Pneumococcal serotype distribution and antimicrobial resistance in Chinese children hospitalized for pneumonia

A prospective study was performed to determine serotype distribution and antimicrobial resistance in Streptococcus pneumoniae (S. pneumoniae) from Chinese children <5 years old meeting pneumonia criteria. A total of 3865 children were enrolled and 338 S. pneumoniae isolates were obtained. The most frequent serotypes were 19F (55.6%), 19A (13.9%), 23F (10.1%), 6B (4.7%), and 14 (3.6%). The 7-, 10- and 13-valent conjugate vaccines, respectively, covered 76.3%, 76.9%, and 92.3% of isolates. Out of the isolates, six (1.8%) were penicillin resistant. All except 1 of the isolates were resistant to erythromycin. Serotype 19A showed the highest drug resistance. The use of PCV7 has the potential to prevent a substantial number of pneumococcal infections. However, PCV13 is likely to prevent more episodes of pneumococcal disease in China because of the high rates of 19A.     

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.     

Distribution, dynamics and antibiotic resistance patterns of Streptococcus pneumoniae serotypes causing acute otitis media in children in southern Israel during the 10 year-period before the introduction of the 7-valent pneumococcal conjugate vaccine

Objectives

To determine the dynamics of serotype prevalence, potential coverage by pneumococcal conjugate vaccines (PCV) and antibiotic resistance patterns of Streptococcus pneumoniae causing acute otitis media (AOM) in children in southern Israel before PCV7 introduction in the routine immunization program in Israel.

Methods

All S. pneumoniae isolates from middle ear fluid from children with AOM during 1999-2008 were included. Prospectively collected demographic data on S. pneumoniae serotypes and antibiotic resistance patterns were analyzed.

Results

A total of 14,911 tympanocenteses yielded 5281(35%) S. pneumoniae. Proportion of S. pneumoniae-AOM did not vary significantly (overall 35%; 33% in 2007; 38% in 2002 and 2003). The most frequent serotypes were 19F, 14, 23F and 19A; in both Jewish and Bedouin children; serotypes 6A and 19A contributed 6% and 10%, respectively, of all S. pneumoniae isolates. Serotypes included in PCV7, PCV10 and PCV13 represented 60%, 64%, 85% in Jewish children vs. 49%, 55% and 74%, respectively, in Bedouin children (P < 0.001). Nonsusceptibility to TMP/SMX decreased significantly, in parallel with a significant increase in the nonsusceptibility to erythromycin, clindamycin and in multidrug resistant (MDR) isolates. No changes were recorded in the proportion of S. pneumoniae isolates with penicillin MIC ≥ 1.0 μg/ml. The proportion of penicillin- and erythromycin-nonsusceptible and of MDR serotype 6A and 19A isolates increased significantly in Bedouin children.

Conclusions

1) No significant changes were recorded in the yearly proportions of serotypes 23F, 19F, 19A, 14 and 6A in both ethnic populations; 2) Potential coverage of the 3 PCVs was higher in Jewish children than in Bedouin children; 3) The relatively high coverage of macrolides- and multidrug-resistant S. pneumoniae by PCV13 and lack of increase in penicillin, erythromycin and multidrug nonsusceptibility among non-PCV13 isolates is encouraging.     

Changes in Streptococcus pneumoniae serotype distribution in invasive disease and nasopharyngeal carriage after the heptavalent pneumococcal conjugate vaccine introduction in Bogotá, Colombia

Background

In Bogotá, the Heptavalent Conjugate Vaccine (PCV7) was introduced into childhood immunization schedule since 2009. The aim of this study was to assess the changes in serotype distribution and penicillin susceptibility of Streptococcus pneumoniae isolates recovered from nasopharyngeal samples and invasive disease among children living in Bogotá, before and after PCV7 introduction.

Methods

Nasopharyngeal swabs were collected from healthy children aged between 12 and 18 months of age before (years 2005–2006) and after (2011) PCV7 introduction. Identification of S. pneumoniae was performed by multiplex PCR. Serotype was determined by PCR and Quellung reaction. Susceptibility to penicillin, ceftriaxone, trimethoprim-sulfamethoxazole, chloramphenicol, tetracycline and erythromycin was evaluated. In addition, distribution of serotypes and antimicrobial susceptibility before and after vaccine introduction among invasive isolates recovered from children ≤2 years old living in Bogotá was analyzed.

Results

Prevalence of pneumococcal nasopharyngeal carriage declined from 55.7% (137/246) in unvaccinated to 44.2% (87/197) (p = 0.01) in vaccinated children. The proportion of children carrying PCV7 serotypes decreased from 23.6% (58/246) to 7.6% (15/197) (p < 0.001). The decrease was counterbalanced by an increase in the proportion of non-PCV7 serotypes. The most prevalent among emerging serotypes were 15A, 15B, 15 C, 11A and 35B. Among IPD isolates, PCV7 serotypes decreased from 69.1% (235/340) in 2005/2009 to 38.0% (32/84) in 2010/2011 (p < 0.001). The increase of non-PCV7 serotypes was significant. Resistance to penicillin among invasive isolates recovered from meningitis decreased from 41.1% (30/73) in the pre-vaccine period to 14.2% (2/14) in post-vaccine period (p = 0.02).

Conclusions

A decrease in the prevalence of pneumococcal nasopharyngeal carriage following the introduction of PCV7 vaccine, have been overshadowed by an important surge in the prevalence of non-PCV7 serotypes. Systematic surveillance combining nasopharyngeal carriage surveys and IPD detection could help in evaluating the impact of conjugate vaccines.     

Phenotype,genotype, and serotype distribution of macrolide resistant invasive and non-invasive Streptococcus pneumoniae strains,in Sousse,Tunisia

ObjectiveWe determined the macrolide resistance phenotypes and genotypes in Streptococcus pneumoniae isolates in Sousse and assessed the serotype distribution.MethodsWe included S. pneumoniae strains isolated at our laboratory (2010–2013). The antimicrobial susceptibility was tested according to CA-SFM specifications. Serotyping was performed by agglutination of latex particles, to identify a subset of serotypes included in pneumococcal conjugate vaccines. The presence of macrolide resistance genes (ermB, mefA, mel) was detected by PCR.ResultsA total of 52.8% of 140 S. pneumoniae isolates were macrolide-resistant: MLSB (89.2%) and M (10.8%). The MLSB phenotypes were genotypically confirmed by ermB gene presence. 62% had decreased susceptibility to penicillin. The serotypes were: 14, 1, 23F, and 19A. Serotype coverage by PCV7, PCV10 and PCV13 was 44.2%, 73.6%, and 75.6% respectively.Conclusion50% of S. pneumoniae isolates were macrolide resistant. The MLSB phenotype encoded by the ermB gene was the most frequent. Serotype coverage seems inadequate.     

Nasopharyngeal carriage of Streptococcus pneumoniae in Taiwan before and after the introduction of a conjugate vaccine

Background

The heptavalent pneumococcal conjugate vaccine was introduced in Taiwan in October 2005. To evaluate the effect of the vaccination, we conducted an active, prospective, large-scale, long-term, and multicenter study to assess the prevalence of nasopharyngeal Streptococcus pneumoniae carriage in Taiwanese children.

Methods

This study was performed at three tertiary teaching hospitals in northern, central, and southern Taiwan. Questionnaires provided demographic, family/household, and medical history data. Pneumococcal isolates were tested for their susceptibility to various antimicrobial agents and serotypes. In addition, influenza virus and Staphylococcus aureus were recovered from nasopharyngeal and nasal swabs, respectively.

Results

Between July 2005 and July 2008, 857 pneumococcal strains were recovered from a total of 6057 children aged >2 months to 5 years (carriage rate, 14.1%). Carriage rates differed geographically and varied with subject age. In a multivariate analysis, having at least one sibling, attendance at day-care centers, a history of otitis media, and history of upper respiratory tract infection in the previous 2 weeks were each associated with a higher risk of pneumococcal colonization of the nasopharynx. Staphylococcus aureus nasal colonization was inversely associated with nasopharyngeal carriage of pneumococcus (p = 0.000; odds ratio [OR]: 0.48; 95% CI: 0.39-0.58). Daycare attendance was the only risk factor for carriage of penicillin non-susceptible S. pneumoniae (OR: 2.37; 95% CI: 1.22-4.88). Although vaccination rates rose from 2005 to 2008, no concomitant decrease in S. pneumoniae carriage occurred. The rate of penicillin resistance among S. pneumoniae isolates was 92.8% (using the meningitis criteria). The prevalence of cefotaxime resistance (21.6%) was higher than that of penicillin (6.9%; non-meningitis criteria). Slightly more than half (57.4%) of the isolates belonged to strains covered by the heptavalent pneumococcal conjugate vaccine when both vaccine and vaccine-related serotypes were included.

Conclusions

Although vaccination rates rose from 2005 to 2008, no concomitant decrease occurred in S. pneumoniae carriage. Interaction between S. aureus and S. pneumoniae may influence vaccination efficacy. These findings provide baseline data to further compare pneumococcal carriage rates and antibiotic resistance patterns in Taiwanese children as vaccination rates continue to increase.     

Serotypes and antimicrobial susceptibilities of invasive Streptococcus pneumoniae pre- and post-seven valent pneumococcal conjugate vaccine introduction in Alberta,Canada, 2000–2006

Alberta, Canada introduced the Streptococcus pneumoniae seven valent conjugate vaccine (PCV7) program for children less than 2 years of age in September 2002. We determined the rates of invasive pneumococcal disease in Alberta, Canada 2 years pre- and 4 years post-PCV7 introduction (2000–2006) as well as the rates of antibiotic resistance and serotype distribution in this same time period. Overall, PCV7 serotypes decreased 61% from 2000 to 2006. The greatest decrease in incidence of invasive pneumococcal disease occurred in children less than 2 years of age declining from a high of 96.7/100,000 (2000) to 25.8/100,000 (2006) (P < 0.0001). Non-susceptibility of S. pneumoniae isolates to penicillin dropped significantly from 14% in 2000 to 4.6% in 2006 (P < 0.0001). Non-susceptible erythromycin isolates also decreased from 8.8% (2000) to 5.8% (2006) (P = 0.13).     

Serotype coverage of pneumococcal conjugate vaccine and drug susceptibility of Streptococcus pneumoniae isolated from invasive or non-invasive diseases in central Thailand, 2006–2009

The serotype of 172 S. pneumoniae isolates obtained from normally sterile sites from January 2006 to February 2009 in Thai patients was evaluated. The most common serotypes were 6B, 23F, 14, 19F, and 19A in patients <5 year-old, and 6B, 19A, 23F, 4, 9V in patients >65-year old. Seven-valent pneumococcal conjugated vaccine (PCV-7) covered 70.3%, 43.6%, and 43.5% of patients <5, 5–64 and ≥65 years of age, respectively, while PCV-13 covered 81.2%, 59.7%, and 60.9%, respectively. PCV-9, PCV-10, PCV-11 had very similar coverage as PCV-7. The antibiotic susceptibility rates of the isolates from sterile sites were 88.7–95.7% for penicillin, 90.6–98.4% for cefotaxime, 92.2–100% for ofloxacin and 100% for ciprofloxacin. PCV-7 covered 83% and 100%, respectively, of penicillin and cefotaxime non-susceptible isolates in patients <5-year old.     

Bacterial etiology and serotypes of acute otitis media in Mexican children

Streptococcus pneumoniae and Haemophilus influenzae have been consistently reported to be the two major bacterial pathogens responsible for acute otitis media (AOM), mainly from studies in the US and Europe. However, data on bacterial pathogens causing AOM in Latin America are limited. Understanding the relative importance of these pathogens in a specific setting, the serotype distribution, and their antibiotic susceptibility levels is important to provide local vaccine and treatment recommendations. We therefore conducted a prospective, multi-center, tympanocentesis-based epidemiological study of Mexican children three months to less than five years of age. Fifty percent of episodes were in children who had received at least one dose of PCV7. Overall, 64% of samples were culture positive for bacterial pathogens. H. influenzae and S. pneumoniae were the leading causes of bacterial AOM, detected in 34% and 29% of AOM episodes, respectively. The most commonly isolated S. pneumoniae serotypes were 19A, 19F and 23F. All H. influenzae isolates were identified as non-typeable. Seventy-four percent of S. pneumoniae were susceptible to penicillin, while 97% were susceptible to amoxicillin/clavulanate. All H. influenzae samples were susceptible to amoxicillin/clavulanate and cefotaxime, 95% to cefuroxime and 75% to ampicillin. Both S. pneumoniae and non-typable H. influenzae represent important targets for vaccination strategies to reduce AOM in Mexican children.     

Molecular epidemiology and genetic diversity of pneumococcal carriage among children in Beni State, Bolivia

During 2007, a study of pneumococcal carriage in children was performed in two towns (Trinidad and Riberalta) in the Beni region of the Bolivian Amazon basin. Little has previously been reported regarding the epidemiology of pneumococcal carriage in Bolivia, and no multilocus sequence typing (MLST) of pneumococcal isolates from this region has previously been documented. A pneumococcal carriage rate of 34% was identified. Of 53 Streptococcus pneumoniae isolates that survived transportation for serotyping, antibiotic susceptibility testing and MLST, the commonest serotypes were 6A (9%), 34 (8%), 4 (6%), 9A (6%), 10A (6%), 19A (6%), 23F (6%) and 38 (6%); overall, 26 different serotypes were identified. Antibiotic susceptibility testing by Etest demonstrated high levels of susceptibility to penicillin (93%), erythromycin (98%), vancomycin (100%), chloramphenicol (100%), tetracycline (96%) and trimethoprim/sulfamethoxazole (co-trimoxazole) (85%). MLST identified that the majority (57%) of viable isolates belonged to previously unrecognised sequence types that are currently unique to Bolivia.     

Pneumococcal disease caused by serotype 19A: Review of the literature and implications for future vaccine development

Streptococcus pneumoniae serotype 19A is associated with all forms of pneumococcal disease and was the first reported pneumococcal serotype with high-level penicillin and multidrug resistance. While the seven-valent pneumococcal conjugate vaccine (PCV7), which contains serotype 19F, has reduced rates of disease among children and adults, the incidence of disease due to nonvaccine and increasingly drug-resistant serotypes – predominantly serotype 19A – has increased. This review summarizes the published literature to analyze the factors contributing to the emergence of serotype 19A, the diseases associated with this serotype, and the importance of including this serotype in novel pneumococcal conjugate vaccines. A recently approved 13-valent vaccine includes this serotype, and is likely to significantly reduce the burden of disease due to serotype 19A.     

The current status of invasive pneumococcal disease in Poland

The objectives of this study were to assess the incidence of invasive pneumococcal disease (IPD) in Poland (2006-2009), where mass vaccination had not been implemented, and to determine the serotype distribution and antimicrobial susceptibility of Streptococcus pneumoniae isolates. The IPD incidence rates were highest among children under 2 years of age (3.39/100,000 in 2009) and children 2-5 years old (2.44/100,000). The most common serotypes were 14, 3, 1, 4, 19F, 23F, 6B, and 12F (61.7% of all isolates). In children aged less than 5 years, isolates of serotypes 14, 6B, and 19F were most prevalent (52.7% of the IPD cases). The PCV7, PCV10, and PCV13 covered 43.3%, 54.8%, and 68.8% of all IPD cases, and 68.7%, 76.3%, and 86.3% of cases involving children under 5 years of age. Penicillin resistance was found in 21.3% of the isolates responsible for meningitis and in 1.2% of isolates responsible for other invasive infections.Introduction of antipneumococcal conjugated vaccines into the national immunisation programme would likely lead to a significant reduction of IPD-associated morbidity among Polish children in particular, as well as in the population as a whole, especially in cases involving pneumococci with a decreased susceptibility to antibiotics.     

The changing phenotypes and genotypes of invasive pneumococcal isolates from children in Shenzhen during 2013–2017

BackgroundThe phenotypes and genotypes of Streptococcus pneumoniae isolated from invasive pneumococcal diseases (IPDs) were changing all the time. To monitor these changes of phenotypes and genotypes of S. pneumoniae isolates from children, we examined antibiotic susceptibility, serotype distribution and sequence types (STs) of S. pneumoniae, which were isolated before the 13-valent pneumococcal conjugate vaccine (PCV13) introduced into China.MethodsStrains were isolated from children less than 14 years old between January 2013 and May 2017 from Shenzhen Children’s Hospital. Serotypes, antibiotic resistance, and genotypes of these isolates were determined using capsular swelling, E-test, and multi-locus sequence typing, respectively.ResultsA total of 94 S. pneumoniae strains were isolated, which belonged to 15 serotypes. The five most prevalent serotypes were 19F (25.5%), 19A (19%), 14 (17%), 23F (7.5%), and 6B (9.6%). We found 42 STs for these isolates. The most abundant STs were ST271 (24.4%), ST876 (17%), and ST320 (10.6%), mainly related to 19F, 14, and 19A, respectively. The potential coverage of PCV13 was 87.2%. Among non-meningitis isolates, the resistance rates to penicillin and ceftriaxone were 0% and 2%. However, the meningitis isolates showed high resistance to penicillin (80%) and ceftriaxone (20%). Most of these isolates (95.7%) were resistant to erythromycin, and 66 (70.2%) strains carried the ermB gene and 24 (25.5%) strains carried both the ermB and mefA/E genes. Serotype 19A showed the highest mean minimum inhibitory concentration (MIC) for penicillin (MIC = 1.486) than the other serotypes, but no significant difference in penicillin MIC among the three main STs (ST271, ST320, and ST876).ConclusionsThe phenotypes and genotypes of invasive pneumococcal isolates from Shenzhen Children’s Hospital have changed with the passage of time. Compared with PCV7, PCV13 can more effectively protect Chinese children from IPDs. To some extent, these changes are possibly related to the usage of antibiotics and vaccines.     

Serotypes and antimicrobial susceptibilities of invasive Streptococcus pneumoniae before and after introduction of 7-valent pneumococcal conjugate vaccine, Hong Kong, 1995-2009

This study analyzed 828 isolates causing invasive pneumococcal disease (IPD) before (1995-2001, n = 265) and after (2007-2009, n = 563) the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in Hong Kong. In children <5 years, serotype 14 had declined (36-15.7%, P < 0.01) while 19A had increased (0-12.9%, P < 0.01) in the before and after periods, respectively. In children aged <5 years, the proportion of PCV7 serotypes declined from 89.5% to 65.7% (72.8% if included cross protection against 6A) with time but that of PCV13 serotypes remained stable (91.4-93.2%). In elderly ≥65 years, 9V and 23F decreased from 3.8% to 0.3% (P = 0.01) and from 18.9% to 7.4% (P <0.01), respectively while 7F increased significantly from 0% to 4.1% (P = 0.04) over the same periods. Among isolates from aged <5 years, dual penicillin/erythromycin resistance increased from 44.1% to 64.2% (P = 0.01). The types that often had dual penicillin/erythromycin resistance were 6B, 14, 19F, 23F, 6A and 19A. The emergence of serotype 19A was associated with expansion of sequence type 320.     

Serotypes 1, 7F and 19A became the leading causes of pediatric invasive pneumococcal infections in Portugal after 7 years of heptavalent conjugate vaccine use

We characterized 353 isolates responsible for pediatric invasive pneumococcal infections (IPD) in Portugal between 2006 and 2008. Serotypes included in the seven-valent conjugate vaccine (PCV7) accounted for 17% of IPD. Serotypes 1, 7F and 19A were the most frequent causes of IPD and the later consolidated as the most frequent serotype among erythromycin and penicillin non-susceptible isolates. Serotype 1 was associated with older children and empyemas, while serotype 19A was associated with IPD in younger (<2 years) children. The higher valency vaccines PCV10 and PCV13 have a potentially superior coverage, 55% and 83% respectively, but non-vaccine serotypes are emerging as important causes of IPD. A decline of resistance with patient age was noted. Comparing with previous data from Portugal, this study showed a continued decline of PCV7 serotypes and that overall resistance has stabilized following the initial decline of the first post-PCV7 years.     

Pneumococcal carriage,serotype distribution,and antimicrobial susceptibility in Papua New Guinean children vaccinated with PCV10 or PCV13 in a head-to-head trial

BackgroundChildren in Papua New Guinea (PNG) are at high risk of pneumococcal infections. We investigated pneumococcal carriage rates, serotype distribution, and antimicrobial susceptibility in PNG children after vaccination with 10-valent or 13-valent pneumococcal conjugate vaccines (PCV10; PCV13).MethodsInfants (N = 262) were randomized to receive 3 doses of PCV10 or PCV13 at 1-2-3 months of age, followed by pneumococcal polysaccharide vaccination (PPV) or no PPV at 9 months of age. Nasopharyngeal swabs (NPS) collected at ages 1, 4, 9, 10, 23 and 24 months were cultured using standard bacteriological procedures. Morphologically distinct Streptococcus pneumoniae colonies were serotyped by the Quellung reaction. Antimicrobial susceptibility was determined by Kirby-Bauer disc diffusion and minimum inhibitory concentration (MIC).ResultsS. pneumoniae was isolated from 883/1063 NPS collected at 1–23 months of age, including 820 serotypeable (64 different serotypes) and 144 non-serotypeable isolates. At age 23 months, 93.6% (95%CI 86.6–97.6%) of PCV10 recipients and 88.6% (95%CI 80.1–94.4%) of PCV13 recipients were pneumococcal carriers, with higher carriage of PCV10 serotypes by PCV10 recipients (19.8%, 95%CI 12.2–29.5) than PCV13 recipients (9.3%, 95%CI 4.1–17.3) (p = 0.049). There were no other statistically significant differences between PCV10 and PCV13 recipients and children receiving PPV or no PPV. Nearly half (45.6%) of carried pneumococci were non-susceptible to penicillin based on the meningitis breakpoint (MIC ≥ 0.12 µg/mL), but resistance was rare (1.1%) using the non-meningitis cut-off (MIC ≥ 8 µg/mL). Non-susceptibility to trimethoprim-sulfamethoxazole (SXT) was common: 23.2% of isolates showed intermediate resistance (MIC 1/19–2/38 µg/mL) and 16.9% full resistance (MIC ≥ 4/76 µg/mL). PCV serotypes 14 and 19A were commonly non-susceptible to both penicillin (14, 97%; 19A, 70%) and SXT (14, 97%; 19A, 87%).ConclusionEven after PCV10 or PCV13 vaccination, children living in a high-risk setting such as PNG continue to experience high levels of pneumococcal colonization, including carriage of highly antimicrobial-resistant PCV serotypes.The study is registered with ClinicalTrials.gov (CTN NCT01619462).     

Predominance of nontypeable Haemophilus influenzae in children with otitis media following introduction of a 3+0 pneumococcal conjugate vaccine schedule

In Australia the 7-valent pneumococcal conjugate vaccine (PCV7) is administered at 2, 4 and 6 months of age, with no booster dose. Information on bacterial carriage and the aetiology of recurrent acute otitis media (rAOM) after introduction of PCV7 using the 3 + 0 schedule is required to evaluate the potential impact of second generation pneumococcal vaccines. We found that 2-4 years after introduction of PCV7 in the National Immunisation Program, nontypeable Haemophilus influenzae (NTHi) was the predominant pathogen isolated from the nasopharynx and middle ear of children with a history of rAOM. Compared with healthy controls (n = 81), NTHi and Streptococcus pneumoniae carriage rates were significantly higher in children with a history of rAOM (n = 186) (19% vs. 56% p < 0.0001 and 26% vs. 41%, p = 0.02, respectively). Carriage of PCV7 pneumococcal serotypes was rare, whereas PCV7-related and non-PCV7 serotypes were isolated of 38% of cases and 24% of controls. Serotype 19A was the most common serotype isolated from the nasopharynx and middle ear and accounted for 36% (14/39) of total pneumococcal isolates with reduced susceptibility to cotrimoxazole. Of the 119 children carrying NTHi, 17% of isolates were β-lactamase positive.The scarcity of PCV7 serotypes in children with and without a history of rAOM indicates that the 3 + 0 PCV7 schedule is preventing carriage and rAOM from PCV7 serotypes. Introduction of new vaccines in Australia with increased pneumococcal serotype and pathogen coverage, including 19A and NTHi, should decrease the circulation of antibiotic-resistant bacteria and reduce the burden of rAOM.     

儿童侵袭性肺炎链球菌感染的血清型和耐药性

目的 了解某医院住院患儿侵袭性肺炎链球菌感染的临床特征以及菌株的血清型和耐药性,以期指导临床合理用药,寻找防治侵袭性肺炎链球菌感染的有效方法.方法 回顾性分析2014年1月—2018年12月该院明确诊断为侵袭性肺炎链球菌感染患儿的临床资料,肺炎链球菌的药敏结果、血清型,以及疫苗对其血清型覆盖情况.结果 74例侵袭性肺炎...     

Streptococcus pneumoniae serotypes isolated from the middle ear fluid of Costa Rican children following introduction of the heptavalent pneumococcal conjugate vaccine into a limited population

Background

The heptavalent pneumococcal conjugate vaccine (PCV-7) was introduced in high risk children and into the private market in Costa Rica in 2004 (<5% annual birth cohort). The aim of this study was to compare the Streptococcus pneumoniae serotype (ST) distribution, antibiotic resistance patterns and potential coverage before and after partial introduction of PCV-7.

Methods

A comparison between the S. pneumoniae isolates obtained and serotyped from the middle ear fluid (MEF) of Costa Rican children with otitis media between years 1999 and 2003 (before PCV-7 usage) and those isolates obtained from 2004 to 2008.

Results

A total of 145 and 218 MEF S. pneumoniae were serotyped between years 1999 and 2003 and 2004 and 2008, respectively. Considering a 19F outbreak observed between years 1999 and 2003, the following statistically significant changes in serotype distribution were detected between1999 and 2003 and 2004 and 2008: ST 3: 4.8–12.8% (P = 0.01); ST 11A: 0–4.1% (P = 0.01); ST 14: 3.5–21.1% (P < 0.001) and ST 19F: 52.4–18.3% (P < 0.05). Comparison of the two study periods demonstrated that during 2004 and 2008 a statistically significant decrease in penicillin non-susceptible serotypes (36.2–20.4% [P = 0.003]) and a statistically significant increase in trimethoprim-sulfametoxazole resistant serotypes (54.9–68.5%, respectively [P = 0.03]) was observed. Potential pneumococcal vaccines coverage between 1999 and 2003 and between 2004 and 2008 were: for PCV-7: 77.2–60.5%, respectively (P = 0.001); for the 10-valent conjugated vaccine (PCV-10): 78.6–61.4%, respectively (P = 0.0008) and for the 13-valent conjugated vaccine (PCV-13): 84.8–79.3%, respectively (P = 0.2).

Conclusions

Changes in the serotype distribution and antimicrobial susceptibility of MEF S. pneumoniae have been observed in Costa Rican children with OM. Because of the limited use of PCV-7 during the study period, these changes probably cannot be attributed to PCV-7 use. Between 2004 and 2008, PCV-13 offered the highest potential vaccine coverage.     

Serotype distribution and antimicrobial resistance of Streptococcus pneumoniae prior to introduction of the 10-valent pneumococcal conjugate vaccine in Brazil, 2000-2007

This study describes the serotype distribution and antibiotic resistance patterns among 397 S. pneumoniae meningitis case isolates recovered in Salvador, Brazil, during the period of 2000-2007, before introduction of the 10-valent pneumococcal conjugate vaccine.The active hospital-based surveillance showed a decline in the annual incidence rates of pneumococcal meningitis during the period of study, from 1.12 cases to 0.83 cases/100,000 persons for all age groups (P < 0.001), with an overall case-fatality rate of 28.6% (113 of 395) for all patients and 41.9% (57 of 136) for those <5 years of age. Serotypes 14 (n = 55; 13.9%), 3 (n = 32; 8.1%), 23F (n = 32; 8.1%), 19F (n = 31; 7.8%), 6B (n = 30; 7.6%), 18C (n = 28; 7.1%), and 6A (n = 20; 5%) were the most prevalent serotypes. In patients <5 years the estimated projected coverage of 7-, 10- and 13-valent conjugate vaccines was 74.3%, 75.7% and 83.1%, respectively. Antimicrobial susceptibility testing revealed that 22.1% (n = 88) of isolates were non-susceptible to penicillin, 56% were non-susceptible to trimethoprim/sulphamethoxazole, and 29.6% were non-susceptible to tetracycline. Nonsusceptibility to penicillin and cefotaxime was detected solely among serotype 14 isolates (n = 4; 1%). This study provides an important baseline to assess the impact of conjugate vaccine implantation on the epidemiology of meningitis due to Streptococcus pneumoniae in Salvador, Brazil.