Thanh V. Phan, Viet Nam
Pasteur Institute of Ho Chi Minh City Micorbiology and ImmunologyPresenter of 2 Presentations
CHARACTERIZATION OF STREPTOCOCCUS PNEUMONIAE FROM INVASIVE PNEUMOCOCCAL DISEASES IN SOUTH VIETNAM, 2008-2018 (ID 1009)
Abstract
Background
Streptococcus pneumoniae is a major cause of meningitis in children under 5 years in Vietnam, yet few data exist on the molecular characteristics of invasive pneumococcal disease (IPD) isolates in our region. This work presents characterization of IPD isolates in south Vietnam by Multilocus Sequence Typing (MLST).
Methods
Forty-three pneumococcal isolates from cases of meningitis (n=36) or sepsis (n=7) in children under five-years of age from 2008-2018 in Vietnam were serotyped by realtime PCR (for a possible 21 serotypes), subject to MLST and analyzed by goeBURST v1.2.1
Results
MLST analysis on 35 isolates to date identified 24 STs. goeBURST analysis identified 12 Clonal Complexes (CC) and 6 singletons. 74% (n=26) of isolates belonged to CCs related to PMEN clones and other multidrug-resistant (MDR) strains. Common CCs were CC90 (Spain6B-2) and CC236 (Taiwan19F-14) with 6 isolates each, followed by CC320/271 and CC63 (Sweden15A-25) with 5 and 4 isolates, respectively. Serotypes 6A/B, 14, and 19F were common and these belonged to 6, 4, 3 difference CCs, respectively.
Conclusions
There was a high diversity of pneumococcal clones associated with meningitis and sepsis in young children in south Vietnam. Most of the isolates belonged to PMEN clones or MDR strains.
IMMUNOGENICITY OF A SINGLE DOSE OF PCV10 OR PCV13 AT 2 MONTHS OF AGE IN VIETNAM (ID 1007)
Abstract
Background
A 1+1 pneumococcal conjugate vaccine (PCV) schedule would increase its affordability for low and middle-income countries. The Vietnam Pneumococcal Trial II includes infants randomised to receive a 1+1 schedule of PCV10 or PCV13 at 2 and 12 months of age. This study measured the immunogenicity of a single dose of either PCV given at 2 months of age.
Methods
Serotype-specific IgG was measured at 3 and 12 months of age in PCV-vaccinated and unvaccinated controls using a WHO ELISA method.
Results
At 3 months, both vaccinated groups had higher antibody levels than controls for 7/10 serotypes (all except 6B, 14, 23F). The PCV10 group had higher antibody levels than the PCV13 group for 5/10 serotypes. Similar results were seen at 12 months, with higher antibody levels for all serotypes in the PCV10 group and 8/10 serotypes (all except 6V, 23F) in the PCV13 group compared with controls and higher antibody levels in the PCV10 than the PCV13 group for 7/10 serotypes.
Conclusions
A single dose of PCV in infancy is immunogenic and likely to provide some direct protection until the time of the booster dose. There may be a difference in the degree of protection offered by different PCVs.
Author Of 8 Presentations
IMMUNOGENICITY OF A SINGLE DOSE OF PCV10 GIVEN AT 18 MONTHS OF AGE AND IMPACT ON NASOPHARYNGEAL CARRIAGE IN VIETNAMESE CHILDREN (ID 735)
- Rachel A. Marimla, Australia
- Beth Temple, Australia
- Thi Trang Dai Vo, Viet Nam
- Thanh V. Phan, Viet Nam
- Trong Toan Nguyen, Viet Nam
- Leena Spry, Australia
- Monica L. Nation, Australia
- Belinda D. Ortika, Australia
- Doan Y. Uyen, Viet Nam
- Cattram D. Nguyen, Australia
- Kathryn Bright, Australia
- Anne Balloch, Australia
- Huu T. Ngoc, Viet Nam
- Kim E. Mulholland, Australia
- Catherine Satzke, Australia
- Paul V. Licciardi, Australia
COMPARISON OF A 2+1 AND 3+0 SCHEDULE OF PCV10 IN VIETNAM (ID 1035)
- Beth Temple, Australia
- Paul V. Licciardi, Australia
- Vo Thi Trang Dai, Viet Nam
- Trong Toan Nguyen, Viet Nam
- Doan Y. Uyen, Viet Nam
- Cattram D. Nguyen, Australia
- Thanh V. Phan, Viet Nam
- Hoan Thi Pham, Viet Nam
- Kathryn Bright, Australia
- Rachel A. Marimla, Australia
- Monica L. Nation, Australia
- Belinda D. Ortika, Australia
- Catherine Satzke, Australia
- Heidi Smith-Vaughan, Australia
- Anne Balloch, Australia
- Tran Ngoc Huu, Viet Nam
- Edward K. Mulholland,
ANTIBIOTIC SUSCEPTIBILITY OF STREPTOCOCCUS PNEUMONIAE IN SOUTHERN VIETNAM (ID 855)
Abstract
Background
Streptococcus pneumoniae is a bacterial pathogen responsible for severe infections in children, especially meningitis. The emergence of multidrug-resistant S.pneumoniae, likely due to indiscriminate antibiotic use, is a serious public health problem in Vietnam. The aim of this study was to survey antimicrobial susceptibility of invasive S. pneumoniae isolates.
Methods
Twenty-five isolates from children <5 years old with meningitis in Southern Vietnam from 2012-2018 were serotyped by realtime PCR and Quellung reaction. Antimicrobial susceptibility was determined by Kirby Bauer (erythromycin, clindamycin, tetracycline, trimethoprim-sulfamethoxazole, chloramphenicol, levofloxacin, rifampin, vancomycin) and MIC methods (penicillin and ceftriaxone) with the data interpreted by CLSI, 2018.
Results
All pneumococcal isolates were non-susceptible to penicillin, erythromycin, clindamycin, and tetracycline, with 92%, 48%, and 20% non-susceptible to trimethoprim-sulfamethoxazole, ceftriaxone, and chloramphenicol, respectively. All isolates were susceptible to levofloxacin, rifampin, and vancomycin. All isolates were non-susceptible to multiple antibiotic classes (at least three classes of antibiotic) with serotype 6A and 6B isolates non-susceptible to most antibiotics tested. Furthermore, higher resistance rates were observed in this study compared to Southern Vietnam in previous periods.
Conclusions
Antibiotic resistance of invasive S. pneumoniae isolates from pediatric patients with meningitis in Southern Vietnam is alarmingly high. Strategies to combat pneumococcal antibiotic resistance are urgently needed.
INCREASED PCV10 IMMUNOGENICITY FOLLOWING A TWO-DOSE PRIMARY SERIES SEPARATED BY 4 MONTHS COMPARED WITH 2 MONTHS IN VIETNAMESE INFANTS (ID 963)
- Paul V. Licciardi, Australia
- Beth Temple, Australia
- Dai V. Trang, Australia
- Trong Toan Nguyen, Viet Nam
- Uyen Y. Doan, Viet Nam
- Cattram D. Nguyen, Australia
- Thanh V. Phan, Viet Nam
- Kathryn Bright, Australia
- Rachel A. Marimla, Australia
- Anne Balloch, Australia
- Tran Ngoc Huu, Viet Nam
- Kim E. Mulholland, Australia
BACTERIAL MENINGITIS SURVEILLANCE OF CHILDREN UNDER 5 YEARS OF AGE IN SOUTHERN – VIET NAM, 2018-2019 (ID 313)
Abstract
Background
In Vietnam, the Invasive Bacterial Vaccine Preventable Diseases (IB-VPD) Surveillance network of World Health Organization which identifies major pathogens causing bacterial meningitis has been implemented since 2012. This program utilizes realtime PCR for detection of Streptococcus pneumoniae (Spn), Neisseria meningitidis (Nm) and Haemophilus influenzae (Hi) in children under 5 years of age suspected for bacterial meningitis. This work presents the positive rate and serotypes distribution of Spn from this program between 2018 and 2019.
Methods
540 cerebrospinal fluid (CSF) specimens of probable bacterial meningitis cases from 1 month to 59 months old were collected for identification of Spn, Nm and Hi by triplex direct rt-PCR. Positive samples for Spn were serotyped for 21 serotypes.
Results
Total positivity rate of three pathogens was 6.5%, among which Spn was predominant (94.3%, n= 33), following by Nm (5.7%, n=2), and there was no Hi detected. PCV13-types account for 94.0%, of which 6A/B was the most prevalent serotype (54.5%, n=18).
Conclusions
Spn was the most common cause of pediatric bacterial meningitis in Southern Vietnam from 2018-2019. Majority of serotypes found are included in pneumococcal conjugate vaccines, which are not yet introduced in the national immunization schedule in Vietnam.
IMMUNOGENICITY OF A SINGLE DOSE OF PCV10 OR PCV13 AT 2 MONTHS OF AGE IN VIETNAM (ID 1007)
Abstract
Background
A 1+1 pneumococcal conjugate vaccine (PCV) schedule would increase its affordability for low and middle-income countries. The Vietnam Pneumococcal Trial II includes infants randomised to receive a 1+1 schedule of PCV10 or PCV13 at 2 and 12 months of age. This study measured the immunogenicity of a single dose of either PCV given at 2 months of age.
Methods
Serotype-specific IgG was measured at 3 and 12 months of age in PCV-vaccinated and unvaccinated controls using a WHO ELISA method.
Results
At 3 months, both vaccinated groups had higher antibody levels than controls for 7/10 serotypes (all except 6B, 14, 23F). The PCV10 group had higher antibody levels than the PCV13 group for 5/10 serotypes. Similar results were seen at 12 months, with higher antibody levels for all serotypes in the PCV10 group and 8/10 serotypes (all except 6V, 23F) in the PCV13 group compared with controls and higher antibody levels in the PCV10 than the PCV13 group for 7/10 serotypes.
Conclusions
A single dose of PCV in infancy is immunogenic and likely to provide some direct protection until the time of the booster dose. There may be a difference in the degree of protection offered by different PCVs.
IMPACT OF A SINGLE DOSE OF PCV10 OR PCV13 ON NASOPHARYNGEAL PNEUMOCOCCAL CARRIAGE IN VIETNAMESE CHILDREN DURING THE FIRST YEAR OF LIFE (ID 696)
- Hoan Thi Pham, Viet Nam
- Beth Temple, Australia
- Thi Trang Dai Vo, Viet Nam
- Thanh V. Phan, Viet Nam
- Loc Thuy Ho Nguyen, Viet Nam
- Anh H.V Nguyen,
- Belinda D. Ortika, Australia
- Kathryn Bright, Australia
- Catherine Satzke, Australia
- Nevio D. Sarmento, Timor-Leste
- Jemima Beissbarth, Australia
- Heidi Smith-Vaughan, Australia
- Thuong V. Nguyen, Viet Nam
- Kim E. Mulholland, Australia
Abstract
Background
Reduced-dose schedules of pneumococcal conjugate vaccine (PCV) could increase the accessibility and use of PCV in low and middle-income countries.
Methods
Groups within the Vietnam Pneumococcal Trial II receive PCV10 and PCV13 in a 1+1 schedule at 2 and 12 months of age, or no vaccine. Nasopharyngeal swabs were collected at 6 and 12 months of age to show the impact of the 2-month dose on pneumococcal carriage.
Results
Based on analysis to date of 1152 of 3200 swabs, vaccine-type carriage was low. In unvaccinated participants, PCV10 and PCV13-type carriage were 5.1% and 10.4% at 6 months, and 8.3% and 12.0% at 12 months, respectively. A dose of PCV10 transiently reduced vaccine-type carriage at 6 months of age (3/178 [1.7%] versus 18/355 [5.1%]).
Conclusions
With the exception of the PCV10 group at 6 months of age, both vaccine-type and non-vaccine-type carriage rates were similar among PCV10-vaccinated participants, PCV13-vaccinated participants and unvaccinated controls at 6 and 12 months of age. Based on preliminary data, a single dose of PCV at 2 months of age does not appear to reduce pneumococcal carriage during the first year of life in this population.
CHARACTERIZATION OF STREPTOCOCCUS PNEUMONIAE FROM INVASIVE PNEUMOCOCCAL DISEASES IN SOUTH VIETNAM, 2008-2018 (ID 1009)
Abstract
Background
Streptococcus pneumoniae is a major cause of meningitis in children under 5 years in Vietnam, yet few data exist on the molecular characteristics of invasive pneumococcal disease (IPD) isolates in our region. This work presents characterization of IPD isolates in south Vietnam by Multilocus Sequence Typing (MLST).
Methods
Forty-three pneumococcal isolates from cases of meningitis (n=36) or sepsis (n=7) in children under five-years of age from 2008-2018 in Vietnam were serotyped by realtime PCR (for a possible 21 serotypes), subject to MLST and analyzed by goeBURST v1.2.1
Results
MLST analysis on 35 isolates to date identified 24 STs. goeBURST analysis identified 12 Clonal Complexes (CC) and 6 singletons. 74% (n=26) of isolates belonged to CCs related to PMEN clones and other multidrug-resistant (MDR) strains. Common CCs were CC90 (Spain6B-2) and CC236 (Taiwan19F-14) with 6 isolates each, followed by CC320/271 and CC63 (Sweden15A-25) with 5 and 4 isolates, respectively. Serotypes 6A/B, 14, and 19F were common and these belonged to 6, 4, 3 difference CCs, respectively.
Conclusions
There was a high diversity of pneumococcal clones associated with meningitis and sepsis in young children in south Vietnam. Most of the isolates belonged to PMEN clones or MDR strains.