Surveillance of pneumococcal serotype 1 carriage during an outbreak of serotype 1 invasive pneumococcal disease in central Australia 2010–2012

Abstract

BackgroundAn outbreak of serotype 1 invasive pneumococcal disease (IPD) occurred in Central Australia from October 2010 to the latter part of 2012. Surveillance of serotype 1 carriage was conducted to determine epidemiological features of asymptomatic carriage that could potentially be driving the outbreak.Methods130 patients and accompanying persons presenting at Alice Springs Hospital Emergency Department consented to nasopharyngeal swab (NPS) collection. NPS were processed by standard methods, including culture, pneumococcal lytA quantitative real-time PCR, serotype 1-specific real-time PCR and multi-locus sequence typing (MLST).ResultsPneumococcal carriage was detected in 16% of participants. Carriage was highest in the under 10 year olds from remote communities surrounding Alice Springs (75%). Four NPS were positive for serotype 1 DNA by PCR; 3 were also culture-positive for serotype 1 pneumococci. Serotype 1 isolates had atypical colony morphology on primary culture. All serotype 1 carriers were healthy children 5 to 8 years of age from remote communities. By MLST, serotype 1 isolates were ST306, as were IPD isolates associated with this outbreak.ConclusionsDuring an outbreak of serotype 1 ST306 IPD, carriage of the outbreak strain was detected in 3% NPS collected. All carriers were healthy children 5 to 8 years of age.

Molecular characterization of an Australian serotype 1Streptococcus pneumoniaeoutbreak

“…Serotype 1 is ranked among the most common invasive serotypes worldwide and is often associated with outbreaks and epidemics [3][4][5][6][7][8][9][10][11][12][13]. Unlike other pneumococci responsible for invasive pneumococcal disease (IPD), serotype 1 pneumococci are rarely found in the nasopharynx of healthy individuals in the general population [14][15][16][17][18]; however, carriage in healthy contacts has been observed during times of serotype 1 outbreaks [9], including in one carriage surveillance study undertaken during a serotype 1 outbreak which demonstrated carriage of the outbreak strain in healthy children [19].…”

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

“…Another interesting result was the detection of serotype 1 in carriers. This is a rare event even in areas where such serotype is the main cause of IPD, usually reported only during outbreaks of this serotype [26]. Some studies have suggested that the lack of serotype 1 detection in carriers could be due to the lack of techniques able to detect multiple colonization [27,28].…”

Vaccine Preventable Diseases and Vaccination Coverage in Aboriginal and Torres Strait Islander People, Australia, 2011–2015

“…70,71 The other factor contributing to relatively modest impact of 13vPCV in Aboriginal and Torres Strait Islander children is an outbreak of serotype 1 IPD among children living in central and northern parts of the country in 2010-2012. 72,73 The serotype 1 outbreak primarily affected older Aboriginal children, resulting Other sero 7vPCV 13v-non-7v 23v-non-13v…”