Aeromonas species isolated from aquatic organisms, insects, chicken, and humans in India show similar antimicrobial resistance profiles

Abstract

Aeromonas species are Gram-negative bacteria that infect various living organisms and are ubiquitously found in different aquatic environments. In this study, we used whole genome sequencing (WGS) to identify and compare the antimicrobial resistance (AMR) genes, integrons, transposases and plasmids found in Aeromonas hydrophila, Aeromonas caviae and Aeromonas veronii isolated from Indian major carp (Catla catla), Indian carp (Labeo rohita), catfish (Clarias batrachus) and Nile tilapia (Oreochromis niloticus) sampled in India. To gain a wider comparison, we included 11 whole genome sequences of Aeromonas spp. from different host species in India deposited in the National Center for Biotechnology Information (NCBI). Our findings show that all 15 Aeromonas sequences examined had multiple AMR genes of which the Ambler classes B, C and D β-lactamase genes were the most dominant. The high similarity of AMR genes in the Aeromonas sequences obtained from different host species point to interspecies transmission of AMR genes. Our findings also show that all Aeromonas sequences examined encoded several multidrug efflux-pump proteins. As for genes linked to mobile genetic elements (MBE), only the class I integrase was detected from two fish isolates, while all transposases detected belonged to the insertion sequence (IS) family. Only seven of the 15 Aeromonas sequences examined had plasmids and none of the plasmids encoded AMR genes. In summary, our findings show that Aeromonas spp. isolated from different host species in India carry multiple AMR genes. Thus, we advocate that the control of AMR caused by Aeromonas spp. in India should be based on a One Health approach.

The mobile gene cassette carrying tetracycline resistance genes in Aeromonas veronii strain Ah5S-24 isolated from catfish pond sediments shows similarity with a cassette found in other environmental and foodborne bacteria

“…Other AMR genes detected included the cphA4 gene known to be intrinsically encoded in various Aeromonas spp. ( Dubey et al, 2022a , b ) as well as the colistin-resistance mcr-7.1 gene also reported from different Aeromonas spp. ( Dubey et al, 2022a , b ).…”

“…( Dubey et al, 2022a , b ) as well as the colistin-resistance mcr-7.1 gene also reported from different Aeromonas spp. ( Dubey et al, 2022a , b ). Despite so, the bla OXA-12 , bla FOX-7 , and mcr-7.1 genes detected in strain Ah5S-24 were not associated with integrases, recombinases or transposases suggesting that these genes could not be easily transferred or acquired from other bacteria species.…”

“…Several studies have shown that Aeromonas spp. intrinsically carry various bla OXA genes in their genomes that include the bla OXA-12 gene ( Dubey et al, 2022a , b ) previously detected in A. media , A. jandaei , A. sobria , A. dhakensis, and A. hydrophila ( Dubey et al, 2022a ; Rasmussen et al, 1994 ; Alksne and Rasmussen, 1997 ; Hilt et al, 2020 ; Huang et al, 2020 ) being in line with its presence in strain Ah5S-24 while bla FOX-7 previously reported in A. media and A. allosaccharophila was also found in strain Ah5S-24 ( Ebmeyer et al, 2019 ). Other AMR genes detected included the cphA4 gene known to be intrinsically encoded in various Aeromonas spp.…”

“…The high mortalities experienced in aquaculture have led to use of antibiotics, thereby contributing to increase of antimicrobial resistance (AMR) ( Roberts et al, 2006 ). As mentioned in our previous studies ( Dubey et al, 2022a , b ), the major limitation with most studies aimed at identifying AMR genes in bacteria is that they are mostly done by PCR that only detects AMR genes based on the primers used in the assay. This poses the risk of omitting important AMR genes whose primers are not included in PCR assays.…”

Cytotoxicity and Antimicrobial Resistance of Aeromonas Strains Isolated from Fresh Produce and Irrigation Water

“…However, the more cytotoxic strain AG29E1 did present potentially more important enzymes from the point of view of antimicrobial resistance. An increase in the resistance of some Aeromonas species was reflected in recent studies [ 9 , 50 , 51 , 52 ]. This should alert us to remain vigilant regarding the epidemiology of resistance markers in these species.…”