Pseudomonas aeruginosa population structure revisited under environmental focus: impact of water quality and phage pressure

Abstract

Pseudomonas aeruginosa attracts research attention as a common opportunistic nosocomial pathogen causing severe health problems in humans. Nevertheless, its primary habitat is the natural environment. Here, we relate the genetic diversity of 381 environmental isolates from rivers in northern Germany to ecological factors such as river system, season of sampling and different levels of water quality. From representatives of 99 environmental clones, also in comparison with 91 clinical isolates, we determined motility phenotypes, virulence factors, biofilm formation, serotype and the resistance to seven environmental P.aeruginosa phages. The integration of genetic, ecological and phenotypic data showed (i) the presence of several extended clonal complexes (ecc) which are non-uniformly distributed across different water qualities, and (ii) a correlation of the hosts' serotype composition with susceptibility towards distinct groups of environmental phages. For at least one ecc (eccB), we assumed the ecophysiological differences on environmental water adaptation and phage resistance to be so distinct as to reinforce an environmentally driven cladogenic split from the remainder of P.aeruginosa. In summary, we conclude that the majority of the microevolutionary population dynamics of P.aeruginosa were shaped by the natural environment and not by the clinical habitat.

Characterisation of Pseudomonas aeruginosa related to bovine mastitis

“…As the maximum antibiotic concentration in this study was 512 μg/mL, the same value was used in calculations with MIC or MBEC values higher than 512 μg/mL, and these values have been presented with the inequality sign. CIP, Ciprofloxacin; MEP, Meropenem; GEN, Gentamicin; AMK, Amikacin; COL, Colistin; KAN, Kanamycin; TET, Tetracycline; ERY, Erythromycin; CHL, Chloramphenicol; PIP, Piperacillin; AZT, Aztreonam; CFT, Cefoxitin A total of 99.2% of P. aeruginosa isolates in Korea have at least 1 of 4 TTSS-related genes, which is in harmony with earlier findings for human, environmental and bovine isolates of P. aeruginosa (Wiehlmann et al, 2007;Selezska et al, 2012;Szmolka et al, 2012). Of the 122 P. aeruginosa isolates, 68.8% of isolates were non-cytotoxic/invasive strain (exoU-/exoS+), while only 8.2% of isolates were cytotoxic/non-invasive strain (exoU+/exoS-).…”

“…Of the 122 P. aeruginosa isolates, 68.8% of isolates were non-cytotoxic/invasive strain (exoU-/exoS+), while only 8.2% of isolates were cytotoxic/non-invasive strain (exoU+/exoS-). Interestingly, 6 isolates possessing both exoU and exoS were detected, which is a notable finding since exoU and exoS appear to be mutually exclusive in different P. aeruginosa populations in human and environmental isolates (Wiehlmann et al, 2007;Selezska et al, 2012).…”

Population Structure and Antimicrobial Susceptibility of Both Nonpersistent and Persistent Pseudomonas aeruginosa Isolates Recovered from Cystic Fibrosis Patients

“…olecular typing tools applied to Pseudomonas aeruginosa isolates recovered from cystic fibrosis (CF) patients have demonstrated not only local epidemiological differences (1)(2)(3)(4) but also the spread of particular multiresistant clones through different CF units (5)(6)(7)(8) and the in vivo evolution of single clones involving multilocus sequence type (MLST) shifts (9). Nevertheless, studies addressing differences in terms of population structure between nonpersistent and persistent isolates from CF patients have not yet been reported.…”

Homeostasis and Catabolism of Choline and Glycine Betaine: Lessons from Pseudomonas aeruginosa

“…The cited studies also pointed out that virulence factor production and resistance to phagocytes are also not indicative of it being a pathogen, but as with many environmental bacteria, a set of responses likely evolved to evade phagocytic eukaryotes such as amoeba. P. aeruginosa is prevalent in the environment primarily as a member of aquatic communities, including freshwater, estuarine, and marine systems (1,(6)(7)(8)(9), and in rivers appears to be more prevalent in human-impacted stretches (10). P. aeruginosa can be isolated from the soil, but is often absent or at low abundance in many soil samples (10,11).…”

“…P. aeruginosa is prevalent in the environment primarily as a member of aquatic communities, including freshwater, estuarine, and marine systems (1,(6)(7)(8)(9), and in rivers appears to be more prevalent in human-impacted stretches (10). P. aeruginosa can be isolated from the soil, but is often absent or at low abundance in many soil samples (10,11). However, during liquid broth enrichment of cultures from soil and aquatic environments, P. aeruginosa and many of its nonpathogenic relatives such as P. putida, P. fluorescens, and P. stutzeri are capable of rapid growth and often outcompete numerically abundant microbes from the original system, leading them to be categorized as optimal exploiters of nutrient pulses (12,13).…”