Antimicrobial resistance in beta-haemolytic streptococci in India: A four-year study

Antibiotic-resistant bacteria originating from the gut may modulate the mucosal immune response during sepsis and septic shock

The enrichment and diversity of gut microbiota play an important role in sepsis, but the role of gut microbiota composition and early-life colonization in sepsis and septic shock has not yet been characterized. The impact of gut microbiota diversity on host immunological disorders and future treatments of inflammatory diseases are not yet fully elucidated. Further, the association between the microbiota and immune development in sepsis remains unknown, and the underlying mechanisms are not well understood. The altered composition of gut microbiota during sepsis is profoundly associated with a loss of commensal bacteria and an overgrowth of potentially pathogenic bacteria, especially AMR bacteria. Disruptions of gut microbiota diversity are directly associated with susceptibility to sepsis and a higher risk of adverse outcomes. Several studies have confirmed that a mutual association between gut microbiota and the host is important for the metabolism of essential nutrients for the organism, for gut development, and for the maturation and development of a fully functional immune system. Therefore, understanding the gut microbiota diversity, composition, and function during various inflammatory conditions and sepsis may provide a comprehensive knowledge of the mechanisms behind the pathogenesis of gut-derived infection in diseases and the design of new treatment options (e.g., probiotics or fecal microbiota transplantation).

Emerging evidence displays an important role of gut microbiota and their derived metabolites in modulating the host mucosal immune response and determining the susceptibility to, as well as outcomes of sepsis.

Group A Streptococcus Infections: Their Mechanisms, Epidemiology, and Current Scope of Vaccines

Group A streptococci (GAS) are gram-positive, cocci-shaped bacteria that cause a wide variety of infections and are a cause of significant health burden, particularly in lower- and middle-income nations. The GAS genome contains a number of virulence factors such as the M-protein, hyaluronic acid, C5a peptidase, etc. Despite its significant health burden across the globe, a proper vaccine against GAS infections is not yet available. Various candidates for an effective GAS vaccine are currently being researched. These are based on various parts of the streptococcal genome. These include candidates based on the N-terminal region of the M protein, the conserved C-terminal region of the M protein, and other parts of the streptococcal genome. The development of a vaccine against GAS infections is hampered by certain challenges, such as extensive genetic heterogeneity and high protein sequence variation. This review paper sheds light on the various virulence factors of GAS, their epidemiology, the different vaccine candidates currently being researched, and the challenges associated with M-protein and non-M-protein-based vaccines. This review also sheds light on the current scenario regarding the status of vaccine development against GAS-related infections.

Group A Streptococcal Bacteremia: Ten Years’ Experience from a Tertiary Care Center in South India

Background

Patients and methods

Results

Conclusion

How to cite this article

Molecular Characteristics of Streptococcus pyogenes Isolated From Chinese Children With Different Diseases

Streptococcus pyogenes is a bacterial pathogen that causes a wide spectrum of clinical diseases exclusively in humans. The distribution of emm type, antibiotic resistance and virulence gene expression for S. pyogenes varies temporally and geographically, resulting in distinct disease spectra. In this study, we analyzed antibiotic resistance and resistance gene expression patterns among S. pyogenes isolates from pediatric patients in China and investigated the relationship between virulence gene expression, emm type, and disease categories. Forty-two representative emm1.0 and emm12.0 strains (n = 20 and n = 22, respectively) isolated from patients with scarlet fever or obstructive sleep apnea-hypopnea syndrome were subjected to whole-genome sequencing and phylogenetic analysis. These strains were further analyzed for susceptibility to vancomycin. We found a high rate and degree of resistance to macrolides and tetracycline in these strains, which mainly expressed ermB and tetM. The disease category correlated with emm type but not superantigens. The distribution of vanuG and virulence genes were associated with emm type. Previously reported important prophages, such as φHKU16.vir, φHKU488.vir, Φ5005.1, Φ5005.2, and Φ5005.3 encoding streptococcal toxin, and integrative conjugative elements (ICEs) such as ICE-emm12 and ICE-HKU397 encoding macrolide and tetracycline resistance were found present amongst emm1 or emm12 clones from Shenzhen, China.

Epidemiological analysis of Group A Streptococcus infections in a hospital in Beijing, China

Our study aimed to investigate the epidemiological and molecular characteristics of isolates collected from Group A Streptococcus (GAS) infections in children in Beijing China during the year 2019. Emm typing, superantigens, and erythromycin resistance genotypes were determined by PCR. Antimicrobial susceptibility testing was performed as recommended by Clinical Laboratory Standards Institute (CLSI). A total of 271 GAS isolates were collected. Thirteen different emm types, including 31 subtypes, were identified. The most prevalent emm types were emm12 (52.77%), emm1 (36.9%), emm3.1 (2.95%), and emm75.0 (2.95%). Two variant subtypes, STC36.0 and STG840.2, were identified. There was no difference in the portion of emm12 and emm1 isolates in scarlet fever, impetigo, and psoriasis. The majority of superantigens detected were smeZ (94.46%), speC (91.14%), and ssa (74.91%), followed by speH (56.46%), speI (45.76%), speJ (36.9%), and speA (34.32%). More scarlet fever isolates harbored speA (35.6%) and speJ (38.4%), more psoriasis isolates harbored speI (57.9%), and more impetigo isolates harbored ssa (89.7%). Isolates were universally susceptible to penicillin and resistant to erythromycin (94.83%). Moreover, 89.67% erythromycin resistance isolates harbored the ermB gene. The erythromycin resistance rate of the isolates from the three diseases was different. Scarlet fever is the common streptococcal infectious disease in dermatology. Emm12 and emm1 were the most prevalent emm types. The most prevalent superantigens detected were smeZ, spec, and ssa. There is association between diversity of superantigens and disease manifestation. Hence, continuous surveillance of GAS molecular epidemiological characterizations in different diseases is needed.

Prevalence of Group A Streptococcus in Primary Care Patients and the Utility of C-Reactive Protein and Clinical Scores for Its Identification in Thailand

Pharyngitis is usually caused by a viral infection for which antibiotics are often unnecessarily prescribed, adding to the burden of antimicrobial resistance. Identifying who needs antibiotics is challenging; microbiological confirmation and clinical scores are used but have limitations. In a cross-sectional study nested within a randomized controlled trial, we estimated the prevalence and antibiotic susceptibility profiles of group A Streptococcus (GAS) in patients presenting to primary care with a sore throat and fever in northern Thailand. We then evaluated the use of C-reactive protein (CRP) and clinical scores (Centor and FeverPAIN) to identify the presence of GAS. One hundred sixty-nine patients were enrolled, of whom 35 (20.7%) had β-hemolytic Streptococci (BHS) isolated from throat swab culture, and 11 (6.5%) had GAS. All GAS isolates were sensitive to penicillin G. The median CRP of those without BHS isolation was 10 mg/L (interquartile range [IQR] ≤ 8-18), compared with 18 mg/L (IQR 9-71, P = 0.0302) for those with GAS and 14 mg/L (IQR ≤ 8-38, P = 0.0516) for those with any BHS isolated. However, there were no significant relationships between CRP > 8 mg/L (P = 0.112), Centor ≥ 3 (P = 0.212), and FeverPAIN ≥ 4 (P = 1.000), and the diagnosis of GAS compared with no BHS isolation. Identifying who requires antibiotics for pharyngitis remains challenging and necessitates further larger studies. C-reactive protein testing alone, although imperfect, can reduce prescribing compared with routine care. Targeted CRP testing through clinical scoring may be the most cost-effective approach to ruling out GAS infection.

Acute rheumatic fever diagnosis and management: Review of the global implications of the new revised diagnostic criteria with a focus on Saudi Arabia

Rheumatic fever (RF) is a common cause of acquired heart disease in children worldwide. It is a delayed, nonsuppurative, autoimmune phenomenon following pharyngitis, impetigo, or scarlet fever caused by group A β-hemolytic streptococcal (GAS) infection. RF diagnosis is clinical and based on revised Jones criteria. The first version of the criteria was developed by T. Duckett Jones in 1944, then subsequently revised by the American Heart Association (AHA) in 1992 and 2015. However, RF remains a diagnostic challenge for clinicians because of the lack of specific clinical or laboratory findings. As a result, it has been difficult for some time to maintain a balance between over- and underdiagnosis of RF cases. The Jones criteria were revised in 2015 by the AHA, and the main modifications were as follows: the population was subdivided into moderate- to high-risk and low risk; the concept of subclinical carditis was introduced; and monoarthritis was included as a feature of musculoskeletal inflammation in the moderate- to high-risk population. This review will highlight the major changes in the AHA 2015 revised Jones criteria for pediatricians and general practitioners.