Opportunistic infection
Opportunistic infection | |
---|---|
Chest X-ray of a patient who first had influenza and then developed Haemophilus influenzae pneumonia, presumably opportunistic | |
Specialty | Infectious diseases |
An opportunistic infection is an infection caused by pathogens (bacteria, fungi, parasites or viruses) that take advantage of an opportunity not normally available. These opportunities can stem from a variety of sources, such as a weakened immune system (as can occur in acquired immunodeficiency syndrome or when being treated with immunosuppressive drugs, as in cancer treatment),[1] an altered microbiome (such as a disruption in gut microbiota), or breached integumentary barriers (as in penetrating trauma). Many of these pathogens do not necessarily cause disease in a healthy host that has a non-compromised immune system, and can, in some cases, act as commensals until the balance of the immune system is disrupted.[2][3] Opportunistic infections can also be attributed to pathogens which cause mild illness in healthy individuals but lead to more serious illness when given the opportunity to take advantage of an immunocompromised host.[4]
Types of opportunistic infections
A wide variety of pathogens are involved in opportunistic infection and can cause a similarly wide range in pathologies. A partial list of opportunistic pathogens and their associated presentations includes:
Bacteria
- Clostridioides difficile (formerly known as Clostridium difficile) is a species of bacteria that is known to cause gastrointestinal infection and is typically associated with the hospital setting.[5][6]
- Legionella pneumophila is a bacterium that causes Legionnaire’s disease, a respiratory infection.[7][8]
- Mycobacterium avium complex (MAC) is a group of two bacteria, M. avium and M. intracellulare, that typically co-infect, leading to a lung infection called mycobacterium avium-intracellulare infection.[9][10]
- Mycobacterium tuberculosis is a species of bacteria that causes tuberculosis, a respiratory infection.[11]
- Pseudomonas aeruginosa is a bacterium that can cause respiratory infections. It is frequently associated with cystic fibrosis and hospital-acquired infections.[12]
- Salmonella is a genus of bacteria, known to cause gastrointestinal infections.[13]
- Staphylococcus aureus is a bacterium known to cause skin infections and sepsis, among other pathologies. Notably, S. aureus has evolved several drug-resistant strains, including MRSA.[14][15]
- Streptococcus pneumoniae is a bacterium that causes respiratory infections.[2]
- Streptococcus pyogenes (also known as group A Streptococcus) is a bacterium that can cause a variety of pathologies, including impetigo and strep throat, as well as other, more serious, illnesses.[16][17]
Fungi
- Aspergillus is a fungus, commonly associated with respiratory infection.[18][19]
- Candida albicans is a species of fungus that is associated with oral thrush and gastrointestinal infection.[20][21]
- Coccidioides immitis is a fungus known for causing coccidioidomycosis, more commonly known as Valley Fever.[22]
- Cryptococcus neoformans is a fungus that causes cryptococcosis, which can lead to pulmonary infection as well as nervous system infections, like meningitis.[23][24]
- Histoplasma capsulatum is a species of fungus known to cause histoplasmosis, which can present with an array of symptoms, but often involves respiratory infection.[25][26]
- Pseudogymnoascus destructans (formerly known as Geomyces destructans) is a fungus that causes white-nose syndrome in bats.[27]
- Microsporidia is a group of fungi that infect species across the animal kingdom, one species of which can cause microsporidiosis in immunocompromised human hosts.[28]
- Pneumocystis jirovecii (formerly known as Pneumocystis carinii) is a fungus that causes pneumocystis pneumonia, a respiratory infection.[29]
Parasites
- Cryptosporidium is a protozoan that infects the gastrointestinal tract.[30]
- Toxoplasma gondii is a protozoan, known for causing toxoplasmosis.[31][32]
Viruses
- Cytomegalovirus is a family of opportunistic viruses, most frequently associated with respiratory infection.[19][33]
- Human polyomavirus 2 (also known as JC virus) is known to cause progressive multifocal leukoencephalopathy (PML).[34][35]
- Human herpesvirus 8 (also known as Kaposi sarcoma-associated herpesvirus) is a virus associated with Kaposi sarcoma, a type of cancer.[36][37]
Causes
Immunodeficiency or immunosuppression are characterized by the absence of or disruption in components of the immune system, leading to lower-than-normal levels of immune function and immunity against pathogens.[1] They can be caused by a variety of factors, including:
- Malnutrition
- Fatigue
- Recurrent infections
- Immunosuppressing agents for organ transplant recipients
- Advanced HIV infection
- Chemotherapy for cancer
- Genetic predisposition
- Skin damage
- Antibiotic treatment leading to disruption of the physiological microbiome, thus allowing some microorganisms to outcompete others and become pathogenic (e.g. disruption of intestinal microbiota may lead to Clostridium difficile infection)
- Medical procedures
- Pregnancy
- Aging
- Leukopenia (i.e. neutropenia and lymphocytopenia)
- Burns
The lack of or the disruption of normal vaginal microbiota allows the proliferation of opportunistic microorganisms and will cause the opportunistic infection bacterial vaginosis.[38][39][40][41]
Opportunistic Infection and HIV/AIDS
HIV is a virus that targets T cells of the immune system and, as a result, HIV infection can lead to progressively worsening immunodeficiency, a condition ideal for the development of opportunistic infection.[42][43] Because of this, respiratory and central nervous system opportunistic infections, including tuberculosis and meningitis, respectively, are associated with later-stage HIV infection, as are numerous other infectious pathologies.[44][45] Kaposi’s sarcoma, a virally-associated cancer, has higher incidence rates in HIV-positive patients than in the general population.[46] As immune function declines and HIV-infection progresses to AIDS, individuals are at an increased risk of opportunistic infections that their immune systems are no longer capable of responding properly to. Because of this, opportunistic infections are a leading cause of HIV/AIDS-related deaths.[47]
Prevention
Since opportunistic infections can cause severe disease, much emphasis is placed on measures to prevent infection. Such a strategy usually includes restoration of the immune system as soon as possible, avoiding exposures to infectious agents, and using antimicrobial medications ("prophylactic medications") directed against specific infections.[48]
Restoration of immune system
- In patients with HIV, starting antiretroviral therapy is especially important for restoration of the immune system and reducing the incidence rate of opportunistic infections[49][50]
- In patients undergoing chemotherapy, completion of and recovery from treatment is the primary method for immune system restoration. In a select subset of high risk patients, granulocyte colony stimulating factors (G-CSF) can be used to aid immune system recovery.[51][52]
Avoidance of infectious exposure
The following may be avoided as a preventative measure to reduce risk of infection:
- Eating undercooked meat or eggs, unpasteurized dairy products or juices.
- Potential sources of tuberculosis (high risk healthcare facilities, regions with high rates of tuberculosis, patients with known tuberculosis).
- Any oral exposure to feces.[53]
- Contact with farm animals, especially those with diarrhea: source of Toxoplasma gondii, Cryptosporidium parvum.
- Cat feces (e.g. cat litter): source of Toxoplasma gondii, Bartonella spp.
- Soil/dust in areas where there is known histoplasmosis, coccidiomycosis.
- Reptiles, chicks, and ducklings that are a common source of Salmonella.
- Unprotected sexual intercourse with individuals with known sexually transmitted infections.
Prophylactic medications
Individuals at higher risk are often prescribed prophylactic medication to prevent an infection from occurring. A patient's risk level for developing an opportunistic infection is approximated using the patient's CD4 T-cell count and sometimes other markers of susceptibility. Common prophylaxis treatments include the following:[53]
Infection | When to Give Prophylaxis | Agent |
---|---|---|
Pneumocystis jirovecii | CD4 < 200 cells/mm3 or oropharyngeal candidasis (thrush) | TMP-SMX |
Toxoplasma gondii | CD4 < 100 cells/mm3 and positive Toxoplasma gondii IgG immunoassay | TMP-SMX |
Mycobacterium avium complex | CD4 < 50 | Azithromycin |
Treatment
Treatment depends on the type of opportunistic infection, but usually involves different antibiotics.[citation needed]
Other animals
Opportunistic infections caused by feline leukemia virus and feline immunodeficiency virus retroviral infections can be treated with lymphocyte T-cell immunomodulator.
References
- ↑ 1.0 1.1 Justiz Vaillant AA, Qurie A (2021). "Immunodeficiency". StatPearls. Treasure Island (FL): StatPearls Publishing. PMID 29763203. Archived from the original on 2021-09-25. Retrieved 2021-03-09.
- ↑ 2.0 2.1 Schroeder MR, Stephens DS (2016-09-21). "Macrolide Resistance in Streptococcus pneumoniae". Frontiers in Cellular and Infection Microbiology. 6: 98. doi:10.3389/fcimb.2016.00098. PMC 5030221. PMID 27709102.
- ↑ Achermann Y, Goldstein EJ, Coenye T, Shirtliff ME (July 2014). "Propionibacterium acnes: from commensal to opportunistic biofilm-associated implant pathogen". Clinical Microbiology Reviews. 27 (3): 419–40. doi:10.1128/CMR.00092-13. PMC 4135900. PMID 24982315.
- ↑ Caballero MT, Polack FP (May 2018). "Respiratory syncytial virus is an "opportunistic" killer". Pediatric Pulmonology. 53 (5): 664–667. doi:10.1002/ppul.23963. PMC 5947624. PMID 29461021.
- ↑ Czepiel J, Dróżdż M, Pituch H, Kuijper EJ, Perucki W, Mielimonka A, et al. (July 2019). "Clostridium difficile infection: review". European Journal of Clinical Microbiology & Infectious Diseases. 38 (7): 1211–1221. doi:10.1007/s10096-019-03539-6. PMC 6570665. PMID 30945014.
- ↑ Guh AY, Kutty PK (October 2018). "Clostridioides difficile Infection". Annals of Internal Medicine. 169 (7): ITC49–ITC64. doi:10.7326/AITC201810020. PMC 6524133. PMID 30285209.
- ↑ Chahin A, Opal SM (March 2017). "Severe Pneumonia Caused by Legionella pneumophila: Differential Diagnosis and Therapeutic Considerations". Infectious Disease Clinics of North America. 31 (1): 111–121. doi:10.1016/j.idc.2016.10.009. PMC 7135102. PMID 28159171.
- ↑ Berjeaud JM, Chevalier S, Schlusselhuber M, Portier E, Loiseau C, Aucher W, et al. (2016-04-08). "Legionella pneumophila: The Paradox of a Highly Sensitive Opportunistic Waterborne Pathogen Able to Persist in the Environment". Frontiers in Microbiology. 7: 486. doi:10.3389/fmicb.2016.00486. PMC 4824771. PMID 27092135.
- ↑ Falkinham JO (2018). "Mycobacterium avium complex: Adherence as a way of life". AIMS Microbiology. 4 (3): 428–438. doi:10.3934/microbiol.2018.3.428. PMC 6604937. PMID 31294225.
- ↑ Pan SW, Shu CC, Feng JY, Su WJ (June 2020). "Treatment for Mycobacterium avium complex lung disease". Journal of the Formosan Medical Association = Taiwan Yi Zhi. 119 Suppl 1: S67–S75. doi:10.1016/j.jfma.2020.05.006. PMID 32446754.
- ↑ Gordon SV, Parish T (April 2018). "Microbe Profile: Mycobacterium tuberculosis: Humanity's deadly microbial foe". Microbiology. 164 (4): 437–439. doi:10.1099/mic.0.000601. PMID 29465344.
- ↑ Pang Z, Raudonis R, Glick BR, Lin TJ, Cheng Z (January–February 2019). "Antibiotic resistance in Pseudomonas aeruginosa: mechanisms and alternative therapeutic strategies". Biotechnology Advances. 37 (1): 177–192. doi:10.1016/j.biotechadv.2018.11.013. PMID 30500353.
- ↑ Lamas A, Miranda JM, Regal P, Vázquez B, Franco CM, Cepeda A (January 2018). "A comprehensive review of non-enterica subspecies of Salmonella enterica". Microbiological Research. 206: 60–73. doi:10.1016/j.micres.2017.09.010. PMID 29146261.
- ↑ Jenul C, Horswill AR (April 2019). "Regulation of Staphylococcus aureus Virulence". Microbiology Spectrum. 7 (2). doi:10.1128/microbiolspec.GPP3-0031-2018. PMC 6452892. PMID 30953424.
- ↑ Kong C, Neoh HM, Nathan S (March 2016). "Targeting Staphylococcus aureus Toxins: A Potential form of Anti-Virulence Therapy". Toxins. 8 (3): 72. doi:10.3390/toxins8030072. PMC 4810217. PMID 26999200.
- ↑ Jespersen MG, Lacey JA, Tong SY, Davies MR (December 2020). "Global genomic epidemiology of Streptococcus pyogenes". Infection, Genetics and Evolution. 86: 104609. doi:10.1016/j.meegid.2020.104609. PMID 33147506.
- ↑ Brouwer S, Barnett TC, Rivera-Hernandez T, Rohde M, Walker MJ (November 2016). "Streptococcus pyogenes adhesion and colonization". FEBS Letters. 590 (21): 3739–3757. doi:10.1002/1873-3468.12254. hdl:10033/619157. PMID 27312939. S2CID 205213711.
- ↑ Latgé JP, Chamilos G (December 2019). "Aspergillus fumigatus and Aspergillosis in 2019". Clinical Microbiology Reviews. 33 (1): e00140–18, /cmr/33/1/CMR.00140–18.atom. doi:10.1128/CMR.00140-18. PMC 6860006. PMID 31722890.
- ↑ 19.0 19.1 José RJ, Periselneris JN, Brown JS (June 2020). "Opportunistic bacterial, viral and fungal infections of the lung". Medicine. 48 (6): 366–372. doi:10.1016/j.mpmed.2020.03.006. PMC 7206443. PMID 32390758.
- ↑ Akpan A, Morgan R (August 2002). "Oral candidiasis". Postgraduate Medical Journal. 78 (922): 455–9. doi:10.1136/pmj.78.922.455. PMC 1742467. PMID 12185216.
- ↑ Erdogan A, Rao SS (April 2015). "Small intestinal fungal overgrowth". Current Gastroenterology Reports. 17 (4): 16. doi:10.1007/s11894-015-0436-2. PMID 25786900. S2CID 3098136.
- ↑ Mu A, Shein TT, Jayachandran P, Paul S (2017-09-14). "Immune Reconstitution Inflammatory Syndrome in Patients with AIDS and Disseminated Coccidioidomycosis: A Case Series and Review of the Literature". Journal of the International Association of Providers of AIDS Care. 16 (6): 540–545. doi:10.1177/2325957417729751. PMID 28911256.
- ↑ Kwon-Chung KJ, Fraser JA, Doering TL, Wang Z, Janbon G, Idnurm A, Bahn YS (July 2014). "Cryptococcus neoformans and Cryptococcus gattii, the etiologic agents of cryptococcosis". Cold Spring Harbor Perspectives in Medicine. 4 (7): a019760. doi:10.1101/cshperspect.a019760. PMC 4066639. PMID 24985132.
- ↑ Maziarz EK, Perfect JR (March 2016). "Cryptococcosis". Infectious Disease Clinics of North America. 30 (1): 179–206. doi:10.1016/j.idc.2015.10.006. PMC 5808417. PMID 26897067.
- ↑ Horwath MC, Fecher RA, Deepe GS (2015-06-10). "Histoplasma capsulatum, lung infection and immunity". Future Microbiology. 10 (6): 967–75. doi:10.2217/fmb.15.25. PMC 4478585. PMID 26059620.
- ↑ Mittal J, Ponce MG, Gendlina I, Nosanchuk JD (2018). Rodrigues ML (ed.). "Histoplasma Capsulatum: Mechanisms for Pathogenesis". Current Topics in Microbiology and Immunology. Cham: Springer International Publishing. 422: 157–191. doi:10.1007/82_2018_114. ISBN 978-3-030-30236-8. PMC 7212190. PMID 30043340.
- ↑ Seyedmousavi S, Bosco SM, de Hoog S, Ebel F, Elad D, Gomes RR, et al. (April 2018). "Fungal infections in animals: a patchwork of different situations". Medical Mycology. 56 (suppl_1): 165–187. doi:10.1093/mmy/myx104. PMC 6251577. PMID 29538732.
- ↑ Stentiford GD, Becnel JJ, Weiss LM, Keeling PJ, Didier ES, Bjornson S, et al. (April 2016). "Microsporidia - Emergent Pathogens in the Global Food Chain". Trends in Parasitology. 32 (4): 336–348. doi:10.1016/j.pt.2015.12.004. PMC 4818719. PMID 26796229.
- ↑ Sokulska M, Kicia M, Wesołowska M, Hendrich AB (October 2015). "Pneumocystis jirovecii--from a commensal to pathogen: clinical and diagnostic review". Parasitology Research. 114 (10): 3577–85. doi:10.1007/s00436-015-4678-6. PMC 4562001. PMID 26281787.
- ↑ Gerace E, Lo Presti VD, Biondo C (December 2019). "Cryptosporidium Infection: Epidemiology, Pathogenesis, and Differential Diagnosis". European Journal of Microbiology & Immunology. 9 (4): 119–123. doi:10.1556/1886.2019.00019. PMC 6945992. PMID 31934363.
- ↑ Mendez OA, Koshy AA (July 2017). Gubbels MJ (ed.). "Toxoplasma gondii: Entry, association, and physiological influence on the central nervous system". PLOS Pathogens. 13 (7): e1006351. doi:10.1371/journal.ppat.1006351. PMC 5519211. PMID 28727854.
- ↑ Hunter CA, Sibley LD (November 2012). "Modulation of innate immunity by Toxoplasma gondii virulence effectors". Nature Reviews. Microbiology. 10 (11): 766–78. doi:10.1038/nrmicro2858. PMC 3689224. PMID 23070557.
- ↑ Fonseca Brito L, Brune W, Stahl FR (August 2019). "Cytomegalovirus (CMV) Pneumonitis: Cell Tropism, Inflammation, and Immunity". International Journal of Molecular Sciences. 20 (16): 3865. doi:10.3390/ijms20163865. PMC 6719013. PMID 31398860.
- ↑ Bohra C, Sokol L, Dalia S (2017-11-01). "Progressive Multifocal Leukoencephalopathy and Monoclonal Antibodies: A Review". Cancer Control. 24 (4): 1073274817729901. doi:10.1177/1073274817729901. PMC 5937251. PMID 28975841.
- ↑ Kartau M, Sipilä JO, Auvinen E, Palomäki M, Verkkoniemi-Ahola A (2019-12-02). "Progressive Multifocal Leukoencephalopathy: Current Insights". Degenerative Neurological and Neuromuscular Disease. 9: 109–121. doi:10.2147/DNND.S203405. PMC 6896915. PMID 31819703.
- ↑ Radu O, Pantanowitz L (February 2013). "Kaposi sarcoma". Archives of Pathology & Laboratory Medicine. 137 (2): 289–94. doi:10.5858/arpa.2012-0101-RS. PMID 23368874.
- ↑ Cesarman E, Damania B, Krown SE, Martin J, Bower M, Whitby D (January 2019). "Kaposi sarcoma". Nature Reviews. Disease Primers. 5 (1): 9. doi:10.1038/s41572-019-0060-9. PMC 6685213. PMID 30705286.
- ↑ Africa CW, Nel J, Stemmet M (July 2014). "Anaerobes and bacterial vaginosis in pregnancy: virulence factors contributing to vaginal colonisation". International Journal of Environmental Research and Public Health. 11 (7): 6979–7000. doi:10.3390/ijerph110706979. PMC 4113856. PMID 25014248.
- ↑ Mastromarino P, Vitali B, Mosca L (July 2013). "Bacterial vaginosis: a review on clinical trials with probiotics" (PDF). The New Microbiologica. 36 (3): 229–38. PMID 23912864. Archived (PDF) from the original on 2015-05-18. Retrieved 2022-10-04.
- ↑ Mastromarino P, Vitali B, Mosca L (July 2013). "Bacterial vaginosis: a review on clinical trials with probiotics" (PDF). The New Microbiologica. 36 (3): 229–38. PMID 23912864. Archived (PDF) from the original on 2015-05-18. Retrieved 2022-10-04.
- ↑ Knoester M, Lashley LE, Wessels E, Oepkes D, Kuijper EJ (April 2011). "First report of Atopobium vaginae bacteremia with fetal loss after chorionic villus sampling". Journal of Clinical Microbiology. 49 (4): 1684–6. doi:10.1128/JCM.01655-10. PMC 3122803. PMID 21289141.
- ↑ Doitsh G, Greene WC (March 2016). "Dissecting How CD4 T Cells Are Lost During HIV Infection". Cell Host & Microbe. 19 (3): 280–91. doi:10.1016/j.chom.2016.02.012. PMC 4835240. PMID 26962940.
- ↑ Fenwick C, Joo V, Jacquier P, Noto A, Banga R, Perreau M, Pantaleo G (November 2019). "T-cell exhaustion in HIV infection". Immunological Reviews. 292 (1): 149–163. doi:10.1111/imr.12823. PMC 7003858. PMID 31883174.
- ↑ Bruchfeld J, Correia-Neves M, Källenius G (February 2015). "Tuberculosis and HIV Coinfection". Cold Spring Harbor Perspectives in Medicine. 5 (7): a017871. doi:10.1101/cshperspect.a017871. PMC 4484961. PMID 25722472.
- ↑ Tenforde MW, Shapiro AE, Rouse B, Jarvis JN, Li T, Eshun-Wilson I, Ford N, et al. (Cochrane Infectious Diseases Group) (July 2018). "Treatment for HIV-associated cryptococcal meningitis". The Cochrane Database of Systematic Reviews. 2018 (7): CD005647. doi:10.1002/14651858.CD005647.pub3. PMC 6513250. PMID 30045416.
- ↑ Rees CA, Keating EM, Lukolyo H, Danysh HE, Scheurer ME, Mehta PS, et al. (August 2016). "Mapping the Epidemiology of Kaposi Sarcoma and Non-Hodgkin Lymphoma Among Children in Sub-Saharan Africa: A Review". Pediatric Blood & Cancer. 63 (8): 1325–31. doi:10.1002/pbc.26021. PMC 7340190. PMID 27082516.
- ↑ Sadiq U, Shrestha U, Guzman M (2021). "Prevention Of Opportunistic Infections In HIV". StatPearls. Treasure Island (FL): StatPearls Publishing. PMID 30020717. Archived from the original on 2022-06-17. Retrieved 2021-03-09.
- ↑ Schlossberg D (2015-04-23). Clinical Infectious Disease. Cambridge University Press. pp. 688–. ISBN 978-1-107-03891-2.
- ↑ Ledergerber B, Egger M, Erard V, Weber R, Hirschel B, Furrer H, et al. (December 1999). "AIDS-related opportunistic illnesses occurring after initiation of potent antiretroviral therapy: the Swiss HIV Cohort Study". JAMA. 282 (23): 2220–6. doi:10.1001/jama.282.23.2220. PMID 10605973.
- ↑ Brooks JT, Kaplan JE, Holmes KK, Benson C, Pau A, Masur H (March 2009). "HIV-associated opportunistic infections--going, going, but not gone: the continued need for prevention and treatment guidelines". Clinical Infectious Diseases. 48 (5): 609–11. doi:10.1086/596756. PMID 19191648.
- ↑ Freifeld AG, Bow EJ, Sepkowitz KA, Boeckh MJ, Ito JI, Mullen CA, et al. (February 2011). "Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 update by the infectious diseases society of america". Clinical Infectious Diseases. 52 (4): e56-93. doi:10.1093/cid/cir073. PMID 21258094.
- ↑ Smith TJ, Khatcheressian J, Lyman GH, Ozer H, Armitage JO, Balducci L, et al. (July 2006). "2006 update of recommendations for the use of white blood cell growth factors: an evidence-based clinical practice guideline". Journal of Clinical Oncology. 24 (19): 3187–205. doi:10.1200/JCO.2006.06.4451. PMID 16682719.
- ↑ 53.0 53.1 "Guidelines for the prevention and treatment of opportunistic infections in adults and adolescents with HIV: recommendations from the Centers for Disease Control and Prevention, the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America" (PDF). 26 May 2020. Archived (PDF) from the original on 28 November 2020. Retrieved 28 November 2020.
External links
Classification |
---|