Geographic Distribution and Clonal Diversity of Streptococcus pneumoniae Serotype 1 Isolates

Abstract

Serotype 1 pneumococci are a major cause of serious disease and have been associated with outbreaks but are rarely carried. The high attack rate and lack of coverage of this serotype by the heptavalent conjugate vaccine prompted the characterization of a geographically diverse collection of 166 serotype 1 isolates from recent cases of invasive disease. The isolates were resolved by multilocus sequence typing into 16 clones, which clustered into three major lineages with very different geographic distributions. Lineage A isolates were exclusively from Europe and North America, lineage B isolates were predominantly from Africa and Israel, and lineage C isolates were mainly from Chile. There was no clear association between the presence of individual clones within a country and the prevalence of serotype 1 disease.

In vitro expression of the first capsule gene of Streptococcus pneumoniae, cpsA, is associated with serotype-specific colonization prevalence and invasiveness

“…This may reflect clonal differences within serotypes between geographical regions (Sandgren et al, 2004;Hanage et al, 2005). For example, clone-specific differences for invasiveness within serotype 1 have been observed (Brueggemann & Spratt, 2003). In the present study, using a clonally mixed strain collection, there was some variation in cpsA expression within serotypes between isolates with different PFGE patterns.…”

Molecular assessment of invasive Streptococcus pneumoniae serotype 1 in Brazil: evidence of clonal replacement

“…Molecular studies of serotype 1, a usually penicillin-susceptible albeit hypervirulent serotype, have been reported less frequently (Brueggemann & Spratt, 2003;Gonzalez et al, 2004;Normark et al, 2001;Porat et al, 2001). A common factor in these reports was the low genetic diversity among the isolates, which has been associated with the short duration of carriage and/or a low density of this serotype in the nasopharynx, resulting in a reduced opportunity to exchange genes between strains (Brueggemann & Spratt, 2003;Hausdorff et al, 2005).…”

“…Molecular typing studies have greatly contributed to epidemiological investigations of pneumococci, mostly focusing on the global spread of penicillin-resistant clones (Brueggemann et al, 2003;Tomasz et al, 1998). Molecular studies of serotype 1, a usually penicillin-susceptible albeit hypervirulent serotype, have been reported less frequently (Brueggemann & Spratt, 2003;Gonzalez et al, 2004;Normark et al, 2001;Porat et al, 2001).…”

“…Recently, some authors have speculated that isolates of serotype 1, which are known to have a highly invasive potential, behave as primary pathogens, whereas other capsular types demonstrate opportunistic features (Garau & Calbo, 2007;Hausdorff, 2007). Molecular typing studies have greatly contributed to epidemiological investigations of pneumococci, mostly focusing on the global spread of penicillin-resistant clones (Brueggemann et al, 2003;Tomasz et al, 1998). Molecular studies of serotype 1, a usually penicillin-susceptible albeit hypervirulent serotype, have been reported less frequently (Brueggemann & Spratt, 2003;Gonzalez et al, 2004;Normark et al, 2001;Porat et al, 2001).…”

“…Molecular typing studies have greatly contributed to epidemiological investigations of pneumococci, mostly focusing on the global spread of penicillin-resistant clones (Brueggemann et al, 2003;Tomasz et al, 1998). Molecular studies of serotype 1, a usually penicillin-susceptible albeit hypervirulent serotype, have been reported less frequently (Brueggemann & Spratt, 2003;Gonzalez et al, 2004;Normark et al, 2001;Porat et al, 2001). A common factor in these reports was the low genetic diversity among the isolates, which has been associated with the short duration of carriage and/or a low density of this serotype in the nasopharynx, resulting in a reduced opportunity to exchange genes between strains (Brueggemann & Spratt, 2003;Hausdorff et al, 2005 In a pilot study conducted to obtain information on an adequate sample size for the current study, we found that the genetic diversity of type 1 pneumococci was slightly higher in the first period (1977)(1978)(1979)(1980)(1981)(1982)(1983)(1984) compared with the last period (2001)(2002)(2003)(2004)(2005) of the study.…”