gram-negative

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gram-negative

 [gram-neg´ah-tiv]
losing the stain or decolorized by alcohol in Gram's method of staining; see Gram stain. This is a primary characteristic of bacteria having a cell wall composed of a thin layer of peptidoglycan covered by an outer membrane of lipoprotein and lipopolysaccharide.

gram-neg·a·tive

(gram-neg'ă-tiv), In this expression gram begins with lowercase g but Gram stain takes an uppercase G.
Refers to the inability of a type of bacterium to resist decolorization with alcohol after being treated with crystal violet. However, following decolorization, these bacteria can be readily counterstained with safranin, imparting a pink or red color to them when viewed by light microscopy. This reaction is usually an indication that the outer structure of the bacterium consists of a cytoplasmic (inner) membrane surrounded by a relatively thin peptidoglycan layer, which in turn is surrounded by an outer membrane. See: Gram stain.

gram-negative

or

Gram-negative

(grăm′nĕg′ə-tĭv)
adj.
Of, relating to, or being a bacterium that does not retain the violet stain used in the Gram stain method.

gram-neg·a·tive

(gram-neg'ă-tiv)
Refers to the inability of a bacterium to resist decolorization with alcohol after being treated with Gram crystal violet. However, following decolorization, these bacteria can be readily counterstained with safranin, imparting a pink or red color to the bacterium when viewed by light microscopy.
See: Gram stain

Gram-negative

see GRAM'S STAIN.

Gram-negative

Refers to the property of many bacteria that causes them to not take up color with Gram's stain, a method which is used to identify bacteria. Gram-positive bacteria which take up the stain turn purple, while Gram-negative bacteria which do not take up the stain turn red.

gram-neg·a·tive

(gram-neg'ă-tiv)
Refers to the inability of a type of bacterium to resist decolorization with alcohol after being treated with crystal violet.
References in periodicals archive ?
Among the Gram-negative bacilli, most of the isolates were sensitive to piperacillin + tazobactam followed by amikacin and imipenem.
Table 2--Bacteremia in patients with pressure ulcers colonized by Gram-negative bacilli. Infected pressure Non-infected p-value (a) ulcer pressure ulcer N = 16(%) N = 34(%) Bacteremia 10(62.5) 20(58.8) 0.80 Concordance 6(60.0) 5(25.0) 0.10 Death 8(80.0) 7(35.0) 0.04 OR (b) (95% CI) Bacteremia 1.17 (0.34-3.96) Concordance 4.50 (0.89-22.75) Death 7.43 (1.23-45.0) (a) Statistical significance at 5%.
The rate of resistance to carbapenem among Gram-negative bacilli seen in our institution could possibly be due to the fact that this is a reference center, and that many of the patients had prior contact with other healthcare institutions and history of antibiotic use.
2,452 of the positive bottles grew Gram-negative Bacilli. We excluded 2,054 repeat positives from the same collection time, 276 bottles which did not undergo direct susceptibility testing, 18 patients who were discharged home before results were released, 11 bottles with mixed growth, and 4 patients with missing treatment data, leaving a total of 89 eligible blood cultures in our analysis (Figure 1).
Infections with MDR gram-negative bacilli have been reported to be associated with poor outcomes.23 But in the current study MDR E.coli bacteraemia was not a predictor of mortality, when evaluated in a multivariable analysis, despite the fact that there were more deaths in this group of patients.
Rapid identification and susceptibility testing of Gram-negative bacilli from blood cultures using the Vitek.
Finally, Gram stain and final culture results were recorded as one or more morphologic types that included gram-positive cocci, gram-positive bacilli, gram-negative cocci, gram-negative bacilli, and fungi.
Ventilator-associated pneumonia (VAP) is one of the most common and severe hospital-adquired infections, and multidrugresistant gram-negative bacilli (MDR-GNB) constitute the main etiology in many countries.
Other agents such as macrolides and lincosamides linezolid and vancomycin have excellent activity against Grampositive cocci while demonstrating minimal activity against Gram-negative bacilli [2].
Alexander McAdam: Compared to MRSA or VRE, we know little about the best methods for ASC for multidrug-resistant gram-negative bacilli. It is important to understand this limitation when deciding whether and how to screen for multidrug-resistant gram-negative bacilli.
DENVER -- Penicillin allergies are no reason to forego empiric beta-lactam therapy in patients whose blood is infected with gram-negative bacilli, according to results from a retrospective study.
As a result of increasing antibiotic resistance to several types of gram-negative bacilli, the Centers for Disease Control and Prevention has also set up the Multi-Site Resistant Gram-Negative Bacilli Surveillance Initiative (MuGSI) to track infections due to carbapenem-resistant organisms including E.

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