Urinary Tract Infections in a South American Population: Dynamic Spread of Class 1 Integrons and Multidrug Resistance by Homologous and Site-Specific Recombination

Abstract

One hundred four bacterial strains mediating urinary tract infections in separate individuals from a Uruguayan community were isolated. Forty-six strains conferred a multidrug resistance phenotype. All 104 strains were examined for the presence of class 1, 2, and 3 integrons. Class 1 integrons were found in 21 isolates across four distinct bacterial genera. A large class 1 integron in a Klebsiella pneumoniae strain was fully sequenced and was 29,093 bp in length. This integron probably arose by homologous recombination since it was embedded in a hybrid Tn21-like transposon backbone which comprised a Tn5036-like tnp transposition module at the IRi integron end and a Tn21 mer module at the IRt integron end. The parent integron/transposon that contributed the Tn5036 module was not related to Tn1696 since the integron insertion points in the transposon backbones were 16 bases apart. Examination of the other 20 class 1 integron-containing strains revealed further evidence of genetic exchange. This included a strain that possessed a Tn5036 module at the IRt end but not at the IRi end and another that possessed a tnp module beyond IRi that was a hybrid of Tn21 and Tn5051 and that is presumed to have arisen by site-specific recombination. This study highlights the ability of different genetic elements to act cooperatively to spread and rearrange antibiotic resistance in a community.

Mobilization of a Tn 402 -Like Class 1 Integron with a Novel Cassette Array via Flanking Miniature Inverted-Repeat Transposable Element-Like Structures

“…Four prawns, harvested from each of 16 distinct locations from Australia, the South Pacific, and Southeast Asia, were examined. More than 75% of mixed cultures from individual prawns tested positive for class 1 integrons with use of the primers HS915 and HS916 (15). PCR with these primers on pure isolates derived from such mixed cultures revealed that about 3% of 850 colonies were positive for a class 1 integron, a number consistent with findings of other studies (10,25).…”

Sequence of pR3521, an IncB Plasmid fromEscherichia coliEncoding ACC-4, SCO-1, and TEM-1 β-Lactamases

“…A mosaic sequence comprising ISKpn12, ISKpn11, aacC2, and a Tn2 transposon was located upstream of dbp. This region was highly homologous to a sequence carried by K. pneumoniae 12836 (15). The IRtnp repeat of Tn2 was adjacent to the remaining part of strB (strB*2).…”

Resistant plasmid profile analysis of multidrug resistant <i>Escherichia coli</i> isolated from urinary tract infections in Abeokuta, Nigeria

“…All the six isolates with the plasmids weight of 854bp were also resistance to cloxacillin, amoxicillin, ampicillin and cotrimoxazole. The emergence of R-plasmids in this study could be ascribed to the indiscriminate and widespread use of antibiotics caused by over-the-counter availability of antibiotics as well as the higher exposure of people to enteric flora in places with poor sanitation 25,39,55,56 . Clinical isolates of E. coli which showed multiple drug resistance were also found to harbour plasmids with molecular sizes ranging from 2kb to 6.5 kb and a maximum 26kb.…”