Clinical Characteristics of Chronic Lung Abscess Associated with Parvimonas micra Diagnosed Using Metagenomic Next-Generation Sequencing

Abstract

Parvimonas micra (P. micra) is a Gram-positive anaerobic bacterium distributed in the oral cavity, with a potential to become pathogenic causing lung abscess. Due to the lack of specificity of symptoms and the difficulty in culture, the diagnosis of lung abscess associated with P. micra is delayed. It is essential to elucidate the clinical characteristics of lung abscess associated with P. micra. Methods: From January 2019 to July 2020, five patients with chronic lung abscess associated with P. micra diagnosed by pathological biopsy and metagenomic next-generation sequencing (mNGS) were analyzed in this retrospective study. Results: Among the five patients, four had a history of smoking, three had periodontitis, and two had a history of drinking. The average course of the disease was 6.5 months. Highdensity flake-like or mass shadows with irregular boundaries were observed in the chest computed tomography (CT) images of the five patients, and liquefactive necrosis was detected in the middle of the lesions; however, no gas-liquid plane or cavity was noted, making it difficult to distinguish a lung cancer. The pathological biopsy of the five patients showed chronic inflammation of lung tissue, and P. micra was detected by mNGS in the biopsy or bronchoalveolar lavage fluid samples. Two patients were treated with amoxicillinclavulanate, two had metronidazole, and one had moxifloxacin. Among them, four recovered after receiving antibiotic treatment, and the remaining one underwent surgical resection due to poor antibiotic treatment effect. Conclusion: Chronic lung abscess associated with P. micra, common in elderly male smokers with poor oral hygiene, is often diagnosed in a delayed manner and misdiagnosed as lung cancer. The mNGS technology is beneficial to the rapid determination of P. micra.

Furious lung abscess due to Parvimonas micra

“…Purulent diseases are typical pathologies of P. micra infection, and patients with lung abscess due to P. micra were reported in elderly men with poor oral hygiene who smoke and drink heavily. 1,2 However, the present patient had no such risk factors. The patient did not respond to the antibiotics given and only improved after the surgical intervention indicating the high virulence of this bacteria.…”

Case report: Successful management of Parvimonas micra pneumonia mimicking hematogenous Staphylococcus aureus pneumonia

“…It also affects oral microbiota composition ( 21 ). The level of P. micra and other bacteria in the oral cavity is higher in smokers than in non-smokers ( 8 ). We also noted poor hygiene with suspected periodontitis and decreased α diversity in the oral microbiome of our patient, accompanied by similar copies of P. micra between oral wash and BALF samples.…”

“…The previous studies have suggested that the durations of antibiotic therapy for P. micra pneumonia are highly variable ( 8 ) and there is little evidence of hematogenous P. micra pneumonia. Watanabe et al ( 7 ) reported a case of P. micra -related hematogenous lung abscess in which chest CT showed that the lung lesions resolved after 1 month of antibiotic treatment with ampicillin sulbactam.…”

“…Because it is anaerobic, P. micra is not a dominant bacterium in aerobic environments, including the lung. Although there are some reports of P. micra pneumonia due to aspiration, hematogenous P. micra pneumonia is rare (7)(8)(9). Moreover, to the best of our knowledge, there are no reports of P. micrarelated pneumonia induced by bloodstream infection without a definitive, remote pathogenic source.…”

The Value of Metagenomic Next -Generation Sequence In Acquired Immunodeficiency Syndrome With Opportunistic Infections

“…With the fast development of molecular biology, metagenomic next-generation sequence (mNGS),a novel and promising approach, has emerged as pan-pathogen assays for infectious diseases diagnosis, especially for the detection of atypical, rare, or slow-growing microbes [9][10][11].To date, many studies have addressed the value of mNGS in detected the causative pathogens and guided targeted antimicrobial therapy more quikly [12][13][14][15][16][17].…”