880. Molecular Subtyping and Macrolide-Resistance Determination of Mycoplasma pneumoniae from Children Enrolled in New Vaccine Surveillance Network in the United States during 2015 to 2020

Abstract Background Mycoplasma pneumoniae (MP), a common pediatric pneumonia pathogen, has 2 subtypes based on P1 adhesin gene variation. Macrolide-resistant MP (MRMP), seen since 2000 in many countries, has been subtype associated. Limited U.S. pediatric data exist on MP subtype or MRMP frequency and their clinical importance. Methods During 2015–2020, mid-turbinate nasal swab (MTNS) specimens and/or throat swabs were collected from children with acute respiratory illness (ARI) enrolled in emergency department (ED) or outpatient and inpatient settings at 4 CDC-funded New Vaccine Surveillance Network sites (Cincinnati, Seattle, Houston, and Kansas City). Specimens were tested for MP and common respiratory viruses by singleplex or multiplex polymerase chain reaction assay (PCR). P1-subtyping for MP positive specimens used multiplex TaqMan real-time PCR while MR was assessed by real time PCR with melt curve analysis (Lightmix®, TIBMolbiol). Select demographic/clinical data were analyzed by P1 subtype (P1–1 vs. P1–2). Results Of 208 MTNS specimens from 208 children (median age 5.5 years), 110 (53%) were P1–1, 89 (43%) P1–2, and 9 (4%) untypeable. Of 199 typeable specimens, 111 (56%) came from inpatients while 88 (44%) came from ED/outpatients.Overall MRMP prevalence during 2015–2020 was low (3/208,1.4%); all MRMP (Houston: 1 each in 2016–2017 and 2019–2020, Seattle: 1 in 2018–2019) were P1–1. Differences in P1–2 vs. P1–1 proportions were significant in 2 years: P1–2 dominated in 2015–2016; P1-1 in 2019–2020 (Figure 1). Common clinical symptoms for 199 MP-positive patients were fever (84%, mean 102.5±1.5oF), shortness of breath (82%), wheezing (67%), and cough (60%). Clinical manifestations, hospitalization, and antibiotic use did not differ in P1-1 vs. P1-2 patients. Antibiotics were used in 59/199 (30%) patients overall; amoxicillin was most frequent (48/199, 24%), followed by cefdinir (9/199, 5%) and azithromycin (5/199, 3%). Conclusion MP subtypes co-circulated during 2015–2020; P1-2 dominated in 2015–2016, P1-1 in 2018–2019. Signs/symptoms were similar for P1-1 and P1-2. MRMP detection was uncommon among our pediatric subjects. Ongoing surveillance is important to assess potential changes in MR prevalence and temporal subtype variation. Disclosures Christopher J Harrison, MD, Astellas: Grant/Research Support|GSK: Grant/Research Support|Merck: Grant/Research Support|Pediatric news: Honoraria|Pfizer: Grant/Research Support Brian R. Lee, PhD, MPH, CDC: Grant/Research Support|Merck: Grant/Research Support Mary E. Moffatt, M.D., Becton and Dickinson and Company: Stocks/Bonds|Biogen: Stocks/Bonds|Coloplast B: Stocks/Bonds|Express Scripts: Stocks/Bonds|Novo Nordisk A/S Spons ADR: Stocks/Bonds|Novo Nordisk A/S-B: Stocks/Bonds|Steris PLC: Stocks/Bonds|Stryker Corp: Stocks/Bonds|Thermo Fisher Scientific: Stocks/Bonds Janet A. Englund, MD, Astra Zeneca: Advisor/Consultant|Astra Zeneca: Grant/Research Support|GlaxoSmithKline: Grant/Research Support|Meissa Vaccine: Advisor/Consultant|Merck: Grant/Research Support|Pfizer: Grant/Research Support|SanofiPasteur: Advisor/Consultant.