Purification and characterisation of elastase from Staphylococcus epidermidis.

An elastase of Staphylococcus epidermidis was purified by ion exchange chromatography on CM-Sepharose and characterised. Its M(r) is c. 21 kDa, its optimal temperature for activity is 42 degrees C and the pH optimum is 6.8. The enzyme is activated by cysteine and other SH-donators and inhibited by L-trans-epoxy-succinylleucylamido-(4-guanidino)butane (E64), an inhibitor of cysteine proteases, but not by 3,4-dichloroisocoumarin (3,4-DCI), an inhibitor of serine proteases. This finding suggests that the elastase of S. epidermidis is a cysteine protease. Because S. epidermidis elastase degrades human sIgA, IgM, serum albumin, fibrinogen, and fibronectin, this enzyme may be regarded as a virulence factor.     

Identification and characterization of a surface-associated protein (Ssp) of Staphylococcus saprophyticus.

A 95-kDa protein was isolated from Staphylococcus saprophyticus 7108 grown on dialysis membranes placed on the surface of brain heart infusion agar. Strain CCM883 did not produce this protein. Ultrathin sections revealed the presence of very thin, tuftlike, 50- to 75-nm-long structures on the surface of strain 7108, whereas strain CCM883 was comparably smooth. The surface material could be removed by digestion with proteinase K, suggesting that the surface structures contain protein. High-resolution scanning electron microscopy showed a thick layer of surface material on strain 7108, whereas strain CCM883 appeared smooth. The 95-kDa protein was purified by Sephacryl S-300 chromatography, and an antiserum was raised in rabbits. This antiserum was used in immunogold labeling experiments, which showed that the protein is associated with the surface structures. Our experiments thus demonstrate the presence of a fibrillar protein on the surface of S. saprophyticus (Ssp for S. saprophyticus surface-associated protein).     

Fungaemia due to Candida pelliculosa in a case of acute pancreatitis.

We describe a case of fungaemia due to Candida pelliculosa (teleomorph: Hansenula anomala) in an otherwise non-immunocompromised patient with acute necrotizing pancreatitis of unknown origin. This species of Candida should be added to the list of pathogenic fungi which are increasingly important not only in patients with underlying immunosuppressive disease but also in patients with, for instance, severe surgical illness.     

Contribution of cloned virulence factors from uropathogenic Escherichia coli strains to nephropathogenicity in an experimental rat pyelonephritis model.

Escherichia coli 536 (O6:K15:H31), which was isolated from a case of urinary tract infection, determines high nephropathogenicity in a rat pyelonephritis system as measured by renal bacterial counts 7 days after infection. The loss of S fimbrial adhesin formation (Sfa-) (mannose-resistant hemagglutination [Mrh-] and fimbria production [Fim-]), serum resistance (Sre-), and hemolysin production (Hly-) in the mutant 536-21 led to a dramatic reduction of bacterial counts from almost 10(5) to only 40 cells per g of kidney. The reintroduction of the cloned S fimbrial adhesin determinant (sfa) increases the virulence of the avirulent mutant strain by a factor of 20; almost the same effect was observed after restoration of serum resistance by integration of an sfa+ recombinant cosmid into the chromosome. Additional reintroduction of the Hly+ phenotype by transformation of two hly determinants increased the virulence of the strains. Hemolysin production determined increased renal elimination of leukocytes and erythrocytes. Thus all three determinants investigated, S fimbriae, serum resistance, and hemolysin, contribute to the multifactorial phenomenon of E. coli nephropathogenicity.     

Genetically engineered S and F1C fimbriae differ in their contribution to adherence of Escherichia coli to cultured renal tubular cells.

Escherichia coli K-12 strains producing S-fimbrial adhesins, F1C fimbriae, and mutagenized fimbriae were tested in a binding assay with a renal tubular cell line. S-fimbrial adhesins and F1C fimbriae mediated binding to tubular cells. The SfaA, SfaG, and SfaS subunits of S fimbriae contributed to attachment. Site-specific mutations in the sfaS gene reduced binding. The inhibition profile of F1C fimbriae resembled that of S fimbriae.     

Growth of Chlamydia pneumoniae induces cytokine production and expression of CD14 in a human monocytic cell line.

Chlamydia pneumoniae was able to survive and to multiply in the human monocytic cell line Mono Mac 6. Growth of C. pneumoniae induced production of tumor necrosis factor alpha, interleukin 1beta, and interleukin 6, as well as up-regulation of the CD14 molecule in a time-dependent manner. Infection of monocytic cells and a proinflammatory cytokine response may be important in C. pneumoniae pathogenesis.     

Antimicrobial resistance of Escherichia coli and therapeutic implications

Widespread antibiotic resistance has been recognized in Escherichia coli isolates from human, animal and environmental sources. Although prevalence rates for resistant E. coli strains are significantly distinct for various populations and environments, the impact of resistance to antimicrobial drugs is ubiquitous. This article provides information about the epidemiology, mechanisms and molecular principles of resistance, shows consequences for the antiinfective treatment of selected infections and describes measures to control the spread of antibiotic-resistant E. coli.