Gram negative


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Gram negative

Used of a micro-organism that when stained by Gram's method does not retain the purplish dye, methyl violet, but only the red counter-stain carbol fuchsin. Stained Gram negative organisms appear red. The whole class of medically important bacteria can be divided into a large GRAM POSITIVE group and a smaller Gram negative group. This division is an important step in identification. (Hans Christian Joachim Gram, 1853–1938, Danish physician).
References in periodicals archive ?
[beta]-lactamase enzymes are the most frequent and play a key role, conferring resistance of bacteria to the [beta]-Lactam antibiotic group, such as penicillins and cephalosporins.14,15 Antibiotic resistances among Gram negative bacteria is on increase due to the spread of strains producing extended-spectrum [beta]-lactamase enzymes (ESBLs).
Over the previous couple of years, Metallo-beta-lactamase producing Gram Negative Rods are being notifiable with the increasing frequency from various parts of the world and they seems as a most generally circulated and have carbapenem resistance mechanism.
None of the Gram negative bacteria showed presence of the KPC gene but 7 Gram negative bacteria showed carbapenem resistance in antimicrobial susceptibility testing.
Antimicrobial susceptibility of Gram negative organisms isolated from patients hospitalized in intensive care units in United States and European hospitals (2009-2011).
ESBL test-ESBL production in gram negative isolates were confirmed by double disk potentiation test (phenotypic confirmatory test).
Keywords: Non fermenter Gram negative bacilli (NFGNB), Imipenem resistant, Metallo beta lactamase, Antimicrobial susceptibility.
Staphylococcus aureus was found to be the commonest organism (15, 27.27%), closely followed by Gram negative bacilli (14, 25.45%) (Table 2).
Isolation and identification: Gram negative bacteria were isolated and identified following Bergey's Manual of Determinative Bacteriology (1994).
Many studies done in CSOM have found the predominance of gram negatives in the ear discharge, with Pseudomonas and Proteus species as the most commonly identified aerobic organisms, while Bacteroides and Peptococcus/Peptostreptococcus sp.
Upon gram staining, 4 isolates were identified as gram positive bacteria, while the 12 isolates shown as gram negative bacteria.
Overall, 26 different organisms (12 gram positive, 12 gram negative, and two acid fast bacilli) were identified in patients with BSIs.
The genus Clostridium is a phylogenetically heterogeneous group of anaerobic, endospore-forming, rod-shaped bacteria; they are usually gram positive, but some species may stain gram variable or gram negative (1,2).