Strains Of Streptococci Research Articles

Differential Study of Antimicrobial Activity of Vancomycin and Teicoplanin (Targocid) against Strains of Staphylococcus aureus and Streptococci sp.

The glycopeptide antibiotics vancomycin and teicoplanin (targocid) are widely used in the treatment of infections caused by gram positive bacteria. Vancomyc inhibits both transglycosylation and transpeptidation reaction during peptidoglycan assembly, targocid inhibits peptidoglycan polymerization, resulting in inhibition of bacterial cell wall synthesis and cell death. In this study twenty strains of streptococcus pyogenes and streptococcus pneumoniae and twenty five strains of staphylococcus aureus were collected from different infections. MI Cs and MBCs of vancomycin and targocid were determined against the bacterial strains, the MICs of vancomycin for the streptococcus strains were 4-8 µg /ml compared with 8-16 µg/ml for targocid and MI Cs of targocid for staphylococcus aureus were 4-16 µg/ml MBC for the same strains were 8-32 µg/ml. the conclusion of this study was that targocid was less active than vancomycin against staphylococci but equal or more active against streptococci specifically it presents excellent in vitro activity against streptococcus pneumonia strains.

Analysis of the clinical features and the risk factors of severe human metapneu movirus-associated community acquired pneumonia in children

Objective: To investigate the clinical characteristics and the risk factors of severe human metapneumovirus (hMPV)-associated community acquired pneumonia (CAP) in children. Methods: A retrospective case summary was conducted. From December 2020 to March 2022, 721 children who were diagnosed with CAP and tested positive for hMPV nucleic acid by PCR-capillary electrophoresis fragment analysis of nasopharyngeal secretions at the Yuying Children's Hospital, the Second Affiliated Hospital of Wenzhou Medical University were selected as the research objects. The clinical characteristics, epidemiological characteristics and mixed pathogens of the two groups were analyzed. According to CAP diagnostic criteria, the children were divided into the severe group and the mild group. Chi-square test or Mann-Whitney rank and contrast analysis was used for comparison between groups, while multivariate Logistic regression was applied to analyze the risk factors of the severe hMPV-associated CAP. Results: A total of 721 children who were diagnosed with hMPV-associated CAP were included in this study, with 397 males and 324 females. There were 154 cases in the severe group. The age of onset was 1.0 (0.9, 3.0) years, <3 years old 104 cases (67.5%), and the length of hospital stay was 7 (6, 9) days. In the severe group, 67 children (43.5%) were complicated with underlying diseases. In the severe group, 154 cases (100.0%) had cough, 148 cases (96.1%) had shortness of breath and pulmonary moist rales, and 132 cases (85.7%) had fever, 23 cases (14.9%) were complicated with respiratory failure. C-reactive protein (CRP) was elevated in 86 children (55.8%), including CRP≥50 mg/L in 33 children (21.4%). Co-infection was detected in 77 cases (50.0%) and 102 strains of pathogen were detected, 25 strains of rhinovirus, 17 strains of Mycoplasma pneumoniae, 15 strains of Streptococcus pneumoniae, 12 strains of Haemophilus influenzae and 10 strains of respiratory syncytial virus were detected. Six cases (3.9%) received heated and humidified high flow nasal cannula oxygen therapy, 15 cases (9.7%) were admitted to intensive care unit, and 2 cases (1.3%) received mechanical ventilation. In the severe group, 108 children were cured, 42 children were improved, 4 chlidren were discharged automatically without recovery and no death occurred. There were 567 cases in the mild group. The age of onset was 2.7 (1.0, 4.0) years, and the length of hospital stay was 4 (4, 6) days.Compared with the mild group, the proportion of children who age of disease onset <6 months, CRP≥50 mg/L, the proportions of preterm birth, congenital heart disease, malnutrition, congenital airway malformation, neuromuscular disease, mixed respiratory syncytial viruses infection were higher (20 cases (13.0%) vs. 31 cases (5.5%), 32 cases (20.8%) vs. 64 cases (11.3%), 23 cases (14.9%) vs. 44 cases (7.8%), 11 cases (7.1%) vs. 18 cases (3.2%), 9 cases (5.8%) vs. 6 cases (1.1%), 11 cases (7.1%) vs. 12 cases (2.1%), 8 cases (5.2%) vs. 4 cases (0.7%), 10 cases (6.5%) vs. 13 cases (2.3%), χ2=0.42, 9.45, 7.40, 4.94, 11.40, 8.35, 3.52, 6.92, all P<0.05). Multivariate Logistic regression analysis showed that age<6 months (OR=2.51, 95%CI 1.29-4.89), CRP≥50 mg/L (OR=2.20, 95%CI 1.36-3.57), prematurity (OR=2.19, 95%CI 1.26-3.81), malnutrition (OR=6.05, 95%CI 1.89-19.39) were the independent risk factors for severe hMPV-associated CAP. Conclusions: Severe hMPV-associated CAP is most likely to occur in infants under 3 years old and has a higher proportion of underlying diseases and co-infection. The main clinical manifestations are cough, shortness of breath and pulmonary moist rales, fever. The overall prognosis is good. Age<6 months, CRP≥50 mg/L, preterm birth, malnutrition are the independent risk factors for severe hMPV-associated CAP.

Whole microbe arrays accurately predict interactions and overall antimicrobial activity of galectin-8 toward distinct strains of Streptococcus pneumoniae

Microbial glycan microarrays (MGMs) populated with purified microbial glycans have been used to define the specificity of host immune factors toward microbes in a high throughput manner. However, a limitation of such arrays is that glycan presentation may not fully recapitulate the natural presentation that exists on microbes. This raises the possibility that interactions observed on the array, while often helpful in predicting actual interactions with intact microbes, may not always accurately ascertain the overall affinity of a host immune factor for a given microbe. Using galectin-8 (Gal-8) as a probe, we compared the specificity and overall affinity observed using a MGM populated with glycans harvested from various strains of Streptococcus pneumoniae to an intact microbe microarray (MMA). Our results demonstrate that while similarities in binding specificity between the MGM and MMA are apparent, Gal-8 binding toward the MMA more accurately predicted interactions with strains of S. pneumoniae, including the overall specificity of Gal-8 antimicrobial activity. Taken together, these results not only demonstrate that Gal-8 possesses antimicrobial activity against distinct strains of S. pneumoniae that utilize molecular mimicry, but that microarray platforms populated with intact microbes present an advantageous strategy when exploring host interactions with microbes.

Antioxidant and Antimicrobial Effects of Nannorrhops baluchestanica: An Endemic Palm Species in Southeast Iran

Background: Nannorrhops baluchestanica Khodash is a recently introduced shrubby species belonging to the family Arecaceae, distributed in Southeast Iran. Objectives: The antioxidant and antimicrobial potentials of this endemic plant were studied. Methods: The seeds and fruits of N. baluchestanica were collected from a natural population in Shark village, and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity of their hydroethanolic extracts was evaluated to determine potential antioxidant properties. In addition, inhibitory, bactericidal, and fungicidal effects of seed and fruit hydroalcoholic extracts were studied against a variety of pathogens, including three fungal strains (Aspergillus fumigatus, Fusarium oxysporum, and Candida albicans), three Gram-negative (klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli), and three Gram-positive bacterial strains (Bacillus cereus, Staphylococcus epidermidis, and Streptococcus pyogenes) via broth microdilution and streak plate methods. Results: The IC50 values of 26.20 and 33.90 µg.mL-1 were calculated for the fruit and seed extracts, respectively, using vitamin E with IC50 of 10.40 as standard. The MIC, MBC, and MFC values ranged from 128 to 2048 μg.mL-1. The fruit extract inhibited the growth of all microbial strains except for B. cereus and S. epidermidis, while P. aeruginosa and F. oxysporum were the only strains inhibited by the seed extract. In agreement with antioxidant properties, more broad-spectrum antimicrobial effects were observed in the fruit extract. Conclusions: Excellent antioxidant capacities of N. baluchestanica extracts indicate their great potential for treatment or prevention of oxidative stress-related diseases, but only slight effectiveness against infectious agents was observed.

Variable and insidious respiratory infections: can they be prevented?

In the practice of a pediatrician, among all detected infectious diseases, acute respiratory infections (ARI) continue to lead. The causes of respiratory infections can be varied. Great importance is attached to the normal microflora, as one of the main regulatory factors that can ensure the adaptation of children to different living conditions, and is responsible for maintaining homeostasis and maturation of the immune system. It has now been established that a healthy oral microbiome is the key to somatic health, and one of the important components of anti-infective protection. Therefore, one of the promising areas for the prevention of respiratory infections is the use of oral probiotics. The article provides an overview of findings from the studies on the efficacy and safety of the probiotic strain Streptococcus salivarius K12 showing inhibitory activities against the main respiratory pathogens – Streptococcus pyogenes, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis. S. salivarius K12 produces the bacteriocin-like inhibitory substance BLIS K12 (Bacteriocin-Like Inhibitory Substance), which plays an important role in maintaining the natural flora of the upper respiratory tract. It has been proven that the use of S. salivarius K12 results in a reduction of the level of pathogen colonization of the oropharyngeal mucosa, a rapid decline of the clinical symptoms of acute and chronic diseases of the ENT organs, and the prevention of acute respiratory diseases. The reason for this is that the intake of S. salivarius K12 increases the amount of interferon γ in saliva, stimulating the adaptive immunity against many viral infections. S. salivarius K12 is included in the clinical guideline on acute tonsillopharyngitis for the prevention of relapses, as well as the recovery of the normal biota of the oropharyngeal mucosa after disease.

Impact of using oat flour and erythritol on characteristics and glycemic index of chiffon cakes and study the effect of erythritol on cavity- causing bacteria

Oats have a high content of β-glucan. Its consumption lowers cholesterol and the glycemic response. One of the main components of many baked confectionery goods is sucrose. Reducing the amount of refined sugar in food has become urgently necessary as a result of the growing understanding of the link between excessive sugar consumption and the emergence of chronic diseases. Oat flour in the chiffon cake formulation was replaced at three levels, 50, 75 and 100% with wheat flour and had sucrose replaced with erythritol. Raw materials and prepared chiffon cake samples were analyzed for their chemical composition. Final product was evaluated for baking quality, glycemic index (GI) and organoleptic Properties of chiffon cake. The inhibitory effects of erythritol on Streptococcus strains were examined. Results suggest that, it could be seen that a significant increase in fiber and fat contents (10.1 and 6.52%, respectively) and a decrease in carbohydrate content 68.79%, in oat flour compared to wheat flour. Our results indicated that in the presence of erythritol was decreased the growth of S. sanguinis by 73%. Chiffon cake produced with oat flours and erythritol it was characterized with their higher content of moisture, ash and fiber. The highest weight (360.0 g) was given by adding 100% oat flour to the chiffon cake sample compared to 342.6 g for control cake. The GI were decreased as the levels of oat flour were increased and substituted sucrose with erythritol. Chiffon cakes prepared with 50% oat flour and 100% erythritol was decreased in sweetness

Antibacterial Activity of Tanacetum vulgare L. Extracts against Clinical Isolates of Bovine Mastitis

A bovine mastitis is an infectious disease, which is usually treated with antibiotics. Alternatively, herbal medicine has been proposed due to bacterial resistance. The aim of this study was to determine the antibacterial activity of the acetonic and ethanolic extracts of dried flowers and leaves of Tanacetum vulgare L. against bovine mastitis-inducing clinical isolates such as Escherichia coli, Streptococcus agalactiae, Streptococcus uberis, Serratia liquefaciens, Staphylococcus aureus, and reference cultures of S. aureus and E. coli. The extracts of T. vulgare showed partial antibacterial activity against tested strains of S. aureus. The MIC and MBC values of a 70% ethanol extract of flowers (MIC = 3.4 mg/mL, MBC = 3.4–6.8 mg/mL) were lower than for the 70% ethanol extract of leaves (MIC = 15.7–31.4 mg/mL, MBC = 62.9–125.9 mg/mL). The flower extracts showed low activity against E. coli (MIC = 53.9 mg/mL, MBC = 53.9–107.8 mg/mL) and S. agalactiae (MIC, MBC = 53.9 mg/mL). T. vulgare leaf extracts had minimal antibacterial effects against Streptococcus strains (MIC = 31.4–62.9 mg/mL, MBC = 53.9–125.9 mg/mL) and Serratia liquefaciens (MIC, MBC = 125.9 mg/mL). However, flower extracts had a higher phenolic content that did not correlate with antibacterial effects. T. vulgare flower and leaf extracts could be combined to obtain broader antibacterial effects.

Nigella sativa oil as a treatment for gingivitis

Objective: To assess the clinical anti-inflammatory and antimicrobial efficacy of Nigella sativa oil compared with chlorhexidine in patients with gingivitis. Methods: A double-blind, randomized clinical trial was conducted in patients having chronic generalized gingivitis. Patients were randomly assigned to receive Nigella sativa oil (n=18) or chlorhexidine (n=19). The following assessments were made on day 0 and day 15: plaque index, gingival index, gingival IL-6 and IL-18 levels were measured using ELISA, plaque colony-forming units, and alpha-hemolytic Streptococcus strains. Data were analyzed using parametric and non-parametric tests and Fisher's exact test. Results: Both interventions reduced plaque index and gingival index scores (P&lt;0.000 1). The Nigella sativa oil group was better at lowering IL-6 (P=0.0076) than the chlorhexidine group (P=0.145), although there was no change in IL-18 levels (P&gt;0.05). The post-intervention plaque index and gingival index scores and inflammatory cytokine levels between the two groups were not significantly different. Both interventions caused a significant reduction in the plaque colony-forming units (P&lt;0.0001), reducing pathogenic bacteria: Streptococcus mitis, Streptococcus oralis, Streptococcus sanguinis, and Streptococcus parasanguinis in the chlorhexidine group (50%) (P=0.103 1), and the Nigella sativa oil group (20%) (P=0.739 5). Conclusions: Nigella sativa oil had anti-inflammatory and antibacterial activities, reducing biofilm formation and disrupting the colonization of pathogenic bacteria essential for the progression of periodontal disease. Nigella sativa oil could offer an alternative therapy for treating gingivitis and may prevent associated systemic diseases and improve overall health outcomes.

Elucidating the role of N-acetylglucosamine in Group A Carbohydrate for the development of an effective glycoconjugate vaccine against Group A Streptococcus

Group A Carbohydrate (GAC), conjugated to an appropriate carrier protein, has been proposed as an attractive vaccine candidate against Group A Streptococcus infections. Native GAC consists of a polyrhamnose (polyRha) backbone with N-acetylglucosamine (GlcNAc) at every second rhamnose residue. Both native GAC and the polyRha backbone have been proposed as vaccine components. Here, chemical synthesis and glycoengineering were used to generate a panel of different length GAC and polyrhamnose fragments. Biochemical analyses were performed confirming that the epitope motif of GAC is composed of GlcNAc in the context of the polyrhamnose backbone. Conjugates from GAC isolated and purified from a bacterial strain and polyRha genetically expressed in E. coli and with similar molecular size to GAC were compared in different animal models. The GAC conjugate elicited higher anti-GAC IgG levels with stronger binding capacity to Group A Streptococcus strains than the polyRha one, both in mice and in rabbits.This work contributes to the development of a vaccine against Group A Streptococcus suggesting GAC as preferable saccharide antigen to include in the vaccine.

In Vitro Evaluation of Commercial Probiotic Products Containing Streptococcus salivarius K12 by Assessment of Probiotic Viability and Inhibitory Potency against Respiratory Pathogens

Upper respiratory infections (URI) are the most frequent illnesses, especially in children. The majority of those infections are prescribed broad-spectrum antibiotics, which are associated with various side effects and with the increase in multi-drug-resistant strains. A promising alternative approach is the administration of the probiotic strain Streptococcus salivarius K12 (SSK12) that colonizes the upper respiratory tract (URT) and produces the salivaricins A2 and B, which strongly antagonize the growth of key respiratory pathogens. However, since for food supplements no quality controls of the active probiotic ingredient are mandatory, the efficacy of commercial products containing SSK12 may vary. This study aimed to investigate the in vitro efficacy of several commercial SSK12-containing probiotics, positioned for the prevention of respiratory infections. The parameters evaluated to determine the in vitro efficacy included the viability of the probiotic bacterial strain and the minimum inhibitory dilution (MID) of the probiotic, determined by the agar spot method, against the pathogenic/potential pathogenic bacterial strains Streptococcus pyogenes FF22 and Micrococcus luteus T18. All tests were carried out both 12 and 24 months after manufacturing (AM) for each commercial product. The viability ranged from 9 × 108 to 4.4 × 109 CFU/serving at 12 months AM and from 8.5 × 107 to 2.8 × 109 CFU/serving at 24 months AM. The MID was, in general, positively correlated with the probiotic bacterium viability and varied between the commercial products, ranging from 10−5 to 10−7 at 12 months AM and from 10−4 to 10−7 at 24 months AM. Moreover, the inhibition zones related to the two indicator strains were variable in diameter for different products. The high variation of the in vitro efficacy of commercial products containing SSK12 may explain the different results reported in the literature regarding the clinical benefits of these preparations, and the determination of this parameter may be useful to evaluate the quality of probiotic products containing this bacterial strain.

Serotype Distribution and Antimicrobial Resistance of Streptococcus agalactiae Isolates in Nonpregnant Adults with Streptococcal Toxic Shock Syndrome in Japan in 2014 to 2021.

The incidence of streptococcal toxic shock syndrome (STSS) due to group B Streptococcus (GBS) has been increasing annually in Japan and is becoming a serious challenge. Furthermore, in recent years, penicillin- or clindamycin-resistant strains used in treating streptococcal toxic shock syndrome have been reported. However, no report analyzed >100 isolates of group B Streptococcus causing streptococcal toxic shock syndrome. Therefore, we aimed to perform serotyping and antimicrobial susceptibility testing of 268 isolated group B Streptococcus strains from streptococcal toxic shock syndrome cases involving nonpregnant adult patients in Japan between 2014 and 2021. The most prevalent serotype was Ib, followed by serotypes V, III, and Ia. Seven isolates were resistant to penicillin G, and 17.9% (48 isolates) were resistant to clindamycin. Of the penicillin-resistant group B Streptococcus isolates, 71.4% (5 isolates) were clindamycin resistant. In addition, group B Streptococcus strains resistant to penicillin and clindamycin were isolated from patients with streptococcal toxic shock syndrome. Therefore, before these strains become prevalent, introduction of the group B Streptococcus vaccine is essential for disease prevention. IMPORTANCE Group B Streptococcus (GBS) has been increasingly associated with invasive disease in nonpregnant adults. Such infections are responsible for substantial morbidity and mortality, particularly in individuals with underlying chronic conditions. Streptococcal toxic shock syndrome (STSS) is a severe invasive infection characterized by the sudden onset of shock, multiorgan failure, and high mortality. In this study, we assessed 268 GBS-related STSS cases in nonpregnant adults in Japan between 2014 and 2021. Serotype Ib was the most prevalent, followed by serotypes V, III, and Ia, which were identified in more than 80% of STSS isolates. We found that 48 clindamycin-resistant strains and 7 penicillin G-resistant strains were isolated between 2014 and 2021. We believe that our study makes a significant contribution to the literature because we show that the GBS vaccine, particularly the hexavalent conjugate vaccine, is important to reduce the number of patients with STSS.

Distribution of Multidrug-Resistant Invasive Serotypes of Streptococcus pneumoniae during the Period 2007-2021 in Madrid, Spain.

After the systematic use of conjugate vaccines, the invasive pneumococcal disease (IPD) was included into the Madrid Notifiable Diseases Surveillance System through an Epidemiological Surveillance Network. Furthermore, Streptococcus pneumoniae was included in the Spanish Plan of Antibiotic Resistance. The aim of this study was to analyse the multidrug-resistant (MDR) phenotype distribution among invasive strains of Streptococcus pneumoniae isolated during 2007-2021 from usually sterile clinical samples in Madrid, Spain. A total number of 7133 invasive pneumococcal isolates were studied during the period from February 2007 to December 2021. Serotyping was characterised using the Pneumotest-Latex and by the Quellung reaction. Antibiotic susceptibility testing to penicillin (PEN), erythromycin (ERY), and levofloxacin (LVX) was performed using the E-test according to the EUCAST guidelines and breakpoints. Combination of non-susceptibility to PEN at standard dosing regimen (PNSSDR), resistance to ERY (ERYR) and to LVX (LVXR) was considered to be multidrug-resistant at standard dosing regimen of penicillin (MRPSDR), whereas the combination of resistance to PEN (PENR), ERYR, and LVXR was considered multidrug-resistant (MDR). The number of MDRPSDR and or MDR strains in the entire population (n = 7133) during the complete period (2007-2021) were 51 (0.7%) and 6 (0.1%), respectively. All MDRPSDR and/or MDR strains belonged to nine serotypes: 19A (n = 13), 15A (n = 12), 9V (n = 12), 14 (n = 7), 24F (n = 3), 15F (n = 1), 19F (n = 1), 6B (n = 1) and 6C (n = 1). Only two serotypes (9V and 19A) were found among MDR strains, and most of them (5/6) belonged to serotype 9V. Only 12.4% of the strains typified as serotype 9V were MDRPSDR and only 5.2% as MDR. The levels of pneumococcal MDRPSDR and/or MDR in this study were low and all six MDR strains were isolated between 2014 and 2018. These results reinforce the importance of monitoring the evolution of non-susceptible serotypes including those with MDR in the coming years, especially after the introduction of new conjugate vaccines of a broader spectrum.

Multivariate analysis of structural and functional properties of fibres from apple pomace using different extraction methods

In recent years, diets rich in fibres have become more popular due to their well-documented beneficial health effects. This has driven exploration of novel dietary fibres from various bioresources. Apple pomace, an industrial waste rich in fibres was used in this study to extract the insoluble dietary fibres. The effect of various extraction methods (hot water, acid, and alkali) on the physico-chemical, structural and functional properties, and prebiotic activity of dietary fibres was evaluated. Hot water extraction resulted in highest yield of dietary fibres in comparison to other methods (p < 0.05). All the fractions resulted in different organization of fibrous components as depicted by scanning electron micrographs, Fourier Transform Infrared spectroscopy (FTIR), X-Ray Diffraction (XRD) pattern and Thermo Gravimetric Analysis (TGA). The acid extracted fibre fraction was observed to be amorphous with loose and porous structure whereas the alkali extracted fraction was more thermal stable based on TGA profile. Among the functional properties, acid extracted dietary fibres fraction possessed highest water and oil holding capacity (p < 0.05). The hot water extracted dietary fraction resulted in maximum increase in viable cell count of standard probiotic strains Lactobacillus sporogenes and Streptococcus faecalis. The Principal Component Analysis revealed that acid extracted fraction possessed better functional activity which also correlates with the structural properties whereas for prebiotic activities, the fibre obtained from hot water extraction method served the best method. These results indicate that dietary fibres extracted through hot water can be employed as a potential prebiotic substrate for the probiotic cultures and could be further explored in foods to improve textural, functional, and bioactive properties of foods.Graphical

Evolution of Antimicrobial Susceptibility to Penicillin in Invasive Strains of Streptococcus pneumoniae during 2007-2021 in Madrid, Spain.

The use of pneumococcal conjugate vaccines has affected the epidemiology and distribution of Streptococcus pneumoniae serotypes causing Invasive Pneumococcal Disease (IPD). The aim of this study was to analyze the evolution of the phenotypical profiles of antimicrobial susceptibility to penicillin (PEN) in all IPD strains isolated in Madrid, Spain, during 2007-2021. In total, 7133 invasive clinical isolates were characterized between 2007 and 2021. Levels of PENR and PNSSDR were 2.0% and 24.2%, respectively. In addition, 94.4% of all the PENR belonged to four serotypes, including 11A (33.6%), 19A (30.8%), 14 (20.3%) and 9V (9.8%). All the strains of serotype 11A, which is a non-PCV13 serotype, were detected after the year 2011. Serotypes 6C, 15A, 23B, 24F, 35B, 19F, 16F, 6B, 23F, 24B, 24A, 15F and a limited number of strains of serogroups 16 and 24 (non-typed at serotype level) were associated with PNSSDR (p < 0.05). PNSSDR strains of non-PCV13 serotypes 11A, 24F, 23B, 24B, 23A and 16F were more frequent from 2014 to 2021. The changes in S. pneumoniae serotype distribution associated with the use of conjugate vaccines had caused in our region the emergence of non-PCV13 pneumococcal strains with different PENR or PNSSDR patterns. The emergence of serotype 11A resistant to penicillin as the most important non-PCV13 serotype is a worrisome event with marked relevance from the clinical and epidemiological perspective.

449 - Phenotypic and genotypic changes over time in serotype iv group b streptococcus strains

449 - Phenotypic and genotypic changes over time in serotype iv group b streptococcus strains

Novel dithiocarbamate derivatives are effective copper-dependent antimicrobials against Streptococcal species.

Despite the availability of several vaccines against multiple disease-causing strains of Streptococcus pneumoniae, the rise of antimicrobial resistance and pneumococcal disease caused by strains not covered by the vaccine creates a need for developing novel antimicrobial strategies. N,N-dimethyldithiocarbamate (DMDC) was found to be a potent copper-dependent antimicrobial against several pathogens, including S. pneumoniae. Here, DMDCs efficacy against Streptococcal pathogens Streptococcus pyogenes, Streptococcus agalactiae, and Streptococcus anginosus was tested using bactericidal and inductively coupled plasma - optical emission spectrometry. After confirming DMDC as broad-spectrum streptococcal antimicrobial, DMDC was derivatized into five compounds. The derivatives' effectiveness as copper chelators using DsRed2 and as copper-dependent antimicrobials against S. pneumoniae TIGR4 and tested in bactericidal and animal models. Two compounds, sodium N-benzyl-N-methyldithiocarbamate and sodium N-allyl-N-methyldithiocarbamate (herein "Compound 3" and "Compound 4"), were effective against TIGR4 and further, D39 and ATCC® 6303™ _(a type 3 capsular strain). Both Compound 3 and 4 increased the pneumococcal internal concentrations of copper to the same previously reported levels as with DMDC and copper treatment. However, in an in vivo murine pneumonia model, Compound 3, but not Compound 4, was effective in significantly decreasing the bacterial burden in the blood and lungs of S. pneumoniae-infected mice. These derivatives also had detrimental effects on the other streptococcal species. Collectively, derivatizing DMDC holds promise as potent bactericidal antibiotics against relevant streptococcal pathogens.

Simultaneous adsorption and biodegradation of polychlorinated biphenyls using resuscitated strain Streptococcus sp. SPC0 immobilized in polyvinyl alcohol‑sodium alginate

Enhanced bioremediation of polychlorinated biphenyls (PCBs) is a promising and effective strategy for eliminating the risks posed by PCBs. In the present study, the feasibility of utilizing an immobilization approach to enhance the PCBs degradation performance of a resuscitated strain Streptococcus sp. SPC0 was evaluated. The results indicated that a mixed matrix containing polyvinyl alcohol (PVA) and sodium alginate (SA) used as immobilized carriers provided a porous microstructure space for SPC0 colonization and proliferation. The enhanced removal of PCBs by immobilized SPC0 was attributed to simultaneous adsorption and biodegradation performances of PVA-SA-SPC0 beads. The relative equilibrium adsorption capacity of immobilized beads increased with elevated initial concentration, and the maximum theoretical value calculated was 1.64 mg/g. The adsorption process of PCBs by immobilized beads was well fitted to the quasi-second-order kinetic model, and most suitable for Langmuir isotherm model. Immobilized SPC0 enhanced PCB removal with 1.0–7.1 times higher than free cells. Especially, more effective removal of PCBs at higher concentrations could be achieved, in which 73.9 % of 20 mg/L PCBs was removed at 12 h by immobilized SPC0, whereas only 12.0 % by free cells. Moreover, the immobilized SPC0 with excellent stability and reusability retained almost 100 % of the original PCBs removal activity after reusing four times. These results revealed the application potential of immobilizing resuscitated strains for enhanced bioremediation of PCBs.

Whole-Genome Sequences of Streptococcus alactolyticus Strain An1F4 and Escherichia coli Strains Ae3A3 and Ae3B3, Isolated from Feces of Domestic Pigs.

Here, we present the genome sequences of a strain of Streptococcus alactolyticus and two strains of Escherichia coli that were isolated from feces samples from domestic pigs in Denmark. The genome sequences contribute to a better understanding of the microbiological processes in the feces and manure of domestic pigs.

An Isolate of Streptococcus mitis Displayed In Vitro Antimicrobial Activity and Deleterious Effect in a Preclinical Model of Lung Infection.

Microbiota studies have dramatically increased over these last two decades, and the repertoire of microorganisms with potential health benefits has been considerably enlarged. The development of next generation probiotics from new bacterial candidates is a long-term strategy that may be more efficient and rapid with discriminative in vitro tests. Streptococcus strains have received attention regarding their antimicrobial potential against pathogens of the upper and, more recently, the lower respiratory tracts. Pathogenic bacterial strains, such as non-typable Haemophilus influenzae (NTHi), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus), are commonly associated with acute and chronic respiratory diseases, and it could be interesting to fight against pathogens with probiotics. In this study, we show that a Streptococcus mitis (S. mitis) EM-371 strain, isolated from the buccal cavity of a human newborn and previously selected for promising anti-inflammatory effects, displayed in vitro antimicrobial activity against NTHi, P. aeruginosa or S. aureus. However, the anti-pathogenic in vitro activity was not sufficient to predict an efficient protective effect in a preclinical model. Two weeks of treatment with S. mitis EM-371 did not protect against, and even exacerbated, NTHi lung infection.

Distribution of prophages in the Streptococcus bacteria genus and their role in increasing host pathogenicity

Bacteriophages are a category of viruses that only infect bacteria. Virulent phages cause the cell to produce new phages and lyse, while temperate phages remain in a latent state following phage lysogeny and integration of genetic material into the host genome as prophages. This integration enhances the genetic diversity of the host species, and the new genetic material may offer advantageous traits to aid the host’s survival and adaptation to new environments. Streptococcus bacteria are pathogens that infect both humans and animals, causing invasive infections and a diverse set of diseases. We hypothesized that strains of Streptococcus that have prophages present in their genome are linked to increased pathogenicity or antibiotic resistance. We used PhageWeb to identify prophages found within the 819 strains of Streptococcus genus from GenBank and the distribution of prophages across different species within the genus. With the Progressive Mauve software, we compared the sequences of identified prophages to determine similarities and relationships between the different prophages. Ultimately, based on information from gene ontology databases, we found that different prophages were associated with various virulence factors, adherence factors, and antibiotic resistance genes in their respective bacteria. Bacterial strains containing these prophages may have increased pathogenicity and the embedded genes could have a role in bacterial survivability in different environments. This genetic variation and these prophage characteristics shed light on the evolutionary dynamics of these bacteria species and can be applied to phage therapy.