high selectivity indexes. Their calculated ADME properties indicate that the compounds are potentially good oral drug candidates. The antianaerobic activity correlated satisfactorily with the electron affinity of the compounds, suggesting that they may undergo bioreductive activation before exerting their antibacterial activity.

Antimicrobial Peptides Relieve Transportation Stress in Ragdoll Cats by Regulating the Gut Microbiota

Transportation is common in cats and often causes stress and intestinal disorders. Antimicrobial peptides (AMPs) exhibit a broad spectrum of antibacterial activity, and they may have the capacity for antioxidant and immune regulation. The objective of this study was to investigate the effects of dietary supplementation with AMPs on stress response, gut microbiota and metabolites of cats that have undergone transport stress. A total of 14 Ragdoll cats were randomly allocated into 2 treatments: basal diet (CON) and a basal diet supplemented with 0.3% AMPs. After a 6-week feeding period, all cats were transported for 3 h and, then, fed for another week. The results show that the diarrhea rate of cats was markedly reduced by supplementation with AMPs throughout the trial period (p < 0.05). In addition, AMPs significantly reduced serum cortisol and serum amyloid A (p < 0.05) and increased apolipoprotein 1 after transportation (p < 0.05). Moreover, AMPs reduced the level of inflammatory factors in the serum caused by transportation stress, including tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) (p < 0.05). The AMPs enhanced the activities of glutathione peroxidase (p < 0.01) and superoxide dismutase (p < 0.05). Furthermore, cats fed AMPs had higher levels of branched chain fatty acids (BCFAs) and a relative abundance of Blautia and a lower relative abundance of Negativibacillus after transportation (p < 0.05). The serum metabolome analysis further revealed that AMPs markedly regulated lipid metabolism by upregulating cholic acid expression. In conclusion, AMP supplementation alleviated oxidative stress and inflammatory response in transportation by regulating the gut microbiota and metabolites, thereby relieving stress-induced diarrhea and supporting gut and host health in cats.

Anaerobiospirillum succiniciproducens prosthetic joint infection

Anaerobiospirillum succiniciproducens is a rare anaerobic pathogen that is implicated in sporadic cases of bacteremia and diarrhea, usually in immunocompromised patients. We describe a case of prosthetic joint infection in a 71 year old male who presented with right hip pain. Anaerobic cultures from tissue specimen grew a spiral-shaped gram-negative rod, identified as A. succiniciproducens by 16S rRNA gene sequencing. The patient was treated successfully with IV cefoxitin for 6 weeks. To our knowledge this is only the third reported case of prosthetic joint infection due to A. succiniciproducens.

MALDI-TOF MS for rapid diagnosis of Anaerobiospirillum succiniciproducens, an unusual causative agent of bacteraemia in humans. Two case reports and literature review

Anaerobiospirillum succiniciproducens is a gram-negative anaerobic spiral rod which is part of the normal flora of dogs and cats and can produce bacteraemia and diarrhoea in humans. In this report we describe two cases of bacteraemia caused by A. succiniciproducens which was successfully identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). We present a comprehensive literature review of 48 cases of A. succiniciproducens bacteraemia in which we describe previous underlying conditions, clinical presentations, identification methodology and antibiotic susceptibility data.