Does Mycoplasma hominis Require Treatment?
Mycoplasma hominis requires treatment only in specific clinical contexts: symptomatic pregnant women with genital colonization, patients with extragenital invasive infections (septic arthritis, postpartum fever), and immunocompromised hosts, but asymptomatic colonization in non-pregnant individuals does not require treatment.
Clinical Context Determines Treatment Necessity
Pregnancy-Related Infections
Symptomatic pregnant women with M. hominis colonization should be treated, as this reduces rates of preterm labor (37.7% vs 44.1% in untreated) and neonatal respiratory complications (5.9% vs 12.8% in untreated) 1.
Treatment with clindamycin in symptomatic pregnant women at 25-37 weeks gestation showing signs of potential obstetric complications significantly improves outcomes 1.
M. hominis colonization is associated with bacterial vaginosis (BV), where it represents one of the anaerobic bacteria replacing normal Lactobacillus species 2, 3.
Azithromycin is first-line treatment for M. hominis in pregnancy when macrolide susceptibility is confirmed or unknown, though resistance patterns are emerging 4, 5.
Genital colonization with M. hominis predisposes to spontaneous abortion and low birth weight (40.7% of infected women delivered low birth weight infants) 6.
Asymptomatic Colonization
Asymptomatic M. hominis colonization in non-pregnant women does not require treatment, as it can be part of normal vaginal flora 2, 3.
Up to 50% of women with bacterial vaginosis (which includes M. hominis overgrowth) are asymptomatic and do not require treatment unless pregnant or symptomatic 7, 2.
Treatment of male sexual partners for M. hominis colonization is not recommended and does not prevent recurrence 7, 3.
Extragenital Invasive Infections
M. hominis septic arthritis requires antibiotic treatment, occurring primarily postpartum, in immunosuppressed hosts, or after urinary tract manipulation 8.
Diagnosis is often delayed because M. hominis grows slowly in routine culture media and infection is not initially suspected 8.
Appropriate therapy leads to good outcomes, though relapses and antibiotic resistance have been reported 8.
Antibiotic Selection and Resistance
First-Line Agents
Doxycycline, tetracycline, and pristinamycin show uniform susceptibility for both M. hominis and U. urealyticum and may be used for empirical therapy in non-pregnant individuals 6.
Clindamycin is effective for treatment during pregnancy when tetracyclines are contraindicated 1.
Emerging Resistance Patterns
Azithromycin-resistant M. hominis infections are increasingly common (9.87% prevalence in one study), showing cross-resistance to erythromycin, roxithromycin, and clarithromycin 5.
Azithromycin-resistant cervical mycoplasma infection significantly increases adverse pregnancy outcomes including spontaneous abortion, preterm birth, and stillbirth 5.
There is currently a lack of safe and effective alternative drug treatments for azithromycin-resistant M. hominis in pregnancy, representing a significant clinical challenge 5.
Key Clinical Pitfalls
Do not treat asymptomatic colonization outside of pregnancy, as M. hominis can be part of normal flora and treatment does not prevent recurrence 7, 2.
Do not assume routine bacterial cultures will detect M. hominis, as specialized culture media or molecular testing is required 8.
Do not treat sexual partners for M. hominis colonization, as this has not been shown to prevent recurrence in the index patient 7, 3.
Consider M. hominis in postpartum septic arthritis or fever, especially after urinary tract procedures, as delayed diagnosis is common 8.