Ceftazidime resistance in Pseudomonas aeruginosa is multigenic and complex.

Pseudomonas aeruginosa causes a wide range of severe infections. Ceftazidime, a cephalosporin, is a key antibiotic for treating infections but a significant proportion of isolates are ceftazidime-resistant. The aim of this research was to identify mutations that contribute to resistance, and to quantify the impacts of individual mutations and mutation combinations.

Rapid fluoroquinolone resistance detection in using mismatch amplification mutation assay-based real-time PCR.

Antimicrobial resistance (AMR) is an ever-increasing global health concern. One crucial facet in tackling the AMR epidemic is earlier and more accurate AMR diagnosis, particularly in the dangerous and highly multi-drug-resistant ESKAPE pathogen, . We aimed to develop two SYBR Green-based mismatch amplification mutation assays (SYBR-MAMAs) targeting GyrA T83I (248) and GyrA D87N, D87Y and D87H (259).

Express Yourself: Quantitative Real-Time PCR Assays for Rapid Chromosomal Antimicrobial Resistance Detection in Pseudomonas aeruginosa.

The rise of antimicrobial-resistant (AMR) bacteria is a global health emergency. One critical facet of tackling this epidemic is more rapid AMR diagnosis in serious multidrug-resistant pathogens like Pseudomonas aeruginosa. Here, we designed and then validated two multiplex quantitative real-time PCR (qPCR) assays to simultaneously detect differential expression of the resistance-nodulation-division efflux pumps MexAB-OprM, MexCD-OprJ, MexEF-OprN, and MexXY-OprM, the AmpC β-lactamase, and the porin OprD, which are commonly associated with chromosomally encoded AMR.

The Effects of Sub-inhibitory Antibiotic Concentrations on : Reduced Susceptibility Due to Mutations.

chronically infects in the lungs of people with cystic fibrosis and other forms of lung disease. Infections are treated with antibiotics, but over time, the bacteria acquire mutations that reduce their antibiotic susceptibility. The effects of inhibitory amounts of antibiotics in selecting for antibiotic-resistant mutants have been well studied.

Emergence and impact of oprD mutations in Pseudomonas aeruginosa strains in cystic fibrosis.

Background: Antimicrobial resistance in cystic fibrosis (CF) Pseudomonas aeruginosa airway infection is complex and often attributed to chromosomal mutations. How these mutations emerge in specific strains or whether particular gene mutations are clinically informative is unclear. This study focused on oprD, which encodes an outer membrane porin associated with carbapenem resistance when it is downregulated or inactivated.

Genomic and phenotypic comparison of environmental and patient-derived isolates of suggest that antimicrobial resistance is rare within the environment.

Patient-derived isolates of the opportunistic pathogen are frequently resistant to antibiotics due to the presence of sequence variants in resistance-associated genes. However, the frequency of antibiotic resistance and of resistance-associated sequence variants in environmental isolates of has not been well studied. Antimicrobial susceptibility testing (ciprofloxacin, ceftazidime, meropenem, tobramycin) of environmental (=50) and cystic fibrosis (=42) isolates was carried out.

Transmission of bacteria in bronchiectasis and chronic obstructive pulmonary disease: Low burden of cough aerosols.

Background And Objective: Aerosol transmission of Pseudomonas aeruginosa has been suggested as a possible mode of respiratory infection spread in patients with cystic fibrosis (CF); however, whether this occurs in other suppurative lung diseases is unknown. Therefore, we aimed to determine if (i) patients with bronchiectasis (unrelated to CF) or chronic obstructive pulmonary disease (COPD) can aerosolize P. aeruginosa during coughing and (ii) if genetically indistinguishable (shared) P.

Correction: Within-host whole genome analysis of an antibiotic resistant Pseudomonas aeruginosa strain sub-type in cystic fibrosis.

[This corrects the article DOI: 10.1371/journal.pone.

Expression of Pseudomonas aeruginosa Antibiotic Resistance Genes Varies Greatly during Infections in Cystic Fibrosis Patients.

The lungs of individuals with cystic fibrosis (CF) become chronically infected with that is difficult to eradicate by antibiotic treatment. Two key antibiotic resistance mechanisms are the AmpC β-lactamase that degrades β-lactam antibiotics and MexXYOprM, a three-protein efflux pump that expels aminoglycoside antibiotics from the bacterial cells. Levels of antibiotic resistance gene expression are likely to be a key factor in antibiotic resistance but have not been determined during infection.

Whole genome sequencing reveals the emergence of a Pseudomonas aeruginosa shared strain sub-lineage among patients treated within a single cystic fibrosis centre.

Background: Chronic lung infections caused by Pseudomonas aeruginosa are a significant cause of morbidity and mortality in people with cystic fibrosis (CF). Shared P. aeruginosa strains, that can be transmitted between patients, are of concern and in Australia the AUST-02 shared strain is predominant in individuals attending CF centres in Queensland and Western Australia.

Cystic fibrosis pathogens survive for extended periods within cough-generated droplet nuclei.

The airborne route is a potential pathway in the person-to-person transmission of bacterial strains among cystic fibrosis (CF) populations. In this cross-sectional study, we investigate the physical properties and survival of common non- CF pathogens generated during coughing. We conclude that Gram-negative bacteria and are aerosolised during coughing, can travel up to 4 m and remain viable within droplet nuclei for up to 45 min.

Antibiotic perturbation of mixed-strain Pseudomonas aeruginosa infection in patients with cystic fibrosis.

Background: Pulmonary exacerbations in cystic fibrosis (CF) remain poorly understood and treatment is usually targeted at Pseudomonas aeruginosa. Within Australia a predominant shared P. aeruginosa strain (AUST-02) is associated with greater treatment needs.

Face Masks and Cough Etiquette Reduce the Cough Aerosol Concentration of Pseudomonas aeruginosa in People with Cystic Fibrosis.

Rationale: People with cystic fibrosis (CF) generate Pseudomonas aeruginosa in droplet nuclei during coughing. The use of surgical masks has been recommended in healthcare settings to minimize pathogen transmission between patients with CF.

Objectives: To determine if face masks and cough etiquette reduce viable P.

Within-host whole genome analysis of an antibiotic resistant Pseudomonas aeruginosa strain sub-type in cystic fibrosis.

A Pseudomonas aeruginosa AUST-02 strain sub-type (M3L7) has been identified in Australia, infects the lungs of some people with cystic fibrosis and is associated with antibiotic resistance. Multiple clonal lineages may emerge during treatment with mutations in chromosomally encoded antibiotic resistance genes commonly observed. Here we describe the within-host diversity and antibiotic resistance of M3L7 during and after antibiotic treatment of an acute pulmonary exacerbation using whole genome sequencing and show both variation and shared mutations in important genes.

The changing prevalence of pulmonary infection in adults with cystic fibrosis: A longitudinal analysis.

Background: Increased patient longevity and aggressive antibiotic treatment are thought to impact on the microbial composition of the airways of adults with cystic fibrosis (CF). In this study, we sought to determine if a temporal change in the airway microbiology of adults with CF has occurred over time.

Methods: Longitudinal analysis of sputum microbiology results was undertaken on patients attending a large adult CF centre.

A Novel Method and Its Application to Measuring Pathogen Decay in Bioaerosols from Patients with Respiratory Disease.

This work aimed to develop an in vivo approach for measuring the duration of human bioaerosol infectivity. To achieve this, techniques designed to target short-term and long-term bioaerosol aging, were combined in a tandem system and optimized for the collection of human respiratory bioaerosols, without contamination. To demonstrate the technique, cough aerosols were sampled from two persons with cystic fibrosis and chronic Pseudomonas aeruginosa infection.

Methicillin-resistant Staphylococcus aureus acquisition in healthcare workers with cystic fibrosis: a retrospective cross-sectional study.

Background: People with cystic fibrosis (CF) may work in healthcare settings risking nosocomial pathogen acquisition. The aim of this study was to determine the incidence of methicillin-resistant Staphylococcus aureus (MRSA) infection in adult healthcare workers with CF (HCWcf).

Methods: Data was collected in this observational study on MRSA acquisition from 405 CF patients attending an adult CF centre in Australia between 2001-2012.

Pseudomonas aeruginosa antibiotic resistance in Australian cystic fibrosis centres.

Background And Objective: In cystic fibrosis (CF), chronic Pseudomonas aeruginosa infection is associated with increased morbidity, antibiotic treatments and mortality. By linking Australian CF registry data with a national microbiological data set, we examined the association between where treatment was delivered, its intensity and P. aeruginosa antibiotic resistance.

Genotypic Diversity within a Single Pseudomonas aeruginosa Strain Commonly Shared by Australian Patients with Cystic Fibrosis.

In cystic fibrosis (CF), Pseudomonas aeruginosa undergoes intra-strain genotypic and phenotypic diversification while establishing and maintaining chronic lung infections. As the clinical significance of these changes is uncertain, we investigated intra-strain diversity in commonly shared strains from CF patients to determine if specific gene mutations were associated with increased antibiotic resistance and worse clinical outcomes. Two-hundred-and-one P.

Pseudomonas aeruginosa genotypes acquired by children with cystic fibrosis by age 5-years.

Background: We describe Pseudomonas aeruginosa acquisitions in children with cystic fibrosis (CF) aged ≤5-years, eradication treatment efficacy, and genotypic relationships between upper and lower airway isolates and strains from non-CF sources.

Methods: Of 168 CF children aged ≤5-years in a bronchoalveolar lavage (BAL)-directed therapy trial, 155 had detailed microbiological results. Overall, 201/271 (74%) P.

Molecular surveillance for carbapenemase genes in carbapenem-resistant Pseudomonas aeruginosa in Australian patients with cystic fibrosis.

The aim of this study was to assess the prevalence of acquired carbapenemase genes amongst carbapenem non-susceptible Pseudomonas aeruginosa isolates in Australian patients with cystic fibrosis (CF). Cross-sectional molecular surveillance for acquired carbapenemase genes was performed on CF P. aeruginosa isolates from two isolate banks comprising: (i) 662 carbapenem resistant P.

A comparison of two informative SNP-based strategies for typing Pseudomonas aeruginosa isolates from patients with cystic fibrosis.

Background: Molecular typing is integral for identifying Pseudomonas aeruginosa strains that may be shared between patients with cystic fibrosis (CF). We conducted a side-by-side comparison of two P. aeruginosa genotyping methods utilising informative-single nucleotide polymorphism (SNP) methods; one targeting 10 P.