Transfer of antibiotic resistance between commensal and pathogenic members of the Enterobacteriaceae under ileal conditions

Blake, Damer P.; Hillman, K.; Fenlon, D.R.; Low, J. C.

doi:10.1046/j.1365-2672.2003.01988.x

Cited by 137 publications

(101 citation statements)

References 32 publications

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“…Verotoxigenic E. coli strains were also identified within this cohort over the same period (35), and studies to examine whether these pathogens will accept resis-tance plasmids isolated from the commensal population are ongoing. Transmission of multiple-resistance phenotypes between epidemiologically unrelated commensal and pathogenic E. coli strains has recently been demonstrated in vitro under ileal conditions (7).…”

Section: Discussionmentioning

confidence: 99%

Molecular Epidemiology of Antimicrobial-Resistant Commensal Escherichia coli Strains in a Cohort of Newborn Calves

Hoyle

Yates

Chase-Topping

et al. 2005

Appl Environ Microbiol

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Pulsed-field gel electrophoresis (PFGE) was used to investigate the dissemination and diversity of ampicillin-resistant (Amp r ) and nalidixic acid-resistant (Nal r ) commensal Escherichia coli strains in a cohort of 48 newborn calves. Calves were sampled weekly from birth for up to 21 weeks and a single resistant isolate selected from positive samples for genotyping and further phenotypic characterization. The Amp r population showed the greatest diversity, with a total of 56 different genotype patterns identified, of which 5 predominated, while the Nal r population appeared to be largely clonal, with over 97% of isolates belonging to just two different PFGE patterns. Distinct temporal trends were identified in the distribution of several Amp r genotypes across the cohort, with certain patterns predominating at different points in the study. Cumulative recognition of new Amp r genotypes within the cohort was biphasic, with a turning point coinciding with the housing of the cohort midway through the study, suggesting that colonizing strains were from an environmental source on the farm. Multiply resistant isolates dominated the collection, with >95% of isolates showing resistance to at least two additional antimicrobials. Carriage of resistance to streptomycin, sulfamethoxazole, and tetracycline was the most common combination, found across several different genotypes, suggesting the possible spread of a common resistance element across multiple strains. The proportion of Amp r isolates carrying sulfamethoxazole resistance increased significantly over the study period (P < 0.05), coinciding with a decline in the most common genotype pattern. These data indicate that calves were colonized by a succession of multiply resistant strains, with a probable environmental source, that disseminated through the cohort over time.

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Section: Discussionmentioning

confidence: 99%

Molecular Epidemiology of Antimicrobial-Resistant Commensal Escherichia coli Strains in a Cohort of Newborn Calves

Hoyle

Yates

Chase-Topping

et al. 2005

Appl Environ Microbiol

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“…The primer pairs 5ЈCATGGCGTCAAAAAGG3Ј and 5ЈTGCAAGAACCTCC TC3Ј amplified a 434-bp region of the rl4 gene. The 50-l reaction mixture in the setup for reverse transcription-PCR (RT-PCR) contained 25 l of 2ϫ SuperScript one-step RT-PCR buffer (a buffer containing 0.4 mM of each deoxynucleoside triphosphate and 2.4 mM MgSO 4 [Invitrogen]), 0.2 M of each of the four primers, 1 l of SuperScript II RT/Platinum Taq mix (Invitrogen), and 5 l of the treated RNA sample. The RT-PCR cycling conditions and product gel electrophoresis were according to standard procedures.…”

Section: Methodsmentioning

confidence: 99%

High-Frequency Conjugation System Facilitates Biofilm Formation and pAMβ1 Transmission by Lactococcus lactis

Luo¹,

Wan²,

Wang

2005

Appl Environ Microbiol

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The importance of conjugation as a mechanism to spread biofilm determinants among microbial populations was illustrated with the gram-positive bacterium Lactococcus lactis. Conjugation triggered the enhanced expression of the clumping protein CluA, which is a main biofilm attribute in lactococci. Clumping transconjugants further transmitted the biofilm-forming elements among the lactococcal population at a much higher frequency than the parental nonclumping donor. This cell-clumping-associated high-frequency conjugation system also appeared to serve as an internal enhancer facilitating the dissemination of the broad-host-range drug resistance gene-encoding plasmid pAM␤1 within L. lactis, at frequencies more than 10,000 times higher than those for the nonclumping parental donor strain. The implications of this finding for antibiotic resistance gene dissemination are discussed.Lactococci are important fermentation starter cultures. As commensal organisms, they are widely distributed (19, 37) and can be found coexisting with many other organisms, including pathogens, in natural and food-processing environments, most commonly in the form of mixed-culture ecosystems. However, to date information regarding lactococcal biofilm formation is very limited (30). The contribution of commensal organisms in mixed-culture biofilm development involving pathogens and other risks associated with these biofilms have not been fully explored.Lactococci are susceptible to various gene transfer mechanisms (13). Many important traits, including lactose utilization, the proteolytic system, bacterial phage resistance, and nisin production and immunity, are associated with mobile elements. Of particular interest, a cell-clumping-associated high-frequency conjugal gene transfer system has been reported in two similar settings involving Lactococcus lactis strains ML3 and 712. In both cases, the conjugative elements, i.e., the sex factor in 712 and pRS01 in ML3, mobilized the transfer of the Lac plasmid to the recipient cells by forming plasmid cointegrates. Some of the conjugation progenies exhibited cell autoaggregation. When these clumping cells served as donors in the second round of mating, they transferred the Lac plasmid 10 2 to 10 7 times more efficiently than the original donor strain (1, 10, 40). Divalent ions were required for autoaggregation, and proteinase treatments significantly decreased both cell clumping (Clu ϩ ) and high-frequency conjugation (41). Strain MG1363 is a nonclumping, plasmid-cured derivative of strain 712 with the sex factor retained in the chromosome. A cluA gene, which encoded a putative cell surface protein containing the well-conserved hexapeptide LPXTGE, was cloned from the sex factor. Expression of the CluA protein through upstream fusion of a lactococcal heat shock promoter in MG1363 partially restored cell aggregation (16).It is anticipated that the biofilm environment would be suitable for gene transfer events such as conjugation and transformation. However, a two-way relationship was recently demonst...

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“…Use of commensal organisms is convenient and allows measurement of the resistance gene pool that may be transmitted to pathogenic bacteria. Several studies have indicated that interspecies resistance transfer occur in bacteria, and increased recovery of antimicrobial resistant faecal E. coli was seen in dairy farms affected with resistant salmonellosis [6,8,11]. The level of resistance in commensal enteric bacteria has been correlated with resistance in pathogenic bacteria [11].…”

Section: Introductionmentioning

confidence: 99%

Assessing the effect of a single dose florfenicol treatment in feedlot cattle on the antimicrobial resistance patterns in faecal Escherichia coli

2005

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-The objective of this clinical trial was to examine the effect of a single dose of florfenicol on antimicrobial resistance patterns in faecal E. coli of feedlot steers. Steers (n = 370), were purchased from two sources and housed in outdoor concrete floored pens. Two cattle from each pen (n = 42 pens, 84 cattle) were randomly selected for faecal sampling at study day 1, 14, 28, and 42. One sampled animal from each of 21 pens was randomly selected to receive a single 39.6 mg/kg dose of florfenicol subcutaneously at study day 11. Ten lactose positive colonies were isolated from faecal swabs and tested for antimicrobial resistance to 11 antimicrobials using the disk diffusion method. Zones of inhibition were grouped using cluster analysis and clusters were ordered by increasing multiple resistance. A cumulative logistic regression model using generalized estimating equations was used to assess factors associated with increasing levels of multiple resistance. Immediately post-treatment, all isolates obtained from treated cattle belonged to multiple resistant clusters containing chloramphenicol resistance. Though less pronounced in later sampling, resistance to chloramphenicol and other antimicrobials persisted. Antimicrobial treatment, sampling time and animal source, as well as interactions between these variables, were important predictors of the odds of E. coli belonging to a more resistant cluster. A very clear but transitory shift to increasingly multiple resistant faecal E. coli in response to florfenicol treatment was observed. There was no indication of horizontal transfer of resistant E. coli between steers. Level of resistance was influenced by complex interaction of animal source and previous management.antimicrobial resistance / food animal / florfenicol / Escherichia coli

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Transfer of antibiotic resistance between commensal and pathogenic members of the Enterobacteriaceae under ileal conditions

Cited by 137 publications

References 32 publications

Molecular Epidemiology of Antimicrobial-Resistant Commensal Escherichia coli Strains in a Cohort of Newborn Calves

Molecular Epidemiology of Antimicrobial-Resistant Commensal Escherichia coli Strains in a Cohort of Newborn Calves

High-Frequency Conjugation System Facilitates Biofilm Formation and pAMβ1 Transmission by Lactococcus lactis

Assessing the effect of a single dose florfenicol treatment in feedlot cattle on the antimicrobial resistance patterns in faecal Escherichia coli

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