The virulence of methicillin-resistant
(MRSA) and its potentially fatal outcome necessitate rapid and accurate detection of patients colonized with MRSA in healthcare settings. Using the BD Kiestra ...Total Lab Automation (TLA) System in conjunction with the MRSA Application (MRSA App), an imaging application that uses artificial intelligence to interpret colorimetric information (mauve-colored colonies) indicative of MRSA pathogen presence on CHROMagar chromogenic media, anterior nares specimens from three sites were evaluated for the presence of mauve-colored colonies. Results obtained with the MRSA App were compared to manual reading of agar plate images by proficient laboratory technologists. Of 1,593 specimens evaluated, 1,545 (96.98%) were concordant between MRSA App and laboratory technologist reading for the detection of MRSA growth sensitivity 98.15% (95% CI, 96.03, 99.32) and specificity 96.69% (95% CI, 95.55, 97.60). This multi-site study is the first evaluation of the MRSA App in conjunction with the BD Kiestra TLA System. Using the MRSA App, our results showed 98.15% sensitivity and 96.69% specificity for the detection of MRSA from anterior nares specimens. The MRSA App, used in conjunction with laboratory automation, provides an opportunity to improve laboratory efficiency by reducing laboratory technologists' labor associated with the review and interpretation of cultures.
Blood cultures are one of the most common and most important tests performed in clinical microbiology laboratories. Variables and technology that improve and speed the recovery of blood stream ...pathogens have been published in the Journal of Clinical Microbiology since its inception in 1975. Despite the importance of blood cultures, little research has focused on the turnaround time of blood culture reports. In this issue of the Journal of Clinical Microbiology, Y. P. Tabak et al. (J Clin Microbiol 56:e00500-18, 2018, https://doi.org/10.1128/JCM.00500-18) report the results of an investigation of Gram stain, organism identification, and susceptibility report turnaround times for 165,593 blood cultures from 13 laboratories. These data provide a starting point for clinical laboratories to establish targets for blood culture result reporting.
1 Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Duke University Medical Center, and 2 Veterans Affairs Medical Center, Durham, North Carolina
Submitted 11 ...January 2005
; accepted in final form 11 April 2005
Although chronic inhalation of endotoxin or lipopolysaccharide (LPS) causes all of the classic features of asthma, including airway hyperreactivity, airway inflammation, and airway remodeling, the mechanisms involved in this process are not clearly understood. The objective of this study was to determine whether intratracheal treatment with LPS antagonist (E5564, a lipid A analog) prevented the development of chronic endotoxin-induced airway disease in a mouse model of environmental airway disease. Pretreatment with 10 and 100 µg of E5564 was found to inhibit the airway response (hyperreactivity and inflammation) for up to 48 h after the administration of the compound. Repeated dosing with 50 µg of E5564 intratracheally did not cause any measurable toxicity. Therefore, in a chronic experiment, mice were treated with either E5564 (50 µg) or vehicle three times weekly for 5 wk and simultaneously daily exposed to either LPS (4.65 ± 0.30 µg/m 3 ) or saline aerosol. E5564 was effective in decreasing the airway hyperreactivity to methacholine, the air space neutrophilia, the interleukin-6 in the lung lavage fluid, and the neutrophil infiltration of the airways 36 h after 5 wk of LPS inhalation. Less collagen deposition was observed in the airways of E5564-treated mice compared with vehicle-treated mice after a 4-wk recovery period. Our results indicate that E5564, a Toll-like receptor 4 antagonist, minimizes the physiological and biological effects of chronic LPS inhalation, suggesting a therapeutic role for competitive LPS antagonists in preventing or reducing endotoxin-induced environmental airway disease.
endotoxin; asthma; airway inflammation; airway remodeling; airway pressure-time index; lipid A
Address for reprint requests and other correspondence: D. M. Brass, National Institute of Environmental Health Services, PO Box 12233, Research Triangle Park, NC 27709 (e-mail: brassd{at}niehs.nih.gov )
Fibrinolysis in LPS-induced chronic airway disease Savov, Jordan D; Brass, David M; Berman, Katherine G ...
American journal of physiology. Lung cellular and molecular physiology,
10/2003, Letnik:
285, Številka:
4
Journal Article
Recenzirano
Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Duke University Medical Center and Veterans Administration Medical Center, Durham, North Carolina 27710
Submitted 7 ...April 2003
; accepted in final form 20 June 2003
To examine the role of the fibrinolytic system in LPS-induced airway disease, we compared the effect of a chronic LPS challenge in plasminogen activator inhibitor-deficient (C57BL/6J PAI-1-/- ) mice and wild-type (WT) C57BL/6J mice. Physiological and biological assessments were performed, immediately after, and 4 wk after an 8-wk exposure to LPS or saline. Immediately after the LPS exposure, WT mice had increased estimates of airway reactivity to methacholine compared with C57BL/6J PAI-1-/- mice; however, airway inflammation was similar in both LPS-exposed groups. Significant increases in both active transforming growth factor (TGF)- 1 and active matrix metalloproteinase (MMP)-9 was detected after LPS exposure in WT but not C57BL/6J PAI-1-/- mice. C57BL/6J PAI-1-/- mice showed significantly less TGF- 1 in the lavage and higher MMP-9 in the lung tissue than WT mice at the end of exposure and 4 wk later. After LPS exposure, both WT and C57BL/6J PAI-1-/- mice had substantial expansion of the subepithelial area of the medium diameter (d) = 90-129 µm- and large (d > 129 µm)-size airways when compared with saline-exposed mice. Subepithelial fibrin deposition was prevalent in WT mice but diminished in C57BL/6J PAI-1-/- . PAI-1 expression by nonciliated bronchial epithelial cells was enhanced in LPS-exposed WT mice compared with the saline-exposed group. Four weeks after LPS inhalation, airway hyperreactivity and the expansion of the subepithelial area in the medium and large airways persisted in WT but not C57BL/6J PAI-1-/- mice. We conclude that an active fibrinolytic system can substantially alter the development and resolution of the postinflammatory airway remodeling observed after chronic LPS inhalation.
airway remodeling; lung inflammation; transforming growth factor- 1; matrix metalloproteinase-9; plasminogen activator inhibitor
Address for reprint requests and other correspondence: J. D. Savov, Duke Univ. Medical Center, P. O. Box 2629, Durham, NC 27710 (E-mail: jsavov{at}duke.edu ).
Abstract
Members of the genus Corynebacterium are increasingly recognized as causes of opportunistic infection; some species can be multidrug resistant, posing a treatment challenge. Daptomycin is ...frequently used as therapy of last resort in this setting, but previous work from our group demonstrated the ability of C striatum clinical isolates to rapidly develop high-level resistance to daptomycin, both in vivo and in vitro. Here, our objective was to expand this investigation into a multicenter study evaluating multiple Corynebacterium species. Corynebacterium strains from three tertiary-care academic medical centers (total, n = 76; site 1, n = 44; site 2, n = 15; site 3, n = 17) were evaluated, representing 16 species. Isolates were identified during routine clinical testing and reported to species level in accordance with each laboratory’s standard operating procedures. Identification of each species was confirmed using both VITEK MS and Bruker BioTyper MALDI-TOF MS. MICs to daptomycin (Etest), vancomycin (Etest), and telavancin (Liofilchem) at baseline were determined using gradient diffusion methods on Mueller-Hinton agar with blood (Hardy Diagnostics). Each isolate was then inoculated in duplicate to 5 mL Tryptic Soy Broth. A daptomycin Etest was submerged in one tube from each pair, and growth was observed after 24-hour incubation. If turbidity was observed in the tube with daptomycin, MICs for each of the 3 antimicrobials were reassessed. High-level daptomycin resistance emerged in 24 strains: C aurimucosum (1/1 isolate tested), C bovis (1/2), C jeikeium (2/11), C macginleyi (3/3), C resistens (1/1), C simulans (1/1), C striatum (14/14 isolates), and C ulcerans (1/1). The majority of these isolates had MIC values >256 µg/mL following exposure to daptomycin. Forty-eight other isolates remained susceptible to daptomycin: C afermentans (1/1), C amycolatum (19/20), C diphtheriae (1/1), C jeikeium (7/11), C kroppenstedtii (2/2), C propinquum (3/3), C pseudodiphtheriticum (6/6), C tuberculostearicum (0/6), and C urealyticum (0/3). Many of these isolates did not undergo MIC testing postdaptomycin exposure in broth due to complete lack of growth. Among those that did (n = 19), the median daptomycin MIC was 0.38 µg/mL (mean 0.42 µg/mL; range 0.023-1.0 µg/mL). One isolate of C bovis and two isolates of C jeikeium yielded variable susceptibility to daptomycin; a subset of resistant colonies grew adjacent to the gradient diffusion strip. Upon isolation and further MIC testing, these colonies maintained high-level resistance. In addition, one isolate of C amycolatum exhibited high-level daptomycin resistance (MIC >256 µg/mL) prior to in vitro exposure. All isolates in the cohort were susceptible to vancomycin and telavancin, both before and after daptomycin exposure. Our findings suggest that multiple Corynebacterium species can rapidly develop high-level daptomycin resistance after a short period of exposure to this antimicrobial. This finding has important clinical implications, especially in the treatment of invasive infections or infections of indwelling medical devices.
Introduction:Blood cultures are often obtained from healthy paediatric patients with fever on presentation to the emergency department (ED). Although published guidelines and previous research ...outlined indications for obtaining blood culture and the relatively low risk of bacteraemia in vaccinated children, there may be practice variability among institutions and physicians. Primary objective: To describe the demographic characteristics, diagnosis, disposition and outcome of children who are fully vaccinated, healthy and have fever from whom bacterial blood cultures were obtained. Secondary objective: To determine the rate of blood culture contamination and outcomes.Methods:Retrospective chart review of all blood cultures collected in the ED between January 1, 2015, and December 31, 2015. Patients aged 6 months to 17 years were eligible for enrolment. Children not fully vaccinated, immunocompromised or with chronic, debilitating disease were excluded. Patients were divided into febrile and afebrile cohorts based on the initial temperature at ED presentation. Data were analysed with two-sample t-test and chisquared analysis.Results:Blood cultures were obtained from 7.980 children at the ED, with an overall positivity rate of 5.51%. No significant difference was detected in the number of positive blood cultures between the two cohorts (p=0.85). No significant difference was found between pathogenic cultures between the two cohorts (p=0.35). All patients who were discharged with a positive blood culture were called back for a repeat culture. None grew a pathogenic organism on the repeat culture. The overall positive blood culture rate for true pathogens was 1.3%, and the overall contamination rate was 1.9%.Conclusion:The rates of positive blood culture between febrile and afebrile cohorts presenting to the ED were comparable. While the overall rate of positive culture remains low, consistent with previously reported rates of bacteraemia, an unacceptably high rate of contamination resulting in return visits was observed. Routine blood culture in children who were fully immunised and had a history of febrile illness is not indicated.
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