Characterization of ESBL- and AmpC-Producing and Fluoroquinolone-Resistant Enterobacteriaceae Isolated from Mouflons (Ovis orientalis musimon) in Austria and Germany

Clinical Characteristics and Prognosis of Hospital-Acquired Klebsiella pneumoniae Bacteremic Pneumonia versus Escherichia coli Bacteremic Pneumonia: A Retrospective Comparative Study

Objective

This research aimed to investigate the variations in clinical features and prognosis of HABP caused by E. coli and K. pneumoniae. We also aimed to evaluate the risk variables related to 30-day death in the investigated groups.

Methods

A single-center retrospective cohort research lasting four years was performed. A total of 117 patients with HABP were involved in this research. The primary prognosis was 30-day death.

Results

Among 117 patients with HABP, 60 patients were infected with K. pneumoniae (KP-HABP), and 57 patients were infected with E. coli (E. coli-HABP). A higher proportion of males, ICU admission, undergoing tracheotomy and trachea cannulation, carbapenem-resistant strains, inappropriate empirical therapy (IET), immune compromise, diabetes mellitus, and sepsis were observed in the patients with KP-HABP (all P < 0.05). Meanwhile, the median SOFA score and Pitt score were significantly (P < 0.001) higher in the KP-HABP group compared to the E. coli-HABP group. The 30-day death was 48.33% in the KP-HABP group and 24.56% in the E. coli-HABP group (P = 0.008). After adjusting for the main covariates, the hazard ratios for 30-day mortality in KP-HABP were 1.58 (95% CI:0.80-3.12), 3.24 (95% CI:1.48-7.06), 5.67 (95% CI:2.00-16.07), and 5.99 (95% CI:2.10-17.06), respectively. Multivariate logistic regression models revealed that IET, hypoproteinaemia, cerebral vascular disease (CVD), and SOFA score ≥ 5.0 were the independent risk variables for 30-day death in KP-HABP. Simultaneously, SOFA score ≥ 4.0 and Pitt score ≥ 2.0 were independent risk factors for 30-day mortality in E. coli-HABP.

Conclusion

The clinical features of HABP vary depending on whether it is caused by Escherichia coli or K. pneumoniae. KP-HABP patients have higher 30-day mortality than E. coli-HABP patients. To ensure greater validity, it is necessary to further verify this conclusion using a larger sample size.

A walk on the wild side: Wild ungulates as potential reservoirs of multi-drug resistant bacteria and genes, including Escherichia coli harbouring CTX-M beta-lactamases

Extended-spectrum β-lactamases (ESBL)-producing Enterobacterales have been classified as critical priority pathogens by the World Health Organization (WHO). ESBL are universally distributed and, in 2006, were firstly reported on a wild animal. Understanding the relative contributions of wild animals to ESBL circulation in the environment is urgently needed. In this work, we have conducted a nationwide study in Portugal to investigate the occurrence of bacteria carrying clinically significant antimicrobial resistance genes (ARG), using widely distributed wild ungulates as model species. A total of 151 antimicrobial resistant-Enterobacterales isolates were detected from 181 wild ungulates: 50% (44/88) of isolates from wild boar (Sus scrofa), 40.3% (25/62) from red deer (Cervus elaphus), 41.4% (12/29) from fallow deer (Dama dama) and 100% (2/2) from mouflon (Ovis aries subsp. musimon). Selected isolates showed a diversified resistance profile, with particularly high values corresponding to ampicillin (71.5%) and tetracycline (63.6%). Enterobacterales strains carried bla_TEM, tetA, tetB, sul2, sul1 or dfrA1 ARG genes. They also carried bla_CTX-M-type genes, which are prevalent in human infections, namely CTX-M-14, CTX-M-15 and CTX-M-98. Strikingly, this is the first report of CTX-M-98 in wildlife. Almost 40% (n = 59) of Enterobacterales were multi-drug resistant. The diversity of plasmids carried by ESBL isolates was remarkable, including IncF, K and P. This study highlights the potential role of wild ungulates as environmental reservoirs of CTX-M ESBL-producing E. coli and in the spill-over of AMR bacteria and their determinants. Our findings suggest that wild ungulates are useful as strategic sentinel species of AMR in terrestrial environments, especially in response to potential sources of anthropogenic pollution, providing early warning of potential risks to human, animal and environmental health.

Phenotypic and Genetic Characterization of Klebsiella pneumoniae Isolates from Wild Animals in Central Italy

Despite Klebsiella pneumoniae being widely recognized as a nosocomial pathogen, there is a critical lack in defining its reservoirs and sources of infections. Most studies on risk factors have focused on multidrug-resistant (MDR) isolates and clinically-oriented questions. Over a two-year period, we sampled 131 wild animals including mammal and bird species from three regions of Central Italy. All typical colonies isolated from the analytical portions were confirmed by real-time PCR and identified by MALDI-TOF mass spectrometry (MALDI-TOF MS). All confirmed K. pneumoniae isolates were tested for antimicrobial susceptibility to 29 antimicrobials and subjected to whole genome sequencing. Typical colonies were detected in 17 samples (13%), which were identified as K. pneumoniae (n = 16) and as K. quasipneumoniae (n = 1) by MALDI-TOF MS. The antimicrobial susceptibility profile showed that all the isolates were resistant to β-lactams (ceftobiprole, cloxacillin, cefazolin) and tetracycline; resistance to ertapenem and trimethoprim was observed and nine out of 16 K. pneumoniae isolates (56.2%) were classified as MDR. Genomic characterization allowed the detection of fluoroquinolone resistance-associated efflux pumps, fosfomycin and β-lactamase resistance genes, and virulence genes in the overall dataset. The cluster analysis of two isolates detected from wild boar with available clinical genomes showed the closest similarity. This study highlights the link between humans, domestic animals, and wildlife, showing that the current knowledge on this ecological context is lacking and that the potential health risks are underestimated.

Occurrence of Antimicrobial Resistance in the Environment in Germany, Austria, and Switzerland: A Narrative Review of Existing Evidence

(1) Background: This study summarizes the current research on antibiotic resistance (AR) in the environment conducted in Austria, Germany, and Switzerland; (2) Methods: A narrative systematic literature review of epidemiological studies based on searches in EMBASE and CAB abstracts (up to 16 June2021) was conducted. Environmental reservoirs included water sources, wastewater, animal husbandry, wildlife, soil, and sediment; (3) Results: Four hundred and four records were screened, and 52 studies were included. Thirteen studies examined aquatic environments, and eleven investigated wastewater. Eight studies investigated both wildlife and animal husbandry. Less evidence was available for sediments, soil, and air. Considerable heterogeneity in research focus, study design, sampling, and measurement of resistance was observed. Resistance to all categories of antimicrobials in the WHO CIA list was identified. Resistance to critically important and highly important substances was reported most frequently; (4) Conclusions: The current research scope presents data-gathering efforts. Usage of a unified protocol for isolate collection, selecting sampling sites, and susceptibility testing is required to provide results that can be compared between the studies and reservoirs. Epidemiological, environmental, and ecological factors should be considered in surveys of the environmental dissemination of AR. Systematic epidemiological studies investigating AR at the interface of human, animal, and environmental health are needed.

WGS-Based Phenotyping and Molecular Characterization of the Resistome, Virulome and Plasmid Replicons in Klebsiella pneumoniae Isolates from Powdered Milk Produced in Germany

The emergence of Klebsiella pneumoniae (K. pneumoniae) in German healthcare is worrying. It is not well-investigated in the veterinary world and food chains. In the current study, antibiotic susceptibility profiles of 24 K. pneumoniae strains isolated from powdered milk samples produced in Germany were investigated by a microdilution test. Next-generation sequencing (NGS) was applied to identify genomic determinants for antimicrobial resistance (AMR), virulence-associated genes and plasmids replicons. All isolates were susceptible to the majority (14/18) of tested antibiotics. Resistance to colistin, fosfomycin, chloramphenicol and piperacillin was found. The ambler class A ß-lactamase, blaSHV variants were identified in all isolates, of which blaSHV-187 was most prevalent and found in 50% of isolates. Single-nucleotide-variants of oqxA and oqxB conferring resistance to phenicol/quinolone were found in all isolates, and the oqxB17 was the most prevalent found in 46% of isolates. 67% of isolates harbored fosA genes; however, only one was fosfomycin-resistant. Two isolates harbored genes conferring resistance to colistin, despite being susceptible. The majority of identified virulome genes were iron uptake siderophores. Two enterobactins (entB, fepC), six adherence-related genes belonging to E. coli common pilus (ECP) and one secretion system (ompA gene) were found in all isolates. In contrast, yersiniabactin was found in two isolates. One ST23 strain was susceptible to all tested antibiotics, and harbored determinants discriminatory for hypervirulent strains, e.g., aerobactin, salmochelin, yersiniabactin, enterobactin and regulator of mucoid phenotype A genes that are highly associated with hypervirulent K. pneumoniae. The IncF plasmid family was found in all strains, while almost half of the isolates harbored Col440I-type plasmids and nine isolates harbored various Inc-type plasmids. The presence of K. pneumoniae carrying different resistomes and major virulent specific virulomes in powdered milk samples is alarming. This could threaten public health, particularly of neonates and infants consuming dried milk.

Presence of β-Lactamase-producing Enterobacterales and Salmonella Isolates in Marine Mammals

Marine mammals have been described as sentinels of the health of marine ecosystems. Therefore, the aim of this study was to investigate (i) the presence of extended-spectrum β-lactamase (ESBL)- and AmpC-producing Enterobacterales, which comprise several bacterial families important to the healthcare sector, as well as (ii) the presence of Salmonella in these coastal animals. The antimicrobial resistance pheno- and genotypes, as well as biocide susceptibility of Enterobacterales isolated from stranded marine mammals, were determined prior to their rehabilitation. All E. coli isolates (n = 27) were screened for virulence genes via DNA-based microarray, and twelve selected E. coli isolates were analyzed by whole-genome sequencing. Seventy-one percent of the Enterobacterales isolates exhibited a multidrug-resistant (MDR) pheno- and genotype. The gene bla_CMY (n = 51) was the predominant β-lactamase gene. In addition, bla_TEM-1 (n = 38), bla_SHV-33 (n = 8), bla_CTX-M-15 (n = 7), bla_OXA-1 (n = 7), bla_SHV-11 (n = 3), and bla_DHA-1 (n = 2) were detected. The most prevalent non-β-lactamase genes were sul2 (n = 38), strA (n = 34), strB (n = 34), and tet(A) (n = 34). Escherichia coli isolates belonging to the pandemic sequence types (STs) ST38, ST167, and ST648 were identified. Among Salmonella isolates (n = 18), S. Havana was the most prevalent serotype. The present study revealed a high prevalence of MDR bacteria and the presence of pandemic high-risk clones, both of which are indicators of anthropogenic antimicrobial pollution, in marine mammals.

The Animal-foods-environment interface of Klebsiella pneumoniae in Germany: an observational study on pathogenicity, resistance development and the current situation

Klebsiella (K.) pneumoniae as a multi-drug resistant (MDR) pathogen is an emerging challenge for clinicians worldwide. Virulence factors are capsular antigens, adherence factors, the O-lipopolysaccharide, and siderophores promoting infectivity. Mechanisms of antimicrobial resistance are inactivation of compounds via enzymes, change of membrane permeability, and alteration of the target site of the antimicrobial compound. In addition to environmental resistance, K. pneumoniae can survive increasing concentrations of disinfectants, if exposed. This review describes the temporal and spatial distribution of K. pneumoniae in the past decades in Germany, with emphases on the development of resistance in the non-human columns of the One-Health concept. In general, K. pneumoniae is a neglected pathogen in veterinary and environmental health, and the risk of human infection concerning animal contact and food consumption is barely investigated. Few reports exist (n = 26) on antibiotic resistance of isolates from non-human origin. Multi-drug resistance and extended-spectrum β-lactamase (MDR-ESBL) strains also resistant to carbapenems and antibiotics of the ß-lactam group harbor blaCTX-M, blaOXA, blaTEM, blaSHV, blaCMY, and PMQR have been found in animals, foods, and the environment. Colistin resistant strains carrying the mcr-1 gene were detected in wastewater. The blaCTX-M-15 and blaOXA-48 genes are the most frequently identified AMR genes in isolates of humans and were also the most predominant ESBL-genes in samples collected from animal hosts. Several aspects of the molecular epidemiology and resistance development of K. pneumoniae in farm animal populations, wildlife, and foods need intensive research. Environmental health has to be integrated into national research plans, as a lack of data is apparent. Increasing awareness of the fact that non-human sources can act as a reservoir for this pathogen has to be raised.

Detection of IncN-pST15 one-health plasmid harbouring blaKPC-2 in a hypermucoviscous Klebsiella pneumoniae CG258 isolated from an infected dog, Brazil

The emergence and rapid spread of carbapenemase‐producing Enterobacterales represents a serious public health concern. Critically, these global priority bacteria have begun to be reported in companion animals, implying a potential risk of cross‐transmission between humans and pets. Using long‐read (MinION) and short‐read (Illumina) sequencing technologies, we have identified and characterized a hypermucoviscous KPC‐2‐producing Klebsiella pneumoniae strain belonging to the high‐risk international clone ST11/CG258, in a dog with urinary tract infection. Strikingly, the bla_KPC‐2 gene was carried by a 54‐kb IncN plasmid assignated to ST15, which shared 99.8 and 96.8% pairwise identity with IncN‐pST15 plasmids from human and environmental K. pneumoniae strains, respectively; all come from an area with high endemicity of KPC‐2. Our findings suggest that IncN‐pST15 plasmids conferring carbapenem resistance can play as important a role as clonal transmission of K. pneumoniae, representing another major challenge for One Health.

Broad-Spectrum Cephalosporin-Resistant and/or Fluoroquinolone-Resistant Enterobacterales Associated with Canine and Feline Urogenital Infections

The aim of the present study was to characterize Enterobacterales resistant to 3rd and 4th generation cephalosporins, carbapenems and/or fluoroquinolones, isolated from dogs and cats with urogenital infections. In total, 36 strains (Escherichia coli (n = 28), Klebsiella pneumoniae (n = 3), Serratia marcescens, Raoultella ornithinolytica, Proteus mirabilis, Citrobacter portucalensis and Enterobacter cloacae (each n = 1)) were included in the present study, 28 from Austria and 8 from Serbia. Isolates were characterized by a polyphasic approach including susceptibility pheno- and genotyping and microarray-based assays. Escherichia (E.) coli isolates were additionally characterized by two-locus (fumC and fimH) sequence phylotyping and multi-locus sequence typing (MLST) of selected isolates. MLST of carbapenem-resistant Enterobacter cloacae isolates was also performed. Among E. coli, the most dominant phylogenetic group was B1 (27.8%), followed by C, (16.6%), A and Clade II (5.5% each), B2 and F (2.77% each). The most predominant β-lactam resistance genes were blaTEM (70%) and blaCTX-M (38.8%), blaCMY (25%). blaNDM was detected in one carbapenem-resistant Enterobacter cloacae ST114. The most common ST among selected E. coli was 744 (10.7% isolates). The pandemic clones ST131 and ST648 carrying CTX-M-15 were also detected. Remaining STs belonged to 469, 1287, 1463 and 1642. E. coli clonotyping revealed 20 CH types. Based on the presence of certain virulence genes, three isolates were categorized as ExPEC/UPEC. The most prevalent virulence factors were fimH detected in 61%, iucD and iss both in 55%, iroN in 27.8%, papC in 13.8% and sat in 8.3% isolates.

Infectious Wildlife Diseases in Austria-A Literature Review From 1980 Until 2017

This literature review examines infectious wildlife disease research in Austria. We analyzed 226 research papers, published between 1980 and 2017. We determined that wildlife disease papers increased significantly from 0.8 ± 0.8 publications per year in the first decade (1980–1989) when compared to 2008–2017 with an average of 12.9 ± 4.1 publications per year. We illustrate information about the most investigated diseases and highlight the lack of research into certain wildlife pathogens. A special emphasis was given to diseases with zoonotic potential. The review showed that research focused on a few select species like the red fox (Vulpes vulpes), red deer (Cervus elaphus), and wild boar (Sus scrofa), all game species. Moreover, diseases affecting livestock and human health were seen more often. The review also found that only a low number of publications actually stated disease prevalence and confidence interval data. The reported diseases identified were classified according to their notifiable status and the distribution at the wildlife–human and wildlife–livestock interface. Furthermore, we try to argue why research into some diseases is prioritized, and why other diseases are underrepresented in current Austrian research. While spatiotemporal indicators could not be assessed due to the variability in methodologies and objectives of various studies, the information provided by this review offers the first comprehensive evaluation of the status of infectious wildlife disease research in Austria. Therefore, this study could assist investigators to identify further areas of priorities for research and conservation efforts and for wildlife management professionals to inform policy and funding strategies. With this review, we want to encourage research in the field of wildlife diseases in Austria to enhance current knowledge in the prevention of further loss in biodiversity and to find new measures to promote “One Health” on a global scale.

Broad-Spectrum Cephalosporin-Resistant Klebsiella spp. Isolated from Diseased Horses in Austria

Simple Summary

Broad-spectrum cephalosporin-resistant Klebsiella pneumoniae is considered as a serious problem for public human health. To date, only a few broad-spectrum cephalosporin-resistant Klebsiella have been isolated from horses. Considering the zoonotic potential of the Klebsiella spp., and the close relationship between man and horse, this study intended to generate data on the genetic background of broad-spectrum cephalosporin-resistant Klebsiella spp. isolated from horses in Austria. Overall, samples isolated between 2012 and 2019 from 1541 horses underwent bacteriological testing, resulting in 51 specimens tested positive for Klebsiella ssp. Antimicrobial susceptibility tests revealed that seven Klebsiella ssp. isolates were not only cefotaxime-resistant but also showed resistance against other classes of antibiotics so that they were considered to be multidrug-resistant. Data from whole genome sequencing and mating experiments strongly suggest that the majority of antibiotic resistance genes is encoded on plasmids in these seven multidrug-resistant Klebsiella ssp. Considering the potential threat when commensal Klebsiella inhabiting a healthy human gut acquire new antibiotic resistances due to the exchange of plasmids with multidrug-resistant Klebsiella ssp. from horses, further monitoring of horses and other domestic animals for the presence of broad-spectrum cephalosporin-resistant Klebsiella, not only in Austria but worldwide is therefore advisable.

Abstract

The aim of the present study was to investigate the diversity of broad-spectrum cephalosporin-resistant Klebsiella spp. isolated from horses in Austria that originated from diseased horses. A total of seven non-repetitive cefotaxime-resistant Klebsiella sp. isolates were obtained during diagnostic activities from autumn 2012 to October 2019. Antimicrobial susceptibility testing was performed. The isolates were genotyped by whole-genome sequencing (WGS). Four out of seven Klebsiella isolates were identified as K. pneumoniae, two as K. michiganensis and one as K. oxytoca. All isolates displayed a multi-drug resistant phenotype. The detection of resistance genes reflected well the phenotypic resistance profiles of the respective isolates. All but one isolate displayed the extended-spectrum β-lactamases (ESBL) phenotype and carried CTX-M cefotaximases, whereas one isolate displayed an ESBL and AmpC phenotype and carried cephamycinase (CMY)-2 and sulfhydryl variable (SHV)-type b and Temoniera (TEM) β-lactamases. Among Klebsiella pneumoniae isolates, for different sequence types (ST) could be detected (ST147, ST307, ST1228, and a new ST4848). Besides resistance genes, a variety of virulence genes, including genes coding for yersiniabactin were detected. Considering the high proximity between horses and humans, our results undoubtedly identified a public health issue. This deserves to be also monitored in the years to come.

Simultaneous colonization by Escherichia coli and Klebsiella pneumoniae harboring mcr-1 in Brazil

CASE PRESENTATION

We present a case report of a woman, concurrently colonized by polymyxin-resistant E. coli and K. pneumoniae. A Brazilian female patient, in her mid-fifties, was hospitalized with schistosomiasis. During hospitalization, polymyxin-resistant E. coli and K. pneumoniae were isolated from surveillance cultures.

METHODS

Identification, antimicrobial susceptibility testings, PCR for mcr-1, plasmid transfer by conjugation and whole genome sequencing were performed.

RESULTS

E. coli ST744 and K. pneumoniae ST101 carrying mcr-1 gene were described. Transconjugant E. coli was positive for mcr-1 and IncX4 by PCR. The plasmid is a 33,304-base pair plasmid, and the mcr-1 gene was the only antimicrobial resistance gene present in the plasmid.

CONCLUSIONS

This study presents a case report of a hospitalized woman, concurrently colonized by mcr-1-harboring E. coli ST744, a different ST from previously described in Brazil, and a K. pneumoniae ST101.

The role of wildlife (wild birds) in the global transmission of antimicrobial resistance genes

Antimicrobial resistance is an urgent global health challenge in human and veterinary medicine. Wild animals are not directly exposed to clinically relevant antibiotics; however, antibacterial resistance in wild animals has been increasingly reported worldwide in parallel to the situation in human and veterinary medicine. This underlies the complexity of bacterial resistance in wild animals and the possible interspecies transmission between humans, domestic animals, the environment, and wildlife. This review summarizes the current data on expanded-spectrum β-lactamase (ESBL), AmpC β-lactamase, carbapenemase, and colistin resistance genes in Enterobacteriaceae isolates of wildlife origin. The aim of this review is to better understand the important role of wild animals as reservoirs and vectors in the global dissemination of crucial clinical antibacterial resistance. In this regard, continued surveillance is urgently needed worldwide.

Plasmid-mediated resistance is going wild

Multidrug resistant (MDR) Gram-negative bacteria have been increasingly reported in humans, companion animals and farm animals. The growing trend of plasmid-mediated resistance to antimicrobial classes of critical importance is attributed to the emergence of epidemic plasmids, rapidly disseminating resistance genes among the members of Enterobacteriaceae family. The use of antibiotics to treat humans and animals has had a significant impact on the environment and on wild animals living and feeding in human-influenced habitats. Wildlife can acquire MDR bacteria selected in hospitals, community or livestock from diverse sources, including wastewater, sewage systems, landfills, farm facilities or agriculture fields. Therefore, wild animals are considered indicators of environmental pollution by antibiotic resistant bacteria, but they can also act as reservoirs and vectors spreading antibiotic resistance across the globe. The level of resistance and reported plasmid-mediated resistance mechanisms observed in bacteria of wildlife origin seem to correlate well with the situation described in humans and domestic animals. Additionaly, the identification of epidemic plasmids in samples from different human, animal and wildlife sources underlines the role of horizontal gene transfer in the dissemination of resistance genes. The present review focuses on reports of plasmid-mediated resistance to critically important antimicrobial classes such as broad-spectrum beta-lactams and colistin in Enterobacteriaceae isolates from samples of wildlife origin. The role of plasmids in the dissemination of ESBL-, AmpC- and carbapenemase-encoding genes as well as plasmid-mediated colistin resistance determinants in wildlife are discussed, and their similarities to plasmids previously identified in samples of human clinical or livestock origin are highlighted. Furthermore, we present features of completely sequenced plasmids reported from wildlife Enterobacteriaceae isolates, with special focus on genes that could be associated with the plasticity and stable maintenance of these molecules in antibiotic-free environments.

Klebsiella pneumoniae: a major worldwide source and shuttle for antibiotic resistance

Klebsiella pneumoniae is an important multidrug-resistant (MDR) pathogen affecting humans and a major source for hospital infections associated with high morbidity and mortality due to limited treatment options. We summarize the wide resistome of this pathogen, which encompasses plentiful chromosomal and plasmid-encoded antibiotic resistance genes (ARGs). Under antibiotic selective pressure, K. pneumoniae continuously accumulates ARGs, by de novo mutations, and via acquisition of plasmids and transferable genetic elements, leading to extremely drug resistant (XDR) strains harboring a 'super resistome'. In the last two decades, numerous high-risk (HiR) MDR and XDR K. pneumoniae sequence types have emerged showing superior ability to cause multicontinent outbreaks, and continuous global dissemination. The data highlight the complex evolution of MDR and XDR K. pneumoniae, involving transfer and spread of ARGs, and epidemic plasmids in highly disseminating successful clones. With the worldwide catastrophe of antibiotic resistance and the urgent need to identify the main pathogens that pose a threat on the future of infectious diseases, further studies are warranted to determine the epidemic traits and plasmid acquisition in K. pneumoniae. There is a need for future genomic and translational studies to decipher specific targets in HiR clones to design targeted prevention and treatment.

Characterization of Four Multidrug Resistance Plasmids Captured from the Sediments of an Urban Coastal Wetland

Self-transmissible and mobilizable plasmids contribute to the emergence and spread of multidrug-resistant bacteria by enabling the horizontal transfer of acquired antibiotic resistance. The objective of this study was to capture and characterize self-transmissible and mobilizable resistance plasmids from a coastal wetland impacted by urban stormwater runoff and human wastewater during the rainy season. Four plasmids were captured, two self-transmissible and two mobilizable, using both mating and enrichment approaches. Plasmid genomes, sequenced with either Illumina or PacBio platforms, revealed representatives of incompatibility groups IncP-6, IncR, IncN3, and IncF. The plasmids ranged in size from 36 to 144 kb and encoded known resistance genes for most of the major classes of antibiotics used to treat Gram-negative infections (tetracyclines, sulfonamides, β-lactams, fluoroquinolones, aminoglycosides, and amphenicols). The mobilizable IncP-6 plasmid pLNU-11 was discovered in a strain of Citrobacter freundii enriched from the wetland sediments with tetracycline and nalidixic acid, and encodes a novel AmpC-like β-lactamase (bla_WDC-1), which shares less than 62% amino acid sequence identity with the PDC class of β-lactamases found in Pseudomonas aeruginosa. Although the IncR plasmid pTRE-1611 was captured by mating wetland bacteria with P. putida KT2440 as recipient, it was found to be mobilizable rather than self-transmissible. Two self-transmissible multidrug-resistance plasmids were also captured: the small (48 kb) IncN3 plasmid pTRE-131 was captured by mating wetland bacteria with Escherichia coli HY842 where it is seemed to be maintained at nearly 240 copies per cell, while the large (144 kb) IncF plasmid pTRE-2011, which was isolated from a cefotaxime-resistant environmental strain of E. coli ST744, exists at just a single copy per cell. Furthermore, pTRE-2011 bears the globally epidemic bla_CTX-M-55 extended-spectrum β-lactamase downstream of ISEcp1. Our results indicate that urban coastal wetlands are reservoirs of diverse self-transmissible and mobilizable plasmids of relevance to human health.

Highly Tigecycline-Resistant Klebsiella pneumoniae Sequence Type 11 (ST11) and ST147 Isolates from Companion Animals

In this study, we characterized two tigecycline-resistant Klebsiella pneumoniae isolates from dog urine samples. The isolates were genetically unrelated, belonging to sequence type 11 (ST11) and ST147, both classically related to human isolates. To the best of our knowledge, this is the first identification of tigecycline-resistant isolates from animals. We unveil here the worrisome circulation among animals of bacterial clones resistant to this last-resort antibiotic.

Plasmid-mediated quinolone resistance in Enterobacteriaceae: a systematic review with a focus on Mediterranean countries

Quinolones are a family of synthetic broad-spectrum antimicrobial drugs. These molecules have been widely prescribed to treat various infectious diseases and have been classified into several generations based on their spectrum of activity. Quinolones inhibit bacterial DNA synthesis by interfering with the action of DNA gyrase and topoisomerase IV. Mutations in the genes encoding these targets are the most common mechanisms of high-level fluoroquinolone resistance. Moreover, three mechanisms for plasmid-mediated quinolone resistance (PMQR) have been discovered since 1998 and include Qnr proteins, the aminoglycoside acetyltransferase AAC(6')-Ib-cr, and plasmid-mediated efflux pumps QepA and OqxAB. Plasmids with these mechanisms often encode additional antimicrobial resistance (extended spectrum beta-lactamases [ESBLs] and plasmidic AmpC [pAmpC] ß-lactamases) and can transfer multidrug resistance. The PMQR determinants are disseminated in Mediterranean countries with prevalence relatively high depending on the sources and the regions, highlighting the necessity of long-term surveillance for the future monitoring of trends in the occurrence of PMQR genes.