Estimation of missed bloodstream infections without the third blood culture set: a retrospective observational single-centre study.

OBJECTIVES: The question of whether to obtain two or three sets of blood cultures to assess the aetiology of bloodstream infections (BSIs) remains open to debate. Few studies have assessed the proportion of BSIs missed without the third blood culture set (BCS). The aim of our study was to determine the proportion of BSIs that would be missed without the third BCS in a hospital where obtaining three BCSs is the standard of care. METHODS: We performed a descriptive retrospective study in Hospital Gregorio Marañón (Madrid) from 2010 to 2013. We included all episodes of BSI in which three BCSs were systematically obtained. RESULTS: We included 4000 episodes of BSI between 2010 and 2013. Without the third BCS, we would have missed 298 (7.5%) episodes of BSI: 141 (47.3%) by gram-positive microorganisms, 147 (49.3%) by gram-negative microorganisms, and 10 (3.4%) by yeasts. In 132/298 (44.3%) of the episodes another clinical sample was obtained within a week of the BCS extraction; in 101/298 (33.9%), the same microorganism was present in a significant clinical sample other than blood. CONCLUSIONS: Our data suggest that performing a third BCS is useful, as not doing this could result in an unacceptable number of BSIs going undetected.

Should non-bacteraemic patients with a colonized catheter receive antimicrobial therapy?

OBJECTIVES: The impact of antimicrobial therapy on the outcomes of patients with colonized catheters and no bacteraemia has not been assessed. This study assessed whether targeted antibiotic therapy is related to a poor outcome in patients with positive cultures of blood drawn through a non-tunnelled central venous catheter (CVC) and without concomitant bacteraemia. METHODS: This was a retrospective study involving adult patients with positive blood cultures drawn through a CVC and negative peripheral vein blood cultures. Patients were classified into two groups: those with clinical improvement and those with a poor outcome. These two groups were compared. The outcome was considered poor in the presence of one or more of the following: death, bacteraemia or other infection due to the same microorganism, and evidence of catheter-related bloodstream infection. RESULTS: A total of 100 patients were included (31 with a poor outcome). The only independent predictors of a poor outcome were a McCabe and Jackson score of 1-2 and a median APACHE score of 5. No association was found between the use of targeted antimicrobial therapy and a poor outcome when its effect was adjusted for the rest of the variables. CONCLUSIONS: This study showed that antimicrobial therapy was not associated with a poor outcome in non-bacteraemic patients with positive blood cultures drawn through a CVC.

An outbreak of Clostridium difficile PCR ribotype 027 in Spain: risk factors for recurrence and a novel treatment strategy.

An outbreak of Clostridium difficile infection (CDI) caused by ribotype 027 (B1/NAP1) began in our hospital in November 2014, and produced 141 episodes in the following months. The aim of this study is to describe this outbreak, assess risk factors for recurrence of CDI-027 and to analyze the implementation of a novel treatment strategy. This is a prospective study of all patients with CDI-027, from November 2014 to November 2015. The epidemiological data were collected daily for each patient. We compared clinical characteristics and treatment between patients with and without recurrence of CDI-027. Interestingly, liver cirrhosis was present in 22% of the patients, and most of them received prophylaxis for hepatic encephalopathy with rifaximin. Patients were also taking antimicrobial drugs (93.6%) and proton pump inhibitors (80.1%). Overall, 27 (23.5%) patients had a first recurrence of CDI-027. Liver cirrhosis increased the risk of recurrence (44.4% vs 14.8%). Patients treated with a prolonged oral vancomycin regimen vs the conventional regimen (oral metronidazole or 10 days of vancomycin) had fewer recurrences (8.6 versus 44.7% [p ≤ 0.01]; OR, 0.91; 95% CI, 0.028-0.294) and less attributable mortality (0% versus 7.1%; p = 0.058). We report an outbreak of CDI-027, mainly in patients with liver cirrhosis. Recurrence of CDI-027 was more common in those patients. A novel approach involving high-dose prolonged vancomycin taper as a first-line treatment, together with a bundle of outbreak measures, seemed to reduce the number of cases of CDI-027, recurrences, and attributable mortality. Nevertheless, this approach warrants further investigation.

Association between source control and mortality in 258 patients with intra-abdominal candidiasis: a retrospective multi-centric analysis comparing intensive care versus surgical wards in Spain.

Early empiric therapy and adequate resuscitation have been identified as main predictors of outcome in patients with candidemia or bacteremia. Moreover, source control is a major determinant in infectious sites when feasible, as a main technique to reduce microbiological burden. A retrospective, multicenter, cohort study was performed at surgical wards and intensive care units (ICU) of three University Hospitals in Spain between 2010 and 2014, with the aim of improving understanding of the interaction between source control, early antifungal therapy, and use of vasoactives in patients with intra-abdominal candidiasis (IAC). Source control was defined as all physical actions taken to control a focus of infection and reduce the favorable conditions that promote microorganism growth or that maintain the impairment of host defenses. Two hundred and fifty-eight patients with IAC were identified. Sixty-one patients were at ICU for diagnosis. Mortality was higher in the ICU group compared to what was documented for the non-ICU group (35 % vs 19.5 %, p = 0011). Adequate source control within 48 h of diagnosis was achieved in 60 % of the cohort. In multivariate analysis, inadequate source control was identified as the only common risk factor for 30-day mortality in both groups (ICU group OR: 13.78 (95% CI: 2.60-72.9, p = 0.002) and non-ICU group OR: 6.53 (95% CI: 2.56-16.61, p = <0.001). The population receiving both adequate source control and adequate antifungal treatment was the one associated with a higher survival rate, in both the ICU and surgical groups. Source control remains a key element in IAC, inside and outside the intensive care unit. Early antifungal treatment among ICU patients was associated with lower mortality.

Influenza A and B co-infection: a case-control study and review of the literature.

Influenza virus infection remains a major cause of morbidity and mortality during winter seasons. Bacterial and virus co-infection is a commonly described situation in these patients. However, data on co-infection by influenza A and B viruses are lacking. In this study, we present the cases of co-infection by influenza A and B viruses during the winter season of 2014-2015 in our institution. We analyzed 2759 samples from 2111 patients and found that 625 samples corresponding to 609 patients were positive for influenza A or B virus. A total of 371 patients had influenza A, 228 had influenza B, and 10 (1.6 %) had influenza A and B virus detection in the same sample. The median age of co-infected patients was 78.6 years, and only one of the co-infected patients died because of the infection. Comparison with a control group of mono-infected patients revealed that co-infection was significantly associated with nosocomial acquisition [odds ratio (OR) = 4.5, 95 % confidence interval (CI) = 1.05-19.25, p = 0.042]. However, co-infection was not associated with worse outcome, previous underlying condition, or vaccination status. Multivariate analysis revealed that co-infection was not an independent risk factor for death and that no single risk factor could predict co-infection.

Is Clostridium difficile infection an increasingly common severe disease in adult intensive care units? A 10-year experience.

PURPOSE: Despite the high concentration of patients with known risk factors for Clostridium difficile infection (CDI) in intensive care units (ICUs), data on ICU patients are scarce. The aim of this study was describe the incidence, clinical characteristics, and evolution of CDI in critically ill patients. MATERIALS AND METHODS: From 2003 to 2012, adult patients admitted to an ICU (A-ICU) and positive for CDI were included and classified as follows: pre-ICU, if the positive sample was obtained within ±3 days of ICU admission; in-ICU, if obtained after 3 days of ICU admission and up to 3 days after ICU discharge. RESULTS: We recorded 4095 CDI episodes, of which 328 were A-ICU (8%). Episodes of A-ICU decreased from 19.4 to 8.7 per 10000 ICU days of stay (P < .0001). Most A-ICU CDIs (66.3%) were mild to moderate. Pre-ICU episodes accounted for 16.2% and were more severe complicated than in-ICU episodes (11% vs 0%; P = .020). Overall mortality was 28.6%, and CDI-attributable mortality was only 3%. CONCLUSION: The incidence of A-ICU CDI has decreased steadily over the last 10 years. A significant proportion of A-ICU CDI episodes are pre-ICU and are more severe than in-ICU CDI episodes. Most episodes of A-ICU CDI were nonsevere, with low associated mortality.

An algorithm to diagnose influenza infection: evaluating the clinical importance and impact on hospital costs of screening with rapid antigen detection tests.

Rapid antigen detection tests (RADTs) are immunoassays that produce results in 15 min or less, have low sensitivity (50 %), but high specificity (95 %). We studied the clinical impact and laboratory savings of a diagnostic algorithm for influenza infection using RADTs as a first-step technique during the influenza season. From January 15th to March 31st 2014, we performed a diagnostic algorithm for influenza infection consisting of an RADT for all respiratory samples received in the laboratory. We studied all the patients with positive results for influenza infection, dividing them into two groups: Group A with a negative RADT but positive reference tests [reverse transcription polymerase chain reaction (RT-PCR) and/or culture] and Group B with an initial positive RADT. During the study period, we had a total of 1,156 patients with suspicion of influenza infection. Of them, 217 (19 %) had a positive result for influenza: 132 (11 %) had an initial negative RADT (Group A) and 85 (7 %) had a positive RADT (Group B). When comparing patients in Group A and Group B, we found significant differences, as follows: prescribed oseltamivir (67 % vs. 82 %; p = 0.02), initiation of oseltamivir before 24 h (89 % vs. 97 %; p = 0.03), antibiotics prescribed (89 % vs. 67 %; p = <0.01), intensive care unit (ICU) admissions after diagnosis (23 % vs. 14 %; p = 0.05), and need for supplementary oxygen (61 % vs. 47 %; p = 0.01). An influenza algorithm including RADTs as the first step improves the time of administration of proper antiviral therapy, reduces the use of antibiotics and ICU admissions, and decreases hospital costs.

Isolation of Pseudobutyrivibrio ruminis and Pseudobutyrivibrio xylanivorans from rumen of Creole goats fed native forage diet.

We isolated and identified functional groups of bacteria in the rumen of Creole goats involved in ruminal fermentation of native forage shrubs. The functional bacterial groups were evaluated by comparing the total viable, total anaerobic, cellulolytic, hemicellulolytic, and amylolytic bacterial counts in the samples taken from fistulated goats fed native forage diet (Atriplex lampa and Prosopis flexuosa). Alfalfa hay and corn were used as control diet. The roll tubes method increased the possibility of isolating and 16S rDNA gene sequencing allowed definitive identification of bacterial species involved in the ruminal fermentation. The starch and fiber contents of the diets influenced the number of total anaerobic bacteria and fibrolytic and amylolytic functional groups. Pseudobutyrivibrio ruminis and Pseudobutyrivibrio xylanivorans were the main species isolated and identified. The identification of bacterial strains involved in the rumen fermentation helps to explain the ability of these animals to digest fiber plant cell wall contained in native forage species.

TNF-α respecifies human mesenchymal stem cells to a neural fate and promotes migration toward experimental glioma.

Bone marrow-derived human mesenchymal stem cells (hMSCs) have become valuable candidates for cell-based therapeutical applications including neuroregenerative and anti-tumor strategies. Yet, the molecular mechanisms that control hMSC trans-differentiation to neural cells and hMSC tropism toward glioma remain unclear. Here, we demonstrate that hMSCs incubated with 50 ng/ml tumor necrosis factor alpha (TNF-α) acquired astroglial cell morphology without affecting proliferation, which was increased at 5 ng/ml. TNF-α (50 ng/ml) upregulated expression of numerous genes important for neural cell growth and function including LIF (leukemia inhibitory factor), BMP2 (bone morphogenetic protein 2), SOX2 (SRY box 2), and GFAP (glial fibrillary acidic protein), whereas NES (human nestin) transcription ceased suggesting a premature neural phenotype in TNF-α-differentiated hMSCs. Studies on intracellular mitogen-activated protein kinase (MAPK) signaling revealed that inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) activity abolished the TNF-α-mediated regulation of neural genes in hMSCs. In addition, TNF-α significantly enhanced expression of the chemokine receptor CXCR4 (CXC motive chemokine receptor 4), which facilitated the chemotactic invasiveness of hMSCs toward stromal cell-derived factor 1 (SDF-1) alpha. TNF-α-pretreated hMSCs not only exhibited an increased ability to infiltrate glioma cell spheroids dependent on matrix metalloproteinase activity in vitro, but they also showed a potentiated tropism toward intracranial malignant gliomas in an in vivo mouse model. Taken together, our results provide evidence that culture-expansion of hMSCs in the presence of TNF-α triggers neural gene expression and functional capacities, which could improve the use of hMSCs in the treatment of neurological disorders including malignant gliomas.