Practical Guidance for Clinical Microbiology Laboratories: Microbiologic diagnosis of implant-associated infections.

SUMMARYImplant-associated infections (IAIs) pose serious threats to patients and can be associated with significant morbidity and mortality. These infections may be difficult to diagnose due, in part, to biofilm formation on device surfaces, and because even when microbes are found, their clinical significance may be unclear. Despite recent advances in laboratory testing, IAIs remain a diagnostic challenge. From a therapeutic standpoint, many IAIs currently require device removal and prolonged courses of antimicrobial therapy to effect a cure. Therefore, making an accurate diagnosis, defining both the presence of infection and the involved microorganisms, is paramount. The sensitivity of standard microbial culture for IAI diagnosis varies depending on the type of IAI, the specimen analyzed, and the culture technique(s) used. Although IAI-specific culture-based diagnostics have been described, the challenge of culture-negative IAIs remains. Given this, molecular assays, including both nucleic acid amplification tests and next-generation sequencing-based assays, have been used. In this review, an overview of these challenging infections is presented, as well as an approach to their diagnosis from a microbiologic perspective.

Beyond the Timeline: One-year Mortality Trends in Early vs. Late Prosthetic Valve Endocarditis.

Among 302 episodes with prosthetic valve endocarditis (PVE), one-year mortality was 31%. There was no evidence indicating that early-onset PVE within 6 months from valve surgery led to a worse outcome compared to late-onset PVE (21% versus 32%; p=0.126), despite similar redo valve surgeries across both categories.

Cutibacterium Species Valvular and Cardiac Device-Related Infective Endocarditis: Contemporary Data From the GAMES Prospective Cohort (2008-2023).

BACKGROUND: Information on infective endocarditis (IE) caused by Cutibacterium spp. is limited and new Duke-International Society for Cardiovascular Infectious Diseases (ISCVID) criteria have not yet been properly assessed. We examined clinical characteristics, outcomes, and performance of diagnostic tests for Cutibacterium valvular and cardiac implantable electronic device-related IE (CIED-IE). METHODS: Data corresponding to all episodes of Cutibacterium IE recorded from 2008 to 2023 in a prospective national cohort including 46 Spanish hospitals were examined. Possible IE cases were reassessed using the new criteria. The sensitivity of blood cultures, valvular and CIED cultures, and polymerase chain reaction of the 16S rRNA gene and sequencing (16SPCR) was evaluated. RESULTS: Of 6692 episodes of IE, 67 (1%) were caused by Cutibacterium spp. with 85% affecting men. Of these, 50 were valve-related (45 prosthetic, 5 native) and 17 CIED-related. The new criteria identified 8 additional cases and reclassified 15 as definite IE. Intracardiac complications (abscess, pseudoaneurysm, perforation, or intracardiac fistula) occurred in 23 of 50 (46%) valvular IE episodes, leading to 18% mortality, and up to 40% mortality if surgery was indicated but could not be performed. All CIED-IE cases underwent device removal and no deaths were recorded. Positive diagnosis rates for blood cultures, valve/device cultures, and 16SPCR were 52%, 70%, and 82%, respectively. CONCLUSIONS: Cutibacterium IE is a rare yet potentially life-threatening condition that warrants a high index of suspicion in men with endovascular prosthetic material. The new Duke-ISCVID criteria and molecular techniques are useful for its diagnosis. Considering a significant complication rate, cardiac surgery and removal of CIEDs play a key role in reducing mortality.

Prosthetic Valve Endocarditis Caused by Pasteurella dagmatis, Germany.

An 81-year-old male patient in Germany had prosthetic valve endocarditis caused by Pasteurella dagmatis after a domestic cat bite. We surgically treated a paravalvular abscess and administered definitive antibiotic therapy consisting of penicillin G and levofloxacin. The patient was discharged from the intensive care unit in good condition 21 days after the surgery.

Prosthetic Valve Endocarditis After Aortic Valve Replacement: Differences Between Biological and Mechanical Prostheses.

AIMS: Prosthetic valve endocarditis (PVE) is the most severe form of infective endocarditis associated with a high mortality rate. Whether PVE affects biological and mechanical aortic valves to the same extent remains controversial. This study aimed to compare the incidence of re-intervention because of PVE between bioprosthetic and mechanical valves. METHODS: Patients undergoing isolated surgical aortic valve replacement (AVR) or combined AVR in a single cardiac surgery centre between January 1998 and December 2019 were analysed. All patients who underwent re-intervention because of PVE were identified. The primary endpoint was the rate of explants. Freedom from re-intervention and variables associated with re-intervention were analysed using Cox regression analysis including correction for competing risk. RESULTS: During the study period, 5,983 aortic valve prostheses were implanted, including 3,620 biological (60.5%) and 2,363 mechanical (39.5%) prostheses. The overall mean follow-up period was 7.3±5.3 years (median, 6.5; IQR 2.9-11.2 years). The rate of re-intervention for PVE in the biological group was 1.5% (n=54) compared with 1.7% (n=40) in the mechanical group (p=0.541). Cox regression analysis revealed that younger age (HR 0.960, 95% CI 0.942-0.979; p<0.001), male sex (HR 2.362, 95% CI 1.384-4.033; p=0.002), higher creatinine (HR 1.002, 95% CI 0.999-1.004; p=0.057), and biological valve prosthesis (HR 2.073, 95% CI 1.258-3.414; p=0.004) were associated with re-intervention for PVE. After correction for competing risk of death, biological valve prosthesis was significantly associated with a higher rate of re-intervention for PVE (HR 2.011, 95% CI 1.177-3.437; p=0.011). CONCLUSIONS: According to this single-centre, observational, retrospective cohort study, AVR using biological prosthesis is associated with re-intervention for PVE compared to mechanical prosthesis. Further investigations are needed to verify these findings.

New Perspectives for Prosthetic Valve Endocarditis: Impact of Molecular Imaging by FISHseq Diagnostics.

BACKGROUND: The microbial etiology of prosthetic valve infective endocarditis (PVE) can be difficult to identify. Our aim was to investigate the benefit of molecular imaging technique fluorescence in situ hybridization (FISH) combined with 16S rRNA-gene polymerase chain reaction (PCR) and sequencing (FISHseq) for the analysis of infected prosthetic heart valves. METHODS: We retrospectively evaluated the diagnostic outcome of 113 prosthetic valves from 105 patients with suspected PVE, treated in 2003-2013 in the Department of Cardiac Surgery, Charité University Medicine Berlin. Each prosthetic valve underwent cultural diagnostics and was routinely examined by FISH combined with 16S rRNA gene PCR and sequencing. We compared classical microbiological culture outcomes (blood and valve cultures) with FISHseq results and evaluated the diagnostic impact of the molecular imaging technique. RESULTS: Conventional microbiological diagnostic alone turned out to be insufficient, as 67% of preoperative blood cultures were noninformative (negative, inconclusive, or not obtained) and 67% of valve cultures remained negative. FISHseq improved the conventional cultural diagnostic methods in PVE in 30% of the cases and increased diagnostic accuracy. Of the valve culture-negative PVE cases, FISHseq succeeded in identifying the causative pathogen in 35%. CONCLUSIONS: FISHseq improves PVE diagnostics, complementing conventional cultural methods. In addition to species identification, FISH provides information about the severity of PVE and state of the pathogens (eg, stage of biofilm formation, activity, and localization on and within the prosthetic material). As a molecular imaging technique, FISHseq enables the unambiguous discrimination of skin flora as contaminant or infectious agent.

Prognosis and follow-up of patients with prosthetic valve endocarditis treated conservatively in relation to WBC-SPECT imaging.

BACKGROUND: Our objective was to evaluate in patients with prosthetic valve endocarditis (PVE) treated conservatively, the prognostic value of white blood cell (WBC) signal intensity on SPECT and to describe the evolution of the WBC signal under antibiotics. METHODS: Patients with PVE treated conservatively and positive WBC-SPECT imaging were identified retrospectively. Signal intensity was classified as intense if equal to or higher, or mild if lower, than the liver signal. Clinical, biological, imaging and follow-up information were collected from medical files. RESULTS: Among 47 patients, WBC signal was classified as intense in 10 patients and as mild, in 37. The incidence of the primary composite endpoint (death, late cardiac surgery, or relapse) was significantly higher in patients with intense vs. mild signal (90% vs. 11%). Twenty-five patients underwent a second WBC-SPECT imaging during follow-up. The prevalence of WBC signal decreased progressively from 89% between 3 and 6 weeks to 42% between 6 and 9 weeks and 8% more than 9 weeks after initiation of antibiotics. CONCLUSIONS: In patients with PVE treated conservatively, intense WBC signal was associated with poor outcome. WBC-SPECT imaging appears as an interesting tool for risk stratification and to monitor locally the efficacy of antibiotic treatment.

A rare complication of double prosthetic valve endocarditis; reconstructive surgical treatment of mitral-aortic intervalvular fibrosa pseudoaneurysm and left atrial fistula.

Mitral aortic intervalvular fibrosa or aorto-mitral curtain is a fibrous avascular skeletal structure located between the anterior leaflet of the mitral valve and the non-coronary and left coronary cusps of the aortic valve. Mitral and aortic valve endocarditis are rarely accompanied by mitral aortic intervalvular fibrosa pseudoaneurysm and left atrial fistula of the aorta. Pseudoaneurysm of mitral aortic intervalvular fibrosa is a fatal complication that can occur after valvular surgery, valvular endocarditis, or blunt trauma. In this article, reconstructive surgical management with the Commando technique of a case who developed mitral-aortic intervalvular fibrosa pseudoaneurysm to left atrial fistula after aortic and mitral prosthetic valve endocarditis is described. The important feature of this article is that it is a first in the literature as it is accompanied by persistent left superior vena cava.

Challenges in cardiology: diagnosis of native and prosthetic valve endocarditis.

New cardiovascular imaging technologies have strongly influenced the diagnosis of bacterial endocarditis [infective endocarditis (IE)]. The clinical presentation of IE is polymorphic, which explains the difficulty of diagnosis and the delay in treatment. Symptoms such as fever, chills, loss of appetite and weight, and embolic phenomena strongly support the diagnosis of endocarditis, but are not always present, particularly in elderly or immuno-compromised patients. Moreover, subtle symptoms in patients at high risk for the development of IE, such as those with prosthetic valves or intracardiac devices, patients with congenital heart disease, and drug addicts should lead to the suspicion that a diagnosis of IE is highly probable. In this review, we will focus on the diagnosis of complex IE in native valves and prosthetic valves.

Twenty-Year Experience with Surgery for Native and Prosthetic Mitral Valve Endocarditis.

Background and Objectives: To evaluate the early and long-term results of surgical treatment of isolated mitral native and prosthetic valve infective endocarditis. Materials and Methods: All patients undergoing mitral valve repair or replacement for infective endocarditis at our institution between January 2001 and December 2021 were included in the study. The preoperative and postoperative characteristics and mortality of patients were retrospectively reviewed. Results: A total of 130 patients, 85 males and 45 females, with a median age of 61 ± 14 years, underwent surgery for isolated mitral valve endocarditis during the study period. There were 111 (85%) native and 19 (15%) prosthetic valve endocarditis cases. Fifty-one (39%) patients died during the follow-up, and the overall mean patient survival time was 11.8 ± 0.9 years. The mean survival time was better in patients with mitral native valve endocarditis compared to patients with prosthetic valve endocarditis (12.3 ± 0.9 years vs. 8 ± 1.4 years; p = 0.1), but the difference was not statistically significant. Patients who underwent mitral valve repair had a better survival rate compared to patients who had mitral valve replacement (14.8 ± 1.6 vs. 11.3 ± 1 years; p = 0.06); however, the difference was not statistically significant. Patients who underwent mitral valve replacement with a mechanical prosthesis had a significantly better survival rate compared to patients who received a biological prosthesis (15.6 ± 1.6 vs. 8.2 ± 0.8 years; p < 0.001). Patients aged ≤60 years had significantly better survival compared to patients aged >60 years (17.1 ± 1.1 vs. 8.2 ± 0.9; p < 0.001). Multivariate analysis showed that the patient's age >60 years at the time of surgery was an independent risk factor for mortality, while mitral valve repair was a protective factor. Eight (7%) patients required reintervention. Freedom from reintervention was significantly higher in patients with mitral native valve endocarditis compared to patients with prosthetic valve endocarditis (19.3 ± 0.5 vs. 11.5 ± 1.7 years; p = 0.04). Conclusions: Surgery for mitral valve endocarditis is associated with considerable morbidity and mortality. The patient's age at the time of surgery represents an independent risk factor for mortality. Mitral valve repair should be the preferred choice whenever possible in suitable patients affected by infective endocarditis.

Minimally Invasive Surgery: Standard of Care for Mitral Valve Endocarditis.

Background. Minimally invasive surgery via right mini-thoracotomy has become the standard of care for the treatment of mitral valve disease worldwide, particularly at high-volume centers. In recent years, the spectrum of indications has progressively shifted and extended to fragile and higher-risk patients, also addressing more complex mitral valve disease and ultimately including patients with native or prosthetic infective endocarditis. The rationale for the adoption of the minimally invasive approach is to minimize surgical trauma, promote an earlier postoperative recovery, and reduce the incidence of surgical wound infection and other nosocomial infections. The aim of this retrospective observational study is to evaluate the effectiveness and the early and late outcome in patients undergoing minimally invasive surgery for mitral valve infective endocarditis. Methods. Prospectively collected data regarding minimally invasive surgery in patients with mitral valve infective endocarditis were entered into a dedicated database for the period between January 2007 and December 2022 and retrospectively analyzed. All comers during the study period underwent a preoperative evaluation based on their clinical history and anatomy for the allocation to the most appropriate surgical strategy. The selection of the mini-thoracotomy approach was primarily driven by a thorough transthoracic and especially transesophageal echocardiographic evaluation, coupled with total body and vascular imaging. Results. During the study period, 92 patients underwent right mini-thoracotomy to treat native (80/92, 87%) or prosthetic (12/92, 13%) mitral valve endocarditis at our institution, representing 5% of the patients undergoing minimally invasive mitral surgery. Twenty-six (28%) patients had undergone previous cardiac operations, whereas 18 (20%) presented preoperatively with complications related to endocarditis, most commonly systemic embolization. Sixty-nine and twenty-three patients, respectively, underwent early surgery (75%) or were operated on after the completion of the targeted antibiotic treatment (25%). A conservative procedure was feasible in 16/80 (20%) patients with native valve endocarditis. Conversion to standard sternotomy was necessary in a single case (1.1%). No cases of intraoperative iatrogenic aortic dissection were reported. Four patients died perioperatively, accounting for a thirty-day mortality of 4.4%. The causes of death were refractory heart or multiorgan failure and/or septic shock. A new onset stroke was observed postoperatively in one case (1.1%). Overall actuarial survival rate at 1 and 5 years after operation was 90.8% and 80.4%, whereas freedom from mitral valve reoperation at 1 and 5 years was 96.3% and 93.2%, respectively. Conclusions. This present study shows good early and long-term results in higher-risk patients undergoing minimally invasive surgery for mitral valve infective endocarditis. Total body, vascular, and echocardiographic screening represent the key points to select the optimal approach and allow for the extension of indications for minimally invasive surgery to sicker patients, including active endocarditis and sepsis.

Microbiological etiology in prosthetic valve endocarditis: A nationwide registry study.

BACKGROUND: Prosthetic valve endocarditis (PVE) is a feared complication after heart valve surgery. Studies on differences in bacteriology in various types of PVE are limited. OBJECTIVES: This study aimed to investigate the microbiology of PVE depending on the type of prosthetic valve and timing of diagnosis. METHODS: A retrospective study based on the Swedish Registry on Infective Endocarditis focusing on PVE was conducted. The cohort was divided into mechanical and bioprosthetic valves; into endocarditis localization in the aortic, mitral, or tricuspid valve; and into early and late PVE. The microbiology in these groups was compared. Predictors of Staphylococcus aureus as the cause of PVE were examined by multivariable logistic regression. RESULTS: A total of 780 episodes of PVE in 749 patients were compared regarding the distribution of causative microbiological agents. The most common agents included alpha-hemolytic streptococci (29%), S. aureus (22%), enterococci (14%), coagulase-negative staphylococci (CoNS) (12%), and Cutibacterium acnes (6%). S. aureus was more commonly found on mechanical valves compared to bioprosthetic ones (36% vs. 17%, p < 0.001) whereas alpha-hemolytic streptococci, enterococci, and CoNS were more common on bioprosthetic valves. There were no significant differences in the microbiology of PVE affecting mitral or aortic valves or in cases of early and late PVE. Predictors for S. aureus as the cause of PVE were end-stage renal disease, intravenous drug use, mechanical valve, and tricuspid localization of endocarditis. CONCLUSIONS: The type of prosthetic heart valve is associated with the causative pathogen. Patients with mechanical valves are more likely to have PVE caused by S. aureus.

Diagnostic performance of White Blood Cell SPECT imaging against intra-operative findings in patients with a suspicion of prosthetic valve endocarditis.

AIM: The objective of this study was to evaluate the diagnostic performance of white blood cells (WBC)-SPECT imaging in patients with suspicion of prosthetic valve endocarditis (PVE) against intra-operative findings. METHODS: 36 consecutive patients who underwent cardiac surgery 30 days after WBC-SPECT imaging were identified retrospectively. Clinical, imaging, and biological results were collected from reports. WBC-SPECT results were classified as positive or negative and, if positive, the intensity of signal graded as intense or mild. Lesions observed during cardiac surgery were collected from surgeons' reports. RESULTS: The 20 patients with positive WBC-SPECT study had confirmed PVE intra-operatively. Patients with intense signal on WBC-SPECT had high prevalence of abscesses (83%) compared to patients with only mild signal (12%). The three patients with negative WBC-SPECT but confirmed PVE had longer duration of antibiotic treatment before imaging and had no perivalvular abscess. Sensitivity, specificity, positive predictive and negative values, and accuracy of WBC-SPECT were measured at 87%, 100%, 100%, 81%, and 92%, respectively. Addition of WBC-SPECT results to the modified Duke score helped re-classify correctly 25% of patients from possible to definite PVE. CONCLUSION: In patients with suspicion of PVE, WBC-SPECT imaging provides excellent diagnostic performance against intra-operative findings.

Temporal Trends, Characteristics, and Outcomes of Infective Endocarditis After Transcatheter Aortic Valve Replacement.

BACKGROUND: Procedural improvements combined with the contemporary clinical profile of patients undergoing transcatheter aortic valve replacement (TAVR) may have influenced the incidence and outcomes of infective endocarditis (IE) following TAVR. We aimed to determine the temporal trends, characteristics, and outcomes of IE post-TAVR. METHODS: Observational study including 552 patients presenting definite IE post-TAVR. Patients were divided in 2 groups according to the timing of TAVR (historical cohort [HC]: before 2014; contemporary cohort [CC]: after 2014). RESULTS: Overall incidence rates of IE were similar in both cohorts (CC vs HC: 5.45 vs 6.52 per 1000 person-years; P = .12), but the rate of early IE was lower in the CC (2.29‰ vs 4.89‰, P < .001). Enterococci were the most frequent microorganism. Most patients presented complicated IE ( CC: 67.7%; HC: 69.6%; P = .66), but the rate of surgical treatment remained low (CC: 20.7%; HC: 17.3%; P = .32). The CC exhibited lower rates of in-hospital acute kidney injury (35.1% vs 44.6%; P = .036) and in-hospital (26.6% vs 36.4%; P = .016) and 1-year (37.8% vs 53.5%; P < .001) mortality. Higher logistic EuroScore, Staphylococcus aureus etiology, and complications (stroke, heart failure, and acute renal failure) were associated with in-hospital mortality in multivariable analyses (P < .05 for all). CONCLUSIONS: Although overall IE incidence has remained stable, the incidence of early IE has declined in recent years. The microorganism, high rate of complications, and very low rate of surgical treatment remained similar. In-hospital and 1-year mortality rates were high but progressively decreased over time.

A modified technique for aortic prosthesis implantation after prosthetic valve endocarditis complicated by complex paraannular aortic abscess.

The aim of this study is to describe a modified technique for aortic prosthesis implantation in the sinuses of Valsalva without the use of a patch for aortic annular reconstruction in patients with prosthetic valve endocarditis complicated by aortic abscess. From January 2008 to March 2021, 47 patients underwent aortic valve replacement due to prosthetic aortic valve endocarditis. The new aortic prosthesis was implanted into the sinuses of Valsalva above the abscess left open to drain. The first step consists in passing U-shaped stitches with pledgets through the aortic wall approximately 5-7 mm above the abscess involving the annulus. In the second step, the prosthesis is fixed to the aortic wall. In the third step, a 10 mm wide Teflon strip is positioned along the external course of the aortic wall and U-shaped stitches without pledgets are passed from the outside to the inside to definitively fix the prosthetic annulus to the sinuses of Valsalva. In-hospital mortality was 8.5% (4/47 patients). Mean follow-up was 62 ± 37.7 months. Four patients died (9.3%). Predicted probability of cardiac vs non-cardiac mortality was not statistically significant (p = 0.88). Overall survival probability (freedom from all-cause death) at 3, 7 and 9 years was 97%, 87.5% and 75%, respectively. No patients presented with grade 2 or 3 peri-prosthetic leak, nor had endocarditis. Prosthetic valve endocarditis complicated by complex paraannular aortic abscess can be successfully addressed with good long-term results by using our alternative technique.

Transcatheter aortic valve replacement associated infective endocarditis case series: broadening the criteria for diagnosis is the need of the hour.

BACKGROUND: Transcatheter valve replacement (TAVR) is an important therapeutic intervention for patients with aortic valve stenosis. As TAVR has become available to a broader population, there has been an increase in the number of less common, yet potentially catastrophic, complications. TAVR related infective endocarditis (TAVR-IE) is a rare, but potentially fatal, complication. CASE SERIES: We present here two patients that we encountered for TAVR associated infective endocarditis. Our first patient presented 5 weeks after his TAVR. His initial presentation was consistent with signs of sepsis. The patient then developed Mobitz type I block during hospital course. His TEE was negative for features of infective endocarditis. Due to high suspicion, patient was taken for surgical exploration and was found to have multiple foci of vegetation adhered to the stent frame. Our second patient presented with new onset pulmonary edema, worsening heart failure and systemic inflammatory response. A TEE was done for persistent MSSA bacteremia which showed stable prosthetic valve function with no signs of infective endocarditis. Patient was discharged with a prolonged course of intravenous antibiotics. Patient was re-admitted for worsening sepsis and blood cultures were positive for MSSA. Patient was taken for surgical exploration of his prosthetic aortic valve which showed purulent aortic root abscess. CONCLUSION: Through these cases, we aim to raise awareness on TAVR-IE. Due to the atypical clinical presentation, the modified Duke criteria may not be sufficient to diagnose TAVR-IE. Transesophageal echocardiogram in TAVR-IE may be negative or indeterminate. Prosthetic valve shadow may obscure smaller vegetations and/or smaller abscesses. A negative transesophageal echocardiogram should not rule out TAVR-IE and further diagnostic imaging modalities should be considered. PET/CT after administration of 18F-FDG (fluorodeoxyglucose) is a useful diagnostic tool in the diagnosis of infective endocarditis where TEE has been negative or inconclusive. Multi-modal imaging, in addition to the modified Duke criteria, can facilitate early diagnosis and improved mortality outcomes.

A case series of medically managed Candida parapsilosis complex prosthetic valve endocarditis.

BACKGROUND: In recent years, Candida parapsilosis is recognized as a species complex and is composed of Candida parapsilosis sensu stricto, Candida orthopsilosis and Candida metapsilosis. Candida parapsilosis complex prosthetic valve endocarditis (PVE) is rare and the survival rate is still low despite of optimal therapeutic strategies. In our report, it is novel to report cases as Candida parapsilosis complex PVE at species and identify Candida parapsilosis using MALDI-TOF MS. Case presentation A series of 4 cases of Candida parapsilosis complex PVE from our institution was reported. Three were infected by Candida parapsilosis sensu stricto and one was infected by Candida metapsilosis. The condition of two cases got better and the other died. CONCLUSIONS: More attention should be paid to Candida parapsilosis complex PVE and early diagnosis and prompt antibiotic therapy may play a role in the treatment for Candida parapsilosis complex PVE. It is recommended to identify Candida parapsilosis complex at species level and MALDI-TOF MS as an easy, fast and efficient identification method is worth promoting in clinical microbiology.

First case report of prosthetic valve endocarditis caused by Mycobacterium wolinskyi.

To date, only 26 cases of Mycobacterium wolinskyi infections have been reported in humans. We herein report a first case of prosthetic valve endocarditis due to this organism after cardiovascular surgery. An 82-year-old man presented with repeat episodes of syncope and fever after aortic valve replacement, mitral valve replacement, left atrial appendage closure, and pulmonary vein isolation. Blood cultures maintained in aerobic bottles were repeatedly positive after 90-100 hours, and Gallium scan revealed abnormal accumulations in the sternum and left testis. While colonies formed by culturing the fluid of the parasternal area and blood cultures revealed gram-positive rods, we could not analyze the colony using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF). M. wolinskyi was finally identified on 16S rRNA, hsp65, and rpoB gene sequencing. We treated the patient with multiple antimycobacterial drugs, i.e., amikacin, imipenem, and clarithromycin for 6 weeks, which was changed to oral ciprofloxacin and minocycline for 12 months. This case highlights the need to consider rapidly growing mycobacteria, including M. wolinskyi, if chronic fever persists from weeks to months after surgery, the blood culture is positive, and the organism is not identified. In addition, sequencing the 16S rRNA, hsp65, and rpoB genes is essential for diagnosis.

Clinical Outcome of Reoperation for Mechanical Prosthesis at Aortic Position.

AIM: Redo aortic valve surgery is usually associated with a high risk of mortality and complications. The aim of this study was to investigate the perioperative and long-term outcomes of reoperation after prior mechanical prosthesis implantation at the aortic position. METHOD: The clinical data of 146 consecutive patients who underwent reoperation at the aortic position between 2003 and 2019 were analysed. RESULTS: Mean age was 51.5±12.7 years and 69 (47.3%) were female. The median interval from prior surgery to redo aortic valve surgery was 6 years. The aetiologies were pannus formation with prosthetic aortic stenosis in 62 cases (42.5%), prosthetic valve endocarditis (PVE) in five (3.4%), PVE with perivalvular leakage (PVL) in 16 (11.0%), PVL in 45 (30.8%), thrombosis in seven (4.8%), and aortic disease in 11 (7.5%). As for surgical procedure, aortic valve replacement was performed in 81 cases (55.5%), Bentall in 34 (23.3%), PVL repair in six (4.1%), and pannus debridement in 25 (17.1%). Fourteen (14) (9.6%) patients expired perioperatively. Prolonged ventilation time and postoperative renal failure were proved to be significant independent predictors of mortality according to multivariate analysis. Overall survival was 87.8%±7.4% and 76.4%±15.1% at 5 and 10 years, respectively. Survival was 87.7%±13.7% and 84.2%±15.6% in the pannus group, and 84.5%±12.6% and 74.6%±19.4% in the non-pannus group at 5 and 10 years, respectively (p=0.951). Survival was 87.5%±14.2% and 75.8%±22.7% in the PVL group and 84.7%±11.9% and 81.6%±13.5% in the non-PVL group at 5 and 10 years, respectively (p=0.365). CONCLUSIONS: Pannus formation and PVL are two major indications for reoperation of mechanical prosthesis at the aortic position. Redo aortic valve surgery has a satisfactory outcome but with a high risk of complications. Long-term survival of patients seems not to be related to the aetiology. Final decision-making of redo aortic valve surgery should be based on aetiology.

Methicillin-Resistant Staphylococcus aureus Prosthetic Valve Endocarditis: Pathophysiology, Epidemiology, Clinical Presentation, Diagnosis, and Management.

Staphylococcus aureus prosthetic valve endocarditis (PVE) remains among the most morbid bacterial infections, with mortality estimates ranging from 40% to 80%. The proportion of PVE cases due to methicillin-resistant Staphylococcus aureus (MRSA) has grown in recent decades, to account for more than 15% of cases of S. aureus PVE and 6% of all cases of PVE. Because no large studies or clinical trials for PVE have been published, most guidelines on the diagnosis and management of MRSA PVE rely upon expert opinion and data from animal models or related conditions (e.g., coagulase-negative Staphylococcus infection). We performed a review of the literature on MRSA PVE to summarize data on pathogenic mechanisms and updates in epidemiology and therapeutic management and to inform diagnostic strategies and priority areas where additional clinical and laboratory data will be particularly useful to guide therapy. Major updates discussed in this review include novel diagnostics, indications for surgical management, the utility of aminoglycosides in medical therapy, and a review of newer antistaphylococcal agents used for the management of MRSA PVE.