UPDATE ON INFECTIOUS DISEASE

Investigators concluded that the most reasonable protocol is to screen on the basis of risk factors on the same day as IUD insertion. If the patient has obvious evidence of endocervicitis (ie, mucopurulent discharge), IUD insertion should be delayed. Otherwise, if the patient has risk factors for infection, screening should be followed by IUD insertion.

If the screen is positive, the patient should be treated in accordance with the latest CDC recommendations, and the IUD can be left in place.

Sufrin and colleagues concluded that adherence to this protocol would be associated with a very low, and clinically acceptable, risk of PID.

STI screening need not be an obstacle to IUD use

The IUD is an excellent method of contraception, and it is suitable for most patients. It is particularly useful for women who have difficulty remembering to take a pill each day or to use a barrier method of contraception at each episode of coitus.

Obstacles to more widespread use of the IUD include:

• high initial cost
• misconceptions on the part of the patient about the mechanism of action and adverse effects of the device
• cumbersome protocols that require multiple physician visits for counseling and sexually transmitted infection (STI) testing before the device is inserted.

What this EVIDENCE means for practice
This study provides reassurance that, at least in a relatively affluent managed-care population, universal testing for STIs is probably not necessary. When testing is indicated, it can be performed on the same day that the IUD is inserted, minimizing the number of office visits.

What is less clear is whether the same protocol can be applied to a population with a significantly higher prevalence of STIs. In such a population, universal screening for gonorrhea and chlamydia may be more prudent. However, screening still can be performed on the same day as IUD insertion.

In a primate model of intra-amniotic infection with Ureaplasma, maternal azithromycin prolonged gestation

Grigsby PL, Novy MJ, Sadowsky DW, et al. Maternal azithromycin therapy for Ureaplasma intraamniotic infection delays preterm delivery and reduces fetal lung injury in a primate model. Am J Obstet Gynecol. 2012;207(6):475.e1–e14.

Grigsby and colleagues assessed the efficacy of azithromycin—with and without anti-inflammatory agents—in delaying preterm birth and minimizing fetal lung injury in a primate model. They found that azithromycin significantly prolonged gestation.

Details of the study

The study involved 16 chronically instrumented rhesus monkeys who received intra-amniotic inoculation with Ureaplasma parvum (10⁷ colony-forming units/mL) and were then observed. When contractions began, as they invariably did, six monkeys received no treatment, five received intravenous (IV) azithromycin (12.5 mg/kg every 12 hours) for 10 days, and five received azithromycin plus dexamethasone and indomethacin.

Key outcome measures were the intra-amniotic concentration of proinflammatory mediators, the frequency of positive amniotic fluid cultures for U parvum, and the extent of histologic fetal lung injury.

In treated animals, the mean (SD) inoculation-to-delivery interval was 20.9 (1.4) days, compared with 13.7 (2.5) days in untreated monkeys (P <.05).

In addition, there was a twofold to threefold increase in the percentage of undelivered animals at 18 to 20 days after inoculation in the treatment group, compared with the no-treatment group. Treatment also significantly decreased the Ureaplasma colony count in the amniotic fluid, effectively eliminating the organism within 4 days.

In both treatment groups, the amniotic fluid concentration of proinflammatory mediators decreased significantly, compared with the untreated group. Treatment also significantly reduced the magnitude of deleterious histologic changes in the fetal lungs.

Somewhat surprisingly, dexamethasone and indomethacin did not enhance the treatment effect of azithromycin. Moreover, despite prolongation of pregnancy, all animals in the treatment group still delivered prematurely.

Why treatment should target genital mycoplasmas

Chorioamnionitis is an importance cause of preterm labor and preterm delivery. The principal pathogens are part of the normal vaginal flora: aerobic Gram-negative bacilli, aerobic Gram-positive cocci, anaerobes, and genital mycoplasmas.

Most treatment regimens for chorioamnionitis (eg, ampicillin plus gentamicin) do not specifically target the genital mycoplasmas. However, the most commonly recommended prophylactic antibiotic regimens for patients with preterm PROM include agents with specific action against mycoplasmas, namely erythromycin and azithromycin.

In this clinical setting, antibiotic prophylaxis prolongs the latency period and decreases the frequency of both maternal and fetal/neonatal infection.

This elegant basic science investigation sheds new light on the importance of the genital mycoplasmas in the pathogenesis of preterm labor and helps to explain why drugs like erythromycin and azithromycin may be so valuable in prolonging the latent period and reducing the frequency of infection and injury in the baby.

What this EVIDENCE means for practice
Because IV azithromycin rapidly achieved inhibitory concentrations in amniotic fluid and maintained these concentrations over 10 days of treatment, it significantly reduced the concentration of Ureaplasma in the amniotic fluid as well as the risk of histologic injury to the fetal lung.

Accordingly, I recommend that azithromycin remain a key component of the prophylactic regimen for patients with preterm PROM. It also may be advisable to add azithromycin to the usual combination of ampicillin plus gentamicin for empiric treatment of chorioamnionitis.