The Antibacterial Effects of Low Concentrations of Antibiotics

Chopra, Ian; Linton, A. H.

doi:10.1016/s0065-2911(08)60240-4

Cited by 38 publications

(23 citation statements)

References 181 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is well known that subMICs may affect bacterial morphology. Exposure of Gram-positive organisms to low concentrations of p-lactam antibiotics usually results in the formation of abnormally large cells with thickened cross walls, but morphologically normal outer walls (Chopra & Linton, 1986;Lorian, 1980). Some Gram-negative bacilli, such as Proteus mirabilis, when exposed to penicillin, as well as to other agents, elongate and eventually produce long filaments (Atkinson & Amaral, 1982;Lorian, 1980).…”

Section: Resultsmentioning

confidence: 99%

“…Some Gram-negative bacilli, such as Proteus mirabilis, when exposed to penicillin, as well as to other agents, elongate and eventually produce long filaments (Atkinson & Amaral, 1982;Lorian, 1980). Filament formation appears to be the most common effect produced by P-lactam antibiotics at subMIC (Chopra & Linton, 1986). These morphological alterations tend to be characteristic for specific P-lactam antibiotics and are related to the affinity of the antibiotics for particular penicillin-binding proteins (PBPs).…”

Section: Resultsmentioning

confidence: 99%

“…Some of these effects are morphological changes (Atkinson & Amaral, 1982;Chopra & Linton, 1986;Lorian, 1980;Lorian & Ernst, 1987), reduction of growth (Atkinson & Amaral, 1982;Washington, 1979), inhibition of enzyme or toxin production (Shibl, 1983), loss of adhesive properties (Schifferli & Beachey, 1988a, b;Shibl, 1985), and susceptibility to host humoral and cellular defences (Chopra & Linton, 1986). These effects are usually observed when bacteria are incubated with antibiotics at levels below the MIC or subminimal inhibitory concentrations (subMICs).…”

Section: -6857 O 1991 Sgmmentioning

confidence: 99%

See 2 more Smart Citations

Effects of antibiotics on the growth and morphology of Pasteurella multocida

Jacques

Lebrun

Foiry

et al. 1991

Journal of General Microbiology

View full text Add to dashboard Cite

The effects of subminimal inhibitory concentrations (subMICs) of certain antibiotics, namely penicillin G, tetracycline and trimethoprim/sulphamethoxazole, on the growth and morphology of Pasteurella multocida were evaluated. SubMICs of penicillin markedly reduced the growth of P. multocida. Tetracycline and trimethoprim/ sulphamethoxazole had no effect on its growth. SubMICs of penicillin greatly affected the morphology of P. multocida. At the highest concentrations tested (1/2 and 1/4 MIC) cells were acapsulate, and long filamentous cells (4-6 pm) were observed with some isolates. There was no correlation between the observed differences in the penicillin-binding proteins of the P. multocida isolates, and the extent of cell filamentation induced by penicillin G. SubMICs of tetracycline and trimethoprim/sulphamethoxazole did not seem to affect capsule production although filamentation was observed. Our results indicate that subMICs of penicillin can reduce growth of P. multocida. Furthermore, results also indicate that subMICs of antibiotics can affect the production of capsular material and the morphology of P. multocida.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: -6857 O 1991 Sgmmentioning

confidence: 99%

See 1 more Smart Citation

Effects of antibiotics on the growth and morphology of Pasteurella multocida

Jacques

Lebrun

Foiry

et al. 1991

Journal of General Microbiology

View full text Add to dashboard Cite

show abstract

“…These include bacterial synthesis of the cell wall and extracellular products, bacterial adherence to cells, and changes in bacterial morphology [21,22]. SubMIC EM reduces PA adherence to acid-injured murine tracheal mucosa [23], PA ciliotoxin, haemagglutinin and protease production [24,25], neutrophil migration [26], and superoxide generation [26].…”

Section: Discussionmentioning

confidence: 99%

Effects of erythromycin onPseudomonas aeruginosaadherence to collagen and morphologyin vitro

Tsang¹,

Ng²,

Ho³

et al. 2003

Eur Respir J

View full text Add to dashboard Cite

The airways of patients with bronchiectasis and cystic fibrosis are often chronically colonised by Pseudomonas aeruginosa (PA), which is virtually impossible to eradicate. Low-dose erythromycin (EM), for unknown mechanisms, is efficacious in bronchiectasis and diffuse panbronchiolitis.In this study, an in vitro model to investigate PA adherence to human type IV basement collagen was developed by using scanning electron microscopy (SEM). There were significantly less PA bacilli per 20 random SEM fields (4,0006) when PA was cultured in 0.05, 0.5 and 5 mg?mL -1 of EM compared with control (absence of EM). Adherence density (20 SEM fields?log -1 inocular size) for PA obtained from no EM (56.8¡43.16) was significantly higher than that obtained from 0.05, 0.5, and 5 mg?mL -1 EM (21.5¡17.56, 23.3¡16.65, and 21.4¡12.65 respectively). By using SEM it was found that PA, when incubated in EM (0.05, 0.5, 5 mg?mL -1 ) had a significant reduction in its diagonal length, radius, height, volume and surface area.It is possible, therefore, that these misshaped Pseudomonas aeruginosa bacilli are more susceptible to host defence mechanisms, while at the same time less adherent to the basement membrane of the airway in vivo. Therefore, this could help explain the clinical efficacy of low-dose erythromycin therapy on patients with Pseudomonas aeruginosa infection. Eur Respir J 2003; 21: 401-406.

show abstract

“…PAE can also affect bacteria in other ways;2 some of these effects include changes in growth kinetic^,^ morphology,* inhibition of enzyme and toxin prod~c t i o n ,~ loss of adhesive properties6y ' and susceptibility to host humoral and cellular immunity. 8 In other studies, these effects were usually observed when bacteria were incubated with antibiotics at levels below the MIC (sub-MIC). During PAE, bacterial physiology may also be affected by exposure to the antimicrobial agents.…”

Section: Introductionmentioning

confidence: 97%

Post-antibiotic effect of azithromycin and erythromycin on streptococcal susceptibility to phagocytosis

Ramadan

Tawfik

Shibl

et al. 1995

Journal of Medical Microbiology

View full text Add to dashboard Cite

Summary. The effect of azithromycin and erythromycin on growth, cell surface hydrophobicity and the susceptibility to the bactericidal activity of human polymorphonuclear leucocytes (PMNL) was examined in four Streptococcus species. Exposure to either 10 x MIC azithromycin or erythromycin induced a post-antibiotic effect (PAE) of between 2.4 and 4.3 h. Erythromycin caused a longer PAE for S. sanguis than azithromycin under the same conditions. The cell surface charge (hydrophobic or hydrophilic) of the streptococci was altered significantly during PAE ; loss of hydrophobicity was induced by both macrolides, and this effect was variable amongst the species. The decrease in hydrophobicity was not related to inhibition of growth. The effect of each drug during PAE on the interaction of opsonised suspensions of the streptococci with human PMNL revealed that erythromycin, and to a lesser extent azithromycin, increased susceptibility to the bactericidal activity of human PMNL; this effect was abolished following PAE. The present study clearly showed that PAE should not only be considered as delayed bacterial growth, but also as modulation of bacterial susceptibility to phagocytosis which may influence the outcome of the host-parasite relationship.

show abstract

The Antibacterial Effects of Low Concentrations of Antibiotics

Cited by 38 publications

References 181 publications

Effects of antibiotics on the growth and morphology of Pasteurella multocida

Effects of antibiotics on the growth and morphology of Pasteurella multocida

Effects of erythromycin onPseudomonas aeruginosaadherence to collagen and morphologyin vitro

Post-antibiotic effect of azithromycin and erythromycin on streptococcal susceptibility to phagocytosis

Contact Info

Product

Resources

About