Systematic Survey of Vibrio spp. and Salmonella spp. in Bivalve Shellfish in Apulia Region (Italy): Prevalence and Antimicrobial Resistance

Abstract

The emergence of antimicrobial resistance (AMR) is increasingly common across the globe and aquatic ecosystems could be considered a reservoir of antibiotic-resistant bacteria. This study aimed to determine prevalence and antibiotic susceptibility of the potential pathogenic bacteria Salmonella spp. and Vibrio spp. in bivalve molluscs intended for human consumption, collected over a period of 19 months along the northern coast of Apulia region. The AMR profile was also determined in non-pathogenic Vibrio species, common natural inhabitants of seawater and a useful indicator for the surveillance of AMR in the environment. The current study presents data on the AMR of 5 Salmonella and 126 Vibrio isolates by broth microdilution MIC. Multidrug resistance (MDR) was observed in one S. Typhimurium strain towards sulfamethoxazole, trimethoprim, tetracycline, gentamicin, and ampicillin and in 41.3% of the Vibrio strains, mostly towards sulphonamides, penicillin, and cephems. All Vibrio isolates were sensitive to azithromycin, chloramphenicol, tetracycline, amoxicillin/clavulanic acid, gentamicin, streptomycin, amikacin, and levofloxacin. The AMR phenomenon in the investigated area is not highly worrying but not entirely negligible; therefore, in-depth continuous monitoring is suggested. Results concerning the antibiotic agents without available specific clinical breakpoints could be useful to upgrade the MIC distribution for Vibrio spp. but, also, the establishment of interpretative criteria for environmental species is necessary to obtain a more complete view of this issue.

Adriatic Sea Fishery Product Safety, Prospective and Climate Change

“…Additionally, 41.3% of the Vibrio strains displayed MDR, primarily against sulfonamides, penicillin, and cephem. However, all the tested Vibrio isolates demonstrated susceptibility to azithromycin, chloramphenicol, tetracycline, amoxicillin/clavulanic acid, gentamicin, streptomycin, amikacin, and levofloxacin [72].…”

Antimicrobial Resistance in Aquaculture: Risk Mitigation within One Health Context

“…The MICs for Vibrio spp. were examined in bivalve shellfish by Mancini et al [99] and it was observed that high resistance percentages to sulfonamide/sulfisoxazole (57.1%; 72/126) (MIC > 256 µg/mL), ampicillin (85.7%; 108/126), and cephalosporins/cefazolin (56.3%; 71/126) were found among all Vibrio species. In a study by de Oliveira et al [100] MIC assay based on the protocol by Clinical and Laboratory Standards Institute (CLSI, 2014) was used and provisional ECV for Streptococcus (agalactiae) in tilapia farming, evaluating the profile of florfenicol resistance, was established observing that ECV was 8 µg/mL for 94% of the tested strains classified as a wild-type; ECV was calculated using two methodologies: the normalized resistance interpretation (NIR) [101] and ECOFFinder MS (https://clsi.org/meetings/susceptibilitytesting-subcommittees/ecoffinder/).…”

Leveraging Plasma-Activated Seawater for the Control of Human Norovirus and Bacterial Pathogens in Shellfish Depuration

“…Vibrio spp. cause infections in humans via the oral route through the ingestion of contaminated water or raw or undercooked contaminated seafood (in particular, Vibrio parahaemolyticus and V. cholerae ) [ 28 , 29 ]. V. parahaemolyticus is the most common pathogen causing seafood-borne illnesses in many countries, and the strains harboring the tdh (encoding thermostable direct hemolysin) and trh (encoding tdh-related hemolysin) genes are pathogenic in humans [ 30 ].…”