Characterization of Extended-Spectrum β-Lactamase Genes Found among Escherichia coli Isolates from Duck and Environmental Samples Obtained on a Duck Farm

Abstract

<jats:title>ABSTRACT</jats:title><jats:p>In this study, we focused on evaluating the occurrence of extended-spectrum β-lactamase (ESBL)-producing<jats:named-content content-type="genus-species">Escherichia coli</jats:named-content>in fecal samples of healthy ducks and environmental samples from a duck farm in South China. Duck cloacal swabs and pond water samples were cultivated on MacConkey agar plates supplemented with ceftiofur. Individual colonies were examined for ESBL production. Bacteria identified as<jats:named-content content-type="genus-species">E. coli</jats:named-content>were screened for the presence of ESBL and plasmid-borne AmpC genes. The genetic relatedness, plasmid replicon type, and genetic background were determined. Of 245 samples analyzed, 123 had<jats:named-content content-type="genus-species">E. coli</jats:named-content>isolates with ceftiofur MICs higher than 8 μg/ml (116 [50.4%] from 230 duck samples and 7 [46.7%] from 15 water samples).<jats:italic>bla</jats:italic><jats:sub>CTX-M</jats:sub>,<jats:italic>bla</jats:italic><jats:sub>SHV-12</jats:sub>,<jats:italic>bla</jats:italic><jats:sub>CMY-2</jats:sub>, and<jats:italic>bla</jats:italic><jats:sub>DHA-1</jats:sub>were identified in 108, 5, 9, and 1 isolates, respectively. The most common<jats:italic>bla</jats:italic><jats:sub>CTX-M</jats:sub>genes were<jats:italic>bla</jats:italic><jats:sub>CTX-M-27</jats:sub>(<jats:italic>n</jats:italic>= 34),<jats:italic>bla</jats:italic><jats:sub>CTX-M-55</jats:sub>(<jats:italic>n</jats:italic>= 27),<jats:italic>bla</jats:italic><jats:sub>CTX-M-24e</jats:sub>(<jats:italic>n</jats:italic>= 22), and<jats:italic>bla</jats:italic><jats:sub>CTX-M-105</jats:sub>(<jats:italic>n</jats:italic>= 20), followed by<jats:italic>bla</jats:italic><jats:sub>CTX-M-14a</jats:sub>,<jats:italic>bla</jats:italic><jats:sub>CTX-M-14b</jats:sub>,<jats:italic>bla</jats:italic><jats:sub>CTX-M-24a</jats:sub>, and<jats:italic>bla</jats:italic><jats:sub>CTX-M-24b</jats:sub>. Although most of the CTX-M producers had distinct pulsotypes, clonal transmission between duck and water isolates was observed.<jats:italic>bla</jats:italic><jats:sub>CTX-M</jats:sub>genes were carried by transferable IncN, IncF, and untypeable plasmids. The novel CTX-M gene<jats:italic>bla</jats:italic><jats:sub>CTX-M-105</jats:sub>was flanked by two hypothetical protein sequences, partial IS<jats:italic>Ecp1</jats:italic>upstream and truncated IS<jats:italic>903D</jats:italic>,<jats:italic>iroN</jats:italic>,<jats:italic>orf1</jats:italic>, and a Tn<jats:italic>1721</jats:italic>-like element downstream. It is suggested that the horizontal transfer of<jats:italic>bla</jats:italic><jats:sub>CTX-M</jats:sub>genes mediated by mobile elements and the clonal spread of CTX-M-producing<jats:named-content content-type="genus-species">E. coli</jats:named-content>isolates contributed to the dissemination of<jats:italic>bla</jats:italic><jats:sub>CTX-M</jats:sub>in the duck farm. Our findings highlight the importance of ducks for the dissemination of transferable antibiotic resistance genes into the environment.</jats:p>

Characteristics of CTX-M Extended-Spectrum β-Lactamase-Producing Escherichia coli Strains Isolated from Multiple Rivers in Southern Taiwan

“…As shown in Table 5, various ESBL-producing E. coli clones have been isolated from animals, although ST131 clones have not been detected in certain studies (28,30,(35)(36)(37)(38)(39)(40)(42)(43)(44)(45). The ST10, ST58, and ST155 clones have been detected in animals, water, and human isolates in the Netherlands, Canada, Chile, and China (28,30,35,(38)(39)(40)(41)(42)(43)(44)(45).…”

Genetic Characterization of IncI2 Plasmids Carrying bla CTX-M-55 Spreading in both Pets and Food Animals in China

“…Within this group, the most dominant variants are bla CTX-M- 15 and bla CTX-M- 14 , found in isolates from humans, animals, and the environment all over the world (2,3). In China, CTX-M-14 is the dominant extendedspectrum ␤-lactamase (ESBL) among human and animal isolates (4-6), but CTX-M-55, rather than CTX-M-15, has become the second most frequently identified CTX-M gene, especially in Escherichia coli from animals (5)(6)(7)(8). Like bla CTX-M- 15 , bla CTX-M-55 encodes an ESBL with enhanced activity against ceftazidime and is generally found in an ISEcp1-mediated transposition unit carried by plasmids (9).…”

“…The remaining 14 transconjugants carrying bla CTX-M-55 and 20 additional E. coli isolates carrying bla CTX-M-55 from pets (n ϭ 2) and food animals (n ϭ 18; Table 1) from our other previous studies (6,7,20) were also examined for pHN1122-1-like plasmids. All 20 of the additional isolates gave transconjugants carrying bla CTX-M-55 in streptomycin-resistant E. coli C600 with selection on cefotaxime (2 g/ml) and streptomycin (2,000 g/ml).…”

Detection of extended spectrum beta-lactamases and resistance in members of the Enterobacteriaceae family isolated from healthy sheep and dogs in Umuarama, Paraná, Brazil

“…Some studies have detected high isolation frequencies of ESBL-producing E. coli in pets and production animals (MORENO et al, 2008;MA et al, 2009MA et al, , 2012. The isolates harbored bla CTX-M-1 , bla CTX-M-2 , bla CTX-M-8 or bla CTX-M-15 genes and, in some cases, a single strain presented more than one type of ESBL gene, with the presence of bla CTX-like associated with other ESBL genes, such as bla TEM (MORENO et al, 2008).…”

“…The presence of gram-negative bacilli carrying ESBL genes in pets and production animals has been reported in several studies. However, these studies are limited in Brazil, especially on the oral cavity of pets, as current research has mainly focused on the analysis of feces and urine samples (MORENO et al, 2008;MA et al, 2009MA et al, , 2012.…”