Gemella morbillorum- and Capnocytophaga sp.-Related Mycotic Thoracic Aortic Aneurysm and Mediastinal Abscess: An Unusual Case Report, a Treatment Challenge, and a Review of Literature

Abstract

A thoracic mycotic aortic aneurysm is an uncommon entity that can complicate mediastinal abscesses. Gemella morbillorum and Capnocytophaga sp. are oral bacteria that are very rarely encountered in this setting, especially when occurring together and with other organisms, posing a difficult treatment challenge per the available guidelines and sensitivities. We present in detail this interesting case of a multi-organism mediastinal abscess and thoracic mycotic aortic aneurysm after a previous esophagogastroduodenoscopic procedure in a 51-year-old female with known achalasia who presented with upper abdominal pain, including a successful surgical and antibiotic treatment regimen and a literature review of the involved topics.

Gemella morbillorum as the Culprit Organism of Post-Colonoscopy Necrotizing Perineal Soft Tissue Infection in a Diabetic Patient With Crohn’s Disease

“…Most isolated G. morbillorum species in the literature were generally sensitive to most antibiotics, but metronidazole [12][13][14], in line with the strain isolated in our patient. At present, penicillin G and ampicillin are considered of choice for extra- abdominal Gemella infections [19].…”

“…Human infections due to G. morbillorum are an uncommon occurrence, but they have been well described in the literature with certain predisposing factors [4][5][6][7]. The most reported infections were infective endocarditis, affecting both native and prosthetic valves, which were usually encountered in the setting of post-endoscopic G. morbillorum bacteremia, poor dental hygiene, various immunosuppression states (such as diabetes mellitus and steroids use), and intravenous drug use [4][5][6], pleural empyema, which was likely related to possible aspiration of oropharyngeal contents [7], septic arthritis [8], spondylodiscitis [9], brain abscess [10], retropharyngeal abscess [11], lung abscess [1], and mediastinitis with mediastinal abscess complicating mycotic thoracic aortic aneurysm [12]. Nevertheless, necrotizing soft tissue infections due to G. morbillorum are rather a rare entity [3,[13][14][15], as per our literature review of the available English medical literature; only five cases of soft tissue infections were identified where G. morbillorum being isolated as a causative pathogen [3,[13][14][15].…”

Bacterial pathogens in pediatric appendicitis: a comprehensive retrospective study

“…It has been first described in 1917 as Streptococcum morbillorum and is part of the normal flora of human oropharynx, genitourinary system, and gastrointestinal system ( Romero-Velez et al., 2020 ). There are case reports of G. morbillorum causing necrositing fasciitis of the torso, thoracic aortic aneurysm, and endocarditis ( Ural et al., 2014 ; Romero-Velez et al., 2020 ; Said and Tirthani, 2021 ). To our knowledge, our 7 patients of whom 3 suffered from complications, are the first appendicitis patients with G.morbillorum reported in literature.…”

Endobronchial Infection and Bacterial Lymphadenitis by Gemella morbillorum Leading to Airway Perforation and a Bronchopleural Fistula

“…It is often misidentified as a viridans group Streptococcus , one that shares similar morphology and virulence to that of the Gemella species [ 3 ]. Human infection is rare, although it may be provoked by the use of intravenous drugs, excessive alcohol intake, diabetes mellitus, or poor dentition [ 4 ] [ 5 ]. Pneumonia with sepsis and bacteremia has been reported despite evident clinical symptoms of aspiration in both adults [ 6 ] and children [ 7 ].…”

“…Likewise, Gemella spp. mediastinitis has been reported to be related to odontic infection with the extension of a pharyngeal abscess [ 9 , 10 ], bacterial translocation of a mycotic aortic aneurysm [ 4 ], blunt force trauma [ 5 ], and in association with esophageal adenocarcinoma [ 3 ].…”