背景:肺炎链球菌(Spn),流感嗜血杆菌(Hflu)和卡他莫拉氏菌(Mcat)鼻咽定植先于疾病的发病机制,并因环境和国家而异。我们试图评估定殖患病率,密度,儿童初级保健机构出生后6个月的Spn血清型和抗生素耐药性。
方法:罗切斯特的前瞻性队列研究,纽约2018-2020年。收集了101名1、2和3周龄儿童的鼻咽拭子,然后1、2、4、6、9、12、15、18和24个月。Spn血清型由Quellung测定。测试了Hflu和Mcat对Spn和β-内酰胺酶生产的苯唑西林抗性。所有儿童根据美国推荐的时间表接种PCV13疫苗。
结果:Spn,Hflu和Mcat定植仅在2个月大之前的婴儿中检测到5%。Spn的累积患病率为34%,在=6个月大的儿童中,Hflu为10%,Mcat为53%。Spn的鼻咽细菌密度,Hflu和Mcat(x=2.71log)在=6个月的儿童中低于7-24个月的儿童(x=3.15log,p<0.0001)。检测到的=6月龄的主要血清型为23B(16.7%),22F(12.9%),15B/C(11%)和16F(9.2%)。14.8%的Spn分离株对苯唑西林耐药,66.7%的Hflu分离株产生β-内酰胺酶。
结论:Spn,在=6个月大的儿童中,Hflu和Mcat鼻咽定植并不常见,并且密度较低,尤其是2个月以下的儿童。与7-24月龄相比,在=6月龄中观察到非PCV13血清型占优势并且不同的血清型分布。
BACKGROUND: Streptococcus pneumoniae (Spn), Haemophilus influenzae (Hflu), and Moraxella catarrhalis (Mcat) nasopharyngeal colonization precedes disease pathogenesis and varies among settings and countries. We sought to assess colonization prevalence, density, Spn serotypes, and antibiotic resistance in children in the first 6 months of life in pediatric primary care settings.
METHODS: Prospective cohort study in Rochester, NY during 2018-2020. Nasopharyngeal swabs were collected from 101 children at age 1, 2, and 3 weeks, then 1, 2, 4, 6, 9, 12, 15, 18, and 24 months. Spn serotypes were determined by Quellung. Oxacillin resistance for Spn and β-lactamase production by Hflu and Mcat was tested. All children received PCV13 vaccine according to U.S. recommended schedule.
RESULTS: Spn, Hflu, and Mcat colonization was detected in only 5% of infants before age 2 months old. Cumulative prevalence was 34% for Spn, 10% for Hflu, and 53% for Mcat in children ≤6 months of age. Nasopharyngeal bacterial density of Spn, Hflu, and Mcat (x = 2.71 log) in children ≤6 months of age was lower than at 7-24 months of age (x = 3.15 log, p < 0.0001). Predominant serotypes detected ≤6 months of age were 23B (16.7%), 22F (12.9%), 15B/C (11%), and 16F (9.2%). In total, 14.8% of Spn isolates were oxacillin resistant and 66.7% of Hflu isolates were β-lactamase producing.
CONCLUSIONS: Spn, Hflu, and Mcat nasopharyngeal colonization was uncommon and of low density among children ≤6 months old, especially among children <2 months of age. Non-PCV13 serotypes predominated and a different serotype distribution was observed in ≤6-month olds compared to 7- to 24-month olds.