Serotypes and Genotypes of Invasive <i>Streptococcus pneumoniae</i> Before and After PCV10 Implementation in Southern Brazil

<div><p>To reduce the burden of pneumococcal diseases, different formulations of pneumococcal conjugate vaccines (PCV) have been introduced in many countries. In Brazil, PCV10 has been available since 2010. We aimed to analyze the serotype and genetic composition of invasive pneumococci from Brazil in pre- and post- vaccination periods (2007–2012). Antibiotic susceptibility was determined and genotypes of macrolide and fluoroquinolone resistance were characterized. The genotypes of isolates of the most frequent serotypes were determined by multilocus sequence typing. The study included 325 isolates, which were primarily recovered from blood. The most common serotypes recovered were 14, 3, 4, 23F, 7F, 9V, 12F, 20, 19F, 8, 19A, and 5. Thirty-eight pneumococci (11.7%) were from children ≤5 years old. Considering the overall population, PCV10 and PCV13 serotype coverage was 50.1% and 64.9%, respectively. During the pre-vaccine period, isolates with serotypes belonging to the PVC10 represented 51.5% (100/194), whereas in the post vaccine they represented 48.0% (63/131). PCV13 serotypes represented 67.5% (131/194) and 59.2% (77/131) of total for pre- and post-vaccination periods, respectively. Seventy different sequence types [STs] were found, accounting for 9 clonal complexes [CCs] and 45 singletons. Eight STs (156, 180, 218, 8889, 53, 191, 770, and 4967) represented the majority (51.5%) of isolates. Fifty STs were associated with the pre-vaccination period (27 exclusive) and 43 (20 exclusive) with the post-vaccination period; 23 STs were identified in both periods. Some serotypes were particularly clonal (7F, 8, 12F, 20). Non-susceptibility to penicillin was associated with serotype 19A, CC320. Erythromycin resistance was heterogeneous when considering serotype and ST. A single serotype 23F (ST4967) isolate was resistant to levofloxacin. Continued surveillance is required to determine vaccine impact and to monitor changes in pneumococcal population biology post-PCV10 introduction in Brazil.</p></div

Distribution of serotypes in pre- and post-vaccination period among pneumococci recovered from IPD, during 2007–2012.

<p>Black bars represent pre-PCV10 and gray bars post-PCV10.</p

Population structure of invasive <i>S. pneumoniae</i> collected from 2007 to 2012.

<p>Black circles: pre-vaccine isolates; Green circles: post-vaccine isolates; pink circles: isolates present in both pre and post vaccine years; Blue circles: the ancestor of the CC.</p

Serotypes and STs observed among 231 pneumococci recovered from IPD (2007–2012).

<p>Serotypes and STs observed among 231 pneumococci recovered from IPD (2007–2012).</p

Distribution of serotypes belonging to PCV10 among invasive pneumococci recovered from 2007 to 2012 (the distribution of all serotypes is demonstrated on the Table S1).

<p>*Pre-vaccination period;</p><p>**post-vaccination period;</p>#<p>OR: odds ratio.</p><p>Distribution of serotypes belonging to PCV10 among invasive pneumococci recovered from 2007 to 2012 (the distribution of all serotypes is demonstrated on the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0111129#pone.0111129.s001" target="_blank">Table S1</a>).</p

New STs and their relationship with serotypes and STs in the database at MLST website (MLST database – accessed 19^th October, 2013).

<p>*Pre: pre-vaccination; Post: post-vaccination;</p><p>**More frequent ST and/or the ones isolated in Brazil;</p>#<p>8897 is DLV of STs 2781 (serotype 6B) and 8248 (serotype 6A/B), isolated previously in Brazil;</p>##<p>8881 is DLV of STs 9 (serotype 14) and 15 (serotype 14). The first ST was previously isolated in many countries, as the second one, which was also related to Brazilian isolates.</p><p>New STs and their relationship with serotypes and STs in the database at MLST website (MLST database – accessed 19^th October, 2013).</p

PCV10 coverage over the years of the study (2007–2012), considering epidemiologically relevant age groups.

<p>*included one isolate each year (2009 and 2010) recovered from a patient identified as “pediatric”: serotype 14 for both year.</p><p>PCV10 coverage over the years of the study (2007–2012), considering epidemiologically relevant age groups.</p

Characteristics of pneumococci recovered from IPD showing non-susceptibility to erythromycin, levofloxacin, ceftriaxone and penicillin.

<p>*Genotype for erythromycin and levofloxacin resistance only; Penicillin (PEN), ceftriaxone (CRO), erythromycin (ERY) and levofloxacin (LEV) MICs.</p><p>Characteristics of pneumococci recovered from IPD showing non-susceptibility to erythromycin, levofloxacin, ceftriaxone and penicillin.</p

Isolates representing possible capsular switching associated with pre-existing STs, considering MLST database (accessed 19^th October, 2013).

<p>*ND: Not defined;</p><p>**Taiwan, Korea, South Korea, Malaysia, France, Germany.</p><p>Isolates representing possible capsular switching associated with pre-existing STs, considering MLST database (accessed 19^th October, 2013).</p