Increasing clindamycin resistance in group A streptococcus

Toxin inhibition: Examining tetracyclines, clindamycin, and linezolid

PURPOSE

The purpose of this review is to discuss the role of toxin inhibition in select infections and to provide recommendations for appropriate antimicrobial selection when toxin inhibition is indicated.

SUMMARY

For select organisms, specifically Clostridioides difficile, Staphylococcus aureus, and Streptococcus pyogenes, toxin production plays an integral role in overall disease pathogenesis and progression. Some expert recommendations include utilization of an antimicrobial with toxin inhibition properties as primary or adjunctive therapy for certain infections due to these organisms, but evolving data have made the choice of antitoxin agent less clear. Clindamycin has been the long-standing standard of care agent for toxin inhibition in necrotizing S. aureus and S. pyogenes infections, but linezolid shows promise as an alternative either in the setting of drug shortages or simply when clindamycin is not optimal, while tetracyclines require further study for this indication. The role for adjunctive toxin inhibition in C. difficile infection (CDI) is less defined, as current first-line therapies already have antitoxin properties.

CONCLUSION

Toxin inhibition plays a key role in successful management of patients with infections due to toxin-producing organisms. Adjunctive therapy with a tetracycline could be considered in severe, fulminant CDI, but the associated benefit is variable. The benefit of antitoxin treatment for necrotizing S. aureus and S. pyogenes has been more consistently documented. Recent studies support linezolid as an alternative to clindamycin as an adjunctive S. aureus treatment or as monotherapy when appropriate.

[Necrotizing soft tissue infections]

Necrotizing soft tissue infections are a heterogeneous group of severe infections of the skin, connective tissue and muscles in which necrotic destruction of the tissue occurs at the site of infection. Various bacteria are known as "typical" triggering pathogens and the infection can occur on the entire surface of the body. Necrotizing soft tissue infections are always a time-sensitive emergency associated with high mortality. Many affected patients are critically ill and require treatment in an intensive care unit. The rapid and radical surgical treatment is an essential part of management and in addition an adequate and timely antimicrobial treatment is of great importance. The health consequences for surviving patients are often severe, as extensive soft tissue damage leads to functional impairments. In many cases extensive plastic surgery follow-up is necessary. Therefore, necrotizing soft tissue infections are "complicated" in every phase of the disease and require interprofessional treatment. This review article provides a current overview of various aspects of the diagnostics, treatment and aftercare of necrotizing soft tissue infections.

Dihydrothiazolo ring-fused 2-pyridone antimicrobial compounds treat Streptococcus pyogenes skin and soft tissue infection

We have developed GmPcides from a peptidomimetic dihydrothiazolo ring-fused 2-pyridone scaffold that has antimicrobial activities against a broad spectrum of Gram-positive pathogens. Here, we examine the treatment efficacy of GmPcides using skin and soft tissue infection (SSTI) and biofilm formation models by Streptococcus pyogenes. Screening our compound library for minimal inhibitory (MIC) and minimal bactericidal (MBC) concentrations identified GmPcide PS757 as highly active against S. pyogenes. Treatment of S. pyogenes biofilm with PS757 revealed robust efficacy against all phases of biofilm formation by preventing initial biofilm development, ceasing biofilm maturation and eradicating mature biofilm. In a murine model of S. pyogenes SSTI, subcutaneous delivery of PS757 resulted in reduced levels of tissue damage, decreased bacterial burdens, and accelerated rates of wound healing, which were associated with down-regulation of key virulence factors, including M protein and the SpeB cysteine protease. These data demonstrate that GmPcides show considerable promise for treating S. pyogenes infections.

Efficacy and side-effect profile of tedizolid in the treatment of streptococcal toxic shock syndrome due to clindamycin-resistant Streptococcus pyogenes: A case report

Oxazolidinones, such as tedizolid and linezolid, are bacteriostatic antibiotics that inhibit protein synthesis. Based on the findings from animal studies and their mechanism of action, these antibiotics are considered for managing toxic shock caused by clindamycin-resistant Group A Streptococcus (GAS; Streptococcus pyogenes). However, clinical reports on their usage in such cases are limited. Herein, we report a case of a 67-year-old woman with chronic myeloid leukemia who presented with fever, facial swelling, and myalgia. She was diagnosed with cellulitis and empirically treated with meropenem. Blood culture later revealed GAS, and she was diagnosed with streptococcal toxic shock syndrome. The antibiotic regimen was adjusted based on sensitivity results, with clindamycin initially replaced by linezolid and later switched to tedizolid owing to concerns about potential bone marrow suppression. Her condition improved, and she was discharged 15 days after admission. Therefore, tedizolid may be a safer option for managing toxic shock syndrome in patients with comorbidities that include thrombocytopenia.

Increasing Rate of Fatal Streptococcus pyogenes Bacteriemia-A Challenge for Prompt Diagnosis and Appropriate Therapy in Real Praxis

Streptococcus pyogenes, group A streptococci (GAS) bacteriaemia, is a life-threatening infection with high mortality, requiring fast diagnosis together with the use of appropriate antibiotic therapy as soon as possible. Our study analysed data from 93 patients with GAS bacteraemia at the General University Hospital in Prague between January 2006 and March 2024. In the years 2016-2019 there was an increase in GAS bacteraemia. Mortality in the period 2006-2019 was 21.9%; in the period 2020-2024, the mortality increased to 41.4%, p = 0.08. At the same time, in the post-2020 period, the time from hospital admission to death was reduced from 9.5 days to 3 days. A significant predictor of worse outcome in this period was high levels of procalcitonin, >35.1 µg/L (100% sensitivity and 82.35% specificity), and lactate, >5 mmol/L (90.91% sensitivity and 91.67% specificity). Myoglobin was a significant predictor in both compared periods, the AUC was 0.771, p = 0.044, and the AUC was an even 0.889, p ≤ 0.001, respectively. All isolates of S. pyogenes were susceptible to penicillin, and resistance to clindamycin was 20.3% from 2006-2019 and 10.3% in 2020-2024. Appropriate therapy was initiated in 89.1%. and 96.6%, respectively. We hypothesise that the increase in mortality after 2020 might be due to a decrease in the immune status of the population.

Impact of Pericoronary Microbiota Composition on Course of Recovery after Third Molar Alveotomy

Although the role of microbiota has been investigated in relation to different oral diseases, it is unknown if its composition has any effect on the course of recovery after third molar alveotomy. Our aim was to determine the influence of patient clinical characteristics as well as pericoronary microbiota composition on the course of recovery after a semi-impacted third molar alveotomy. Thirty-six patients were included and samples obtained with paper points, swabs, and tissue samples were analyzed using DNA hybridization and culture methods. Among the 295 organisms detected, the most frequent were Streptococcus spp. (22.4%; 66/295) followed by Fusobacterium spp. (11.9%; 35/295), and T. forsythia (9.1%; 27/295). A comparison of microbiota composition in patients with better and worse recovery did not show significant differences. Worse recovery outcomes were more frequent in patients with a grade 2 self-assessment of oral health (p = 0.040) and better recovery courses were observed in patients with a grade 4 self-assessment (p = 0.0200). A worse recovery course was statistically significant more frequently in patients with previous oral surgical procedures (p = 0.019). Although we demonstrate that worse recovery outcomes were more frequent when certain bacteria were detected, there was no statistically significant difference. Further research is needed to identify microbial profiles specific to the development of worse outcomes after a third molar alveotomy.

Rising incidence of severe maxillofacial space infections in Germany

OBJECTIVES

Severe maxillofacial space infection (MSI) as an end stage of dentoalveolar diseases or complication of sialadenitis is a potentially life-threatening disease accompanied by complications including airway obstruction, jugular vein thrombosis, descending mediastinitis, sepsis and acute respiratory distress syndrome. The aim of this study was to analyze the incidence and time trends of severe MSI and potentially influencing factors in the German healthcare system over time.

MATERIALS AND METHODS

Nationwide data regarding the national diagnosis-related-group (DRG) inpatient billing system was received from the German Federal Statistical Office. A retrospective analysis of incidence and time trends of MSI-associated procedures classified with the Operation and Procedure Classification System (OPS), were statistically evaluated using Poisson regression analysis between 2005 and 2022 and were associated with different epidemiological factors.

RESULTS

The total standardized incidence rate of MSI-associated procedures in the observational period 2005-2022 was 9.8 (♀8.2; ♂11.4) per 100,000 person years. For all age groups a significant increase of 46.1% in severe MSI - related surgical interventions was registered within the observational period. The largest increase (120.5%) was found in elderly patients over 80 years. There were significant differences of the incidences of MSI-associated surgeries between the different federal states in Germany.

CONCLUSIONS

Severe MSI are a growing challenge in German health care especially among elderly patients over 80 years.

CLINICAL RELEVANCE

Severe MSI is a promising target for prevention. There should be more focus in primary dental and medical care especially in groups depending on social support.

Dihydrothiazolo ring-fused 2-pyridone antimicrobial compounds treat Streptococcus pyogenes skin and soft tissue infection

We have developed GmPcides from a peptidomimetic dihydrothiazolo ring-fused 2-pyridone scaffold that have antimicrobial activities against a broad-spectrum of Gram-positive pathogens. Here we examine the treatment efficacy of GmPcides using skin and soft tissue infection (SSTI) and biofilm formation models by Streptococcus pyogenes. Screening our compound library for minimal inhibitory (MIC) and minimal bactericidal (MBC) concentrations identified GmPcide PS757 as highly active against S. pyogenes. Treatment of S. pyogenes biofilm with PS757 revealed robust efficacy against all phases of biofilm formation by preventing initial biofilm development, ceasing biofilm maturation and eradicating mature biofilm. In a murine model of S. pyogenes SSTI, subcutaneous delivery of PS757 resulted in reduced levels of tissue damage, decreased bacterial burdens and accelerated rates of wound-healing, which were associated with down-regulation of key virulence factors, including M protein and the SpeB cysteine protease. These data demonstrate that GmPcides show considerable promise for treating S. pyogenes infections.

Using antibiotics wisely

PURPOSE OF REVIEW

This review will describe role of shorter antibiotic therapies, early switch from intravenous to oral therapy, and artificial intelligence in infectious diseases.

RECENT FINDINGS

There is evidence that shorter courses of antibiotics are noninferior to standard durations of therapy. This has been demonstrated with Enterobacterales bacteremia that can be treated with 7 days of therapy, community acquired pneumonia with 3 days and ventilator associated pneumonia with just 7 days of antibiotic therapy. The conversion from intravenous to oral therapy in treating bacteremia, endocarditis and bone and joint infections is safe and effective and reduces line complications and costs. Also, for clean surgical procedures only one dose of antibiotic is needed, but it should be the most effective antibiotic which is cefazolin. This means avoiding clindamycin, removing penicillin allergies where possible for improved outcomes. Finally, the role of artificial intelligence to incorporate into using antibiotics wisely is rapidly emerging but is still in early stages.

SUMMARY

In using antibiotics wisely, targeting such as durations of therapy and conversion from intravenous antibiotic therapy to oral are low hanging fruit. The future of artificial intelligence could automate a lot of this work and is exciting but needs to be proven.

VIDEO ABSTRACT

http://links.lww.com/COID/A50.

Antibiotic Myths for the Infectious Diseases Clinician

Antimicrobials are commonly prescribed and often misunderstood. With more than 50% of hospitalized patients receiving an antimicrobial agent at any point in time, judicious and optimal use of these drugs is paramount to advancing patient care. This narrative will focus on myths relevant to nuanced consultation from infectious diseases specialists, particularly surrounding specific considerations for a variety of antibiotics.

Effectiveness of intravenous immunoglobulin therapy for invasive group A Streptococcus infection: A Japanese nationwide observational study

OBJECTIVES

Invasive group A Streptococcus infection (iGAS) is a rare but fatal condition. We aimed to evaluate the effectiveness of intravenous immunoglobulin (IVIG) in the treatment of iGAS.

METHODS

Patients' data were extracted from a Japanese nationwide database between April 2018 and March 2021. The primary outcome was in-hospital mortality rate, whereas the secondary outcomes were 30-day and 7-day mortality rates.

RESULTS

Overall, 481 patients (median age, 65 years; female, 49.7%) were included in the analysis. The overall mortality rate was 31.0%. After adjusting for background factors, we found that IVIG treatment had no effect on in-hospital mortality (adjusted odds ratio [OR]: 0.99, 95% confidence interval [CI]: 0.93-1.04, P = 0.92). Similar results were obtained after propensity score matching (OR: 1.00, 95% CI: 0.62-1.61, P >0.99). The 7-day and 30-day mortality rates were not associated with IVIG treatment.

CONCLUSION

IVIG administration had no survival benefit in iGAS patients. However, these overall findings should not be extrapolated to streptococcal toxic shock syndrome as the effect of IVIG therapy in this condition remains uncertain. Considering the rarity of iGAS, conducting a randomized controlled trial may be impractical. Therefore, an equivalent or more extensive observational study is warranted to validate these findings.

Acute bacterial lymphadenitis in children: a retrospective, cross-sectional study

Acute bacterial lymphadenitis is a common childhood condition, yet there remains considerable variability in antibiotic treatment choice, particularly in settings with low prevalence of methicillin-resistant Staphylococcus aureus such as Europe and Australasia. This retrospective cross-sectional study reviewed children presenting with acute bacterial lymphadenitis to a tertiary paediatric hospital in Australia between 1 October 2018 and 30 September 2020. Treatment approaches were analysed with respect to children with complicated versus uncomplicated disease. A total of 148 children were included in the study, encompassing 25 patients with complicated disease and 123 with uncomplicated lymphadenitis, as defined by the presence or absence of an associated abscess or collection. In culture-positive cases, methicillin-susceptible S. aureus (49%) and Group A Streptococcus (43%) predominated, while methicillin-resistant S. aureus was seen in a minority of cases (6%). Children with complicated disease generally presented later and had a prolonged length of stay, longer durations of antibiotics, and higher frequency of surgical intervention. Beta-lactam therapy (predominantly flucloxacillin or first-generation cephalosporins) formed the mainstay of therapy for uncomplicated disease, while treatment of complicated disease was more variable with higher rates of clindamycin use.    Conclusion: Uncomplicated lymphadenitis can be managed with narrow-spectrum beta-lactam therapy (such as flucloxacillin) with low rates of relapse or complications. In complicated disease, early imaging, prompt surgical intervention, and infectious diseases consultation are recommended to guide antibiotic therapy. Prospective randomised trials are needed to guide optimal antibiotic choice and duration in children presenting with acute bacterial lymphadenitis, particularly in association with abscess formation, and to promote uniformity in treatment approaches. What is Known: • Acute bacterial lymphadenitis is a common childhood infection. • Antibiotic prescribing practices are highly variable in bacterial lymphadenitis. What is New: • Uncomplicated bacterial lymphadenitis in children can be managed with single agent narrow-spectrum beta-lactam therapy in low-MRSA prevalence settings. • Further trials are needed to ascertain optimal treatment duration and the role of clindamycin in complicated disease.

Development of Adapalene Loaded Liposome Based Gel for Acne

Retinoids are considered the mainstay treatment for moderate to severe acne. Adapalene, a third-generation retinoid, has physiochemical properties which hinder the effective delivery of the drug to the skin. Therefore, the current study aimed to develop and evaluate adapalene liposomal loaded gel (ADA-LP gel) for the effective management of acne to improve tolerability and delivery to targeted sites as compared to the conventional dosage form of the drug. A novel spontaneous phase transition method (SPT) was used to formulate liposomes. Liposomal formulation (ADA-LP) was prepared and optimized based on particle size, zeta potential, and PDI. Optimized formulation was further characterized by different techniques and loaded into Carbopol gel. In vitro drug release, ex vivo permeation, and in vivo studies were performed using the prepared adapalene-loaded liposomal-based gel. The in vivo study was done employing the testosterone-induced acne model in mice. The optimized formulation had a size of 181 nm, PDI 0.145, and a zeta potential of -35 mV, indicating that the formulation was stable. Encapsulation efficiency was 89.69 ± 0.5%. ADA-LPs were loaded into the gel. Prepared ADA-LP showed a 79 ± 0.02% release of drug in a sustained manner, within 24 h. The ex vivo permeability study showed a total of 43 ± 0.06 µg/cm² of drug able to permeate through the skin within 24 h. Moreover, only 28.27 ± 0.04% was retained on the epidermis. The developed ADA-LP gel showed significant improvement in the acne lesions in mice with no visible scars and inflammation on the skin. Therefore, ADA-LP-based gel could be a promising carrier system for the safe and effective delivery of Adapalene.

Should Linezolid Replace Clindamycin as the Adjunctive Antimicrobial of Choice in Group A Streptococcal Necrotizing Soft Tissue Infection and Toxic Shock Syndrome? A Focused Debate

Group A Streptococcus (GAS) necrotizing soft tissue infections and toxic shock syndrome remain high-mortality conditions. In vitro and animal model data, as well as multiple observational studies, suggest adjunctive clindamycin (ie, given with a beta-lactam) reduces invasive GAS infection mortality by inhibiting exotoxin production. Unfortunately, clindamycin resistance in GAS has been rapidly increasing in the United States since the mid-2010s, although the clinical significance of this remains unclear. Linezolid is a promising alternative adjunctive agent to which US GAS isolates remain near-universally susceptible, with a similar mechanism of action and similar in vitro evidence of GAS virulence factor attenuation. However, the clinical data supporting linezolid's value in severe GAS infections are far more limited. Here the authors review the data and reasoning behind a general preference for clindamycin or linezolid in a focused, pro-con debate format.