Impact of [18F] FDG PET/CT on outcomes in patients with Staphylococcus aureus bacteremia: A retrospective single-center experience.

OBJECTIVE: Staphylococcus aureus bacteremia (SAB) is a leading cause of community and hospital-acquired bacteremia with significant morbidity and mortality. Effective management depends on accurate diagnosis, source control and assessment of metastatic infections. [18F] FDG PET/CT has been shown to reduce mortality in high-risk SAB patients. This study aims to evaluate the impact of [18F] FDG PET/CT on outcomes in patients with SAB. METHODS: Single-center, retrospective, real-life setting study including all consecutive SAB cases from 2017 to 2019. Medical records were analyzed to collect information. RESULTS: Out of the 315 included patients, 132 underwent [18F] FDG PET/CT. In those patients, a clear focus of infection was more frequently identified, leading to better adapted treatments and extended hospital stays. Overall mortality rates at 30 days, 90 days and one year were 25.1 %, 36.8 % and 44.8 % respectively. Mortality was significantly lower in the [18F] FDG PET/CT group (p < 0.0001) and persisted (p < 0.05) after adjusting for imbalances between groups regarding oncologic patients and deaths within 7 days. The difference in mortality remained significant irrespective of prolonged bacteremia but was not significant with regard to hospital-acquired SAB. Supplementary analysis using the Cox proportional hazards model confirmed that [18F] FDG PET/CT was significantly associated with reduced mortality (p < 0.05). CONCLUSION: In this real-life cohort, patients with SAB having undergone [18F] FDG PET/CT experienced lower mortality rates, highlighting the additional value of [18F] FDG PET/CT in SAB management. Further research is needed to identify the subpopulations that would benefit most from the integration of [18F] FDG PET/CT in their work-up.

Risk factors for mortality and complications in peripheral venous catheter-associated Staphylococcus aureus bacteraemia: a large multicentre cohort study.

BACKGROUND: Peripheral venous catheter-associated Staphylococcus aureus bacteraemia (PVC-SAB) is a potentially life-threatening nosocomial infection. AIM: This cohort study aims to identify the risk factors associated with its mortality and complications. METHODS: Retrospective analysis of a prospective cohort study conducted at two tertiary-care hospitals in Spain. Adult patients admitted between January 2011 and July 2019 which developed PVC-SAB during their hospital stay were included. Primary outcome was all-cause 30- and 90-day mortality. Secondary outcomes were sepsis or septic shock at the onset of bacteraemia, metastatic infection and length of hospital stay. Univariate and multivariate analyses were performed. FINDINGS: A total of 256 PVC-SAB were diagnosed in 243 patients between 2011 and 2019. Thirty-day and 90-day all-cause mortality were 18.3% and 24.2%, respectively. Lack of susceptible antibiotic administration the day after blood culture collection (odds ratio: 4.14; 95% confidence interval: 1.55-11.03; P = 0.005), sepsis and complicated bacteraemia were identified as independent risk factors for 30- and 90-day mortality; meticillin-resistant S. aureus bacteraemia was identified as an independent risk factor only for 30-day mortality and functional dependence only for 90-day mortality. Persistent bacteraemia and sepsis were associated with septic metastases, which significantly increased hospital stay, and endocarditis. A greater proportion of patients experiencing septic shock were subsequently institutionalized compared to those without. CONCLUSION: PVC-SAB remains linked to high mortality rates. Prompt administration of appropriate antibiotics is crucial for lowering mortality. A comprehensive diagnostic approach is essential, especially in patients with persistent bacteraemia and implanted cardiovascular devices, to rule out metastatic complications and endocarditis.

Validation of a new risk stratification system-based management for methicillin-resistant Staphylococcus aureus bacteraemia: analysis of a multicentre prospective study.

PURPOSE: Distinguishing between complicated and uncomplicated Staphylococcus aureus bacteraemia (SAB) is therapeutically essential. However, this distinction has limitations in reflecting the heterogeneity of SAB and encouraging targeted diagnostics. Recently, a new risk stratification system for SAB metastatic infection, involving stepwise approaches to diagnosis and treatment, has been suggested. We assessed its applicability in methicillin-resistant SAB (MRSAB) patients. METHODS: We retrospectively analysed data of a 3-year multicentre, prospective cohort of hospitalised patients with MRSAB. We classified the patients into three risk groups: low, indeterminate, and high, based on the new system and compared between-group management and outcomes. RESULTS: Of 380 patients with MRSAB, 6.3% were classified as low-, 7.6% as indeterminate-, and 86.1% as high-risk for metastatic infection. No metastatic infection occurred in the low-, 6.9% in the indeterminate-, and 19.6% in the high-risk groups (P < 0.001). After an in-depth diagnostic work-up, patients were finally diagnosed as 'without metastatic infection (6.3%)', 'with metastatic infection (17.4%)', and 'uncertain for metastatic infection (76.3%)'. 30-day mortality increased as the severity of diagnosis shifted from 'without metastatic infection' to 'uncertain for metastatic infection' and 'with metastatic infection' (P = 0.09). In multivariable analysis, independent factors associated with metastatic complications were suspicion of endocarditis in transthoracic echocardiography, clinical signs of metastatic infection, Pitt bacteraemia score ≥ 4, and persistent bacteraemia. CONCLUSIONS: The new risk stratification system shows promise in predicting metastatic complications and guiding work-up and management of MRSAB. However, reducing the number of cases labelled as 'high-risk' and 'uncertain for metastatic infection' remains an area for improvement.

Prostatic abscess Metastasis: A case report of an unusual complication.

Endogenous endophthalmitis, a rare and severe ocular infection, is typically associated with endogenous infections that reach the eye, while prostatic abscesses pose clinical challenges and are more common in immunocompromised patients. We present a case of a 50-year-old male with endophthalmitis resulting from a prostatic abscess. The patient's journey underscores the need for heightened awareness of prostatic abscess in patients with perineal symptoms, especially those with immunosuppression, and the consideration of endophthalmitis as a potential complication in urologic disease. The case highlights the urgent need for standardized guidelines in managing prostatic abscesses, given their complexity and potential for severe complications.

Routine ophthalmologic examination in Klebsiella pneumoniae bacteremia is not necessary: incidence of and risk factors for ocular involvement.

Klebsiella pneumoniae bacteremia is known to present a virulent clinical course, including multiple metastatic infections, which is not uncommon in Asia. However, there are limited data on the incidence and risk factors for ocular involvement in K. pneumoniae bacteremia. We retrospectively reviewed the medical records of all patients with K. pneumoniae bacteremia who underwent ophthalmologic examination in a tertiary center in Seoul, Korea, from February 2012 to December 2020. Two retinal specialists reviewed the findings of the ophthalmologic examinations and classified them as endophthalmitis, chorioretinitis, and no ocular involvement. Of 689 patients, 56 [8.1%; 95% confidence interval (CI) 6.2-10.4] had ocular involvement, and 9 (1.3%; 95% CI 0.6-2.5) were diagnosed with endophthalmitis. Of 47 patients with chorioretinitis, 45 (95.7%) improved with systemic antibiotic therapy alone. Community-onset bacteremia (100% vs 62.1% vs 57.4%, P = 0.04), cryptogenic liver abscess (55.6% vs 11.8% vs 8.5%, P = 0.003), and metastatic infection (66.7% vs 5.8% vs 10.6%, P < 0.001) were more common in endophthalmitis than in no ocular involvement or chorioretinitis. In the multivariable analysis, cryptogenic liver abscess [adjusted odds ratio (aOR), 6.63; 95% CI 1.44-35.20] and metastatic infection (aOR, 17.52; 95% CI 3.69-96.93) were independent risk factors for endophthalmitis. Endophthalmitis was not associated with 30-day mortality. Endophthalmitis is rare in Asian patients with K. pneumoniae bacteremia. Targeted ophthalmologic examination in those with cryptogenic liver abscess, metastatic infection, or ocular symptoms may be more appropriate than routine examination of all patients.

Liver abscess complicated with multiple organ invasive infection caused by hematogenous disseminated hypervirulent Klebsiella pneumoniae: A case report.

Hypervirulent Klebsiella pneumoniae (hvKp) causes increasing infections in healthy individuals from the community. In severe cases, it can cause multiple organ infection with invasive metastasis of blood sources, seriously threatening the patients' life. Rapid and accurate diagnosis of the pathogen becomes the key to timely antibiotic treatment to improve the prognosis. This article reports a case of liver abscess complicated with multiple organ invasive infection caused by hematogenous-disseminated hvKp. K. pneumoniae was identified by culture and metagenomic next-generation sequencing (mNGS) using blood and liver abscess drainage fluid. The isolates from the two samples were subsequently identified with high homology (99.999%) by whole genome sequencing. In addition, multiple virulence genes were detected in the two isolates and the string test was positive, indicating hvKp with hypermucoviscosity phenotype. Multiple antibiotic treatments were given. The conditions of the patient were stable but the temperature remained high. Surgical drainage treatment was performed, and the patient's body temperature immediately dropped to normal. He finally recovered after 6 months of follow-up. mNGS using body fluids can facilitate the rapid diagnosis of pathogens. For hvKp infection, choosing a better antibiotic therapy and receiving surgical drainage can significantly improve the prognosis of the patient.

The Role of the Gut Microbiome on the Development of Surgical Site Infections.

Despite advances in antisepsis techniques, surgical site infection remains the most common and most costly reason for hospital readmission after surgery. Wound infections are conventionally thought to be directly caused by wound contamination. However, despite strict adherence to surgical site infection prevention techniques and bundles, these infections continue to occur at high rates. The contaminant theory of surgical site infection fails to predict and explain most postoperative infections and still remains unproven. In this article we provide evidence that the process of surgical site infection development is far more complex than what can be explained by simple bacterial contamination and hosts' ability to clear the contaminating pathogen. We show a link between the intestinal microbiome and distant surgical site infections, even in the absence of intestinal barrier breach. We discuss the Trojan-horse mechanisms by which surgical wounds may become seeded by pathogens from within one's own body and the contingencies that need to be met for an infection to develop.

Inappropriate empirical antibiotic therapy was an independent risk factor of pediatric persistent S. aureus bloodstream infection.

Persistent S. aureus bloodstream infection (PSBSI) increased the incidence of metastatic infection and mortality. We aimed to clarify its risk factors and correlation with metastatic infection and septic shock in children. This retrospective and observational study enrolled children with S. aureus bloodstream infection who admitted to Children's Hospital of Chongqing Medical University between January 2016 and December 2021. The logistic regression model was used for multivariable analyses to determine independent factors associated with PSBSI and clarify the effect of persistent S. aureus bloodstream infection and other factors on metastatic infection and septic shock. One hundred and twenty-seven children were included in this study retrospectively. There were thirty-two cases in the persistent S. aureus bloodstream infection group and ninety-five children in the non-persistent infection group. Multivariate logistic regression analysis indicated that inappropriate empirical antibiotic therapy (OR, 7.26; 95%CI, 2.48-21.30; P<0.01) was an independent risk factor of persistent S. aureus bloodstream infection. Persistent S. aureus bloodstream infection (OR, 6.40; 95%CI, 2.08-19.70; P<0.01) and community-acquired S. aureus bloodstream infection (OR, 4.75; 95%CI, 1.34-16.89; P=0.02) were independent predictors of metastatic infection. Pittsburgh bacteremia scores ≥ 2 (OR, 28.81; 95%CI, 5.26-157.99; P<0.01), hypoalbuminemia (OR, 13.34; 95%CI, 2.43-73.28; P<0.01) and persistent S. aureus bloodstream infection (OR, 5.48; 95%CI, 1.13-26.54; P=0.04) were independent risk factors of septic shock. CONCLUSION: Inappropriate empirical antibiotic therapy was an independent risk factor of pediatric persistent S. aureus bloodstream infection. Pediatric persistent S. aureus bloodstream infection was associated with metastatic infection and septic shock. WHAT IS KNOWN: • Pathogenic features such as Methicillin-resistant S. aureus and sources of infection such as central venous catheter related infection were risk factors of PSBSI in adults. • PSBSI increased the incidence of metastatic infection and mortality in adults. WHAT IS NEW: • Inappropriate empirical antibiotic therapy was an independent risk factor of pediatric persistent S. aureus bloodstream infection. • Pediatric persistent S. aureus bloodstream infection was associated with metastatic infection and septic shock.

A Severe Case of Disseminated Multifocal Methicillin-Susceptible Staphylococcal Infection in a Diabetic Patient.

Methicillin-susceptible Staphylococcus aureus (MSSA) is quite common in the environment. It can lead to a wide range of infections varying from simple boils to disseminated and metastatic infections. Disseminated multifocal MSSA infection without infective endocarditis is extremely rare. We report a case of a 48-year-old diabetic male who presented with complaints of back pain, lower limb weakness, urinary retention, and saddle sensation loss. His imaging showed an epidural abscess, spondylitis, multiple paraspinous abscess collections, iliopsoas and gluteal abscess formation, multiple abdominal abscesses, multiple cavitating lung nodules, left-sided empyema, and azygos venous thrombosis. He was managed with urgent laminectomy and evacuation of spinal epidural abscess. He was admitted under the medical team for further multidisciplinary patient care. Emergency physicians and internists should be able to recognize such cases early on to make appropriate management plans. Misdiagnosis and delay in treatment initiation can lead to high mortality and poor patient outcomes. Advanced imaging techniques should be utilized to avoid missed foci. Improved source control results in better patient outcomes.

Metastatic spondylodiscitis in central venous catheter related bloodstream infections in hemodialysis patients: Risk factors and prognosis.

BACKGROUND: Infection is one of the most common causes of death in hemodialysis patients. Catheter infections are among the most common infections in this patient group. Spondylodiscitis which has a high incidence in ESRD is more commonly encountered in patients with CVCs compared to AVF. In this study, we aimed to evaluate the frequency and risk factors of spondylodiscitis in catheter-related bloodstream infections in hemodialysis patients. METHODS: In total, 1620 patients were screened and 42 male and 35 female patients with central catheter infection with a mean age of 65.8 ± 14.9 years were included in this study. Patients with metastatic infections secondary to CVC related bloodstream infections were determined. The diagnosis of spondylodiscitis was based on clinical information, computed tomography (CT) and magnetic resonance imaging (MRI), and vertebral cultures. RESULTS: Metastatic infection due to catheter infection was observed in 15 patients (19.5%). In the regression analysis, CRP level and RRT time were found to be significantly correlated with the development of metastatic infection. Spondylodiscitis was the most common subtype of metastatic infections (8/15). The presence of lumbar hernia was associated with increased risk of metastatic spondylodiscitis in case of catheter infection in hemodialysis patients. The only factor associated with resistance to medical treatment was the time from admission to diagnosis. CONCLUSION: Patients with long RRT time and high blood CRP levels on admission should be closely monitored for metastatic infection in patients with CVC related bloodstream infections. Screening for spondylodiscitis with CT or MRI should be performed in patients with symptoms, since early diagnosis may prevent the development of possible neurological deficits and treatment resistance.

Generalized infections of putative oral origin in Helsinki University Hospital in 2012 to 2017.

OBJECTIVE: Bacteria entering the bloodstream through oral mucosa cause bacteremia, which can lead to septic or distant infections. The underlying factors and need for dental treatment in patients referred for oral examination because of septic infection were investigated. It was expected that general diseases and poor socioeconomic status of patients would increase the risk of bacteremia. METHOD AND MATERIALS: This descriptive retrospective study included patients (N = 128) referred from medical clinics of the Helsinki University Hospital (HUH), during 2012 to 2017, to the Department of Oral and Maxillofacial Diseases due to bacteremia suspected to be of oral origin. Data were extracted from medical and dental records according to the World Health Organization International Classification of Diseases (ICD-10) for systemic or remote infections. Different groups were formed using modified Skapinakis classification for socioeconomic status (SES), from I (high) to V (low). Underlying medical conditions were retrieved according to McCabe classification: healthy, nonfatal, ultimately fatal, and rapidly fatal diseases. The data were analyzed using the statistical software package SPSS (IBM). RESULTS: Patients were referred most often from the Departments of Infectious Diseases and Internal Medicine. Because of infection, 12 patients needed aortic or mitral valve operations. Many of the patients were intravenous drug users. However, the majority of patients presented McCabe class I, indicating no systemic disease. The main SES was intermediate III. Tooth extraction was the principal mode of treatment. No demographic background variables were identified to explain increase of the risk for bacteremia except that most patients were men with untreated dental problems. CONCLUSIONS: Contrary to the authors' expectation, poor SES and underlying diseases did not seem to link to the outcome. However, untreated dental infections present an evident risk for life-threatening septic complications also in generally healthy individuals.

Klebsiella pneumoniae Infection as a Mimicker of Multiple Metastatic Lesions.

We describe the case of a 42-year-old man with cirrhosis who presented with fever and imaging concerning for metastatic disease from suspected renal cell carcinoma. He had a right renal mass with multiple pulmonary masses and underwent a lung biopsy and oncology consultation. Blood cultures revealed Klebsiella pneumoniae, and all the lesions disappeared after intravenous (IV) antibiotics. Our case attempts to increase awareness of this unique presentation of invasive Klebsiella infections and discusses host factors that can predispose to this condition.

Individualizing the use of [18F]FDG-PET/CT in patients with complicated Staphylococcus aureus bacteremia: experiences from a tertiary care center.

PURPOSE: [18F]FDG-PET/CT scanning can help detect metastatic infectious foci and reduce mortality in patients with Staphylococcus aureus bacteremia (SAB), but it is unknown if patients with SAB and an indication for prolonged treatment because of possible endovascular, orthopaedic implant, or other metastatic infection still need [18F]FDG-PET/CT. METHODS: In a retrospective single-center cohort study, we included all consecutive adult patients with SAB between 2013 and 2020 if an [18F]FDG-PET/CT scan was performed and antibiotic treatment was planned for ≥ 6 weeks prior to [18F]FDG-PET/CT. We aimed to identify patients for whom treatment was adjusted due to the results of [18F]FDG-PET/CT, and assessed concordance of [18F]FDG-PET/CT and clinical diagnosis for infected prosthetic material. RESULTS: Among 132 patients included, the original treatment plan was changed after [18F]FDG-PET/CT in 22 patients (16.7%), in the majority (n = 20) due to diagnosing or rejecting endovascular (graft) infection. Antibiotic treatment modifications were shortening in 2, iv-oral switch in 3, extension in 13, and addition of rifampicin in 4 patients. Ninety additional metastatic foci based on [18F]FDG-PET/CT results were found in 69/132 patients (52.3%). [18F]FDG-PET/CT suggested vascular graft infection in 7/14 patients who lacked clinical signs of infection, but showed no infection of prosthetic joints or osteosynthesis material in eight patients who lacked clinical signs of such an infection. CONCLUSION: [18F]FDG-PET/CT can help refine treatment for SAB in patients with clinically suspected endovascular infection or vascular grafts, even if 6 weeks treatment is already indicated, but can be safely omitted in other patients who are clinically stable.

The first case of abdominal mycotic aneurysm caused by K1 hypervirulent Klebsiella pneumoniae in a healthy adult.

Incidence of hypervirulent Klebsiella pneumoniae (hvKp) infection has been steadily increasing in the Asia-Pacific rim. The characteristic of hvKp infection is its ability to cause multiple site infections and unpredictable metastatic spread in the community. We describe the first case of mycotic aneurysm caused by hvKp serotype K1 in a previously healthy man and review the literature. Of a total of 13 cases, including our case, three cases were related to hvKp. Among patients with hvKp, the level of mycotic aneurysm in most patients was the infrarenal aorta, and they underwent an aortic graft or coil embolization. All strains were susceptible to most antimicrobial agents, except ampicillin. Early detection of hvKp can help to prevent the metastatic spread of pathogens and be useful for optimal patient care and epidemiologic research.

Clinical features and development of Sepsis in Klebsiella pneumoniae infected liver abscess patients: a retrospective analysis of 135 cases.

BACKGROUND: Klebsiella pneumoniae is a primary pathogen of pyogenic liver abscess (PLA). However, little data are available on combination with sepsis. In this study, we aimed to evaluate the clinical characteristics and prognostic differences of PLA patients with sepsis. METHODS: This retrospective cohort study was conducted to investigate 135 patients with confirmed Klebsiella pneumoniae-caused liver abscesses (KPLA) from a tertiary teaching hospital, from 2013 to 2019. The patients were divided into two groups, KPLA with sepsis and KPLA without sepsis. The demographic characteristics, clinical features as well as laboratory and microbiologic findings were analyzed. RESULTS: A total of 135 patients with KPLA were analyzed. The mean age of patients was 60.9 ± 12.7 years, and the percentage of men was 59.3%. Among them, 37/135 (27.4%) of patients had sepsis and the mortality rate was 1.5%. The most common symptom was fever (91.1%). KPLA patients with sepsis had a significantly higher proportion of frailty, diarrhea, fatty liver, chronic renal insufficiency, and hepatic dysfunction compared to KPLA patients without sepsis (p < 0.05). Antibiotic therapy and percutaneous drainage were most frequently therapeutic strategy. Furthermore, the incidences of sepsis shock and acute respiratory distress syndrome were higher in the sepsis group compared to the non-sepsis group. As for metastatic infections, the lung was the most common site. In addition, KPLA patients with sepsis showed respiratory symptoms in 11 patients, endophthalmitis in 4 patients, and meningitis in 1 patient. CONCLUSION: Our findings emphasize that KPLA patients combined with or without sepsis have different clinical features, but KPLA patients with sepsis have higher rates of complications and metastatic infections. Taken together, further surveillance and control of septic spread is essential for KPLA patients.

The Surface Protein Fructose-1, 6 Bisphosphate Aldolase of Klebsiella pneumoniae Serotype K1: Role of Interaction with Neutrophils.

Hypermucoviscosity phenotypic Klebsiella pneumoniae (HV-Kp) serotype K1 is the predominant pathogen of a pyogenic liver abscess, an emerging infectious disease that often complicates septic metastatic syndrome in diabetic patients with poor sugar control. HV-Kpisolates were more resistant to neutrophil phagocytosis than non-HV-Kpisolates because of different pathogen-associated molecular patterns. The protein expression of HV-Kp after interaction with neutrophils is unclear. We studied KP-M1 (HV phenotype; serotype K1), DT-X (an acapsularmutant strain of KP-M1), and E. coli (ATCC 25922) with the model of Kp-infected neutrophils, using a comparative proteomic approach. One the identified protein, namely fructose-1, 6-bisphosphate aldolase (FBA), was found to be distributed in the KP-M1 after infecting neutrophils. Cell fractionation experiments showed that FBA is localized both to the cytoplasm and the outer membrane. Flow cytometry demonstrated that outer membrane-localized FBA was surface-accessible to FBA-specific antibody. The fba gene expression was enhanced in high glucose concentrations, which leads to increasing bacterial resistance to neutrophils phagocytosis and killing. The KP-M1 after FBA inhibitors and FBA-specific antibody treatment showed a significant reduction in bacterial resistance to neutrophils phagocytosis and killing, respectively, compared to KP-M1 without treatment. FBA is a highly conserved surface-exposed protein that is required for optimal interaction of HV-Kp to neutrophils.

Persistent vs non-persistent candidaemia in adult patients in 2007-2016: A retrospective cohort study.

OBJECTIVES: Persistent candidaemia (PC) is a recognised complication of candidaemia. Our objective was to evaluate risk factors and clinical significance of PC in adult patients. METHODS: This is a retrospective, cohort study. We compared PC with non-PC. All patients with blood cultures positive for Candida species were identified from a microbiological database in the hospital district of Helsinki and Uusimaa from 2007 to 2016. PC was defined as an isolation of the same Candida species from positive blood culture for ≥5 days. RESULTS: PC criteria were fulfilled by 75/350 patients (21.4%). No significant difference emerged between persistent and non-persistent cases caused by non-albicans Candida species (37.3% vs 35.1%, P = .742). The length of hospital stay before onset of candidaemia was longer before PC (hospital stay > 7 days; 73.3% vs 59.6%, P = .043). No significant impact on 30-day mortality was observed (20.0% vs 15.5%, P = .422). Using multivariable regression analysis, we found the presence of central venous catheter (CVC) (OR = 2.71, 95% CI 1.31-5.59), metastatic infection foci (OR 3.60, 95% CI 1.66-7.79) and ineffective empirical treatment (OR = 3.31, 95% CI 1.43-7.65) to be independent risk factors for PC. In subgroup analysis, early source control was identified as a protective factor against PC (30.5% vs 57.7%, P = .002). CONCLUSION: The presence of CVC, metastatic infection foci and ineffective empirical treatment were independently associated with PC in adult patients. Active search for and treatment of metastatic infection foci and removal of CVC are key elements for preventing PC.

Metastatic infection during Staphylococcus aureus bacteremia.

Staphylococcus aureus causes various infections, including skin and soft tissue infections and pneumonia via both, community-associated and nosocomial infection. These infectious diseases can lead to bacteremia, and may subsequently result in metastatic infections in several cases. Metastatic infections are critical complications in patients with S. aureus bacteremia, since the optimal duration of the antimicrobial treatment differs in patients with and without metastatic infection. Notably, two weeks of antimicrobial treatment is recommended in case of uncomplicated S. aureus bacteremia, whereas in patients with S. aureus bacteremia-associated endocarditis or vertebral osteomyelitis, six weeks of antimicrobial administration is vital. In addition, misdiagnosis or insufficient treatment in metastatic infection is associated with poor prognosis, functional disability, and relapse. Although echocardiography is recommended to examine endocarditis in the patients with S. aureus bacteremia, it remains unclear which patients should undergo additional examinations, such as CT and MRI, to detect the presence of other metastatic infections. Clinical studies have revealed that permanent foreign body and persistent bacteremia are predictive factors for metastatic infections, and experimental studies have demonstrated that the virulence factors of S. aureus, such as fnbA and clfA, are associated with endocarditis; however, these factors are not proven to increase the risk of metastatic infections. In this review, we assessed the incidence, predictive factors, diagnosis, and treatment for metastatic infections during S. aureus bacteremia.

Metastatic infection caused by hypervirulent Klebsiella pneumonia and co-infection with Cryptococcus meningitis: A case report.

BACKGROUND: Klebsiella pneumoniae (K. pneumoniae) used to affect mainly people with compromised immunity or weakened by other infections, but recent emergence of hypervirulent strains has increased infections even in healthy individuals. These infections include liver abscess, pneumonia, bacteremia, meningitis, necrotizing fasciitis, and endophthalmitis. Although metastatic infection by hypervirulent K. pneumoniae (hvKP) is increasingly recognized, co-infection with Cryptococcus neoformans (C. neoformans) meningitis in immunocompetent hosts is rare but fatal. So, it is necessary to determine the risk factors, complications, and comorbidity of this disease. CASE SUMMARY: This report describes a 58-year-old man with hvKP pulmonary abscess, bacteremia, and meningitis, accompanied by fatal Cryptococcus meningitis. This patient presented with fever for 1 wk and drowsiness for 3 d. Laboratory findings revealed pulmonary abscess and bacteremia of K. pneumoniae. He was given intravenous antibiotic therapy, and the infection was under control for about 1 wk. However, his condition deteriorated rapidly because of metastatic purulent meningitis. Although hvKP and C. neoformans were isolated and confirmed, the patient died of spontaneous respiratory and cardiac arrest caused by cerebral hernia. CONCLUSION: HvKP has emerged as a cause of metastatic infections in immunocompetent hosts. polymicrobial co-infections should be taken into consideration when metastatic infection is present.

18F-FDG PET/CT-Guided Treatment Duration in Patients with High-Risk Staphylococcus Aureus Bacteremia: A Proof of Principle.

Current guidelines recommend intravenous antibiotic therapy for at least 4 wk in patients with high-risk Staphylococcus aureus bacteremia (SAB), because of the risk for metastatic infection. We evaluated the safety of a shorter duration of treatment in patients with high-risk SAB without signs of metastatic infection at presentation, using standard 18F-FDG PET/CT and echocardiography. Methods: Retrospective analyses were performed of patients with SAB admitted between 2013 and 2017 in 2 medical centers. Patients with risk factors for complicated bacteremia (community acquisition, persistently positive blood cultures, >72 h of fever, or foreign body materials present), a normal echocardiography result, and 18F-FDG PET/CT without signs of metastatic infection were included (cases) and compared with patients with uncomplicated bacteremia (absence of any of the risk factors and no known metastatic disease, controls). Primary outcomes were 3-mo SAB-specific mortality rate and recurrent infection. The secondary outcome was overall mortality. Results: We included 36 cases and 40 controls. Both groups had a similar treatment duration (15.9 vs. 15.4 d). No deaths occurred as a consequence of SAB in the cases, compared with 1 in the control group. One relapse occurred in the case group and 2 in the control group. Overall mortality did not differ between the groups (19.4% vs. 15.0%, P = 0.64). Conclusion: This study suggests that intravenous treatment for 2 wk in high-risk patients with SAB without endocarditis and absence of metastatic infection on 18F-FDG PET/CT is safe. A diagnostic-driven approach using 18F-FDG PET/CT to determine treatment duration in high-risk SAB seems feasible and allows tailoring treatment to individual patients.