Search Results (207)

Guillain-Barre syndrome is an autoimmune disease that provokes neural illness causing acute paralysis neuropathy. This syndrome appears after some bacterial infections produced by Campylobacter jejuni, Streptococcus pyogenes, S. pneumoniae, Haemophilus influenciae, E. coli and current studies showed the appears of this syndrome after SARS-CoV-2 infection. In this study, a in silico analysis was carry out in which to determinate bacterial epitopes than produce the molecule mimicry phenomena and that can produce the immune system activation against this epitope. A conserved amino acid sequence has been encountered with the highest probability to activate the immune system against this bacterial epitope, human gliomedin and ryanodine 3 type receptor. More studies needed to demonstrate in vivo the molecular mimicry in Guillain-Barre syndrome patients. Full article

Streptococcus pyogenes is a bacterial pathogen known to be the causative agent in many different illnesses, with Group A Streptococcus (GAS) pharyngitis (strep throat), being one of the more prevalent. The spread and severity of GAS pharyngitis can grow exponentially if individuals are not taking the proper precautions. Wastewater surveillance has been used to test for numerous different pathogens that humans spread throughout a community and in this study, we utilized wastewater surveillance to monitor GAS pharyngitis in a small city. Over a year, 57 wastewater influent samples were tested for S. pyogenes and three commonly tested respiratory viruses (Respiratory Syncytial Virus (RSV), SARS-CoV-2, Influenza A). Three microbial indicators and population normalizers (CrAssphage, Pepper mild mottle virus (PMMoV), and Mycobacterium) were tested as well to compare and contrast each indicator’s value and range over time. Wastewater data was then compared to publicly available search term data as clinical data was not readily available. There was a high correlation between the collected molecular data and the publicly available search term data for Streptococcus pyogenes. Additionally, this study provided more information about the seasonal trend of S. pyogenes throughout the year through molecular data and allowed for the ability to track peak infection months in this small city. Overall, these results highlight the substantial benefits of using wastewater surveillance for the monitoring of GAS pharyngitis. This study also provides helpful insights into future studies about the prevalence of respiratory bacteria and their seasonal trends in wastewater, allowing for public health systems to provide mitigation strategies. Full article

Background/Objectives: Meningitis due to the species Streptococcus is a severe central nervous system infection caused by various microorganisms belonging to Streptococcus spp. Its accurate identification is critical for effective clinical management. This study aimed to identify Streptococcus spp. causing meningitis in Greece over a nine-year period using PCR and sequencing-based methods. Methods: A total of 189 clinical samples, collected between 2015 and 2024 from patients suffering from meningitis and/or septicemia, were analyzed by the use of a combination of multiplex polymerase chain reaction (PCR) assays and tuf gene sequencing for further species identification. Results: Sample analysis identified 70 samples as S. pyogenes (18.52%) (GAS) and S. agalactiae (18.52%) (GBS), while 119 (62.96%) were recorded as non-typable Streptococcus spp. Further analysis using sequencing methods revealed that the most frequent Streptococcus spp. belonged to the mitis group (42.86%) and the pyogenic group (20.17%). A higher prevalence was observed in children aged 0–14 years old and adults over 50 years old. Conclusions: This study highlights the use of molecular diagnostics in identifying other Streptococcus spp., providing insights into age-related susceptibility and epidemiological trends. Future studies are needed to explore the pathogenic role of the identified Lactococcus spp. Full article

Amelanotic melanocytic nevi of the oral cavity are uncommon lesions that often present a diagnostic challenge for clinicians, primarily due to their nonspecific clinical appearance and the broad spectrum of possible differential diagnoses. These lesions can mimic a variety of benign and malignant conditions, requiring precise histopathological confirmation. The primary objective of this article is to present a comprehensive case report—tracing the course from initial presentation through diagnostic workup to final diagnosis—and to provide an overview of the current literature on oral amelanotic melanocytic nevi. We report the case of a 27-year-old female who presented with a small, exophytic mass located in the anterior mandibular gingival region. The lesion was asymptomatic and lacked pigmentation, adding to the diagnostic uncertainty. A range of differential diagnoses was considered, including pyogenic granuloma, peripheral ossifying fibroma, and squamous cell carcinoma. Due to the lesion’s limited size and accessibility, an excisional biopsy was performed under local anesthesia. Histopathological examination revealed an amelanotic melanocytic nevus, a rare variant characterized by the absence of melanin pigment, further complicating the clinical impression. The diagnosis was confirmed through immunohistochemical staining, which demonstrated melanocytic markers consistent with a nevus. The patient was followed up with for six months postoperatively, with no evidence of recurrence or malignant transformation. This case highlights the critical role of biopsy in achieving a definitive diagnosis, especially in lesions with atypical clinical presentations. It also underscores the importance of considering amelanotic melanocytic nevi in the differential diagnosis of nonpigmented oral lesions, as well as maintaining vigilance regarding the rare possibility of amelanotic melanoma. Full article

Group A β-hemolytic Streptococcus (GAS) is a Gram-positive, coccoid-shaped bacterium that tends to grow in chains; it is a non-spore-forming, facultatively anaerobic, catalase-negative, aerobic bacterium. It is known to cause a wide range of infections in children, ranging from mild upper respiratory tract infections, such as pharyngitis, to severe invasive disease. GAS also notably triggers post-infectious immune sequelae, including acute poststreptococcal glomerulonephritis (APSGN), acute rheumatic fever (ARF), and rheumatic heart disease (RHD), which are major health burdens, especially in low-income countries. In this review, we will present the general characteristics of GAS, highlighting its structural and microbiological features. We will also discuss its pathogenetic mechanisms, especially molecular mimicry, and its ability to cause autoimmune responses. Finally, we will elucidate some of the autoimmune sequelae that mark GAS infections, such as ARF, RHD, APSGN, and guttate psoriasis. Understanding GAS as a model pathogen for infection-induced autoimmunity provides insight into host–pathogen interactions and supports the development of targeted interventions. Emphasis on early diagnosis and antibiotic treatment is essential to reduce the burden of autoimmune complications Full article

Periodontal abscesses are a frequent health problem found in pet rabbits that could lead to severe complications, including life-threatening ones. Trueperella pyogenes is an opportunistic pathogen isolated from pyogenic infections in different animal species, mostly from farm animals such as ruminants and pigs. This study presents the first case of isolation and molecular characterization of T. pyogenes from a periodontal abscess in a pet rabbit. A narrative review concerning the bacteriological aetiology of odontogenic abscesses in rabbits is also presented. The identification of T. pyogenes isolate was obtained based on the phenotypic properties and confirmed by molecular biology methods, i.e., the 16S rRNA gene sequencing and the presence of species-specific pyolysin gene. Furthermore, the pathogenic potential of the isolate was confirmed by the detection of six out of eight studied virulence genes. This report, along with the literature data, confirms that T. pyogenes may be one of the etiological agents of periodontal abscesses in rabbits. However, inadequate laboratory techniques may result in an underestimation of the occurrence of this bacterial species in rabbits. This study showed the need for standardization of the laboratory methods used for extended microbial culture for the clinical samples obtained from periodontal abscesses in rabbits. These procedures should also include the isolation of fastidious pathogens like T. pyogenes. Full article

Background: This study evaluated the polyphenolic composition, antibacterial activity, molecular docking interactions, and pharmacokinetic properties of Romanian oak and fir honeydew honeys. Methods: Spectrophotometric methods quantified total phenolic, flavonoid contents and antioxidant activity, and individual polyphenols were identified via HPLC-MS. Antibacterial efficacy against Gram-positive and Gram-negative bacteria was evaluated by determining the bacterial inhibition percentage and minimum inhibitory concentrations. The bioactive compounds identified via LC-MS analysis were used to further delineate the possible antibacterial activities in silico. Molecular docking was carried out to predict the binding interactions and complex formation of the identified compounds against protein crystal structures of the bacteria used in this study. Additionally, the pharmacokinetic profile of compounds with high inhibitory potential was assessed via ADMET (absorption, Distribution, Metabolism, Excretion, toxicity) predictors to ascertain their value. Results: Fir honeydew honey showed higher total phenolic (844.5 mg GAE/kg) and flavonoid contents (489.01 mg QUE/kg) compared to oak honeydew honey, correlating with more potent antioxidant activity (IC50 = 5.16 mg/mL). In vitro antimicrobial tests indicated a stronger inhibitory effect of fir honeydew honey, especially against Gram-positive strains like S. aureus, S. pyogenes, and L. monocytogenes, alongside certain Gram-negative strains such as E. coli and H. influenzae. Oak honeydew honey displayed selective antimicrobial action, particularly against P. aeruginosa and S. typhimurium. The docking outcomes showed rutin, rosmarinic acid, beta resorcylic acid, quercetin, ferulic acid, and p-coumaric acid have high inhibitory activities characterised by binding affinities and binding interactions against shiga toxin, riboflavin synthase, ATP-binding sugar transporter-like protein, undecaprenyl diphosphate synthase, putative lipoprotein, sortase A, and immunity protein, making them key contributors to the honey’s antimicrobial activity. Moreover, beta-resorcylic acid, quercetin, ferulic acid, and p-coumaric acid revealed interesting ADMET scores that qualify honey to serve as a good antimicrobial agent. Conclusions: These findings support their potential use as natural antibacterial agents and emphasise the value of integrating chemical, biological, and computational approaches for multidisciplinary characterisations. Full article

A comparative evaluation of Moringa oleifera Lam. ethanolic leaf extracts was performed using different extraction methods (maceration or ultrasound-assisted) and the qualitative and quantitative profile of the bioactive compounds contained were further assessed. The antioxidant potential and antimicrobial activity were evaluated, as well as the antiangiogenic effects through in ovo studies. Six ethanolic extracts were tested in this study. Moringa MAC 70% and Moringa US 70% extracts displayed the highest concentration of phenolic compounds and also showed a significant AOA at the highest tested dose. Regarding the antimicrobial effect, the extracts obtained with 70% ethanol (maceration or ultrasound-assisted) had antimicrobial activity against S. aureus, S. pyogenes and E. coli, followed by Candida parapsilosis. On the Pseudomonas aeruginosa strain, the extracts showed no effect. The HET-CAM assay showed that the extracts did not cause any irritation compared to the used positive control. Furthermore, the extracts Moringa MAC 70% and Moringa US 70% did not affect the normal process of blood vessel formation. The data obtained highlights that, from the six tested extracts, the ones obtained with 70% ethanol using maceration and ultrasound-assisted methods (Moringa MAC 70% and Moringa US 70%) showed the highest phenolic content and exhibited the strongest antioxidant activity. The same two extracts did not show signs of irritation in the HET-CAM model. Full article

Bacteroides pyogenes is a Gram-negative obligate anaerobe rod. It is naturally found in the oral microbiome of cats and dogs, which represents a primary source of disease for humans. The present review provides an update on the role of B. pyogenes as a pathogen responsible for infections in humans. Indeed, an increasing number of B. pyogenes infections have been reported in recent years, including skin and soft tissue infections as well as severe diseases like osteomyelitis, Lemierre’s syndrome, and bloodstream infection. Pre-analytical and analytical phases are crucial to guarantee the isolation of anaerobic bacteria, including B. pyogenes. Moreover, the introduction of MALDI-TOF mass spectrometry and 16S rRNA sequencing in clinical microbiology laboratories may be partially responsible for the increasing number of reports of B. pyogenes infections. However, the mechanisms underlying the pathogenicity of B. pyogenes remain poorly understood and require further investigations. Indeed, despite common antimicrobial susceptibilities, infections frequently persist and require multiple courses of antibiotics. In addition, based on literature data, this review indicates that treatment of skin and soft tissue infections often necessitates surgical procedures and hospitalization. Full article

The study of bacteriocins has significantly enhanced our understanding of microbial interactions, notably within the genus Streptococcus. Among the most functionally diverse and clinically relevant bacteriocins are those belonging to the lantibiotic class, which exhibit potent antimicrobial properties and are central to the competitive dynamics of streptococcal species. This review focuses on the discovery and characterization of bacteriocins produced by Streptococcus pyogenes and Streptococcus salivarius, emphasizing their biological significance within their exclusive human host. A cornerstone of these studies has been the development and application of the pioneer agar culture-based bacteriocin detection methodology, known as streptococcal bacteriocin fingerprinting. This approach has proven invaluable for the initial detection and differentiation of a wide array of bacteriocin-like inhibitory substances (BLIS) in streptococcal populations. A central theme of this review is the diverse biological roles of lantibiotics in S. pyogenes and S. salivarius, particularly in relation to microbial competition, colonization dynamics, and host interactions. The expression of lantibiotic determinants provides distinct advantages to the producing strain, including enhanced niche establishment and the ability to suppress competing microbes. Furthermore, the presence of specific lantibiotic immunity mechanisms safeguards the producer from self-inhibition and potential antagonism from closely related competitors. In S. pyogenes, lantibiotic production has been implicated in virulence modulation, raising important questions about its role in pathogenicity and host immune evasion. Conversely, S. salivarius, a prominent commensal and probiotic candidate species, utilizes its lantibiotic arsenal to confer colonization benefits and mediate beneficial interactions, especially within the oral and upper respiratory tract microbiomes. The implications of in situ lantibiotic expression extend beyond microbial ecology, presenting opportunities for innovative probiotic and therapeutic applications. The potential for harnessing bacteriocin-producing streptococci in antimicrobial interventions, particularly in combating antibiotic-resistant pathogens, underscores the translational relevance of these findings. This review integrates historical and contemporary perspectives on streptococcal bacteriocin research, providing insights into future avenues for leveraging these bioactive peptides in clinical and biotechnological contexts. Full article

Cervical pyogenic spondylitis (CPS) is a rare but serious spinal infection with a high risk of neurological compromise due to the cervical spine’s narrow canal and proximity to critical neurovascular structures. Early diagnosis relies on a high index of suspicion supported by MRI, inflammatory markers, blood cultures, and tissue biopsy. Empirical intravenous antibiotics remain the cornerstone of initial treatment, followed by pathogen-specific therapy. Surgical intervention is indicated in cases of neurological deterioration, spinal instability, or failure of conservative management. Anterior approaches, including anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF), are widely used, with anterior plating providing biomechanical advantages in select cases. Posterior or combined anterior–posterior approaches are recommended in multilevel disease, deformity, or posterior element involvement. Graft selection—typically autograft or titanium/PEEK cages—must consider infection severity and biomechanical demands. Challenges in CPS management include optimal debridement extent, graft choice in infected environments, the standardization of antibiotic protocols, and the prevention of recurrence. This narrative review synthesizes the cervical-spine-specific literature on diagnosis, treatment strategies, surgical techniques, and postoperative care and proposes the following practical clinical guidance: (1) early MRI for timely diagnosis, (2) prompt surgical intervention in patients with neurological deficits or mechanical instability, and (3) individualized graft selection based on infection severity and bone quality. Full article

Acute otitis media (AOM) is a common disease among children and can be complicated by otorrhea (AOMO). In 2010, the 13-valent Pneumococcal Conjugate Vaccine (PCV13) replaced the 7-valent vaccine (PCV7) in Greece. We aimed to describe the microbiological profile of bacterial ΑOMO among children younger than 16 years across the two PCV periods in a tertiary children’s hospital. Middle ear fluid cultures from 2418 children with AOMO were collected from 2007 to 2022. Otopathogens were isolated and tested for antimicrobial susceptibility. Data were compared between the PCV7- (2007–2011) and PCV13-period (2012–2019). The most common otopathogen over the 16-year period was S. pyogenes (35.4%), followed by H. influenzae (33.8%), S. pneumoniae (26.6%), and M. catarrhalis (4.1%). Pneumococcal resistance to cefotaxime and clindamycin significantly increased from 2% to 4.5% (p = 0.019) and 16.1% to 22.8% (p = 0.039), respectively. Resistance of H. influenzae to ampicillin increased from 6.3% to 13.9% (p < 0.001). A significant reduction in cotrimoxazole-resistant S. pneumoniae from 31% to 22.4% (p = 0.012), and in clindamycin-resistant and erythromycin-resistant S pyogenes, from 17.4% to 9.3% and 21.4% to 10.8%, respectively (p ≤ 0.001), was observed. During 2013–2022, 38 S. pneumoniae serotypes were identified among 250 isolates. Serotype 3 (27.2%) and 19A (13.2%) prevailed, followed by 19F (7%). The most common causes after the shift to PCV13 are S. pyogenes and H. influenzae. However, S. pneumoniae remains an important otopathogen with significant antimicrobial resistance. Serotype 3 was mostly detected, followed by 19A. Full article

Community-acquired infections caused by Klebsiella pneumoniae (K. pneumoniae) have become a significant global health concern, particularly with the emergence of hypervirulent strains (hvKP). These strains are associated with severe infections, such as pyogenic liver abscesses, even in otherwise healthy individuals. Initially reported in Taiwan in the 1980s, hvKP has now spread worldwide. The pathogenicity of hvKP is attributed to an array of virulence factors that enhance its ability to colonize and evade host immune defenses. Additionally, the convergence of hypervirulence with antibiotic resistance has further complicated treatment strategies. As a member of the ESKAPE group of pathogens, K. pneumoniae exhibits high resistance to multiple antibiotics, posing a challenge for healthcare settings. This review provides a comprehensive overview of hvKP, highlighting its structural and pathogenic differences from classical K. pneumoniae strains, key virulence factors, mechanisms of antibiotic resistance, and the increasing threat of multidrug-resistant hvKP. Lastly, we discuss current treatment guidelines and emerging therapeutic strategies to combat this formidable pathogen. Full article

Streptococcus pyogenes meningitis is a rare invasive disease, accounting for less than 2% of bacterial meningitis. We presented two case reports and conducted a systematic review using PUBMED, covering the database from its inception up to 31 December 2024, of pediatric cases of Streptococcus pyogenes meningitis. Only case reports and case series were included. Differences in clinical and laboratory parameters were compared between uneventful course and complicated admissions. A total of 57 cases were included. The median age at diagnosis was 4 years. A primary infection focus outside the brain was identified in 61.39% of cases. S. pyogenes was identified from cerebrospinal fluid in 66.66% of cases and from blood in 15.79%. Septic shock occurred in 24.56% of cases, and 36.84% had brain anatomical anomalies. All patients received broad-spectrum empiric antibiotics, while protein-synthesis inhibitors were administered in 26.31% of cases. A total of 17% of patients died, and 28.07% experienced sequelae. The identification of S. pyogenes from blood and a Phoenix Sepsis Score ≥ 2 were significantly associated with a complicated clinical course. Our findings may offer useful insights for the clinical management of Streptococcus pyogenes meningitis. Full article

Background: Periocular necrotizing fasciitis (PNF) is a rare but life-threatening emergency that requires immediate recognition, as delayed diagnosis can worsen patient outcomes. To address this critical issue, we conducted the largest and most comprehensive systematic review to date, providing valuable insights into the diagnosis and treatment of PNF to improve clinical practice and patient prognosis. Methods: A search on Pubmed, Scopus, Embase, and WOS from January 2013 to August 2024 was performed. Only the cases of NF affecting the periocular region were included with no age limitations. Article selection and data extraction were performed independently by two investigators to avoid bias. Bias on individual studies is low as they represent case reports or case series, and publication bias is partially addressed including all the large case series even if no individual data could be retrieved. Results: The cohort included a total of 183 patients with PNF, with detailed patient-specific data for 107 individuals and only aggregated data for another 76. The average age at diagnosis was 54.2 years, and females constituted 44% of the population sample. Notably, 49.6% of the patients were immunocompromised. Streptococcus pyogenes was the predominant causative organism, identified in 79.8% of the cases. Most infections were unilateral (72.1%) without extension beyond the periocular area (54.7%). Most patients (89.6%) underwent surgical debridement alongside intravenous antibiotics. Septic shock occurred in 26.8% of the patients, and the overall mortality rate was 4.9%. Visual acuity was unaffected in 67.5% of the patients, though 18.2% progressed to blindness on the affected side. Reconstructive efforts predominantly involved skin grafting, both free and local pedunculate flaps as well as secondary healing in some instances. Conclusions: This systematic review summarizes the understanding of periocular necrotizing fasciitis’ (PNF) demographic trends, clinical manifestations, causative pathogens, and patient outcomes. Vigilance for PNF should be heightened when the clinical assessment of the patient’s eyelids reveals rapidly spreading edema and induration, subcutaneous emphysema, or necrotic bullae and/or eschar. Prompt identification and expedited intervention, including debridement and targeted antibiotic therapy, critically influence prognosis. Despite optimal management, patients may still suffer from significant aesthetic impairment, severe complications such as vision loss, or death due to septic shock. Full article