Aquariums as Reservoirs for Multidrug-resistant<i>Salmonella</i>Paratyphi B

Levings, Renee S.; Lightfoot, Diane; Hall, Ruth M.; Djordjevic, Steven P.

doi:10.3201/eid1203.051085

Cited by 39 publications

(33 citation statements)

References 14 publications

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“…Resistance profiles were determined as described previously (22) and were confirmed and extended according to the CDS method (calibrated dichotomous sensitivity test [http://web.med.unsw.edu.au/cdstest]), using antibiotic discs (Oxoid, New Hampshire, England) containing ampicillin (25 g), chloramphenicol (30 g), florfenicol (30 g), gentamicin (10 g), kanamycin (50 g), neomycin (30 g), streptomycin (25 g), spectinomycin (25 g), sulfafurazole (300 g), tetracycline (30 g), tobramicin (10 g), trimethoprim (5 g), nalidixic acid (30 g), and ciprofloxacin (5 g). Pulsed-field gel electrophoresis of XbaI-digested whole-cell DNA and IS200 analysis were carried out as described previously (21).…”

Section: Methodsmentioning

confidence: 99%

SGI2, a Relative ofSalmonellaGenomic Island SGI1 with an Independent Origin

Levings

Djordjevic

Hall

2008

Antimicrob Agents Chemother

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Multiply antibiotic-resistant Salmonella enterica serovar Emek strains isolated in Australia and the United Kingdom had similar features, suggesting that they all belong to a single clone. These strains all contain SGI2 (formerly SGI1-J), an independently formed relative of Salmonella genomic island SGI1. In SGI2, the complex class 1 integron which includes all of the resistance genes is not located between tnpR (S027) and S044 as in SGI1 and SGI1 variants. Instead, tnpR was found to be adjacent to S044, and the integron is located 6.9 kb away, within S023. In both SGI1 and SGI2, the 25-bp inverted repeats that mark the outer ends of class 1 integrons are flanked by a 5-bp duplication of the target, indicating that incorporation of the integron was by transposition. A small number of differences between the sequences of the backbones of SGI1 and SGI2 were also found. Hence, a class 1 integron has entered two different variants of the SGI backbone to generate two distinct lineages. Despite this, the integron in SGI2 has a complex structure that is very similar to that of In104 in SGI1. Differences are in the cassette arrays and in the gene which encodes the chloramphenicol and florfenicol efflux protein. The CmlA9 protein, encoded by InEmek, is only 92.8% identical to FloRc (also a CmlA family protein) from SGI1. A variant form of SGI2, SGI2-A, which has lost the tet(G) and cmlA9 resistance determinants, was found in one strain.

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Section: Methodsmentioning

confidence: 99%

SGI2, a Relative ofSalmonellaGenomic Island SGI1 with an Independent Origin

Levings

Djordjevic

Hall

2008

Antimicrob Agents Chemother

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“…Multiply antibiotic-resistant Salmonella serovar Paratyphi B dT ϩ strains have been isolated from human infections in different parts of the world since the late 1990s. One type, with the resistance phenotype ApCmFlSmSpSuTc (Ap, ampicillin; Cm, chloramphenicol; Fl, florfenicol; Sm, streptomycin; Sp, spectinomycin; Su, sulfonamides; and Tc, tetracycline), have been recovered in Canada (23), England, Wales, Scotland and the Channel Islands (32), France (34), Australia (17,18), and Japan (1). In most of these isolates, the resistance genes blaP1, floR (or cmlA3), aadA2, sul1, and tetA(G) are found in a complex class 1 integron (Fig.…”

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confidence: 99%

Emergence and Evolution of Multiply Antibiotic-ResistantSalmonella entericaSerovar Paratyphi Bd-Tartrate-Utilizing Strains Containing SGI1

Djordjevic

Cain

Evershed

et al. 2009

Antimicrob Agents Chemother

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The first Australian isolate of Salmonella enterica serovar Paratyphi B D-tartrate-utilizing (dT ؉ ) that is resistant to ampicillin, chloramphenicol, florfenicol, streptomycin, spectinomycin, sulfonamides, and tetracycline (ApCmFlSmSpSuTc) and contains SGI1 was isolated from a patient with gastroenteritis in early 1995. This is the earliest reported isolation globally. The incidence of infections caused by these SGI1-containing multiply antibiotic-resistant S. enterica serovar Paratyphi B dT ؉ strains increased during the next few years and occurred sporadically in all states of Australia. Several molecular criteria were used to show that the early isolates are very closely related to one another and to strains isolated during the following few years and in 2000 and 2003 from home aquariums and their owners. Early isolates from travelers returning from Indonesia shared the same features. Thus, they appear to represent a true clone arising from a single cell that acquired SGI1. Some minor differences in the resistance profiles and molecular profiles also were observed, indicating the ongoing evolution of the clone, and phage type differences were common, indicating that this is not a useful epidemiological marker over time. Three isolates from 1995, 1998, and 1999 contained a complete sul1 gene but were susceptible to sulfamethoxazole due to a point mutation that creates a premature termination codon. This SGI1 type was designated SGI1-R. The loss of resistance genes also was examined. When strains were grown for many generations in the absence of antibiotic selection, the loss of SGI1 was not detected. However, variants SGI1-C (resistance profile SmSpSu) and SGI1-B (resistant to ApSu), which had lost part of the integron, arose spontaneously, presumably via homologous recombination between duplications in the In104 complex integron.SGI1 was first identified in Salmonella enterica serovar Typhimurium DT104 strains with the ampicillin, chloramphenicol, florfenicol, streptomycin, spectinomycin, sulfonamides, and tetracycline (ApCmFlSmSpSuTc) resistance phenotype (4), and SGI1, or variants of it with different resistance phenotypes and resistance genes, have since been found in many Salmonella serotypes (10,18,19,24,33) and also in Proteus mirabilis (2, 5). SGI1 is an integrating element that can move into new hosts by transduction (31) or via mobilization by an IncA/C plasmid (12), and it establishes itself by integrating into the host chromosome at the end of the thdF gene. However, these events likely are quite rare, and it is possible that all of the SGI1-containing strains of any particular serovar arose from a single cell that acquired the SGI1 genomic island and then expanded in an antibiotic-selective environment and subsequently spread around the globe. A single-cell origin for the widespread multiply antibiotic-resistant S. enterica serovar Typhimurium DT104 clone that contains SGI1 is supported by the finding that the earliest DT104 strains of this type isolated in the United States are identical to thos...

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“…It was only sporadically isolated from various sources within the last 9 years. Possibly, human-to-human transmission might play a role for dissemination or other unidentified sources such as vegetables (32), fish aquariums (25), or goat's milk cheese (10).…”

Section: Discussionmentioning

confidence: 99%

“…Strains encode the Salmonella genomic island 1 (SGI1) originally described in S. enterica serovar Typhimurium DT104 (5). They are usually resistant to ampicillin, chloramphenicol, streptomycin, spectinomycin, sulfonamides, and tetracyclines and have not yet been found in poultry but in tropical fish aquaria (25) and cattle (13). In France, the SGI1-containing clone was frequently found in clinical isolates of S. enterica serovar Paratyphi B (DTϩ), but no potential sources of infection could be identified (35).…”

Section: Discussionmentioning

confidence: 99%

“…It was shown that this variant is multidrug resistant, carrying a class 2 integron-associated dfrA1-sat1-aadA1 gene cassette conferring resistance to trimethoprim, streptomycin, and spectinomycin (27), and that it possesses a particular pathogenicity gene repertoire (21). Outbreaks caused by S. enterica serovar Paratyphi B (DTϩ) have been associated with goat's milk cheese in France (10), alfalfa sprouts or aquariums in Canada (15,32), tropical fish aquariums in Australia (25), turtle exposure in the United States (17), and poultry in several European countries (27,33).…”

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Human Infections Attributable to thed-Tartrate-Fermenting Variant of Salmonella enterica Serovar Paratyphi B in Germany Originate in Reptiles and, on Rare Occasions, Poultry

Toboldt

Helmuth

Fruth

et al. 2012

Appl Environ Microbiol

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In this study, the population structure, incidence, and potential sources of human infection caused by the D-tartrate-fermenting variant of Salmonella enterica serovar Paratyphi B [S. Paratyphi B (DT؉)] was investigated. In Germany, the serovar is frequently isolated from broilers. Therefore, a selection of 108 epidemiologically unrelated S. enterica serovar Paratyphi B (DT؉) strains isolated in Germany between 2002 and 2010 especially from humans, poultry/poultry meat, and reptiles was investigated by phenotypic and genotypic methods. Strains isolated from poultry and products thereof were strongly associated with multilocus sequence type ST28 and showed antimicrobial multiresistance profiles. Pulsed-field gel electrophoresis XbaI profiles were highly homogeneous, with only a few minor XbaI profile variants. All strains isolated from reptiles, except one, were strongly associated with ST88, another distantly related type. Most of the strains were susceptible to antimicrobial agents, and XbaI profiles were heterogeneous. Strains isolated from humans yielded seven sequence types (STs) clustering in three distantly related lineages. The first lineage, comprising five STs, represented mainly strains belonging to ST43 and ST149. The other two lineages were represented only by one ST each, ST28 and ST88. The relatedness of strains based on the pathogenicity gene repertoire (102 markers tested) was mostly in agreement with the multilocus sequence type. Because ST28 was frequently isolated from poultry but rarely in humans over the 9-year period investigated, overall, this study indicates that in Germany S. enterica serovar Paratyphi B (DT؉) poses a health risk preferentially by contact with reptiles and, to a less extent, by exposure to poultry or poultry meat.

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Aquariums as Reservoirs for Multidrug-resistantSalmonellaParatyphi B

Cited by 39 publications

References 14 publications

SGI2, a Relative ofSalmonellaGenomic Island SGI1 with an Independent Origin

SGI2, a Relative ofSalmonellaGenomic Island SGI1 with an Independent Origin

Emergence and Evolution of Multiply Antibiotic-ResistantSalmonella entericaSerovar Paratyphi Bd-Tartrate-Utilizing Strains Containing SGI1

Human Infections Attributable to thed-Tartrate-Fermenting Variant of Salmonella enterica Serovar Paratyphi B in Germany Originate in Reptiles and, on Rare Occasions, Poultry

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