Rapid diagnosis of Streptococcus pneumoniae serotype 1 by real-time PCR

Abstract number: P2201

Muñoz-Almagro C., Tarrago D., Rodriguez-Plata M.T., Esteva C., Fernandez de Sevilla M., Aguilar A.C., Garcia-Garcia J.J., Pallares R.

Streptococcus pneumoniae serotype 1 is an important cause of invasive pneumococcal disease (IPD) and can produce epidemic outbreaks. Recently, emergence of IPD (particularly empyema), caused by serotype 1 has been reported in paediatric patients. Serotyping based on the quellung reaction requires substantial training and time.

Objective: The purpose of this study was to develop a Real-Time PCR for rapid diagnosis of S. pneumoniae serotype 1 in direct samples of patients with IPD and healthy carriers.

Methods: This is a prospective study including all paediatric patients with IPD who were diagnosed by culture or pneumolisin-Real-Time PCR at our institution (January–November 2007). In addition, we also included the results of oropharyngeal swabs of a cohort of 65 healthy children studied during the same period. Real time PCR of ugd (cpsk) gene specific of serotype 1 was performed in direct samples, and the time of detection was less than 3 hours.

Results: We included a total of 71 episodes of IPD in 69 paediatric patients (range age 2 months-17 years, mean age 4 years). 30 episodes were positive by culture and Real-Time PCR and 41 only by Real-Time PCR. Serotype 1 accounted for 26% of episodes identified by culture (8 of 30 episodes) and 24% of episodes identified only by Real-Time PCR (10 of 41 episodes, p=NS). All 18 children with IPD caused by serotype 1 were diagnosed of pneumonia (16 of them with empyema). Among 65 healthy children in whom oropharyngeal swabs were cultured, 17 (26%) were pneumococcal carriers, and serotype 1 was identified in only 1 case; specific serotype 1 Real Time PCR did not identify any additional case. All pneumococcal strains of serotype 1 were susceptible to penicillin and Erythromycin.

Conclusion: Real Time PCR allows a rapid identification of Streptococcus pneumoniae serotype 1. Since this serotype is not included in the current licensed 7 valent-pneumococcal conjugate vaccine (PCV7), rapid identification of epidemic serotypes (like serotype 1) is mandatory to implement other preventive measures and control outbreaks.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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