Attachment of Mycoplasma hominis and M. orale to human diploid lung fibroblasts

In vitro influence of Mycoplasma species on the stimulation of human polymorphonuclear granulocytes

The influence of Mycoplasma species (sp.) on the stimulation of human polymorphonuclear neutrophil granulocytes (PMNG) was determined by means of the luminol-dependent chemiluminescence (CL) method. When opsonized Mycoplasma sp. were used the CL response of PMNG was greater than in the presence of nonopsonized strains. Nonopsonized and nonspecifically opsonized Mycoplasma sp. showed a different CL response pattern. The stimulation of PMNG was with M. pneumoniae significantly weaker than with the other Mycoplasma sp. Using isolated M. hominis strains always the same CL-reaction of PMNG was observed. On the other hand, with 12 isolated U. urealyticum strains different results were obtained; 9 strains isolated from the upper urogenital tract lead to a slight PMNG stimulation comparable to that of M. pneumoniae. No correlation was found between CL response and bacterial killing. The weak stimulation of PMNG by M. pneumoniae and most of the U. urealyticum isolates suggest that this behaviour could be a factor of pathogenicity.

Invasiveness of Salmonella typhimurium in HEp-2 cell cultures pre-infected with Mycoplasma hominis and Mycoplasma orale

The influence of mycoplasma infection on the in vitro invasiveness of S. typhimurium in HEp-2 cell cultures has been tested. Two strains of arginine-utilizing mycoplasma species Mycoplasma hominis and M. orale both seemed to inhibit the bacterial in vitro invasiveness. Both the ratio of infected cells and the number of intracellular bacteria per cell were reduced in the mycoplasma-infected cultures.

Behavior of Mycoplasma hominis in a human diploid cell culture system

The behavior of Mycoplasma hominis in normal human embryonic lung fibroblast (HAIN-55) cell cultures was investigated. Multiplication patterns of cell-associated mycoplasmas and of extracellular mycoplasmas in the HAIN-55 cultures depended upon the size of the inoculum. This relationship did not vary with the number of days the cells had been cultured, nor with the number of HAIN-55 cell passages. The maximum mycoplasmal growth was obtained with inoculum sizes of 10(5) to 10(6) colony-forming units (CFU)/ml. The recovery of mycoplasmas decreased rapidly with inoculum size beyond 10(7) CFU/ml, and growth of the HAIN-55 cells was inhibited. Growth of the cells was also inhibited by the addition of the cytoplasmic fraction of Mycoplasma hominis.