What we actually know about the pathogenicity of Bacteroides pyogenes

Prolonged Bacteroides pyogenes infection in a patient with multiple lung abscesses

Bacteroides pyogenes is naturally found in the oral microbiome of cats and dogs and hence exposure, especially bites from these animals, is a major risk factor for human infections. B pyogenes is known to cause infections that persist despite antibiotic treatment and can have serious clinical outcomes. We present a novel case of complex lung abscesses associated with B pyogenes infection. A 55 year old man presents with a 3-month history of productive cough, night sweats, and 5 kg weight loss. An initial chest radiograph revealed mass-like opacities in the right upper lobe (RUL), right middle lobe (RML), and left lower lobe (LLL). Over the next 4 years the patient underwent multiple investigations and antimicrobial treatments until resolution of the abscesses. We believe that metronidazole in combination with moxifloxacin was a key component in the clinical cure of this patient.

Unique presentation of an intramuscular abscess caused by Bacteroides pyogenes in the setting of a cat bite: A case report

Cat bites are a relatively common emergency department presentation. The most common species isolated from cat bite wounds is Pasteurella multocida. In this case report, we discuss a unique case of an intramuscular abscess caused by Bacteroides pyogenes. Antibiotic resistance in Bacteroides species is a growing concern and thus should be treated with caution. We present an 81-year-old female who presented to the emergency department with left calf pain that began 3 weeks prior to the emergency department presentation. She was initially seen by her primary care provider and was prescribed oral Trimethoprim/Sulfamethoxazole and Amoxicillin/Clavulanate. Despite oral antibiotics, she began to have worsening swelling, erythema, and fevers. In the emergency department, the patient's left calf was noticeably erythematous and tender to palpation. Lab work showed a C-reactive protein of 12.4 mg/dl, erythrocyte sedimentation rate of 38 mm/h, and white blood cell count of 15.1. Computed tomography imaging showed an irregularly shaped fluid collection at the junction of the calf musculature and upper aspect of the Achilles tendon. The decision was made to perform an operative incision and debridement on the evening of her presentation. On postoperative day 2, the wound cultures grew positive for both Pasturella multocida and Bacteroides pyogenes. She was subsequently discharged with oral Amoxicillin/Clavulanate 875 mg twice daily for 4 weeks. Further studies can be performed to identify the most efficient ways to isolate and treat this species. This case report emphasizes the importance of ordering both aerobic and anaerobic cultures and aiming antimicrobial therapy against both Pasteurella and anaerobic bacteria.

Uterine microbial ecology and disease in cattle: A review

Due to the critical contribution of the uterine-associated microbiota in reproductive health, physiology, and performance, culture-independent methods have been increasingly employed to unravel key aspects of microbial ecology in the uterus of cattle. Nowadays, we know that bacterial diversity is crucial to maintain uterine health, however, there is still no consensus on the exact composition of a healthy uterine microbiota (or eubiosis). Generally, loss of bacterial diversity (or dysbiosis) contributes to the development of uterine infections, associated with increased relative abundances of Bacteroides, Fusobacterium, Trueperella, and Porphyromonas. Uterine infections are highly prevalent and gravely influence the profitability of cattle operations, animal welfare, and public health. Thus, understanding the dynamics of uterine microbial ecology is essential to develop effective strategies focused on preventing and mitigating the adverse effects of uterine dysbiosis as well as assisting in the process of restoring the core, healthy uterine microbiota. The aim of this review is to summarize research conducted in the microbial ecology of bovine uteri. We discuss the origin of the uterine microflora of healthy cows and the factors influencing its composition. In addition, we review the biology of specific pathogens that are known to increase in abundance during the occurrence of uterine disease. Lastly, we provide an overview of the bacterial biofilm in the bovine endometrium, and we briefly summarize the rationale for the use of probiotics to prevent uterine disease in cattle.

Meningoencephalomyelitis associated with foreign plant material in a dog: case report and brief literature review

Neurologic disease associated with migration of plant material is reported infrequently in dogs. Here we describe meningoencephalomyelitis associated with foreign plant material in a 2-y-old castrated male West Highland White Terrier dog with acute neck pain. Magnetic resonance imaging revealed spinal meningeal contrast enhancement. Although clinical signs improved after treatment with steroids, the dog was readmitted for further evaluation 3-mo later and was euthanized after generalized epileptic seizures. Autopsy findings consisted of coalescing, pus-filled, neuroparenchymal cavitations surrounded by hemorrhage in the left caudal colliculus and rostral left cerebellar hemisphere. Histologically, lesions consisted of necrosis and suppuration, which surrounded a 1 × 2-mm foreign body morphologically consistent with plant material and clusters of gram-positive bacterial cocci. Affected areas were surrounded by reactive astrocytes, fibrous connective tissue, and mixed inflammatory infiltrates. Areas of hemorrhage and infiltration by neutrophils and foamy macrophages with fibrinoid change of small capillaries were observed in the adjacent neuroparenchyma. The inflammation extended to the perivascular spaces in the leptomeninges (mesencephalon, cerebellum, and brainstem, and spinal cord) and spinal central canal. Anaerobic bacterial culture of frozen samples of cerebellum yielded heavy growth of Bacteroides pyogenes.

Volatile Sulfur Compounds Produced by the Anaerobic Bacteria Porphyromonas spp. Isolated from the Oral Cavities of Dogs

Porphyromonas spp. are oral anaerobic Gram-negative bacteria that form black-pigmented colonies on blood agar and produce volatile sulfur compounds (VSCs), such as hydrogen sulfide (H2S), methyl mercaptan (CH3SH), and dimethyl sulfide ((CH3)2S), which cause halitosis and the destruction of periodontal tissues. P. gulae is considered the main pathogen involved in periodontal disease in dogs. However, the characteristics of the VSCs produced by P. gulae are unknown. In the present study, VSCs were measured in 26 isolates of P. gulae and some isolates of the other Porphyromonas spp. obtained from the oral cavities of dogs with periodontal disease using an in vitro assay with an Oral ChromaTM gas chromatograph. The results demonstrated that P. gulae was able to produce large amounts of H2S and CH3SH, and the dominant product was CH3SH (CH3SH/H2S was approximately 2.2). Other Porphyromonas spp. that were also obtained from the oral cavities of dogs with periodontal disease indicated similar levels of production of H2S and CH3SH to those of P. gulae. It is strongly suggested that the high levels of H2S and CH3SH produced by P. gulae and other Porphyromonas spp. contribute to halitosis and the destruction of periodontal tissues during the progression of periodontal disease in dogs.

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.

Insights into the Genital Microbiota of Women Who Experienced Fetal Death in Utero

The aim of this work was to achieve a better understanding of the bacterial pathogens associated with stillbirths that would serve to inform clinical interventions directed at reducing this adverse pregnancy outcome. A prospective observational study was conducted with the participation of 22 women from northern Peru, of whom 11 experienced fetal death in utero and 11 delivered preterm births. Swabs were taken from the vagina, placenta, amniotic fluid and axilla of the infant at birth by Caesarean section. The bacterial populations in the vagina and the amniotic space of each participant were determined by employing the amplicon sequencing of the V4 region of the 16S rRNA genes. The sequence data were analysed using bioinformatics tools. The work showed differences in the composition of the genital microbiomes of women who experienced preterm birth or fetal death in utero. There were no differences in the alpha diversity between the genital microbiotas of both groups of women, but there were more different taxa in the vagina and amniotic space of the preterm participants. Lactobacillus spp. was less abundant in the stillbirth cases. E. coli/Shigella, Staphylococcus, Gardnerella, Listeria and Bacteroides taxa were associated with the stillbirths. In each woman, there was a minimal concordance between the bacterial populations in the vagina and amniotic space.

C-phycocyanin alleviated cisplatin-induced oxidative stress and inflammation via gut microbiota—metabolites axis in mice

C-phycocyanin is a natural protein extracted from Spirulina platensis. We aim to investigate the preventive effect of C-phycocyanin on cisplatin chemotherapy-induced oxidative damage and inflammation. The result showed that C-phycocyanin treatment reduced cisplatin-induced mortality and inflammation including decreased levels of serum IL6, kidney MCP1, and liver IL1β. Furthermore, C-phycocyanin also exerted antioxidant effects on mice, including increased GSH-Px, GGT, and GSH levels in the liver and increased CAT and SOD levels in the kidney. HepG2 cells experiments showed that C-phycocyanin exhibited none of the prevention effects on cisplatin injury. Faecalibaculum showed the greatest reduction among genera after cisplatin treatment, which was related to the enrichment of Romboutsia and Lactobacillus genera. C-phycocyanin treatment reduced the populations of harmful bacteria of Enterococcus faecalis, which was positively correlated with inflammation induced by cisplatin. C-phycocyanin increased the contents of 23-nordeoxycholic acid and β-muricholic acid. Moreover, C-phycocyanin increased amino acid-related metabolites, Nα-acetyl-arginine and trimethyl-lysine contents, and decreased fatty acid esters of hydroxy fatty acids (FAHFAs) contents. In conclusion, C-phycocyanin inhibited inflammation via the 23-nordeoxycholic acid-Enterococcus faecalis-inflammation axis, and enhanced the antioxidant capacity of kidney via Lactobacillus-NRF2 pathway. C-phycocyanin alleviated cisplatin injury via the modulation of gut microbiota, especially Lactobacillus and Enterococcus, as well as regulation of metabolites, especially bile acid and FAHFAs, which highlight the effect of C-phycocyanin and provide a new strategy to prevent cisplatin injury.

Vaginal microbiota signatures in healthy and purulent vulvar discharge sows

Purulent vulvar discharges, primarily caused by genito-urinary tract infections, are an important source of economic loss for swine producers due to sow culling and mortality. However, the agents that compose the vaginal microbiota of sows and their changes during infections are not well understood. The first goal of this study was to characterize and compare the vaginal bacterial content of healthy (HE, n = 40) and purulent vulvar discharge sows (VD, n = 270) by a culture-dependent method and MALDI-TOF MS identification. Secondly, we performed 16S rRNA targeted metagenomic approach (n = 72) to compare the vaginal microbiota between these groups. We found a wide variety of bacteria, with Proteobacteria, Firmicutes, and Bacteroidota being the most abundant phyla in both groups, as well as Escherichia-Shigella, Streptococcus, and Bacteroides at the genus level. Most agents identified in the sequencing method also grew in the culture-dependent method, showing the viability of these bacteria. Alpha diversity did not differ between HE and VD sows, regarding sample richness and diversity, but a beta-diversity index showed a different microbiota composition between these groups in two tested herds. ANCOM analysis revealed that Bacteroides pyogenes were more abundant in VD females and can be a marker for this group. Other agents also require attention, such as the Streptococcus dysgalactiae and Staphylococcus hyicus found in remarkably greater relative abundance in VD sows. Network analysis revealed important positive correlations between some potentially pathogenic genera, such as between Escherichia-Shigella, Trueperella, Streptococcus, Corynebacterium, and Prevotella, which did not occur in healthy sows. We conclude that the alteration of the vaginal microbiota between healthy and purulent vulvar discharge sows, although not extreme, could be due to the increase in the relative abundance of specific agents and to associations between potentially pathogenic bacteria.