Target next-generation sequencing for the accurate diagnosis of Parvimonas micra lung abscess: a case series and literature review.

Background: Parvimonas micra (P. micra) has been identified as a pathogen capable of causing lung abscesses; however, its identification poses challenges due to the specialized culture conditions for anaerobic bacterial isolation. Only a few cases of lung abscesses caused by P. micra infection have been reported. Therefore, we describe the clinical characteristics of lung abscesses due to P. micra based on our case series. Methods: A retrospective analysis was conducted on eight patients who were diagnosed with lung abscesses attributed to P. micra. Detection of P. micra was accomplished through target next-generation sequencing (tNGS). A systematic search of the PubMed database using keywords "lung abscess" and "Parvimonas micra/Peptostreptococcus micros" was performed to review published literature pertaining to similar cases. Results: Among the eight patients reviewed, all exhibited poor oral hygiene, with four presenting with comorbid diabetes. Chest computed tomography (CT) showed high-density mass shadows with necrosis and small cavities in the middle. Bronchoscopic examination revealed purulent sputum and bronchial mucosal inflammation. Thick secretions obstructed the airway, leading to the poor drainage of pus, and the formation of local abscesses leading to irresponsive to antibiotic therapy, which finally protracted recovery time. P. micra was successfully identified in bronchoalveolar lavage fluid (BALF) samples from all eight patients using tNGS; in contrast, sputum and BALF bacterial cultures yielded negative results, with P. micra cultured from only one empyema sample. Following appropriate antibiotic therapy, seven patients recovered. In previously documented cases, favorable outcomes were observed in 77.8% of individuals treated with antibiotics and 22.2% were cured after surgical interventions for P. micra lung abscesses. Conclusions: This study enriches our understanding of the clinical characteristics associated with lung abscesses attributed to P. micra. Importantly, tNGS has emerged as a rapid and effective diagnostic test in scenarios where traditional sputum cultures are negative. Encouragingly, patients with lung abscesses caused by P. micra infection exhibit a favorable prognosis with effective airway clearance and judicious anti-infective management.

Parvimonas micra-induced prosthetic valve endocarditis: a challenging case report and literature review.

Parvimonas micra, a gram-positive anaerobic bacterium, has garnered increased attention due to its role in infective endocarditis. We present a challenging prosthetic valve endocarditis caused by Parvimonas micra in a patient with a complex cardiac history involving multiple surgeries. The case highlights the difficulties in diagnosis and treatment, emphasizing the importance of advanced diagnostic techniques, including metagenomics next-generation sequencing (mNGS). Additionally, it underscores the need for heightened vigilance regarding oral symptoms and the potential risk of bacteremia in post-valvular surgery patients. This report contributes to a better understanding of Parvimonas micra-associated endocarditis and its unique characteristics.

Complete genome sequence of Parvimonas micra strain JM503A, a genetically tractable dental abscess clinical isolate.

Parvimonas micra is a pathobiont of humans that is often found in abundance at sites of mucosal inflammation as well as within malignant tumors. Here, we report the complete genome sequence of P. micra strain JM503A, which is a genetically tractable clinical isolate derived from a human odontogenic abscess specimen.

Parvimonas micra Bacteremia: A Rare Complication After Esophagogastroduodenoscopy for Upper Gastrointestinal Bleeding.

Parvimonas micra bacteremia is rarely encountered in clinical practice. When it is, patients usually have underlying periodontal disease or colorectal carcinoma. To the best of our knowledge, this is the first case of P. micra bacteremia in a patient without the predisposing risk factors listed above. We postulate that this occurred because of translocation across an interrupted gut-blood barrier in the setting of an acute upper gastrointestinal bleed. We present this case to highlight the importance of identifying and treating P. micra bacteremia because it can prevent commonly encountered sequelae of untreated bacteremia and improve outcomes.

Metagenomic next-generation sequencing identified a brain abscess caused by mixed oral anaerobe infection: A case report.

Fusobacterium vincentii brain abscesses are relatively rare. Here, we report our treatment of an anaerobic brain abscess caused by a mixed infection of Parvimonas micra, Streptococcus constellatus, Fusobacterium vincentii, and Bacteroides heparinolyticus diagnosed by metagenomic next-generation sequencing (mNGS). This is the first reported case of Fusobacterium vincentii in a brain abscess. This case highlights the possibility that oral anaerobic microbes can cause a brain abscess and demonstrates that mNGS has the potential to be deployed to provide rapid infection diagnosis and rationalize antimicrobial therapy for brain abscesses.

Extracellular vesicles from Aggregatibacter actinomycetemcomitans exhibit potential antitumorigenic effects in oral cancer: a comparative in vitro study.

Aggregatibacter actinomycetemcomitans is an opportunistic Gram-negative periodontopathogen strongly associated with periodontitis and infective endocarditis. Recent evidence suggests that periodontopathogens can influence the initiation and progression of oral squamous cell carcinoma (OSCC). Herein we aimed to investigate the effect of A. actinomycetemcomitans-derived extracellular vesicles (EVs) on OSCC cell behavior compared with EVs from periodontopathogens known to associate with carcinogenesis. EVs were isolated from: A. actinomycetemcomitans and its mutant strains lacking the cytolethal distending toxin (CDT) or lipopolysaccharide (LPS) O-antigen; Porphyromonas gingivalis; Fusobacterium nucleatum; and Parvimonas micra. The effect of EVs on primary and metastatic OSCC cells was assessed using cell proliferation, apoptosis, migration, invasion, and tubulogenesis assays. A. actinomycetemcomitans-derived EVs reduced the metastatic cancer cell proliferation, invasion, tubulogenesis, and increased apoptosis, mostly in CDT- and LPS O-antigen-dependent manner. EVs from F. nucleatum impaired the metastatic cancer cell proliferation and induced the apoptosis rates in all OSCC cell lines. EVs enhanced cancer cell migration regardless of bacterial species. In sum, this is the first study demonstrating the influence of A. actinomycetemcomitans-derived EVs on oral cancer in comparison with other periodontopathogens. Our findings revealed a potential antitumorigenic effect of these EVs on metastatic OSCC cells, which warrants further in vivo investigations.

Parvimonas micra Bacteremia in the Setting of a Hepatic Abscess: A Case Report.

Parvimonas micra is a Gram-positive anaerobic coccus that typically colonizes the oral cavity and gastrointestinal tract in humans. Though P. micra is typically associated with periodontal abscesses, it can also be an unlikely cause of bacteremia. Here, we report a case of P. micra bacteremia in the setting of a hepatic abscess. Antibiotic treatment of the bacteremia was initiated, and the entry source of the infection was investigated using various imaging techniques in the inpatient setting. A hepatic abscess was suspected to be the origin of infection for the P. micra bacteremia. Successful antibiotic treatment was confirmed by negative repeat blood cultures and an improvement in the patient's symptoms and clinical picture.

Parvimonas micra: A Rare Cause of Pleural Empyema With COVID-19 Co-infection.

Parvimonas micra, an oral anaerobe and a known gastrointestinal microbiota, has also been found to be enriched in mucosal tissues of the colon. Our patient presented with chest pain, productive cough, and hypoxia. He was diagnosed with COVID-19 pneumonia with a suspected superimposed bacterial infection. After the initiation of treatment, the patient developed a right hydropneumothorax/loculated pleural effusion on X-ray. Bedside drainage was done, and cross-sectional imaging showed findings of pleural empyema. Cultures obtained after bedside drainage grew P. micra. The patient underwent right posterolateral open thoracotomy, total lung decortication, wedge resection, pneumonolysis, and mechanical pleurodesis. Antimicrobial therapy was adjusted based on culture sensitivities and infectious disease evaluation. Adequate drainage and source control were achieved, COVID-19 infection was resolved, and the patient was discharged on oral antibiotics. This case report highlights a rare and interesting case of pleural empyema caused by a superimposed bacterial infection with P. micra in a patient with COVID-19 pneumonia.

Sternoclavicular Septic Arthritis Caused by Parvimonas micra and Fusobacterium nucleatum Infection with Intra-articular Corticosteroid Administration.

Sternoclavicular septic arthritis is a rare form of septic arthritis that can lead to fatal complications, such as abscess formation and mediastinitis, in the absence of prompt diagnosis and appropriate treatment. A man in his 40s presented with pain in the right sternoclavicular joint area, and after a joint injection of steroids was administered, he was diagnosed with septic sternoclavicular arthritis caused by Parvimonas micra and Fusobacterium nucleatum. Gram staining of a specimen obtained from the abscess formation area led to early suspicion of anaerobic infection, and appropriate antibiotics were administered.

A pulmonary abscess caused by Porphyromonas endodontalis infection:A case report and literature review.

Porphyromonas endodontalis is an oral anaerobic bacterium associated with periodontitis but seldomly been detected in other diseases. Only one case of respiratory disease caused by Porphyromonas endodontalis, pyopneumothorax, has been reported so far. A 53-year-old man with refractory periodontitis was admitted due to an indeterminate lung space-occupying lesion. Following mNGS analysis of the liquefaction necrotic area and solid component of the lesion through biopsy, Porphyromonas endodontalis and Parvimonas micra were detected. Therefore, the patient was diagnosed with an aspiration lung abscess and discharged after receiving effective antibacterial treatment. The Chest computed tomography (CT) scan revealed a remarkable improvement during outpatient follow-up. In this study, we applied mNGS to diagnose a case of lung abscess attributed to an uncommon bacterium successfully, suggesting that when patients complicated with periodontal diseases and clinical respiratory symptoms, the possibility of inhalation disease caused by oral pathogens should be considered.

Employing Cloning-Independent Mutagenesis of Parvimonas micra for the Study of Cell Wall Biogenesis.

The cell wall plays an important structural role for bacteria and is intimately tied to a variety of critical processes ranging from growth and differentiation to pathogenesis. Our understanding of cell wall biogenesis is primarily derived from a relatively small number of heavily studied model organisms. Consequently, these processes can only be inferred for the vast majority of prokaryotes, especially among groups of uncharacterized and/or genetically intractable organisms. Recently, we developed the first tractable genetic system for Parvimonas micra, which is a ubiquitous Gram-positive pathobiont of the human microbiome involved in numerous types of inflammatory infections as well as a variety of malignant tumors. P. micra is also the first, and currently only, member of the entire Tissierellia class of the Bacillota phylum in which targeted genetic manipulation has been demonstrated. Thus, it is now possible to study cell wall biogenesis mechanisms within a member of the Tissierellia, which may also reveal novel aspects of P. micra pathobiology. Herein, we describe a procedure for cloning-independent genetic manipulation of P. micra, including allelic replacement mutagenesis and genetic complementation. The described techniques are also similarly applicable for the study of other aspects of P. micra pathobiology and physiology.

Pyogenic Spondylitis Caused by Parvimonas micra: A Case Report.

Parvimonas micra (P. micra) is a gram-positive anaerobic coccus endemic to the oral cavity and intestinal tract. We report a case of pyogenic spondylitis caused by P. micra and summarize the clinical features of previous case reports. An 81-year-old man with a history of lumbar vertebral compression fracture two years previously presented to the emergency department with low back pain. He was clinically diagnosed with pyogenic spondylitis due to difficulty in moving his body, spinal tapping pain, and signs of inflammation. He was hospitalized, and aerobic and anaerobic blood culture samples were collected, but the results were negative. Computed tomography and magnetic resonance imaging revealed inflammation in the second and third lumbar vertebrae and L2/3 and L3/4 intervertebral discs, and culture of the infected disc biopsy showed P. micra growth. After six weeks of treatment with ampicillin-sulbactam and ampicillin, the patient's symptoms improved, and he was discharged. During hospitalization, he was diagnosed with periodontitis and type 2 diabetes; his dentures were adjusted, and he was started on an oral hypoglycemic agent. Pyogenic spondylitis caused by P. micra tends to be associated with oral infections. This case illustrates the importance of appropriate detection and treatment of the source of infection to prevent recurrence.

Severe pneumonia with empyema caused by Parvimonas micra and Streptococcus constellatus co-infection: a case report.

Empyema is a common complication of pneumonia, caused by the accumulation of purulent exudate due to pathogenic bacteria invading the pleural cavity. Parvimonas micra and Streptococcus constellatus are pathogens that rarely cause pneumonia with empyema. Herein, a case of severe empyema caused by these two pathogens, confirmed by metagenomic next-generation sequencing (mNGS) of pleural effusion cultures, is reported. A male Chinese patient in his late sixties presented with wheezing, cough, sputum expectoration, and fever. Blood and sputum cultures were negative for pathogens, but the pleural effusion culture was positive for S. constellatus, and was also found to contain P. micra, confirmed by mNGS. The patient's symptoms improved after treatment with cefoperazone/sulbactam and moxifloxacin. Pneumonia caused by P. micra and S. constellatus is rare; however, coinfection with these pathogens may cause severe pneumonia, with or without empyema.

A rare anaerobic cause of vertebral osteomyelitis and psoas abscess: A case study.

Parvimonas micra is an obligate anaerobe that forms part of the normal gastrointestinal flora. The advent of matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF) and 16s ribosomal RNA gene sequencing has led to increased detection of many rare anaerobic isolates, including Parvimonas micra. Typical risk factors for Parvimonas micra bacteremia include dental procedures or spinal instrumentation. Here, we report a case of Parvimonas micra spondylodiscitis and psoas abscess in a patient with no obvious antecedent risk factors and explore the challenges in isolation of the organism from tissue samples.

Parvimonas micra, an oral pathobiont associated with colorectal cancer, epigenetically reprograms human colonocytes.

Recently, an intestinal dysbiotic microbiota with enrichment in oral cavity bacteria has been described in colorectal cancer (CRC) patients. Here, we characterize and investigate one of these oral pathobionts, the Gram-positive anaerobic coccus Parvimonas micra. We identified two phylotypes (A and B) exhibiting different phenotypes and adhesion capabilities. We observed a strong association of phylotype A with CRC, with its higher abundance in feces and in tumoral tissue compared with the normal homologous colonic mucosa, which was associated with a distinct methylation status of patients. By developing an in vitro hypoxic co-culture system of human primary colonic cells with anaerobic bacteria, we show that P. micra phylotype A alters the DNA methylation profile promoters of key tumor-suppressor genes, oncogenes, and genes involved in epithelial-mesenchymal transition. In colonic mucosa of CRC patients carrying P. micra phylotype A, we found similar DNA methylation alterations, together with significant enrichment of differentially expressed genes in pathways involved in inflammation, cell adhesion, and regulation of actin cytoskeleton, providing evidence of P. micra's possible role in the carcinogenic process.

Parvimonas micra can translocate from the subgingival sulcus of the human oral cavity to colorectal adenocarcinoma.

Oral and intestinal samples from a cohort of 93 colorectal cancer (CRC) patients and 30 healthy controls (non-CRC) were collected for microbiome analysis. Saliva (28 non-CRC and 94 CRC), feces (30 non-CRC and 97 CRC), subgingival fluid (20 CRC), and tumor tissue samples (20 CRC) were used for 16S metabarcoding and/or RNA sequencing (RNAseq) approaches. A differential analysis of the abundance, performed with the ANCOM-BC package, adjusting the P-values by the Holm-Bonferroni method, revealed that Parvimonas was significantly over-represented in feces from CRC patients (P-value < 0.001) compared to healthy controls. A total of 11 Parvimonas micra isolates were obtained from the oral cavity and adenocarcinoma of CRC patients. Genome analysis identified a pair of isolates from the same patient that shared 99.2% identity, demonstrating that P. micra can translocate from the subgingival cavity to the gut. The data suggest that P. micra could migrate in a synergistic consortium with other periodontal bacteria. Metatranscriptomics confirmed that oral bacteria were more active in tumor than in non-neoplastic tissues. We suggest that P. micra could be considered as a CRC biomarker detected in non-invasive samples such as feces.

Empyema and bacteremia caused by Parvimonas micra: A case report.

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.

Septic Embolism Associated With Periodontal Disease: A Case Report.

Parvimonas micra and Provetella oralis are two commensal anaerobic bacteria of the human oral cavity. Anaerobic bacteria infections are uncommon and require a high index of suspicion and a quick start of appropriate treatment. We present a patient with multifocal infiltrates compatible with septic embolism (lung, liver, and spleen emboli) and polymicrobial bacteremia with Parvimonas micra and Provetella oralis. Periodontal disease appears to be the main cause of this disseminated infection.

Age-Related Subgingival Colonization of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Parvimonas micra-A Pragmatic Microbiological Retrospective Report.

The aim of this study was to compare data about the prevalence and proportions of the bacterial species Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Parvimonas micra in periodontitis pocket samples collected from young, <35 years, and old, >35-year-old patients, YP and OP, respectively. The results from the analyses of a total of 3447 subgingival plaque samples analyzed for clinical diagnosis purposes by cultivation regarding the proportions of these species were collected from a database and elucidated. The prevalence of A. actinomycetemcomitans was found to be more than twice as high (OR = 2.96, 95% CI; 2.50-3.50) in samples from the younger (42.2%) than the older group (20.4%) (p < 0.001). The prevalence of P. micra was significantly lower in samples from the younger age group (OR = 0.43, 95%) (p < 0.001), whereas P. gingivalis was similarly distributed (OR = 0.78, 95%) in the two age groups (p = 0.006). A similar pattern was noticed for A. actinomycetemcomitans and P. gingivalis when high proportions (>50%) of the samples of these bacterial species were elucidated. In contrast, the proportion of samples containing >50% with P. micra was lower compared with the two other bacterial species. Furthermore, it was noted that the proportion of samples from old patients containing A. actinomycetemcomitans in combination with P. micra was almost three times higher than in samples when P. micra was replaced by P. gingivalis. In conclusion, A.actinomycetemcomitans showed an increased presence and proportion in samples from young patients compared with the old patients, while P. gingivalis was similarly distributed in the two age groups. P. micra showed an increased presence and proportion in samples from old patients compared with the young patients.