Bordetella pertussis isolation in general practice: 1977–79 whooping cough epidemic in West Glamorgan

Abstract

SUMMARYSome of the factors influencing the isolation rate of Bordetella pertussis during a whooping cough epidemic in West Glamorgan, Wales, are reported. The organism was isolated from 39 % ofpatients with clinical whooping cough, pernasal swabbing being much more successful than cough plates. Isolation rates were increased in the non-immunized, particularly in the first year of life. Erythromycin and co-trimoxazole significantly reduced the isolation rate of B. pertussis but this did not occur with penicillin. In this study 200 of patients were culture positive 6 weeks after the onset of their infection. It is suggested that the Department of Health and Social Security recommendation of a minimum period of three weeks exclusion ofchildren from school is inadequate. During the epidemic, the proportion of strains of B. pertussis containing antigen 2 more than doubled.

Pertussis: Microbiology, Disease, Treatment, and Prevention

“…Antimicrobial agents are recommended to clear the nasopharynx of B. pertussis and to prevent the spread of the infection (332,336,337). It was estimated that 80% to 90% of patients with untreated pertussis will clear B. pertussis from the nasopharynx within 3 to 4 weeks after the onset of cough (338). However, infants with pertussis who were not treated or vaccinated showed positive culture for more than 6 weeks (339).…”

Laboratory diagnosis of pertussis: state of the art in 1997

“…Experience with the method is one of the most important variables. Attempts at isolating B. pertussis are most likely to be successful at the end of the incubation period, during the catarrhal stage, and at the beginning of the paroxysmal (convulsive) stage of the disease (9,26,42,52,59,102). Isolation rates are negatively correlated with increasing age (high rate in infants [121]; low rate in adults [116]), with effective antimicrobial pretreatment (macrolides, co-trimoxazole, and tetracyclines but not penicillin or ampicillin [8,42,59,102]), and with the number of pertussis vaccination doses received by the patient (lower isolation rate in completely vaccinated individuals [8,35,59,102]).…”

Issues Associated with and Recommendations for Using PCR To Detect Outbreaks of Pertussis

“…Isolation of B. pertussis in culture, the traditional diagnostic standard for pertussis, has nearly 100% specificity and is widely used (9,19,25). However, because B. pertussis is fastidious, the sensitivity of culture can vary greatly and is dependent on the stage of illness at the time of specimen collection, the technique used for specimen collection, specimen adequacy and transport, and culture conditions.…”

“…However, because B. pertussis is fastidious, the sensitivity of culture can vary greatly and is dependent on the stage of illness at the time of specimen collection, the technique used for specimen collection, specimen adequacy and transport, and culture conditions. Under ideal conditions, the typical culture positivity rate can be greater than 50%; however, the rate is usually lower because of the reasons given above, as well as prior pertussis vaccinations, concurrent antibiotic therapy, and long elapsed time (e.g., more than 3 weeks) since cough onset (13,19,24,30). Seven to ten days may be required to isolate and confirm B. pertussis, precluding rapid culture confirmation (17).…”