Infectious Disease Research

Chronic Infectious Diseases

Prof. Garth L. Nicolson

Respiratory Diseases

Chronic respiratory diseases, such as chronic asthma, airway inflammation, chronic pneumonia and other respiratory diseases, are known to be associated with chronic infections. For example, mycoplasmal infections are a common cause of upper respiratory infections, and severe asthma is commonly associated with mycoplasmal infections. These are complex diseases of largely unknown etiology, but in many cases chronic infections are to blame. Some infections, such as those caused by certain Mycoplasma and Chlaymdia species that are invasive and are found in respiratory epithelial cells are able to suppress immune responses by suppressing the ability of pulmonary macrophages to ingest and kill these infectious agents. Although we do not know exactly what causes respiratory diseases, there is increasing evidence that in many patients chronic infections, particularly by certain bacteria and viruses, play an important role in these diseases along with genetic predisposition and immune dysfunction.

Although mycoplasmal infections are often associated with Chronic Asthma, the exact role of mycoplasmas in the pathogenesis of Asthma remains unclear. Certain Mycoplasma species are involved in respiratory tract infections associated with airway inflammations, induction of bronchial hyperresponsiveness (BHR) and asthmatic attacks. At a minimum, M. pneumoniae infections can cause worsening of conditions in asthmatic patients, whose attacks are associated with significant and specific immune responses. Mycoplasmas are only one of many agents that can trigger BHR, and other infectious or chemical agents may contribute to the complex disease process. Such infectious agents could be involved in helping to cause the illness, or they can affect patients by serving as cofactors for the illness (not causing illness on their own but serving as important factors in the disease process) or even as opportunistic infections that increase patient morbidity (sickness) and complications associated with the disease (see Nicolson et al., Antimicrobics and Infectious Diseases Newsletter, 1999 ; 17(11):81-88).

Urogenital Diseases

We and others have found that Mycoplasma species are commonly present in urogenital infections. For example, mycoplasmal infections were detected in more than 12% of females who presented at gynecological services, and they are associated with acute and nonspecific non-gonococcal urethritis in males but not in asymptomatic controls. This type of microorganism is also a common cause of genital infections in women, and it was detectable in 7% of women with sexually transmitted diseases. Mycoplasmal and other chronic bacteria have been implicated in a wide variety of urogenital diseases, such as pelvic inflammatory disease, infertility, non-gonococcal urethritis (NGU) and other genital infections, pyelonephritis, Reiter's syndrome, and peritonitis. The appearance of various bacterial species in bacterial vaginosis may be a result of pathophysiological alterations of the vaginal ecosystem, and mycoplasmas appear to play an important role in this process. Mycoplasmas are also known to interfere in pregnancy and are thought to be involved in at least 11% of patients with fertility problems.

Immunosuppressive Diseases

Some Mycoplasma species, M. fermentans, M. penetrans, and M. pirum, have been implicated as infectious cofactors in HIV-AIDS. Using relatively insensitive techniques all three mycoplasmas have been detected in up to 20% of patients with HIV infections, and serological studies have suggested that the presence of M. penetrans is also associated with HIV infection. Moreover, the incidence of systemic mycoplasmal infections in HIV-AIDS patients is probably much, much higher than previously thought and may approach 80% or more. Most of the older analyses were performed using relatively insensitive techniques, such as serological analysis. Pathogenic Mycoplasma species may influence HIV pathogenesis by specific and direct activation or suppression of the immune system, the production of superantigens with subsequent alterations in immune responses, or by their contribution to the oxidative stress observed in HIV-positive patients. Also, the development of AIDS may increase the susceptibility of HIV-infected patients for coinfection with various Mycoplasma species, such as M. fermentans. This species is able to bind HIV capsid protein gp120 permitting adhesion of HIV virions to the mycoplasma surface. Subsequently the HIV viruses could be transported directly to cells expressing specific receptors. After binding to target cells, mycoplasmas can stimulate host cell activation by releasing certain cytokine mediators, which are known effectors for virus reproduction.

Antigen similarities between the surface components of mycoplasmas and HIV-1 have led to speculation that they use similar mechanisms for cell entry. For example, the HIV-1 gp120 envelope glycoprotein and M. genitalium adhesion proteins share protein sequence homology and also have significant similarity with the binding site proteins. The interactions of microorganisms with certain antigens on host cells could contribute to a number of possible outcomes, including immune cell dysfunction, depletion, cell shift (to other subsets of immune cells), antibody-producing immune cell proliferation, hyperglobulinemia (a state where certain immunoglobulin proteins of the same class are overproduced) and antigen-presenting cell dysfunction (antigen presentation to the immune system is a very important step in immunity). Interestingly, all of these have been observed during the development of HIV-AIDS, and this makes certain microorganisms like mycoplasmas so important to understand this disease process.

Cardiac Diseases

Mycoplasmal and chlamydial infections of the heart have been reported in patients with different types of carditis or heart infections. The most common association was with M. pneumoniae or C. pneumoniae infection. Endocarditis and myocarditis associated with mycoplasmal and chlamydial infections appear to be an important cause of death. Direct bacterial invasion of M. pneumoniae into pericardial tissue appears to be more likely to cause pericarditis than autoimmune phenomena. Viral and bacterial (Mycoplasma, Chlamydia and Mycobacterium tuberculosis) infections appear to be common causes of myocarditis and/or pericarditis (infections of the muscle and cell lining of the heart), and this is just beginning to be appreciated by infectious disease specialists.



  • Pathogenic Mycoplasma Infections in Chronic Illnesses: General
    Considerations in Selecting Conventional and Integrative Treatments,
    Prof. Garth L. Nicolson, International Journal of Clinical Medicine, 2019;
    10: 477-522.

  • Role of Chronic Bacterial and Viral Infections in Neurodegenerative, Neurobehavioral, Psychiatric, Autoimmune and Fatiguing Illnesses: Part 1, by Prof. Garth L. Nicolson and Jörg Haier, British Journal of Medical Practitioners 2009; 2(4): 20-28. pdf doc

  • Role of Chronic Bacterial and Viral Infections in Neurodegenerative, Neurobehavioral, Psychiatric, Autoimmune and Fatiguing Illnesses: Part 2, by Prof. Garth L. Nicolson and Jörg Haier, British Journal of Medical Practitioners 2010; 3(1): 301-311. pdf doc

  • Mycoplasma and other intracellular bacterial infections in rheumatic diseases: comorbid condition or cause? by Prof. Garth L. Nicolson, Open Journal of Tropical Medicine 2017; 1: 016-017. pdf_doc

  • Lipid Replacement Therapy with a glycophospholipid formulation with NADH and CoQ10 significantly reduces fatigue in intractable chronic fatiguing illnesses and chronic Lyme disease, by G.L. Nicolson, R. Settineri and R.R. Ellithorpe, International Journal of Clinical Medicine 2013; 3(3): 163-170. pdf_doc

  • Chronic Fatigue Syndrome Patients Subsequently Diagnosed with Lyme Disease Borrelia burgdorferi: Evidence for Mycoplasma species Co-Infections - by Garth L. Nicolson,  Nancy L. Nicolson, and Joerg Haier, Journal of Chronic Fatigue Syndrome 2008; 14(4): 5-17. - pdf doc

  • Chronic Bacterial and Viral Infections in Neurodegenerative and Neurobehavioral Diseases, by Prof. Garth Nicolson, Laboratory Medicine, 2008; 39(5):291-299. pdf doc

  • Multiple Co-Infections (Mycoplasma, Chlamydia, Human Herpes Virus-6) in Blood of Chronic Fatigue Syndrome Patients. by G.L. Nicolson et al., Journal of Chronic Fatigue Syndrome 2003; 11(2):7-19 pdf doc

  • High prevalence of mycoplasmal infections among European Chronic Fatigue Syndrome patients. Examination of four Mycoplasma species in Chronic Fatigue Syndrome patients., by J. Nigs et al., FEMS Immunol. Med. Microbiol. 2002; 34: 209-214. pdf doc

  • Bacterial and Viral Co-Infections in Chronic Fatigue Syndrome (CFS/ME) Patients, by Nicolson et al., Proc. Clinical & Scientific Conference on Myalgic Encephalopathy/Chronic Fatigue Syndrome, the Practitioners Challenge, Alison Hunter Foundation, Sydney, Australia 2002 pdf doc

  • Diagnosis and integrative treatment of intracellular bacterial infections in Chronic Fatigue and Fibromyalgia Syndromes, Gulf War Illness, Rheumatoid Arthritis and other chronic illnesses., by G.L. Nicolson et al., Clin. Pract. Alt. Medicine 2000;1(2): 92-102. pdf doc

  • Examination of mycoplasmas in blood of 565 Chronic Illness patients by polymerase chain reaction., by M. Naralla et al., Intern. J. Med. Biol. Environ. 2000; 28(1): 15-23. pdf doc

  • Infectious Causes of Chronic Inflammatory Diseases and Cancer, by Gail H.
    Cassell, Emerging Infectious Disease 1998; 4(3): 475-487 
    pdf doc

  • Role of Mycoplasmal Infections in Fatigue Illnesses: Chronic Fatigue and Fibromyalgia Syndromes, Gulf War Illness and Rheumatoid Arthritis, by G.L. Nicolson et al.,  J. Chronic Fatigue Syndr. 2000; 6(3/4):23-39 pdf doc

  • Identification And Treatment Of Chronic Infections In CFIDS, Fibromyalgia Syndrome And Rheumatoid Arthritis, by G.L. Nicolson et al., CFIDS Chronicle 1999; 12(3): 19-21 pdf doc

  • Mycoplasmal Infections in Chronic Illnesses: Fibromyalgia and Chronic Fatigue Syndromes, Gulf War Illness, HIV-AIDS and Rheumatoid Arthritis, by G.L. Nicolson et al., Medical Sentinel 1999; 4:172-176 pdf doc

  • Role of Mycoplasmal Infections in Fatigue Illnesses: Chronic Fatigue and Fibromyalgia Syndromes, Gulf War Illness and Rheumatoid Arthritis, by G.L. Nicolson et al., The Clinical and Scientific Basis of CFS, Sydney, 1999 pdf doc

  • The Pathogenesis And Treatment Of Mycoplasmal Infections, by G.L. Nicolson et al., Antimicrob. Infect. Dis. Newsl. 1999; 17(11) : 81-88 pdf doc

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  • Mycoplasma – Often overlooked in chronic Lyme Disease - by Scott Forsgren, Public Health Alert 2009; 7(4):1-10. pdf doc

  • Diagnosis and therapy of chronic systemic co-infections in Lyme Disease and other tick-borne infectious diseases, by Prof. Garth Nicolson, Townsend Lett. Doctors  2007; 285: 93-98  pdf doc

  • Systemic intracellular bacterial infections (Mycoplasma, Chlamydia, Borrelia species) in neurodegenerative (MS, ALS) and behavioral disorders (ASD), by Prof. Garth Nicolson, Infectious Disease Newsletter, 2007   (high res.) - pdf doc

  • Diagnosis and Therapy of Chronic Systemic Co-infections In Lyme Disease and Other Tick-Borne Infectious Diseases, by Prof. G.L. Nicolson, American Academy for Advancement in Medicine, 2006 rtf doc

  • Chronic Co-Infections in Chronic Fatigue Syndrome, Fibromyalgia Syndrome and Other Chronic Illnesses, by Garth Nicolson and Paul Berns, CFS Newsletter, 2002. rtf doc

  • Mycology News for Health Practitioners, Vol. 1, No. 6, Feb. 2002 rtf doc

  • Mycoplasmas: the Missing Link in Fatiguing Illnesses, by Michael Guthrie, Alternative Medicine; 2001; Sept: 60-70. rtf doc

  • Autoimmune Neurological and Rheumatic Diseases: Role of Chronic Infections in Morbitity and Progression, by Garth Nicolson and Nancy Nicolson, Proc. 13th Intern. Symp. Integrative Medicine 2001; 13: 104-112. rtf doc

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