KINETICS OF THE ACTION OF AMPICILLIN ONESCHERICHIA COLI

Abstract

Seligman, Stephen J. (University of California, Los Angeles) and William L. Hewitt . Kinetics of the action of ampicillin on Escherichia coli . J. Bacteriol. 85: 1160–1164. 1963.—The curve of the number of viable Escherichia coli after exposure to ampicillin can be divided into three phases: a lag phase, a rapid bactericidal phase, and a slow bactericidal phase. Some of the variables affecting the magnitude of the first two of these phases were investigated. Progressive lowering of drug concentration resulted in prolongation of the lag phase and decrease in slope and extent of the rapid bactericidal phase. The production of elongated gram-negative forms and the emergence of a mutant with increased penicillinase activity complicated interpretation of the lower dose curves. With sufficient drug concentration, the length of the lag phase and the slope of the rapid bactericidal curve were independent of the size of inoculum up to 10 8 organisms. Varying pH revealed that maximal activity, as measured by the shortest lag phase and steepest slope of the rapid bactericidal phase, was present at slightly acid pH levels. Increasing pH resulted principally in prolongation of lag phase. With greater acidity, decrease in slope of the rapid bactericidal phase was more prominent. Cultures studied under conditions of lessened metabolic activity exhibited prolonged lag phase and decreased slope and extent of rapid bactericidal phase.

Spatial segregation and cooperation in radially expanding microbial colonies under antibiotic stress

“…Our results suggest that the protective effects of resistant cells can be relatively long-range, extending many times the size of a single cell. Such long-range protection is expected in well-stirred communities without spatial constraints [ 35 , 38 , 39 , 42 ] and is commonly observed on agar plates [ 50 ], especially when cells secrete the enzyme into the extracellular space. On the other hand, the protective effects of drug degrading enzymes appear considerably shorter-range in some naturally occurring isolates [ 45 ], where long-range protection may require alternative mechanisms such as persistence and may depend on whether drug degradation is intracellular [ 36 , 37 , 41 ].…”

“…Spatial structure can enhance or inhibit these effective intracellular interactions, creating an environment where co-operation, competition, and evolutionary selection are potentially shaped by spatial constraints [ 40 , 43 – 49 ]. For example, microbiologists have long reported the existence of “satellite” colonies [ 50 ], drug-sensitive populations that appear near enzyme-producing resistant colonies on agar plates, suggesting that resistance can be cooperative on scales of millimeters or more. Similarly, long-range effects have been recently measured for oxygen gradients in biofilms [ 51 ], yet metabolic gradients have been shown to be relatively short-ranged [ 52 ], and droplet-based printing techniques have shown that specific microscale structure determines dynamics in interacting colicin-producing strains [ 53 ].…”

Spatial segregation and cooperation in radially expanding microbial colonies under antibiotic stress

“…Our results suggest that the protective effects of resistant cells can be relatively long-range, extending for many times the size of a single cell. Such long-range protection is expected in well-stirred communities without spatial constraints (5, 68, 11, 70) and is commonly observed on agar plates (78), especially when cells secrete the enzyme into the extracellular space. On the other hand, the protective effects of drug degrading enzymes appear considerably shorter-range in some naturally occurring isolates (18), where long-range protection may require alternative mechanisms such as persistence, and may depend on whether drug degradation is intracellular (66, 67, 14).…”

“…Spatial structure can enhance or inhibit these effective intracellular interactions, creating an environment where cooperation, competition, and evolutionary selection are potentially shaped by spatial constraints (71, 69, 72, 18, 73, 74, 75, 76). For example, microbiologists have long reported the existence of (sometimes annoying (77)) “satellite” colonies (78), drug-sensitive populations that appear near enzyme-producing resistant colonies on agar plates, suggesting that resistance can be cooperative on scales of millimeters or more. Similarly long-range effects have been recently measured for oxygen gradients in biofilms (79), yet metabolic gradients have been shown to be relatively short-ranged (80), and droplet-based printing techniques have shown that specific microscale structure determines dynamics in interacting colicin-producing strains (81).…”

Ampicillin activates Mpk1 phosphorylation in Saccharomyces cerevisiaeand ERK1/2 phosphorylation in HepG2 cells

“…It is relatively nontoxic and effective against many gram-positive and gram-negative bacteria, including Streptococcus pneumoniae, Streptococcus pyogenes, Escherichia coli, Salmonella, and Neisseria meningitidis. Ampicillin belongs to the family of beta-lactam antibiotics that irreversibly inhibit the transpeptidase activity required for the synthesis of bacteria cell walls (Acred et al, 1962;Kennedy et al, 1963;Seligman et al, 1963;Campos et al, 1992;Lacy et al, 1999;WHO Young Infants Study Group, 1999).…”