A successful salvage therapy with daptomycin and linezolid for right-sided infective endocarditis and septic pulmonary embolism caused by methicillin-resistant Staphylococcus aureus

Right-sided infective endocarditis or thrombus? Report of two cases diagnosed by transthoracic echocardiography

BACKGROUND

Right-sided infective endocarditis (RSIE) is a relatively uncommon condition which is difficult to distinguish from thrombus, particularly when the site of infection or the patient's symptoms are atypical. There have been few reports exploring the differential diagnostic and analytical features between RSIE and thrombus.

CASE PRESENTATION

Here, we presented two cases of RSIE-one involving the tricuspid valve and the other affecting the pulmonary artery. Notably, the second case was initially misdiagnosed as thrombus based on the findings of by computed tomography angiography(CTA).

CONCLUSIONS

Vegetation and thrombus can be distinguished according to the nature of the mass, its attachment location, and the clinical manifestation. Echocardiography can observe both the location and size of the mass, and the dynamic changes in cardiac hemodynamics and cardiac morphology, thereby facilitating an effective distinction between vegetation and thrombus.

Tricuspid Valve Endocarditis Due to Methicillin-Resistant Staphylococcus aureus in a Previously Healthy Young Patient without a Drug Abuse History: A Case Report and a Review of the Literature

Right-sided infective endocarditis due to methicillin-resistant Staphylococcus aureus (MRSA) is strongly associated with intravenous drug abuse, congenital heart disease, or previous medical treatment and is rare in healthy patients without a history of drug abuse. Here, we present a case of an 18-year-old male with no drug abuse history and no medical burden who was diagnosed with MRSA tricuspid valve endocarditis. Due to initial symptoms which indicated community-acquired pneumonia and radiological finding of interstitial lesions, empiric therapy with ceftriaxone and azithromycin was started. After the detection of Gram-positive cocci in clusters in several blood culture sets, endocarditis was suspected, and flucloxacillin was added to the initial therapy. As soon as methicillin resistance was detected, the treatment was switched to vancomycin. Transesophageal echocardiography established the diagnosis of right-sided infective endocarditis. A toxicological analysis of hair was carried out, and no presence of narcotic drugs was found. After six weeks of therapy, the patient was fully recovered. Exceptionally, tricuspid valve endocarditis can be diagnosed in previously healthy people who are not drug addicts. As the clinical presentation commonly resembles a respiratory infection, a misdiagnosis is possible. Although MRSA rarely causes community-acquired infections in Europe, clinicians should be aware of this possibility.

Comparison of valvuloplasty and replacement for surgical treatment of tricuspid infective endocarditis

BACKGROUND

Owing to the increase in both intravenous drug injections and intracardiac and vascular interventional treatments among drug users, the incidence of infective endocarditis (IE) involving the tricuspid valve, which sits between the two right heart chambers, has gradually increased. This study aimed to compare the clinical outcomes of different surgical procedures for tricuspid infective endocarditis (TIE).

METHODS

We retrospectively analyzed fifty-six patients who underwent tricuspid valve surgery at our hospital from January 2006 to August 2019. All patients were diagnosed with TIE and indicated a need for surgery. Perioperative and follow-up data were collected to summarize and analyze the clinical outcomes of different surgical approaches, including tricuspid valvuloplasty (TVP) and tricuspid valve replacement (TVR) for TIE.

RESULTS

Cardiopulmonary bypass (CPB) time, aortic cross-clamp (ACC) time, postoperative mechanical ventilation time, and intensive care unit (ICU) stay time were shorter in the TVP group than in the TVR group. Additionally, the incidence of red blood cell transfusion and postoperative complications was lower in the TVP group than in the TVR group. The postoperative 30-day mortality rates were similar between both the groups. Fifty-two patients were followed up for an average of 5.50 ± 3.79 years. The postoperative 3-, 5-, and 7-year survival rates were 100%, 100%, and 95.5% in the TVP group and 96.7%, 96.7%, and 96.7% in the TVR group, respectively. The 5-year and 10-year reoperation rates were 0% and 0% in the TVP group and 6.7% and 20% in the TVR group, respectively.

CONCLUSION

Both TVR and TVP for TIE significantly improved the functional status of the heart with satisfactory efficacy. TVP was found to be superior to TVR in reducing the need for postoperative blood transfusions, reducing the risk of postoperative complications, and reducing the need for long-term reoperations.

Daptomycin and linezolid for severe methicillin-resistant Staphylococcus aureus psoas abscess and bacteremia: A case report and review of the literature

BACKGROUND

Vancomycin remains a first-line treatment drug as per the treatment guidelines for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. However, a number of gram-positive cocci have developed resistance to several drugs, including glycopeptides. Therefore, there is an urgent need for effective and innovative antibacterial drugs to treat patients with infections caused by drug-resistant bacteria.

CASE SUMMARY

A 24-year-old male was admitted to hospital owing to lumbago, fever, and hematuria. Computed tomography (CT) results showed an abscess in the psoas major muscle of the patient. Repeated abscess drainage and blood culture suggested MRSA, and vancomycin was initiated. However, after day 10, CT scans showed abscesses in the lungs and legs of the patient. Therefore, treatment was switched to daptomycin. Linezolid was also added considering inflammation in the lungs. After 10 d of the dual-drug anti-MRSA treatment, culture of the abscess drainage turned negative for MRSA. On day 28, the patient was discharged without any complications.

CONCLUSION

This case indicates that daptomycin combined with linezolid is an effective remedy for bacteremia caused by MRSA with pulmonary complications.

Vascular Complications of Infective Endocarditis: Diagnosis and Management

Introduction: The complications of infective endocarditis (IE) are frequent and severe. Our aim was to study the clinical and paraclinical profiles and prognosis of vascular complications, observed in a cardiology unit in Oujda, Morocco. Among 57 patients hospitalized for IE between 2015 and 2020 at the cardiology unit, 19 patients, or 33.3% of patients, had one or more vascular complications. We present here a retrospective analysis.

Aim: Prevention, early diagnosis, and treatment of vascular complications are primordial to improving prognosis, following the guidelines of the European Society of Cardiology.

Patients and methods: We retrospectively studied 57 patients hospitalized for IE. The diagnostic criteria for IE were modified from the Duke University criteria and we present all vascular complications among this cohort.

Results: Nineteen patients presented with one or more vascular complications, 10 men and nine women, with a mean age of 49 years. IE had grafted on a mechanical prosthetic valve in four cases. Overall, we found 25 vascular lesions: six neurological complications, five cases of peripheral vascular involvement, nine splenic infarcts, and five recurrent septic pulmonary embolisms (SPEs). The vascular complications accrued after three to 14 days of antibiotherapy or on extension reports; blood cultures were positive in 17 (89.4%) cases; streptococcus was isolated in nine cases; Staphylococcus aureus in seven cases; and acinetobacter in one case.

Conclusion: Vascular complications of IE are severe, the most common in our study being splenic infarct. Prevention and early diagnosis are essential to instituting optimal management.

All the patients were followed up with a mean follow-up of three years. Late mortality involved one patient in connection with a hemorrhagic stroke secondary to an accident with vitamin K antagonists after its release in one month. No cases of recurrence of endocarditis were noted in this group.

Data were collected from archived medical records and analyzed by Statistical Package for the Social Sciences.

Comparison of the Clinico-Microbiological Characteristics of Culture-Positive and Culture-Negative Septic Pulmonary Embolism: A 10-Year Retrospective Study

Septic pulmonary embolism (SPE) is a rare yet serious infectious disorder with nonspecific clinical findings due to microorganism-containing emboli disseminating from extrapulmonary infectious foci. It is unknown whether a positive blood culture correlates with a worse clinical outcome. We compared the clinical and microbiologic characteristics of patients with SPE divided into the culture-positive group and the culture-negative one. This study was a retrospective observational study of the patients diagnosed with SPE and treated in an academic hospital from April 2010 to May 2020. We identified six culture-positive and four culture-negative patients with SPE during the study period. The culture-positive group had significantly longer periods of hospitalization (median: 75 days, range: 45-125 days) than the culture-negative group (median: 14.5 days, range: 3-43 days) (p < 0.05), as well as significantly elevated serum C-reactive protein and procalcitonin. Patients with culture-negative SPE more commonly had odontogenic infections as the primary infectious foci. Our study highlights the importance of giving extra attention to SPE patients who have a positive blood culture, as they may have worse clinical outcomes. Physicians need to collaborate with dentists when faced with patients with culture-negative SPE, since they may have primary odontogenic infections.

The Evolving Reduction of Vancomycin and Daptomycin Susceptibility in MRSA-Salvaging the Gold Standards with Combination Therapy

Methicillin-resistant Staphylococcus aureus (MRSA) is associated with substantial morbidity and mortality. Vancomycin (VAN) has been used as the gold standard treatment for invasive MRSA infections for decades but, unfortunately, the reliance of VAN as the primary treatment option against these infections has led to a reduction in VAN susceptibility in MRSA isolates. Although daptomycin (DAP) is another common treatment option against invasive MRSA infections, it has been shown that the development of VAN resistance can lead to DAP nonsusceptibility. VAN or DAP backbone regimens in combination with other antibiotics has been advocated as an alternative approach to improve patient outcomes in VAN/DAP-susceptible infections, enhance outcomes in infections caused by isolates with reduced VAN/DAP susceptibility, and/or prevent the emergence of VAN/DAP resistance or further resistance. A peer-reviewed literature search was conducted using Medline, Google Scholar and PubMed databases. The primary purpose of this review is to describe the mechanisms and epidemiology of MRSA isolates with a reduction in VAN and/or DAP susceptibility, evaluate in vitro and in vivo literature describing combination therapy (CT) against MRSA isolates with reduced VAN and/or DAP susceptibility and describe studies involving the clinical outcomes of patients treated with CT against invasive MRSA infections.

Treatment of tricuspid valve endocarditis with daptomycin and linezolid therapy

Purpose

A case report of the use of linezolid and daptomycin for the treatment of multidrug-resistant right-sided infective endocarditis is presented.

Summary

A 36-year-old patient with a history of intravenous drug use was hospitalized for treatment of native tricuspid valve endocarditis resulting in persistent methicillin-resistant Staphylococcus aureus bacteremia. During the admission the patient was unsuccessfully treated with vancomycin monotherapy (final E-test minimum inhibitory concentration, 4 μg/mL). The patient’s treatment was switched to daptomycin and gentamicin, with no improvement in blood culture results over 4 days. Gentamicin was discontinued, and linezolid was administered in combination with daptomycin; bacteremia was cleared after 13 days of linezolid and daptomycin combination therapy. Due to daptomycin resistance (minimum inhibitory concentration, 4 μg/mL), gentamicin was substituted for daptomycin due to the former agent’s synergistic effects with linezolid. After 23 days of therapy the patient was transferred to another facility for a tricuspid valve replacement procedure, which was completed without complications. The patient was transferred in stable condition to a skilled nursing facility to continue antibiotic therapy lasting 6 weeks from the date of surgery. The patient’s blood cultures remained negative.

Conclusion

A 36-year-old woman with resistant tricuspid valve endocarditis was successfully treated with linezolid in combination with daptomycin.

Treatments and limitations for methicillin-resistant Staphylococcus aureus: A review of current literature

Methicillin-resistant Staphylococcus aureus (MRSA) has remained a major threat to healthcare; in both hospital and community settings over the past five decades. With the current use of antibiotics for a variety of infections, including MRSA, emerging resistance is a major concern. Currently available treatments have restrictions limiting their use. These issues include, but are not limited to, side effects, cross-resistance, lack of understanding of pharmacokinetics and clinical pharmacodynamics, gradual increment in minimal inhibitory concentration over the period (MIC creep) and ineffectiveness in dealing with bacterial biofilms. Despite availability of various therapeutic options for MRSA, the clinical cure rates remain low with high morbidity and mortality. Given these challenges with existing treatments, there is a need for development of novel agents for MRSA. Along with prompt infection control strategies and strict implementation of antibiotic stewardship, cautious use of newer anti-MRSA agents will be of utmost importance. This article reviews the treatments and limitations of MRSA management and highlights the future path.