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Fulminant primary Pseudomonas aeruginosa pneumonia and septicaemia in previously well adults.

We report two cases of primary, community acquired, Pseudomonas aeruginosa pneumonia, occurring in previously well adults without any recognisable environmental risk factors. Both patients died within 36 h of the onset of symptoms, despite broad spectrum antibiotics and aggressive supportive care. In neither case was the diagnosis considered in life and neither patient received adequate anti-pseudomonas therapy. Heightened awareness of this rare, fulminant, variant of primary Pseudomonas pneumonia is required if specific anti-pseudomonas therapy is to have any impact on outcome.

Adult↗

Epidemiology of community-acquired Pseudomonas aeruginosa infections in children.

The epidemiology of community-acquired Pseudomonas aeruginosa infections in children during a one-year period (January through December 1993) was evaluated. A total of 6,859 clinical samples, each one representing a separate individual with suspected infection, were cultured. Pseudomonas aeruginosa was isolated from 218 children with various infections occurring in the following order of frequency: chronic suppurative otitis media, 76.3%; appendicitis/peritonitis, 10.3%; osteomyelitis, 8.9%; skin or soft tissue infection, 6.3%; acute conjunctivitis, 3.0%; and urinary tract infection, 0.1%. A variety of O serogroups were identified: O1 (15.2%), O6 (14.7%), O11 (12.4%), O10 (11.5%), O3 (10.6%), O5 (5.1%), and O9 (4.6%). Other serogroups and nontypable strains were recovered at a frequency of 11.2% and 14.7%, respectively. Nontypable strains predominated in chronic otitis media (18.9%), while serogroups O1 (18.3%), O6 (17.5%), and O11 (17.5%) were recovered most frequently among the typable isolates. Susceptibility of Pseudomonas aeruginosa to antipseudomonadal agents was extremely high. The rate of susceptibility to ceftazidime was 99.6%, to azlocillin 98.6%, to piperacillin 98.2%, to aztreonam 97.3%, to gentamicin and netilmicin 97.7%, and to ciprofloxacin 99.1%. All isolates were susceptible to tobramycin, imipenem, and amikacin. The results might suggest that community-acquired Pseudomonas aeruginosa infections in children can be treated successfully with any antipseudomonadal antibiotic.

Age Factors↗

Combination effect of meropenem with aminoglycosides and teicoplanin on Pseudomonas and enterococci.

The in vitro activity of meropenem, a new carbapenem, and the combination effect with netilmicin, tobramycin, gentamicin, and teicoplanin against Pseudomonas spp. and enterococci was studied. Meropenem showed very good in vitro activity against Pseudomonas aeruginosa (MIC90 2 mg/l) and good to moderate activity against Pseudomonas putida (MIC90 4 mg/l) and Enterococcus faecalis (MIC90 8 mg/l). Aminoglycosides were highly active against P. putida (MIC90 0.5 mg/l), but showed only moderate activity against P. aeruginosa. The synergistic effect of meropenem was shown in combination with teicoplanin against E. faecalis (40%). No Pseudomonas strains were inhibited by the synergistic effect of meropenem with aminoglycosides. No antagonism occurred with any of the combinations.

Aminoglycosides↗

Genome fingerprinting by pulsed-field gel electrophoresis and ribotyping to differentiate Pseudomonas aeruginosa serotype O11 strains.

The performance of ribotyping and pulsed-field gel electrophoresis was compared in the differentiation of a collection of 44 Pseudomonas aeruginosa serotype O11 strains isolated in seven hospitals in Singapore. Digestion of genomic DNA by EcoRI and SacI followed by Southern hybridization with the Pseudomonas aeruginosa 16S and 23S rRNA gene revealed seven distinct ribotypes. Ribotyping using a combination of both enzymes revealed 11 ribotypes. In contrast, electrophoretic analysis differentiated 41 different strain types among the 44 clinical isolates using either SpeI or DraI. Pulsed-field gel electrophoresis demonstrated greater sensitivity than ribotyping in the differentiation of Pseudomonas aeruginosa strains of the same ribotype and could thus be used alone in epidemiological investigations of hospital outbreaks of Pseudomonas aeruginosa serotype O11 infection.

DNA Fingerprinting↗

Ciprofloxacin for respiratory tract infection with Pseudomonas aeruginosa.

Thirty one patients were treated with oral ciprofloxacin for bronchitis with Pseudomonas aeruginosa. Twenty eight patients had permanent and 14 transient risk factors. Nine patients had a hospital infection with Pseudomonas aeruginosa. Sixteen patients were cured, complete or partial, but Pseudomonas aeruginosa persisted or recurred in 19 patients. Patients with hospital infection did better than other patients. There was a significant decrease in in vitro susceptibility of persisting strains of Pseudomonas aeruginosa to ciprofloxacin and a tendency of recovery of susceptibility for the drug after treatment.

Adolescent↗

Acetylcholinesterase from rat red cells and cholinesterase of Pseudomonas aeruginosa: different types of inhibition by atropine.

The inhibition by atropine of cholinesterase from Pseudomonas aeruginosa has been studied in parallel with the membrane bound acetylcholinesterase from rat red cells. Acetylcholinesterase of rat red cells, like other animal cholinesterases, was competitively inhibited while the cholinesterase from Pseudomonas aeruginosa was partially non competitively inhibited by atropine. These results clearly indicated a different behavior of cholinesterase from Pseudomonas aeruginosa in comparison with the enzyme of Pseudomonas fluorescens and other animal cholinesterases.

Acetylcholinesterase↗

Pseudomonas colonization in cystic fibrosis: lack of correlation with secretion of ABO blood group antigens.

In cystic fibrosis, a majority of patients develop persistent lifelong respiratory tract colonisation with pseudomonas aeruginosa while a minority do not appear to become colonised. There is some evidence that non-secretion of ABO Blood Group antigens into body secretions is a marker for susceptibility to certain gram negative infections. Therefore, we studied 47 adult patients with cystic fibrosis to identify an association, if any, between secretor status and the presence or absence of pseudomonas aeruginosa in their sputum. Overall, we found no difference between the prevalence of non-secretors in our patient group and in the normal population. Furthermore, there was no association between secretor status and presence or absence of pseudomonas aeruginosa in sputum. We conclude that secretor status is unlikely to play a major role in susceptibility to pseudomonas aeruginosa infection in patients with cystic fibrosis.

ABO Blood-Group System↗

Pyoverdines: pigments, siderophores and potential taxonomic markers of fluorescent Pseudomonas species.

Pyoverdine, the yellow-green, water-soluble, fluorescent pigment of the fluorescent Pseudomonas species, is a powerful iron(III) scavenger and an efficient iron(III) transporter. As a fluorescent pigment, it represents a ready marker for bacterial differentiation and, as a siderophore, it plays an important physiological function in satisfying the absolute iron requirement of these strictly aerobic bacteria. Close to 40 structurally different pyoverdines have been identified to date, each characterized by a different peptidic part of the molecule and by a very narrow specificity as an iron transporter for Pseudomonas species, usually restricted to the producer strain or to strains producing an identical compound. Cross-reactivity does occur, however, for pyoverdines exhibiting partial identity at the peptide chain level, suggesting some information on the receptor-recognition site of the molecule. With the recent description of an operonic cluster of four genes involved in the synthesis of the chromophoric part of the molecule, a total of seven pyoverdine biosynthetic genes have been identified so far in Pseudomonas aeruginosa PAO1. Although the precise function of the gene products needs further clarification, a biosynthetic pathway based on a multienzyme thiotemplate mechanism allowing a step-by-step synthesis of the whole chromopeptide molecule can be postulated. A promising future is expected from recent developments which indicate that pyoverdines might be considered as potent and easy-to-handle taxonomic markers for the fluorescent species of the genus Pseudomonas.

Bacterial Typing Techniques↗

Modeling of growth kinetics for Pseudomonas spp. during benzene degradation.

A modeling study was conducted on growth kinetics of three different strains of Pseudomonas spp. (Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas putida) during benzene degradation to determine optimum substrate concentrations for most efficient biodegradation. Batch tests were performed for eight different initial substrate concentrations to observe cell growth and associated substrate degradation using benzene-adapted cells. Kinetic parameters of both inhibitory (Haldane-Andrews, Aiba-Edwards) and noninhibitory (Monod) models were fitted to the relationship between specific growth rate and substrate concentration obtained from the growth curves. Results showed that half-saturation constant of P. fluorescens was the highest among the three strains, indicating that this strain could grow well at high concentration, while P. putida could grow best at low concentration. The inhibition constant of P. aeruginosa was the highest, implying that it could tolerate high benzene concentration and therefore could grow at a wider concentration range. Estimated specific growth rate of P. putida was lower, but half-saturation constant was higher than those from literature study due to high substrate concentration range used in this study. These two kinetic parameters resulted in substantial difference between Monod- and Haldane-type models, indicating that distinction should be made in applying those models.

Benzene↗

Biotransformation of eugenol to vanillin by a mutant of Pseudomonas sp. strain HR199 constructed by disruption of the vanillin dehydrogenase (vdh) gene.

The catabolism of eugenol in Pseudomonas sp. strain HR199 (DSM7063) proceeds via coniferyl alcohol, coniferyl aldehyde, ferulic acid, vanillin, vanillate and protocatechuate, which is further degraded by the ortho-cleavage pathway. The vanillin dehydrogenase of Pseudomonas sp. strain HR199, which catalyses the NAD(+)-dependent oxidation of vanillin to vanillate, was inactivated by the insertion of omega elements into the vdh gene, which was characterized recently. Omega elements conferring resistance against kanamycin (omega Km) or gentamycin (omega Gm) were constructed by polymerase chain reaction amplification of the aminoglycoside 3'-O-phosphotransferase gene and the gentamycin-3-acetyltransferase gene, using the plasmids pSUP5011 and pBBR1MCS-5 respectively as template DNA. A 211-bp BssHII fragment of the vdh gene was substituted by omega Km or omega Gm, and the functional vdh gene was replaced by vdh omega Km or vdh omega Gm in Pseudomonas sp. strain HR199 by homologous recombination. Cells of the mutant Pseudomonas sp. strain HR vdh omega Km, pregrown on gluconate, accumulated up to 2.9 mM vanillin during incubation in mineral medium with 6.5 mM eugenol. As a result of another vanillin dehydrogenase activity (VDH-II), the accumulated vanillin was further degraded, when coniferyl aldehyde was exhausted from the medium. Characterization of the purified VDH-II revealed the identify of this enzyme with the recently characterized coniferyl-aldehyde dehydrogenase.

Aldehyde Oxidoreductases↗

Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyalkanoates) by recombinant bacteria expressing the PHA synthase gene phaC1 from Pseudomonas sp. 61-3.

Pseudomonas sp. 61-3 accumulated a blend of poly(3-hydroxybutyrate) [P(3HB)] homopolymer and a random copolymer consisting of 3-hydroxyalkanoate (3HA) units of 4-12 carbon atoms. The genes encoding beta-ketothiolase (PhbA(Re)) and NADPH-dependent acetoacetyl-CoA reductase (PhbB(Re)) from Ralstonia eutropha were expressed under the control of promoters for Pseudomonas sp. 61-3 pha locus or R. eutropha phb operon together with phaC1(Ps) gene (PHA synthase 1 gene) from Pseudomonas sp. 61-3 in PHA-negative mutants P. putida GPp104 and R. eutropha PHB(-4) to produce copolyesters [P(3HB-co-3HA)] consisting of 3HB and medium-chain-length 3HA units of 6-12 carbon atoms. The introduction of the three genes into GPp104 strain conferred the ability to synthesize P(3HB-co-3HA) with relatively high 3HB compositions (up to 49 mol%) from gluconate and alkanoates, although 3HB units were not incorporated at all or at a very low fraction (3 mol%) into copolyesters by the strain carrying phaC1Ps gene only. In addition, recombinant strains of R. eutropha PHB(-4) produced P(3HB-co-3HA) with higher 3HB fractions from alkanoates and plant oils than those from recombinant GPp104 strains. One of the recombinant strains, R. eutropha PHB(-4)/ pJKSc46-pha, in which all the genes introduced were expressed under the control of the native promoter for Pseudomonas sp. 61-3 pha locus, accumulated P(3HB-co-3HA) copolyester with a very high 3HB fraction (85 mol%) from palm oil. The nuclear magnetic resonance analyses showed that the copolyesters obtained here were random copolymers of 3HB and 3HA units.

Acyltransferases↗

Characterization of the eugenol hydroxylase genes (ehyA/ehyB) from the new eugenol-degrading Pseudomonas sp. strain OPS1.

During the screening for bacteria capable of converting eugenol to vanillin, strain OPS1 was isolated, which was identified as a new Pseudomonas species by 16 s rDNA sequence analysis. When this bacterium was grown on eugenol, the intermediates, coniferyl alcohol, ferulic acid, vanillic acid, and protocatechuic acid, were identified in the culture supernatant. The genes encoding the eugenol hydroxylase (ehyA, ehyB), which catalyzes the first step of this biotransformation, were identified in a genomic library of Pseudomonas sp. strain OPS1 by complementation of the eugenol-negative mutant SK6165 of Pseudomonas sp. strain HR199. EhyA and EhyB exhibited 57% and 85% amino acid identity to the eugenol hydroxylase subunits of Pseudomonas sp. strain HR199 and up to 34% and 54% identity to the corresponding subunits of p-cresol methylhydroxylase from P. putida. Moreover, the amino-terminal sequences of the alpha- and beta-subunits reported recently for an eugenol dehydrogenase of P fluorescens E118 corresponded well with the appropriate regions of EhyA and EhyB. Downstream of ehyB, an open reading frame was identified, whose deduced amino acid sequence exhibited up to 71% identity to azurins, representing most probably the gene (azu) of the physiological electron acceptor of the eugenol hydroxylase. The eugenol hydroxylase genes were amplified by PCR, cloned, and functionally expressed in Escherichia coli.

Bacterial Proteins↗

Physiological characterization and genetic engineering of Pseudomonas corrugata for medium-chain-length polyhydroxyalkanoates synthesis from triacylglycerols.

Pseudomonas belonging to the rRNA-DNA homology group I produce medium-chain-length (mcl)-polyhydroxyalkanoates (PHA). We show that P. corrugata, a member of this group, accumulates 0.5-1.0 g of mcl-PHA/L of culture when grown on glucose (Gl) or oleic acid (Ol). The predominant monomers of Gl-PHA and Ol-PHA are beta-hydroxydecanoate and beta-hydroxyoctanoate, respectively. The molecular masses and polydispersity of P. corrugata PHAs are higher than those typically found with other Pseudomonas. We electrotransformed P. corrugata with a plasmid pCN51lip-1 carrying Pseudomonas lipase genes to generate strain III111-1. The recombinant strain grew on intact triacylglycerols (TAGs) to 1.9-2.7 g of cell-dry-weight/L of culture. The yields and the predominant repeat-units of PHAs obtained from the lard- and tallow-grown III111-1 were similar to those of Ol-PHA from wild-type cells. In contrast to other Pseudomonas species, P. corrugata III111-1 grown on TAGs at temperatures up to 36 degrees C was not significantly affected with regard to cell yields, amounts of PHA produced, and the repeat unit compositions of the polymer.

Biopolymers↗

Serious Pseudomonas infections associated with endoscopic retrograde cholangiopancreatography.

After observing a single case of Pseudomonas aeruginosa bacteremia following endoscopic retrograde cholangiopancreatography (ERCP), six other P. aeruginosa infections that were temporally related to ERCP were retrospectively found over one year (August 1985 through July 1986) at LDS Hospital. In all seven patients, infection developed within five days after an ERCP. Five patients had bacteremia and two had cholangitis. All five of the Pseudomonas isolates available for testing were serotype 010. Cultures from the ERCP endoscope and several other endoscopes also yielded P. aeruginosa serotype 10, as did environmental cultures from equipment used to clean endoscopes. Among 167 ERCPs performed during the outbreak period, no other patient acquired P. aeruginosa infection. Each of the patients in the outbreak received the first scheduled ERCP of the day. The mean duration between the cleaning of the ERCP endoscope and its subsequent use was significantly longer in cases than in matched controls, a factor that may have permitted contaminating organisms to achieve high inocula in the inadequately cleaned endoscope. Epidemic control measures included improved disinfection of endoscopes, ongoing surveillance, and appropriate antimicrobial prophylaxis. This experience suggests that exogenous infection with Pseudomonas is associated with ERCP, that protracted and insidious outbreaks may occur, and that the occurrence of even a single case of Pseudomonas infection after ERCP should stimulate an epidemiologic investigation.

Cholangiopancreatography, Endoscopic Retrograde↗

Immunological relatedness of histidine ammonia-lyases from some species of Pseudomonas: taxonomic implication.

1. Histidine ammonia-lyases (histidase EC 4.3.1.3) from Pseudomonas testosteroni NCIB 10808 and Pseudomonas putida NCIB 10807 were purified and specific antibody was raised to each separately in a rabbit. 2. Immunological cross-reactions of each antibody to histidine ammonia-lyases from various species of Pseudomonas were examined by the enzyme inhibition test. 3. The immunological data obtained suggest that these Pseudomonas species can be classified into three groups. These cross-reactions tend to indicate a certain degree of homology within species in a group but not between groups.

Ammonia-Lyases↗

Oxidation of C1-compounds in Pseudomonas C.

Extracts of Pseudomonas C grown on methanol as a sole carbon and energy source contain a methanol dehydrogenase activity which can be coupled to phenazine methosulfate. This enzyme catalyzes two reactions namely the conversion of methanol to formaldehyde (phenazine methosulfate coupled) and the oxidation of formaldehyde to formate (2,6-dichloroindophenol-coupled). Activities of glutathione-dependent formaldehyde dehydrogenase (NAD+) and formate dehydrogenase (NAD+) were also detected in the extracts. The addition of D-ribulose 5-phosphate to the reaction mixtures caused a marked increase in the formaldehyde-dependent reduction of NAD+ or NADP+. In addition, the oxidation of [14C]formaldehyde to CO2, by extracts of Pseudomonas C, increased when D-ribulose 5-phosphate was present in the assay mixtures. The amount of radioactivity found in CO2, was 6;8-times higher when extracts of methanol-grown Pseudomonas C were incubated for a short period of time with [1-14C]glucose 6-phosphate than with [U-14C]glucose 6-phosphate. These data, and the presence of high specific activities of hexulose phosphate synthase, phosphoglucoisomerase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase indicate that in methanol-grown Pseudomonas C, formaldehyde carbon is oxidized to CO2 both via a cyclic pathway which includes the enzymes mentioned and via formate as an oxidation intermediate, with the former predominant.

Cytochrome c Group↗

The Pseudomonas putida ML2 plasmid-encoded genes for benzene dioxygenase are unusual in codon usage and low in G+C content.

Benzene dioxygenase, catalyzing the oxidation of benzene to cis-1,2-dihydroxy-cyclohexa-3,5-diene, comprises four polypeptides that are encoded by plasmid pHMT112 of Pseudomonas putida ML2. In this study, the nucleotide (nt) sequences of four genes encoding this enzyme (bedC1C2BA) were determined, and the amino acid (aa) sequences were deduced. The sequence showed significant homology with the chromosomally encoded benzene dioxygenase and toluene dioxygenase genes (73-77% for nt and 83-99% for aa), but not the plasmid-encoded naphthalene dioxygenase genes (20-26% for nt and 32-36% for aa). A conserved motif (Cys-Xaa-His-15-to-17 aa-Cys-Xaa2-His, where Xaa is any aa), proposed to bind the Rieske-type [2Fe-2S] cluster, was identified in the deduced aa sequence of the iron-sulfur proteins. Three regions were also identified in the flavoprotein which are likely to be involved in FAD and NAD+ binding. The gene order of bedC1C2BA is consistent with most ring-hydroxylating dioxygenases isolated from Pseudomonas. However, the G+C content of 47% is in contrast to the high G+C content of the Pseudomonas chromosome (63%) and other Pseudomonas plasmids (57%), and with its unique codon usage preference this suggests that bedC1C2BA originated from a host derived from a different genus.

Amino Acid Sequence↗

Cloning and expression of a Pseudomonas 3 alpha-hydroxysteroid dehydrogenase-encoding gene in Escherichia coli.

A bacterial strain, B-0831, which produced 3 alpha-hydroxysteroid dehydrogenase (3 alpha HSD) was isolated and identified as belonging to the genus, Pseudomonas. Molecular weights of the purified 3 alpha HSD, determined by SDS-PAGE and by chromatography on Sephacryl S-200, were about 25 and 50 kDa, respectively. A genomic library of Pseudomonas sp. B-0831, prepared in the plasmid vector pACYC184, was screened with probes based on the amino acid (aa) sequence of the protein to obtain the plasmid, p3 alpha HSD1, identified by hybridization with the probes, that contained a 2.4-kb insert from Pseudomonas DNA. When the 1.4-kb SphI fragment of p3 alpha HSD1 was inserted into the vector, pUC118, and introduced into Escherichia coli DH1 under the control of lacZ promoter in the vector, the transformants produced 200-fold more 3 alpha HSD intracellularly than Pseudomonas sp. B-0831. Sequence analysis of the 3 alpha HSD gene revealed that an ORF encoding 3 alpha HSD consists of 254 aa, with a calculated M(r) of 25,761, suggesting that the enzyme consists of homodimer subunits.

3-Hydroxysteroid Dehydrogenases↗