Gram-positive

• gram-positive

From Gram (“a surname”) + positive, after Danish bacteriologist Hans Christian Gram, who invented the Gram staining method.

Gram-positive (not comparable)

1. (bacteriology, of a bacterium) That stains dark blue or violet after Gram staining, due to large quantities of peptidoglycan in the cell wall.
   • 1997, T. G. Nagaraja, C. J. Newbold, C. J. Van Nevel, D. I. Demeyer, “13: Manipulation of ruminal fermentation”, in P. N. Hobson, C. S. Stewart, editors, The Rumen Microbial Ecosystem, 2nd edition, page 545:

     Generally, ionophore antibiotics are highly effective against Gram-positive bacteria but exhibit little or no activity against Gram-negative bacteria (Chen and Wolin, 1979; Watanabe et al., 1981).

   • 2007, Alan R. Hauser, Antibiotic Basics for Clinicians: Choosing the Right Antibacterial Agent‎, page 201:

     Note that L.^[Listeria] monocytogenes is one of the few Gram-positive bacteria against which vancomycin is not effective — hence the need for ampicillin.

   • 2011, Patricia L. Keen, Mark H. M. M. Montforts, Antimicrobial Resistance in the Environment, page 108:

     The majority of Gram-positive (82%) and Gram-negative (64%) genera carry either ribosomal protection genes alone or in combination with efflux/enzymatic genes as illustrated in Table 7.2.

• Gram-negative

• Gram staining
• Gram's method