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Biomedical subjects

R Fernández-Roblas

Publications and source records attributed to R Fernández-Roblas.

17 recordsLinked to original sources
PubMed1991

Comparative in vitro activity of the new glycopeptide SK&F 104662 against problematic gram-positive bacteria.

The in vitro activity of the new glycopeptide antibiotic SK&F 104662 against problematic gram-positive microorganisms was determined using the agar dilution technique. For comparison, ampicillin, oxacillin, vancomycin, erythromycin and gentamicin were tested. SK&F 104662 was found to have high activity against Staphylococcus aureus, coagulase-negative staphylococci (both methicillin sensitive and resistant strains), Enterococcus faecalis, Enterococcus faecium, Listeria monocytogenes, Corynebacterium jeikeium and Corynebacterium group D2. All of 254 isolates, except one vancomycin-resistant strain of Enterococcus faecium, were inhibited by 2 mg/l of SK&F 104662; this compound may thus be potentially useful in the treatment of infections with the above-mentioned gram-positive pathogens.

Anti-Bacterial Agents↗
PubMed1988

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. The microorganisms is mainly involved in urinary tract infections, and its strong urease activity seems to play an important role in its pathogenicity. Corynebacterium jeikeium and group D2 are very different from the clinical and microbiological point of view. Corynebacterium group D2, like other coryneform bacteria, may be isolated from healthy skin in hospitalized patients, mainly females, while Corynebacterium jeikeium is more prevalent in males. Microbiologists should be aware that such a slow-growing microorganism may be responsible for clinical infections and should not be overlooked in routine cultures of clinical specimens.

Anti-Bacterial Agents↗
PubMed1988

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.

Animals↗
PubMed1988

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. All isolates of B. catarrhalis were susceptible to amoxycillin/clavulanic acid, chloramphenicol, cephalexin and doxycycline.

Amoxicillin↗
PubMed1988

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. Only five patients harbored groups D2 and JK at the same time but a different skin sites. The rate of colonization by group D2 organisms was higher in females (43.3%) than in males (17.7%); on the contrary, group JK organisms were isolated more frequently from males (32.1%) than from females (13.5%). All these differences were statistically significant. Corynebacterium group D2 and JK organisms are widely distributed on the skin of hospitalized patients, and the prevalence is sex related.

Abdomen↗
PubMed1987

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. Vancomycin, ofloxacin and norfloxacin were the most active agents tested. Norfloxacin acted bactericidally in broth and in human urine but was not synergic with AHA.

Anti-Bacterial Agents↗
PubMed1987

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.

Anti-Bacterial Agents↗
PubMed1987

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. These effects were dose-related.

Corynebacterium↗
PubMed1986

Comparative activity of ofloxacin and seven other antimicrobials against urea-splitting microorganisms.

Urinary tract infections caused by urea-splitting bacteria are severe clinical conditions and very difficult to treat due to their association with calculi, and because such bacteria form ammonium hydroxide raising the urinary pH and thereby creating an unfavourable condition for the action of most antimicrobials. We tested ofloxacin, norfloxacin, nalidixic acid, amoxicillin, amoxicillin-clavulanic acid, gentamicin, co-trimoxazole and nitrofurantoin against 143 gram-negative and 99 gram-positive bacteria, all urea-splitting, isolated from patients with urinary tract infections. All drugs were tested using media at two different pHs (pH 7.4 and PH 8.5) and two inoculum sizes (10(4) and 10(6) cfu). Although ofloxacin and norfloxacin had a similar spectrum of activity, ofloxacin had somewhat greater intrinsic activity against gram-positive organisms. MICs of ofloxacin for 90% of Proteus mirabilis, indole-positive Proteus spp., Klebsiella pneumoniae, Staphylococcus aureus, coagulase-negative staphylococci and the Corynebacterium group D2 were greater than or equal to 4 mg/l. The activity of the other drugs varied, but there were many strains resistant to these antimicrobials. The pH and inoculum size did not significantly affect the activity of ofloxacin so that this drug should be useful for the treatment of urinary tract infections caused by the commonest urea-splitting bacteria involved in such infections.

Anti-Bacterial Agents↗
PubMedDate not supplied

Urinary tract infection caused by Corynebacterium group D2: report of 82 cases and review.

Corynebacterium group D2 (CGD2) is a slow-growing, urea-splitting, multiantibiotic-resistant microorganism that is frequently isolated from urine samples and that, in certain circumstances, produces infection of the lower urinary tract (acute and chronic cystitis) and the upper urinary tract (pyelonephritis). This paper analyzes (by means of a retrospective and partially prospective clinical protocol) our experience with 82 patients with CGD2 bacteriuria. The infection was symptomatic in 62% of cases, and the clinical diagnoses included acute and chronic cystitis and pyelonephritis with or without bacteremia. Because CGD2 infection of the urinary tract may require specific antimicrobial treatment and because CGD2 is a fastidious microorganism, we recommend prolonged incubation of urine cultures (up to 48-72 hours), especially if the routine culture is negative, when patients are symptomatic, have alkaline urine, or have struvite crystals in the urine sediment.

Adult↗