Streptococcus Type Research Articles

A group B streptococcal type VII-secreted LXG toxin mediates interbacterial competition and colonization of the murine female genital tract.

Group B Streptococcus (GBS) asymptomatically colonizes the vagina but can opportunistically ascend to the uterus and be transmitted vertically during pregnancy, resulting in neonatal pneumonia, bacteremia, and meningitis. GBS is a leading etiologic agent of neonatal infection and understanding the mechanisms by which GBS persists within the polymicrobial female genital mucosa has the potential to mitigate subsequent transmission and disease. Type VIIb secretion systems (T7SSb) are encoded by Bacillota and often mediate interbacterial competition using LXG toxins that contain conserved N-termini important for secretion and variable C-terminal toxin domains that confer diverse biochemical activities. Our recent work characterized a role for the GBS T7SSb in vaginal colonization and ascending infection but the mechanisms by which the T7SSb promotes GBS persistence in this polymicrobial niche remain unknown. Herein, we investigate the GBS T7SS in interbacterial competition and GBS niche establishment in the female genital tract. We demonstrate GBS T7SS-dependent inhibition of mucosal pathobiont Enterococcus faecalis both in vitro using predator-prey assays and in vivo in the murine genital tract and found that a GBS LXG protein encoded within the T7SS locus (herein named group B streptococcal LXG Toxin A) contributes to these phenotypes. We identify BltA as a T7SS substrate that is toxic to E. coli and S. aureus upon induction of intracellular expression along with associated chaperones. Finally, we show that BltA and its chaperones contribute to GBS vaginal colonization. Altogether, these data reveal a role for a novel T7b-secreted toxin in GBS mucosal persistence and competition.IMPORTANCECompetition between neighboring, non-kin bacteria is essential for microbial niche establishment in mucosal environments. Gram-positive bacteria encoding T7SSb have been shown to engage in competition through the export of LXG-motif-containing toxins, but these have not been characterized in group B Streptococcus (GBS), an opportunistic colonizer of the polymicrobial female genital tract. Here, we show a role for GBS T7SS in competition with mucosal pathobiont Enterococcus faecalis, both in vitro and in vivo. We further find that a GBS LXG protein contributing to this antagonism is exported by the T7SS and is intracellularly toxic to other bacteria; therefore, we have named this protein group B streptococcal LXG Toxin A (BltA). Finally, we show that BltA and its associated chaperones promote persistence within female genital tract tissues, in vivo. These data reveal previously unrecognized mechanisms by which GBS may compete with other mucosal opportunistic pathogens to persist within the female genital tract.

Identification and characterisation of carbapenem-resistant Streptococcus nidrosiense sp. nov. isolated from blood culture

BackgroundThis study aimed to investigate a highly resistant strain of Streptococcus sp. isolated from a patient with bloodstream infection and determine its taxonomic classification. MethodsThe strain was isolated from blood culture from a 65-year-old male patient admitted to St. Olavs University hospital, Trondheim, Norway, in 2023. Antimicrobial susceptibility testing as well as phenotypic and biochemical characterization were performed. Whole genome sequencing was conducted and genomic comparison to Streptococcus type strains was carried out. ResultsThe strain was initially identified as Streptococcus mitis/oralis but showed significant genetic differences, suggesting that it belonged to an undescribed species within the Streptococcus genus. Phenotypic and biochemical characterization identified the strain as a non-motile, facultative anaerobic bacterium with α-hemolysis. Antimicrobial susceptibility testing showed resistance to all beta-lactams tested. Genomic analyses confirmed the classification of the strain as a novel species, which was designated Streptococcus nidrosiense. ConclusionThis study combines conventional phenotypic tests with whole genome sequencing for accurate taxonomic classification of a bacterial strain isolated from blood culture. The identification of a novel species within the Streptococcus genus contributes to the understanding of microbial diversity and antibiotic resistance of the Streptococcus genus in clinical settings.

Convergent Synthesis of a Group B Streptococcus Type III Epitope Toward a Semisynthetic Carbohydrate-Based Vaccine.

In this work, we synthesized an hexasaccharide derived from the capsular polysaccharide of group B Streptococcus type III capsular polysaccharide. Our convergent 3 + 3 strategy avoided the use of benzyl protecting groups allowing the installation of an azide anchoring group and providing a high yield for the final deprotection steps. Moreover, the minimal hexasaccharidic epitope was conjugated to CRM197 and BSA via copper-catalyzed azide-alkyne cycloaddition for the preparation of a semisynthetic carbohydrate-based vaccine.

A group B streptococcal type VII secreted LXG toxin mediates interbacterial competition and colonization of the female genital tract.

Group B Streptococcus (GBS) asymptomatically colonizes the vagina but can opportunistically ascend to the uterus and be transmitted vertically during pregnancy, resulting in neonatal pneumonia, bacteremia and meningitis. GBS is a leading etiologic agent of neonatal infection and understanding the mechanisms by which GBS persists within the polymicrobial female genital mucosa has potential to mitigate subsequent transmission and disease. Type VIIb secretion systems (T7SSb) are encoded by Firmicutes and often mediate interbacterial competition using LXG toxins that contain conserved N-termini important for secretion and variable C-terminal toxin domains that confer diverse biochemical activities. Our recent work characterized a role for the GBS T7SSb in vaginal colonization and ascending infection but the mechanisms by which the T7SSb promotes GBS persistence in this polymicrobial niche remain unknown. Herein, we investigate the GBS T7SS in interbacterial competition and GBS niche establishment in the female genital tract. We demonstrate GBS T7SS-dependent inhibition of mucosal pathobiont Enterococcus faecalis both in vitro using predator-prey assays and in vivo in the murine genital tract and found that a GBS LXG protein encoded within the T7SS locus (herein named group B streptococcal LXG Toxin A) that contributes to these phenotypes. We identify BltA as a T7SS substrate that is toxic to E. coli and S. aureus upon induction of expression along with associated chaperones. Finally, we show that BltA and its chaperones contribute to GBS vaginal colonization. Altogether, these data reveal a role for a novel T7b-secreted toxin in GBS mucosal persistence and competition.

Characterization of MultidrugResistant serogroup 19 Streptococcus pneumoniae isolated from healthy children below 5 years of age in Indonesia.

We investigated the resistance genes, pilus islets, biofilm formation ability and sequence types of multidrug-resistant Streptococcus pneumoniae (MDRSP) isolated from healthy children below 5 years of age in Indonesia. In all, 104 archived MDRSP isolates from previous carriage studies in Indonesia in 2016-2019 were screened for the presence of antibiotic resistance genes and the rrgC (pilus islet 1) and pitB (pilus islet 2) genes. Multilocus sequence typing and biofilm formation were determined by PCR sequencing and the ability of cells to adhere to the walls, respectively. Results have shown that the mefA, ermB and tetM genes were found in 93, 52 and 100 % of MDRSP isolates, respectively. Insertions of arginine, proline and Ile-100-Leu were the most common mutations in the folA and folP genes. Pilus islets 1 and 2 were discovered in 93 and 82 % of MDRSP isolates, respectively. The MDRSP isolates showed no biofilm formation ability (64 %), and 5 out of 10 strains of MDRSP strains were ST1464. This finding can be used to provide further considerations in implementing and monitoring pneumococcal vaccination in Indonesia.

Comparison of next generation technologies and bioinformatics pipelines for capsular typing of Streptococcus pneumoniae.

Whole genome sequencing (WGS)-based approaches for pneumococcal capsular typing have become an alternative to serological methods. In silico serotyping from WGS has not yet been applied to long-read sequences produced by third-generation technologies. The objective of the study was to determine the capsular types of pneumococci causing invasive disease in Catalonia (Spain) using serological typing and WGS and to compare the performance of different bioinformatics pipelines using short- and long-read data from WGS. All invasive pneumococcal pediatric isolates collected in Hospital Sant Joan de Déu (Barcelona) from 2013 to 2019 were included. Isolates were assigned a capsular type by serological testing based on anticapsular antisera and by different WGS-based pipelines: Illumina sequencing followed by serotyping with PneumoCaT, SeroBA, and Pathogenwatch vs MinION-ONT sequencing coupled with serotyping by Pathogenwatch from pneumococcal assembled genomes. A total of 119 out of 121 pneumococcal isolates were available for sequencing. Twenty-nine different serotypes were identified by serological typing, with 24F (n = 17; 14.3%), 14 (n = 10; 8.4%), and 15B/C (n = 8; 6.7%) being the most common serotypes. WGS-based pipelines showed initial concordance with serological typing (>91% of accuracy). The main discrepant results were found at the serotype level within a serogroup: 6A/B, 6C/D, 9A/V, 11A/D, and 18B/C. Only one discrepancy at the serogroup level was observed: serotype 29 by serological testing and serotype 35B/D by all WGS-based pipelines. Thus, bioinformatics WGS-based pipelines, including those using third-generation sequencing, are useful for pneumococcal capsular assignment. Possible discrepancies between serological typing and WGS-based approaches should be considered in pneumococcal capsular-type surveillance studies.

Exploring Streptococcus pneumoniae capsular typing through MALDI-TOF mass spectrometry and machine-learning algorithms in Argentina: Identifying prevalent NON PCV13 serotypes alongside PCV13 serotypes

IntroductionLaboratory surveillance of Streptococcus pneumoniae serotypes plays a crucial role in effectively implementing vaccines to prevent invasive pneumococcal diseases. The conventional method of serotyping, known as the Quellung reaction, is both time-consuming and expensive. However, the emergence of MALDI-TOF MS technology has revolutionized microbiology laboratories by enabling rapid and cost-effective serotyping based on protein profiles. ObjectivesIn this study, we aimed to investigate the viability of utilizing MALDI-TOF MS technology as an adjunctive and screening method for capsular typing of Streptococcus pneumoniae. Our approach involved developing classification models based on MALDI-TOF MS to discern between Streptococcus pneumoniae strains originating from PCV13 (13-valent pneumococcal conjugate vaccine) and NON PCV13 isolates. MethodsFirstly, we established a comprehensive spectral database comprising isolates of serotypes present in the PCV13 vaccine, along with the top 10 most prevalent NON PCV13 serotypes based on local epidemiological data. This database served as a foundation for developing unsupervised models utilizing MALDI-TOF MS spectra, which enabled us to identify inherent patterns and relationships within the data. Our analysis involved a dataset comprising 215 new isolates collected from nationwide surveillance in Argentina. Our approach involved developing classification models based on MALDI-TOF MS to discern between Streptococcus pneumoniae strains originating from PCV13 (13-valent pneumococcal conjugate vaccine) and NON PCV13 isolates. ResultsAlthough our findings revealed suboptimal performance in serotype classification, they provide valuable insights into the potential of machine learning algorithms in this context. The sensitivity of the models ranged from 0.41 to 0.46, indicating their ability to detect certain serotypes. The observed specificity consistently remained at 0.60, suggesting a moderate level of accuracy in identifying non-vaccine serotypes. These results highlight the need for further refinement and optimization of the algorithms to enhance their discriminative power and predictive accuracy in serotype identification.By addressing the limitations identified in this study, such as exploring alternative feature selection techniques or optimizing algorithm parameters, we can unlock the full potential of machine learning in robust and reliable serotype classification of S. pneumoniae. Our work not only provides a comprehensive evaluation of multiple machine learning models but also emphasizes the importance of considering their strengths and limitations. ConclusionOverall, our study contributes to the growing body of research on utilizing MALDI-TOF MS and machine learning algorithms for serotype identification purposes.

Microbiological aspects of acute odontogenic osteomyelitis in children

Objective: to determine the species composition of pathogens of acute odontogenic inflammatory processes of the jaws in children, to determine the sensitivity and resistance of the isolated microflora to antibiotics of various groups, as well as to determine the dependence of the characteristics of the clinical course of the disease on the type of dominant pathogen. Material and methods. The analysis of the results of microbiological methods for the study of exudate from purulent odontogenic foci of 900 children, due to periostitis and osteomyelitis of the jaws, was carried out. Results. In 65.6% of cases, the causative agent was Pyogenic streptococcus or group A beta-hemolytic streptococcus (BHSA) ith a high level of sensitivity to vancomycin (99%), fluoroquinolones (98%), beta-lactams (91 %) and the highest percentage of resistance to macrolides (41%). Streptococcus viridans (6.1%), Streptococcus pneumoniae (4.3%) and others were also isolated; mixed microflora (14.3%). The syndrome of endogenous intoxication of the body was manifested in 56% of cases by fever, in 38% by leukocytosis, in 57.4% by accelerated ESR. There was no statistically significant difference in the degree of endogenous intoxication in groups with different types of streptococcus. Conclusions. The cause of the inflammatory process of the jaws in 65.6% of cases was BHSA with a high level of sensitivity to vancomycin (99%), fluoroquinolones (98%), beta-lactams (91 %).

Heterogeneity of the group B streptococcal type VII secretion system and influence on colonization of the female genital tract.

Type VIIb secretion systems (T7SSb) in Gram-positive bacteria facilitate physiology, interbacterial competition, and/or virulence via EssC ATPase-driven secretion of small ɑ-helical proteins and toxins. Recently, we characterized T7SSb in group B Streptococcus (GBS), a leading cause of infection in newborns and immunocompromised adults. GBS T7SS comprises four subtypes based on variation in the C-terminus of EssC and the repertoire of downstream effectors; however, the intraspecies diversity of GBS T7SS and impact on GBS-host interactions remains unknown. Bioinformatic analysis indicates that GBS T7SS loci encode subtype-specific putative effectors, which have low interspecies and inter-subtype homology but contain similar domains/motifs and therefore may serve similar functions. We further identify orphaned GBS WXG100 proteins. Functionally, we show that GBS T7SS subtype I and III strains secrete EsxA in vitro and that in subtype I strain CJB111, esxA1 appears to be differentially transcribed from the T7SS operon. Furthermore, we observe subtype-specific effects of GBS T7SS on host colonization, as CJB111 subtype I but not CNCTC 10/84 subtype III T7SS promotes GBS vaginal colonization. Finally, we observe that T7SS subtypes I and II are the predominant subtypes in clinical GBS isolates. This study highlights the potential impact of T7SS heterogeneity on host-GBS interactions.

Concise synthesis of sialic acid containing hexasaccharide corresponding to group B Streptococcus type IX capsular polysaccharide

A convenient block [3 + 2+1] glycosylation strategy has been developed for the synthesis of sialic acid containing hexasaccharide repeating unit having a 2-aminoethyl linker at the reducing end corresponding to the capsular polysaccharide of Group B Streptococcus type IX strain. A disaccharide thioglycoside has been prepared applying “orthogonal latent-active” glycosylation of a thioglycoside acceptor with a thioglycoside donor. A specially designed sialic acid thioglycoside donor has been used to furnish α-glycosidic linkage. Thioglycosides were used as glycosyl donors throughout the synthetic strategy. A combination of N-iodosuccinimide (NIS) and perchloric acid supported over silica (HClO4–SiO2), a solid acid substitute, was used as a thiophilic promoter for the activation of thioglycosides.

Serotype and multilocus sequence typing of Streptococcus suis from diseased pigs in Taiwan

Streptococcus suis (S. suis) infection can cause clinically severe meningitis, arthritis, pneumonia and septicemia in pigs. To date, studies on the serotypes, genotypes and antimicrobial susceptibility of S. suis in affected pigs in Taiwan are rare. In this study, we comprehensively characterized 388 S. suis isolates from 355 diseased pigs in Taiwan. The most prevalent serotypes of S. suis were serotypes 3, 7 and 8. Multilocus sequence typing (MLST) revealed 22 novel sequence types (STs) including ST1831-1852 and one new clonal complex (CC), CC1832. The identified genotypes mainly belonged to ST27, ST94 and ST1831, and CC27 and CC1832 were the main clusters. These clinical isolates were highly susceptible to ceftiofur, cefazolin, trimethoprim/sulfamethoxazole and gentamicin. The bacteria were prone to be isolated from cerebrospinal fluid and synovial fluid in suckling pigs with the majority belonging to serotype 1 and ST1. In contrast, ST28 strains that corresponded to serotypes 2 and 1/2 were more likely to exist in the lungs of growing-finishing pigs, which posted a higher risk for food safety and public health. This study provided the genetic characterization, serotyping and the most current epidemiological features of S. suis in Taiwan, which should afford a better preventative and treatment strategy of S. suis infection in pigs of different production stages.

Capsular typing of Streptococcus pneumoniae isolated from clinical specimens in Gauhati Medical College and hospital, Assam, India

PurposeStreptococcus pneumoniae is an important human respiratory tract pathogen causing pneumococcal diseases in majority of children and adults. The capsule is a significant virulence factor of Pneumococci which determines the bacterial serotype and is the component used for synthesis of pneumococcal vaccines. This cross-sectional study aimed to isolate Streptococcus pneumoniae from clinical samples and determine the occurrence of its circulating serotypes in Assam, North East India. Materials and methodsA total of 80 clinical samples were collected from June 2019 to May 2020 from patients clinically suspected from pneumococcal infection and also included samples routinely sent to bacteriology laboratory. Isolation and identification of S. pneumoniae was performed using conventional culture and molecular methods. Antibiotic susceptibility patterns were monitored. Capsular serotyping was performed using PCR of cpsA gene followed by DNA sequencing. ResultsMajority of the cases suspected of pneumococcal infection belong to the paediatric group aged less than 5 years. Out of 80 samples, 10 (12.50%) were found to be positive by PCR of recP gene. Culture was positive in 80% (8/10) of the total positives. Co-trimoxazole resistance was seen in 33.33% of the isolate from sputum. Serotypes 6A, 6B, 6C and 19F were detected in our region, out of which 6C is a non-vaccine serotype. ConclusionContinued surveillance is needed to monitor trends in non-vaccine serotypes that may emerge as highly associated with antibiotic resistance. Also, the need to continuous monitoring of the antibiotic susceptibility of S. pneumoniae in North eastern parts of India is of outmost importance.

Protective effect of emodin on Streptococcus pneumoniae and matrix-assisted laser desorption time-of-flight mass spectrometry for serotype detection

This study assessed the impact of emodin on Streptococcus pneumoniae serotype using Matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS) technology. After establishment of animal models, rats were classified into sham operation group, model group, low-dose and high-dose emodin group (n = 10, each group). After treatment, the pathology of rat lung tissue was detected along with analysis of the levels of Interleukin-1β, IL-1β(IL-1β), Tumor Necrosis Factor alpha (TNF-α), and IL-6. MALDI-TOF MS was used to examine the serotype of Streptococcus pneumoniae as NF-κB level in the rat lung tissue and capsular polysaccharide protein levels were detected. Compared with healthy tissues, the lung tissues in the model group exhibited collapse of alveoli and infiltration of inflammatory cells, which were greatly alleviated in low-dose and high-dose emodin groups, with more significant effect in high-dose emodin group. Additionally, treatment with emodin dramatically decreased the contents of IL-1β, TNF-α and IL-6 (P <0.05), which were lowest in the high-dose group. 60 representative strains of Streptococcus pneumoniae were divided into 18 mass spectrum types, whilst six serotypes (19F, 19A, 23F, 23A, 3 and 14) were identified. Moreover, 18 strains of serotype 19F accounted for 30% (18/60) and were distributed in 6 different MALDI-TOF MS types, and another 3 serotypes were distributed in the corresponding MALDI-TOF MS types. NF-κB and capsular polysaccharide protein expressions declined after emodin treatment (P <0.05). Collectively, Emodin effectively alleviated infection caused by Streptococcus pneumoniae and inflammatory response and improved conditions of patients while decreasing their levels of NF-κB and capsular polysaccharide protein, affecting typing of Streptococcus pneumoniae.

Prospects for Phagоtherapy of Bacterial Infections Associated with the Provision of Medical Care

Healthcare-associated infections (HAIs) are a global medical and socioeconomic problem. Nosocomial infections occupy one of the leading places among the causes of death in the Russian Federation. About 60–70% of all nosocomial infections are associated with the use of medical implants of various profiles. Pseudomonas aeruginosa, various types of streptococci, staphylococci, Escherichia coli, enterococci (Enterococcus faecalis), Klebsiella pneumoniae, Proteus mirabilis, and representatives of the genus Acinetobacter are highly likely to be found in biofilms of medical supplies. A distinctive feature of microbes that cause HAIs is poly- or even pan-resistance of microbes to recommended antimicrobials. The search for methods and means to overcome is a priority task of modern medicine. Phage therapy seems to be one of the logical and promising ways to combat bacteria that are resistant to conventional therapy. The article outlines the advantages and disadvantages of phage therapy, provides an overview of the successful use of mono- and combined preparations of bacteriophages in the experiment and clinic, as well as modern directions for the use of bacteriophages not only for therapeutic, but also for prophylactic purposes, based on the latest achievements of genetic engineering and biotechnology.

Carriage prevalence, serotype distribution, antimicrobial resistance, pspA typing and pilus islets of Streptococcus pneumoniae isolated from adults living in a Brazilian urban slum.

For Brazilian adults, pneumococcal vaccines have been usually taken only by those who are at higher risk for development of pneumococcal diseases. Since populations from lower socioeconomic status are at high risk of acquiring pneumococcal infections, we investigated the carriage prevalence, colonization risk factors, capsular and surface protein types, and antimicrobial resistance among pneumococcal isolates recovered from adults living in a Brazilian urban slum. Between September-December 2016, we conducted a cross-sectional study among individuals aged≥18years who attended a public primary clinic in Niterói/RJ, Brazil. Pneumococci were isolated by culture on sheep blood agar plates with and without gentamicin. Antimicrobial susceptibility was determined for all isolates. We used PCR to determine capsular types, PspA families (Fam) and pilus islets (PI). Of 385 adults, 32 (8.3%) were pneumococcal carriers. Three carriers had two different pneumococci, totaling 35 isolates. After multivariate analysis, smoking, previous hospitalization, alcohol consumption and co-habitation with children aged<6years increased the odds of pneumococcal carriage, but antibiotic use in the previous 2weeks was found to be a protective factor. Fourteen different serogroups/serotypes were detected and the prevalent ones were 9N/L, 10A, 15B/C and 35F/47F (n=3; 8.6% each). Non-typeable (NT) isolates made up 31.4%. All isolates were susceptible to chloramphenicol, levofloxacin and vancomycin. We found eight (22.9%) penicillin non-susceptible pneumococci (PNSP) with minimum inhibitory concentrations (MICs) of 0.38-1.5μg/mL. The two (5.7%) erythromycin-resistant isolates had MIC>256μg/mL, cMLSB phenotype and the erm(B) gene. Twelve (34.3%) and 17 (48.6%) isolates had PspA Fam1 and Fam2, respectively. Three (8.6%) isolates had genes for pilitwo PI-1 and one PI-2. We detected a low frequency of pneumococcal carriage among the adult population, but a high diversity of serotypes. Frequencies of PNSP and NT isolates resistant to antimicrobial agents are concerning.

Increase in middle ear infections of Streptococcus pyogenes etiology among patients of the Department of Pediatric Otolaryngology of the Medical University of Warsaw in correlation with world reports

Introduction. Beta-hemolytic streptococcus is one of the most common causes of out-of-hospital infections. It can cause local or general infections of varying severity, most commonly in the throat, paranasal sinuses, ear and skin. Some infections are invasive in nature. In the last months of 2022, an alarming increase in infections caused by Streptococcus pyogenes, including invasive infections, has been observed in many countries in Europe and around the world compared to previous years. Aim. The purpose of this study was to compare the number of hospitalized patients with acute otitis media and acute mastoiditis of S. pyogenes etiology in the first six months of 2023 with hospitalizations for the same reason in the previous 5 years, and to assess the correlation with the observed worldwide trend of an increase in the number of observed beta-hemolytic streptococcus type A infections. Material and methods. A retrospective analysis of the data of patients diagnosed with acute otitis media and acute mastoiditis of S. pyogenes etiology hospitalized in the Department of Pediatric Otolaryngology in the first six months of 2023 was carried out, and their number was compared with patients hospitalized for the same reason in the previous 5 years. Results. Between January 2023 and the end of June 2023, 15 patients with acute otitis media were hospitalized in the Department of Pediatric Otolaryngology, in which S. pyogenes was isolated by bacteriological examination. Purulent leakage from the ear was observed in 10 patients. Isolated otitis media was diagnosed in 4 patients. In 10 children, AOM was complicated by acute mastoiditis, which was confirmed by CT scan. The most severe complication was sepsis of GAS etiology. Intravenous antibiotic therapy and surgical treatment were implemented in all patients, achieving a cure. From 2018 to 2022, the number of patients hospitalized for the same reason was significantly lower each year. Conclusions. The number of patients hospitalized in the Department of Otolaryngology in the last two months of 2022 and in the first six months of 2023 due to AOM, as well as AOM complicated by mastoiditis, in which the etiologic agent turned out to be S. pyogenes confirmed the observed worldwide trend towards an increase in the incidence of GAS. GAS-induced AOM is characterized by greater local aggressiveness, manifested by a higher incidence of tympanic membrane perforation, as well as mastoiditis with bone destruction. The primary antibiotic used to treat GAS infections is penicillin, with sensitivity to penicillin also implying sensitivity to all beta-lactam antibiotics. The treatment of GAS with intratemporal complications in the form of acute mastoiditis caused by S. pyogenes, especially progressing with bone destruction, requires combined antimicrobal therapy with surgical treatment.

Effectiveness of nutrient media for the recovery of lyophilisates of fastidious microorganisms: evidence from Streptococcus spp.

To restore the biological and morphological properties of fastidious bacteria during lyophilization, one of which is a type of streptococcus – bacteria of the genus Streptococcus, it is necessary to use expensive specialized nutrient media that are limited in availability for laboratories. In this regard, the purpose of this study was to find the most effective methods of preservation and recovery of fastidious microorganisms using the example of Streptococcus spp. The study was performed by a bacteriological method. The isolates of Streptococcus spp., which had the property of alpha- or beta-haemolysis, were selected for the study. The microorganisms were collected as a result of bacteriological research of pathological and biological materials from 20 animals (10 dogs and 10 cats). Microorganisms were determined and counted using Vitek 2 compact, easySpiral, and Scan 500 systems. As a result, the effectiveness of using various combinations of nutrient media for cryopreservation, freeze-drying, and further revitalization of cultures was proven. It was found that the most effective medium for lyophilization is meat-peptone broth with the addition of 5% bovine blood serum, diluted 1:1 with Faibich’s medium, and for recovery after lyophilization – meat-peptone broth with the addition of 5% blood serum cattle and 5% glucose. With this combination, the concentration of viable cells corresponded to the limits of 1.7×106 -2.4×106 CFU/cm3 . The use of other combinations of nutrient media for the revitalization of Streptococcus bacteria showed lower efficiency, which corresponded to the concentration of viable cells within 1.2×105 -2.1×106 CFU/cm3 . The obtained results increase the efficiency of the method of lyophilization of demanding cultures due to combination of non-selective nutrient media and components available in laboratory practice

Corncob structures in dental plaque reveal microhabitat taxon specificity

BackgroundThe human mouth is a natural laboratory for studying how bacterial communities differ across habitats. Different bacteria colonize different surfaces in the mouth—teeth, tongue dorsum, and keratinized and non-keratinized epithelia—despite the short physical distance between these habitats and their connection through saliva. We sought to determine whether more tightly defined microhabitats might have more tightly defined sets of resident bacteria. A microhabitat may be characterized, for example, as the space adjacent to a particular species of bacterium. Corncob structures of dental plaque, consisting of coccoid bacteria bound to filaments of Corynebacterium cells, present an opportunity to analyze the community structure of one such well-defined microhabitat within a complex natural biofilm. Here, we investigate by fluorescence in situ hybridization and spectral imaging the composition of the cocci decorating the filaments.ResultsThe range of taxa observed in corncobs was limited to a small subset of the taxa present in dental plaque. Among four major groups of dental plaque streptococci, two were the major constituents of corncobs, including one that was the most abundant Streptococcus species in corncobs despite being relatively rare in dental plaque overall. Images showed both Streptococcus types in corncobs in all individual donors, suggesting that the taxa have different ecological roles or that mechanisms exist for stabilizing the persistence of functionally redundant taxa in the population. Direct taxon-taxon interactions were observed not only between the Streptococcus cells and the central corncob filament but also between Streptococcus cells and the limited subset of other plaque bacteria detected in the corncobs, indicating species ensembles involving these taxa as well.ConclusionsThe spatial organization we observed in corncobs suggests that each of the microbial participants can interact with multiple, albeit limited, potential partners, a feature that may encourage the long-term stability of the community. Additionally, our results suggest the general principle that a precisely defined microhabitat will be inhabited by a small and well-defined set of microbial taxa. Thus, our results are important for understanding the structure and organizing principles of natural biofilms and lay the groundwork for future work to modulate and control biofilms for human health.DJxteJ7vGqLvWEg9EZAKHDVideo

Investigation on the virulence of non-encapsulated Streptococcus pneumoniae using liquid agar pneumonia model

IntroductionSince the introduction of pneumococcal conjugate vaccine, there have been warnings of an increase in infections caused by non-vaccine type of Streptococcus pneumoniae strains. Among them, nonencapsulated Streptococcus pneumoniae (NESp) has been reported to cause invasive infections, especially in children and the elderly. Due to low virulence, however, basic experimental reports on invasive infections are limited. MethodsWe applied a liquid-agar method to establish a mouse model of invasive NESp infection. Mice were intratracheally administered a bacterial suspension including agar. With this technique, we investigated the pathogenicity of NESp and the effect of Pneumococcal surface protein K (PspK), a specific surface protein antigen of NESp.NESp wild-type strain (MNZ11) and NESp pspK-deleted mutant strain (MNZ1131) were used in this study. The survival rate, number of bacteria, cytokine/chemokine levels in the bronchoalveolar lavage fluid, and histology of the lung tissue were evaluated. ResultsMice that were intratracheally administered MNZ11 developed lethal pneumonia with bacteremia within 48 h. Conversely, MNZ1131 showed predominantly low lethality without significant pro-inflammatory cytokine production. NESp was found to cause severe pneumonia and bacteremia upon reaching the lower respiratory tract, and PspK was a critical factor of NESp for developing invasive infections. ConclusionsThe current study demonstrated the ability of NESp to develop invasive diseases, especially in connection with PspK by use of a mouse pneumonia model.

Validation of Fourier Transform Infrared Spectroscopy for Serotyping of Streptococcus pneumoniae.

ABSTRACTFourier transform infrared (FT-IR) spectroscopy (IR Biotyper; Bruker) allows highly discriminatory fingerprinting of closely related bacterial strains. In this study, FT-IR spectroscopy-based capsular typing of Streptococcus pneumoniae was validated as a rapid, cost-effective, and medium-throughput alternative to the classical phenotypic techniques. A training set of 233 strains was defined, comprising 34 different serotypes and including all 24 vaccine types (VTs) and 10 non-vaccine types (NVTs). The acquired spectra were used to (i) create a dendrogram where strains clustered together according to their serotypes and (ii) train an artificial neural network (ANN) model to predict unknown pneumococcal serotypes. During validation using 153 additional strains, we reached 98.0% accuracy for determining serotypes represented in the training set. Next, the performance of the IR Biotyper was assessed using 124 strains representing 59 non-training set serotypes. In this setting, 42 of 59 serotypes (71.1%) could be accurately categorized as being non-training set serotypes. Furthermore, it was observed that comparability of spectra was affected by the source of the Columbia medium used to grow the pneumococci and that this complicated the robustness and standardization potential of FT-IR spectroscopy. A rigorous laboratory workflow in combination with specific ANN models that account for environmental noise parameters can be applied to overcome this issue in the near future. The IR Biotyper has the potential to be used as a fast, cost-effective, and accurate phenotypic serotyping tool for S. pneumoniae.