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Screening Foodstuffs for Class 1 Integrons and Gene Cassettes
Published on: June 19, 2015
A novel functional class 2 integron in clinical Proteus mirabilis isolates
Quhao Wei1, Qingfeng Hu, Shanshan Li
1Centre of Laboratory Medicine, Zhejiang Provincial People's Hospital, 158 Shangtang Road, Hangzhou 310014, China.
Objectives:
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.
Insights
A novel functional class 2 integron was discovered in clinical Proteus mirabilis. This finding suggests these integron-harboring bacteria may be spreading clonally within hospitals.
Area of Science:
- Microbiology
- Genetics
- Antimicrobial Resistance
Background:
- Integrons are genetic platforms that capture and express gene cassettes, contributing to antimicrobial resistance.
- Class 1 and Class 2 integrons are commonly found in clinical bacteria, including Proteus species.
- Understanding integron diversity is crucial for tracking the spread of antibiotic resistance genes.
Purpose of the Study:
- To identify and characterize novel integron structures in clinical isolates of Proteus mirabilis.
- To investigate the prevalence and genetic relatedness of Proteus mirabilis isolates carrying class 2 integrons.
Main Methods:
- Screening of 153 clinical Proteus isolates for class 1 and class 2 integrons using PCR.
- Determination of integron variable regions via restriction analysis and sequencing.
- Phylogenetic analysis of integron-positive isolates using Enterobacterial Repetitive Intergenic Consensus (ERIC)-PCR.
Main Results:
- Class 1 integrons were found in 63% of isolates, with eight gene cassette arrays identified, including a novel array in P. mirabilis.
- Class 2 integrons were detected in 66% of isolates, with four arrays found, including a novel array in a class 2 integron.
- A novel functional class 2 integron, containing dfrA14 and three novel open reading frames, was identified in 38 P. mirabilis isolates with similar ERIC-PCR patterns, suggesting clonal spread.
Conclusions:
- A novel functional class 2 integron was identified for the first time in Proteus mirabilis.
- The identified Proteus mirabilis isolates harboring this novel class 2 integron appear to be clonally disseminated within the hospital environment.
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