Epidemiology of Pseudomonas aeruginosa in a tertiary referral teaching hospital.
ABSTRACT A genotypically indistinguishable strain of Pseudomonas aeruginosa (Australian epidemic strain III: AES III) has previously been found in a proportion of adults with cystic fibrosis (CF) in Tasmania, Australia. The aim of this study was to identify a source of these infections within the major tertiary referral hospital for the State of Tasmania, and to determine if this strain could be isolated from settings other than the CF lung. A total of 120 isolates of P. aeruginosa were collected from clinical and environmental sources within the hospital and from environmental locations in the hospital vicinity. These isolates were genotyped by random amplification of polymorphic DNA (RAPD)-polymerase chain reaction (PCR) and antimicrobial susceptibility testing was performed using the Clinical and Laboratory Standards Institute method. Confirmation of similar genotypes identified by RAPD-PCR was performed using pulsed-field gel electrophoresis with restriction enzyme SpeI. AES III was not recovered from any source other than the respiratory secretions of CF patients. P. aeruginosa in the non-CF settings was found to be panmictic, and no cross-infection or acquisition of hospital environment strains by patients was observed.
Article: Emergence of Pseudomonas aeruginosa cross-infection in children with cystic fibrosis attending an Iranian referral pediatric center.[show abstract] [hide abstract]
ABSTRACT: This study was carried out with the objective of determining the genomic variability of P. aeruginosa strains isolated from patients suffering from cystic fibrosis or from environmental cultures collected from different locations in the unit they admitted. A total of 57 clinical and environmental P. aeruginosa isolates were genotyped by enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR), and antimicrobial susceptibility testing was performed using the Clinical and Laboratory Standards Institute method. One predominant ERIC profile (type A) was identified in 46 strains (81% of all typed isolates) which was responsible for thirty-nine of 44 clinical isolates (89%) and 7 of 13 environmental isolates (54%). All clinical isolates were susceptible to piperacillin-tazobactam, ceftazidime and cefepime followed by ticarcillin, aztreonam, amikacin and tobramycin (96.5%). In our country CF patients are not segregated from other patients, and transmission of bacteria between these patients and other patients might occur in the wards via personal contact or contaminated environment. Future evaluation for policy of patient segregation is necessary and the elimination of contaminated sources and control of environmental spread and recurrent contamination risk is needed.Iranian Journal of Microbiology 09/2012; 4(3):124-9.
Article: The population genetics of Pseudomonas aeruginosa isolates from different patient populations exhibits high-level host specificity.[show abstract] [hide abstract]
ABSTRACT: To determine whether highly prevalent P. aeruginosa sequence types (ST) in Dutch cystic fibrosis (CF) patients are specifically linked to CF patients we investigated the population structure of P. aeruginosa from different clinical backgrounds. We first selected the optimal genotyping method by comparing pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and multilocus variable number tandem-repeat analysis (MLVA). Selected P. aeruginosa isolates (n = 60) were genotyped with PFGE, MLST and MLVA to determine the diversity index (DI) and congruence (adjusted Rand and Wallace coefficients). Subsequently, isolates from patients admitted to two different ICUs (n = 205), from CF patients (n = 100) and from non-ICU, non-CF patients (n = 58, of which 19 were community acquired) were genotyped with MLVA to determine distribution of genotypes and genetic diversity. Congruence between the typing methods was >79% and DIs were similar and all >0.963. Based on costs, ease, speed and possibilities to compare results between labs an adapted MLVA scheme called MLVA9-Utrecht was selected as the preferred typing method. In 363 clinical isolates 252 different MLVA types (MTs) were identified, indicating a highly diverse population (DI = 0.995; CI = 0.993-0.997). DI levels were similarly high in the diverse clinical sources (all >0.981) and only eight genotypes were shared. MTs were highly specific (>80%) for the different patient populations, even for similar patient groups (ICU patients) in two distinct geographic regions, with only three of 142 ICU genotypes detected in both ICUs. The two major CF clones were unique to CF patients. The population structure of P. aeruginosa isolates is highly diverse and population specific without evidence for a core lineage in which major CF, hospital or community clones co-cluster. The two genotypes highly prevalent among Dutch CF patients appeared unique to CF patients, suggesting specific adaptation of these clones to the CF lung.PLoS ONE 01/2010; 5(10):e13482. · 4.09 Impact Factor