Effect of the presence of the antimicrobial tylosin in swine waste on anaerobic treatment

2009

Appl Environ Microbiol

Self Cite

To investigate the relationship between agricultural antimicrobial use and resistance, a variety of methods for quantification of macrolide-lincosamide-streptogramin B (MLS B ) resistance were applied to organic swine farm manure samples. Fluorescence in situ hybridization was used to indirectly quantify the specific rRNA methylation resulting in MLS B resistance. Using this method, an unexpectedly high prevalence of ribosomal methylation and, hence, predicted MLS B resistance was observed in manure samples from two swine finisher farms that reported no antimicrobial use (37.6% ؎ 6.3% and 40.5% ؎ 5.4%, respectively). A culture-based method targeting relatively abundant clostridia showed a lower but still unexpectedly high prevalence of resistance at both farms (27.7% ؎ 11.3% and 11.7% ؎ 8.6%, respectively), while the prevalence of resistance in cultured fecal streptococci was low at both farms (4.0%). These differences in the prevalence of resistance across microorganisms suggest the need for caution when extrapolating from data obtained with indicator organisms. A third antimicrobial-free swine farm, a breeder-to-finisher operation, had low levels of MLS B resistance in manure samples with all methods used (<9%). Tetracycline antimicrobials were detected in manure samples from one of the finisher farms and may provide a partial explanation for the high level of MLS B resistance. Taken together, these findings highlight the need for a more fundamental understanding of the relationship between antimicrobial use and the prevalence of antimicrobial resistance.

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Macrolide Resistance in Microorganisms at Antimicrobial-Free Swine Farms

Zhou

Raskin

2009

Appl Environ Microbiol

Self Cite

“…Specifically, a slight decrease in the prevalence of cells that hybridized to the bacterial probe but not the MLS B probe (presumed MLS B resistant bacteria) occurred after tylosin addition, from 56.2 ± 3.9% in the absence of tylosin to 38.5 ± 3.2% and 39.3 ± 5.9% under low and high tylosin dosing, respectively ( Figure 6). Angenent et al (2008) reported an increase in MLS B resistance in an ASBR treating swine waste but attributed their results to the enrichment with resistant bacteria present in the reactor feed. Occurrence of macrolide resistant organisms in swine waste has been reported previously (Chen et al, 2010;Holzel et al, 2010;Jindal et al, 2006).…”

Section: Mls B Resistancementioning

confidence: 99%

Effects of the antimicrobial tylosin on the microbial community structure of an anaerobic sequencing batch reactor

Shimada

Biotech & Bioengineering

et al. 2010

Self Cite

Morgenroth, Eberhard; and Raskin, Lutgarde, "Effects of the antimicrobial tylosin on the microbial community structure of an anaerobic sequencing batch reactor" (2010). Civil Engineering Faculty Publications. 37. http://digitalcommons.unl.edu/civilengfacpub/37 AbstractThe effects of the antimicrobial tylosin on a methanogenic microbial community were studied in a glucosefed laboratory-scale anaerobic sequencing batch reactor (ASBR) exposed to stepwise increases of tylosin (0, 1.67, and 167 mg/L). The microbial community structure was determined using quantitative fluorescence in situ hybridization (FISH) and phylogenetic analyses of bacterial 16S ribosomal RNA (rRNA) gene clone libraries of biomass samples. During the periods without tylosin addition and with an influent tylosin concentration of 1.67 mg/L, 16S rRNA gene sequences related to Syntrophobacter were detected and the relative abundance of Methanosaeta species was high. During the highest tylosin dose of 167 mg/L, 16S rRNA gene sequences related to Syntrophobacter species were not detected and the relative abundance of Methanosaeta decreased considerably. Throughout the experimental period, Propionibacteriaceae and high GC Gram-positive bacteria were present, based on 16S rRNA gene sequences and FISH analyses, respectively. The accumulation of propionate and subsequent reactor failure after long-term exposure to tylosin are attributed to the direct inhibition of propionate-oxidizing syntrophic bacteria closely related to Syntrophobacter and the indirect inhibition of Methanosaeta by high propionate concentrations and low pH.

“…Although the MLS B antimicrobials are chemically distinct, methylation or mutation of a single base of the 23S rRNA prevents binding and results in cross-resistance to all three classes (29). The prevalence of MLS B antimicrobial resistance in the microbial community can therefore be quantified indirectly by hybridization of an oligonucleotide probe to unmethylated, MLS B -sensitive ribosomes, using either membrane hybridization (1,10) or FISH (31). These methods do not require culturing or a comprehensive knowledge of the diversity of resistance gene sequences, but they do not detect resistance to specific antimicrobials that results from other mechanisms, such as macrolide efflux.…”

mentioning

confidence: 99%

Effects of Swine Manure on Macrolide, Lincosamide, and Streptogramin B Antimicrobial Resistance in Soils

Zhou

Raskin

2010

Appl Environ Microbiol

Self Cite

Current agricultural practices involve inclusion of antimicrobials in animal feed and result in manure containing antimicrobials and antimicrobial-resistant microorganisms. This work evaluated the effects of land application of swine manure on the levels of tetracycline, macrolide, and lincosamide antimicrobials and on macrolide, lincosamide, and streptogramin B (MLS B ) resistance in field soil samples and laboratory soil batch tests. MLS B and tetracycline antimicrobials were quantified after solid-phase extraction using liquid chromatography-tandem mass spectrometry. The prevalence of the ribosomal modification responsible for MLS B resistance in the same samples was quantified using fluorescence in situ hybridization. Macrolide antimicrobials were not detected in soil samples, while tetracyclines were detected, suggesting that the latter compounds persist in soil. No significant differences in ribosomal methylation or presumed MLS B resistance were observed when amended and unamended field soils were compared, although a transient (<20-day) increase was observed in most batch tests. Clostridium cluster XIVa accounted for the largest fraction of resistant bacteria identified in amended soils. Overall, this study did not detect a persistent increase in the prevalence of MLS B resistance due to land application of treated swine manure.