Pneumococcal Serotype Distribution Research Articles

Serotype distribution and penicillin-non-susceptibility of Streptococcus pneumoniae causing invasive diseases in Kuwait: A 10-year study of impact of pneumococcal conjugate vaccines

ABSTRACTObjectives: The impact of PCV7 and PCV13 on pneumococcal infections in Kuwait is not known. Therefore we evaluated the impact on pneumococcal serotype distribution and penicillin-non-susceptibility in invasive infections in Kuwait.Methods: Children < 2 y were given PCV7 from Aug 2006 to Jul 2010 (period I), and PCV13 from Aug 2010 to Jul 2013 (period II) with a pre-vaccination period from Aug 2003 to Jul 2006. Serotype and penicillin-non-susceptibility of blood and cerebrospinal fluid isolates from all ages were determined.Results: In <2 y old children, even with a small number of infections, a drop in PCV7 serotypes was evident after vaccination. For all age groups combined, in the pre-vaccination period, PCV7, PCV13, PCV13 non-PCV7 serotypes and penicillin-non-susceptibility constituted 53.2%, 72.6%, 19.4% and 6.5% of the isolates respectively. PCV7, PCV13 non-PCV7 serotypes and penicillin-non-susceptibility changed to 32.7%, 28.2% and 7.3% (period I) and 6.6%, 22.2% and 8.9% (period II).Conclusions: Vaccines reduced invasive infections due to PCV7 serotypes.

Serotypes and Antibiotic Susceptibility of Streptococcus pneumoniae Isolates from Invasive Pneumococcal Disease and Asymptomatic Carriage in a Pre-vaccination Period, in Algeria.

In Algeria, few data is available concerning the distribution of pneumococcal serotypes and respective antibiotic resistance for the current pre-vaccination period, which is a public health concern. We identified the most frequent Streptococcus pneumoniae serogroup/types implicated in invasive pneumococcal disease (IPD; n = 80) and carriage (n = 138) in Algerian children younger than 5 years old. Serogroup/types of 78 IPD isolates were identified by capsular typing using a sequential multiplex PCR. Overall, serotypes 14, 19F, 6B, 23F, 18C, 1, 5, 7F, 19A, and 3 (55% of PCV7 serotypes, 71.3% of PCV10, and 90% of PCV13) were identified. Additionally, 7.5% of the non-vaccine serotypes 6C, 9N/L, 20, 24F, 35B, and 35F, were observed. In the case of S. pneumoniae asymptomatic children carriers, the most common serogroup/types were 6B, 14, 19F, 23F, 4, 9V/A, 1, 19A, 6A, and 3 (42.7% of PCV7 serotypes, 44.2% of PCV10, and 58% of PCV13). For 6.1% of the cases co-colonization was detected. Serotypes 14, 1, 5, and 19A were more implicated in IPD (p < 0.01), whereas serotype 6A was exclusively isolated from carriers (p < 0.01). Deaths associated with IPD were related to serotypes 19A, 14, 18C, and one non-typeable isolate. Among IPD related to vaccine serotypes, the rates of penicillin non-susceptible isolates were higher in no meningitis cases (80%) than in meningitis (66.7%), with serotypes 14, 19A, 19F, and 23F presenting the highest MIC levels (>2μg/ml). Resistance to cefotaxime was higher in isolates from meningitis (40.5%); however, resistance to erythromycin and co-trimoxazole (>40%) was more pronounced in no-meningeal forms. Overall, our results showed that PCV13 conjugate vaccine would cover up to 90% of the circulating isolates associated with IPD in Algeria, highlighting the importance of monitoring the frequency of S. pneumoniae serogroups/types during pre- and post-vaccination periods.

Cocolonization of Pneumococcal Serotypes in Healthy Children Attending Day Care Centers: Molecular Versus Conventional Methods.

Pneumococci are common colonizer, especially of children, and cocolonization of different serotypes is an important factor for intraspecies genetic exchange. The aim of this study was to analyze pneumococcal carriage and serotype distribution in unvaccinated healthy children in Iceland and compare conventional culture methods and molecular methods using DNA extracted directly from the samples. Nasopharyngeal swabs were obtained from 514 children aged 2-6 year attending day care centers in Reykjavik in 2009. The swabs were selectively cultured for pneumococci and the isolates serotyped using latex agglutination. DNA was also extracted directly from the swabs and serotyped using a multiplex PCR panel designed to detect vaccine serotypes and the most commonly carried non-vaccine serotypes. Pneumococcal carriage was detected in 391 (76.1%) of the children using polymerase chain reaction (PCR) and in 371 (72.2%) using conventional methods. Cocolonization was detected in 92 (23.5%) of the carriers when PCR method was used and in 30 (8.1%) when conventional methods were used, detecting 500 and 401 strains, respectively (P < 0.0001). The most common serotypes were 23F, 19A, 6B, 6A and 19F, rates 13-8%. The number of isolates of serotypes included in the 10-valent and 13-valent vaccines and detected by PCR were 234 (58.4%) and 363 (90.5%), respectively and by conventional methods 186 (46.4%) and 293 (73.1%), respectively. Cocolonization was detected in a fourth of the children carrying pneumococci using DNA extracted directly from nasopharyngeal swabs. The rate of carriage was very high, but no serotype dominated, and the children were commonly colonized by vaccine serotypes, especially cocolonized children.

Pan India distribution of pneumococcal serotypes (PIDOPS) causing invasive pneumococcal disease and pneumonia in children between 6 weeks and 5 years and their antimicrobial resistance – Phase I

Abstract Analysis of the published pneumococcal surveillance reports reveals variability and lack of long-term studies from India. The variability relates to case definition, characterization, surveillance, and laboratory methods. In the backdrop of scarcity of data, a multisite surveillance network study, PIDOPS Phase I, was launched in the year 2013 at 7 institutional and 51 sentinel sites. During the course of the study, novel molecular techniques were developed and standardized for rapid, accurate detection and typing. 1504 serum samples from IPD pediatric subjects were analyzed with automated blood culture and qmPCR. 108 isolates and 456 positive serum samples were serotyped by Quellung and PCRSeqTyping, respectively. The isolates were tested for their MIC and Multilocus Sequence Typing. The strength of this study was the use of advanced techniques providing comprehensive surveillance data and development of pan India referral system before the introduction of pneumococcal conjugate vaccine in the national immunization program.

The Relevance of a Novel Quantitative Assay to Detect up to 40 Major Streptococcus pneumoniae Serotypes Directly in Clinical Nasopharyngeal and Blood Specimens.

For epidemiological and surveillance purposes, it is relevant to monitor the distribution and dynamics of Streptococcus pneumoniae serotypes. Conventional serotyping methods do not provide rapid or quantitative information on serotype loads. Quantitative serotyping may enable prediction of the invasiveness of a specific serotype compared to other serotypes carried. Here, we describe a novel, rapid multiplex real-time PCR assay for identification and quantification of the 40 most prevalent pneumococcal serotypes and the assay impacts in pneumonia specimens from emerging and developing countries. Eleven multiplex PCR to detect 40 serotypes or serogroups were optimized. Quantification was enabled by reference to standard dilutions of known bacterial load. Performance of the assay was evaluated to specifically type and quantify S. pneumoniae in nasopharyngeal and blood samples from adult and pediatric patients hospitalized with pneumonia (n = 664) from five different countries. Serogroup 6 was widely represented in nasopharyngeal specimens from all five cohorts. The most frequent serotypes in the French, South African, and Brazilian cohorts were 1 and 7A/F, 3 and 19F, and 14, respectively. When both samples were available, the serotype in blood was always present as carriage with other serotypes in the nasopharynx. Moreover, the ability of a serotype to invade the bloodstream may be linked to its nasopharyngeal load. The mean nasopharyngeal concentration of the serotypes that moved to the blood was 3 log-fold higher than the ones only found in the nasopharynx. This novel, rapid, quantitative assay may potentially predict some of the S. pneumoniae serotypes invasiveness and assessment of pneumococcal serotype distribution.

Pneumococcal Mastoiditis in Children Before and After the Introduction of Conjugate Pneumococcal Vaccines.

To determine whether serotype distribution and antibiotic resistance of Streptococcus pneumoniae acute mastoiditis (AM) in children have changed in the post pneumococcal conjugate vaccines (PCVs) era. Medical records of pneumococcal AM cases, in a tertiary pediatric hospital were reviewed from January 1999 to December 2014. S. pneumoniae isolates were serotyped using the quellung reaction and tested for antibiotic susceptibility by E-test and for macrolide resistance genes by polymerase chain reaction. Among 334 children with AM, S. pneumoniae was isolated from 89 (26.6%) with median age 22 months (interquartile range: 12-30 months). S. pneumoniae was recovered from ear fluid (58%), mastoid specimens (35.2%) and blood (6.8%). Resistance to penicillin, erythromycin and clindamycin was 12.4%, 49.4% and 18%, respectively. Distribution of pneumococcal serotypes before (1999-2005), after the introduction of PCV7 (2006-2010) and after PCV13 (2011-2014) was found: for the PCV7 serotypes 81%, 25% and 0% (P < 0.0001), for PCV13 additional serotypes 16.3%, 70.8% and 63.6% (P < 0.0001) and for non-PCV serotypes 2.3%, 4.1% and 36.3% (P = 0.0002), respectively. Significant increase was detected for the serotype 19A after PCV7, and this trend was not changed after PCV13 (2.3%, 50% and 50%, respectively; P < 0.0001). A significant proportion of resistant isolates to penicillin (54.5%) and erythromycin (34.8%) was identified as 19A. After the introduction of PCV7, a significant increase of serotype 19A and replacement of PCVs serotypes was identified. After PCV13, the overall proportion of pneumococcal mastoiditis and the incidence of serotype 19A were not significantly declined. A significant proportion of resistant isolates to penicillin and erythromycin is attributed to serotype 19A.

Active hospital-based surveillance of invasive pneumococcal disease and clinical pneumonia in infants and young children in two Polish counties.

IntroductionInvasive pneumococcal disease (IPD) incidence, serotype distribution, and antibiotic susceptibility of Streptococcus pneumoniae were estimated in children aged 28 days to < 60 months.Material and methodsOne-year prospective, hospital-based surveillance was conducted starting on February 15, 2008, at two children's hospitals serving the city and surrounding county of Poznań and Poznański, Poland. Eligible children had fever ≥ 39.0°C or physician-suspected IPD. Blood cultures were obtained from all children, cerebrospinal fluid in suspected meningitis cases, and chest radiographs (CXRs) in suspected pneumonia cases.ResultsSeven of 1,581 eligible children had confirmed IPD. Estimated IPD incidence per 100,000 children was 11.89 (95% CI: 4.78–24.50) overall and 20.1 (95% CI: 6.52–46.84) in subjects aged 28 days to < 24 months. One S. pneumoniae isolate of each of the following serotypes was obtained: 6B, 14, 23A, 23F, and 33F. Two isolates were resistant to both trimethoprim-sulfamethoxazole and erythromycin. Clinical pneumonia incidence among children aged 28 days to < 24 months and 24 months to < 60 months was 3,151.3 (95% CI: 2934.7–3379.7) and 962.7 (95% CI: 861.2–10,072.9) per 100,000 children, respectively. CXR-confirmed pneumonia rates in the same groups were 1,035.7 (95% CI: 913.2–1,170.1) and 379.8 (95% CI: 317.1–451.3) per 100,000 children, respectively.ConclusionsIPD is an important cause of morbidity in Poznań and Poznański county, Poland. Among participants aged < 5 years with fever or suspected IPD, pneumonia was the most common diagnosis and was highest in children aged < 24 months.

Distribution of PCV13 Pneumococcal Serotypes in Patients With Community-Acquired Pneumonia Presenting at 20 United States Hospitals

Distribution of PCV13 Pneumococcal Serotypes in Patients With Community-Acquired Pneumonia Presenting at 20 United States Hospitals

Pneumococcal serotype distribution in adults with invasive disease and in carrier children in Italy: Should we expect herd protection of adults through infants' vaccination?

ABSTRACTThe 7-valent pneumococcal conjugate vaccine (PCV7) produced a significant herd protection in unvaccinated adult population mostly because of pneumococcus carriage decrease in vaccinated children. It is not known if the 13-valent pneumococcal vaccine can give similar effect on adults. Aims of the work were to evaluate whether the 6 additional serotypes are present in nasopharynx of children and serotype distribution in invasive pneumococcal infections (IPD) in adults. Realtime-PCR was used to evaluate pneumococcal serotypes in adults with confirmed IPD and in nasopharyngeal swabs (NP) from 629 children not vaccinated or vaccinated with PCV7 and resident in the same geographical areas. Two hundred twenty-one patients (116 males, median 67.9 years) with IPD were studied (pneumonia n = 103, meningitis n = 61 sepsis n = 50, other n = 7). Two hundred twelve were serotyped. The most frequent serotypes were 3, (31/212; 14.6%), 19A, (19/212; 9.0%), 12 (17/212; 8.0%), 7F, (14/212; 6.6%). In NP of children, the frequency of those serotypes causing over 50% of IPD in adults was very low, ranging from 0.48% for serotype 7F to 7.9% for serotype 19A. On the other side serotype 5, very frequent in NP (18.7%) caused <1% IPD. In conclusion serotypes causing IPD in adults are very rarely found in children NP. We suggest that herd protection obtainable with the additional 6 serotypes included in PCV13 may be more limited than that demonstrated with PCV7 in the past. In order to reduce the burden of disease in adults, adults should be offered a specific vaccination program with highly immunogenic PCV.

13-Valent Pneumococcal Conjugate Vaccine: A Review of Its Use in Adults.

The 13-valent pneumococcal conjugate vaccine (Prevenar 13(®), Prevnar 13(®)) [PCV13] consists of 13 serotype-specific polysaccharides of Streptococcus pneumoniae (pneumococcus), each covalently conjugated to a non-toxic immunogenic carrier protein. PCV13 has a well established immunogenicity and tolerability profile in adults, particularly those ≥50 years of age. Results of CAPiTA, a randomized, double-blind, placebo-controlled trial in >84,000 older adults aged ≥65 years, showed that PCV13 was effective in preventing vaccine-type pneumococcal community-acquired pneumonia (CAP), vaccine-type pneumococcal nonbacteraemic (noninvasive) CAP and vaccine-type invasive pneumococcal disease (IPD). These findings, along with changes in pneumococcal serotype distribution and epidemiology of pneumococcal disease, prompted the US Advisory Committee on Immunization Practices (ACIP) to recommend PCV13 in series with 23-valent pneumococcal polysaccharide vaccine (PPVS23) for all adults aged ≥65 years. PCV13 also has a role in preventing pneumococcal disease (pneumonia and IPD) in younger adults with immunocompromising conditions and potentially in those with other underlying medical conditions that increase the risk of pneumococcal disease.

Cost-effectiveness analysis of the available pneumococcal conjugated vaccines for children under five years in Colombia.

BackgroundPneumococcal diseases in children under five years are common and preventable. In Colombia there are two pneumococcal conjugate vaccines (PCV) that have proved clinical efficacy. The aim was to estimate the cost-effectiveness of 13-valent PCV (PCV13) and 10-valent PCV (PCV10) in terms of prevention of Invasive Pneumococcal Diseases (IPD), radiologically-confirmed pneumonia, and their related mortality, as well as, acute otitis media (AOM) in a cohort of newborns in Colombia.MethodsWe developed an analytical decision tree model with national data including the distribution of pneumococcal serotypes in Colombia between 2009 and 2013. A simulation of vaccination of 90% of newborns in Colombia took place with a time horizon of 5 years. The analysis was done from the Colombian health system perspective. Vaccines efficacy parameters were measured as life-years gained (LYG) and avoided morbidity by pneumococcal diseases; they were determined by a systematic review of literature. A health insurance company provided the costs. A probabilistic and a univariate sensitivity analysis for epidemiological, efficacy and cost parameters were done.ResultsAfter 5 years projection, PCV13 would prevent 437 deaths due to pneumococcal infections versus 321 that would be prevented by PCV10, compared to no vaccination. PCV13 would generate 25 396 LYG, and PCV10 would generate 18 708 LYG. Medical costs avoided would be US$ 19 479 395 for PCV13 and US$ 13 703 271 for PCV10. Compared to no vaccination, PCV13 and PCV10 were cost-effective, with an incremental cost-effectiveness ratio (ICER) of US$ 489.26 and US$ 813.41 per additional LYG, respectively; besides, PCV13 was dominant over PCV10 due to lower costs and better outcomes.ConclusionPCV13 is a cost-saving strategy compared with PCV10, as part of a universal coverage vaccination program in Colombian children under one year. PCV13 is expected to lead to a greater decrement in infant mortality from pneumococcal diseases, and a higher cost saving by preventing more pneumococcal diseases compared with PCV10 in a 5 years projection.

Pneumococcal infections at Hajj: current knowledge gaps.

Hajj attendance increases the risk of respiratory infections including pneumonia. Streptococcus pneumoniae is a frequently identified pathogen, found in about 10% of respiratory tract samples of symptomatic Hajj pilgrims; and at least 20% of these isolates are penicillin resistant. However, the burden of pneumococcal disease at Hajj is not precisely defined at serotypic level, and it is postulated that due to intense mixing of pilgrims the distribution of pneumococcal serotypes at Hajj could be different from pilgrims' country of origin or of Saudi Arabia. In Saudi Arabia, the most prevalent pneumococcal serotypes are 23F, 6B, 19F, 18C, 4, 14, and 19A, and 90% of the serotypes are covered by 13-valent pneumococcal conjugate vaccine (PCV-13) as well as 23-valent pneumococcal polysaccharide vaccine (PPV-23). However, due to lack of Hajj-specific data, the Saudi Arabian Ministry of Health has not yet recommended pneumococcal vaccine for pilgrims, and the immunisation recommendation and uptake vary greatly across countries. As at least one third of Hajj pilgrims are 'at risk' of pneumococcal disease either by virtue of age or pre-existing medical conditions, consideration should be given to vaccinating high risk pilgrims against pneumococcal disease. Other preventive measures such as smoking cessation, pollution reduction and vaccinations against influenza and pertussis should also be considered. Precisely defining the epidemiology of pneumococcal disease to identify an optimum vaccination schedule for Hajj pilgrims is a current research priority.

Hospital-based surveillance of invasive pneumococcal disease and pneumonia in South Bangalore, India.

To estimate the incidence of invasive pneumococcal disease and pneumonia, distribution of pneumococcal serotypes, and antibiotic susceptibility in children aged 28 days to <60 months. Hospital-based surveillance. South Bangalore, India. 9950 children aged 28 days to <60 months with clinical suspicion of invasive pneumococcal disease or pneumonia. The estimated at-risk population included 224,966 children <5 years of age. Forty cases of invasive pneumococcal disease were identified. Estimated invasive pneumococcal disease incidence was 17.8/100,000 with incidence being highest among children aged 6 months to <12 months (49.9/100,000). Clinical pneumonia syndrome was the most frequent diagnosis (12.5/100,000). Pneumococcal serotypes included: 6A (n=6, 16.7%); 14 (n=5, 13.9%); 5 (n=4, 11.1%); 6B (n=4, 11.1%); 1, 18C, and 19A (n=3 each, 8.3%); 9V (n=2, 5.6%); and 3, 4, 10C, 18A, 18F, and 19F (n=1 each, 2.8%). Serotypes 6A, 14, 6B, 1, 18C, 19A, 9V, 4, 10C, and 18A showed antibiotic resistance. Clinical pneumonia incidence was 2109/100,000, with incidence being highest among children aged 28 days to <6 months (5033/100,000). Chest radiograph-confirmed pneumonia incidence was 1114/100,000, with incidence being highest among children aged 28 days to <6 months (2413/100,000). Invasive pneumococcal disease and pneumonia were found to be common causes of morbidity in young children living in South Bangalore, India.

Bacterial etiology of acute otitis media and characterization of pneumococcal serotypes and genotypes among children in Moscow, Russia.

We aimed to describe bacterial etiology of acute otitis media (AOM) and characterize resistance, serotypes and genotype profiles of AOM-causing pneumococci recovered in Moscow children. Children with AOM and an available middle ear fluid specimen were prospectively enrolled in this study. Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae and Moraxella catarrhalis were considered as true otopathogens. All pneumococcal isolates were serotyped using the Quellung reaction; multidrug-resistant (MDR) pneumococci underwent multilocus sequence typing. In 172 of 541 enrolled AOM patients (32%) at least 1 otopathogen was recovered, with S. pneumoniae having the highest rate of 63% (109/172). When adjusted for antibiotic treatment before sampling, in untreated patients the rate of culture-positive AOM was 35% (124/352), S. pneumoniae had a prevalence of 69% (86/124), S. pyogenes 19% (24/124), H. influenzae 13% (16/124) and M. catarrhalis 9% (11/124). Among 107 examined pneumococci, 45% were penicillin-nonsusceptible, 34 and 30% were resistant to erythromycin and clindamycin, respectively; 30% had an MDR phenotype, but no amoxicillin-resistant isolates were found. Ten of 32 (31%) MDR pneumococci related to clonal complex 320, the remaining isolates belonged to 7 different clonal complex. Six leading serotypes were 19F (27%), 3 (12%), 6B (11%), 14 (11%), 19A (9%) and 23F (8%); overall polysaccharide conjugate vaccine13 coverage was 93%. S. pneumoniae, the leading bacterial AOM pathogen in Moscow children, is characterized by a substantial rate of antibiotic nonsusceptibility and clonality. A polysaccharide conjugate vaccine with expanded coverage seems to fit the current AOM pneumococcal serotype distribution in Russia better.

Nasopharyngeal Pneumococcal Serotypes Before and After Mass Azithromycin Distributions for Trachoma.

Twenty-four Ethiopian communities were randomized to receive either (1) quarterly mass azithromycin distributions for trachoma for 1 year or (2) delayed treatment. Nasopharyngeal swabs collected from separate cross-sectional population-based samples of children were processed for Streptococcus pneumoniae Mass azithromycin did not significantly alter the pneumococcal serotype distribution, and hence it would not be expected to alter vaccine coverage.

Measuring the effects of pneumococcal conjugate vaccine (PCV7) on Streptococcus pneumoniae carriage and antibiotic resistance: The Palestinian-Israeli Collaborative Research (PICR)

BackgroundThe Palestinian-Israeli Collaborative Research (PICR) cross-conflict setting provided a unique opportunity to study overall and indirect effects of pneumococcal conjugate vaccine (PCV7), in two closely related Palestinian populations governed by two distinct health authorities with distinct vaccination policies. Here, PCV7 effects on pneumococcal carriage, serotype distribution and antibiotic resistance are reported. MethodsAnnual cross-sectional surveys of pneumococcal carriage were performed during 2009–2011 among Palestinian children (≤5 years) (a) under Palestinian-Authority (PA) health policy (Ramallah, Nablus and Bethlehem), where PCV7 was unlicensed (b) under Israeli health policy (East-Jerusalem (EJ)) where PCV7 was rapidly implemented from July 2009. Clinical data were collected, pneumococci identified and characterized for antibiotic susceptibilities and serotype. Analyses included multivariate logistic models with an interaction term for PCV7-effect. ResultsAltogether, 2755 children from PA (n=1772) and EJ (n=983) were enrolled, of which ∼30% were pneumococcal carriers. While overall carriage was not affected by vaccination policy, carriage of vaccine-type (VT7) strains decreased from 52% to 22% (p<0.001) in EJ, where PCV was implemented, but not in PA. This was accompanied by an increase in non-VT13 strains from 34% to 65% (p<0.001) in EJ, but not in PA. Furthermore, within two years post-PCV7 introduction, proportion of multi-drug resistant strains, which was initially 23% in both populations, decreased significantly in EJ, to 10%, while simultaneously it increased in PA to 33% (p<0.001). Similar trends were observed for resistance to most antibiotic groups. The proportion of resistant isolates among non-VT13 strains did not change during the study period. ConclusionsThe unique study design distinguishes secular and seasonal effects from true vaccine effects. While PCV7 did not affect overall pneumococcal carriage rate, VT7 strains, many of which were antibiotic resistant decreased and were replaced by non-VT13 strains, which were mostly not antibiotic resistant, resulting in a net decrease in antibiotic resistance.

Evolution of pneumococcal infections in adult patients during a four-year period after vaccination of a pediatric population with 13-valent pneumococcal conjugate vaccine

To describe the distribution of vaccine and non-vaccine pneumococcal serotypes from adult patients for different clinical scenarios, after the introduction of the 13-valent pneumococcal conjugate vaccine (PCV-13) for children. This was a prospective study of pneumococcal infections in adult patients (January 2010 to April 2014) in Hospital Son Llàtzer, Mallorca (Spain). Two different periods of time were compared, the first before (first period) and the second after (second period) the introduction of PCV-13. Information related to clinical characteristics, outcomes of infection, pneumococcal serotypes, and antibiotic susceptibility was collected. We studied 407 episodes (371 patients), 201 in the first period and 206 in the second period. The majority of patients were male; the median patient age was 68 (range 15-99) years. Infections due to PCV-13 serotypes decreased from 59.7% to 47.6% (p=0.014), mainly serotypes 3, 7, 18C, 19F, and 23F. In the second period, PCV-13 serotypes were the cause of pneumonia in 58.2% of cases and in 40.8% of invasive infections, but these serotypes were not related with any outcome variable. No differences in hospital or intensive care unit admission, severity, or mortality were observed between the two periods. Susceptibility to penicillin (98.2% vs. 95.1%, p=0.03) and amoxicillin (96.5% vs. 91%, p=0.007) was slightly higher in the first period. Although a reduction in infections due to vaccine serotypes was observed, close to half of infections in adult patients were caused by PCV-13 serotypes. Even after pediatric vaccination with PCV-13, vaccine serotypes were still responsible for most pneumonia and invasive disease, underscoring the importance of implementing current guidelines and extending vaccination to other risk groups.

Changes in the incidence of Streptococcus pneumoniae bacteremia and its serotypes over 10 years in one hospital in South Korea

Here, we examined the distribution of pneumococcal serotypes and the antibiotic susceptibility of Streptococcus pneumoniae in clinical blood isolates. The serotypes of 91 S. pneumoniae blood isolates, collected from January 2003 to March 2014, were identified by multiplex PCR and sequencing. The most common serotypes were 19F, 19A, 3, 4, and 14, accounting for 53.8% of the total. The serotype coverage rates of pneumococcal conjugated vaccine (PCV) 7, PCV10, and PCV13 were different during three test periods: 38.7%, 70.9%, and 93.5% in period I (2003–2005), 46.8%, 50.0%, and 75.0% in period II (2006–2008), and 28.5%, 32.1%, and 64.2% in period III (2009–2014), respectively. By contrast, the number of non-PCV13 serotypes increased from 6.4% in period I to 25% and 35.7% in periods II and III, respectively. The susceptibility of non-PCV13 serotypes to antimicrobial agents (penicillin, erythromycin, cefotaxime, and meropenem) was higher than that of PCV serotypes. In particular, non-PCV13 serotypes showed 100% and 95% susceptibility to penicillin and cefotaxime, respectively. Serotypes 19A and 19F showed high prevalence (79.1%) among 24 multi-drug resistant (MDR) isolates. Notably, all serotype 19A isolates were MDR. From January 2003 to March 2014, the proportion of non-PCV13 serotype pneumococci in blood isolates increased whereas the coverage rate of PCV13 decreased. Effective pneumococcal vaccines are required to protect against MDR serotype 19A isolates and the increasing number of non-PCV13 serotypes.

P507: Invasive pneumococcal serotype distribution among adults: the gap widens

P507: Invasive pneumococcal serotype distribution among adults: the gap widens

Non-invasive pneumococcal serotypes and antimicrobial susceptibilities in a paediatric hospital in the era of conjugate vaccines

To evaluate the effects of 7-valent pneumococcal conjugate vaccine (PCV7) introduction to the routine childhood immunisation schedule in 2008 and its replacement by PCV13 in 2010 in Ireland, we surveyed the serotypes and antimicrobial susceptibilities of 339 pneumococci associated with carriage and non-invasive infection (NII) in a Dublin paediatric hospital from 2009 to 2012. Furthermore, we compared the distribution of pneumococcal serotypes collected from 2009 to 2012 to 105 NII pneumococci isolated in 2007, the year before conjugate vaccine introduction. PCV7 serotypes declined from 2007 to 2012 as follows: carriage, 67–23% (p=0.0004); conjunctivitis, 58–0% (p<0.0001); non-bacteraemic lower respiratory tract infection, 50–19% (p=0.0363) and otitis media 54–27%. Notably, antimicrobial resistant (AMR) PCV7 serotypes showed a significant decrease by the end of the study period (i.e. 2012) (p<0.0001). Compared with 2007 the overall occurrence of serotype 19A increased from 1.9 to 10% in 2010 (p=0.0132) and to 15% in 2011 (p=0.0005). Importantly, serotype 19A declined significantly from 2011 levels to an overall prevalence of 4.8% in 2012 (p=0.0243). Most striking was the significant reduction of AMR 19A (p=0.0195). Conversely, increases were observed in non-vaccine type (NVT) pneumococci in 2009–2012, of which serotypes 11A (n=30), 15B/C (n=17), 22F (n=14), 35Bn=13), non-typeable pneumococci (n=13) and 23A (n=12) were the most prevalent. Moreover, an increase in NVT non-susceptible to at least one antimicrobial in 2009–2012 was noted, attributable to serotypes 35B (n=10) and 15A (n=7). In summary, this study has shown that PCV7 and PCV13 introduction has had a positive impact on their target serotypes and antimicrobial resistance amongst pneumococci within a paediatric hospital within a short time period. However, the increase in NVT prevalence highlights the need for continued surveillance.