Testing implications of varying targets for Bordetella pertussis: comparison of the FilmArray Respiratory Panel and the Focus B. pertussis PCR assay

Diagnostic Stewardship for Multiplex Respiratory Testing: What We Know and What Needs to Be Done

Syndromic respiratory panels are now widely available in clinical microbiology laboratories and health care institutions. These panels can rapidly diagnose infections and detect antimicrobial resistance genes allowing for more rapid therapeutic optimization compared to standard microbiology approaches. However, given reimbursement concerns and limitations of multiplex molecular testing and results interpretation, maximum clinical utility and positive clinical outcomes depend on active diagnostic stewardship. Here, the authors review clinical outcomes of both upper and lower respiratory panels and present diagnostic stewardship strategies for optimal use of respiratory panels.

The Clinical Performance of the BioCode Respiratory Pathogen Panel for the Detection of Viruses and Bacteria from Nasopharyngeal Swabs

Early detection of microbial pathogens causing respiratory tract infection plays a crucial role in clinical management. The BioCode Respiratory Pathogen Panel (BioCode RPP) utilizes reverse transcriptase PCR (RT-PCR) in combination with barcoded magnetic beads to amplify, detect, and identify respiratory pathogens. This panel qualitatively detects and identifies 14 viruses, including influenza virus A with H1 pdm09, H1, and H3 subtyping; influenza B; respiratory syncytial virus (RSV); human metapneumovirus; parainfluenza virus 1; parainfluenza virus 2; parainfluenza virus 3; parainfluenza virus 4; coronavirus (229E, NL63, OC43, and HKU1); adenovirus; and human rhinovirus/enterovirus, and 3 bacteria, including Chlamydia pneumoniae, Mycoplasma pneumoniae, and Bordetella pertussis. Reproducibility, which was assessed with contrived specimens containing 12 targets at 3 clinical sites, with 2 operators at each site for 5 days, was 99.4% for Flu A H3 and Flu B, 98.9% for RSV, and 100% for the remaining 9 targets assayed. A multicenter clinical trial evaluated the performance of the BioCode RPP with 2,647 nasopharyngeal swab specimens from 5 geographically distinct sites and revealed comparable performance between the BioCode RPP and FilmArray Respiratory Panel (FA-RP). Specifically, the positive percent agreements (PPAs) for various pathogens ranged between 80.8% and 100% compared with the FA-RP (1.7 and 2.0). Negative percent agreement ranged from 98.4% to 100% for BioCode RPP. The BioCode RPP also offers scalable automated testing capability of up to 96 specimens in a single run with total sample-to-result time under 5 h. The invalid rate of the BioCode RPP on initial testing was 1.0% (26/2,649). IMPORTANCE Early detection of microbial pathogens causing respiratory tract infection plays a crucial role in clinical management. The BioCode Respiratory Pathogen Panel (BioCode RPP) is a high-throughput test that utilizes RT-PCR in combination with barcoded magnetic beads to amplify, detect, and identify 17 respiratory pathogens, including 14 viruses and 3 bacteria. This study summarizes data generated from a multicenter clinical trial evaluating the performance of the BioCode RPP on 2,647 nasopharyngeal swab specimens from five geographically distinct sites.

Evaluation of BioFire Respiratory Panel 2 plus for Detection of Bordetella pertussis in Nasopharyngeal Swab Specimens from Children with Clinically Suspected Pertussis

The objective of this study was to compare the performances of BioFire Respiratory Panel 2 (RP2) plus, quantitative real-time PCR (qPCR), and culture for the detection of Bordetella pertussis in nasopharyngeal swab (NPS) specimens. Consecutive NPS specimens were collected from patients with clinically suspected pertussis from 1 March 1 to 31 July 2018 in Shenzhen Children's Hospital. All the specimens were tested in parallel by RP2 plus, qPCR, and culture methods. A total of 464 children were enrolled in this study. The positive pertussis rates of culture, RP2 plus, and qPCR were 23.1%, 39.0%, and 38.4%, respectively. Compared to the combined reference standard, the sensitivity, specificity, positive predictive value, and negative predictive values were, respectively, 56.6% (95% confidence interval [CI], 49.2 to 63.7%), 100% (98.3 to 100%), 100% (95.7 to 100%), and 77.0% (72.2 to 81.2%) for culture, 89.9% (84.5 to 93.7%), 96.0% (92.8 to 97.9%), 93.9% (89.1 to 96.8%), and 93.3% (89.5 to 95.8%) for RP2 plus, and 86.8% (80.9 to 91.1%), 94.9% (91.4 to 97.1%), 92.1% (86.9 to 95.5%), and 91.3% (87.2 to 94.2%) for qPCR. The most prevalent codetected pathogen was human rhinovirus/enterovirus (n = 99, 52.4%), followed by parainfluenza virus (n =32, 16.9%) and respiratory syncytial virus (n = 29, 15.3%), in children with B. pertussis present, which was consistent with the top three pathogens previously found in children with B. pertussis absent. Turnaround times for RP2 plus, qPCR, and culture were 2 h, 8 h, and 120 h, respectively. RP2 plus quickly and accurately detected B. pertussis, providing valuable information for an early clinical diagnosis and optimal choice of therapy. IMPORTANCE In recent years, there have been some epidemic or local outbreaks of pertussis in countries with high vaccination rates. One of the crucial factors in controlling pertussis is early diagnosis, which is based on specific laboratory measurements, including culture, serological tests, and PCR assays. Compared to culture and serological tests, PCR is more suitable for clinical application, with a fast detection speed of several hours independent of the disease stage and individual vaccination status. BioFire Respiratory Panel 2 plus, a multiplex PCR assay for simultaneously detecting 22 respiratory pathogens, facilitates the quick detection of Bordetella pertussis and coinfecting respiratory pathogens. It also provides valuable information for an early clinical diagnosis and optimal choice of therapy for children with clinically suspected pertussis.

Evaluation of the Genmark ePlex® and QIAstat-Dx® respiratory pathogen panels in detecting bacterial targets in lower respiratory tract specimens

Background

The ePlex® and QIAstat-Dx® respiratory pathogen panels detect multiple respiratory pathogens, mainly viruses but also Legionella pneumophila, Mycoplasma pneumoniae and Bordetella pertussis. The assays have been marketed for use in nasopharyngeal swab specimens. For diagnosing bacterial pneumonia, lower respiratory tract (LRT) specimens are indicated. Aim of this study was to evaluate the performance of these syndromic panels for these three bacterial targets in samples from the LRT. Fifty-six specimens were collected from our repositories, five negative samples and fifty-one samples which had been previously tested positive with the routine diagnostic real-time PCR assays for Legionella spp. (N = 20), Bordetella spp. (N = 16) or M. pneumoniae (N = 15).

Results

The QIAstat-Dx Respiratory Panel V2 (RP) assay detected all of the L. pneumophila and B. pertussis positive samples but only 11/15 (73.3 %) of the M. pneumoniae targets. The ePlex Respiratory Pathogen Panel (RPP) assay detected 10/14 (71.4 %) of the L. pneumophila targets, 8/12 (66.7 %) of the B. pertussis positive samples and 13/15 (86.7 %) of the M. pneumoniae targets.

Conclusions

No false-positive results were reported for all three bacterial pathogens by both assays. The clinical performance of both assays depended highly on the bacterial load in the sample and the type of specimen under investigation.

The Need for Dedicated Microbiology Leadership in the Clinical Microbiology Laboratory

Clinical microbiology laboratories play a crucial role in patient care using traditional and innovative diagnostics. Challenges faced by laboratories include emerging pathogens, rapidly evolving technologies, health care-acquired infections, antibiotic-resistant organisms, and diverse patient populations. Despite these challenges, many clinical microbiology laboratories in the United States are not directed by doctoral level microbiology-trained individuals with sufficient time dedicated to laboratory leadership. The manuscript highlights the need for medical microbiology laboratory directors with appropriate training and qualifications.

Can Comprehensive Respiratory Pathogen Panels be Used to Exclude Pertussis Infection?

BACKGROUND

Pertussis is a serious public health concern and accurate diagnosis is imperative. Comprehensive, multiplex respiratory pathogen polymerase chain reaction (PCR) panels (RPPs) have recently become popular, but their utility in excluding pertussis infection has not been fully explored.

OBJECTIVES

To determine RPP testing results for pertussis using frozen banked samples that previously tested positive on dedicated Bordetella pertussis PCR testing, and to describe positive test rates for other respiratory pathogens on these samples via RPP.

METHODS

Our microbiology laboratory retrieved banked nasopharyngeal samples from inpatient, ambulatory, and emergency department sources that were positive for pertussis using B. pertussis PCR testing from March 2015 to October 2017. RPP was performed on thawed, archived samples. Rate of pertussis identification on RPP was determined, and positive tests for other pathogens were tabulated.

RESULTS

A total of 3482 specimens were submitted for pertussis PCR testing during the study period. Of those, 138 (4%) were positive for B. pertussis, and 102 (74%) samples were banked and available for RPP testing. Fifty-seven of 102 (56%) of the banked samples had positive RPP testing for pertussis. Of the 45 samples negative for pertussis on RPP testing, 20 (44%) tested positive for other respiratory pathogens.

CONCLUSION

Negative testing for B. pertussis and positive testing for other respiratory pathogens on RPP was common in samples that previously tested positive on dedicated B. pertussis PCR testing, both of which could lead to missed diagnoses of pertussis infection. Clinicians should consider using dedicated pertussis PCR testing if pertussis infection is suspected.

Physicians' prediction for the assessment of atypical pathogens in respiratory tract infections

BACKGROUND

Patients with acute respiratory tract infections are frequently prescribed antimicrobials despite high rates of virus detection. Physicians may overprescribe antimicrobials owing to the concern of bacterial infections, including those because of atypical pathogens. We investigated the accuracy of clinical predictions concerning atypical pathogen infections.

METHODS

We prospectively enrolled adult patients who presented with a fever and cough in outpatient clinics between December 2016 and August 2018. After taking a history and performing physical examinations, physicians predicted the possibility of respiratory infections because of atypical pathogens. Disease probabilities were categorized into 3 grades (high: ≥50%, intermediate: 20% ≥ and <50%, and low: <20%) and were judged by physicians who were taking care of the patients. Confirmation of atypical pathogens was performed by comprehensive molecular analyses of respiratory samples.

RESULTS

Atypical pathogens were detected in 21 of 210 patients. A close contact history (odds ratio [OR]: 11.4, 95% confidence interval [CI]: 2.4-53.5) and the presence of pneumonia (OR: 12.9, CI: 4.3-39.2) were associated with the detections. Atypical pathogens were detected in 32.3% of high-probability cases (10/31), while atypical pathogens were only detected in 8.8% of intermediate-probability cases (8/91) and 3.4% of low-probability cases (3/88) (P < .001).

CONCLUSIONS

The current study indicates that physicians' predictions were associated with the detection of atypical pathogens; however, overestimation was observed.

Neurologic alterations in an HIV adult patient with pertussis: a case report

Background

Pertussis is a highly contagious disease of public health interest caused by the bacterium Bordetella pertussis. Although its incidence has decreased substantially after the introduction of a vaccination, the burden of the disease remains high. Although the paroxysmal phase is highly disabling, complications are uncommon and more prevalent in children than in adults. The most frequent neurological complication is encephalopathy, but seizures, paresis, paraplegia, ataxias, aphasias, and decerebration postures have also been described. The complication of decerebration postures has not been previously reported in adults.

Case presentation

We present a video case of an adult HIV patient with severe coughing paroxysms, post-tussive emesis and syncope, whose workup confirmed the diagnosis of a B. pertussis respiratory infection. During hospitalization, he had fluctuant encephalopathy and post-tussive decerebration postures following paroxysms. He was treated with antibiotic therapy and finally sent home without residual neurological deficits.

Conclusion

This case illustrates the biological plausibility of neurologic complications of pertussis in adults, which, albeit rare, can cause important morbidities. Future research should explore whether there are differences in the clinical presentation, risk factors and pathophysiology of the disease among adults or interventions aimed at preventing or treating pertussis encephalopathy.

Low Detection Rate of Bordetella pertussis Using the BioFire FilmArray Respiratory Panel 2plus

Syndromic respiratory panels are increasingly used worldwide. Their performance for detection of Bordetella pertussis needs to be evaluated. We found that the FilmArray Respiratory Panel 2plus (RP2+) assay, which uses the pertussis toxin promoter target for B. pertussis, can only detect highly charged samples. Negative RP2+ results should not be interpreted as an absence of B. pertussis in clinical samples.

Multicenter Evaluation of the QIAstat-Dx Respiratory Panel for Detection of Viruses and Bacteria in Nasopharyngeal Swab Specimens

The QIAstat-Dx Respiratory Panel (QIAstat-Dx RP) is a multiplex in vitro diagnostic test for the qualitative detection of 20 pathogens directly from nasopharyngeal swab (NPS) specimens. The assay is performed using a simple sample-to-answer platform with results available in approximately 69 min. The pathogens identified are adenovirus, coronavirus 229E, coronavirus HKU1, coronavirus NL63, coronavirus OC43, human metapneumovirus A and B, influenza A, influenza A H1, influenza A H3, influenza A H1N1/2009, influenza B, parainfluenza virus 1, parainfluenza virus 2, parainfluenza virus 3, parainfluenza virus 4, rhinovirus/enterovirus, respiratory syncytial virus A and B, Bordetella pertussis, Chlamydophila pneumoniae, and Mycoplasma pneumoniae This multicenter evaluation provides data obtained from 1,994 prospectively collected and 310 retrospectively collected (archived) NPS specimens with performance compared to that of the BioFire FilmArray Respiratory Panel, version 1.7. The overall percent agreement between QIAstat-Dx RP and the comparator testing was 99.5%. In the prospective cohort, the QIAstat-Dx RP demonstrated a positive percent agreement of 94.0% or greater for the detection of all but four analytes: coronaviruses 229E, NL63, and OC43 and rhinovirus/enterovirus. The test also demonstrated a negative percent agreement of ≥97.9% for all analytes. The QIAstat-Dx RP is a robust and accurate assay for rapid, comprehensive testing for respiratory pathogens.

Identification of etiologic agents and clinical characteristics for patients suspected of having pertussis in a large Children's Hospital in China

BACKGROUND

In China, pertussis is a major health problem with an increasing incidence despite immunization efforts. Timely and accurate diagnosis is essential for the optimal management of pertussis, especially in severe cases.

METHODS

Nasopharyngeal swabs or sputum specimens were obtained from patients suspected of having pertussis on the day of hospitalization at Shanghai Children's Medical Center from December 01, 2016, to November 30, 2017. The specimens were tested with the FilmArray Respiratory Panel, a multiplex polymerase chain reaction (PCR) assay that detects 16 viruses, Bordetella pertussis (B. pertussis), Mycoplasma pneumoniae (M. pneumoniae), and Chlamydophila pneumoniae (C. pneumoniae).

RESULTS

Among the 140 children studied, 50.0% (70/140) were detected with a single pathogen, 45.0% (63/140) were detected with multiple pathogens, and 5.0% (7/140) had no detected pathogens. Forty-nine (35%, 49/140) patients tested positive for B. pertussis. Respiratory syncytial virus (RSV), parainfluenza virus (Para) and rhinovirus/enterovirus (Rhino/Entero) were the most prevalent pathogens in patients with pertussis-like syndrome. No significant differences between the groups with pertussis and pertussis-like syndrome were observed regarding the clinical symptoms. Severe cases were more frequently observed in unvaccinated, premature and pertussis/RSV co-infection patients.

CONCLUSIONS

Our study highlights the importance of the timely and accurate diagnosis of pertussis based on both clinical symptoms and laboratory methods.

Benefits and risks of standardization, harmonization and conformity to opinion in clinical laboratories

Large laboratory systems that include facilities with a range of capabilities and capacity are being created within consolidated healthcare systems. This paradigm shift is being driven by administrators and payers seeking to achieve resource efficiencies and to conform practice to the requirements of computerization as well as the adoption of electronic medical records. Although standardization and harmonization of practice improves patient care outcomes and operational efficiencies, administratively driven practice conformity (conformity to opinion) also has serious drawbacks and may lead to significant system failure. Juxtaposition of the distinct philosophical approaches of physicians and scientists (i.e. "professionalism") versus administrators and managers (i.e. "managerialism") towards bringing about conformity of the laboratory system inherently creates conflict. Despite an administrative edict to "perform all tests using the same methods" regardless of available "best practice" evidence to do so, medical/scientific input on these decisions is critical to ensure quality and safety of patient care. Innovation within the laboratory system, including the adoption of advanced technologies, practices, and personalized medicine initiatives, will be enabled by balancing the relentless drive by non-medical administration to meet "business" requirements, the medical responsibility to provide the best care possible, and customizing practice to meet individual patient care needs.

Evaluation of the Aries Bordetella Assay for Detection and Identification of Bordetella pertussis in Nasopharyngeal Swab Specimens

The Aries Bordetella assay (Aries BA) (Luminex Corporation) recently received FDA clearance for the detection and differentiation of Bordetella pertussis and Bordetella parapertussis nucleic acids in nasopharyngeal swab (NPS) samples. The objective of this study was to evaluate the performance of the Aries BA in comparison to that of the BioFire FilmArray respiratory panel (RP). The Aries BA was evaluated using retrospective, remnant nasopharyngeal swabs (NPS), previously tested by FilmArray RP. Performance characteristics evaluated included positive percent agreement (PPA) and negative percent agreement (NPA) with the FilmArray RP. Discordant analysis was performed using bidirectional sequencing. A time and motion study was performed to compare the laboratory workflow of the two tests. Three hundred samples were included in the study. There were no samples positive for B. parapertussis The PPA and NPA of the Aries BA were 61.1% (95% confidence interval [CI], 35.8 to 82.7%) and 100% (95% CI, 98.7 to 100%). Discordant results included five Bordetella bronchiseptica results that were incorrectly identified as B. pertussis by the FilmArray RP and one false-negative result for both the Aries BA and the FilmArray RP. The overall agreement between the Aries BA and FilmArray RP for the detection of B. pertussis was considered good at 97.7% with a kappa value of 0.71 (95% CI, 0.51 to 0.9). The Aries BA offers a new diagnostic option for the rapid and targeted approach to the diagnosis of pertussis. Unlike the FilmArray RP, the Aries BA did not cross-react with B. bronchiseptica in our study, although a larger sample set should be tested to confirm this finding.

Multicenter Evaluation of BioFire FilmArray Respiratory Panel 2 for Detection of Viruses and Bacteria in Nasopharyngeal Swab Samples

The FilmArray Respiratory Panel 2 (RP2) is a multiplex in vitro diagnostic test for the simultaneous and rapid (∼45-min) detection of 22 pathogens directly from nasopharyngeal swab (NPS) samples. It contains updated (and in some instances redesigned) assays that improve upon the FilmArray Respiratory Panel (RP; version 1.7), with a faster run time. The organisms identified are adenovirus, coronavirus 229E, coronavirus HKU1, coronavirus NL63, coronavirus OC43, human metapneumovirus, human rhinovirus/enterovirus, influenza virus A, influenza virus A H1, influenza virus A H1-2009, influenza virus A H3, influenza virus B, parainfluenza virus 1, parainfluenza virus 2, parainfluenza virus 3, parainfluenza virus 4, respiratory syncytial virus, Bordetella pertussis, Chlamydia pneumoniae, and Mycoplasma pneumoniae. Two new targets are included in the FilmArray RP2: Middle East respiratory syndrome coronavirus and Bordetella parapertussis. This study provides data from a multicenter evaluation of 1,612 prospectively collected NPS samples, with performance compared to that of the FilmArray RP or PCR and sequencing. The overall percent agreement between the FilmArray RP2 and the comparator testing was 99.2%. The RP2 demonstrated a positive percent agreement of 91.7% or greater for detection of all but three analytes: coronavirus OC43, B. parapertussis, and B. pertussis. The FilmArray RP2 also demonstrated a negative percent agreement of ≥93.8% for all analytes. Of note, the adenovirus assay detects all genotypes, with a demonstrated increase in sensitivity. The FilmArray RP2 represents a significant improvement over the FilmArray RP, with a substantially shorter run time that could aid in the diagnosis of respiratory infections in a variety of clinical scenarios.

Multicenter Evaluation of the ePlex Respiratory Pathogen Panel for the Detection of Viral and Bacterial Respiratory Tract Pathogens in Nasopharyngeal Swabs

The performance of the new ePlex Respiratory Pathogen (RP) panel (GenMark Diagnostics) for the simultaneous detection of 19 viruses (influenza A virus; influenza A H1 virus; influenza A 2009 H1 virus; influenza A H3 virus; influenza B virus; adenovirus; coronaviruses [HKU1, OC43, NL63, and 229E]; human rhinovirus/enterovirus; human metapneumovirus; parainfluenza viruses 1, 2, 3, and 4; and respiratory syncytial virus [RSV] [RSV subtype A and RSV subtype B]) and 2 bacteria (Mycoplasma pneumoniae and Chlamydia pneumoniae) was evaluated. Prospectively and retrospectively collected nasopharyngeal swab (NPS) specimens (n = 2,908) were evaluated by using the ePlex RP panel, with the bioMérieux/BioFire FilmArray Respiratory Panel (BioFire RP) as the comparator method. Discordance analysis was performed by using target-specific PCRs and bidirectional sequencing. The reproducibility of the assay was evaluated by using reproducibility panels comprised of 6 pathogens. The overall agreement between the ePlex RP and BioFire RP results was >95% for all targets. Positive percent agreement with the BioFire RP result for viruses ranged from 85.1% (95% confidence interval [CI], 80.2% to 88.9%) to 95.1% (95% CI, 89.0% to 97.9%), while negative percent agreement values ranged from 99.5% (95% CI, 99.1% to 99.7%) to 99.8% (95% CI, 99.5% to 99.9%). Additional testing of discordant targets (12%; 349/2,908) confirmed the results of ePlex RP for 38% (131/349) of samples tested. Reproducibility was 100% for all targets tested, with the exception of adenovirus, for which reproducibilities were 91.6% at low virus concentrations and 100% at moderate virus concentrations. The ePlex RP panel offers a new, rapid, and sensitive “sample-to-answer” multiplex panel for the detection of the most common viral and bacterial respiratory pathogens.

Clinical Evaluation of the Luminex NxTAG Respiratory Pathogen Panel

An evaluation of the Luminex NxTAG Respiratory Pathogen Panel was performed on 404 clinical respiratory specimens. Clinical sensitivities and specificities of the assay compared to those of the reference methods were 80.0% to 100.0% and 98.9% to 100.0%, respectively. Correct genotyping information was provided for 95.5% of influenza virus A specimens. The closed-tube format of the assay simplified the workflow and minimized carryover contamination.

Sample-to-result molecular infectious disease assays: clinical implications, limitations and potential

Molecular infectious disease diagnostic tests have undergone major advances in the past decade and will continue to rapidly evolve. Assays have become extraordinarily simple to perform, eliminating the need for pre-analytic sample preparation and post-amplification analysis. This allows these tests to be performed in settings without sophisticated expertise in molecular biology, including locations with limited resources. Additionally, the sensitivity and specificity of these assays is superb and many offer extremely fast turn-around times. These tests have major impacts on patient care, but also have some limitations.

Protecting Newborns Against Pertussis: Treatment and Prevention Strategies

Pertussis is a potentially severe respiratory disease, which affects all age groups from young infants to older adults and is responsible for an estimated 195,000 deaths occurred globally in 2008. Active research is ongoing to better understand the pathogenesis, immunology, and diagnosis of pertussis. For diagnosis, molecular assays (e.g., polymerase chain reaction) for detection of Bordetella pertussis have become more widely available and support improved outbreak detection. In children, pertussis vaccines have been incorporated into routine immunization schedules and deployed for pertussis outbreak control. Lower levels of vaccine coverage are now being observed in communities where vaccine hesitancy is rising. Additionally, recognition that newborn babies are at risk of pertussis in the USA and UK has led to recommendations to immunize pregnant women. Among adolescents and older adults in the USA, Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular pertussis (Tdap) Vaccines are recommended, but substantial individual- and system-level barriers exist that will make achieving national Healthy People 2020 targets for immunization challenging. Current antimicrobial regimens for pertussis are focused on reducing the severity of disease, reducing rates of sequelae, and minimizing transmission of infection to susceptible individuals. Continued surveillance for pertussis will be important to identify opportunities for reducing young infants' exposure and reducing the impact of outbreaks among school-aged children. Laboratory-based surveillance for newly emerging strains of B. pertussis will be important to identify strains that may evade protection elicited by currently available vaccines. Efforts to develop new-generation pertussis vaccines should be considered now in anticipation of vaccine development programs, which may require ten or more years to deliver a licensed vaccine.

Detection of Bordetella pertussis using a PCR test in infants younger than one year old hospitalized with whooping cough in five Peruvian hospitals

OBJECTIVES

To report the incidence, epidemiology, and clinical features of Bordetella pertussis in Peruvian infants under 1 year old.

PATIENTS AND METHODS

A prospective cross-sectional study was conducted in five hospitals in Peru from January 2010 to July 2012. A total of 392 infants under 1 year old were admitted with a clinical diagnosis of whooping cough and tested for B. pertussis by PCR.

RESULTS

The pertussis toxin and IS481 genes were detected in 39.54% (155/392) of the cases. Infants aged less than 3 months were the most affected, with a prevalence of 73.55% (114/155). The most common household contact was the mother, identified in 20% (31/155) of cases. Paroxysm of coughing (89.03%, 138/155), cyanosis (68.39%, 106/155), respiratory distress (67.09%, 104/155), and breastfeeding difficulties (39.35%, 61/155) were the most frequent symptoms reported.

CONCLUSION

An increase in pertussis cases has been reported in recent years in Peru, despite national immunization efforts. Surveillance with PCR for B. pertussis is essential, especially in infants less than 1 year old, in whom a higher rate of disease-related complications and higher mortality have been reported.