{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T08:47:40Z","timestamp":1782377260556,"version":"3.54.5"},"reference-count":36,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2026,6,24]],"date-time":"2026-06-24T00:00:00Z","timestamp":1782259200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Infectious Disease Reports"],"abstract":"<jats:p>Background: Secondary bacterial infections are increasingly recognized after coronavirus disease 2019 (COVID-19); however, bacterial abscess formation remains uncommon, and the simultaneous occurrence of brain and lung abscesses has not been previously reported. We report a rare case of Streptococcus intermedius infection presenting with multiple brain microabscesses and a lung abscess following COVID-19. Case Presentation: A 75-year-old man with no significant medical history except cholelithiasis experienced persistent fever following a diagnosis of COVID-19 and subsequently developed impaired consciousness 17 days later. Because bacterial meningitis was suspected, he was admitted to a neurology-specialized hospital on the same day. Brain MRI revealed more than 80 small enhancing lesions scattered throughout the brain parenchyma, consistent with multiple microabscesses. Chest CT demonstrated a mass-like lesion in the left lower lobe. Although cerebrospinal fluid cultures were negative, blood cultures obtained on admission yielded S. intermedius. Further investigation of the source of infection revealed moderate periodontitis, suggesting the oral cavity as the probable portal of entry. The patient was treated with intravenous antibiotics for eight weeks based on antimicrobial susceptibility testing, resulting in near-complete resolution of the lesions. Conclusions: Although a causal relationship between COVID-19 and abscess formation cannot be established, COVID-19-associated immune and mucosal barrier dysfunction may have contributed to the progression and dissemination of infection in this patient. Clinicians should be aware of the possibility of severe bacterial superinfection when fever or respiratory symptoms related to COVID-19 persist, even in patients without overt immunocompromise, particularly in those with pre-existing oral infections.<\/jats:p>","DOI":"10.3390\/idr18040064","type":"journal-article","created":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T05:48:16Z","timestamp":1782366496000},"page":"64","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Multiple Brain Microabscesses and a Lung Abscess Caused by Streptococcus intermedius Following COVID-19: A Case Report and Literature Review"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0009-0000-2740-9007","authenticated-orcid":false,"given":"Ryoma","family":"Takeda","sequence":"first","affiliation":[{"name":"Department of Pharmacy, Nakamura Memorial Hospital, South 1, West 14, Chuo-ku, Sapporo 060-8570, Hokkaido, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-1464-2592","authenticated-orcid":false,"given":"Kazunori","family":"Yamada","sequence":"additional","affiliation":[{"name":"Department of Pharmacy, Nakamura Memorial Hospital, South 1, West 14, Chuo-ku, Sapporo 060-8570, Hokkaido, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Takenori","family":"Abe","sequence":"additional","affiliation":[{"name":"Department of Neurology, Nakamura Memorial Hospital, South 1, West 14, Chuo-ku, Sapporo 060-8570, Hokkaido, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2689-5338","authenticated-orcid":false,"given":"Tomoyuki","family":"Ishigo","sequence":"additional","affiliation":[{"name":"Department of Pharmacy, Sapporo Medical University Hospital, South 1, West 16, Chuo-ku, Sapporo 060-8543, Hokkaido, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hirohiko","family":"Nakamura","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Nakamura Memorial Hospital, South 1, West 14, Chuo-ku, Sapporo 060-8570, Hokkaido, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"107078","DOI":"10.1016\/j.ijid.2024.107078","article-title":"Prevalence, risk factors, and outcomes of secondary infections among hospitalized patients with COVID-19 or post-COVID-19 conditions in Victoria, 2020\u20132023","volume":"145","author":"Murray","year":"2024","journal-title":"Int. J. Infect. Dis."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"700","DOI":"10.1016\/j.jiac.2023.02.005","article-title":"Lung abscess as a secondary infection of COVID-19: A case report and literature review","volume":"29","author":"Umamoto","year":"2023","journal-title":"J. Infect. Chemother."},{"key":"ref_3","first-page":"e36258","article-title":"Bacterial brain abscess and life-threatening intracranial hypertension requiring emergent decompressive craniectomy after SARS-CoV-2 infection in a healthy adolescent","volume":"15","author":"Kunapaisal","year":"2023","journal-title":"Cureus"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"623","DOI":"10.1016\/j.jinf.2020.03.011","article-title":"Microbial aetiology of brain abscess in a UK cohort: Prominent role of Streptococcus intermedius","volume":"80","author":"Darlow","year":"2020","journal-title":"J. Infect."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"547","DOI":"10.1093\/ajcp\/104.5.547","article-title":"Streptococcus anginosus, Streptococcus constellatus and Streptococcus intermedius: Clinical relevance, hemolytic and serologic characteristics","volume":"104","author":"Jacobs","year":"1995","journal-title":"Am. J. Clin. Pathol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"68","DOI":"10.3904\/kjim.2022.084","article-title":"Clinical outcomes of and risk factors for secondary infection in patients with severe COVID-19: A multicenter cohort study in South Korea","volume":"38","author":"Na","year":"2023","journal-title":"Korean J. Intern. Med."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"e156","DOI":"10.1017\/ash.2023.425","article-title":"Characteristics and risk factors of secondary bacterial infections in COVID-19 patients","volume":"3","author":"Wu","year":"2023","journal-title":"Antimicrob. Steward. Healthc. Epidemiol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2107","DOI":"10.1016\/j.csbj.2025.05.033","article-title":"Dual threat: Susceptibility mechanisms and treatment strategies for COVID-19 and bacterial co-infections","volume":"27","author":"Chen","year":"2025","journal-title":"Comput. Struct. Biotechnol. J."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Smail, S.W., Albarzinji, N., Salih, R.H., Taha, K.O., Hirmiz, S.M., Ismael, H.M., Noori, M.F., Azeez, S.S., and Janson, C. (2025). Microbiome dysbiosis in SARS-CoV-2 infection: Implication for pathophysiology and management strategies of COVID-19. Front. Cell. Infect. Microbiol., 15.","DOI":"10.3389\/fcimb.2025.1537456"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"905","DOI":"10.1007\/s10096-020-04138-6","article-title":"COVID-19: Angiotensin-converting enzyme 2 (ACE2) expression and tissue susceptibility to SARS-CoV-2 infection","volume":"40","author":"Beyerstedt","year":"2021","journal-title":"Eur. J. Clin. Microbiol. Infect. Dis."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"e9610","DOI":"10.15252\/msb.20209610","article-title":"The protein expression profile of ACE2 in human tissues","volume":"16","author":"Hikmet","year":"2020","journal-title":"Mol. Syst. Biol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1417","DOI":"10.1016\/S0140-6736(20)30937-5","article-title":"Endothelial cell infection and endotheliitis in COVID-19","volume":"395","author":"Varga","year":"2020","journal-title":"Lancet"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"318","DOI":"10.1007\/s11033-024-09279-x","article-title":"COVID-19 and the brain: Understanding the pathogenesis and consequences of neurological damage","volume":"51","author":"Maliha","year":"2024","journal-title":"Mol. Biol. Rep."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Shehata, G.A., Lord, K.C., Grudzinski, M.C., Elsayed, M., Abdelnaby, R., and Elshabrawy, H.A. (2021). Neurological complications of COVID-19: Underlying mechanisms and management. Int. J. Mol. Sci., 22.","DOI":"10.3390\/ijms22084081"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"32","DOI":"10.5692\/clinicalneurol.cn-002013","article-title":"Posterior reversible encephalopathy syndrome after COVID-19 in a patient with chronic renal failure","volume":"65","author":"Kawachi","year":"2025","journal-title":"Rinsho Shinkeigaku"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1186\/s12974-021-02339-0","article-title":"Cerebrospinal fluid findings in COVID-19: A multicenter study of 150 lumbar punctures in 127 patients","volume":"19","author":"Jarius","year":"2022","journal-title":"J. Neuroinflamm."},{"key":"ref_17","first-page":"100776","article-title":"Delayed pulmonary abscess following COVID-19 pneumonia: A case report","volume":"78","author":"Gallais","year":"2020","journal-title":"Respir. Med. Res."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Okui, T., Matsuda, Y., Karino, M., Hideshima, K., and Kanno, T. (2021). Oral mucosa could be an infectious target of SARS-CoV-2. Healthcare, 9.","DOI":"10.3390\/healthcare9081068"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"CASE22423","DOI":"10.3171\/CASE22423","article-title":"Sinusitis complicated by intracranial abscess in 3 patients with coronavirus disease 2019: Illustrative cases","volume":"5","author":"Griffin","year":"2023","journal-title":"J. Neurosurg. Case Lessons"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"CASE22127","DOI":"10.3171\/CASE22127","article-title":"Intracranial complications of hypercoagulability and superinfection in the setting of COVID-19: Illustrative cases","volume":"3","author":"Blitz","year":"2022","journal-title":"J. Neurosurg. Case Lessons"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"e6763","DOI":"10.1002\/ccr3.6763","article-title":"Lung abscess due to Streptococcus intermedius associated with SARS-CoV-2 infection in pregnancy","volume":"11","author":"Bueno","year":"2023","journal-title":"Clin. Case Rep."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"195","DOI":"10.1080\/08998280.2011.11928714","article-title":"Splenic abscess and multiple brain abscesses caused by Streptococcus intermedius in a young healthy man","volume":"24","author":"Maliyil","year":"2011","journal-title":"Bayl. Univ. Med. Cent. Proc."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"e6813","DOI":"10.1002\/ccr3.6813","article-title":"A case report of multiple abscesses caused by Streptococcus intermedius","volume":"11","author":"Reyes","year":"2023","journal-title":"Clin. Case Rep."},{"key":"ref_24","first-page":"e32797","article-title":"Multifocal brain abscesses due to Streptococcus intermedius","volume":"14","author":"Isern","year":"2022","journal-title":"Cureus"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"4160","DOI":"10.1128\/JCM.01296-12","article-title":"Identification of Streptococcus intermedius central nervous system infection by use of PCR and electrospray ionization mass spectrometry","volume":"50","author":"Bhatia","year":"2012","journal-title":"J. Clin. Microbiol."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Fransson, M., Helld\u00e9n, A., Balkhed, \u00c5.\u00d6., Dernroth, D.N., Ha, M., Haglund, M., Milos, P., Hanberger, H., and K\u00e5gedal, B. (2021). Case report: Subtherapeutic vancomycin and meropenem concentrations due to augmented renal clearance in a patient with intracranial infection caused by Streptococcus intermedius. Front. Pharmacol., 12.","DOI":"10.3389\/fphar.2021.728075"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1292","DOI":"10.1001\/archneurol.2009.204","article-title":"Multiple brain abscesses associated with tongue piercing","volume":"66","author":"Herskovitz","year":"2009","journal-title":"Arch. Neurol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"23247096241239572","DOI":"10.1177\/23247096241239572","article-title":"Esophageal perforation presenting initially as multiple brain abscesses secondary to Streptococcus intermedius","volume":"12","author":"Swied","year":"2024","journal-title":"J. Investig. Med. High Impact Case Rep."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"CASE22458","DOI":"10.3171\/CASE22458","article-title":"Concomitant brain abscess and spinal cord abscess in an immunocompetent teenage male: Illustrative case","volume":"5","author":"Virtanen","year":"2023","journal-title":"J. Neurosurg. Case Lessons"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1177\/1941874420971154","article-title":"Neurotoxic effects of ammonia in a patient with ornithine transcarbamylase deficiency and bilateral brain abscesses: Case report","volume":"11","author":"Sayyahmelli","year":"2021","journal-title":"Neurohospitalist"},{"key":"ref_31","first-page":"1199","article-title":"A case of culture-negative brain abscess caused by Streptococcus intermedius infection diagnosed by broad-range PCR of 16S ribosomal RNA","volume":"65","author":"Ohara","year":"2013","journal-title":"Brain Nerve"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Yao, L., Chen, S., Yu, Z., and Yu, T. (2022). Multifocal brain abscesses caused by invasive Streptococcus intermedius: A case report. Front. Neurol., 13.","DOI":"10.3389\/fneur.2022.893627"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"972","DOI":"10.3171\/jns.1983.59.6.0972","article-title":"Clinical stages of human brain abscesses on serial CT","volume":"59","author":"Britt","year":"1983","journal-title":"J. Neurosurg."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"654","DOI":"10.2169\/internalmedicine.40.654","article-title":"Bacillus cereus brain abscesses occurring in a severely neutropenic patient: Successful treatment with antimicrobial agents, granulocyte colony-stimulating factor and surgical drainage","volume":"40","author":"Sakai","year":"2001","journal-title":"Intern. Med."},{"key":"ref_35","first-page":"1597","article-title":"Disseminated aspergillosis involving the brain: Distribution and imaging characteristics","volume":"20","author":"DeLone","year":"1999","journal-title":"AJNR Am. J. Neuroradiol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"6803510","DOI":"10.1155\/2021\/6803510","article-title":"Effect of ORF7 of SARS-CoV-2 on the chemotaxis of monocytes and neutrophils in vitro","volume":"2021","author":"Wang","year":"2021","journal-title":"Dis. Markers"}],"container-title":["Infectious Disease Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2036-7449\/18\/4\/64\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T08:04:23Z","timestamp":1782374663000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2036-7449\/18\/4\/64"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,24]]},"references-count":36,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2026,8]]}},"alternative-id":["idr18040064"],"URL":"https:\/\/doi.org\/10.3390\/idr18040064","relation":{},"ISSN":["2036-7449"],"issn-type":[{"value":"2036-7449","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,24]]}}}