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PubMed1991

Proteus mirabilis flagella and MR/P fimbriae: isolation, purification, N-terminal analysis, and serum antibody response following experimental urinary tract infection.

Urinary tract infection with Proteus mirabilis may lead to serious complications, including cystitis, acute pyelonephritis, fever, bacteremia, and death. In addition to the production of hemolysin and the enzyme urease, fimbriae and flagellum-mediated motility have been postulated as virulence factors for this species. We purified mannose-resistant/proteuslike (MR/P) fimbriae and flagella from strains CFT322 and HU2450, respectively. Electron microscopy revealed highly concentrated preparations of fimbriae and flagella. Fimbrial and flagellar structural subunits were estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 18.5 and 41 kDa, respectively. N-terminal sequencing revealed that 10 of the first 20 amino acids of the major MR/P subunit matched the sequence of the P. mirabilis uroepithelial cell adhesin N terminus and 11 of 20 amino acids matched the predicted amino acid sequence of the Escherichia coli P fimbriae structural subunit, PapA. In addition, 90 and 80% homologies were found between the first 20 amino acids of P. mirabilis flagellin and those of Salmonella typhimurium phase-1 flagellin and the E. coli hag gene product, respectively. An enzyme-linked immunosorbent assay using purified antigens showed a strong reaction between the MR/P fimbriae or flagella and sera of CBA mice challenged transurethrally with P. mirabilis. A possible role for MR/P fimbriae in the pathogenesis of urinary tract infection is supported by (i) a strong immune response to the antigen in experimentally infected animals, (ii) amino acid sequence similarity to other enteric surface structure, and (iii) our previously reported observation that MR/P fimbriae are expressed preferentially as the sole fimbrial type in human pyelonephritis isolates.

Amino Acid Sequence↗
PubMed1992

Ability of Proteus mirabilis to invade human urothelial cells is coupled to motility and swarming differentiation.

Proteus mirabilis causes serious kidney infections which can involve invasion of host urothelial cells. We present data showing that the ability to invade host urothelial cells is closely coupled to swarming, a form of cyclical multicellular behavior in which vegetative bacteria differentiate into hyperflagellated, filamentous swarm cells capable of coordinated and rapid population migration. Entry into the human urothelial cell line EJ/28 by P. mirabilis U6450 isolated at different stages throughout the swarming cycle was measured by the antibiotic protection assay method and confirmed by electron microscopy. Differentiated filaments entered urothelial cells within 30 min and were 15-fold more invasive (ca. 0.18% entry in 2 h) than an equivalent dry weight of vegetative cells isolated before differentiation, which attained only ca. 0.012% entry in the 2-h assay. The invasive ability of P. mirabilis was modulated in parallel with flagellin levels throughout two cycles of swarming. Septation and division of intracellular swarm cells produced between 50 and 300 vegetative bacteria per human cell, compared with 4 to 12 intracellular bacteria after incubation with vegetative cells. Transposon (Tn5) mutants of P. mirabilis with specific defects in motility and multicellular behavior were compared with the wild-type for the ability to invade. Mutants which lacked flagella (nonmotile nonswarming) were entirely noninvasive, and those which were motile but defective in swarm cell formation (motile nonswarming) were 25-fold less invasive than wild-type vegetative cells. Mutants with defects in the coordination of multicellular migration and the temporal control of consolidation (cyclical reversion of swarm cells to vegetative cells) were reduced ca. 3- to 12-fold in the ability to enter urothelial cells. In contrast, a nonhemolytic transposon mutant which swarmed normally retained over 80% of wild-type invasive ability. Swarm cells and early consolidation cells were at least 10-fold more cytolytic than vegetative cells as a result of their high-level production of hemolysin.

Animals↗
PubMed1994

Internalization of Proteus mirabilis by human renal epithelial cells.

Proteus mirabilis, a common agent of bacteriuria in humans, causes acute pyelonephritis and bacteremia. Renal epithelium provides a barrier between luminal organisms and the renal interstitium. We have hypothesized that P. mirabilis may be internalized into renal epithelium. To test this hypothesis, we added suspensions of three P. mirabilis strains (10(8) CFU) to confluent monolayers of primary cultures of human renal proximal tubular epithelial cells (HRPTEC) and, after 3 h, found the bacteria internalized within membrane-bound vacuoles by light and electron microscopy. Internalization of bacteria by HRPTEC was corroborated by using the gentamicin protection assay. Cytolysis of HRPTEC by the HpmA hemolysin, however, was a confounding factor in this assay, and therefore a hemolysin-negative hpmA mutant was used in subsequent experiments. The nonhemolytic mutant WPM111 did not disrupt the monolayer and was recovered in numbers that were 10- to 100-fold higher than those of the hemolytic parent BA6163. Cytochalasin D (20 micrograms/ml) inhibited internalization of Salmonella typhimurium but not that of P. mirabilis, suggesting that the latter species enters HRPTEC by a mechanism that is not dependent on actin polymerization. We suggest that HpmA hemolysin-mediated cytotoxicity and internalization of bacteria by HRPTEC may play a role in the development of Proteus pyelonephritis.

Cells, Cultured↗
PubMed1999

Requirement of MrpH for mannose-resistant Proteus-like fimbria-mediated hemagglutination by Proteus mirabilis.

Two new genes, mrpH and mrpJ, were identified downstream of mrpG in the mrp gene cluster encoding mannose-resistant Proteus-like (MR/P) fimbriae of uropathogenic Proteus mirabilis. Since the predicted MrpH has 30% amino acid sequence identity to PapG, the Galalpha(1-4)Gal-binding adhesin of Escherichia coli P fimbriae, we hypothesized that mrpH encodes the functional MR/P hemagglutinin. MR/P fimbriae, expressed in E. coli DH5alpha, conferred on bacteria both the ability to cause mannose-resistant hemagglutination and the ability to aggregate to form pellicles on the broth surface. Both a DeltamrpH mutant expressed in E. coli DH5alpha and an isogenic mrpH::aphA mutant of P. mirabilis were unable to produce normal MR/P fimbriae efficiently, suggesting that MrpH was involved in fimbrial assembly. Amino acid residue substitution of the N-terminal cysteine residues (C66S and C128S) of MrpH abolished the receptor-binding activity (hemagglutinating ability) of MrpH but allowed normal fimbrial assembly, supporting the notion that MrpH was the functional MR/P hemagglutinin. Immunogold electron microscopy of P. mirabilis HI4320 revealed that MrpH was located at the tip of MR/P fimbriae, also consistent with its role in receptor binding. The isogenic mrpH::aphA mutant of HI4320 was less able to colonize the urine, bladder, and kidneys in a mouse model of ascending urinary tract infection (P < 0.01), and therefore MR/P fimbriae contribute significantly to bacterial colonization in mice. While there are similarities between P. mirabilis MR/P and E. coli P fimbriae, there are more notable differences: (i) synthesis of the MrpH adhesin is required to initiate fimbrial assembly, (ii) MR/P fimbriae confer an aggregation phenotype, (iii) site-directed mutation of specific residues can abolish receptor binding but allows fimbrial assembly, and (iv) mutation of the adhesin gene abolishes virulence in a mouse model of ascending urinary tract infection.

Adhesins, Bacterial↗
PubMed2002

Visualization of Proteus mirabilis within the matrix of urease-induced bladder stones during experimental urinary tract infection.

The virulence of a urease-negative mutant of uropathogenic Proteus mirabilis and its wild-type parent strain was assessed by using a CBA mouse model of catheterized urinary tract infection. Overall, catheterized mice were significantly more susceptible than uncatheterized mice to infection by wild-type P. mirabilis. At a high inoculum, the urease-negative mutant successfully colonized bladders of catheterized mice but did not cause urolithiasis and was still severely attenuated in its ability to ascend to kidneys. Using confocal laser scanning microscopy and scanning electron microscopy, we demonstrated the presence of P. mirabilis within the urease-induced stone matrix. Alizarin red S staining was used to detect calcium-containing deposits in bladder and kidney tissues of P. mirabilis-infected mice.

Animals↗
PubMed2003

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↗
PubMed2004

Development of an intranasal vaccine to prevent urinary tract infection by Proteus mirabilis.

Proteus mirabilis commonly infects the complicated urinary tract and is associated with urolithiasis. Stone formation is caused by bacterial urease, which hydrolyzes urea to ammonia, causing local pH to rise, and leads to the subsequent precipitation of magnesium ammonium phosphate (struvite) and calcium phosphate (apatite) crystals. To prevent these infections, we vaccinated CBA mice with formalin-killed bacteria or purified mannose-resistant, Proteus-like (MR/P) fimbriae, a surface antigen expressed by P. mirabilis during experimental urinary tract infection, via four routes of immunization: subcutaneous, intranasal, transurethral, and oral. We assessed the efficacy of vaccination using the CBA mouse model of ascending urinary tract infection. Subcutaneous or intranasal immunization with formalin-killed bacteria and intranasal or transurethral immunization with purified MR/P fimbriae significantly protected CBA mice from ascending urinary tract infection by P. mirabilis (P < 0.05). To investigate the potential of MrpH, the MR/P fimbrial tip adhesin, as a vaccine, the mature MrpH peptide (residues 23 to 275, excluding the signal peptide), and the N-terminal receptor-binding domain of MrpH (residues 23 to 157) were overexpressed as C-terminal fusions to maltose-binding protein (MBP) and purified on amylose resins. Intranasal immunization of CBA mice with MBP-MrpH (residues 23 to 157) conferred effective protection against urinary tract infection by P. mirabilis (P < 0.002).

Adhesins, Bacterial↗
PubMed1976

Evidence against the involvement of chemotaxis in swarming of Proteus mirabilis.

Nonswarming and nonchemotactic mutants of Proteus mirabilis were isolated after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine or ultraviolet light. These mutants were used in experiments to determine if chemotaxis is involved in the swarming of P. mirabilis. Nonchemotactic mutants failed to form chemotactic bands in a semisolid casein hydrolysate medium, yet they swarmed on the same medium containing 1.5% agar. Nonswarming mutants were attracted towards individual amino acids and components of tryptose. In cross-feeding experiments, no evidence was obtained to indicate the production of a diffusable chemical repellent. In studies with the wild-type P. mirabilis, no clear-cut negative chemotaxis was seen even though three different assays were used and numerous chemicals were tested. Additional evidence against the involvement of chemotaxis in swarming comes from finding that dialysis does not interfere with swarming; swarm cells will swarm immediately when transferred to fresh media, and swarm cells will swarm on an agar-water medium supplemented with a surfactant. These data indicate that chemotaxis is not involved in the swarming of P. mirabilis.

Amino Acids↗
PubMed1978

Structure, function, and regulation of Escherichia coli rRNA in Proteus mirabilis.

Escherichia coli rRNA genes have been introduced into Proteus mirabilis on an F-prime factor (F'14). A portion of the ribosomes in the resulting merodiploid consist of E. coli rRNA and P. mirabilis ribosomal proteins. These ribosomes are structurally similar to normal P. mirabilis or E. coli ribosomes and exhibit many or all of the functional properties of normal ribosomes. The accumulation of E. coli rRNA in the merodiploid is regulated in a way similar to the the regulation of P. mirabilis rRNA.

Bacterial Proteins↗
PubMed1991

Evidence for N----O acetyl migration as the mechanism for O acetylation of peptidoglycan in Proteus mirabilis.

O-acetylated peptidoglycan was purified from Proteus mirabilis grown in the presence of specifically radiolabelled glucosamine derivatives, and the migration of the radiolabel was monitored. Mild-base hydrolysis of the isolated peptidoglycan (to release ester-linked acetate) from cells grown in the presence of 40 microM [acetyl-3H]N-acetyl-D-glucosamine resulted in the release of [3H]acetate, as detected by high-pressure liquid chromatography. The inclusion of either acetate, pyruvate, or acetyl phosphate, each at 1 mM final concentration, did not result in a diminution of mild-base-released [3H]acetate levels. No such release of [3H]acetate was observed with peptidoglycan isolated from either Escherichia coli incubated with the same radiolabel or P. mirabilis grown with [1,6-3H]N-acetyl-D-glucosamine or D-[1-14C]glucosamine. These observations support a hypothesis that O acetylation occurs by N----O acetyl transfer within the sacculus. A decrease in [3H]acetate release by mild-base hydrolysis was observed with the peptidoglycan of P. mirabilis cultures incubated in the presence of antagonists of peptidoglycan biosynthesis, penicillin G and D-cycloserine. The absence of free-amino sugars in the peptidoglycan of P. mirabilis but the detection of glucosamine in spent culture broths implies that N----O transacetylation is intimately associated with peptidoglycan turnover.

Acetates↗
PubMed1998

Characterization of Proteus mirabilis precocious swarming mutants: identification of rsbA, encoding a regulator of swarming behavior.

Proteus mirabilis swarming behavior is characterized by the development of concentric rings of growth that are formed as cyclic events of swarmer cell differentiation, swarming migration, and cellular differentiation are repeated during colony translocation across a surface. This cycle produces the bull's-eye colony often associated with cultures of P. mirabilis. How the cells communicate with one another to coordinate these perfectly synchronized rings is presently unknown. We report here the identification of a genetic locus that, when mutated, results in a precocious swarming phenotype. These mutants are defective in the temporal control of swarming migration and start swarming ca. 60 min sooner than wild-type cells. Unlike the wild type, precocious swarming mutants are also constitutive swarmer cells and swarm on minimal agar medium. The defects were found to be localized to a 5.4-kb locus on the P. mirabilis genome encoding RsbA (regulator of swarming behavior) and the P. mirabilis homologs to RcsB and RcsC. RsbA is homologous to membrane sensor histidine kinases of the two-component family of regulatory proteins, suggesting that RsbA may function as a sensor of environmental conditions required to initiate swarming migration. Introduction of a rsbA mutation back into the wild type via allelic-exchange mutagenesis reconstructed the precocious swarming phenotype, which could be complemented in trans by a plasmid-borne copy of rsbA. Overexpression of RsbA in wild-type cells resulted in precocious swarming, suggesting that RsbA may have both positive and negative functions in regulating swarming migration. A possible model to describe the role of RsbA in swarming migration is discussed.

Amino Acid Sequence↗
PubMed1980

Typing of Proteus mirabilis by bacteriocin production and sensitivity as a possible epidemiological marker.

Two bacteriocin typing methods, based on bacteriocin production and bacteriocin sensitivity, were developed to aid in the separation of strains of Proteus mirabilis. One hundred sixty-two isolates of P. mirabilis and 10 Cradock-Watson bacteriocin producers were grown inproteose peptone no. 3 broth and induced with mitomycin C under culture conditions found optimum for bacteriocin production. Crude bacteriocin lysates were spotted on 186 indicator strains, and after incubation for 18 h at 35 degrees C, positive zones of inhibition were recorded. A cluster analysis computer program was used to select 16 bacteriocin-producing and 16 indicator strains for inclusion in two bacteriocin typing sets. One hundred clinical isolates of P. mirabilis were differentiated by bacteriocin sensitivity into 41 distinct patterns, with 72% of the strains typable, whereas typing by bacteriocin production demonstrated 29 separate lysis patterns among the 80% typable strains. Combining the results of each typing method resulted in 72 individual bacteriocin production-sensitivity patterns and 91% of the isolates typed. Typing 14 epidemic strains by bacteriocin production revealed that 13 of 14 strains were identical, whereas only 2 of 14 strains were typable by bacteriocin sensitivity. Electron microscopy of partially purified bacteriocin revealed tail components of contractile bacteriophages. Standard bacteriocin lysates were destroyed by boiling for 1 h. In addition, all bacteriocin lysates tested were resistant to trypsin. The use of our bacteriocin production typing method against the presently selected 16 standard indicator strains is recommended for the investigation of any cases of suspected P. mirabilis cross-infections within hospitals.

Bacteriocins↗
PubMed1993

Arbitrarily primed polymerase chain reaction provides rapid differentiation of Proteus mirabilis isolates from a pediatric hospital.

During a systematic survey, maternal carriage of Proteus mirabilis was found over a 25-day period in 18 pregnant women admitted to the delivery ward of our hospital maternity. Five neonates born to these mothers were found to be colonized with P. mirabilis. We report here on the use of DNA fingerprinting by the arbitrarily primed polymerase chain reaction technique (AP-PCR) for the epidemiological investigation of this sudden outbreak. This approach was compared with the analysis of restriction fragment length polymorphisms of ribosomal DNA regions (ribotyping). Results of the AP-PCR and of ribotyping were in complete agreement in showing the genetic unrelatedness of the isolates obtained from each mother. Moreover, the results showed mother-to-infant vertical transmission of P. mirabilis in the neonates. AP-PCR is a rapid and discriminative method which seems particularly well suited to the epidemiological study of P. mirabilis.

Bacterial Typing Techniques↗
PubMed2003

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↗
PubMed2003

Nosocomial outbreak of infections by Proteus mirabilis that produces extended-spectrum CTX-M-2 type beta-lactamase.

Nineteen multidrug-resistant Proteus mirabilis strains were isolated from 19 patients suffering from infections probably caused by P. mirabilis. These strains were recovered from urine or other urogenital specimens of 16 inpatients and three outpatients with a hospitalization history in a urology ward of Funabashi Medical Center, from July 2001 to August 2002. These strains demonstrated resistance to cefotaxime, ceftriaxone, cefpodoxime, and aztreonam, while they were highly susceptible to ceftazidime (MIC, </=0.5 micro g/ml). The resistance level of these strains to cefotaxime was decreased by the presence of clavulanic acid. Therefore, the strains were speculated to produce extended-spectrum class A beta-lactamases. These strains were later found to carry bla(CTX-M-2) genes by both PCR and sequencing analyses. The profiles of SmaI-digested genomic DNA of 19 isolates were distinguished into five different clusters by biased sinusoidal field gel electrophoresis. Four of them, consisting of 18 isolates, were suggested to be a clonal expansion. These findings suggested that a nosocomial outbreak of infections by CTX-M-2-producing P. mirabilis had occurred in our medical center. Most patients suffered from urogenital malignancies with long-term catheterization. Cefazolin, cefoperazone-sulbactam, and/or levofloxacin were mostly administered to the patients, but these agents seemed ineffective for eradication of CTX-M-2 producers. Early recognition and rapid identification of colonizing antimicrobial-resistant bacteria, including CTX-M-2-producing P. mirabilis, would be the most effective measures to cope with further spread of this kind of hazardous microorganism in clinical environments.

Aged↗
PubMed1995

Decrease in anti-Proteus mirabilis but not anti-Escherichia coli antibody levels in rheumatoid arthritis patients treated with fasting and a one year vegetarian diet.

OBJECTIVE: To measure Proteus mirabilis and Escherichia coli antibody levels in patients with rheumatoid arthritis (RA) during treatment by vegetarian diet. METHODS: Sera were collected from 53 RA patients who took part in a controlled clinical trial of fasting and a one year vegetarian diet. P mirabilis and E coli antibody levels were measured by an indirect immunofluorescence technique and an enzyme immunoassay, respectively. RESULTS: The patients on the vegetarian diet had a significant reduction in the mean anti-proteus titres at all time points during the study, compared with baseline values (all p < 0.05). No significant change in titre was observed in patients who followed an omnivorous diet. The decrease in anti-proteus titre was greater in the patients who responded well to the vegetarian diet compared with diet non-responders and omnivores. The total IgG concentration and levels of antibody against E coli, however, were almost unchanged in all patient groups during the trial. The decrease from baseline in proteus antibody levels correlated significantly (p < 0.001) with the decrease in a modified Stoke disease activity index. CONCLUSION: The decrease in P mirabilis antibody levels in the diet responders and the correlation between the decrease in proteus antibody level and decrease in disease activity supports the suggestion of an aetiopathogenetic role for P mirabilis in RA.

Antibodies, Bacterial↗
PubMed2002

Emerging antimicrobial resistances among Proteus mirabilis in Europe: report from the MYSTIC Program (1997-2001). Meropenem Yearly Susceptibility Test Information Collection.

Resistance patterns that are currently problematic in Europe can vary greatly within the same species over time, among various patient populations and among geographic regions on the same continent. The results from the Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program, which monitors carbapenem resistance rates in institutions using meropenem, were used to determine resistance differences among Proteus mirabilis. MIC results from 688 P. mirabilis strains were classified into 4 patient care groups: ICU (n=426), neutropenia patients (NP; n=145), general wards (n=97) and cystic fibrosis patients (CF; n=20). A total of 40 centers from 12 European countries have participated since 1997, divided into 3 geographic regions (East, North, South). All testing was performed by NCCLS reference methods and interpretive criteria, including screening of extended-spectrum beta-lactamase (ESBL) phenotypes. Over the monitored interval the resistance rates varied for each agent without a clear trend toward a greater rate. Rank order of susceptibility was: meropenem (99%) > piperacillin/tazobactam (TAZ; 96%) > cefepime (95%) > ceftazidime (CAZ; 94%) > imipenem (IPM; 92%). Ciprofloxacin (CIP) was the least active agent tested (MIC90 4 microg/ml; 86% susceptible). Unexpectedly, 3.6% of P. mirabilis were imipenem-resistant (MIC, > or = 16 microg/ml). Greater rates of resistance were found for strains from NP and CF patients, and from eastern or southern European sites, usually associated with epidemic clusters. Generally susceptible species such as P. mirabilis have recently emerged as therapeutic problems in European medical centers following mutations that compromise CIP, CAZ and aminoglycoside use. Imipenem also showed decreased susceptibility of greater than 7% compared to less than 1% for meropenem. Continued surveillance by the MYSTIC Program appears to be a prudent practice to focus effective empiric treatment regimens.

Anti-Bacterial Agents↗
PubMed2003

Polymer surface properties and their effect on the adhesion of Proteus mirabilis.

A problem encountered in patients undergoing long-term catheterization of the urinary tract is that of encrustation and blockage of the catheter by crystalline bacterial biofilms. This is principally caused by the action of the urease-producing pathogen Proteus mirabilis. A major aim of this work is to develop materials resistant to encrustation. Here, the effects of polymer surface properties on the adhesion of P. mirabilis are examined. Spin-coated polymer films were characterized through contact angle measurements to give the Lifschitz-van der Waals, electron acceptor and electron donor terms of the surface free energy, gamma(s)LW, gamma(s)+ and gamma(s)- respectively. A parallel-plate flow cell was used to assess adhesion to these polymer films of P. mirabilis suspended in an aqueous phosphate buffer, pH 7.4, ionic strength 0.26 mol/kg. P. mirabilis was found to adhere significantly less (p < 0.02) to films of agarose, poly(2-hydroxyethylmethacrylate) and cross-linked poly(vinyl alcohol) than to more hydrophobic materials. These polymer films were found to be strongly electron donating, i.e. possessing large gamma(s)-. Films examined using scanning electron microscopy mostly showed no evidence of roughness down to a scale of 1-10 microm. The better performance is thought to be due to a repulsive interaction with the bacterial surface caused by acid/base-type interactions.

Bacterial Adhesion↗