Streptococcus pneumoniae is the causative agent of a multitude of diseases and further study into its pathogenies is vital. The pneumococcus is genetically malleable and several tools are available to manipulate this pathogen. In this study, we attempted to utilize one such tool, the Sweet Janus cassette, to replace the capsule locus with other capsule loci in our strain background and found that the efficiency of allelic replacement was low and the number of revertant false-positive colonies was high. We determined that the capacity to recombine capsule varied by the initial isolated colony, suggesting that frequency of reversion is dependent on the bacterial cell line. Alternative selection markers may further expand the application of Sweet Janus. We created novel cassettes that utilized chlorinated phenylalanine as an alternative counter-selection agent in conjunction with the Janus or Sweet Janus cassette, providing a new dual or triple selection marker. Moreover, we created cassettes that do not require engineered resistance in the background strain, including both single and dual selection markers. We were able to utilize all constructs in allelic replacement of the capsule loci. These novel constructs provide a new means for generating gene deletions in S. pneumoniae that expand experimental applications.

Aim: Streptococcus pneumoniae and influenza H1N1 virus are common organisms associated with human infections. These infections could play a significant role in immune regulation. The study was performed to analyse the genome sequences of these organisms with human genome and study its functional significance. Methods: The study was performed to analyse the overlapping of genome sequences in Streptococcus pneumoniae and Influenza (H1N1) virus against human genome sequences by BLASTn sequence analysis. The alignments are studied against the corresponding genes for their functional significance with DAVID and NDEx software.Results: Several hits or overlapping nucleotide segments were identified. Between streptococcus and homo sapiens 287 overlaps were identified, and among influenza and homo sapiens 124 hits were identified. A wide range of functional significance of these genes were identified, and the results are presented in this study. The results show insights into functional pathways and biological activities associated with the respective vaccinations or infections by these microorganisms. Conclusion: The common organisms like Streptococcus pneumoniae and Influenza H1N1 virus actively interact with the immune system and result in a wide range of immune regulations.

Introduction. Streptococcus pneumoniae infections are a major cause of mortality and morbidity worldwide. In Jordan, pneumococcal conjugate vaccines (PCVs) are not included in the national vaccination program. Due to the current availability of several PCVs including PCV-10, PCV-13 and PCV-15, along with PCV-20, currently undergoing pediatric approvals globally, the decision to introduce PCVs and their selection should be based on valid local data on the common serotypes of Streptococcus pneumoniae. Methods: This cross-sectional study aimed to identify the frequency of serotypes of Streptococcus pneumoniae in children aged below 5 years hospitalized with invasive pneumococcal diseases (IPD) including pneumonia, septicemia and meningitis during the study’s duration in representative areas of Jordan. Serotyping for culture-positive cases was based on the capsular reaction test, known as the Quellung reaction. qPCR was conducted on blood samples of patients with lobar pneumonia identified via X-ray or on cerebrospinal fluid for those with a positive latex agglutination test for Streptococcus pneumoniae. Results. This study was based on the analysis of the serotypes of 1015 Streptococcus pneumoniae cases among children younger than the age of 5; 1006 cases with pneumonia, 6 cases with meningitis, and 3 cases with septicemia. Only 23 culture-positive cases were identified, in comparison to 992 lobar pneumonia cases which were PCR-positive but culture-negative, with a PCR positivity rate of 92%. Serotypes 6B, 6A, 14 and 19F were the most common serotypes identified in the study, with prevalence rates of 16.45%, 13.60%, 12.12% and 8.18%, respectively. PCV-10, PCV-13, PCV-15 and PCV-20 coverage rates were 45.32%, 61.87%, 64.14% and 68.47%, respectively. Discussion: To the best of our knowledge, this is largest prospective study from the Middle East and one of the largest studies worldwide showing the serotypes of Streptococcus pneumoniae. It reveals the urgency for the introduction of PCV vaccination in Jordan, utilizing recently developed vaccines with broader serotype coverage.

Objective. Whether a minimum quantity of saliva is needed to inhibit the caries process is unclear. Here, we evaluated the effect of saliva dilutions on an in vitro caries model with Streptococcus mutans (S. mutans) biofilms. Methods. S. mutans biofilms were grown on enamel and root dentin slabs, in culture media containing different proportions of saliva (v/v): 0%, 5%, 10%, 25%, 50%, 75% and 100% saliva, and exposed to a 10% sucrose solution (5 min, 3x/day), with appropriate controls. After 5 (enamel) and 4 (dentin) days, demineralization, biomass, viable bacteria and polysaccharide formation were analyzed. The acidogenicity of the spent media was monitored overtime. Assays were carried out in triplicate in 2 independent experiments (n=6). Results. An inverse relationship was observed between acidogenicity, demineralization, and saliva proportion, both in enamel and dentin. A marked reduction in enamel and dentin demineralization was observed when small amounts of saliva were incorporated in the medium. For both tissues, a significant reduction in biomass, viable S. mutans cells and polysaccharides were observed when saliva was present, in a concentration-dependent manner. Conclusions. High quantities of saliva can almost completely inhibit sucrose-induced cariogenicity, but small amounts can also exert a dose-dependent caries-protective effect.

Urinary infections are very prevalent in pregnant women and are a cause for great concern con-sidering the negative impacts they can have on both, the mother and the baby. The objectives were characterize urinary infections associated with pregnant women, study the most prevalent strains in urinary infections in pregnant women and analyze the antibiogram of the most prevalent strains in infections in pregnant women. A retrospective observational study was carried out on all posi-tive urine cultures from pregnant women between January 2018 and December 2022 at a Hospital Center in the Center of Portugal, totaling 201 samples. Data were collected with computer support, including age, origin, previous antibiotic therapy, catheterization, isolated bacteria and tested an-tibiotic therapy. The majority of pregnant women were in the third trimester of pregnancy and came from the External Consultation. The most identified bacteria was Escherichia coli, followed by Streptococcus agalactiae. Regarding the interaction with antibiotics, Escherichia coli showed total sensitivity to one antibiotic, while Streptococcus agalactiae showed sensitivity to four anti-biotics in 2022. This work contributes to the knowledge of urinary infections in pregnant women in the center of the country, being a contribution to the continued improvement of the care provided

Background: The use of nitinol (NiTi) archwires in orthodontic treatment has expanded significantly due to unique mechanical properties. The greatest barrier to safe orthodontic treatment is chemically or microbiologically induced corrosion, resulting in Ni2+ release. The aim of this investigation was to enhance corrosion resistance and introduction antibacterial properties to NiTi archwire by coating them with TiN-Cu. Methods: NiTi archwires were coated with TiN-Cu using cathodic arc evaporation and direct current magnetron sputtering. The morphology of the sample was analyzed by FESEM and the chemical composition was assessed using EDS, XRD and FTIR. Inductively coupled plasma-optical emission spectrometry was used to estimate the ion release. Biocompatibility of samples was investigated using MTT test. Antibacterial activity was analyzed against Streptococcus mutans and Streptococcus mitis. Results: Physico-chemical characterization revealed well-designed coatings with the presence of TiN phase with incorporated Cu2+. TiN-Cu coated archwires showed statistically lower Ni2+ release (p<0.05). Relative cell viability was the highest regarding 28-day eluates of TiN-Cu coated archwires (p<0.05). The most remarkable decrease in Streptococcus mitis concentrations was observed in case of TiN-Cu coated archwires (p<0.05). Conclusion: Taking into account biocompatibility and antibacterial tests, TiN-Cu coated archwires may be considered as a good candidate further clinical investigations.

Streptococcus intermedius is frequently associated with brain and liver abscesses, while pleuropulmonary infections are considered rarer. Even less frequent is the association of lung and brain abscess due to this agent with left heart endocarditis. We describe the case of a 40-year-old man with a brain abscess due to S. intermedius and concomitant lung abscess and aortic native valve endocarditis. He was treated with surgical drainage of the brain abscess and a 4-week course of intravenous ceftriaxone, followed by oral amoxicillin/clavulanate, obtaining healing of the lesions without relapse of the infection.

Background: Pneumococcal carriage surveillance study took place in urban and rural areas for Jordanian children in the period 2015-2019. Objectives: Determine urban and rural differences in pneumococcal carriage rate, resistance, and serotypes from healthy Jordanian children of Amman (urban) and eastern Madaba (rural). Methods: Nasopharyngeal swabs (NP) were taken from 682 children aged 1 to 163 months. Pneumococcal identification, serotyping and resistance were done according to standard method. Results: Number of cases tested for Amman 267 and for eastern Madaba 415. Carriage rate for eastern Madaba was 39.5% and for Amman 31.1%. Predominant serotypes for eastern Madaba and Amman were 19F (21.3%; 15.7%), 23F (12.2%; 9.6%), 14 (6.7%; 2.4%), 19A (4.9%; 2.4%), 6A (5.5%; 3.6%). Resistance rates for eastern Madaba and Amman were: penicillin (95.8%; 81.9%), clarithromycin (68.9%; 59.0%), clindamycin (40.8%; 31.3%), and trimethoprim-sulfamethoxazole (73.2%; 61.4%). Coverage of PCV7, PCV13, and the future PCV20 for Amman were 42.2%, 48.2%, and 60.2%; and for eastern Madaba were 50.0%, 62.2%, and 73.2%, respectively. In Amman 25.8% have received 1-3 PCV7 injections compared to 1.9% in eastern Madaba. Conclusions: There was significant differences in carriage, resistance and coverage in both regions. The potential inclusion of PCV vaccination program for rural areas is essential.

Streptococcus pneumoniae causes invasive infections such as otitis media, pneumonia and meningitis. It produces pneumolysin (Ply) toxin, which forms a pore to host cell membrane and has multiple functions in S. pneumoniae pathogenesis. The Ply C-terminal domain 4 mediates binding to membrane cholesterol and induces the formation of pores composed of up to 40 Ply monomers. Ply has a key role in the establishment of nasal colonization, pneumococcal transmission from host to host and pathogenicity. Altogether, 27 hydrolyzable tannins were tested for Ply inhibition in hemolysis assay and tannin-protein precipitation assay. Pentagalloylglucose (PGG) and gemin A showed nanomolar inhibitory activity. Ply oligomerization on the erythrocyte surface was inhibited with PGG. PGG also inhibited Ply cytotoxicity to A549 human lung epithelial cells. Molecular modelling of Ply interaction with PGG suggested that it binds to the pocket formed by domains 2, 3 and 4. In this study, we reveal the structural features of hydrolyzable tannins that are required for interaction with Ply. Monomeric hydrolysable tannins containing a sufficient number of polyvalent and flexible galloyl groups have highest inhibitory power to Ply cytotoxicity, and are followed by oligomers. Of the oligomers, macrocyclic and C-glycosidic structures were weaker in their inhibition than the glucopyranose-based oligomers. Accordingly, PGG-type monomers and certain oligomers might have therapeutic value in the targeting of S. pneumoniae infections.

The 10-valent pneumococcal vaccine was introduced in Pakistan’s Expanded Program on Immunization (EPI) in 2013 as a 3+0 schedule without catchup. We conducted three annual cross-sectional surveys from 2014-2016 to measure vaccine-type (VT) carriage in infants from a rural part of Pakistan. Nasopharyngeal specimens were collected by random sampling of infants from 2 union councils of Matiari. Samples were then transported to Infectious Disease Research Laboratory (IDRL) at the Aga Khan University within 6-8 hours of collection. Serotypes were established using sequential multiplex PCR. Of the 665 children enrolled across three surveys, 547 were culture positive for pneumococcus. VT carriage decreased from 21·8% in 2014 to 12·7% in 2016 (p-value for trend <0·001). Those who were not vaccinated or partially vaccinated were found to be at higher risk of carrying a VT serotype (aOR 2·53, 95% CI 1·39, 4·63 for non-vaccinated) and (aOR 3·35, 95% CI 1·82, 6·16 for partially vaccinated). On the other hand, being enrolled in the most recent survey was negatively associated with VT-carriage (aOR 0·51, 95% CI 0·28, 0·93). We found that PCV10 was effective in decreasing the carriage of vaccine-type serotypes in Pakistani infants.

Intrammary infections are a major problem for dairy sheep farms, and Streptococcus uberis is one of the main etiological agents of ovine mastitis. Surveys on antimicrobial resistance are still limited in sheep and characterization of isolates is important for acquiring information on resistance and for optimizing therapy. In this study, a sampling of 124 S. uberis isolates collected in Sardinia (Italy) from sheep milk was analysed by multilocus-sequence typing (MLST) and pulsed field gel electrophoresis (PFGE) for genetic relatedness. All isolates were also subjected to antimicrobial susceptibility analysis by the disk diffusion test using a panel of 14 antimicrobials. Resistance genes were detected by PCR assays. MLST analysis revealed that the isolates were grouped into 86 sequence types (STs), of which 73 were new genotypes, indicating a highly diverse population of S. uberis. The most frequently detected lineage was the clonal complex (CC)143, although representing only 13.7% of all characterized isolates. A high level of heterogeneity was also observed among the SmaI PFGE profiles, with 121 unique patterns. Almost all (96.8%) isolates were resistant to at least one antimicrobial, while all exhibited phenotypic susceptibility to oxacillin, amoxicillin-clavulanic acid and ceftiofur. Of the antimicrobials tested, the highest resistance rate was found against streptomycin (93.5%), kanamycin (79.8%) and gentamicin (64.5%), followed by novobiocin (25%) and tetracycline-TE (19.3%). Seventy-four (59.7%) isolates were simultaneously resistant to all aminoglycosides tested. Seventeen isolates (13.7%) exhibited multidrug resistance. All aminoglycosides-resistant isolates were PCR negative for aad-6 and aphA-3’ genes. Among the TE-resistant isolates, the tetM gene was predominant, indicating that the resistance mechanism is mainly mediated by the protection of ribosomes and not through the efflux pump. Three isolates were resistant to erythromycin, and two of them harboured the ermB gene. This is the first study reporting a detailed characterization of the S. uberis strains circulating in Sardinian sheep. Further investigations will be needed to understand the relationships between S. uberis genotypes, mastitis severity, and intra-mammary infection dynamics in the flock, as well as to monitor the evolution of antimicrobial resistance.

Streptococcus suis is a zoonotic pathogen causing serious infections in both swine and humans. Although metals are essential for life, excess amounts of metals they are toxic to bacteria. when accumulated in excess amounts. Except for zinc, Transcriptome-level data of the mechanisms for resistance to metal-induced toxicity in S. suis are available for no metals other than zinc. have not been investigated from the transcriptome level in S. suis. Herein, we explored the transcriptome-level changes of in S. suis in response to ferrous iron and cobalt toxicity by RNA sequencing. Many A lot of genes were differentially expressed in the presence of excess ferrous iron and cobalt. Most of the genes in response to cobalt toxicity showed the same expression trends as those were expressed in the same trend in response to ferrous iron toxicity. qRT-PCR analysis of the selected genes confirmed the accuracy of RNA sequencing results. Bioinformatics analysis of the differentially expressed genes indicated that ferrous iron and cobalt have similar impacts effects on the cellular processes of S. suis. Treatment with ferrous Ferrous iron treatment resulted in down-regulation of several oxidative stress tolerance-related genes involved in oxidative stress tolerance and up-regulation of the genes in an amino acid ABC transporter operon. Expression of the several genes in the arginine deiminase system was down-regulated in the presence of after ferrous iron and cobalt treatment. Collectively, our results suggested that S. suis alters the expression of a lot of multiple genes to respond to ferrous iron and cobalt toxicity.

Periodontal disease is that condition resulting in the destruction of periodontal tissues, bone re-sorption and tooth loss, the etiology of which is linked to immunological and microbiological factors. The aim of the study is to evaluate the potential trigger of periodontal disease in a rat model using the bacterial species incriminated in the pathology of human periodontitis and to establish their optimal concentration capable of reproducing the disease, with the idea of subsequently devel-oping innovative treatments for the condition. We included in the study 15 male Wistar rats, aged 20 weeks, which we divided into three groups. In each group, we applied ligatures with gingival retraction wire, on the maxillary incisors. 4 days/week, 4 weeks, the ligature and the gingival sac were contaminated with fresh cultures of Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum and Streptococcus oralis in concentrations of 108, 109 and 1010CFU/ml. The clinical monitoring period was 28 days, during which we followed the expression of clinical signs specific to periodontitis, the evolution of body weight and we took weekly samples from the oral cavity for the microbiological identification of the tested bacteria and blood samples for the hematological examination. At the end of the study, the animals were euthanized and the ligated incisors were taken for histopathological analysis. The characteristic symptomatology of periodontal disease was expressed from the first week of the study and was maintained until the end, the bacteria being able to be identified at each examina-tion. Hematologically, the number of neutrophils decreased dramatically (P<0.0001) in the case of group 109, unlike the other groups, as did the number of lymphocytes. Histopathologically, we identified neutrophilic infiltrate in all groups. The presence of coccobacilli, periodontal tissue hyperplasia and periodontal lysis, but in group 109 we also observed pulpal tissue with necrotic bone fragments and pyogranulomatous inflammatory reaction. By corroborating the data, we can conclude that for the development of periodontal disease using A.a, F.n and S.o, a concentration of 109 or 1010CFU/ml is required, which must necessarily con-taminate a ligature thread applied to the level of the rat's dental pack.

Among various metal-based nanoparticles, silver nanoparticles (AgNPs) manifest superior inhibitory effect against several microorganisms. In fact, the AgNPs based therapy has been reported to inhibit both sensitive as well resistant isolates of bacteria and other disease causing microbes with equal propensity. Keeping this fact into consideration, we executed bio-mediated synthesis of AgNPs employing Hibiscus rosa sinensis flower extract. The as-synthesized AgNPs were evaluated for their potential to inhibit Streptococcus mutans (S. mutans), one of the main causative bacteria for dental caries. Beside several other reasons, orthodontic appliances have also been reported to facilitate infliction of oral cavity with a range of microbes including S. mutans. To determine the growth inhibitory and anti-adherence activity of AgNPs on orthodontic appliance, we performed microbiological assays employing AgNPs adsorbed on to the orthodontic wires. Topographic analysis of orthodontic wires was executed by scanning electron microscopy. In addition to antimicrobial and antibiofilm activity against oral S. mutans, the as-fabricated AgNPs demonstrated significant inhibitory and anti-biofilm properties against other biofilm forming bacteria such as Escherichia coli and Listeria monocytogenes as well.

Consumption of refined foods and beverages high in sugar make the teeth susceptible to the formation of biofilm, and lead to dental caries and diseases of the oral cavity such as periodontitis and periodontal disease. The aim of the present study was to determine the ability of selected probiotics to inhibit growth and biofilm formation by the cariogenic bacterium Streptococcus mutans in vitro. We screened strains of latic acid bacteria (LAB) (n=120) from the Bioresources Collection and Research Center (BCRC), saliva of healthy adults and infant stool. The antimicrobial activity of LAB in vitro was evaluated by agar spot culture and co-culture of the S. mutans strains. We determined the effect of heating and dilution factors (2- and 4-fold) on the antagonistic activity of LAB. Antagonistic substances in the spent culture suspensions (SCS) of LAB were precipitated by extraction with ammonium sulphate and chloroform to characterise the protein and lipophilic fractions. Results of co-culturing show that the SCS of the three LAB strains (Lactobacillus pentosus 13-1, 13-4 and Lactobacillus crispatus BCRC 14618) subjected to heat treatment showed significantly high antimicrobial activity. We found that substances produced by L. pentosus 13-4 which have the potential to exhibit antimicrobial properties might be lipophilic proteins. Additionally, we infer that the mechanism of reducing biofilm formation by Lactobacillus strains is associated with sucrose-dependent cell–cell adhesion and the gtfC level of glucosyltransferases (Gtfs) in the biofilm. Native LAB strains screened in our study may be used in chewing gums and other processed foods for preventing tooth decay.

This mini-review deals with some non-starter lactic acid bacteria (NSLAB) species with a controversial nature known to be both human and animal pathogens but also health-promoting and probiotic. The focus is put on Lactococcus garvieae, two Streptococcus species (Str. uberis and Str. parauberis), four Weissella species (W. hellenica, W. confusa, W. paramesenteroides and W. cibaria) and Mammalicoccus sciuri which worldwide are often found within the microbiotas of different kinds of cheese, mainly traditional artisanal ones made from raw milk and/or relying on environmental bacteria for their ripening. Based on literature data, their virulence and health-promoting effects are examined, and some of the mechanisms of these actions are investigated. Additionally, their possible roles in cheese ripening are also discussed. The analysis so far showed that, in general, the pathogenic and the beneficial strains, despite belonging to the same species, show pretty different genetic constitutions. Yet, when the safety of a given strain is assessed, genomic analysis on its own is not enough, and a polyphasic approach is needed including additional physiological and functional tests.

To investigate the early immune responses and explore the optimal vaccination periods, Nile tilapia at 1, 7, 14, 21, 28, 35, and 42 days after yolk sac collapse (DAYC), were immersed in formalin-killed Streptococcus agalactiae vaccine (FKV-SA). The results found that specific IgM by ELISA in 21 DAYC (0.108 g) was first detected at 336 h after vaccination (hav), whereas 28-42 DAYC (0.330 - 0.580 g), could be initially detected at 24 hav. qRT-PCR analysis of the TCRβ, CD4, MHCIIα, IgHM, IgHT, and IgHD genes at 21- 42 DAYC immunized with FKV-SA immersion route for 24, 168 and 336 hav, revealed that most immune-related genes were significantly higher in the vaccinated larvae in all DAYCs than the control larvae (P &lt; 0.05) after 336 hav. Immunohistochemistry demonstrated the stronger signals of IgM in the gills, head kidney, and intestine tissues at 21, 28, and 35 DAYC were observed in all vaccinated larvae compared with the control. Interestingly, at all DAYCs, FKV-SA larvae exhibited significantly higher survival rates and an increased relative percent survival (RPS) than the control after challenge with viable S. agalactiae, particularly in larval fish that were immunized with FKV-SA for 168 and 336 hav (P &lt; 0.05).

Streptococcus suis serotype 2 is an important swine bacterial pathogen causing sudden death, septic shock, and meningitis. However, serotype 2 strains are phenotypically and genotypically heterogeneous and composed by a multitude of sequence types (STs) whose distribution greatly varies worldwide. It has been previously shown that lipoprotein (LPP) maturation enzymes diacylglyceryl transferase (Lgt) and signal peptidase (Lsp) significantly modulate the inflammatory host response and play a differential role in virulence depending on the genetic background of the strain. Differently from Eurasian ST1/ST7 strains, the capsular polysaccharide of a North American S. suis serotype 2 ST25 representative strain only partially masks sub-capsular domains and bacterial wall components. Thus, our hypothesis is that since LPPs would be more surface exposed in ST25 strains than in their ST1 or ST7 counterparts, the maturation enzymes would play a more important role in the pathogenesis of the infection caused by the North American strain. Using isogenic Δlgt and Δlsp mutants derived from the wild-type ST25 strain, our studies suggest that these enzymes do not seem to play a role in the interaction between S. suis and epithelial and endothelial cells, regardless the genetics background of the strain used. However, a role in the formation of biofilms (also independently of the STs) has been demonstrated. Moreover, the involvement of LPP dendritic cell activation in vitro seems to be somehow more pronounced with the ST25 strain. Finally, the Lgt enzyme seems to play a more important role in the virulence of the ST25 strain. Although some differences between STs could be observed, our original hypothesis that LPPs would be significantly more important in ST25 strains due to a better bacterial surface exposition could not be confirmed.

Streptococcus mutans (S. mutans) is the main etiological bacteria present in the oral cavity that leads to dental caries. All of the S. mutans in the oral cavity form biofilms that adheres to the surfaces of teeth. Dental caries are infections facilitated by the development of biofilm. An esterified derivative of epigallocatechin-3-gallate (EGCG), epigallocatechin-3-gallate-sterate (EGCG-S) was used in this study to assess its ability to inhibit the growth and biofilm formation of S. mutans. The effect of EGCG-S on bacterial growth was evaluated with colony forming units (CFU) and log reduction; biofilm formation was qualitatively determined by Congo red assay, and quantitatively determined by crystal violet assay, fluorescence-based LIVE/DEAD assays to study the cell viability, and scanning electron microscopy (SEM) was used to evaluate the morphological changes. The results indicated that EGCG-S was able to completely inhibit growth and biofilm formation at concentrations of 250 µg/ml. Its effectiveness was also compared with a commonly prescribed mouthwash in the United States, chlorhexidine gluconate. EGCG-S was shown to be equally effective in reducing S. mutans growth as chlorhexidine gluconate. In conclusion, EGCG-S is potentially a natural anticariogenic agent by reducing bacterial presence in the oral cavity.

The lactoperoxidase (LPO) system shows promise in the prevention of dental caries, a common chronic disease. This system has antimicrobial properties and is part of the non-specific antimicrobial immune system. Understanding the efficacy of the LPO system in the fight against biofilms could provide information on alternative strategies for the prevention and treatment of caries. In this study, the enzymatic system was modified using four different (pseudo)halide substrates (thiocyanate, thiocyanate-iodide mixture, selenocyanate, and iodide). The study evaluated the effects of such modifications on the ability of Streptococcus mutans to form a biofilm, the synthesis of insoluble polysaccharides, the synthesis of lactate, the consumption of glucose and sucrose, the concentrations of intracellular NAD+ and NADH and the efficiency of transmembrane glucose transport by phosphoenolpuryvate PEP-carbohydrate phosphotransferase (PTS). The results showed that the LPO-iodide system had the strongest inhibitory effect on biofilm growth and lactate synthesis (complete inhibition). This was associated with an increase in the NAD+/NADH ratio and an inhibition of glucose PTS activity. The LPO-selenocyanate system showed a moderate inhibitory effect on biofilm biomass growth and lactate synthesis. The other systems showed relatively small inhibition of lactate synthesis and glucose PTS but no effect on the growth of biofilm biomass. This study provides a basis for further research on the use of alternative substrates of the LPO system, particularly the LPO-iodide system, in the prevention and control of biofilm-related diseases.

Streptococcus pneumoniae is an pathogenic and opportunistic Gram-positive bacteria that is the leading cause of community acquired respiratory diseases, varying from mild- to deathly- infections. Appearance of antibiotic resistant isolates has prompted the search for novel targets. One of the most promising approaches is the structure-based knowledge of possible targets in conjunction to rational design and docking of inhibitors of the chosen targets. A useful technique to help solving protein structures is to label them with a heavy atom, like selenium, that facilitates tracing of the some of the amino acid residues. We have chosen two pneumococcal DNA-binding proteins, namely the relaxase domain of MobM protein from plasmid pMV158, and the RelB-RelE antitoxin-toxin protein complex. Through the update of a previous protocol [1] that uses seleno-L-methionine, we could achieve 100% labelling of the proteins. Furthermore, the labelled proteins retained full activity as judged from relaxation of supercoiled plasmid DNA and from gel-retardation assays.

Cellulose nanocrystals (CNCs) are cellulose-derived nanomaterials that can be easily obtained, e.g., from vegetable wastes produced by circular economies. They show promising antimicrobial activity and the absence of side effects and toxicity. This study investigated the ability of CNCs to reduce microbial adherence and biofilm formation using in vitro microbiological models reproducing the oral environment. Microbial adherence by microbial strains of oral interest, Streptococcus mutans and Candida albicans was evaluated on the surfaces of salivary pellicle-coated enamel disks in the presence of different aqueous solutions of CNCs. The antibiofilm activity of the same CNC solutions was tested against S. mutans and an oral microcosm model based on mixed plaque inoculum using a continuous-flow bioreactor. Results showed an excellent anti-adherent activity of the CNCs against the tested strains from the lowest concentration tested (0.032 wt.%). Such activity was significantly higher against S. mutans than C. albicans, suggesting a selective anti-adherent activity against pathogenic strains. At the same time, there was a minimal albeit significant antibiofilm activity (at least 0.5 and 4 wt.% CNC solution for S. mutans and oral microcosm, respectively). This makes CNCs particularly interesting as anticaries agents, encouraging their use in the oral field.

Streptococcus thermophilus is widely used as a starter culture in the dairy industry and has garnered attention as a beneficial bacterium owing to its health-promoting functionalities in humans. In this study, the probiotic potential of S. thermophilus MCC0200, isolated from a dairy product, was investigated through a combinatorial approach of in-vitro and in-silico studies. MCC0200 demonstrated the ability to survive harsh gastro-intestinal transit (GIT), adhere to intestinal mucosa and exert health-promoting traits in in-vitro studies. These findings were corroborated with in-silico evidence, wherein MCC0200 genome harboured genes associated with tolerance to GIT conditions, intestinal adhesion and colonization. Genome mapping also highlighted the ability of MCC0200 to produce compounds advantageous for host (folate, bacteriocins), to release enzymes that can reinforce the host ability (antioxidative enzymes), to metabolize food components that can be harmful to sensitive people (lactose). MCC0200 also demonstrated a positive effect on reducing cholesterol levels, proving to be a potential candidate for food and pharmaceutical applications. Absence of transmissible antibiotic resistance genes and virulence genes underscored the GRAS nature of MCC0200. This study explored the potential of Streptococcus thermophilus for its probable applications as a probiotic beyond the dairy industry.

Gamma-aminobutyric acid (GABA) is thought to have beneficial effects on human health and well-being. GABA enrichment by lactic acid bacteria (LAB) could be used in the development of functional fermented foods. In this work, four GABA-producing strains each of Lactococcus lactis and Streptococcus thermophilus were isolated from cowʼs milk, and their phenotypic, technological, and safety profiles were determined. Genome analysis provided genetic support for the majority of the analyzed traits. The operon harboring the glutamate decarboxylase gene (gadB) was chromosomally encoded in all strains and showed the same gene content and gene order as that reported, respectively, for L. lactis and S. thermophilus. In the latter species, the operon was flanked (as in most strains of this species) by complete or truncated copies of insertion sequences (IS), suggesting recent acquisition by horizontal gene transfer. The genomes of three L. lactis and two S. thermophilus strains showed a gene encoding a caseinolytic proteinase (PrtP in L. lactis and PrtS in S. thermophilus). These strains grew in milk forming a coagulum of good appearance and an appealing acidic flavor and taste. They also produced GABA from monosodium glutamate in this medium. Two L. lactis strains were identified as belonging to the biovar. diacetylactis, utilized citrate from milk and produced significant amounts of acetoin. None of the strains showed any noticeable antibiotic resistance, nor did their genomes harbor transferable antibiotic resistance genes, genes involved in toxicity, virulence, or pathogenicity. Altogether these results suggest all eight strains may be considered candidates for use as starter or components of mixed LAB cultures for the manufacture of GABA-enriched fermented dairy products.

This study aimed to assess the impact of different modes of laser irradiation on the bactericidal efficacy of aPDT. Dentin plates were prepared by sectioning the crown dentin of bovine teeth infected with Streptococcus sobrinus. Nine aPDTs involving the combinations of three photosensitizers (brilliant blue, BB; acid red, AR; and methylene blue, MB) and three laser irradiation modes (50 mW for 120 s, 100 mW for 60 s, and 200 mW for 30 s) were performed for each infected dentin plate, and the control group consisted of the specimens not applied with aPDT. The bactericidal effects in 10 experimental groups were evaluated (n=11) using both assays of the colony-count and adenosine triphosphate (ATP). The data obtained were analyzed using the Kruskal-Wallis test. The aPDT performed with semiconductor laser in combination with BB, AR, and MB exerted a remarkable bactericidal effect. aPDT with MB exerted a more significant bactericidal effect in the colony-count assay. The results of aPDT performed with varying irradiation times and powers but with constant irradiation energy showed no difference with AR and MB between the modes, whereas BB showed a more significant bactericidal effect when irradiated for a shorter time at a higher irradiation power.

Streptococcus mutans is well known for having virulence factors associated with its cariogenic role, such as glucosyltransferases, which have been used as targets for the virtual screening of molecules with inhibitory capacity. The Antigen I/II of S. mutans is involved in the adhesion to the surface of the tooth and the bacterial co-aggregation in the biofilm formation, despite that, this protein has not been used as a target in a virtual strategy search for inhibitors. In this study we identified in silico and evaluated in vitro molecules with adhesion inhibitory potential on S. mutans Ag I/II. A virtual screening of 883,551 molecules was conducted, cytotoxicity analysis on fibroblast cells, S. mutans adhesion studies, scanning electron microscopy analysis for bacterial integrity, and molecular dynamics simulation were also performed. We have found three molecules (ZI-187, ZI-939, ZI-906) that were not cytotoxic and inhibited the adhesion of S. mutans to polystyrene microplates. Molecular dynamic simulation by 300 nanoseconds showed stability of the interaction between ZI-187 and Ag I/II (PDB: 3IPK). This work provides three new molecules that targets Ag I/II and have the capacity to inhibit in vitro the S. mutans adhesion on polystyrene microplates and provides a new computational line for the search and selection of safe inhibitory molecules against different pathogens.

Streptococcus pneumoniae is one of the associated bacteria that can cause the rare but high mortality hematological disease known as purpura fulminans (PF) in both adults and children. Patients with PF can progress quickly to sepsis and multiorgan failure, especially in immunocompromised individuals and young children. Due to the thrombotic blockage of blood arteries in PF, there is diffuse intravascular thrombosis and hemorrhagic infarction of the skin, which evolves from ecchymosis to skin necrosis, risk of limb sequelae, sepsis and fatality. We present a case of a previously healthy 1-year and 9-month female who was admitted to the Intensive Care Unit of the National Institute of Infectious Diseases "Prof. Dr. Matei Balș"- Bucharest, Romania. The patient presented with erythematous patches on left upper limb and trunk, tachycardia, tachypnea, hypotension, anuria and altered sensorium with an indication of intubation for 8 Glasgow Coma Scale (GCS). Cerebrospinal culture grew Streptococcus pneumoniae serotype 1. She required peritoneal dialysis due to acute kidney injury (AKI) and surgeries for affected areas. After multiple organ system failures, our patient evolved rapidly to irreversible tissue necrosis and death. We aim to report a rare case of PF associated with pneumococcal meningoencephalitis in immunocompetent children to better appreciate the risk of fatal evolution when managing this disease in children. To date, few studies report favourable evolution. We discuss the etiology, rapid diagnosis and treatment of immunocompetent children with PF and the importance of interprofessional teams to increase the outcomes in patients with infectious diseases.

Using qRT-PCR analysis, the LcIL-8 expression level indicated broad expression in most detected tissues, with the most predominant expression in whole blood at 6 to 24 h after infection with S. iniae at concentrations of 105 colony-forming unit (CFU)/fish (p &lt; 0.05). After immersion with F. covae, the LcIL-8 transcript was upregulated in the gills, liver and intestine, with the highest expression level found in the gills. However, LcIL-8 was downregulated in all tested tissues at 48 and 96 h after infection with the two pathogenic strains, indicating that Lc-IL8 has a short half-life during the early immune responses to pathogens. MIC analysis of rLcIL-8 protein against S. iniae was 10.42 ± 3.61 µg/mL. Furthermore, the functional analyses clearly demonstrated that 10 and 100 µg of rLcIL-8 protein efficiently enhanced the phagocytic activity of Asian seabass phagocytes in vitro (p &lt; 0.05). Additionally, in vivo injection of S. iniae following the rLcIL-8 protein indicated that 50 and 100 µg of rLc-IL-8 were highly effective in protecting fish from the tested pathogen (p &lt; 0.001). These results indicate that rLcIL-8 plays a crucial role in the defense mechanisms against bacterial infections in the target fish.

The lactic acid bacteria Streptococcus thermophilus and Lactobacillus helveticus are commonly used as starter cultures in dairy product production. This study aimed to investigate the characteristics of fermented milk using different ratios of these strains and analyze the changes in volatile compounds during fermentation and storage. The 10:1 ratio of Streptococcus thermophilus CICC 6063 to Lactobacillus helveticus CICC 6064 showed optimal fermentation time (4.2 h), viable cell count (9.64 log10 colony-forming units/mL), and sensory evaluation score (79.1 points). In total, 56 volatile compounds were identified and quantified by solid-phase microextraction and gas chromatography–mass spectrometry (SPME-GC-MS), including aldehydes, ketones, acids, alcohols, esters, and others. Among these, acetaldehyde, 2,3-butanedione, 2,3-pentanedione, 2-heptanone, acetoin, and 1-heptanol had the highest odor activity values and contributed to the characteristic flavor of fermented milk. The concentrations and types of key flavor compounds reached their peak at the end of fermentation. Throughout the fermentation and storage process, the levels of 2,3-pentanedione and acetoin exhibited synergistic dynamics. These findings enhance our understanding of the chemical and molecular characteristics of milk fermented with Streptococcus thermophilus and Lactobacillus helveticus, providing a basis for improving the flavor and odor of dairy products during fermentation and storage.

Caries are lesions caused by acidic compounds derived from the metabolism of bacteria such as streptococci. It is not merely the presence of acidogenic bacteria that causes caries but an imbalance in the oral biofilm microhabitat and its behavior. One factor underlying biofilm formation is quorum sensing (QS), that in gram-positives relies on peptidic molecules, whereas in gram-negatives is driven by small diffusible signals. Strategies based on QS inhibition have been proposed as alter-natives to antimicrobial therapies. Here, we investigate the antibiofilm potential of the lactonase enzyme Aii20J, previously reported as effective against biofilms of periodontal disease origin. We generated in vitro polymicrobial biofilms dominated by gram-positive taxa using supragingival samples from caries-free and caries-active children. The effect of Aii20J on the biofilms was evalu-ated regarding its biomass-reducing ability, as assessed with crystal violet assay, and its effects on the bacterial composition of the polymicrobial biofilms, as assessed by 16S community profiling. We describe significant biomass reductions upon Aii20J exposure without significant changes in bac-terial composition at the genus level. Our results support the use of Aii20J to prevent oral biofilm formation while highlighting the influence of the polymicrobial environment on bacterial commu-nities and their response to antibiofilm treatments.

Here we report the preparation and characterization of a novel biomimetic toothpaste containing morphogenetically active amorphous polyphosphate (polyP) microparticles enriched with retinyl acetate (“a-polyP/RA-MP”). The spherical microparticles (average size, 550±120 nm), prepared by co-precipitating sodium-polyP with calcium chloride and supplemented with retinyl acetate, were incorporated into a basis toothpaste at a final concentration of 1% or 10%. The paste containing “a-polyP/RA-MP” significantly increased the growth of human mesenchymal stem cells (MSC), compared to a commercial toothpaste which acts rather inhibitory and the paste without polyP and retinyl acetate. qRT-PCR experiments revealed that the retinoid causes an induction of the expression of the MSC marker genes for osteoblast differentiation encoding collagen type I and alkaline phosphatase. On the other hand, the polyP ingredient, supplied as Zn-polyP microparticles (“Zn-a-polyP-MP”) strongly inhibited the growth of the cariogenic bacterium Streptococcus mutans. We demonstrate that the amorphous polyP-containing toothpaste, enriched with retinyl acetate, efficiently repairs both cracks/fissures and carious lesions in the tooth enamel, and reseals dentinal tubules, already after a 5 d treatment (brushing) of teeth twice daily for 5 min as examined by SEM and quantitative EDX analysis. The stability of the occlusion of dentin cracks even turned out to resist against short high power sonication treatment. Our results demonstrate that the novel toothpaste prepared here, containing amorphous polyP and retinyl acetate, is particularly suitable for prevention/repair of (cariogenic) damages of tooth enamel/dentin and for treatment of dental hypersensitivity.

Despite innovative advances in anti-infective therapies and vaccine development technologies, community-acquired pneumonia (CAP) remains the most persistent cause of infection-related mortality globally. Confronting the ongoing threat posed by Streptococcus pneumoniae (the pneumococcus), the most common bacterial cause of CAP, particularly to the non-immune elderly, remains challenging due to the propensity of the elderly to develop invasive pneumococcal disease (IPD), together with the predilection of the pathogen for the heart. The resultant development of often fatal cardiovascular events (CVEs), particularly during the first seven days of acute infection, is now recognized as a relatively common complication of IPD. The current review represents an update on the prevalence and types of CVEs associated with acute bacterial CAP, particularly IPD. In addition, it is focused on recent insights into the involvement of the pneumococcal pore-forming toxin, pneumolysin (Ply), in subverting host immune defenses, particularly the protective functions of the alveolar macrophage during early-stage disease. This, in turn, enables extra-pulmonary dissemination of the pathogen, leading to cardiac invasion, cardiotoxicity and myocardial dysfunction. The review concludes with an overview of the current status of macrolide antibiotics in the treatment of bacterial CAP in general, as well as severe pneumococcal CAP, including a consideration of the mechanisms by which these agents inhibit the production of Ply by macrolide-resistant strains of the pathogen.