Serotype 3 is a common serotype causing invasive pneumococcal disease in children less than 5 years old, as identified by real-time PCR

Abstract

Serotype 3 is one of the most often detected pneumococcal serotypes in adults and it is associated with serious disease. In contrast, the isolation of serotype 3 by bacterial culture is unusual in children with invasive pneumococcal disease (IPD). The purpose of this study was to learn the serotype distribution of IPD, including culture-negative episodes, by using molecular methods in normal sterile samples. We studied all children<5 years of age with IPD admitted to two paediatric hospitals in Catalonia, Spain, from 2007 to 2009. A sequential real-time polymerase chain reaction (PCR) approach was added to routine methods for the detection and serotyping of pneumococcal infection. Among 257 episodes (219 pneumonia, 27 meningitis, six bacteraemia and five others), 33.5% were identified by culture and the rest, 66.5%, were detected exclusively by real-time PCR. The most common serotypes detected by culture were serotypes 1 (26.7%) and 19A (25.6%), and by real-time PCR, serotypes 1 (19.8%) and 3 (18.1%). Theoretical coverage rates by the PCV7, PCV10 and PCV13 vaccines were 10.5, 52.3 and 87.2%, respectively, for those episodes identified by culture, compared to 5.3, 31.6 and 60.2% for those identified only by real-time PCR. Multiplex real-time PCR has been shown to be useful for surveillance studies of IPD. Serotype 3 is underdiagnosed by culture and is important in paediatric IPD.

Expansion of Serotype Coverage in the Universal Pediatric Vaccination Calendar: Short-Term Effects on Age- and Serotype-Dependent Incidence of Invasive Pneumococcal Clinical Presentations in Madrid, Spain

“…In a previous study using real-time PCR for identification, serotype 3 was reported to be a common serotype causing IPD in children in Spain (26). In the present analysis, cases caused by serotype 3 represented Ͻ8% in both periods, without a significant reduction in IR in the PCV13 period.…”

Clinical, biochemical and microbiological factors associated with the prognosis of pneumococcal meningitis in children

“…PM was defined by characteristic clinical signs and symptoms (stiff or painful neck, vomiting, headache, persistent fever, bulging fontanelles) and compatible cerebrospinal fluid (CSF) alterations (CSF cell count up to 10 cells/mm 3 ) along with isolation of S. pneumoniae and/or DNA detection of pneumococcal genes by Real-Time PCR 16 in blood or cerebrospinal fluid.…”

Estimation of the invasive disease potential of Streptococcus pneumoniae in children by the use of direct capsular typing in clinical specimens

“…Detection of this serotype represented a 5-fold increase with respect to detection by culture. It is noteworthy that, although several published studies have reported a lower frequency of serotype 3 in children [22,23], a recent study in our geographical area discussed the fact that serotype 3 could have been underestimated in children due to difficulties in recovering it in culture [8].…”

“…The addition of molecular techniques to culture could provide a more exact picture of the nasopharyngeal pneumococcal population based on their ability to detect low density and multiple-serotype carriage. Particularly for the invasive disease population, the use of these techniques may lead to a change in the real prevalence of some serotypes, such as 1 and 3, that could have been underestimated due to their difficult recovery by culture [7,8].…”