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.

Prevalence of Eperythrozoon spp. infection and congenital eperythrozoonosis in humans in Inner Mongolia, China.

Eperythrozoon is an obligate parasitic bacteria found in many species of animals. A large scale investigation of the prevalence of Eperythrozoon spp. in humans, was conducted in a developing country using light, electron microscope and animal inoculation. Samples were collected in undeveloped areas of Inner Mongolia in China over a 2-year period of 1994-6. Of the 1529 investigated samples, 35.3% were found to be Eperythrozoon spp. positive. The prevalence of infection was associated with occupation and seasonal variations. The infections were mainly mild, in 89.6% of cases (excluding pregnant women and their children). Of 74 pregnant women tested in the areas of high prevalence, 44 were confirmed Eperythrozoon spp. positive. Similarly, eperythrozoa were found in all 44 umbilical cords tested and in the neonatal peripheral blood samples taken at birth. These data suggest that eperythrozoa can be transmitted via the placenta.

[The immunological consequences of congenital infections]. / Immunologicheskie posledstviia vrozhdennykh infekstii.

Mice of different strains were inoculated with type A influenza virus or Mycoplasma arthritidis in the second half of pregnancy. A part of the animals born after this inoculation were characterized by a sharp retardation of growth. The study of the immune status of such animals revealed that their proliferative response to mitogenic/superantigenic factors of the infective agents introduced during pregnancy was suppressed or absent, and the cells of their immune system began to recognize syngeneic intact stimulators in the mixed lymphocytes culture as heterogeneous ones. The spleen of the experimental animals was found to contain suppressor cells, both specific and nonspecific with respect to the infective agent. After inoculation with M. arthritidis areactivity was observed only in mice, sensitive to mycoplasmal superantigen. The data thus obtained suggest that the penetration of infecting agents producing mitogenic/superantigenic factors induced changes in the immune system, contributing to the persistence of the infective agent in the host body.

Mycoplasma hominis in maternal and fetal infections.

Although prevalence of M. hominis colonization during pregnancy varies from 12-50%, its role in infections of the mother and newborn infants is unclear. Definite correlations exist with chorioamnionitis and amniotic fluid infections, but as it is rarely isolated alone during these infections, its pathogenic role is uncertain. Its association with septic abortion is similarly questioned. Prevalence and antibody titers to M. hominis increase with increasing parity. Transient bacteremia occurs in approximately 2.5% of normal deliveries. M. hominis does have a significant role in postpartum fever. Women harboring the organism during labor with low predelivery antibody titers are at risk. Approximately 30% of exposed infants are colonized (4% of all infants) but there are only a few reports of neonatal meningitis, pneumonia, or skin abscesses due to M. hominis. Most recover without specific therapy. The role of antimicrobial therapy of M. hominis in pregnancy and the neonatal period is unclear. Further studies of these issues should simultaneously consider all potential genital tract pathogens.

Maternal and infant sexually transmitted diseases.

Sexually transmitted infection may result in serious damage to the reproductive tract of the mother, damage to the fetus, wastage of pregnancy, or illness or death of the infant. The effects of gonorrhea, Chlamydia trachomatis infection, mycoplasmal infections, group B streptococcus infections, syphilis, and viral infections are discussed separately for both mother and infant.

The effect of experimental turkey embryo infection with Mycoplasma meleagridis on weight, weight gain, feed consumption, and conversion.

Turkey poults were obtained from an earlier trial where hatchability performance of a group of embryos experimentally infected with Mycoplasma meleagridis [MM(+)] was compared with that of a group of uninfected cohorts [MM(-)]. In the present trial, post-hatch production parameters compared were weight, weight gain, feed consumption, feed conversion, culling, and mortality. Both toms and hens were monitored for 16 weeks, and a group of randomly selected toms was monitored for 22 weeks. Final liveweights and dressweights of hens were compared at 17 weeks, and those of the toms were compared at 23 weeks. Hens showed no significant (P less than 0.05) differences in the measured parameters during the 16-week period, nor did the initial population of toms, except in weight gain during the final period (weeks 12-16) and in final weight at week 16, which were significantly (P less than 0.05) greater in the MM(+) toms than in their MM(-) cohorts. Dressweights at slaughter of MM(+) hens were significantly greater than those of MM(-) hens, but liveweights of hens at slaughter and both liveweights and dressweights of toms at slaughter did not differ significantly. This inability of MM(-) turkeys to demonstrate a comparative advantage over MM(+) birds agrees with an earlier trial (4), in which MM(+) poults had weights superior to those of MM(-) cohorts during the first 3 to 4 weeks of life (4). These data indicate that the theory of superior performance in association with MM(-) birds must be reevaluated before the benefits derived from an M. meleagridis eradication program can be measured.

Multiple birth defects in a newborn exposed to Mycoplasma pneumoniae in utero.

A newborn baby girl with progressive hydrocephalus and congenital defects of the skin and eyes was born to a mother who experienced bilateral bronchopneumonia in her first trimester. At the time of her infection, the mother's serum cold agglutinin titer was 1:128 and at delivery the mother's and baby's serum samples had complement-fixation titers to Mycoplasma pneumoniae of 1:1,024 and 1:256, respectively. At 1 week of age the baby's serum IgM value was 44 mg/100 ml (98% of cord IgM values in normal newborns range from 0 to 20 mg/100 ml). The baby died of progressive hydrocephalus, which may have had an inflammatory basis in view of the cerebrospinal fluid (CSF) protein level of 192 mg/100 ml. We realize that the significance of this association is questionable, but we believe that it is worthwhile to call the coincidence of events to the attention of others.