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PubMed1992

Characteristics of Pseudomonas aeruginosa strains causing septicemia in a Spanish hospital 1981-1990.

The epidemiological and biochemical characteristics of Pseudomonas aeruginosa strains causing septicemia in a Spanish hospital over a ten-year period (1981-1990) were analyzed. A total of 207 episodes, corresponding to 0.7 episodes per 1,000 inpatients and 3.2% of the total number of episodes of septicemia, were registered. Males were more often affected than females (rate 3.2:1). The respiratory (24.6%) and urinary (21.2%) tracts were the main portals of entry, while haematologic and solid tumours (15.4%) were the most frequent underlying diseases. More than 86% of the strains were susceptible to ceftazidime, mezlocillin, piperacillin and amikacin. Seventy strains were subjected to typing and analysis of virulence factors. Serotypes O:6, O:11 and O:2 could be considered endemic (each present in more than 11.4% of strains). Pyocin typing, antibiotyping and resistotyping were preferred as secondary typing methods to phage typing and plasmid profile analysis. The combination of methods revealed a large diversity of strains although some clusters predominated. More than 80% of the strains produced several exoenzymes, possessed pyoverdin and showed haemolytic activity, and all except one showed serum resistance. All strains were susceptible to silver and more than 80% to mercury and boron, but all were resistant to iodine.

Adolescent↗
PubMed1983

Epidemiological studies of Pseudomonas aeruginosa infections in leg ulcers.

A 6-month prospective study was carried out in an angiology ward on patients with leg ulcers. Pseudomonas aeruginosa was isolated from about half of the samples from the patients. Of the isolates, 85 were serotyped, fingerprinted as to passive pyocin sensitivity and characterized for antibiotic susceptibility pattern. According to all criteria, the isolates belonged to six strains, two of which were clearly epidemic: one infected 11 patients yielding 52 identical isolates, the other infected 4 patients (19 isolates).

Adult↗
PubMed1982

Amikacin, gentamicin and tobramycin resistant Pseudomonas aeruginosa in a leukaemic ward. Epidemiology and genetic studies.

Four patients in a leukaemic ward were infected with multi-resistant Pseudomonas aeruginosa. Similar organisms were found in the environment and it appeared that lapses in aseptic routine contributed to the outbreak. Serological, bacteriophage and pyocin-typing revealed that a fifth patient was infected with a distinct strain, but agarose gel electrophoresis indicated that all patient and environmental strains carried the same plasmid. The plasmid had a molecular weight of 47 (s.d. +/- 2) X 10(6) dal and was transfer deficient. It conferred resistance to carbenicillin, gentamicin, kanamycin, streptomycin, sulphonamide, tetracycline and tobramycin and determined an aminoglycoside adenylyltransferase active against amikacin in-vitro and not in-vivo. Spread of this non-transferable plasmid to a different Ps. aeruginosa strain and dissemination of multi-resistant organisms led to serious infections.

Adult↗
PubMed1987

Acquisition of endemic Pseudomonas aeruginosa on an intensive therapy unit.

During a 9-month period, patients, staff and environment were monitored in order to trace the source of endemic Pseudomonas aeruginosa on our intensive therapy unit (ITU). Of 81 patients studied, 14 (17%) acquired 15 different pyocin types while on the ITU. The most frequent site of colonization was the rectum (11 patients). Rectal strains subsequently appeared in urine (two patients), wound (one) and sputum (four) of six patients. Three episodes of cross-infection (wound (two), urine (one] occurred without development of rectal colonization. Strains isolated from the environment and staff were not implicated. While gastrointestinal carriage of P. aeruginosa may not be detected on admission to the ITU, excessive use of antibiotics may be responsible for apparent acquisition of the organism followed by endogenous transfer of the rectal strains to other sites of the body.

Cross Infection↗
PubMed1992

Epidemiology of Pseudomonas aeruginosa in an intensive care unit using selective decontamination of the digestive tract.

Selective decontamination of the digestive tract (SDD) aims to reduce the rate of nosocomial infections in critical care patients. Pseudomonas spp. are common nosocomial pathogens and in this study isolates collected from patients and the environment during an SDD trial were examined. The study enrolled 161 SDD cases and 170 controls. Pseudomonads were isolated from 27% of SDD patients and 30% of controls. SDD partially suppressed colonization in the 'gastro-respiratory' mucosae but not in the rectum. A total of 108 isolates of pseudomonads were recovered from the environment. Resistance in rectal isolates was minimal but isolates from 'gastro-respiratory' sites showed increasing aminoglycoside resistance. Eighty-six per cent of aminoglycoside-resistant isolates from both patient groups and environment were pyocine type 1x. Episodes of infection were reduced in the SDD patients (6) compared with the controls (16), aminoglycoside-resistant strains being associated with zero episodes in SDD patients but with five in the control group.

Cross Infection↗
PubMed1994

Lack of association between clinical and environmental isolates of Pseudomonas aeruginosa in hospital wards.

Seventy-three environmental and clinical isolates of Pseudomonas aeruginosa recovered from a single hospital over a 6-month period were compared for epidemiological type characteristics. Environmental isolates were obtained from sinks, taps and water, in rooms where patients were treated. The strains represented only six O-antigenic types and 8.2% of them were not typable. Serotype 011 was most frequent in the environment, whereas serotypes 06, 012 and 02,5 predominated among clinical isolates. More than 60% of all isolates belonged to four pyocin types (1, 10, 33 and 45), and approximately 80% were phage typable. Environmental isolates were more sensitive to antibiotics than clinical isolates. There was little correspondence between the types of strains of P. aeruginosa isolated from patients and those isolated from the environment. However, isolates of identical type were frequently recovered from different patients within the same clinic and were found to be related in time and location. We conclude that the environment was not an important source of P. aeruginosa infection and that transfer of organisms was mainly from patient-to-patient.

Bacterial Typing Techniques↗
PubMed1995

Investigation of a nosocomial outbreak of Pseudomonas aeruginosa pneumonia in an intensive care unit by random amplification of polymorphic DNA assay.

From July to September 1993 in the intensive care unit of the Royal Victoria Hospital there were 10 cases of pneumonia associated with sputum culture of Pseudomonas aeruginosa. The isolates had an identical biotype and pyocine typing profile. The same strain of P. aeruginosa was recovered from the sink plug-hole in two rooms, and the tap handles and ventilator tubing in a third room. All strains were retrospectively typed by the random amplification of polymorphic DNA (RAPD) method using a 26-mer oligonucleotide primer, and were identical in profile. Recommendations to medical and nursing staff included secretion isolation precautions, terminal disinfection after patient discharge, use of disposable vinyl gloves by hospital staff for all body substance contacts, thorough handwashing with 4% chlorhexidine gluconate before and after dealing with all patient contacts, and prompt, appropriate antibiotic treatment for P. aeruginosa pneumonia. RAPD is a simple and effective method to determine the relatedness of P. aeruginosa isolates, and typing results are available within a single working day; thus dramatically increasing its clinical relevance over existing molecular methods.

Bacterial Typing Techniques↗
PubMed1993

Laboratory data from the surveillance of a burns ward for the detection of hospital infection.

Nosocomial infection is a major problem affecting many hospital personnel and patients. Surveillance of intensive care areas such as burns wards is important due to the immunocompromised status of the patients. Since infection has been found to be a major cause of death in our burns ward, bacteriological surveillance of the area was carried out over a 1-year period. This indicated the various sources of infection, which included a contaminated container of disinfectant, and transient pathogenic flora on one of the staff members involved in changing dressings. Pseudomonas aeruginosa was the most commonly isolated pathogen from infected wounds as well as from the blood of patients developing sepsis. Autogenous spread of this organism was confirmed by similar pyocin typing results of the strains isolated from wounds, blood and faeces of the patients. Necessary changes were implemented based on these findings and the infection rate was reduced remarkably. The results suggested that strict vigilance by the personnel involved in the care of burns patients reduces the incidence of invasive sepsis and shortens the hospital stay.

Adolescent↗
PubMed1977

Reservoirs of pseudomonas in an intensive care unit for newborn infants: mechanisms of control.

Potential reservoirs of pseudomonas within a neonatal ICU were evaluated. Colonization of infants by the same pseudomonas pyocin types could be classified as a cluster colonization (occurring over three to ten days), or serial colonization (occurring over longer times). Hands of personnel, sink surfaces, and solutions used to rinse nasopharyngeal catheters were identified as the principle reservoirs. Utilization of a liquid iodophor agent for hand washing and of acetic acid for rinsing suction catheters was associated with a significant reduction in the histologic evidence of sepsis and of pneumonia observed among autopsied infants.

Bacteriological Techniques↗
PubMed1982

Does pseudomonas cross-infection occur between cystic-fibrosis patients.

Over a 12-months period respiratory Pseudomonas aeruginosa isolated from CF patients were typed by serology and pyocin production to determine whether cross-infection was occurring. Results of typing were interpreted in relation to the degree of contact patients had with each other. One strain appeared in 4 unrelated patients. However, since none of these patients had been in contact with each other the strains considered to have been acquired from the environment. Each of six pairs of siblings shared the same strain, but the pairs of strains were distinct from each other. These results suggest that the environment is the most important source of Pseudomonas strains for CF patients and that for cross-infection to occur prolonged intimate contact is required.

Adolescent↗
PubMedDate not supplied

Morphology of Pseudomonas aeruginosa typing phages of the Lindberg set.

Eighteen phages were studied by electron microscopy. They belonged to eight morphotypes representing the Myoviridae, Siphoviridae and Podoviridae families of tailed phages. Twelve phages were members of known species and six phages belonged to three new species. Results correlated closely with serological and DNA-DNA hybridization data. Induced and non-induced propagating bacteria were investigated for lysogeny. All strains produced R-type pyocins, phage-like particles or inhibitory reactions. The identity of typing phages should be controlled periodically.

Bacteriophages↗
PubMed1981

An outbreak of otitis externa in competitive swimmers due to Pseudomonas aeruginosa.

Pseudomonas aeruginosa was isolated from the ears of 18 of the 25 members of a team of competitive swimmers who complained of painful discharging ears. This group of swimmers trained twice daily in the pool, in the early morning and late afternoon. In contrast swabbing of the ears of a similar group of 54 competitive swimmers who used the pool only in the afternoon revealed only one swimmer with P. aeruginosa. Investigation of the swimming pool revealed that chlorination was often inadequate when the first group of swimmers were training in the early morning. Strains of P. aeruginosa were isolated from various sites around the pool and from the bag of a vacuum used to clean the pool. Pyocin typing, serotyping and phage typing were performed on all isolates. The dominant strain recovered from the swimmers' ears was found to be almost identical to that from the vacuum bag and belonged to serotype 0--11 which has been particularly associated with outbreaks of P. aeruginosa infection in whirlpools in the United States. These results support the hypothesis that there is a direct correlation between the development of otitis externa and swimming in water contaminated with P. aeruginosa.

Adolescent↗
PubMed1982

Hand carriage of aerobic gram-negative rods may not be transient.

In order to determine whether hand carriage of aerobic Gram-negative rods is continuous we used the glove-handwash technique to sample the hands of two groups (four each) of health care workers with normal hands (surgical intensive care unit, medical ward) and one group (four) with hand dermatitis (HD) and a group (five) of control subjects -- secretaries with no exposure to patients. Each subject was sampled repeatedly over three to six weeks. The mean number of samples for each group was 25.2, 23.2, 19.8 and 25.8 respectively. The HD group had more samples positive for aerobic Gram-negative rods than did the other two groups of health care workers while the control group had more samples positive than any of the three health care groups. Using various typing schemes and the following definition of continuous carriage (the isolation of an organism of the same serotype, pyocin type or biotype from more than two handwash samples) we found that 4 of 11 subjects from whom Klebsiella pneumoniae was isolated carried this organism continuously; 2 of 3 carried Pseudomonas aeruginosa continuously and 4 of 5 of the control subjects carried the same biotype of Enterobacter agglomerans continuously. We conclude that continuous hand carriage of aeroic Gram-negative rods is common and, among health care workers, those with hand dermatitis carry Gram-negative rods more frequently and in greater numbers than health care workers without hand dermatitis.

Bacteria↗
PubMedDate not supplied

Investigation of an epidemic of multi-drug resistant Pseudomonas aeruginosa.

Inter- and intrahospital epidemics of nosocomial infections due to gram-negative bacilli resistant to many antimicrobials have been well-documented. Prospective studies on the use of isolation along with epidemiologic analysis and appropriate environmental control have been lacking. In the six-month period from November 1978 to April 1979 Pseudomonas aeruginosa (MDR) resistant to all antibiotics except amikacin was isolated from 15 patients. This organism had not previously been seen in our hospital. Epidemiologic assessment of infected patients revealed that nine of 15 patients had contact either with a previously infected case or contaminated area. All strains of P. aeruginosa were identical by pyocin typing and antibiogram. The organism was present in an environmental reservoir, the urine graduated cylinder, and was found in three of eight receptacles (p = 0.002 vs. other environmental cultures). A case control study of patient risk factors showed aminoglycoside use, other antibiotic use, surgery, intravenous lines, Foley catheter use and mechanical ventilation to be no more frequent in cases than controls. The use of aminoglycosides in only 40% of cases suggests that antibiotic pressure was not the sole factor in perpetuating the epidemic.

Aminoglycosides↗
PubMed1989

Multiresistant serotype O 12 Pseudomonas aeruginosa: evidence for a common strain in Europe.

A survey was made of serotype association and multiple antibiotic resistance in strains of Pseudomonas aeruginosa in Europe. Of 208 epidemiologically distinct strains from 16 laboratories in 10 countries, 48 were resistant to carbenicillin (MIC greater than 128 micrograms/ml) and gentamicin (MIC greater than 4 micrograms/ml), and 12 of these strains were of serotype O 12. Representative O 12 strains from different countries were compared with two multiresistant O 12 strains isolated 5 years apart, from a British burns unit and the antibiotic sensitive serotype reference strain. All O 12 strains were similar by phage and pyocin typing but lysogenic phage profiles indicated that two strains (the later burns isolate and the serotype strain) were distinct from the others. Electrophoretic characterization of outer membrane proteins, lipopolysaccharides and esterase enzymes corroborated the relationship of the strains and restriction fragment length polymorphism of DNA fragments hybridized with a cDNA probe copy of rRNA from P. aeruginosa provided further proof of their relatedness. We propose that the uniformity of characters of multiresistant O 12 P. aeruginosa in Europe is suggestive of a common origin for the strains.

Anti-Bacterial Agents↗
PubMed1993

Outbreak of Pseudomonas aeruginosa infections in a surgical intensive care unit: probable transmission via hands of a health care worker.

Pseudomonas aeruginosa was isolated from nine patients (16.2 isolations/1,000 patient-days) in a surgical intensive care unit during an outbreak in November 1990; this rate of isolation was three times higher than that noted previously on this unit. Three patients were infected with the same strain, as defined by identical serotypes, pyocin types, and contour-clamped homogeneous electric field (CHEF) electrophoresis patterns of digested genomic DNA. The hands of 80 health care workers were cultured, and a strain of P. aeruginosa identical to that infecting the three patients was isolated from the hands of a nurse providing care to all three. Environmental surfaces, medical devices, and ward stock supplies were cultured; none of these cultures yielded this strain. No clusters of infection with this strain or other strains of P. aeruginosa were observed after compliance with hand-washing and universal precautions was reemphasized. Thus this outbreak was linked to the carriage of P. aeruginosa on the hands of a health care worker. It could not be determined definitively whether this carriage was the source of the cluster or a consequence of it. However, the geographic and temporal clustering of carriage with an outbreak due to a strain of an apparently identical molecular type underlines the importance of routine hand washing between contacts with different patients.

Adult↗
PubMed1995

Pseudomonas aeruginosa folliculitis due to non-O:11 serogroups: acquisition through use of contaminated synthetic sponges.

We describe the features of 13 cases of Pseudomonas aeruginosa folliculitis (eight of which occurred sporadically and five of which resulted from two family outbreaks) that developed subsequent to the use of commercial synthetic sponges for bathing. On the basis of O serogrouping and pyocin typing and subtyping, the strains recovered from the skin lesions were found to be identical to those isolated from household shower water and sponges. P. aeruginosa folliculitis is commonly caused by the serogroup O:11; The serogroups described in this study are rare causative agents of this type of skin infection. We believe that this is the first report of P. aeruginosa folliculitis due to serogroups O:3 and O:16.

Adult↗
PubMed1990

Novel resistance to imipenem associated with an altered PBP-4 in a Pseudomonas aeruginosa clinical isolate.

A Pseudomonas aeruginosa (isolate 416) from a patient with pneumonia, was initially susceptible to imipenem (MIC: 2 mg/l) but became resistant to this antibiotic (isolate 470, MIC: 32 mg/l) during imipenem therapy. Treatment failed. No parallel increases in MIC were observed for other antimicrobials tested. Isolates 416 and 470 shared the same pyocin type and serotype, produced small amounts of an inducible beta-lactamase, and had similar lipopolysaccharide compositions. On electrophoresis of outer membrane proteins, the porin F, identified by the monoclonal antibody MA4-4, was expressed similarly by the two isolates but the production of one band (apparent molecular weight: 47,000) was diminished in isolate 470. [14C]-Imipenem labelling of intact cells proceeded more slowly in 470 than in 416, especially when bacterial cells were treated by antibody MA4-4 to block the porin F channel. [14C]-Imipenem labelling of penicillin binding proteins (PBP) showed that the band identified as PBP-4 bound markedly less radioactivity in isolate 470 than in 416. After isolate 470 was passaged several times in antibiotic-free broth, the imipenem MIC was decreased from 32 to 8 mg/l, and the [14C]-imipenem PBP pattern recovered the initial profile as exhibited by isolate 416. Two resistance mechanisms, affecting imipenem electively, could have combined their effect in the post-therapy isolate, altered target protein and reduced permeability.

Animals↗