Relationship between serotypes, age, and clinical presentation of invasive pneumococcal disease in Madrid, Spain, after introduction of the 7-valent pneumococcal conjugate vaccine into the vaccination calendar

Impact of 13-valent pneumococcal conjugate vaccination on invasive pneumococcal disease in children under 15 years old in Madrid, Spain, 2007 to 2016: The HERACLES clinical surveillance study

Streptococcus pneumoniae is a major cause of morbidity and mortality worldwide. Using the data from the HERACLES clinical surveillance study (2007-2016), we describe the population impact of the 13-valent pneumococcal conjugate vaccine (PVC13) on invasive pneumococcal disease (IPD) in children <15 years of age in the Community of Madrid, Spain. After six years of the inclusion of PCV13 in the vaccination calendar (2010-2016), and despite changes in the Regional Immunization Programme that limited its availability, the net benefit incidence rate (IR) of IPD fell by 70.1% (IRR 0.3 [95% CI: 0.22-0.4]; p ≤ 0.001), mainly due to a significant reduction (91%) in the PCV13 serotypes (IRR 0.09 [95% CI: 0.05-0.16], p ≤ 0.001). Furthermore, no significant changes were detected in the IR of IPD caused by non-PCV13 serotypes. The IRs of the aggressive, resistant and most prevalent serotype in the analysed population, the 19A serotype, dramatically decreased from the beginning to the end of the study (98%) [IRR 0.03 (95% CI: 0.00-0.19), p ≤ 0.001], to its almost total disappearance. Remarkably, this reduction led to a pronounced decline in the percentage of cefotaxime-resistant isolates and the incidence of meningitis cases. Assessment of the clinical impact revealed a reduction in the number of all clinical presentations of IPD, confirming the effectiveness of the PCV13. Finally, PCV13 detected by PCR is predicted to have a stronger impact than the one based on culture methods, which can overlook more than 20% of cases of IPD, mainly pleural empyemas.

Serotypes and genotypes of S. pneumoniae isolates from adult invasive disease in Spain: A 5-year prospective surveillance after pediatric PCV13 licensure. The ODIN study

Serotypes/genotypes causing invasive pneumococcal disease (IPD) in adults are determined by vaccination strategies. The aim of this study was to assess the epidemiology of IPD in adults (≥18 years) after PCV13 introduction for children: serotypes, clonal complexes, antibiotic non-susceptibility and clinical presentations. We performed a prospective, clinical surveillance of hospitalized culture-confirmed IPDs in adults in nine Spanish hospitals (August 2010-June 2015). A total of 1087 culture-confirmed IPD episodes were included, of which 772 (71.0%) had bacteremic pneumonia (401 complicated/371 uncomplicated pneumonia), 122 (11.2%) meningitis, 102 (9.4%) non-focal bacteremia, 34 (3.1%) peritonitis and 57 (5.3%) others. The most common serotypes were: 3 (12.7%), 19A (8.5%), 8 (7.7%), 7F (6.3%), 1 (4.2%), 6C (4.2%), 11A (4.2%), 22F (4.2%) and 14 (4.0%). Vaccine types (PCV13 + 6C) caused 49.8% of IPD episodes, with a significant decrease over the 5-year period, and significant decreases in serotypes 6C and 7F. The most common genotypes were: CC180 (8.4%), CC191 (6.0%), and CC53 (5.0%). Vaccine types caused 53.9% (414/768) pneumonia episodes and 58.9% (235/399) complicated pneumonia, 53.4% IPD in adults <50 years (143/268), and 54.7% IPD in immunocompetent patients (337/616). Overall non-susceptibility was 25.9% to penicillin (1.1% for parenteral criteria), 24.9% to erythromycin and 2.7% to levofloxacin. CONCLUSIONS: Although the percentage of vaccine-types causing IPDs in adults significantly decreased, it remained high. Associations of vaccine types with pneumonia (with complicated pneumonia for specific serotypes), and immunocompetent patients point to the burden of IPD caused by PCV13 serotypes.

Serotype distribution of Streptococcus pneumoniae causing invasive disease in children in the post-PCV era: A systematic review and meta-analysis

BACKGROUND

Routine immunisation with pneumococcal conjugate vaccines (PCV7/10/13) has reduced invasive pneumococcal disease (IPD) due to vaccine serotypes significantly. However, an increase in disease due to non-vaccine types, or serotype replacement, has been observed. Serotypes' individual contributions to IPD play a critical role in determining the overall effects of PCVs. This study examines the distribution of pneumococcal serotypes in children to identify leading serotypes associated with IPD post-PCV introduction.

METHODS

A systematic search was performed to identify studies and surveillance reports (published between 2000 and December 2015) of pneumococcal serotypes causing childhood IPD post-PCV introduction. Serotype data were differentiated based on the PCV administered during the study period: PCV7 or higher valent PCVs (PCV10 or PCV13). Meta-analysis was conducted to estimate the proportional contributions of the most frequent serotypes in childhood IPD in each period.

RESULTS

We identified 68 studies reporting serotype data among IPD cases in children. We analysed data from 38 studies (14 countries) where PCV7 was administered and 20 (24 countries) where PCV10 or PCV13 have been introduced. Studies reported early and late periods of PCV7 administration (range: 2001∓13). In these settings, serotype 19A was the most predominant cause of childhood IPD, accounting for 21.8% (95%CI 18.6∓25.6) of cases. In countries that have introduced higher valent PCVs, study periods were largely representative of the transition and early years of PCV10 or PCV13. In these studies, the overall serotype-specific contribution of 19A was lower (14.2% 95%CI 11.1∓18.3). Overall, non-PCV13 serotypes contributed to 42.2% (95%CI 36.1∓49.5%) of childhood IPD cases. However, regional differences were noted (57.8% in North America, 71.9% in Europe, 45.9% in Western Pacific, 28.5% in Latin America, 42.7% in one African country, and 9.2% in one Eastern Mediterranean country). Predominant non-PCV13 serotypes overall were 22F, 12F, 33F, 24F, 15C, 15B, 23B, 10A, and 38 (descending order), but their rank order varied by region.

CONCLUSION

Childhood IPD is associated with a wide number of serotypes. In the early years after introduction of higher valent PCVs, non-PCV13 types caused a considerable proportion of childhood IPD. Serotype data, particularly from resource-limited countries with high burden of IPD, are needed to assess the importance of serotypes in different settings. The geographic diversity of pneumococcal serotypes highlights the importance of continued surveillance to guide vaccine design and recommendations.

Effect of the different 13-valent pneumococcal conjugate vaccination uptakes on the invasive pneumococcal disease in children: Analysis of a hospital-based and population-based surveillance study in Madrid, Spain, 2007-2015

In the Community of Madrid, the 13-valent pneumococcal conjugate vaccine (PCV13) replaced the 7-valent (PCV7) in the fully government-funded Regional Immunization Program (RIP) in May, 2010, but was later excluded in May, 2012, and included again in January, 2015. These unique changes allowed us to assess the impact of the different pneumococcal vaccination policies on PCV13 uptake in infants and on the incidence rate (IR) of invasive pneumococcal disease (IPD) in children <15 years old. In this prospective, active, surveillance study, we estimated PCV13 uptakes, IR and incidence rate ratios (IRR) for total IPD and for IPD caused by PCV13- and non-PCV13 serotypes in children <15 years, stratified by age, in four periods with different vaccination policies: fully government-funded PCV7 vaccination, fully government-funded PCV13, mixed public/private funding and only private funding. Vaccine uptakes reached 95% in periods with public-funded pneumococcal vaccination, but fell to 67% in the private funding period. Overall, IR of IPD decreased by 68% (p<0.001) in 2014–15, due to 93% reduction in the IR of PCV13-type IPD (p<0.001) without significant changes in non-PCV13-type IPD. A fully government-funded PCV13 vaccination program lead to high vaccine uptake and dramatic reductions in both overall and PCV13-type IPD IR. When this program was switched to private PCV13 vaccination, there was a fall in vaccine coverage and stagnation in the decline of PCV13-type IPD with data suggesting a weakening of herd immunity.

Using a practical molecular capsular serotype prediction strategy to investigate Streptococcus pneumoniae serotype distribution and antimicrobial resistance in Chinese local hospitalized children

BACKGROUND

China is one of ten countries with the highest prevalence rate of pneumococcal infections. However, there is limited serotype surveillance data for Streptococcus pneumoniae, especially from the community or rural regions, partly due to limited serotyping capacity because Quellung serotyping is only available in few centers in China. The aim of this study was to develop a simple, practical and economic pneumococcal serotype prediction strategy suitable for future serotype surveillance in China.

METHODS

In this study, 193 S. pneumoniae isolates were collected from hospitalized children, 96.9 % of whom were < 5 years old. The cpsB sequetyping, complemented by selective and modified USA CDC sequential multiplex-PCR, was performed on all the isolates, and serotypes 6A-6D specific PCRs were done on all serogroup 6 isolates. Based on systematic analysis of available GenBank cpsB sequences, we established a more comprehensive cpsB sequence database than originally published for cpsB sequetyping. Antibiotic susceptibility of all isolates was determined using the disk diffusion or E-test assays.

RESULTS

We built up a comprehensive S. pneumoniae serotype cpsB sequetyping database for all the 95 described serotypes first, and then developed a simple strategy for serotype prediction based on the improved cpsB sequetyping and selective multiplex-PCR. Using the developed serotype prediction strategy, 191 of 193 isolates were successfully "serotyped", and only two isolates were "non-serotypeable". Sixteen serotypes were identified among the 191 "serotypeable" isolates. The serotype distribution of the isolates from high to low was: 19 F (34.7 %), 23 F (17.1 %), 19A (11.9 %), 14 (7.3 %), 15B/15C (6.7 %), 6B (6.7 %), 6A (6.2 %), 9 V/9A (1.6 %); serotypes 6C, 3, 15 F/15A, 23A and 20 (each 1.1 %); serotypes 10B, 28 F/28A and 34 (each 0.5 %). The prevalence of parenteral penicillin resistance was 1.0 % in the non-meningitis isolates and 88.6 % in meningitis isolates. The total rate of multidrug resistance was 86.8 %.

CONCLUSIONS

The integrated cpsB sequetyping supplemented with selective mPCR and serotypes 6A-6D specific PCRs "cocktail" strategy is practical, simple and cost-effective for use in pneumococcal infection serotype surveillance in China. For hospitalized children with non-meningitis penicillin-susceptible pneumococcal infections, clinicians still can use narrow-spectrum and cheaper penicillin, using the parenteral route, rather than using broader-spectrum and more expensive antimicrobials.

Secular trends (1990-2013) in serotypes and associated non-susceptibility of S. pneumoniae isolates causing invasive disease in the pre-/post-era of pneumococcal conjugate vaccines in Spanish regions without universal paediatric pneumococcal vaccination

This study analyzed temporal trends of non-susceptibility/serotypes in invasive pneumococci from Spanish regions where pneumococcal conjugate vaccines (PCVs) were not included in paediatric immunization programmes. All invasive pneumococcal isolates voluntarily sent to the Spanish Reference Laboratory for Pneumococci (January 1990-December 2013) from hospitals located in target study regions were analyzed by age group. The PCV estimated coverage in children <24 months was correlated with 13-valent PCV (PCV13) serotypes trends. A total of 28,124 invasive isolates were analyzed: 3138 (11.2%) from children <24 months, 2161 (7.7%) from children 24-59 months, 781 (2.8%) from children 5-14 years, and 22,044 (78.4%) from adults. The estimated coverage increased from 17.6% (2002) to around 40% (2010-2013). The percentage of PCV13 serotypes among all isolates over time followed a cubic significant trend (R(2)=0.884), with an increasing trend up to 2001 followed by a decrease (more prominent from 2010 onwards). The estimated PCVs coverage was significantly correlated with the decrease in the percentage of PCV13 isolates in children <24 months (r(2)=0.824) and in adults (r(2)=0.786), mainly due to decreases in serotypes 1 and 7F in adults, and in serogroup 6 and serotypes 7F and 19A in children <24 months. None of the non-PCV13 serotypes stood out with substantial increases in the last period. This study showed that the different serotypes (and its associated non-susceptibility trends) were not equally affected by low PCVs disposition. Lack of impact in certain serotypes as serotype 1 (in children 24-59 months), 6C (in all age groups), and 19A (in adults) suggests the need for increasing vaccine coverage in the target vaccine population to increase direct and indirect protection.

[Pneumococcal vaccination coverage in at-risk children in Catalonia]

INTRODUCTION

The public health system in Catalonia only funds pneumococcal vaccination in paediatrics for children at-risk. The aim of this study was to determine pneumococcal vaccination coverage and its association with age, sociodemographic factors and other variables.

MATERIAL AND METHOD

Descriptive cross-sectional study of children aged between 2 months and 15 years old assigned to primary care centres in Catalonia and with diseases that are included for pneumococcal vaccine in the official vaccination program. The information on vaccination status and study variables were obtained from data registered in the electronic medical records in the primary care centres. An analysis was made of the association between pneumococcal vaccination and demographic and medical variables using bivariate analysis and a multiple logistic regression model. The adjusted odds ratio (aOR), with a confidence interval of 95%, was used to measure the relationships.

RESULTS

Pneumococcal vaccination coverage was 47.7%. Variables which predicted pneumococcal vaccination were: age (aOR: 9.2 [7.9-10.7] in children 2 months-2 years old; aOR 8.1 [7.0-9.3] in children 3-5 years; aOR: 4.6 [4.0-5.2] in children 6-10 years), Spanish nationality (aOR: 3.9 [3.5-4.3]), correct immunisation according to systematic immunisation schedule (aOR: 2.5 [2.1-3.0]), and number of risk conditions (aOR: 3.2 [2.5-4.1] in children with 2 or more conditions).

CONCLUSIONS

Pneumococcal vaccination coverage in children with risk conditions is low in Catalonia. Strategies need to be implemented to increase coverage.

Pneumococcal empyema and complicated pneumonias: global trends in incidence, prevalence, and serotype epidemiology

This review evaluates the serotype epidemiology of complicated pneumococcal pneumonia (CPP) during the period 1990–2012. PubMed and EMBASE were searched using the terms “empyema”, “complicated pneumonia”, “pleural infection”, “necrotizing pneumonia”, “pleural effusion”, “parapneumonic effusion”, “pneumatocele”, or “lung abscess”; “pneumococcal” or “Streptococcus pneumoniae”; and “serotype” for studies on the epidemiology of complicated pneumonias published from January 1, 1990 to October 1, 2013. Studies with data on incidence and serotypes were included; reviews, case reports, and conference abstracts were excluded. Of 152 papers, 84 fitted the inclusion criteria. A few pneumococcal serotypes were predominant causes of CPP, particularly serotypes 1, 19A, 3, 14, and 7F. CPP was a more common manifestation of pneumococcal disease among older (>2 years old) than younger children. The data support increases in both reported incidence rates and proportions of CPP in children and adults during the period 1990–2012; specific increases varied by geographic region. The proportions of serotype 3 and, particularly in Asia, serotype 19A CPP have increased, whereas most studies show declines in serotype 14. Serotype 1 has been a predominant cause of CPP since 1990, while antibiotic resistance was infrequent among serotype 1 isolates. The reported incidence and proportions of CPP among pneumonia cases steadily increased from 1990 to 2012. Several factors might account for these increases, including enhanced disease detection due to a higher index of suspicion, more sophisticated diagnostic assays, and changes in the prevalence of serotypes with capacity to invade the pleural space that were not targeted by the 7-valent pneumococcal conjugate vaccine (PCV7).

Incidence of pediatric invasive pneumococcal disease in the Island of Majorca (2008-2010), an area with non-universal vaccination, and estimations of serotype & children population coverage by available conjugate vaccines

BACKGROUND

The World Health Organization reported in 2007 that inclusion of PCV7 in national immunization programs should be seen as a priority, also encouraging countries to conduct appropriate surveillances for monitoring the impact of vaccination. These analyses should be conducted in specific geographical areas and should be aimed to evolution of invasive pneumococcal disease (IPD), by age groups, clinical presentation, and vaccine serotypes (and non-vaccine serotypes to detect possible replacement). This study aimed to monitor the evolution of IPD incidence in children <15 years requiring hospitalization in the Island of Majorca.

METHODS

A prospective clinical surveillance of all culture and/or PCR-confirmed IPD in children <15 years was performed in all hospitals in the Island of Majorca (approximately 900,000 inhabitants) from January 2008 to December 2010. Incidence rate (IR) was calculated as cases/100,000 inhabitants using children population data.

RESULTS

66 IPDs were identified: 39 (59.1%) parapneumonic pneumococcal empyema (PPE), 16 (24.2%) bacteremic pneumonia (BP), 7 (10.6%) primary bacteremia, 3 (4.5%) meningitis, and 1 (1.5%) osteomyelitis. IRs in the three-year study period were: 64.22 for children 12- < 24 months, 37.21 for those 24-59 months, 22.62 for those <12 months, and 3.98 for children >59 months. By study year, IRs were 21.25 in 2008, 19.89 in 2009 and 9.80 in 2010. The reduction found in 2010 was significant and due to significant reductions in IRs of IPDs caused by serotypes included in PCV10 and PCV13. Overall, estimated serotype coverage by conjugate vaccines was 12.1% for PCV7, 37.9% for PCV10 and 65.2% for PCV13. Of the 66 hospitalized children with IPD, 20 had received at least one dose of PCV7 (13 cases with identified serotype). None of these 13 cases was caused by PCV7 serotypes, all were caused by PCV13 serotypes and only 53.8% by PCV10 serotypes.

CONCLUSIONS

The results of the present study evidence the importance of expanding the number of serotypes covered by PCV, and the added value of PCV13 with respect to PCV10 and PCV7, even in an area of low prevalence of 19A as the Island of Majorca.

Serotype 5 pneumococci causing invasive pneumococcal disease outbreaks in Barcelona, Spain (1997 to 2011)

In this study, we analyzed the clinical and molecular epidemiology of invasive serotype 5 (Ser5) pneumococcal isolates in four teaching hospitals in the Barcelona, Spain, area (from 1997 to 2011). Among 5,093 invasive pneumococcal isolates collected, 134 (2.6%) Ser5 isolates were detected. Although the overall incidence of Ser5-related invasive pneumococcal disease (IPD) was low (0.25 cases/100,000 inhabitants), three incidence peaks were detected: 0.63/100,000 in 1999, 1.15/100,000 in 2005, and 0.37/100,000 in 2009. The rates of Ser5 IPD were higher among young adults (18 to 64 years old) and older adults (>64 years old) in the first two peaks, whereas they were higher among children in 2009. The majority (88.8%) of the patients presented with pneumonia. Comorbid conditions were present in young adults (47.6%) and older adults (78.7%), the most common comorbid conditions being chronic obstructive pulmonary disease (20.6% and 38.3%, respectively) and cardiovascular diseases (11.1% and 38.3%, respectively). The mortality rates were higher among older adults (8.5%). All Ser5 pneumococci tested were fully susceptible to penicillin, cefotaxime, erythromycin, and ciprofloxacin. The resistance rates were 48.5% for co-trimoxazole, 6.7% for chloramphenicol, and 6% for tetracycline. Two major related sequence types (STs), ST1223 (n = 65) and ST289 (n = 61), were detected. The Colombia(5)-ST289 clone was responsible for all the cases in the Ser5 outbreak in 1999, whereas the ST1223 clone accounted for 73.8% and 61.5% of the isolates in 2005 and 2009, respectively. Ser5 pneumococci are a frequent cause of IPD outbreaks in the community and involve children and adults with or without comorbidities. The implementation of the new pneumococcal conjugated vaccines (PCV10 and PCV13) might prevent such outbreaks.

Expansion of serotype coverage in the universal pediatric vaccination calendar: short-term effects on age- and serotype-dependent incidence of invasive pneumococcal clinical presentations in Madrid, Spain

In Madrid, Spain, the 13-valent pneumococcal conjugate vaccine (PCV13) replaced PCV7 in the pediatric universal vaccination calendar in June 2010. A prospective clinical surveillance that included all children hospitalized with culture- and/or PCR-confirmed invasive pneumococcal disease (IPD) was performed in all Madrid hospitals. The incidence rates (IRs) (defined as the number of cases/100,000 inhabitants aged <15 years) in the PCV7 (May 2007 to April 2010) versus PCV13 (May 2011 to April 2012) periods were compared. There were 499 cases in the PCV7 period and 79 cases in the PCV13 period. Globally, the IR significantly decreased from 17.09 (PCV7 period) to 7.70 (PCV13 period), with significant decreases (PCV7 versus PCV13 periods) in all age groups for bacteremic pneumonia (5.51 versus 1.56), parapneumonic pneumococcal empyema (PPE) (5.72 versus 3.12), and meningitis (2.16 versus 0.97). In the PCV13 period, significant reductions (the IR in the PCV7 period versus the IR in the PCV13 period) were found in IPDs caused by PCV13 serotypes (13.49 versus 4.38), and specifically by serotypes 1 (globally [4.79 versus 2.53], for bacteremic pneumonia [2.23 versus 0.97], and for PPE [2.26 versus 1.17]), serotype 5 (globally [1.88 versus 0.00], for bacteremic pneumonia [0.89 versus 0.00], and for PPE [0.55 versus 0.00]), and serotype 19A (globally [3.77 versus 0.49], for bacteremic pneumonia [0.72 versus 0.00], for PPE [0.89 versus 0.00], and for meningitis [0.62 versus 0.00]). IPDs caused by non-PCV13 serotypes did not increase (IR, 3.60 in the PCV7 period versus 3.31 in the PCV13 period), regardless of age or presentation. No IPDs caused by the PCV13 serotypes were found in children who received 3 doses of PCV13. The number of hospitalization days and sanitary costs were significantly lower in the PCV13 period. The switch from PCV7 to PCV13 in the universal pediatric vaccination calendar provided sanitary and economical benefits without a replacement by non-PCV13 serotypes.

[Emergence of invasive pneumococcal disease caused by non-vaccine serotypes in the era of the 7-valent conjugate vaccine]

INTRODUCTION

There has been an increased incidence in invasive pneumococcal disease (IPD) produced by non-vaccine serotype (NVS) of Streptococcus pneumoniae after the introduction of PCV7. Our objective was to describe the epidemiological, clinical and microbiological characteristics of IPD caused by NVS in a tertiary hospital in Madrid.

PATIENTS AND METHODS

Retrospective (1998-2004) and prospective (2005-2009) study evaluating IPD caused by NVS in children. The study was divided into three periods: P1 (1998-2001) when PCV7 was not commercialized; P2 (2002-2005) with 40% vaccine coverage among children; and P3 (2006-2009) when the vaccine was added to the Childhood Immunization Schedule in Madrid.

RESULTS

We analyzed 155 cases of IPD. One hundred and fifty of these isolates were serotyped (100 were NVS). There was an increase in the prevalence of IPD from P1 (31%) to P2 (54%) and P3 (91%). The most relevant emerging serotypes were 19A, 7F, 1, 5, 3 and 15C. The most significant clinical syndromes produced by some specific serotypes were as follows: lower respiratory tract infection (LRTI) by serotypes 1, 3, 5 and 15C; LRTI, primary bacteremia and meningitis by serotype 19A; and primary bacteremia by serotype 7F (66%). The large majority (83.8%) of NVS were sensitive to penicillin.

CONCLUSIONS

There has been an increased prevalence of IPD caused by NVS since the introduction of PCV7. These changes should prompt the introduction of new pneumococcal vaccines, which include most of the NVS, in the childhood immunization calendar to prevent IPD in children.

Impact of introduction of conjugate vaccines in the vaccination schedule on the incidence of pediatric invasive pneumococcal disease requiring hospitalization in Madrid 2007 to 2011

BACKGROUND

Differences in invasive pneumococcal disease (IPD) in children are expected after a change from 7-valent pneumococcal conjugate vaccine (PCV7) to 13-valent pneumococcal conjugate vaccine (PCV13). Universal vaccination with PCV7 started in Madrid in November 2006, and it switched to PCV13 in June 2010.

METHODS

A prospective, laboratory-confirmed (by culture or polymerase chain reaction), clinical surveillance including all pediatric IPD requiring hospitalization in Madrid was performed in all hospitals with a pediatric department and included four 1-year periods from May 2007 to April 2011. Incidence rate (IR) was calculated as number cases per 100,000 inhabitants using children population data.

RESULTS

Six hundred fourteen IPDs were identified: 209 parapneumonic pneumococcal empyema, 191 bacteremic pneumonia, 75 primary bacteremia, 72 meningitis, 38 IPDs secondary to otic foci and 29 others. The incidence of IPD remained unchanged during 2007-2010 (IR=≈17.0), with a marked decrease in 2010-2011 (IR=11.34; P<0.05) attributable to reduction in children younger than 24 months (50.19 in 2008-2009 compared with 24.92 in 2010-2011; P<0.005). The incidence of bacteremic pneumonia (R²=0.966; β=1.132; P=0.017) and meningitis (R²=0.898; β=0.505; P=0.052) showed decreasing linear trends over time. The incidence of parapneumonic pneumococcal empyema increased in 2009-2010 but decreased in 2010-2011 (6.73 vs. 4.14; P=0.019). The incidence of IPDs by PCV13 serotypes was significantly (P≤0.004) lower in 2010-2011 (8.78) than in previous periods (IR=≈13.5).

CONCLUSIONS

Early data regarding changing from PCV7 to PCV13 use in the childhood vaccination calendar indicate that reductions in IR of bacteremic pneumonia and meningitis after PCV7 introduction (by reduction of cases by serotypes 1 and 19A) further decreased and there was a reversion of the increase in IR of parapneumonic pneumococcal empyema from 2010-2011, mainly because of reduction in serotype 1 and 19A cases.

Serotypeº1 [corrected] childhood invasive pneumococcal disease has unique characteristics compared to disease caused by other streptococcus pneumoniae serotypes

BACKGROUND

We aimed to determine whether serotype 1 (SP1) invasive pneumococcal disease (IPD) can be distinguished by demographic, clinical and laboratory characteristics from IPD caused by the other most common serotypes (MCS) in our region: 5, 14, 6A, 6B, 19A, 19F, 23F.

METHODS

Data for all IPD episodes in children <18 years old treated at the Soroka University Medical Center during 2000 to 2009 were retrospectively retrieved. Episodes caused by SP1-IPD were compared with those caused by MCS-IPD (both grouped and individual serotypes). Analyses were adjusted for age and ethnicity.

RESULTS

Ninety-four SP1-IPD and 250 MCS-IPD episodes were documented. SP1-IPD cases were older (68.3 ± 52.6 months versus 30.4 ± 39.2 months; P < 0.001) and more likely to be found in Bedouin children than MCS-IPD (87.5% versus 58.6%; P < 0.001). SP1 was less frequently isolated from patients with underlying disease than MCS (14.9% versus 31.6 %; P < 0.001; relative risk 0.15 [95% confidence interval: 0.07-0.32]). SP1 was more often associated with bacteremic pneumonia and primary peritonitis than MCS (66% versus 38.4% and 7.4% versus 0.8%, respectively; P < 0.001); the proportion of bacteremia without focus was higher in MCS-IPD (32.4% versus 12.5%; P < 0.001). There were no differences in hospitalization and mortality rates (70.2% versus 68.0% [P = 0.22] and 4.3% versus 5.6% [P = 0.26], respectively).

CONCLUSIONS

SP1 was found less frequently than MCS in children with underlying diseases, but it was more frequent in older and Bedouin children with IPD. SP1 was more frequently associated with bacteremic pneumonia and primary peritonitis than MCS grouped.

Benefit of conjugate pneumococcal vaccination in preventing influenza hospitalization in children: a case-control study

BACKGROUND

The pneumococcal conjugate vaccine (PCV) might prevent hospitalizations in children because of the role of Streptococcus pneumoniae in the complications of influenza infection. We investigated the benefit of PCV vaccination in preventing influenza hospitalization in children <5 years of age during the 2009 to 2010 pandemic wave and the 2010 to 2011 influenza epidemic in Spain.

METHODS

A multicenter matched case-control study was undertaken in 27 hospitals from 7 Spanish regions between July 2009 and April 2011. A case was defined as a hospitalized patient between 6 months and 5 years of age with influenza virus infection confirmed by real-time reverse-transcription polymerase chain reaction. We selected 2 matched controls for each case from patients with unplanned hospital admission for reasons other than acute respiratory infection or influenza-like illness. Cases and controls were matched according to age, date of hospitalization and province of residence. Crude and adjusted odds ratios were calculated for associations between influenza hospitalization and PCV vaccination.

RESULTS

One hundred ninety-four cases and 342 controls were included in the study. In the 2009 to 2010 pandemic wave, the adjusted benefit in preventing hospitalization was 48% (95% confidence interval: 1 to 76) in fully vaccinated children compared with -79% (95% confidence interval: -341 to 27) in the 2010 to 2011 influenza season.

CONCLUSIONS

The results obtained suggest that, in children <5 years of age, PCV vaccination reduced hospitalization during the 2009 to 2010 pandemic wave. By contrast, there was no observed benefit of vaccination in the 2010 to 2011 influenza season.

Pneumococcal sepsis and nasopharyngeal carriage

PURPOSE OF REVIEW

Streptococcus pneumoniae (the pneumococcus) remains an important cause of invasive disease including bacteraemia. This review highlights recent findings related to pneumococcal bacteraemia, virulence factors, and multiple colonization, including strain competition, biofilm formation, and competence.

RECENT FINDINGS

Countries with no vaccination programmes see vaccine serotypes still prevalent in disease, whereas the emergence of nonvaccine serotypes in nasopharyngeal carriage and invasive disease is seen in countries with conjugate vaccination in place. Co-colonizing strains are being uncovered with more sensitive methods, and may act synergistically or compete with each other for survival. Several factors such as iron uptake, quorum signalling and the luxS gene, involved in colonization and virulence, are discussed. The role of quorum sensing signalling molecules and formation of biofilms are being explored.

SUMMARY

Epidemiological data suggest that the latest serotype-based conjugate vaccines should provide heightened protection, although serotype replacement is now being seen. Much remains to be elucidated about its biology during multiple colonization, when evolution and adaptation to its host take place. The modes of colonization (biofilm, intracellular or surface adherence to the mucosal epithelium), and whether organisms that cause invasive disease have attenuated ability to colonize the nasopharynx remain to be elucidated.

Routine pneumococcal vaccination of children provokes new patterns of serotypes causing invasive pneumococcal disease in adults and children

INTRODUCTION

Routine vaccination of infants with protein-conjugated 7-valent pneumococcal vaccine (PCV7) begun in 2000 initiated a sea change of prevalent serotypes (STs) in invasive pneumococcal disease (IPD). The authors investigated in 1 community all STs causing IPD during 5 years before (PRE) and 2, 5-year periods after (POST1 and POST2) its initiation and found that PCV7 adversely affected ST coverage of 23-valent pneumococcal polysaccharide vaccine (PPV23) among adults.

METHODS

From 1996-2010, 620 consecutive Streptococcus pneumoniae IPD strains from adults (521) and children (99) hospitalized with IPD in Huntington, WV, were collected. Each strain was typed by Quellung reaction. The Marshall University Institutional Review Board approved this study.

RESULTS

By 6 to 10 years after the initiation of PCV7, IPD in children decreased significantly, whereas IPD in adults increased significantly. In both adults and children, IPD due to PCV7 STs decreased significantly. In adults with IPD, PCV7 STs were replaced by several non-PCV7 STs including STs contained in PPV23 but not in PCV7 and STs not contained in either vaccine. IPD due to 4 nonsusceptible STs included in PCV7 decreased from PRE to POST1 and POST2. IPD due to nonsusceptible STs not included in PCV7 increased from PRE to POST1 and POST2.

CONCLUSIONS

Routine PCV7 decreased IPD in children but not in adults. Predominant STs changed--children exhibited fewer PCV7 STs and adults exhibited fewer PCV7 and PPV23 STs--reducing vaccine coverage and increasing the risk of replacement STs causing IPD in adults.

Epidemiology of vaccine-preventable invasive diseases in Catalonia in the era of conjugate vaccines

We investigated the incidence and distribution of cases of invasive pneumococcal disease (IPD), invasive meningococcal disease (IMD) and invasive Hemophilus influenzae disease (IHiD) notified by hospital laboratories to the Microbiological Reporting System of Catalonia between 2005 and 2009. Incidence rates were compared using the rate ratio (RR) and 95% CI were calculated. A value of p < 0.05 was considered statistically significant. Of the 6,661 cases, 6,012 were IPD, 436 IMD and 213 IHiD. The global annual incidence per 10 ( 5) inhabitants was 16.62 (95% CI 16.20-17.04) for IPD, 1.21 (95% CI 1.09-1.32) for IMD and 0.59 (95% CI 0.51-0.67) for IHiD. IPD increased in 2009 compared with 2005 (RR:1.55, 95%CI: 1.43-1.70) and IMD and IHiD remained stable. Pneumonia was the most-frequent clinical manifestation of IPD (75.6%) and IHiD (44.1%) and meningoencephalitis with or without sepsis for IMD (70.6%). The male:female ratio was 1.37 for IPD, 1.0 for IMD and 1.15 for IHiD. The age groups with the highest incidence were the ≤ 2 y and 2-4 y groups for IPD (66.40 and 50.66/100,000 persons-year) and IMD (14.88 and 7.26/100,000 persons-year) and the ≤ 2 y and ≥ 65 y groups for IHiD (1.88 and 1.89/100,000 persons-year). The most-frequent serotypes were serotype 1 (19.0%) in IPD and untypeable serotypes (60.8%) in IHiD. Serogroup B (78.3%) was the most frequent in IMD. S. pneumoniae is the most-frequent agent causing invasive disease in Catalonia. The main clinical manifestations were pneumonia in IPD and IHiD and meningitis in IMD. The main causative agent of meningitis was N. meningitidis in people aged < 20 y and S. pneumoniae in people aged ≥ 20 y. Vaccination with conjugate vaccines may reduce the risk of infectious disease in our setting.

Are risk factors associated with invasive pneumococcal disease according to different serotypes?

The aim of this study was to investigate risk factors for the most common serotypes of invasive pneumococcal disease (IPD). A total of 293 IPD cases were analyzed in children aged 3-59 mo in a community with intermediate vaccination coverage with the 7-valent pneumococcal vaccine (PCV7). IPD cases were reviewed during 2007-2009 in two pediatric hospitals in Catalonia (Spain). A multivariate analysis using unconditional logistic regression was performed to estimate the adjusted odds ratio. PCV7 coverage was 45.4%. Pneumonia with empyema (64.5%) was the most frequent clinical manifestation. The most common serotypes were: serotype 1 (21.2%), 19A (16.0%), 3 (12.6%) and 7F/A (6.8%). 70.0% of serotypes found were included in the 13-valent conjugate vaccine (PCV13), 39.2% in the 10-valent conjugate vaccine and 8.1% in the PCV7. PCV7 was protective in IPD cases due to PCV7-serotypes (aOR: 0.15, 95% CI:0.04-0.55). Serotype 1 was positively associated with attending day care or school (aOR: 3.55, 95% CI: 1.21-10.38) and age 24-59 mo (aOR: 7.70, 95% CI:2.70-21.98). Serotype 19A was positively associated with respiratory infection in the previous month (aOR: 2.26, 95% CI: 1.03-4.94), non-penicillin susceptible IPD (aOR: 1.89, 95% CI:1.13-3.16) and negatively associated with age 24-59 mo (aOR: 0.19, 95% CI:0.09-0.41). Serotype 3 was positively associated with vaccination (aOR: 4.87, 95% CI:2.05-11.59). No factors were associated with serotype 7F/A. Vaccination with pneumococcal vaccines including more serotypes may reduce the risk of disease in our setting.

Clinical presentation of invasive pneumococcal disease in Spain in the era of heptavalent conjugate vaccine

BACKGROUND

The aim of this study was to analyze the rate of incidence, clinical presentation, serotype, and clonal distribution of invasive pneumococcal disease (IPD) in the era of heptavalent pneumococcal conjugate vaccine (PCV7) in Barcelona, Spain.

METHODS

This was a prospective study comprising all children <5 years with IPD who were managed in 2 tertiary-care, pediatric hospitals between January 2007 and December 2009. IPD was defined as the presence of clinical findings of infection together with isolation or detection of DNA of Streptococcus pneumoniae in a sterile fluid sample.

RESULTS

In this study, 319 patients (53.3% male), mean age 29.6 months, were included. Comparing rates in 2007 and 2009 (76.2 and 109.9 episodes/100,000 population, respectively), an increase of 44% (95% confidence interval, 10%-89%) was observed. The main clinical presentation was pneumonia (254 episodes, 79.6%), followed by meningitis (29, 9.1%), and bacteremia (25, 7.8%).The diagnosis was made by positive culture in 123 (38.6%) patients and in 196 (61.4%) by real-time polymerase chain reaction. Serotype study was performed in 300 episodes, and 273 (91%) were non-PCV7 serotypes. The most frequent serotypes were 1 (20.7%), 19A (15.7%), and 3 (12.3%). A minimal inhibitory concentration ≥0.12 μg/mL to penicillin was detected in 34.4% of isolates. Sequence type 306 expressing serotype 1 was the most frequent clonal type detected (20.3% of studied strains).

CONCLUSIONS

IPD continues to increase in Barcelona, and the rate is higher than previously reported as a result of low sensitivity of bacterial culture. Non-PCV7 serotypes were responsible for 91% of episodes and pneumonia was the main clinical presentation.

In vitro activity of ceftobiprole and seven other antimicrobial agents against invasive Streptococcus pneumoniae isolates in Spain

The in vitro activity of ceftobiprole was compared with that of seven antimicrobial agents against invasive Streptococcus pneumoniae isolated from adult patients (>15 years old). Characterization of erythromycin-resistant strains and serotype distribution of all pneumococci were also evaluated. Seventy invasive S. pneumoniae strains were isolated from December 2007 to January 2009. Serotyping was carried out by Quellung reaction. Antibiotic susceptibility was tested by broth microdilution (CLSI guidelines). The comparator agents were penicillin, cefotaxime, erythromycin, clindamycin, telithromycin, tetracycline and moxifloxacin. Phenotypic characterization of macrolide resistance was performed by the double disk method. Macrolide resistance genes [erm(B) and mef(A/E)] and the promoter of erm(B) were detected by PCR. Twenty-five different serotypes were detected of which 87% were non-PCV7 types. The percentages of resistance to erythromycin, clindamycin and tetracycline were 20%, 8.6% and 16%, respectively. A penicillin MIC ≥0.12 mg/L was observed in 14 of the 70 invasive pneumococci strains. The cefotaxime and ceftobiprole MIC(50)/MIC(90) of these 14 strains were 1/4 and 0.03/1 mg/L, respectively. Ceftobiprole showed higher in vitro activity than penicillin and cefotaxime with all isolates being inhibited by ≤1 mg/L. Its high in vitro activity should make ceftobiprole a very promising drug for the treatment of pneumococcal infections.

Invasive pneumococcal disease: association between serotype, clinical presentation and lethality

To ascertain the factors linked to invasive pneumococcal disease (IPD) caused by the different serotypes in the period 2007-2009, following the conjugate vaccine's inclusion in the childhood vaccination schedule, a total of 2013 IPD cases were reviewed. The mean annual incidence in this period was 10.74 cases per 100,000 inhabitans and the lethality was 8.8%. Overall serotype distribution displayed certain peculiarities, such as the high frequency of serotype 5. Serotype 3, male gender, sepsis and presence of risk factors were significantly associated with lethality. Vaccinated children under 5 years of age had a higher risk of disease due to serotype 19A. Serotype 8 was associated with the presence of underlying risk factors.

Cefditoren in upper and lower community-acquired respiratory tract infections

This article reviews and updates published data on cefditoren in the evolving scenario of resistance among the most prevalent isolates from respiratory tract infections in the community (Streptococcus pyogenes, Haemophilus influenzae, and Streptococcus pneumoniae). By relating the in vitro activity of cefditoren (in national and multinational surveillance and against isolates with emerging resistant genotypes/phenotypes) to its pharmacokinetics, the cefditoren pharmacodynamic activity predicting efficacy (in humans, animal models, and in vitro simulations) is analyzed prior to reviewing clinical studies (tonsillopharyngitis, sinusitis, acute exacerbations of chronic bronchitis, and community-acquired pneumonia) and the relationship between bacterial eradication and clinical efficacy. The high in vitro activity of cefditoren against the most prevalent respiratory isolates in the community, together with its pharmacokinetics (enabling a twice daily regimen) leading to adequate pharmacodynamic indexes covering all S. pyogenes, H. influenzae, and at least 95% S. pneumoniae isolates, makes cefditoren an antibiotic that will play a significant role in the treatment of respiratory tract infections in the community. In the clinical setting, studies carried out with cefditoren showed that treatments with the 400 mg twice daily regimen were associated with high rates of bacteriological response, even against penicillin-nonsusceptible S. pneumoniae, with good correlation between bacteriological efficacy/response and clinical outcome.