Current pharmacotherapy of pertussis

Pharmacotherapy for Bordetella pertussis infection. I. A synthesis of laboratory sciences

There is considerable history and practice experience both with laboratory susceptibility testing for Bordetella pertussis and clinical treatment. This two-part narrative review provides a synthesis of the laboratory and clinical sciences as they apply to this bacterium and the clinical consequences of treating infection. It is generally held that antibiotic susceptibility testing for B. pertussis is not sufficiently standardised, but there has not been an urgent need to consolidate the same given the lack global experience with major resistance profiles. Experience in China, however, has provided concern for high-level macrolide resistance. The nature of and frequency of such resistance has raised the bar for reconsideration of susceptibility testing given that first-line treatment may be regionally compromised. Disk diffusion and Etest susceptibility testing can be recommended for screening resistance among individual isolates of B. pertussis and on an ad hoc manner. Disk diffusion, Etest and/or critical agar dilution testing can be recommended for large-scale studies. Standards for inoculum, growth atmosphere, timing of interpretation, preferred testing media and controls can be extrapolated from the publications to date. Such methods should be able to detect high-level resistance to several antibiotics, but especially macrolides. Concern for intermediate-susceptible categories requires consideration as well as the correlation with bacteriological and clinical outcomes. Provisional standards can be applied at this time, and modification or fine-tuning of any such standards are open to future investigation.

Pharmacotherapy for Bordetella pertussis infection. II. A synthesis of clinical sciences

Despite the plethora of studies that have examined laboratory susceptibility testing for Bordetella pertussis, assessments of treatment have lagged far behind both in quality and quantity. Macrolides and trimethoprim/sulfamethoxazole historically served the needs of both treatment and prevention, albeit there is still controversy about the degree of protection measured both bacteriologically and clinically. As high-level macrolide resistance has emerged in some geographic regions and since macrolides have been the mainstay of therapy, alternative antibiotics need to be defined for pertussis. In vitro susceptibility testing suggests the potential for several alternatives to macrolides, including trimethoprim/sulfamethoxazole, specific β-lactam agents, chloramphenicol, some quinolones and possibly some tetracyclines. For the latter antibiotics, more clinical studies for treatment and prophylaxis are required in to order to establish bacteriological-clinical correlates for outcome. In the interim, if the clinical circumstances mandate the use of proposed interim alternatives to macrolides, outcomes should be assessed with test of cure by culture, since genetic amplification technologies do not discriminate bacterial viability. Whereas there may be debate in regard to using placebo or macrolides as the controls for alternative antibiotic therapy in geographies where most B. pertussis isolates are antibiotic-susceptible, both placebo and macrolide controls should be assessed along with alternative antibiotics in well-designed controlled studies in regions pressured by macrolide resistance. Outcomes of clinical response and epidemiological patterns of disease should continue to be monitored given the degree of macrolide resistance that is emerging.

Does working in hospital increases seroprevalence and carrier state against Bordetella pertussis?

Background:

Health care environments have been the setting for a number of pertussis outbreaks. Immunity after vaccination wanes overtime leading to a growing population of susceptible adolescents and adults. A number of pertussis outbreaks have occurred in hospitals resulting in transmission to health care workers (HCWs), and other patients. The aim of this study was to assess immunity status of a group of basic medical students and interns who worked in hospitals for about 4 years.

Materials and Methods:

In a cross-sectional study, we measured the serum antibody titer of cases by enzyme-linked immunosorbent assay test. All 70 subjects have received pertussis vaccine in the routine childhood vaccination schedule. All cases were healthy and had no symptoms of any respiratory diseases. We also obtained a pharyngeal culture on Bordet-Gengou Agar for isolating Bordetella pertussis.

Results:

The results of B. pertussis pharyngeal culture was positive for 5 (7.1%) cases and negative for 65 (92.9%). The IgM, IgA, and IgG serum antibody was positive in 1.4%, 7.1%, and 11.4% of cases, respectively. The mean age of cases had no significant effect on serum antibody titers (P = 0.23).

Conclusions:

This study showed that majority of cases do not have protective serum antibody against B. pertussis. Working in hospitals does not affect seroprevalence and carrier state of B. pertussis. Immunization schedules that include no booster doses are at increased risk of pertussis. Due to the importance of the transmission in health care settings, vaccination of HCWs is a priority.

Acellular pertussis vaccines in Japan: past, present and future

An antivaccine movement developed in Japan as a consequence of increasing numbers of adverse reactions to whole-cell pertussis vaccines in the mid-1970s. After two infants died within 24 h of the vaccination from 1974 to 1975, the Japanese government temporarily suspended vaccinations. Subsequently, the public and the government witnessed the re-emergence of whooping cough, with 41 deaths in 1979. This series of unfortunate events revealed to the public that the vaccine had, in fact, been beneficial. Furthermore, researchers and the Japanese government proceeded to develop safer pertussis vaccines. Japan now has the most experience worldwide with acellular pertussis vaccines, being the first country to have approved their use. This review describes the major events associated with the Japanese vaccination program. The Japanese experience should be valuable to other countries that are considering the development and use of such vaccines.

Pulmonary and cardiac infections in athletes

Pulmonary and cardiac infections in the athlete can have a wide range of presentations and complications. These infections may present few problems for the training athlete or become life threatening. The team physician must be able to make an accurate diagnosis, give the appropriate treatment, understand the potential complications, and ensure proper follow-up and return-to-play protocols.

Use of antibiotics in the prevention and treatment of pertussis

Antibiotics are commonly used for treating confirmed cases of pertussis and also for disease prevention in outbreak situations, and there is little evidence of antibiotic resistance of Bordetella pertussis. The most commonly used antibiotic is erythromycin, but the associated side effects limit compliance and therefore efficacy. Other antibiotics, such as clarithromycin and azithromycin, have been shown to be at least as effective as erythromycin in preventing and treating pertussis, and they also have fewer side effects, which improves compliance. This article outlines the use of different antibiotics in pertussis management and their effect on preventing disease transmission and reducing disease severity and duration.

[Chronic cough in childhood]

Introduction

La toux chronique de l’enfant bien que moins fréquente que les toux répétées liées aux infections virales reste un problème diagnostique parfois difficile à résoudre.

États des connaissances

La majorité des auteurs estiment que sa durée doit être supérieure à trois semaines. Peu d’études ont été consacrées au diagnostic étiologique de la toux chronique chez l’enfant mais celles-ci retrouvent les mêmes causes principales que chez l’adulte : l’asthme, les pathologies ORL (dont la sinusite), le reflux gastro-œsophagien. Chaque tranche d’âge connaît des étiologies plus spécifiques ; notamment malformatives entre 0 et 1 an, et toux psychogène chez l’adolescent.

Perspectives

Des techniques « nouvelles » comme l’étude de l’expectoration induite permettent d’affiner le diagnostic d’une toux chronique de l’enfant en tout cas après 7 ans. La découverte d’une bronchite à éosinophiles quelle soit associée ou pas à une hyperréactivité bronchique a des conséquences thérapeutiques indiscutables compte tenu de sa corticosensibilité.

Conclusions

L’exploration d’une toux chronique de l’enfant doit reposer sur un raisonnement anatomique et sur des arguments de fréquence. Le contrôle et la disparition de la toux ne seront possibles qu’avec un diagnostic précis et un traitement adapté.

Clinical presentation of pertussis in unvaccinated and vaccinated children in the first six years of life

OBJECTIVES

Identifying the determinants of the clinical presentation of pertussis is important for the purposes of diagnosis, therapy, and control and for predicting the disease's clinical course and choosing an appropriate case definition for surveillance. Potential determinants include vaccination status, antibiotic treatment, age at diagnosis, and sex, although the available data are inconsistent. The objective of this study was to compare the clinical course of pertussis in unvaccinated and vaccinated children in a well-defined and strictly studied population and to identify determinants of the disease's clinical presentation.

METHODS

The clinical presentation of pertussis was studied in children who participated in a randomized, controlled clinical trial of efficacy of acellular pertussis vaccine. The children belonged to the same birth cohort and were followed from infancy to 6 years of age in 3 distinct periods (stages 1, 2, and 3). Children had received 1 of 2 three-component acellular pertussis vaccines produced by 2 manufacturers (diphtheria-tetanus-acellular pertussis from, Chiron Biocine [DTaP CB]; DTaP from SmithKline Beecham [DTaP SB]) or a diphtheria-tetanus vaccine only (DT; Chiron Biocine). Pertussis was confirmed through culture or serology. For each pertussis episode, information was collected on age at onset, sex, type of vaccine received, antibiotic treatment, culture results, duration of cough, spasmodic cough, and other symptoms. The simultaneous effect of potential determinants of clinical presentation of pertussis on the duration of cough and spasmodic cough was studied through analysis of variance models.

RESULTS

The analysis was conducted on 788 laboratory-confirmed cases of pertussis. The median duration of cough in DT recipients varied from 52 to 61 days across the 3 stages, whereas the median duration of cough in DTaP recipients varied from 29 to 39 days. The median duration of spasmodic cough varied from 20 to 45 days in DT recipients and from 14 to 29 days in DTaP recipients. The results of the analysis of variance models showed that vaccination against pertussis reduced the length of cough from 3 to 10 days and the length of spasmodic cough from 4 to 8 days. Culture-positive patients had a cough 11 to 22 days longer and a spasmodic cough 12 to 22 days longer than culture-negative patients. Children who received an antibiotic had a duration of cough 6 to 11 days longer and spasmodic cough 4 to 13 days longer than untreated patients. Girls had a duration of spasmodic cough 7 days longer than boys only after 3 years of age. Age was directly related to duration of cough, whereas it was inversely related to duration of spasmodic cough after 3 years of age.

CONCLUSIONS

Duration of cough can be greatly influenced by vaccination status. A positive culture for Bordetella pertussis is more frequently found in patients with long duration of cough, and antibiotic therapy may be a marker of severe disease. Gender may affect the clinical presentation of pertussis only after infancy. Pertussis in older children may be characterized by short duration of spasmodic cough. These results should be taken into account in the clinical evaluation of patients with suspected pertussis. Clinical case definitions for the purpose of surveillance based on the presence of 2 weeks of spasmodic cough may not be appropriate where pertussis vaccination uptake is high.