Pertussis Culture Research Articles

Association between pertactin-producing Bordetella pertussis and fulminant pertussis in infants: a multicentre study in France, 2008–2019

ObjectivesVirulence factors of the causative agent, Bordetella pertussis, may be involved in fulminant pertussis, the most severe form of whooping cough (pertussis) in infants. We aimed to assess the association between fulminant pertussis and the status of pertactin (PRN) production of B. pertussis clinical isolates. MethodsSymptomatic infants aged <6 months with a positive B. pertussis culture from 2008–2019 were included. B. pertussis isolates and clinical data were collected from French hospital laboratories through the national pertussis surveillance network. Fulminant pertussis was defined as a case with a leukocyte count >40 × 109/L and at least one of the following criteria: respiratory failure, pulmonary hypertension, shock, or multiple organ failure. PRN production was assessed by western blotting. Baseline characteristics of infants and microbiological findings were compared between patients with and without fulminant pertussis. To identify patient and microbiological features associated with fulminant pertussis, a multivariable modified Poisson regression model was developed with confounders selected using a directed acyclic graph. ResultsWe included 361 infants with pertussis (median age 63 days [interquartile range, 39–86]), of whom 32 (9%) progressed to fulminant pertussis. None of the mothers was vaccinated during pregnancy. Of the 361 implicated B. pertussis isolates, 294 (81%) produced PRN. Patients with fulminant pertussis were more often neonates (adjusted relative risk [aRR]: 3.62, 95% confidence interval [CI]: 1.76–7.44), infants with a history of prematurity (aRR: 7.08, 95% CI: 3.06–16.36), unvaccinated infants (aRR: 4.42, 95% CI: 1.02–19.24), and infants infected by PRN-producing isolates (aRR: 3.76, 95% CI: 1.02–13.83). DiscussionPRN-producing B. pertussis was independently associated with an increased risk of fulminant pertussis. In a context where PRN-containing acellular pertussis vaccines favour the emergence of PRN-deficient isolates, our study suggests a positive role for such vaccines in driving the evolution of B. pertussis populations towards reduced virulence.

Deep longitudinal multi-omics analysis of Bordetella pertussis cultivated in bioreactors highlights medium starvations and transitory metabolisms, associated to vaccine antigen biosynthesis variations and global virulence regulation.

Bordetella pertussis is the bacterial causative agent of whooping cough, a serious respiratory illness. An extensive knowledge on its virulence regulation and metabolism is a key factor to ensure pertussis vaccine manufacturing process robustness. The aim of this study was to refine our comprehension of B. pertussis physiology during in vitro cultures in bioreactors. A longitudinal multi-omics analysis was carried out over 26 h small-scale cultures of B. pertussis. Cultures were performed in batch mode and under culture conditions intending to mimic industrial processes. Putative cysteine and proline starvations were, respectively, observed at the beginning of the exponential phase (from 4 to 8 h) and during the exponential phase (18 h 45 min). As revealed by multi-omics analyses, the proline starvation induced major molecular changes, including a transient metabolism with internal stock consumption. In the meantime, growth and specific total PT, PRN, and Fim2 antigen productions were negatively affected. Interestingly, the master virulence-regulating two-component system of B. pertussis (BvgASR) was not evidenced as the sole virulence regulator in this in vitro growth condition. Indeed, novel intermediate regulators were identified as putatively involved in the expression of some virulence-activated genes (vags). Such longitudinal multi-omics analysis applied to B. pertussis culture process emerges as a powerful tool for characterization and incremental optimization of vaccine antigen production.

Retrospective analysis of bacterial culture-confirmed pertussis cases in Beijing Children’s hospital from 2014 to 2019 reveals prevention and control of the grim situation in mainland China

ABSTRACT Background Our study aims to explore the epidemiological features of children with bacterial culture-confirmed pertussis visiting Beijing Children’s Hospital, China. Methods From 2014 through 2019, patients with suspected pertussis coming from mainland China provided nasopharyngeal swabs and bacterial culture that was subsequently cultivated. Results During the study period, 6956 children with suspected pertussis from 30 different administrative provinces of mainland China were investigated, of which 1494 cases (21.5%) had positive B. pertussis culture. The number of pertussis cases increased year-on-year, from 122 in 2014 to 279 in 2019. Of the confirmed cases, 38.2% and 26.8% were identified in the summer and autumn, respectively. The age distribution of children with pertussis showed that 77.2% were <12 months old, including 56.0% <6 months old. Only thirteen B. parapertussis isolates and one B. bronchiseptica isolates were collected in the present samples. Conclusions The present culture-confirmed cases reveal the severe epidemic situation of pertussis spreading over the whole country and mainly affecting the infants. It is necessary to set up hospital-based surveillance with reliable laboratory methods to promote clinical awareness and to monitor the disease.

Abundance of the nasopharyngeal microbiome effects pertussis diagnosis and explains the sensitivity difference between bacterial culture and real-time PCR.

Quantitative real time PCR (qPCR)is used for pertussis diagnosis. The positive rate of qPCR is generally much higher than that of bacterial culture, which may cause confusion. The current study utilized the 16S ribosomal RNA (16S rRNA) sequencing to assess the correlation between conventional culture and qPCR and to explore the value of 16S rRNA in diagnosing pertussis. Nasopharyngeal swabs, collected from 102 children meeting clinical diagnostic criteria for pertussis, were subjected to Bordetella pertussis culture and qPCR. Bioinformatic microbiota analysis was based on 16S rRNA V3-V4 gene sequencing. Among 102 samples, 14 (13.7%) were culture-positive for Bordetella pertussis, while 61 (59.8%) were qPCR positive. Genus Bordetella was identified in 68 (66.7%) samples via 16S rRNA sequencing. When the relative abundance of Bordetella genus exceeded 0.70%, both qPCR and culture results were positive. Samples with a relative abundance of less than 0.20% exhibited positive qPCR and negative culture results. Samples with a low Bordetella abundance are the key factors underlying poor correlation between culture and qPCRresults in laboratory tests.

Bordetella pertussis Infection in Infants and Young Children in Shanghai, China, 2016-2017: Clinical Features, Genotype Variations of Antigenic Genes and Macrolides Resistance.

The global resurgence of pertussis in countries with high vaccination coverage has been a concern of public health. Nasopharyngeal swabs were collected for Bordetella pertussis culture from children with suspected pertussis. Clinical and vaccination information were reviewed through electronic medical chart and immunization record. Antibiotics susceptibility was evaluated using E-test for erythromycin, azithromycin, clarithromycin and sulfamethoxazole/trimethoprim. The MLST genotypes and 7 antigenic genes (ptxP, ptxA, ptxC, Prn, fim3, fim2 and tcfA) of Bordetella pertussis were identified by polymerase chain reaction amplification and sequencing. During January 2016 to September 2017, a total of 141 children 1-48 months of age were culture-confirmed with pertussis, of whom 98 (69.5%) were younger than 6 months, 25 (17.7%) had completed at least 3 doses of DTaP and 75 (53.2%) had a clear exposure to household members with persistent cough. Fully vaccinated cases manifested milder disease than unvaccinated and not-fully vaccinated cases. All strains were MLST2. High-virulent strains characteristic of ptxP3/prn2/ptxC2 constituted 41.1% (58/141) and were all susceptible to macrolides while low-virulent strains characteristic of ptxP1/prn1/ptxC1 constituted 58.9% (83/141) and 97.6% (81/83), respectively, were highly resistant to macrolides. Pertussis is resurging among infants and young children in Shanghai, and household transmission is the main exposure pathway. The high-virulent strains harboring ptxP3/prn2/ptxC2 and the macrolide-resistant Bordetella pertussis strains are quite prevalent. These issues impose a public health concern in Shanghai. Our findings are important to modify the DTaP vaccination strategy and the management guideline of pertussis in China.

Comparing the Yield of Nasopharyngeal Swabs, Nasal Aspirates, and Induced Sputum for Detection of Bordetella pertussis in Hospitalized Infants.

Background. Advances in molecular laboratory techniques are changing the landscape of Bordetella pertussis illness diagnosis. Polymerase chain reaction (PCR) assays have greatly improved the sensitivity detection and the turnaround time to diagnosis compared to culture. Moreover, different respiratory specimens, such as flocked nasopharyngeal swabs (NPSs), nasopharyngeal aspirates (NPAs), and induced sputum, have been used for B. pertussis detection, although there is limited head-to-head comparison to evaluating the PCR yield from the 3 sampling methods.Methods. Hospitalized infants <6 months of age who fulfilled a broad syndromic criteria of respiratory illness were tested for B. pertussis infection by PCR on paired NPSs and NPAs; or paired NPSs and induced sputum. An exploratory analysis of B. pertussis culture was performed on induced sputum specimens and in a subset of NPSs.Results. From November 2014 to May 2015, 484 infants with paired NPSs and NPAs were tested; 15 (3.1%) PCR-confirmed pertussis cases were identified, 13 of which were PCR positive on both samples, while 1 each were positive only on NPS or NPA. From March to October 2015, 320 infants had NPSs and induced sputum collected, and 11 (3.4%) pertussis cases were identified by PCR, including 8 (72.7%) positive on both samples, 1 (9.1%) only positive on NPS, and 2 (18.2%) only positive on induced sputum. The 3 types of specimens had similar negative predictive value >99% and sensitivity >83%. Compared to PCR, culture sensitivity was 60% in induced sputum and 40% in NPSs.Conclusions. Flocked nasopharyngeal swabs, nasopharyngeal aspirates, and induced sputum performed similarly for the detection of B. pertussis infection in young infants by PCR.

Elevated Pertussis Reporting in Response to 2011-2012 Outbreak, New York City, New York, USA.

Elevated Pertussis Reporting in Response to 2011-2012 Outbreak, New York City, New York, USA.

Bordetella pertussis diagnosis in children under five years of age in the Regional Hospital of Cajamarca, Northern Peru.

Bordetella pertussis is an important human pathogen that causes whooping cough (pertussis), an endemic illness responsible of significant morbidity and mortality, especially in infants and children. Worldwide, there are an estimated of 16 million cases of pertussis, resulting in about 195,000 child deaths per year. In Peru, pertussis is a major health problem that has been on the increase despite immunization efforts. The objective of this study was to determine the prevalence of B. pertussis among children under five years of age suspected to have whopping cough in Cajamarca, Peru. Children diagnosed with whooping cough admitted to the Hospital Regional de Cajamarca from August 2010 to July 2013 were included. Nasopharyngeal samples were obtained for B. pertussis culture and polymerase chain reaction (PCR) detection. In 133 children, the pertussis toxin and IS481 gene were detected in 38.35% (51/133) of the cases by PCR, while only 9.02% (12/133) of the Bordetella cultures were positive. The most frequent symptoms in patients with positive B. pertussis were paroxysm of coughing 68.63% (35/51), cyanosis 56.86% (29/51), respiratory distress 43.14% (22/51), and fever 39.22% (20/51). Pneumonia and acute bronchial obstructive syndrome were present in 17.65% (9/51) and 13.72% (7/51) of the cases, respectively. B. pertussis is responsible for an important proportion of whooping cough in hospitalized children in Cajamarca. Epidemiologic surveillance programs for B. pertussis are essential in Peru, especially in children who could most benefit from the vaccine.

A versatile, non genetically modified organism (GMO)-based strategy for controlling low-producer mutants in Bordetella pertussis cultures using antigenic modulation.

The uncontrolled presence of non-producer mutants negatively affects bioprocesses. In Bordetella pertussis cultures, avirulent mutants emerge spontaneously and accumulate. We characterized the dynamics of accumulation using high-throughput growth assays and competition experiments between virulent and avirulent (bvg(-) ) isolates. A fitness advantage of bvg(-) cells was identified as the main driver for bvg(-) accumulation under conditions of high virulence factor production. Conversely, under conditions that reduce their expression (antigenic modulation), bvg(-) takeover could be avoided. A control strategy was derived, which consists in applying modulating conditions whenever virulence factor production is not required. It has a wide range of applications, from routine laboratory operations to vaccine manufacturing, where pertussis toxin yields were increased 1.4-fold by performing early pre-culture steps in modulating conditions. Because it only requires subtle modifications of the culture medium and does not involve genetic modifications, this strategy is applicable to any B. pertussis isolate, and should facilitate regulatory acceptance of process changes for vaccine production. Strategies based on the same concept, could be derived for other industrially relevant micro-organisms. This study illustrates how a sound scientific understanding of physiological principles can be turned into a practical application for the bioprocess industry, in alignment with Quality by Design principles.

A retrospective study of acute pertussis in Hasan Sadikin Hospital–Indonesia

ObjectiveTo describe the representation of pertussis diagnosis in children. MethodsA retrospective observational study was performed on pediatric pertussis and pertussis-like syndrome registry for children <14 years of age documented from October 2008 to December 2014 in Hasan Sadikin Hospital, Indonesia. Demographic data, signs and symptoms at presentation, case definition (probable, confirmed), possible pertussis contact, pertussis vaccination status, results of Bordetella pertussis (B. pertussis) culture, complications, and outcome were recorded. ResultsSixty-one probable and two confirmed pertussis were documented. Male and female ratio was 1:1, mostly presented with shortness of breath, 24 (38%) subjects had posttussive vomiting, 10 (16%) had whooping-cough. Ten patients (16%) were reported to have adult possible pertussis contact. Only 2 infants had previous pertussis vaccination. All subjects presented in the second week of illness were all diagnosed as bronchopneumonia but two. The mean age was 6 months, ranging from 0–50 months. One subject required mechanical ventilation. B. pertussis culture was performed only in 35 (56%) subjects but positive only in two. There were no fatal cases, 55 (87%) including the subject who need mechanical ventilation had good outcome. ConclusionsMostly patients were admitted on paroxysmal phase when no more active B. pertussis could be found from nasopharyngeal secret. A rigorous history taking particularly excessive cough, posttussive vomitting, and pertussis vaccination status need to be taken into account.

In vivo phosphorylation dynamics of the Bordetella pertussis virulence‐controlling response regulator BvgA

We have used protein electrophoresis through polyacrylamide gels derivatized with the proprietary ligand Phos-tag™ to separate the response regulator BvgA from its phosphorylated counterpart BvgA∼P. This approach has allowed us to readily ascertain the degree of phosphorylation of BvgA in in vitro reactions, or in crude lysates of Bordetella pertussis grown under varying laboratory conditions. We have used this technique to examine the kinetics of BvgA phosphorylation after shift of B. pertussis cultures from non-permissive to permissive conditions, or of its dephosphorylation following a shift from permissive to non-permissive conditions. Our results provide the first direct evidence that levels of BvgA∼P in vivo correspond temporally to the expression of early and late BvgA-regulated virulence genes. We have also examined a number of other aspects of BvgA function predicted from previous studies and by analogy with other two-component response regulators. These include the site of BvgA phosphorylation, the exclusive role of the cognate BvgS sensor kinase in its phosphorylation in Bordetella pertussis, and the effect of the T194M mutation on phosphorylation. We also detected the phosphorylation of a small but consistent fraction of BvgA purified after expression in Escherichia coli.

Pertussis resurgence in Toronto, Canada: a population-based study including test-incidence feedback modeling.

BackgroundPertussis continues to challenge medical professionals; recently described increases in incidence may be due to age-cohort effects, vaccine effectiveness, or changes in testing patterns. Toronto, Canada has recently experienced increases in pertussis incidence, and provides an ideal jurisdiction for evaluating pertussis epidemiology due to centralized testing. We evaluated pertussis trends in Toronto using all available specimen data, which allowed us to control for changing testing patterns and practices.MethodsData included all pertussis culture and PCR test records for Greater Toronto from 1993 to 2007. We estimated incidence trends using Poisson regression models; complex relationships between disease incidence and test submission were explored with vector autoregressive models.ResultsFrom 1993 to 2007, 26988 specimens were submitted for testing; 2545 (9.4%) were positive. Pertussis incidence was 2 per 100,000 from 1993 to 2004 and increased to 10 per 100,000 from 2005-2007, with a concomitant 6-fold surge in test specimen submissions after the introduction of a new, more sensitive PCR assay. The relative change in incidence was less marked after adjustment for testing volumes. Bidirectional feedbacks between test positivity and test submissions were identified.ConclusionsToronto's recent surge in pertussis reflects a true increase in local disease activity; the apparent size of the outbreak has likely been magnified by increasing use of pertussis testing by clinicians, and by improved test sensitivity since 2005. These findings may be applicable to changes in pertussis epidemiology that have been noted elsewhere in North America.

Real-time PCR-based detection of Bordetella pertussis and Bordetella parapertussis in an Irish paediatric population

Novel real-time PCR assays targeting the Bordetella pertussis insertion sequence IS481, the toxin promoter region and Bordetella parapertussis insertion sequence IS1001 were designed. PCR assays were capable of detecting ≤10 copies of target DNA per reaction, with an amplification efficiency of ≥90 %. From September 2003 to December 2009, per-nasal swabs and nasopharyngeal aspirates submitted for B. pertussis culture from patients ≤1 month to >15 years of age were examined by real-time PCR. Among 1324 patients, 76 (5.7 %) were B. pertussis culture positive and 145 (10.95 %) were B. pertussis PCR positive. Of the B. pertussis PCR-positive patients, 117 (81 %) were aged 6 months or less. A total of 1548 samples were examined, of which 87 (5.6 %) were culture positive for B. pertussis and 169 (10.92 %) were B. pertussis PCR positive. All culture-positive samples were PCR positive. Seven specimens (0.5 %) were B. parapertussis culture positive and 10 (0.8 %) were B. parapertussis PCR positive, with all culture-positive samples yielding PCR-positive results. A review of patient laboratory records showed that of the 1324 patients tested for pertussis 555 (42 %) had samples referred for respiratory syncytial virus (RSV) testing and 165 (30 %) were positive, as compared to 19.4 % of the total 5719 patients tested for RSV in this period. Analysis of the age distribution of RSV-positive patients identified that 129 (78 %) were aged 6 months or less, similar to the incidence observed for pertussis in that patient age group. In conclusion, the introduction of the real-time PCR assays for the routine detection of B. pertussis resulted in a 91 % increase in the detection of the organism as compared to microbiological culture. The incidence of infection with B. parapertussis is low while the incidence of RSV infection in infants suspected of having pertussis is high, with a similar age distribution to B. pertussis infection.

New combination of methods for isolation and purification of pertussis toxin from the Bordetella pertussis culture

In this paper a method for isolation and purification of the pertussis toxin from the cell culture of Bordetella pertussis was presented. Pertussis toxin production was enhanced with the optimization of the microbiological media and cultivation time. Relatively high degree of purification of 80,39% and yield of 56% was resulted by the unique combination of the protein isolation and purification methods. Using immunoelectrophoresis and high performance liquid chromatography, in comparison with pertussis toxin WHO standard, it was verified that the protein isolated is indeed pertussis toxin. The conclusion of this paper is that this unique combination of the different techniques along with the specific modifications implemented would give good results in pertussis toxin isolation and purification on laboratory level, while scaling up of this methodology could be the objective of future research. It can also be concluded that, no matter what literature data say and what opinions other authors have, all methods and working conditions should be examined and optimized for the reason of the specificity of the autochthonous species as well as the dynamic changes in this field.

Use of population health data to refine diagnostic decision-making for pertussis

To improve identification of pertussis cases by developing a decision model that incorporates recent, local, population-level disease incidence. Retrospective cohort analysis of 443 infants tested for pertussis (2003-7). Three models (based on clinical data only, local disease incidence only, and a combination of clinical data and local disease incidence) to predict pertussis positivity were created with demographic, historical, physical exam, and state-wide pertussis data. Models were compared using sensitivity, specificity, area under the receiver-operating characteristics (ROC) curve (AUC), and related metrics. The model using only clinical data included cyanosis, cough for 1 week, and absence of fever, and was 89% sensitive (95% CI 79 to 99), 27% specific (95% CI 22 to 32) with an area under the ROC curve of 0.80. The model using only local incidence data performed best when the proportion positive of pertussis cultures in the region exceeded 10% in the 8-14 days prior to the infant's associated visit, achieving 13% sensitivity, 53% specificity, and AUC 0.65. The combined model, built with patient-derived variables and local incidence data, included cyanosis, cough for 1 week, and the variable indicating that the proportion positive of pertussis cultures in the region exceeded 10% 8-14 days prior to the infant's associated visit. This model was 100% sensitive (p<0.04, 95% CI 92 to 100), 38% specific (p<0.001, 95% CI 33 to 43), with AUC 0.82. Incorporating recent, local population-level disease incidence improved the ability of a decision model to correctly identify infants with pertussis. Our findings support fostering bidirectional exchange between public health and clinical practice, and validate a method for integrating large-scale public health datasets with rich clinical data to improve decision-making and public health.

Analysis of Secreted Protein Profile and Enzymatic Activities from Corynebacterium diphtheriae and Bordetella pertussis on Production Batch Media using Peptide Quenched Fluorescent Substrates

Proteases were identified and characterized from the culture supernatant of the C. diphtheriae and B. pertussis bacteria. The proteases were secreted in the media and detected at the end of the exponential growth phase. Activity was detected in some fluorescent substrates, based on selected protein sequences such as insuline β‐chain, bradykinin, and synaptobrevin. The proteases were purified by means of gel filtration chromatography. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) analysis of the purified proteins indicated, for the main secreted proteins, an estimated molecular mass of 30 kDa in C. diphtheriae and 69 kDa in B. pertussis culture media. The proteases were stable and presented enzymatic activity at 37°C. These proteases were not related to the main toxic compounds described in these two bacteria, but could represent good markers for the fermentation process when the enzyme activity was measured with the fluorescent substrates.

Evaluation of Polymerase Chain Reaction and Culture for Diagnosis of Pertussis in the Control of a County-Wide Outbreak Focused among Adolescents and Adults

During a large pertussis outbreak, culture and polymerase chain reaction (PCR) were used to identify 149 case patients; of these case patients, 79 had positive PCR and culture results, 59 had positive PCR results and negative culture results, 11 had negative PCR results and positive culture results (10 PCR-negative, culture-positive specimens were collected < or = 14 days after illness onset). PCR and culture of samples obtained < or = 2 weeks after illness onset and PCR of samples obtained > 2 weeks after illness onset proved to be most diagnostically useful.

Laboratory diagnosis of pertussis infections: the role of PCR and serology

This study reports on practical laboratory aspects of pertussis diagnosis. PCR assays were applied to respiratory specimens obtained during a large study of infants (less than 5 months old) admitted to paediatric intensive care units (n = 122), children (less than 15 years old) admitted to paediatric wards (n = 16) and their household contacts (n = 320). Estimation of antibodies to pertussis toxin and culture for Bordetella pertussis were attempted on specimens from the same patients, where available, and the overall utility of the diagnostic PCR assays was assessed by comparison to these results. A PCR assay for the human mitochondrial cytochrome oxidase (HMCO) gene was used for quality control of the extracted samples and an internal process control (IPC) was included in each sample to test for PCR inhibition. Four of 458 samples were considered unsuitable (three HMCO negative, one IPC negative) and excluded from further analyses. Positive PCR results were considered valid if they were either (i) positive for both of two B. pertussis gene targets (pertussis toxin S1 promoter and the insertion element IS481), i.e. consensus PCR positive, or (ii) repeatably positive in only one assay. Using these criteria, 52 of 454 (11.5 %) samples were considered as PCR positive for B. pertussis. Six of 356 samples were culture-positive for B. pertussis, 1/88 infants, 3/14 children and 2/254 contacts, giving an overall isolation rate of 1.7 %. Using these data, PCR gave an almost fivefold increase in diagnostic yield compared with culture (McNemar's test; P < 0.0001). Sera from 9/111 infants, 5/10 children and 14/210 contacts were positive. Serology and PCR results showed a high level of agreement (113/121) for infants and children. PCR demonstrated a significant improvement in diagnostic yield over culture. Serological testing also resulted in a significant increase in diagnostic yield compared to culture alone. PCR is a useful technique, but validity of results must be assured by careful control. Rapid diagnosis of B. pertussis infection particularly in infants by PCR, together with serological assays, can enhance surveillance systems for pertussis in all age groups.

Pertussis, the Pediatrician, and the Outbreak

BACKGROUND: A neonate presented with worsening gastrointestinal and respiratory distress. Pertussis isolation precautions were not initiated until 3 days after presentation. Although the initial Pertussis DFA was negative, the Pertussis culture was positive. METHODS: Surveillance for close contacts was begun. Exposed, asymptomatic healthcare workers (HCWs) were given azithromycin prophylaxis. The attending pediatrician developed a cough 9 days after the exposure and tested positive for Pertussis by PCR. Five other exposed, symptomatic HCWs met the confirmed case classification, despite negative laboratory findings. Surveillance and prophylaxis for cases exposed to the pediatrician and the five HCWs were begun. RESULTS: Two-hundred-thirty-one exposed patients and their family members were seen in the hospital setting and given prophylaxis; 51 of these individuals with a cough were tested for Pertussis by PCR and culture. The one positive contact was linked to an unrelated Pertussis case. The five exposed HCWs also spent clinical time in various outpatient settings. Ninety days after the index case presented, the pediatrician remains the only laboratory-confirmed secondary case. CONCLUSIONS: Pertussis should be part of the differential diagnosis in all patients < 6 months of age who present with an upper respiratory illness or distress. Droplet precautions should be initiated promptly in these patients. The current case definition when applied to individuals with negative laboratory findings can lead to expensive diagnostic testing, inappropriate antibiotic use, unneeded school/work furlough, and over-taxing of healthcare resources. Further investigation into the safety of immunizing adults with a Pertussis vaccine is needed.

School-Associated Pertussis Outbreak—Yavapai County, Arizona, September 2002–February 2003

On September 21, 2002, a pertussis case (confirmed by isolation of Bordetella pertussis) was reported to the Yavapai County Health Department (YCHD). The patient was a child aged 13 years in the 8th grade at a middle school in Yavapai County; the child had attended school during the illness. A case consistent with the clinical definition of pertussis had been reported in another student in the same classroom 2 weeks earlier. On September 22, a second culture-confirmed case was reported from the same classroom. Subsequent investigation identified five additional persons (two students in the same classroom, two 8th-grade teachers, and one parent of an ill student) with prolonged cough illnesses. In comparison, during the previous 10 years, an average of four pertussis cases were reported annually from this county. On September 26, YCHD, in conjunction with the Arizona Department of Health Services (ADHS) and school officials, notified the community of the pertussis outbreak in the middle school and initiated control measures. This report summarizes the epidemiology of the outbreak and the control measures used to contain it. Health-care providers should consider pertussis in persons of any age with acute cough illnesses and consider obtaining nasopharyngeal (NP) specimens for B. pertussis culture.