Clinical and prognostic differences between methicillin-resistant and methicillin-susceptible Staphylococcus aureus infective endocarditis

Clinical features and prognosis of prosthetic valve endocarditis due to Staphylococcus aureus

PURPOSE

Staphylococcus aureus prosthetic valve endocarditis (SAPVE) is a serious infection with high mortality. The main objective of this study was to identify factors associated with in-hospital mortality.

METHODS

From January 2008 to December 2021, consecutive patients from a Spanish cohort of infective endocarditis with a definitive diagnosis of SAPVE were analyzed.

RESULTS

During the study period, 219 cases of definitive SAPVE were diagnosed, which accounted for 16.7% of a total of 1309 cases of definitive prosthetic valve endocarditis (PVE). Patients presented advanced age and marked comorbidity. There was a higher incidence of persistent bacteremia, septic shock, stroke, and acute kidney injury than in cases of PVE caused by other microorganisms. Methicillin resistance was not associated with differences in clinical presentation, echocardiographic findings, or mortality. Only 50.6% of the patients with surgical indications (88 patients) underwent surgery. Overall, in-hospital mortality was 47.9%. The variables associated with in-hospital mortality were age (OR:1.03, 95% CI: 1.00-1.05; p = 0.016), heart failure (OR:2.86, 95% CI: 1.53-5.32; p = 0.001), acute kidney injury (OR:2.42, 95%CI:1.28-4.58; p = 0.006), stroke (OR:3.53, 95%CI:1.79-6.96; p < 0.001) and surgery indicated but not performed (OR:2.01, 95%CI:1.06-3.8; p = 0.030). On the other hand, the performance of surgery per se in patients with SAPVE, regardless of whether there was a surgical indication according to the guidelines, was not associated with a reduction in in-hospital mortality.

CONCLUSIONS

SAPVE is characterized by high mortality, which is more marked in patients who present a surgical indication but do not undergo surgery.

Epidemiological differences, clinical aspects, and short-term prognosis of patients with healthcare-associated and community-acquired infective endocarditis

Background

The prevalence of healthcare-associated infective endocarditis in Brazil is poorly known.

Aim

To analyze the epidemiological, clinical and microbiological characteristics, and the prognosis of healthcare-associated infective endocarditis (HAIE) compared with community-acquired infective endocarditis (CIE) and identify the associated factors with hospital mortality.

Method

A historical cohort study was carried out, with a data collection period from January 2009 to December 2019 at the Federal University of São Paulo. Data were collected from medical records of patients with infective endocarditis (IE) hospitalized during the study period. Patients were classified into three groups: CIE, non-nosocomial HAIE (NN-HAIE) and nosocomial HAIE (NHAIE).

Results

A total of 204 patients with IE were included; of these, 127 (62.3%) were cases of HAIE, of which 83 (40.7%) were NN-HAIE and 44 (21.6%) were NHAIE. Staphylococcus spp. Were the main causative agents, especially in HAIE groups (P<0.001). Streptococcus spp. were more prevalent in the CIE group (P<0.001). In-hospital mortality was 44.6%, with no differences between groups. Independent risk factors for in-hospital mortality were age ≥ 60 years (odds ratio (OR): 6.742), septic shock (OR 5.264), stroke (OR 3.576), heart failure (OR 7.296), and Intensive Care Unit admission (OR 7.768).

Conclusion

HAIE accounted for most cases in this cohort, with a higher prevalence of non-nosocomial infections. Staphylococcus spp. were the main causative agents. Hospital mortality was high, 44.6%, with no difference between groups.

Ceft-to-Ceft Study: Real-Life Experience with Ceftaroline and Ceftobiprole in Treatment of the Principal Infectious Syndromes in a Spanish Multicenter Hospital Cohort

BACKGROUND

To compare the real-life effectiveness and safety of ceftaroline fosamil (ceftaroline-F) and ceftobiprole medocaril (ceftobiprole-M) for infections in hospitalized patients.

METHODS

This comparative, observational, retrospective, and multicenter Spanish study included patients receiving outpatient parenteral antimicrobial therapy (OPAT) and hospitalized patients treated for at least 48 h with ceftaroline-F or ceftobiprole-M between their first incorporation in the clinical protocol of each hospital and 31 July 2022.

RESULTS

Ceftaroline-F was administered to 227 patients and ceftobiprole-M to 212. In comparison to the latter, ceftaroline-F-treated participants were younger (63.02 vs. 66.40 years, OR 1.1; 95%CI: 1.001-1.05) and had higher rates of septic shock (OR 0.27; 95%CI: 0.09-0.81) and higher frequencies of targeted (57.7 vs. 29.7%; OR: 0.35; 95%CI: 0.18-0.69) and combined (89.0 vs. 45.8%, OR: 0.13; 95%CI: 0.06-0.28) therapies that were second line or more (82.4% vs. 64.6%%; OR 0.35; 95%CI: 0.18-0.69), and higher rates of infections due to Gram-positive cocci (92.7 vs. 64.7%, p = 0.001), bacteremia (51.9 vs. 21.7%, p = 0.001), infective endocarditis (24.2 vs. 2.4%, p = 0.0001), and mechanical ventilation-associated pneumonia (8.8 vs. 2.4%, p = 0.0001). Ceftobiprole-M was more frequently administered against polymicrobial infections (38.1 vs. 14.0%, p = 0.001), those produced by Gram-negative bacilli (19.7 vs. 6.0%, p = 0.0001), nosocomial pneumonia (33 vs. 10.6%, p = 0.0001), and skin and soft-tissue infections (25.4 vs. 10.1%, p = 0.0001). Patients treated with ceftaroline-F had a longer hospital stay (36 (IQR: 19-60) vs. 19.50 (IQR: 12-30.75, p = 0.0001) days), with no difference in infection-related mortality at 14 (13.2 vs. 8.0%, p = 0.078) or 28 (4.8 vs. 3.3%, p = 0.415) days or in dropout rate for adverse effects (2.2 vs. 0.9%; p = 1).

CONCLUSIONS

The fifth-generation cephalosporins, ceftaroline-F and ceftobiprole-M, are safe and effective in real life, with no difference between them in health outcomes.

Contemporary use of cefazolin for MSSA infective endocarditis: analysis of a national prospective cohort

OBJECTIVES

This study aimed to assess the real use of cefazolin for methicillin-susceptible Staphylococcus aureus (MSSA) infective endocarditis (IE) in the Spanish National Endocarditis Database (GAMES) and to compare it with antistaphylococcal penicillin (ASP).

METHODS

Prospective cohort study with retrospective analysis of a cohort of MSSA IE treated with cloxacillin and/or cefazolin. Outcomes assessed were relapse; intra-hospital, overall, and endocarditis-related mortality; and adverse events. Risk of renal toxicity with each treatment was evaluated separately.

RESULTS

We included 631 IE episodes caused by MSSA treated with cloxacillin and/or cefazolin. Antibiotic treatment was cloxacillin, cefazolin, or both in 537 (85%), 57 (9%), and 37 (6%) episodes, respectively. Patients treated with cefazolin had significantly higher rates of comorbidities (median Charlson Index 7, P <0.01) and previous renal failure (57.9%, P <0.01). Patients treated with cloxacillin presented higher rates of septic shock (25%, P = 0.033) and new-onset or worsening renal failure (47.3%, P = 0.024) with significantly higher rates of in-hospital mortality (38.5%, P = 0.017). One-year IE-related mortality and rate of relapses were similar between treatment groups. None of the treatments were identified as risk or protective factors.

CONCLUSION

Our results suggest that cefazolin is a valuable option for the treatment of MSSA IE, without differences in 1-year mortality or relapses compared with cloxacillin, and might be considered equally effective.

Methicillin Resistance Increased the Risk of Treatment Failure in Native Joint Septic Arthritis Caused by Staphylococcus aureus

This study aimed to compare clinical characteristics and outcomes in patients with native joint septic arthritis (NJSA) due to methicillin-resistant Staphylococcus aureus (MRSA) in comparison to methicillin-sensitive S. aureus (MSSA) and identify treatment failure risk factors. We conducted a multi-center retrospective study on adult NJSA patients at three teaching hospitals in South Korea from 2005 to 2017. Among 101 patients diagnosed with S. aureus NJSA, 39 (38.6%) had MRSA strains. Compared to MSSA, patients with MRSA had a higher prevalence of nosocomial infections (17.9% vs. 1.6%; p = 0.005) and received inappropriate antibiotics within 48 h more frequently (74.4% vs. 0%; p < 0.001). In total, twenty patients (19.8%) experienced treatment failure, which encompassed five patients (5.0%) who passed away, nine (8.9%) requiring repeated surgical drainage after 30 days of antibiotic therapy, and seven (6.9%) with relapse. The MRSA group showed a higher rate of overall treatment failure (33.3% vs. 11.3%; p = 0.007) with a notably increased frequency of requiring repeated surgical interventions after 30 days of antibiotic therapy (17.9% vs. 3.2%, p = 0.026), in contrast to the MSSA group. Independent risk factors for treatment failure included Charlson comorbidity score, elevated CRP levels, and methicillin resistance. Methicillin resistance is an independent risk factor for treatment failure, emphasizing the need for vigilant monitoring and targeted interventions in MRSA-related NJSA cases.

A Case of Mitral Valve Infective Endocarditis and Atrial Fibrillation Complicated by Hemorrhagic Stroke: A Challenging Clinical Scenario and Approach to Management

This case report presents a rare and intricate clinical scenario involving a 58-year-old male with a history of hypertension, intravenous drug use (IVDU), and cocaine abuse. The patient presented with profound hypotension and symptoms suggestive of impending shock. Septic workup revealed Staphylococcus aureus in all four blood culture bottles, confirming a diagnosis of infective endocarditis (IE). Transthoracic echocardiography demonstrated a large vegetation measuring 1.9x1.7 cm on the mitral valve. Additionally, the patient exhibited non-ST segment elevated myocardial infarction (NSTEMI) type II in the setting of cocaine use, atrial fibrillation, and therapeutic anticoagulation. Subsequent imaging studies raised concerns regarding hemorrhagic stroke. A multidisciplinary team comprising cardiology, cardiothoracic surgery, infectious disease, and neurology collaborated to develop an optimal management strategy. Considering the high-risk features of the IE and the need to address the hemorrhagic stroke, anticoagulation was temporarily halted, and the patient was transferred for urgent mitral valve replacement surgery. This case highlights the complex interplay between substance abuse, cardiovascular complications, IE, and neurological events, underscoring the challenges encountered in managing such patients.

Epidemiologic and clinical characteristics of infective endocarditis: a single-center retrospective study in the Bronx, New York

OBJECTIVE

There is paucity of data on the epidemiological, microbiological, and clinical characteristics of patients admitted with infective endocarditis (IE) in the Bronx, New York.

PATIENT AND METHODS

We conducted a retrospective study at Jacobi Medical Center, a tertiary care hospital in the Bronx. All adult patients who were hospitalized with a primary diagnosis of new-onset IE between January 1st, 2010 and September 30th, 2020 were included. The primary outcome was in-hospital mortality. A logistic regression model was used to identify baseline variables associated with in-hospital mortality.

RESULTS

182 patients were included in this analysis (female sex: 38.5%, median age: 54 years). 46 patients (25.3%) reported intravenous drug use. 153 patients (84.1%) had positive blood cultures. Staphylococcus aureus (S. aureus) was the most common isolated pathogen (45.1% of monomicrobial IE). Nearly half of the cases secondary to S. aureus were methicillin resistant Staphylococcus aureus (MRSA) (34/69). 164 patients (90.1%) were diagnosed with native valve IE. The mitral valve was involved in 32.4% of patients followed by the aortic valve (19.8%). The in-hospital mortality was 18.1%. The mortality was higher in the cohort 2010-2015 compared to the cohort 2016-2020 (22.1% vs 14.6%). Increasing age, MRSA IE, and active malignancy were the only variables found to have significant association with in-hospital death.

CONCLUSION

S. aureus was the most common causative agent and MRSA accounted for about half of the S. aureus IE cases. The incidence of IE in patients with intravenous drug use increased over time, while the median age decreased. The in-hospital death rate was higher in 2010-2015 compared to 2016-2020.

APTC-C-SA01: A Novel Bacteriophage Cocktail Targeting Staphylococcus aureus and MRSA Biofilms

The high infection and mortality rate of methicillin-resistant Staphylococcus aureus (MRSA) necessitates the urgent development of new treatment strategies. Bacteriophages (phages) have several advantages compared to antibiotics for the treatment of multi-drug-resistant bacterial infections, and thus provide a promising alternative to antibiotics. Here, S. aureus phages were isolated from patients and environmental sources. Phages were characterized for stability, morphology and genomic sequence and their bactericidal activity against the biofilm form of methicillin-susceptible Staphylococcus aureus (MSSA) and MRSA was investigated. Four S. aureus phages were isolated and tested against 51 MSSA and MRSA clinical isolates and reference strains. The phages had a broad host range of 82−94% individually and of >98% when combined and could significantly reduce the viability of S. aureus biofilms. The phages had a latent period of ≤20 min and burst size of >11 plaque forming units (PFU)/infected cell. Transmission electron microscopy (TEM) identified phages belonging to the family of Myoviridae. Genomic sequencing indicated the lytic nature of all four phages, with no identified resistance or virulence genes. The 4 phages showed a high complementarity with 49/51 strains (96%) sensitive to at least 2/4 phages tested. Furthermore, the frequency of bacteriophage insensitive mutant (BIM) generation was lower when the phages were combined into the phage cocktail APTC-C-SA01 than for bacteria exposed to each of the phages alone. In conclusion, APTC-C-SA01, containing four lytic S. aureus phages has the potential for further development as a treatment against MSSA and MRSA infections.

No Correlation between Biofilm-Forming Capacity and Antibiotic Resistance in Environmental Staphylococcus spp.: In Vitro Results

The production of biofilms is a critical factor in facilitating the survival of Staphylococcus spp. in vivo and in protecting against various environmental noxa. The possible relationship between the antibiotic-resistant phenotype and biofilm-forming capacity has raised considerable interest. The purpose of the study was to assess the interdependence between biofilm-forming capacity and the antibiotic-resistant phenotype in 299 Staphylococcus spp. (S. aureus n = 143, non-aureus staphylococci [NAS] n = 156) of environmental origin. Antimicrobial susceptibility testing and detection of methicillin resistance (MR) was performed. The capacity of isolates to produce biofilms was assessed using Congo red agar (CRA) plates and a crystal violet microtiter-plate-based (CV-MTP) method. MR was identified in 46.9% of S. aureus and 53.8% of NAS isolates (p > 0.05), with resistance to most commonly used drugs being significantly higher in MR isolates compared to methicillin-susceptible isolates. Resistance rates were highest for clindamycin (57.9%), erythromycin (52.2%) and trimethoprim-sulfamethoxazole (51.1%), while susceptibility was retained for most last-resort drugs. Based on the CRA plates, biofilm was produced by 30.8% of S. aureus and 44.9% of NAS (p = 0.014), while based on the CV-MTP method, 51.7% of S. aureus and 62.8% of NAS were identified as strong biofilm producers, respectively (mean OD570 values: S. aureus: 0.779±0.471 vs. NAS: 1.053±0.551; p < 0.001). No significant differences in biofilm formation were observed based on MR (susceptible: 0.824 ± 0.325 vs. resistant: 0.896 ± 0.367; p = 0.101). However, pronounced differences in biofilm formation were identified based on rifampicin susceptibility (S: 0.784 ± 0.281 vs. R: 1.239 ± 0.286; p = 0.011). The mechanistic understanding of the mechanisms Staphylococcus spp. use to withstand harsh environmental and in vivo conditions is crucial to appropriately address the therapy and eradication of these pathogens.

Unreliability of Clinical Prediction Rules to Exclude without Echocardiography Infective Endocarditis in Staphylococcus aureus Bacteremia

BACKGROUND

It is unclear whether the use of clinical prediction rules is sufficient to rule out infective endocarditis (IE) in patients with Staphylococcus aureus bacteremia (SAB) without an echocardiogram evaluation, either transthoracic (TTE) and/or transesophageal (TEE). Our primary purpose was to test the usefulness of PREDICT, POSITIVE, and VIRSTA scores to rule out IE without echocardiography. Our secondary purpose was to evaluate whether not performing an echocardiogram evaluation is associated with higher mortality.

METHODS

We conducted a unicentric retrospective cohort including all patients with a first SAB episode from January 2015 to December 2020. IE was defined according to modified Duke criteria. We predefined threshold cutoff points to consider that IE was ruled out by means of the mentioned scores. To assess 30-day mortality, we used a multivariable regression model considering performing an echocardiogram as covariate.

RESULTS

Out of 404 patients, IE was diagnosed in 50 (12.4%). Prevalence of IE within patients with negative PREDICT, POSITIVE, and VIRSTA scores was: 3.6% (95% CI 0.1-6.9%), 4.9% (95% CI 2.2-7.7%), and 2.2% (95% CI 0.2-4.3%), respectively. Patients with negative VIRSTA and negative TTE had an IE prevalence of 0.9% (95% CI 0-2.8%). Performing an echocardiogram was independently associated with lower 30-day mortality (OR 0.24 95% CI 0.10-0.54, p = 0.001).

CONCLUSION

PREDICT and POSITIVE scores were not sufficient to rule out IE without TEE. In patients with negative VIRSTA score, it was doubtful if IE could be discarded with a negative TTE. Not performing an echocardiogram was associated with worse outcomes, which might be related to presence of occult IE. Further studies are needed to assess the usefulness of clinical prediction rules in avoiding echocardiographic evaluation in SAB patients.

Oxacillin plus ertapenem combination therapy leads to rapid blood culture clearance and positive outcomes among patients with persistent MSSA bacteraemia: a case series

Background

Bloodstream infections caused by MSSA are associated with significant morbidity and mortality. Traditional treatment of MSSA bacteraemia includes an IV antistaphylococcal β-lactam and surgical source control when indicated.

Objectives

To evaluate the time to blood culture clearance as well as in-hospital and 90 day mortality in patients with persistent MSSA bacteraemia treated with combination antistaphylococcal penicillin plus carbapenem therapy.

Methods

Consecutive patients with persistent MSSA bacteraemia treated with combination therapy were identified by study investigators and reviewed by independent clinicians. The decision to initiate combination therapy was made by the consulting clinician or by the institution’s multidisciplinary endocarditis team.

Results

Among 10 patients with a median of 5 days of persistent MSSA bacteraemia, treatment with an antistaphylococcal penicillin plus carbapenem led to sterilization of blood cultures in all patients. Blood culture clearance occurred in a median of 1 day and patients received a median of 6 days of combination treatment. Four of seven patients who underwent source control of their primary site of infection cleared their bacteraemia on combination therapy prior to the surgical intervention. All patients survived to hospital discharge and 90 days post-discharge.

Conclusions

These data extend prior findings and provide further evidence that suggests the potential benefits of combination therapy among patients with persistent MSSA bacteraemia.

Comparison of mortality, stroke, and relapse for methicillin-resistant versus methicillin-susceptible Staphylococcus aureus infective endocarditis: a retrospective cohort study

The purpose of this study was to compare survival, relapse, and stroke for patients with methicillin-resistant Staphylococcus aureus (MRSA) vs methicillin-susceptible S. aureus (MSSA) infective endocarditis (IE). In this retrospective study, the primary outcome of death and secondary outcomes of stroke and relapse were compared using multivariable Cox proportional hazards regression. Surgical treatment was adjusted for as a time-dependent variable. In total, 355 patients with at least one episode of IE caused by S. aureus were included. Patients with MRSA IE had higher mortality than those with MSSA IE (HR 1.34, 95% CI 1.01-1.77), but did not have a higher risk of stroke (HR 0.75, 95% CI 0.43-1.32) or relapse (HR 0.89, 95% CI 0.26-3.05). The cumulative incidence of relapse was very small. Among patients with IE caused by S. aureus MRSA infection is associated with higher mortality than MSSA infection.

[Evolution of antimicrobial resistance and mortality in Staphylococcus aureus endocarditis during 15 years in a university hospital]

OBJECTIVE

One of the most aggressive microorganisms in infective endocarditis (IE) is Staphylococcus aureus. We analyse the resistance of S. aureus to antibiotics and its impact on the clinical course of IE in a recent 15-year period.

METHODS

Retrospective study of patients with IE in a university hospital from 2005 to 2019. Bivariate and multivariate analysis of severity at admission, comorbidities, minimum inhibitory concentrations (MIC) and mortality.

RESULTS

Of the 293 IE cases, 66 (22.5%) were due to S. aureus, and 21 (7.2%) were methicillin-resistant S. aureus (MRSA). The prevalence of strains with a MIC to vancomycin ≥ 1mg/L increased from 4.8% to 63.6% (p <0.001) and the cases of MRSA from 38 to 27.3% (p = 0.045). Older age (p= 0.02), comorbidity (p <0.01) and nosohusial origin (p = 0.01), were factors associated with MRSA. But the antimicrobial resistance and severity on admission were not associated with exitus; predictive factors were the right-sided IE (OR = 0.08; 95% CI: 0.01-0.51), comorbidities (OR per Charlson index point = 1.30; 95% CI: 1.01-1.69) and creatinine on admission (OR per mg / dL = 1.56; 95% CI = 1.01- 2.35; p = 0.04).

CONCLUSIONS

We have experienced an increase in IE cases with MIC to vancomycin ≥ 1mg/L, without significant variation in infections due to MRSA. Antimicrobial resistance was not associated with mortality, but comorbidity and left involvement were predictive factors.

Staphylococcus aureus bacteremia and cardiac implantable electronic devices in a county hospital setting: a population-based retrospective cohort study

BACKGROUND

Due to a high incidence of cardiac implantable electronic device-associated infective endocarditis (CIED-IE) in cases of Staphylococcus aureus bacteremia (SAB) and high mortality with conservative management, guidelines advocate device removal in all subjects with SAB. We aimed to investigate the clinical course of SAB in patients with a CIED (SAB+CIED) in a Swedish county hospital setting and relate it to guideline recommendations.

METHODS

All CIED carriers with SAB, excluding clinical pocket infections, in the County of Västmanland during 2010-2017 were reviewed retrospectively.

RESULTS

There were 61 cases of SAB+CIED during the study period, and CIED-IE was diagnosed in 13/61 (21%) cases. In-hospital death occurred in 19/61 (31%) cases, 34/61 (56%) cases were discharged with CIED device retained, and 8/61 (13%) cases were discharged after device removal. Subjects dying during hospitalization were elderly and diseased. No events was seen if the CIED was removed. Among four discharged cases with conservatively managed CIED-IE one relapse occured. Among 30 cases discharged with retained CIED and no evidence of IE, 22/30 (73%) cases had an uneventful follow-up, whereas adverse events secondary to overlooked CIED-IE were likely in 1/30 (3%) cases and could not be definitely excluded in additionally 4/30 (13%) cases.

CONCLUSIONS

During the study period, management became more active and prognosis improved. The heterogeneity within the population of SAB+CIED suggests that a management strategy based on an individual risk/benefit analysis could be an alternative to mandatory device removal.

Risk Factors, Screening, and Treatment Challenges in Staphylococcus aureus Native Septic Arthritis

Background

Staphylococcus aureus is the most common cause of native septic arthritis. Few studies have characterized this disease during the US opioid epidemic. The role of methicillin-resistant Staphylococcus aureus (MRSA) nasal screening in this disease has not been elucidated. We sought to identify risk factors and outcomes for S. aureus native septic arthritis and to evaluate MRSA screening in this disease.

Methods

A retrospective cohort study of native septic arthritis patients (2012–2016) was performed. Demographics, risk factors, and outcomes were compared between Staphylococcus aureus and other native septic arthritis infections. Sensitivity, specificity, and predictive values of MRSA screening were assessed.

Results

Two hundred fifteen cases of native septic arthritis were included. S. aureus was cultured in 64% (138/215). MRSA was cultured in 23% (50/215). S. aureus was associated with injection drug use (odds ratio [OR], 4.33; 95% CI, 1.74–10.81; P = .002) and switching antibiotics (OR, 3.92; 95% CI, 1.01–21.38; P = .032). For every 10-year increase in age, the odds of S. aureus decreased (OR, 0.72; 95% CI, 0.60–0.87; P = .001). For 1-unit increases in Charlson comorbidity index score, the odds of S. aureus decreased (OR, 0.82; 95% CI, 0.73–0.91; P = .0004). MRSA screening during admission demonstrated a sensitivity of 0.59, specificity of 0.96, positive predictive value of 0.85, and negative predictive value of 0.84 for MRSA native septic arthritis.

Conclusions

The opioid epidemic may be contributing to a demographic shift in native septic arthritis to younger, healthier individuals. S. aureus native septic arthritis has unique risks, including injection drug use. MRSA screening may be useful to rule in MRSA native septic arthritis.