Serotype distribution and antibiotic susceptibility of Streptococcus pneumoniae strains carried by children infected with human immunodeficiency virus.
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ABSTRACT:
SUBMITTER: Safari D
PROVIDER: S-EPMC4208773 | biostudies-other | 2014
REPOSITORIES: biostudies-other
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Project description:INTRODUCTION:Pakistan has one of the highest burdens of pneumococcal diseases in the world, but unfortunately studies in this demanding research area are limited in the region. Pneumococcal surface protein A (PspA) is the next generation pneumococcal vaccine candidate as the protein locates on the Streptococcus pneumoniae surface. Its gene, pspA, might be encoded by all pneumococci, and the protein has proven immunogenicity. The molecular characterization of PspA, pneumococcal serotype distribution and antibiotic susceptibility are important for regional diversity studies. METHODS:In this study, we examined 38 pneumococcal isolates from pneumococcal diseased (pneumonia/meningitis) patients blood or cerebrospinal fluid. There were no specific inclusion or exclusion criteria, but all the individuals [ages 1 month to 12 years (male/female)] had undergone no antibiotic treatment in at least the past 3 months and had no vaccination history. We investigated the serotype distribution, antibiotic susceptibility, prevalence of the PspA family and its active domain's fusion, expression and antigenicity. RESULTS:Our finding shows that serotype 19F is the most prevalent (23.6%) followed by 18B (15.78%) (non-vaccine type) in all isolated pneumococcal strains. All strains were susceptible to chloramphenicol and linezolid, while 80% were resistant to gentamycin. Genotyping revealed that ~ 80% (N = 31/38) of pneumococcal strains produce PspA belonging to family 2 and clade 3. We further selected three active domains of PspA (family 2 and clade 3) by in silico analysis, merged together into a fusion gene for expression study, and its antigenicity was analyzed by Western blotting. CONCLUSION:Serotypes 19F and 18B (non-vaccine type) are the most prevalent in the Pakistani pneumococcal isolates. The PspA family 2 proteins produced by Pakistani pneumococcal isolates have high sequence homologies with each other and differ from those produced by strains isolated in the rest of the world. The PspA fusion peptide had a proven antigenic response in western blotting, with no considerable correlation among pneumococcal serotypes, antibiotic susceptibility and PspA family/clade distribution.
| S-EPMC5986679 | biostudies-literature
Project description:Streptococcus pneumoniae is a major cause of invasive diseases worldwide. It spreads through an interindividual transmission, followed by usually harmless colonization of the host. Possible transmission differences reflecting intrinsic strain features (e.g., serotype and antibiotic susceptibility) have been little studied so far. In this study, we used epidemiological data from an interventional trial of S. pneumoniae carriage among kindergartners and developed a mathematical model to estimate the transmission parameters of the different strains isolated during that study. We found small but significant transmissibility differences between the observed serotypes: serotypes 3, 6A, and 19A were found to be the most epidemic, while serotypes 23F, 9V, and 14 were the least epidemic. Further analysis indicated that, within a serotype, susceptible and resistant strains had different abilities to be transmitted. Susceptible-to-resistant transmission rate ratios were computed for five serotypes; susceptible strains were significantly more epidemic than resistant strains for serotypes 6A (mean, 1.02) and 19F (1.05). Serotype 19A resistant strains were not outcompeted by susceptible strains (0.97). Nonsignificant trends were observed for serotypes 6B (1.01) and 15A (0.98). Our results support the existence of heterogeneous abilities of the different serotypes for host-to-host transmission. They also suggest that antibiotic susceptibility within a serotype affects this transmissibility. We conclude that pneumococcal strains should not be considered equally at-risk in terms of transmission. Further quantification of strain-specific epidemic potential is needed, especially in a context of extensive use of conjugate vaccines with the aim of preventing pneumococcal infections.
| S-EPMC3195016 | biostudies-literature
Project description:BackgroundGroup B Streptococcus (GBS) comprises the normal flora of the female urogenital tract and can be transferred to neonates during delivery, causing invasive diseases. This study was performed to investigate the colonization rate, antibiotic susceptibility, and serotype of GBS among Saudi pregnant women.Materials and methodsIn this cross-sectional study, vagino-rectal swabs from 400 pregnant women were collected over a period of one year. Identification of GBS isolates and determination of their antibiotic susceptibility were performed using the Microscan Walk Away system. The isolates were then typed using both latex agglutination and capsular gene-based multiplex polymerase chain reaction assays.ResultsSixty (15.0%) subjects were colonized by GBS, with serotype Ia as the dominant type (30.0%) followed by serotype III and V (25.0%, each). Only 43 (71.7%) isolates were typed by latex agglutination, whereas the remaining isolates were not typable or were non-specifically typed as compared to the genotyping assay, which revealed the specific type of each GBS isolate. The highest resistance rates were observed for erythromycin and clindamycin (16.7%, each), which were mainly restricted to the prevalent serotypes.ConclusionThis study is the first to report the distribution of GBS serotypes based on molecular genotyping in Saudi Arabia. GBS colonization was evident among pregnant women, and resistance to erythromycin and clindamycin was predominant among serotypes Ia, III, and V. Molecular genotyping using capsular gene-based multiplex PCR provided reliable typing of the investigated GBS isolates in terms of sensitivity and specificity as compared to conventional serotyping using latex agglutination.
| S-EPMC7113445 | biostudies-literature
Project description:BACKGROUND:To mitigate the burden of pneumococcal infections in Niger, a 13-valent pneumococcal vaccine, PCV13, was introduced for routine child vaccination in July 2014. In order to provide pre-vaccine baseline data and allow appreciation of changes on carriage due to vaccination, we analyzed retrospectively pneumococcal isolates obtained from healthy, 0 to 2 year old children prior to the vaccine introduction. METHODS:From June 5, 2007, to May 26, 2008, 1200 nasopharyngeal swabs were collected from healthy 0 to 2 year old children and analyzed by standard microbiological methods. Serotyping was done by SM-PCR and the data were analyzed with R version 2.15.0 (2012-03-30). RESULTS:Streptococcus pneumoniae was detected in 654/1200 children (54.5%) among whom 339 (51.8%) were males. The ages of the study subjects varied from few days to 26 months (mean = 7.1, median = 6, 95% CI [6.8-7.4]). Out of 654 frozen isolates, 377 (54.8%) were able to be re-grown and analyzed. In total, 32 different serogroups/serotypes were detected of which, the most prevalent were 6/(6A/6B/6C/6D) (15.6%), 23F (10.6%), 19F (9.3%), 14 (9%), 19A (5.6%), 23B (4.0%), 25F/38 (3.7%), 18/(18A/18B/18C/18F) (2.9%) and PCR non-typeable (16.4%). Eleven serogroups/serotypes accounting for 57.3% (216/377) were of PCV13 types. Of the 211/377 (56%) isolates tested for drug sensitivity, 23/211 (10.9%), 24/211 (11.4%), 9/211(4.3%) and 148/210 (70.5%) were respectively resistance to oxacillin, chloramphenicol, erythromycin and tetracycline. Thirteen of the oxacillin resistant isolates were additionally multidrug-resistant. No resistance was however detected to gentamycin500?g and to fluoroquinolones (ø Norfloxacin5?g <7mm). Age > 3 months and presence in family of more than one sibling aged < 6 years were significant risk factors for carriage. CONCLUSION:A global rate of 54.5% pneumococcal carriage was detected in this study. The introduced PCV13 vaccine should cover 57.3% (216/377) of circulating serogroups/serotypes, among which were those resistant to antibiotics. Age > 3 months and presence in family of children aged < 6 years were significant factors for pneumococcal carriage. The present data should help understanding post vaccine introduction changes in pneumococcal carriage and infections for better action.
| S-EPMC5245802 | biostudies-literature
Project description:Streptococcus pneumoniae (pneumococcus) frequently colonizes the human nasopharynx and is an important cause of pneumonia, meningitis, sinusitis, and otitis media. The outer cell surface of pneumococcus may assume various degrees of negative charge depending on the polysaccharide capsule, of which more than 90 serotypes have been identified. The negative charge of capsular polysaccharides has been proposed to electrostatically repel pneumococci from phagocytic cells, and avoidance of phagocytosis correlates with higher carriage prevalence. We hypothesized that the surface charge of pneumococcus contributes to its success in nasopharyngeal carriage by modulating resistance to phagocyte-mediated killing. Here, we measured the surface charge (zeta potential) of laboratory-constructed strains that share a genetic background but differ in serotype and of clinical strains that differ in serotype and genetic background. A more negative surface charge correlated with higher resistance to nonopsonic killing by human neutrophils in vitro. In addition, a more negative zeta potential was associated with higher carriage prevalence in human populations before and after the widespread use of the pneumococcal conjugate vaccine PCV7. We also confirmed that capsule is the major determinant of net surface charge in clinical isolates with diverse backgrounds. We noted that exceptions exist to the idea that a higher magnitude of negative charge predicts higher prevalence. The results indicated that zeta potential is strongly influenced by pneumococcal capsule type but is unlikely to be the only important mechanism by which capsule interacts with host.
| S-EPMC3837974 | biostudies-literature
Project description:Streptococcus pneumoniae is a common pathogenic cause of pediatric infections. This study investigated the serotype distribution, antimicrobial susceptibility, and molecular epidemiology of pneumococci before the introduction of conjugate vaccines in Shanghai, China.A total of 284 clinical pneumococcal isolates (270, 5, 4,3, and 2 of which were isolated from sputum, bronchoalveolar lavage fluid, blood, cerebral spinal fluid, and ear secretions, respectively) from children less than 14 years of age who had not been vaccinated with a conjugate vaccine, were collected between January and December in 2013. All isolates were serotyped by multiplex polymerase chain reaction or quellung reactions and antimicrobial susceptibility testing was performed using the broth microdilution method. The molecular epidemiology of S.pneumoniae was analyzed by multilocus sequence typing (MLST).Among the 284 pneumococcal isolates, 19F (33.5%), 19A (14.1%), 23F (12.0%), and 6A (8.8%) were the most common serotypes and the coverage rates of the 7-, 10-, and 13-valent pneumococcal conjugate vaccines (PCV7, PCV10, and PCV13) were 58.6%, 59.4% and 85.1%, respectively. Antimicrobial susceptibility showed that the prevalence rates of S.pneumoniae resistance to penicillin were 11.3% (32/284). Approximately 88.0% (250/284) of the isolates exhibited multi-drug resistance. MLST analysis revealed a high level of diversity, with 65 sequence types (STs) among 267 isolates. Specifically, the four predominant STs were ST271 (24.3%, 65/267), ST320 (11.2%, 30/267), ST81 (9.7%, 26/267), and ST3173 (5.2%, 14/267), which were mainly associated with serotypes 19F, 19A, 23F, and 6A, respectively.The prevalent serotypes among clinical isolates from children were 19F, 19A, 23F, and 6A and these isolates showed high resistance rates to β-lactams and macrolides. The Taiwan19F-14 clone played a predominant role in the dissemination of pneumococcal isolates in Shanghai, China. Therefore, continued and regional surveillance on pneumococcal isolates may be necessary.
| S-EPMC4646667 | biostudies-other
Project description:BackgroundStreptococcus pneumoniae is a major causative agent of severe infections, including sepsis, pneumonia, meningitis, and otitis media, that has since become a major public health concern. In this study, the serotypes distribution of pneumococcal isolates was investigated to predict the efficacy of the 7-valent pneumococcal conjugate vaccine (PCV7) among the Malaysian populations.Methodology/principal findingsA total of 151 clinical isolates were serotyped using multiplex PCR assays. Out of them, there were 21.2% penicillin-resistant, 29.1% penicillin-intermediate, and 49.7% penicillin-susceptible S. pneumoniae strains. Serotypes detected among the Malaysian isolates were 1, 3, 10A, 11A/11D, 12F/12A, 14, 15A, 15B/15C, 16F, 18C/18B/18A/18F, 19A, 19F, 23F, 35B, 35F/47F, 6A/6B, 7C/7B/40, 7F/7A, 9V/9A, and 34. Serotype 19F and 23F were the two most prevalent serotypes detected. Serotypes are highly associated with invasiveness of isolates (p?=?0.001) and penicillin susceptibility (p<0.001). Serotype 19F was observed to have increased resistance against penicillin while serotype 19A has high invasive tendency. Age of patients was an important factor underlying the pneumococcal serotypes (p?=?0.03) and clinical sites of infections (p<0.001). High prevalence of pneumococcal isolates were detected among children <5 years old at nasopharyngeal sites while elderly adults ?60 years old were at increased risk for pneumococcal bacteremia.Conclusion/significanceCurrent study revealed that a number of serotypes, especially those associated with high penicillin resistance, have been formulated in the PCV7. Therefore, the protections expected from the routine use of PCV7 would be encouraging for the Malaysian. However, it is not possible to predict serotypes that might become predominant in the future and hence continued surveillance of circulating serotypes will be needed.
| S-EPMC3095606 | biostudies-literature
Project description:Invasive disease caused by Streptococcus pneumoniae (IPD) is one of the leading causes of morbidity and mortality in young children worldwide. In Argentina, PCV13 was introduced into the childhood immunization programme nationwide in 2012 and PCV7 was available from 2000, but only in the private market. Since 1993 the National IPD Surveillance Programme, consisting of 150 hospitals, has conducted nationwide pneumococcal surveillance in Argentina in children under 6 years of age, as part of the SIREVA II-OPS network. A total of 1713 pneumococcal isolates characterized by serotype (Quellung) and antimicrobial resistance (agar dilution) to ten antibiotics, belonging to three study periods: pre-PCV7 era 1998-1999 (pre-PCV), before the introduction of PCV13 2010-2011 (PCV7) and after the introduction of PCV13 2012-2013 (PCV13), were available for inclusion. Fifty-four serotypes were identified in the entire collection and serotypes 14, 5 and 1 represented 50 % of the isolates. Resistance to penicillin was 34.9 %, cefotaxime 10.6 %, meropenem 4.9 %, cotrimoxazole 45 %, erythromycin 21.5 %, tetracycline 15.4 % and chloramphenicol 0.4 %. All the isolates were susceptible to levofloxacin, rifampin and vancomycin. Of 1713 isolates, 1061 (61.9 %) were non-susceptible to at least one antibiotic and 235(13.7 %) were multidrug resistant. A subset of 413 isolates was randomly selected and whole-genome sequenced as part of Global Pneumococcal Sequencing Project (GPS). The genome data was used to investigate the population structure of S. pneumoniae defining pneumococcal lineages using Global Pneumococcal Sequence Clusters (GPSCs), sequence types (STs) and clonal complexes (CCs), prevalent serotypes and their associated pneumococcal lineages and genomic inference of antimicrobial resistance. The collection showed a great diversity of strains. Among the 413 isolates, 73 known and 36 new STs were identified belonging to 38 CCs and 25 singletons, grouped into 52 GPSCs. Important changes were observed among vaccine types when pre-PCV and PCV13 periods were compared; a significant decrease in serotypes 14, 6B and 19F and a significant increase in 7F and 3. Among non-PCV13 types, serogroup 24 increased from 0 % in pre-PCV to 3.2 % in the PCV13 period. Our analysis showed that 66.1 % (273/413) of the isolates were predicted to be non-susceptible to at least one antibiotic and 11.9 % (49/413) were multidrug resistant. We found an agreement of 100 % when comparing the serotype determined by Quellung and WGS-based serotyping and 98.4 % of agreement in antimicrobial resistance. Continued surveillance of the pneumococcal population is needed to reveal the dynamics of pneumococcal isolates in Argentina in post-PCV13. This article contains data hosted by Microreact.
| S-EPMC8715423 | biostudies-literature
Project description:Infections of Streptococcus pneumoniae in children can be prevented by vaccination; left untreated, they cause high morbidity and fatalities. This study aimed at determining the nasopharyngeal carrier rates, serotype distribution and antimicrobial resistance patterns of S. pneumoniae in healthy Palestinian children under age two prior to the full introduction of the pneumococcal 7-valent conjugate vaccine (PCV7), which was originally introduced into Palestine in a pilot trial in September, 2010. In a cross sectional study, nasopharyngeal specimens were collected from 397 healthy children from different Palestinian districts between the beginning of November 2012 to the end of January 2013. Samples were inoculated into blood agar and suspected colonies were examined by amplifying the pneumococcal-specific autolysin gene using a real-time PCR. Serotypes were identified by a PCR that incorporated different sets of specific primers. Antimicrobial susceptibility was measured by disk diffusion and MIC methods. The resulting carrier rate of Streptococcus pneumoniae was 55.7% (221/397). The main serotypes were PCV7 serotypes 19F (12.2%), 23F (9.0%), 6B (8.6%) and 14 (4%) and PCV13 serotypes 6A (13.6%) and 19A (4.1%). Notably, serotype 6A, not included in the pilot trial (PCV7) vaccine, was the most prevalent. Resistance to more than two drugs was observed for bacteria from 34.1% of the children (72/211) while 22.3% (47/211) carried bacteria were susceptible to all tested antibiotics. All the isolates were sensitive to cefotaxime and vancomycin. Any or all of these might impinge on the type and efficacy of the pneumococcal conjugate vaccines and antibiotics to be used for prevention and treatment of pneumococcal disease in the country.
| S-EPMC3858295 | biostudies-literature
Project description:Background: Streptococcus pneumoniae, a main causative agent associated with invasive and non-invasive infection in elderly population, is a major global health problem. After pneumococcal conjugate vaccines (PCV) and pneumococcal polysaccharide vaccines (PPV) were introduced, the distribution of S. pneumoniae serotypes has changed. There was currently limited data on epidemiology and status of antimicrobial resistance of S. pneumoniae in Shanghai. Objective: To determine the serotype distribution, antimicrobial susceptibility and molecular epidemiology of S. pneumoniae isolated from adults in Shanghai. Method: A total of 75 S. pneumoniae isolates consecutively collected from 2015 through 2017 were serotyped by conventional multiplex-PCR. The antimicrobial susceptibility was determined by broth microdilution method. The multilocus sequence type (MLST) was performed to estimate the molecular epidemiology. Results: The predominant serotypes among the isolates were 19F (20.00%), 3 (16.00%), 23F (9.33%), 14 (8.00%), and19A (5.33%). The prevalence of pneumococcal strains with serotypes targeted by vaccines PCV7, PCV10, PCV13, and PPV23 was 44, 45.33, 66.67, and 80%, respectively. Penicillin non-susceptible S. pneumoniae (PNSSP) accounted for 16% of the isolates examined and resistance to erythromycin, azithromycin, tetracycline, clindamycin, cefaclor and trimethoprim-sulfamethoxazole were found in 92.00, 90.67, 86.67, 81.33, 54.67, and 54.67% of isolates, with most isolates (78.67%) presenting multidrug-resistance. The top three sequence types (STs) were ST271 (17.33%), ST180 (9.33%), and ST81 (8.00%). The international resistance clone complexes Spain23F-1 (n = 4), Netherland3-31 (n = 8), and Taiwan19F-14 (n = 14) were identified. Conclusions: The S. pneumoniae isolates showed high genetic diversity in Shanghai and the prevalence of antimicrobial resistance was also high among S. pneumoniae isolates, most of which were multidrug-resistant. The spread of international resistance clones might contribute to the increase of resistant isolates. The PPV23 could protect against most pneumococcal capsular serotypes causing infection of adults in Shanghai.
| S-EPMC6890718 | biostudies-literature