SHORT COMMUNICATIONS Hydrophobic Surface Properties of Bordetella bronchiseptica X-mode Cells and Their Possible Role in Adherence to Porcine Nasal Mucosa Hitoshi Ishikawa and Yasuro Isayama
ABSTRACT
Bordetella bronchiseptica strains examined to determine whether the surface hydrophobicity of the bacteria correlates with their adherence to porcine nasal epithelial cells. The relative hydrophobicity of the bacteria, measured by their retention to a column of hydrophobic phenylSepharose gel and their aggregation in ammonium sulfate solution, correlated well with their adhesive properties. Phase I cells in X-mode, which adhered well to the epithelial cells, were conspicuously hydrophobic. The cells in C-mode and degraded phases, which adhered poorly to the epithelial cells, were relatively hydrophilic. These observations provide evidence for the suspected role of hydrophobic interactions in the adherence of B. bronchiseptica to porcine nasal were
mucosa.
RESUME
Cette etude avait pour objectif de determiner s'il y avait une correlation directe entre l'hydrophobicite de la surface des cellules de Bordetella bronchiseptica et leur capacite a adherer aux cellules de l'epithelium nasal de porcs. L'hydrophobicite
relative des bacteries a ete mesuree par leur degre de retention a une colonne d'un gel phenyl-Sepharose hydrophobe et par leur capacite d'aggregation en presence d'une solution de sulfate d'ammonium. Une correlation positive a ete demontree entre l'hydrophobicite et les proprietes d'adhesion des bacteries aux cellules epitheliales. Les bacteries en phase I et mode X, qui adheraient bien aux cellules epitheliales etaient vraisemblablement hydrophobes. Les bacteries appartenant aux autres phases et en mode C, qui adheraient peu aux cellules epitheliales, etaient relativement hydrophiles. Ces observations appuient l'hypothese que les proprietes hydrophobes ont un r'le dans l'adherence de B. bronchiseptica aux cellules de la muqueuse nasale des porcs.
interactions or differences in surface charges between bacterial and host cell surfaces, may also contribute to the increased adherence by functioning at different stages of attachment. Recent studies suggest that the surface hydrophobicity of certain bacteria plays a role in the host-parasite recognition (1-5). Since the membrane surfaces of eukaryotic cells have hydrophobic properties, it seems likely that the adherence of bacteria to host cells is mediated, at least in part, by hydrophobic interactions. Actually, in a series of studies on the surface hydrophobicity of a variety of bacterial species, Rosenberg et al attested to the fact that the ability of a bacterium to attach to epithelial cells correlated with its surface hydrophobicity (6-9).
INTRODUCTION
atrophic rhinitis in swine, experiences phase variation (from phase I to rough
Bacterial adherence is the final stage in the association of microbes with host tissue which initiates infection. The prerequisites for adherence include the in vivo synthesis of bacterial adhesins which allow the bacteria to bind to their specific receptors on target cells. Nonspecific interactions, which depend on physicochemical forces such as hydrophobic
phase) (10, 1 1). Changes in the growth environment may also cause a reversible alteration in the phenotype of an entire phase I population, which is termed antigenic modulation (from Xto C-mode) (12). In colony morphologies, C-mode resembles phase III phenotype but differs from X-mode (typical phase I phenotype). Phase variants and C-mode cells are charac-
Bordetella bronchiseptica, an important cause of respiratory tract disease and a frequent cause of
Hokkaido Research Station, National Institute of Animal Health, Hitsujigaoka, Toyohira-ku, Sapporo, 004, Japan. Present address of H. Ishikawa: Microbiological Diagnosis Laboratory, Systematic Diagnosis Research Division, National Institute of Animal Health, Tsukuba, Ibaraki, 305, Japan. Present address of Y. Isayama: Department of Immunology, College of Environmental Health, Azabu University, Sagamihara, Kanagawa, 229, Japan. Submitted July 21, 1989.
296
Can J Vet Res 1990; 54: 296-298
RESULTS method adapted from that of Smyth et al (20) with phenyl-Sepharose CL-4B Bacterial suspensions of B. bronchi(Pharmacia Fine Chemicals, Uppsala, Sweden). Columns comprised Pasteur septica strains were chromatographed pipettes (internal diameter, 5 mm) on phenyl-Sepharose columns. Repreplugged with glass wool. Gel beds were sentative data from triplicate columns packed to a height of 30 mm (ca 0.6 are shown (Table I). X-mode orgamL gel bed volume) and equilibrated nisms of strain A 19 had strong affinity with PB. Portions (100,uL) of bacte- for the gel despite the use of buffer of rial suspensions were applied onto the low ionic strength, which is unfavoragel beds, which were washed with 4 ble to hydrophobic interactions. The mL of PB. The optical densities of the extent of retention to the gel was eluates were measured at 550 nm and approximately 95%. There was little compared with those of the approp- interstrain variation in the degree of riately diluted portions of the original affinity among X-mode organisms. Csuspensions (i.e. 100 ,uL of the original mode cells as well as phase variants of suspension in 4 mL of PB). The strain A19, on the other hand, retention of the bacteria on the exhibited relatively weak affinity for column was expressed as a percentage the gel matrix with less than 10% of the of the total amount of bacteria applied applied cells being retained. Similar observations were also obtained with to the column. The SAT of Lindahl et al (21) was the cells of other strains in C-mode or also used to measure relative surface degraded phases. The results of SAT were similar to hydrophobicity of the bacteria. Each bacterial suspension (25 MAL) was mixed those obtained by HIC (Table I). Xon a glass slide with an equal volume of mode cells were aggregated by a low ammonium sulfate in PB, the concen- concentration of ammonium sulfate trations of which were 2, 1, 0.5, 0.25, (0.0625 M), indicating a high degree 0.125 and 0.0625 M. The bacteria-salt of surface hydrophobicity. Aggregasolutions were mixed by rocking gently tion of C-mode cells and phase for 2 min at ambient temperature and variants occurred only when much then observed for aggregation. The higher concentrations of the salt (1.0 SAT value represents the lowest or 2.0 M) were added, indicating concentration of ammonium sulfate lower degrees of surface hydrogiving visible aggregation. phobicity. The adherence of bacteria was X-mode organisms adhered well to MATERIALS AND METHODS examined using epithelial cells porcine nasal epithelial cells, whereas Strains of B. bronchiseptica used in obtained from ventral turbinate the organisms in C-mode or degraded the present study were phase I strain mucosae of pigs as described else- phases showed feeble adherence to the A 19 (a primary isolate from a pig where (13,18). same cells (Table I). affected with atrophic rhinitis) and its substrains A19-CV200 (phase II), A19-CV300 (phase III) and A19CV400 (rough phase). Two other TABLE I. Cell surface hydrophobicity and adhesiveness of B. bronchiseptica phase I strains (H16 and S1) and their Concentration (M) of substrains in degraded phases were % Retention on ammonium sulfate also examined. Methods for induction Phase required for phenyl-Sepharose of phase variants as well as C-mode Strain column Adhesivenessa aggregation (Mode) cells have been described in detail A19 1 (X) 13.1 ± 2.0 0.0625 95.4 (11,13). Cultures were maintained on 9.5 2.0 0.4 0.1 1(C) 11 0.7 0.4 7.1 2.0 Bordet-Gengou agar (Difco LaboraIII 6.8 0.3 ± 0.2 2.0 tories, Detroit, Michigan) containing 0.1 0.1 1.0 Rough 3.3 7% defibrinated sheep blood and 1 (X) H16 13.3 ±4.8 0.0625 92.3 stored at 4° C. 1 (C) 9.7 0.8 ± 0.5 1.0 Bacteria grown on Bordet-Gengou II 8.1 1.0 0.7 0.4 agar for 18 h were harvested, washed III 1.0 1.0 0.3 0.1 twice, and suspended in 2 mM sodium Sl 0.0625 16.4 ± 5.4 92.5 I (X) phosphate buffer (PB; pH 6.8) to a 1 (C) 1.0 0.4 ± 0.2 9.1 III 4.0 1.0 0.2±0.1 density of 4 x 109 cells/mL. 0.1 ± 0.1 1.0 1.0 Rough Hydrophobic interaction chroma± SD of cell was determined from triplicate assays tography was performed by the aMean number bacteria attached per epithelial
erized by loss or attenuation of capsular antigen (10,1 1,13-15) as well as loss of virulence (16,17). Previous studies have demonstrated that the pathogenic organisms in X-mode attach to the surface of porcine nasal mucosa (13,17,18). Nonpathogenic organisms either in C-mode or in degraded phases (phases II, III and rough), on the contrary, have been shown not to attach to the target tissue (13). Accordingly, adherence is thought to be of major importance to the establishment of this infection (17). Recent data from our laboratory indicate that the adherence of B. bronchiseptica to porcine nasal epithelial cells is mediated by X-mode cell-specific adhesin which is not produced by nonpathogenic organisms (19). However, little is known about the implication of physicochemical surface properties in the stage of nonspecific adherence which may precede specific adherence. The purpose of the present study was to measure the relative surface hydrophobicity, by hydrophobic interaction chromatography (HIC) and salt aggregation test (SAT), of B. bronchiseptica organisms and to relate this property to adherence to porcine nasal epithelial cells.
297
DISCUSSION
competition of free mucus for the receptors on the epithelial cells. This study did not corroborate the role of surface hydrophobicity as an independent variable in promoting bacterial adherence. However, the pronounced hydrophobic and adhesive properties of B. bronchiseptica Xmode cells in vitro might conceivably promote intensive colonization of porcine nasal cavity if they occurred in
Phase I cells of B. bronchiseptica 9. strains grown in X-mode were conspicuously hydrophobic. Conversely, reduced surface hydrophobicity was 10. observed when the strains were grown in C-mode or degraded phases. Among the cells in X-mode as well as 11. in C-mode and degraded phases, no fimbriation was observed when they were negatively stained and examined vivo. by electronmicroscopy (data not 12. shown). These indicate that cell 13. surface components (other than ACKNOWLEDGMENTS fimbriae), lost on transition from X-to C-mode or from phase I to degraded The authors wish to thank Dr. M. phases, may confer on the organism for his guidance in 14. Nakagawa much of its surface hydrophobicity. electronmicroscopy. A positive correlation was found between the hydrophobicity levels of the bacteria and their adhesive 15. properties to the epithelial cells. The REFERENCES hydrophobic surface properties of microorganisms are thought to pro- 1. VAN OSS CJ. Phagocytosis as a surface vide the driving forces for phenomenon. Ann Rev Microbiol 1978; 32: 19-39. prokaryotic-eukaryotic cell surface 16. WEISS E, ROSENBERG M, JUDES H, 2. interactions through the displacement ROSENBERG E. Cell-surface hydrophoof water molecules fixed on these two bicity of adherent oral bacteria. Curr hydrophobic surfaces and the formaMicrobiol 1982; 7: 125-128. tion of an adhesive bond by a gain of 3. SVANBERG M, WESTERGREN G, 17. OLSSON J. Oral implantation in humans entropy. These driving forces may of Streptococcus mutans strains with serve to counteract the mutually different degrees of hydrophobicity. Infect repulsive forces that exist naturally Immun 1984; 43: 817-821. between negatively charged microbes 4. GARBER N, SHARON N, SHOHET D, 18. LAM JS, DOYLE RJ. Contribution of and host cells. From this study it is hydrophobicity to hemagglutination reacapparent that the surface of B. tions of Pseudomonas aeruginosa. Infect 19. bronchiseptica X-mode organism Immun 1985; 50: 336-337. contains nonspecific forces, i.e. 5. WOOD-HELIE SJ, DALTON HP, hydrophobic properties, besides speSHADOMY S. Hydrophobic and adherence properties of Clostridium difficile. Eur cific ones (19) which may influence its J Clin Microbiol 1986; 5: 441-445. 20. eventual adherence to the host cell ROSENBERG M, PERRY A, BAYER surface. Perhaps the nonspecific 6. EA, GUTNICK DL, ROSENBERG E, hydrophobic interactions in vivo OFEK I. Adherence of Acinetobacter constitute an earlier, important stage calcoaceticus RAG-1 to human epithelial cells and to hexadecane. Infect Immun in attachment processes prerequisite 1981; 33: 29-33. to the later, more specific adhesin7. ROSENBERG M, ROSENBERG E, receptor interactions. The hydroJUDES H, WEISS E. Bacterial adherence 21. phobic characteristic may enable the to hydrocarbons and to surfaces in the oral bacterium to have constant access to cavity. FEMS Microbiol Lett 1983; 20: 1-5. porcine nasal mucosa and provide a 8. ROSENBERG E, GOTTLIEB A, ROSENBERG M. Inhibition of bacterial adherence counterforce which overcomes the
298
to hydrocarbons and epithelial cells by emulsan. Infect Immun 1983; 39: 10241028. ROSENBERG M, KJELLEBERG S. Hydrophobic interactions: role in bacterial adhesion. Adv Microb Ecol 1986; 9: 353393. NAKASE Y. Studies on Haemophilus bronchisepticus. 11. Phase variation of H. bronchisepticus. Kitasato Arch Exp Med 1957; 30: 73-78 ISHIKAWA H, ISAYAMA Y. Bordetella bronchiseptica phase variation induced by crystal violet. J Clin Microbiol 1986; 23: 235-239. LACEY BW. Antigenic modulation of Bordetellapertussis. J Hyg 1960; 58: 57-93. ISHIKAWA H, ISAYAMA Y. Effect of antigenic modulation and phase variation on adherence of Bordetella bronchiseptica to porcine nasal epithelial cells. Am J Vet Res 1987; 48: 1689-1691. NAKASE Y. Studies on Haemophilus bronchisepticus. 1. The antigenic structures of H. bronchisepticus from guinea pig. Kitasato Arch Exp Med 1957; 30: 57-72. ELIAS B, KRUGER M, RATZ F. Epizootiologische Untersuchungen der Rhinitis atrophicans des Schweines. 11. Biologische Eigenschaften der von Schweinen isolierten Bordetella bronchiseptica Stamme. Zentralbl Veterinaermed [B] 1982; 29: 619-635. NAKASE Y. Studies on Haemophilus bronchisepticus. 111. Differences of biological properties between phase I and phase III of H. bronchisepticus. Kitasato Arch Exp Med 1957; 30: 79-84. YOKOMIZO Y, SHIMIZU T. Adherence of Bordetella bronchiseptica to swine nasal epithelial cells and its possible role in virulence. Res Vet Sci 1979; 27: 15-21. ISHIKAWA H, ISAYAMA Y. Evidence for sialyl glycoconjugates as receptors for Bordetella bronchiseptica on swine nasal mucosa. Infect Immun 1987; 55: 1607-1609. ISHIKAWA H, ISAYAMA Y. Bovine erythrocyte-agglutinin as a possible adhesin of Bordetella bronchiseptica responsible for binding to porcine nasal epithelium. J Med Microbiol 1988; 26: 205-209. SMYTH CJ, JONSSON P, OLSSON E, SODERLIND 0, ROSENGREN J, HJERTEN S, WADSTROM T. Differences in hydrophobic surface characteristics of porcine enteropathogenic Escherichia coli with or without K88 antigen as revealed by hydrophobic interaction chromatography. Infect Immun 1978; 22: 462-472. LINDAHL M, FARIS A, WADSTROM T, HJERTEN S. A new test based on 'salting out' to measure relative surface hydrophobicity of bacterial cells. Biochim Biophys Acta 1981; 667: 471-476.
ABSTRACT
Bordetella bronchiseptica strains examined to determine whether the surface hydrophobicity of the bacteria correlates with their adherence to porcine nasal epithelial cells. The relative hydrophobicity of the bacteria, measured by their retention to a column of hydrophobic phenylSepharose gel and their aggregation in ammonium sulfate solution, correlated well with their adhesive properties. Phase I cells in X-mode, which adhered well to the epithelial cells, were conspicuously hydrophobic. The cells in C-mode and degraded phases, which adhered poorly to the epithelial cells, were relatively hydrophilic. These observations provide evidence for the suspected role of hydrophobic interactions in the adherence of B. bronchiseptica to porcine nasal were
mucosa.
RESUME
Cette etude avait pour objectif de determiner s'il y avait une correlation directe entre l'hydrophobicite de la surface des cellules de Bordetella bronchiseptica et leur capacite a adherer aux cellules de l'epithelium nasal de porcs. L'hydrophobicite
relative des bacteries a ete mesuree par leur degre de retention a une colonne d'un gel phenyl-Sepharose hydrophobe et par leur capacite d'aggregation en presence d'une solution de sulfate d'ammonium. Une correlation positive a ete demontree entre l'hydrophobicite et les proprietes d'adhesion des bacteries aux cellules epitheliales. Les bacteries en phase I et mode X, qui adheraient bien aux cellules epitheliales etaient vraisemblablement hydrophobes. Les bacteries appartenant aux autres phases et en mode C, qui adheraient peu aux cellules epitheliales, etaient relativement hydrophiles. Ces observations appuient l'hypothese que les proprietes hydrophobes ont un r'le dans l'adherence de B. bronchiseptica aux cellules de la muqueuse nasale des porcs.
interactions or differences in surface charges between bacterial and host cell surfaces, may also contribute to the increased adherence by functioning at different stages of attachment. Recent studies suggest that the surface hydrophobicity of certain bacteria plays a role in the host-parasite recognition (1-5). Since the membrane surfaces of eukaryotic cells have hydrophobic properties, it seems likely that the adherence of bacteria to host cells is mediated, at least in part, by hydrophobic interactions. Actually, in a series of studies on the surface hydrophobicity of a variety of bacterial species, Rosenberg et al attested to the fact that the ability of a bacterium to attach to epithelial cells correlated with its surface hydrophobicity (6-9).
INTRODUCTION
atrophic rhinitis in swine, experiences phase variation (from phase I to rough
Bacterial adherence is the final stage in the association of microbes with host tissue which initiates infection. The prerequisites for adherence include the in vivo synthesis of bacterial adhesins which allow the bacteria to bind to their specific receptors on target cells. Nonspecific interactions, which depend on physicochemical forces such as hydrophobic
phase) (10, 1 1). Changes in the growth environment may also cause a reversible alteration in the phenotype of an entire phase I population, which is termed antigenic modulation (from Xto C-mode) (12). In colony morphologies, C-mode resembles phase III phenotype but differs from X-mode (typical phase I phenotype). Phase variants and C-mode cells are charac-
Bordetella bronchiseptica, an important cause of respiratory tract disease and a frequent cause of
Hokkaido Research Station, National Institute of Animal Health, Hitsujigaoka, Toyohira-ku, Sapporo, 004, Japan. Present address of H. Ishikawa: Microbiological Diagnosis Laboratory, Systematic Diagnosis Research Division, National Institute of Animal Health, Tsukuba, Ibaraki, 305, Japan. Present address of Y. Isayama: Department of Immunology, College of Environmental Health, Azabu University, Sagamihara, Kanagawa, 229, Japan. Submitted July 21, 1989.
296
Can J Vet Res 1990; 54: 296-298
RESULTS method adapted from that of Smyth et al (20) with phenyl-Sepharose CL-4B Bacterial suspensions of B. bronchi(Pharmacia Fine Chemicals, Uppsala, Sweden). Columns comprised Pasteur septica strains were chromatographed pipettes (internal diameter, 5 mm) on phenyl-Sepharose columns. Repreplugged with glass wool. Gel beds were sentative data from triplicate columns packed to a height of 30 mm (ca 0.6 are shown (Table I). X-mode orgamL gel bed volume) and equilibrated nisms of strain A 19 had strong affinity with PB. Portions (100,uL) of bacte- for the gel despite the use of buffer of rial suspensions were applied onto the low ionic strength, which is unfavoragel beds, which were washed with 4 ble to hydrophobic interactions. The mL of PB. The optical densities of the extent of retention to the gel was eluates were measured at 550 nm and approximately 95%. There was little compared with those of the approp- interstrain variation in the degree of riately diluted portions of the original affinity among X-mode organisms. Csuspensions (i.e. 100 ,uL of the original mode cells as well as phase variants of suspension in 4 mL of PB). The strain A19, on the other hand, retention of the bacteria on the exhibited relatively weak affinity for column was expressed as a percentage the gel matrix with less than 10% of the of the total amount of bacteria applied applied cells being retained. Similar observations were also obtained with to the column. The SAT of Lindahl et al (21) was the cells of other strains in C-mode or also used to measure relative surface degraded phases. The results of SAT were similar to hydrophobicity of the bacteria. Each bacterial suspension (25 MAL) was mixed those obtained by HIC (Table I). Xon a glass slide with an equal volume of mode cells were aggregated by a low ammonium sulfate in PB, the concen- concentration of ammonium sulfate trations of which were 2, 1, 0.5, 0.25, (0.0625 M), indicating a high degree 0.125 and 0.0625 M. The bacteria-salt of surface hydrophobicity. Aggregasolutions were mixed by rocking gently tion of C-mode cells and phase for 2 min at ambient temperature and variants occurred only when much then observed for aggregation. The higher concentrations of the salt (1.0 SAT value represents the lowest or 2.0 M) were added, indicating concentration of ammonium sulfate lower degrees of surface hydrogiving visible aggregation. phobicity. The adherence of bacteria was X-mode organisms adhered well to MATERIALS AND METHODS examined using epithelial cells porcine nasal epithelial cells, whereas Strains of B. bronchiseptica used in obtained from ventral turbinate the organisms in C-mode or degraded the present study were phase I strain mucosae of pigs as described else- phases showed feeble adherence to the A 19 (a primary isolate from a pig where (13,18). same cells (Table I). affected with atrophic rhinitis) and its substrains A19-CV200 (phase II), A19-CV300 (phase III) and A19CV400 (rough phase). Two other TABLE I. Cell surface hydrophobicity and adhesiveness of B. bronchiseptica phase I strains (H16 and S1) and their Concentration (M) of substrains in degraded phases were % Retention on ammonium sulfate also examined. Methods for induction Phase required for phenyl-Sepharose of phase variants as well as C-mode Strain column Adhesivenessa aggregation (Mode) cells have been described in detail A19 1 (X) 13.1 ± 2.0 0.0625 95.4 (11,13). Cultures were maintained on 9.5 2.0 0.4 0.1 1(C) 11 0.7 0.4 7.1 2.0 Bordet-Gengou agar (Difco LaboraIII 6.8 0.3 ± 0.2 2.0 tories, Detroit, Michigan) containing 0.1 0.1 1.0 Rough 3.3 7% defibrinated sheep blood and 1 (X) H16 13.3 ±4.8 0.0625 92.3 stored at 4° C. 1 (C) 9.7 0.8 ± 0.5 1.0 Bacteria grown on Bordet-Gengou II 8.1 1.0 0.7 0.4 agar for 18 h were harvested, washed III 1.0 1.0 0.3 0.1 twice, and suspended in 2 mM sodium Sl 0.0625 16.4 ± 5.4 92.5 I (X) phosphate buffer (PB; pH 6.8) to a 1 (C) 1.0 0.4 ± 0.2 9.1 III 4.0 1.0 0.2±0.1 density of 4 x 109 cells/mL. 0.1 ± 0.1 1.0 1.0 Rough Hydrophobic interaction chroma± SD of cell was determined from triplicate assays tography was performed by the aMean number bacteria attached per epithelial
erized by loss or attenuation of capsular antigen (10,1 1,13-15) as well as loss of virulence (16,17). Previous studies have demonstrated that the pathogenic organisms in X-mode attach to the surface of porcine nasal mucosa (13,17,18). Nonpathogenic organisms either in C-mode or in degraded phases (phases II, III and rough), on the contrary, have been shown not to attach to the target tissue (13). Accordingly, adherence is thought to be of major importance to the establishment of this infection (17). Recent data from our laboratory indicate that the adherence of B. bronchiseptica to porcine nasal epithelial cells is mediated by X-mode cell-specific adhesin which is not produced by nonpathogenic organisms (19). However, little is known about the implication of physicochemical surface properties in the stage of nonspecific adherence which may precede specific adherence. The purpose of the present study was to measure the relative surface hydrophobicity, by hydrophobic interaction chromatography (HIC) and salt aggregation test (SAT), of B. bronchiseptica organisms and to relate this property to adherence to porcine nasal epithelial cells.
297
DISCUSSION
competition of free mucus for the receptors on the epithelial cells. This study did not corroborate the role of surface hydrophobicity as an independent variable in promoting bacterial adherence. However, the pronounced hydrophobic and adhesive properties of B. bronchiseptica Xmode cells in vitro might conceivably promote intensive colonization of porcine nasal cavity if they occurred in
Phase I cells of B. bronchiseptica 9. strains grown in X-mode were conspicuously hydrophobic. Conversely, reduced surface hydrophobicity was 10. observed when the strains were grown in C-mode or degraded phases. Among the cells in X-mode as well as 11. in C-mode and degraded phases, no fimbriation was observed when they were negatively stained and examined vivo. by electronmicroscopy (data not 12. shown). These indicate that cell 13. surface components (other than ACKNOWLEDGMENTS fimbriae), lost on transition from X-to C-mode or from phase I to degraded The authors wish to thank Dr. M. phases, may confer on the organism for his guidance in 14. Nakagawa much of its surface hydrophobicity. electronmicroscopy. A positive correlation was found between the hydrophobicity levels of the bacteria and their adhesive 15. properties to the epithelial cells. The REFERENCES hydrophobic surface properties of microorganisms are thought to pro- 1. VAN OSS CJ. Phagocytosis as a surface vide the driving forces for phenomenon. Ann Rev Microbiol 1978; 32: 19-39. prokaryotic-eukaryotic cell surface 16. WEISS E, ROSENBERG M, JUDES H, 2. interactions through the displacement ROSENBERG E. Cell-surface hydrophoof water molecules fixed on these two bicity of adherent oral bacteria. Curr hydrophobic surfaces and the formaMicrobiol 1982; 7: 125-128. tion of an adhesive bond by a gain of 3. SVANBERG M, WESTERGREN G, 17. OLSSON J. Oral implantation in humans entropy. These driving forces may of Streptococcus mutans strains with serve to counteract the mutually different degrees of hydrophobicity. Infect repulsive forces that exist naturally Immun 1984; 43: 817-821. between negatively charged microbes 4. GARBER N, SHARON N, SHOHET D, 18. LAM JS, DOYLE RJ. Contribution of and host cells. From this study it is hydrophobicity to hemagglutination reacapparent that the surface of B. tions of Pseudomonas aeruginosa. Infect 19. bronchiseptica X-mode organism Immun 1985; 50: 336-337. contains nonspecific forces, i.e. 5. WOOD-HELIE SJ, DALTON HP, hydrophobic properties, besides speSHADOMY S. Hydrophobic and adherence properties of Clostridium difficile. Eur cific ones (19) which may influence its J Clin Microbiol 1986; 5: 441-445. 20. eventual adherence to the host cell ROSENBERG M, PERRY A, BAYER surface. Perhaps the nonspecific 6. EA, GUTNICK DL, ROSENBERG E, hydrophobic interactions in vivo OFEK I. Adherence of Acinetobacter constitute an earlier, important stage calcoaceticus RAG-1 to human epithelial cells and to hexadecane. Infect Immun in attachment processes prerequisite 1981; 33: 29-33. to the later, more specific adhesin7. ROSENBERG M, ROSENBERG E, receptor interactions. The hydroJUDES H, WEISS E. Bacterial adherence 21. phobic characteristic may enable the to hydrocarbons and to surfaces in the oral bacterium to have constant access to cavity. FEMS Microbiol Lett 1983; 20: 1-5. porcine nasal mucosa and provide a 8. ROSENBERG E, GOTTLIEB A, ROSENBERG M. Inhibition of bacterial adherence counterforce which overcomes the
298
to hydrocarbons and epithelial cells by emulsan. Infect Immun 1983; 39: 10241028. ROSENBERG M, KJELLEBERG S. Hydrophobic interactions: role in bacterial adhesion. Adv Microb Ecol 1986; 9: 353393. NAKASE Y. Studies on Haemophilus bronchisepticus. 11. Phase variation of H. bronchisepticus. Kitasato Arch Exp Med 1957; 30: 73-78 ISHIKAWA H, ISAYAMA Y. Bordetella bronchiseptica phase variation induced by crystal violet. J Clin Microbiol 1986; 23: 235-239. LACEY BW. Antigenic modulation of Bordetellapertussis. J Hyg 1960; 58: 57-93. ISHIKAWA H, ISAYAMA Y. Effect of antigenic modulation and phase variation on adherence of Bordetella bronchiseptica to porcine nasal epithelial cells. Am J Vet Res 1987; 48: 1689-1691. NAKASE Y. Studies on Haemophilus bronchisepticus. 1. The antigenic structures of H. bronchisepticus from guinea pig. Kitasato Arch Exp Med 1957; 30: 57-72. ELIAS B, KRUGER M, RATZ F. Epizootiologische Untersuchungen der Rhinitis atrophicans des Schweines. 11. Biologische Eigenschaften der von Schweinen isolierten Bordetella bronchiseptica Stamme. Zentralbl Veterinaermed [B] 1982; 29: 619-635. NAKASE Y. Studies on Haemophilus bronchisepticus. 111. Differences of biological properties between phase I and phase III of H. bronchisepticus. Kitasato Arch Exp Med 1957; 30: 79-84. YOKOMIZO Y, SHIMIZU T. Adherence of Bordetella bronchiseptica to swine nasal epithelial cells and its possible role in virulence. Res Vet Sci 1979; 27: 15-21. ISHIKAWA H, ISAYAMA Y. Evidence for sialyl glycoconjugates as receptors for Bordetella bronchiseptica on swine nasal mucosa. Infect Immun 1987; 55: 1607-1609. ISHIKAWA H, ISAYAMA Y. Bovine erythrocyte-agglutinin as a possible adhesin of Bordetella bronchiseptica responsible for binding to porcine nasal epithelium. J Med Microbiol 1988; 26: 205-209. SMYTH CJ, JONSSON P, OLSSON E, SODERLIND 0, ROSENGREN J, HJERTEN S, WADSTROM T. Differences in hydrophobic surface characteristics of porcine enteropathogenic Escherichia coli with or without K88 antigen as revealed by hydrophobic interaction chromatography. Infect Immun 1978; 22: 462-472. LINDAHL M, FARIS A, WADSTROM T, HJERTEN S. A new test based on 'salting out' to measure relative surface hydrophobicity of bacterial cells. Biochim Biophys Acta 1981; 667: 471-476.
