Prevalence and Clonal Distribution of pcpA, psrP and Pilus-1 among Pediatric Isolates of Streptococcus pneumoniae

Abstract

Streptococcus pneumoniae is the leading cause of vaccine-preventable deaths globally. The objective of this study was to determine the distribution and clonal type variability of three potential vaccine antigens: Pneumococcal serine-rich repeat protein (PsrP), Pilus-1, and Pneumococcal choline binding protein A (PcpA) among pneumococcal isolates from children with invasive pneumococcal disease and healthy nasopharyngeal carriers. We studied by Real-Time PCR a total of 458 invasive pneumococcal isolates and 89 nasopharyngeal pneumococcal isolates among children (total = 547 strains) collected in Barcelona, Spain, from January 2004 to July 2010. pcpA, psrP and pilus-1 were detected in 92.8%, 51.7% and 14.4% of invasive isolates and in 92.1%, 48.3% and 18% of carrier isolates, respectively. Within individual serotypes the prevalence of psrP and pilus-1 was highly dependent on the clonal type. pcpA was highly prevalent in all strains with the exception of those belonging to serotype 3 (33.3% in serotype 3 isolates vs. 95.1% in other serotypes; P<.001). psrP was significantly more frequent in those serotypes that are less apt to be detected in carriage than in disease; 58.7% vs. 39.1% P<.001. Antibiotic resistance was associated with the presence of pilus-1 and showed a negative correlation with psrP. These results indicate that PcpA, and subsequently Psrp and Pilus-1 together might be good candidates to be used in a next-generation of multivalent pneumococcal protein vaccine.

A bivalent pneumococcal histidine triad protein D-choline-binding protein A vaccine elicits functional antibodies that passively protect mice from Streptococcus pneumoniae challenge

“…A monovalent PhtD vaccine was shown to be well tolerated and immunogenic in a phase I trial, 19 and we have confirmed that the antibodies induced by the vaccine are functional in a mouse passive protection sepsis model 20 . Likewise, immunization with PcpA, another highly conserved surface protein, 21,22 has been shown to be protective in active immunization murine models of both sepsis and pneumonia 22 . Furthermore, expression of PcpA is increased in environments low in Mn 2+ , including serum and other internal sites 22,23 …”

High prevalence of genetically-determined mannose binding lectin deficiency in young children with invasive pneumococcal disease

“…Serotypes with a high attack rate are bad colonizers, and different studies have shown that they have important virulence factors associated with the production of pleuropneumonia or other clinical manifestations of IPD [22]. Moreover, the frequency of low-MBL genotypes was observed to be especially high (46.2%) in younger children with IPD caused by opportunistic serotypes.…”

Emergence of Multidrug-Resistant Pneumococcal Serotype 35B among Children in the United States

“…In vitro studies show that serotype 35B is capable of forming substantial amounts of biofilm, similar to 19F and 19A, which may facilitate nasopharyngeal colonization and mucosal disease (35). Pneumococcal virulence factors such as pili have been found among CC558 and CC156 isolates (25,36,37). These virulence factors facilitate colonization, and they are thought to contribute to invasiveness as well (38).…”