Mycoplasma penetrans and other mycoplasmas in urine of human immunodeficiency virus-positive children

[Clinical implications of the genus Mycoplasma]

Dentro del género Mycoplasma, las especies que tradicionalmente se han relacionado con cuadros infecciosos han sido principalmente M. pneumoniae, M. genitalium, M. hominis o U. urealyticum. Sin embargo, existen otras muchas que están implicadas y, que muchas veces, son desconocidas para los profesionales sanitarios. El objetivo de esta revisión es identificar todas las especies del género Mycoplasma que se han aislado en el hombre y determinar su participación en la patología infecciosa humana.

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.

Mycoplasma genitalium: an emerging sexually transmitted pathogen

Mycoplasma genitalium is a member of genital mycoplasmas, which is emerging as an important causative agent of sexually transmitted infections both in males and females. The advent of polymerase chain reaction and other molecular methods have made studies on M. genitalium more feasible, which is otherwise a difficult organism to isolate. Besides Chlamydia trachomatis, M. genitalium is now an important and established cause of non gonococcal urethritis (NGU) in men, more so in persistent and recurrent NGU. Multiple studies have also shown a positive association of M. genitalium with mucopurulent cervicitis and vaginal discharge in females as well. The evidences for M. genitalium pelvic inflammatory diseases and infertility are quite convincing and indicate that this organism has potential to cause ascending infection. Lack of clear association with M. genitalium has been reported for bacterial vaginosis and adverse pregnancy outcomes. Diagnosis of M. genitalium infections is performed exclusively using nucleic acid amplification tests (NAATs), owing to poor or slow growth of bacterium in culture. Although there are no guidelines available regarding treatment, macrolide group of antimicrobials appear to be more effective than tetracyclines. The present review provides an overview of the epidemiology, pathogenesis, clinical presentation and management of sexually transmitted infections due to M. genitalium.

Cold agglutinins in HIV-seropositive participants and diagnosis of respiratory disease due to Mycoplasma pneumoniae

OBJECTIVES

Cold agglutinin (CA) titers are one among the first pathological indicators for diagnosing Mycoplasma pneumoniae disease. We prospectively studied the prevalence of CAs in 300 HIV-positive and 75 HIV-negative individuals with respiratory disease in Chennai, India.

METHODS

The cold agglutination test was used and retrospectively compared with the results of a particle agglutination test.

RESULTS

While CAs were positive in 51 HIV cases, particle agglutination test detected anti-M pneumoniae antibodies from 43 cases with HIV disease (P = .001). The seroprevalence of CAs was 2.6% (n = 2) among HIV-negative participants. The mean CD4 count in CApositive and -negative HIV cases was 107.4 + 121.2 and 259.2 + 247.2 cells/microL (P = .001), respectively.

CONCLUSION

Our report suggests a basis for the existence of CAs in HIV-positive cases. Definitive diagnosis may be done only when CA detection is used in conjunction with a specific test.

Detection of pulmonary Mycoplasma pneumoniae infections in HIV-infected subjects using culture and serology

OBJECTIVE

The true prevalence of Mycoplasma pneumoniae infections involving the respiratory tracts of HIV-infected individuals is still unclear. This study examined the prevalence of M. pneumoniae in 100 HIV-infected individuals at an AIDS care center in Chennai, India, using conventional laboratory techniques and interpretation criteria.

METHODS

Diagnosis was based on culture, cold agglutination test, and commercial enzyme-linked immunosorbent assay (ELISA) for the qualitative determination of IgM antibodies against M. pneumoniae. The efficacies of the different diagnostic procedures used in the study were analyzed.

RESULTS

The prevalence of M. pneumoniae was 31% by culture and 21% by IgM ELISA. Cough (p=0.03, OR 3.8, 95% CI 1-17.8), myalgia (p=0.04, OR 2.5, 95% CI 1-6.6), rales (p=0.04, OR 2.4, 95% CI 1-6.6), and cervical adenopathy (p=0.03, OR 2.7, 95% CI 1-7.1) were the symptoms that significantly corroborated culture positivity. Patients positive for M. pneumoniae by culture or IgM antibody had significantly greater CD4+ T-cell depletion and anemia than those without any evidence of infection.

CONCLUSIONS

This study provides the means to diagnose M. pneumoniae infection and information on the prevalence of the pathogen in HIV-infected individuals in resource constrained settings. Although modern molecular techniques may provide more insight into the prevalence of M. pneumoniae in HIV-infected individuals, conventional methods can still be used in diagnosis.

The significance of Ureaplasma urealyticum as a pathogenic agent in the paediatric population

PURPOSE OF REVIEW

Ureaplasma urealyticum is a frequent commensal in the lower genital tract of sexually active women. It may be transmitted perinatally from the colonized mother to her offspring, often resulting in prematurity and neonatal disease. The microorganism also sustains a causative role for infectious diseases in older children.

RECENT FINDINGS

U. urealyticum infection can be diagnosed by culture, polymerase chain reaction, and the detection of specific antibodies. Neonatal infection has been implicated in various pathological conditions including pneumonia, chronic lung disease, central nervous system disorders, sepsis, osteomyelitis and even death. Older children may present with wheezing, pneumonitis, pertussis-like syndrome and different forms of arthritis. Large well-designed trials have demonstrated that the regular administration of antibiotics to vaginally colonized women are not beneficial in terms of preventing preterm labour. Macrolide-containing antibiotic regimens are, however, recommended for preterm premature rupture of the membranes. Erythromycin treatment of ureaplasma respiratory colonized premature infants shows no reduction in the incidence of chronic lung disease. Treatment of central nervous system infections, sepsis and arthritides includes tetracyclines, fluoroquinolones and anti-inflammatory agents, respectively.

SUMMARY

This review covers recent evidence concerning the role of U. urealyticum as a pathogen during childhood. It also includes an evaluation of contemporary diagnostic techniques and optimal therapeutic approaches.

Quantitative detection and phylogeny-based identification of mycoplasmas and ureaplasmas from human immunodeficiency virus type 1-positive patients

More than 20 years ago, Mycoplasma genitalium was first isolated from men with nongonococcal urethritis (NGU). Some strains of Mycoplasma and Ureaplasma are associated with NGU or other genitourinary infections. It is reasonable to suggest that mycoplasmas and ureaplasmas may increase the development of acquired immunodeficiency syndrome in human immunodeficiency virus type 1 (HIV-1)-infected patients. This study investigated a rapid and reliable diagnostic method, based on a LightCycler SYBER green I real-time PCR assay and phylogenetic analysis, for detecting mycoplasmas and ureaplasmas in urine from HIV-1-infected patients. Primers were designed to amplify a 711-bp fragment of the 16S rRNA gene. Positive PCR-amplified products were further sequenced, and a phylogenetic tree was constructed by neighbor joining of the V4 and V5 sequences from 15 prototypes strains. PCR-positive samples were detected in 17 (9.1%) urine samples, their prototypes being as follows: 2/17 (11.2%) M. genitalium, 1/17 (5.9%) M. hominis, 12/17 (70.6%) Ureaplasma urealyticum, 1/17 (5.9%) mixed M. genitalium and M. hominis, and 1/17 (5.9%) M. hominis and U. urealyticum, respectively. Mycoplasma and Ureaplasma load for each specimen was 3.8 x 10 copies/ml to 7.2 x 10(3) copies/ml. Overall, this study demonstrates that real-time PCR and phylogenetic analysis are the fastest available methods for the detection of mycoplasmas in the urogenital tract.

Mycoplasmas and ureaplasmas as neonatal pathogens

The genital mycoplasmas represent a complex and unique group of microorganisms that have been associated with a wide array of infectious diseases in adults and infants. The lack of conclusive knowledge regarding the pathogenic potential of Mycoplasma and Ureaplasma spp. in many conditions is due to a general unfamiliarity of physicians and microbiology laboratories with their fastidious growth requirements, leading to difficulty in their detection; their high prevalence in healthy persons; the poor design of research studies attempting to base association with disease on the mere presence of the organisms in the lower urogenital tract; the failure to consider multifactorial aspects of diseases; and considering these genital mycoplasmas only as a last resort. The situation is now changing because of a greater appreciation of the genital mycoplasmas as perinatal pathogens and improvements in laboratory detection, particularly with regard to the development of powerful molecular nucleic acid amplification tests. This review summarizes the epidemiology of genital mycoplasmas as causes of neonatal infections and premature birth; evidence linking ureaplasmas with bronchopulmonary dysplasia; recent changes in the taxonomy of the genus Ureaplasma; the neonatal host response to mycoplasma and ureaplasma infections; advances in laboratory detection, including molecular methods; and therapeutic considerations for treatment of systemic diseases.

The complete genomic sequence of Mycoplasma penetrans, an intracellular bacterial pathogen in humans

The complete genomic sequence of an intracellular bacterial pathogen, Mycoplasma penetrans HF-2 strain, was determined. The HF-2 genome consists of a 1 358 633 bp single circular chromosome containing 1038 predicted coding sequences (CDSs), one set of rRNA genes and 30 tRNA genes. Among the 1038 CDSs, 264 predicted proteins are common to the Mycoplasmataceae sequenced thus far and 463 are M.penetrans specific. The genome contains the two-component system but lacks the essential cellular gene, uridine kinase. The relatively large genome of M.penetrans HF-2 among mycoplasma species may be accounted for by both its rich core proteome and the presence of a number of paralog families corresponding to 25.4% of all CDSs. The largest paralog family is the p35 family, which encodes surface lipoproteins including the major antigen, P35. A total of 44 genes for p35 and p35 homologs were identified and 30 of them form one large cluster in the chromosome. The genetic tree of p35 paralogs suggests the occurrence of dynamic chromosomal rearrangement in paralog formation during evolution. Thus, M.penetrans HF-2 may have acquired diverse repertoires of antigenic variation-related genes to allow its persistent infection in humans.

Heat shock protein of Mycoplasma salivarium and Mycoplasma orale strains isolated from HIV-seropositive patients

It has been suggested that infection by some mycoplasma species can act as possible cofactors in the acceleration of immunodeficiency in HIV-infected patients. The present study was designed to examine infections by oral mycoplasma species in HIV-seropositive (HIV(+)) patients. Mycoplasma salivarium and Mycoplasma orale were isolated from 59.5% and 16.7% of 42 HIV(+) patients, respectively. Non-M. salivarium and non-M. orale species were isolated from 40.5% of saliva samples from the HIV(+) group and 20.8% of those from 24 HIV-seronegative (HIV(-)) subjects, respectively. Although the production of superantigen by human peripheral lymphocytes in the isolated mycoplasma species from HIV(+) and HIV(-) subjects was evaluated, none of the examined mycoplasma strains, including ATCC strains of M. salivarium, M. orale, Mycoplasma buccae and Mycoplasma penetrans, were found to produce superantigen. Production of heat shock proteins (HSPs) by isolated mycoplasma strains was examined by immunoblotting using monoclonal antibodies against Helicobacter pylori HSP60. It was found that all the strains of M. salivarium, M. orale, and unidentified mycoplasma species isolated from HIV(+) and HIV(-) groups produced heat shock proteins. HSP production by oral mycoplasma may play a role in the immunomodulation of HIV(+) patients.

Higher prevalence of urogenital mycoplasmas in human immunodeficiency virus-positive patients as compared to patients with other sexually transmitted diseases

We determined the prevalence of three emergent urogenital mycoplasma species (M. fermentans, M. penetrans, and M. genitalium) in comparison to the most common species (M. hominis and U. urealyticum). M. genitalium is probably the third most frequent agent of nongonococcal urethritis (NGU) in men. It has been suggested that M. fermentans and M. penetrans play a role in the development of AIDS. We analysed the urine and the urethral swab samples from 106 HIV-1 infected individuals (HIV group) and 110 HIV-negative patients with NGU (STD group) by using PCR and culture methods. M. genitalium was detected in 0.9% of the urine and in 1.9% of the urethral samples from the HIV group, compared to 9.1% found only in urethral swab samples from the STD group. M. fermentans was detected in 5.7% urethral swabs from the HIV group and in 0.9% from the STD group. M. penetrans was detected in 6.6% urine samples from the HIV group. M. hominis and U. urealyticum showed infection rates of 7.5 and 18.9% in the HIV group, and 0.9 and 13.6% in the STD group. Overall there was a higher prevalence of mycoplasmas in the HIV group than in the STD group, but the significance of these results remains unclear.