Streptococcus Milleri Research Articles

Clinical and radiological characteristics of odontogenic orbital cellulitis

PurposeTo assess the radiological features and clinical outcomes of odontogenic orbital cellulitis.MethodMulti-centre retrospective study of odontogenic orbital cellulitis. Primary outcomes assessed were causal organism(s), clinical signs, radiological findings, management and visual outcomes.ResultsFour patients with odontogenic orbital cellulitis were identified for inclusion. There was an equal proportion of men and women with a mean age of 43 years (range 25–56 years). All patients presented with an orbital compartment syndrome, with visual acuity of counting fingers (n = 1, 25%), hand movements (n = 1, 25%) and no perception of light (n = 2, 50%). The organisms implicated were Streptococcus milleri (n = 3, 75%) and Streptococcus constellatus (n = 1, 25%). MRI findings showed a subperiosteal abscess was present in all cases, which was characterised radiologically as a T1-hyperintense, T2 minimally hyperintense collection with restricted diffusion and a low apparent diffusion coefficient signal. Final visual acuity ranged from 6/6 to no light perception. One patient required an orbital exenteration due to extensive necrosis with sepsis and systemic deterioration.ConclusionsOdontogenic orbital cellulitis carries a serious risk of vision loss with a propensity to present with an orbital compartment syndrome secondary to Streptococcus species. Outcomes were highly variable, with two cases progressing to blindness of which one required an orbital exenteration.

Streptococcus constellatus appendicitis in children: A case series

AbstractBackgroundStreptococcus constellatus (SC) is a pathogen well‐known for its involvement in pyogenic infections, with a notable preference for manifesting within the oral cavity, head and neck, and abdomen. This bacterium, belonging to the Streptococcus milleri group, has garnered attention for its propensity to incite inflammatory processes, especially in the abdominal region.ObjectivesThis study aims to present and characterise nine cases of paediatric patients with SC appendicitis.MethodsWe conducted a report on nine cases of SC appendicitis, all of whom presented to the emergency room with typical symptoms of appendicitis.ResultsPatients diagnosed with SC appendicitis exhibited a severe clinical course, necessitating appendectomy at presentation and requiring prolonged parenteral antimicrobial therapy. Furthermore, a higher readmission rate was observed among these patients, even several months after their initial discharge.ConclusionsSurgeons should be vigilant regarding SC appendicitis and its severe clinical course. Prolonged treatment with antimicrobial agents may be necessary for these patients to achieve better outcomes.

Effect of Lactiplantibacillus plantarum cell-free culture on bacterial pathogens isolated from cystic fibrosis patients: in vitro and in vivo studies.

This study aimed to investigate the effects of the cell-free supernatant of Lactiplantibacillus plantarum ATCC® 10241TM on the biofilm-forming capacity of Pseudomonas aeruginosa strains isolated from cystic fibrosis (CF) patients. In addition, the study evaluated the in vivo potential of the cell-free supernatant to modulate inflammation and reduce lung damage in mice infected with P. aeruginosa strains or co-challenged with P. aeruginosa and the Streptococcus milleri group (SMG). The results showed that CF-derived P. aeruginosa strains can infect the respiratory tract of adult mice, inducing local inflammation and lung damage. The severity of these infections was exacerbated when P. aeruginosa was co-administered with SMG. Notably, nebulization with the cell-free supernatant of L. plantarum produced beneficial effects, reducing respiratory infection severity and inflammatory responses induced by P. aeruginosa, both alone or in combination with SMG. Reduced bacterial loads and lung damage were observed in supernatant-treated mice compared to controls. Although further mechanistic studies are necessary, the results show that the cell-free supernatant of L. plantarum ATCC® 10241TM is an interesting adjuvant alternative to treat P. aeruginosa respiratory infections and superinfections in CF patients.

EP568 - A rare case of necrotizing fasciitis caused by Streptococcus Anginosus and Staphylococcus Lugdunensis

Abstract Necrotizing fasciitis (NF) is a rare soft tissue infection involving the fascial planes, causing rapid and extensive tissue destruction. We present a unique case of NF in a patient with poor glycemic control caused by atypical pathogens. A 66-year-old female with a recent biopsy for a wart-like lesion developed a wound infection, with greenish-black exudate. Initial observations were: temperature: 39.4 degrees, heart rate: 105, GCS: 15/15. Physical examination revealed a grossly filiform lesion below her abdominal apron measuring 7cm in diameter. The patient was empirically treated with IV Co-Amoxiclav. Abnormal biochemistry results are shown below. Microbiological analysis revealed Streptococcus Anginosus, anaerobes and Staphylococcus Lugdunensis. CT abdomen revealed extensive inflammatory changes with gas and fluid collection and enlarged pelvic and inguinal lymph nodes. Two urgent surgical explorations and debridements, with meticulous wound care using negative pressure wound dressings (Prevena) were done. Intravenous Gentamicin, Benzylpenicillin, Clindamycin, Metronidazole and Flucloxacillin were administered for six weeks. The patient's clinical status gradually improved. Streptococcus Anginosus, that is part of the Streptococcus Milleri group and Staphylococcus Lugdunensis, a coagulase-negative Staphylococci (CoNS) are commensal organisms of the oral and gastrointestinal tracts. These organisms possess virulence factors that facilitate tissue invasion and destruction, causing an aggressive course of NF. This case highlights the importance of considering atypical pathogens, especially in patients with predisposing factors such as diabetes and obesity. Early recognition, prompt surgical intervention and a multidisciplinary approach are essential for improving outcomes in these cases.TestResultWhite Blood Cells (WBC)22,200 [WBCs per microliter]Sodium123 [mmol/L]Chloride88 [mmol/L]C-reactive protein (CRP)318 [mg/L]Blood Glucose19.3 [mmol/L]

Ten-year statewide cross-sectional review of pediatric sinogenic intracranial abscess and empyema in Queensland, Australia: microbial profile before and after COVID-19.

Sinogenic intracranial infections in children, such as subdural empyema or intracranial abscess, are a rare disease process with significant associated morbidity. Recent literature has suggested that there may have been an increase in frequency of these infections following the COVID-19 pandemic, but the literature has been conflicting, perhaps related to the heterogenous management of COVID-19 lockdowns in various states and differences in data capture between methods. The collection of statewide Australian data overcomes these limitations by capturing a comprehensive sample though the public healthcare system of patients who were subject to a homogeneous statewide approach to public health policy during the COVID-19 pandemic (population 5.6 million, including 1.3 million children). The objective of this study was to present population-level data to address the question of whether the incidence of intracranial infections changed in pediatric patients before and after the COVID-19 pandemic. The authors present a retrospective 10-year statewide description of sinogenic intracranial infections in Queensland, Australia. A comparison was made between the incidence and microbiological profile before and after the onset of COVID-19 lockdowns on March 22, 2020. Forty-four pediatric intracranial infections undergoing neurosurgical intervention were identified within the review period. After exclusion of postsurgical and cardioembolic causes, 33 sinogenic intracranial infections were included (16 before and 17 after 2020, with a mean annualized incidence of 0.25 vs 0.37 cases per 100,000 children, respectively; p > 0.05). The most frequent organisms identified were Streptococcus milleri (n = 19), polymicrobial (n = 4), and S. aureus (n = 3). No significant differences in antimicrobial profile, susceptibility, parenchymal involvement, or clinical outcome were identified between the pre- and post-COVID-19 groups. No statistically significant differences in the epidemiology of pediatric intracranial infection have occurred in the state of Queensland, Australia, before and after March 22, 2020, and the COVID-19 pandemic.

Undetected permanent dental inflammation as a possible trigger for brain abscesses? A retrospective analysis over the last 2 decades

BackgroundRecently, there is increasing evidence that the proportion of odontogenic brain abscesses is greater than previously known. In this study, we aim to differentiate the oral infections as triggers more precisely and to classify them in the clinical setting.MethodsFor analysis, we conducted a retrospective single center study. We reviewed patients with brain abscesses who have undergone treatment in the University Hospital of Freiburg, Germany in the period between 2000–2021. Inclusion required two main criteria: 1. The brain abscess must not have an other focus than odontogenic. 2. The microbial spectrum identified in the brain abscess must be consistent with an odontogenic origin.ResultsOf 217 brain abscess patients, 26 met the inclusion criteria. 42% (11 patients) suffered from immunosuppressive conditions. Odontogenic foci were diagnosed in 18 cases (69%). Neurologic deficits included vigilance reduction and hemiparesis. Pathogens of the Streptococcus anginosus group were the most frequent causative agent (21 cases, 81%). Metronidazole (54%) and ceftriaxone (42%) were part of the targeted antibiotic therapy. All brain abscesses were surgically treated. Teeth were extracted in 14 of 17 cases for focus control. 18 cases (72%) showed complete or partial resolution of neurologic symptoms and 3 cases were fatal.ConclusionApparently silent or chronic oral infections are sufficient to cause bacterial colonization of the brain, especially in immunocompromised patients. Therefore, special care should be taken to maintain good oral health. An interdisciplinary management should become a standard to prevent and treat the occurrence of brain abscesses.

Increasing Incidence of Streptococcus anginosus Group Intracranial Infections Associated With Sinusitis, Otitis Media, and Mastoiditis in Children.

The Streptococcus anginosus group (SAG) pathogens have the potential to cause head and neck space infections, including intracranial abscesses. Several centers noted an increase in intracranial abscesses in children during the SARS-CoV-2 pandemic, prompting a Centers for Disease Control and Prevention health alert in May 2022. We examined the epidemiology of pediatric intracranial abscesses at a tertiary care center with a focus on SAG pre- and post-pandemic. Cases of intracranial abscesses of any microbiologic etiology admitted from January 2011 to December 2022 were identified using International Classification of Diseases 10 codes. Subjects were cross-referenced with culture results from the microbiology laboratory at Texas Children's Hospital. Cases included were those associated with either otitis media, mastoiditis or sinusitis and medical records were reviewed. A total of 157 cases were identified and 59.9% (n = 94) were caused by SAG. The incidence of all sinogenic/otogenic intracranial infections ( P = 0.002), and SAG-specific infections ( P = 0.004), increased from 2011 to 2022. SAG infection was more often associated with multiple surgeries, and these subjects were more likely to require craniotomy or craniectomy. Among sinogenic abscesses, S. intermedius was the most common pathogen, while among otogenic cases, S. pyogenes predominated. From March 2020 to Dec 2022, 9/49 cases tested positive for SARS-CoV-2 (18.4%); characteristics of infection were not significantly different among cases with and without SARS-CoV-2. Over the last decade, intracranial complications of sinusitis/otitis have been increasing, specifically those caused by SAG; this trend, however, predated the SARS-CoV-2 pandemic. SAG was associated with a greater need for surgical intervention, specifically neurosurgery. Further work is necessary to determine the cause for these rising infections.

Streptolysin S induces proinflammatory cytokine expression in calcium ion-influx-dependent manner

Anginosus group streptococci (AGS) are opportunistic pathogens that reside in the human oral cavity. The β-hemolytic strains of Streptococcus anginosus subsp. anginosus (SAA) produce streptolysin S (SLS), a streptococcal peptide hemolysin. In recent clinical scenarios, AGS, including this species, have frequently been isolated from infections and disorders beyond those in the oral cavity. Consequently, investigating this situation will reveal the potential pathogenicity of AGS to ectopic infections in humans. However, the precise mechanism underlying the cellular response induced by secreted SLS and its relevance to the pathogenicity of AGS strains remain largely unknown. This study aims to elucidate the mechanism underlying the host cellular response of the human acute monocytic leukemia cell line THP-1 to secreted SLS. In THP-1 cells incubated with the culture supernatant of β-hemolytic SAA containing SLS as the sole cytotoxic factor, increased Ca2+ influx and elevated expression of proinflammatory cytokines were observed. Significantly reduced expression of SLS-dependent upregulated cytokine genes under Ca2+-chelating conditions suggests that Ca2+ influx triggers SLS-dependent cellular responses. Furthermore, SLS-dependent enhanced expression of IL-8 was also implicated in the activation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) signaling pathways. The findings presented in this study are crucial for a comprehensive understanding of the real pathogenicity of SLS-producing β-hemolytic AGS in the latest clinical situations.

Prevalence of Bacteremia Due to Streptococcus/Enterococcus Species at an Academic/Community Health System Over a Five Year Period

Abstract Timely surveillance of bacteremia is important for identifying emerging pathogens and to implement effective antimicrobial strategies and public health measures. Organisms in the genera Streptococcus and Enterococcus are often the cause of bacteremia and merit particular attention. The objective of this study was to determine the prevalence of bacteremia caused by several clinically significant Streptococcus species (S. pyogenes, S. agalactiae, S. pneumoniae, S. dysgalactiae/equisimilis, the S. anginosus group (S. anginosus, S. constellatus, S. intermedius), and Enterococcus species (E. faecium and E. faecalis) over a 5 year period (2017-2022). Bacteria isolated from blood culture bottles were identified by MALDI-TOF mass spectrometry (VITEK® MS). Data were obtained from a Laboratory Results Repository in Epic Beaker to include these organisms, isolated in blood cultures (BCs), patient gender, patient age, and the collection date. The data were then consolidated to yield one unique organism per patient per episode. The prevalence of organisms as a percent of the total positive BCs for the overall time period and for each year was determined. Species from the Enterococcus genus were the two most prevalent organisms for each year except for 2017. E. faecalis was the most prevalent overall (57.4%, n = 534) and for each year except for 2020. Combining all analyzed organisms, S. agalactiae was the third most prevalent organism for each year except for 2017 when it was the second and 2020-2021 when it was the fourth. However, within the Streptococcus genus alone, S. agalactiae was the most prevalent (27.5%, n = 281). S. pneumoniae, demonstrating seasonality, was the second most prevalent from 2018-2019, however, it was outranked by S. dysgalactiae/equisimilis from 2020-2022 when it was the fourth and by the S. anginosus group in 2017 and 2020-2022. S. pyogenes was the fourth most prevalent organism in 2017 and the third most in 2018; however, it decreased in subsequent years and was surpassed by all other organisms. Stratified by decade of life, patients in their seventh decade of life (60-69 yr) accounted for the most positive BCs for every organism, except for E. faecalis, followed frequently by patients in their sixth (50-59 yr) and eighth (70-79 yr) decades of life. Patients in their first decade of life (0-9 yr) accounted for a preponderance of positive BCs for E. faecalis, S. agalactiae (highest prevalence <7 days of life), and S. pneumoniae. This study highlighted the relative abundance of bacteremia caused by Enterococcus species. Additionally, it demonstrated the importance of Streptococcus agalactiae bacteremia, especially in the first and seventh decades of life. Finally, this study showed the increasing prevalence of organisms within the Streptococcus anginosus group and Streptococcus dysgalactiae/equisimilis. This analysis demonstrated the dynamics of bacteremia and prevalence among several species within the Enteroccocus and Streptococcus genera.

1692. Increasing incidence of Streptococcus anginosus group intracranial complications of sinusitis, otitis media and mastoiditis in a pediatric population

Abstract Background The Streptococcus anginosus group (SAG) pathogens (S. anginosus, S. intermedius, and S. constellatus) are oral flora with the potential to cause head and neck space infections including brain abscesses. Several centers noted an increase in intracranial abscesses in children in the SARS-CoV-2 era, prompting a CDC health alert in May 2022. Notably, a large proportion of such reported cases were associated with SAG and/or sinusitis. We examined the epidemiology of pediatric intracranial abscesses with a focus on SAG in the pre- and post-pandemic periods. Methods Cases of intracranial abscesses (parenchymal, subdural, epidural) of any microbiologic etiology from January 1, 2011 to December 31, 2022 were identified at Texas Children's Hospital by ICD10 codes. Subjects were cross referenced with culture results of the microbiology laboratory. Cases included were those associated with either otitis media, mastoiditis, or sinusitis. Temporal trend in these infections was investigated with linear regression. Results 157 cases were identified and 59.9% were due to SAG. The incidence of all sinogenic/otogenic intracranial infections (p=0.006), and SAG specific infections (p=0.01), increased from 2011 to 2022 (Figure 1). SAG infection was more often associated with multiple surgeries and these subjects were specifically more likely to require craniotomy or craniectomy (Figure 2). Among sinogenic abscesses, S. intermedius was the most common pathogen while among otogenic cases S. pyogenes predominated (Figure 3). There were 8 cases of craniectomies and one relapse (due to SAG) after replacement of autologous bone flap. After March 2020, 6/46 cases tested positive for SARS-CoV-2 (13%); the severity of infection was not significantly different with concomitant COVID and intracranial abscess. The proportion of SAG-associated infections was similar prior to and after the COVID pandemic. *- p= 0.01- <0.05 ** p< 0.01 Conclusion Over the last decade, intracranial complications of sinusitis/otitis have been increasing, and specifically those caused by SAG. This observed trend clearly predated the COVID pandemic. SAG cases were associated with greater need for surgical intervention and specifically neurosurgery. Further work is necessary to determine the explanation for these rising infections. Disclosures Sheldon L. Kaplan, MD, MeMed: Grant/Research Support|Pfizer: Grant/Research Support|Pfizer: Honoraria Jonathon C. McNeil, MD, Allergan: Grant/Research Support|Nabriva Therapeutics: Grant/Research Support

S treptococcus intermedius and Other Streptococcus anginosus Group Species in Pediatric Cranial and Intracranial Pyogenic Infections.

S treptococcus intermedius and Other Streptococcus anginosus Group Species in Pediatric Cranial and Intracranial Pyogenic Infections.

Brain Abscess Caused by Oral Cavity Bacteria: A Nationwide, Population-based Cohort Study.

Oral cavity bacteria are the most frequent etiology of brain abscess. Yet, data on the clinical presentation and outcome are scarce. We performed a nationwide, population-based study comprising all adults (aged ≥18 years) with brain abscess due to oral cavity bacteria in Denmark from 2007 through 2020. Prognostic factors for unfavorable outcome (Glasgow outcome scale, 1-4) were examined using modified Poisson regression to compute adjusted relative risks (RRs) with 95% confidence intervals (CIs). Among 287 identified patients, the median age was 58 years (interquartile range, 47-66), and 96 of 287 (33%) were female. Preexisting functional impairment was absent or mild in 253 of 280 (90%), and risk factors for brain abscess included immunocompromise in 95 of 287 (33%), dental infection in 68 of 287 (24%), and ear-nose-throat infection in 33 of 287 (12%). Overall, a neurological deficit was present in 246 of 276 (86%) and in combination with headache and fever in 64 of 287 (22%). Identified microorganisms were primarily the Streptococcus anginosus group, Fusobacterium, Actinomyces, and Aggregatibacter spp., and 117 of 287 (41%) were polymicrobial. Unfavorable outcome occurred in 92 of 246 (37%) at 6 months after discharge and was associated with antibiotics before neurosurgery (RR, 3.28; 95% CI, 1.53-7.04), rupture (RR, 1.89; 95% CI, 1.34-2.65), and immunocompromise (RR, 1.80; 95% CI, 1.29-2.51), but not with specific targeted antibiotic regimens. Identified dental infection was associated with favorable prognosis (RR, 0.58; 95% CI, .36-.93). Brain abscess due to oral cavity bacteria often occurred in previously healthy individuals without predisposing dental infections. Important risk factors for unfavorable outcome were rupture and immunocompromise. However, outcome was not associated with specific antibiotic regimens supporting carbapenem-sparing strategies.

Intracranial Empyema in Children: A Single-center Retrospective Case Series.

We conducted a retrospective, observational study of 42 children with intracranial empyema admitted to a pediatric neurosurgical center over a 9-year period. Intracranial empyema is rare, but causes significant morbidity and mortality. Twenty-eight cases had neurosurgical source control, more commonly for subdural collections. Streptococcus anginosus group bacteria are important pathogens in subdural empyema, whose isolation predicts more complicated postoperative courses.

Bugs Behind the Bulging Eyeball: Microbiology and Antibiotic Management in Orbital Cellulitis With or Without Subperiosteal Abscess.

The objective of this study is to describe causative pathogens and current antibiotic management among hospitalized children with orbital cellulitis. This retrospective study, performed at a tertiary care children's health system, included patients up to 18 years old who presented with radiographic evidence of orbital cellulitis from 2012 to 2019. Of the 298 patients included in the study, 103 had surgery and an intraoperative culture obtained. A pathogen was recovered in 86 cultures (83.5%). The most common pathogens were Streptococcus anginosus group (26.2%), Streptococcus pyogenes (11.7%), methicillin-susceptible Staphylococcus aureus (10.7%), and Streptococcus pneumoniae (9.7%). Only 8/194 (4.1%) blood cultures returned positive. Median duration of intravenous antibiotics was 4 days and median total duration was 17 days. The most common empiric regimen prescribed was ceftriaxone and clindamycin (64.1%). Despite low incidence of methicillin-resistant S aureus, empiric antibiotics often consisted of 2 antibiotics to ensure coverage for this bacterium.

Antimicrobial therapy in the management of odontogenic infections: the penicillin-allergic patient

This retrospective analysis was performed to investigate whether clindamycin remains the preferred antibiotic for penicillin-allergic patients with odontogenic infections. The medical records of 311 patients admitted to the study department with odontogenic infections between 2018 and 2022 and treated with either intravenous amoxicillin–clavulanic acid (Augmentin) or intravenous clindamycin were analyzed. The Augmentin-treated group included 268 patients (86.2%) and the clindamycin-treated group included 43 patients (13.8%). Severity parameters did not differ significantly between the two groups, except for a higher prevalence of abscesses in the clindamycin-treated group (58.1% vs 41.0% in the Augmentin-treated group; P = 0.035). The clindamycin-treated group required a longer duration of intravenous antibiotics (P = 0.001) and had a higher rate of treatment failure (14.0% vs 2.2%; P = 0.002) when compared to the Augmentin-treated group, with a seven-fold increased risk of treatment failure. Moreover, significantly more isolated organisms in the clindamycin-treated group were resistant to clindamycin (P = 0.015); these were all Streptococcus anginosus group. Given the higher risk of treatment failure with clindamycin, it is necessary to choose the antibiotic treatment for penicillin-allergic patients carefully. A detailed history and allergy testing followed by combination therapy is recommended, especially in severe cases.

Clinical characteristics and mortality rates of bacteremia caused by Streptococcus anginosus group: A retrospective study of 84 cases at a tertiary hospital in South Korea

The Streptococcus anginosus group (SAG) is a subgroup of viridans streptococci comprising three species: S. anginosus, S. constellatus, and S. intermedius. SAG usually resides in the oral cavity and colonizes the throat, and the gastrointestinal and genitourinary tracts. SAG can form abscesses in various parts of the body; however, the clinical features of SAG infection are not clear. Here, we reviewed the medical records of all SAG bacteremia patients aged over 18 years who were diagnosed between January 2010 and December 2021 at a tertiary university hospital. We then compared clinical characteristics, source of infection, need for surgical or interventional treatment, and 28-day mortality rates among each species of SAG. Differences in percentages between groups were compared using a proportion test, and differences between mean values were assessed using the Kruskal-Wallis test with post-hoc Bonferroni correction. In total, 84 cases of SAG bacteremia (40 S. anginosus cases, 31 S. constellatus cases, and 13 S. intermedius cases) were identified. The most common comorbidity was diabetes mellitus (n = 26, 31%), and the most common source was hepatobiliary infection (n = 30, 35.7%). Polymicrobial bacteremia was observed in 22.6% (19/84) of cases. Twenty-eight day mortality due to S. anginosus bacteremia was 12.5%; no deaths were reported in the S. constellatus and S. intermedius groups. However, the difference among the groups was not significant (p = 0.054). Hepatobiliary infection was the most common source of SAG bacteremia. In addition, S. anginosus bacteremia resulted in more severe disease and higher mortality rates than S. constellatus or S. intermedius bacteremia.

Management of Pyogenic Liver Abscesses: Contemporary Strategies and Challenges.

Pyogenic liver abscesses (PLAs) are a suppurative infection of the hepatic parenchyma responsible for significant morbidity and mortality. PLAs are categorized into a variety of mechanisms: (1) via the portal vein, (2) through the biliary tract, (3) via the hepatic artery, (4) from trauma, (5) contiguously via direct extension, and (6) cryptogenically. The pathogenesis of PLA, which informs treatment, can often be discerned based on host factors, clinical presentation, and causative microorganisms. The Streptococcus anginosus group, hypervirulent Klebsiella pneumoniae , and multidrug-resistant gram-negative pathogens have emerged as microbiologically challenging organisms to treat. The identification of hypervirulent K. pneumoniae should prompt for assessment for metastatic spread and consideration of prolonged antimicrobial treatment. Abdominal imaging is indispensable in characterizing PLAs and facilitating source control interventions. Source control remains the most critical aspect of PLA management, followed by antimicrobial therapy. Empiric antibiotics for PLAs are informed by the suspected etiology of PLA formation. Duration of antimicrobial therapy is individualized and dependent on multiple components, including the success of achieving source control, host factors, mechanism of PLA development, and the illness course of the individual-factoring in clinical, biochemical, and radiographic parameters.

Streptolysin S induces pronounced calcium-ion influx-dependent expression of immediate early genes encoding transcription factors

Anginosus group streptococci (AGS) are opportunistic human pathogens of the oral cavity. The β-hemolytic subgroup of Streptococcus anginosus subsp. anginosus secretes streptolysin S (SLS) and exhibits not only hemolytic activity but also cytotoxicity toward cultured human cell lines. However, the detailed mechanism of action of SLS and the cellular responses of host cells have not yet been fully clarified. To determine the pathogenic potential of SLS-producing β-hemolytic S. anginosus subsp. anginosus, the SLS-dependent response induced in the human oral squamous cell carcinoma HSC-2 cells was investigated to determine the pathogenic potential of SLS-producing β-hemolytic S. anginosus subsp. anginosus. This study revealed that the Ca2+ influx and the expression of immediate early genes (IEGs) encoding transcription factors such as early growth responses (EGRs) and activator protein-1 (AP-1) were greatly increased in HSC-2 cells incubated with the culture supernatant of SLS-producing β-hemolytic S. anginosus subsp. anginosus. Moreover, this SLS-dependent increase in expression was significantly suppressed by Ca2+ chelation, except for jun. These results suggest that SLS caused Ca2+ influx into the cells following greatly enhanced expression of IEG-encoding transcription factors. The results of this study may help in understanding the pathogenicity of SLS-producing AGS.

The impact of social restrictions on the incidence and microbiology of peritonsillar abscess: a retrospective cohort study

ObjectivesWe aimed to explore the impact of social distancing on the incidence and microbiology of peritonsillar abscess (PTA). MethodsWe performed a cross-sectional analysis of all patients with PTA and their microbiological findings in the 2 years preceding versus the 2 years following the COVID-19 lockdown in Denmark (11 March 2020), who were admitted to the Ear-Nose-Throat Department, Aarhus University Hospital. Age-stratified population data for the catchment area were obtained from Statistics Denmark. ResultsThe annual incidence rate was significantly higher in the 2-year period before (21.8 cases/100 000 inhabitants) compared with after (14.9 cases/100 000) the lockdown (p < 0.001). The number of cases with growth of Streptococcus pyogenes was significantly higher in the period before (n = 67) compared with after (n = 28) the lockdown (p < 0.001), whereas the number of cases positive for Fusobacterium necrophorum (n = 60 vs. n = 64) and streptococcus anginosus group (SAG) (n = 37 vs. n = 43) were stabile (p 0.79 and p 0.58, respectively). The relative prevalence of S. pyogenes was significantly higher in the period before (67/246 cultures, 27%) compared with after (28/179, 16%) the lockdown (p 0.007). On the contrary, the relative prevalence of F. necrophorum and SAG is significantly lower before (60/246, 24% and 37/246, 15%) compared with after (64/179, 36% and 43/179, 24%) the lockdown (p 0.013 and p 0.023). DiscussionSocial distancing had a significant impact on the incidence and microbiology of PTA. Our findings suggest that S. pyogenes-positive PTA is highly related to direct social interaction, and represents a contagious pathogen. By contrast, PTA development caused by F. necrophorum and SAG is unrelated to direct social interaction and may be derived from flora imbalance.

Microbial patterns and culture utility in orbital cellulitis

To determine the prevalence and types of pathogens found in children with orbital cellulitis and to evaluate the utility of nonoperative cultures. This was a retrospective cohort study of children with imaging-confirmed orbital cellulitis over a period of 8 years. Outcomes included prevalence and types of organisms, polymicrobial infection, mixed aerobic-anaerobic infection, effect of age, and culture utility. Of 220 children with orbital cellulitis, 112 (51%) had cultures taken; 69 (31%) had surgical intervention. Culture sources for the 112 children with cultures included blood (57 patients [51%]), sinus (53 [47%]), orbit (42 [38%]), brain (6 [5%]), and skin/conjunctiva/lacrimal sac (6 [5%]). Streptococcus anginosus group strains grew in cultures from 19 children (17%); methicillin-sensitive Staphylococcus aureus (MSSA), in 15 (13%); Streptococcus pyogenes, in 12 (11%); methicillin-resistant Staphylococcus aureus (MRSA), in 6 (5%); anaerobic/facultative gram negative rods, in 8 (7%); anaerobic Gram-positive cocci, other Viridans group streptococci, and Streptococci pneumoniae, in 3 (3%) each; and normal respiratory/skin flora, in 23 (21%). Polymicrobial infection (P = 0.08) and anaerobic organisms (P=0.58) did not differ by age (range, 0.1-16.8 years). In all 220 (100%) children, nonoperative cultures were either not obtained (108 [49%]), not helpful in avoiding surgery (69 [31%]), showed no growth (39 [18%]), or grew an organism that did not change management from empiric therapy (4 [2%]). While many organisms may be cultured from children with orbital cellulitis, Streptococcus and MSSA were the most common in our study cohort. MRSA is uncommon, so initial empiric coverage is not necessary. Rates of polymicrobial and anaerobic infection were similar across ages. Our results indicate that nonoperative cultures are not indicated in the initial medical management of orbital cellulitis; in our cohort, they neither resulted in treatment changes nor helped avoid surgery.