Streptococcus pneumoniae colonization is required to alter the nasal microbiota in cigarette smoke-exposed mice.

Infect Immun. 2017 Jul 31. pii: IAI.00434-17. doi: 10.1128/IAI.00434-17. [Epub ahead of print]

Streptococcus pneumoniae colonization is required to alter the nasal microbiota in cigarette smoke-exposed mice.

Shen P1, Whelan FJ2,3, Schenck LP2,3, McGrath JJC1, Vanderstocken G4, Bowdish DME3,4, Surette MG2,3,5,6, Stämpfli MR7,8.

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Abstract

Smokers have nasal microbiota dysbiosis, with an increased frequency of colonizing bacterial pathogens. It is possible that cigarette smoke increases pathogen acquisition by perturbing the microbiota and decreasing colonization resistance. However, it is difficult to disentangle microbiota dysbiosis due to cigarette smoke exposure from microbiota changes caused by increased pathogen acquisition in human smokers. Utilizing an experimental mouse model, we investigated the impact of cigarette smoke on the nasal microbiota in the absence and presence of nasal pneumococcal colonization. We observed that cigarette smoke exposure alone did not alter nasal microbiota composition. Microbiota composition was also unchanged at 12 hours following low dose nasal pneumococcal inoculation, suggesting the ability of the microbiota to resist initial nasal pneumococcal acquisition was not impaired in smoke-exposed mice. However, nasal microbiota dysbiosis occurred as a consequence of established high dose nasal pneumococcal colonization at day 3 in smoke-exposed mice. Similar to clinical reports in human smokers, we observed an enrichment of potentially pathogenic bacterial genera such as Fusobacterium, Gemella, and Neisseria Our findings suggest that cigarette smoke exposure predisposes to pneumococcal colonization independent of changes to the nasal microbiota, and microbiota dysbiosis observed in smokers may occur as a consequence of established pathogen colonization.

Copyright © 2017 American Society for Microbiology.

PMID: 28760931 DOI: 10.1128/IAI.00434-17

The Protein Interactome of Streptococcus pneumoniae and Bacterial Meta-interactomes Improve Function Predictions.

mSystems. 2017 Jun 6;2(3). pii: e00019-17. doi: 10.1128/mSystems.00019-17. eCollection 2017 May-Jun.

The Protein Interactome of Streptococcus pneumoniae and Bacterial Meta-interactomes Improve Function Predictions.

Wuchty S1,2,3,4, Rajagopala SV5, Blazie SM5, Parrish JR6, Khuri S1,2, Finley RL Jr6, Uetz P7.

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Abstract

The functions of roughly a third of all proteins in Streptococcus pneumoniae, a significant human-pathogenic bacterium, are unknown. Using a yeast two-hybrid approach, we have determined more than 2,000 novel protein interactions in this organism. We augmented this network with meta-interactome data that we defined as the pool of all interactions between evolutionarily conserved proteins in other bacteria. We found that such interactions significantly improved our ability to predict a protein's function, allowing us to provide functional predictions for 299 S. pneumoniae proteins with previously unknown functions. IMPORTANCE Identification of protein interactions in bacterial species can help define the individual roles that proteins play in cellular pathways and pathogenesis. Very few protein interactions have been identified for the important human pathogen S. pneumoniae. We used an experimental approach to identify over 2,000 new protein interactions for S. pneumoniae, the most extensive interactome data for this bacterium to date. To predict protein function, we used our interactome data augmented with interactions from other closely related bacteria. The combination of the experimental data and meta-interactome data significantly improved the prediction results, allowing us to assign possible functions to a large number of poorly characterized proteins.

KEYWORDS:

functional prediction; protein-protein interactions

PMID: 28744484 PMCID: PMC5513735 DOI: 10.1128/mSystems.00019-17

Mathematical modeling of postcoinfection with influenza A virus and Streptococcus pneumoniae, with implications for pneumonia and COPD-risk assessment.

Int J Chron Obstruct Pulmon Dis. 2017 Jul 5;12:1973-1988. doi: 10.2147/COPD.S138295. eCollection 2017.

Mathematical modeling of postcoinfection with influenza A virus and Streptococcus pneumoniae, with implications for pneumonia and COPD-risk assessment.

Cheng YH1, You SH2, Lin YJ3, Chen SC4,5, Chen WY6, Chou WC2, Hsieh NH7, Liao CM3.

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Abstract

BACKGROUND:

The interaction between influenza and pneumococcus is important for understanding how coinfection may exacerbate pneumonia. Secondary pneumococcal pneumonia associated with influenza infection is more likely to increase respiratory morbidity and mortality. This study aimed to assess exacerbated inflammatory effects posed by secondary pneumococcal pneumonia, given prior influenza infection.

MATERIALS AND METHODS:

A well-derived mathematical within-host dynamic model of coinfection with influenza A virus and Streptococcus pneumoniae (SP) integrated with dose-response relationships composed of previously published mouse experimental data and clinical studies was implemented to study potentially exacerbated inflammatory responses in pneumonia based on a probabilistic approach.

RESULTS:

We found that TNFα is likely to be the most sensitive biomarker reflecting inflammatory response during coinfection among three explored cytokines. We showed that the worst inflammatory effects would occur at day 7 SP coinfection, with risk probability of 50% (likely) to develop severe inflammatory responses. Our model also showed that the day of secondary SP infection had much more impact on the severity of inflammatory responses in pneumonia compared to the effects caused by initial virus titers and bacteria loads.

CONCLUSION:

People and health care workers should be wary of secondary SP infection on day 7 post-influenza infection for prompt and proper control-measure implementation. Our quantitative risk-assessment framework can provide new insights into improvements in respiratory health especially, predominantly due to chronic obstructive pulmonary disease (COPD).

KEYWORDS:

chronic obstructive pulmonary disease; coinfection; influenza; modeling; pneumonia; risk assessment

PMID: 28740377 PMCID: PMC5505164 DOI: 10.2147/COPD.S138295

Effect of decreased BCAA synthesis through disruption of ilvC gene on the virulence of Streptococcus pneumoniae.

Arch Pharm Res. 2017 Jul 22. doi: 10.1007/s12272-017-0931-0. [Epub ahead of print]

Effect of decreased BCAA synthesis through disruption of ilvC gene on the virulence of Streptococcus pneumoniae.

Kim GL1, Lee S1, Luong TT1, Nguyen CT1, Park SS1, Pyo S1, Rhee DK2.

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Abstract

Streptococcus pneumoniae (pneumococcus) is responsible for significant morbidity and mortality worldwide. It causes a variety of life-threatening infections such as pneumonia, bacteremia, and meningitis. In bacterial physiology, the metabolic pathway of branched-chain amino acids (BCAAs) plays an important role in virulence. Nonetheless, the function of IlvC, one of the enzymes involved in the biosynthesis of BCAAs, in S. pneumoniae remains unclear. Here, we demonstrated that downregulation of BCAA biosynthesis by ilvC ablation can diminish BCAA concentration and expression of pneumolysin (Ply) and LytA, and subsequently attenuate virulence. Infection with an ilvC mutant showed significantly reduced mortality and colonization in comparison with strain D39 (serotype 2, wild type), suggesting that ilvC can potentiate S. pneumoniae virulence due to adequate BCAA synthesis. Taken together, these results suggest that the function of ilvC in BCAA synthesis is essential for virulence factor and could play an important role in the pathogenesis of respiratory infections.

KEYWORDS:

BCAA; Colonization; Streptococcus pneumoniae; Virulence; ilvC

PMID: 28735462 DOI: 10.1007/s12272-017-0931-0

 

 

Pneumonia and Streptococcus pneumoniae vaccine.

Arch Pharm Res. 2017 Jul 22. doi: 10.1007/s12272-017-0933-y. [Epub ahead of print]

Pneumonia and Streptococcus pneumoniae vaccine.

Kim GL1, Seon SH1, Rhee DK2.

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Abstract

Pneumonia is an inflammatory disease of the lung, responsible for high morbidity and mortality worldwide. It is caused by bacteria, viruses, fungi, or other microorganisms. Streptococcus pneumoniae, a gram-positive bacterium with over 90 serotypes, is the most common causative agent. Moreover, comorbid factors including heart failure, renal disease, and pulmonary disease could increase the risk of pneumococcal pneumonia. Since the advent of the pneumococcal vaccine in the 1980s, the incidence of pneumonia has decreased significantly. However, current vaccines confer only limited protection against serotypes included in the vaccine. Thus, to overcome this limitation, new types of pneumococcal vaccines have been sought and under clinical trials. In this review, we discuss pneumonia and summarize the various types of pneumococcal vaccines in progress.

KEYWORDS:

Pneumococcal vaccine; Pneumonia; Streptococcus pneumoniae

PMID: 28735461 DOI: 10.1007/s12272-017-0933-y

Clinical streptococcal isolates, distinct from Streptococcus pneumoniae, but containing the β-glucosyltransferase tts gene and expressing serotype 37 capsular polysaccharide.

PeerJ. 2017 Jul 18;5:e3571. doi: 10.7717/peerj.3571. eCollection 2017.

Clinical streptococcal isolates, distinct from Streptococcus pneumoniae, but containing the β-glucosyltransferase tts gene and expressing serotype 37 capsular polysaccharide.

Sheppard CL1, Kapatai G1, Broughton K1, Schaefer U2, Hannah M3, Litt DJ1, Fry NK1.

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Abstract

The major virulence factor of the pneumococcus, and target for conjugate vaccines, is the polysaccharide capsule, which is usually encoded by the highly variable cps locus. Serotype 37 is an unusual pneumococcal type in which the single β-glucosyltransferase gene responsible for serotype capsule production (tts) is located outside of the capsular operon region. Using a previously described automated whole genome sequence (WGS)-based serotyping bioinformatics tool, PneumoCaT, we identified and investigated seven clinical isolates (three from blood cultures) of non-pneumococcal streptococci containing a highly homologous tts and included them in a study panel of 20 isolates which included a 11 further clinical isolates of S. pneumoniae serotype 37, a reference strain of serotype 37 and the S. pseudopneumoniae type strain BAA 960T. The seven non-pneumococcal isolates generated novel alleles at all pneumococcal MLST loci and gave low percentage similarity (<45%) to S. pneumoniae or S. pseudopneumoniae species by comparison of short sequence patterns in genomic data (k-mer analysis). The S. pseudopneumoniae BAA-960T isolate generated two novel alleles in the MLST and gave a high similarity (>99%) to the reference sequence for BAA-960T. Twelve isolates gave high similarity (>77%) to the Streptococcus pneumoniae 5652-06 serotype 19A reference genome sequence and had previously reported MLST alleles. Each of the seven clinical non-pneumococcal strains and all of the 12 S. pneumoniae possessed a β-glycosyltransferase gene (tts) with >95% similarity to the pneumococcal tts reference DNA sequence with 20-22 non-synonymous SNPs. All but two strains in which the tts gene was detected gave positive reactions for serotype 37 in slide agglutination tests with serotype 37 typing sera. Phylogenetic analysis using both SNP and MLST data showed distinct clades corresponding to strains identified as pneumococcus or non-pneumococcus by kmer WGS analysis. Extended k-mer database analysis and ribosomal MLST placed the non-pneumococcal isolates within the S. mitis group. Biochemical and bile solubility assays showed differences between the unusual isolates and S. pneumoniae. All isolates had detectable pneumolysin (ply) genes, but only those that identified as pneumococcus contained the genes for autolysin (lytA) or the ABC transporter lipoprotein A (piaA) with >80% coverage and >95% similarity. Here we report the existence of a novel group of strains distinct from S. pneumoniae, but which can express a pneumococcal serotype 37 capsular polysaccharide which can be associated with clinical disease.

KEYWORDS:

Microbial genomics; Microbial identification; Phylogenetics; Streptococci

PMID: 28729954 PMCID: PMC5518733 DOI: 10.7717/peerj.3571

Identification of Antipneumococcal Molecules Effective Against Different Streptococcus pneumoniae Serotypes Using a Resazurin-Based High-Throughput Screen.

Assay Drug Dev Technol. 2017 Jul;15(5):198-209. doi: 10.1089/adt.2017.789.

Identification of Antipneumococcal Molecules Effective Against Different Streptococcus pneumoniae Serotypes Using a Resazurin-Based High-Throughput Screen.

Kim HJ1, Kim N2, Shum D2, Huddar S3,4, Park CM3, Jang S1.

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Abstract

Streptococcus pneumoniae is a major human pathogen, causing around 1.6 million deaths worldwide each year. By optimizing a resazurin-based assay to detect S. pneumoniae growth in 384-well microplates, we developed a new high-throughput screening (HTS) system for the discovery of antipneumococcal molecules, which was unsuccessful using conventional absorbance measurements. Before applying our protocol to a large-scale screen, we validated the system through a pilot screen targeting about 7,800 bioactive molecules using three different S. pneumoniae serotypes. Primary screenings of a further 27,000 synthetic small molecules facilitated the identification of 3-acyl-2-phenylamino-1,4-dihydropquinolin-4-one (APDQ) derivatives that inhibited growth of S. pneumoniae with MIC90 values <1 μM (0.03-0.81 μM). Five selected APDQ derivatives were also active against Staphylococcus aureus but neither Klebsiella pneumoniae nor Pseudomonas aeruginosa, suggesting that APDQ may act specifically against Gram-positive bacteria. Our results both validated and demonstrated the utility of the resazurin-based HTS system for the identification of new antipneumococcal molecules. Moreover, the identified new antipneumococcal molecules in this study may have potential to be further developed as new antibiotics.

KEYWORDS:

Streptococcus pneumoniae; antipneumococcals; high-throughput screening; resazurin

PMID: 28723269 DOI: 10.1089/adt.2017.789

Identification of EloR (Spr1851) as a regulator of cell elongation in Streptococcus pneumoniae.

Mol Microbiol. 2017 Jul 15. doi: 10.1111/mmi.13748. [Epub ahead of print]

Identification of EloR (Spr1851) as a regulator of cell elongation in Streptococcus pneumoniae.

Stamsås GA1, Straume D1, Ruud Winther A1, Kjos M1, Frantzen CA1, Håvarstein LS1.

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Abstract

In a screen for mutations suppressing the lethal loss of PBP2b in Streptococcus pneumoniae we identified Spr1851 (named EloR), a cytoplasmic protein of unknown function whose inactivation removed the requirement for PBP2b as well as RodA. It follows from this that EloR and the two elongasome proteins must be part of the same functional network. This network also includes StkP, as this serine/threonine kinase phosphorylates EloR on threonine 89 (T89). We found that ΔeloR cells, and cells expressing the phosphoablative form of EloR (EloRT89A ), are significantly shorter than wild-type cells. Furthermore, the phosphomimetic form of EloR (EloRT89E ) is not tolerated unless the cell in addition acquires a truncated MreC or non-functional RodZ protein. By itself, truncation of MreC as well as inactivation of RodZ gives rise to less elongated cells, demonstrating that the stress exerted by the phosphomimetic form of EloR is relieved by suppressor mutations that reduce or abolish the activity of the elongasome. Of note, it was also found that loss of elongasome activity caused by truncation of MreC elicits increased StkP-mediated phosphorylation of EloR. Together, the results support a model in which phosphorylation of EloR stimulates cell elongation, while dephosphorylation has an inhibitory effect.

© 2017 John Wiley & Sons Ltd.

PMID: 28710862 DOI: 10.1111/mmi.13748

Different Behavior and Response of Staphylococcus Epidermidis and Streptococcus Pneumoniaeto a Ventriculoperitoneal Shunt: An in vitro Study.

Pediatr Neurosurg. 2017;52(4):257-260. doi: 10.1159/000477817. Epub 2017 Jul 14.

Different Behavior and Response of Staphylococcus Epidermidis and Streptococcus Pneumoniaeto a Ventriculoperitoneal Shunt: An in vitro Study.

Heidari V1, Habibi ZHojjati Marvasti AEbrahim Soltani ZNaderian NTanzifi PNejat F.

Author information

Abstract

BACKGROUND:

Pneumococcal shunt infection is a rare event. There is no consensus on the therapeutic management of this kind of shunt infection according to literature reviews, and it seems to be different from infection with Staphylococcus epidermidis. We studied 2 shunted patients with pneumococcal meningitis, both of whom were treated with only antibiotics. The management of these cases seems to be different from that of shunt catheter infection due to these bacteria. We conducted a laboratory study to show the different behavior of pneumococcus compared to S. epidermidis regarding shunt catheter colonization.

MATERIALS AND METHODS:

S. epidermidis and Streptococcus pneumoniae bacteria isolated from the cerebrospinal fluid of meningitis patients were incubated in sterile media. Forty-five segments of shunt catheter from silicone material were placed in 45 separate media of S. epidermidis and pneumococcus. Then each catheter was washed and cultured in blood chocolate agar growth medium in separate petri dishes via the roll plate method. The dishes were extracted from the incubator and the colony count was calculated after 72 h.

RESULTS:

The colony count was obviously different between the 2 bacteria groups, with a higher count related to S. epidermidis dishes. The colony count of the pneumococcal petri dishes was 25-35,000 (mean 14,337) and for dishes with S. epidermidis it was 14,000-100,000 (mean 50,125) (p = 0.001).

CONCLUSION:

The adherence of pneumococcus to shunt catheters seems to be much less than that of S. epidermidis, which produced a very low colony count when incubated with the catheter in the medium culture. S. pneumoniae meningitis in shunted patients can be managed successfully with only antibiotics. This approach can prevent problems related to the several additional surgeries required for shunt removal, a new shunt insertion, and the management of high intracranial pressure.

© 2017 S. Karger AG, Basel.

KEYWORDS:

Colonization; Infection; Staphylococcus epidermidis; Streptococcus pneumoniae; Treatment; Ventriculoperitoneal shunt

PMID: 28704823 DOI: 10.1159/000477817

Complete Genome Sequence of Streptococcus pneumoniae Virulent Phage MS1.

Genome Announc. 2017 Jul 13;5(28). pii: e00333-17. doi: 10.1128/genomeA.00333-17.

Complete Genome Sequence of Streptococcus pneumoniae Virulent Phage MS1.

Kot W1, Sabri M2, Gingras H3, Ouellette M3, Tremblay DM2,4,5, Moineau S6,4,5.

Author information

Abstract

The lytic Streptococcus pneumoniae phage MS1 was isolated from a throat swab of a patient with symptoms of upper respiratory tract infection. The genome of this siphophage has 56,075 bp, 42.3% G+C content, and 77 open reading frames, including queuosine biosynthesis genes. Phage MS1 is related to pneumococcal phage Dp-1.

Copyright © 2017 Kot et al.

PMID: 28705957 PMCID: PMC5511896 DOI: 10.1128/genomeA.00333-17

Development of PCRSeqTyping-a novel molecular assay for typing of Streptococcus pneumoniae.

Pneumonia (Nathan). 2017 May 25;9:8. doi: 10.1186/s41479-017-0032-3. eCollection 2017.

Development of PCRSeqTyping-a novel molecular assay for typing of Streptococcus pneumoniae.

Nagaraj G1, Ganaie F1, Govindan V1, Ravikumar KL1.

Author information

Abstract

BACKGROUND:

Precise serotyping of pneumococci is essential for vaccine development, to better understand the pathogenicity and trends of drug resistance. Currently used conventional and molecular methods of serotyping are expensive and time-consuming, with limited coverage of serotypes. An accurate and rapid serotyping method with complete coverage of serotypes is an urgent necessity. This study describes the development and application of a novel technology that addresses this need.

METHODS:

Polymerase chain reaction (PCR) was performed, targeting 1061 bp cpsB region, and the amplicon was subjected to sequencing. The sequence data was analyzed using the National Centre for Biotechnology Information database. For homologous strains, a second round of PCR, sequencing, and data analysis was performed targeting 10 group-specific genes located in the capsular polysaccharide region. Ninety-one pneumococcal reference strains were analyzed with PCRSeqTyping and compared with Quellung reaction using Pneumotest Kit (SSI, Denmark).

RESULTS:

A 100% correlation of PCRSeqTyping results was observed with Pneumotest results. Fifty-nine reference strains were uniquely identified in the first step of PCRSeqTyping. The remaining 32 homologous strains out of 91 were also uniquely identified in the second step.

CONCLUSION:

This study describes a PCRSeqTyping assay that is accurate and rapid, with high reproducibility. This assay is amenable for clinical testing and does not require culturing of the samples. It is a significant improvement over other methods because it covers all pneumococcal serotypes, and it has the potential for use in diagnostic laboratories and surveillance studies.

KEYWORDS:

Molecular serotyping; PCRSeqTyping; Streptococcus pneumoniae; cpsB sequencing

PMID: 28702310 PMCID: PMC5471960 DOI: 10.1186/s41479-017-0032-3

CRH Affects the Phenotypic Expression of Sepsis-Associated Virulence Factors by Streptococcus pneumoniae Serotype 1 In vitro.

Front Cell Infect Microbiol. 2017 Jun 22;7:263. doi: 10.3389/fcimb.2017.00263. eCollection 2017.

CRH Affects the Phenotypic Expression of Sepsis-Associated Virulence Factors by Streptococcus pneumoniae Serotype 1 In vitro.

Ngo Ndjom CG1, Kantor LV2, Jones HP1.

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Abstract

Sepsis is a life-threatening health condition caused by infectious pathogens of the respiratory tract, and accounts for 28-50% of annual deaths in the US alone. Current treatment regimen advocates the use of corticosteroids as adjunct treatment with antibiotics, for their broad inhibitory effect on the activity and production of pro-inflammatory mediators. However, despite their use, corticosteroids have not proven to be able to reverse the death incidence among septic patients. We have previously demonstrated the potential for neuroendocrine factors to directly influence Streptococcus pneumoniae virulence, which may in turn mediate disease outcome leading to sepsis and septic shock. The current study investigated the role of Corticotropin-releasing hormone (CRH) in mediating key markers of pneumococcal virulence as important phenotypic determinants of sepsis and septic shock risks. In vitro cultures of serotype 1 pneumococcal strain with CRH promoted growth rate, increased capsule thickness and penicillin resistance, as well as induced pneumolysin gene expression. These results thus provide significant insights of CRH-pathogen interactions useful in understanding the underlying mechanisms of neuroendocrine factor's role in the onset of community acquired pneumonias (CAP), sepsis and septic shock.

KEYWORDS:

Streptococcus pneumoniae; corticotropin releasing hormone; phenotype; sepsis virulence; serotypes

PMID: 28690980 PMCID: PMC5479890 DOI: 10.3389/fcimb.2017.00263