Antimicrobial resistance and genotyping of Pseudomonas aeruginosa isolated from the ear canals of dogs in Japan

Detection of Extended-Spectrum β-Lactamases, Metallo-β-Lactamases, Antimicrobial Resistance Profiles, and Biofilm-Forming Capacity in Pseudomonas aeruginosa Strains Recovered From Dogs With Otitis Externa in Italy

Pseudomonas aeruginosa is considered the second major causative agent of otitis externa in dogs, after Staphylococcus pseudintermedius. This study aimed to evaluate the antimicrobial resistance profiles and to detect the extended-spectrum β-lactamase (ESBL) and metallo-β-lactamase (MBL) genes in Pseudomonas aeruginosa (P. aeruginosa). Precisely, seventeen P. aeruginosa strains, recovered from auricular specimens of dogs affected by otitis externa, were identified by MALDI-TOF MS. Antimicrobial susceptibility testing was carried out against eleven clinically relevant antimicrobials using the Kirby Bauer disk diffusion method on Mueller Hinton agar plates. The PCR assay was performed to detect ESBL bla CTX-M ,  bla TEM ,  bla SHV ,  bla PER , and MBL bla IMP ,  bla OXA-48,  bla VIM ,  bla NDM ,  bla GES genes. The results showed that P. aeruginosa isolates had a phenotypic resistance value of 100% to ceftazidime, imipenem, and meropenem, followed by piperacillin-tazobactam, sulfamethoxazole-trimethoprim (94%), and aztreonam (88%). An alarming result was represented by the high prevalence of multidrug-resistant strains with 100% of the total isolates. The most common ESBL-genotype combination was bla PER  + bla SHV (29.4%). Thirteen isolates (76.5%) carried together bla VIM  + bla GES genes, which resulted to be the most common MBL-genotype combination. All the isolates harboring ESBL and MBL genes were biofilm producers, evaluated by the crystal violet-based assay and PCR. Precisely, 76.5% were strong biofilm producers, and 23.5% resulted in being moderate producers. No relationship was observed between strong or moderate biofilm producers and numerical variability of ESBL and MBL genes. This study revealed worrying antimicrobial resistance profiles of P. aeruginosa-associated canine otitis externa, considering also the zoonotic potential of this pathogen.

Genomic characterization of Pseudomonas aeruginosa from canine otitis highlights the need for a One Health approach to this opportunistic pathogen

In humans, Pseudomonas aeruginosa is well known as a prominent opportunistic pathogen associated with antimicrobial resistance (AMR), which presents a major challenge to successful treatment. This is also the case in animals, particularly in companion dogs where P. aeruginosa is a common cause of otitis. Despite its clinical significance, little data are available on the genomics and epidemiology of P. aeruginosa in dogs. To address this, we have genome-sequenced 34 canine otitis P. aeruginosa isolates from a veterinary referral hospital and analysed these along with a further 62 publicly available genomes from canine isolates. Phylogenetic analysis revealed that all three P. aeruginosa phylogroups, A-C, are represented amongst a diverse bacterial population isolated from dogs. We identify examples of persistent or recurrent infection by the same strain of up to 309 days between sampling, demonstrating the difficulty of successfully eradicating infection. Isolates encoded a variety of AMR genes with genomic and phenotypic AMR correlating poorly for β-lactams but showing complete concordance between fluoroquinolone resistance and quinolone resistance-determining regions (QRDRs) of DNA gyrase and topoisomerase IV. Pangenome-wide analysis between 80 canine otitis isolates (34 newly sequenced here and a further 46 publicly available) and a reference collection of 491 human isolates found no genes which were over-represented or specific to either host species, indicating similar strains infect both humans and dogs. This agrees with the sharing of multilocus sequence types between dogs and humans, including the isolation here of ST235 from three dogs, a lineage prominent among the multidrug resistant (MDR) and extensively drug-resistant (XDR) international high-risk clones of P. aeruginosa causing human infections. The presence of such 'high-risk' clones in companion dogs is concerning given their potential impact on animal health and the potential for zoonotic spread. These data provide new insight into this difficult-to-treat veterinary pathogen and promote the need for a One Health approach to tackling it.

Characterization of Canine Otitis Externa Pseudomonas aeruginosa Isolates and Their Sensitivities to Different Essential Oils

Otitis externa is common infection in dogs. Its most important aetiologic agent is Pseudomonas aeruginosa, which, besides its ability to form biofilm, can also be resistant to several antibiotics, leading to therapeutic failures in several cases. Promising therapeutic alternatives are constantly being sought to treat chronic, recurrent infections. Within the framework of this study, we investigated the antibacterial potential of essential oils against canine isolates of P. aeruginosa. Forty P. aeruginosa were isolated from individual dogs' otitis externa. They were identified by MALDI-TOF MS, their antibiotic susceptibility was determined with disk diffusion, and their genetic relatedness was established using pulsed-field gel electrophoresis. Fifty-seven essential oils were screened for their antipseudomonas effects using the drop plate method, and six essential oils-cinnamon (bark and leaf), bay, rosemary, thyme, and bitter orange-were further tested for their mature-biofilm-degrading capacities at 30 °C and 37 °C. Even though the molecular relatedness of the forty P. aeruginosa isolates could be excluded, all isolates' growth was inhibited and their biofilms degraded by a 2.5% concentration of cinnamon (bark and leaf), bay, rosemary, thyme, or bitter orange essential oil. Our results show that essential oils are potent alternatives in the treatment of otitis externa.

Global epidemiology of high priority and pandemic Pseudomonas aeruginosa in pets, livestock, wild, and aquatic animals: a systematic review and meta-analysis

High-priority and international high-risk Pseudomonas aeruginosa (PA) are emergent strains. Here, we performed the first systematic review and meta-analysis of studies that reported the frequency of PA, carbapenem (CARBR), and colistin (COLR) resistant PA in healthy and sick livestock (A), pets (B), wild (C), and aquatic animals (D) from January 2013 to January 2023, globally. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, 57 cross-sectional and eight prospective studies were found eligible. Random-effect models were used to determine the pooled prevalences. Phylogenetic analyses based on core-genome single nucleotide polymorphisms (SNPs) were performed using CSI Phylogeny 1.4. The overall pooled prevalence of PA, COLR-PA, and CARBR-PA were 18.6%, 4%, and 11.7%, respectively. Wild animals had the highest pooled prevalence of PA, 33.5%. The pooled prevalence of COLR was significantly higher in PA strains from sick than healthy animals (P < 0.0001). Furthermore, COLR was significantly highest in PA strains from wild animals, 9.8% [95% confidence interval (CI): 0.8-58.9], while CARBR was highest in PA strains from pets, 14.8% (95% CI: 6.7-29.8). Seven (ST235, ST111, ST233, ST244, ST357, ST308, and ST277) of the 10 high-risk CARBR-PA clones carrying ExoS/U were reported in animals. The SNP-based phylogenetic analysis of 23 genomes of CARBR-PA from animals obtained from publicly available databases revealed two closely related blaGES-carrying strains (<100 SNPs) in sick pets, suggesting a transmission event. A higher frequency of high-risk carbapenem than colistin-resistant PA strains exists in animals. These findings highlight the roles of different animal species, especially pets and wild animals in the persistence and dissemination of high-priority PA.

Outbreak of Carbapenem-Resistant High-Risk Clone ST244 of Pseudomonas aeruginosa in Dogs and Cats in Algeria

Background/Objectives: Pseudomonas aeruginosa causes chronic infections in humans and animals, especially cats and dogs. This bacterium's ability to adapt and acquire antibiotic resistance traits may complicate and exacerbate antibacterial therapy. This study aimed to evaluate the antibiotic resistance patterns, virulence factors and ability to form biofilms of P. aeruginosa strains isolated from Algerian dogs and cats. Methods: Nineteen samples were collected from healthy and diseased dogs and cats. Isolates were studied for their antibiotic-resistance patterns (disc diffusion method) and biofilm formation (Microtiter assay) and were whole-genome sequenced (MinION). Results: Nineteen P. aeruginosa strains (15 from dogs and 4 from cats) were isolated. Antibiotic-resistance phenotypes were observed against amoxicillin-clavulanic acid (100%); meanwhile, resistance towards ticarcillin was 40% (dogs) and 25% (cats), ticarcillin-clavulanic acid was 13.33% and 25% for dogs and cats, respectively, and imipenem was 75% (cats) and 20% (dogs). Moreover, 95% of strains were biofilm-producers. Different antimicrobial resistance genes (ARGs) were found: beta-lactamase genes, mainly PAO, OXA-494, OXA-50 and OXA-396 and an aminoglycoside gene (aph(3')-IIb). The main high-risk sequence types (STs) were ST244, 2788, 388 and 1247. A large panel of virulence genes was detected: exoS, exoT, exoY, lasA, toxA, prpL, algD, rhIA and others. Conclusions: The genetic variety in antibiotic-resistance genes of resistant and virulent P. aeruginosa strains in dogs makes public health protection difficult. Continuous monitoring and research in compliance with the One Health policy are needed to solve this problem.

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.

Prevalence and antibiotic resistance in bacterial isolates of dogs with ulcerative keratitis in São Paulo State, Brazil

OBJECTIVE

Identify microorganisms present in canine eyes affected by ulcerative keratitis and assess its resistance profile to available antimicrobial drugs.

METHODS

Samples were collected from 88 canine eyes that exhibited ulcerative keratitis. They were identified using MALDI-TOF and subjected to antimicrobial susceptibility testing by disk diffusion.

RESULTS

Among the assessed subjects, brachycephalic dogs accounted for 74.48% (50/83) of the evaluated canines. Among the 88 evaluated eyes, 90.9% (80/88) showed positive cultures, with 11.33% (10/88) of the samples isolating more than one species of bacteria. Of all bacterial isolates identified (90), Gram-positive bacteria accounted for 63.33% (57/90), while Gram-negative bacteria constituted 36.66% (33/90), with predominance of Staphylococcus spp. at 35.55% (32/90) being, Staphylococcus pseudintermedius at 68.75% (22/32), and Pseudomonas aeruginosa at 15.55% (14/90), respectively. Staphylococcus spp. exhibited resistance to penicillin (89.29%), sulfadiazine and trimethoprim (60.71%), and tetracycline (67.86%), while doxycycline (88.89%), cefotaxime (85.71%), chloramphenicol (82.14%), gentamicin, and moxifloxacin (78.57%) showed the highest sensitivity rates. Pseudomonas aeruginosa displayed sensitivity (100%) to gentamicin and imipenem, and resistance (8.33%) to norfloxacin, ciprofloxacin, and cefepime. Similarly, the Enterobacteriaceae family showed higher sensitivity to amikacin and gentamicin (88.89%), imipenem (88.24%), and levofloxacin (87.5%), with pronounced resistance to amoxicillin-clavulanate (50%) and cefazolin (47.06%). This highlights multiresistance in 23.33% (21/90) of the isolates.

CONCLUSIONS

The most isolated species in canine ulcerative keratitis are S. pseudintermedius and P. aeruginosa. However, other species were also isolated, demonstrating diversity in ocular microbiota infection. There is a high-rate multidrug resistance associated with canine ulcerative keratitis. Nevertheless, these strains exhibited sensitivity to antimicrobials commonly used in veterinary ophthalmology.

EAVLD 2024 - 7th Congress of the European Association of Veterinary Laboratory Diagnosticians

This abstract book contains the abstracts presented at the 7th Congress of the European Association of Veterinary Laboratory Diagnosticians.

Does Every Strain of Pseudomonas aeruginosa Attack the Same? Results of a Study of the Prevalence of Virulence Factors of Strains Obtained from Different Animal Species in Northeastern Poland

BACKGROUND

Pseudomonas aeruginosa is a pathogen that causes infections in animals and humans, with veterinary implications including ear infections in dogs, respiratory diseases in cats, and mastitis in ruminants. In humans, it causes severe hospital-acquired infections, particularly in immunosuppressed patients. This study aimed to identify and assess the prevalence of specific virulence factors in Pseudomonas aeruginosa isolates.

METHODS

We analyzed 98 Pseudomonas aeruginosa isolates from various animal samples (dogs, cats, ruminants, fowl) from northeastern Poland in 2019-2022 for virulence-related genes (toxA, exoU, exoT, exoS, lasB, plcN, plcH, pldA, aprA, gacA, algD, pelA, endA, and oprF) by PCR and assessed biofilm formation at 48 and 72 h. Genomic diversity was assessed by ERIC-PCR.

RESULTS

The obtained results showed that all strains harbored the pelA gene (100%), while the lowest prevalence was found for pldA (24%) and exoU (36%). Regardless of the animal species, strong biofilm forming ability was prevalent among the strains after both 48 h (75%) and 72 h (74%). We obtained as many as 87 different genotyping profiles, where the dominant one was profile ERIC-48, observed in four strains.

CONCLUSIONS

No correlation was found between presence or absence of determined genes and the nature of infection. Similarly, no correlation was found between biofilm-forming genes and biofilm strength. The high genetic diversity indicates challenges for effective prevention, emphasizing the need for ongoing monitoring and research.

Antimicrobial resistance of Pseudomonas aeruginosa: navigating clinical impacts, current resistance trends, and innovations in breaking therapies

Pseudomonas aeruginosa, a Gram-negative bacterium, is recognized for its adaptability and opportunistic nature. It poses a substantial challenge in clinical settings due to its complicated antibiotic resistance mechanisms, biofilm formation, and capacity for persistent infections in both animal and human hosts. Recent studies revealed a potential zoonotic transmission of P. aeruginosa between animals, the environment, and human populations which highlights awareness of this microbe. Implementation of the One Health approach, which underscores the connection between human, animal, and environmental health, we aim to offer a comprehensive perspective on the current landscape of P. aeruginosa management. This review presents innovative strategies designed to counteract P. aeruginosa infections. Traditional antibiotics, while effective in many cases, are increasingly compromised by the development of multidrug-resistant strains. Non-antibiotic avenues, such as quorum sensing inhibition, phage therapy, and nanoparticle-based treatments, are emerging as promising alternatives. However, their clinical application encounters obstacles like cost, side effects, and safety concerns. Effectively addressing P. aeruginosa infections necessitates persistent research efforts, advancements in clinical development, and a comprehension of host-pathogen interactions to deal with this resilient pathogen.

Pseudomonas spp. in Canine Otitis Externa

Canine otitis externa (OE) is a commonly diagnosed condition seen in veterinary practice worldwide. In this review, we discuss the mechanisms of the disease, with a particular focus on the biological characteristics of Pseudomonas aeruginosa and the impact that antibiotic resistance has on successful recovery from OE. We also consider potential alternatives to antimicrobial chemotherapy for the treatment of recalcitrant infections. P. aeruginosa is not a typical constituent of the canine ear microbiota, but is frequently isolated from cases of chronic OE, and the nature of this pathogen often makes treatment difficult. Biofilm formation is identified in 40-95% of P. aeruginosa from cases of OE and intrinsic and acquired antibiotic resistance, especially resistance to clinically important antibiotics, highlights the need for alternative treatments. The role of other virulence factors in OE remains relatively unexplored and further work is needed. The studies described in this work highlight several potential alternative treatments, including the use of bacteriophages. This review provides a summary of the aetiology of OE with particular reference to the dysbiosis that leads to colonisation by P. aeruginosa and highlights the need for novel treatments for the future management of P. aeruginosa otitis.