A novel functional class 2 integron in clinical Proteus mirabilis isolates.
OBJECTIVE
To describe a novel functional class 2 integron that was found in clinical Proteus mirabilis isolates.


METHODS
Class 1 and 2 integrons were screened by PCR in 153 clinical Proteus isolates. The variable regions of class 1 and 2 integrons were determined by restriction analysis and sequencing. The mutations of internal stop codons in class 2 integrons and their common promoters were also determined by sequencing. Enterobacterial repetitive intergenic consensus (ERIC)-PCR was used to analyse the phylogenetic relations of class 2 integron-positive P. mirabilis isolates.


RESULTS
Class 1 integrons were detected in 96 (63%) of 153 Proteus isolates: eight different gene cassette arrays were detected, including dfrA32-ereA1-aadA2, which was detected for the first time in P. mirabilis. Class 2 integrons were detected in 101 (66%) of 153 Proteus isolates: four different gene cassette arrays were detected, including dfrA1-catB2-sat2-aadA1, which was detected for the first time in a class 2 integron. A novel functional class 2 integron was detected in 38 P. mirabilis isolates with a common promoter (-35 TTTAAT|16 bp|-10 TAAAGT). The variable region of this functional class 2 integron contained dfrA14 and three novel open reading frames with unknown functions. Very similar ERIC-PCR fingerprinting patterns were detected in these 38 P. mirabilis isolates and were different from other class 2 integron-positive isolates.


CONCLUSIONS
A novel functional class 2 integron was found for the first time in P. mirabilis. These functional class 2 integron-harbouring P. mirabilis isolates were likely to be clonally spread in our hospital.
Centre of Laboratory Medicine, Zhejiang Provincial People's Hospital, 158 Shangtang Road, Hangzhou 310014, China.
Quhao
Q
Wei
Qingfeng
Q
Hu
Shanshan
S
Li
Huoyang
H
Lu
Guoqiang
G
Chen
Beiqiong
B
Shen
Ping
P
Zhang
Yonglie
Y
Zhou
D018388:Codon, Terminator; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005838:Genotype; D006801:Humans; D032023:Integrons; D008969:Molecular Sequence Data; D058889:Molecular Typing; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D011401:Promoter Regions, Genetic; D011512:Proteus Infections / Q000382:microbiology*; D011513:Proteus mirabilis / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D017422:Sequence Analysis, DNA
D018388:Codon, Terminator; D004269:DNA, Bacterial
gene cassettes; horizontal gene transfer; integrases; recombination