Carriage prevalence, serotype distribution, and antimicrobial susceptibility among pneumococcal isolates recovered from adults with systemic lupus erythematosus

Antimicrobial Resistance in Streptococcus pneumoniae before and after the Introduction of Pneumococcal Conjugate Vaccines in Brazil: A Systematic Review

Streptococcus pneumoniae causes serious illnesses, such as pneumonia, bacteremia, and meningitis, mainly in immunocompromised individuals and those of extreme ages. Currently, pneumococcal conjugate vaccines (PCVs) are the best allies against pneumococcal diseases. In Brazil, the 10-valent and 13-valent PCVs have been available since 2010, but the threat of antimicrobial resistance persists and has been changing over time. We conducted a systematic review of the literature with works published since 2000, generating a parallel between susceptibility data on isolates recovered from colonization and invasive diseases before and after the implementation of PCVs for routine childhood use in Brazil. This systematic review was based on the Cochrane Handbook for Systematic Reviews of Interventions and Preferred Reporting Items for Systematic Literature Reviews and Meta-Analyses (PRISMA) guidelines. Despite the inclusion of PCVs at a large scale in the national territory, high frequencies of non-susceptibility to important drugs used in pneumococcal diseases are still observed, especially penicillin, as well as increasing resistance to macrolides. However, there are still drugs for which pneumococci have a comprehensive sensitivity profile.

Prevalence, capsular types, antimicrobial resistance and risk factors associated with pneumococcal carriage among children after long-term 10-valent pneumococcal conjugate vaccine use in Brazil

BACKGROUND

The 10-valent pneumococcal conjugate vaccine (PCV10) was introduced for childhood vaccination in Brazil's National Immunization Program in 2010. After nine years of PCV10 use, we investigated the carriage prevalence, capsular types, antimicrobial resistance and risk factors among children living in Niterói city, RJ, Brazil.

METHODS

Between September and December 2019, we conducted a cross-sectional study and recruited children under 6 years of age. Antimicrobial susceptibility was evaluated by the disk-diffusion method and MICs to beta-lactams and macrolides were determined by E-test®. Capsular types were deduced by multiplex PCR. Logistic regression was used to predict risk factors for pneumococcal carriage.

RESULTS

Seventy-five (17.4%) of the 430 children were pneumococcal carriers. The most frequent capsular types were 6C/D (14.7%), 11A/D (13.3%), and 23B (9.3%). PCV10 serotypes represented 5.3%. All isolates were susceptible to levofloxacin, linezolid, rifampicin, and vancomycin. Penicillin non-susceptible pneumococci (PNSP) made up 37.3%, with penicillin and ceftriaxone MICs ranging from 0.12 to 4.0 μg/ml and 0.064-4.0 μg/ml, respectively. Of the 19 (25.3%) erythromycin-resistant (ERY-R) isolates (macrolide MICs of 6 to >256 μg/ml), most had the cMLS_B phenotype (84.2%) and carried the erm(B) gene (73.7%). We detected 17 (22.6%) multidrug-resistant (MDR) isolates, strongly associated with serotype 6C/D. Presence of any symptoms, chronic diseases, childcare center attendance, living with young siblings, slum residence, and unstable income were predictors of pneumococcal carriage.

CONCLUSIONS

Long-term universal childhood use of PCV10 has nearly eliminated carriage with PCV10 serotypes, but the high frequency of MDR isolates, especially associated with serotype 6C/D, remains a concern. Replacing PCV10 with PCV13 should reduce the proportion of ERY-R isolates and PNSP by at least 14% and 18%, respectively.

Combined 13-valent pneumococcal conjugate and 23-valent pneumococcal polysaccharide vaccine regimens for adults with systemic lupus erythematosus: Does the sequence of pneumococcal vaccination affect immunogenicity responses? A single-center cohort study in Brazil

OBJECTIVE

A combination of 13-valent pneumococcal conjugate vaccine (PCV13) and 23-valent pneumococcal polysaccharide vaccine (PPSV23) is currently recommended for adults with systemic lupus erythematosus (SLE). However, data on the immunogenicity elicited by sequential pneumococcal vaccination in this patient population are scarce. In this study, we compared short-term antibody responses to both PCV13/PPSV23 (≥8-week interval) and PPSV23/PCV13 (≥12-month interval) vaccination strategies in pneumococcal vaccine-naive adults with SLE.

METHODS

This longitudinal, open-label, quasi-randomized study was performed in a single-center cohort of adults (18 years or older) with SLE. In both vaccination groups, blood samples were collected immediately before administering the first dose of the pneumococcal vaccine (timepoint T0), 4-6 weeks after the priming dose (T1), and 4-6 weeks after the booster dose (T2). We focused on the 12 shared serotypes between PCV13 and PPSV23, and compared the following immunogenicity outcomes between the groups at T2: anti-pneumococcal antibody geometric mean concentration (ApAb GMC), fold increase in ApAb levels (FI-ApAb), overall seroprotection rate, and overall seroconversion rate. The protective level for each pneumococcal serotype was set at 1.3 μg/mL. We used the multi-analyte immunodetection method to determine serum levels of ApAbs.

RESULTS

Thirty-four patients with SLE were screened between April 2019 and January 2020, and 16 of them (mean age: 39.4 years, 87.5% female, and 100% on immunosuppressants) had evaluable immunogenicity results at T2. The median time elapsed between the pneumococcal vaccinations was 56 days in the PCV13/PPSV23 group (n = 11 patients) and 16 months in the PPSV23/PCV13 group (n = 5 patients). Priming with PCV13 (PCV13/PPSV23 group), as opposed to PPSV23 (PPSV23/PCV13 group), yielded significantly better results regarding FI-ApAb, overall seroconversion rate, and overall seroprotection rate 4-6 weeks after each pneumococcal vaccination. A trend toward augmented ApAb GMC in the patients who received the PCV13/PPSV23 sequence was also observed. No relevant safety issues were identified with sequential pneumococcal vaccination.

CONCLUSION

The PCV13-priming PPSV23-boost strategy in adults with SLE induced greater antibody responses for most immunogenicity outcomes than those elicited by the PPSV23/PCV13 strategy.