Prevalence of β-hemolytic groups C and F streptococci in patients with acute pharyngitis

Co-culturing with Streptococcus anginosus alters Staphylococcus aureus transcriptome when exposed to tonsillar cells

Introduction

Improved understanding of Staphylococcus aureus throat colonization in the presence of other co-existing microbes is important for mapping S. aureus adaptation to the human throat, and recurrence of infection. Here, we explore the responses triggered by the encounter between two common throat bacteria, S. aureus and Streptococcus anginosus, to identify genes in S. aureus that are important for colonization in the presence of human tonsillar epithelial cells and S. anginosus, and further compare this transcriptome with the genes expressed in S. aureus as only bacterium.

Methods

We performed an in vitro co-culture experiment followed by RNA sequencing to identify interaction-induced transcriptional alterations and differentially expressed genes (DEGs), followed by gene enrichment analysis.

Results and discussion

A total of 332 and 279 significantly differentially expressed genes with p-value < 0.05 and log2 FoldChange (log2FC) ≥ |2| were identified in S. aureus after 1 h and 3 h co-culturing, respectively. Alterations in expression of various S. aureus survival factors were observed when co-cultured with S. anginosus and tonsillar cells. The serine-aspartate repeat-containing protein D (sdrD) involved in adhesion, was for example highly upregulated in S. aureus during co-culturing with S. anginosus compared to S. aureus grown in the absence of S. anginosus, especially at 3 h. Several virulence genes encoding secreted proteins were also highly upregulated only when S. aureus was co-cultured with S. anginosus and tonsillar cells, and iron does not appear to be a limiting factor in this environment. These findings may be useful for the development of interventions against S. aureus throat colonization and could be further investigated to decipher the roles of the identified genes in the host immune response in context of a throat commensal landscape.

Shotgun whole genome sequencing of drug-resistance Streptococcus anginosus strain 47S1 isolated from a patient with pharyngitis in Saudi Arabia

BACKGROUND

Streptococcus anginosus is an emergence opportunistic pathogen that colonize the human upper respiratory tract (URT), S. anginosus alongside with S. intermedius and S. constellatus, members of S. anginosus group, are implicated in several human infections. However, our understanding this bacterium to the genotype level with determining the genes associated with pathogenicity and antimicrobial resistance (AMR) is scarce. S. anginosus 47S1 strain was isolated from sore throat infection, the whole genome was characterized and the virulence & AMR genes contributing in pathogenicity were investigated.

METHODOLOGY

The whole genome of 47S1 was sequenced by Illumina sequencing technology. Strain 47S1 genome was de novo assembled with different strategies and annotated via PGAP, PROKKA and RAST pipelines. Identifying the CRISPR-Cass system and prophages sequences was performed using CRISPRloci and PhiSpy tools respectively. Prediction the virulence genes were performed with the VFDB database. AMR genes were detected in silico using NCBI AMRFinderPlus pipeline and CARD database and compared with in vitro AST findings.

RESULTS

β-hemolytic strain 47S1 was identified with conventional microbiology techniques and confirmed by the sequences of 16S rRNA gene. Genome of 47S1 comprised of 1981512 bp. Type I-C CRISPR-Cas system and 4 prophages were detected among the genome of 47S1. Several virulence genes were predicted, most of these genes are found in other pathogenic streptococci, mainly lmb, pavA, htrA/degP, eno, sagA, psaA and cpsI which play a significant role in colonizing, invading host tissues and evade form immune system. In silico AMR findings showed that 47S1 gnome harbors (tetA, tetB &tet32), (aac(6')-I, aadK &aph(3')-IVa), fusC, and PmrA genes that mediated-resistance to tetracyclines, aminoglycosides, fusidic acid, and fluoroquinolone respectively which corresponds with in vitro AST obtained results. In conclusion, WGS is a key approach to predict the virulence and AMR genes, results obtained in this study may contribute for a better understanding of the opportunistic S. anginosus pathogenicity.

Fulminating deep tissue space infection with Streptococcus constellatus presenting initially as a sore throat

Management of sore throat requires robust decision-making to balance successfully the conflicting risks of unnecessary antibiotic use against those of untreated bacterial infection. We present a case of fulminant sepsis caused by Streptococcus constellatus, presenting as a sore throat, initially managed conservatively. Despite subsequent appropriate anti-microbial therapy and surgical drainage, contiguous spread ultimately involved the deep neck spaces, mediastinum and thoracic wall, and was complicated by severe aspiration pneumonia, pharyngocutaneous and bronchopleural fistulation. The complexity and widespread extent of the infected spaces, in conjunction with the catabolic response to sepsis, created a life-threatening situation. Surgical closure of the pharyngeal defect, using a pectoralis-major pedicle flap, was successfully undertaken to ensure source control of the infection and heralded a complete recovery. We describe our management of this case, discuss the current approach to the management of patients presenting with a sore throat, and review the literature on S. constellatus infections.

Beta-Hemolytic Nongroup A Streptococcal Pharyngitis in Children

OBJECTIVE

To evaluate the epidemiology, clinical features, and antibiotic prescribing patterns for nongroup A streptococci (NGAS) in children.

STUDY DESIGN

Throat cultures obtained for pharyngitis were assessed at a large community-based health system over 10 years. Epidemiologic and clinical features of children with NGAS were compared with children with group A Streptococcus (GAS) and negative cultures. Antibiotic prescribing patterns were evaluated.

RESULTS

A total of 224 328 rapid streptococcal antigen tests and 116 578 throat cultures were performed. Clinical analysis was completed for 602 GAS-positive patients, 535 NGAS-positive patients, and 480 patients with negative cultures. Incidence of NGAS did not vary annually or by season but increased with age from 2% at ≤5 years to 7% at 18 years of age. Patients with NGAS were more likely than those with negative cultures to have tonsillar exudate (20.3% vs 13.1%, P = .003) and enlarged tonsils (28.6% vs 19.3%, P < .001). Modified Centor scores did not differ between groups (score ≥2, P = 1.0; score ≥3, P = .50). Patients with GAS were more likely than those with NGAS to have fever (32.6% vs 24.5%, P = .003), palatal petechiae (14.0% vs 3.1%, P < .001), and modified Centor score ≥2 (47.8% vs 27.1%; P < .001). Of patients with NGAS, 65% were prescribed antibiotics.

CONCLUSIONS

NGAS likely exist in both carriage and infectious states and incidence increases with age. Infections associated with NGAS are milder than with GAS, and complications are rare. Laboratory reporting of NGAS results in high antibiotic use, despite current recommendations against treatment.

Castanopsis lamontii Water Extract Shows Potential in Suppressing Pathogens, Lipopolysaccharide-Induced Inflammation and Oxidative Stress-Induced Cell Injury

Castanopsis lamontii is traditionally used to prevent inflammatory diseases such as periodontitis and pharyngitis by residents in southwest China. However, little scientific evidence has been found to support this. In this research, the antibacterial activities of Castanopsis lamontii water extract (CLE) were assessed using the micro-dilution method. The anti-inflammatory and antioxidant activities of CLE were investigated in RAW264.7 cells. Key bioactive compounds in CLE were also explored. Results showed that CLE was capable of inhibiting the periodontitis pathogen Porphyromonas gingivalis and the pharyngitis pathogen β-hemolytic Streptococcus. It suppressed lipopolysaccharide-induced inflammation in RAW 264.7 cells via inactivating the TLR4/NF-κB pathway. Besides, it reduced oxidative stress-induced cell injury via scavenging reactive oxygen species. Chemical composition analysis revealed that CLE was rich in epicatechin and procyanidin B2. Further studies confirmed that epicatechin predominantly contributed to the antibacterial activities of CLE, while procyanidin B2 was mainly responsible for the anti-inflammatory activities of CLE. Both compounds contributed to the antioxidant activities of CLE. Acute oral toxicity tests proved that CLE was practically non-toxic. These results provide experimental evidences of the health-beneficial effects of CLE and may help promote the application of CLE in the food and health industries.

Prevalence of Beta-Hemolytic Streptococci Groups A, C, and G in Patients with Acute Pharyngitis

Context:

Group A beta-hemolytic streptococci (GAS) is the most frequently isolated pathogen in acute pharyngitis. However, the role of Group C (GCS) and Group G (GGS) streptococci in disease burden is under recognized. The present study is carried out to find out the prevalence of acute pharyngitis caused by the different serogroups of streptococci and antibiotic susceptibility pattern of these streptococcal isolates.

Study and Design:

A cross sectional study.

Materials and Methods:

A total of 218 throat swabs from patients with acute pharyngitis and 82 from healthy controls were collected and processed as per standard protocol. Samples were inoculated on blood agar and Streptococcus selective agar. Isolates were identified by the conventional method and serogrouped by latex agglutination test using Remel Streptex kit.

Results:

Beta-hemolytic streptococci (BHS) were isolated from 34 (15.59%) of pharyngitis patients and 11 (13.41%) of the healthy carrier. Among pharyngitis, GAS was isolated from 20 (9.17%), GCS 7 (3.21%), and GGS 7 (3.21%) patients. Carriage rate of GAS was 6 (7.31%) and GCS, 5 (6.09%). Vancomycin (100%), amoxyclavulanic acid (90%), levofloxacin (85%), and cephotaxime (80%) were found to be most effective antibiotics. Comparatively, higher drug resistance was observed among GCS and GGS to all the drugs used in the study except for levofloxacin.

Conclusions:

Although rate of pharyngitis associated with GCS and GGS is marginally lower than GAS, their carriage rate among healthy and relative higher drug resistance emphasizes the need for periodic surveillance of infection by the different serogroups of BHS.

Evaluation of cytokines produced by β-hemolytic streptococcus in acute pharyngotonsillitis

INTRODUCTION

The most common pathogen in bacteria lpharyngotonsillitis is group A β-hemolytic streptococcus, although groups B, C, F,and G have also been associated with pharyngotonsillitis.

OBJECTIVE

To assess the levels of the cytokines TNF-α, IL-6,IL-4, and IL-10 in bacterial pharyngotonsillitis caused by group A and non-A (groups B, C, F and G) β-hemolytic streptococcus.

METHODS

The study was conducted at a pediatric emergency care unit. The sample comprised children (5-9 years old) with acute bacterial pharyngotonsillitis diagnosed between December of 2011 and May of 2012. The research involved collection of blood samples from the patients, enzyme-linked immunosorbent assay detection of TNF-α, IL-6,IL-4, and IL-10, and collection of two oropharyngeal swabs for bacterial isolation. Additionally, the medical history of the study participants was also collected.

RESULTS

In the studied group (mean age: 5.93 years), higher pharyngotonsillitis incidence was observed in the female gender (64.76%). Higher incidence of tonsillar exudates was observed with groups A and C. No statistically significant differences in cytokine levels were observed among groups. However, the group A and the control group showed a difference in the IL-6 level (p=0.0016).

CONCLUSIONS

The Groups A and C showed higher cytokine levels than the Groups B and control, suggesting similar immunological patterns.

Primary Purulent Pericarditis with Cardiac Tamponade due to Oropharyngeal Polymicrobial Infection: A Case Report and Literature Review

Cardiac tamponade due to purulent pericarditis with a characteristic greenish fluid is rare in this antibiotic era. It is highly fatal despite early diagnosis and advanced treatment. Gram-positive cocci are the leading cause of purulent pericarditis, which usually results from a direct or hematogenous spread of organisms to the pericardium from the primary foci of infection. We describe an index case of rapidly developing pericardial tamponade caused by oropharyngeal polymicrobial infection in the absence of a primary source of infection in a 62-year-old man, who was successfully managed with emergency large-volume pericardiocentesis followed by pericardiectomy.

Ceftaroline activity tested against uncommonly isolated Gram-positive pathogens: report from the SENTRY Antimicrobial Surveillance Program (2008-2011)

Ceftaroline was tested against 1859 clinically significant Gram-positive organisms from uncommonly isolated species. The organisms (31 species/groups) were collected from 133 medical centres worldwide over a 4-year period (2008-2011). Coagulase-negative staphylococci were generally susceptible to ceftaroline, with MIC50 values (minimum inhibitory concentration required to inhibit 50% of the isolates) of 0.06-0.5mg/L. Ceftaroline was active against Micrococcus spp. [minimum inhibitory concentration required to inhibit 90% of the isolates (MIC90)=0.06 mg/L], but showed more limited potency versus some Corynebacterium spp. and Listeria monocytogenes isolates. Ceftaroline was active against all β-haemolytic streptococci and viridans group streptococcal species/groups listed, with MIC50 and MIC90 values ranging from ≤ 0.015 mg/L to 0.03 mg/L and from ≤ 0.015 mg/L to 0.5mg/L, respectively. Based on these in vitro findings, ceftaroline may have a potential role in the treatment of infections caused by these rarer species as guided by reference MIC test results.

Clinical spectrum of rheumatic Fever and rheumatic heart disease: a 10 year experience in an urban area of South India

Background:

Rheumatic fever (RF) is an important problem concerning developing countries like India. Rheumatic heart disease (RHD) is one of the most readily preventable chronic diseases.

Aim:

This study was done to find out the clinical profile, risk factors, compliance with treatment and outcome among RF/RHD cases so as to suggest better case management strategies.

Materials and Methods:

Clinical records of 51 RF and 71 RHD cases admitted in tertiary care hospitals in Mangalore between 2001 and 2010 were reviewed retrospectively.

Results:

Mean age of RF cases were 17.4 ± 12.1 years and RHD cases were 33.2 ± 18.6 years. More than half of RF and RHD cases were males. Commonest risk factors among RF cases were poor socioeconomic status (60.4%), history of upper respiratory tract infection before disease onset (58.8%) and undernutrition (35.3%). Commonest clinical manifestation among RF cases was fever 39 (76.5%) followed by polyarthritis 34 (66.7%). Commonest valvular lesions among RHD cases was mitral stenosis with mitral regurgitation found in 42.9% cases. Compliance of patients with prophylactic antibiotics was found to be 37 (30.3%). Mortality rate was significantly more among RHD cases (P = 0.0399).

Conclusions:

Improvement of socioeconomic and nutritional factors is an important task required for primary prophylaxis and of compliance for secondary prophylaxis of RF.

Community interactions of oral streptococci

It is now clear that the most common oral diseases, dental caries and periodontitis, are caused by mixed-species communities rather than by individual pathogens working in isolation. Oral streptococci are central to these disease processes since they are frequently the first microorganisms to colonize oral surfaces and they are numerically the dominant microorganisms in the human mouth. Numerous interactions between oral streptococci and other bacteria have been documented. These are thought to be critical for the development of mixed-species oral microbial communities and for the transition from oral health to disease. Recent metagenomic studies are beginning to shed light on the co-occurrence patterns of streptococci with other oral bacteria. Refinements in microscopy techniques and biofilm models are providing detailed insights into the spatial distribution of streptococci in oral biofilms. Targeted genetic manipulation is increasingly being applied for the analysis of specific genes and networks that modulate interspecies interactions. From this work, it is clear that streptococci produce a range of extracellular factors that promote their integration into mixed-species communities and enable them to form social networks with neighboring taxa. These "community integration factors" include coaggregation-mediating adhesins and receptors, small signaling molecules such as peptides or autoinducer-2, bacteriocins, by-products of metabolism including hydrogen peroxide and lactic acid, and a range of extracellular enzymes. Here, we provide an overview of various types of community interactions between oral streptococci and other microorganisms, and we consider the possibilities for the development of new technologies to interfere with these interactions to help control oral biofilms.

Daptomycin activity against uncommonly isolated streptococcal and other gram-positive species groups

A total of 1,356 clinical isolates were tested against daptomycin by broth microdilution methods. Daptomycin was active against seven groups of viridans group streptococci (MIC50 and MIC90 values ranging from ≤0.06 and ≤0.06 μg/ml [Streptococcus bovis and Streptococcus dysgalactiae] to 0.5 and 1 μg/ml [Streptococcus mitis, Streptococcus oralis, and Streptococcus parasanguinis], respectively), beta-hemolytic streptococci serogroups C, F, and G (MIC50 and MIC90, ≤0.06 to 0.25 and 0.12 to 0.25 μg/ml, respectively), Corynebacterium spp. (MIC50 and MIC90, ≤0.06 and 0.12 μg/ml, respectively), and Micrococcus spp. (MIC50 and MIC90, ≤0.06 and 0.25 μg/ml, respectively). Listeria monocytogenes exhibited higher daptomycin MICs (MIC50 and MIC90, 2 and 4 μg/ml, respectively) than other tested organisms.