Animal drug shortages limit veterinary therapeutic options and introduce artifacts in antimicrobial sales reporting.

Supply chain issues disrupt veterinary care and cause downstream consequences that alter the practice of veterinary medicine. Antimicrobials are just 1 class of pharmaceuticals that have been impacted by supply chain issues over the last couple of years. Since February 2021, 2 sponsors/manufacturers of penicillin products have reported shortages in the active pharmaceutical ingredient.

Epidemiological Cutoff Values for Standard Broth Microdilution and Disk Diffusion Susceptibility Testing of Isolated from Fish.

and other closely related species cause motile aeromonad septicemia, a common fish disease. The disease affects many aquaculture sectors potentially requiring antimicrobial treatments. Therefore, researchers and laboratory diagnosticians need criteria called epidemiological cutoff values (ECVs) to determine whether a bacterial isolate has developed decreased susceptibility to an antimicrobial.

Epidemiological Cutoff Values for Standard Broth Microdilution Susceptibility Testing of Isolated from Fishes.

, the causative agent of columnaris disease in a large variety of freshwater fish, is a major problem in commercial aquaculture. A limited number of antimicrobial therapies are available to control this disease; therefore, these agents must be used judiciously. To facilitate effective monitoring for changes in susceptibility, the Clinical Laboratory Standards Institute (CLSI) has a standard broth microdilution test method specific for .

The AVMA's definitions of antimicrobial uses for prevention, control, and treatment of disease.

Recent state and federal legislative actions and current recommendations from the World Health Organization seem to suggest that, when it comes to antimicrobial stewardship, use of antimicrobials for prevention, control, or treatment of disease can be ranked in order of appropriateness, which in turn has led, in some instances, to attempts to limit or specifically oppose the routine use of medically important antimicrobials for prevention of disease. In contrast, the AVMA Committee on Antimicrobials believes that attempts to evaluate the degree of antimicrobial stewardship on the basis of therapeutic intent are misguided and that use of antimicrobials for prevention, control, or treatment of disease may comply with the principles of antimicrobial stewardship. It is important that veterinarians and animal caretakers are clear about the reason they may be administering antimicrobials to animals in their care.

Comparative Phenotypic and Genotypic Analysis of Edwardsiella Isolates from Different Hosts and Geographic Origins, with Emphasis on Isolates Formerly Classified as E. tarda, and Evaluation of Diagnostic Methods.

spp. are responsible for significant losses in important wild and cultured fish species worldwide. Recent phylogenomic investigations have determined that bacteria historically classified as actually represent three genetically distinct yet phenotypically ambiguous taxa with various degrees of pathogenicity in different hosts.

Zebrafish Sensitivity to Botulinum Neurotoxins.

Botulinum neurotoxins (BoNT) are the most potent known toxins. The mouse LD50 assay is the gold standard for testing BoNT potency, but is not sensitive enough to detect the extremely low levels of neurotoxin that may be present in the serum of sensitive animal species that are showing the effects of BoNT toxicity, such as channel catfish affected by visceral toxicosis of catfish. Since zebrafish are an important animal model for diverse biomedical and basic research, they are readily available and have defined genetic lines that facilitate reproducibility.

Efficacy of Florfenicol for Control of Mortality Associated with Edwardsiella ictaluri in Three Species of Catfish.

The efficacy of florfenicol for control of mortality associated with Edwardsiella icatluri was studied in fingerlings of Channel Catfish Ictalurus puntatus (Delta strain), Blue Catfish I. furcatus (D&B strain), and a hybrid catfish (Delta strain Channel Catfish × D&B strain Blue Catfish). On day 0, fish were immersion challenged in 65-L aquaria.

The effects of a sublethal dose of botulinum serotype e on the swimming performance of channel catfish fingerlings.

Abstract Visceral toxicosis of catfish (VTC) is a disease of cultured Channel Catfish Ictalurus punctatus in the Mississippi Delta region and surrounding states. The etiology of VTC is associated with botulinum serotype E (BoNT/E), which causes blockage of acetylcholine release at the neuromuscular junction, leading to weakness and paralysis of skeletal muscles (including those involved in swimming). This study attempted to determine if sublethal exposure to purified BoNT/E caused reductions in swimming performance and metabolism of Channel Catfish.

Lactococcosis in Silver Carp.

An adult Silver Carp Hypophthalmichthys molitrix with a focally extensive skin lesion near the caudal peduncle and mild iridial hemorrhage was submitted to the Aquatic Research and Diagnostic Laboratory (ARDL) in Stoneville, Mississippi, as part of a fish kill investigation. Touch impressions of this musculoskeletal lesion revealed small cocci (∼1 μm) in pairs or chains within an inflammatory milieu. A pure Gram-positive cocci isolate was obtained from the brain, while cultures of the kidney and muscle yielded multiple bacterial colony types, including the Gram-positive cocci seen in the brain.

Edwardsiella piscicida identified in the Southeastern USA by gyrB sequence, species-specific and repetitive sequence-mediated PCR.

A new Edwardsiella taxon was recently described from fishes of Europe and Asia. Phenotypically similar to E. tarda, extensive genetic and phenotypic characterization determined this new strain does not belong to any established Edwardsiella taxa, leading to the adoption of a new taxon, E.

Quality control ranges for testing broth microdilution susceptibility of Flavobacterium columnare and F. psychrophilum to nine antimicrobials.

A multi-laboratory broth microdilution method trial was performed to standardize the specialized test conditions required for the fish pathogens Flavobacterium columnare and F. psychrophilum. Nine laboratories tested the quality control (QC) strains Escherichia coli ATCC 25922 and Aeromonas salmonicida subsp.

Determination of the median lethal dose of botulinum serotype E in channel catfish fingerlings.

The median lethal dose of botulinum serotype E in 5.3-g channel catfish Ictalurus punctatus fingerlings was determined. Five tanks (five fish/tank) were assigned to each of the following treatment groups: 70, 50, 35, 25, or 15 pg of purified botulinum serotype E.

The pathology associated with visceral toxicosis of catfish.

Visceral toxicosis of catfish (VTC) syndrome was recognized in the late 1990 s and recently has been associated with exposure to Clostridium botulinum type E neurotoxin. Tentative diagnosis is based on clinical presentation and gross findings, and is confirmed by bioassay. In April 2009, channel catfish (Ictalurus punctatus) from 2 different farms presented with abnormal swimming behavior and mortalities.

Determination of florfenicol dose rate in feed for control of mortality in Nile tilapia infected with Streptococcus iniae.

A dose titration study was conducted to determine the dosage of florfenicol (FFC) in feed to control Streptococcus iniae-associated mortality in Nile tilapia Oreochromis niloticus. Six tanks were assigned to each of five treatments: (1) not challenged with S. iniae and fed unmedicated feed; (2) challenged with S.

Efficacy of florfenicol for control of mortality caused by Flavobacterium columnare infection in channel catfish.

The studied in channel catfish Ictalurus punctatus fingerlings held in 80-L aquaria. Nonabraded fish were challenged by immersion on day 0. Thirty 80-L tanks were randomly assigned in equal numbers to two treatment groups, one in which fish were fed a commercial diet without florfenicol (unmedicated feed) and one in which they were fed a diet containing 10 mg of florfenicol/kg of body weight (medicated feed) for ten consecutive days.

New data on Henneguya pellis (Myxozoa: Myxobolidae), a parasite of blue catfish Ictalurus furcatus.

The original description of Henneguya pellis, a myxozoan parasitizing blue catfish Ictalurus furcatus, is supplemented with new data on histopathology, spore morphology, and 18S small subunit (SSU) ribosomal DNA (rDNA) sequence. Plasmodia presented as both internal and external, raised, cyst-like lesions on the body wall of the peritoneal cavity and on the skin. The cysts contained numerous elongate, lanceolate myxospores, flattened parallel to the suture line.

Detection of botulinum type E toxin in channel catfish with visceral toxicosis syndrome using catfish bioassay and endopep mass spectrometry.

Visceral toxicosis of catfish (VTC) is a syndrome characterized by sudden mortality in apparently healthy market- and brooder-sized catfish (Ictalurus punctatus). This paper reports the design of a catfish neutralization assay to detect botulinum in catfish with VTC and verification by Endopep mass spectrometry (Endopep-MS). Sera from 6 affected catfish were incubated with botulinum antitoxin serotypes A, B, C, D, E, or F.

Gastrointestinal torsion in a channel catfish (Ictalurus punctatus).

A case of gastrointestinal torsion with dilatation in a farm-raised channel catfish (Ictalurus punctatus) was examined at the Thad Cochran National Warmwater Aquaculture Center (Stoneville, Mississippi, USA). The affected fish was a gravid female broodfish, which displayed pale gills and a markedly distended abdomen. Internal examination revealed that the gastrointestinal tract and ovaries were rotated around each other four times in a counterclockwise direction as viewed in right lateral recumbency.