Colistin treatment of experimentally produced Pseudomonas corneal infection.
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Survival for more than 5 y was obtained with home-based parenteral antibiotic therapy in a 68-y-old male with Pseudomonas aeruginosa infection of an aortic-bifemoral prosthetic graft. Surgical intervention was deemed to carry to high a risk and we suggest that lifelong suppressive antibiotic therapy may be an option in selected patients.
Distribution of Pseudomonas aeruginosa was observed, both in cancerous hospitalized and ambulatorial patients, through Uroculture or by Screening at the time of admission in Hospital. The data have been statistically evaluated according to the specific sectorial activities. The chemiosensitivity of isolated strains was evaluated for eight antibiotics, selected among the most active ones. Minimal Inhibent Concentration (MIC) and Minimal Bactericidal Concentration (MBC) were also evaluated for Gentamicin and Colistin. The results obtained are relevant to the significance of Pseudomonas aeruginosa infection in neoplastic diseases.
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PURPOSE: To describe a Pseudomonas aeruginosa corneal infection resulting from orthokeratology. METHODS: Case report. RESULTS: A 17-year-old boy wearing orthokeratology (OK) lenses was referred to our clinic because of redness in his right eye in spite of his usage of ofloxacin (OFLX) eye drops. An excavated paracentral corneal ulcer with an immune ring and hypopyon was observed. It was positioned under the paracentral steeper portion of the optic of the OK lens. Culture of the lens solution revealed P. aeruginosa. The patient was treated with topical OFLX and cefmenoxime (CMX) plus intravenous and subconjunctival injections of cefozopran (CZOP), successfully. The antibiotic susceptibility of P. aeruginosa by the disk diffusion susceptibility test was reduced under moderately hypoxic conditions. Glycocalyx slime was formed on the OK lens in vitro by P. aeruginosa isolated from the case. CONCLUSIONS: Changes in P. aeruginosa susceptibility to antibiotics under moderately hypoxic conditions and glycocalyx slime formation might affect the features of OK lens-associated infections.
Chronic bronchopulmonary Pseudomonas aeruginosa infection, initiated by intratracheal instillation of 1 to 2 x 10(5) colony-forming units of a mucoid strain of bacteria trapped in agar beads, was characterized in resistant BALB/c mice and susceptible C57BL/6 (B6) mice through 28 d postinfection. B6 mice experienced a more severe infection than BALB/c mice as evidenced by significantly higher mortality and significantly greater weight loss during the first 14 d. Furthermore, B6 mice had significantly higher numbers of bacteria in the lungs through 21 d after infection. Overall, only 22% of these hosts cleared the infection. In contrast, 67% of BALB/c mice cleared the infection. These differences between resistant and susceptible mice were found to correlate with histopathologic differences in the type of inflammation and the extent of tissue damage. An acute, predominantly neutrophilic inflammation and extensive tissue damage were apparent in the lungs of susceptible B6 mice, whereas chronic, granulomatous inflammation and little or no tissue damage were visible in resistant BALB/c mice. The finding of acute inflammation in the lungs of infected B6 mice was confirmed by fluorescence-activated cell sorter (FACS) analyses, which demonstrated that these mice had significantly greater proportions of polymorphonuclear neutrophils in the lungs on Days 7 and 14 after infection than did BALB/c mice. FACS analyses also revealed significant and similar increases in CD3(+) lung cells in both strains as the infection progressed. The CD4/CD8 ratio was significantly greater in BALB/c mice by 21 d after infection when the majority of these animals, but not B6 mice, had cleared the infection.
A new semi-synthetic penicillin, sulbenicillin, was evaluated with regard to clinical effect on infections caused by Pseudomonas aeruginosa and other bacteria, serum concentrations obtained after intravenous administration and antibacterial spectrum, in comparison with the closely related antibiotic carbenicillin. The antibacterial spectra of sulbenicillin and carbenicillin were similar but the MIC values were lower for sulbenicillin against most of the bacterial strains tested. The serum concentrations obtained after administration of 5 g sulbenicillin were significantly higher than those obtained after 5 g carbenicillin although no significant differences in serum half-lives were observed. The clinical effect of sulbenicillin--alone or alternating with carbenicillin--on pseudomonas infections with varying localisation was found to be good in 11 and fair in 3 of 16 treated patients. Two treatment failures were cases of chronic wound infection. In addition to the pseudomonas infections, 9 of the patients also had concurrent infections with other bacteria, e.g. pencillinase-producing staphylococci and Klebsiella, and in all these cases bacterial growth was eliminated during therapy. No serious side effects were observed during sulbenicillin treatment but some of the patients developed massive growth of fungi in the urine, which disappeared after the treatment was stopped.
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The clinical and microbiologic characteristics of 55 cases of Pseudomonas putida infection in 53 patients in a medical center in Taiwan from April 1988 to March 1993 are reported. P. putida was cultured in the decreasing order of frequency from urine (24 isolates), sputum (12), blood (10), wound discharge (3), peritoneal fluid (3), cerebrospinal fluid (2) and umbilical swab (1). Of the adult patients, 23% (12/53) were considered to be contaminated or colonized with P. putida. Of the 41 patients with manifest disease. 17 (41%) had urinary tract infections, 10 (24%) had pneumonia, 8 (19%) had septicemia, 3 (7%) had wound infections, 2 (5%) had meningitis and 1 (2%) had peritonitis. Of these, 55% were nosocomial infections. The case fatality rate was 29% (12/41). There was no significant correlation between patient mortality and the type of disease caused by the bacterium. Results of in vitro susceptibility tests suggested that imipenem and ceftazidime were more effective than other antimicrobials. This study indicates that the clinical spectrum of diseases caused by P. putida is broader and the incidence of true infection is higher than previously expected, especially among hospitalized patients who undergo invasive procedures such as placement of intravascular devices, urinary catheterization and intubation.
The prevalence of Pseudomonas cepacia infection increased from 10% in 1971 to 18% by 1981 in a population of approximately 500 patients with cystic fibrosis. Carriage of P. aeruginosa has remained unchanged at 70% to 80% over the same period. Patients infected with P. cepacia have greater impairment of pulmonary function than those with P. aeruginosa. A syndrome characterized by high fever, severe progressive respiratory failure, leukocytosis, and elevated erythrocyte sedimentation rate has occurred in eight patients over the past 3 years, with a 62% fatality rate. Because P. cepacia strains are uniformly resistant to ticarcillin, piperacillin, and aminoglycosides, and because ceftazidime is ineffective despite in vitro activity, treatment of these infections is very difficult. Prevention of acquisition and effective treatment of P. cepacia in patients with cystic fibrosis are now major clinical problems in our clinic.
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OBJECTIVES: (1) To determine the incidence and outcome of Pseudomonas aeruginosa infection in HIV-infected patients. (2) To study the antimicrobial susceptibility of P. aeruginosa isolates in this particular population. (3) To identify risk factors for these infections. PATIENTS AND METHODS: A retrospective case-control study performed in a 28-bed infectious-diseases unit in a 940-bed university hospital. All cases were defined as HIV-infected patients with severe infections due to P. aeruginosa, including bacteremia, lower or upper respiratory tract infections, infections related to a central venous catheter, and cutaneous/muscular infection. Each case was matched with an HIV-seropositive control not infected by P. aeruginosa and hospitalized on the same dates as the cases. RESULTS: One thousand and thirty-five HIV-infected patients were hospitalized during the study period. A first severe P. aeruginosa infection was documented in 41 patients, giving an overall annual incidence note of 2.51 episodes per 100 admissions. Forty of the 41 case notes were available for analysis. They consisted of 17 cases of bacteraemia, four upper respiratory tract infections, 10 lower respiratory tract infections, three catheter-related infections, and six cutaneous/muscular infections. Of these 40 cases, 60% were nosocomial and the remainder were community-acquired. The overall mortality rate was 22% (47% in bacteraemic forms). Twenty five percent of patients relapsed after an average of 37 days. The case-control comparison showed that AIDS was more frequent among the cases (92% vs. 74%, P = 0.04), who also had a lower PN count (P = 0.005), and a lower CD4 cell count (15.7 +/- 18.8/mm3 vs. 118 +/- 211/mm3; P = 0.0007). The number of days spent in hospital in the previous 3 months (29.3 +/- 20.7 vs. 19.7 +/- 14, P = 0.04) was significantly higher among the cases. In a multivariate analysis, examining treatments received in the previous month, only co-trimoxazole [OR = 5.5 (1.1-26.9)], penicillins [OR = 5.2 (1.1-25.3)], steroids [OR = 5.5, (1.2-25.5)] and a CD4 cell count below 50/mm3 [OR = 13.2 (1.4-129.4)] were identified as risk factors. CONCLUSION: P. aeruginosa infection is a not frequent bacterial disease in highly immunodeficient HIV-infected patients. It is frequently fatal and must be borne in mind in the advanced stages of HIV disease, especially when patients have received co-trimoxazole (trianthoprim-sulphamethoxazole), penicillins or steroids.
BACKGROUND: Pseudomonas aeruginosa strains are generally resistant to many antibiotics, and nosocomial infections because of this species are one of the major problems in many hospitals. Molecular typing provides very useful information about origin and transmission of the strains. The aims of the present study were to investigate clinical and microbiologic characteristics of the nosocomial infections caused by P aeruginosa strains in a medical center and to bring up the cross-transmission level of this opportunistic pathogen in a university hospital by analyzing the clonal relationship among the isolates. METHODS: A total of 105 P aeruginosa strains had been identified among the 80 inpatients in a 1-year period from August 2003 to August 2004. Demographic, clinical, and epidemiologic data of the patients were prospectively recorded. The standardized disk-diffusion method was used to determine resistance of the strains to imipenem, ceftazidime, aztreonam, amikacin, gentamicin, mezlocillin, cefepime, tobramycin, meropenem, ceftriaxone, and ciprofloxacin. Clonal relatedness of the strains was investigated by pulsed-field gel electrophoresis (PFGE). RESULTS: Of the 105 P aeruginosa strains identified, 45 (43%) were isolated from the patients hospitalized in intensive care units. Thirteen patients had repeated pseudomonas infection (total 38 infections/13 patients); 26 of these repeated infections in 9 patients showed the same localization. Half of the patients had at least 1 underlying disease such as burn (48%), chronic illness (32%), and malignancy (20%). Fifty-seven patients (71%) had urinary and/or other catheterization. Urinary tract infection (35%) was the most frequent infection encountered, followed by respiratory tract infection (34%) and sepsis (13%). Resistance to the antibiotics tested was in the 12% to 88% range; amikacin was the most effective and ceftriaxone was the least effective antibiotic. The PFGE typing method showed that 28 of the 80 patients' isolates were clonally related, including 23 indistinguishable or closely related strains (29%), and 5 possibly related strains (6%). Epidemiologic data of the 16 patients (20% of the patients) confirmed a clonal relationship among the strains. Of the 26 isolates of the 9 patients having repeated infection in the same location, 18 (69%) were in the clonally related groups, whereas 11 of the 12 strains isolated from repeated infections on different body sites were clonally different. CONCLUSION: Our results indicated that P aeruginosa infections in our hospital mainly affected the patients hospitalized in intensive care units and those having catheterization, burn, and/or chronic illness. Amikacin was the best antibiotic as far as bacterial resistance was considered. Although lack of major PFGE type confirmed no P aeruginosa outbreak, typing results showed that cross transmission and treatment failure are the 2 main problems, which should be consider together to prevent this bacterial infection in medical centers.
Two cases of Pseudomonas aeruginosa infection, with hemograms and marrow aspirates simulating acute promyelocytic leukemia, are presented. The absence of either Auer rods or abnormal granulation, as well as the clinical history of infection, are important clues to the benign nature of the process. Experimental and clinical evidence to support the role of Pseudomonas endotoxin in myeloid suppression and maturation arrest is reviewed.
Risk factors for multi-drug resistant Pseudomonas aeruginosa (MDRP) infections were investigated using a case-control study design involving MDRP patients (N = 44) and controls (N = 68). A retrospective cohort study was performed to study the predictive factors of clinical outcome in MDRP patients. Multivariate analysis demonstrated that previous exposure to imipenem/meropenem [odds ratio (OR), 44.8] and mechanical ventilation (OR 8.2) were risk factors for nosocomial infections of MDRP. Of 44 cases of MDRP infections, 20 patients died directly from P. aeruginosa infections. Pulsed-field gel electrophoresis (PFGE) analysis on serial isolates from three patients showed that profiles of isolates from the same patient were closely related or indistinguishable. Multivariate analysis demonstrated that patients with adverse clinical outcomes were more likely to have been treated with mechanical ventilation (OR 12.8), and more likely to have MDRP resistance patterns that did not change during treatments (OR 26.5). We concluded that mechanical ventilation and previous exposure to imipenem/meropenem were independent risk factors for MDRP infections, while mechanical ventilation and antibiotic resistance switch were predictive factors of outcomes of MDRP infections.
Pseudomonas aeruginosa remains a cause of serious wound infection and mortality in burn patients. By means of restriction fragment length polymorphism analysis and a DNA probe for the pilin gene of Pseudomonas, a lethal strain of nosocomial P. aeruginosa was identified as the cause of an outbreak of wound infections among burn patients. Environmental surveys suggested an association of the outbreak with hydrotherapy provided to many patients in a common facility. In a trial of burn wound care without hydrotherapy, overall mortality was reduced significantly, mortality associated with pseudomonas sepsis was eliminated, and the strain of P. aeruginosa associated with earlier mortality was eradicated. Moreover, fewer nosocomial pseudomonas infections, lower levels of pseudomonas resistance to aminoglycoside antibiotics, significantly fewer pseudomonas infections of skin graft donor sites, and later appearance of Pseodomonas species in burn patients were found during the period when hydrotherapy was not used.
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Development of an effective vaccine against the multiple presentations of Pseudomonas aeruginosa infection, including nosocomial pneumonia, bloodstream infections, chronic lung infections in cystic fibrosis patients and potentially sight-threatening keratitis in users of contact lenses, is a high priority. As with vaccine development for any pathogen, key information about the most effective immunologic effectors of immunity and target antigens needs to be established. For P. aeruginosa, although there is a role for cell-mediated immunity in animals following active vaccination, the bulk of the data indicate that opsonically-active antibodies provide the most effective mediators of acquired immunity. Major target antigens include the lipopolysaccharide O-polysaccharides, cell-surface alginate, flagella, components of the Type III secretion apparatus and outer membrane proteins with a potentially additive effect achieved by including immune effectors to toxins and proteases. A variety of active vaccination approaches have the potential for efficacy such as vaccination with purified or recombinant antigens incorporating multiple epitopes, conjugate vaccines incorporating proteins and carbohydrate antigens, and live attenuated vaccines, including heterologous antigen delivery systems expressing immunogenic P. aeruginosa antigens. A diverse range of passive immunotherapeutic approaches are also candidates for effective immunity, with a variety of human monoclonal antibodies described over the years with good preclinical efficacy and some early Phase I and II studies in humans. Finding an effective active and/or passive vaccination strategy for P. aeruginosa infections could be realized in the next 5 to 10 years, but will require that advances are made in the understanding of antigen expression and immune effectors that work in different human tissues and clinical settings, and also require a means to validate that clinical outcomes achieved in Phase III trials represent meaningful advances in management and treatment of P. aeruginosa infections.