Pseudomonas aeruginosa Isolates from Spanish Children: Occurrence in Faecal Samples, Antimicrobial Resistance, Virulence, and Molecular Typing

Abstract

Pseudomonas aeruginosa is a major opportunistic human pathogen, responsible for nosocomial infections and infections in patients with impaired immune systems. Little data exist about the faecal colonisation by P. aeruginosa isolates in healthy humans. The occurrence, antimicrobial resistance phenotype, virulence genotype, and genetic lineages of P. aeruginosa from faecal samples of children from two different Spanish regions were characterised. Seventy-two P. aeruginosa were isolated from 1,443 faecal samples. Low antimicrobial resistance levels were detected: ceftazidime (8%), cefepime (7%), aztreonam (7%), gentamicin (3%), ciprofloxacin (1%), and imipenem (1%); susceptibility to meropenem, amikacin, tobramycin, levofloxacin, and colistin. Four multidrug-resistant strains were found. Important differences were detected between both geographical regions. Forty-one sequence types were detected among the 48 tested strains. Virulence and quorum sensing genes were analysed and 13 virulotypes were detected, being 26 exoU-positive strains. Alteration in protein OprD showed eight different patterns. The unique imipenem-resistant strain showed a premature stop codon in OprD. Intestinal colonisation by P. aeruginosa, mainly by international clones (as ST244, ST253, and ST274), is an important factor for the systemic infections development and the environmental dissemination. Periodic active surveillance is useful to identify these community human reservoirs and to control the evolution of antibiotic resistance and virulence activity.

High prevalence of atypical virulotype and genetically diverse background among Pseudomonas aeruginosa isolates from a referral hospital in the Brazilian Amazon

“…exoS results are in accordance with the hypothesis of a wider distribution of this gene due to its chromosomal nature. Nevertheless, the fact of in nearly 30% of our isolates exoT and exoY genes were not detected and a significant absence of exoY gene among BSI isolates demonstrate a contrary trend to the hypothesis of their universal distribution among P. aeruginosa strains, as well as, several studies that rarely report absence of these genes (P = 0.0435) ( Table 2) [13,15,16,55,56,70].…”

“…The high prevalence of the aprA gene is in line with other studies [1,13,56,59], highlighting the importance of zinc-metalloprotease secreted by T1SS, which has functions related to invasion, causing collagen and fibrinogen degradation in synergy with T2SS elastases, and…”

“…It is likely that inter-hospital transit patients and/or who spend short periods in the hospital environment, as well as healthcare professionals, carry isolates and insert them in the hospital environment, and consequently causing infections in ICU patients because of numerous risk factors, such as immunosuppression conditions and virulence potential of isolates. Our data also corroborate the hypothesis of epidemic non-clonal population structure of P. aeruginosa, indicating the dispersion of global HRC in hospitals settings and the continuous description of new P. aeruginosa STs worldwide [15,23,55,56,76,85,86].…”

“…reports that indicates a high prevalence and conserved nature of the P. aeruginosa genome regarding the presence of virulence-related genes, variations in virulence patterns are observed in isolates from different geographic areas and settings, highlighting the need to investigate different markers among distinct P. aeruginosa populations [1,13,23,35,55,56]. The algD gene was detected in 98.1% of isolates, while absence of algU was noted in more than 53.0%.…”

Molecular Epidemiology of Multi-Drug Resistant Pseudomonas aeruginosa Isolates from Hospitalized Patients in Greece

“…Several typing methods have been used to study the evolution and genetic heterogeneity of P. aeruginosa because it is characterized by high genetic diversity [8][9][10][11][12]. In recent years, the development of Whole Genome Sequencing has given rise to the study of Multi-Drug Resistant (MDR) P. aeruginosa's molecular epidemiology [13,14], but this is a high cost method demanding specialized staff making it difficult for many laboratories to implement.…”