Classification of Proteus penneri lipopolysaccharides into core region serotypes.

The frequency of P. penneri isolation from hospital patients, mostly from urine and wounds, keeps on growing, and numerous isolates are multi-drug resistant. P. penneri rods produce lipopolysaccharide (LPS), which may lead to the septic shock. Until now, O-specific polysaccharide has been the best structurally and serologically characterized region of P. penneri LPS. It is worth having an insight into the serological specificity of both poly- and oligosaccharide parts of P. penneri LPS. The P. penneri core region is less structurally diverse than OPS, but still, among other enterobacterial LPS core regions, it is characterized by structural variability. In the present study, the serological reactivity of 25 P. penneri LPS core regions was analyzed by ELISA, passive immunohemolysis and Western blot technique using five polyclonal P. penneri antisera after or without their adsorption with the respective LPSs. The results allowed the assignment of the tested strains to five new core serotypes, which together with published serological studies led to the creation of the first serotyping scheme based on LPS core reactivities of 35 P. penneri and three P. mirabilis strains. Together with the O types scheme, it will facilitate assigning Proteus LPSs of clinical isolates into appropriate O and R serotypes.

Swarming growth and resistance of Proteus penneri and Proteus vulgaris strains to normal human serum.

BACKGROUND: Proteus sp. strains isolated from patients with urinary tract infection (UTI) are often insensitive to the bactericidal action of normal human serum (NHS) which poses a clinical problem. The swarming phenomenon is an especially important factor in cases of UTIs gained through the ascending route. Both these virulence factors are connected with the cell surface components of bacteria, including lipopolysaccharide (LPS). OBJECTIVES: The resistance of Proteus bacilli to the bactericidal activity of NHS and the swarming phenomenon were investigated as well as the possible relationships between these virulence factors and the chemical structure of LPS. MATERIAL AND METHODS: The research was carried out on P. penneri and P. vulgaris species. Two preparations of sera were tested with respect to the bactericidal action of NHS. The ability of bacteria to swarm was checked on broth agar plates. The length of the O-specific part of LPS was estimated after poliacrylamide gel electrophoresis (PAGE) and staining with silver nitrate. RESULTS: Among the 62 tested Proteus strains, over 62% of Proteus vulgaris and 50% of Proteus penneri strains were sensitive to the bactericidal action of NHS. However, the number of resistant strains grew dramatically when serum with blocked complement activation via the alternative pathway was used. From 102 of the Proteus sp. Strains, only few were unable to swarm over the solid surface of the media. The remaining showed diverse ability to translocate. CONCLUSIONS: There was no definite correlation between the chemical structure of the O-specific chains of lipopolysaccharides and sensitivity or resistance of the Proteus sp. strains to NHS. Also, no significant relationships were found between the length or the chemical structure of the O-specific chains of the bacterial LPSs and the swarming phenomenon.

[Proteus penneri]. / Proteus penneri.

Proteus penneri, formerly P. vulgaris biogroup 1, was recognized as a new species in 1982. This species is associated with clinical processes similar to those involving P. mirabilis and P. vulgaris and expresses similar pathogenic determinants. In clinical samples, P. penneri is mainly isolated from urine (50%), wound and soft tissue exudates (25%), and blood cultures (15%), mostly of nosocomial origin. Although P. penneri is easy to identify, it can be misidentified as P. vulgaris by automatic systems that do not include the indol test result in the identification process. This species has a characteristic susceptibility profile, essentially due to the production of the chromosomal inducible beta-lactamase HugA, which presents a high homology (86%) with CumA from P. vulgaris. HugA is inhibited by clavulanic acid and determines resistance to aminopenicillins and first- and second-generation cephalosporins, including cefuroxime, but does not affect cephamycins or carbapenems, and is inhibited by clavulanic acid. HugA is derepressed due to mutational processes in gene regulators, affecting the activity of cefotaxime and, to a much lesser extent, that of ceftazidime and aztreonam. This phenotype resembles the production of an extended spectrum beta-lactamase. Like other Proteus species, P. penneri is resistant to tetracyclines and should be considered resistant to nitrofurantoin.

Proteus penneri / Proteus penneri

Proteus penneri, anteriormente denominado Proteus vulgaris biogrupo 1, fue reconocido como especie nueva en 1982. Se asocia a procesos similares a los que producen Proteus mirabilis y Proteus vulgaris y comparte con ellos factores de patogenicidad. En muestras clínicas, se aísla esencialmente de orina (50%), exudados de piel y tejidos blandos (25%) y hemocultivos (15%), sobre todo en infección nosocomial. Su identificación no es problemática, aunque puede confundirse con P. vulgaris en los sistemas automáticos que no utilicen la prueba de indol en los procesos de identificación. Tiene un perfil de resistencia particular debido a la producción de la β-lactamasa cromosómica inducible HugA, con una elevada homología (86%) con CumA de P. vulgaris. HugA determina resistencia a aminopenicilinas y cefalosporinas de primera y segunda generación, incluyendo la cefuroxima, pero no afecta a las cefamicinas ni los carbapénemes, y se inhibe por el ácido clavulánico. La síntesis de HugA se desreprime debido a mutaciones en los genes reguladores, con lo que se afectan la actividad de la cefotaxima y, en mucha menor medida, la de la ceftazidima y el aztreonam. Este fenotipo puede confundirse con la producción de una β-lactamasa de espectro extendido. Al igual que otros Proteus penneri, es resistente a las tetraciclinas y debe considerarse resistente a la nitrofurantoína

Proteus penneri, formerly P. vulgaris biogroup 1, was recognized as a new species in 1982. This species is associated with clinical processes similar to those involving P. mirabilis and P. vulgaris and expresses similar pathogenic determinants. In clinical samples, P. penneri is mainly isolated from urine (50%), wound and soft tissue exudates (25%), and blood cultures (15%), mostly of nosocomial origin. Although P. penneri is easy to identify, it can be misidentified as P. vulgaris by automatic systems that do not include the indol test result in the identification process. This species has a characteristic susceptibility profile, essentially due to the production of the chromosomal inducible β-lactamase HugA, which presents a high homology (86%) with CumA from P. vulgaris. HugA is inhibited by clavulanic acid and determines resistance to aminopenicillins and first- and second-generation cephalosporins, including cefuroxime, but does not affect cephamycins or carbapenems, and is inhibited by clavulanic acid. HugA is derepressed due to mutational processes in gene regulators, affecting the activity of cefotaxime and, to a much lesser extent, that of ceftazidime and aztreonam. This phenotype resembles the production of an extended spectrum β-lactamase. Like other Proteusspecies, P. penneri is resistant to tetracyclines and should be considered resistant to nitrofurantoin

Structure of the O-polysaccharide and serological studies of the lipopolysaccharide of Proteus penneri 60 classified into a new Proteus serogroup O70.

An alkali-treated lipopolysaccharide of Proteus penneri strain 60 was studied by chemical analyses and 1H, 13C and 31P NMR spectroscopy, and the following structure of the linear pentasaccharide-phosphate repeating unit of the O-polysaccharide was established: 6)-alpha-D-Galp-(1-->3)-alpha-L-FucpNAc-(1-->3)-alpha-D-GlcpNAc-(1-->3)-beta-D-Quip4NAc-(1-->6)-alpha-D-Glcp-1-P-(O--> Rabbit polyclonal O-antiserum against P. penneri 60 reacted with both core and O-polysaccharide moieties of the homologous LPS. Based on the unique O-polysaccharide structure and serological data, we propose to classify P. penneri 60 into a new, separate Proteus serogroup O70. A weak cross-reactivity of P. penneri 60 O-antiserum with the lipopolysaccharide of Proteus vulgaris O8, O15 and O19 was observed and discussed in view of the chemical structures of the O-polysaccharides.

Characterization and serological classification of a collection of Proteus penneri clinical strains.

INTRODUCTION: Bacteria of the genus Proteus, which are a common cause of urinary tract infections, are divided into four species: P. mirabilis, P. vulgaris, P. penneri, and P. hauseri, and three unnamed genomospecies, Proteus 4, 5, and 6 (single-strain species P. myxofaciens was isolated from the gypsy moth). Establishing the serological classification of these species would aid in completing the classification scheme of the whole genus Proteus and in applying serological methods in diagnostic procedures and epidemiological investigations for these opportunistic pathogens. The aim of this research was a serological characterization and classification of 57 Proteus penneri clinical strains, isolated from patients from different countries all over the world, into Proteus O serogroups. MATERIAL/METHODS: Purified lipopolysaccharides (LPSs) extracted from 57 P. penneri strains were used as antigens in enzyme immunosorbent assay (EIA), SDS/PAGE, and Western blot techniques, and alkali treated LPSs in passive immunohemolysis test (PIH), inhibition of PIH, and absorption of rabbit polyclonal O-antisera. RESULTS: That result confirms the serological distinction of this species within the genus Proteus, and may have diagnostic significance. CONCLUSIONS: As a result of serological studies of LPSs extracted from the P. penneri strains, one new Proteus serogroup, represented by the P. penneri 97 strain, was established. Three further strains were classified into the Proteus serogroup O8, which had not contained any P. penneri strains before. All the remaining strains were classified into 11 already existing Proteus O serogroups. It is important to emphasize that 72% of studied strains were classified into serogroups that contain P. penneri strains only.