Limits...
Antimicrobial resistance characteristics and fitness of Gram-negative fecal bacteria from volunteers treated with minocycline or amoxicillin.

Kirchner M, Mafura M, Hunt T, Abu-Oun M, Nunez-Garcia J, Hu Y, Weile J, Coates A, Card R, Anjum MF - Front Microbiol (2014)

Bottom Line: A yearlong study was performed to examine the effect of antibiotic administration on the bacterial gut flora.Following amoxicillin administration, an increase in the proportion of amoxicillin resistant E. coli and a three-fold increase in the levels of bla TEM gene carriage was observed, an effect not observed in the other two treatment groups.Although there were no unique characteristics associated with plasmids from persistent or transient isolates, PM assays showed transient isolates had greater adaptability to a range of antiseptic biocides and tetracycline; characteristics which were lost in some, but not all persistent isolates.

View Article: PubMed Central - PubMed

Affiliation: Department of Bacteriology, Animal and Plant Health Agency Addlestone, UK.

ABSTRACT
A yearlong study was performed to examine the effect of antibiotic administration on the bacterial gut flora. Gram-negative facultative anaerobic bacteria were recovered from the feces of healthy adult volunteers administered amoxicillin, minocycline or placebo, and changes determined in antimicrobial resistance (AMR) gene carriage. Seventy percent of the 1039 facultative anaerobic isolates recovered were identified by MALDI-TOF as Escherichia coli. A microarray used to determine virulence and resistance gene carriage demonstrated that AMR genes were widespread in all administration groups, with the most common resistance genes being bla TEM, dfr, strB, tet(A), and tet(B). Following amoxicillin administration, an increase in the proportion of amoxicillin resistant E. coli and a three-fold increase in the levels of bla TEM gene carriage was observed, an effect not observed in the other two treatment groups. Detection of virulence genes, including stx1A, indicated not all E. coli were innocuous commensals. Approximately 150 E. coli collected from 6 participants were selected for pulse field gel electrophoresis (PFGE), and a subset used for characterisation of plasmids and Phenotypic Microarrays (PM). PFGE indicated some E. coli clones had persisted in volunteers for up to 1 year, while others were transient. Although there were no unique characteristics associated with plasmids from persistent or transient isolates, PM assays showed transient isolates had greater adaptability to a range of antiseptic biocides and tetracycline; characteristics which were lost in some, but not all persistent isolates. This study indicates healthy individuals carry bacteria harboring resistance to a variety of antibiotics and biocides in their intestinal tract. Antibiotic administration can have a temporary effect of selecting bacteria, showing co-resistance to multiple antibiotics, some of which can persist within the gut for up to 1 year.

No MeSH data available.


Related in: MedlinePlus

The percentage of blaTEM positive E. coli collected from amoxicillin and placebo treatment groups.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4269195&req=5

Figure 3: The percentage of blaTEM positive E. coli collected from amoxicillin and placebo treatment groups.

Mentions: The increase in the resistance genotype observed in the amoxicillin group was due to an overall increase in the percentage of blaTEM positive E. coli present in this group from day 0 (13.9%) to day 11 (48.3%), which was sustained for up to 30 days following amoxicillin administration (Figure 3); after this period there was a fall in the level of TEM positive isolates although it did not return to pre-administration levels. However, only half the participants challenged with amoxicillin accounted for this increase, indicating person to person variation (data not shown). An increase in the proportion of tet(B) positive E. coli (from 8.3 to 20%) was also observed immediately following amoxicillin administration. At 30 days post-administration, the levels of strB, sul1, intI1, dfr, and tet(A) increased above pre-administration levels; this was probably not a direct effect of ampicillin administration (data not shown). In the placebo group the proportion of blaTEM positive E. coli remained between 33 and 40% for the entire study. In the minocycline administration group the proportion of blaTEM positive E. coli decreased from 40 to 22% between day 0 and 11. However, the change was probably due to the small number of blaTEM positive isolates present in this group and not an effect of treatment (data not shown).


Antimicrobial resistance characteristics and fitness of Gram-negative fecal bacteria from volunteers treated with minocycline or amoxicillin.

Kirchner M, Mafura M, Hunt T, Abu-Oun M, Nunez-Garcia J, Hu Y, Weile J, Coates A, Card R, Anjum MF - Front Microbiol (2014)

The percentage of blaTEM positive E. coli collected from amoxicillin and placebo treatment groups.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4269195&req=5

Figure 3: The percentage of blaTEM positive E. coli collected from amoxicillin and placebo treatment groups.
Mentions: The increase in the resistance genotype observed in the amoxicillin group was due to an overall increase in the percentage of blaTEM positive E. coli present in this group from day 0 (13.9%) to day 11 (48.3%), which was sustained for up to 30 days following amoxicillin administration (Figure 3); after this period there was a fall in the level of TEM positive isolates although it did not return to pre-administration levels. However, only half the participants challenged with amoxicillin accounted for this increase, indicating person to person variation (data not shown). An increase in the proportion of tet(B) positive E. coli (from 8.3 to 20%) was also observed immediately following amoxicillin administration. At 30 days post-administration, the levels of strB, sul1, intI1, dfr, and tet(A) increased above pre-administration levels; this was probably not a direct effect of ampicillin administration (data not shown). In the placebo group the proportion of blaTEM positive E. coli remained between 33 and 40% for the entire study. In the minocycline administration group the proportion of blaTEM positive E. coli decreased from 40 to 22% between day 0 and 11. However, the change was probably due to the small number of blaTEM positive isolates present in this group and not an effect of treatment (data not shown).

Bottom Line: A yearlong study was performed to examine the effect of antibiotic administration on the bacterial gut flora.Following amoxicillin administration, an increase in the proportion of amoxicillin resistant E. coli and a three-fold increase in the levels of bla TEM gene carriage was observed, an effect not observed in the other two treatment groups.Although there were no unique characteristics associated with plasmids from persistent or transient isolates, PM assays showed transient isolates had greater adaptability to a range of antiseptic biocides and tetracycline; characteristics which were lost in some, but not all persistent isolates.

View Article: PubMed Central - PubMed

Affiliation: Department of Bacteriology, Animal and Plant Health Agency Addlestone, UK.

ABSTRACT
A yearlong study was performed to examine the effect of antibiotic administration on the bacterial gut flora. Gram-negative facultative anaerobic bacteria were recovered from the feces of healthy adult volunteers administered amoxicillin, minocycline or placebo, and changes determined in antimicrobial resistance (AMR) gene carriage. Seventy percent of the 1039 facultative anaerobic isolates recovered were identified by MALDI-TOF as Escherichia coli. A microarray used to determine virulence and resistance gene carriage demonstrated that AMR genes were widespread in all administration groups, with the most common resistance genes being bla TEM, dfr, strB, tet(A), and tet(B). Following amoxicillin administration, an increase in the proportion of amoxicillin resistant E. coli and a three-fold increase in the levels of bla TEM gene carriage was observed, an effect not observed in the other two treatment groups. Detection of virulence genes, including stx1A, indicated not all E. coli were innocuous commensals. Approximately 150 E. coli collected from 6 participants were selected for pulse field gel electrophoresis (PFGE), and a subset used for characterisation of plasmids and Phenotypic Microarrays (PM). PFGE indicated some E. coli clones had persisted in volunteers for up to 1 year, while others were transient. Although there were no unique characteristics associated with plasmids from persistent or transient isolates, PM assays showed transient isolates had greater adaptability to a range of antiseptic biocides and tetracycline; characteristics which were lost in some, but not all persistent isolates. This study indicates healthy individuals carry bacteria harboring resistance to a variety of antibiotics and biocides in their intestinal tract. Antibiotic administration can have a temporary effect of selecting bacteria, showing co-resistance to multiple antibiotics, some of which can persist within the gut for up to 1 year.

No MeSH data available.


Related in: MedlinePlus