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Introduction: Streptococcus pyogenes is a Gram-positive pathogen that causes a significant global burden of skin pyoderma and pharyngitis. In some cases, infection can lead to severe invasive streptococcal diseases. Previous studies have shown that IL-17 deficiency in mice (IL-17-/-) can reduce S. pyogenes clearance from the mucosal surfaces. However, the effect of IL-17 on the development of severe invasive streptococcal disease has not yet been assessed. Methods: Here, we modeled single or repeated non-lethal intranasal (IN) S. pyogenes M1 strain infections in immunocompetent and IL-17-/- mice to assess bacterial colonization following a final IN or skin challenge. Results: Immunocompetent mice that received a single S. pyogenes infection showed long-lasting immunity to subsequent IN infection, and no bacteria were detected in the lymph nodes or spleens. However, in the absence of IL-17, a single IN infection resulted in dissemination of S. pyogenes to the lymphoid organs, which was accentuated by repeated IN infections. In contrast to what was observed in the respiratory mucosa, skin immunity did not correlate with the systemic levels of IL-17. Instead, it was found to be associated with the activation of germinal center responses and accumulation of neutrophils in the spleen. Discussion: Our results demonstrated that IL-17 plays a critical role in preventing invasive disease following S. pyogenes infection of the respiratory tract. [ABSTRACT FROM AUTHOR]

New rapid, reliable, and cost-effective alternative systems are needed for the rapid diagnosis of Streptococcus pyogenes. The aim of this study was to fabricate a microfluidic test device to detect Streptococcus pyogenes by combining the Loop-mediated isothermal amplification method via a 3D printer. Microfluidic test devices were designed in CATIA V5 Release 16 software, and data were directly transferred to a 3D printer and produced using the FDM method with biocompatible PLA filament. The S. pyogenes ATCC 19615 and different ATCC strains was used. Following identification by classical culture methods, a 0.5 McFarland suspension was prepared from the colonies, and DNA isolation was performed from this liquid by a boiling method. S. pyogenes specific speB gene was used to desing LAMP primer sets in PrimerExplorer V5 software and tested on a microfluidic device. LAMP reactions were performed on microfluidic device and on a microcentrifuge tube separately. Both results were analyzed using the culture method as the standard method to diagnostic values. Melting curve analysis of the amplicons of the LAMP reactions performed on a LightCycler 480 system to detect amplification. Among the 50 positive and 100 negative samples, only four samples were found to be false negative by LAMP reaction in a microcentrifuge tube, while eight samples were found to be false negative by LAMP reaction on a microfluidic device. Six samples were found to be false positive by the LAMP reaction in the microcentrifuge tube, while ten samples were found to be false positive by the LAMP reaction on a microfluidic chip. The sensitivity, specificity, positive predictive value, and negative predictive value of the LAMP reactions performed in the microcentrifuge tube and on the microfluidic device were 92–84%, 94–90%, 88.46–80.77%, and 95.92–91.84%, respectively. The limit of detection (LOD) was found to be the same as 1.5 × 102 CFU/mL and the limit of quantification (LOQ) values of the LAMP reactions were performed on the microcentrifuge tube and on the microfluidic device were 2.46 × 102–7.4 × 102 CFU/mL, respectively. Cohen's kappa (κ) values of the LAMP reactions were performed on the microcentrifuge tube and on the microfluidic device were 0.620–0.705, respectively. In conclusion, our data showed that the LAMP method can be combined with microfluidic test device to detect S. pyogenes, this microfluidic device can be manufactured using 3D printers and results are close to gold standard methods. These devices can be combined with LAMP reactions to detect different pathogens where resources are limited and rapid results are required. [ABSTRACT FROM AUTHOR]

Background: Streptococcus pyogenes is one of the major public health concerns causing human infections ranging from skin and throat infections to acute rheumatic fever and post streptococcal glomerulonephritis. Moreover, nowadays drug-resistant strains of S. pyogenes are emerging and can be transmitted through apparently healthy carriers to susceptible individuals. Objective: To assess the prevalence, antimicrobial susceptibility pattern and associated factors S. pyogenes among apparently healthy school children in Mekelle city primary schools, Northern Ethiopia. Methods: A cross-sectional study was conducted among 504 apparently healthy school children from February to May 2018. We used structured questionnaire to collect socio-demographic data. Throat specimens were collected using sterile cotton Swab and transported for culture, antimicrobial susceptibility and identification of S. pyogenes according to standard operating procedures. Data were analyzed using Stata 13 for descriptive statistics, bivariate and multivariate logistic regression. P-value

Streptococcal toxic shock syndrome (STTS) is a critical medical emergency marked by high morbidity and mortality, necessitating swift awareness, targeted treatment, and early source control due to its rapid symptom manifestation. This report focuses on a cohort of 13 patients admitted to Vall d'Hebron University Hospital Intensive Care Unit, Barcelona, from November 2022 to March 2023, exhibiting invasive Streptococcus pyogenes infections and meeting institutional sepsis code activation criteria. The primary infections were community-acquired pneumonia (61.5%) and skin/soft tissue infection (30.8%). All patients received prompt antibiotic treatment, with clinical source control through thoracic drainage (30.8%) or surgical means (23.1%). Organ support involved invasive mechanical ventilation, vasopressors, and continuous renal replacement therapy as per guidelines. Of note, 76.9% of patients experienced septic cardiomyopathy, and 53.8% required extracorporeal membrane oxygenation (ECMO). The study identified three distinct phenotypic profiles—hyperinflammatory, low perfusion, and hypogammaglobulinemic—which could guide personalized therapeutic approaches. STTS, with a mean SOFA score of 17 (5.7) and a 53.8% requiring ECMO, underscores the need for precision medicine-based rescue therapies and sepsis phenotype identification. Integrating these strategies with prompt antibiotics and efficient source control offers a potential avenue to mitigate organ failure, enhancing patient survival and recovery in the face of this severe clinical condition. [ABSTRACT FROM AUTHOR]

IntroductionStreptococcus pyogenes is a Gram-positive pathogen that causes a significant global burden of skin pyoderma and pharyngitis. In some cases, infection can lead to severe invasive streptococcal diseases. Previous studies have shown that IL-17 deficiency in mice (IL-17−/−) can reduce S. pyogenes clearance from the mucosal surfaces. However, the effect of IL-17 on the development of severe invasive streptococcal disease has not yet been assessed.MethodsHere, we modeled single or repeated non-lethal intranasal (IN) S. pyogenes M1 strain infections in immunocompetent and IL-17−/− mice to assess bacterial colonization following a final IN or skin challenge.ResultsImmunocompetent mice that received a single S. pyogenes infection showed long-lasting immunity to subsequent IN infection, and no bacteria were detected in the lymph nodes or spleens. However, in the absence of IL-17, a single IN infection resulted in dissemination of S. pyogenes to the lymphoid organs, which was accentuated by repeated IN infections. In contrast to what was observed in the respiratory mucosa, skin immunity did not correlate with the systemic levels of IL-17. Instead, it was found to be associated with the activation of germinal center responses and accumulation of neutrophils in the spleen.DiscussionOur results demonstrated that IL-17 plays a critical role in preventing invasive disease following S. pyogenes infection of the respiratory tract.

Surface-associated, coiled-coil M proteins of Streptococcus pyogenes (Strep A) disable human immunity through interaction with select proteins. However, coiled coils lack features typical of protein-protein interaction sites, and it is therefore challenging to understand how M proteins achieve specific binding, for example, with the human antimicrobial peptide LL-37, leading to its neutralization. The crystal structure of a complex of LL-37 with M87 protein, an antigenic M protein variant from a strain that is an emerging threat, revealed a novel interaction mode. The M87 coiled coil unfurled and asymmetrically exposed its hydrophobic core to capture LL-37. A single LL-37 molecule was bound by M87 in the crystal, but in solution additional LL-37 molecules were recruited, consistent with a 'protein trap' neutralization mechanism. The interaction mode visualized crystallographically was verified to contribute significantly to LL-37 resistance in an M87 Strep A strain and was identified to be conserved in a number of other M protein types that are prevalent in human populations. Our results provide specific detail for therapeutic inhibition of LL-37 neutralization by M proteins.

Staphylococcus aureus and Streptococcus pyogenes are the causative agents of cellulitis, a bacterial skin infection. Cellulitis primarily affects the skin, and it later spreads to the other parts of the body, especially through the lymph nodes and bloodstream. Without proper medication, it becomes life-threatening. The main symptoms include inflammation, tenderness, tight and swollen skin, and fever. Vaccines using epitopes as antigens trigger quick immune responses; in addition, they are cost effective. These antigens are derived from bacterial proteins. In this study, virulence factors from membrane proteins such as sak, tst, isdA, clfB, and can fromS. aureus (Fig. 1) and SPy, scpA, and hylp1 from S. pyogenes (Fig. 2) were selected for predicting the vaccine epitopes. VaxiJen server was used to evaluate the antigenicity of the selected proteins; BCPred, AAPPred, and ABCpred were used for B-cell epitope prediction, while ProPred and ProPred I were used for T-cell epitope prediction. MHCPred was used for the selected alleles, DRB1*0101 and DRB1*0401. Pepitope server was used for epitope mapping of the selected peptides. Epitopes that are common among those from BCPred, AAPPred, and ABCpred were selected: LKYGPKFDK (tst) and MTFDDKNGK (cna) from S. aureus and YTNSDKGGS (SPy), FKIEPDTTV (SPy), MTPSERLDL (scpA), VKTDDQQDK (scpA), and LKFKPAATV (hylp1) from S. pyogenes. Among them, YTNSDKGGS, MTPSERLDL, and MTFDDKNGK, were identified as suitable vaccine candidates for eliciting immune responses. These results of this study can be used to create a peptide-based vaccine for preventing cellulitis.

Molla Tadesse,1 Yohanes Hailu,2 Sirak Biset,3 Getachew Ferede,3 Baye Gelaw3 1Department of Medical Microbiology, Jigjiga University, Jigjiga, Ethiopia; 2Department of Pediatrics and Child Health, School of Medicine, University of Gondar, Gondar, Ethiopia; 3Department of Medical Microbiology, School of BioMedical and Laboratory Sciences, University of Gondar, Gondar, EthiopiaCorrespondence: Sirak Biset, Tel +251-911-598-568, Email serbis33@gmail.comBackground: Streptococcus pyogenes (S. pyogenes) or group A streptococcus is a common cause of bacterial pharyngitis in children. Since it is difficult to distinguish between viral and bacterial pharyngitis using solely signs and symptoms, culture-based diagnosis and treatment are critical for avoiding serious complications. Therefore, this study aimed to determine the prevalence, antimicrobial susceptibility patterns, and associated factors of S. pyogenes among pediatric patients with acute pharyngitis.Methods: A hospital-based cross-sectional study was conducted at the University of Gondar Comprehensive Specialized Hospital from April to June 2021. Standard microbiological procedures were used to collect and process throat swabs and to isolate and identify S. pyogenes. The disc diffusion method was used for antimicrobial susceptibility testing (AST).Results: A total of 215 children with acute pharyngitis were included in this study. Of these, 23 (10.7%) were culture positive for S. pyogenes. The presence of an inflamed tonsil, tonsillar exudate, scalariform rash, and dysphagia were associated with streptococcal pharyngitis. Children aged 5 to 15 were more susceptible to streptococcal throat infection than younger children. Penicillin, vancomycin, chloramphenicol, clindamycin, and ceftriaxone were effective against 100%, 95.7%, 95.7%, 91%, and 87% of isolates, respectively. In contrast, 56.5%, 39.1%, and 30.4% of isolates showed at least reduced susceptibility to tetracycline, erythromycin, and azithromycin, respectively.Conclusion: Streptococcus pyogenes is responsible for 10.7% of acute pharyngitis cases among pediatric patients in the study area. Although all isolates remain sensitive to penicillin, many showed reduced susceptibility to tetracycline and macrolides. Therefore, prior to antibiotic prescription, screening children with acute pharyngitis for S. pyogenes and testing the antibiotic susceptibility of isolates is recommended.Keywords: bacterial pharyngitis, S. pyogenes, group A streptococcus, antibiotic resistance, Ethiopia

CRISPR-Cas9 (clustered regularly interspaced short palindromic repeat and associated Cas9 protein) is a molecular tool with transformative genome editing capabilities. At the molecular level, an intricate allosteric signaling is critical for DNA cleavage, but its role in the specificity enhancement of the Cas9 endonuclease is poorly understood. Here, multi-microsecond molecular dynamics is combined with solution NMR and graph theory-derived models to probe the allosteric role of key specificity-enhancing mutations. We show that mutations responsible for increasing the specificity of Cas9 alter the allosteric structure of the catalytic HNH domain, impacting the signal transmission from the DNA recognition region to the catalytic sites for cleavage. Specifically, the K855A mutation strongly disrupts the allosteric connectivity of the HNH domain, exerting the highest perturbation on the signaling transfer, while K810A and K848A result in more moderate effects on the allosteric communication. This differential perturbation of the allosteric signal correlates to the order of specificity enhancement (K855A > K848A ~ K810A) observed in biochemical studies, with the mutation achieving the highest specificity most strongly perturbing the signaling transfer. These findings suggest that alterations of the allosteric communication from DNA recognition to cleavage are critical to increasing the specificity of Cas9 and that allosteric hotspots can be targeted through mutational studies for improving the system's function.

New rapid, reliable, and cost-effective alternative systems are needed for the rapid diagnosis of Streptococcus pyogenes. The aim of this study was to fabricate a microfluidic test device to detect Streptococcus pyogenes by combining the Loop-mediated isothermal amplification method via a 3D printer. Microfluidic test devices were designed in CATIA V5 Release 16 software, and data were directly transferred to a 3D printer and produced using the FDM method with biocompatible PLA filament. The S. pyogenes ATCC 19615 and different ATCC strains was used. Following identification by classical culture methods, a 0.5 McFarland suspension was prepared from the colonies, and DNA isolation was performed from this liquid by a boiling method. S. pyogenes specific speB gene was used to desing LAMP primer sets in PrimerExplorer V5 software and tested on a microfluidic device. LAMP reactions were performed on microfluidic device and on a microcentrifuge tube separately. Both results were analyzed using the culture method as the standard method to diagnostic values. Melting curve analysis of the amplicons of the LAMP reactions performed on a LightCycler 480 system to detect amplification. Among the 50 positive and 100 negative samples, only four samples were found to be false negative by LAMP reaction in a microcentrifuge tube, while eight samples were found to be false negative by LAMP reaction on a microfluidic device. Six samples were found to be false positive by the LAMP reaction in the microcentrifuge tube, while ten samples were found to be false positive by the LAMP reaction on a microfluidic chip. The sensitivity, specificity, positive predictive value, and negative predictive value of the LAMP reactions performed in the microcentrifuge tube and on the microfluidic device were 92–84%, 94–90%, 88.46–80.77%, and 95.92–91.84%, respectively. The limit of detection (LOD) was found to be the same as 1.5 × 102 CFU/mL and the limit of quantification (LOQ) values of the LAMP reactions were performed on the microcentrifuge tube and on the microfluidic device were 2.46 × 102–7.4 × 102 CFU/mL, respectively. Cohen’s kappa (κ) values of the LAMP reactions were performed on the microcentrifuge tube and on the microfluidic device were 0.620–0.705, respectively. In conclusion, our data showed that the LAMP method can be combined with microfluidic test device to detect S. pyogenes, this microfluidic device can be manufactured using 3D printers and results are close to gold standard methods. These devices can be combined with LAMP reactions to detect different pathogens where resources are limited and rapid results are required.

Group A Streptococcus (GAS) is a human-specific pathogen that evades the host immune response through the elaboration of multiple virulence factors. Although many of these factors have been studied, numerous proteins encoded by the GAS genome are of unknown function. Herein, we characterize a biomimetic red blood cell (RBC)-captured protein of unknown function-annotated subsequently as S protein-in GAS pathophysiology. S protein maintains the hydrophobic properties of GAS, and its absence reduces survival in human blood. S protein facilitates GAS coating with lysed RBCs to promote molecular mimicry, which increases virulence in vitro and in vivo. Proteomic profiling reveals that the removal of S protein from GAS alters cellular and extracellular protein landscapes and is accompanied by a decrease in the abundance of several key GAS virulence determinants. In vivo, the absence of S protein results in a striking attenuation of virulence and promotes a robust immune response and immunological memory.

Streptococcal toxic shock syndrome (STTS) is a critical medical emergency marked by high morbidity and mortality, necessitating swift awareness, targeted treatment, and early source control due to its rapid symptom manifestation. This report focuses on a cohort of 13 patients admitted to Vall d’Hebron University Hospital Intensive Care Unit, Barcelona, from November 2022 to March 2023, exhibiting invasive Streptococcus pyogenes infections and meeting institutional sepsis code activation criteria. The primary infections were community-acquired pneumonia (61.5%) and skin/soft tissue infection (30.8%). All patients received prompt antibiotic treatment, with clinical source control through thoracic drainage (30.8%) or surgical means (23.1%). Organ support involved invasive mechanical ventilation, vasopressors, and continuous renal replacement therapy as per guidelines. Of note, 76.9% of patients experienced septic cardiomyopathy, and 53.8% required extracorporeal membrane oxygenation (ECMO). The study identified three distinct phenotypic profiles—hyperinflammatory, low perfusion, and hypogammaglobulinemic—which could guide personalized therapeutic approaches. STTS, with a mean SOFA score of 17 (5.7) and a 53.8% requiring ECMO, underscores the need for precision medicine-based rescue therapies and sepsis phenotype identification. Integrating these strategies with prompt antibiotics and efficient source control offers a potential avenue to mitigate organ failure, enhancing patient survival and recovery in the face of this severe clinical condition.

Group A Streptococcus (GAS) remains one of the top 10 deadliest human pathogens worldwide despite its sensitivity to penicillin. Although the most common GAS infection is pharyngitis (strep throat), it also causes life-threatening systemic infections. A series of complex networks between host and pathogen drive invasive infections, which have not been comprehensively mapped. Attempting to map these interactions, we examined organ-level protein dynamics using a mouse model of systemic GAS infection. We quantified over 11,000 proteins, defining organ-specific markers for all analyzed tissues. From this analysis, an atlas of dynamically regulated proteins and pathways was constructed. Through statistical methods, we narrowed organ-specific markers of infection to 34 from the defined atlas. We show these markers are trackable in blood of infected mice, and a subset has been observed in plasma samples from GAS-infected clinical patients. This proteomics-based strategy provides insight into host defense responses, establishes potentially useful targets for therapeutic intervention, and presents biomarkers for determining affected organs during bacterial infection.

Variant calling is fundamental in bacterial genomics, underpinning the identification of disease transmission clusters, the construction of phylogenetic trees, and antimicrobial resistance detection. This study presents a comprehensive benchmarking of variant calling accuracy in bacterial genomes using Oxford Nanopore Technologies (ONT) sequencing data. We evaluated three ONT basecalling models and both simplex (single-strand) and duplex (dual-strand) read types across 14 diverse bacterial species. Our findings reveal that deep learning-based variant callers, particularly Clair3 and DeepVariant, significantly outperform traditional methods and even exceed the accuracy of Illumina sequencing, especially when applied to ONT's super-high accuracy model. ONT's superior performance is attributed to its ability to overcome Illumina's errors, which often arise from difficulties in aligning reads in repetitive and variant-dense genomic regions. Moreover, the use of high-performing variant callers with ONT's super-high accuracy data mitigates ONT's traditional errors in homopolymers. We also investigated the impact of read depth on variant calling, demonstrating that 10× depth of ONT super-accuracy data can achieve precision and recall comparable to, or better than, full-depth Illumina sequencing. These results underscore the potential of ONT sequencing, combined with advanced variant calling algorithms, to replace traditional short-read sequencing methods in bacterial genomics, particularly in resource-limited settings., Competing Interests: MH, RW, LJ, AN, ES, OX, MD, TS, TS No competing interests declared, LC Has received support from ONT to present his findings at scientific conferences; ONT played no role in study design, execution, analysis, or publication. Received research funding from ONT unrelated to this project, (© 2024, Hall et al.)

Background. Scarlet fever, an infectious disease caused by Streptococcus pyogenes, largely disappeared in developed countries during the twentieth century. In recent years, scarlet fever is on the rise again, and there is a need for a better understanding of possible factors driving transmission. Methods. Using historical case notification data from the three largest cities in The Netherlands (Amsterdam, Rotterdam and The Hague) from 1906 to 1920, we inferred the transmission rate for scarlet fever using time-series susceptible-infected-recovered (TSIR) methods. Through additive regression modelling, we investigated the contributions of meteorological variables and school term times to transmission rates. Results. Estimated transmission rates varied by city, and were highest overall for Rotterdam, the most densely populated city at that time. High temperature, seasonal precipitation levels and school term timing were associated with transmission rates, but the roles of these factors were limited and not consistent over all three cities. Conclusions. While weather factors alone can only explain a small portion of the variability in transmission rates, these results help understand the historical dynamics of scarlet fever infection in an era with less advanced sanitation and no antibiotic treatment and may offer insights into the driving factors associated with its recent resurgence.

Abstract Guava (Psidium guajava L.) leaf has long been the subject of diverse research initiatives as herbal medicine due to its antimicrobial activity against various bacteria. An Upper Respiratory Tract Infection (URTI) is a contagious infection of the upper respiratory tract, which can be caused by bacteria, i.e., Streptococcus pyogenes and Pseudomonas aeruginosa. In this research, guava leaves were extracted sequentially using solvents with different polarities. Furthermore, this research aimed to determine the antibacterial activity of guava leaf extract against URTI caused by bacteria (S. pyogenes and P. aeruginosa) and to formulate it into hard candy at various Minimum Inhibitory Concentrations (MIC), which were 2 MIC, 3 MIC, 4 MIC, and 5 MIC, to obtain hard candy with the highest antibacterial activity and organoleptic acceptability. To assist in the organoleptic acceptability aspect of the hard candy, lemongrass oil was used in varying concentrations (0%, 0.15%, 0.3%) as a flavoring agent. Results showed that ethanol guava leaf extract had the strongest antibacterial activity against both S. pyogenes (MIC=721.21 ppm) and P. aeruginosa (MIC=3085.91 ppm). Moreover, hard candy added with guava leaf extract at a concentration of 4 MIC and 0.15% lemongrass oil had the highest overall acceptability and antibacterial activity against S. pyogenes (inhibition diameter of 11.92 ± 0.56 mm) and P. aeruginosa (10.77 ± 0.69 mm).

Abstract Background Streptococcus pyogenes (S. pyogenes) is a Gram positive bacterium which is a leading cause of pharyngitis, skin and soft tissue infection and post streptococcal syndromes. Due to lack of β-lactamase enzyme production, it was considered universally susceptible to penicillin group and later generation of β-lactam antibiotics. As such, empirical treatment was common which might leads to development of antibiotics resistance. Therefore, the aims of this study were to determine the prevalence, antibiotics susceptibility profile; and associated factors of S. pyogenes among pediatric patients with acute pharyngitis in Felege Hiwot Comprehensive Specialized Hospital (FHCSH), Northwest Ethiopia. Methods Hospital based cross-sectional study was carried out on 154 pediatric patients, whose age ranged from 0 to 18 years old using consecutive convenient sampling technique from 1st February to 19th June 2020 at FHCSH. S. pyogenes were identified by throat swab culture on 5% sheep blood agar with an overnight incubation at 37 °C in candle jar containing 5% CO2. Gram stain, catalase test and bacitracin test were used to identify S. pyogenes. Then,the data were entered into EpiData version 3.1 and analyzed by SPSS version 20 software. Finally, stepwise, bivariable and multivariable logistic regressions were carried out for identifyying factors having significant ssociation (p

Numerous pathogens express arginine deiminase, an enzyme that catalyzes the hydrolysis of L-arginine in a chain of biochemical reactions aimed at the synthesis of ATP in bacterial cells. L-arginine is a semi-essential, proteinogenic amino acid that plays an important role in regulating the functions of the immune system cells in mammals. Depletion of L-arginine may cause a weakening of the immune reaction. In order to improve the conditions of dissemination, many pathogens use a strategy of L-arginine depletion in the microenvironment of host cells. Bacterial arginine deiminase can be a pathogenicity factor aimed for dysregulating the processes of inflammation and immune response. In general, the effect of arginine deiminase on immune cells may result into disturbed production of regulatory proinflammatory molecules, such as NO, and related substances, inhibition of activation, migration and differentiation of individual leukocyte subsets. The aim of this study was to investigate the effect of arginine deiminase on the formation of inflammatory infiltrate in murine air pouch model of streptococcal infection. Materials and methods: The study was performed using S. pyogenes M49-16 expressing arginine deiminase and its isogenic mutant S. pyogenes M49-16delArcA with inactivated arginine deiminase gene. The flow cytometry analysis of the inflammatory infiltrate leukocytes subpopulation in mice infected with the original strain of S. pyogenes M49-16 and its isogenic mutant S. pyogenes M49-16delArcA at different periods of infection was performed. It was shown that the inflammation reached its peak 6 hours after streptococcal inoculation, being more pronounced in mice infected with the mutant strain. Тhis finding was affirmed by a simultaneous and more pronounced increase in the absolute numbers of all leukocyte subsets in the focus of inflammation in this group of mice when compared to mice infected with original bacterial strain. Despite the decrease in the absolute number of all leukocyte types in the inflammatory infiltrate in both groups of mice for 24 hours, this trend was more pronounced in the group of mice infected with mutant microbial strain. Comparison of the inflammatory infiltrates developing in mice infected with original versus mutant strains showed that arginine deiminase may be a pathogenicity factor leading to dysregulation of protective immune response, due to impaired migration of white blood cells to the site of infection.

Background: Streptococcus pyogenes is one of the major public health concerns causing human infections ranging from skin and throat infections to acute rheumatic fever and post streptococcal glomerulonephritis. Moreover, nowadays drug-resistant strains of S. pyogenes are emerging and can be transmitted through apparently healthy carriers to susceptible individuals., Objective: To assess the prevalence, antimicrobial susceptibility pattern and associated factors S. pyogenes among apparently healthy school children in Mekelle city primary schools, Northern Ethiopia., Methods: A cross-sectional study was conducted among 504 apparently healthy school children from February to May 2018. We used structured questionnaire to collect socio-demographic data. Throat specimens were collected using sterile cotton Swab and transported for culture, antimicrobial susceptibility and identification of S. pyogenes according to standard operating procedures. Data were analyzed using Stata 13 for descriptive statistics, bivariate and multivariate logistic regression. P -value <0.05 was declared statistically significance., Results: The mean age of the study participants was 11.5 years of which 55 % of them were females. The overall prevalence of S. pyogenes was 8.3 %. Being female, having low monthly income, weak personal hygiene, poor hand washing habit and crowded living style were significantly associated with the occurrence of S. pyogenes . The isolates of S. pyogenes showed resistance to Penicillin (69.1 %), Amoxicillin-Clavulanic acid (62 %), Ampicillin (54.6 %), Ceftriaxone (47.6 %), Tetracycline (14.4 %), Cefoxitin (7.2 %). About 57.15 % isolates were multidrug-resistant., Conclusions: This study revealed that some isolates of S. pyogenes among the apparently healthy school children were resistant to commonly prescribed antibiotic agents and associated with hygienic conditions and living style. Therefore, it is recommended to practice antimicrobial susceptibility test to maintain rational antibiotic use and improve hygienic and hand washing practices to decrease the likelihood of carriage rate., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Previous studies have clearly demonstrated that the addition of lentisk oil (LO) to streptococcal cultures makes it possible to differentiate Streptococcus spp. into three categories with Streptococcus mitis and Streptococcus intermedius sensitive, Streptococcus pyogenes, Streptococcus agalactiae, and Streptococcus mutans partially sensitive, and Streptococcus salivarius insensitive to the product. We have investigated here whether the winterization of LO, an easy and cheap procedure that removes some of the fatty substances contained within, resulted in a better antimicrobial effect on human pathogens affecting the pharyngeal mucosa and middle ear such as S. pyogenes, S. pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae, without affecting, or minimally affecting, S. salivarius strains, oral probiotics commonly used to reduce oral and middle ear infection recurrence, especially in children. Our results not only demonstrated a stronger antimicrobial action of winterized LO (WLO) on S. pyogenes, compared to what was seen with LO, but also demonstrated a strong antimicrobial action vs. S. pneumoniae and M. catarrhalis and a very limited effect on S. salivarius (strains K12 and M18). Moreover, WLO demonstrated a co-acting action when tested along with the antibiotics amoxicillin (A) and amoxicillin clavulanate (AC), effects clearly visible also on H. influenzae. Our results also showed that at least part of the antimicrobial effect observed was due to the presence of anacardic acids (AAs). Finally, WLO, when tested with human peripheral blood mononuclear cells (h-PBMCs), reduced the release of IL-6 and TNF-α and, in the case of cells stimulated by LPS, the release of IFN-γ. In conclusion, our study highlights an enhanced antimicrobial role for LO when winterized, suggests a co-acting effect of this when given with antibiotics, identifies AAs as possible active ingredients, and proposes a possible anti-inflammatory role for it.

Previous studies have clearly demonstrated that the addition of lentisk oil (LO) to streptococcal cultures makes it possible to differentiate Streptococcus spp. into three categories with Streptococcus mitis and Streptococcus intermedius sensitive, Streptococcus pyogenes , Streptococcus agalactiae , and Streptococcus mutans partially sensitive, and Streptococcus salivarius insensitive to the product. We have investigated here whether the winterization of LO, an easy and cheap procedure that removes some of the fatty substances contained within, resulted in a better antimicrobial effect on human pathogens affecting the pharyngeal mucosa and middle ear such as S. pyogenes , S. pneumoniae , Moraxella catarrhalis , and Haemophilus influenzae , without affecting, or minimally affecting, S. salivarius strains, oral probiotics commonly used to reduce oral and middle ear infection recurrence, especially in children. Our results not only demonstrated a stronger antimicrobial action of winterized LO (WLO) on S. pyogenes , compared to what was seen with LO, but also demonstrated a strong antimicrobial action vs. S. pneumoniae and M. catarrhalis and a very limited effect on S. salivarius (strains K12 and M18). Moreover, WLO demonstrated a co-acting action when tested along with the antibiotics amoxicillin (A) and amoxicillin clavulanate (AC), effects clearly visible also on H. influenzae. Our results also showed that at least part of the antimicrobial effect observed was due to the presence of anacardic acids (AAs). Finally, WLO, when tested with human peripheral blood mononuclear cells (h-PBMCs), reduced the release of IL-6 and TNF-α and, in the case of cells stimulated by LPS, the release of IFN-γ. In conclusion, our study highlights an enhanced antimicrobial role for LO when winterized, suggests a co-acting effect of this when given with antibiotics, identifies AAs as possible active ingredients, and proposes a possible anti-inflammatory role for it. [ABSTRACT FROM AUTHOR]

Abstract Objectives The aim of this study was to determine the asymptomatic pharyngeal carriage rate of S. pyogenes, antimicrobial pattern and related risk factors among school children in Hawassa, southern Ethiopia. Results Out of 287 school children’s screened, 35 (12.2%) were colonized with S. pyogenes. The carriage rate was significantly associated with factors such as sex (female p = 0.013) occupational status of mother (p = 0.002), lower income source (500–900 ETB, 1000–1500 ETB) (p = 0.001, and p = 0.042), history of hospitalization (p = 0.00) and residence of the children (p = 0.002). High level resistant to tetracycline and low level to vancomycin were observed, while penicillin, amoxicillin, erythromycin, chloramphenicol, and ceftriaxone were found to be effective.

Abstract Background Group A Streptococcal (GAS) infections cause the autoimmune disease acute rheumatic fever (ARF), which can progress to chronic rheumatic heart disease (RHD). Treating pharyngitis caused by GAS with antibiotics is important in preventing ARF. However, it is difficult to distinguish these infections from GAS carriers. There is growing evidence for GAS skin infections as a cause of ARF. This study will identify the incidence of true GAS pharyngitis and serological responses to GAS skin infections. The effectiveness of antibiotics for these conditions will be explored, and modifiable risk factors. Serum antibody titres indicating the upper limits of normal (ULN for ASO/ADB antibodies) will be established alongside carriage rates in asymptomatic children. Methods This is a prospective disease incidence study, with an associated case-control study. The study population includes 1000 children (5–14 years) from Auckland, New Zealand, 800 of whom have visited their healthcare professional, resulting in a throat or skin swab for GAS, and 200 who are asymptomatic. The conditions of interest are GAS throat swab positive pharyngitis (n = 200); GAS carriage (n = 200); GAS negative throat swab (n = 200); GAS skin infections (n = 200); and asymptomatic controls (n = 200). All participants, except asymptomatic controls, will have acute and convalescent serological testing for ASO/ADB titres (collected

The review is devoted to the analysis of molecular mechanisms of action of S. pyogenes virulence factors aimed at overcoming the protective functions of macrophages. The review describes in detail the main protective functions of macrophages and the mechanisms of their implementation in the course of streptococcal infection. The virulence factors of S. pyogenes, which prevent the recruitment of macrophages to the site of infection, are examined. Particular attention is paid to the analysis of molecular effects that suppress the pathogen by the process of phagocytosis, intracellular bactericidal activity and the production of cytokines by macrophages. The analysis of molecular genetic mechanisms of regulation of the expression of S. pyogenes virulence factors that provide adaptation of the pathogen to changing conditions in the site of inflammation is carried out.

Streptococcus pyogenes was the most common bacterial causes of tonsillitis. The detection of virulence factors of this pathogen can be used to determine pathogenic potential as a rapid screening method. A total of 109 isolates (46%) showed positive culture for S. pyogenes, these isolates recovered from 235 swabs were collected from tonsillitis patients in ENT department in Al–Habboby Teaching Hospital, Thi-Qar province, Iraq. S. pyogenes isolates exposed to detect the specific gene (spy1258)and one of the virulence factors were smeZ gene by PCR technique and DNA sequencing analysis. The PCR results recorded that 61% and 50% of isolates harbor spy1258 and smeZ genes, respectively. The sequencing of PCR products showed significant alignments identities (94-100%) to the S. pyogenes for both genes which are located in BLAST-NCBI Genbank. The four PCR products of both genes were registered in Genbank under the named as (ZKD1 Spy-like gene; ZKD2 Spy-like gene; ZKD3 SmeZ-like gene and ZKD4 SmeZ-like gene). The results of Multiple sequence alignment analysis recorded that C > T and T > C polymorphism for smeZ gene.

Streptococcus pyogenes infections continue to be a worldwide public health problem, causing various diseases in humans, with rheumatic fever and rheumatic heart disease being the most harmful manifestations. Impetigo and post-streptococcal glomerulonephritis are also important sequelae of skin infections. We have developed a candidate vaccine epitope (StreptInCor) that presents promising results in diverse animal models. To assess whether the StreptInCor alum-adsorbed vaccine could induce undesirable effects, a certified independent company conducted a repeated intramuscular dose toxicity evaluation in Wistar rats, a choice model for toxicity studies. We did not observe significant alterations in clinical, hematological, biochemical, anatomical, or histopathological parameters due to vaccine administration, even when the animals received the highest dose. In conclusion, repeated intramuscular doses did not show signs of macroscopic or other significant changes in the clinical or histopathological parameters, indicating that StreptInCor can be considered a safe candidate vaccine.

Background: Streptococcus pyogenes (S. pyogenes) is a Gram positive bacterium which is a leading cause of pharyngitis, skin and soft tissue infection and post streptococcal syndromes. Due to lack of β-lactamase enzyme production, it was considered universally susceptible to penicillin group and later generation of β-lactam antibiotics. As such, empirical treatment was common which might leads to development of antibiotics resistance. Therefore, the aims of this study were to determine the prevalence, antibiotics susceptibility profile; and associated factors of S. pyogenes among pediatric patients with acute pharyngitis in Felege Hiwot Comprehensive Specialized Hospital (FHCSH), Northwest Ethiopia. Methods: Hospital based cross-sectional study was carried out on 154 pediatric patients, whose age ranged from 0 to 18 years old using consecutive convenient sampling technique from 1st February to 19th June 2020 at FHCSH. S. pyogenes were identified by throat swab culture on 5% sheep blood agar with an overnight incubation at 37 °C in candle jar containing 5% CO2. Gram stain, catalase test and bacitracin test were used to identify S. pyogenes. Then,the data were entered into EpiData version 3.1 and analyzed by SPSS version 20 software. Finally, stepwise, bivariable and multivariable logistic regressions were carried out for identifyying factors having significant ssociation (p<0.05) with acute pharyngitis. Results: From the total throat swabs, 14 (9.1%) with (95% CI; 4.5–14.3) were culture positive for S. pyogenes. From these, all isolates were sensitive to penicillin and ampicillin. On the otherhand, 4 (35.7%), 4 (35.5%), 3 (21.4%), 2 (14.3%), 1 (7.1%), 7 (50.0%) and 1 (7.1%) isolates were resistant for ceftriaxone, vancomycin, erythromycin, tetracycline, chloramphenicol, clindamycin and levofloxacin, respectively. The presence of any smoker in home showed significant association with S. pyogenes acute pharyngitis. Furthermore, having tender lymphadenopathy and recurrence were clinical predictors for S. pyogenes acute pharyngitis (P < 0.05). Conclusion: The prevalence of S. pyogenes was guaged at 9.1% which is considered as low prevalence. All S. pyogenes isolats remain sensitive to penicillin. However, resistance was reported to clindamycin 7 (50.0%), ceftriaxone 5 (35.7%) and erythromycin 3 (21.4%). The current practice of giving erythromycin, clindamycin instead of penicillin and ampicillin is againest the microbiology result. Therefore, current empirical treatment of acute pharyngitis shall take in to account the current evidences. Continuous surveillance of antibiotics resistance pattern of S. pyogenes for acute pharyngitis must be strengthen to improve the use of antibiotics in hospitals. [ABSTRACT FROM AUTHOR]

Objectives: Streptococcus pyogenes (group A Streptococcus [GAS]) is a prevalent cause of community-acquired bacterial infections, with invasive GAS (iGAS) infections presenting severe morbimortality. Clindamycin is generally used based on its antitoxin effect. This study investigates changes in iGAS incidence, clinical presentation, outcomes, and clindamycin resistance in an adult cohort., Methods: This is a retrospective analysis of S. pyogenes episodes from a tertiary adult hospital in Barcelona (Spain) between 2015 and 2023. The pre-pandemic period includes data from 2015-2019. The pandemic period, from 2020-2021, and post-pandemic period comprised 2022 to the first semester of 2023., Results: The global incidence of GAS infections in the pre-pandemic and post-pandemic periods were 2.62 and 2.92 cases per 10.000 hospital admissions, whereas for iGAS cases, they were 1.85 and 2.34. However, a transient decrease was observed during the pandemic period: 1.07 and 0.78 per 10.000 hospital admissions. There was a significant decrease in GAS and iGAS infections during the pandemic period compared with the pre-pandemic incidence ( P <0.001 for GAS infections and P = 0.001 for iGAS cases) and the post-pandemic incidence ( P = 0.032 for GAS infections and P = 0.037 for iGAS cases). The most common source of infection was skin and soft tissue infections with 264 (54%) cases. Skin and soft tissue infections and cases of necrotizing fasciitis increased during the pandemic. Clindamycin resistance occurred in 13.5% of isolations during the pre-pandemic and 17.5% in post-pandemic period ( P = 0.05)., Conclusions: Our study revealed a temporary reduction in iGAS infections, followed by resurgence in the post-pandemic period. The observed rise in clindamycin resistance emphasizes the importance of monitoring local resistance patterns for tailored treatment., Competing Interests: On behalf of all authors, the corresponding author states that there is no conflict of interest. No funding or financial support was received for the production of the present work., (© 2024 The Author(s).)

The protective role of macrophages closely related to the production of bactericidal molecules, in which nitrogen monoxide (NO) play an important role. Arginine serves as a substrate for inducible NO synthase (iNOS) in course of NO production. Expression and activity of iNOS are regulated by the availability of the substrate (arginine) in the intercellular space. The bacterial enzyme arginine deiminase also uses arginine as a substrate, causing its deficiency for host cells. The aim of this study was to confirm the possible role of arginine deiminase from S. pyogenes in inhibiting NO synthesis by macrophages. For this purpose, a comparative study was made of the effect on the synthesis of NO by macrophages of the products of destruction of two strains: the initial S. pyogenes M49-16 and the isogenic mutant S. pyogenes M49-16 delArcA with the inactivated arginine deiminase gene (arcA). It has been shown that the ability of S. pyogenes M49-16 to inhibit production of NO by macrophages depends on its arginine deiminase activity because the isogenous mutant of S. pyogenes M49-16 delArcA with the inactivated gene arcA has lost its ability to inhibit NO synthesis. This allows us to consider the effects of S. pyogenes M49-16 as effects of arginine deiminase. An analysis of the inhibitory mechanisms of the enzyme showed that suppression of NO synthesis was not associated with the effect of destruction products of S. pyogenes M49-16 on the viability of macrophages. According to data of flow cytometry, incubation of cells in the presence of S. pyogenes destruction products of the original and mutant strains did not affect the level of iNOS expression, i.e. did not alter synthesis or stability of this enzyme. At the same time, the decrease in NO production under the influence of the original S. pyogenes strain M49-16 correlated with a decrease in the content of arginine in the culture medium. When exogenous arginine to the culture medium was added, the effect of the original strain of the suppression of NO production was declined. This confirms that the depletion of arginine is the main mechanism of the inhibitory effect of arginine deiminase on the production of NO by macrophages. The deficiency of NO production in the course of streptococcal infection can lead to a weakening of bactericidal activity of macrophages and to a decrease in the effectiveness of antimicrobial protection.

Streptococcal infection is characterized by a variety of manifestations from asymptomatic carriage of the pathogen to manifest forms. Recently, in addition to the bacteriological method for confirming streptococcal etiology, the rapid test for β-hemolytic streptococcus group A is increasingly being used. Isolation of streptococci does not always indicate their involvement in pathology, quite often a person is a healthy carrier of the pathogen. The share of carrier is 10—28% of cases. However, in the practical activities of a physician, positive tests for β -hemolytic streptococcus group A (rapid test or bacteriological culture) are often treated as acute streptococcal infection even in children without any clinical manifestations of acute tonsillopharyngitis and, as a result, antibiotic therapy is prescribed.For differential diagnosis, a correct evaluation of epidemiological and clinical data with a mandatory serological test — the determination of ASO in paired sera with an interval of 7—10 days is required. Absence of an increase in antibodies indicates carrier.b-hemolytic streptococcus group A carriers in most cases do not need antibiotic therapy. However, if there is a history or risk of developing rheumatic fever, acute poststreptococcal glomerulonephritis, antibiotic therapy is necessary.The authors proposed an algorithm for managing patients with the release of b-hemolytic streptococcus group A from the oropharynx.

Copyright of Jornal de Pediatria is the property of Sociedade Brasileira de Pediatria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aimed to investigate the antibacterial and antibiofilm activities of Trigona honey against Pseudomonas aeruginosa and Streptococcus pyogenes. The antimicrobial and anti-biofilm activities were examined by agar well diffusion assays, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill curve, biofilm formation in 96-well plates and scanning electron microscope (SEM). Larger zones of inhibition were recorded from the agar well diffusion method. Trigona honey samples showed clear zones of inhibitions against P. aeruginosa and S. pyogenes, 25.2±0.6mm and 26.7±1.0mm respectively. Trigona honey possessed the lowest MIC value against P. aeruginosa and S. pyogenes was 20% (w/v) and MBC was 25% (w/v). In addition, MICR50R was between 10%-12.5% (w/v) and MICR90R was between 20%-25% (w/v) concentration of honey for both bacteria. In time-kill curve, Trigona honey inhibited P. aeruginosa and S. pyogenes in a 3 logR10R at 18 hours, and total viable counts (TVCs) were killed after 24 hours at honey concentration of 25%. In biofilm degradation assay, Trigona honey degraded 70% of P. aeruginosa and 68% of S. pyogenes biofilm. Also in biofilm inhibition assay, Trigona honey inhibited 91% of P. aeruginosa and 89% of Streptococcus pyogenes biofilms. SEM images of P. aeruginosa and S. pyogenes showed that Trigona honey changed shape, size of cells, destroyed cell wall integrity and lysed the cells in both bacteria. Scanning electron microscope images for biofilm of P. aeruginosa and S. pyogenes showed that Trigona honey decreased cell density, and cells appeared curved of P. aeruginosa and rough, holes and crevices of S. pyogenes. In sum, Trigona honey disrupted and damaged biofilm formation. This study demonstrated that Trigona honey has high antibacterial and antibiofilm activities against both bacteria in vitro and showed the efficacy of honey against biofilm in different degrees of potential effect. The study supports previous finding that Trigona honey can be used as an alternative medicine for various bacterial infections. [ABSTRACT FROM AUTHOR]

Copyright of Iraq Journal of Market Research & Consumer Protection / Al-Mağallaẗ al-ʿIrāqiyyaẗ li-Buḥūṯ al-Sūq wa-Ḥimāyaẗ al-Mustahlik is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Staphylococcus aureus and Streptococcus pyogenes are the causative agents of cellulitis, a bacterial skin infection. Cellulitis primarily affects the skin, and it later spreads to the other parts of the body, especially through the lymph nodes and bloodstream. Without proper medication, it becomes life-threatening. The main symptoms include inflammation, tenderness, tight and swollen skin, and fever. Vaccines using epitopes as antigens trigger quick immune responses; in addition, they are cost effective. These antigens are derived from bacterial proteins. In this study, virulence factors from membrane proteins such as sak, tst, isdA, clfB, and can from S. aureus (Fig. 1) and SPy, scpA, and hylp1 from S. p yogenes (Fig. 2) were selected for predicting the vaccine epitopes. VaxiJen server was used to evaluate the antigenicity of the selected proteins; BCPred, AAPPred, and ABCpred were used for B-cell epitope prediction, while ProPred and ProPred I were used for T-cell epitope prediction. MHCPred was used for the selected alleles, DRB1*0101 and DRB1*0401. Pepitope server was used for epitope mapping of the selected peptides. Epitopes that are common among those from BCPred, AAPPred, and ABCpred were selected: LKYGPKFDK (tst) and MTFDDKNGK (cna) from S. aureus and YTNSDKGGS (SPy), FKIEPDTTV (SPy), MTPSERLDL (scpA), VKTDDQQDK (scpA), and LKFKPAATV (hylp1) from S. pyogenes. Among them, YTNSDKGGS, MTPSERLDL, and MTFDDKNGK, were identified as suitable vaccine candidates for eliciting immune responses. These results of this study can be used to create a peptide-based vaccine for preventing cellulitis. [ABSTRACT FROM AUTHOR]

There is a growing body of data about the cytopathic effect of bacterial arginine deiminase on human endothelial cells, but the precise mechanisms of endothelial dysfunction caused by the activity of the enzyme remain poorly understood. Activity of arginine deiminase causes arginine depletion in the microenvironment of the host organism cells. In view that arginylation of beta-actin regulates actin cytoskeleton structure and cell motility, we proposed that the cytopathic effect of arginine deiminase may be associated with disruption of actin in the cytoskeleton of endothelial cells. The aim of this study was to investigate the effect of arginine deiminase from S. pyogenes on migration and actin cytoskeleton structure of the human endothelial cells, line EA.hy926. The supernatant of sonicated S. pyogenes M49-16, its isogenic mutant with a deletion of the arginine deiminase gene (S. pyogenes M49-16delAD), supernatant of sonicated S. pyogenes M22, and arginine deiminase isolated from the latter strain were used. The effect of bacterial factors on migration activity of endothelial cells was studied in the model of "wound healing" in vitro. To analyze the influence of bacterial factors on the actin cytoskeleton structure, cells were stained with phalloidin-rhodamine. It was shown that supernatants of destroyed S. pyogenes, as well as arginine deiminase significantly reduced the migration activity of endothelial cells and altered the structure of their actin cytoskeleton. The supernatants of destroyed S. pyogenes M49-16delAD with deleted gene of arginine deiminase showed a significantly reduced ability to suppress cell migration as compared with the supernatant of sonicated S. pyogenes M49-16. No significant differences were revealed in the structure of actin filaments in cells cultured in the presence of supernatants of destroyed S. pyogenes M19-16, and cells cultured in the presence of isogenic mutant S. pyogenes M4916delAD. Adding exogenous arginine to the cells cultured with supernatants of destroyed S. pyogenes did not restore their migratory activity and the structure of their actin cytoskeleton. However, if arginine deficiency caused by the activity of arginine deiminase was compensated, endothelial cells migration activity was restored, and the structure of actin cytoskeleton was recovered. A decrease of migration activity of endothelial cells under the influence of streptococcal arginine deiminase was due to the disruption of actin cytoskeleton structure.

Arginine deiminase is a bacterial enzyme that hydrolyses arginine with citrulline and ammonia formation. In recent years, increasing evidence is reported about in vitro and in vivo anti-angiogenic action of arginine deiminase from Mycoplasma spp. Our studies have shown that arginine deiminase from Streptococcus pyogenes M22 exerts similar effects, i.e., inhibits proliferation and other endothelial cell functions related to angiogenesis. To confirm a leading role of arginine deiminase, as a factor responsible for the anti-proliferative effect, we have constructed an isogenic S. pyogenes M49-16 mutant unable to express arginine deiminase. A comparative analysis of anti-proliferative activity of original S. pyogenes M49-16 strain and its isogenic mutant with arginine deiminase gene deletion (M49-16delAD) was performed, using an endothelial EA.hy926 cell line. The bacterial supernatantes obtained by sonication of S. pyogenes M49-16 and M49-16delAD were tested. The ability of S. pyogenes M49-16 and M49-16delAD supernatantes to hydrolyze arginine was assessed. Moreover, we compared effects of the Streptococcus supernatantes upon proliferative activity of endothelial cells and their distribution through the cell cycle phases.Supernatantes from original S. pyogenes 49-16 strain were shown to inhibit endothelial cell proliferation to a significant degree (down to 50% of controls). This effect was due to its arginine hydrolyzing activity, i. e. addition of exogenous arginine to the medium resulted into recovery of the cell proliferation levels. The supernatante from S. pyogenes M49-16delAD showed a lower ability to hydrolyze arginine as compared to the supernatante of original strain. Culturing of endothelial cells supplied with S. pyogenes M49-16delAD supernatantes resulted into reduction of their proliferative activity by 10% of control values. Analysis of the cell cycle distribution was concordant with these results. S. pyogenes M49-16 supernatante caused a decrease in S-phase cell fraction by 20% against controls. With a supernatants from S. pyogenes M49-16delAD, such drop in DNA-synthesizing cell ratio was significantly weaker (by only 5% of the control). These results reveal new pathogenetic mechanisms of endothelial dysfunction during streptococcal infection and suggest anti-angiogenic potential of streptococcal arginine deiminase.

Streptococcus pyogenes was the most common bacterial causes of tonsillitis. The detection of virulence factors of this pathogen can be used to determine pathogenic potential as a rapid screening method. A total of 109 isolates (46%) showed positive culture for S. pyogenes, these isolates recovered from 235 swabs were collected from tonsillitis patients in ENT department in Al–Habboby Teaching Hospital, Thi-Qar province, Iraq. S. pyogenes isolates exposed to detect the specific gene (spy1258)and one of the virulence factors were smeZ gene by PCR technique and DNA sequencing analysis. The PCR results recorded that 61% and 50% of isolates harbor spy1258 and smeZ genes, respectively. The sequencing of PCR products showed significant alignments identities (94-100%) to the S. pyogenes for both genes which are located in BLAST-NCBI Genbank. The four PCR products of both genes were registered in Genbank under the named as (ZKD1 Spy-like gene; ZKD2 Spy-like gene; ZKD3 SmeZ-like gene and ZKD4 SmeZ-like gene). The results of Multiple sequence alignment analysis recorded that C > T and T > C polymorphism for smeZ gene. [ABSTRACT FROM AUTHOR]

Aim. Study the effect of components of destroyed streptococci on human blood monocyte functions related to processes of trans-endothelial migration in vitro. Materials and methods. Mononuclear leukocytes, isolated from blood of healthy donors, endothelial cells of EA.hy 926 line and supernatant of ultrasound disintegrated Streptococcus pyogenes (DSS) were the objects of the study. Evaluation of adhesion and monocyte migration, level of expression of adhesion molecules and phosphokinases on monocytes was carried out by flow cytometry using monoclonal antibodies. Cytokine concentration was determined by using standard commercial test systems in enzyme immunoassay. Results. Under the effect of DSS, expression of adhesion molecules CD162 and CD11b, as well as phospho-p38 MAPK changed, IL-6 and IL-8 secretion induction took place. DSS caused enhancement of migration and adhesive activity of monocytes, however, inhibited intensity of trans-endothelial migration. Conclusion. Products of destroyed streptococci have a multi-directional effect on human blood monocytes, that could be explained by the presence of components with varying biological activity in DSS.

Bacterial SOS response is an inducible system of DNA repair and mutagenesis. Streptococci lack a canonical SOS response, but an SOS-like response was reported in some species. The mef (A)- msr (D)-carrying prophage Ф1207.3 of Streptococcus pyogenes contains a region, spanning orf6 to orf11 , showing homology to characterized streptococcal SOS-like cassettes. Genome-wide homology search showed the presence of the whole Φ1207.3 SOS-like cassette in three S . pyogenes prophages, while parts of it were found in other bacterial species. To investigate whether this cassette confers an SOS-mutagenesis phenotype, we constructed Streptococcus pneumoniae R6 isogenic derivative strains: (i) FR172, streptomycin resistant, (ii) FR173, carrying Φ1207.3, and (iii) FR174, carrying a recombinant Φ1207.3, where the SOS-like cassette was deleted. These strains were used in survival and mutation rate assays using a UV-C LED instrument, for which we designed and 3D-printed a customized equipment, constituted of an instrument support and swappable-autoclavable mini-plates and lids. Upon exposure to UV fluences ranging from 0 to 6,400 J/m 2 at four different wavelengths, 255, 265, 275, and 285 nm, we found that the presence of Φ1207.3 SOS-like cassette increases bacterial survival up to 34-fold. Mutation rate was determined by measuring rifampicin resistance acquisition upon exposure to UV fluence of 50 J/m 2 at the four wavelengths by fluctuation test. The presence of Φ1207.3 SOS-like cassette resulted in a significant increase in the mutation rate (up to 18-fold) at every wavelength. In conclusion, we demonstrated that Φ1207.3 carries a functional SOS-like cassette responsible for an increased survival and increased mutation rate in S. pneumoniae . IMPORTANCE Bacterial mutation rate is generally low, but stress conditions and DNA damage can induce stress response systems, which allow for improved survival and continuous replication. The SOS response is a DNA repair mechanism activated by some bacteria in response to stressful conditions, which leads to a temporary hypermutable phenotype and is usually absent in streptococcal genomes. Here, using a reproducible and controlled UV irradiation system, we demonstrated that the SOS-like gene cassette of prophage Φ1207.3 is functional, responsible for a temporary hypermutable phenotype, and enhances bacterial survival to UV irradiation. Prophage Φ1207.3 also carries erythromycin resistance genes and can lysogenize different pathogenic bacteria, constituting an example of a mobile genetic element which can confer multiple phenotypes to its host., Competing Interests: The authors declare no conflict of interest.

The Streptococcus pyogenes phospholipase A2 (SlaA) gene is highly conserved in the M3 serotype of group A S. pyogenes, which often involves hypervirulent clones. However, the role of SlaA in S. pyogenes pathogenesis is unclear. Herein, we report that SlaA induces the expression of intercellular adhesion molecule 1 (ICAM1) and vascular cell adhesion molecule 1 (VCAM1) via the arachidonic acid signaling cascade. Notably, recombinant SlaA induced ICAM1 and VCAM1 expression in human umbilical vein endothelial cells (HUVECs), resulting in enhanced adhesion of human monocytic leukemia (THP-1) cells. However, C134A, a variant enzyme with no enzymatic activity, did not induce such events. In addition, culture supernatants from S. pyogenes SSI-1 enhanced the adhesion of THP-1 cells to HUVECs, but culture supernatants from the ΔslaA isogenic mutant strain had limited effects. Aspirin, a cyclooxygenase 2 inhibitor, prevented the adhesion of THP-1 cells to HUVECs and did not induce ICAM1 and VCAM1 expression in HUVECs treated with SlaA. However, zileuton, a 5-lipoxygenase inhibitor, did not exhibit such effects. Furthermore, pre-administration of aspirin in mice intravenously injected with SlaA attenuated the transcriptional abundance of ICAM1 and VCAM1 in the aorta. These results suggested that SlaA from S. pyogenes stimulates the expression of adhesion molecules in vascular endothelial cells. Thus, SlaA contributes to the inflammation of vascular endothelial cells upon S. pyogenes infection.

Gene specific DNA based sensors have potential applications for rapid and real time monitoring of hybridization signal with the target nucleic acid of pathogens. Different types of DNA based sensors and their applications have been studied for rapid and accurate detection of pathogens causing human diseases. These sensors are based on surface plasmon resonance, quantum-dots, molecular beacons, piezoelectric and electrochemical etc. Curbing epidemics at an early stage is one of the massive challenges in healthcare systems. Timely detection of the causative organism may provide a solution to restrain mortality caused by the disease. With the advent of interdisciplinary sciences, bioelectronics has emerged as an effective alternative for disease diagnostics. Gene specific DNA sensors present themselves as cost-effective, sensitive and specific platforms for detection of disease causing pathogens. The mini review explores different transducer based sensors and their potential in diagnosis of acute and chronic diseases. [ABSTRACT FROM AUTHOR]

An impedimetric mga gene specific DNA sensor was developed by immobilization of single stranded DNA probe onto the screen printed modified gold-dendrimer nanohybrid composite electrode for early and rapid detection of S. pyogenes in human throat swab samples causing rheumatic heart disease. Electrochemical impedance response was measured after hybridization with bacterial single stranded genomic DNA (ssG-DNA) with probe. The sensor was found highly specific to S. pyogenes and can detect as low as 0.01 ng ssDNA in 6 µL sample only in 30 min. The nanohybrid sensor was also tested with non-specific pathogens and characterized by FTIR. An early detection of the pathogen S. pyogenes in human can save damage of mitral and aortic heart valves (rheumatic heart disease) by proper medical care. [ABSTRACT FROM AUTHOR]

Streptococcus dysgalactiae subsp. equisimilis (groups C and G streptococci [GCS/GGS]) is an increasingly recognized human pathogen, although it may follow indirect pathways. Prospective surveillance of selected households in 3 remote Aboriginal communities in Australia provided 337 GCS/GGS isolates that were emm sequence-typed. Lancefield group C isolates (GCS) were localized to specific households and group G isolates (GGS) were more evenly distributed. GCS/GGS was more frequently recovered from the throat than group A streptococci (GAS [S. pyogenes]) but rarely recovered from skin sores, and then only with Staphylococcus aureus or GAS. Symptomatic GGS/GGC pharyngitis was also rare. Specific emm sequence types of GCS/GGS did not appear to cycle through the communities (sequential strain replacement) in a manner suggesting acquisition of type-specific immunity. These communities already have high levels of streptococcal and poststreptococcal disease. GCS/GGS may increase in importance as it acquires key virulence factors from GAS by lateral gene transfer.

Streptococcus pyogenes (group A streptococci, GAS) is an exclusive human bacterial pathogen. The virulence potential of this species is tremendous. Interactions with humans range from asymptomatic carriage over mild and superficial infections of skin and mucosal membranes up to systemic purulent toxic-invasive disease manifestations. Particularly the latter are a severe threat for predisposed patients and lead to significant death tolls worldwide. This places GAS among the most important Gram-positive bacterial pathogens. Many recent reviews have highlighted the GAS repertoire of virulence factors, regulators and regulatory circuits/networks that enable GAS to colonize the host and to deal with all levels of the host immune defense. This covers in vitro and in vivo studies, including animal infection studies based on mice and more relevant, macaque monkeys. It is now appreciated that GAS, like many other bacterial species, do not necessarily exclusively live in a planktonic lifestyle. GAS is capable of microcolony and biofilm formation on host cells and tissues. We are now beginning to understand that this feature significantly contributes to GAS pathogenesis. In this review we will discuss the current knowledge on GAS biofilm formation, the biofilm-phenotype associated virulence factors, regulatory aspects of biofilm formation, the clinical relevance, and finally contemporary treatment regimens and future treatment options.