Effect of Bacteroides fragilis on mortality induced by Escherichia coli in an experimental infection treated with cefotaxime, aztreonam or gentamicin.

The possibility that beta-lactamase-producing strains of Bacteroides fragilis can protect Escherichia coli from cefotaxime was studied in an in-vivo model of peritoneal infection in rats. The protective effect of cefotaxime, aztreonam and gentamicin in peritonitis induced by E. coli alone or combined with B.

Purification and properties of five different forms of human procarboxypeptidases.

Three different procarboxypeptidases A and two different procarboxypeptidases B have been isolated for the first time, in a pure and native state, from human pancreatic extracts. These proteins were purified in one or two quick steps by anion-exchange HPLC. All these forms have been biochemically characterized.

In-vitro activity of amoxycillin/clavulanic acid and five other oral antibiotics against clinical isolates of Haemophilus influenzae and Branhamella catarrhalis.

The in-vitro activity of amoxycillin/clavulanic acid, amoxycillin, erythromycin, doxycycline, chloramphenicol and cephalexin against 183 clinical isolates of Haemophilus influenzae and 61 of Branhamella catarrhalis was determined. Amoxycillin/clavulanic acid showed the greatest activity against H. influenzae.

Skin colonization by Corynebacterium groups D2 and JK in hospitalized patients.

To determine the prevalence of Corynebacterium group D2 and JK organisms on the skin of different types of patients, 200 hospitalized subjects, half of them admitted to a university hospital and the others in a chronic care institution, were surveyed. Samples were taken from the axilla, groin, and abdominal wall. Corynebacterium group D2 and JK organisms were isolated from at least one of the three skin sites in both groups of patients.

Aortic endocarditis caused by gentamicin-resistant Enterococcus faecalis.

A case is reported of a patient who developed aortic endocarditis after protracted hospitalization during which time the patient received multiple courses of aminoglycoside and cephalosporin therapy. The infecting organism, an Enterococcus faecalis strain, was resistant to gentamicin and to the combination of ampicillin with gentamicin. Valve replacement was performed after four weeks of therapy with ampicillin, and enterococci were isolated from cardiac vegetations.

In vivo significance of the inoculum effect of antibiotics on Escherichia coli.

The minimum dosage of antibiotics which reduced mortality in rats intraperitoneally inoculated with an Escherichia coli isolate was determined. Low mortality rates (0-10%) were obtained when antibiotics with minimal or no inoculum effect (cefoxitin, cefmetazole and gentamicin) were administered to yield serum levels 3 to 20 times the MIC, while antibiotics with a pronounced inoculum effect (cefotaxime and aztreonam) had to be administered to yield serum levels 200 to 1,000 times the MIC determined with a standard (low) inoculum. Thus, it seems that the inoculum effect observed in vitro with some antibiotics for Escherichia coli may have clinical significance.

Infections caused by antibiotic-resistant Corynebacterium group D2.

A coryneform bacteria known as Corynebacterium group D2 pending definitive taxonomic classification, has emerged as a human pathogen. Although first described 16 years ago, the organism has only recently been implicated in clinical infections. It differs from all previously recognized species of Corynebacterium, and in common with Corynebacterium jeikeium exhibits a broad spectrum of antimicrobial resistance, being sensitive to only vancomycin, teicoplanin and some quinolones.

Q fever endocarditis on porcine bioprosthetic valves. Clinicopathologic features and microbiologic findings in three patients treated with doxycycline, cotrimoxazole, and valve replacement.

Three patients developed Q fever endocarditis on porcine bioprosthetic valves. They had a subacute or chronic course with nonspecific symptoms, enlargement of the liver and spleen, and cardiac failure due to destruction of the cusps, without disruption of the valve ring. High-phase I-specific IgG and IgA antibody titers against Coxiella burnetii were found.

Susceptibility of urinary isolates of Corynebacterium group D2 to fifteen antimicrobials and acetohydroxamic acid.

The susceptibility in vitro of 28 Corynebacterium group D2 strains, mainly isolated from urine, to fifteen antimicrobial agents and acetohydroxamic acid (AHA) was determined at two pH values. The bactericidal activity of four antimicrobials and AHA was studied in three reference strains in broth at two pHs and with two inoculum sizes. The activity of norfloxacin and AHA, against one selected strain, in broth and human urine, was also determined.

Pulmonary infection by Mycobacterium gordonae in an immunocompromised patient.

Mycobacterium gordonae, a scotochromogenic organism, is considered a saprophyte and isolation of this organism in sputum cultures is not generally considered clinically significant. We report the case of 70-yr-old man with Hodgkin's disease and pulmonary infection caused by Mycobacterium gordonae. The clinical and radiographic findings in this case and the course are outlined.

Bacteriuria with a multiply resistant species of Corynebacterium (Corynebacterium group D2): an unnoticed cause of urinary tract infection.

We studied the records of 43 patients with significant bacteriuria caused by Corynebacterium group D2. All suffered from underlying diseases, and 54% were immunosuppressed. The predisposing factors were urologic procedures (100%), previous use of antibiotics (90%), age greater than 65 years (65%), and previous urinary tract infections (UTI;60%).

Activity of nine antimicrobial agents against Corynebacterium group D2 strains isolated from clinical specimens and skin.

The in vitro activities of nine antimicrobial agents against Corynebacterium group D2 strains isolated from clinical specimens and from healthy skin of hospitalized patients were studied. Ciprofloxacin, ofloxacin, norfloxacin, vancomycin, and teicoplanin were very active against these microorganisms. There were no significant differences in susceptibility between clinical and colonizing isolates.

Struvite crystal formation by Corynebacterium group D2 in human urine and its prevention by acetohydroxamic acid.

After 24 h incubation of human urine experimentally inoculated with Corynebacterium group D2, struvite crystals appeared with an increase in pH and ammonium concentration as well as a decrease in the urea concentration. These changes were prevented by the addition of variable concentrations of acetohydroxamic acid. From these results it seems that the prevention of such crystal formation by Corynebacterium group D2 could be due to the inhibition of its urease activity besides acetohydroxamic acid having a significant antimicrobial activity, principally when tested in human urine.

Primary structure of the activation segment of procarboxypeptidase A from porcine pancreas.

The complete primary structure of the activation segment of monomeric procarboxypeptidase A from porcine pancreas has been determined by automated and manual Edman-like degradation methods performed on its fragments generated by enzymatic cleavage. The polypeptide consists of 94 residues, with a molecular mass of 10,768, and presents a high proportion of acidic and hydrophobic residues and a proline-rich region in the center of the molecule. Comparison of this sequence with the already reported equivalent sequence deduced from rat procarboxypeptidase A cDNA reveals a very high degree of homology between the two propeptides (up to a 81% of identities), which is even higher in certain large zones of the molecule.

Bacteroides fragilis meningitis successfully treated with metronidazole after a previous failure with thiamphenicol.

A case of pyogenic meningitis caused by Bacteroides fragilis in a 72-year-old woman is reported. Although the isolate was susceptible to thiamphenicol, the patient did not respond to this drug. Metronidazole, which showed high bactericidal activity, was administered and achieved sterilization of the cerebrospinal fluid and complete clinical response.