Cross-infection with Pseudomonas aeruginosa in a neonatal intensive care unit characterized by polymerase chain reaction fingerprinting.
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Bacterial Typing Techniques↗
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Protection against pulmonary infection with Pseudomonas aeruginosa following immunization with P. aeruginosa-pulsed dendritic cells.
To develop a Pseudomonas aeruginosa vaccine that allows the host immune system to select the antigens, we hypothesized that dendritic cells (DC) pulsed with P. aeruginosa would induce protective immunity against pulmonary infections with P. aeruginosa. Incubation of murine bone marrow-derived DC with P. aeruginosa in vitro led to uptake of P. aeruginosa and activation of the DC. Spleen-derived CD4(+) cells from mice immunized with P. aeruginosa-pulsed DC showed increased proliferation, demonstrating that DC pulsed with P. aeruginosa were capable of eliciting a P. aeruginosa-specific immune response. To evaluate if P. aeruginosa-pulsed DC can induce protective immunity against P. aeruginosa pulmonary infection, DC incubated with P. aeruginosa in vitro were administered systemically to syngeneic mice, and the mice were then challenged by intrapulmonary infection with P. aeruginosa (5 x 10(4) CFU/mouse) 13 days later. Unimmunized control mice and mice who had previously received naive DC or DC stimulated with lipopolysaccharide or Escherichia coli died within 72 h. In contrast, 45% of mice receiving P. aeruginosa-pulsed DC demonstrated prolonged survival (>14 days). Finally, DC-pulsed with heat-inactivated P. aeruginosa protected CD8(-/-) but not CD4(-/-) mice, demonstrating that CD4(+) T cells were required for the DC pulsed with P. aeruginosa to induce protective immunity.
Animals↗
[Hemorrhagic syndrome in newborn infants during a hospital infection with Pseudomonas aeruginosa].
In a department for neonates 21 of the 34 children contracted infections with various clinical manifestations within a relatively short interval (approximately two weeks). Three of the children died and pathoanatomic examination revealed aspects characteristic of vascularitis and diffuse hemorrhage in most organs accompanied by infiltration and oedema. From the lethal cases, part of the sick and healthy children and personnel the same bacterium was isolated--Pseudomonas aeruginosa, suggesting an in-hospital epidemic.
Cross Infection↗
Pulmonary outcome in cystic fibrosis is influenced primarily by mucoid Pseudomonas aeruginosa infection and immune status and only modestly by genotype.
Whether allelic variants of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) independently contribute to pulmonary outcome in CF patients has not been resolved. We used both cross-sectional and mixed-model longitudinal analyses of data from CF patients that were at least 12 years old to determine the influence on pulmonary function (percent predicted forced expiratory volume [FEV(1)]) of the CFTR gene genotype, gender, mucoid Pseudomonas aeruginosa (MPA) infection status, presence of total opsonic antibody to MPA, and, separately, the opsonic antibody activity specific to the mucoid exopolysaccharide (MEP) surface antigen. Two different factors were independently associated with the lack of MPA infection: a high level of MEP-specific opsonic activity (MSOA), implicating an immunologically based mechanism of resistance to infection, and a lack of any type of opsonic antibody to MPA, indicative of no significant exposure or infection. This latter phenotype was found in a subset of CF patients who carried at least one uncommon CFTR gene allele suggestive of a genetic basis for resistance to infection in this group of older CF patients. For CF patients in whom both CFTR gene alleles were identified by screening for the 12 most common variants (75% of alleles), cross-sectional analysis showed that MPA infection was best correlated with lower percent predicted FEV(1), while genotype (two versus one DeltaF508 CFTR gene allele) and a low level of MSOA were associated with increased risk of infection. A mixed-model analysis of longitudinal spirometric measurements that considered multiple risk factors to derive regression equations was used to determine which clinical parameters had the greatest effect on the annual rate of decline in percent predicted FEV(1). This analysis showed that the CFTR gene genotype only modestly modified the constant (y intercept) of the derived equations, while gender and MPA infection status had the largest effects on annual rates of decline in percent predicted FEV(1). These results indicate that the CFTR genotype is usually not a primary determinant of pulmonary function in most CF patients, but gender and MPA infection status are. Infection status is potentially influenced by both immunologic (a high level of MSOA) and genetic factors, such as carriage of a CFTR gene allele that leads to a diagnosis of CF but still confers resistance to infection that is comparable to that of the wild-type CFTR gene.
Adolescent↗
Passive protection against Pseudomonas aeruginosa infection in an experimental leukopenic mouse model.
An experimental leukopenic mouse model was used to evaluate the protective capacities of immunoglobulin G (IgG) fractions directed against toxin A (AT-IgG), elastase (AE-IgG), and lipopolysaccharide (ALPS-IgG) against fatal Pseudomonas aeruginosa infection. Statistically significant protection, as measured by long-term survival, was observed only when mice were treated with serotype-specific ALPS-IgG. The mean lethal dose for P. aeruginosa could be increased by as much as 6,600-fold for mice given ALPS-IgG as compared to mice which received only normal rabbit IgG. ALPS-IgG afforded high levels of protection, even when administered up to 6 h postchallenge. Experiments designed to monitor the growth and spread of a locally administered challenge showed that ALPS-IgG prevented bacteremia and organ colonization, which were pronounced in control animals. The effectiveness of combined antibiotic and immune therapy was tested. Gentamicin alone or in combination with AT-IgG or AE-IgG provided no detectable protection. However, its use with ALPS-IgG afforded substantially higher levels of protection than ALPS-IgG alone.
Animals↗
Use of DNA fingerprinting in decision making for considering closure of neonatal intensive care units because of Pseudomonas aeruginosa bloodstream infections.
BACKGROUND: Bloodstream infections with Pseudomonas aeruginosa have been well-described in neonatal intensive care units (NICU) and have resulted in the temporary closure of some nurseries to new admissions. Nosocomial transmission of these infections has been verified by fingerprint analysis of the isolates. We utilized molecular fingerprinting to identify the source of bloodstream infections in an NICU and used this information to apply infection control measures that allowed the nursery to stay open and continue to accept referrals. METHODS: In June 1998 three premature infants transferred to our hospital (Hospital A) from Hospitals B and C had bloodstream infections with P. aeruginosa. Subsequently one additional neonate transferred from Hospital B was colonized with P. aeruginosa. Random amplification of polymorphic deoxyribonucleic acid (RAPD) was performed on the four isolates. All transfers from Hospital B were cultured, and surveillance programs were instituted in Hospitals A and B. Targeted infection control measures for all transfers were implemented. RESULTS: The four isolates were the same clone by RAPD. Investigation of the environment in Hospital A did not identify any source of the organism. Surveillance cultures on 49 neonates at Hospital A revealed only one patient colonized at an endotracheal tube. This patient was also a transfer from Hospital B. Results from Hospital B identified 4 of 40 (10%) neonates colonized. All isolates were clones identical with the bloodstream isolates from the neonates with bloodstream infections. Infection control measures for all babies transferred from Hospital B resulted in no new cases of P. aeruginosa bacteremia during the next 5 years. CONCLUSIONS: The use of molecular fingerprinting of isolates of P. aeruginosa allowed for a prompt and directed infection control plan to be implemented in Hospitals A and B. It also allowed the NICU in Hospital A to continue to accept referrals from other hospitals and to implement a targeted infection control plan for patients transferred from Hospital B.
Bacteremia↗
Chronic Pseudomonas aeruginosa lung infection in normal and athymic rats.
We have compared a chronic lung infection with Pseudomonas aeruginosa embedded in alginate beads in normal and athymic rats with an acute infection with free live P. aeruginosa bacteria. The following parameters were observed and described: mortality, macroscopic and microscopic pathologic changes, and antibody responses. The rats challenged with P. aeruginosa alginate beads experienced a generally more severe lung pathology and the antibody responses were more homogeneous with less dispersion as compared to the rats having free live P. aeruginosa bacteria. In general, manifestations were more severe in the athymic rats compared to the normal rats. It is, however, notable that the athymic rats developed similar microscopic lung manifestations as the normal rats when given a large number of P. aeruginosa in the beads, with dense accumulation of neutrophil granulocytes and microcolonies comparable to the lesions seen in cystic fibrosis (CF) patients. Early transitory IgM titers were demonstrated in both normal and athymic rats. Whilst athymic rats produced much lower IgG titers than the normal rats, presumably due to the absence of CD4+ cells, higher primary IgA titers were achieved. These two models in normal and athymic rats of the chronic lung infection resembling that seen in CF lungs make it possible to study the influence of the various components of the specific and nonspecific defense systems on the course of the chronic P. aeruginosa lung infection and to evaluate the effect of various immunization schedules and immunomodulatory drugs.
Acute Disease↗
Protective effect of forphenicinol, a low molecular weight immunomodifier, against infection with Pseudomonas aeruginosa in mice and its mechanisms.
The oral administration of forphenicinol increased the survival rate of both normal and immunodepressed mice intraperitoneally or intratracheally infected with clinically isolated strains of Pseudomonas aeruginosa. The therapeutic effect of amikacin on intraperitoneal infection with P. aeruginosa was enhanced by combined use with forphenicinol. Forphenicinol did not enhance the bactericidal activity of polymorphonuclear cells (PMN) towards P. aeruginosa in vitro, but enhanced it in vivo. In vitro study indicated that the macrophages taken from mice treated with forphenicinol or the cultured supernatant of these macrophages enhanced the bactericidal activity of PMN. The protective effect of forphenicinol against P. aeruginosa infection was thus suggested to be due to macrophage activation followed by the enhancement of the bactericidal activity of PMN.
Adjuvants, Immunologic↗
Protamine sulfate reduces the susceptibility of thermally injured mice to Pseudomonas aeruginosa infection.
BACKGROUND: In this study, we investigated the ability of protamine sulfate, at sub-bactericidal dosing, to interfere with the in vivo virulence of Pseudomonas aeruginosa (PAO1) during burn wound infection. MATERIALS AND METHODS: The study was conducted using the murine model of thermal injury. Preliminary experiments determined a protocol for administration of protamine sulfate that had no in vivo bactericidal effects. Based on this, the effect of local injection of protamine sulfate on the in vivo virulence of PAO1 was assessed using these parameters: (1) the percent mortality among PAO1-infected, thermally injured mice; (2) the local proliferation and spread of PAO1 within the infected burned tissue; (3) the systemic spread of PAO1 within thermally injured/infected mice; and (4) the local cytokine response elicited by PAO1 thermally injured/infected mice. RESULTS: Injection of protamine sulfate into the thermally injured tissue of PAO1-infected/thermally injured mice significantly decreased the percent mortality and inhibited the systemic dissemination of PAO1 microorganisms to the liver and spleen. It had no effect, however, on the ability of the bacteria to proliferate and spread within the thermally injured tissue. It also was determined that protamine sulfate was ineffective at preventing mouse death at the dose administered if injected intramuscularly instead of directly into burned tissue. Protamine sulfate reduced the expression of the proinflammatory cytokines IL-6 and LIF in the injured/infected tissue. Heparan sulfate given in conjunction with protamine sulfate returned mortality levels to those of untreated mice. CONCLUSIONS: Our results suggest that: (1) local injection of sub-bactericidal doses of protamine sulfate reduces the virulence of P. aeruginosa; (2) this effect is due to interference with the systemic rather than local spread of P. aeruginosa; and (3) local application of protamine sulfate may have potential as supportive therapy for prevention of systemic P. aeruginosa infection in severely burned patients.
Animals↗
Protective effect of OK-432 on mice against endotoxemia and infection with Pseudomonas aeruginosa and Salmonella enteritidis.
OK-432 has been used clinically as a biological response modifier for cancer therapy. We investigated here the protective effects of OK-432 against endotoxic shock and infectious death caused by Pseudomonas aeruginosa and Salmonella enteritidis in mice and proposed a possible mechanism. Pretreatment of OK-432 reduced the lethality of lipopolysaccharide (LPS)-induced endotoxic shock in D-(+)-galactosamine-sensitized C3H/HeN mice. OK-432 did not affect the TNFalpha production in blood, but it did decrease the susceptibility to TNFalpha. Furthermore, an acceleration of LPS clearance from blood was detected. The pretreatment of OK-432 also decreased the lethality of mice in bacterial infection caused by P. aeruginosa and S. enteritidis. The rapid decrease of the viable bacteria from the circulating blood and in spleen and liver in mice was observed in a manner similar to LPS clearance. These findings indicate that the protective effect of OK-432 against the endotoxemia and bacteremia may depend on an up-regulation of clearance of LPS and bacteria and the augmented resistance to TNFalpha.
Animals↗
Rapid antigen detection assay for identification of Burkholderia (Pseudomonas) pseudomallei infection.
A simple antigen detection test was developed for rapid diagnosis of melioidosis caused by Burkholderia (Pseudomonas) pseudomallei infection. The method was based on the use of a specific monoclonal antibody in a sandwich enzyme-linked immunosorbent assay to capture antigen in clinical specimens culture positive for B. pseudomallei. The results showed the sensitivity and specificity of the test to be 75 and 98%, respectively.
Antibodies, Monoclonal↗
Cross-infection with Pseudomonas aeruginosa in Danish cystic fibrosis patients.
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Cross Infection↗
The effect of rolipram, a type IV phosphodiesterase inhibitor, on Pseudomonas aeruginosa infection of respiratory mucosa.
We have investigated the effect of rolipram, a type IV phosphodiesterase inhibitor, on Pseudomonas aeruginosa infection of the respiratory mucosa of an organ culture model and on the reduction in intracellular cAMP levels seen in human nasal epithelial cells incubated with P. aeruginosa culture filtrate. We have compared rolipram with salmeterol, a long-acting beta-2 agonist, and have also studied the effect of the two agents together. Infected organ cultures had significantly (P < or = .05) increased epithelial damage. Rolipram significantly (P < or = .05) reduced P. aeruginosa-induced epithelial damage and reduced the total number of bacteria adhering to the respiratory mucosa (P < or = .04) in a concentration-dependent manner, although neither rolipram nor salmeterol affected P. aeruginosa growth in broth cultures. Rolipram reduced P. aeruginosa-induced mucosal damage more than salmeterol (P < or = .03). The effect of the two agents was neither additive nor synergistic. Rolipram, salmeterol and both agents together significantly (P < or = .01) increased intracellular cAMP levels in epithelial cells treated with P. aeruginosa culture filtrate. Rolipram alone increased cAMP more than salmeterol or both agents together (P < or = .01), probably because of an interaction between the two agents. These results suggest that agents that elevate intracellular cAMP protect the epithelium during bacterial infection. Rolipram is more effective than salmeterol in preventing P. aeruginosa-induced epithelial damage.
Bacterial Adhesion↗
[Hospital infections with Pseudomonas aeruginosa in a maternity ward].
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Cross Infection↗
Effect of external urinary collection system on colonization and urinary tract infections with Pseudomonas and Klebsiella in men with spinal cord injury.
Urinary tract infection of men with spinal cord injuries has been associated with a high incidence of colonization of the patients with gram-negative bacilli. We have examined the factors influencing colonization of 119 patients with Pseudomonas and Klebsiella and studied methods of reducing this colonization. The urethra, perineum, rectum, and drainage bag of all patients were cultured on selective media at two week intervals until discharge. The use of the external urinary collection system (EUCS) was discontinued in a group of patients at night, in an attempt to reduce colonization. Pseudomonas and Klebsiella were isolated from one or more body sites in 65 percent and 69 percent of total culture days. The urethra, perineum, rectum, and drainage bags were reservoirs of Pseudomonas and Klebsiella in men with spinal cord injuries, even in the absence of urinary tract infections. The EUCS proved to be an important factor influencing colonization. Pseudomonas and Klebsiella colonization was higher in patients using the EUCS. Removal of the EUCS at night reduced urethral colonization with Pseudomonas, but did not significantly reduce urethral colonization with Klebsiella. The prevalence of bacteriuria with Pseudomonas and Klebsiella was not significantly influenced by the use of the EUCS.
Colony Count, Microbial↗
Large outbreak in a surgical intensive care unit of colonization or infection with Pseudomonas aeruginosa that overexpressed an active efflux pump.
During a 30-month survey, 55 patients were colonized or infected by a single clone of Pseudomonas aeruginosa in a surgical intensive care unit (ICU). This clone overexpressed an efflux pump system, and its antibiotic resistance pattern was extremely stable as it spread from patient to patient. Pulsed-field gel electrophoresis showed that isolates from different patients were genetically identical or very similar. We were unable to identify an environmental reservoir, but cultures of hand specimens from 2 health care workers were positive. It was not clear whether this carriage was the source of the epidemic or a consequence of it. However, the propagation of the epidemic clone was probably linked to its transmission by the staff from patient to patient. The outbreak was controlled, with difficulty, by strengthening isolation procedures, replacing the antiseptic soap being used by the staff, and changing the antibiotic prescription policy. This observation emphasizes the importance of compliance with hand washing and universal precautions.
Anti-Bacterial Agents↗
[Current chemotherapy of infections caused by Pseudomonas aeruginosa (author's transl)].
In addition to carbenicillin, the newer beta-lactam antibiotics such as ticarcillin and azlocillin are now available for the chemotherapy of Pseudomonas aeruginosa infections. We investigated the in vitro effect of these antibiotics on 233 isolates from clinical material. We were particularly careful, when choosing the experimental material, to exclude copies of the same individual strain, and we achieved this by combining various epidemiological typing procedures. A comparison of carbenicillin, ticarcillin and azlocillin according to the concentrations at which half of the 233 strains were inhibited showed the ticarcillin values to be higher than those of azlocillin by a factor of 2.1, and carbenicillin values to be higher than those of azlocillin by a factor of 4.9. Individual strains also occurred in which the inhibitory concentration for azlocillin was higher than that of carbenicillin (5 strains) or ticarcillin (11 strains). In 17 out of the 233 isolates no therapeutic success would have been within reach even with the newer beta-lactam antibiotics. The use of ticarcillin and azlocillin permits an extension of the indications for therapy with beta-lactam antibiotics in P. aeruginosa infections, from hitherto 76%, to 90% of the cases. If one includes the aminoglycosides gentamycin, tobramycin, sisomycin and amikacin in the therapeutic armoury, then the proportion of in vitro sensitive strains of P. aeruginosa in the material submitted for examination rises to 98%.
Aminoglycosides↗
Ticarcillin therapy of infections.
Ticarcillin was administered as initial therapy during 73 episodes of infections occurring in 69 adults with neoplastic diseases. During the first six infections, doses of 5 gm were dissolved in 200 ml of solvent and administered intravenously over a 2-h period every 6 h. Four of six infections responded to therapy. However, two of the five Pseudomonas infections failed to respond, whereas the organisms causing the infection were sensitive to ticarcillin in vitro. During the remaining 67 infections, doses of 3.5 g were similarly dissolved and administered intravenously over a 2-h period every 4 h. The overall response to ticarcillin in these 67 infections was 43%. However, 18 of 20 Pseudomonas infections, three Proteus spp. infections, and one infection caused by H. influenzae responded. Only 1 of 7 infections caused by mixed organisms and 5 of 13 infections in which the etiologic agent could not be identified responded. Ticarcillin was ineffective against the majority of Escherichia coli and Klebsiella spp. infections, organisms which were resistant to ticarcillin in vitro. The majority of patients were neutropenic, but the response rate was not dependent on the number of circulating polymorphonuclear neutrophilic leukocytes. Superinfection occurred in seven patients. Erythematous skin rash occurred in two patients, which subsided after discontinuation of the drug. No liver or renal toxicity occurred that could be attributed to ticarcillin.
Adult↗