Background

Pneumococcal serotype identification is essential to monitor pneumococcal vaccine effectiveness and serotype replacement. We compared four different methods: PCRSeqTyping, Quellung reaction, Single-step Multiplex-PCR Assay and S. PneumoStrip of Streptococcus pneumoniae serotyping.

Methods

A double blind study was carried out in Donostia University Hospital (northern Spain) where four different techniques were used to compare the serotyping of 18 pneumococcal strains obtained from clinical specimens. PCRSeqTyping to detect 91 different serotypes, Quellung reaction as the Gold Standard, Single-step Multiplex-PCR Assay able to differentiate 92 serotypes and S. PneumoStrip for the identification of 76 pneumococcal serotypes , 42 individually and 34 in pairs.

Results

A 100% correlation of PCRSeqTyping results was observed with PneumoStrip results and Single-step Multiplex-PCR Assay and 15 (83.3%) by Quellung reaction. The quickest technique was PneumoStrip followed by Single-Step multiplex PCR Assay and PCRSeqTyping. Quellung reaction was the slowest technique.

Conclusions

PneumoStrip was an accurate and rapid technique with high reproducibility, as was PCRSeqTyping. Single-step Multiplex-PCR Assay was also a good technique for S. pneumoniae serotyping which does not require culturing the samples unlike PneumoStrip or Quellung reaction. Quellung reaction was also not totally reliable due to its subjective nature.

Background

In Streptococcus pneumoniae (Spn), the Macrolide Genetic Assembly (Mega) provides macrolide antibiotic resistance via the efflux pump Mef(E) and the ribosomal protection protein Mel. This resistance has previously been assumed to confer traditional resistance. Heteroresistance is commonly missed during traditional clinical resistance screens, and is highly concerning as resistant sub-populations can persist despite treatment.

Methods

Spn strains containing the Mega element were screened via Etesting and Population Analysis Profiling. In addition to screening wildtype strains, strains with deletions of the 5’UTR of Mef(E) were also queried.

Results

All wildtype Mega-containing Spn strains screened displayed heteroresistance (>eight fold range in MICs) to Mef(E)/Mel-inducing macrolides, but not to non-Mef(E)/Mel-inducing Macrolides or other classes of antibiotics. When macrolide induction uniformly increased mef(E)/mel expression, heteroresistance was eliminated. A deletion of the 5’UTR of mef(E) resulted in a mutant deficient in induction as well as heteroresistance. Only the mef(E)L leader peptide sequence of the 5’UTR is required for induction and heteroresistance.

Conclusions

This study finds that inducibility and heteroresistance are linked for macrolide resistance conferred by the Mega element independent of insertion class. Stochastic variation or epigenetics affecting mef(E)/mel expression inside a population of Spn are possible mechanisms for heteroresistance.

Background

Multidrug resistance in Streptococcus pneumoniae (Spn) has been increasingly attributed to dissemination of integrative and conjugative elements (ICEs), such as Tn2009 (23.5kb). The mechanism for Spn ICE dissemination has not been defined.

Methods

Recombination frequency (rF) for Tn2009 was investigated utilizing in vitro transformation or an ex vivo nasopharyngeal biofilm bioreactor. Recombinant lineage and extracellular DNA (eDNA) concentrations were determined by serotype-specific qPCR. Whole genome sequencing (WGS) identified putative junctions for Tn2009 recombination.

Results

In vitro transformation yielded no Tn2009-containing D39 recombinants (rF<10^-9) while mutation-mediated streptomycin resistance was obtained (rF 10^-6). However, in the bioreactor, Tn2009 transference from donor GA16833^Tet/Ery (ST19F) to recipient D39^Str (ST2) generated >90% D39^Tet/Str recombinants with variably sized donor DNA fragments encompassing intact Tn2009 (rF 10^-4), indicating varied recombination junctions. Tn2009 transference was prevented by DNaseI addition (rF<10^-7). D39 competence mutants (ΔcomC/D/E) with GA16833 yielded reduced rFs (10^-8-10^-6) and nearly 100% ST19F recombinants acquiring Str resistance. Similar bacterial densities and eDNA concentrations from each strain were detected. D39ΔcomC with GA16833ΔcomC yielded no recombinants (rF<10^-7).

Conclusions

Efficient Tn2009 dissemination among Spn strains occurs in an ex vivo nasopharyngeal biofilm and requires recipient competence development. Further, there is a com-mediated dominance for a specific Spn strain to acquire resistance.

Background

In July 2011, the 13- valent pneumococcal conjugate vaccine (PCV 13) was introduced into the routine immunization program in Cameroon.After the introduction of this vaccine, post-vaccine surveillance continued to monitor vaccine effectiveness and detect the emergence of new strains

We describe the pneumococcal serotypes that circulated after the introduction of PCV 13.

Methods

Retrospective review data from sentinel laboratory-based surveillance system from 2011 to 2018. Lumbar puncture was performed on children under five years admitted with suspected meningitis at the paediatric hospital in Yaoundé. Cerebrospinal fluid (CSF) specimens were tested by Gram stain, culture, latex agglutination and/ or Polymerase Chain Reaction (PCR). Serotyping/grouping, and/or whole genome sequencing were performed on Streptococcus pneumoniae isolates

Results

Among 8108 CSF specimens tested, 116 cases of meningitis were confirmed .89(76.7%) were positive for Streptococcus pneumoniae. PCR serotyping identified 19(39.5%) and 29(60.4%) S. pneumoniae PCV13 and non-PCV13 serotypes respectively. The most frequent non vaccine pneumococcal serotype was serotype 2 (13.7%) and the most frequent vaccine pneumococcal serotypes were 6A/ 6B (26%)

Conclusions

PCV 13 serotypes still remain in circulation . There is need for continuous surveillance and monitoring how vaccines can affect the evolution of strains over a long period of time

Background

The number of multidrug resistant Streptococcus pneumoniae or pneumococcus isolates have been increasing worldwide, including Cotrimoxazole-resistant isolates. Different pattern of folA and folP polymorphisms from cotrimoxazole-resistant pneumococcus have been previously reported. These genetic variations play important role in cotrimoxazole resistance mechanism. This study was conducted to characterize folA and folP gene mutation variation in cotrimoxazole-resistant pneumococcus isolates in Indonesia.

Methods

We measured cotrimoxazole MIC value from 78 pneumococcus isolates isolated from nasopharyngeal carriage in Indonesia population. Nucleotide sequences of folA and folP translated into amino acid sequences and analysed for genetic polymorphisms.

Results

We found 82% (58/71) of pneumococcus isolates were non-susceptible to cotrimoxazole (MICs ≥4 µg/ml). Ile-100-Leu substitution in dihydrofolate reductase (encoded by folA) sequence and 1-2 amino acids insertion in dihydropteroate synthase (encoded by folP) sequence were found in most cotrimoxazole-resistant isolates. Mutation on folA sequence and both on folA and folP sequences have significant impact to cotrimoxazole resistance level (p<0,05), whereas folP mutations does not have significant effect (p>0,05).

Conclusions

Most mutation variants found in cotrimoxazole-resistant pneumococcus in Indonesia were quite similar to other variants that have been reported in other regions. Mutations in folA sequences have more effect on increasing cotrimoxazole resistance compared to mutation in folP sequences.

Background

Macrolide resistance of Streptococcus pneumoniae has already increased in worldwide. In Asia, >70% of clinical S. pneumoniae isolates was reported as erythromycin resistant. ErmB and mefA genes existence plays a role in resistance mechanism by modification of drug binding site and active efflux of the cell. This study is aimed to analyze macrolide resistant genes (ermB and mefA) associated with prevalence of non-susceptible erythromycin S. pneumoniae isolates in Indonesia.

Methods

Seventy isolates of S. pneumoniae were processed for antimicrobial susceptibility testing according to CLSI. The ermB and mefA genes were detected using duplex PCR. Association between these genes and erythromycin resistance rate was analyzed using Fisher test.

Results

A total of 47 (67%) isolates were nonsusceptible to erythromycin. ErmB was detected in 24 (34.2%) isolates and mefA was detected in 50 (71.4%) isolates. Isolates having both ermB and mefA were 34 (48.5%) isolates. There was association between erythromycin resistance with existence of mefA gene (P < 0.001), ermB (P = 0,045) and both (P = 0,036). The most common resistance isolates were serotype 19F (38,2%) and 23F (31,9%).

Conclusions

The existence of mefA and ermB seems to be associated with erythromycin non-susceptible of S. pneumoniae where mefA is the most associated to resistance.

Background

Pneumococcal capsules are important in pathogenesis and vaccine development. Serotype 24F capsule consists of a hexasaccharide repeating unit with arabinitol (WO 2019/050815 AI). Here, we describe the discovery of a novel serotype (“24X”) within serogroup 24.

Methods

Serological properties of pneumococcal isolates were studied using Quellung. Serotypes 24F, 24A, 24B and 24X were subjected to whole genome sequencing (WGS). The capsular polysaccharide (CPS) structures were elucidated by NMR and GC-MS.

Results

Multiple pneumococcal isolates from several countries reacted with both factor sera 24d and 24e. Since this reaction pattern has not been reported and is unique, the isolates were provisionally labelled to be serotype “24X.” Genetic studies of cps loci could not distinguish 24X from 24F or 24B. Chemical structure studies of serogroup 24 members showed that 24B CPS is like 24F except for having ribitol instead of arabinitol, 24X CPS contains both repeat units of 24F and 24B. These findings could explain their reactivity with factor sera 24d and 24e.

Conclusions

The 24X capsule has a distinct serology and repeating unit structure, which qualify it as a new serotype. According to the Danish naming system, 24X was named serotype 24C. Correlation of cps loci with the capsule structure is under investigation.

Background

We examined the serotype distribution patterns of pneumococcal meningitis in the following countries: Ukraine, Belarus, Azerbaijan, Armenia, Georgia and Uzbekistan. The study was performed within the program for Invasive Bacterial Diseases Sentinel Surveillance implemented in the region by WHO Regional Office for Europe.

Methods

Cerebrospinal fluid samples (CSFs) were collected from patients with suspected meningitis at sentinel hospitals within 2007 – 2017. S. pneumoniae serogroups/serotypes in positive CSFs were determined using qPCR and mPCR. Overall, 2980 CSFs from patients aged under 5 years were tested.

Results

173 (5, 8%) CSFs were positive for S. pneumoniae. Pneumococcal serotypes/serogroups were determined in 77,5% (134) of positive CSFs, 22,5% were not-typeable. 27 serotypes/serogroups were identified. Serotypes 6A/B (17,3%), 14 (15,6%), 19F (13%), 23F (5,8%), 18A/B/C (4,6%), were the most prevalent, followed by others with a prevalence of 2% and less (9V/9A, 4, 6C/6D, 24A/B/F,19A, 5, 3, 1, 23A, 20, 2, 13, 31, 8, 7F/7A, 7C/7B/40, 22F/22A, 21, 15B/15C, 12F/12A/12B/44/46, 11A/11D, 16F).

Conclusions

The proportion of vaccine serotypes amounts to 60, 5% for PCV10 and 64,1% for PCV13, suggesting that the introduction of the conjugate vaccine is feasible and justifiable. Ongoing surveillance is needed to monitor the dynamics of serotype distribution following the introduction of PCVs.

Background

No recent data is available on the serotypes or antimicrobial susceptibility of S.pneumoniae isolated from nasopharyngeal carriage (NC) or invasive pneumococcal disease (IPD) in Egypt. We aimed to identify the serotypes and antimicrobial susceptibility testing (AST) of S.pneumoniae NC and IPD of Egyptian children younger than 5 years.

Methods

In 2 successive winter seasons (2016-2017), we enrolled 334 children less than 5 years, excluding those with signs of infection, antibiotic intake or hospitalization in the preceding month. Additionally, we studied 32 S.pneumoniae isolates from IPD, identified during the study duration.

We tested for S.pneumoniae by culture and PCR from NC and IPD. Serotyping was performed by sequential multiplex PCR for all positive samples. AST was done to S.pneumoniae isolates by Vitek-2™.

Results

PCR was positive from 65% of swabs compared to 32.9% by culture. The most common five serotypes were serotypes 1, 6 and 19 F, 5 and 18ABC. From IPD, the commonest serotypes were 1, 18ABC and 6.

The AST of NP isolates revealed low susceptibility rates to all antimicrobials except for vancomycin, levofloxacin and clindamycin. Isolates from clinical specimens, however were more susceptible.

Conclusions

Serotypes 1, 18ABC and 6 caused NC and IPD, and had low antimicrobial susceptibility.

Background

Spread of MDR-S. pneumoniae requires regular monitoring of the resistance level worldwide. Emerging fluoroquinolone resistant pneumococci cause concern.

Methods

MDR-pneumococci (n=478;22%) were collected from nasopharyngeal pediatric pneumococcal collection from Russia, in 2010-2018. Susceptibility testing to ten antimicrobial groups was performed using the broth microdilution method (Sensititre). WGS was performed on the Illumina HiSeq-2500 platform.

Results

The most common resistance (R) profile among MDR-pneumococci was nonsusceptibility to erythromycin/clindamycin/tetracycline/trimethoprim-sulfamethoxazole +/-penicillin, which was determined in 32.4% (n=155) or 23.4% (n=112) isolates, respectively. Moreover, six isolates possessed resistance to fluoroquinolones. A total of 25 different serotypes were identified. One or more isolates of each MDR-serotypes were selected for the WGS.
39 MDR-isolates with levofloxacin MICs<2 mg/L had no mutations in the quinolone-resistance determining regions. Two levofloxacin/moxifloxacin-R 23F/ST81 pneumococci (MIC 8 and 2 mg/L) had mutations in parC(D83N,K137N)/gyrA(S81F)/parE(I460V); susceptible to moxifloxacin 19F/ST8099 and 31/ST2992 (levofloxacin MIC 4 and 8 mg/L) had mutations in parC(D83Y)/parE(I460V). It should be noted, that two levofloxacin/moxifloxacin-R 19F/ST162 and 23F/ST102 isolates (MIC 8 and 1 mg/L) had not typical mutations, and it can be associated with antibiotic efflux. Previously described amino acid substitutions in the gyrB have no been identified.

Conclusions

Genomic surveillance could be a useful tool for monitoring of antibiotic resistance formation.

Background

Reduced amounts of the essential penicillin-binding protein 2x (PBP2x) were noted in two cefotaxime resistant S. pneumoniae laboratory mutants C405 and C606 derived independently from the sensitive strain R6. These mutants contain two or four mutations, respectively, in the transpeptidase domain of PBP2x. Furthermore, they carry a mutation in ciaH encoding the histidine protein kinase of the two-component system CiaRH, resulting in enhanced CiaR-mediated gene expression.

Methods

To characterize the effect of each of these mutations, beta-galactosidase assays, fluorescence microscopy and depletion studies were performed on mutants and derivatives thereof. Susceptibility to beta-lactam antibiotics was determined by agar dilution method.

Results

The transcription of pbp2x in both mutants is not affected, thus the reduced amount of PBP2x is likely to be due to degradation of the protein. We tested the cell wall associated serine protease HtrA, which is part of the CiaRH regulon, as a potential candidate. Deletion of htrA or introduction of a mutation in the active site of HtrA in C405 and C606 lead to wild type amounts of PBP2x. Depletion studies of the PBP2x_C405 variant and localization studies of GFP-PBP2x_C405 fusion-protein confirmed that HtrA degrades PBP2x in C405 and C606.

Conclusions

Our results show that HtrA targets altered PBP2x.

Background

Pneumococcal nasopharyngeal colonization is increasingly used as a surrogate marker for disease risk, thus accurate detection is crucial. However, it is not known if host age affects the colonization niche and, consequently, pneumococcal (Spn) detection in adults. Using the Experimental Human Pneumococcal Challenge (EHPC) model, we investigated if detection of pneumococcal carriage in the nose and oropharynx changes with increasing age.

Methods

Healthy adults (n=112) were intranasally inoculated with Spn6B and monitored for a month. Volunteers were split into young 18-55yrs (n=57) and older adults >55yrs (n=55). Colonization was determined by lytA and 6AB-specific multiplex qPCR assay in both raw and culture-enriched nasal wash (NW) and oropharyngeal swab (OPS). Colonization status was compared at 2, 7 and 14 days post-inoculation in both niches.

Results

We observed that the Spn6B colonization rate decreases with ageing in both NW (young 70.2%, older 50.9%) and OPS (young 64.9%, older 34.5%). Pneumococcal presence is higher in NW than OPS in both groups (young 70.2%-64.9% and older 50.9%-34.5%).

Conclusions

Pneumococcal presence in the nasopharynx is age-dependent. The nose, as assessed by NW sampling, seems to be the best niche for detection of pneumococcal colonization in adults, regardless of their age.

Background

After introduction of PCV-13 in the USA in 2010, emergence of replacement serotypes occurred. From our ongoing 14-year prospective study we report Streptococcus pneumoniae (Spn) strains colonizing the nasopharynx (NP) of children based on serotype, sequence type (ST) and antibiotic susceptibility along with otopathogens, Haemophilus influenzae (Hi) and Moraxella catarrhalis (Mcat) for years 2015-2019.

Methods

2059 visits (1528 healthy, 393 AOM and 138 AOM-follow-up visits) from 589 children, ages 6-36 months were included. 495 middle-ear fluid (MEF) were obtained during AOM by tympanocentesis.

Results

In the NP we isolated Mcat (39%) >Spn (32%) >Hi (12%) at healthy visits and Mcat=Spn (53%) >Hi (36%) at onset of AOM. MEF culture results were Hi (35%) >Spn (24%) >Mcat (15%) Correlation of NP and MEF isolates at onset of AOM was poor. In the NP, serotype 35B (18.3%/20.6%) >23B (17.9%/9.1%)>15B/C (10.6%/12%) predominated at healthy/at onset of AOM. 35B (22.4%) was the most common serotype isolated from MEF. ST558 and ST199 were the most common sequence types in healthy and AOM visits. Penicillin and erythromycin antibiotic-nonsusceptibility were most frequent among Spn isolates

Conclusions

Dynamic changes in pneumococcal prevalence and serotypes colonizing the NP and causing AOM occurred in 2015-2019.

Background

We investigated impact of culture-enrichment on the rank of serotypes when detected quantitatively in nasopharyngeal samples from toddlers co-carrying multiple pneumococcal strains.

Methods

Pneumococcal serotypes were detected in nasopharyngeal swabs (collected in a cross-sectional study from children aged <5 years) using conventional culture method followed by testing in serotype-specific qPCRs the DNA extracted from all bacterial growth harvested from culture-plates. Next, we quantified with qPCR serotypes in uncultured samples and compared serotype ranks before and after culture-enrichment.

Results

Co-presence of multiple serotypes has been detected in 37 (5.6%) of 658 nasopharyngeal samples. The number of serotype carriage events detected by any method in these 37 samples was 83 (2-5 per sample) while the number of strains cultured was 42 (1-2 per sample). For the majority of samples (n=27 or 73%) the serotype ranks in uncultured and culture-enriched samples matched. A shift in serotype rank was observed in 11% of the samples (4 of 37) whereas in another 16% (6 of 37) the discordance was due to fewer serotypes detected in uncultured samples.

Conclusions

While increasing sensitivity of carriage detection, culture-enrichment has limited impact on the rank of serotypes present in nasopharyngeal swabs and can therefore be used to provide insight into co-carriage dynamics.

Background

Pneumococcal carriage influences population-wide strain dynamics, but limited data exist on serotype-specific temporal carriage patterns among PCV-vaccinated West African infants.

Methods

Pneumococcus was cultured from nasopharyngeal swabs (n=1, 595) collected from 102 PCV7-exposed infants followed up from birth to 12 months. Serotyping was performed by whole genome sequencing and sweep-latex agglutination. Parametric survival models with constant hazard rates were fitted to estimate carriage dynamics (duration, clearance and acquisition).

Results

The infants were naturally colonised with 60 pneumococcal serotypes with a mean of 7 (range:2-11) serotypes per infant. Carriage dynamics estimates for serotypes 5, 7F, 39, 9A, and 12F are provided here for the first time in infants. There was no correlation between time to first acquisition and carriage duration (ρ=0.06, P=0.709). Serotype prevalence showed a weak correlation with initial acquisition (ρ=0.07, P=0.706), carriage duration (ρ=0.219, P=0.194), and reacquisition times (ρ=0.09, P=0.730). Onset of initial acquisition was longer than the time taken to reacquire serotypes (median: 136.23 vs 26.15 days, P=7.63×10-6). Overall, serotype-specific carriage durations after initial acquisition and reacquisition were significantly different (P=0.020), varying by serotype.

Conclusions

Pneumococcal carriage dynamics among Gambian infants are complex and highly variable by serotype which may have important implications for transmission and invasive disease.

Background

Invasive Pneumococcal Disease (IPDs) is a leading cause of morbidity and mortality. In Colombia, the 7-valent pneumococcal conjugate vaccine was introduced in 2006 and replaced in 2011 by 10-valent. However, the number of S.pneumoniae serotype-19A causing IPDs in Bogotá has considerably increased in the last years. Thus, we characterized all S.pneumoniae serotype-19A isolates received from the Public Health Laboratory Network of Bogotá (PHLNB) in 2017, after Pneumococcal Conjugate Vaccine implementation.

Methods

This study was conducted with all S.pneumoniae serotype-19A isolates received in 2017 from PHLNB. Standard laboratory methods were performed for pneumococcal culture. Identification and antimicrobial susceptibility/resistance were done by automated method (VITEK-BioMérieux). Serotyping results (Quellung Reaction) were received by feedback of the Colombian National Institute of Health. Statistical analysis: Excel/SPSS.

Results

In 2017, 227 S.pneumoniae IPD-isolates were received from PHLNB. The most prevalent serotypes were 19A/3/23A/9N/6C/14/35B. Serotype-19A accounted for 20.3% (46/227) of IPD-isolates. Twenty-two (47.8%) children <5 years were affected by this serotype in 2017 with Pneumonia (39.1%) and Sepsis (34.9%). All 46 serotype-19A were susceptible to vancomycin and chloramphenicol, while reduced susceptibility and/or resistance was observed for erythromycin (100%), penicillin (65.2%) and Trimetoprim-Sulfametoxazol (58.7%).

Conclusions

These results evidence the predominant emergency of S.pneumoniae multidrug-resistant serotype-19A, among children <5 years in Bogotá-Colombia.

Background

The PCV13 vaccine was introduced in 2015. We determined serotypes and antibiotic resistance of pneumococcal strains isolated from children with IPD in Lima, Peru after PCV13 introduction.

Methods

This was a passive surveillance study (Nov-2016 to Dic-2019) in 6 hospitals and 5 private laboratories in Lima, in children <18 years with IPD. Pneumococcus was confirmed by microbiological and lytA gene amplification. Antibiotic resistance was performed by E-test and disc-diffusion. Strains were serotyped by Sequential-multiplex-PCR.

Results

85 pneumococcus strains were isolated from children with IPD. The most prevalent diagnosis was pneumonia 61% and meningitis 19%. Age range was among 2 months and 13 years. 46% were <2 years, 86% were <5 years. 51% were female. High levels of antibiotic resistance to azithromycin 79%, cotrimoxazole 75%, tetracycline 70% and clindamycin 68% was observed. The resistance among Meningeal and Non-meningeal isolates was 40% and 12% for Penicillin; 0% and 1% for ceftriaxone. More common serotype/serogroup were 19A(65.5%), 24(24A/24B/24F)(32.8%), 6(6A/6B/6C/6D)(8.6%) and 15B/15C(6.9%). 19A is decreasing loosely throughout the years [2017(50%), 2018(45%) and 2019 (33%)]. serogroup 24A/24B/24F was the emerging serotype post-PCV13.

Conclusions

Serotype 19A remain circulating in Lima. Serogroup 24A/24B/24F is emerging post-PCV13 introduction. High levels of antibiotic resistance is observed compared to previous studies in Lima

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 (Spain^6B-2) and CC236 (Taiwan^19F-14) with 6 isolates each, followed by CC320/271 and CC63 (Sweden^15A-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.

Background

Antimicrobial resistance of S. pneumoniae is described worldwide and is increasing. The situation of this resistance in some countries in Africa like Cote d'Ivoire remains unclear.We aim to describe the resistance profiles of S. pneumoniae strains against antibiotics tested in a reference laboratory in Abidjan.

Methods

We conducted secondary data analysis and extracted data from Laboratory database containing all the results of the antibiograms performed at Pasteur Institute of Cote d'Ivoire from 2009-2018. The analysis was done using Epi info software version 7. 2. and exported to Microsoft Excel removing duplicates and presented the results into frequencies and proportions.

Results

The analysis involved 150 human strains isolated from 59. 3% of cerebrospinal fluid cases. The age group 0 to 2 years was the highest 52. 8%. Concerning the resistance of antibiotic, 27. 02% showing decreased susceptibility to beta-lactam antibiotics and 23. 2% showing resistance to Gentamycin. For Erythromycin and Levofloxacin, the prevalence of bacteria resistant to these two antibiotics was 17.2% and 13. 6% respectively.

Conclusions

Antibiotic resistance of S pneumoniae strains exists and it is important in Côte d'Ivoire, hence the need for surveillance.

Background

Some Streptococcus pneumoniae isolates identified by routine clinical methods have negative Quellung reaction which may contain other species of viridans group streptococci. And these Streptococcus pneumoniae probably possess distinctive characteristics.

Methods

A total of 105 isolates were involved in the study. Using multi-locus sequence analysis (MLSA) as the standard to determined the species, the identification capacity of the multiplex PCR method were evaluated. The sequence types (STs) were determined following multi-locus sequence typing (MLST) and antimicrobial susceptibilities were tested.

Results

For all 105 isolates, 81 were identified as S.pneumoniae by MLSA, and 24 were S.pseudopneumoniae. Meanwhile, 91.7% (22/24) S.pseudopneumoniae and only 21.0%(17/81) S.pneumoniae isolates were identified correctly by multiplex PCR. In addition, 31 STs were detected from S.pneumoniae i.e. non-encapsulated S.pneumoniae(NESp), 20 of which were new STs. The dominant STs were ST-bj12 (16, 19.8%). The tested antibiotics non-susceptibility rates of S.pseudopneumoniae were comparable to S.pneumoniae.

Conclusions

Some S.pneumoniae isolates with negative Quellung reaction identified in clinical routine work could be S.pseudopneumoniae. Common used methods could not accurately identify the species of them. Most of NESp were determined new STs which revealed heterologous genetics with the encapsulated S. pneumoniae. The resistance S.pseudopneumoniae against common antimicrobials was comparable to NESp.

Background

Streptococcus pneumoniae forms biofilms during asymptomatic carriage, which promotes persistence in the niche, intraspecies, and interspecies communication, and contributes to the development of the invasive pneumococcal disease. In this study, we sought to evaluate biofilm formation and its association with serotype pattern and antibiotic susceptibility of S. pneumoniae strains.

Methods

We investigated 83 S. pneumoniae strains isolated from nasopharyngeal swab samples collected from children under five years of age with acute respiratory infections hospitalized at Khanh Hoa General Hospital between October to December 2015. Biofilm formation was determined by the ability of cells to adhere to the walls and base of 96-well polystyrene dishes. Multiplex PCR assay was used for serotyping, and the microbroth dilution method was performed for 16 antibiotic susceptibility testing.

Results

Biofilm formation occurred in 14 (16.9%) strains of vaccine serotypes. Among these 14.3%, 85.7%, 92.8% and 100% of the isolates had high MICs for penicillin group (≥ 8 µg/mL), tetracycline (≥ 2 µg/mL), clindamycin and erythromycin (≥ 2 µg/mL), and cefaclor (≥ 4 µg/mL) respectively and most of the isolates were PCV13 vaccine serotypes.

Conclusions

We found serotype 19F is widely prevalent in Vietnamese children. Biofilm formation was not found significantly associated with drug susceptibility.

Background

Streptococcus pneumonia colonization in nasopharyng consist of many serotypes, strongly related to high morbidity and mortality of pneumonia in children under-five.This study objective is to compare between S. pneumonia serotypes on nasopharyngeal carriage among children with pneumonia infection and healthy.

Methods

We collected the nasopharyngeal (NP) swab among 130 under-five years of age pneumonia children at M. Djamil hospital and healthy children as control from two daycares in Padang, respectively. Demographic and clinical data were recorded during NP swab collection.The isolate of Streptococcus pneumoniae has been performed by culture on 8% sheep-blood agar plate, were identified serotype by PCR methods.

Results

Overall we found that 19F (21%) and untypeable Streptococcus pneumonia serotype (21%) are the most frequent from PCR identification, followed by 6C, 14 and 34 serotype. Comparing pneumonia cases and healthy children, 19F serotype (22%) more frequent among control healthy children than pneumonia cases (17%). We found untypeable and 6B serotype are the most frequent among pneumonia patiens, but not in control group.

Conclusions

We found the same proportion of 19F serotype Streptococcus pneumoniae among pneumonia patiens and healthy, but very high untypeable serotype in pneumonia patiens.

Background

The aim of this study was to determine the change in serotypes and antibiotic resistance of pneumococcal strains isolated from healthy nasopharyngeal carriers in children from Lima-Perú after introduction of Pneumococcal Conjugate Vaccine (PCV13).

Methods

This was a post-PCV13 observational study (2016 to 2019), in five hospitals in Lima-Perú. Nasopharyngeal swab from 1000 children <2 years was taken. We compare the data with previous pre-PCV13 study (2007 to 2009) in Perú. Pneumococcus was isolated and identified at study laboratory. Antibiotic sensitivity was determined by disc diffusion. Strains were serotyped by Sequential-multiplex-PCR.

Results

Pneumococcal carriers decreases from 27%(573/2123) in pre-PCV13 to 21%(208/1000) in post-PCV13 (p<0.05). The antibiotic resistance increases (p<0.05) for cotrimoxazole(58% to 76%), Oxacillin(52% to 76% non-sensitive), azithromycin(29% to 50%), tetracycline(29% to 39%); and Clindamycin(13% to 29%) in post-PCV13. The most common pre-PCV13 serotype were: 19F(18.1%), 6B(14.3%); 23F(8.9%) and 14(6.5%) and the most common post-PCV13 serotype were: 15B/15C(13.9%), 6A/6B/6C/6D(11.5%) and 19A(5.3%). A positive association (p<0.001) between respiratory symptoms and pneumococcus was observed.

Conclusions

The decrease in pneumococcal nasopharyngeal carrier could be due to use of PCV13 vaccine. The antibiotic resistance is increasing compared to pre-PCV13. 15B/15C represents an emerging non-PCV13 vaccine serotype in our population.