Microbial co-infections in COVID-19: Associated microbiota and underlying mechanisms of pathogenesis

• Published in: Microbial pathogenesis 2021-07, Vol.156, p.104941-104941, Article 104941
• Main Authors: Hoque, M. Nazmul, Akter, Salma, Mishu, Israt Dilruba, Islam, M. Rafiul, Rahman, M. Shaminur, Akhter, Masuda, Islam, Israt, Hasan, Mehedi Mahmudul, Rahaman, Md. Mizanur, Sultana, Munawar, Islam, Tofazzal, Hossain, M. Anwar
• Format: Article
• Language: English
• Subjects: Coinfection; Communicable Diseases; COVID-19; Humans; Microbial co-infections; Microbiota; Molecular pathogenesis; SARS-CoV-2
• ISSN: 0882-4010; 1096-1208; 1096-1208
• DOI: 10.1016/j.micpath.2021.104941

The novel coronavirus infectious disease-2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has traumatized the whole world with the ongoing devastating pandemic. A plethora of microbial domains including viruses (other than SARS-CoV-2), bacteria, archaea and fungi have evolved together, and interact in complex molecular pathogenesis along with SARS-CoV-2. However, the involvement of other microbial co-pathogens and underlying molecular mechanisms leading to extortionate ailment in critically ill COVID-19 patients has yet not been extensively reviewed. Although, the incidence of co-infections could be up to 94.2% in laboratory-confirmed COVID-19 cases, the fate of co-infections among SARS-CoV-2 infected hosts often depends on the balance between the host's protective immunity and immunopathology. Predominantly identified co-pathogens of SARS-CoV-2 are bacteria such as Streptococcus pneumoniae, Staphylococcus aureus, Klebsiella pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Acinetobacter baumannii, Legionella pneumophila and Clamydia pneumoniae followed by viruses including influenza, coronavirus, rhinovirus/enterovirus, parainfluenza, metapneumovirus, influenza B virus, and human immunodeficiency virus. The cross-talk between co-pathogens (especially lung microbiomes), SARS-CoV-2 and host is an important factor that ultimately increases the difficulty of diagnosis, treatment, and prognosis of COVID-19. Simultaneously, co-infecting microbiotas may use new strategies to escape host defense mechanisms by altering both innate and adaptive immune responses to further aggravate SARS-CoV-2 pathogenesis. Better understanding of co-infections in COVID-19 is critical for the effective patient management, treatment and containment of SARS-CoV-2. This review therefore necessitates the comprehensive investigation of commonly reported microbial co-pathogens amid COVID-19, their transmission pattern along with the possible mechanism of co-infections and outcomes. Thus, identifying the possible co-pathogens and their underlying molecular mechanisms during SARS-CoV-2 pathogenesis may shed light in developing diagnostics, appropriate curative and preventive interventions for suspected SARS-CoV-2 respiratory infections in the current pandemic.