Culture of Bordetella pertussis from three upper respiratory tract specimens

Laboratory Diagnosis of Pertussis

The introduction of vaccination in the 1950s significantly reduced the morbidity and mortality of pertussis. However, since the 1990s, a resurgence of pertussis has been observed in vaccinated populations, and a number of causes have been proposed for this phenomenon, including improved diagnostics, increased awareness, waning immunity, and pathogen adaptation. The resurgence of pertussis highlights the importance of standardized, sensitive, and specific laboratory diagnoses, the lack of which is responsible for the large differences in pertussis notifications between countries. Accurate laboratory diagnosis is also important for distinguishing between the several etiologic agents of pertussis-like diseases, which involve both viruses and bacteria. If pertussis is diagnosed in a timely manner, antibiotic treatment of the patient can mitigate the symptoms and prevent transmission. During an outbreak, timely diagnosis of pertussis allows prophylactic treatment of infants too young to be (fully) vaccinated, for whom pertussis is a severe, sometimes fatal disease. Finally, reliable diagnosis of pertussis is required to reveal trends in the (age-specific) disease incidence, which may point to changes in vaccine efficacy, waning immunity, and the emergence of vaccine-adapted strains. Here we review current approaches to the diagnosis of pertussis and discuss their limitations and strengths. In particular, we emphasize that the optimal diagnostic procedure depends on the stage of the disease, the age of the patient, and the vaccination status of the patient.

Pulmonary disorders in the training room

For the athlete, not only can pulmonary disorders cause significant alterations in training schedules or even prolonged stoppages, they can be life-threatening. Infectious diseases such as acute bronchitis, influenza, and pneumonia conspire to disrupt exercise regimens. Pneumothorax, vocal cord dysfunction, and exercise-induced asthma may present diagnostic and treatment challenges. Obstructive sleep apnea not only causes disruptive symptoms but can be associated with significant cardiovascular morbidity and even mortality. This article addresses the most common pulmonary conditions athletes face and provides a framework for the diagnosis and treatment of these conditions.

Nasopharyngeal colonization by Haemophilus influenzae in children living in an orphanage

AIM

To study colonization and transmission of Haemophilus influenzae in a cohort of children <2 years old living in the unique epidemiologic conditions of a closed community of an orphanage.

METHODS

Fifty-three children, ages 0 to 24 months, were followed for 1 year. All children >2 months were vaccinated against H. influenzae serotype b. Nasopharyngeal cultures were collected monthly or, in children <6 months of age, every 2 weeks. Antibiotic susceptibility, serotype, biotype and genotype (pulsed field gel electrophoresis) of each isolate were determined. As control, 39 H. influenzae isolates were recovered from various regions in France.

RESULTS

The mean monthly rate of carriage was 45% ranging from 17 to 70%. Most isolates belonged to biotype II (62%), 4 isolates to serotype f (3.6%) and none to serotype b, and 60% of the 111 isolates produced beta-lactamase. A complete concordance was found among biotype, serotype, pulsotype and antimicrobial susceptibility. On average children were sequentially colonized by 3 different isolates. The mean duration of carriage for a given isolate was approximately 1.4 months. In younger children the mean age of primary colonization was 2 months. Contrasting with the high genetic heterogeneity of 39 control isolates, most isolates (82%) belonged to only 5 pulsotypes. Three main H. influenzae clones rapidly spread in the community and colonized children in waves.

CONCLUSION

During early life nasopharyngeal colonization by H. influenzae is a dynamic phenomenon with sequential carriage of various clones spreading in the community.

Clinical and epidemiological aspects of respiratory syncytial virus lower respiratory tract infections

This paper has analyzed respiratory syncytial virus lower respiratory tract infections in 201 hospitalized children. In children with wheezing, erythrocyte sedimentation rate (ESR) was significantly higher in those with pneumonia than with syndroma pertussis, while the white blood cell (WBC) count was significantly lower in patients with bronchitis than in those with bronchiolitis and syndroma pertussis. Bronchodilatators were applied in 75.6% and corticosteroids in 20% of patients. Ten patients were ventilated. Fatal disease outcome was observed in one infant. Twelve consecutive-year study of respiratory syncytial virus (RSV) infections showed that 27.3% of these diseases were bronchiolitis and pneumonia.