The Relationship between Inhibition of Cell Wall Synthesis and Bacterial Lethality

Shockman, Gérald D.; Daneo-Moore, L; McDowell, T D; Wong, William

doi:10.1016/b978-0-12-506303-6.50011-x

Cited by 9 publications

(9 citation statements)

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“…It is clear, however, that a diverse group of bacteria which are sensitive to penicillin do not lyse, even after prolonged exposure to high concentrations of the drug (3,19,23). These nonlytic phenotypes can be grouped into two categories: tolerant strains, which are growth inhibited but lose viability slowly (3,6,19,23), and nonlytic-death strains, which die rapidly after treatment with relatively low doses of, for example, benzylpenicillin (penicillin G). Both classes of nonlytic phenotypes fail to express autolytic activities.…”

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confidence: 99%

“…The secondary events are species dependent and can be related to growth rate (2) and medium composition (10). The widely accepted mechanism of penicillin-induced killing is that inhibition of synthesis results in a deregulation of the endogenous PG hydrolases (autolysins), which leads to the destruction of the structural integrity of the PG and ultimately death (23,26). It is clear, however, that a diverse group of bacteria which are sensitive to penicillin do not lyse, even after prolonged exposure to high concentrations of the drug (3,19,23).…”

mentioning

confidence: 99%

“…The widely accepted mechanism of penicillin-induced killing is that inhibition of synthesis results in a deregulation of the endogenous PG hydrolases (autolysins), which leads to the destruction of the structural integrity of the PG and ultimately death (23,26). It is clear, however, that a diverse group of bacteria which are sensitive to penicillin do not lyse, even after prolonged exposure to high concentrations of the drug (3,19,23). These nonlytic phenotypes can be grouped into two categories: tolerant strains, which are growth inhibited but lose viability slowly (3,6,19,23), and nonlytic-death strains, which die rapidly after treatment with relatively low doses of, for example, benzylpenicillin (penicillin G).…”

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confidence: 99%

“…Simultaneous treatment with penicillin G and either chloramphenicol or rifampin resulted in reduced levels of killing and the complete inhibition of RNA loss. These findings define a new mechanism of penicillin G-induced killing in the absence of cell wall disruption and suggest a basis for drug-induced antagonism of penicillin G-mediated nonlytic death.A unified model for the action of inhibitors of cell wall synthesis (23,26) predicts that in all susceptible bacteria, cell wall antibiotics act by inhibiting the assembly of insoluble peptidoglycan (PG), leading to bacteriostasis. The secondary events are species dependent and can be related to growth rate (2) and medium composition (10).…”

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confidence: 99%

“…A unified model for the action of inhibitors of cell wall synthesis (23,26) predicts that in all susceptible bacteria, cell wall antibiotics act by inhibiting the assembly of insoluble peptidoglycan (PG), leading to bacteriostasis. The secondary events are species dependent and can be related to growth rate (2) and medium composition (10).…”

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Mechanism of penicillin killing in the absence of bacterial lysis

McDowell

Reed

1989

Antimicrob Agents Chemother

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Exposure of group A streptococci (a nonlytic-death phenotype) to benzylpenicillin (penicillin G) produced a dose-dependent, rapid, and extensive hydrolysis of total cellular RNA, with the subsequent loss of hydrolysis products from the cell. This loss of RNA correlated well with loss of viability and was not accompanied by solubilization of the cell wall or comparable losses of either protein or DNA. Simultaneous treatment with penicillin G and either chloramphenicol or rifampin resulted in reduced levels of killing and the complete inhibition of RNA loss. These findings define a new mechanism of penicillin G-induced killing in the absence of cell wall disruption and suggest a basis for drug-induced antagonism of penicillin G-mediated nonlytic death.A unified model for the action of inhibitors of cell wall synthesis (23,26) predicts that in all susceptible bacteria, cell wall antibiotics act by inhibiting the assembly of insoluble peptidoglycan (PG), leading to bacteriostasis. The secondary events are species dependent and can be related to growth rate (2) and medium composition (10). The widely accepted mechanism of penicillin-induced killing is that inhibition of synthesis results in a deregulation of the endogenous PG hydrolases (autolysins), which leads to the destruction of the structural integrity of the PG and ultimately death (23,26). It is clear, however, that a diverse group of bacteria which are sensitive to penicillin do not lyse, even after prolonged exposure to high concentrations of the drug (3,19,23). These nonlytic phenotypes can be grouped into two categories: tolerant strains, which are growth inhibited but lose viability slowly (3,6,19,23), and nonlytic-death strains, which die rapidly after treatment with relatively low doses of, for example, benzylpenicillin (penicillin G). Both classes of nonlytic phenotypes fail to express autolytic activities.A previously proposed mechanism for nonlytic death predicted that partial hydrolysis of the PG fabric (nicking) would be sufficient to alter the essential structural features of the cell wall and would lead to death (3). However, we were unable to find evidence to support this hypothesis (15).In this report, we describe results of studies of penicillininduced nonlytic death in group A streptococcus. Our findings clearly demonstrate that penicillin G induces a rapid, dose-dependent, specific loss of total cellular RNA in the absence of hydrolysis of the cell wall. In addition, we present evidence which suggests that the antagonistic effects of inhibitors of transcription or ribosomal function are associated with impairment of penicillin G-induced RNA hydrolysis. These observations define a mechanism of penicillin G action which can account for the bactericidal nature of the drug in the absence of cellular dissolution. MATERIALS AND METHODSOrganisms and growth conditions. Group A streptococcus strain 1224 was a clinical isolate obtained from St. Christopher's Hospital for Children, Philadelphia, Pa. Enterococcus hirae ATCC 9790 (Streptococcus faecium)...

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Mechanism of penicillin killing in the absence of bacterial lysis

McDowell

Reed

1989

Antimicrob Agents Chemother

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Cephalosporins

Roberts¹

2000

Kirk-Othmer Encyclopedia of Chemical Technology

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CEPHALOSPORINSThe cephalosporins, a subgroup of β-lactam antibiotics, consist of a 4-membered lactam ring fused through the nitrogen and the adjacent tetrahedral carbon atom to a second heterocycle forming a 6-membered dihydrothiazine ring. Other structural features common to all the cephalosporins are a carboxyl group on the dihydrothiazine ring on the carbon next to the ring nitrogen and a functionalized amino group on C-7, the carbon of the β-lactam ring opposite the nitrogen. These features are evidenced in 7-aminocephalosporanic acid [957-68-6] (7-ACA), C 10 H 12 N 2 O 5 S 1. Cephalosporins, like all β-lactam antibiotics, exert their antibacterial effect by interfering with the synthesis of the bacterial cell wall. These antibiotics tend to be "irreversible" inhibitors of cell wall biosynthesis and they are usually bactericidal at concentrations close to their bacteriostatic levels. Cephalosporins are widely used for treating bacterial infections. They are highly effective antibiotics and have low toxicity.

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