Evidence and antibiotic resistance profiles of clinical Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) and non-ACB complex members in companion animals: A 2020-2022 retrospective study.

This research article presents the findings of a three-year retrospective study, examining the prevalence and antibiotic resistance profiles of Acinetobacter spp. strains in companion animals such as dogs, cats and horses. It contributes to the understanding of these bacterial strains as potential zoonotic pathogens and their resistance to certain common antibiotics.

Study Details and Procedure

In an attempt to determine the spread and antibiotic resistance profiles of Acinetobacter spp. in veterinary medicine, the researchers conducted a retrospective study covering the years 2020-2022. The species examined included both the Acinetobacter calcoaceticus-baumannii (ACB) and non-ACB complex.

• The data for the research was obtained from various clinical samples taken from dogs, cats, and horses.
• Each strain was identified by a process called MALDI-TOF MS identification, and their susceptibility to 11 types of antibiotics was tested using Kirby-Bauer and E-test methods.
• The researchers performed 628 bacteriological examinations during the study period and determined that 2.5% of these were positive for Acinetobacter genus strains.

Analysis and Results

When evaluating the results from in-visiting and hospitalized dogs, cats, and horses, frequencies of 2.3%, 1.9%, and 3% were obtained respectively. Members from the ACB-complex represented half of the isolates.

• All strains were found to be susceptible to aminoglycosides and polymyxins, meaning no pandrug-resistant species were recorded.
• While 12.5% of A. baumannii strains exhibited extensive drug resistance, a higher percentage of multidrug-resistant strains were found among non-ACB strains (35.5%) than ACB strains (25%).
• The susceptibility was similar in both groups, at 62.5%.
• The study also noted the different resistance patterns of the non-ACB species against antipseudomonal penicillins, III generation cephalosporins, and tetracyclines compared to those of ACB species.
• Carbapenem resistance was detected in 12.5% of XDR A. baumannii and significantly in 25% of MDR non-ACB complex members.

Significance and Implications

This research has two significant implications. First, they noted a presence of A. lactucae in two sick dogs in Italy, marking it as the first documented occurrence.

Second, the study helps highlight the role of non-ACB-complex species as important zoonotic pathogens. These could potentially become reservoirs of clinically relevant resistance profiles, posing a health risk.

The findings of this study contribute significantly towards improved understanding and management options for Acinetobacter spp. in pets and their potential transmission to humans.