Accuracy of procalcitonin for diagnosing peripheral blood culture contamination among patients with positive blood culture for potential contaminants.

PURPOSE: Blood culture contamination is still a frequently observed event and may lead to unnecessary antibiotic prescriptions and additional hazards and costs. However, in patients hospitalized in tertiary care, true bacteremias for pathogens that are classically considered as contaminants can be observed. We assessed the diagnostic accuracy of procalcitonin for differentiating blood culture contamination from bacteremia in patients with positive blood cultures for potential contaminants. METHODS: We carried out a retrospective, cross-sectional, observational study on consecutive patients hospitalized between January 2016 and May 2019 at the University Hospital of Nancy and who had a positive peripheral blood culture for a pathogen classically considered as a potential contaminant. RESULTS: During the study period, 156 patients were screened, and 154 were retained in the analysis. Among the variables that were significantly associated with a diagnosis of blood culture contamination in univariate analyses, four were maintained in multivariate logistic regression analysis: a number of positive blood culture bottles ≤ 2 (OR 23.76; 95% CI 1.94-291.12; P = 0.01), procalcitonin < 0.1 ng/mL (OR 14.88; 95% CI 1.62-136.47; P = 0.02), non-infection-related admission (OR 13.00; 95% CI 2.17-77.73; P = 0.005), and a percentage of positive blood culture bottles ≤ 25% (OR 12.15; 95% CI 2.02-73.15; P = 0.006). CONCLUSIONS: These data provide new evidence on the usefulness of plasma procalcitonin as a reliable diagnostic biomarker in the diagnostic algorithm of peripheral blood culture contamination among patients hospitalized in tertiary care. CLINICAL TRIAL: ClinicalTrials.gov #NCT04573894.

Clostridium haemolyticum Infection: A Cause of Hemolytic Anemia in a Patient with Bone Marrow Necrosis.

Clostridium haemolyticum is a sporulating Gram-positive anaerobic rod that is considered to be one of the most fastidious and oxygen-sensitive anaerobes. It is a well-known animal pathogen and the cause of bacillary hemoglobinuria primarily in cattle. To date, human infections caused by C. haemolyticum have been reported in three patients with malignant underlying diseases. We present herein the case of a 30-year-old obese woman with no significant past medical history who developed bacteremia caused by C. haemolyticum with massive intravascular hemolysis associated with bone marrow necrosis and acute renal failure. Because of subculture failure, the diagnosis was made on the basis of 16S rDNA sequencing and next-generation sequencing. The patient, who had been afebrile for 20 days after a 17-day-course of antibiotics, experienced a second bacteremic episode caused by C. haemolyticum. After having been successfully treated for 42 days with clindamycin and amoxicillin-clavulanic acid, the patient developed acute myeloid leukemia as a result of bone marrow regeneration. Although uncommon in humans, infections caused by C. haemolyticum are severe and should be considered in a febrile patient who has severe hemolytic anemia. This case also highlights the importance of using molecular techniques for the identification of this fastidious anaerobic organism.

Urinary tract infections in hospitalized inflammatory bowel disease patients: a 10-year experience.

BACKGROUND: Cystitis is the most common genitourinary complication in Crohn's disease (CD). We assessed the prevalence of and risk factors for urinary tract infections (UTI) in inflammatory bowel diseases (IBD). METHODS: Among the 1173 IBD patients of the "Nancy IBD cohort" seen between January 1, 2000 and December 31, 2009, 56 hospitalized patients had 76 documented UTI. Prevalence of UTI in IBD was calculated using rates of UTI among non-IBD patients hospitalized during the same period. The cases were compared to 175 matched IBD patients without UTI hospitalized during the same period to identify risk factors for UTI. RESULTS: Prevalence of UTI was 4% in IBD patients versus 3.3% in non-IBD patients (P = 0.1). Prevalence of UTI was 4.5% and 2.1% in ulcerative colitis (UC) and CD patients, respectively (P = 0.6). Risk factors for UTI in CD patients were perianal disease (odds ratio [OR] = 2.28, 95% confidence interval [CI], 1.06-4.89; P = 0.04) and colonic disease (OR = 2.42, 95% CI, 1.05-5.58; P = 0.04). Male gender (OR = 0.38, 95% CI, 0.17-0.85, P = 0.02) and noncomplicated behavior (OR = 0.26, 95% CI, 0.11-0.60, P = 0.002) were protective factors against UTI in CD. In UC patients, age over 40 years (OR = 9.59, 95% CI, 1.93-47.74; P = 0.006) and disease duration over 11 months (OR = 10.77, 95% CI, 1.68-68.89, P = 0.01) were risk factors for UTI. Male gender was negatively associated with UTI (OR = 0.04, 95% CI, 0.01-0.36, P = 0.00006). CONCLUSIONS: Hospitalized IBD patients are not at increased risk of UTI. Risk factors for UTI include perianal disease and colonic disease in CD and age and longer disease duration in UC.

Gluconobacter as well as Asaia species, newly emerging opportunistic human pathogens among acetic acid bacteria.

Acetic acid bacteria (AAB) are broadly used in industrial food processing. Among them, members of the genera Asaia, Acetobacter, and Granulibacter were recently reported to be human opportunistic pathogens. We isolated AAB from clinical samples from three patients and describe here the clinical and bacteriological features of these cases. We report for the first time (i) the isolation of a Gluconobacter sp. from human clinical samples; (ii) the successive isolation of different AAB, i.e., an Asaia sp. and two unrelated Gluconobacter spp., from a cystic fibrosis patient; and (iii) persistent colonization of the respiratory tract by a Gluconobacter sp. in this patient. We reviewed the main clinical features associated with AAB isolation identified in the 10 documented reports currently available in the literature. Albeit rare, infections as well as colonization with AAB are increasingly reported in patients with underlying chronic diseases and/or indwelling devices. Clinicians as well as medical microbiologists should be aware of these unusual opportunistic pathogens, which are difficult to detect during standard medical microbiological investigations and which are multiresistant to antimicrobial agents. Molecular methods are required for identification of genera of AAB, but the results may remain inconclusive for identification to the species level.

Effects of the TREM-1 pathway modulation during mesenteric ischemia-reperfusion in rats.

OBJECTIVES: The triggering receptor expressed on myeloid cells (TREM)-1, a receptor expressed on the surface of neutrophils and monocytes/macrophages, synergizes with the Toll-like receptors in amplifying the inflammatory response mediated by microbial components. Because the pathogenesis of ischemia-reperfusion-induced gastrointestinal tissue injury and multiple organ failure implies leukocyte activation and bacterial translocation, we hypothesized that the TREM-1 pathway modulation would prove beneficial in this setting. DESIGN: Animal study. SETTING: Research laboratory. SUBJECTS: Adult male Wistar rats (250-300 g). INTERVENTIONS: Rats were subjected to intestinal ischemia-reperfusion induced by occlusion of the superior mesenteric artery during 60 mins and reperfused for 180 mins. At the time of reperfusion, animals were administered with LP17 (a synthetic TREM-1 inhibitor), a control peptide, or a vehicle (normal saline). Plasma concentrations of tumor necrosis factor-alpha, interleukin-6, and soluble TREM-1 were measured by enzyme-linked immunosorbent assay. Hepatic activation of the transcriptional factor nuclear factor-kappaB was assessed by electrophoretic mobility shift assay. Hepatic oxidant-antioxidant balance was estimated by measurement of lipid peroxidation and catalase activity. Ileal mucosal permeability was estimated by fluorescein dextran-4 clearance and bacterial translocation by mesenteric lymph nodes culture. MEASUREMENTS AND MAIN RESULTS: Ischemia-reperfusion was associated with cardiovascular collapse, lactic acidosis, and systemic and hepatic inflammatory response that were partly prevented by LP17 administration. Liver lipid peroxidation and catalase depletion were attenuated by LP17. Ischemia-reperfusion induced a marked increase in ileal mucosal permeability and an associated bacterial translocation that was also prevented by TREM-1 modulation. LP17 delayed mortality. CONCLUSIONS: The modulation of the TREM-1 pathway by the means of a synthetic peptide may be useful during acute mesenteric ischemia.

Modulation of the triggering receptor expressed on myeloid cells-1 pathway during pneumonia in rats.

BACKGROUND: Triggering receptor expressed on myeloid cells-1 (TREM-1) is a cell-surface molecule that has been identified on both human and murine polymorphonuclear neutrophils and mature monocytes. The activation of TREM-1 in the presence of microbial components amplifies the inflammatory response and may be responsible for the hyperresponsiveness observed during the initial stage of sepsis. The aim of the present study was to investigate the effect of the modulation of the TREM-1 pathway during experimental pneumonia in rats. METHODS: Adult male Wistar rats were intratracheally inoculated with Pseudomonas aeruginosa (PAO1 strain) and randomly treated or not treated with an analogue synthetic peptide derived from the extracellular moiety of TREM-1 (LP17). RESULTS: P. aeruginosa induced a severe pneumonia associated with signs of severe sepsis within the first 24 h. In septic rats, LP17 improved hemodynamic status, attenuated the development of lactic acidosis and hypoxemia, modulated lung and systemic inflammatory responses and coagulation activation, reduced lung histological damage, and improved survival. CONCLUSIONS: The modulation of the TREM-1 pathway by the use of such synthetic peptides as LP17 appears beneficial during P. aeruginosa pneumonia in rats in attenuating lung and systemic inflammatory responses.

Sulforaphane inhibits extracellular, intracellular, and antibiotic-resistant strains of Helicobacter pylori and prevents benzo[a]pyrene-induced stomach tumors.

Gastric infection with Helicobacter pylori is a cosmopolitan problem, and is especially common in developing regions where there is also a high prevalence of gastric cancer. These infections are known to cause gastritis and peptic ulcers, and dramatically enhance the risk of gastric cancer. Eradication of this organism is an important medical goal that is complicated by the development of resistance to conventional antimicrobial agents and by the persistence of a low level reservoir of H. pylori within gastric epithelial cells. Moreover, economic and practical problems preclude widespread and intensive use of antibiotics in most developing regions. We have found that sulforaphane [(-)-1-isothiocyanato-(4R)-(methylsulfinyl)butane], an isothiocyanate abundant as its glucosinolate precursor in certain varieties of broccoli and broccoli sprouts, is a potent bacteriostatic agent against 3 reference strains and 45 clinical isolates of H. pylori [minimal inhibitory concentration (MIC) for 90% of the strains is