Dissemination of insertion sequence common regions 1 and int1 gene and drug resistance of 483 Escherichia coli and Klebsiella pneumonia broiler isolates

Abstract

Objective: To investigate and analyze distribution characteristics of two multidrug resistance related genes in broiler isolates in Shandong province. Methods: The pre slaughter broilers were chosen from Shandong province in this study in June, 2014. A total of 400 fecal samples from five different zones (east, south, west, north and middle) of the hen house were collected. 373(77.2%) Escherichia coli and 110 (22.8%) Klebsiella pneumonia strains were isolated, and ISCR1 and int1 gene were detected by PCR assay and sequencing. The resistance to 10 drugs belonging to 8 classes antimicrobial drugs were obtained by using minimal broth dilution method and data analysis. The difference between isolates and drug resistance profiles was analyzed. Results: Among 483 isolates, 440 isolates (91.1%), 126 isolates (26.1%) and 126 isolates (26.1%) were detected as int1, ISCR1 and both two gene carriers, respectively. The rate of 37 E. coli isolates not carried ISCR1 or int1 gene resistant to 0 to 2, 3 to 5, 6 to 8 classes antimicrobial agents was 13.5% (n=5), 78.4% (n=29), and 8.1% (n=3), respectively; the rate of 288 only int1 gene E. coli carriers resistant to 0 to 2, 3 to 5, 6 to 8 groups antimicrobial agents was 2.4% (n=7), 74.7% (n=215), and 22.9% (n=6), respectively. The data above showed significant difference (P<0.001). The rate of 26 only int1 gene K. pneumonia carriers resistant to 0 to 2, 3 to 5, 6 to 8 classes antimicrobial agents was 11.5% (n=3), 76.9% (n=20), and 11.5% (n=3), respectively; the rate of 78 both two gene K. pneumonia carriers resistant to0 to 2, 3 to 5, 6 to 8 groups antimicrobial agents was 0, 35.9% (n=28), and 64.1% (n=50), respectively. The data above showed significant difference (P<0.001). Conclusion: Gene int1 and ISCR1 showed high prevalence in E. coli and K. pneumonia isolates. High level multi-drug resistance profile could be mediated by int1 and ISCR1 gene co-existence.