Age- and serogroup-related differences in observed durations of nasopharyngeal carriage of penicillin-resistant pneumococci

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Age- and serogroup-related differences in observed durations of nasopharyngeal carriage of penicillin-resistant pneumococci. / Hogberg, Liselotte; Geli, Patricia; Ringberg, Håkan; Melander, Eva; Lipsitch, Marc; Ekdahl, Karl.

In: Journal of Clinical Microbiology, Vol. 45, No. 3, 2007, p. 948-952.

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Hogberg, Liselotte ; Geli, Patricia ; Ringberg, Håkan ; Melander, Eva ; Lipsitch, Marc ; Ekdahl, Karl. / Age- and serogroup-related differences in observed durations of nasopharyngeal carriage of penicillin-resistant pneumococci. In: Journal of Clinical Microbiology. 2007 ; Vol. 45, No. 3. pp. 948-952.

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TY - JOUR

T1 - Age- and serogroup-related differences in observed durations of nasopharyngeal carriage of penicillin-resistant pneumococci

AU - Hogberg, Liselotte

AU - Geli, Patricia

AU - Ringberg, Håkan

AU - Melander, Eva

AU - Lipsitch, Marc

AU - Ekdahl, Karl

PY - 2007

Y1 - 2007

N2 - Using data from an ongoing Swedish intervention project, the observed durations of nasopharyngeal carriage of penicillin-nonsusceptible Streptococcus pneumoniae (PNSP) (MIC of penicillin G of >= 0.5 mu g/ml) stratified by both pneumococcal serogroup and age of the carrier were compared. The means and 95% confidence intervals (CIs) were estimated by fitting a gamma distribution to the observed duration of carriage for each age and serogroup stratum. The mean observed duration of carriage for all cases was 37 days (95% CI, 35 to 38 days). Children below the age of 5 years carried PNSP for significantly longer periods (43 days; 95% CI, 41 to 45 days) compared with older individuals (25 days; 95% CI, 24 to 27 days). There were also differences within the group of cases below the age of 5 years, as the duration of carriage became significantly shorter for each increasing age step: < 1, 1 to 2, and 3 to 4 years. In addition, patients < 5 years of age carried serogroups 9 and 14 for significantly shorter periods than groups 6 and 23. Serogroup 9 was also carried for significantly shorter periods than group 19. For patients aged 5 years or older, no significant difference in carriage duration for different ages or serogroups could be noted. As young children have the longest duration of PNSP carriage, interventions aiming to reduce the prevalence in this group are of great importance. The results highlight the importance of taking both serogroup and age of the carriers into account when studying the dynamics of pneumococcal transmission in young children.

AB - Using data from an ongoing Swedish intervention project, the observed durations of nasopharyngeal carriage of penicillin-nonsusceptible Streptococcus pneumoniae (PNSP) (MIC of penicillin G of >= 0.5 mu g/ml) stratified by both pneumococcal serogroup and age of the carrier were compared. The means and 95% confidence intervals (CIs) were estimated by fitting a gamma distribution to the observed duration of carriage for each age and serogroup stratum. The mean observed duration of carriage for all cases was 37 days (95% CI, 35 to 38 days). Children below the age of 5 years carried PNSP for significantly longer periods (43 days; 95% CI, 41 to 45 days) compared with older individuals (25 days; 95% CI, 24 to 27 days). There were also differences within the group of cases below the age of 5 years, as the duration of carriage became significantly shorter for each increasing age step: < 1, 1 to 2, and 3 to 4 years. In addition, patients < 5 years of age carried serogroups 9 and 14 for significantly shorter periods than groups 6 and 23. Serogroup 9 was also carried for significantly shorter periods than group 19. For patients aged 5 years or older, no significant difference in carriage duration for different ages or serogroups could be noted. As young children have the longest duration of PNSP carriage, interventions aiming to reduce the prevalence in this group are of great importance. The results highlight the importance of taking both serogroup and age of the carriers into account when studying the dynamics of pneumococcal transmission in young children.

U2 - 10.1128/JCM.01913-06

DO - 10.1128/JCM.01913-06

M3 - Article

VL - 45

SP - 948

EP - 952

JO - Journal of Clinical Microbiology

JF - Journal of Clinical Microbiology

SN - 1098-660X

IS - 3

ER -