Detecção de Mycoplasma genitalium, M. fermentans e M. penetrans em pacientes com sintomas de uretrite e em indivíduos infectados pelo HIV-1 no Brasil

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Abstract

Neste trabalho investigamos a prevalência de três espécies de micoplasma recém-identificadas como patógenos humanos, M. genitalium, implicado em casos de uretrite não-gonocócica, e M. fermentans e M. penetrans, isolados de pacientes imunodeprimidos, e das duas espécies mais freqüentes no trato geniturinário, M. hominis e U. urealyticum. Foram estudados 110 pacientes com sintomas de uretrite (grupo A) e 106 indivíduos infectados pelo HIV-1 (grupo B). M. genitalium foi detectado em 10,9% das amostras de raspado uretral do grupo A, e em 1,9% das amostras de raspado uretral e 0,9% das amostras de urina do grupo B. M. fermentans foi detectado em 0,9% e 5,7% das amostras de raspado uretral dos grupos A e B, respectivamente. M. penetrans foi detectado em 6,6% das amostras de urina somente do grupo B. M. hominis e U. urealyticum tiveram taxas de infecção de 0,9% e 14,5% no grupo A, e de 7,5% e 18,9% no grupo B, respectivamente. A relevante prevalência da infecção por estas novas espécies, em comparação aos micoplasmas mais conhecidos do trato urogenital, sugere que a magnitude do papel destes microrganismos no âmbito das doenças sexualmente transmissíveis (DST) e da infecção pelo HIV pode estar sendo subestimada em nossa população.

Translated abstract

In this work the prevalence of three mycoplasma species recently identified as human pathogens was investigated: M. genitalium, involved in cases of non-gonococcal urethritis, and M. fermentans and M. penetrans, isolated from immunosupressed individuals, and the 2 species more frequently isolated from the urogenital tract: M. hominis and U. urealyticum. Studied groups were composed by 110 patients with symptoms of urethritis (group A) and 106 HIV-1-infected individuals (group B). M. genitalium was detected in 10.9% of the urethral swab samples from the group A, and in 1.9% of the urethral swab samples and 0.9% of the urine samples from the group B. M. fermentans was detected in 0.9% and 5.7% of the urethral swab samples from the groups A and B, respectively. M. penetrans was detected in 6.6% of the urine samples only from the group B. M. hominis and U. urealyticum presented infection rates of 0.9% and 14.5% in the group A, and of 7.5% and 18.9% in the group B, respectively. The relevant prevalence of infection by these new species, as compared to the better known mycoplasmas of the genitourinary tract, suggest that the role of these microorganisms in the field of STD and HIV infection may be underestimated in our population.

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Most cited references 51

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Molecular biology and pathogenicity of mycoplasmas.

S RAZIN, D Yogev, Y. Naot (1998)

The recent sequencing of the entire genomes of Mycoplasma genitalium and M. pneumoniae has attracted considerable attention to the molecular biology of mycoplasmas, the smallest self-replicating organisms. It appears that we are now much closer to the goal of defining, in molecular terms, the entire machinery of a self-replicating cell. Comparative genomics based on comparison of the genomic makeup of mycoplasmal genomes with those of other bacteria, has opened new ways of looking at the evolutionary history of the mycoplasmas. There is now solid genetic support for the hypothesis that mycoplasmas have evolved as a branch of gram-positive bacteria by a process of reductive evolution. During this process, the mycoplasmas lost considerable portions of their ancestors' chromosomes but retained the genes essential for life. Thus, the mycoplasmal genomes carry a high percentage of conserved genes, greatly facilitating gene annotation. The significant genome compaction that occurred in mycoplasmas was made possible by adopting a parasitic mode of life. The supply of nutrients from their hosts apparently enabled mycoplasmas to lose, during evolution, the genes for many assimilative processes. During their evolution and adaptation to a parasitic mode of life, the mycoplasmas have developed various genetic systems providing a highly plastic set of variable surface proteins to evade the host immune system. The uniqueness of the mycoplasmal systems is manifested by the presence of highly mutable modules combined with an ability to expand the antigenic repertoire by generating structural alternatives, all compressed into limited genomic sequences. In the absence of a cell wall and a periplasmic space, the majority of surface variable antigens in mycoplasmas are lipoproteins. Apart from providing specific antimycoplasmal defense, the host immune system is also involved in the development of pathogenic lesions and exacerbation of mycoplasma induced diseases. Mycoplasmas are able to stimulate as well as suppress lymphocytes in a nonspecific, polyclonal manner, both in vitro and in vivo. As well as to affecting various subsets of lymphocytes, mycoplasmas and mycoplasma-derived cell components modulate the activities of monocytes/macrophages and NK cells and trigger the production of a wide variety of up-regulating and down-regulating cytokines and chemokines. Mycoplasma-mediated secretion of proinflammatory cytokines, such as tumor necrosis factor alpha, interleukin-1 (IL-1), and IL-6, by macrophages and of up-regulating cytokines by mitogenically stimulated lymphocytes plays a major role in mycoplasma-induced immune system modulation and inflammatory responses.

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Record: found
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Genus- and species-specific identification of mycoplasmas by 16S rRNA amplification.

W. Melchers, Andries J van Tonder, J. M. D. GALAMA … (1992)

Systematic computer alignment of mycoplasmal 16S rRNA sequences allowed the identification of variable regions with both genus- and species-specific sequences. Species-specific sequences of Mycoplasma collis were elucidated by asymmetric amplification and dideoxynucleotide sequencing of variable regions, using primers complementary to conserved regions of 16S rRNA. Primers selected for Mycoplasma pneumoniae, M. hominis, M. fermentans, Ureaplasma urealyticum, M. pulmonis, M. arthritidis, M. neurolyticum, M. muris, and M. collis proved to be species specific in the polymerase chain reaction. The genus-specific primers reacted with all mycoplasmal species investigated as well as with members of the genera Ureaplasma, Spiroplasma, and Acholeplasma. No cross-reaction was observed with members of the closely related genera Streptococcus, Lactobacillus, Bacillus, and Clostridium or with any other microorganism tested. On the basis of the high copy number of rRNA, a highly sensitive polymerase chain reaction assay was developed in which the nucleic acid content equivalent to a single organism could be detected.