Geographical variation in antibiotic resistance profiles of Escherichia coli isolated from swine, poultry, beef and dairy cattle farm water retention ponds in Florida1

Abstract

Aims: The aim of this study was to assess geographical variation in multiple antibiotic resistance (MAR) profiles of livestock Escherichia coli as well as to evaluate the ability of MAR profiles to differentiate sources of faecal pollution. Methods and Results: More than 2000 E. coli isolates were collected from water retention ponds and manure of swine, poultry, beef and dairy farms in south, central and north Florida, and analysed for MAR using nine antibiotics. There were significant differences in antibiotic resistance of E. coli by season and livestock type for more than one antibiotic, but regional differences were significant only for ampicillin. Over the three regions, discriminant analysis using MAR profiles correctly classified 27% of swine, 49% of poultry, 56% of beef and 51% of dairy isolates. Conclusions: Regional variations in MAR combined with moderate discrimination success suggest that MAR profiles of E. coli may only be marginally successful in identifying sources of faecal pollution. Significance and Impact of the Study: This study demonstrates the existence of regional and seasonal differences in MAR profiles as well as the limited ability of MAR profiles to discriminate among livestock sources.

Perfil de resistência antimicrobiana de isolados de Escherichia coli obtidos de águas superficiais e subterrâneas, em área de produção de suínos

“…A resistência de Enterobacteriaceae, como E. coli, a esses compostos é mediada por β-lactamases de espectro ampliado ("extended spectrum β-lactamases" ou ESBL), as quais são mediadas por plasmídios que contem genes que codificam ESBL (Garza-Ramos et al, 2007). Para identificar de forma precisa a origem dos microrganismos isolados, a ribotipagem de linhagens de E. coli poderia ser utilizada (Parveen et al, 2005).…”

“…As atividades agrícolas relacionadas à produção animal intensiva têm sido apontadas como a maior fonte de poluição fecal em águas superficiais e subterrâneas (Parveen et al, 2005). A utilização de antimicrobianos, de maneira excessiva e indiscriminada na produção animal intensiva, tem desencadeado o aumento no número de microrganismos resistentes (Harakeh et al, 2006), os quais podem ser transportados para o solo, alimentos e ambientes aquáticos (Mckeon et al, 1995).…”

Use of ‘natural’ products as alternatives to antibiotic feed additives in ruminant production

“…This concern is fuelled by the emergence of antibiotic resistance in many human pathogenic bacteria (Manero et al, 2006;Parveen et al, 2006), the release of contaminating residues into the environment (water, soil, etc. ) (Yang and Carlson, 2004) and the risk that growth-promoting antibiotic residues may occur in foods of animal origin.…”

Molecular Indicators Used in the Development of Predictive Models for Microbial Source Tracking

“…LDM include antibiotic resistance analysis, carbon source utilization, repetitive PCR, and ribotyping. However, the geographic and temporal stability and the numerical methods used for these LDM have been questioned (26,44). Some cultivation-based methods have already been described, such as the detection of specific enterotoxins of E. coli strains (30,31,43), the differentiation and enumeration of sorbitol-fermenting bifidobacteria (10,37), and the enumeration of phages that infect host-specific Bacteroides spp.…”