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Characterization of Integrons and qnr Genes in Proteeae from a Teaching Hospital in China
Jianming Cao1, Meimei Li, Chunquan Xu
1Department of Microbiology and Immunology, School of Medicine, Xi'an Jiaotong University, Xi'an, China.
Background:
Proteeae isolates displaying multidrug-resistance (MDR) are the second most common causes of hospital-associated infections. The aim of this study was to screen class 1-3 integrons and plasmid-mediated quinolone resistance (PMQR) genes in Proteeae isolates from the First Affiliated Hospital of the Wenzhou Medical University.
Materials And Methods:
176 Proteeae isolates were collected from clinical specimens of inpatients between January 2011 and December 2013. Susceptibility testing was determined by the agar dilution method. Class 1-3 integrons and PMQR genes were amplified by polymerase chain reaction, and the variable regions of integrons were determined by restriction fragment length polymorphisms.
Results:
68.2% Proteeae isolates exhibited MDR phenotypes: 46.6 and 10.8% Proteeae isolates were positive for intI1 and intI2, respectively. The resistance rate of integron-positive isolates to aminoglycosides, fluoroquinolones, and trimethoprim/sulfamethoxazole was significantly higher than integron-negative isolates. Sequence analysis revealed that dfrA1-sat2-aadA1, dfrA1-catB2-sat2-aadA1, and sat2-aadA1 were first detected in Morganella morganii strains isolated from China. PMQR was determined by qnrD in 40 strains (22.7%).
Conclusion:
Our results indicate that class 1 and 2 integrons are common among Proteeae isolates. Meanwhile, qnrD are highly prevalent in Proteeae isolated from our hospital.
Insights
Multidrug-resistant Proteeae are common in hospitals. Class 1 and 2 integrons and the qnrD gene are prevalent, contributing to antimicrobial resistance in these clinical isolates.
Area of Science:
- Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Proteeae isolates are a significant cause of hospital-associated infections due to multidrug-resistance (MDR).
- Understanding the genetic basis of resistance in Proteeae is crucial for infection control.
Purpose of the Study:
- To screen for class 1-3 integrons and plasmid-mediated quinolone resistance (PMQR) genes in Proteeae isolates.
- To investigate the prevalence of these resistance mechanisms at the First Affiliated Hospital of Wenzhou Medical University.
Main Methods:
- Collected 176 Proteeae isolates from clinical specimens (2011-2013).
- Determined antimicrobial susceptibility using the agar dilution method.
- Amplified integrons and PMQR genes via PCR; analyzed integron variable regions using RFLP.
Main Results:
- 68.2% of Proteeae isolates showed MDR phenotypes.
- Class 1 integrase (intI1) and class 2 integrase (intI2) genes were detected in 46.6% and 10.8% of isolates, respectively.
- The qnrD gene conferring PMQR was found in 22.7% of strains; novel gene cassettes were identified in Morganella morganii.
Conclusions:
- Class 1 and 2 integrons are common in Proteeae isolates from this hospital.
- The qnrD gene is highly prevalent in Proteeae, contributing significantly to quinolone resistance.
- These findings highlight the importance of monitoring integrons and PMQR genes in clinical settings.
