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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 proportion of genotypically multi-resistant (i.e., carrying genes for 2 or more resistance gene class) isolate in each treatment group during the study.
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Figure 2: The proportion of genotypically multi-resistant (i.e., carrying genes for 2 or more resistance gene class) isolate in each treatment group during the study.

Mentions: In the minocycline group 36.7% of the total isolates recovered, from all time points in this group, carried genes for two or more antibiotic classes. In the amoxicillin and placebo groups this was, 35.5 and 38.5%, respectively. To assess any effect of antibiotic administration, we determined the change over time in the proportion of isolates with MDR genotype. In the amoxicillin group the proportion of isolates with MDR genotype increased between days 0 and 11 from 22 to 49% (Figure 2), which matched the phenotypic results obtained using a panel of 22 antimicrobial agents or combinations using the VITEK system (data not shown). In the minocycline administration group the proportion of isolates with a MDR genotype did not change between day 0 and 11 (36 and 38%, respectively; Figure 2) and in the placebo group, the proportion of isolates with an MDR genotype was on average 38.5%, for the entire study (range 29–54%); both matched the respective phenotypic data (data not shown). The wide range in the placebo was the effect of an increase in MDR isolates at 120 days to 54% from between 30 and 40% in first four and last sampling point; the cause of this increase was unknown.


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 proportion of genotypically multi-resistant (i.e., carrying genes for 2 or more resistance gene class) isolate in each treatment group during the study.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: The proportion of genotypically multi-resistant (i.e., carrying genes for 2 or more resistance gene class) isolate in each treatment group during the study.
Mentions: In the minocycline group 36.7% of the total isolates recovered, from all time points in this group, carried genes for two or more antibiotic classes. In the amoxicillin and placebo groups this was, 35.5 and 38.5%, respectively. To assess any effect of antibiotic administration, we determined the change over time in the proportion of isolates with MDR genotype. In the amoxicillin group the proportion of isolates with MDR genotype increased between days 0 and 11 from 22 to 49% (Figure 2), which matched the phenotypic results obtained using a panel of 22 antimicrobial agents or combinations using the VITEK system (data not shown). In the minocycline administration group the proportion of isolates with a MDR genotype did not change between day 0 and 11 (36 and 38%, respectively; Figure 2) and in the placebo group, the proportion of isolates with an MDR genotype was on average 38.5%, for the entire study (range 29–54%); both matched the respective phenotypic data (data not shown). The wide range in the placebo was the effect of an increase in MDR isolates at 120 days to 54% from between 30 and 40% in first four and last sampling point; the cause of this increase was unknown.

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