Clinical characteristics, antimicrobial resistance, and risk factors for mortality in paediatric invasive pneumococcal disease in Beijing, 2012-2017

Background

To analyse clinical characteristics, antibiotic susceptibility, and risk factors for mortality in paediatric invasive pneumococcal disease (IPD) in Beijing.

Methods

Paediatric IPD patients in our hospital were retrospectively collected from 2012 to 2017. Clinical manifestations, laboratory tests, antimicrobial susceptibility and serotype of isolates, and risk factors for mortality of IPD were analysed.

Results

Overall, 186 IPD cases were enrolled. The major manifestations were meningitis (76), pneumonia with bacteraemia (60), bacteraemia without focus (21), and pneumonia with empyaema (22). Of 72 cases with underlying diseases, leukaemia (18.0%), congenital heart disease (15.3%), primary immunodeficiency disease (12.5%), nephrotic syndrome (12.5%), and cerebrospinal fluid leakage (12.5%) were most common. In total 96.9% of isolates would have been covered by the pneumococcal conjugate vaccine (PCV13), including 19F (32.8%), 19A (23.4%), 4 (17.2%), and 23F (9.4%). Nonsusceptibility rates of penicillin, cefotaxime, and cefepime among nonmeningitis patients increased between 2012 and 2017; The mortality rate was 21.5%. Meningitis, respiratory failure, multiple organ failure, and white blood cell count < 4000 cells/μL were independent risk factors for mortality.

Conclusion

Meningitis was the most common clinical manifestation of IPD, and was frequently associated with death. Strains in the PCV13 vaccine would cover most of the cases, and so wider use of PCV13 should be considered.

Cost-effectiveness analysis of domestic 13-valent pneumococcal conjugate vaccine for children under 5 years of age in mainland China

Background: The first Chinese domestic 13-valent pneumococcal conjugate vaccine (WoAnxin®, PCV-13) is available for children aged 2 months to 5 years and is more economical than import vaccine with equal safety and immunogenicity. However, the cost-effectiveness of this new PCV-13 for children <5 years in mainland China is not clear. Methods: In the present study, we developed a Markov model under societal perspective to evaluate the incremental cost-effectiveness ratios (ICERs) of five birth cohorts of 100,000 Chinese infants across four alternative vaccination programs:1) no vaccination; 2) vaccinate 4 doses of new PCV-13 for children aged 2 to 6 months; 3) vaccinate 3 doses of new PCV-13 for children aged 7 to 11 months; 4) vaccinate 2 doses of new PCV-13 for children aged 12 to 23 months; 5) vaccinate 1 dose of new PCV-13 for children aged 2 to 5 years. We conducted one-way and probability sensitivity analysis to determine the uncertainty of the model findings. Results: We found that with awillingness-to-pay (WTP) threshold of three-times Chinese per-capita gross domestic product (GDP) all vaccination programs were cost-effective compared to no vaccination and children aged 2 to 5 years received 1 dose of new PCV-13 would incur the lowest additional cost of US$2417 per quality-adjusted-life-years (QALYs) compare with other vaccination programs ($15394/QALYs for 4 doses program, $9292/QALYs for 3 doses program, $4445/QALYs for 2 doses program). Conclusions: According to our results, China should give priority to incorporating new PCV-13 into its national immunization program.

Phenotypic and molecular characterization of macrolide resistance mechanisms among Streptococcus pneumoniae isolated in Tunisia

Introduction. Streptococcus pneumoniae is responsible for many community infections, with the main ones being pneumonia and meningitis. Pneumococcus has developed increased resistance to multiple classes of antibiotics. The evolution of antibiotic resistance in pneumococcus was influenced by changes in serotype distribution under vaccine selection pressure.Aim. The aim of this study was to determine the genes involved in macrolide resistance, the antimicrobial susceptibility, the serotype distribution and the spread of international antibiotic-resistant clones among clinical isolates of S. pneumoniae.Methodology. We investigated 86 erythromycin-resistant S. pneumoniae strains isolated from respiratory (n=74) or non-respiratory (n=12) samples in Tunisia. Antimicrobial susceptibility was tested using the disk diffusion method. Macrolide-resistant strains were analysed by polymerase chain reaction (PCR) for ermA, ermB, mefA and msrD. We also investigated the macrolide resistance mechanisms in eight isolates (9.3%) by sequencing the L4 and L22 riboprotein-coding genes, plus relevant segments of the three 23S rRNA genes. Capsular serotypes were detected by multiplex PCR. Sequence types (STs) were explored using multilocus sequence typing (MLST).Results. Among the 86 studied strains, 70 (81.4 %) were resistant to penicillin G. The prevalent serotypes were 19F, 14, 19A and 23F. We observed that the cMLSB phenotype (66/86, 76.7%) was the most common in these pneumococci. In addition, ermB was the most frequent resistance gene. No mutation in ribosomal protein L22 or L4 or 23S rRNA was detected. Overall, 44 STs were identified in this study, including 16 that were described for the first time. Resistance to lincomycin, tetracycline and trimethoprim/sulfamethoxazole was observed in 55 (64 %), 34 (39.5 %) and 31 (36 %) isolates, respectively. Furthermore, an increase in fluoroquinolone use in particular may lead to the emergence of levofloxacin-resistant strains. Multidrug resistance was observed in 83 isolates (96.5%). Three global antibiotic-resistant clones were identified: Denmark¹⁴ ST230, Portugal^19F ST177 and Spain^9V ST156.Conclusion. This study shows that macrolide resistance among S. pneumoniae isolated in Tunisia is mainly related to target site modification. Our observations demonstrate a high degree of genetic diversity and capsular types among strains resistant to macrolides.

Nasopharyngeal pneumococcal carriage in healthy Turkish children after 13-valent conjugated pneumococcal vaccine implementation in the national immunization program

BACKGROUND

In Turkey, pneumococcal conjugated vaccine (PCV) was introduced to the national immunization program as PCV7 in 2008, and was replaced with PCV13 in 2011. The aims of this study were to investigate the effects of PCV13 on nasopharyngeal pneumococcal carriage (NPC) by determining the serotype distribution, and to identify risk factors for carriage, in healthy Turkish children.

METHODS

This prospective study was conducted on 500 healthy children aged 0-13 years between April and November 2014. Nasopharyngeal swab samples were taken, and molecular method for capsular serotyping was performed by multiplex PCR.

RESULTS

Of 500 children, 43.4% were unvaccinated with a PCV (7- or 13-valent), 56.6% were vaccinated and The NPC rate was found to be 9.8%. Of 49 positive Streptococcus pneumoniae isolates, 26 (53%) were PCV13 vaccine strains (VSs), and 17 (34.7%) were non-VS. Six isolates (12.2%) were not typeable by the method applied. The most common serotypes detected were serotype 3 (18.3%), serotype 19F (14.2%), serotype 6A/B (8.1%), serotype 11A (8.1%), and serotype 15B (8.1%). The total coverage rate of the PCV13 serotypes was 60.4%.

CONCLUSION

A significant decrease in carriage rate was detected within three years after the introduction of PCV13 in Turkey. However, the nasopharyngeal carriage of PCV13 strains was found to be interestingly high.

Serotype distribution and antimicrobial resistance patterns of invasive pneumococcal disease isolates from children in mainland China-a systematic review

OBJECTIVES

This study aimed to review and report the serotype distribution and antimicrobial resistance patterns of invasive pneumococcal disease (IPD) isolates, as this information is important for policy making since China has not adopted any pneumococcal vaccines in the national immunization schedule.

METHODS

A systematic review of the published literature from January 2000 to December 2018 was performed to identify articles that describe the serotype and/or antimicrobial resistance patterns of IPD cases in children in mainland China. Analysis of the extracted data was performed with the Microsoft Excel spreadsheet program. The percentage of the serotypes was calculated by dividing the number of isolates for each serotype with the total number of isolates included in all the studies. The theoretical impact of the vaccine was estimated by calculating the percentage of isolates that exhibited the serotypes included in the vaccines. The prevalence of antimicrobial resistance was defined as the number of isolates that were resistant divided by the total number of isolates tested for resistance to the specific antimicrobial agent.

RESULTS

Forty-two articles were screened in the preliminary search, of which sixteen fulfilled inclusion criteria and were included in the final analysis. The predominant serotypes were 19A, 19F, 14, 23F, and 6B, and the estimated impact of PCV13 was 90.4%. The isolates exhibited a high frequency of resistance to cefuroxime, cefaclor, and erythromycin.

CONCLUSIONS

It is necessary for Chinese children to receive PCV13. Clinical workers should pay attention to the high frequency of resistance to antimicrobial agents.

Serotype distribution of Streptococcus pneumoniae and potential impact of pneumococcal conjugate vaccines in China: A systematic review and meta-analysis

OBJECTIVE

Thirteen-valent pneumococcal conjugate vaccines (PCV13) was licensed for optional use in mainland China since 2017, but the uptake is low. To update the research evidence for the pneumococcal serotype distribution of pre-PCV era and to estimate the potential impact of PCVs, we performed a meta-analysis on the relevant publications concerning the Chinese population.

METHODS

This systematic review and meta-analysis were conducted on the pneumococcal serotype distribution publications in mainland China from 2000 to 2016. The literature was searched in PubMed, Ovid-EMBASE, Web of Science, CNKI and Wanfang. Heterogeneity and publication bias were tested by I2, meta-regression, Egger's and Begg's test. The pneumococcal serotype and vaccine serotype coverage rates were pooled using the random-effects model in Stata SE 12.0.

RESULTS

In total, 85 publications were included. Of all 16,945 included pneumococcal isolates, the most common serotypes/serogroups were 19F, 19A, 23F, 14, and 6B, that from children were the same as above, that from adults≥18 years were 19, 3, 6, 23, and 14. Among isolates from children <18 years, the pooled coverage for PCV10 serotypes was 52.3%, that for PCV13 was 68.4% and that for PPSV23 was 65.5%. Regarding individuals ≥18 years, the pooled coverage for PCV10 serotypes was 29.7%, that for PCV13 was 49.5% and that for PPSV23 was 50.7%. Serotype prevalence and vaccine serotype coverage varied by age group, source, and region.

CONCLUSIONS

The most common pneumococcal serotype in mainland China was 19F. The serotype coverage rates of PCV13 and PPSV23 were 50%-68% in mainland China.

Cost-effectiveness analysis of routine 13-valent pneumococcal conjugate vaccinations in Chinese infants

BACKGROUND

This study aimed to evaluate the cost-effectiveness of the 13-valent pneumococcal conjugate vaccine (PCV-13) compared to a no vaccination strategy in Chinese infants.

METHODS

A Markov process model was developed to examine the outcomes of PCV-13 against a no vaccination strategy using data and assumptions adapted for relevance to China. Outcomes over a lifetime horizon are presented. One-way and probabilistic sensitivity analyses were performed to determine the uncertainty.

RESULTS

Compared to no vaccination, a PCV-13 vaccination program would provide a gain of 0.009 additional quality-adjusted life years (QALYs) per subject. From the health care and societal perspectives, the incremental costs per QALY were $20,709 and 18,483, respectively. When herd effect was included, the cost effectiveness of the PCV-13 vaccination strategy was notably improved. The lower price of PCV-13 will improve the cost-effectiveness.

CONCLUSIONS

The PCV-13 vaccination is likely to be cost-effective at the current Chinese prices and ceiling threshold ($8,382).

Antimicrobial susceptibility and fluctuations in clonal complexes of serogroup 6 Streptococcus pneumoniae isolates collected from children in Beijing, China, between 1997 and 2016

This study examined the antimicrobial susceptibility patterns and clonal complex (CC) characteristics of serogroup 6 Streptococcus pneumoniae isolates collected from children in Beijing, China, between 1997 and 2016. Serotypes were determined using the Quellung reaction, and the antimicrobial susceptibility profiles of the isolates were determined using the disc-diffusion method or by E-test. Sequence types (STs) were assigned based on multilocus sequence typing. A total of 250 isolates were examined, with 55.2%, 30.0%, 12.8%, and 2.0% of isolates identified as serotypes 6A, 6B, 6C, and 6D, respectively. All of the isolates were susceptible to levofloxacin and vancomycin, and the non-suceptibitility rate to penicillin was 41.6%. Eighty-two distinct STs, assigned to 13 CCs and 28 singletons, were identified. CC982 was the most prevalent CC amongst serotype 6A isolates (34%), followed by CC9789 and CC3173. Amongst serotype 6B isolates, CC90 and CC4542 were the most common, accounting for 25.3% and 14.7% of isolates respectively. Over the study period, the prevalence of CC982, CC4542, and CC4536 isolates showing susceptibility to penicillin and cefuroxime decreased, and the proportion of CC3173, CC9789, CC855, and CC902 isolates showing non-susceptibility to these two antibiotics increased.

Serotype distribution, antibiotic resistance patterns and molecular characteristics of serogroup 6 Streptococcus pneumoniae isolates collected from Chinese children before the introduction of PCV13

OBJECTIVES

Streptococcus pneumoniae is an important pathogen in infectious diseases worldwide, and serogroup 6 S. pneumoniae strains are very common in China. This study investigated the serotype distribution, antibiotic resistance patterns and molecular characteristics of 215 serogroup 6 S. pneumoniae isolates collected from hospitalised children in China during 2013-2016.

METHODS

Serotypes were determined using the Quellung reaction with antisera. Antibiotic resistance against 11 antimicrobials was tested by Etest or the disk diffusion method. Sequence types (STs) were assigned using multilocus sequence typing (MLST). Data analysis was performed with WHONET 5.6 software.

RESULTS

The percentages of serotype 6A, 6B, 6C and 6D among the 215 serogroup 6 isolates were 50.7% (109/215), 36.3% (78/215), 12.6% (27/215) and 0.5% (1/215), respectively. All isolates were susceptible to levofloxacin and were resistant to erythromycin. No isolate was resistant to parenteral penicillin, but the intermediate and resistant rates reached 72.6% (156/215) and 5.1% (11/215), respectively, based on the oral breakpoint. Sixty-seven STs were detected, with 14 STs being newly assigned. The most common clonal complexes (CCs) were CC3173 (26.5%; 57/215), CC9789 (13.5%; 29/215), CC90 (13.0%; 28/215) and CC902 (8.8%; 19/215), and the non-susceptibility rates of these four CCs against penicillin and cefuroxime (penicillin, 98.2%, 100%, 100% and 100%, respectively; cefuroxime, 98.2%, 100%, 96.4% and 94.7%, respectively) were higher than the overall level of serogroup 6 isolates (penicillin, 77.7%; cefuroxime, 70.2%).

CONCLUSIONS

Serotype 6A is the most common serotype of serogroup 6 S. pneumoniae strains in Chinese children, and different CCs/STs express diverse antibiotic resistance patterns.