Association of hydroxamate siderophore (aerobactin) with Escherichia coli isolated from patients with bacteremia.

Clinical isolates of Escherichia coli were examined for the presence of hydroxamate siderophore (aerobactin). The incidence of aerobactin-positive strains of E. coli from the blood was greater than the incidence of these strains isolated from other sites.

Experimental pyelonephritis. The effect of T-cell deficiency on the course of hematogenous enterococcal pyelonephritis in the mouse.

The course of experimental hematogenous pyelonephritis due to Streptococcus faecalis was compared in athymic (nu/nu) mice and euthymic (nu/+) littermates. Up to 7 weeks following infection, there were no significant differences in renal microbial populations. At 63 and 107-131 days there was significant escalation of infection in nu/nu mice, while the nu/+ mice were decreasing their infections.

Treatment of staphylococcal pyelonephritis in rats with N-formimidoyl thienamycin.

The therapeutic efficacy of N-formimidoyl thienamycin alone or coadministered with MK0791, an inhibitor of renal dehydropeptidase-I, compared to methicillin in experimental pyelonephritis in rats was investigated. Pyelonephritis was produced with a methicillin-sensitive strain (2776) and a methicillin-resistant strain (Berman) of Staphylococcus aureus. N-formimidoyl thienamycin alone or coadministered with the inhibitor was significantly better than methicillin when treating methicillin-sensitive or methicillin-resistant infection.

Antibiotic prophylaxis against streptomycin-resistant and -susceptible Streptococcus faecalis endocarditis in rabbits.

This report describes the capacities of ampicillin, vancomycin, streptomycin, gentamicin, and combinations thereof to prevent endocarditis in rabbits challenged with either streptomycin-resistant (three strains) or streptomycin-susceptible (one strain) Streptococcus faecalis. Vancomycin (15 mg/kg) alone was effective in preventing infection with three of four strains, including two which were streptomycin resistant. Vancomycin (30 mg/kg) alone was effective against the other streptomycin-resistant strain.

Lack of significance of pili in experimental ascending Escherichia coli pyelonephritis.

The role of pili as a bacterial virulence factor has been studied. The model used was acute ascending Escherichia coli pyelonephritis in the mouse. Three strains of E.

Effect of iron on acute pyelonephritis and later chronic changes.

Administration of iron to rats exacerbated early inflammatory changes of pyelonephritis produced by intravenous inoculation of Escherichia coli. This effect was noted with four of eight strains of E. coli tested and was dependent on bacterial inoculum.

Variables in demonstrating methicillin tolerance in Staphylococcus aureus strains.

Certain technical considerations which affected the status of methicillin tolerance in Staphylococcus aureus strains were studied. Methods which consistently demonstrated tolerance or intolerance of a given strain were avoidance of inoculum splashing, use of stationary-phase inoculum, 24-h tube incubation, and minimization of antibiotic carry-over. These studies suggested a need for the establishment of a standardized reference for the determination of tolerance.

The role of antibiotic tolerance in the response to treatment of pyelonephritis due to Staphylococcus aureus in rats.

The effect of tolerance to methicillin on the response to treatment of hematogenous pyelonephritis due to Staphylococcus aureus was evaluated in rats. Tolerance was defined as a ratio of minimal bactericidal concentration to minimal inhibitory concentration of greater than or equal to 32. Rats that were infected with tolerant or nontolerant stains of S.

Rifampin, ampicillin, streptomycin, and their combinations in the treatment of enterococcal pyelonephritis in rats.

The activities of ampicillin, rifampin, streptomycin, and their combinations were evaluated in vitro against Streptococcus faecalis strain GK and in vivo in rats with an established pyelonephritis resulting from challenge with this same enterococcus. In vitro synergy was demonstrated between all combinations. Comparison of the log colony-forming units of S.

E. coli adherence to bladder epithelial cells of mice.

Adherence of E. coli to bladder cells was studied by mixing E. coli with cells scraped from the surface of the normal mouse bladder.

Effect of renal physicochemical milieu on stimulation of human lymphocytes by phytohemagglutinin.

The effect of changes in certain physicochemical parameters, analogous to those occurring in the kidney, on stimulation of normal human lymphocytes by phytohemagglutinin was studied. Increase in osmolality by sucrose or urea, and increases in concentration of sodium, potassium and calcium all significantly inhibited stimulation while magnesium did not. Lowering pH to 6.

Chemotactic activity of L-forms and mycoplasma.

L-forms of Streptococcus faecalis, Escherichia coli and Proteus mirabilis showed significantly less chemotactic activity for normal human leucocytes than did parent bacterial forms which were strongly chemotactic. Mycoplasma pneumoniae and Mycoplasma hominis did not demonstrate chemotactic activity.

Pyelonephritis. XIX. Immunization against enterococcal pyelonephritis.

A study has been done of immunization against Streptococcus faecalis pyelonephritis in the rat. Intravenous, subcutaneous, and bladder immunizations were tested with intravenous and retrograde challenge. Logarithmic and stationary growth phase organisms were used separately for both immunization and challenge.

Klebsiella L-forms: effect of growth as L-form on virulence of reverted Klebsiella pneumoniae.

A strain of Klebsiella pneumoniae virulent for mice was serially passaged in vitro as a penicillin-induced L-form. Periodically, the L-form was reverted to the bacterial form by removal of penicillin, and the revertant was tested for virulence. Virulence was gradually reduced, and after 109 passages the revertant was totally avirulent.

Arthritis in mice due to infection with Mycoplasma pulmonis. II. Serological and histological features.

Histological and serological data were obtained from a group of 160 mice given intravenous inoculations of 3.5 X 10(7) colony-forming units of Mycoplasma pulmonis and studied for 46 weeks. The basic pathology was that of an initial acute inflammatory response within the joint and periarticular tissues, slowly changing to a chronic inflammatory response seen predominantly in subsynovial areas with marked synovial proliferation.

Urinary-tract infection: localisation and virulence of Escherichia coli.

Virulence of 15 strains of Escherichia coli from the human upper urinary tract was compared with that of 16 strains from the lower urinary tract, using an ascending infection in the mouse. No significant difference was found. There was no significant difference in frequency of K antigen and ability to ferment dulcitol between 32 lower strains and 31 upper strains.