TY - JOUR
T1 - Marked difference between adults and children in Bordetella pertussis DNA load in nasopharyngeal swabs
AU - Nakamura, Y.
AU - Kamachi, K.
AU - Toyoizumi-Ajisaka, H.
AU - Otsuka, N.
AU - Saito, R.
AU - Tsuruoka, J.
AU - Katsuta, T.
AU - Nakajima, N.
AU - Okada, K.
AU - Kato, T.
AU - Arakawa, Y.
PY - 2011/3
Y1 - 2011/3
N2 - Bordetella pertussis is the aetiologic agent of whooping cough, a common cause of severe respiratory illness in children and prolonged mild cough in adults. To understand some of the reasons for differences in clinical symptoms between adults and children, we measured B. pertussis DNA loads in nasopharyngeal swabs (NPS) from 19 adults and 40 children (including 14 infants) by quantitative IS481 real-time PCR. All cases had been pre-diagnosed with the B. pertussis-specific loop-mediated isothermal amplification method. The mean PCR threshold cycles for adult and child NPS were 34.9 and 27.1, respectively, indicating a significantly lower B. pertussis DNA load in adults than in children (p<0.001). Moreover, adults had very low DNA loads during both early and later stages of the disease. When corresponding bacterial loads in NPS were calculated for B. pertussis Tohama cells using a standard curve, the mean number of bacterial cells taken with a rayon-tipped swab from an adult, older child and infant was estimated to be 320 (95% CI 120-910), 2.1×104 (95% CI 5.3×103 to 8.3×104) and 1.1×106 cells (95% CI 1.2×105 to 8.9×106), respectively. This indicates that the B. pertussis load in NPS is closely correlated with patient age. Our observations suggest that adult pertussis is characterized by a lower bacterial load in the nasopharynx, resulting in milder symptoms and negative cultures.
AB - Bordetella pertussis is the aetiologic agent of whooping cough, a common cause of severe respiratory illness in children and prolonged mild cough in adults. To understand some of the reasons for differences in clinical symptoms between adults and children, we measured B. pertussis DNA loads in nasopharyngeal swabs (NPS) from 19 adults and 40 children (including 14 infants) by quantitative IS481 real-time PCR. All cases had been pre-diagnosed with the B. pertussis-specific loop-mediated isothermal amplification method. The mean PCR threshold cycles for adult and child NPS were 34.9 and 27.1, respectively, indicating a significantly lower B. pertussis DNA load in adults than in children (p<0.001). Moreover, adults had very low DNA loads during both early and later stages of the disease. When corresponding bacterial loads in NPS were calculated for B. pertussis Tohama cells using a standard curve, the mean number of bacterial cells taken with a rayon-tipped swab from an adult, older child and infant was estimated to be 320 (95% CI 120-910), 2.1×104 (95% CI 5.3×103 to 8.3×104) and 1.1×106 cells (95% CI 1.2×105 to 8.9×106), respectively. This indicates that the B. pertussis load in NPS is closely correlated with patient age. Our observations suggest that adult pertussis is characterized by a lower bacterial load in the nasopharynx, resulting in milder symptoms and negative cultures.
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U2 - 10.1111/j.1469-0691.2010.03255.x
DO - 10.1111/j.1469-0691.2010.03255.x
M3 - Article
C2 - 20456454
AN - SCOPUS:78649853330
SN - 1198-743X
VL - 17
SP - 365
EP - 370
JO - Clinical Microbiology and Infection
JF - Clinical Microbiology and Infection
IS - 3
ER -
