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Characterization of Biofilm Formation in [Pasteurella] pneumotropica and [Actinobacillus] muris Isolates of Mouse Origin.

Sager M, Benten WP, Engelhardt E, Gougoula C, Benga L - PLoS ONE (2015)

Bottom Line: We demonstrate that both [P.] pneumotropica biotypes but not [A.] muris are able to form robust biofilms in vitro, a phenotype which is widely spread among the field isolates.Conversely, no effect or a decrease in the biofilm quantity was observed by biofilm dispersal using sodium periodate on further biotype Jawetz isolates, suggesting that polysaccharides might be incorporated in the biofilm structure.We additionally show that [P.] pneumotropica cells enclosed in biofilms were less sensitive to treatment with amoxicillin and enrofloxacin than planktonic bacteria.

View Article: PubMed Central - PubMed

Affiliation: Central Animal Research Facility, Heinrich-Heine-University, University Hospital, Düsseldorf, Germany.

ABSTRACT
[Pasteurella] pneumotropica biotypes Jawetz and Heyl and [Actinobacillus] muris are the most prevalent Pasteurellaceae species isolated from laboratory mouse. However, mechanisms contributing to their high prevalence such as the ability to form biofilms have not been studied yet. In the present investigation we analyze if these bacterial species can produce biofilms in vitro and investigate whether proteins, extracellular DNA and polysaccharides are involved in the biofilm formation and structure by inhibition and dispersal assays using proteinase K, DNase I and sodium periodate. Finally, the capacity of the biofilms to confer resistance to antibiotics is examined. We demonstrate that both [P.] pneumotropica biotypes but not [A.] muris are able to form robust biofilms in vitro, a phenotype which is widely spread among the field isolates. The biofilm inhibition and dispersal assays by proteinase and DNase lead to a strong inhibition in biofilm formation when added at the initiation of the biofilm formation and dispersed pre-formed [P.] pneumotropica biofilms, revealing thus that proteins and extracellular DNA are essential in biofilm formation and structure. Sodium periodate inhibited the bacterial growth when added at the beginning of the biofilm formation assay, making difficult the assessment of the role of β-1,6-linked polysaccharides in the biofilm formation, and had a biofilm stimulating effect when added on pre-established mature biofilms of [P.] pneumotropica biotype Heyl and a majority of [P.] pneumotropica biotype Jawetz strains, suggesting that the presence of β-1,6-linked polysaccharides on the bacterial surface might attenuate the biofilm production. Conversely, no effect or a decrease in the biofilm quantity was observed by biofilm dispersal using sodium periodate on further biotype Jawetz isolates, suggesting that polysaccharides might be incorporated in the biofilm structure. We additionally show that [P.] pneumotropica cells enclosed in biofilms were less sensitive to treatment with amoxicillin and enrofloxacin than planktonic bacteria. Taken together, these findings provide a first step in understanding of the biofilm mechanisms in [P.] pneumotropica, which might contribute to elucidation of colonization and pathogenesis mechanisms for these obligate inhabitants of the mouse mucosa.

No MeSH data available.


Related in: MedlinePlus

Reduction of cellular viability of planktonic and biofilm cells of [P.] pneumotropica after 3 hours exposure to antibiotics.The y-axis indicates the log10 cfu/ml recovered from the controls without antibiotics (black bars) in comparison to bacteria treated with amoxicillin (grey bars) or enrofloxacin (white bars) in planktonic or biofilm status. Bars represent mean values + standard deviation of three independent experiments.
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pone.0138778.g008: Reduction of cellular viability of planktonic and biofilm cells of [P.] pneumotropica after 3 hours exposure to antibiotics.The y-axis indicates the log10 cfu/ml recovered from the controls without antibiotics (black bars) in comparison to bacteria treated with amoxicillin (grey bars) or enrofloxacin (white bars) in planktonic or biofilm status. Bars represent mean values + standard deviation of three independent experiments.

Mentions: The MICs of amoxicillin to all [P.] pneumotropica strains used were higher for the bacteria grown in biofilms than for planktonic cells (Table 2). The MICs of enrofloxacin was similar for both biofilm and planktonic cells in three of the strains used (ATCC12555T, CCUG12398T, 394/12), whereas for the strain 1070/11 it was higher for the bacteria grown in biofilm (Table 2). Fig 8 presents the reduction in viability of selected [P.] pneumotropica strains after exposure of planktonic cells or biofilms to amoxicillin and enrofloxacin in comparison to non treated controls. The antibiotics treatment reduced significantly the number of viable cells in both planktonic and biofilm cells in comparison to the non treated controls. However, the viable cells from the antibiotics treated samples were outnumbered by the control cells by a factor of about 10:1 in the case of biofilms and by a factor of about 105:1 in the case of planktonic cells, showing thus a more severe reduction in the cellular viability for the planktonic in comparison to biofilm bacteria.


Characterization of Biofilm Formation in [Pasteurella] pneumotropica and [Actinobacillus] muris Isolates of Mouse Origin.

Sager M, Benten WP, Engelhardt E, Gougoula C, Benga L - PLoS ONE (2015)

Reduction of cellular viability of planktonic and biofilm cells of [P.] pneumotropica after 3 hours exposure to antibiotics.The y-axis indicates the log10 cfu/ml recovered from the controls without antibiotics (black bars) in comparison to bacteria treated with amoxicillin (grey bars) or enrofloxacin (white bars) in planktonic or biofilm status. Bars represent mean values + standard deviation of three independent experiments.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4592018&req=5

pone.0138778.g008: Reduction of cellular viability of planktonic and biofilm cells of [P.] pneumotropica after 3 hours exposure to antibiotics.The y-axis indicates the log10 cfu/ml recovered from the controls without antibiotics (black bars) in comparison to bacteria treated with amoxicillin (grey bars) or enrofloxacin (white bars) in planktonic or biofilm status. Bars represent mean values + standard deviation of three independent experiments.
Mentions: The MICs of amoxicillin to all [P.] pneumotropica strains used were higher for the bacteria grown in biofilms than for planktonic cells (Table 2). The MICs of enrofloxacin was similar for both biofilm and planktonic cells in three of the strains used (ATCC12555T, CCUG12398T, 394/12), whereas for the strain 1070/11 it was higher for the bacteria grown in biofilm (Table 2). Fig 8 presents the reduction in viability of selected [P.] pneumotropica strains after exposure of planktonic cells or biofilms to amoxicillin and enrofloxacin in comparison to non treated controls. The antibiotics treatment reduced significantly the number of viable cells in both planktonic and biofilm cells in comparison to the non treated controls. However, the viable cells from the antibiotics treated samples were outnumbered by the control cells by a factor of about 10:1 in the case of biofilms and by a factor of about 105:1 in the case of planktonic cells, showing thus a more severe reduction in the cellular viability for the planktonic in comparison to biofilm bacteria.

Bottom Line: We demonstrate that both [P.] pneumotropica biotypes but not [A.] muris are able to form robust biofilms in vitro, a phenotype which is widely spread among the field isolates.Conversely, no effect or a decrease in the biofilm quantity was observed by biofilm dispersal using sodium periodate on further biotype Jawetz isolates, suggesting that polysaccharides might be incorporated in the biofilm structure.We additionally show that [P.] pneumotropica cells enclosed in biofilms were less sensitive to treatment with amoxicillin and enrofloxacin than planktonic bacteria.

View Article: PubMed Central - PubMed

Affiliation: Central Animal Research Facility, Heinrich-Heine-University, University Hospital, Düsseldorf, Germany.

ABSTRACT
[Pasteurella] pneumotropica biotypes Jawetz and Heyl and [Actinobacillus] muris are the most prevalent Pasteurellaceae species isolated from laboratory mouse. However, mechanisms contributing to their high prevalence such as the ability to form biofilms have not been studied yet. In the present investigation we analyze if these bacterial species can produce biofilms in vitro and investigate whether proteins, extracellular DNA and polysaccharides are involved in the biofilm formation and structure by inhibition and dispersal assays using proteinase K, DNase I and sodium periodate. Finally, the capacity of the biofilms to confer resistance to antibiotics is examined. We demonstrate that both [P.] pneumotropica biotypes but not [A.] muris are able to form robust biofilms in vitro, a phenotype which is widely spread among the field isolates. The biofilm inhibition and dispersal assays by proteinase and DNase lead to a strong inhibition in biofilm formation when added at the initiation of the biofilm formation and dispersed pre-formed [P.] pneumotropica biofilms, revealing thus that proteins and extracellular DNA are essential in biofilm formation and structure. Sodium periodate inhibited the bacterial growth when added at the beginning of the biofilm formation assay, making difficult the assessment of the role of β-1,6-linked polysaccharides in the biofilm formation, and had a biofilm stimulating effect when added on pre-established mature biofilms of [P.] pneumotropica biotype Heyl and a majority of [P.] pneumotropica biotype Jawetz strains, suggesting that the presence of β-1,6-linked polysaccharides on the bacterial surface might attenuate the biofilm production. Conversely, no effect or a decrease in the biofilm quantity was observed by biofilm dispersal using sodium periodate on further biotype Jawetz isolates, suggesting that polysaccharides might be incorporated in the biofilm structure. We additionally show that [P.] pneumotropica cells enclosed in biofilms were less sensitive to treatment with amoxicillin and enrofloxacin than planktonic bacteria. Taken together, these findings provide a first step in understanding of the biofilm mechanisms in [P.] pneumotropica, which might contribute to elucidation of colonization and pathogenesis mechanisms for these obligate inhabitants of the mouse mucosa.

No MeSH data available.


Related in: MedlinePlus