Mycoplasma

Mycoplasma species are unique bacteria that can cause various infections, particularly in the respiratory and urogenital tracts.
A cell wall and fastidious growth requirements are needed for laboratory identification.
Understanding their characteristics, pathogenic mechanisms, and effective diagnostic methods is essential for managing infections.
Public health education and awareness are important for preventing and controlling mycoplasma-related diseases.

Table of contents

Genus: Mycoplasma
Key Species:
- Mycoplasma pneumoniae (causes atypical pneumonia)
- Mycoplasma genitalium (associated with urogenital infections)
- Mycoplasma hominis (associated with pelvic inflammatory disease and other infections)
Family: Mycoplasmataceae
Gram Staining: Mycoplasma species do not have a cell wall, making them Gram-negative and resistant to standard Gram staining.
Shape and Arrangement:
- Shape: Pleomorphic; can appear as spherical, filamentous, or branched forms.
- Arrangement: Typically found as single cells but can form clusters.
Oxygen Requirements: Mycoplasma species are facultative anaerobes, some being strictly anaerobic.

Cell Wall Structure:
- Mycoplasma species lack a conventional cell wall, making them uniquely adaptable and vulnerable to osmotic pressure.
Membrane Structure: Their membranes contain sterols, which help maintain stability and integrity.

Growth Media:
- Mycoplasma species require specialized media for growth, such as Mycoplasma agar or PPLO (Pleuropneumonia-Like Organism) broth.
Colony Appearance:
- Colonies may appear as small, fried egg-shaped colonies on solid media.
Temperature and pH Range:
- The optimal growth temperature is typically around 37°C, with an ideal neutral pH.

Catalase Test: Mycoplasma species are catalase-positive.
Oxidase Test: Mycoplasma species are oxidase-negative.
Fermentation: Mycoplasma does not ferment carbohydrates; it requires preformed nutrients from the host or culture media.

Virulence Factors:
- Adhesins: Surface proteins allow attachment to host cells.
- Cytotoxic Effects: Mycoplasma can damage host cells and evade the immune response.
Clinical Infections:
- Mycoplasma pneumoniae:
  - Causes atypical pneumonia, often called “walking pneumonia,” characterized by a persistent cough, fever, and malaise. It commonly affects younger populations.
- Mycoplasma genitalium:
  - Associated with urethritis, cervicitis, and pelvic inflammatory disease. It can contribute to infertility.
- Mycoplasma hominis:
  - It can cause urogenital infections and has been implicated in postpartum infections and other complications.

Specimen Collection: Clinical specimens may include respiratory secretions, urine, or swabs from affected areas.
Microscopic Examination:
- Direct visualization is challenging due to lacking a cell wall; specialized staining methods may be used.
Culture Techniques:
- Inoculation in specialized media; growth may take several days to weeks.
Serological Testing:
- Serological tests can detect antibodies against Mycoplasma species but may not be specific.
Molecular Methods: PCR is increasingly used for rapid and specific detection of Mycoplasma DNA.

Emergence of Resistance: Mycoplasma species show inherent resistance to beta-lactam antibiotics due to the absence of a cell wall.
Treatment Options:
- Mycoplasma pneumoniae: Treatment typically includes macrolides (e.g., azithromycin) or tetracyclines (e.g., doxycycline).
- Mycoplasma genitalium: Often treated with azithromycin or moxifloxacin, though resistance patterns are emerging.

Hygiene Practices: Good hygiene and safe sexual practices can reduce the risk of Mycoplasma infections.
Public Health Measures: Education about transmission routes and symptoms can aid early detection and treatment.