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Proteus mirabilis fimbriae: construction of an isogenic pmfA mutant and analysis of virulence in a CBA mouse model of ascending urinary tract infection.

Proteus mirabilis, a cause of urinary tract infection and acute pyelonephritis, produces a number of different fimbriae. An isogenic fimbrial mutant of P. mirabilis HI4320 was constructed by marker exchange with delta pmfA::aphA to determine the role of the P. mirabilis fimbriae (PMF) in hemagglutination and in virulence in the CBA mouse model of ascending urinary tract infection. The pmfA mutant, which did not express the 19,500-Da major subunit of PMF, colonized the bladders of transurethrally challenged CBA mice (n = 20 in each group) in numbers 83-fold lower than those of the wild-type strain (mutant, log10 4.87 CFU/g; wild-type strain, log10 6.79 CFU/g; P = 0.023). However, the mutant colonized the kidneys in numbers similar to those of the wild-type strain. Hemagglutination patterns of the mutant ruled out the involvement of PMF in both mannose-resistant, Proteus-like and mannose-resistant, Klebsiella-like hemagglutination. Similarly, PMF does not appear to be involved in adherence to uroepithelial cells (UEC), since the mutant was as adherent as the wild-type strain (mutant, 14.1 +/- 11.7 mean bacteria per UEC, 60% of UEC with > or = 10 bacteria; wild-type strain, 18.1 +/- 16.2 mean bacteria per UEC, 68% of UEC with > or = 10 bacteria; not significantly different). These data suggest a role for PMF in colonization of the bladder but not in colonization of kidney tissue. PMF appear not to be responsible for mannose-resistant, Proteus-like or mannose-resistant, Klebsiella-like hemagglutination.

Animals↗

[Alkaline encrusted cystitis secondary to Proteus mirabilis infection in a HIV infected patient].

We described for the first time an alkaline encrusting cystitis in a patient with the acquired immune deficiency. This is an entity characterized by severe dysuria and long standing urinary frequency, alkaline urine and radiographically visible calcification of the urinary bladder. It has been observed in patients with permanent Foley catheter, persistent infections due to microorganisms with urolytic activity, urinary bilharziosis or tuberculosis, or malignant bladder tumors. None of these entities were described and the patient had all conditions for this syndrome.

Adult↗

[Effectiveness of prodigiozan, methyluracil and levamisole in experimental infection after administration of non-steroidal anti-inflammatory drugs].

The effect of nonsteroid antiinflammatory drugs (NAID) such as voltaren, acetylsalicylic acid, indometacin and naproxen on the efficacy of immunostimulators in treatment of infections caused by Proteus and Staphylococcus was studied. It was shown that except naproxen the NAID were capable of decreasing resistance to Proteus infections. Acetylsalicylic acid increased resistance to staphylococcal infections. The rest of the drugs did not change it. Prodigiozan increased resistance to the infections at the background of the NAID. However, volteran and indometacin lowered its effect in infections caused by Proteus. Levamisol stimulated resistance of mice to the infections at the background of volteran and increased resistance to Proteus infections lowered by acetylsalicylic acid. Methyluracyl was not able to increase resistance to the infections at the background of the NAID. It only increased resistance to Proteus infections lowered by acetylsalicylic acid. Levamisol and methyluracyl did not as a rule increase efficacy of antibiotic therapy at the background of the NAID.

Adjuvants, Immunologic↗

Construction of a urease-negative mutant of Proteus mirabilis: analysis of virulence in a mouse model of ascending urinary tract infection.

Proteus mirabilis, a urease-producing uropathogen, causes serious urinary tract infections in humans. To specifically evaluate the contribution of urease to virulence, a mutation was introduced into P. mirabilis HI4320 by homologous recombination. Virulence was assessed in the CBA mouse model of ascending urinary tract infection. Twenty mice each were challenged transurethrally with P. mirabilis HI4320 and its urease-negative derivative (1 x 10(9) to 2 x 10(9) CFU). At 48 h animals were sacrificed and the mean log10 CFU per milliliter of urine (parent, 6.23; mutant, 4.19; P = 0.0014) or per gram of bladder (parent, 6.29; mutant, 4.28; P = 0.0002), left kidney (parent, 4.11; mutant, 1.02; P = 0.00009), and right kidney (parent, 4.11; mutant, 2.43; P = 0.036) were all shown to be significantly different. These data demonstrate a role for urease as a critical virulence determinant for uropathogenic P. mirabilis.

Animals↗

Ultrastructure of Proteus mirabilis swarmer cell rafts and role of swarming in catheter-associated urinary tract infection.

Proteus mirabilis is a common cause of catheter-associated urinary tract infection (C-UTI). It blocks indwelling urethral catheters through the formation of extensive crystalline biofilms. The obstruction of urine flow can induce episodes of pyelonephritis, septicemia, and shock. P. mirabilis exhibits a type of motility referred to as swarming, in which multicellular rafts of elongated, hyperflagellated swarmer cells form and move rapidly in concert over solid surfaces. It has been suggested that swarming is important in the pathogenesis of C-UTI. In this study we generated a set of stable transposon mutants deficient in swarming and used them to assess the role of swarming in the migration of P. mirabilis over urinary catheters. Swarming was found to be essential for migration over all-silicone catheters. Swarming-deficient mutants were attenuated in migration over hydrogel-coated latex catheters, but those capable of swimming motility were able to move over and infect these surfaces. A novel vapor fixation technique for the preparation of specimens and scanning electron microscopy were used to resolve the ultrastructure of P. mirabilis multicellular rafts. The flagellar filaments of P. mirabilis were found to be highly organized during raft migration and were interwoven in phase to form helical connections between adjacent swarmer cells. Mutants lacking these novel organized structures failed to swarm successfully. We suggest that these structures are important for migration and formation of multicellular rafts. In addition, the highly organized structure of multicellular rafts enables P. mirabilis to initiate C-UTI by migration over catheter surfaces from the urethral meatus into the bladder.

DNA Transposable Elements↗

Ammonia encephalopathy secondary to urinary tract infection with Proteus mirabilis.

Hyperammonemia with coma, tachypnea, and respiratory alkalosis developed in a 3-year-old boy with prune"-belly syndrome during a urinary tract infection with Proteus mirabilis. Hyperammonemia is thought to have resulted from the production within the massively dilated urinary tract of excessive amounts of ammonia due to bacterial urease, and its subsequent reabsorption into the systemic circulation. The patient rapidly improved following parenteral antibiotic therapy and continuous catheter drainage of the urinary tract.

Abdominal Muscles↗

Molecular epidemiology of Proteus mirabilis infections of the catheterized urinary tract.

Proteus mirabilis compromises the care of many patients undergoing long-term indwelling bladder catheterization. It forms crystalline bacterial biofilms in catheters which block the flow of urine, causing either incontinence due to leakage or painful distention of the bladder due to urinary retention. If it is not dealt with, catheter blockage can lead to pyelonephritis and septicemia. We have examined the epidemiology of catheter-associated P. mirabilis infections by use of pulsed-field gel electrophoresis (PFGE) of NotI restriction enzyme digests of bacterial DNA. This technique was shown to be more discriminatory than the classical phenotypic Dienes typing technique. We demonstrated that each of 42 isolates from diverse environmental sources and 10 of 12 isolates from blood, wound swabs, and mid-stream urine samples of hospitalized patients had distinct genotypes. Examination of a set of 55 isolates of P. mirabilis, each from a different clinical or environmental source, identified 49 distinct genotypes and 43 Dienes types. The index of discrimination was 0.993 for the PFGE method and 0.988 for the Dienes method. Applying the PFGE method to isolates from catheter-associated urinary tract infections confirmed that the strains present in the crystalline catheter biofilms were identical to those isolated from the same patient's urine. An analysis of samples taken during a prospective study of infections in catheterized nursing home patients revealed that a single genotype of P. mirabilis can persist in the urinary tract despite many changes of catheter, periods of noncatheterization, and antibiotic therapy.

Biofilms↗

Monoclonal antibody-mediated protection and neutralization of motility in experimental Proteus mirabilis infection.

A panel of monoclonal antibodies with specificity for a wound isolate of Proteus mirabilis was established. Of nine antibodies studied in detail, three were broadly reactive with various Proteus isolates, while six reacted in a serotype-specific fashion with the strain used for immunization. Five of the six serotype-specific antibodies were reactive with lipopolysaccharide. The sixth serotype-specific antibody, 4-F (immunoglobulin G1 [IgG1]), was potently protective in a burn wound sepsis model and recognized a protein antigen. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot (immunoblot) analysis were used to determine that 4-F was reactive with flagellar protein. Approximately 1.3 micrograms of the antibody was sufficient to provide protection against 8 50% lethal doses of wound isolate, and approximately 26 micrograms provided full protection against challenge with 333 50% lethal doses. In vitro test results indicated that 4-F inhibited the motility of the wound isolate, and in vivo testing showed that it inhibited dissemination of the inoculum from the burn site to the liver and spleen. Whereas the antibody was highly effective in preventing the death of mice subsequent to challenge at a burn site, no protection was seen following an intraperitoneal challenge. These results may therefore indicate that the protection observed in the burn model is solely a reflection of the capacity of 4-F to neutralize bacterial motility.

Animals↗

Visualization of Proteus mirabilis morphotypes in the urinary tract: the elongated swarmer cell is rarely observed in ascending urinary tract infection.

Proteus mirabilis, a common cause of nosocomial and catheter-associated urinary tract infection, colonizes the bladder and ascends the ureters to the proximal tubules of the kidneys, leading to the development of acute pyelonephritis. P. mirabilis is capable of swarming, a form of multicellular behavior in which bacteria differentiate from the short rod typical of members of the family Enterobacteriaceae, termed the swimmer cell, into hyperflagellated elongated bacteria capable of rapid and coordinated population migration across surfaces, called the swarmer cell. There has been considerable debate as to which morphotype predominates during urinary tract infection. P. mirabilis(pBAC001), which expresses green fluorescent protein in both swimming and swarming morphotypes, was constructed to quantify the prevalence of each morphotype in ascending urinary tract infection. Transurethral inoculation of P. mirabilis(pBAC001) resulted in ascending urinary tract infection and kidney pathology in mice examined at both 2 and 4 days postinoculation. Using confocal microscopy, we were able to investigate the morphotypes of the bacteria in the urinary tract. Of 5,087 bacteria measured in bladders, ureters, and kidneys, only 7 (0.14%) were identified as swarmers. MR/P fimbria expression, which correlates with the swimmer phenotype, is prevalent on bacteria in the ureters and bladder. We conclude that, by far, the predominant morphotype present in the urinary tract during ascending infection is the short rod-the swimmer cell.

Animals↗

Comparative activities of cefotiam and cefazolin against urinary tract infections with Proteus mirabilis in mice.

The therapeutic effect of cefotiam on experimental urinary tract infections with Proteus mirabilis IFO 3849 in mice was compared with that of cefazolin. The minimal inhibitory concentrations of cefotiam and cefazolin against the test organism were 1.56 and 25 micrograms/ml, respectively. Beginning 3 days after infection, various doses of each cephalosporin were given subcutaneously twice a day for 5 days. Doses of 100 mg of cefotiam per kg or more sterilized the urine within 3 days and effected a marked reduction or complete eradication of bacteria in the bladder walls and kidneys of mice sacrificed the day after treatment was terminated. A dose of cefazolin greater than 800 mg/kg was required for equivalent therapeutic results. Clearance of bacteria from urinary tract organs was as rapid or more rapid with 50-mg/kg doses of cefotiam as with 200-mg/kg doses of cefazolin. Much more rapid clearance was attained with 200-mg/kg doses of cefotiam. The concentrations of cefotiam attained in plasma, kidney, and urine were lower than the cefazolin levels achieved at an equivalent dose. The superiority of cefotiam over cefazolin in treatment of experimental urinary tract infections appears to be due to its greater activity against the test organism.

Animals↗

Contribution of Proteus mirabilis urease to persistence, urolithiasis, and acute pyelonephritis in a mouse model of ascending urinary tract infection.

Proteus mirabilis, a significant cause of bacteriuria and acute pyelonephritis in humans, produces urease. This high-molecular-weight, multimeric, cytoplasmic enzyme hydrolyzes urea to ammonia and carbon dioxide. To assess the role of urease in colonization, urolithiasis, and acute pyelonephritis in an animal model of ascending urinary tract infection, we compared a uropathogenic strain of P. mirabilis with its isogenic urease-negative mutant, containing an insertion mutation within ureC, the gene encoding the large subunit of the enzyme. Mice challenged transurethrally with the parent strain developed significant bacteriuria and urinary stones. The urease-negative mutant had a 50% infective dose of 2.7 x 10(9) CFU, a value more than 1,000-fold greater than that of the parent strain (2.2 x 10(6) CFU). The urease-positive parent strain reached significantly higher concentrations and persisted significantly longer in the bladder and kidney than did the mutant. Indeed, in the kidney, the parent strain increased in concentration while the mutant concentration fell so that, by 1 week, the parent strain concentration was 10(6) times that of the mutant. Similarly, the urease-positive parent produced significantly more severe renal pathology than the mutant. The initial abnormalities were in and around the pelvis and consisted of acute inflammation and epithelial necrosis. By 1 week, pyelitis was more severe, crystals were seen in the pelvis, and acute pyelonephritis, with acute interstitial inflammation, tubular epithelial cell necrosis, and in some cases abscesses, had developed. By 2 weeks, more animals had renal abscesses and radial bands of fibrosis. We conclude that the urease of P. mirabilis is a critical virulence determinant for colonization, urolithiasis, and severe acute pyelonephritis.

Acute Disease↗