Antibodies to mycoplasma fermentans in HIV-positive heterosexual patients: seroprevalence and association with AIDS

Association of Mycoplasma fermentans and the risk of HIV-1 infection: A meta-analysis

BACKGROUND

Previous studies have reported the association between Mycoplasma fermentans (M. fermentans) and the risk of human immunodeficiency virus 1 (HIV-1) infection, but the results were inconsistent. The present study aims to systematically review reported studies on M. fermentans and its association with HIV-1 infection, as well as to summarize the findings using a meta-analysis.

METHODS

Studies meeting the inclusion criteria in the PubMed, Embase, China National Knowledge Infrastructure, WanFang Data, and Chongqing VIP databases up to March 2019 were identified. Cochran Q and I statistics were used to assess heterogeneity. Additionally, pooled odds ratio (OR) with 95% confidence intervals (CI) were calculated and displayed by Forest plots. Also, the funnel plot, Begg test, and Egger test were used to evaluate potential publication bias. In addition, the source of heterogeneity was investigated by subgroup and sensitivity analyses.

RESULTS

A total of 11 studies comprising 1028 HIV-1-positive patients and 1298 controls were ultimately included in this meta-analysis. Our results indicated that M. fermentans could increase the risk of HIV-1 infection among humans (OR = 3.66, 95%CI 1.26-10.64). Subgroup analysis showed that the risk of HIV-1 infection associated with M. fermentans was, based on the geographical distribution, 1.19 (95%CI 0.33-4.33) in Europe, 2.83 (95%CI 0.94-8.52) in United States, 11.92 (95%CI 3.93-36.15) in Asia; based on the source of the sample, 2.97 (95%CI 0.89-9.95) in blood samples, 4.36 (95%CI 1.63-11.68) in urine samples; based on the detection method, 2.80 (95%CI 0.72-10.96) with the polymerase chain reaction method, 5.54 (95%CI 1.21-25.28) with other detection methods; based on the source of controls, 1.91 (95%CI 0.53-6.89) in sexually transmitted diseases individuals, and 8.25 (95%CI 2.16-31.60) in health individuals.

CONCLUSION

Our study revealed evidence of the association between M. fermentans and HIV-1 infection. Considering the heterogeneity, further studies are warranted to understand the relationship between M. fermentans and HIV-1 infection.

Presence of Mycoplasma fermentans in the bloodstream of Mexican patients with rheumatoid arthritis and IgM and IgG antibodies against whole microorganism

Background

Increasing evidence incriminates bacteria, especially Mycoplasma fermentans, as possible arthritogenic agents in humans. The purpose of this study was to investigate M. fermentans in the bloodstream of patients with rheumatoid arthritis.

Methods

Two hundred and nineteen blood samples from patients with rheumatoid arthritis, systemic lupus erythematosus, antiphospholipid syndrome, and healthy individuals were screened by bacterial culture and direct PCR in order to detect mycoplasmas; IgM and IgG against M. fermentans PG18 were also detected by ELISA and Immunoblotting assays in patients with rheumatoid arthritis and healthy individuals.

Results

Blood samples from patients with antiphospholipid syndrome and healthy individuals were negative for mycoplasma by culture or direct PCR. In blood samples from patients with systemic lupus erythematosus were detected by direct PCR M. fermentans in 2/50 (2%), M. hominis in 2/50 (2%) and U. urealyticum in 1/50 (0.5%). In patients with RA M. fermentans was detected by culture in 13/87 blood samples and in 13/87 by direct PCR, however, there was only concordance between culture and direct PCR in six samples, so M. fermentans was detected in 20/87(23%) of the blood samples from patients with RA by either culture or PCR. Antibody-specific ELISA assay to M. fermentans PG18 was done, IgM was detected in sera from 40/87 patients with RA and in sera of 7/67 control individuals, IgG was detected in sera from 48/87 RA patients and in sera from 7/67 healthy individuals. Antibody-specific immunoblotting to M. fermentans PG18 showed IgM in sera from 35/87 patients with RA and in sera from 4/67 healthy individuals, IgG was detected in sera from 34/87 patients and in sera from 5/67 healthy individuals.

Conclusion

Our findings show that only M. fermentans produce bacteremia in a high percentage of patients with RA. This finding is similar to those reported in the literature. IgM and IgG against M. fermentans PG18 were more frequent in patients with RA than healthy individuals.

Submasseteric abscess caused by Mycoplasma salivarium infection

Mycoplasma salivarium preferentially resides in the human oral cavity. Unlike other Mycoplasma species, M. salivarium has not been regarded as a pathogen, although one case of M. salivarium-caused arthritis in a patient with hypogammaglobulinemia has been reported. We describe the first case of submasseteric abscess caused by M. salivarium.

The inhibitory effect of Mycoplasma fermentans on tumour necrosis factor (TNF)-alpha-induced apoptosis resides in the membrane lipoproteins

Mycoplasma have been shown to be involved in the alteration of several eukaryotic cell functions, such as cytokine production, gene expression and more. We have previously reported that infection of human myelomonocytic U937 cell line with live Mycoplasma fermentans (M. fermentans) inhibited tumour necrosis factor (TNF-alpha)-induced apoptosis. Mycoplasmal membrane lipoproteins are considered to be the most potent initiators of inflammatory reactions in mycoplasmal infections. The aim of this study was to clarify whether the inhibitory effect on TNFalpha-induced apoptosis is exerted by M. fermentans lipoproteins (LPMf). A significant reduction in TNFalpha-induced apoptosis was demonstrated by stimulation of U937 cells with M. fermentans total proteins, LPMf or MALP-2 (M. fermentans synthetic lipopeptide), but not with M. fermentans hydrophilic protein preparation (AqMf). To investigate the mechanism of M. fermentans antiapoptotic effect, the reduction of mitochondrial transmembrane potential (delta psi m) was measured. M. fermentans total proteins LPMf and MALP-2, but not AqMf, inhibited the reduction of delta psi m. In addition, M. fermentans total proteins LPMf and MALP-2, but not AqMf, downregulated the formation of active caspase-8. NF-kappaB was transactivated in cells treated with M. fermentans lipoproteins, and was essential for host cell survival, but not for the inhibition of TNFalpha-induced apoptosis by LPMf. Our results suggest that the inhibitory effect exerted by M. fermentans on TNFalpha-induced apoptosis in U937 cells is due to the membrane lipoproteins of these bacteria.

Mycoplasma fermentans inhibits tumor necrosis factor alpha-induced apoptosis in the human myelomonocytic U937 cell line

Mycoplasma fermentans (M. fermentans) was shown to be involved in the alteration of several eukaryotic cell functions (i.e. cytokine production, gene expression), and was suggested as a causative agent in arthritic diseases involving impaired apoptosis. We investigated whether M. fermentans has a pathogenic potential by affecting tumor necrosis factor (TNF)alpha-induced apoptosis in the human myelomonocytic U937 cell line. A significant reduction in the TNFalpha-induced apoptosis (approximately 60%) was demonstrated upon either infection with live M. fermentans or by stimulation with non-live M. fermentans. To investigate the mechanism of M. fermentans antiapoptotic effect, the reduction of mitochondrial transmembrane potential (DeltaPsim) and the protease activity of caspase-8 were measured. In the infected cells, the reduction of DeltaPsim was inhibited (approximately 75%), and an approximately 60% reduction of caspase-8 activity was measured. In conclusion, M. fermentans significantly inhibits TNFalpha-induced apoptosis in U937 cells, and its effect is upstream of the mitochondria and upstream of caspase-8.

HIV, 'an evolving species'. Roles of cellular activation and co-infections

Each small variation of the genome of a species can be preserved if it is useful for the survival of the species in a given environment. Within this framework, the finality of the biological cycle of HIV consists in a search for harmony (biological coherence) with man, which is to say a stable condition. Cellular activation appears to be the strategy developed by HIV in order to achieve this coherence. The price of this strategy is the AIDS. The first contact between HIV and immune system appears to determine the subsequent clinical outcome and the future of HIV. Lymphocytic activation varies during the course of the vital cycle of HIV. For each individual, this lymphocytic activation depends on both the HLA repertoire acquired during thymic ontogenesis and the antigenic experience before and after HIV infection. Thus intercurrent infections alter the immune condition of the organism and influence the outcome of HIV. We described a synthetic analysis of the effects of HIV on the surface protein expression and the cellular activation pathways which should provide insights in the evolutionary relationship between HIV and man and should permit to do a more physiological therapeutic approach.