Antimicrobial Resistance and Type III Secretion System Virulotypes of Pseudomonas aeruginosa Isolates from Dogs and Cats in Primary Veterinary Hospitals in Japan: Identification of the International High-Risk Clone Sequence Type 235

Distribution of sequence types and antimicrobial resistance of clinical Pseudomonas aeruginosa isolates from dogs and cats visiting a veterinary teaching hospital in Thailand

BACKGROUND

Pseudomonas aeruginosa is an important opportunistic pathogen in dogs and cats and is resistant to several antimicrobial drugs; however, data on the clonal distribution of P. aeruginosa in veterinary hospital are limited. This study aimed to investigate the clonal dissemination and antimicrobial resistance of clinical P. aeruginosa in a veterinary teaching hospital in Thailand within a 1-year period. Minimum inhibitory concentration determination and whole genome sequencing were used for antimicrobial susceptibility analysis and genetic determination, respectively.

RESULTS

Forty-nine P. aeruginosa were isolated mostly from the skin, urinary tract, and ear canal of 39 dogs and 10 cats. These isolates belonged to 39 sequence types (STs) that included 9 strains of high-risk clones of ST235 (n = 2), ST244 (n = 2), ST274 (n = 2), ST277 (n = 1), ST308 (n = 1), and ST357 (n = 1). Overall antimicrobial resistance rate was low (< 25%), and no colistin-resistant strains were found. Two carbapenem-resistant strains belonging to ST235 and ST3405 were identified.

CONCLUSIONS

Clinical P. aeruginosa in dogs and cats represent STs diversity. High-risk clones and carbapenem-resistant strains are a public health concern. Nevertheless, this study was limited by a small number of isolates. Continuous monitoring is needed, particularly in large-scale settings with high numbers of P. aeruginosa, to restrict bacterial transfer from companion animal to humans in a veterinary hospital.

Rapid typing of Klebsiella pneumoniae and Pseudomonas aeruginosa by Fourier-transform Infrared spectroscopy informs infection control in veterinary settings

Introduction

The emergence of multi-drug resistant (MDR) pathogens linked to healthcare-associated infections (HCAIs) is an increasing concern in modern veterinary practice. Thus, rapid bacterial typing for real-time tracking of MDR hospital dissemination is still much needed to inform best infection control practices in a clinically relevant timeframe. To this end, the IR Biotyper using Fourier-Transform InfraRed (FTIR) spectroscopy has the potential to provide fast cluster analysis of potentially related organisms with substantial cost and turnaround time benefits.

Materials and methods

A collection of MDR bacterial isolates (n = 199, comprising 92 Klebsiella pneumoniae and 107 Pseudomonas aeruginosa) obtained from companion animal (i.e., dogs, cats and horses) clinical investigations, faecal and environmental screening from four veterinary facilities between 2012 and 2019 was analysed retrospectively by FTIR spectroscopy. Its performance was compared against MLST extracted from whole genomes of a subset of clustering isolates (proportionally to cluster size) for investigation of potential nosocomial transmission between patients and the surrounding hospital environments.

Results

Concordance between the FTIR and MLST types was overall high for K. pneumoniae (Adjusted Rand Index [ARI] of 0.958) and poor for P. aeruginosa (ARI of 0.313). FTIR K. pneumoniae clusters (n = 7) accurately segregated into their respective veterinary facility with evidence of intra-hospital spread of K. pneumoniae between patients and environmental surfaces. Notably, K. pneumoniae ST147 intensely circulated at one Small Animal Hospital ICU. Conversely, Pseudomonas aeruginosa FTIR clusters (n = 18) commonly contained isolates of diversified hospital source and heterogeneous genetic background (as also genetically related isolates spread across different clusters); nonetheless, dissemination of some clones, such as P. aeruginosa ST2644 in the equine hospital, was apparent. Importantly, FTIR clustering of clinical, colonisation and/or environmental isolates sharing genomically similar backgrounds was seen for both MDR organisms, highlighting likely cross-contamination events that led to clonal dissemination within settings.

Conclusion

FTIR spectroscopy has high discriminatory power for hospital epidemiological surveillance of veterinary K. pneumoniae and could provide sufficient information to support early detection of clonal dissemination, facilitating implementation of appropriate infection control measures. Further work and careful optimisation need to be carried out to improve its performance for typing of P. aeruginosa veterinary isolates.

Prevalence of the virulence genes and their correlation with carbapenem resistance amongst the Pseudomonas aeruginosa strains isolated from a tertiary hospital in China

Pseudomonas aeruginosa is one of the top-listed pathogens in nosocomial infection. It is notorious for its complicated virulence system and rapid adaptability to drugs or antimicrobials. In this study, we aimed to evaluate the prevalence of sixteen virulence genes in four groups including type III secretion system, biofilm formation, extracellular toxin biosynthesis and enzymes amongst 209 clinical Pseudomonas aeruginosa strains. We investigated the different distribution patterns of virulence genotypes based on carbapenem-resistant phenotype or the carriage of carbapenemase genes. The detection rate of each virulence gene varied greatly. phzM and plcN were detected in all collected strains, while pilB and exoU were only carried by a small portion of isolates (6.7% and 16.3%). Additionally, the number of genotypes observed in each group of examined virulence genes ranged from 4 to 8. Only the distribution of genotypes of type III secretion system showed statistical difference between carbapenem-mediated or carbapenem-resistant and carbapenem-sensitive strains. The virulence genotype of Pseudomonas aeruginosa was possibly interrelated to its resistance mechanism. Further research suggested that one particular TTSS genotype exhibited higher ratio in carbapenemase-producing strains and exoS was less frequently detected in CRPA strains carrying carbapenemase gene. Generally, the significant genetic diversity of virulence genes amongst Pseudomonas aeruginosa strains was highlighted in this study. Specific TTSS genotypes were associated with carbapenem-resistance. In particular, certain incompatibility might exist between exoS and carbapenemase genes, which provided valuable information for further understanding the relationship between carbapenem resistance and virulence.

Screening for Antimicrobial Resistance and Genes of Exotoxins in Pseudomonas aeruginosa Isolates from Infected Dogs and Cats in Poland

Pseudomonas aeruginosa has assumed an increasingly prominent role as the aetiological agent in serious hard-to-treat infections in animals and humans. In this study, 271 P. aeruginosa strains collected from dogs and cats were investigated. The aim of the research was to screen these P. aeruginosa strains for antibiotic resistance and the presence of selected virulence factor genes. Antibiotic resistance was determined using the Kirby-Bauer method, while virulence genes were detected by polymerase chain reaction (PCR). The most frequently detected resistance was to fluoroquinolones, ranging in prevalence from 17.3% for ciprofloxacin up to 83% for enrofloxacin. The resistance to carbapenems was 14% and 4.8% for imipenem and meropenem, respectively. Almost all P. aeruginosa strains harboured the exoT (97.8%) and lasB (93.4%) genes, while the lowest prevalence was found for exoU (17.3%) and plcH (17.3%). P. aeruginosa strains isolated from dogs that harboured the toxA gene were more frequently resistant to ceftazidime (p = 0.012), while the presence of the exoU gene was found to be connected with resistance to marbofloxacin (p = 0.025) and amikacin (p = 0.056). In strains originating from cats, only the connection between the presence of the exoU gene and resistance to enrofloxacin (p = 0.054) was observed. The confirmation of associations between virulence-factor-encoding genes and antibiotic resistance indicates that problems of antibiotic resistance may not only cause complications at the level of antibiotic dosage but also lead to changes in the virulence of the bacteria; thus, further studies in this area are required.

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

The strong bond between dogs and their owners creates a close association that could result in the transfer of antibiotic-resistant bacteria from canines to humans, potentially leading to the spread of antimicrobial resistance genes. Pseudomonas aeruginosa, a common causative agent of persistent ear infections in dogs, is often resistant to multiple antibiotics. Assessing the antimicrobial resistance profile and genotype of P. aeruginosa is crucial for the appropriate use of veterinary pharmaceuticals. However, in recent years, few studies have been conducted on this bacterium in Japan. We determined the antimicrobial resistance profile and genotype of P. aeruginosa isolated from the ear canal of dogs in Japan in 2020. Analysis of antimicrobial resistance using disk diffusion tests indicated a high frequency of resistance to most antimicrobial agents. Particularly, 29 isolates from the ear canals of the 29 affected dogs (100%) were resistant to cefovecin, cefpodoxime, and florfenicol; however, they were susceptible to cefepime and piperacillin/tazobactam. Only 3.4, 10.3, and 10.3% of the isolates were resistant to ceftazidime, tobramycin, and gentamicin, respectively. Furthermore, upon analyzing the population structure using multilocus sequence typing, a considerably large clonal complex was not observed in the tested isolates. Three isolates, namely ST3881, ST1646, and ST532, were clonally related to the clinically isolated sequence types in Japan (such as ST1831, ST1413, ST1812, and ST1849), which is indicative of dog-to-human transmission. Considering the variation in antibiotic resistance compared to that reported by previous studies and the potential risk of dog-to-human transmission, we believe that the survey for antimicrobial resistance profile and population structure should be continued regularly. However, the prevalence of multidrug-resistant P. aeruginosa in dogs in Japan is not a crisis.

Resistance genomics and molecular epidemiology of high-risk clones of ESBL-producing Pseudomonas aeruginosa in young children

Introduction

The emergence of multidrug-resistant Pseudomonas aeruginosa poses a global threat, but the distribution and resistance profiling are unclear, especially in young children. Infections due to P. aeruginosa are common, associated with high mortality, and increasingly β-lactam drug resistant.

Methods

We studied the molecular epidemiology and antibiotic resistance mechanisms in 294 clinicalisolates of P. aeruginosa from a pediatric hospital in China. Non-duplicate isolates were recovered from clinical cases and were identified using an API-20 kit followed by antimicrobial susceptibility testing using the VITEK®2 compact system (BioMerieux, France) and also by broth dilution method. In addition, a double-disc synergy test for the ESBL/E-test for MBL was performed. The presence of beta-lactamases, plasmid types, and sequence types was determined by PCR and sequencing.

Results

Fifty-six percent (n = 164) of the isolates were resistant to piperacillin-tazobactam, followed by cefepime (40%; n = 117), ceftazidime (39%; n = 115), imipenem (36%; n = 106), meropenem (33%; n = 97), and ciprofloxacin (32%; n = 94). Forty-two percent (n = 126) of the isolates were positive for ESBL according to the double-disc synergy test. The blaCTX-M-15 cephalosporinase was observed in 32% (n = 40/126), while 26% (n = 33/126) werepositive for blaNDM-1 carbapenemase. Aminoglycoside resistance gene aac(3)IIIawas observed in 16% (n = 20/126), and glycylcyclines resistance gene tet(A) was observed in 12% (n = 15/126) of the isolates. A total of 23 sequence types were detected, including ST1963 (12%; n = 16), followed by ST381 (11%; n = 14), ST234 (10%; n = 13), ST145 (58%; n = 10), ST304 (57%; n = 9), ST663 (5%; n = 7), and a novel strain. In ESBL-producing P. aeruginosa, 12 different Incompatibility groups (Inc) were observed, the most common being IncFI, IncFIS, and IncA/C. The MOBP was the most common plasmid type, followed by MOBH, MOBF, and MOBQ.

Discussion

Our data suggest that the spread of antibiotic resistance is likely due toclonal spread and dissemination of different clinical strains of P. aeruginosa harbouring different plasmids. This is a growing threat in hospitals particularly in young children which needs robust prevention strategies.

Mechanisms of Antibiotic and Biocide Resistance That Contribute to Pseudomonas aeruginosa Persistence in the Hospital Environment

Pseudomonas aeruginosa is an opportunistic bacterial pathogen responsible for multiple hospital- and community-acquired infections, both in human and veterinary medicine. P. aeruginosa persistence in clinical settings is worrisome and is a result of its remarkable flexibility and adaptability. This species exhibits several characteristics that allow it to thrive under different environmental conditions, including the ability to colonize inert materials such as medical equipment and hospital surfaces. P. aeruginosa presents several intrinsic mechanisms of defense that allow it to survive external aggressions, but it is also able to develop strategies and evolve into multiple phenotypes to persevere, which include antimicrobial-tolerant strains, persister cells, and biofilms. Currently, these emergent pathogenic strains are a worldwide problem and a major concern. Biocides are frequently used as a complementary/combination strategy to control the dissemination of P. aeruginosa-resistant strains; however, tolerance to commonly used biocides has also already been reported, representing an impediment to the effective elimination of this important pathogen from clinical settings. This review focuses on the characteristics of P. aeruginosa responsible for its persistence in hospital environments, including those associated with its antibiotic and biocide resistance ability.

Antimicrobial Resistance and Genetic Diversity of Pseudomonas aeruginosa Strains Isolated from Equine and Other Veterinary Samples

Pseudomonas aeruginosa is one of the leading causes of healthcare-associated infections in humans. This bacterium is less represented in veterinary medicine, despite causing difficult-to-treat infections due to its capacity to acquire antimicrobial resistance, produce biofilms, and persist in the environment, along with its limited number of veterinary antibiotic therapies. Here, we explored susceptibility profiles to antibiotics and to didecyldimethylammonium chloride (DDAC), a quaternary ammonium widely used as a disinfectant, in 168 P. aeruginosa strains isolated from animals, mainly Equidae. A genomic study was performed on 41 of these strains to determine their serotype, sequence type (ST), relatedness, and resistome. Overall, 7.7% of animal strains were resistant to carbapenems, 10.1% presented a multidrug-resistant (MDR) profile, and 11.3% showed decreased susceptibility (DS) to DDAC. Genomic analyses revealed that the study population was diverse, and 4.9% were ST235, which is considered the most relevant human high-risk clone worldwide. This study found P. aeruginosa populations with carbapenem resistance, multidrug resistance, and DS to DDAC in equine and canine isolates. These strains, which are not susceptible to antibiotics used in veterinary and human medicine, warrant close the setting up of a clone monitoring, based on that already in place in human medicine, in a one-health approach.

The Intriguing Carbapenemases of Pseudomonas aeruginosa: Current Status, Genetic Profile, and Global Epidemiology

Worldwide, Pseudomonas aeruginosa remains a leading nosocomial pathogen that is difficult to treat and constitutes a challenging menace to healthcare systems. P. aeruginosa shows increased and alarming resistance to carbapenems, long acknowledged as last-resort antibiotics for treatment of resistant infections. Varied and recalcitrant pathways of resistance to carbapenems can simultaneously occur in P. aeruginosa, including the production of carbapenemases, broadest spectrum types of β-lactamases that hydrolyze virtually almost all β-lactams, including carbapenems. The organism can produce chromosomal, plasmid-encoded, and integron- or transposon-mediated carbapenemases from different molecular classes. These include Ambler class A (KPC and some types of GES enzymes), class B (different metallo-β-lactamases such as IMP, VIM, and NDM), and class D (oxacillinases with carbapenem-hydrolyzing capacity like OXA-198) enzymes. Additionally, derepression of chromosomal AmpC cephalosporinases in P. aeruginosa contributes to carbapenem resistance in the presence of other concomitant mechanisms such as impermeability or efflux overexpression. Epidemiologic and molecular evidence of carbapenemases in P. aeruginosa has been long accumulating, and reports of their existence in different geographical areas of the world currently exist. Such reports are continuously being updated and reveal emerging varieties of carbapenemases and/or new genetic environments. This review summarizes carbapenemases of importance in P. aeruginosa, highlights their genetic profile, and presents current knowledge about their global epidemiology.

Genomic landscape of blaGES-5- and blaGES-24-harboring Gram-negative bacteria from hospital wastewater: emergence of class 3 integron-associated blaGES-24 genes

OBJECTIVES

This study aimed to characterize Gram negative bacteria carrying bla_GES carbapenemase genes detected in wastewater from a hospital with no history of detection of clinical isolates producing GES carbapenemases.

METHODS

Six hospital effluent samples were screened for carbapenemase-producing organisms (CPO) using CHROMagar mSuperCARBA and MacConkey agar with 1 µg/mL imipenem. Polymerase chain reaction (PCR) amplification and sequencing of carbapenemase genes, multilocus sequence typing, antimicrobial susceptibility testing, and whole-genome sequencing were performed.

RESULTS

Among 21 CPO isolates, 11 Klebsiella spp. and 5 Enterobacter kobei isolates carried bla_GES-24, and 4 E. roggenkampii and 1 Pseudomonas aeruginosa isolates carried bla_GES-5. Genomic analysis of 8 representative isolates comprising 6 bla_GES-24-positive and 2 bla_GES-5-positive revealed that class 3 integrons with complete or defective Tn402-like transposition modules were predominantly associated with two tandem copies of bla_GES-24. Furthermore, a total of 5 new class 3 integrons, In3-18 to In3-22, were identified among 5 bla_GES-24 and 1 bla_GES-5 plasmids. One strain each of K. pneumoniae subsp. pneumoniae and K. quasipneumoniae subsp. similipneumoniae harboring bla_GES-24 plasmids also carried a rare bla_VEB-1-positive class 1 integron on a non-typeable plasmid, where these bla_VEB-1 plasmids had high sequence similarity. Virulence gene profiles differed between Klebsiella spp. and Enterobacter spp.; the former harbored type III fimbriae cluster, salmochelin, and T6SS type i2 gene clusters, while the latter had curli pili operon, aerobactin, T2SS gene clusters, and T6SS type i3 gene clusters.

CONCLUSION

Our findings confirmed the linkage of bla_GES-24 with rare Tn402-like class 3 integrons and the structural diversity of their gene cassette arrays.