Eubacterium species are a group of obligated anaerobic gram-positive bacilli that are recognized as commensals of the gastrointestinal tract flora. Cases of bacteremia mediated by Eubacterium are rare. This report describes a case of bacteremia caused by Eubacterium callanderi in an 82-year-old female with a history of a cecal perforation secondary to an obstructing sigmoid stricture. The results showed the utility of using whole genome sequencing to identify the causative agent and underlined the significance to identify anaerobic organisms in diagnostic microbiology practice and to perform antimicrobial susceptibility testing to guide therapy and enhance patient outcomes.

Pantoea, a gram-negative, rod-shaped, anaerobic bacterium, is a rare cause of human disease. Pantoea species have been known to mostly cause pulmonary disease in agricultural workers as they are native to select crops and wild animal furs. However, in very few documented cases, Pantoea has been discovered as the source of nosocomial infections, usually in the setting of an immunocompromised host. This case report details the clinical course of a 62-year-old immunocompromised female with stage 3 breast cancer presenting with acute cholecystitis and bacteremia and the unexpected discovery of Pantoea in peripheral and chemotherapy port blood cultures. After appropriate management and susceptibility testing, the patient fortunately recovered with initial cefepime and eventual levofloxacin to target the Pantoea species. To our knowledge, this is the third documented case worldwide of Pantoea isolated from cholecystitis with associated bacteremia and the first documented case in North America. Of special interest, a few months after her infection, the patient was found to be free of breast cancer. Pantoea species are known to contain levan, an exopolysaccharide, that has been seen to upregulate tumor suppressor genes. This should be considered in the future management and research of Pantoea infections.

Background and Objectives: Anaerobic bacteria like Fusobacterium can lead to severe and life-threatening infections. The inherent complexities in the isolation of these bacteria may result in diagnostic and therapeutic delays, thereby escalating both morbidity and mortality rates. We aimed to examine data from patients with infections due to Fusobacterium to gain insights into the epidemiology and clinical outcomes of patients with these infections. Methods and Results: We conducted a retrospective analysis of clinical data from a cohort of patients with cultures positive for Fusobacterium species at a tertiary care medical center in the United States. Between 2009 and 2015, we identified 96 patients with cultures positive for Fusobacterium. Patients could be categorized into three groups based on the site of primary infection. Patients with head and neck infections constituted 37% (n 36). Patients with infections of other soft tissue sites accounted for 38.5% (n 37). Patients with anaerobic bacteremia due to Fusobacterium formed 24% (n 23) of the cohort. Surgical intervention coupled with antibiotic therapy emerged as cornerstones of management for patients with head and neck or other soft tissue infections, who generally exhibited more favorable outcomes. Patients with bacteremia were older, more likely to have malignancy, and had a high mortality rate. When speciation was available, Fusobacterium necrophorum was the most frequently isolated species. Conclusions: Our retrospective analysis of epidemiology and clinical outcomes of Fusobacterium infections revealed three distinct cohorts. Patients with head, neck, or soft tissue infections had better outcomes than those with bacteremia. Our findings highlight the importance of employing management strategies based on infection site and underlying comorbidities in patients with Fusobacterium infections. Further research is needed to investigate the optimal therapeutic strategies and identify prognostic indicators to improve clinical outcomes for these complex infections.

UNASSIGNED: Metronidazole treats obligate anaerobic bacterial and protozoal infections, with an elimination half-life of around 8 hours. The long elimination half-life, the favorable ratio of steady-state serum levels to minimum inhibitory concentration, and the presence of active metabolites have led to the consideration of metronidazole use at 12-hour dosage intervals. This systematic review aimed to compare the clinical outcomes of twice-daily and thrice-daily metronidazole dosing.
UNASSIGNED: Using the PRISMA checklist, we searched five databases to systematically identify all relevant studies published up to June 16, 2023.
UNASSIGNED: The final analysis included two published retrospective cohort studies of hospitalized adult patients: a single site study (n = 200) and a multisite study (n = 85) of \"good\" quality, as measured by the Newcastle-Ottawa scale. The reported baseline characteristics of the 8-hour and 12-hour dosing groups were comparable, and neither study identified significant differences in primary and secondary clinical outcomes. Metaanalysis of the need to escalate antibiotic therapy also showed no statistically significant differences using the Mantel-Haenszel fixed-effect method (95% confidence interval: 47.6% lower to 6.4 times higher risk, P = 0.34) and inverse-variance method (risk ratio: 1.87; 95% confidence interval: 0.52-6.65, P = 0.34).
UNASSIGNED: This review suggests that dosing metronidazole every 12 hours is as effective as every-8-hour dosing for hospitalized patients with anaerobic infections. These encouraging findings would benefit from validation by a multicenter randomized controlled trial since there would be many benefits to a 12-hour dosing interval while achieving similar clinical outcomes with traditional dosing. The studies in this systematic review excluded patients with Clostridioides difficile and central nervous system and amebiasis infections, so the findings do not apply to these infection types.

Parvimonas micra is a gram-positive anaerobic coccus (GPAC) that colonizes the oral cavity and gastrointestinal tract. Recent advances in bacterial identification have confirmed the clinical importance of Parvimonas micra. Here, we report a case of empyema with bacteremia caused by Parvimonas micra. We successfully treated the patient with the appropriate antibiotics and drainage. Parvimonas micra can cause respiratory infections, including empyema, which can progress to bacteremia if treatment is delayed. In Parvimonas micra infections, not only the oral cavity but also the entire body must be investigated to clarify the entry mechanism.

A pediatric patient suffered from renal and hepatic abscesses (through hepatorenal space) and recovered by antibiotics and other therapies. By clinical analysis, the multi-organ abscesses might be caused by bloodstream-disseminated infection. In order to identify the pathogen, we collected kidney biopsy tissue, swabs, and plasma samples, and used metagenomics next-generation sequencing (mNGS) and some traditional methods. The results revealed that polymicrobial especially anaerobic bacteremia (Bacteroides fragilis, et al.) contributed to the abscess formation. What is more, systematic human adenovirus C (HAdV-C) infection was shown, and the virus was isolated. The titer of HAdV-2 neutralizing antibodies was 1/4 in the plasma after symptoms onset. Although the exact mechanism of HAdV-2 infection in multiple abscess formation has not been clarified, the case of multi-organ abscesses in the context of polymicrobial especially anaerobic bacteremia and HAdV infection in healthy children is infrequent.

This was a multicenter, retrospective study of patients with anaerobic bacteremia comparing metronidazole 500 mg every 8 h versus 500 mg every 12 h. Of 782 patients reviewed, 85 met inclusion criteria. There was no significant difference in mortality, length of stay, or escalation of therapy between dosing strategies.

The effect of antimicrobial stewardship (AS) on anaerobic bacteremia is uncertain. This study aimed to assess the effect of interventions by the AS team (AST) on clinical and microbiological outcomes and antimicrobial use. An AS program was introduced at Osaka City University Hospital in January 2014; an interdisciplinary AST was established. We enrolled patients with anaerobic bacteremia between January 2009 and December 2018. Patients were classified into the pre-intervention group (from January 2009 to December 2013) and the post-intervention group (from January 2014 to December 2018). A significant decrease in definitive carbapenem use (P = 0.0242) and an increase in empiric tazobactam/piperacillin use (P = 0.0262) were observed in the post-intervention group. The de-escalation rate increased significantly from 9.38% to 32.7% (P = 0.0316) in the post-intervention group. The susceptibility of Bacteroides species and 30-day mortality did not worsen in the post-intervention group. These results showed that interventions by an AST can reduce carbapenem use and increase the de-escalation rate without worsening patient outcomes.

BACKGROUND: Parvimonas micra is a gram-positive anaerobe and a part of the normal commensal flora of the gastrointestinal tract. Factors predisposing to anaerobic bacteremia include malignant neoplasms, periodontal disease, immune deficiencies, chronic renal insufficiency, decubitus ulcers and perforated abdominal viscus. Cases of Parvimonas bacteremia in a patient with esophageal carcinoma and in a patient following ERCP procedure have been reported but to our best knowledge no case has been reported yet in which a patient had colonic carcinoma.
METHODS: We present a rare case of a 94-year-old male who presented with chief complaint of fever and constipation. Complete blood count revealed normal white blood cell count anemia. Urinalysis came out to be unremarkable for any evidence of infection. Two blood cultures grew Parvimonas micra and Gamella morbillorum and patient was later switched to ampicillin-sulbactam as per blood culture susceptibility results. Echocardiogram came negative for any evidence of infective endocarditis. CT abdomen/pelvis showed soft tissue mass in the ascending colon just superior to the ileocecal valve (fig.1, 2). Colonoscopy showed non-obstructing eccentric mass (fig. 3). Biopsy of the mass revealed moderately differentiated adenocarcinoma. Because of lack of distant metastasis, surgical resection of the mass as definitive curative treatment was done.
CONCLUSIONS: Immune deficiency is a risk factor for anaerobic bacteremia. Apart from immediately starting the patient on antibiotics, a thorough search for malignancy may be considered when a patient presents with anaerobic bacteremia, especially, when the source of infection is not known. Identifying malignancy in earliest stages may improve treatment outcome.

BACKGROUND: Investigation on incidence and mortality of anaerobic bacteremia (AB) is clinically relevant in spite of its infrequent occurrence and not often explored, which report varies according to period and institutions. Therefore, it is necessary to analyze the incidence and risk factors related to mortality and assess clinical outcomes of AB in current aspect.
METHODS: Characteristics of AB patients and anaerobic bacteria from blood culture at a university hospital in 2012 were reviewed retrospectively. The correlation between risk factors and 28-day patient mortality was analyzed.
RESULTS: A total of 70 non-duplicated anaerobic bacteria were isolated from blood of 70 bacteremia patients in 2012. The history of cardiovascular disease as host\'s risk factor was statistically significant (P = 0.0344) in univariate and multivariate analysis. Although the inappropriate therapy was not statistically significant in univariate and multivariate analysis, the survival rate of bacteremia was significantly worse in patients who had inappropriate therapy compared with those underwent appropriate therapy (hazard ratio, 5.4; 95% confidence interval, 1.7-6.9; P = 0.004). The most frequently isolated organism was Bacteroides fragilis (32 isolates, 46%), followed by Bacteroides thetaiotaomicron (10, 14%), and non-perfringens Clostridium (7, 10%).
CONCLUSIONS: The incidence of AB in 2012 was 2.3% (number of AB patients per 100 positive blood culture patients) and the mortality rate in patients with clinically significant AB was 21.4%. In addition, AB was frequently noted in patients having malignancy and the survival rate of AB was significantly worse in patients who received inappropriate therapy compared with those underwent appropriate therapy.