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

/gram-neg·a·tive/ (-neg´ah-tiv) losing the stain or decolorized by alcohol in Gram's method of staining, characteristic of bacteria having a cell wall surface more complex in chemical composition than the gram-positive bacteria.

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-negative

Etymology: Hans C.J. Gram, Danish physician, 1853-1938; L, negare, to say no
having the pink color of the counterstain used in Gram's method of staining microorganisms. This property is a primary method of characterizing organisms in microbiology. Some of the most common gram-negative pathogenic bacteria are Bacteroides fragilis, Brucella abortus, Escherichia coli, Haemophilus influenzae, Klebsiella pneumoniae, Neisseria gonorrhoeae, Proteus vulgaris, Pseudomonas aeruginosa, Salmonella typhi, Shigella dysenteriae, and Yersinia pestis.

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.

gram-negative,

n having the pink color of the counterstain used in Gram's method of staining microorganisms. Staining property is a common method of classifying bacteria. See also Gram's stain.

gram-negative

said of bacteria that are decolorized by alcohol in Gram's method of staining (see gram's stain), and are thus stained only with the counter stain (usually red). Gram-negative bacteria have a much thinner layer of peptidoglycan in the cell wall than Gram-positive bacteria.
References in periodicals archive ?
Small Molecules for Bacterial Infections, Small Molecules for Escherichia Coli Infections,Small Molecules for Multi-Drug Resistant Gram-Positive and Gram-Negative Bacterial Infections, Small Molecules to Inhibit 23S Ribosomal RNA for Infections, Small Molecules to Inhibit 30S RNA, Topoisomerases II and IV for Bacterial Infections, Small Molecules to Inhibit RecA for Bacterial Infections, Synthetic Peptide for Oncology and Infectious Disease, Synthetic Peptide to Antagonize TLR-4 for Oncology, Immunology and Infectious Disease and Synthetic Peptides for Escherichia Coli Infections.
A review of the Gram-Negative Bacterial Infections products under development by companies and universities/research institutes based on information derived from company and industry-specific sources.
We are pleased that the data from this Phase 2 trial support plazomicin's potential utility as an important new treatment option for patients with certain serious Gram-negative bacterial infections," said Kenneth J.
CXA-201 is currently being studied in pivotal Phase 3 trials as a first-line intravenous therapy for the treatment of complicated intra-abdominal infections and complicated urinary tract infections caused by Gram-negative bacterial infections, including those caused by multi-drug resistant Pseudomonas aeruginosa.
These factors include the following: (i) CXA-201 may not show sufficient therapeutic effect or an acceptable safety profile in clinical trials; (ii) CXA-201 may not act in the way expected based on prior clinical and pre-clinical trials of CXA-101 and CXA-201; (iii) clinical trials of CXA-201 may not be successful or conducted in a timely manner; (iv) the commercial market for the use of CXA-201 for the treatment of certain Gram-negative bacterial infections may not be as large as Cubist anticipates; (iv) others may develop technologies or products superior to CXA-201 for the treatment of certain Gram-negative bacterial infections; (v) technical difficulties or excessive costs relating to the manufacture of CXA-201; (vi) Cubist or Astellas Pharma Inc.
This use of the iron uptake system may allow S-649266 to be an effective approach to treat Gram-negative bacterial infections that are not able to be treated by available antibiotics.
1 Driver: Increase in the Incidence of MDR Gram-Negative Bacterial Infections 14 3.
They are resistant to nearly all antibiotics including carbapenems, a broad spectrum class of antibiotics considered to be the last resort for serious gram-negative bacterial infections.
Steve Gilman, PhD, Cubist's Chief Scientific Officer, said, "We are pleased with the safety and microbiological response data from this study, which we believe supports the further development of CXA-201 as a useful therapeutic agent for the treatment of certain serious Gram-negative bacterial infections.
CXA-201 is being developed as a first-line intravenous therapy for the treatment of certain serious Gram-negative bacterial infections in the hospital, including those caused by multi-drug resistant P.
Multidrug-resistant Gram-negative bacterial infections are an area of significant unmet medical need, particularly in acute care settings.
Four studies demonstrating the activity of MK-2764 against resistant and atypical bacteria and tissue-based pharmacokinetic/pharmacodynamic studies of Gram-positive and Gram-negative bacterial infections were presented at the 46th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in San Francisco, CA.

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