#117 – Amnio-Oh-No You Didn’t: Modernizing Antimicrobial Regimens for Intraamniotic Infections

Drs. Amy Crockett (@amyhcrockett), Ben Ereshefsky (@brainofbpharm), and Pamela Bailey (@pamipenem) join Dr. Julie Ann Justo (@julie_justo) to discuss new treatment strategies for management of intraamniotic infections, also known as chorioamnionitis. They discuss whether it is time to move away from the combination of ampicillin, gentamicin, and/or clindamycin, alternative antibiotic regimens to consider, and stewardship strategies to approach this practice change at a local level.

References:

1. Basic stats/epi on chorioamnionitis: Romero R, et al. Clinical chorioamnionitis at term I: microbiology of the amniotic cavity using cultivation and molecular techniques. J Perinat Med. 2015 Jan;43(1):19-36. doi: 10.1515/jpm-2014-0249. PMID: 25720095.
2. ACOG 2017 Guideline for IAI: Committee Opinion No. 712: Intrapartum Management of Intraamniotic Infection. Obstet Gynecol. 2017 Aug;130(2):e95-e101. doi: 10.1097/AOG.0000000000002236. PMID: 28742677.
3. ACOG 2024 Update on clinical criteria for IAI: ACOG Clinical Practice Update: Update on Criteria for Suspected Diagnosis of Intraamniotic Infection. Obstetrics & Gynecology 144(1):p e17-e19, July 2024. doi: 10.1097/AOG.0000000000005593
4. Helpful review with more recent microorganisms : Jung E, et al. Clinical chorioamnionitis at term: definition, pathogenesis, microbiology, diagnosis, and treatment. Am J Obstet Gynecol. 2024 Mar;230(3S):S807-S840. doi: 10.1016/j.ajog.2023.02.002. PMID: 38233317.
5. Cochrane Review: Chapman E, et al. Antibiotic regimens for management of intra-amniotic infection. Cochrane Database Syst Rev. 2014 Dec 19;2014(12):CD010976. doi: 10.1002/14651858.CD010976.pub2. PMID: 25526426.
6. Helpful recent review on intrapartum infections: Bailey, P, et al_._ Out with the Old, In with the New: A Review of the Treatment of Intrapartum Infections. Curr Infect Dis Rep. 2024;26:107–113 doi: 10.1007/s11908-024-00838-8.
7. Role of genital mycoplasmas in IAI: Romero R, et al. Evidence that intra-amniotic infections are often the result of an ascending invasion - a molecular microbiological study. J Perinat Med. 2019 Nov 26;47(9):915-931. doi: 10.1515/jpm-2019-0297. PMID: 31693497.
8. Regimens without enterococcal coverage with similar clinical outcomes: Blanco JD, et al. Randomized comparison of ceftazidime versus clindamycin-tobramycin in the treatment of obstetrical and gynecological infections. Antimicrob Agents Chemother. 1983 Oct;24(4):500-4. doi: 10.1128/AAC.24.4.500. PMID: 6360038.
9. Bookstaver PB, et al. A review of antibiotic use in pregnancy. Pharmacotherapy. 2015 Nov;35(11):1052-62. doi: 10.1002/phar.1649. PMID: 26598097.
10. Updated review in pregnancy, includes data on frequency of antibiotic use in pregnancy: Nguyen J, et al. A review of antibiotic safety in pregnancy-2025 update. Pharmacotherapy. 2025 Apr;45(4):227-237. doi: 10.1002/phar.70010. Epub 2025 Mar 19. PMID: 40105039.
11. Locksmith GJ, et al. High compared with standard gentamicin dosing for chorioamnionitis: a comparison of maternal and fetal serum drug levels. Obstet Gynecol. 2005 Mar;105(3):473-9. doi: 10.1097/01.AOG.0000151106.87930.1a. PMID: 15738010.
12. Clindamycin CDI Risk: Miller AC, et al. Comparison of Different Antibiotics and the Risk for Community-Associated Clostridioides difficile Infection: A Case-Control Study. Open Forum Infect Dis. 2023 Aug 5;10(8):ofad413. doi: 10.1093/ofid/ofad413. PMID: 37622034.
13. Impact of penicillin allergy on clindamycin use & cites 47% clindamycin resistance per CDC among GBS: Snider JB, et al. Antibiotic choice for Group B Streptococcus prophylaxis in mothers with reported penicillin allergy and associated newborn outcomes. BMC Pregnancy Childbirth. 2023 May 30;23(1):400. doi: 10.1186/s12884-023-05697-0. PMID: 37254067.
14. Clindamycin anaerobic coverage data: Hastey CJ, et al. Changes in the antibiotic susceptibility of anaerobic bacteria from 2007-2009 to 2010-2012 based on the CLSI methodology. Anaerobe. 2016 Dec;42:27-30. doi: 10.1016/j.anaerobe.2016.07.003. PMID: 27427465.
15. Older PK study of ampicillin & gentamicin for chorioamnionitis: Gilstrap LC 3rd, Bawdon RE, Burris J. Antibiotic concentration in maternal blood, cord blood, and placental membranes in chorioamnionitis. Obstet Gynecol. 1988 Jul;72(1):124-5. PMID: 3380500.
16. Paper putting out the call for modernization of OB/Gyn antibiotic regimens: Pek Z, Heil E, Wilson E. Getting With the Times: A Review of Peripartum Infections and Proposed Modernized Treatment Regimens. Open Forum Infect Dis. 2022 Sep 5;9(9):ofac460. doi: 10.1093/ofid/ofac460. PMID: 36168554.
17. Vanderbilt University Medical Center experience with modernizing OB/Gyn infection regimens: Smiley C, et al. Implementing Updated Intraamniotic Infection Guidelines at a Large Academic Medical Center. Open Forum Infect Dis. 2024 Sep 5;11(9):ofae475. doi: 10.1093/ofid/ofae475. PMID: 39252868.
18. Prisma Health/University of South Carolina experience with modernizing OB/Gyn infection regimens: Bailey P, et al. Cefoxitin for Intra-amniotic Infections and Endometritis: A Retrospective Comparison to Traditional Antimicrobial Therapy Regimens Within a Healthcare System. Clin Infect Dis. 2024 Jul 19;79(1):247-254. doi: 10.1093/cid/ciae042. PMID: 38297884.