Proteus morgani is less frequently associated with urinary tract infections than Proteus mirabilis--an explanation

Senior, B. W.

doi:10.1099/00222615-16-3-317

Cited by 50 publications

(26 citation statements)

References 13 publications

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“…No significant differences were found between P. mirabilis and P. vulgaris in growth rates in urine and broth or in serum sensitivity. Differences in growth rates have been held responsible for differences in prevalence in urinary-tract infections of Escherichia coli and other enterobacteria (Anderson et al, 1979) and of P. mirabilis and P. morgani (Senior, 1983), but cannot account for the difference in prevalence of P. mirabilis and P. vulgaris in urinary-tract infections.…”

Section: Discussionmentioning

confidence: 99%

Uropathogenic Properties of Proteus Mirabilis and Proteus Vulgaris

Peerbooms

Verweij

Maclaren

1985

Journal of Medical Microbiology

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SUMMARY. A group of faecal isolates of Proteus vulgaris and P. mirabilis was studied for the presence of possible virulence factors such as growth rates in urine and broth, haemolysin production, hydrophobicity, sensitivity to the bactericidal activity of human serum and cell invasiveness. Differences were found in haemolysin production, cell invasiveness and experimental virulence in a mouse model. These differences might explain why P. mirabilis is much more common in human urinary-tract infections than P. vulgaris. INTRODUCTIONProteus vulgaris and P. mirabilis are common inhabitants of the human gut; Krikler (1953) reported prevalences of 17% for P. mirabilis and 5% for P. vulgaris in the faeces of healthy persons. Urinary pathogens are thought to originate mainly from the gut and it is interesting that P. mirabilis is disproportionately more frequently isolated from patients with urinary-tract infections than P. vulgaris. Senior (1 979), for example, isolated 258 strains of P. mirabilis from infected urines against only four strains of P. vulgaris, two of which were isolated together with P. mirabilis. These epidemiological data suggest that P. mirabilis is more likely to cause urinary-tract infections than P. vulgaris. As both species are very similar, genetically and biochemically (Brenner et al., 1978), a comparative study of isolates of both species could yield valuable information about bacterial properties important in the pathogenesis of urinary-tract infections. Therefore, we have compared faecal isolates of both species, isolated from the same population, with regard to several properties: experimental virulence in a mouse model, growth rates in urine and broth, haemolysin production, hydrophobicity, sensitivity to the bactericidal activity of human serum, cell invasiveness and serotype. MATERIALS AND METHODSIsolation of Proteus strains from faeces. Stool samples were obtained from patients seen in general practice. Most samples had been submitted for examination for occult blood or for suspected parasitic infestation. A suspension of the sample in phosphate-buffered saline (PBS) was inoculated in the centre of a fresh nutrient-agar plate (Oxoid). The plates were incubated for ~ ~

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Section: Discussionmentioning

confidence: 99%

Uropathogenic Properties of Proteus Mirabilis and Proteus Vulgaris

Peerbooms

Verweij

Maclaren

1985

Journal of Medical Microbiology

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“…morgani are rarely associated with urinary-tract infections (Senior, 1979). This has been explained on the basis of their slow growth rate in urine and their inability to make urine alkaline rapidly (Senior, 1983). The finding that approximately half these organisms are unable to produce haemolysin suggests that such strains are at an even greater disadvantage as potential urinary-tract pathogens.…”

Section: B W Senior a N D C Hughesmentioning

confidence: 99%

“…However, other members of the tribe Proteeae are rarely associated with urinary-tract infections and some are more often associated with diarrhoea (Senior, 1979(Senior, , 1983Senior and Leslie, 1986). Since Peerbooms et al (1983) have shown that the haemolysins produced by P. mirabilis influence the virulence of this organism for the mouse, we have investigated the frequency and characteristics of haemolysin production in clinical isolates of this and all other species in the Proteeae to see if the virulence of P. mirabilis for the urinary tract is likely to be similarly linked to haemolysin production.…”

Section: Introductionmentioning

confidence: 99%

Production and properties of haemolysins from clinical isolates of the Proteeae

Senior

1988

Journal of Medical Microbiology

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Summary.A collection of 198 clinical isolates of strains belonging to the tribe Proteeae was examined for haemolytic activity on blood agar and in Brain Heart Infusion Broth. The strains were of diverse bacteriocin and 0-antigenic types and from a wide variety of sources. They included representatives of all species of Morganella, Proteus and Providencia. Approximately half of the M . morgani strains were haemolytic on blood agar. This activity was not associated with any particular bacteriocin type. The haemolysin was also produced during exponential growth in broth and was thermolabile and calcium dependent. All P. mirabilis strains and some P. vulgaris strains were non-haemolytic on blood agar. However, most strains of the Proteus spp., irrespective of their bacteriocin and antigenic type, produced, over a short period during exponential growth in broth, a heat-stable, cell-associated calcium-independent haemolysin. A smaller proportion of P. vulgaris and P. penneri strains produced, in addition, a thermolabile, calcium-dependent haemolysin which was associated with the formation of large haemolytic zones on blood agar. The relationship of these haemolysins to Escherichia coli haemolysin and their possible role in virulence is discussed. Haemolysin production was not found in any of the 74 strains of four species of Providencia.

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“…Proteus vulgaris and also M . morganii are a common cause of opportunistic, particularly nosocomial infections in humans [30,311. A high incidence of hemolytic strains has been reported amongst extraintestinal M. morganii isolates, and a markedly higher virulence in three animal models was observed for hemolytic strains [32].…”

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Pore formation in artificial membranes by the secreted hemolysins of Proteus vulgaris and Morganella morganii

Benz

Hardie

Hughes

1994

European Journal of Biochemistry

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Lipid-bilayer experiments were performed with the related hemolysins from Proteus vulgaris and Morganella morganii (HlyA). The addition of the toxins to the aqueous phase bathing lipidbilayer membranes composed of different lipids resulted in the formation of transient ion-permeable channels. Membranes formed of pure lipids were rather inactive targets for the hemolysins as compared with lipid mixtures such as asolectin. The channels had several different substates. The major open state had single-channel conductances of 500 pS in 0.15 M KC1 at small transmembrane voltages. Experiments with different salts suggested that the hemolysin-induced channels of l? vulgaris and M . morganii were exclusively cation selective at neutral pH, caused by negative charges localized at the channel mouth. The mobility sequence of the cations within the channels was similar if not identical to their mobility sequence in the aqueous phase. The single-channel data were consistent with wide, water-filled channels with estimated minimal diameters of about 1 nm since the large organic cation Tris' can permeate the channels without any detectable interaction with its interior. Pore-forming properties of these hemolysins were compared with those of HlyA of Escherichia coli. All these toxins share common features, oligomerize probably to form pores in lipidbilayer membranes and form channels with similar properties which suggests that their structures are more or less identical. a-hemolysin (HlyA) of Escherichia coli is a member of a family of cytolysins from Gram-negative bacteria. Many of these toxins share common structural properties, especially a repeat domain in the C-terminal half of the toxin protein, and are therefore called RTX (repeats in toxin) proteins [l-31. The primary structure of HlyA has several different domains [4, 51. The C-terminus of HlyA is essential for its secretion out of the cell by the HlyB/HlyD system together with the minor outer membrane porin TolC [6-111 and its activation is catalysed by the cytoplasmic protein HlyC and involves acylation by an acyl-carrier protein [12, 131. The repeat domain binds Ca2+ and may be the essential part of the toxin for receptor recognition on the mammalian target cell but it is not essential for channel formation in lipid-bilayer membranes [14]. Further studies on the E. coli hemolysin have revealed that two other regions may also be involved in pore formation, the N-terminus and a hydrophobic domain at amino acid 177-411 [15, 161. Extensive similarity has been demonstrated between the four different hly genes of E. coli and those of the Proteacae [17, 181, and also to the hemolysins and leukotoxins of Actinobacillus Erythrocyte lysis by E. coli HlyA is characterised by three phases, an initial lag, an accelerated rate of hemolysis followed by a plateau, then a decline in rate [33]. An initial adsorption step (due to the repeat domain [l -31) may determine the lag step of erythrocyte lysis. Studies with erythrocytes and artificial membranes have demonstrated that a por...

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Proteus morgani is less frequently associated with urinary tract infections than Proteus mirabilis--an explanation

Cited by 50 publications

References 13 publications

Uropathogenic Properties of Proteus Mirabilis and Proteus Vulgaris

Uropathogenic Properties of Proteus Mirabilis and Proteus Vulgaris

Production and properties of haemolysins from clinical isolates of the Proteeae

Pore formation in artificial membranes by the secreted hemolysins of Proteus vulgaris and Morganella morganii

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