Metagenomic Next-Generation Sequencing Assists in the Diagnosis of Gardnerella vaginalis in Males with Pleural Effusion and Lung Infection: A Case Report and Literature Review

Figures & data

Figure 1 Comparison of cross-sectional chest CT images obtained from the patient at different time points. A1-4 October 5th, 2020: The day of admission; B1-4 Eighth day after admission on October 13th, 2020; C1-4 October 22nd, 2020 The day of discharge; D1-4 November 14th, 2020 20 days after discharge; E1-4 February 6th, 2021 Nearly 4 months after discharge.

Table 1 Sequencing Results of mNGS from the Patient’s Alveolar Lavage Fluid Showing Detected Bacteria and Suspected Pathogens

		Species			Genera
		Designation	Sequence Number	Relative Abundance	Designation	Sequence Number
Detected bacteria	G^a	Gardnerella vaginalis	10,876	20.37%	Gardnerella	10,876
	G+	Corynebacterium urealyticum	3711	6.95%	Corynebacterium	6529
Suspected pathogens	G+	Atopobium vaginae	1128		Atopobium	1188
	G+	Lactobacillus iners	1102		Lactobacillus	1144
	G-	Prevotella amnii	1722		Prevotella	2970
	Mycobacterium	Mycobacterium chelonae	14		Mycobacterium	92

Note: ^aG. vaginalis is a Gram-variable staining bacterium that is typically a small non-spore forming coccobacillus.

Table 2 Reports of Lung Infections Caused by G. vaginalis

Study	Report Year	Gender	Age	Presentation	Medical History and Possible Risk Factors	Diagnostic Method	Management
Legrand et al^Citation15	1989	Male	41	Pulmonary abscess and empyema	Alcohol abuser	Material obtained from the respiratory tract was classified by the system of Murray and Washington (10), and class 5 specimens were inoculated on blood agar (CO2), Columbia agar (CO2 and anaerobic), and modified Casman agar (Columbia agar with peptone, nalidixic acid, and colimycin) (anaer obic). Specimens from pleural spaces were cultured.	Ceftazidime (2 g iv twice a day) for 12 days→Penicillin (20 x 106 U/day) for 2 days→Penicillin was replaced with minocycline (200 mg twice a day) and metronidazole (500 mg three times a day)→clindamycin, ampicillin and minocycline therapy→chloramphenicol was injected in the pleural space.
Calvert et al^Citation18	2005	Male	50	Multiple abscesses	Smoked 20 cigarettes a day for 30 years and drank 25 units of alcohol a week.	Right perinephric and pleural aspirates culture	IV high dose benzylpenicillin, cefuroxime and metronidazole for 41 days→oral metronidazole 400 mg twice daily and amoxycillin 500 mg three times a day
Bittar et al^Citation25	2019	Male	20	Pulmonary infection	Previously healthy	Respiratory secretions for culture by mini bronchoalveolar lavage	Intravenous Vancomycin and Piperacillin/Tazobactam for 11 days→ampicillin-sul bactam for 4 days→Vancomycin and Cefepime metronidazole treatment for 4 days→ceftriaxone and metronidazole
MurrayL^Citation8	2019	Female	20	Pyohydropneumothorax and associated respiratory sepsis	14 days post partum	Isolation from pleural fluid	Piperacillin-Tazobactam 4.5g TDS and Vancomycin 15mg/Kg (1g) BD→clindamycin 800mg IV TDS→ a video-assisted thoracoscopic surgery
Tamlihat^Citation29	2020	Male	45	VAP	Cardiorespiratory arrest; post-anoxic encephalopathy; inhalation pneumonia.	Protected distal bronchial sampling	Amoxicillin-clavulanic acid; cefotaxime + metronidazole

Figure 2 A flow chart describing the patient diagnosis process.

Legrand JC, Alewaeters A, Leenaerts L, et al. Gardnerella vaginalis bacteremia from pulmonary abscess in a male alcohol abuser. J Clin Microbiol. 1989;27(5):1132–1134. doi:10.1128/jcm.27.5.1132-1134.19892787333

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Murray L, Halpin J, Casserly B, et al. A pyo-hydropneumothorax with sepsis, secondary to Gardnerella vaginalis infection in a post-partum female. Respir Med Case Rep. 2019;26:189–192. doi:10.1016/j.rmcr.2019.01.00730705817

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Tamlihat YA, Augereau PF, Lardillon G, et al. Gardnerella vaginalis is a rare cause of ventilator-associated pneumonia: a case report and literature review. J Med Cases. 2021;12(4):134–137. doi:10.14740/jmc364534434445

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