Antimicrobial Resistance in Bacteria Isolated From Canine Urine Samples Submitted to a Veterinary Diagnostic Laboratory, Illinois, United States

Prevalence and antimicrobial resistance of bacteria isolated from urine samples of cats with urinary tract infections in Illinois, United States of America

Information on antimicrobial resistance patterns of urinary pathogens of cats can aid veterinarians in their antimicrobial prescription choices. We assessed the prevalence and antimicrobial resistance of bacteria isolated from urine samples of cats with urinary tract infections (UTIs) submitted to a veterinary diagnostic laboratory in Illinois between 2020 and 2022. The laboratory received 2026 urine samples during the study period, of which 606 (29.97%) showed bacterial growth, and from these samples, 883 bacterial strains were recovered. The most common gram-positive bacterial species included Enterococcus faecalis (n = 123), Staphylococcus felis (n = 50), and Staphylococcus pseudintermedius (n = 28), while the most common gram-negative bacteria included Escherichia coli (n = 322) and Proteus mirabilis (n = 18). Among the gram-positive isolates, none of the Enterococcus faecalis isolates showed resistance to amoxicillin-clavulanic acid and ampicillin. In addition, Staphylococcus felis isolates showed low resistance to ampicillin (7.32%), enrofloxacin (4.88%), and amoxicillin-clavulanic acid (4.88%). Among gram-negative bacteria, E. coli isolates showed a high resistance to ampicillin (30.64%), and a moderate resistance to amoxicillin-clavulanic acid (11.78%) and cefovecin (11.11%), antibiotics considered as first-line choices to treat UTIs in cats. Compared to 2020, the rate of E. coli isolates resistant to amoxicillin-clavulanic acid was lower in 2022 (IRR: 0.42; 95%; CI: 0.18-0.99). This study provides antibiograms of common feline urinary pathogens in Illinois that could aid veterinarians in their empirical UTI therapy choices. Requesting an antimicrobial susceptibility test when starting an empirical treatment could be beneficial to guide altered therapy to secure treatment success if the causative pathogens are resistant to the empirical antimicrobial choices.

Resistance Genes and Virulence Factor Genes in Coagulase-Negative and Positive Staphylococci of the Staphylococcus intermedius Group (SIG) Isolated from the Dog Skin

Staphylococci are common pathogens in dogs, causing a variety of dermatological problems. This study aimed to characterize the prevalence, antibiotic resistance, and biofilm-forming potential of Staphylococcus species isolated from the skin of shelter dogs. Overall, 108 samples were collected from the hairless skin areas of dogs in a shelter over one year. Isolates were cultured using standard microbiological methods and identified through biochemical testing, MALDI-TOF MS, and multiplex PCR. A total of 67 Staphylococcus isolates were identified, with S. pseudintermedius being the most prevalent. Antibiotic susceptibility was assessed using disk diffusion and MIC methods, revealing high resistance to ampicillin, erythromycin, and tetracycline. Notably, 12 multidrug-resistant SIG (S. intermedius group; S. pseudintermedius) and 4 CoNS strains (coagulase-negative staphylococci; S. equorum) were identified. Biofilm production was evaluated using a crystal violet assay, showing variable biofilm-forming capabilities among isolates and PCR, to confirm genes associated with biofilm formation. These findings highlight the presence of multidrug-resistant Staphylococcus species in shelter dogs, emphasizing the need for careful monitoring and antibiotic stewardship to manage potential risks to both animal and human health.

Prevalence and Virulence Profiles of Klebsiella pneumoniae Isolated From Different Animals

BACKGROUND

Klebsiella pneumoniae liver abscess (KLA) is an invasive disease, and the occurrence of infection is related to its virulence factors and colonization of the host's gastrointestinal (GI) tract. Some animal-sourced isolates share virulence factors with human pathogens. However, the potential of K. pneumoniae as a zoonotic agent has not been confirmed in murine infection model.

OBJECTIVES

To identify the prevalence and virulence profiles of K. pneumoniae colonization in companion and wild animals and subsequently determine the pathogenicity of selected strains.

METHODS

Forty-five K. pneumoniae isolates (45/302) were obtained from faeces of companion or wild animals. Virulence factors, gyrA polymerase chain reaction with the restriction fragment length polymorphism (PCR-RFLP) and pulsed field gel electrophoresis (PFGE) were detected and compared with our previous collection of 60 human pathogens. For KLA model and cytotoxicity test, three animal-sourced isolates, CHKP0009 (snake, K1, KpII), CHKP0021 (turtle, K2, pLVPK, KpI, cluster I) and CHKP1027 (dog, non-K1/K2, HV, KpI, cluster III), with similar genotype and/or phenotype to human pathogens were selected and evaluated for their virulence with human hypervirulent K. pneumoniae (hvKp) CG43S.

RESULTS

The prevalence of K. pneumoniae was higher in companion than wild animals. K. pneumoniae was primarily isolated from dogs, turtles and snakes. Some animal-sourced isolates carried virulence factors and revealed phylogenetic relatedness with human pathogens. In KLA model, BALB/c mice infected with snake isolate CHKP0009 and dog isolate CHKP1027 survived for 14 days but showed significant bacterial loads in the liver and spleen. Notably, the pet turtle isolate CHKP0021 presented comparable virulence with human hvKp CG43S and induced liver abscess formation. All three selected animal-sourced isolates could colonize in the GI tract and possess cytotoxic ability. These findings demonstrated pathogenicity of the animal K. pneumoniae isolates. In addition, the high prevalence of K. pneumoniae in companion animals and some isolates with virulence profiles suggested animal-sourced K. pneumoniae has the zoonotic potential to cause human disease.

CONCLUSION

Animals are the natural hosts of zoonotic pathogens. Some animal-sourced K. pneumoniae isolates are not only pathogenic in vivo but also exhibit phylogenetic relatedness to human pathogens, suggesting the existence of a zoonotic risk for K. pneumoniae between these two populations.

Impact of Antimicrobial Resistance of Pseudomonas aeruginosa in Urine of Small Companion Animals in Global Context: Comprehensive Analysis

The isolation of multidrug-resistant (MDR) bacteria from the urinary tracts of pets is increasingly common, particularly in animals with concurrent health conditions. Pseudomonas aeruginosa (PA) is one of the most significant antimicrobial-resistant bacteria affecting cats and dogs within the European Union (EU). This study aims to review the prevalence and antimicrobial resistance patterns of PA isolated from urine samples of small animals globally. This pathogen is known for its opportunistic infections and is a significant concern in veterinary medicine due to its inherent resistance to multiple antibiotics and its ability to acquire additional resistance mechanisms. This review seeks to enhance educational initiatives regarding the management of emerging MDR bacteria.

Monitoring the potential dissemination of antimicrobial resistance in foods, environment, and clinical samples: a one health prospective

Circulation of antimicrobial resistant (AMR) bacteria in the environment, animals, and humans is a major concern. Food chain is an important link to spread AMR across the biosphere. Global warming, preserved and fast foods availability, random use of un-prescribed antimicrobials, unplanned bio-waste management, and using high doses of antibiotics and bio-fertilizers to agricultural fields and animal farms, increase the threat of spreading AMR bacteria. Current study reports prevalence of AMR in enteric pathogens isolated from food, food handlers, environment, and diarrheal patients. The incidence data on AMR pathogens were collected from Assam, Sikkim, Tripura, and Arunachal Pradesh, India, through a well-structured market and hospital surveillance. There  were 428 (3.0%) enteric pathogens detected in food and 184 (5.3%) in clinical samples. Most of the pathogens were resistant (70-100%) to commonly used antimicrobials in treatment of diarrheal infection. Result showed a spread of AMR across food chain, underscoring need for swift preventive intervention.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01676-z.

Antimicrobial Resistance and Biofilm-Forming Ability in ESBL-Producing and Non-ESBL-Producing Escherichia coli and Klebsiella pneumoniae Isolated from Canine Urinary Samples from Italy

Background: In dogs, bacterial urinary tract infections are a frequent cause of antimicrobial prescription, increasing the risk of selecting antibiotic-resistant bacteria. This study analyzed resistance patterns, the presence of extended-spectrum β-lactamases (ESBLs) and biofilm-forming capacity in E. coli and K. pneumoniae previously isolated from urine samples collected from 133 selected dogs admitted to the Veterinary Teaching Hospital of Milan, Italy, in 2021 and 2023. Methods: The E. coli and K. pneumoniae isolates were bacteriologically and genetically analyzed. Results: Overall, 53/133 (39.8%) samples had a positive microbiological culture. Thirty-four E. coli/K. pneumoniae isolates were detected, accounting for 26.5% of the examined samples. The 34 isolates included 28 E. coli and 6 K. pneumoniae. Four (11.8%) were ESBL-producing bacteria, all supported by blaCTX-M gene belonging to group 1. The K. pneumoniae isolates were significantly associated with ESBL production (p < 0.05). MIC analysis showed 11 (32.4%) multidrug-resistant isolates. Biofilm-forming capacity was observed in 23 (67.6%) isolates, regardless of bacterial species, including 20 weakly and 3 moderately adherent bacteria. All moderate biofilm producers were K. pneumoniae. Multidrug resistance (MDR) was significantly more present in strains with moderate biofilm-forming ability compared to strains with weak ability to form biofilm (p < 0.05). E. coli was confirmed as the most commonly identified urinary isolate in dogs. Conclusions: The high presence of ESBL producers and MDR in K. pneumoniae suggests mandatory in vitro susceptibility testing in the presence of this bacterium in dogs with UTI. The association of moderate biofilm production with MDR highlights the need for monitoring and surveillance of bacterial prevalence and resistance patterns of urinary isolates in dogs.

Assessing Illinois companion animal veterinarians' antimicrobial prescription practices and the factors that influence their decisions when treating bacterial infections in dogs and cats

AIMS

Judicious antimicrobial use in companion animal practice is critical for maintaining the effectiveness of antimicrobial agents against bacterial infections and reducing the selection of antimicrobial-resistant bacteria. This study aimed to provide insights into companion animal veterinarians' antimicrobial treatment recommendations for common bacterial infections in dogs and cats and describe the factors influencing their prescription choices.

METHODS AND RESULTS

An online survey using QualtricsXM® software was administered between September and November 2022 to companion animal veterinarians who were Illinois State Veterinary Medical Association members. Descriptive and text analyses were conducted to assess the participants' responses. A total of 78 surveys were included in the analysis. Skin infections were ranked as the most common bacterial infections for which veterinarians prescribed antimicrobial agents, followed by ear, urinary tract, respiratory, and enteric infections. The severity of clinical symptoms and the results of bacterial culture and susceptibility tests were the most influential factors for veterinarians when making antimicrobial prescription choices. Veterinarians were aware of the current antimicrobial prescription guideline recommendations when prescribing antimicrobials empirically to nine hypothetical scenarios of bacterial infections. According to the results of the text analysis that assessed veterinarians' responses to an open-ended question, regarding their challenges when prescribing antimicrobial agents, the pairwise correlation of word frequencies within each response showed the highest correlations between the words 'owner' and 'compliance', 'administration' and 'route', 'cost' and 'culture', and 'patients' and 'acceptance'.

CONCLUSIONS

The study results can support animal health stakeholders in the development of antimicrobial stewardship programmes to promote appropriate antimicrobial use and limit the emergence of antimicrobial resistance.

Diagnostic ultrasonography and antimicrobial resistance of different pathogens associated with canine and feline lower urinary tract disorders

There is a significant issue concerning the dissemination of antimicrobial-resistant bacteria within companion animals. Urinary tract infections (UTIs) are a common problem in veterinary medicine for which empirical antibiotics are utilized. This study aimed to investigate the antimicrobial resistance of different uropathogens associated with UTIs in canine and feline cases. A total of 146 dogs and 162 cats suffered from lower urinary tract disorders were subjected to ultrasonographic and microbiological examination. Cystitis, urinary sediment, and cystic calculi are the most common ultrasonographic abnormalities associated with bacterial UTIs. Bacterial UTIs were obtained in 36.98 % and 25.92 % of cases in dogs and cats, respectively. A low rate of mixed infection was detected in canine cases (3.7 %). E. coli was the most prevalent pathogen isolated from 46.4 % and 66.7 % of canine and feline isolates, respectively followed by Proteus spp. in canine isolates (16.1 %) and Klebsiella spp. in feline isolates (14.3 %). Staphylococcus spp. was isolated from canine cases only with the detection of methicillin-resistant Staphylococcus pseudintermedius (MRSP) strains at 3.6 %. The majority of the isolated strains were resistant to various antibiotic classes, particularly β-lactams. All gram-negative bacteria were susceptible to amikacin, whereas gram-positive strains exhibited 100 % sensitivity to nitrofurantoin and linezolid. Different bacterial species displayed low resistance to carbapenems and fluoroquinolones. Multi-drug resistance was reported in canine and feline strains at 64.3 % and 54.8 %, respectively. These findings prove the crucial necessity to restrict antibiotic consumption depending on urine culture and antibiotic sensitivity tests.

Mitigating antimicrobial resistance, an approach to stewardship in canine urinary tract infection

Urinary tract infection (UTI) caused by antimicrobial resistant bacteria is common in dogs leading to serious health impact in pet animal as well as on human health. Understanding the prevalent uropathogens and their drug susceptibility is essential for limiting the antimicrobial resistance through implementation of stewardship policies. In view of this, present study was envisaged to determine the prevalent bacterial uropathogens and their antibiogram from clinical cases of canine UTI. Urine samples were collected from 35 dogs presented with clinical signs of UTI and a total of 27 bacterial isolates were recovered. Among that Escherichia coli was the most predominant isolate followed by Klebsiella aerogenes, Staphylococcus aureus, Proteus mirabilis, Enterococcus sp. and Citrobacter freundii. All isolates were found resistant to one or more 1st line antibiotics recommended by consensus guidelines and 70% of total isolates showed multidrug resistance. Additionally, this study evaluated the weightage of empirical therapy as per the consensus guidelines over antimicrobial susceptibility test guided treatment. Dogs with uncomplicated UTI were selected and categorized into three different groups (n = 6). Group 1 was treated with common empirical choice amoxycillin-clavulanic acid and dogs showed susceptible to ciprofloxacin were kept in Group 2 and treated with ciprofloxacin along with urinary alkalizer disodium hydrogen citrate. Nitrofurantoin susceptible cases were kept in Group 3 and treated with a combination of nitrofurantoin and urinary acidifier ammonium chloride. Therapeutic outcome was evaluated and success rate was higher in Group 2 and 3 than Group 1 suggested that selection of antibiotics with the use of local or institutional antibiogram data is more considerate than acknowledged international guidelines in the existing situation.

The Antimicrobial Effect of Cornus mas L. and Sorbus aucuparia L. Fruit Extracts against Resistant Uropathogens in Correlation with the Prevalence of Urinary Tract Infections in Companion Animals

Urinary tract infections (UTIs) are a widespread condition in pets, with many antibiotics being prescribed, contributing to the rise in antimicrobial resistance, which is a worldwide threat. This study's main objective was to analyze the in vitro antimicrobial activity of Cornus mas and Sorbus aucuparia fruit hydro-ethanolic extracts towards bacteria identified in the urine of companion animals experiencing UTIs. Urine samples were collected from dogs and cats (n = 83; 47 negative, 36 positive); several bacterial strains were identified (n = 49) belonging to the Escherichia, Enterococcus, Staphylococcus, Proteus, Klebsiella, Enterobacter, Pseudomonas, Acinetobacter, Leclercia, and Kocuria genera. Bacterial susceptibility was tested using the disk diffusion method, with the majority being resistant to several beta-lactams, quinolones, trimethoprim/sulfamethoxazole, and nitrofurantoin. Subsequently, 13 resistant isolates were selected to evaluate the fruits extracts' antimicrobial potential using the agar well diffusion and broth microdilution methods. Cornus mas exhibited the greatest activity against Gram-negatives (primarily Pseudomonas luteola), while Sorbus aucuparia showed maximum effects towards Gram-positives (particularly Enterococcus faecalis). The MIC was 0.01 μg/μL for both extracts; the MBC was 0.08 μg/μL for Cornus mas and 0.05 μg/μL for Sorbus aucuparia. However, Cornus mas showed a stronger bactericidal effect. This is the first study to investigate these fruit extracts in UTI isolates of companion animals, and these extracts might be used as substitutes or adjuvants for antibiotics, thus contributing to a reduction in antimicrobial resistance.

Antimicrobial Susceptibility of Canine and Feline Urinary Tract Infection Pathogens Isolated from Animals with Clinical Signs in European Veterinary Practices during the Period 2013-2018

Bacterial urinary tract infections (UTIs) occur frequently in companion animals and are often treated with antibiotics. However, antimicrobial resistance can severely hamper treatment success. Therefore, antimicrobial susceptibility monitoring is key. UTI isolates were obtained from dogs and cats in two collection periods (ComPath II: 2013-2014 and ComPath III: 2017-2018) as part of CEESA's ComPath programme. Susceptibility testing of the UTI isolates (2021 in total) was carried out at one central laboratory using agar and broth dilution methodology as recommended by the Clinical and Laboratory Standards Institute. Escherichia coli was the most frequently isolated bacterium in UTI in both dogs (46.9%, 43.1%) and cats (61.2%, 48.3%) across ComPath II and ComPath III, respectively. The percentage of resistance in E. coli was low (<10%) across both programmes in both dogs and cats except for trimethoprim-sulfamethoxazole (dogs ComPath III: 12.9%; cats ComPath II: 13.0%) and enrofloxacin (10.5%), marbofloxacin (11.4%), and doxycycline (98.8%) for dogs in ComPath III. Three (7.5%) of the 40 isolated S. aureus bacteria in total were MRSA and harboured mecA. The level of multidrug resistance (MDR) was generally low and ranged from 0.0% for feline coagulase-negative Staphylococcus spp. to 11.7% for canine Proteus spp., except for a peak of MDR observed in canine Klebsiella isolates from ComPath II (36.7%). Overall, antimicrobial resistance for most canine and feline UTI pathogens isolated during the ComPath II and ComPath III programmes was low (1-10%) to moderate (10-20%).

Multidrug resistance in pathogenic Escherichia coli isolates from urinary tract infections in dogs, Spain

Escherichia coli (E. coli) is a pathogen frequently isolated in cases of urinary tract infections (UTIs) in both humans and dogs and evidence exists that dogs are reservoirs for human infections. In addition, E. coli is associated to increasing antimicrobial resistance rates. This study focuses on the analysis of antimicrobial resistance and the presence of selected virulence genes in E. coli isolates from a Spanish dog population suffering from UTI. This collection of isolates showed an extremely high level of phenotypic resistance to 1st-3rd generation cephalosporins, followed by penicillins, fluoroquinolones and amphenicols. Apart from that, 13.46% of them were considered extended-spectrum beta-lactamase producers. An alarmingly high percentage (71.15%) of multidrug resistant isolates were also detected. There was a good correlation between the antimicrobial resistance genes found and the phenotypic resistance expressed. Most of the isolates were classified as extraintestinal pathogenic E. coli, and two others harbored virulence factors related to diarrheagenic pathotypes. A significant relationship between low antibiotic resistance and high virulence factor carriage was found, but the mechanisms behind it are still poorly understood. The detection of high antimicrobial resistance rates to first-choice treatments highlights the need of constant antimicrobial resistance surveillance, as well as continuous revision of therapeutic guidelines for canine UTI to adapt them to changes in antimicrobial resistance patterns.

In Vitro Activity of Allium cepa Organosulfur Derivatives against Canine Multidrug-Resistant Strains of Staphylococcus spp. and Enterobacteriaceae

BACKGROUND

The increase of multi-resistant bacteria, especially Staphylococcus spp. and Enterobacteriaceae, constitutes a challenge in veterinary medicine. The rapid growth of resistance is outpacing antibiotic discovery. Innovative strategies are needed, including the use of natural products like Allium species (Allium sativum L. and Allium cepa L.), which have been used empirically for centuries to treat infectious diseases in humans and farm and aquaculture animals due to their antibacterial properties.

METHODS

This study aimed to evaluate the in vitro activity of two Allium-derived compounds, propyl propane thiosulfinate (PTS) and propyl propane thiosulfonate (PTSO), against multi-resistant Staphylococcus spp. (n = 30) and Enterobacteriaceae (n = 26) isolated from dogs referred to a veterinary teaching hospital in Madrid.

RESULTS AND DISCUSSION

The results indicated the in vitro efficacy of PTSO/PTS against the tested bacterial strains, and 56.7% of Staphylococcus pseudintermedius and 53.8% of Enterobacteriaceae showed sensitivity to PTS and PTSO compared with classic antibiotics. In addition, 50% of S. pseudintermedius strains resistant to erythromycin, ibofloxacin, difloxacin and orbifloxacin and 50% of Enterobacteriaceae strains resistant to tetracycline and doxycycline were sensitive to PTS and PTSO. Although studies are needed to verify their efficacy in vivo, the combined use of PTS and PTSO exhibits promise in enhancing bacterial sensitivity against S. pseudintermedius and Enterobacteriaceae infections, providing a first insight into the potential of both compounds in veterinary practice.

PK-PD integration of enrofloxacin and cefquinome alone and in combination against Klebsiella pneumoniae using an in vitro dynamic model

Introduction: Klebsiella pneumoniae is classified as a critical pathogen in both animals and humans and infections can be fatal in chickens resulting in substantial economic losses. However, the misuse of antibiotics can also lead to drug resistance and a potential transmission chain between animals and humans. Three K. pneumoniae strains with different susceptibility phenotypes were chosen to study the pharmacokinetic/pharmacodynamic (PK/PD) integration of enrofloxacin (ENR) and cefquinome (CEQ) alone and in combination. Results: Checkerboard assay results indicated that the combination treatment for type strain ATCC 700603 was synergistic effect with a fractional inhibitory concentration index (FICI) of ≤0.5. The other two clinical strains demonstrated an additive effect (FICI >0.5 to ≤1). Furthermore, static time-kill curves indicated that enrofloxacin and cefquinome added singly were effective in killing K. pneumoniae at concentrations of >2 MIC and ≥1 MIC, respectively. Additionally, the combination of enrofloxacin and cefquinome led to an enhanced antibacterial activity of cefquinome. The dynamic time-kill curves indicated that enrofloxacin and cefquinome had bactericidal and bacteriostatic activities, respectively at ≥1.5 mg/L (single-dose) and 4 mg/L (8 h split-dose) causing a decrease in bacterial counts of ≥4.45 and >2 log10 CFU/mL. Enrofloxacin possessed no bacteriostatic effects against K. pneumoniae at a constant concentration of 1× MIC. Cefquinome used in combination with 1× MIC enrofloxacin exhibited bactericidal activity at ≥4 mg/L (12 h split-dose) with reductions of ≥3.65 log10 CFU/mL. The PK/PD parameters were also analyzed to determine the concentration and duration of the drugs needed to reduce bacteria by 3 log10 CFU/mL. For enrofloxacin alone, the AUC24h/MIC was 23.29 h and the Cmax/MIC was 3.18. For cefquinome alone, the %T > MIC was 48.66 and when used in combination with enrofloxacin was 18.04. The combined use of cefquinome and enrofloxacin can increase the antibacterial activity of cefquinome against K. pneumoniae under a 12-h split-dose regimen regardless of individual drug susceptibility. Discussion: The static and dynamic time-kill curves indicated that enrofloxacin exhibited concentration-dependent activity, while cefquinome exhibited time-dependent activity. In the in vitro dynamic model, enrofloxacin alone exhibited better antimicrobial effects against K. pneumoniae compared to cefquinome alone. However, the antibacterial effect of cefquinome can be enhanced by combining it with enrofloxacin. These findings suggest a potentially effective approach for combating K. pneumoniae infections.

Monitoring the Prevalence of Antimicrobial Resistance in Companion Animals: Results from Clinical Isolates in an Italian University Veterinary Hospital

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 (p < 0.01 in both cases) and previous use of antimicrobials (p < 0.01 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.

Rapid identification of canine uropathogens by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry and the clinical factors that correlated bacterial species and antimicrobial resistance

Using the matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) method for bacterial diagnosis, rapid urine sample preparation can reduce time relapsing of diagnosis and improve discriminatory power in coinfection cases. We aimed to evaluate rapid urine preparation procedures before MALDI-TOF MS application using dog clinical urine samples in comparison with standard microbiological diagnostic methods by agreement analysis. We determined the frequency and distribution of bacteria and bacterial resistance and their correlations to clinical history. Three experimental procedures comprising direct centrifugation, 10% sodium dodecyl sulfate digestion, and ultrasonic preparation were performed for method validation and sensitivity. Sterile urine containing Escherichia coli and/or Staphylococcus aureus were used as simulated samples. By ultrasonic preparation, the microorganisms could be detected 1.46-1.51 × 105 CFU, which was considered the most suitable technique. This preparation was significantly consistent with the routine method based on data from Hospital Information Systems for 50 urine samples from canine cystitis. By standard protocol, Enterobacteriaceae and Staphylococcus pseudintermedius were found in most of the 155 urine samples with cystitis. Extended-spectrum beta-lactamase-producing Enterobacteriaceae was found in 25-30% of the samples. Imipenem resistance was found in 70% of Acinetobacter baumannii cases; almost all were resistant to second-generation fluoroquinolones and tetracyclines. The most efficient antibiotic for treating bacterial urinary tract infection was amoxicillin plus clavulanic acid. A. baumannii and Pseudomonas aeruginosa were susceptible to pradofloxacin. Prolonged urine catheterization was linked to lower urinary tract infections by Enterobacter spp., which also correlated with chronic kidney disease.

Assessing the urinary concentration of nitrofurantoin and its antibacterial activity against Escherichia coli, Staphylococcus pseudintermedius, and Enterococcus faecium isolated from dogs with urinary tract infections

Nitrofurantoin, a broad-spectrum nitrofuran class antibiotic, is applied as a first-line antibiotic in treating human urinary tract infections (UTIs) due to its great efficacy and high achievable concentration. The interest in using this antibiotic in companion animals has increased due to the growing demand for effective antibiotics to treat UTIs caused by multidrug-resistant bacteria. Currently, the susceptibility interpretations for nitrofurantoin are based on the breakpoints set for humans, while the canine-specific breakpoints are still unavailable. In this study, we assessed the concentration of nitrofurantoin reaching the dog's urine using the recommended oral dosing regimen. In addition, we examined the efficacy of this breakpoint concentration against the common canine UTI pathogens, Escherichia coli, Staphylococcus pseudintermedius, and Enterococcus faecium. Eight experimental beagle dogs were treated with ~5 mg/kg of nitrofurantoin macrocrystal PO 8qh for 7 days. The urine samples were collected via cystocentesis at 2, 4, and 6 h after administration on day 2 and day 7 and used to quantify nitrofurantoin concentrations by ultra-high performance liquid chromatography. The results showed that 26.13-315.87 μg/mL nitrofurantoin was detected in the dogs' urine with a mean and median concentration of 104.82 and 92.75 μg/mL, respectively. Additionally, individual dogs presented with urinary nitrofurantoin concentrations greater than 64 μg/mL for at least 50% of the dosing intervals. This concentration efficiently killed E. coli, and S. pseudintermedius, but not E. faecium strains carrying an MIC₉₀ value equal to 16, 16, and 128 μg/mL, respectively. Taken together, these results suggest that the value of 64 μg/mL may be set as a breakpoint against UTI pathogens, and nitrofurantoin could be an effective therapeutic drug against E. coli and S. pseudintermedius for canine UTIs.

Knowledge and Attitudes of Small Animal Veterinarians on Antimicrobial Use Practices Impacting the Selection of Antimicrobial Resistance in Dogs and Cats in Illinois, United States: A Spatial Epidemiological Approach

Inappropriate antimicrobial use in animals and humans has been associated with the emergence of antimicrobial resistance, which has become a global public health concern. Veterinarians’ practice locations and their knowledge and opinions on antimicrobial resistance may influence their antimicrobial prescription practices, which could impact the emergence of antimicrobial-resistant bacteria. This study used a spatial modeling approach to identify areas where veterinarians are knowledgeable about factors that impact the selection of antimicrobial resistance. In addition, we sought to identify regions with higher- and lower-than-expected response rates to our survey to aid future antimicrobial stewardship efforts. A total of 83 veterinarians who treated dogs and/or cats across 34 different Illinois counties responded to our online survey. Most of the responders (90.9%) considered that insufficient doses or duration of antibiotic treatments contribute the most to the selection of antimicrobial resistance. A high proportion of veterinarians (78.7%) attended educational programs on antimicrobial use and resistance; however, only 46.2% were knowledgeable about the current antimicrobial resistance profiles of prevalent bacteria in their area. A mean knowledge score for each county was calculated based on the responses of veterinarians to the survey questions. Local Moran’s I statistic was used to identify counties with high and low knowledge scores. A high knowledge score area in the northeast region and a low knowledge score area in the southeast of Illinois were identified. Using scan statistics with a Poisson model that accounted for the estimated number of veterinarians in a county, a higher-than-expected response rate area was identified in central-east Illinois and a lower-than-expected area in the northeast. This study showed the effectiveness of using geographic analysis and spatial statistics to identify locations where future antimicrobial stewardship programs should focus.