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Molecular epidemiology of pneumococcal carriage among children with upper respiratory tract infections in Hanoi, Vietnam.

ABSTRACT: To investigate the molecular epidemiology of pneumococcal nasopharyngeal carriage in Hanoi, Vietnam, we studied 84 pneumococcal strains retrieved from children with upper respiratory tract infections. Serotypes 23F (32%), 19F (21%), 6B (13%), and 14 (10%) were found most often. A significant number of strains were antibiotic resistant. Fifty-two percent of the strains were (intermediate) resistant to penicillin, 87% were (intermediate) resistant to co-trimoxazole, 76% were resistant to tetracycline, 73% were resistant to erythromycin, and 39% were (intermediate) resistant to cefotaxime. Seventy-five percent were resistant to three or more classes of antibiotics. A high degree of genetic heterogeneity among the penicillin resistance genes was observed. In addition, the tetracycline resistance gene tet(M) and the erythromycin resistance gene erm(B) were predominantly observed among the isolates. Molecular analysis of the 84 isolates by restriction fragment end labeling (RFEL) revealed 35 distinct genotypes. Twelve of these genotypes represented a total of eight genetic clusters with 61 isolates (73%). The two largest clusters contained 24 and 12 isolates, and the isolates in those clusters were identical to the two internationally spreading multidrug-resistant clones Spain 23F-1 and Taiwan 19F-14, respectively. The remaining RFEL types were Vietnam specific, as they did not match the types in our reference collection of 193 distinct RFEL types from 16 countries. Furthermore, 57 of the 61 horizontally spreading isolates (93%) in the eight genetic clusters were covered by the seven-valent conjugate vaccine, whereas this vaccine covered only 43% of the isolates with unique genotypes. According to the serotype distribution of the nasopharyngeal pneumococcal isolates, this study suggests a high potential benefit of the seven-valent pneumococcal conjugate vaccine for children in Hanoi.

SUBMITTER: Bogaert D

PROVIDER: S-EPMC139650 | biostudies-literature | 2002 Nov

REPOSITORIES: biostudies-literature

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Molecular epidemiology of pneumococcal carriage among children with upper respiratory tract infections in Hanoi, Vietnam.

Bogaert D D Ha N T NT Sluijter M M Lemmens N N De Groot R R Hermans P W M PW

Journal of clinical microbiology 20021101 11

To investigate the molecular epidemiology of pneumococcal nasopharyngeal carriage in Hanoi, Vietnam, we studied 84 pneumococcal strains retrieved from children with upper respiratory tract infections. Serotypes 23F (32%), 19F (21%), 6B (13%), and 14 (10%) were found most often. A significant number of strains were antibiotic resistant. Fifty-two percent of the strains were (intermediate) resistant to penicillin, 87% were (intermediate) resistant to co-trimoxazole, 76% were resistant to tetracycl ...[more]

PMID: 12409349

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Project description:A total of 125 isolates were recovered from adenoids and/or nasopharynx of 170 children aged 2 to 5 from south-east Poland; they had undergone adenoidectomy for recurrent and/or persistent symptoms of upper respiratory tract infections. Pneumococcal isolates were analyzed by phenotyping (serotyping and antimicrobial resistance tests) and genotyping together with the clonality of the pneumococcal isolates based on resistance determinants, transposon distribution and multilocus sequence typing (MLST). Serotypes 19F, 6B and 23F constituted 44.8% of the isolates. Among all of the strains, 44.8% showed decreased susceptibility to penicillin and resistance to co-trimoxazole (52.8%), tetracycline (38.4%), erythromycin (53.6%), clindamycin (52.8%) and chloramphenicol (27.2%) was observed. Tn6002 was found in 34.8% of erythromycin-resistant isolates while composite Tn2010-in 16.7% of erm(B)-carrying isolates that harboured also mef(E) gene. Tn3872-related elements were detected in 27.3% of erythromycin-resistant strains. In the majority of chloramphenicol-resistant catpC194-carrying isolates (79.4%), ICESp23FST81-family elements were detected. The genotyping showed that pneumococcal population was very heterogeneous; 82 sequence types (STs) were identified, and the most frequent contributed to not more than 8% of the isolates. Nearly 44% STs were novel, each of them was recovered only from one child. Four STs belonged to one of the 43 worldwide spread resistant pneumococcal clones currently accepted by Pneumococcal Molecular Epidemiology Network (PMEN), i.e. Spain 9V-3, Spain 23F-1, Norway NT-42 and Poland 6B-20, accounting for 12 (16.7%) of the 75 nonususceptible isolates, and five STs were single-locus variants of PMEN resistant clones (England 14-9, Spain 9V-3, Spain 23F-1, Greece 21-30, Denmark 14-32), accounting 9 (12%) of nonsusceptible isolates. A few MDR clones belonging to 6B and 19F serotypes found among preschool children emphasizes rather the role of clonal dissemination of local strains in the community than international clones spreading in the increase of resistance among pneumococcal strains.

Project description:BackgroundMycoplasma pneumoniae is thought to be a common cause of respiratory tract infections (RTIs) in children. The diagnosis of M. pneumoniae RTIs currently relies on serological methods and/or the detection of bacterial DNA in the upper respiratory tract (URT). It is conceivable, however, that these diagnostic methods also yield positive results if M. pneumoniae is carried asymptomatically in the URT. Positive results from these tests may therefore not always be indicative of a symptomatic infection. The existence of asymptomatic carriage of M. pneumoniae has not been established. We hypothesized that asymptomatic carriage in children exists and investigated whether colonization and symptomatic infection could be differentiated by current diagnostic methods.Methods and findingsThis study was conducted at the Erasmus MC-Sophia Children's Hospital and the after-hours General Practitioners Cooperative in Rotterdam, The Netherlands. Asymptomatic children (n?=?405) and children with RTI symptoms (n?=?321) aged 3 mo to 16 y were enrolled in a cross-sectional study from July 1, 2008, to November 30, 2011. Clinical data, pharyngeal and nasopharyngeal specimens, and serum samples were collected. The primary objective was to differentiate between colonization and symptomatic infection with M. pneumoniae by current diagnostic methods, especially real-time PCR. M. pneumoniae DNA was detected in 21.2% (95% CI 17.2%-25.2%) of the asymptomatic children and in 16.2% (95% CI 12.2%-20.2%) of the symptomatic children (p?=?0.11). Neither serology nor quantitative PCR nor culture differentiated asymptomatic carriage from infection. A total of 202 children were tested for the presence of other bacterial and viral pathogens. Two or more pathogens were found in 56% (63/112) of the asymptomatic children and in 55.5% (50/90) of the symptomatic children. Finally, longitudinal sampling showed persistence of M. pneumoniae in the URT for up to 4 mo. Fifteen of the 21 asymptomatic children with M. pneumoniae and 19 of the 22 symptomatic children with M. pneumoniae in this longitudinal follow-up tested negative after 1 mo.ConclusionsAlthough our study has limitations, such as a single study site and limited sample size, our data indicate that the presence of M. pneumoniae in the URT is common in asymptomatic children. The current diagnostic tests for M. pneumoniae are unable to differentiate between asymptomatic carriage and symptomatic infection.

Project description:ImportanceAn association between pneumococcal nasopharyngeal carriage and invasive pneumococcal disease (IPD) has been previously established. However, it is unclear whether the decrease in IPD incidence observed after implementation of nonpharmaceutical interventions (NPIs) during the COVID-19 pandemic was associated with concomitant changes in pneumococcal carriage and respiratory viral infections.ObjectiveTo assess changes in IPD incidence after the implementation of NPIs during the COVID-19 pandemic and examine their temporal association with changes in pneumococcal carriage rate and respiratory viral infections (specifically respiratory syncytial virus [RSV] and influenza cases) among children in France.Design, setting, and participantsThis cohort study used interrupted time series analysis of data from ambulatory and hospital-based national continuous surveillance systems of pneumococcal carriage, RSV and influenza-related diseases, and IPD between January 1, 2007, and March 31, 2021. Participants included 11 944 children younger than 15 years in France.ExposuresImplementation of NPIs during the COVID-19 pandemic.Main outcomes and measuresThe estimated fraction of IPD change after implementation of NPIs and the association of this change with concomitant changes in pneumococcal carriage rate and RSV and influenza cases among children younger than 15 years. The estimated fraction of change was analyzed using a quasi-Poisson regression model.ResultsDuring the study period, 5113 children (median [IQR] age, 1.0 [0.6-4.0] years; 2959 boys [57.9%]) had IPD, and 6831 healthy children (median [IQR] age, 1.5 [0.9-3.9] years; 3534 boys [51.7%]) received a swab test. Data on race and ethnicity were not collected. After NPI implementation, IPD incidence decreased by 63% (95% CI, -82% to -43%; P < .001) and was similar for non-13-valent pneumococcal conjugate vaccine serotypes with both high disease potential (-63%; 95% CI, -77% to -48%; P < .001) and low disease potential (-53%; 95% CI, -70% to -35%; P < .001). The overall pneumococcal carriage rate did not significantly change after NPI implementation (-12%; 95% CI, -37% to 12%; P = .32), nor did the carriage rate for non-PCV13 serotypes with high disease potential (-26%; 95% CI, -100% to 52%; P = .50) or low disease potential (-7%; 95% CI, -34% to 20%; P = .61). After NPI implementation, the estimated number of influenza cases decreased by 91% (95% CI, -74% to -97%; P < .001), and the estimated number of RSV cases decreased by 74% (95% CI, -55% to -85%; P < .001). Overall, the decrease in influenza and RSV cases accounted for 53% (95% CI, -28% to -78%; P < .001) and 40% (95% CI, -15% to -65%; P = .002) of the decrease in IPD incidence during the NPI period, respectively. The decrease in IPD incidence was not associated with pneumococcal carriage, with carriage accounting for only 4% (95% CI, -7% to 15%; P = .49) of the decrease.Conclusions and relevanceIn this cohort study of data from multiple national continuous surveillance systems, a decrease in pediatric IPD incidence occurred after the implementation of NPIs in France; this decrease was associated with a decrease in viral infection cases rather than pneumococcal carriage rate. The association between pneumococcal carriage and IPD was potentially modified by changes in the number of RSV and influenza cases, suggesting that interventions targeting respiratory viruses, such as immunoprophylaxis or vaccines for RSV and influenza, may be able to prevent a large proportion of pediatric IPD cases.

Dataset Information

Molecular epidemiology of pneumococcal carriage among children with upper respiratory tract infections in Hanoi, Vietnam.

Publications

Molecular epidemiology of pneumococcal carriage among children with upper respiratory tract infections in Hanoi, Vietnam.

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