Meningitis and septic shock caused by Streptococcus dysgalactiae subsp. equisimilis

Diagnosis of Neurological Involvement Caused by Streptococcus dysgalactiae: A Case Report and Review of the Literature

Purpose

This study investigated the clinical relevance, pathogenic mechanisms, and neurological involvement of Streptococcus dysgalactiae subspecies equisimilis (SDSE) and subspecies dysgalactiae (SDSD), with a focus on a severe case of SDSE meningitis complicated by septic shock.

Patients and Methods

A systematic review of 19 cases of neurological infections caused by S. dysgalactiae (SDSE or SDSD) from 1971 to 2023 was conducted, supplemented by a detailed case report. Data on patient demographics, predisposing factors, clinical manifestations, diagnostic procedures, treatment, and outcomes were analyzed.

Results

The reviewed cases involved 12 patients with SDSE and seven with SDSD. The median age was 53 years, and most patients had underlying conditions such as diabetes, malignancy, or cardiovascular disease. Neurological manifestations were common, with meningitis being diagnosed in 17 patients. Despite prompt antibiotic therapy, six patients (32%) died, highlighting the severe nature of these infections.

Conclusion

S. dysgalactiae can cause severe neurological infections, particularly in immunocompromised patients. Early recognition and aggressive treatment are essential to improving outcomes. Advanced molecular diagnostic techniques, such as next-generation sequencing (NGS), are crucial in identifying and managing these infections.

Identification and Characterization of a Novel Prophage Lysin against Streptococcus dysgalactiae

Streptococcus dysgalactiae infection can cause bovine mastitis and lead to huge economic losses for the dairy industry. The abuse of antibiotics has resulted in growing drug resistance of S. dysgalactiae, which causes hard-to-treat infections. Bacteriophage lysin, as a novel antibacterial agent, has great potential for application against drug-resistant gram-positive bacteria. However, few studies have been conducted on the prophage lysin of S. dysgalactiae. In this study, we mined a novel prophage lysin, named Lys1644, from a clinical S. dysgalactiae isolate by genome sequencing and bioinformatic analysis. Lys1644 was expressed and purified, and the lytic activity, antibacterial spectrum, optimal pH and temperature, lytic activity in milk in vitro, and synergistic bacteriostasis with antibiotics were assessed. The Lys1644 prophage lysin showed high bacteriolysis activity specifically on S. dysgalactiae, which resulted in CFU 100-fold reduction in milk. Moreover, Lys1644 maintained high activity over a wide pH range (pH 5-10) and a wide temperature range (4-42 °C). Synergistic bacteriostatic experiments showed that the combination of low-dose Lys1644 (50 μg/mL) with a subinhibitory concentration of aminoglycoside antibiotics (kanamycin or spectinomycin) can completely inhibit bacterial growth, suggesting that the combination of Lys1644 and antibiotics could be an effective therapeutic strategy against S. dysgalactiae infection.

Epidemiological and Clinical Features of Streptococcus dysgalactiae ssp. equisimilis stG62647 and Other emm Types in Germany

(1) Background: Streptococcus dysgalactiae subspecies equisimilis (SDSE) is an important β-hemolytic pathogen historically described as mainly affecting animals. Studies epidemiologically assessing the pathogenicity in the human population in Germany are rare. (2) Methods: the present study combines national surveillance data from 2010 to 2022 with a single-center clinical study conducted from 2016 to 2022, focusing on emm type, Lancefield antigen, antimicrobial resistance, patient characteristics, disease severity, and clinical infection markers. (3) Results: The nationwide reported invasive SDSE infections suggest an increasing infection burden for the German population. One particular emm type, stG62647, increased over the study period, being the dominant type in both study cohorts, suggesting a mutation-driven outbreak of a virulent clone. The patient data show that men were more affected than women, although in the single-center cohort, this trend was reversed for patients with stG62647 SDSE. Men affected by stG62647 developed predominantly fascial infections, whereas women suffering from superficial and fascial non-stG62647 SDSE infections were significantly younger than other patients. Increasing age was a general risk factor for invasive SDSE infections. (4) Conclusions: further studies are needed to further elucidate the raised questions regarding outbreak origin, underlying molecular mechanisms as well as sex-dependent pathogen adaptation.

Rare case of bilateral blindness caused by Streptococcus dysgalactiae spp equisimilis endophthalmitis in the setting of meningitis

Endogenous endophthalmitis (EE) is a rare infectious disease of the intraocular tissues with a major risk of significant visual loss. We describe a case of a female patient who presented with altered mental status and vision loss. The patient was found to have bacteraemia, meningitis and bilateral EE caused by Streptococcus dysgalactiae spp equisimilis The patient was clinically stabilised but continued to demonstrate profound visual loss at 5-month follow-up. To our knowledge, this is the first case report of this organism causing meningitis complicated by EE. Furthermore, this infection may have heralded a diagnosis of cancer.

Pathogenicity and drug resistance of animal streptococci responsible for human infections

Bacteria of the genus Streptococcus, earlier considered typically animal, currently have also been causing infections in humans. It is necessary to make clinicians aware of the emergence of new species that may cause the development of human diseases. There is an increasing frequency of isolation of streptococci such as S. suis, S. dysgalactiae, S. iniae and S. equi from people. Isolation of Streptococcus bovis/Streptococcus equinus complex bacteria has also been reported. The streptococcal species described in this review are gaining new properties and virulence factors by which they can thrive in new environments. It shows the potential of these bacteria to changes in the genome and the settlement of new hosts. Information is presented on clinical cases that concern streptococcus species belonging to the groups Bovis, Pyogenic and Suis. We also present the antibiotic resistance profiles of these bacteria. The emerging resistance to β-lactams has been reported. In this review, the classification, clinical characteristics and antibiotic resistance of groups and species of streptococci considered as animal pathogens are summarized.