THE <i>IN VITRO</i> ACTIVITY OF GENTAMICIN, TOBRAMYCIN AND NETILMICIN AGAINST 500 CLINICAL ISOLATES OF BACTERIA

Digranes, Asbjørn; Dibb, William L.; Benonisen, Eva; Ostervold, B

doi:10.1111/j.1699-0463.1983.tb00022.x

Cited by 6 publications

(4 citation statements)

References 10 publications

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“…2 ). Different composition of media is reported to change the activity of antibiotics [ 44 – 46 ]. The Ca 2+ and Mg 2+ ions in CaMHB media are required for a correct antimicrobial susceptibility testing because those ions reflect the divalent cation concentration in human blood [ 43 , 47 – 49 ].…”

Section: Discussionmentioning

confidence: 99%

Influence of biofilm growth age, media, antibiotic concentration and exposure time on Staphylococcus aureus and Pseudomonas aeruginosa biofilm removal in vitro

Chen

Thomsen

Winkler³

et al. 2020

BMC Microbiol

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Background: Biofilm is known to be tolerant towards antibiotics and difficult to eradicate. Numerous studies have reported minimum biofilm eradication concentration (MBEC) values of antibiotics for many known biofilm pathogens. However, the experimental parameters applied in these studies differ considerably, and often the rationale behind the experimental design are not well described. This makes it difficult to compare the findings. To demonstrate the importance of experimental parameters, we investigated the influence of biofilm growth age, antibiotic concentration and treatment duration, and growth media on biofilm eradication. Additionally, OSTEOmycin™, a clinically used antibiotic containing allograft bone product, was tested for antibiofilm efficacy. Results: The commonly used Calgary biofilm device was used to grow 24 h and 72 h biofilms of Staphylococcus aureus and Pseudomonas aeruginosa, which were treated with time-dependent vancomycin (up to 3000 mg L − 1) and concentration-dependent tobramycin (up to 80 mg L − 1), respectively. Two common bacteriological growth media, tryptic soy broth (TSB) and cation-adjusted Mueller Hinton broth (CaMHB), were tested. We found for both species that biofilms were more difficult to kill in TSB than in CaMHB. Furthermore, young biofilms (24 h) were easier to eradicate than old biofilms (72 h). In agreement with vancomycin being time-dependent, extension of the vancomycin exposure increased killing of S. aureus biofilms. Tobramycin treatment of 24 h P. aeruginosa biofilms was found concentration-dependent and time-independent, however, increasing killing was indicated for 72 h P. aeruginosa biofilms. Treatment with tobramycin containing OSTEOmycin T™ removed 72 h and 168 h P. aeruginosa biofilms after 1 day treatment, while few 72 h S. aureus biofilms survived after 2 days treatment with vancomycin containing OSTEOmycin V™. Conclusions: This study demonstrated biofilm removal efficacy was influenced by media, biofilm age and antibiotic concentration and treatment duration. It is therefore necessary to taking these parameters into consideration when designing experiments. The results of OSTEOmycin™ products indicated that simple in vitro biofilm test could be used for initial screening of antibiofilm products. For clinical application, a more clinically relevant biofilm model for the specific biofilm infection in question should be developed to guide the amount of antibiotics used for local antibiofilm treatment.

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Section: Discussionmentioning

confidence: 99%

Influence of biofilm growth age, media, antibiotic concentration and exposure time on Staphylococcus aureus and Pseudomonas aeruginosa biofilm removal in vitro

Chen

Thomsen

Winkler³

et al. 2020

BMC Microbiol

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“…Biofilm eradication was found different with the two media (Figure 1 and Figure 2). Different composition of media is reported to change the activity of antibiotics (27)(28)(29). The Ca 2+ and Mg 2+ ions in CaMHB media are required for a correct antimicrobial susceptibility testing because those ions reflect the divalent cation concentration in human blood (30)(31)(32)(33).…”

Section: Growth Mediamentioning

confidence: 99%

Influence of biofilm growth age, media and antibiotics exposure time on Staphylococcus aureus and Pseudomonas aeruginosa biofilm removal in vitro

Chen¹,

Xu²,

Winkler³

et al. 2020

Preprint

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Biofilm is known to be tolerant towards antibiotics and difficult to eradicate. Numerous studies have reported Minimum Biofilm Eradication Concentration (MBEC) values of antibiotics for many known biofilm pathogens. However, the experimental parameters applied in these studies differ considerably, and often the rationale behind the experimental design are not well described. This makes it difficult to compare the findings. To demonstrate the importance of experimental parameters, we investigated the influence of biofilm growth age, antibiotic treatment duration and growth media on biofilm eradication in this study. The commonly used biofilm model Calgary biofilm device was used to grow 24 h and 72 h biofilms of Staphylococcus aureus and Pseudomonas aeruginosa , which were treated with time-dependent vancomycin and concentration-dependent tobramycin, respectively. Two common bacteriological growth media Tryptic Soy Broth (TSB) and Cation-adjusted Mueller Hinton Broth (CaMHB) were tested. We found for both species that biofilms were more difficult to kill in TSB than in CaMHB. Furthermore, young biofilms (24 h) were easier to eradicate than old biofilms (72 h). In agreement with vancomycin being time-dependent, extension of the vancomycin exposure increased killing of S. aureus biofilms. Tobramycin treatment of 24 h P. aeruginosa biofilms was found concentration-dependent and time-independent, however, increasing killing was indicated for 72 h P. aeruginosa biofilms. This study demonstrated biofilm removal efficacy was influenced by media, biofilm age and antibiotics treatment duration. It is therefore necessary to taking these parameters into consideration when designing experiments.

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“…The differences in MIC values obtained between DMEM and other media indicate a considerable influence of the culture medium on the inhibitory activity of antibiotics. It is reported that different media compositions affect antibiotic activity [ 63 , 64 ]. We assume that nutrients provided in culture media not only impact the bacterial metabolic activity but also interfere with the antimicrobial agents, changing their efficacy.…”

Section: Discussionmentioning

confidence: 99%

The Medium Composition Impacts Staphylococcus aureus Biofilm Formation and Susceptibility to Antibiotics Applied in the Treatment of Bone Infections

Paleczny

Brożyna

Dudek-Wicher

et al. 2022

IJMS

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The biofilm-associated infections of bones are life-threatening diseases, requiring application of dedicated antibiotics in order to counteract the tissue damage and spread of microorganisms. The in vitro analyses on biofilm formation and susceptibility to antibiotics are frequently carried out using methods that do not reflect conditions at the site of infection. To evaluate the influence of nutrient accessibility on Staphylococcus aureus biofilm development in vitro, a cohesive set of analyses in three different compositional media was performed. Next, the efficacy of four antibiotics used in bone infection treatment, including gentamycin, ciprofloxacin, levofloxacin, and vancomycin, against staphylococcal biofilm, was also assessed. The results show a significant reduction in the ability of biofilm to grow in a medium containing elements occurring in the serum, which also translated into the diversified changes in the efficacy of used antibiotics, compared to the setting in which conventional media were applied. The differences indicate the need for implementation of adequate in vitro models that closely mimic the infection site. The results of the present research may be considered an essential step toward the development of in vitro analyses aiming to accurately indicate the most suitable antibiotic to be applied against biofilm-related infections of bones.

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THE IN VITRO ACTIVITY OF GENTAMICIN, TOBRAMYCIN AND NETILMICIN AGAINST 500 CLINICAL ISOLATES OF BACTERIA

Cited by 6 publications

References 10 publications

Influence of biofilm growth age, media, antibiotic concentration and exposure time on Staphylococcus aureus and Pseudomonas aeruginosa biofilm removal in vitro

Influence of biofilm growth age, media, antibiotic concentration and exposure time on Staphylococcus aureus and Pseudomonas aeruginosa biofilm removal in vitro

Influence of biofilm growth age, media and antibiotics exposure time on Staphylococcus aureus and Pseudomonas aeruginosa biofilm removal in vitro

The Medium Composition Impacts Staphylococcus aureus Biofilm Formation and Susceptibility to Antibiotics Applied in the Treatment of Bone Infections

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