In Vivo Detection of Staphylococcus aureus Infections Using Radiolabeled Antibodies Specific for Bacterial Toxins.

Purpose: The Gram-positive Staphylococcus aureus bacterium is one of the leading causes of infection in humans. The lack of specific noninvasive techniques for diagnosis of staphylococcal infection together with the severity of its associated complications support the need for new specific and selective diagnostic tools. This work presents the successful synthesis of an immunotracer that targets the α-toxin released by S. aureus. Methods: [89Zr]Zr-DFO-ToxAb was synthesized based on radiolabeling an anti-α-toxin antibody with zirconium-89. The physicochemical characterization of the immunotracer was performed by high-performance liquid chromatography (HPLC), radio-thin layer chromatography (radio-TLC), and electrophoretic analysis. Its diagnostic ability was evaluated in vivo by positron emission tomography/computed tomography (PET/CT) imaging in an animal model of local infection-inflammation (active S. aureus vs. heat-killed S. aureus) and infective osteoarthritis. Results: Chemical characterization of the tracer established the high radiochemical yield and purity of the tracer while maintaining antibody integrity. In vivo PET/CT image confirmed the ability of the tracer to detect active foci of S. aureus. Those results were supported by ex vivo biodistribution studies, autoradiography, and histology, which confirmed the ability of [89Zr]Zr-DFO-ToxAb to detect staphylococcal infectious foci, avoiding false-positives derived from inflammatory processes. Conclusions: We have developed an immuno-PET tracer capable of detecting S. aureus infections based on a radiolabeled antibody specific for the staphylococcal alpha toxins. The in vivo assessment of [89Zr]Zr-DFO-ToxAb confirmed its ability to selectively detect staphylococcal infectious foci, allowing us to discern between infectious and inflammatory processes.

Impact of an interventional bundle on complications associated with peripheral venous catheters in elderly patients.

PURPOSE: Elderly patients admitted to geriatrics departments often require peripheral venous catheters (PVC), which should be inserted and maintained following a series of preventive recommendations. Our objective was to evaluate the impact of a training bundle comprising measures aimed at reducing complications associated with the use of PVC in elderly patients admitted to a tertiary teaching hospital. METHODS: We performed a prospective study of patients who received a PVC within 24 h of admission to a geriatrics department. After a 10-month pre-interventional period, we implemented an educational and interventional bundle over a 9-month period. Follow-up was until catheter withdrawal. We analyzed and compared clinical and microbiological data between both study periods. RESULTS: A total of 344 patients (475 PVC) were included (pre-intervention period, 204 patients (285 PVC); post-intervention period, 140 patients (190 PVC)). No statistically significant differences in demographic characteristics were observed between the study periods. The colonization and phlebitis rates per 1000 admissions in both periods were, respectively, 36.7 vs. 24.3 (p = 0.198) and 81.5 vs. 65.1 (p = 0.457). The main reason for catheter withdrawal was obstruction/malfunctioning (33.3%). Obstruction rate was higher for those inserted in the hand than for those inserted at other sites (55.7% vs. 44.3%, p = 0.045). CONCLUSIONS: We found no statistically significant differences regarding phlebitis and catheter tip colonization rates. It is necessary to carry out randomized studies assessing the most cost-effective measure to reduce complications associated with PVC.

Microbiome profile and calprotectin levels as markers of risk of recurrent Clostridioides difficile infection.

Introduction: Clostridioides difficile infection (CDI) is the main cause of nosocomial diarrhoea in developed countries. Recurrent CDI (R-CDI), which affects 20%-30% of patients and significantly increases hospital stay and associated costs, is a key challenge. The main objective of this study was to explore the role of the microbiome and calprotectin levels as predictive biomarkers of R-CDI. Methods: We prospectively (2019-2021) included patients with a primary episode of CDI. Clinical data and faecal samples were collected. The microbiome was analysed by sequencing the hypervariable V4 region of the 16S rRNA gene on an Illumina Miseq platform. Results: We enrolled 200 patients with primary CDI, of whom 54 developed R-CDI and 146 did not. We analysed 200 primary samples and found that Fusobacterium increased in abundance, while Collinsella, Senegalimassilia, Prevotella and Ruminococcus decreased in patients with recurrent versus non-recurrent disease. Elevated calprotectin levels correlated significantly with R-CDI (p=0.01). We built a risk index for R-CDI, including as prognostic factors age, sex, immunosuppression, toxin B amplification cycle, creatinine levels and faecal calprotectin levels (overall accuracy of 79%). Discussion: Calprotectin levels and abundance of microbial genera such as Fusobacterium and Prevotella in primary episodes could be useful as early markers of R-CDI. We propose a readily available model for prediction of R-CDI that can be applied at the initial CDI episode. The use of this tool could help to better tailor treatments according to the risk of R-CDI.

Real-world Use of Bezlotoxumab and Fecal Microbiota Transplantation for the Treatment of Clostridioides difficile Infection.

Background: We aimed to describe the frequency of use and effectiveness of bezlotoxumab (BZX) and fecal microbiota transplantation (FMT) in patients with Clostridioides difficile infection (CDI) in real-world practice. Methods: This was a retrospective study conducted in a university hospital in which adult patients treated with BZX or FMT from January 2018 to April 2021 were included. The primary objective was to evaluate the effectiveness of BZX and FMT in preventing early (within 8 weeks) and late (within 1 year) CDI recurrences (rCDI). A multivariate analysis of risk factors for early recurrence was performed. Results: Of 1377 consecutive CDI episodes, 117 (8.5%) received BZX or FMT, with full information available for 100 of the episodes: 51 received BZX, and 49 received FMT. BZX was used mostly in immunosuppressed patients (66.7%) and in first episodes or first recurrences in 70.6% of the cases. FMT was prescribed only in CDI recurrences. Despite the different conditions of the patients, there were no significant differences between BZX and FMT in preventing early rCDI (19.6% vs 24.5%; P = .55) or late rCDI (9.8% vs 18.4%; P = .31). In the multivariate analysis, risk factors for recurrence were presence of ≥2 previous rCDI episodes (odds ratio [OR], 2.90; 95% CI, 1.03-8.63) and use of non-CDI antibiotics (OR, 3.45; 95% CI, 1.24-9.57). Conclusions: BZX and FMT were infrequently used in real-world practice. Both treatments had similar effectiveness in preventing CDI recurrence despite their application to different populations.

Relevance of [18F]FDG-PET/CT in the detection of colon pathology, in patients studied by bacteriemia or infectious endocarditis caused by enteropathogenic microorganisms.

PURPOSE: Association between S. gallolyticus infective endocarditis (IE) and malignant lesions of the gastrointestinal tract is well described. We hypothesize that other enteropathogenic microorganisms, such as S. viridans and E. faecalis are also related with colorectal pathology. Our aim is to determine the frequency of focal colorectal FDG deposits, suggestive of tumoral lesions and their correlation with colorectal pathology, in patients with infection caused by different commensal microorganisms of the gastrointestinal tract. METHODS: We retrospectively examined 61 patients diagnosed with bacteremia (BSI) and IE (possible or definite) according to Duke's criteria, caused by enteropathogenic microorganisms, who underwent a full-body [18F]FDG-PET/CT in our institution. We looked for colorrectal FDG deposits and morphological lesions. All IE patients underwent a complete colonoscopy and the histological results were classified into four groups: malignant lesion, premalignant lesion, benign lesion and no lesion. We evaluated the correlation between the findings of the [18F]FDG-PET/CT with the histopathological diagnosis and the involved microorganism. RESULTS: PET/CT detected 20 colorectal FDG deposits (32.79%-OR: 47.28), 2 within bacteriemic patients (16.7%) confirmed as malignant and premalignant lesions and 18 in IE group (36.6%), 17 of them corresponding to colorrectal pathology: 11 malignant, 5 premalignant and 1 benign lesions. In the IE subgroup, the colonoscopy detected colorectal lesions in 51.02% of the patients: 11malignant, 8premalignant and 6benign. We found a higher incidence of colorectal FDG deposits in Streptococcus spp. subgroup. Regarding the anatomopathological colonic findings there was a predominance of patients affected by S. viridans, followed by E. faecalis and S. gallolyticus. CONCLUSION: Patients studied by PET/CT for systemic infection, especially IE, caused by S. viridans or E. faecalis, in addition to S. gallolyticus, show a greater probability of presenting incidental colorectal FDG deposits, mostly corresponding to malignant or pre-malignant lesions. Therefore, it is necessary to carry out an exhaustive search of possible colorectal foci in these exams.

Comorbidity and Prognosis in Octogenarians with Infective Endocarditis.

Background. Infective endocarditis (IE) in older patients is associated with a high morbidity, mortality, and functional impairment. The purpose of this study was to describe the current profile of IE in octogenarians and to analyze the prognostic impact of baseline comorbidities in this population. Methods. Patients ≥ 80 years and definite IE from the Spanish IE Prospective Database were included. The effect of Charlson Comorbidity Index (CCI) on in-hospital and 12-month mortality was analyzed. Results. From 726 patients, 357 (49%) had CCI ≥ 3 and 369 (51%) CCI < 3. A total of 265 patients (36.6%) died during hospital admission and 338 (45.5%) during 1-year follow-up. CCI ≥ 3 was an independent predictor of in-hospital and 1-year mortality (odds ratio 1.46, 95% confidence interval 1.07−1.99, p = 0.017; hazard ratio 1.34, 95% confidence interval 1.08−1.66, p = 0.007, respectively). Surgical management was less common in patients with high comorbidity (CCI ≥ 3 68 [19.0%] vs. CCI < 3 112 ((30.4%) patients, p < 0.01). From 443 patients with surgical indication, surgery was only performed in 176 (39.7%). Patients with surgical indication treated conservatively had higher mortality than those treated with surgery (in-hospital mortality: 147 (55.1%) vs. 55 (31.3%), p < 0.001), (1-year mortality: 172 (64.4%) vs. 68 [38.6%], p < 0.001). Conclusion. About half of octogenarians with IE had high comorbidity with CCI ≥ 3. CCI ≥ 3 was a strong independent predictor of in-hospital and 1-year mortality. Our data suggest that the underperformance of cardiac surgery in this group of patients might have a role in their poor prognosis.

SARS-CoV-2 superinfection and reinfection with three different strains.

We report a corona virus disease (COVID-19) case with unprecedented viral complexity. In the first severe episode, two different severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strains (superinfection) were identified within a week. Three months after discharge, the patient was readmitted and was infected in a nosocomial outbreak with a different strain, suffering a second milder COVID-19 episode.

Prevention, Diagnosis and Management of Post-Surgical Mediastinitis in Adults Consensus Guidelines of the Spanish Society of Cardiovascular Infections (SEICAV), the Spanish Society of Thoracic and Cardiovascular Surgery (SECTCV) and the Biomedical Research Centre Network for Respiratory Diseases (CIBERES).

This is a consensus document of the Spanish Society of Cardiovascular Infections (SEICAV), the Spanish Society of Thoracic and Cardiovascular Surgery (SECTCV) and the Biomedical Research Centre Network for Respiratory Diseases (CIBERES). These three entities have brought together a multidisciplinary group of experts that includes anaesthesiologists, cardiac and cardiothoracic surgeons, clinical microbiologists, infectious diseases and intensive care specialists, internal medicine doctors and radiologists. Despite the clinical and economic consequences of sternal wound infections, to date, there are no specific guidelines for the prevention, diagnosis and management of mediastinitis based on a multidisciplinary consensus. The purpose of the present document is to provide evidence-based guidance on the most effective diagnosis and management of patients who have experienced or are at risk of developing a post-surgical mediastinitis infection in order to optimise patient outcomes and the process of care. The intended users of the document are health care providers who help patients make decisions regarding their treatment, aiming to optimise the benefits and minimise any harm as well as the workload.

Clinical Factors Associated with Reinfection versus Relapse in Infective Endocarditis: Prospective Cohort Study.

We aimed to identify clinical factors associated with recurrent infective endocarditis (IE) episodes. The clinical characteristics of 2816 consecutive patients with definite IE (January 2008-2018) were compared according to the development of a second episode of IE. A total of 2152 out of 2282 (94.3%) patients, who were discharged alive and followed-up for at least the first year, presented a single episode of IE, whereas 130 patients (5.7%) presented a recurrence; 70 cases (53.8%) were due to other microorganisms (reinfection), and 60 cases (46.2%) were due to the same microorganism causing the first episode. Thirty-eight patients (29.2%), whose recurrence was due to the same microorganism, were diagnosed during the first 6 months of follow-up and were considered relapses. Relapses were associated with nosocomial endocarditis (OR: 2.67 (95% CI: 1.37-5.29)), enterococci (OR: 3.01 (95% CI: 1.51-6.01)), persistent bacteremia (OR: 2.37 (95% CI: 1.05-5.36)), and surgical treatment (OR: 0.23 (0.1-0.53)). On the other hand, episodes of reinfection were more common in patients with chronic liver disease (OR: 3.1 (95% CI: 1.65-5.83)) and prosthetic endocarditis (OR: 1.71 (95% CI: 1.04-2.82)). The clinical factors associated with reinfection and relapse in patients with IE appear to be different. A better understanding of these factors would allow the development of more effective therapeutic strategies.

Prevalence of Colorectal Neoplasms Among Patients With Enterococcus faecalis Endocarditis in the GAMES Cohort (2008-2017).

OBJECTIVE: To investigate the rate of colorectal neoplasms (CRNs) in patients who have Enterococcus faecalis infective endocarditis (EFIE) with available colonoscopies and to assess whether this is associated with the identification of a focus the infection. PATIENTS AND METHODS: Retrospective analysis of data from a prospective multicenter study involving 35 centers who are members of the Grupo de Apoyo para el Manejo de la Endocarditis en España [Support Group for the Management of Infective Endocarditis in Spain] cohort. A specific set of queries regarding information on colonoscopy and histopathology of colorectal diseases was sent to each participating center. Four-hundred sixty-seven patients with EFIE were included from January 1, 2008, to December 31, 2017, from whom data on colonoscopy performance and results were available in 411 patients. RESULTS: One hundred forty-two (34.5%) patients had a colonoscopy close to the EFIE episode. The overall rate of colorectal diseases was 70.4% (100 of 142), whereas the prevalence of CRN (advanced adenomas and colorectal carcinoma) was 14.8% (21 of 142), with no significant differences between the group of EFIE of unknown focus and that with an identified focus. CONCLUSION: Our study adds to prior evidence suggesting a much higher rate of CRN among patients with EFIE than in the general population of the same age and sex. In addition, our findings suggest that this phenomenon might take place both in EFIE with an unknown and an identified source of infection.

Four weeks versus six weeks of ampicillin plus ceftriaxone in Enterococcus faecalis native valve endocarditis: A prospective cohort study.

Enterococcus faecalis infective endocarditis (EFIE) is a severe disease of increasing incidence. The objective was to analyze whether the outcome of patients with native valve EFIE (NVEFIE) treated with a short course of ampicillin plus ceftriaxone (4wAC) was similar to patients treated according to international guidelines (6wAC). Between January 2008 and June 2018, 1,978 consecutive patients with definite native valve IE were prospectively included in a national registry. Outcomes of patients with NVEFIE treated with 4wAC were compared to those of patients who received 6wAC. Three hundred and twenty-two patients (16.3%) had NVEFIE. One hundred and eighty-three (56.8%) received AC. Thirty-nine patients (21.3%) were treated with 4wAC for four weeks and 70 patients (38.3%) with 6wAC. There were no differences in age or comorbidity. Patients treated 6wAC presented a longer duration of symptoms before diagnosis (21 days, IQR 7-60 days vs. 7 days, IQR 1-22 days; p = 0.002). Six patients presented perivalvular abscess and all of these received 6wAC. Surgery was performed on 14 patients (35.9%) 4wAC and 34 patients (48.6%) 6wAC (p = 0.201). In-hospital mortality, one-year mortality and relapses among 4wAC and 6wAC patients were 10.3% vs. 11.4% (p = 0.851); 17.9% vs. 21.4% (p = 0.682) and 5.1% vs. 4.3% (p = 0.833), respectively. In conclusion, a four-week course of AC may be considered as an alternative regimen in NVEFIE, notably in patients with shorter duration of symptoms and those without perivalvular abscess. These results support the performance of a randomized clinical trial to evaluate the efficacy of this short regimen.

A Contemporary Picture of Enterococcal Endocarditis.

BACKGROUND: Enterococcal endocarditis (EE) is a growing entity in Western countries. However, quality data from large studies is lacking. OBJECTIVES: The purpose of this study was to describe the characteristics and analyze the prognostic factors of EE in the GAMES cohort. METHODS: This was a post hoc analysis of a prospectively collected cohort of patients from 35 Spanish centers from 2008 to 2016. Characteristics and outcomes of 516 cases of EE were compared with those of 3,308 cases of nonenterococcal endocarditis (NEE). Logistic regression and Cox proportional hazards regression analysis were performed to investigate risk factors for in-hospital and 1-year mortality, as well as relapses. RESULTS: Patients with EE were significantly older; more frequently presented chronic lung disease, chronic heart failure, prior endocarditis, and degenerative valve disease; and had higher median age-adjusted Charlson score. EE more frequently involved the aortic valve and prosthesis (64.3% vs. 46.7%; p < 0.001; and 35.9% vs. 28.9%; p = 0.002, respectively) but less frequently pacemakers/defibrillators (1.5% vs. 10.5%; p < 0.001), and showed higher rates of acute heart failure (45% vs. 38.3%; p = 0.005). Cardiac surgery was less frequently performed in EE (40.7% vs. 45.9%; p = 0.024). No differences in in-hospital and 1-year mortality were found, whereas relapses were significantly higher in EE (3.5% vs. 1.7%; p = 0.035). Increasing Charlson score, LogEuroSCORE, acute heart failure, septic shock, and paravalvular complications were risk factors for mortality, whereas prior endocarditis was protective and persistent bacteremia constituted the sole risk factor for relapse. CONCLUSIONS: Besides other baseline and clinical differences, EE more frequently affects prosthetic valves and less frequently pacemakers/defibrillators. EE presents higher rates of relapse than NEE.

Assessment of the anti-biofilm effect of micafungin in an animal model of catheter-related candidemia.

In cases where catheter-related candidemia (CRC) must be managed without catheter withdrawal, antifungal lock therapy using highly active anti-biofilm (HAAB) agents is combined with systemic treatment. However, the activity of HAAB agents has never been studied in in vivo models using bioluminescence. We assessed the efficacy of micafungin using a bioluminescent Candida albicans SKCA23-ACTgLuc strain in an animal model of CRC. We divided 33 female Wistar rats into five groups: sham (A), infected nontreated (B), treated with lock therapy (0.16 mg/ml) (C), systemically treated only (1 mg/kg) (D), and systemically treated+lock (E). Catheters were colonized 24 h before insertion into the femoral vein (day 0). Treatment started on day 1 and lasted 7 days, followed by 7 days of surveillance. Bioluminescence assays were carried out on days 1, 3, 5, and 14, together with daily monitoring of clinical variables. Postmortem microbiological cultures from the catheter and several tissue samples were also obtained. Overall, 28 rats (84.8%) completed the study. Group B animals showed significant weight loss at days 2, 4, and 5 compared with groups C and D (P < .05). In group B, no animals survived after day 7, 75% had CRC, and bioluminescence remained constant 5 days after catheter implantation. Positive catheter culture rates in groups C, D, and E were, respectively, 83.3%, 62.5%, and 25.0% (P = .15). Micafungin proved to be a HAAB agent when administered both systemically and in lock therapy in an animal model of CRC, although the bioluminescence signal persists after treatment. This persistence should be further analyzed.

Current Epidemiology and Outcome of Infective Endocarditis: A Multicenter, Prospective, Cohort Study.

The aim of the study was to describe the epidemiologic and clinical characteristics and identify the risk factors of short-term and 1-year mortality in a recent cohort of patients with infective endocarditis (IE).From January 2008, multidisciplinary teams have prospectively collected all consecutive cases of IE, diagnosed according to the Duke criteria, in 25 Spanish hospitals.Overall, 1804 patients were diagnosed. The median age was 69 years (interquartile range, 55-77), 68.0% were men, and 37.1% of the cases were nosocomial or health care-related IE. Gram-positive microorganisms accounted for 79.3% of the episodes, followed by Gram-negative (5.2%), fungi (2.4%), anaerobes (0.9%), polymicrobial infections (1.9%), and unknown etiology (9.1%). Heart surgery was performed in 44.2%, and in-hospital mortality was 28.8%. Risk factors for in-hospital mortality were age, previous heart surgery, cerebrovascular disease, atrial fibrillation, Staphylococcus or Candida etiology, intracardiac complications, heart failure, and septic shock. The 1-year independent risk factors for mortality were age (odds ratio [OR], 1.02), neoplasia (OR, 2.46), renal insufficiency (OR, 1.59), and heart failure (OR, 4.42). Surgery was an independent protective factor for 1-year mortality (OR, 0.44).IE remains a severe disease with a high rate of in-hospital (28.9%) and 1-year mortality (11.2%). Surgery was the only intervention that significantly reduced 1-year mortality.

The NOVA score: a proposal to reduce the need for transesophageal echocardiography in patients with enterococcal bacteremia.

BACKGROUND: Frequency of enterococcal bloodstream infection (E-BSI) is increasing, and the number of episodes complicated by infective endocarditis (IE) varies. Performing transesophageal echocardiography (TEE) in all patients with E-BSI is costly and time-consuming. Our objectives were to identify patients with E-BSI who are at very low risk of enterococcal IE (and therefore do not require TEE) and to compare the outcome of E-BSI in patients with/without IE. METHODS: Between September 2003 and October 2012, we performed a prospective cohort study (all patients with E-BSI) and a case-control study (patients with/without enterococcal IE) in our center. RESULTS: We detected 1515 patients with E-BSI and 65 with enterococcal IE (4.29% of all episodes of E-BSI, 16.7% of patients with E-BSI who underwent transthoracic echocardiography, and 35.5% of all patients with E-BSI who underwent TEE). We developed a bedside predictive score for enterococcal IE-Number of positive blood cultures, Origin of the bacteremia, previous Valve disease, Auscultation of heart murmur (NOVA) score-based on the following variables: Number of positive blood cultures (3/3 blood cultures or the majority if more than 3), 5 points; unknown Origin of bacteremia, 4 points; prior heart Valve disease, 2 points; Auscultation of a heart murmur, 1 point (receiver operating characteristic = 0.83). The best cutoff corresponded to a score ≥4 (sensitivity, 100%; specificity, 29%). A score <4 points suggested a very low risk for enterococcal IE and that TEE could be obviated. CONCLUSIONS: Enterococcal IE may be more frequent than generally thought. Depending on local prevalence of endocarditis, application of the NOVA score may safely obviate echocardiography in 14%-27% of patients with E-BSI.

Role of (18)F-FDG PET in Patients with Infectious Endocarditis.

UNLABELLED: It was our purpose to evaluate the clinical impact of systematic PET/CT for the diagnosis of infectious embolisms in patients with infectious endocarditis (IE) in comparison with a historic cohort of IE patients managed without this technique. Detection of extracardiac lesions is an essential component of the management and outcome of IE. Studies using PET/CT for the evaluation of patients with IE are scarce, lack a control group, evaluate a small number of patients, or consist of case reports. METHODS: We performed a prospective cohort study (47 patients with definite IE undergoing PET/CT) with matched controls (94 patients with definite IE not undergoing PET/CT) from January 2012 to July 2013 in a tertiary hospital. The results were compared with those of conventional diagnostic techniques and clinical follow-up. RESULTS: PET/CT revealed at least 1 lesion in 35 patients (74.5%): 18 showed an embolic complication, 8 showed pathologic uptake on the valves or cardiac devices, 1 showed both, 5 had incidental noninfectious findings, and the findings for 3 were considered false-positive. The validity values for the efficacy of PET/CT in the diagnosis of septic lesions were as follows: sensitivity, 100%; specificity, 80%; positive predictive value, 90%; and negative predictive value, 100%. PET/CT was the only initially positive imaging technique in 15 true-positive cases (55.5%). The systematic use of PET/CT was associated with a 2-fold reduction in the number of relapses (9.6% vs. 4.2%, P = 0.25) and enabled significantly more infectious complications to be diagnosed (18% vs. 57.4%, P = 0.0001). CONCLUSION: PET/CT enables the extent of IE to be assessed using a single test. It is fast (<2 h) and comfortable for the patient, gathers whole-body data, and detects significantly more infectious complications.

Evaluation of GeneXpert MTB/RIF for the detection of Mycobacterium tuberculosis and resistance to rifampin in clinical specimens.

OBJECTIVES: GeneXpert (GX) is a novel real-time polymerase chain reaction assay for the simultaneous detection of Mycobacterium tuberculosis (MTB) and resistance to rifampin (RIF). We evaluated the performance of GX for direct detection of MTB in respiratory and non-respiratory specimens and assessed the ability of the assay to detect resistance to RIF in non-tuberculosis (TB) endemic country. METHODS: We analyzed 595 clinical samples in a 1550-bed tertiary hospital in Madrid, Spain. Specimens were processed using GX, auramine smear, conventional culture, and drug phenotypic susceptibility testing (DST) with MGIT SIRE (BD). RESULTS: Of the 595 clinical samples, 305 (51.3%) were non-respiratory and 290 (48.7%) were respiratory. In total, MTB was isolated in 81 specimens, 71 of which were positive with GX. The sensitivity, specificity, PPV, and NPV of the GX were: 97.1%, 98.6%, 95.7% and 99.1% for respiratory samples and 33.3%, 99.7%, 80.0% and 97.3% for non-respiratory. GX detected 8 RIF-resistant samples, but only 5 were confirmed by DST. CONCLUSIONS: GX is an accurate, easy-to-apply and rapid test to detect MTB, especially in smear-positive respiratory samples. Although is a useful tool for the rapid identification of RIF-resistant MTB strains, the rifampin resistant results should be confirmed by DST.

The value of combining blood culture and SeptiFast data for predicting complicated bloodstream infections caused by Gram-positive bacteria or Candida species.

Management of complicated bloodstream infections requires more aggressive treatment than uncomplicated bloodstream infections. We assessed the value of follow-up blood culture in bloodstream infections caused by Staphylococcus aureus, Enterococcus spp., Streptococcus spp., and Candida spp. and studied the value of persistence of DNA in blood (using SeptiFast) for predicting complicated bloodstream infections. Patients with bloodstream infections caused by these microorganisms were enrolled prospectively. After the first positive blood culture, samples were obtained every third day to perform blood culture and SeptiFast analyses simultaneously. Patients were followed to detect complicated bloodstream infection. The study sample comprised 119 patients. One-third of the patients developed complicated bloodstream infections. The values of persistently positive tests to predict complicated bloodstream infections were as follows: SeptiFast positive samples (sensitivity, 56%; specificity, 79.5%; positive predictive value, 54%; negative predictive value, 80.5%; accuracy, 72.3%) and positive blood cultures (sensitivity, 30.5%; specificity, 92.8%; positive predictive value, 64%; negative predictive value, 75.5%; accuracy, 73.9%). Multivariate analysis showed that patients with a positive SeptiFast result between days 3 and 7 had an almost 8-fold-higher risk of developing a complicated bloodstream infection. In S. aureus, the combination of both techniques to exclude endovascular complications was significantly better than the use of blood culture alone. We obtained a score with variables selected by the multivariate model. With a cutoff of 7, the negative predictive value for complicated bloodstream infection was 96.6%. Patients with a positive SeptiFast result between days 3 and 7 after a positive blood culture have an almost 8-fold-higher risk of developing complicated bloodstream infections. A score combining clinical data with the SeptiFast result may improve the exclusion of complicated bloodstream infections.