Antimicrobial Resistance and Incidence of Integrons in Aeromonas Species Isolated from Diseased Freshwater Animals and Water Samples in Iran.

Reza Ranjbar,Hassan Sharifiyazdi,Reza Salighehzadeh

doi:10.3390/antibiotics8040198

Reza Ranjbar, Hassan Sharifiyazdi + Show 1 more

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https://doi.org/10.3390/antibiotics8040198

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Abstract

Aeromonas spp. is one of the major pathogens of freshwater animals. There has been little research on the genetics of antimicrobial resistance associated with it in Iranian aquaculture. To remedy this lack in research, 74 multi-drug-resistant Aeromonas spp. were isolated from farmed diseased carp, trout, sturgeon, ornamental fish, crayfish, and corresponding water samples and examined for genomic integron sequences. Class 1 integrons, containing seven types of integron cassette arrays (dfrA1-aadA1, dfrA1-orfC, dfrA12-aadA2, dfrA12-orfF-aadA2, dfrA15, dfrB4-catB3-aadA1, aac(6’)-Ib-cr-arr3-dfrA27) were found in 15% of the resistant isolates; no class 2 integrons were detected in any of the resistant isolates. As some tested isolates were resistant to more than two groups of antibiotics, our results demonstrated that freshwater animals in Iran could be a source of multiply drug-resistant Aeromonas spp. This finding suggests that the origin of the antimicrobial resistance of these animals be placed under increased surveillance in the future and that the use of antimicrobials be limited in aquaculture.

Highlights

Antimicrobial drugs are extensively used in animal husbandry and the aquaculture industry, and bacterial resistance to antibiotics is a harmful consequence of this practice
Mobile integrons encoding integrases are involved in the recombination of gene cassettes and participate mainly in the dissemination of antimicrobial resistance genes [3]
A variety of Gram-negative bacteria has been detected and the most common integron is the class 1 integron [4]. It has been proven by some researchers that this integron in Aeromonas species is primarily type 1 and transports different resistant gene cassettes

Summary

Introduction

Warm-blooded animals, as well as humans, are susceptible to diseases due to Aeromonas via polluted water or food [1]. Because of these diseases, antimicrobial drugs are extensively used in animal husbandry and the aquaculture industry, and bacterial resistance to antibiotics is a harmful consequence of this practice. Clonal selection or gene transfer is the main cause of resistance in bacteria. A variety of Gram-negative bacteria has been detected and the most common integron is the class 1 integron [4] It has been proven by some researchers that this integron in Aeromonas species is primarily type 1 and transports different resistant gene cassettes. Aminoglycoside resistance genes, i.e. aadA1, aadA2, and the trimethoprim resistance gene dfrA1, are the most prevalent resistance genes related to the class 1 integron [5]

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