Genetic analyses ofPseudomonas aeruginosaisolated from healthy captive snakes: evidence of high inter- and intrasite dissemination and occurrence of antibiotic resistance genes

Prioritization of Critical Factors for Surveillance of the Dissemination of Antibiotic Resistance in Pseudomonas aeruginosa: A Systematic Review

Pseudomonas aeruginosa is the primary opportunistic human pathogen responsible for a range of acute and chronic infections; it poses a significant threat to immunocompromised patients and is the leading cause of morbidity and mortality for nosocomial infections. Its high resistance to a diverse array of antimicrobial agents presents an urgent health concern. Among the mechanisms contributing to resistance in P. aeruginosa, the horizontal acquisition of antibiotic resistance genes (ARGs) via mobile genetic elements (MGEs) has gained recognition as a substantial concern in clinical settings, thus indicating that a comprehensive understanding of ARG dissemination within the species is strongly required for surveillance. Here, two approaches, including a systematic literature analysis and a genome database survey, were employed to gain insights into ARG dissemination. The genome database enabled scrutinizing of all the available sequence information and various attributes of P. aeruginosa isolates, thus providing an extensive understanding of ARG dissemination within the species. By integrating both approaches, with a primary focus on the genome database survey, mobile ARGs that were linked or correlated with MGEs, important sequence types (STs) carrying diverse ARGs, and MGEs responsible for ARG dissemination were identified as critical factors requiring strict surveillance. Although human isolates play a primary role in dissemination, the importance of animal and environmental isolates has also been suggested. In this study, 25 critical mobile ARGs, 45 critical STs, and associated MGEs involved in ARG dissemination within the species, are suggested as critical factors. Surveillance and management of these prioritized factors across the One Health sectors are essential to mitigate the emergence of multidrug-resistant (MDR) and extensively resistant (XDR) P. aeruginosa in clinical settings.

Study of Zoonotic Pathogens in Alien Population of Veiled Chameleons (Chamaeleo calyptratus) in the Canary Islands (Spain)

Veiled chameleons (Chamaeleo calyptratus) are native to the Arabian Peninsula that have been introduced as pets in many regions around the world, such as the Canary Islands (Spain). In this work, the gastrointestinal content from veiled chameleons of Gran Canaria island (Canary Islands) has been analyzed to determine the presence of zoonotic bacteria. Forty animals were analyzed using different selective culture media and PCR. The most isolated bacteria were Yersinia enterocolitica (52.4%), followed by Salmonella spp. (40.0%), with positive isolates for Salmonella Tyhpi and Salmonella Typhimurium. Pseudomonas spp. was found in 32.5% of the chameleons. More than half were positive for Pseudomonas aeruginosa. Antibiotic-resistant Staphylococcus spp. was detected in six animals plus one isolate of non-resistant Staphylococcus hominis. Multiple mycobacteria species belonging to both tuberculous and non-tuberculous complexes were identified as well as Escherichia coli carrying the stx₁ and eae virulence genes with 12.5% and 7.5% prevalence, respectively. Listeria monocytogenes, Campylobacter spp., and Vibrio spp. were found in lower proportion (<5%). The results obtained indicate that veiled chameleons in Gran Canaria could be playing a role in the maintenance and dissemination of the pathogens detected, harming public health and biodiversity.

Zoonotic Bacteria in Anolis sp., an Invasive Species Introduced to the Canary Islands (Spain)

Lizards belonging to the genus Anolis are native to America and have been introduced in many parts of the world. In this work, a gastrointestinal microbiological analysis from Anolis sp. introduced to Tenerife, Canary Island, was carried out. A total of 74 individuals were analyzed by culture and molecular tools. Pseudomonas spp. was the most prevalent bacteria isolated (64.3%), followed by enteropathogenic Escherichia coli with at least one of the investigated virulent genes (stx1, stx2, and eae) (44.6%). The stx2 gene was more prevalent which differs to that reported in other reptiles, probably due to wastewater transmission. Campylobacter spp. was detected in 32.4% of the animals, highlighting the detection of C. jejuni and C. fetus by their relevance to public health. The zoonotic Staphylococcus lugdunensis, found in 14.9% of the animals, was firstly detected in reptiles. Vibrio sp. which is more associated with aquatic environments was found in 10.8% of the lizards in this study, with Vibrio cholerae being found in two of the animals. The prevalence of Salmonella sp. (5.4%) was low, compared with other studies carried out in reptiles. These results indicate that Anolis sp. in Tenerife could be playing a role in the maintenance and spread of the pathogens detected, being a possible risk factor for public health and biodiversity conservation.

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): antimicrobial-resistant Pseudomonas aeruginosa in dogs and cats

Pseudomonas aeruginosa (P. aeruginosa) was identified among the most relevant antimicrobial‐resistant (AMR) bacteria in the EU for dogs and cats in a previous scientific opinion. 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 P. aeruginosa can be considered eligible to be listed for Union intervention according to Article 5 of the AHL (33–90% 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%, 1–5%, 5–33% and 5–33% probability of meeting the criteria, respectively) and the AHAW Panel was uncertain whether it meets the criteria in Section 5 (Category E, 33–90% probability of meeting the criteria). The animal species to be listed for AMR P. aeruginosa according to Article 8 criteria are mainly dogs and cats.

The Bacterial Urban Resistome: Recent Advances

Cities that are densely populated are reservoirs of antibiotic resistant genes (ARGs). The overall presence of all resistance genes in a specific environment is defined as a resistome. Spatial proximity of surfaces and different hygienic conditions leads to the transfer of antibiotic resistant bacteria (ARB) within urban environments. Built environments, public transportation, green spaces, and citizens' behaviors all support persistence and transfer of antimicrobial resistances (AMR). Various unique aspects of urban settings that promote spread and resilience of ARGs/ARB are discussed: (i) the role of hospitals and recreational parks as reservoirs; (ii) private and public transportation as carriers of ARGs/ARB; (iii) the role of built environments as a hub for horizontal gene transfer even though they support lower microbial biodiversity than outdoor environments; (iv) the need to employ ecological and evolutionary concepts, such as modeling the fate of a specific ARG/ARB, to gain enhanced health risk assessments. Our understanding and our ability to control the rise of AMR in an urban setting is linked to our knowledge of the network connecting urban reservoirs and the environment.

Pseudomonas aeruginosa efflux pump superfamily (review of literature)

The significant increase in the number of antibiotic-resistant microorganisms observed in recent years is a public health problem worldwide. One of the molecular mechanisms for the formation of antimicrobial resistance in bacteria is the presence of efflux pumps. The review presents an analysis of experimental studies related to the study of efflux pumps in clinical strains of Pseudomonas aeruginosa, one of the representatives of hospital pathogens of the ESKAPE group. This review is intended for specialists developing new types of drugs against antibiotic-resistant strains, as well as researchers studying the mechanisms of bacterial resistance to antibiotics, heavy metals, biocides and other antimicrobial factors.

Antimicrobial resistance and virulence of Pseudomonas spp. among healthy animals: concern about exolysin ExlA detection

Pseudomonas is a ubiquitous genus that also causes human, animal and plant diseases. Most studies have focused on clinical P. aeruginosa strains from humans, but they are scarce on animal strains. This study was aimed to determine the occurrence of Pseudomonas spp. among faecal samples of healthy animals, and to analyse their antimicrobial resistance, and pathogenicity. Among 704 animal faecal samples analysed, 133 Pseudomonas spp. isolates (23 species) were recovered from 46 samples (6.5%), and classified in 75 different PFGE patterns. Low antimicrobial resistance levels were found, being the highest to aztreonam (50.3%). Five sequence-types (ST1648, ST1711, ST2096, ST2194, ST2252), two serotypes (O:3, O:6), and three virulotypes (analysing 15 virulence and quorum-sensing genes) were observed among the 9 P. aeruginosa strains. Type-3-Secretion System genes were absent in the six O:3-serotype strains that additionally showed high cytotoxicity and produced higher biofilm biomass, phenazine pigments and motility than PAO1 control strain. In these six strains, the exlAB locus, and other virulence genotypes (e.g. RGP69 pathogenicity island) exclusive of PA7 outliers were detected by whole genome sequencing. This is the first description of the presence of the ExlA exolysin in P. aeruginosa from healthy animals, highlighting their pathological importance.

The prevalence of Pseudomonas aeruginosa and multidrug resistant Pseudomonas aeruginosa in healthy captive ophidian

Background

Snakes are globally considered as pet animals, and millions of ophidians are bred in captivity. Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium that can act as an opportunistic pathogen of man and animals and is frequently present in the oral and cloacal microbiota of healthy ophidians. It can cause severe clinical diseases and often shows antibiotic resistance. The aim of this study was to evaluate the prevalence and antibiotic resistance profiles of P. aeruginosa isolated from the cloacal microbiota of a large population sample of healthy captive ophidians and to evaluate the statistical associations with farming conditions.

Methods

A total of 419 cloacal swabs were collected from snakes belonging to the Boidae (n = 45), Colubridae (n = 48) and Pythonidae (n = 326) families and inoculated onto complete culture media. Food, water and bedding samples were also analyzed. The antimicrobial susceptibility of P. aeruginosa isolates was evaluated through the Kirby-Bauer agar diffusion test. Statistical analyses were performed with the chi-square test.

Results

The prevalence of P. aeruginosa was 59.9%, and 35.5% of these strains were multidrug resistant (MDR). The prevalence of MDR P. aeruginosa was significantly higher in adult samples than in young samples, and widespread resistance to Cephalosporins, Polymyxins and Sulfonamides was observed. Statistically significant differences in the prevalence of P. aeruginosa were observed depending on the farm size and snake family. Feeding thawed prey was associated with a higher P. aeruginosa and MDR P. aeruginosa prevalence. Moreover, snakes fed home-raised prey had a significantly higher MDR P. aeruginosa prevalence than snakes fed commercially available feed. Less frequent terrarium cleaning was associated with a higher MDR P. aeruginosa prevalence. On the other hand, snake reproductive status was not significantly associated with P. aeruginosa or MDR P. aeruginosa prevalence. All food, water and bedding samples were negative for P. aeruginosa presence.

Discussion

The overall P. aeruginosa prevalence found in this study was lower than that found by other authors, but a high proportion of the isolates were MDR. This study highlighted the presence of constitutive (such as age and taxonomic family) and managerial (farm size, cleaning cycle frequency and food type) factors associated with P. aeruginosa and/or MDR P. aeruginosa prevalence. Good breeding management and proper antibiotic treatment of P. aeruginosa infections could help reduce the presence of P. aeruginosa and MDR P. aeruginosa in the gut microbiota of snakes and consequently reduce the risk to public health.

The occurrence of disinfectant and antibiotic-resistant genes in Escherichia coli isolated from chickens in Egypt

Aim:

This work aimed to determine the occurrence of antibiotic and disinfectant resistance genes in Escherichia coli isolated from chickens in Egypt.

Materials and Methods:

Organs (liver, lung, heart, yolk sac, and bone marrow) of 1500 chicken samples were collected from diseased chickens suffered from colibacillosis with PM findings as CRD, diarrhea and omphalitis from different governorates of Egypt as: Giza, EL-Bahira, Fayoum, El-Dakahlia, El-Ismalia, and El-Sharkia during 2015-2016. These samples were labeled and transported immediately on ice to the Reference laboratory for quality control on poultry production (RLQP). The samples were cultured onto MacConkey agar and Eosin Methylene Blue Agar. Isolation and identification of the E. coli were performed based on morphology, cultural, staining, and biochemical properties. Antimicrobial resistance test was carried out using disk diffusion method. The PCR employing tetA, qacED1 and qacA/B were carried out for detection of these genes in isolated E.coli.

Results:

The prevalence of E. coli in chicken was 34%. Predominant serotypes of E. coli which serologically identified were O128, O111, O44, O158, and O2. Antibiotic susceptibility test of E. coli revealed that 100% of isolates were resistant to ampicillin, erythromycin, and sulfamethoxazole-trimethoprim, while 73.53% and 38.23% of them were sensitive for colistin sulfate and levofloxacin, respectively. Antibiotic resistance genes as tetA gene were tested for isolated E. coli and detected by incidence rate of 91.18%. qac resistance genes resembling as qacED1 and qacA/B genes were detected in isolated E. coli 70.6% and 14.7%, respectively.

Conclusion:

E. coli isolated from chickens in Egypt was carried qac and antibiotic-resistant genes that affect the poultry industry.

Molecular identification and phylogenetic analysis of Bothrops insularis bacterial and fungal microbiota

Bothrops insularis, known as the golden lancehead snake, has its natural habitat restricted to Queimada Grande Island on the southern coast of Brazil. This culture-dependent study aimed to identify microorganisms obtained from the mouth, eyes, and cloaca of this species. Swabs from 20 snakes were collected for fungal and bacterial isolation. DNA was extracted from all samples, and identification was performed by amplifying the ITS1-5.8S-ITS2 regions and the 16S rDNA gene, respectively. All strains were identified and deposited in the GenBank nucleotide database. MEGA v6.0 software was utilized to construct phylogenetic trees. In total, 100 strains were isolated and characterized, from which 42 fungi were distributed into 23 species and 58 bacteria into 13 species. The genus Fusarium was predominant since 11 strains and probably a new species was isolated from this fungus. Pseudomonas aeruginosa and Enterococcus faecalis were the predominant groups of aerobic bacteria isolated. Phylogenetic analyses between bacterial and fungal sequences suggest a similarity between the microorganisms found on the island and on the continent. These findings may be attributed to anthropic actions resulting from both expeditions to the island and actions of migratory birds, which are the main sources of food for snakes.

High Prevalence of blaNDM-1, blaVIM, qacE, and qacEΔ1 Genes and Their Association with Decreased Susceptibility to Antibiotics and Common Hospital Biocides in Clinical Isolates of Acinetobacter baumannii

The objective of this study was to evaluate the susceptibility of metallo-β-lactamase (MBL)-producing Acinetobacter baumannii (A. baumannii) clinical isolates to biocides. We also determined the prevalence and correlation of efflux pump genes, class 1 integron and MBL encoding genes. In addition, bla_VIM, bla_NDM-1, qacE and qacEΔ1 nucleotide sequence analysis was performed and compared to sequences retrieved from GenBank at the National Center for Biotechnology Information database. A. baumannii had a resistance rate to carbapenem of 71.4% and 39.3% and was found to be a MBL producer. The minimum inhibitory concentrations (MICs) of chlorhexidine and cetrimide were higher than the recommended concentrations for disinfection in 54.5% and 77.3% of MBL-positive isolates respectively and their MICs were significantly higher among qac gene-positive isolates. Coexistence of qac genes was detected in 68.1% and 50% of the isolates with bla_VIM and bla_NDM-1 respectively. There was a significant correlation between the presence of qac genes and MBL-encoding bla_VIM and bla_NDM-1 genes. Each of the bla_NDM-1, bla_VIM, qacE and qacEΔ1 DNA sequences showed homology with each other and with similar sequences reported from other countries. The high incidence of Verona integron-encoded metallo-β-lactamases (VIM) and New-Delhi-metallo-β-lactamase (NDM) and qac genes in A.baumannii highlights emerging therapeutic challenges for being readily transferable between clinically relevant bacteria. In addition reduced susceptibility to chlorhexidine and cetrimide and the potential for cross resistance to some antibiotics necessitates the urgent need for healthcare facilities to periodically evaluate biocides efficacy, to address the issue of antiseptic resistance and to initiate a “biocidal stewardship”.

Strong incidence of Pseudomonas aeruginosa on bacterial rrs and ITS genetic structures of cystic fibrosis sputa

Cystic fibrosis (CF) lungs harbor a complex community of interacting microbes, including pathogens like Pseudomonas aeruginosa. Meta-taxogenomic analysis based on V5-V6 rrs PCR products of 52 P. aeruginosa-positive (Pp) and 52 P. aeruginosa-negative (Pn) pooled DNA extracts from CF sputa suggested positive associations between P. aeruginosa and Stenotrophomonas and Prevotella, but negative ones with Haemophilus, Neisseria and Burkholderia. Internal Transcribed Spacer analyses (RISA) from individual DNA extracts identified three significant genetic structures within the CF cohorts, and indicated an impact of P. aeruginosa. RISA clusters Ip and IIIp contained CF sputa with a P. aeruginosa prevalence above 93%, and of 24.2% in cluster IIp. Clusters Ip and IIIp showed lower RISA genetic diversity and richness than IIp. Highly similar cluster IIp RISA profiles were obtained from two patients harboring isolates of a same P. aeruginosa clone, suggesting convergent evolution in the structure of their microbiota. CF patients of cluster IIp had received significantly less antibiotics than patients of clusters Ip and IIIp but harbored the most resistant P. aeruginosa strains. Patients of cluster IIIp were older than those of Ip. The effects of P. aeruginosa on the RISA structures could not be fully dissociated from the above two confounding factors but several trends in these datasets support the conclusion of a strong incidence of P. aeruginosa on the genetic structure of CF lung microbiota.

The influence of the accessory genome on bacterial pathogen evolution

Bacterial pathogens exhibit significant variation in their genomic content of virulence factors. This reflects the abundance of strategies pathogens evolved to infect host organisms by suppressing host immunity. Molecular arms-races have been a strong driving force for the evolution of pathogenicity, with pathogens often encoding overlapping or redundant functions, such as type III protein secretion effectors and hosts encoding ever more sophisticated immune systems. The pathogens' frequent exposure to other microbes, either in their host or in the environment, provides opportunities for the acquisition or interchange of mobile genetic elements. These DNA elements accessorize the core genome and can play major roles in shaping genome structure and altering the complement of virulence factors. Here, we review the different mobile genetic elements focusing on the more recent discoveries and highlighting their role in shaping bacterial pathogen evolution.

The contribution of class 1 integron to antimicrobial resistance in Stenotrophomonas maltophilia

Two hundred clinical isolates of Stenotrophomonas maltophilia were examined for the presence of class 1 integron and for the susceptibility to 12 different antimicrobials and detergents. The prevalence of class 1 integron in S. maltophilia isolates was 11%. The class 1 integron-positive isolates exhibited a higher resistance to kanamycin, tobramycin, and trimethoprim-sulfamethoxazole (SXT) than the class 1 integron-negative ones. Polymerase chain reaction (PCR), amplifying the variable region of the class 1 integron, showed the existence of six different amplicon sizes, indicating that there are at least six different class 1 integrons distributed in the 23 class 1 integron-positive isolates. Sequence analysis of six representative PCR amplicons revealed that qacK, aac(6')-Ib', qacK-aac(6')-Ib, qacK-aac(6')-Ib-aac(6')-Ib, and qacL-aadB-cmlA-aadA2 were identified in the 550-, 800-, 1,200-, 1,800, and 3,600-bp amplicons, respectively. The sequence analysis of the 150-bp PCR amplicon demonstrated no additional resistance-associated genes except the basic genetic elements of class 1 integron. The impact of class 1 integron acquisition on the antimicrobials susceptibility was assayed by isogenic integron deletion mutant construction and the susceptibility test. The most significant contribution of the class 1 integron acquisition to S. maltophilia is the increased resistance to SXT.

Severe fibrinonecrotic enteritis caused by Pseudomonas aeruginosa in a captive monitor lizard (Varanus niloticus)

Pseudomonas aeruginosa is an important pathogen that has been implicated in a number of serious conditions in humans and animals. Studies regarding the efficacy of antimicrobial drugs against virulent strains of P. aeruginosa in human and animal hosts have demonstrated that common therapeutic options are sometimes ineffective. In captive animals, in particular reptiles, literature on this topic is scarce. In this study, a 6-yr-old monitor lizard, Varanus niloticus, died suddenly without previous symptoms. Postmortem examination and bacteriologic analysis of necropsy samples revealed severe fibrinonecrotic enteritis caused by P. aeruginosa. The isolate presented a typical resistance profile, showing resistance to amoxycillin-clavulanic acid, ampicillin, cephotaxime, and sulphamethoxazole-trimethoprim. Virulence characterization demonstrated that the bacterium was able to express hemolysins, DNases, gelatinases, and lipases and had biofilm-forming ability. This study highlights the importance of surveillance for antimicrobial resistance and virulence traits in captive animals, which may present a challenge to practitioners.

High level of resistance to aztreonam and ticarcillin in Pseudomonas aeruginosa isolated from soil of different crops in Brazil

Pseudomonas aeruginosa can be found in water, soil, plants and, human and animal fecal samples. It is an important nosocomial pathogenic agent characterized by an intrinsic resistance to multiple antimicrobial agents and the ability to develop high-level (acquired) multidrug resistance through some mechanisms, among them, by the acquisition of plasmids and integrons, which are mobile genetic elements. In this study, 40 isolates from Brazilian soil were analyzed for antibiotic resistance, presence of integrons and plasmidial profile. The results demonstrated that the vast majority of the isolates have shown resistance for aztreonam (92.5%, n=37) and ticarcillin (85%, n=34), four isolates presented plasmids and eight isolates possess the class 1 integron. These results demonstrated that environmental isolates of P. aeruginosa possess surprising antibiotic resistance profile to aztreonam and ticarcillin, two antimicrobial agents for clinical treatment of cystic fibrosis patients and other infections occurred by P. aeruginosa.

Diversity among strains of Pseudomonas aeruginosa from manure and soil, evaluated by multiple locus variable number tandem repeat analysis and antibiotic resistance profiles

The results of a multiple locus variable number of tandem repeat (VNTR) analysis (MLVA)-based study designed to understand the genetic diversity of soil and manure-borne Pseudomonas aeruginosa isolates, and the relationship between these isolates and a set of clinical and environmental isolates, are hereby reported. Fifteen described VNTR markers were first selected, and 62 isolates recovered from agricultural and industrial soils in France and Burkina Faso, and from cattle and horse manure, along with 26 snake-related isolates and 17 environmental and clinical isolates from international collections, were genotyped. Following a comparison with previously published 9-marker MLVA schemes, an optimal 13-marker MLVA scheme (MLVA13-Lyon) was identified that was found to be the most efficient, as it showed high typability (90%) and high discriminatory power (0.987). A comparison of MLVA with PFGE for typing of the snake-related isolates confirmed the MLVA13-Lyon scheme to be a robust method for quickly discriminating and inferring genetic relatedness among environmental isolates. The 62 isolates displayed wide diversity, since 41 MLVA types (i.e. MTs) were observed, with 26 MTs clustered in 10 MLVA clonal complexes (MCs). Three and eight MCs were found among soil and manure isolates, respectively. Only one MC contained both soil and manure-borne isolates. No common MC was observed between soil and manure-borne isolates and the snake-related or environmental and clinical isolates. Antibiotic resistance profiles were performed to determine a potential link between resistance properties and the selective pressure that might be present in the various habitats. Except for four soil and manure isolates resistant to ticarcillin and ticarcillin/clavulanic acid and one isolate from a hydrocarbon-contaminated soil resistant to imipenem, all environmental isolates showed wild-type antibiotic profiles.

Lagooning of wastewaters favors dissemination of clinically relevant Pseudomonas aeruginosa

The significance of wastewater treatment lagoons (WWTLs) as point sources of clinically relevant Pseudomonas aeruginosa that can disseminate through rural and peri-urban catchments was investigated. A panel of P. aeruginosa strains collected over three years from WWTLs and community-acquired infections was compared by pulsed field gel electrophoresis (PFGE) DNA fingerprinting and multilocus sequence typing (MLST). Forty-four distantly related PFGE profiles and four clonal complexes were found among the WWTL strains analyzed. Some genotypes were repeatedly detected from different parts of WWTLs, including the influent, suggesting an ability to migrate and persist over time. MLST showed all investigated lineages to match sequence types described in other countries and strains from major clinical clones such as PA14 of ST253 and "C" of ST17 were observed. Some of these genotypes matched isolates from community-acquired infections recorded in the WWTL geographic area. Most WWTL strains harbored the main P. aeruginosa virulence genes; 13% harbored exoU-encoded cytoxins, but on at least six different genomic islands, with some of these showing signs of genomic instability. P. aeruginosa appeared to be highly successful opportunistic colonizers of WWTLs. Lagooning of wastewaters was found to favor dissemination of clinically relevant P. aeruginosa among peri-urban watersheds.