Antimicrobial susceptibility survey on bacterial agents of canine and feline urinary tract infections: Weight of the empirical treatment

Antimicrobial susceptibility patterns of aerobic bacteria isolated from canine urinary samples in South East Queensland, 2013 to 2018

Urinary tract infections are a common diagnosis in dogs presenting to veterinary practice. Veterinarians often treat suspected infections empirically, either in the absence of culture and susceptibility testing results or whilst waiting for them. This study aimed to identify the bacteria most frequently isolated from canine urinary samples and their antimicrobial susceptibility patterns in South East Queensland (SEQ) to help guide responsible empirical antimicrobial prescription by the veterinary community in this geographical location. Cumulative antibiograms were generated from the results of 1284 culture-positive urinary samples in SEQ, obtained from a commercial veterinary laboratory over a 5-year period. Escherichia coli was the most commonly isolated bacterial species (43%), followed by Staphylococcus spp. (23%), Proteus spp. (21%) and Enterococcus spp. (10%). Of the six most common isolates, 97% had susceptibility to at least one low-importance antimicrobial. Susceptibility to the low-importance and first-line antimicrobial recommendation, amoxicillin, was 81% for E. coli and 24% for Staphylococcus spp. Susceptibility of both E. coli and Staphylococcus spp. to medium-importance and commonly recommended empirical antimicrobials, trimethoprim sulphonamides and amoxicillin-clavulanic acid was ≥85% and >92% for high-importance antimicrobials enrofloxacin and ceftiofur. Of the E. coli and Staphylococcus spp. isolates, 8.8% and 4%, respectively, were considered multidrug resistant. There was no increase in resistance to antimicrobials detected over the study period. Susceptibilities suggest low- and medium-importance antimicrobials remain acceptable first-line empirical treatments. However, this should be continually assessed and updated using local surveillance data.

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.

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.

Bacterial Isolates from Urinary Tract Infection in Dogs and Cats in Portugal, and Their Antibiotic Susceptibility Pattern: A Retrospective Study of 5 Years (2017-2021)

There are growing concerns regarding the rise of antimicrobial-resistant bacteria in companion animals. This study aimed to bring new insights into the current scenario of Portugal's antimicrobial resistance bacteria isolated from companion animals with urinary tract infections and is the first to be performed during a long period on a large scale. Of a total of 17472 urine samples analyzed, 12,166 (69.6%) (CI 12,200-12,200) were negative for bacterial growth, and 5306 (30.4%) (95% CI 5310-5310) had bacterial growth. Of the culture-positive samples, 5224 (96.6%) (95% CI 5220-5220) were pure cultures and 82 (3.2%) (95% CI 81.9-82.1) had mixed growth. Escherichia coli was the most frequently isolated bacteria (n=2360, 44.5%) (95% CI 2360-2360), followed by Proteus mirabilis (n=585, 11%) (95% CI 583-583), Enterococcus faecium (n=277, 5.2%) (95% CI 277-277) and Staphylococcus pseudintermedius (n=226, 4.3%) (95% CI 226-226). The overall susceptibility rates were low for erythromycin (45.3%) and clindamycin (51.3%), and high for aminoglycosides (96.3%), carbapenems (92.4%), trimethoprim-sulfamethoxazole (81.2%), and quinolones (79.9%). E. coli also showed considerable resistance to amoxicillin-clavulanic acid. The rates of multidrug-resistant bacteria are still high compared to the northern countries of Europe. This study's findings show the emergence of antibiotic resistance in the antibiotic agents commonly used in the treatment of UTIs in dogs and cats in Portugal.

A Retrospective Study of Antimicrobial Resistant Bacteria Associated with Feline and Canine Urinary Tract Infection in Hong Kong SAR, China—A Case Study on Implication of First-Line Antibiotics Use

Urinary tract infection (UTI) is a common clinical diagnosis for which empirical antibiotics are used in veterinary medicine. For veterinarians, the description of canine and feline antibiograms can help with making prudent use decisions and guideline formulation. For public health officers and epidemiologists, a urinary antibiogram overview helps track and trend antimicrobial resistance (AMR). There is currently a knowledge gap in AMR prevalence associated with urinary tract infection in feline and canine patients and the resistance percentage of these microbes against some of the over-the-counter antibiotics available to local pet owners. This study has two aims. First, it aims to investigate the frequency of the bacteria and bacterial-resistance pattern in urine samples obtained from feline and canine patients. Second, it aims to determine the resistance of Escherichia coli (E. coli), the most frequently isolated bacteria, to first-line antibiotics. Results: We identified the five most-frequently isolated bacterial species and determined these isolates’ antibiotic sensitivity and resistance. The most-frequently isolated bacteria in feline and canine patients was Escherichia coli (E. coli). E. coli was identified, on average, in 37.2% of canine and 46.5% of feline urine samples. Among feline urinary samples, Enterococcus (14.7%) and Staphylococcus (14.5%) spp. were isolated more frequently, followed by Pseudomonas (4.8%) and Klebsiella (5.2%) spp. (). In canine samples, Proteus (17.9%) and Staphylococcus (13.2%) spp. were isolated more frequently, followed by Enterococcus (10.0%) and Klebsiella (8.59%) spp. Among these isolates, 40 to 70% of Staphylococcus spp. bacterial isolates from feline and canine patients were resistant to amoxicillin and ampicillin. During the three-year study period, among canine patients, 10 to 20% of Staphylococcus spp. bacterial isolates were resistance to fluoroquinolones, other quinolones, and third-generation cephalosporins. Among feline patients, 10% of Staphylococcus spp., 15 to 20% of E. coli, 50 to 60% of Klebsiella spp., and 90% of Pseudomonas spp. were resistant to cefovecin, a commonly used antibiotic.

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): antimicrobial‐resistant Escherichia coli in dogs and cats, horses, swine, poultry, cattle, sheep and goats

Escherichia coli (E. coli) was identified among the most relevant antimicrobial‐resistant (AMR) bacteria in the EU for dogs and cats, horses, swine, poultry, cattle, sheep and goats in previous scientific opinions. Thus, it has been assessed according to the criteria of the Animal Health Law (AHL), in particular criteria of Article 7 on disease profile and impacts, Article 5 on its eligibility to be listed, Annex IV for its categorisation according to disease prevention and control rules as in Article 9 and Article 8 for listing animal species related to the bacterium. The assessment has been performed following a methodology previously published. The outcome is the median of the probability ranges provided by the experts, which indicates whether each criterion is fulfilled (lower bound ≥ 66%) or not (upper bound ≤ 33%), or whether there is uncertainty about fulfilment. Reasoning points are reported for criteria with uncertain outcome. According to the assessment here performed, it is uncertain whether AMR E. coli can be considered eligible to be listed for Union intervention according to Article 5 of the AHL (33–66% probability). According to the criteria in Annex IV, for the purpose of categorisation related to the level of prevention and control as in Article 9 of the AHL, the AHAW Panel concluded that the bacterium does not meet the criteria in Sections 1, 2, 3 and 4 (Categories A, B, C and D; 0–5%, 5–10%, 10–33% and 10–33% probability of meeting the criteria, respectively) and the AHAW Panel was uncertain whether it meets the criteria in Section 5 (Category E, 33–66% probability of meeting the criteria). The animal species to be listed for AMR E. coli according to Article 8 criteria include mammals, birds, reptiles and fish.

A review of the current concepts in canine urinary tract infections

Traditionally, urinary tract infections (UTIs) have been categorised as either uncomplicated or complicated in veterinary medicine, with treatment differing for the two categories. In human medicine, there is an additional category: Asymptomatic bacteriuria, which is the presence of bacteriuria without symptoms of infection. Escherichia coli (E.coli) is the most common bacterial species involved in UTIs in dogs. Clinical signs can be absent in dogs with complicated UTIs, and this has been likened to asymptomatic bacteriuria (ASB) in people and has been termed subclinical bacteriuria (SBU) with the treatment recommendations for SBU in dogs have been adapted from human recommendations. There is a shift in the current treatment of UTIs to help minimise the development of antimicrobial resistance. Routine screening of dogs with conditions that may predispose them to UTIs has been discouraged as has the treatment of SBU. This has been due to the increase in antimicrobial resistance (AMR).

Results of urinary bacterial cultures and antibiotic susceptibility testing of dogs and cats in the UK

Objectives

Bacterial urinary tract infections are a common diagnosis in small animal practice and antibiotics are often administered empirically. The aim of this study was to investigate the aetiology and antibiotic resistance of uropathogens in dogs and cats in the UK.

Materials and Methods

Retrospective study of uroculture and antibiotic susceptibility testing results (n=808) by disk diffusion processed at a veterinary pathology laboratory between 2011 and 2012.

Results

Significant bacteriuria was detected in 18.4% of samples from dogs and 10.0% from cats, most of which (>90%) yielded a single organism. Escherichia coli was the most prevalent bacterial species (54.7% and 55.6% of feline and canine isolates, respectively) followed by Proteus mirabilis in dog samples (22.7%) and Enterococcus spp. in cat samples (23.2%). Approximately a third of E. coli isolates were resistant to ampicillin but resistance was much lower among Enterococcus spp. and P. mirabilis. Resistance to amoxicillin‐clavulanic acid also seemed to be emerging, particularly in E. coli (almost 20% resistant). In contrast, resistance to trimethoprim‐sulfamethoxazole for uropathogens remained <13% except for P. mirabilis (19.4%). Overall, fluoroquinolones showed the best in vitro activity (resistance mostly below 10% for enrofloxacin and marbofloxacin).

Clinical Significance

Our results provide evidence of the emergence of resistance to antibiotics commonly used to treat bacterial urinary tract infections. Continued monitoring of the patterns of antibiotic resistance in uropathogens is needed to assess the adequacy of recommendations on the empiric therapy of these infections.

Evaluation of antimicrobial prescriptions in dogs with suspected bacterial urinary tract disease

Background

Antimicrobials are commonly used to treat urinary tract disease in dogs. Understanding antimicrobial use is a critical component of antimicrobial stewardship efforts.

Hypothesis/Objectives

To evaluate antimicrobial prescriptions for dogs diagnosed with acute cystitis, recurrent cystitis, and pyelonephritis.

Animals

Dogs prescribed antimicrobials for urinary tract disease at veterinary practices in the United States and Canada.

Materials and Methods

A retrospective review of antimicrobial prescriptions was performed.

Results

The main clinical concerns were sporadic bacterial cystitis (n = 6582), recurrent cystitis (n = 428), and pyelonephritis (n = 326). Amoxicillin/clavulanic acid (2702, 41%), cefpodoxime (1024, 16%), and amoxicillin (874, 13%) were most commonly prescribed for sporadic bacterial cystitis. The median prescribed duration was 12 days (range, 3‐60 days; interquartile range [IQR], 4 days). Shorter durations were used in 2018 (median, 10 days; IQR, 4 days) compared to both 2016 and 2017 (both median, 14 days; IQR, 4 days; P ≤ .0002).

Amoxicillin/clavulanic acid (146, 33%), marbofloxacin (95, 21%), and cefpodoxime (65, 14%) were most commonly used for recurrent cystitis; median duration of 14 days (range, 3‐77 days; IQR, 10.5 days). Amoxicillin/clavulanic acid (86, 26%), marbofloxacin (56, 17%), and enrofloxacin (36, 11%) were most commonly prescribed for pyelonephritis; however, 93 (29%) dogs received drug combinations. The median duration of treatment was 14 days (range, 3‐77 days; IQR, 11 days).

Conclusions and Clinical Importance

Decreases in duration and increased use of recommended first‐line antimicrobials were encouraging. Common drug choices and durations should still be targets for antimicrobial stewardship programs that aim to optimize antimicrobial use, concurrently maximizing patient benefits while minimizing antimicrobial use and use of higher tier antimicrobials.

Assessment of animal diseases caused by bacteria resistant to antimicrobials: Dogs and cats

In this opinion the antimicrobial-resistant bacteria responsible for transmissible diseases that constitute a threat to dog and cat health have been assessed. The assessment has been performed following a methodology based on information collected via an extensive literature review and expert judgement. Details of the methodology used for this assessment are explained in a separate opinion. A global state of play of antimicrobial resistant Staphylococcus pseudintermedius, Staphylococcus aureus, Staphylococcus schleiferi, Escherichia coli, Proteus mirabilis, Klebsiella spp., Enterobacter spp., Pseudomonas aeruginosa, Clostridium perfringens, Clostridioides difficile, Enterococcus faecalis and Enterococcus faecium has been provided. Among those bacteria, EFSA identified S. pseudintermedius, E. coli and P. aeruginosa with > 90% certainty as the most relevant antimicrobial resistant bacteria in the EU based on the available evidence. The animal health impact of these most relevant bacteria, as well as their eligibility for being listed and categorised within the animal health law framework will be assessed in separate scientific opinions.

On Gram-Positive- and Gram-Negative-Bacteria-Associated Canine and Feline Skin Infections: A 4-Year Retrospective Study of the University Veterinary Microbiology Diagnostic Laboratory of Naples, Italy

Simple Summary

Pet animals’ bacterial skin infections represent the main reason for presentation in small animal practice and are generally secondary complications of other pathological conditions. Pyoderma and otitis externa are generally caused by Staphylococcus spp., and particularly Staphylococcus pseudintermedius is often isolated from dogs and cats suffering from skin disorders. However, also Gram-negative bacteria, such as Pseudomonas aeruginosa and Escherichia coli, can be responsible for both otitis externa and pyoderma. Since multi-drug-resistant bacterial strains have become a relevant threat in veterinary medicine, this study aimed to identify the bacteria most frequently associated with the most common clinical cases of skin infections in dogs and cats attending the University Veterinary Teaching Hospital of Naples in the period from January 2016 to December 2019. Moreover, their antibiotic resistance profiles were evaluated, highlighting an increasing spread of multi-drug-resistant strains. It is worth noting that this spread may also concern humans because of their close contact with pets. Thus, it not only is of veterinary significance but also has zoonotic importance, with pets acting as reservoirs for humans, especially pet owners and veterinarians.

Abstract

A 4-year retrospective study (2016–2019) of selected routine bacteriological examinations of the veterinary microbiology laboratory of the University Veterinary Teaching Hospital of Naples (Italy) was carried out. A total of 189 bacteriological samples were collected from 171 dogs and 18 cats suffering from skin infections. In dogs, the most common cutaneous infection was otitis externa, while pyoderma was found to be prevalent in cats. The number of recorded Gram-positive strains over the study period did not vary considerably from year to year and was always significantly higher (p-value = 0.0007) in comparison with Gram-negative bacterial isolations. In dogs, Staphylococcus pseudintermedius was the most common identified Gram-positive bacterium (65%), while Pseudomonas aeruginosa (36%) was the one among the isolated Gram-negative bacteria. In cats, coagulase-negative staphylococci were the most predominant isolated bacteria (47%). The phenotypic profiles of antibiotic resistance showed that most of the strains were resistant to amoxicillin–clavulanate, penicillin, clindamycin, and trimethoprim–sulfamethoxazole. Several multi-drug-resistant strains (35%) were detected in canine isolates. An updating of antibiotic resistance profiles of the main Gram-positive and Gram-negative bacteria principally associated with skin infections of pet animals is necessary to improve stewardship programs of veterinary hospitals and clinics.

Antibiotic Stewardship for Canine and Feline Acute Urinary Tract Infection: An Observational Study in a Small Animal Hospital in Northwest Italy

Antimicrobial stewardship programs (ASPs) have been suggested to reduce antimicrobial resistance phenomena in veterinary medicine, as antibiotics are commonly used without microbiological confirmation. The aim of the present study is to design a specific working flow for a tailored antimicrobial treatment in the case of canine and feline urinary tract infections (UTIs). Urine samples were collected by cystocentesis from 16 dogs and 12 cats presenting acute signs of UTI. The therapy was decided according to the minimal inhibitory concentration, and it was possible to monitor 14 dogs and 11 cats. Rescue therapy (amoxicillin and clavulanic acid) was included in emergency cases. Escherichia coli, Proteus mirabilis, and Streptococcus canis were isolated in dogs, and Escherichia coli, Staphylococcus pseudintermedius, and Staphylococcus aureus were isolated in cats. No multidrug-resistant strains were detected, but all Staphylococci were methicillin resistant. Only one cat received rescue therapy, and only one dog was recruited. Dogs were treated with tetracycline (1/14), fluoroquinolones (6/14), beta-lactams (6/14), and gentamicin (1/14), while cats received fluoroquinolones (3/11), nitrofurans (1/11), clindamycin (1/11), and beta-lactams (6/11). The success rate was very high. Our findings are interesting because this is the first ASP in Italy, and it may be used as a model to develop ASPs for other pathologies.

Clinical and microbiological characterization of subclinical bacteriuria and sporadic bacterial cystitis in dogs with spontaneous hypercortisolism

Study's aims were to characterize subclinical bacteriuria (SB) and sporadic bacterial cystitis (SBC) in dogs with spontaneous hypercortisolism (HC). Prospective cross-sectional design divided patients as newly diagnosed (n = 27), poorly controlled (n  = 21), well controlled (n  = 34), and controls (n  = 19). Urine culture positive results were identified by MALDI-TOF and submitted to antibiogram. Escherichia coli was the most common microorganism (36%). The majority of positive cultures in HC were SB (12.2%). All 4.1% SBC cases were in well controlled HC cases. Bacteriuria correlated with low urine specific gravity and low lymphocyte count. HC degree of control correlated with leukocyturia. SB/SBC cases were treated based in antimicrobial susceptibility leading to microbiological cure in 75% of HC cases. Persistent infections occurred only in SB cases, all by E. coli which became more resistant. SB/SBC prevalence in canine HC is actually lower. Further evidence for current ISCAID guideline contraindication for SB treatment due to HC were provided.

[Bacterial urinary tract infection and subclinical bacteriuria in the dog: a current review]

Bacterial urinary tract infection (UTI) is a common clinical presentation in dogs and a frequent reason for the prescription of antimicrobial drugs. UTI refers to adherence, multiplication and persistence of an infectious agent within the urogenital system. This causes an associated inflammatory response as well as the pertaining clinical signs. Depending on the site of infection, UTI's may be classified as bacterial cystitis, prostatitis or pyelonephritis. In contrast, subclinical bacteriuria (SB) is defined as the presence of a significant number of bacteria in the urine of an individual not showing clinical signs referrable to UTI. UTI's typically occur as a consequence of ascending pathogen migration from the host's own fecal or distal urogenital microbial flora. The most commonly isolated pathogen in cases of UTI and SB is Escherichia coli. The diagnosis is based on clinical signs and the results of urine examination and culture. The recently revised guidelines of the International Society for Companion Animal Infectious Diseases provide detailed recommendations for diagnosis and management of different forms of bacterial UTI's in dogs. Adherence to treatment guidelines will improve treatment success and is imperative in avoiding further deterioration of the antimicrobial resistance situation.

Prevalence of bacteria and changes in trends in antimicrobial resistance of Escherichia coli isolated from positive canine urinary samples from an Australian referral hospital over a 5-year period (2013-2017)

Lower urinary tract disease is common in dogs with approximately 14% developing a bacterial lower urinary tract infection (UTI) during their lifetime. Empirical antimicrobials are often prescribed while waiting urine culture and susceptibility results. Regional knowledge of bacterial prevalence and antimicrobial resistance patterns aids veterinarians in antimicrobial choice. This study aimed to identify the prevalence of uropathogens in canine urine tract isolates and to assess for changes in antimicrobial resistance of Escherichia coli (E. coli) over a 5-year study period at a large multidisciplinary private referral hospital in Australia (January 2013-December 2017). The proportion of resistant isolates was compared across 5 years (Fisher's exact test and Cochran Armitage test for trend) for select antimicrobials towards E. coli. A total of 246 positive urine cultures were included. E. coli was the most prevalent uropathogen at 64%, followed by Proteus sp., Staphylococcus sp. and Enterococcus sp., respectively (9%, 8% and 7%). E. coli was most commonly resistant to amoxicillin at 41%. There was no statistically significant difference, nor trend, in resistance of E. coli isolates towards the selected antimicrobials over the 5 years. Resistance towards trimethoprim-sulfonamide was lower at 15%. This information will aid local veterinarians in selecting empirical antimicrobials pending culture results for the treatment of UTIs in dogs.

Urinary Tract Infection

"Urinary tract infection (UTI) is a common diagnosis in companion animal practice and is responsible for a significant proportion of antimicrobial use in veterinary medicine. The veterinary community has begun to follow the standards of care in human medicine and shift its definition of an UTI based on culture results and toward the presence of lower urinary tract symptoms. An improved understanding of the pathophysiology of UTI, risk factors for clinical disease, and the implementation of more reliable in-house diagnostic testing can lead to improved outcomes for patients and reduce inappropriate treatment. Investigation of antibiotic-sparing therapies holds some promise as well."