Abstract
Introduction. The Mollicutes class unites cell wall lacking bacteria many of which are membrane parasites and opportunistic bacteria.Aim. This study describes a novel morphological form found in the five species belonging to the bacterial class Mollicutes, and referred to as microcolonies (MCs).Methodology. MCs were obtained as described below and characterized with bacteriological and immunological methods, and microscopy.Results. In contrast to typical colonies (TCs), MCs are characterized by tiny propeller-shaped colonies formed by rod-like cells tightly packed in parallel rows. These colonies were observed within routinely cultivated cultures of type strains 7-12 days post-plating. Rod-like cells were visualized using a scanning electron microscope within TCs with a 'fried-egg-like' appearance. MCs were not observed to revert to TCs. MCs were resistant to antibiotics and other treatments effective against TCs. Pure MC cultures were generated in vitro by treatment of Mycoplasma cultures with hyperimmune serum, antibiotics or argon non-thermal plasma. MCs of Mycoplasma hominis strain H-34 were characterized in detail to confirm that they belonged to that species. MCs tested positive via PCR with M. hominis-specific primers, direct fluorescence and epifluorescence tests, and Western blotting with the camel-derived nanobody aMh-FcG2a, which is specific to the MH3620 transporter protein. Meanwhile, MCs behaved differently in standard bacteriological tests. Pure MC cultures were also isolated directly from clinical samples of the serum, synovial liquid and urine of patients within flammatory urogenital tract diseases, asthma or arthritis. In total, 79 independent MC cultures were isolated from clinical samples including M. hominis (n=70), Mycoplasma pneumoniae (n=2), Mycoplasma fermentans (n=2) and Mycoplasma spp. (n=5).Conclusion. MCs play an unknown role in infection pathology and display prominent antibiotic resistance, making them a challenge for the future studies on Mollicutes.
Highlights
Mycoplasma spp belong to the Mollicutes class that united cell wall lacking bacteria most of which are membrane parasites [1,2,3]
Some of Mycoplasma play role in development of autoimmune diseases such as asthma [9,10,11]. Mycoplasma spp when they are grown on the agar form colonies with the dense partly immersed in the agar center and delicate periphery, the morphology is known as “fried-egg”[12,13,14]
We had often observed positive signals when applied PCR to test serum samples. As these results suggested a M. hominis infection, we plated serum samples according to the procedure but we have never observed typical M. hominis colonies (TCs) in these conditions
Summary
Mycoplasma spp belong to the Mollicutes class that united cell wall lacking bacteria most of which are membrane parasites [1,2,3]. Some of Mycoplasma play role in development of autoimmune diseases such as asthma [9,10,11] Mycoplasma spp when they are grown on the agar form colonies with the dense partly immersed in the agar center and delicate periphery, the morphology is known as “fried-egg”[12,13,14]. These colonies that further we will call typical colonies (TCs) grow up to the full size within 48-72 h and have a diameter ranges from about 75 to 800 μm [15]. E.g. for isolates obtained from clinical samples, these time intervals increase
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