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# Mycoplasma (Pathogen, not a drug)
## Overview
*Mycoplasma* are a genus of bacteria characterized by the absence of a cell wall. This makes them intrinsically resistant to many common antibiotics, such as penicillins and cephalosporins, which target cell wall synthesis.
## Primary Indications
*Mycoplasma* species can cause a variety of infections in humans, including:
* **Respiratory Tract Infections:** *Mycoplasma pneumoniae* is a common cause of community-acquired pneumonia (walking pneumonia) and bronchitis.
* **Genitourinary Infections:** Species like *Mycoplasma genitalium* and *Ureaplasma urealyticum* are associated with urethritis, pelvic inflammatory disease, and infertility.
## Adult Dosing
Treatment depends on the specific *Mycoplasma* species and the site of infection. Common antibiotic classes used include:
* **Macrolides:** e.g., Azithromycin, Clarithromycin.
* **Azithromycin:** 500 mg once on day 1, then 250 mg once daily for 4 days.
* **Clarithromycin:** 500 mg twice daily for 7-14 days.
* **Tetracyclines:** e.g., Doxycycline.
* **Doxycycline:** 100 mg twice daily for 7-14 days.
* **Fluoroquinolones:** e.g., Levofloxacin, Moxifloxacin.
* **Levofloxacin:** 500 mg once daily for 7-14 days.
* **Moxifloxacin:** 400 mg once daily for 7-14 days.
*Note: Dosing frequency and duration can vary based on clinical guidelines and the severity of infection. Resistance to macrolides is increasing, particularly for *M. pneumoniae*. Fluoroquinolones are often reserved for cases of macrolide resistance or intolerance.*
## Pediatric Dosing
Dosing for *Mycoplasma* infections in children should be guided by current pediatric infectious disease guidelines. Common agents and typical pediatric dosing considerations:
* **Azithromycin:** For *M. pneumoniae* pneumonia, typically 10 mg/kg on day 1 (maximum 500 mg), followed by 5 mg/kg on days 2-5 (maximum 250 mg/day).
* **Doxycycline:** Generally not recommended for children younger than 8 years due to potential tooth discoloration, unless no effective alternative exists and benefits outweigh risks. If used, dosing is typically 4.4 mg/kg/day divided into two doses.
## Dose Adjustments
* **Renal Impairment:** Most agents used (azithromycin, doxycycline, levofloxacin) require dose adjustments in severe renal impairment. Refer to specific drug monographs.
* **Hepatic Impairment:** Dose adjustments may be necessary for some agents, particularly macrolides and fluoroquinolones. Refer to specific drug monographs.
## Contraindications
* Hypersensitivity to the specific antibiotic.
* Contraindications specific to the chosen antibiotic class (e.g., QT prolongation risk with macrolides and fluoroquinolones in certain individuals, phototoxicity with tetracyclines).
## Adverse Effects
Adverse effects are related to the chosen antibiotic and can include:
* **Macrolides:** Gastrointestinal upset (nausea, vomiting, diarrhea), QT prolongation, liver enzyme elevations.
* **Tetracyclines:** Gastrointestinal upset, photosensitivity, tooth discoloration (in children < 8 years), esophageal irritation.
* **Fluoroquinolones:** Gastrointestinal upset, dizziness, headache, QT prolongation, tendonitis/tendon rupture, *Clostridioides difficile*-associated diarrhea, dysglycemia.
## Key Drug Interactions
Interactions are dependent on the chosen antibiotic. Examples:
* **Macrolides:** CYP3A4 inhibitors/inducers, drugs prolonging QT interval.
* **Tetracyclines:** Antacids, iron supplements, calcium, dairy products (reduce absorption).
* **Fluoroquinolones:** Antacids, iron, zinc, sucralfate, dairy products (reduce absorption); warfarin; theophylline; caffeine.
## Monitoring
* Clinical signs and symptoms of infection.
* Laboratory parameters as indicated by the chosen antibiotic (e.g., LFTs, renal function).
* Monitoring for adverse effects of the antibiotic.
* Consider drug resistance testing in cases of treatment failure, especially for macrolides.
## Clinical Pearls
* *Mycoplasma* infections can have a variable and prolonged course.
* Macrolide resistance is an emerging concern for *M. pneumoniae*. Consider doxycycline or a respiratory fluoroquinolone if macrolide therapy fails or if resistance is suspected/confirmed.
* Always confirm the causative pathogen and its susceptibility profile when available, especially for severe or persistent infections.
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**Disclaimer:** This information is intended for healthcare professionals and is not a substitute for professional medical advice. Always consult the most current prescribing information and relevant clinical guidelines before making any treatment decisions. Dosing may vary based on patient-specific factors, local protocols, and emerging resistance patterns.
