Longitudinal Population Dynamics of Staphylococcus aureus in the Nasopharynx During the First Year of Life

Frontiers in Genetics

Mark P. Nicol¹  Felix Dube²  Polite M. Nduru³  Heather J. Zar³  Sugnet Gardner-Lubbe⁴  Jordache Ramjith⁵  Shima M. Abdulgader⁶  Lourens Robberts⁶ 

[1] Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa;Department of Molecular and Cell Biology, Faculty of Science, University of Cape Town, Cape Town, South Africa;Department of Paediatrics and Child Health, Red Cross War Memorial Children’s Hospital and SA-MRC Unit on Child and Adolescent Health, University of Cape Town, Cape Town, South Africa;Department of Statistics and Actuarial Science, Stellenbosch University, Stellenbosch, South Africa;Division of Epidemiology and Biostatistics, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa;Division of Medical Microbiology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa;;Institute of Infectious Disease &

关键词: Staphylococcus aureus;    carriage;    infancy;    genotype diversity;    longitudinal;   

DOI  :  10.3389/fgene.2019.00198

来源: DOAJ

【 摘 要 】

Background:Staphylococcus aureus colonization is a risk factor for invasive disease. Few studies have used strain genotype data to study S. aureus acquisition and carriage patterns. We investigated S. aureus nasopharyngeal carriage in infants in an intensively sampled South African birth cohort.Methods: Nasopharyngeal swabs were collected at birth and fortnightly from 137 infants through their first year of life. S. aureus was characterized by spa-typing. The incidence of S. aureus acquisition, and median carriage duration for each genotype was determined. S. aureus carriage patterns were defined by combining the carrier index (proportion of samples testing positive for S. aureus) with genotype diversity measures. Persistent or prolonged carriage were defined by a carrier index ≥0.8 or ≥0.5, respectively. Risk factors for time to acquisition of S. aureus were determined.Results: Eighty eight percent (121/137) of infants acquired S. aureus at least once. The incidence of acquisition at the species and genotype level was 1.83 and 2.8 episodes per child-year, respectively. No children had persistent carriage (defined as carrier index of >0.8). At the species level 6% had prolonged carriage, while only 2% had prolonged carriage with the same genotype. Carrier index correlated with the absolute number of spa-CCs carried by each infant (r = 0.5; 95% CI 0.35–0.62). Time to first acquisition of S. aureus was shorter in children from households with ≥5 individuals (HR 1.06, 95% CI 1.07–1.43), with S. aureus carrier mothers (HR; 1.5, 95% CI 1.2–2.47), or with a positive tuberculin skin test during the first year of life (HR; 1.81, 95% CI 0.97–3.3).Conclusion: Using measures of genotype diversity, we showed that S. aureus NP carriage is highly dynamic in infants. Prolonged carriage with a single strain occurred rarely; persistent carriage was not observed. A correlation was observed between carrier index and genotype diversity.

【 授权许可】

Unknown