Figure 1. Polymerase chain reaction (PCR) detection of Mycoplasma penetrans in clinical samples. A. M. penetrans PCR genomic amplification with the primers MYCPENET-P and MYCPENET-N (7) and analyzed by electrophoresis in 2% agarose gel. Lysates from the following original samples: throat swab (lane 1); tracheal aspirate (lane 2); blood (lane 3); first blood subculture (HF-1 isolate) (lane 4); M. penetrans GTU-54-6A1 (lane 5), showing the amplification product of 407-bp; and negative control (lane 6). B. Southern blotting of the same material. Hybridization with the internal oligonucleotide (MYCPENET-S) probe confirmed the specific amplification of M. penetrans genetic sequences.

Figure 2. HF isolates belong to the species Mycoplasma penetrans. A. Comparison of protein patterns from the type strain of M. penetrans and the isolate HF-1. Mycoplasma cells were directly lysed with SDS (cell lysate), or antigens were extracted with the neutral detergent Triton X-114 (total extract). Antigens were further separated after partitioning between the aqueous and detergent phases. The two mycoplasmas compared are the M. penetrans type strain GTU-54-6A1 (GTU) and the isolate HF. B. Ultrastructural features of the M. penetrans isolates HF-1, HF-2 and HF-3. The HF isolates were passaged four times in SP-4 broth without antibiotics and processed for transmission electron microscopy (TEM). Ultrathin sections were stained with osmiun tetroxide and ruthenium red and observed by TEM. The three isolates show the typical elongated, flask-shaped morphology of M. penetrans, with the two divided internal compartments. The cytoplasm is limited by a single triple-layered unit membrane that is covered with capsular material.