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PURPOSE We describe a case of endophthalmitis caused by streptococcus salivarius presenting as a retinal vasculitis less than twenty-four hours after intravitreal injection. METHODS Case report RESULTS:: The patient progressed from a hemorrhagic retinal vasculitis to severe endophthalmitis with no view to the posterior segment within 24 hours. Visual acuity progressed from 20/20 pre-injection to light perception within less than 48 after injection. Vitreous tap and injection was performed within 24 hours of intravitreal aflibercept injection, followed by pars plana vitrectomy the next day. Final visual acuity was hand motions. CONCLUSIONS Streptococcus salivarius is a virulent organism that may cause an endophthalmitis early after intravitreal injection with an unusual presentation of hemorrhagic retinal vasculitis. A high index of suspicion for infectious endophthalmitis should be maintained for all patients presenting with ocular inflammation and worsening vision in the days following intravitreal injections.

Psoriasis is a common chronic skin disease, associated with an important physical and physiological involvement for any age. There is a strong link between psoriasis and streptococcal infection, particularly that of the tonsils. There are many therapies to treat psoriasis including topical, systemic, and biologic agents but these treatments are not free from side effects. Streptococcus salivarius K-12 is an oral probiotic product useful for the prophylaxis and treatment of tonsillar infections in children and adults, now tested here for the first time for control of psoriasis. Our retrospective analysis was conducted on 198 patients affected by mild to moderate psoriasis: 100 patients were first treated for 90 days with Streptococcus salivarius K-12, while 98 did not receive any probiotics and were the control group. The patients treated with S. salivarius K-12 exhibited a significant improvement of their psoriasis from the baseline condition: 83.7% patients treated achieved a 100% improvement of the PASI score at 24 weeks and efficacy continued to improve with longer treatment, maintaining same result also during follow-up observation. In all patients, the treatment was well tolerated, and no adverse events have been observed. Our data show that oral preparations containing Streptococcus salivarius may provide a beneficial option for the prevention and cure of pediatric and adult psoriasis.

The transmission of certain bacteria from the mother's gut to the infant's gut via breast milk (BM) is critical for offspring's immune system development. Dysbiosis of the BM microbiota can be caused by a variety of reasons, which can be influenced by probiotics delivered via the enteromammary route. The goal of this study was to investigate the bacterium that can be transmitted from mother to infant's intestine during various lactation periods in 19 mother-child dyads. Bacterial transmission is most common during the colostrum phase when bacteria with certain amplicon sequence variants (ASVs) enter the newborn intestine and inhabit it permanently. We have established that anaerobic gut-associated bacteria, such as Faecalibacterium, Blautia and Lachnoclostridium, transfer from the mother to the infant's gut with lactation dependence using the idea of weighted transfer ratios. Streptococcus salivarius, Bifidobacterium longum, and Lactobacillus gasseri were transferred from the maternal gut to the BM, as well as from the BM to the newborn gut, dependent on different ASVs. These findings suggest that isolating key microorganisms from breast milk could be utilized to modify the microbiota of BM or newborns by giving the mother a probiotic or adding it to artificial milk to promote neonatal health.

Competence is one of the most efficient bacterial evolutionary and adaptative strategies by synchronizing production of antibacterial compounds and integration of DNA released by dead cells. In most streptococci, this tactic is orchestrated by the ComRS system, a pheromone communication device providing a short time window of activation in which only part of the population is responsive. Understanding how this developmental process integrates multiple inputs to fine-tune the adequate response is a long-standing question. However, essential genes involved in the regulation of ComRS have been challenging to study. In this work, we built a conditional mutant library using CRISPR interference and performed three complementary screens to investigate competence genetic regulation in the human commensal Streptococcus salivarius. We show that initiation of competence increases upon cell wall impairment, suggesting a connection between cell envelope stress and competence activation. Notably, we report a key role for StkP, a serine-threonine kinase known to regulate cell wall homeostasis. We show that StkP controls competence by a mechanism that reacts to peptidoglycan fragments. Together, our data suggest a key cell wall sensing mechanism coupling competence to cell envelope integrity. IMPORTANCE Survival of human commensal streptococci in the digestive tract requires efficient strategies which must be tightly and collectively controlled for responding to competitive pressure and drastic environmental changes. In this context, the autocrine signaling system ComRS controlling competence for natural transformation and predation in salivarius streptococci could be seen as a multi-input device integrating a variety of environmental stimuli. In this work, we revealed novel positive and negative competence modulators by using a genome-wide CRISPR interference strategy. Notably, we highlighted an unexpected connection between bacterial envelope integrity and competence activation that involves several cell wall sensors. Together, these results showcase how commensal streptococci can fine-tune the pheromone-based competence system by responding to multiple inputs affecting their physiological status in order to calibrate an appropriate collective behavior.

This study sought to determine the prevalence of pathogenic and non-pathogenic bacteria in the oral cavities of children with cancer. There were 68 paediatric patients with cancer who were included in this study. Oral swab samples from the dorsum of tongues and mouth floors of these patients were subjected to culture, staining, and molecular methods to detect the bacteria. The overall prevalence of gram-positive and gram-negative bacteria was 79.4% (54/68; 95% CI = 68.4 - 87.3) and 25% (17/68; 95% CI = 16.2 - 36.4), respectively. Streptococcus salivarius and Streptococcus parasanguinis were the predominant pathogenic grampositive bacteria, while Neisseria subflava and Neisseria perflava were the most common pathogenic gram-negative bacteria. The results revealed that the number of bacteria isolates recovered in patients receiving cancer treatment was higher (55.9%) than those who had not received treatment (16.2%). Therefore, more isolated pathogenic bacteria were observed post-therapy (54.4%). Pathogenic organisms can have significant implications on patient health. Awareness of the types of bacteria inhabiting the oral cavity is essential to predict and prevent dental problems, and their associated systemic complications. Findings on the diversity of oral microflora can also provide a better understanding of the aetiology of oral diseases in paediatric patients receiving cancer treatment.

The gut microbiome is a vast reservoir of microbes, some of which produce antimicrobial peptides called bacteriocins that may inhibit specific bacteria associated with disease.

Previous studies have demonstrated the acrylamide-removing properties of probiotic monocultures; however, potential advantages of consortia over monocultures in reducing the dietary exposure to acrylamide have not been proven. Hence this work aims to assess the acrylamide (AA)-binding properties of bacterial consortia, consisting of either probiotic strains and / or representative bacteria of duodenal microbiota, exposed to simulated gastrointestinal conditions (SGC). The AA binding capacity of ten probiotic strains (PS) and six duodenal strains (NDS) was evaluated under different conditions; then, three different consortia (PS, NDS, and PS + NDS) were assessed under SGC.Among individual PS, Bacillus coagulans GBI-30, Lactobacillus fermentum J23, L. pentosus J37 and J24, and L. casei Shirota, exhibited the highest AA-binding capacity (80-87%), while Bifidobacterium catenulatun ATCC27676, Streptococcus salivarius subsp. thermophilus ATCC19258, and S. gallolyticus ATCC9809 were the best (ca. 68%) NDS monocultures. Probiotic strain consortia showed higher (P 0.05) AA binding capacity ( 90%) than monoculture bacteria. Conversely, individual NDS cultures displayed higher (P 0.05) binding capacity than NDS consortia (60%). A significant reduction (P 0.05) in AA removal capacity was observed when consortia were exposed to SGC, PS consortia being the most effective (60% removal).These results suggest that consortia of specific PS could play an important role in reducing the intestinal availability of acrylamide. © 2021 Society of Chemical Industry.

While the impact of oral microbiome dysbiosis on autoimmune diseases has been partially investigated, its role on bullous diseases like Pemphigus Vulgaris (PV) is a totally unexplored field. This study aims to present the composition and relative abundance of microbial communities in both healthy individuals and patients with oral PV lesions. Ion Torrent was used to apply deep sequencing of the bacterial 16S rRNA gene to oral smear samples of 15 healthy subjects and 15 patients. The results showed that the most dominant phyla were Firmicutes (55.88% controls-c vs 61.27% patients-p, p value = 0.002), Proteobacteria (9.17%c vs 12.33%p, p value = 0.007) and Fusobacteria (3.39%c vs 4.09%p, p value = 0.03). Alpha diversity showed a significant difference in the number of genera between patients and controls (p value = 0.04). Beta diversity showed statistical differences in the microbial community composition between two groups. Fusobacterium nucleatum, Gemella haemolysans and Parvimonas micra were statistically abundant in patients. We noticed the characteristic fetor coming out of oral PV lesions. Most of anaerobic bacteria responsible for oral halitosis are periopathogenic. Though, only F. nucleatum and P. micra were differentially abundant in our patients. Especially, F. nucleatum has been reported many times as responsible for bad breath. Furthermore, Streptococcus salivarius and Rothia mucilaginosa, species mostly associated with clean breath, were found in relative abundance in the healthy group. Consequently, the distinct malodor observed in PV patients might be attributed either to the abundance of F. nucleatum and P. micra and/or to the lower levels of S. salivarius and R. mucilanginosa in oral lesions.

BackgroundStaphylococcus aureusis a leading cause of healthcare- and community-associated infections and can be difficult to treat due to antimicrobial resistance. About 30% of individuals carryS. aureusasymptomatically in their nares, a risk factor for later infection, and interactions with other species in the nasal microbiome likely modulate its carriage. It is thus important to identify ecological or functional genetic elements within the maternal or infant nasal microbiomes that influenceS. aureusacquisition and retention in early life.ResultsWe recruited 36 mother-infant pairs and profiled a subset of monthly longitudinal nasal samples from the first year after birth using shotgun metagenomic sequencing. The infant nasal microbiome is highly variable, particularly within the first 2 months. It is weakly influenced by maternal nasal microbiome composition, but primarily shaped by developmental and external factors, such as daycare. Infants display distinctive patterns ofS. aureuscarriage, positively associated withAcinetobacterspecies,Streptococcus parasanguinis,Streptococcus salivarius, andVeillonellaspecies and inversely associated with maternalDolosigranulum pigrum. Furthermore, we identify a gene family, likely acting as a taxonomic marker for an unclassified species, that is significantly anti-correlated withS. aureusin infants and mothers. In gene content-based strain profiling, infantS. aureusstrains are more similar to maternal strains.ConclusionsThis improved understanding ofS. aureuscolonization is an important first step toward the development of novel, ecological therapies for controllingS. aureuscarriage.

The aim of this study was to detect oral bacteremia and offer the antibiotic resistance patterns. Bacterial resistance pattern was evaluated in 50 patients. A spectrophotometer device equipped with UV and electrophoresis of the extracted samples on agarose gel for antibiogram test were used. PCR test 15 minutes after tooth extraction showed that bacterial strains were extracted from 16 patients. Lactobacillus, Enterococcus faecalis (E. faecalis), Streptococcus sanguinis (S. sanguinis), Streptococcus salivarius (S. salivarius), and Streptococcus mutans (S. mutans) were extracted from 5, 4, 4, 4, and 6 patients. 100% of Lactobacillus, E. faecalis, S. sanguinis, S. salivarius, and S. mutans were sensitive to tigecycline. Most of the Lactobacillus antibiotic resistance was against tetracycline and ciprofloxacin. Antibiotic resistance in S. salivarius was observed in 75% of the cases against piperacillin-tazobactam, ciprofloxacin, and cefotaxime, while in S. mutans was 84% of the cases against ceftriaxone. The results of the current study showed that tooth extraction causes bacteremia before, during, and after tooth extraction. Generally, the highest antibiotic resistance occurred against tetracycline, ciprofloxacin, and ampicillin-sulbactam. In most cases, the bacteria showed partial resistance to these antibiotics; however, tigecycline showed 100% efficacy on all types of bacteria. Streptococcus strains (salivarius, mutans, and sanguinis) were sensitive to most of the antibiotics while antibiotic sensitivity was less evident in Lactobacillus and E. faecalis. Antibiotic resistance has become a critical issue, since it leads to treatment failure when there is a need for antibiotic therapy.

Although intestinal microbial dysbiosis was confirmed to be associated with many chronic diseases and health status through complicated interaction with the host, the effect on gastric cancer was less studied. In this study, we sequenced the 16S rRNA and 18S rRNA genes of fecal bacteria and fungi, respectively, in 134 gastric cancer patients and 58 healthy controls matched by age and gender. Propensity score matching (PSM) was adopted for adjusting diet habits and lifestyle, and 44 patients and 44 healthy controls (matching population) were enrolled. Serum antibody to H. pylori and metabolites of the matching population were detected. The positive rates of antibody to H. pylori between the patients and the control group did not reach the statistical difference. LEfSe analysis indicated that bacteria were more stable than fungi when adjusting diet and lifestyle. Veillonella, Megasphaera, and Prevotella 7 genus and Streptococcus salivarius subsp. Salivarius, Bifidobacterium dentium, and Lactobacillus salivarius species in bacteria were related to the risk of gastric cancer and showed a good diagnostic value in distinguishing the patients from healthy controls. Streptococcus mitis showed a risk effect for gastric cancer; however, the effect turned into be protective after PSM. Serum L-alanine, L-threonine, and methionol were positively associated with Veillonella and Streptococcus and several fungi genus. Overall, our findings indicated that fecal microbiome constitution alteration may be associated with gastric cancer through influencing the amino acid metabolism.

M18 strain of Streptococcus salivarius is a bacterial replacement probiotic that has been suggested for use in the oral cavity. Here, we have shown that S. salivarius M18 cell-free supernatant reduced the growth of the two most common human pathogens Pseudomonas aeruginosa and Klebsiella pneumonia and sensitized the pathogenic bacteria to antibiotic. Besides, the supernatant inhibited biofilm formation of P. aeruginosa drastically. For pinpointing the biomolecular changes that occurred in P. aeruginosa incubated with the probiotic supernatant, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy was used. Unsupervised learning algorithms, principal component analysis (PCA) and hierarchical cluster analysis (HCA), and intensity analyses of individual spectral bands exhibited comprehensive alterations in the polysaccharide and lipid contents and compositions of P. aeruginosa cultivated with S. salivarius M18 cell-free supernatant. These results indicate that S. salivarius M18 has the potential for the prevention or alleviation of different pathogen-induced infections along with the infections of oral pathogens.

Xerostomia detrimentally affects the oral health of many head and neck cancer patients who undergo radiotherapy. Its sequelae become an ongoing burden for patients that often manifest as periodontal disease and dental decay. Bacteria play a major role in the pathogenesis of these conditions and here we explore the use of an oral probiotic to beneficially modulate the oral bacterial community post-radiotherapy. In this pilot study, a four-week intervention with oral probiotic lozenges containing Streptococcus salivarius M18 was trialled in seven patients. Post-intervention changes in oral health and in the composition of the plaque and saliva bacterial communities were compared with six patients in a placebo group. An improvement in periodontal screening and plaque index scores was observed in both groups after the intervention period. The oral probiotic lozenges did not significantly impact bacterial community composition or diversity, nor did the probiotic lozenges increase the relative sequence abundance of ZOTU_1 (the probiotic-associated sequence assigned to S. salivarius) detected in the samples. Network analyses suggest negative interactions occurred between ZOTU_1 and species from the periopathogenic genera Campylobacter, Fretibacterium, Selenomonas and Treponema but further investigation is required to more fully understand the beneficial properties of this oral probiotic.

Lantibiotic salivaricins are polycyclic peptides containing lanthionine and/or β-methyllanthionine residues produced by certain strains of Streptococcus salivarius, which almost exclusively reside in the human oral cavity. The importance of these molecules stems from their antimicrobial activity towards relevant oral pathogens which has so far been applied through the development of salivaricin-producing probiotic strains. However, salivaricins may also prove to be of great value in the development of new and novel antibacterial therapies in this era of emerging antibiotic resistance. In this review, we describe the biosynthesis, antimicrobial activity, structure, and mode of action of the lantibiotic salivaricins characterized to date. Moreover, we also provide an expert opinion and suggestions for future development of this important field of microbiology.

Considering the implications of microbiota in health, scientists are in search of microbiota-oriented strategies for the effective prevention and/or treatment of a wide variety of serious diseases. A microbiota comprises diverse microorganisms with either probiotic or pathogenic properties. The fermentation of prebiotic carbohydrates by probiotic bacteria can affect host metabolism. Therefore, understanding the prebiotic-mediated metabolic modulations in probiotics is crucial to develop functional foods for the improvement of disturbed microbiota. Studies have emphasized the importance of prebiotics in probiotic therapies for mucosal diseases and highlighted the need for extensive research on oral bacteria. In the present study, the cellular events have been studied in batch cultures of probiotic Streptococcus salivarius exposed to the natural prebiotic, tapioca starch (TS). TS modulated the keystone metabolic events in Streptococcus salivarius in a dose-dependent manner. Besides increasing the live cell counts and altering the colony morphologies, TS affected the protein metabolism in terms of cellular expression and conformational changes in protein secondary structures. After treatment with TS, the nucleic acid synthesis increased and B-DNA was more than A- and Z-DNA, together with the diminished fatty acids and increased polysaccharide synthesis. The study results can be considered for the assessment of functional foods and probiotics in oral health.

The aim of this study was to evaluate the composition of microbiota of irreversible pulpitis and primary endodontic infections with respect to clinical and radiographic findings by performing cultures and 16s rDNA sequencing in Iranian patients. In this prospective cross-sectional study, samples were collected from 41 root canals for 4 main groups of patients. Bacterial identification was performed by the polymerase chain reaction (PCR) and 16s rDNA sequencing of aerobic and anaerobic cultivable colonies taken from patients’ culture plates. Additionally, the presence of 13 bacterial species and 3 nonbacterial species was also explored using PCR and species-specific primers. Sixteen microbial species, 1 fungus (Candida albicans), and 1 virus (Herpes simplex virus) were discovered and isolated. Species with the highest prevalence were Dialister invisus (68.3%), Porphyromonas gingivalis (58.8%), Streptococcus salivarius (58.5%), and Treponema denticola (56.1%). Lysinibacillus fusiformis (19.1%) was detected in the root canals for the first time. Candida albicans was seen in 11 cases (26.8%). Herpes simplex virus (HSV) was seen in 4 patients (9.8%). Our results suggest that Gram-negative anaerobic oral bacteria are the majority of the microbes in primary endodontic infections. Various combinations of bacterial species were related to different clinical and radiographic conditions. Lysinibacillus fusiformis was detected for the first time in primary endodontic infections. The results of this investigation might help clinicians choose to identify suspected endodontic pathogens in the etiology of each form of pulpal and periradicular diseases to determine the best therapeutic measures.

Background The aim of the study was to observe the antimicrobial activity of Porphyromonas gingivalis and Treponema denticola as well as the effect on reducing volatile sulfur compounds (VSCs). Materials and methods After P. gingivalis and T. denticola were cultured with or without Streptococcus salivarius K12 and M18, VSCs were measured by Oral Chroma. In order to analyze the mechanism for malodor control, the antimicrobial activity of S. salivarius K12 and M18 against P. gingivalis and T. denticola was assessed. SPSS 21.0 was used for data analysis with the Kruskal–Wallis and Jonckheere–Terpstra tests. Mann–Whitney test was applied for post hoc analysis. Results P. gingivalis and T. denticola VSC levels were reduced by high concentrations of S. salivarius K12 and M18 during coculture. The concentrations were lower than those of single culture (p < .05). An antimicrobial effect was detected on P. gingivalis, and T. denticola by 50% S. salivarius K12 and M18. The spent culture medium and whole bacteria of S. salivarius K12 and M18 reduced the levels of VSCs below the amount in a single culture of P. gingivalis and T. denticola (p < .05). Conclusion S. salivarius K12 and M18 decreased the levels of VSCs originating from P. gingivalis and T. denticola.

Aim The aim was to investigate the salivary detection frequencies and quantities of caries‐associated bacteria from patients with orthodontic brackets. Methods Patients wearing orthodontic brackets (n = 40, mean age = 26 years) and healthy controls without brackets (n = 40, mean age = 17 years) were enrolled in the study. Saliva samples from each patient was collected. After DNA purification, target species comprising streptococci and a Lactobacillus species were detected and quantified from the samples using polymerase chain reaction (PCR) and real‐time quantitative PCR. Results Detection frequencies did not differ between the orthodontic patients and the control subjects for any target species except for Streptococcus sobrinus, which showed significantly lower detection rates in orthodontic patients (p

Black extrinsic discoloration is a common clinical and aesthetic problem. This study aims to evaluate the potential in vitro antagonistic activity of two commercial probiotics, Streptococcus salivarius M18 and Lactobacillus reuteri ProDentis, against microorganisms associated with black stains. Streptococcus salivarius M18 and Lactobacillus reuteri were tested against Aggregatibacter actinomycetemcomitans and Actinomyces naeslundiiusing their cell-free fermentative broth in a planktonic growth inhibition test. Both probiotic cell-free supernatants showed the ability to reduce the pathogenic bacteria growth in a dose-dependent way. Streptococcus salivarius M18 showed a stronger antimicrobial activity than Lactobacillus reuteri ProDentis against the two indicator strains used. A. naeslundi was less susceptible to the probiotic activity of both S. salivarius and L. reuteri compared to A. actinomycetemcomitans. The obtained results demonstrate a potent antagonistic ability of probiotics to reduce the growth of microorganisms associated with black tooth stains. Therefore, these strains could be evaluated for a therapeutic use against dental pigmentations.

Antimicrobials have become a mainstay of healthcare in the past century due to their activity against pathogens. More recently, it has become clear that they can also affect health via their impact on the microbiota and inflammation. This may explain some of their clinical benefits despite global increases in antimicrobial resistance (AMR) and reduced antimicrobial effectiveness. We showed in a randomized controlled trial of stopping versus continuing cotrimoxazole prophylaxis among HIV-positive Zimbabwean children taking antiretroviral therapy (ART), that continuation of cotrimoxazole persistently suppressed gut-resident viridans group streptococcal species (VGS) that were associated with intestinal inflammation. In this addendum, we provide a broader overview of how antibiotics can shape the microbiota and use high read-depth whole metagenome sequencing data from our published study to investigate whether (i) the impact of cotrimoxazole on gut VGS and (ii) VGS associated inflammation, is attributable to strain-level variability. We focus on S. salivarius, the VGS species that was most prevalent in the cohort and for which there was sufficient genome coverage to differentiate strains. We demonstrate that suppression of S. salivarius by cotrimoxazole is not strain specific, nor did stool concentration of the pro-inflammatory mediator myeloperoxidase vary by S. salivarius strain. We also show that gut-resident S. salivarius strains present in this study population are distinct from common oral strains. This is the first analysis of how cotrimoxazole prophylaxis used according to international treatment guidelines for children living with HIV influences the gut microbiome at the strain-level. We also provide a detailed review of the literature on the mechanisms by which suppression of VGS may act synergistically with cotrimoxazole’s anti-inflammatory effects to reduce gut inflammation. A greater understanding of the sub-clinical effects of antibiotics offers new insights into their responsible clinical use.

Children with recurrent respiratory infections (RRI) represent a social issue for the economic burden and the familiar negative impact. Bacteriotherapy, such as the administration of “good” bacteria, is a new therapeutic strategy that could be potentially effective in preventing infections. The current study tested the hypothesis of preventing RRI by oral Bacteriotherapy in a real-life setting. This open study was conducted in an outpatient clinic, enrolling 51 children (27 males, mean age 4.8 ± 2.6 years) suffering from RRI. Children were treated with an oral spray, containing Streptococcus salivarius 24SMB and Streptococcus oralis89a (125 x 109 CFU/g), 2 puffs per os once/day for 30 consecutive days; this course was repeated for 3 months. The evaluated parameters were: RI number and school absences reported in the current year; these outcomes were compared with those recorded in the past year. The mean number of RI significantly diminished: from 5.17 (2.30) in the past year to 2.25 (2.43) after the treatment (p

We aimed to assess the effect of oral probiotics containing the Streptococcus salivarius K12 strain on the salivary level of secretory immunoglobulin A, salivation rate, and oral biofilm. Thirty-one consenting patients meeting the inclusion criteria were recruited in this double-blind, placebo-controlled, two-arm, parallel-group study and randomly divided into probiotic (n = 15) and placebo (n = 16) groups. Unstimulated salivation rate, concentration of salivary secretory immunoglobulin A, Turesky index, and Papillary-Marginal-Attached index were assessed after 4 weeks of intervention and 2 weeks of washout. Thirty patients completed the entire study protocol. We found no increase in salivary secretory immunoglobulin A levels and salivary flow rates in the probiotic group compared with placebo. Baseline and outcome salivary secretory immunoglobulin A concentrations (mg/L) were 226 ± 130 and 200 ± 113 for the probiotic group and 205 ± 92 and 191 ± 97 for the placebo group, respectively. A significant decrease in plaque accumulation was observed in the probiotic group at 4 and 6 weeks. Within the limitations of the present study, it may be concluded that probiotic intake (Streptococcus salivarius K12) does not affect salivation rates and secretory immunoglobulin A salivary levels but exhibits a positive effect on plaque accumulation. Trial registration NCT05039320. Funding: none.

In populations with similar prevalence of Helicobacter pylori infection, cancer risk can vary dramatically. Changes in composition or structure of bacterial communities in the stomach, either at the time of exposure or over the course of H. pylori infection, may contribute to gastric pathology. In this study, a population of 37 patients from the low-gastric-cancer-risk (LGCR) region of Tumaco, Colombia, and the high-gastric-cancer-risk (HGCR) region of Túquerres, Colombia, were recruited for gastric endoscopy. Antral biopsy specimens were processed for histology and bacterial isolation. Fifty-nine distinct species among 26 genera were isolated by aerobic, anaerobic, and microaerobic culture and confirmed by 16S rRNA analysis. Urease-positive Staphylococcus epidermidis and Streptococcus salivarius were frequently isolated from gastric biopsy specimens. We asked whether coinfection of H. pylori with urease-positive

The development of probiotics targeting non-intestinal body sites continues to generate interest amongst researchers, biotech companies and consumers alike. A key consideration for any bacterial strain to be developed into a probiotic is a robust assessment of its safety profile.

Approximately 25% of the world population suffer from halitosis, making it a significant medico-social issue. It is one of the clinical signs of chronic inflammatory diseases of the oropharynx and is commonly caused by the persistence some bacteria in the oral cavity and in the oropharynx. These in turn facilitate formation of volatile sulphur compounds.To evaluate the effectiveness and safety of the probiotic strain45 patients diagnosed with a diagnosis of exacerbation of chronic pharyngitis were studied, gastroesophageal reflux disease was found in 33 patients. After a microbiological testing, all patients were prescribed probiotic strainAccording to the microbiological analysis was revealed the growth ofTopical application of a drug containing a probioticГалитоз является важной медико-социальной проблемой, встречается примерно у 25% населения в мире, часто становится одним из основных клинических признаков хронических воспалительных заболеваний ротоглотки и возникает в результате образования летучих соединений серы в процессе жизнедеятельности ряда микроорганизмов полости рта и ротоглотки.Оценить эффективность и безопасность пробиотического штаммаПод наблюдением находились 45 пациентов с катаральным хроническим фарингитом; подтвержденный гастроэозофагеальный рефлюкс зарегистрирован у 33 человек в общей группе. После микробиологического исследования всем пациентам назначен пробиотический штаммПри микробиологическом исследовании у всех пациентов выявленыПодтверждена хорошая эффективность местного применения продукта, содержащего пробиотик

Poor taste and smell function are widely thought to contribute to the development of poor appetite and undernutrition in older adults. It has been hypothesized that the oral microbiota play a role as well, but evidence is scarce. In a cross-sectional cohort of 356 older adults, we performed taste and smell tests, collected anthropometric measurements and tongue swabs for analysis of microbial composition (16S rRNA sequencing) and Candida albicans abundance (qPCR). Older age, edentation, poor smell and poor appetite were associated with lower alpha diversity and explained a significant amount of beta diversity. Moreover, a lower Streptococcus salivarius abundance was associated with poor smell identification score, whereas high C. albicans abundance seemed to be associated with poor smell discrimination score. In our population, neither the tongue microbiota, nor C. albicans were associated with poor taste or directly with undernutrition. Our findings do suggest a host-microbe interaction with regard to smell perception and appetite.

The members of the infant microbiome are governed by feeding method (breastmilk vs. formula). Regardless of the source of nutrition, a competitive growth advantage can be provided to commensals through prebiotics - either human milk oligosaccharides (HMOs) or plant oligosaccharides that are supplemented into formula. To characterize how prebiotics modulate commensal - pathogen interactions, we have designed and studied a minimal microbiome where a pathogen, Streptococcus agalactiae engages with a commensal, Streptococcus salivarius. We discovered that while S. agalactiae suppresses the growth of S. salivarius via increased lactic acid production, galacto-oligosaccharides (GOS) supplementation reverses the effect. This result has major implications in characterizing how single species survive in the gut, what niche they occupy, and how they engage with other community members.

Streptococcus salivarius (S. salivarius) K12 supplementation has been found to reduce the risk of recurrent upper respiratory tract infections. Yet, studies have not reported the effect of supplementation on oral S. salivarius K12 levels or the salivary microbiome. This clinical trial was designed to determine how supplementation with S. salivarius K12 influences the oral microbiome. In a randomized, double-blind, placebo-controlled trial, 13 healthy adults received a probiotic powder (PRO) containing Lactobacillus acidophilus, Bifidobacterium lactis, and S. salivarius K12 and 12 healthy adults received a placebo-control powder (CON) (n = 12) for 14 consecutive days. Oral S. salivarius K12 and total bacteria were quantified by qPCR and the overall oral microbiome was measured using 16S rRNA amplicon sequencing. Supplementation significantly increased mean salivary S. salivarius K12 levels by 5 logs compared to baseline for the PRO group (p < 0.0005), which returned to baseline 2 weeks post-supplementation. Compared with the CON group, salivary S. salivarius K12 was 5 logs higher in the PRO group at the end of the supplementation period (p < 0.001). Neither time nor supplementation influenced the overall oral microbiome. Supplementation with a probiotic cocktail containing S. salivarius K12 for two weeks significantly increased levels of salivary S. salivarius K12.

Streptococcus salivarius K12 is an oral probiotic known to contribute to protection against oral pathogenic bacteria in humans. Studies of immune responses to S. salivarius K12 have focused on the oral cavity, and systemic immune responses have not yet been reported. The aim of this study was to identify acute systemic immune responses to the commercial product, S. salivarius BLIS K12, in a double-blinded, placebo-controlled human clinical trial. It was hypothesised that consumption of S. salivarius BLIS K12 would induce an anti-inflammatory response and a decrease in pro-inflammatory cytokines. Blood samples were obtained from participants prior to a single dose of S. salivarius BLIS K12 or a placebo and then secondary blood samples were obtained 24 h and 7 days post-consumption. Samples were analysed using multi-parametric flow cytometry, to quantify immune cell frequency changes, and by a LEGENDplex assay of human inflammatory cytokines. Consumption of S. salivarius BLIS K12 was associated with increased levels of IL-8 at 24 h. The frequency of Tregs increased in samples taken 7 days after probiotic consumption, and IL-10 concentrations were higher at 7 days than 24 h after consumption. There was no difference in the frequency and/or activation of CD4

BackgroundSore throat resulting from pharyngotonsillitis is one of the commonest reasons for primary care consultation and inappropriate antibiotic prescription and finding effective alternative treatments is important.ObjectivesTo review the evidence for using the probiotic Streptococcus salivarius K12 (SsK12) for the prevention or treatment of pharyngotonsillitis.Data SourcesPubMed, Embase, CINAHL and Cochrane Library.Study eligibility criteriaRandomized controlled trials (RCTs).ParticipantsAdults or children.InterventionsSsK12 as active treatment or prophylaxis, against pharyngotonsillitis.MethodsLiterature search.ResultsFour articles were identified (1846 participants). All were deemed to be of poor quality using the Cochrane risk-of-bias assessment. Two trials studied SsK12 prophylaxis for streptococcal pharyngitis (children without history of recurrence). One compared daily administration of SsK12 to no treatment over 6 months (n = 222, age 33–45 months), reporting significantly lower incidence in the SsK12 group (16.2% vs. 48.6%, p n = 1314, 5–14 years) found no significant difference (7.8% vs. 8.8%, p 0.34) with SsK12 (administered on school days). Another trial found daily SsK12 to significantly protect children (n = 250, 6–7 years) against chronic adenoiditis exacerbation over 3 months compared to no treatment (71.7% vs. 100%, p SsK12 for acute pharyngotonsillitis (concurrently with penicillin) showed no significant benefit. In all trials, SsK12 was safe and well tolerated.ConclusionsSsK12 appears safe and well tolerated. However, further RCTs are required to establish its role as a prophylactic therapy, particularly among patients experiencing frequent exacerbations of pharyngitis. In the acute setting, SsK12 is unlikely to be effective if given concurrently with antibiotics; however, further RCTs should establish its role as an alternative to antibiotics in nonsevere cases or when prescribed after antibiotic therapy for the prevention of disease recurrence and/or secondary infection.

AIM To investigate whether glycosaminoglycans (GAGs) binding to high-dose LL37 eliminates its cytotoxicity to dental pulp cells (hDPCs) whilst retaining undiminished antimicrobial and LPS-neutralizing abilities. METHODOLOGY hDPCs were stimulated with varying concentrations of LL37, and their cell viability was analysed by MTT. Then, high-dose LL37 (10 μmol L-1 ) was bound to varying concentrations of three GAGs, heparin, chondroitin sulphate and hyaluronic acid, and their cytotoxic effects on hDPCs and antimicrobial effects were evaluated and compared. Furthermore, the LPS-neutralizing ability of heparin (5 μg mL-1 )-LL37 (10 μmol L-1 ) complexes, which were found to be less cytotoxic for hDPCs with undiminished antimicrobial ability, was investigated. Statistical analysis was performed using one-way analysis of variance (anova), followed by Dunnett's test. P values below 0.05 were considered significant. RESULTS LL37 significantly reduced the cell viability of hDPCs in a dose-dependent manner (P

Direct antagonism towards pathogens including Streptococcus pyogenes is a proposed mechanism of pharyngeal probiosis but off-target effects on the symbiotic microbiota of the throat are possible and may be beneficial, harmful or neutral. We have assessed the bacteriological effects of two candidate Lactobacillus probiotics and the established pharyngeal probiotic Streptococcus salivarius K12. Antagonism towards S. pyogenes and potential off-target effects were determined using sessile monospecies biofilms and pharyngeal microcosms, respectively. The candidate probiotics were antagonistic towards S. pyogenes (rank order of increasing potency, Lactobacillus acidophilus < Lactobacillus plantarum < Streptococcus salivarius) in the absence of significant acidification or cell-cell contact. Streptococcus salivarius and L. plantarum caused significant reductions in viable counts of streptococci in pharyngeal microbiotas, whilst S. salivarius also caused reductions in staphylococci. In contrast, changes in pharyngeal eubacterial DNA profiles were limited overall. In summary, the three candidate probiotics suppressed axenic Streptococcus pyogenes biofilms by mechanisms that did not depend on cell-cell contact or acidification and did not markedly destabilize complex pharyngeal microbiotas derived from healthy individuals. SIGNIFICANCE AND IMPACT OF THE STUDY: Candidate probiotic bacteria deployed to prevent or treat bacterial pharyngitis will interact with the target bacteria such as Streptococcus pyogenes as well as with the microbiota of the throat, where off-target effects are possible. Three candidate probiotics Lactobacillus acidophilus, Lactobacillus plantarum and Streptococcus salivarius reduced viability within extant S. pyogenes biofilms through the elaboration of diffusible factors other than fermentation acids but did not markedly disrupt ex situ pharyngeal microcosms. This work demonstrates the application of in vitro pharyngeal models in the preclinical testing of the safety and efficacy of candidate pharyngeal probiotics.

Although the most common bacteria in the supragingival plaque are Gram-positive streptococci, no extensive investigations have been conducted into the susceptibility of these species to chlorhexidine and cetylpyridinium chloride. Therefore, in this study, we investigated the susceptibility of 80 streptococcal strains in planktonic or biofilm states to these two antimicrobial agents. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the planktonic streptococci were measured using the microdilution method, as were the minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC) measured on streptococcal biofilms formed on 96-well plates. In all species, the MIC, MBC, MBIC, and MBEC values were higher for chlorhexidine than for cetylpyridinium chloride, with sensitivity values varying according to species. For chlorhexidine, the MIC, MBC, and MBIC values showed statistically significant differences among species. However, only MBEC values showed statistically significant differences for cetylpyridinium chloride. The MIC against Streptococcus mutans and the MBC against Streptococcus salivarius were significantly lower than those against the other species. With he exception of a few species, most of the bacterium susceptibility values were higher in the biofilm state than in the planktonic state.

Previously, we showed that the growth, antibiotic resistance, and biofilm formation properties of the pathogens Pseudomonas aeruginosa and Klebsiella pneumonia were tremendously inhibited by the cell-free supernatant of the oral probiotic Streptococcus salivarius M18. These anti-pathogenic activities of the supernatant were more efficient under acidic conditions. The present approach takes advantage of the acidic nature of the tumor microenvironment to evaluate the effect of the S. salivarius M18 postbiotics on colon cancer cells. In both two-dimensional (2D) and three-dimensional (3D) cell culture models, S. salivarius M18 cell-free supernatant showed anti-cancer actions in the pH conditions mimicking the acidity of the tumor. The inhibitory effect was more prominent when the colon cancer cells have been treated with the cell-free supernatant obtained from the inulin incubated S. salivarius M18. The results of this study point out the potential of the S. salivarius M18 functional probiotic products to be used for targeting low pH environments including the unique acidic microenvironment of tumors.

Background Periodontal disease represents a major health concern. The administration of beneficial microbes has been increasing in popularity over efforts to manipulate the microbes using antimicrobial agents. This study determined the ability of Streptococcus salivarius to inhibit IL-6 and IL-8 production by gingival fibroblasts when activated by periodontal pathogens and their effect on the salivary microbiome. Methods Primary human gingival fibroblasts were challenged with Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum and a combination of all three. IL-6 and IL-8 cytokine release were measured. Using this same model, S. salivarius K12, M18 and different supernatant and whole-cell lysate fractions of S. salivarius K12 were administered to pathogen-induced fibroblasts. A patient study of healthy participants was also conducted to determine the effect S. salivarius K12 had on the native microbiome using 16S next generation sequence analysis. Results All pathogens tested induced a significant IL-6 and IL-8 response. S. salivarius K12 or M18, did not exhibit an increase in inflammatory cytokines. When either of the probiotic strains were co-administered with a pathogen, there were significant reductions in both IL-6 and IL-8 release. This effect was also observed when gingival fibroblasts were pre-treated with either S. salivarius K12 or M18 and then stimulated with the oral pathogens. Chewing gum containing S. salivarius K12 did not alter the salivary microbiome and did not increase inflammatory markers in the oral cavity. Conclusion S. salivarius K12 and M18 prevented immune activation induced by periodontal disease pathogens. S. salivarius K12 did not alter the salivary microbiome or induce immune activation when administered as a chewing gum. These results warrant further study to determine if it may be an effective treatment in a model of periodontal disease.

To improve our current understanding of normal flora in children, we investigated bacterial isolates from the pharynx and nasopharynx of 173 and 233 healthy children, respectively. The bacterial isolation rates were compared among three age groups: infants (

Aim Since the evolution of man, microbes are associated with humans, playing a vital role in the maintenance of good health. However, an imbalance in the gut microbial ecosystem is associated with several diseases including colorectal cancer. The supplementation of probiotics has been proven to be beneficial in improving colorectal cancer. In this study, we have evaluated the anti-cancer property of 11 probiotic strains on human colorectal carcinoma cell line (HCT-116). Methods and results In the present study, HCT-116 cells were treated with various concentrations (0.5, 5, 10, 20 and 200 million cfu ml-1 ) of probiotic strains and the viability was analysed by MTT assay and IC50 values were determined. Besides this, we evaluated the expression of multiple genes involved in the apoptosis and stress tolerance by real time PCR. Lactobacillus reuteri (UBLRu-87), Saccharomyces boulardii (Unique-28), Bacillus clausii (UBBC-07), B. coagulans (Unique-IS2) Streptococcus salivarius (UBSS-01), L. fermentum (UBLF-31), L. salivarius (UBLS-22), Bifidobacterium bifidum (UBBB-55) and L. plantarum (UBLP-40), exhibited potent cytotoxicity on HCT 116 cells. Furthermore, UBLF-31 and Unique-28 induced the expression of CJUN, CFOS and CASP-9, and down regulated the expression of BCL6. UBLRu-87 and UBBB-55 induced the expression of CJUN, CFOS and CASP-9 but not BCL-6. UBLP-40, UBBC-07, UBLS-22 and Unique-IS2 induced the expression of CJUN and CASP-9 and down regulated the expression of BCL-6. Conclusion These studies indicate the anti-cancer effects of selected probiotic strains by inducing apoptosis. Significance and impact of study The probiotic strains with the anti-cancer effects identified in the present study can be proposed as potential candidates in the treatment of colorectal cancers.

Aim. One of the main problems in dentistry is the injury caused by the long-term application of an ill-fitting denture. The existence of multiple microorganisms along with the susceptibility of the tissue conditioners to colonize them can lead to denture stomatitis. This study is aimed at developing a tissue conditioner incorporated with Carum copticum L. (C. copticum L.) for the effective treatment of these injuries. Materials and Methods. The Carum copticum L. essential oil composition was determined by gas chromatography-mass (GC-mass) spectrometry. The antimicrobial activity of the essential oil against the standard strains of bacterial and fungal species was determined by broth microdilution methods as suggested by the Clinical and Laboratory Standards Institute (CLSI). The physical and chemical properties of the prepared tissue conditioner were investigated by viscoelasticity, FTIR assays, and the release study performed. Furthermore, the antibiofilm activity of the Carum copticum L. essential oil-loaded tissue conditioner was evaluated by using the XTT reduction assay and scanning electron microscopy (SEM). Results. The main component of the essential oil is thymol, which possesses high antimicrobial activity. The broth microdilution assay showed that the essential oil has broad activity as the minimum inhibitory concentration was in the range of 32-128 μg mL-1. The viscoelasticity test showed that the essential oil significantly diminished the viscoelastic modulus on the first day. The FTIR test showed that Carum copticum L. essential oil was preserved as an independent component in the tissue conditioner. The release study showed that the essential oil was released in 3 days following a sustained release and with an ultimate cumulative release of 81%. Finally, the Carum copticum L. essential oil exhibited significant activity in the inhibition of microbial biofilm formation in a dose-dependent manner. Indeed, the lowest and highest amounts of biofilm formation on the tissue conditioner disks are exhibited in the Streptococcus salivarius and Candida albicans by up to 22.4% and 71.4% at the 64 μg mL-1 concentration of C. copticum L. with a statistically significant difference ( P < 0.05 ). Conclusion. The obtained results showed that the Carum copticum L. essential oil-loaded tissue conditioner possessed suitable physical, biological, and release properties for use as a novel treatment for denture stomatitis.

PLOS ONE 16(3), e0248308 (2021). doi:10.1371/journal.pone.0248308, Published by PLOS, San Francisco, California, US

The effect of xylitol tablets with (XPT) and without (XT) red propolis on salivary parameters, dental biofilm and acceptability of adolescents was evaluated through a blinded randomized crossover clinical trial. Healthy volunteers were allocated in the XPT and XT groups with a 30-day washout period for consumption of two tablets/dayfor seven days. An increase in salivary parameters was only observed immediately after tablet consumption, without differences between XPT and XT. The results for total microorganisms were similar, but XT was better in controlling Streptococcus spp. Rothia dentocariosa and Streptococcus salivarius were the most frequent in the biofilm and saliva, respectively. XPT and XT showed similar acceptability, with the highest purchase intention for XT. Although propolis did not enhance the properties of XT, further studies testing different protocols and follow-up are necessary; XT controlled Streptococcus spp. in biofilms, which demonstrate its potential for clinical application.

Aim This ex vivo study aimed to evaluate the of Er,Cr:YSGG laser effectiveness in the decontamination of an endodontic biofilm. Materials and methods Seventy-three single rooted human teeth, freshly were chosen. Each tooth was exposed to four associated species in an endodontic biofilm (Enterococcus faecalis, Streptococcus salivarius, Porphyromonas gingivalis, and Prevotella intermedia) and randomly allocated to one of the seven experimental groups. The group 1 (7 teeth) was used to finalize the reliable biofilm-forming technique. The groups 2 and 3 (15 teeth each group) were irradiated with two different Er;Cr:YSGG laser settings (0,75 W - 40 Hz and 4 W - 40 Hz, respectively). The groups 4 and 5 (15 teeth each group) were irrigated with two different solutions and laser irradiated with the same settings (1,5 W - 15 Hz). The group 6 (6 teeth) was the control group treated only with 4 ml 2,5% NaOCl irrigation during 60 s. Results The observations of group 2 and 3 specimens showed the ripeness of the biofilm with the presence of Enterococcus faecalis and Streptococcus salivarius in chains but in group 3 thermal edge effects produced by the optic fiber in the canal walls were present. The group 4 specimens observation showed an average cleaning of the root canal walls while on the canal walls of group 5 samples the apical third presented several debris and smear layer and in the centre cracks and melting dentin of the radicular wall were observed. Conclusion In those experimental conditions, this study, demonstrated that Er,Cr:YSGG laser has a canals decontamination ability when associated to NaOCl irrigation.

The microbiome which is developed at the time of infancy remains predominant and influences the health in childhood and then throughout life through moderating different gut metabolic activities This study was designed to look for the impact of feeding practices on the diversity of gut microbiota in infants in a Pakistani cohort.A cross sectional study was carried out in 46 healthy infants [23breast-fed (BF) and 23 formula-fed (FF)], aged 0-4 months, enrolled from different centers and localities in Peshawar. Infants were screened to exclude any pathological or physiological condition that can vary the gut microbial flora such as gut surgeries and the use of antibiotics. Their stool samples were collected. DNA was extracted and subjected to next generation sequencing.The results revealed that phylum Firmicutes was dominant in formula-fed infants (FF=25.4±22.7, BF=4.58±5.21), p=0.001. Similarly, Bacilli, Streptococcaceae, and Streptococcus were significantly higher in formula-fed infants. On the other hand, Selenomonadales and Streptococcus_salivarius were significantly higher in breast-fed infants with a p-value of 0.037 and 0.029 respectively when compared with formula fed infants.The primary colonizer of the infant's gut is phylum Firmicutes, followed by Bacilli, Streptococcaceae, and Streptococcus in formula-fed infants and Selenomonadales and Streptococcus_salivarius in breast-fed infants.

Genes encoding the subunits of the membrane-bound F1F0-ATPase (responsible for exporting protons from the cytoplasm and contributing to acid tolerance) were sequenced for 24 non-mutans streptococci isolated from carious lesions. Isolates, mostly Streptococcus salivarius, displayed a continuum of acid tolerance thresholds ranging from pH 4.55 to 3.39, but amino acid alignments of F1F0-ATPase subunits revealed few non-synonymous substitutions and these were unrelated to acid tolerance. Thus, the F1F0-ATPase is highly-conserved among S. salivarius isolates despite varying acid tolerance thresholds, supporting the contention that acid tolerance is determined by the level of gene/protein expression rather than variation in molecular structure.

Objective. Enterococcus faecalis and Streptococcus salivarius are the most important species in dental decay and producing biofilm. Treatment with chlorhexidine 2% mouthwash for 7 days is the best way to eliminate these bacteria. However, due to the ability of these bacteria to survive in harsh environments, increasing emergence of bacterial resistance against available antibiotics, and favorable properties of nanoparticles including broad spectrum antimicrobial activity and lower toxicity, we decided to evaluate reducing biofilm forming bacteria in oral cavity by bismuth nanoparticles. Materials and Methods. This was a cross-sectional study of 40 samples isolated from the patients visiting dental clinics in Shiraz in 2019. Samples, which showed growth, were cultured on blood agar plates and incubated for the PCR procedure. Nanoparticle powder was dissolved in high-purity water, and the final concentration of bismuth nanoparticles (BiNPs) was measured with a spectrophotometer. Minimum inhibitory concentration (MIC) of BiNPs against E. faecalis and S. salivarius was determined by the microbroth dilution method according to methods for antimicrobial susceptibility tests. Also, bactericidal assays were conducted in a Mueller-Hinton broth medium and reported as the concentration of BiNPs that reduced the viable bacterial count by 99.9%. Statistical analysis was carried out using SPSS 21 and one-way analysis of variance, andPvalues less than 0.05 were considered significant. Results. MICs of BiNP suspension against Streptococcus salivarius and Enterococcus faecalis were 2.5 and 5 μg/ml, respectively. Minimum bactericidal concentrations (MBC) of BiNP suspension against Streptococcus salivarius and Enterococcus faecalis were 5 and 10 μg/ml, respectively. Antibacterial activity of BiNPs was compared with chlorhexidine 2%. MICs of BiNPs against Streptococcus salivarius and Enterococcus faecalis were one-twentieth less than those of chlorhexidine. MBC of BiNPs against both pathogens was one-tenth less than those of chlorhexidine. Conclusion. BiNPs were more effective than chlorhexidine, and MIC and MBC of bismuth nanoparticles are lower than those of chlorhexidine.

Otitis media is a common childhood infection, frequently requiring antibiotics. With high rates of antibiotic prescribing and increasing antibiotic resistance, new strategies in otitis media prevention and treatment are needed. The aim of this study was to assess the in vitro inhibitory activity Streptococcus salivarius BLIS K12 against otitis media pathogens. Efficacy of the bacteriocin activity of S. salivarius BLIS K12 against the otitis media isolates was assessed using the deferred antagonism test. Overall, 48% of pathogenic isolates exhibited some growth inhibition by S. salivarius BLIS K12. S. salivarius BLIS K12 can inhibit the in vitro growth of the most common pathogens.

Children with recurrent respiratory infections (RRI) represent a social issue for the economic burden and the negative family impact. Local Bacteriotherapy is an attractive therapeutic strategy that could be potentially effective in preventing infections. The current article remarks on the existing evidence of preventing RRI by Local Bacteriotherapy.The literature search methodology was based on the articles cited by PubMed from 1980 to 2020. Respiratory infections include rhino-pharyngitis, otitis media, rhinosinusitis, pharyngo-tracheitis, bronchitis, and pneumonia. Several studies were performed to investigate the effects of Local Bacteriotherapy in children with RRI. Both intranasal and oral Local Bacteriotherapy were evaluated. The findings showed that Local Bacteriotherapy significantly reduced the number of RI episodes, their severity, the use of antibiotics, and school absences.Local Bacteriotherapy is a promising approach to RRI prevention and could be a profitable strategy to contrast infections in the future.

Viridans group streptococci (VGS) are a common cause of infective endocarditis, and dental plaque is the major source of these bacteria. The present study examined the antibiotic resistance of 635 VGS isolates obtained from dental plaques. Isolates from supragingival plaques were identified using the rapid ID 32 Strep and mini API reader (bioMerieux, France), and minimal inhibitory concentrations (MICs) were determined by a broth microdilution method. High rates of resistance to ampicillin and tetracycline were detected among the isolates. The most resistant species were Streptococcus sanguinis and Streptococcus salivarius. Among the 635 isolates, 9.1% were resistant to erythromycin, and 20.6% to tetracycline. All isolates were sensitive to vancomycin. Resistance to amoxicillin was observed in 0.2% of all isolates. In this study, we showed the incidence of antimicrobial resistance and the susceptibility patterns among 635 VGS isolates from dental plaque.