Comparison of PCV-10 and PCV-13 vaccine coverage for invasive pneumococcal isolates obtained across Canadian geographic regions, SAVE 2011 to 2017

Comparing serotype coverage of pneumococcal vaccines with PCV21 (V116), a new 21-valent conjugate pneumococcal vaccine, and the epidemiology of its eight unique Streptococcus pneumoniae serotypes (15A, 15C, 16F, 23A, 23B, 24F, 31 and 35B) causing invasive pneumococcal disease in adult patients in Canada: SAVE study, 2018-21

BACKGROUND

V116 is a novel 21-valent pneumococcal conjugate vaccine (PCV) intended for use in adults.

OBJECTIVES

To estimate current V116 serotype coverage in adult patients in Canada compared with PCV15, PCV20 and PPSV23 vaccines, and to describe isolate demographics for the eight unique serotypes (15A, 15C, 16F, 23A, 23B, 24F, 31 and 35B) covered by V116.

METHODS

From 2018 to 2021 inclusive, the SAVE study collected 5854 invasive pneumococcal disease (IPD) isolates as part of a collaboration between the Canadian Antimicrobial Resistance Alliance and the Public Health Agency of Canada-National Microbiology Laboratory. Serotypes were determined by Quellung reaction and antimicrobial susceptibility testing performed using the CLSI broth microdilution method.

RESULTS

For adult patients (≥18 years), adults 50-64 years and adults ≥65 years, respectively, IPD isolate coverage was PCV15 (42.7%; 41.0%, 39.8%), PCV20 (59.0%; 60.2%, 52.2%), PPSV23 (70.4%; 75.1%, 60.0%), V116 (78.9%; 76.3%, 81.5%) and V116 plus PCV20 (92.2%; 91.0%, 89.3%). The eight unique V116 serotypes accounted for 19.7% and 26.8% of IPD isolates from adults and adults ≥65 years, respectively. Among the eight unique V116 serotypes, 15A and 23A demonstrated the highest rates of MDR (17.0% and 10.2%, respectively); 6.7% of 15A isolates were XDR.

CONCLUSIONS

V116 provided significantly (P < 0.05) greater coverage than PCV15, PCV20 and PPSV23 for adults, including older adults, across all Canadian geographic regions, and against IPD isolates with common antimicrobial resistance phenotypes, including MDR. The eight unique V116 serotypes accounted for a higher proportion of IPD isolate serotypes in patients aged ≥65 years than younger adults.

Phenotypic and molecular characterization of Streptococcus pneumoniae serotype 3 isolates from blood and respiratory samples in Canada: CANWARD 2007-21

BACKGROUND

Lower respiratory infections and invasive disease caused by Streptococcus pneumoniae serotype 3 remain major clinical challenges around the world, despite widespread availability of updated vaccines.

METHODS

As part of CANWARD, antimicrobial susceptibility testing and serotyping were performed on all S. pneumoniae isolates from 2007 to 2021. A subset of 226/264 (85.6%) serotype 3 isolates were selected for WGS to determine sequence type (ST)/clonal cluster (CC) and correspondence of antimicrobial resistance determinants (erm, mefAE, tetM, cat, folA, folP) with resistance phenotype.

RESULTS

Of the 3,039 S. pneumoniae isolates obtained from 2007 to 2021, 8.7% (n = 264) were serotype 3, with 64.0% of respiratory origin and 36.0% from blood. Of 226 sequenced serotype 3 isolates, 184 (81.4%) were ST180 (GPSC12). The proportion of ST8561 (single locus variant of ST180) increased from 7.2% to 16.6% during the study period. An increasing proportion of serotype 3 isolates had phenotypic resistance (P = 0.0007) and genetic resistance determinants (P = 0.004), comparing 2017-21 to 2007-11, largely due to a recently expanded ST180 clade with cat, tetM and mef determinants.

CONCLUSIONS

S. pneumoniae serotype 3 from GPSC12 continues to dominate throughout Canada, with an increase in the proportion of ST8561. The proportion of serotype 3 isolates that are phenotypically resistant and with genetic resistance determinants is increasing over time, reflecting a global increase in GPSC12 genotypes with known resistance determinants. Phylogenomic characterization of isolates collected over time and from around the world may facilitate improved treatment and enhanced prevention strategies, including new vaccines with activity against S. pneumoniae serotype 3.

Changes in pneumococcal serotypes distribution and penicillin resistance in healthy children five years after generalization of PCV10

Objective

Streptococcus pneumoniae (S. pneumoniae) nasopharyngeal carriage has significantly decreased after the generalization of pneumococcal vaccination worldwide. This study sought to investigate changes in S. pneumoniae carriage rates, serotype distribution and penicillin non-susceptibility following the generalization of 10-valent pneumococcal conjugate vaccine.

Methods

A prospective study was conducted in Marrakesh, Morocco, between 2017 and 2018, among healthy children attending vaccination centers. We collected nasopharyngeal swabs and questionnaire data for each child. Using univariate logistic regression, we analyzed the association between S. pneumoniae carriage and various risk factors. Comparisons of serotype diversity and penicillin resistance between 2017 and 2018 and the period before introduction of vaccination (2008-2009, n = 660) were performed using Simpson index and the chi-squared test, respectively.

Results

During 2017-2018, 515 children aged between 6 and 36 months participated. The S. pneumoniae carriage rate was 43.3%. Looking at the distribution serotypes, the rate of PCV10 serotypes rate was only 9.6%. Among non-vaccine serotypes, an increase in serotypes 6C/6D (22; 14%), 19B/19C (17; 10.8%), and 15B/15C (11; 7%) was observed. A particular increase in serotype diversity was also observed after the generalization of PCV10 (p < 0.001). S. pneumoniae non-susceptible to penicillin decreased, reaching a rate of 26.6% in 2017-2018.

Conclusion

The significant change in S. pneumoniae carriage, serotype distribution, and penicillin resistance highlights the effectiveness of the pneumococcal conjugate vaccine among children in Marrakesh, Morocco.

Vaccination against Streptococcus pneumoniae in Children Born between 2015 and 2018 in Poland-How Has the Introduction of Free Compulsory Pneumococcal Vaccination Affected Its Uptake?

Starting from 2017, pneumococcal vaccination was added to the Polish vaccination calendar as mandatory for all children born after 2016. The 10-valent conjugate vaccine was selected as mandatory and therefore free of charge. This paper aims to examine the impact of introducing mandatory vaccination on vaccine uptake. For this purpose, an analysis was conducted for 1595 vaccination record sheets from outpatient clinics in Wrocław and surrounding villages for children born 2015-2018. After the introduction of compulsory vaccination, the percentage of children fully vaccinated against pneumococcus increased (60.4% vs. 84.8%, p < 0.001). A significant decrease in the number of children who did not receive any dose of the vaccine was observed (27.8% to 3.3%, p < 0.001). The introduction of compulsory vaccination did not affect the completion of the pneumococcal schedule (11.8% vs. 11.9%). Compulsory PCV10 vaccination resulted in the less frequent choice of the 13-valent vaccine (72.3% vs. 19.9%, p < 0.001). More children in rural outpatient clinics were vaccinated against pneumococcus compared to urban outpatient clinics (84.8% vs. 70.8%, p < 0.001). The introduction of free pneumococcal vaccination increased the proportion of children vaccinated, although it did not affect the rate of discontinuation of the initiated schedule. In Poland, the increased popularity of the 10-valent vaccine at the expense of the 13-valent one translated into a change in the proportion of pneumococcal serotypes causing invasive pneumococcal disease.

Comparison of PCV10, PCV13, PCV15, PCV20 and PPSV23 vaccine coverage of invasive Streptococcus pneumoniae isolate serotypes in Canada: the SAVE study, 2011-20

BACKGROUND

As pneumococci evolve under vaccine, antimicrobial and other selective pressures, it is important to track isolates covered by established (PCV10, PCV13 and PPSV23) and new (PCV15 and PCV20) vaccine formulations.

OBJECTIVES

To compare invasive pneumococcal disease (IPD) isolates from serotypes covered by PCV10, PCV13, PCV15, PCV20 and PPSV23, collected in Canada from 2011 to 2020, by demographic category and antimicrobial resistance phenotype.

METHODS

IPD isolates from the SAVE study were initially collected by members of the Canadian Public Health Laboratory Network (CPHLN) as part of a collaboration between the Canadian Antimicrobial Resistance Alliance (CARA) and the Public Health Agency of Canada (PHAC). Serotypes were determined by quellung reaction, and antimicrobial susceptibility testing was performed using the CLSI broth microdilution method.

RESULTS

A total of 14 138 invasive isolates were collected from 2011 to 2020, with 30.7% of isolates covered by the PCV13 vaccine, 43.6% of isolates covered by the PCV15 vaccine (including 12.9% non-PCV13 serotypes 22F and 33F), and 62.6% of isolates covered by the PCV20 vaccine (including 19.0% non-PCV15 serotypes 8, 10A, 11A, 12F and 15B/C). Non-PCV20 serotypes 2, 9N, 17F and 20, but not 6A (present in PPSV23) represented 8.8% of all IPD isolates. Higher-valency vaccine formulations covered significantly more isolates by age, sex, region and resistance phenotype including MDR isolates. Coverage of XDR isolates did not significantly differ between vaccine formulations.

CONCLUSIONS

When compared with PCV13 and PCV15, PCV20 covered significantly more IPD isolates stratified by patient age, region, sex, individual antimicrobial resistance phenotypes and MDR phenotype.

Serotype Distribution and Antimicrobial Resistance of Streptococcus pneumoniae Causing Invasive Pneumococcal Disease in Korea Between 2017 and 2019 After Introduction of the 13-Valent Pneumococcal Conjugate Vaccine

Background

Streptococcus pneumoniae is a serious pathogen causing various infections in humans. We evaluated the serotype distribution and antimicrobial resistance of S. pneumoniae causing invasive pneumococcal disease (IPD) after introduction of pneumococcal conjugate vaccine (PCV)13 in Korea and investigated the epidemiological characteristics of multidrug-resistant (MDR) isolates.

Methods

S. pneumoniae isolates causing IPD were collected from 16 hospitals in Korea between 2017 and 2019. Serotyping was performed using modified sequential multiplex PCR and the Quellung reaction. Antimicrobial susceptibility tests were performed using the broth microdilution method. Multilocus sequence typing was performed on MDR isolates for epidemiological investigations.

Results

Among the 411 S. pneumoniae isolates analyzed, the most prevalent serotype was 3 (12.2%), followed by 10A (9.5%), 34 (7.3%), 19A (6.8%), 23A (6.3%), 22F (6.1%), 35B (5.8%), 11A (5.1%), and others (40.9%). The coverage rates of PCV7, PCV10, PCV13, and pneumococcal polysaccharide vaccine (PPSV)23 were 7.8%, 7.8%, 28.7%, and 59.4%, respectively. Resistance rates to penicillin, ceftriaxone, erythromycin, and levofloxacin were 13.1%, 9.2%, 80.3%, and 4.1%, respectively. MDR isolates accounted for 23.4% of all isolates. Serotypes 23A, 11A, 19A, and 15B accounted for the highest proportions of total isolates at 18.8%, 16.7%, 14.6%, and 8.3%, respectively. Sequence type (ST)166 (43.8%) and ST320 (12.5%) were common among MDR isolates.

Conclusions

Non-PCV13 serotypes are increasing among invasive S. pneumoniae strains causing IPD. Differences in antimicrobial resistance were found according to the specific serotype. Continuous monitoring of serotypes and antimicrobial resistance is necessary for the appropriate management of S. pneumoniae infections.

Cefiderocol: A Review in Serious Gram-Negative Bacterial Infections

Intravenous cefiderocol (Fetroja®; Fetcroja®) is the first siderophore cephalosporin approved for the treatment of adults with serious Gram-negative bacterial infections. Cefiderocol is stable against all four Ambler classes of β-lactamases (including metallo-β-lactamases) and exhibits excellent in vitro activity against many clinically relevant Gram-negative pathogens, including multidrug resistant strains. In randomized, double-blind clinical trials, cefiderocol was noninferior to imipenem/cilastatin for the treatment of complicated urinary tract infections (cUTI) and to meropenem for nosocomial pneumonia. Furthermore, in a pathogen-focused clinical trial in patients with carbapenem-resistant (CR) infections, cefiderocol showed comparable efficacy to best available therapy (BAT), albeit all-cause mortality rate was higher in the cefiderocol arm, the cause of which has not been established. Cefiderocol had a good tolerability and safety profile in clinical trials. Thus cefiderocol is a novel, emerging, useful addition to the current treatment options for adults with susceptible Gram-negative bacterial infections (including cUTI and nosocomial pneumonia) for whom there are limited treatment options.