Prevalence and Antimicrobial Resistance of Bacterial Uropathogens Isolated from Dogs and Cats

Short versus longer duration antibiotic treatment for urinary tract infections in companion animals: a systematic review and meta-analysis

BACKGROUND

Unnecessarily prolonged antibiotic durations may contribute to the development of resistance in both humans and animals. Veterinarians need evidence supporting antibiotic treatment durations. This systematic review and meta-analysis aimed to compare the efficacy of shorter durations of antibiotic treatment to longer durations in treating urinary tract infections (UTIs) in dogs and cats.

METHODS

Four databases (MEDLINE, Scopus, EMBASE, and CAB Abstracts) were searched from inception to October 2nd, 2024. Studies that reported the impact of antibiotic treatments of different durations for simple UTIs in dogs or cats and reported a primary outcome of interest, specifically clinical or microbiological resolution of the UTIs, were included. For each study, two reviewers independently screened extracted data and evaluated the risk of bias. Random effects models were used to compare pooled risk ratios of cure rates.

RESULTS

Of 2,324 studies screened, we identified three studies (two randomized and one nonrandomized controlled trial) which met our inclusion criteria for meta-analysis. Studies examined only 26 animals (9 events) across their short-duration arms and 28 animals (17 events) across long-duration arms. All studies were assessed as having high or serious risk of bias. The pooled risk ratio for cure with short versus longer durations of treatment was 0.55, 95% CI: 0.23-1.27; the evidence was graded as very low certainty. Studies compared 1 to 3-day durations, 3 days to 14-day and 3 days to 21-day durations.

CONCLUSION

Based on this data alone, we cannot make conclusions about the efficacy of short compared to long antibiotic durations for treating UTIs in cats and dogs; due to the low numbers of included studies and patients, the confidence intervals for the pooled risk ratio were wide and could be consistent with inferiority or superiority of shorter treatment. Existing evidence supports shorter durations of antibiotics for treating sporadic UTIs in dogs and cats, however this systematic review and meta-analysis highlights that this is still a serious knowledge gap that must be addressed. Studies that examine optimal antibiotic durations for treating UTIs in dogs and cats are urgently needed to support clinical decision-making, inform guidelines, and improve antimicrobial stewardship in veterinary medicine.

SYSTEMATIC REVIEW REGISTRATION

Open science framework ( https://doi.org/10.17605/OSF.IO/2YJPM ).

Multidrug-Resistant Uropathogens in Companion Animals: A Comprehensive Study from Clinical Cases and a Genomic Analysis of a CTX-M-14-Producing Escherichia coli ST354, a Leading Cause of Urinary Tract Infections

Urinary tract infections (UTIs) are common in small animals, posing significant clinical challenges due to their recurrence and discomfort. This study investigated the bacterial causes and antimicrobial resistance patterns of UTIs in dogs and cats presented to an important Veterinary Teaching Hospital in São Paulo, Brazil, the largest city in Latin America. Samples were collected from 31 dogs and 9 cats via ultrasound-guided cystocentesis. Bacterial cultures were performed, species identification was accomplished with matrix-assisted laser desorption ionization-time of flight mass spectrometry, and antimicrobial susceptibility testing was done using the Kirby-Bauer method. Escherichia coli was the most frequently isolated pathogen, accounting for 27.9% of cases, followed by Staphylococcus pseudintermedius, Proteus mirabilis, and Klebsiella pneumoniae. Ampicillin resistance was observed in 70.4% of enterobacteria, with many E. coli strains exhibiting multidrug resistance. Whole-genome sequencing of an extended-spectrum beta-lactamase-producing uropathogenic Escherichia coli strain from a feline patient was performed; it was identified as ST354, a leading cause of UTIs worldwide in humans and animals, carrying the blaCTX-M-14 gene and other resistance determinants. Phylogenetic analysis indicated genetic proximity between this strain and others from Brazilian poultry and environmental sources. These findings emphasize the need for antimicrobial resistance surveillance in veterinary UTIs and advocate for stricter antibiotic stewardship to inform diagnostic and therapeutic approaches within a One Health perspective.

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.

Surveillance of antimicrobial resistance in hospitalized companion animals in China in 2022-23

Objectives

In this study, bacteria isolated from companion animals in China were taxonomically identified and assessed for antimicrobial susceptibility to evaluate the prevalence of antimicrobial resistance (AMR) in pets.

Methods

From October 2022 to October 2023, 5468 samples were collected from pets, predominantly from cats and dogs, in China, of which 5253 bacterial strains were identified (>98%). Antimicrobial susceptibility was assessed using the VITEK 2 COMPACT system and the Kirby-Bauer disc diffusion method.

Results

The most common bacterial species were Escherichia coli (14.5%) and Staphylococcus pseudintermedius (13.6%). E. coli exhibited high resistance to ampicillin and cefpodoxime (56.8%-73.2%) but moderate resistance to doxycycline, trimethoprim-sulfamethoxazole, enrofloxacin, gentamicin, and amoxicillin-clavulanate (18.1%-38.5%). Klebsiella spp. and Enterobacter spp. were resistance to several antimicrobials (32.2%-57.7%). High susceptibility to imipenem was noted in Proteus spp., Pseudomonas spp., and Acinetobacter spp. (91.7%-94.1%). Coagulase-positive Staphylococcus spp. demonstrated higher resistance than coagulase-negative strains. Enterococcus faecium showed greater resistance to some antimicrobials compared with E. faecalis. Streptococcus spp. exhibited low resistance to enrofloxacin (1.6%) and penicillin (1.1%).

Conclusions

The study demonstrates that AMR is widespread in companion animals in China, emphasizing the need for continuous surveillance. The accumulation of commercial antimicrobial susceptibility data can improve understanding of AMR and promote more effective antimicrobial stewardship and clinical practices in veterinary medicine.

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.

The effect of consumption of cranberry (Vaccinium macrocarpon) on Escherichia coli adherence to feline uroepithelial cells in a blind randomised cross-over trial in cats

Introduction

Escherichia coli is the most common uropathogen in humans, dogs and cats. Dietary consumption of cranberry (Vaccinium macrocarpon) is known to be associated with a reduction in uropathogenic E. coli (UPEC) adhesion to human and canine urinary epithelial cell lines, but this has not been shown in cats.

Material and Methods

Six neutered domestic cats, one male and five females, were randomly fed three diets successively, one containing 0.1% cranberry powder, one containing 0.3% cranberry powder, and one being the control without cranberry. Naturally emitted urine was collected on the last two days of each period of two weeks and used for bacterial growth. Adherence to Crandell-Rees feline kidney (CRFK) uroepithelial cells of the feline UPEC C571 strain (positive for the papC gene marker for P-fimbriae and the fimA marker for type 1 pili and negative for the gene of the alpha haemolysin cytotoxin hlyA, and additionally non-haemolytic in vitro on blood agar) was quantified after growth in urine samples.

Results

Significant reductions in bacterial adherence to CRFK cells were observed for 60% of cats receiving 0.1% cranberry powder supplementation and for all cats receiving 0.3% cranberry powder supplementation, compared to the same animals consuming the control diet.

Conclusion

Dietary supplementation with cranberry may provide some degree of protection to cats against adhesion of UPEC to feline uroepithelial cells.

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.

Significance of scattered small echogenic foci floating in urinary bladder as ultrasonography finding in dogs

BACKGROUND

Despite the prevalence of echogenic foci floating in the urinary bladder seen in ultrasonography in dogs, surprisingly little has been written on its significance, including its potential association with urinalysis. The objective of the study was to determine the diagnostic value of the echogenic foci floating in urinary bladders in dogs.

RESULTS

- Cystosonography was performed on 45 dogs. Bladder contents were examined and divided into positive (containing echogenic particles) and negative (absent echogenic particles) groups according to the presence and absence of floating echogenic particles. Five mL of urine was collected via cystocentesis. Urine analysis and culture were done and the relationship between ultrasound evaluation and urinalysis results was investigated. In dogs with bladder echogenic particles in ultrasonography, the prevalence of hematuria, pyuria, bacteriuria, and lipiduria were 88.9%, 92.6%, 29.6%, and 70.3%, respectively. However, in dogs in which echogenic particles were not observed in their bladders, the prevalence of hematuria, pyuria, bacteriuria, and lipiduria was 77%, 50%, 5.5%, and 77%, respectively. There was a significant association between bladder debris and positive urine culture, with an odds ratio of 7.15 (95% confidence interval: 0.81-63.28) compared with matched controls. Furthermore, there was a significant relationship between the presence of floating echogenic particles with pyuria, and urine color ( p ≤ 0.05).

CONCLUSION

In conclusion, the present results showed the detection of bladder debris on ultrasound can be a predictor for pyuria and positive urine culture in dogs.

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.

Six-Year Prescription Pattern of Antimicrobial Use in Cats at the Veterinary Teaching Hospital of the University of Pisa

The use of antimicrobials has greatly contributed to improving animal health. However, their inappropriate use reduces their effectiveness in treating bacterial infections and contributes to the selection of resistance. This study aimed to retrospectively evaluate the six-year pattern (2017-2022) of antimicrobial use in cats visiting the Veterinary Teaching Hospital (VTH) of the University of Pisa (Italy). The total number of prescribed antimicrobials, the number of animals for which an antimicrobial was prescribed, and the total number of antimicrobial prescriptions showed a significant time trend decrease during the study period, except for the fixed-dose combinations. The most frequently prescribed antimicrobials were amoxicillin-clavulanic acid (Synulox) (39.1%) followed by enrofloxacin (29.8%). These antimicrobials were mostly prescribed to treat infections affecting the genitourinary tract (~30%), followed by the gastrointestinal tract, skin, and respiratory system affections. Antimicrobials in empirical associations represented 13.0% of the total antimicrobial prescriptions, and the combination of amoxicillin-clavulanic acid (Synulox) with enrofloxacin accounted for the majority. The oral route represented the main route of administration of prescribed antimicrobials, followed by parenteral and topical ones. Amoxicillin-clavulanic acid (Synulox) (37.2%), ceftriaxone (2.7%), and tobramycin (2.8%) were the most prescribed antimicrobials for the oral, parenteral, and topical routes, respectively. Antimicrobial prescriptions complied with prudent use recommendations in terms of availability of diagnosis, respect to the dose range, duration of treatment, and the use of medicinal products approved for the species. On the contrary, antimicrobial susceptibility tests were used infrequently (5.2%), lacking compliance with the existing guidelines observed in companion animal practice. Overall, additional interventions are required not only to improve the responsible use of antimicrobials in our feline practice but also to implement antimicrobial stewardship programs, enhancing diagnostics such as culture and sensitivity testing in the future.

Genotypic Characterization of Uropathogenic Escherichia coli from Companion Animals: Predominance of ST372 in Dogs and Human-Related ST73 in Cats

Extraintestinal pathogenic Escherichia coli (ExPEC) account for over 80% and 60% of bacterial urinary tract infections (UTIs) in humans and animals, respectively. As shared uropathogenic E. coli (UPEC) strains have been previously reported among humans and pets, our study aimed to characterize E. coli lineages among UTI isolates from dogs and cats and to assess their overlaps with human UPEC lineages. We analysed 315 non-duplicate E. coli isolates from the UT of dogs (198) and cats (117) collected in central Germany in 2019 and 2020 utilizing whole genome sequencing and in silico methods. Phylogroup B2 (77.8%), dog-associated sequence type (ST) 372 (18.1%), and human-associated ST73 (16.6%), were predominant. Other STs included ST12 (8.6%), ST141 (5.1%), ST127 (4.8%), and ST131 (3.5%). Among these, 58.4% were assigned to the ExPEC group and 51.1% to the UPEC group based on their virulence associated gene (VAG) profile (ExPEC, presence of ≥VAGs: papAH and/or papC, sfa/focG, afaD/draBC, kpsMTII, and iutA; UPEC, additionally cnf1 or hlyD). Extended-spectrum cephalosporin (ESC) resistance mediated by extended-spectrum β-lactamases (ESBL) and AmpC-β-lactamase was identified in 1.9% of the isolates, along with one carbapenemase-producing isolate and one isolate carrying a mcr gene. Low occurrence of ESC-resistant or multidrug-resistant (MDR) isolates (2.9%) in the two most frequently detected STs implies that E. coli isolated from UTIs of companion animals are to a lesser extent associated with resistance, but possess virulence-associated genes enabling efficient UT colonization and carriage. Detection of human-related pandemic lineages suggests interspecies transmission and underscores the importance of monitoring companion animals.

A new killing assay with the Caenorhabditis elegans PX627 mutant to assess the virulence of uropathogenic Escherichia coli strains

The nematode Caenorhabditis elegans (C. elegans) is a prime invertebrate host model for studying uropathogenic Escherichia coli (UPEC) pathogenesis. The aim of this work was to develop a new C. elegans killing assay based on feeding bacteria by the nematode throughout its life from the egg. With this model, the lifespan of C. elegans rrf-3, temperature-sterile, mutant, and PX627, auxin-inducible infertile, mutant fed UPEC strains, was compared. The behavior of three clinical UPEC strains and the non-pathogenic Escherichia coli OP50 strain was analyzed. Survival curves were generated by the Kaplan-Meier method and compared by the log-rank test over 10 days of follow-up. There was no significant difference between the survival curves obtained with each of the two C. elegans mutants (PX627 and rrf-3) fed with each of the strains of E. coli (OP50, G1722, G1473 or ER41). The UPEC strains were classified according to their virulence in vivo in the C. elegans PX627 mutant. The most virulent strain was ER41 which harbored the virulence genes fimA, papC and hlyA, expressed hemolysis in vitro and showed no antibiotic resistance. The least virulent strain was G1722 which only harbored the two adhesion factor genes, was not hemolytic and was resistant to multiple antibiotics. The C. elegans PX627 mutant fed with UPEC bacteria from the egg stage is a simple and inexpensive invertebrate animal model for assessing the in vivo virulence of different strains. The early exposure of C. elegans to pathogenic bacteria at the egg stage, without the need to change the incubation temperature, is an advantage over previously described C. elegans killing assays.

Does Nitrofurantoin Improve the Portfolio of Vets against Resistant Bacteria in Companion Animals?

In clinical practice in dogs and cats, antimicrobials are frequently used, sometimes overused or misused, increasing antimicrobial resistance (AMR). In order to limit the phenomenon, laws have been enacted and guidelines for prudent and rational use of antibiotics have been developed. Interestingly, old molecules such as nitrofurantoin could be used to achieve therapeutic success and overcome AMR. To better understand the suitability of this molecule in veterinary medicine, the authors performed a revision of the literature, searching on PubMed and entering the following keywords: nitrofurantoin, veterinary medicine, dog, and cat connected by the Boolean operator "and", without restrictions on the date of publication. Thirty papers were finally selected. It is possible to appreciate that papers dealing with nitrofurantoin have been written from the early 1960s to the middle of the 1970s, and then a long period passed without publications. Only at the beginning of the new century, nitrofurantoin was included or was sometimes the focus of papers dealing with its efficacy in veterinary medicine, mainly in the treatment of urinary tract infections. One recent paper dealt with pharmacokinetic features, and none was dedicated to pharmacokinetic/pharmacodynamic integration or modeling. Nitrofurantoin appears to be still effective against several pathogens that rarely develop resistance to this molecule.