Role of gut microbiota in dog and cat’s health and diseases

The role of companion animals in the spread of antimicrobial resistance (AMR) is still not well known. As part of a wider surveillance system, this study aimed to provide data about AMR in bacterial isolates from infections in companion animals referred to an Italian University Veterinary Hospital (VUH) from November 2020 to September 2022. A total of 940 isolates were identified with MALDI-TOF MS and subsequently the antimicrobial susceptibility test (AST) for 12 antimicrobials was performed. Urine was the most commonly submitted specimen (54.92%) and Escherichia coli was the most common bacterial species isolated (36.06%). Out of the 940 isolates, 747 (79.47%) were nonsusceptible to at least one drug (AMR), while 420 (44.68%) were considered multidrug resistant (MDR). The highest nonsusceptibility percentages were recorded for clindamycin (59.65 %), erythromycin (58.96 %), ampicillin (52.85%), and enrofloxacin (48.19%). Alarming percentages were recorded also for ceftiofur (25.51%), amoxicillin–clavulanate (22.99%), and piperacillin–tazobactam (15.85%). In multivariable risk factors analysis, previous use of invasive devices ( in both cases) and previous use of antimicrobials ( in both cases) were statistically related with higher AMR and MDR percentages. Apart from a general evaluation, the study focused on specific bacterial species (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) and specimens (blood cultures, urine from suspected healthcare-associated urinary tract infections, and surgical site infections), showing in both cases higher AMR and MDR percentages compared to average. These data highlight the urgency to further investigate AMR spread in pets and how passive surveillance systems can be effective tools to monitor AMR and to optimize antimicrobial use.

Bacterial urinary tract infections (UTIs) are common in small animal practice and their inappropriate treatment contributes to the antimicrobial resistance (AMR) spreading. This study assessed bacterial prevalence, non-susceptibility percentages, antimicrobial prescription and the impact of the application of international guidelines redacted by the International Society for Companion Animals Infectious Disease (ISCAID) in dogs and cats with UTIs evaluated at a European veterinary university hospital, over a 30-month period. A total of 729 bacterial isolates were included. The most frequently isolated bacterial species was Escherichia coli in both dogs (52.8%) and cats (45.7%). Following ISCAID guidelines, almost half of the cases were classified as upper UTIs (24.9%) or recurrent cystitis (24.8%). Multidrug resistance (MDR) percentage was 37.3% (n = 272). Over five semesters, MDR significantly decreased (p = 0.001). Additionally, a significant decrease was recorded for specimens from patients previously treated (p = 0.018) and under treatment at sampling (p < 0.001). Previous treatment with amoxicillin-clavulanate (p = 0.001), marbofloxacin (p < 0.001), enrofloxacin (p < 0.001) and piperacillin-tazobactam (p = 0.016) was linked with higher MDR rates. This study highlighted that companion animals are potential reservoirs for AMR; moreover, international guidelines applied in the daily practice guiding antimicrobial stewardship can lead to a reduction in AMR over time.

Multiple Sclerosis is a chronic neurological disease characterized by demyelination and axonal loss. This pathology, still largely of unknown etiology, carries within it a complex series of etiopathogenetic components of which it is difficult to trace the origin. An inflammatory state is likely to be the basis of the pathology. Crucial elements of the inflammatory process are the interactions between platelets and mast cells as well as the bacterial component of the intestinal microbiota. In addition, the involvement of mast cells in autoimmune demyelinating diseases has been shown. The present work tries to hang up on that Ariadne’s thread which, in the molecular complexity of the interactions between mast cells, platelets, microbiota and inflammation, characterizes Multiple Sclerosis and attempts to bring the pathology back to the causal determinism of psychopathological phenomenology. Therefore, we consider the possibility that the original error of Multiple Sclerosis can be investigated in the genetic origin of the depressive pathology.

Behavioral studies demonstrate that not only humans, but all other animals including dogs, can suffer from depression. A quantitative molecular evaluation of fatty acids in human and animal platelets has already evidenced similarities between people suffering from depression and German Shepherds, suggesting that domestication has led dogs to be similar to humans. In order to verify whether humans and dogs suffering from similar pathologies also share similar microorganisms at the intestinal level, in this study the gut-microbiota composition of 12 German Shepherds was compared to that of 15 dogs belonging to mixed breeds which do not suffer from depression. Moreover, the relation between the microbiota of the German Shepherd’s group and that of patients with depression has been investigated. The results indicate that the German Shepherd’s gut-microbiota has a different composition compared to other dog breeds and is characterized by microbial groups identified in humans with depression, highlighting the existence of a “core” microbiota associated with depression.

In small animal practice, blood cultures (BCs) are essential for diagnosing bacterial bloodstream infections (BSIs) and guiding targeted antimicrobial therapy, particularly in relation to the rise of multidrug-resistant (MDR) pathogens. This study analyzed 96 positive BCs from dogs and cats at the Veterinary University Hospital (VUH) of Bologna (2020–2024), assessing bacterial prevalence, antimicrobial resistance, and associated risk factors. Escherichia coli was the most common isolate (29/96), followed by Streptococcus canis (11/96). MDR percentage was 29.2% (28/96), with Gram-negatives associated with higher rates (p = 0.040). Nearly half of the cases (46.9%, 45/96) were suspected healthcare-associated infections (HAIs) significantly associated with the number of invasive devices used (p = 0.008) and with the absence of co-positive samples (p = 0.012). Empirical antibiotic therapy was administered in 94.8% (91/96) of cases, with ampicillin–sulbactam and marbofloxacin as the most used drugs. In vitro empirical therapy appropriateness was 76.9% (70/91). MDR was associated with inappropriate empirical therapy (p < 0.001). Mortality within 30 days was 36.5% (35/96), significantly linked to antibiotic escalation (p = 0.006). The findings highlight the need for systematic BC surveillance in veterinary settings to optimize treatment strategies (especially in countries with restrictions on antibiotic use in animals) to mitigate MDR spread and to protect public health.