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Biomedical subjects

S Stefani

Publications and source records attributed to S Stefani.

At least 91 records · Page 5Linked to original sources
PubMed1989

Failure to correlate ampicillin and amoxicillin resistance by standard disk susceptibility tests and minimal inhibitory concentration in Haemophilus species.

22 Haemophilus strains, isolated from lower respiratory tract infections, were tested for their susceptibility to ampicillin and amoxicillin using both MIC and Kirby Bauer methods. Ampicillin and amoxicillin resistance tested with MIC method was not exactly correlated with Kirby Bauer standard (10 mcg ampicillin and 25 mcg amoxicillin disks) inhibition zones method (error rate: 52.6%). Yet using a 2 mcg ampicillin and 5 mcg amoxicillin handmade disk, error range decreased to 14.8%. Beta-lactamase production on whole cells were for 6 strains of the 22 tested. After breaking the cell wall, 19 on the 22 strains were beta-lactamase producers, confirming the results obtained with the MIC method.

Amoxicillin↗
PubMed1988

Relationship between in vitro and in vivo radiosensitivity of lymphocytes in chronic lymphocytic leukemia.

A significant positive correlation was obtained between the in vitro radiosensitivity of the blood lymphocytes of patients with chronic lymphocytic leukemia (CLL) and the in vivo response of the total leukocyte count subsequent to radiation therapy. Four types of equations were used to represent and measure the effect of in vitro X-irradiation on lymphocytes from CLL patients and measure the response of patients to a course of radiotherapy. For the in vivo analysis we used data from 10 patients who were routinely treated with a total of 16 courses of radiation therapy. The total leukocyte count showed a uniform exponential decline during a course of therapy. According to the literature, about 25% of all CLL patients and about 50% of CLL patients with advanced disease are resistant to chemotherapy. The equations and indices of the present study may be useful to diagnose CLL patients who are prone to be resistant to chemotherapy.

Cell Survival↗
PubMed1988

In vitro interaction between cefotetan and aminoglycosides on Staphylococcus aureus and coagulase negative staphylococci, both methicillin-susceptible and -resistant.

The authors have evaluated the behavior of the interaction between cefotetan, a new cephalosporin with long acting resistance to the action of beta-lactamases, and gentamicin, amikacin and netilmicin against methicillin-susceptible and -resistant staphylococci. In 65.8% of the cases, drug combinations showed synergic effects. Results were subdivided for susceptibility or resistance to the drugs used in combination. In general, when both drugs were tested against methicillin-susceptible strains the results showed synergism.

Amikacin↗
PubMed1987

Enterococci and aminoglycosides: evaluation of susceptibility and synergism of their combination with piperacillin.

Some clinical isolates of enterococci were tested for susceptibility to gentamicin, tobramycin, amikacin and netilmicin. Five percent of Streptococcus faecalis tested demonstrated high level resistance (minimum inhibitory concentration (MIC) greater than 2024 micrograms/ml) to gentamicin, tobramycin and netilmicin, while amikacin had MICs greater than 128 micrograms/ml for all strains tested. Since a combination of a beta-lactam and streptomycin does not produce synergism against all strains of enterococci for an increase in the number of highly resistant strains, the effect of piperacillin plus gentamicin, tobramycin, and netilmicin was examined. The combination piperacillin + netilmicin seemed to be very effective against all enterococci tested.

Aminoglycosides↗
PubMed1987

Action of clindamycin-phosphate in foreign body infections due to Staphylococcus epidermidis in mice.

The virulence of Staphylococcus epidermidis strain slime producer was examined in an experimental model of foreign body infection in mice. In the course of this experimental infection the mice were injected with two antibiotics (clindamycin and cefazolin) active in vitro toward the Staphylococcus strain used. The results obtained after a week of antibiotic therapy show that clindamycin alone has a therapeutic action against the infection caused by S. epidermidis. Cefazolin showed a very poor therapeutic effect. The results are discussed on the basis of inflammatory reaction elicited from the foreign body and the characteristics of clindamycin in connection with the host's defense mechanisms.

Animals↗
PubMed1987

First microbiological approach to dactimicin, a novel aminoglycoside antibiotic.

Dactimicin (ST 900) is the first aminoglycoside antibiotic of Dactylosporangium origin. This drug shows resistance to many enzymes that destroy aminoglycosides. In this first approach, the authors have pointed out the activity of dactimicin against Gram-negative rods, particularly Klebsiella, Enterobacter, Serratia and Gram-positive bacteria, especially methicillin susceptible and resistant staphylococci. Dactimicin showed remarkable antibacterial activity against all strains tested; however this activity was strongly influenced by the inoculum size. The bactericidal activity of dactimicin towards some Gram-positive and Gram-negative bacteria was also evaluated.

Aminoglycosides↗
PubMed1987

The sensitivity of gram-negative and gram-positive bacteria to ofloxacin.

The in vitro antimicrobial activity of ofloxacin, a new fluorinated quinolone, was evaluated against 165 gram-negative rods, both fermentative and non-fermentative and against 57 gram-positive strains (coagulase-positive and -negative, staphylococci both methicillin-resistant and susceptible and Streptococcus faecalis). Minimal inhibitory concentrations were determined by using the macrodilution test and activity was compared with nalidixic acid, norfloxacin, ampicillin, piperacillin, ceftazidime and gentamicin for gram-negative rods, norfloxacin and gentamicin for Staphylococcus strains, and norfloxacin, ampicillin, piperacillin and gentamicin for enterococci. Ofloxacin inhibited all fermentative gram-negative bacteria tested, in a range of 0.05-3.12 micrograms/ml. It also had good antimicrobial activity against non-fermentative gram-negative strains: in fact it inhibited 90% of Acinetobacter and 80% of Pseudomonas aeruginosa tested at 3.12 micrograms/ml. Ofloxacin had good antimicrobial activity against Staphylococcus and Enterococcus tested.

Ampicillin↗
PubMed1987

The sensitivity of gram-negative and gram-positive bacteria to ofloxacin.

The in vitro antimicrobial activity of ofloxacin, a new fluorinated quinolone, was evaluated against 165 Gram-negative rods, both fermentative and non-fermentative, and against 57 Gram-positive strains (coagulase-positive and -negative staphylococci both methicillin-resistant and -susceptible, and Streptococcus faecalis). Minimal inhibitory concentrations were determined by using the macrodilution test and the activity was compared with nalidixic acid, norfloxacin, ampicillin, piperacillin, ceftazidime and gentamicin for Gram-negative rods; norfloxacin and gentamicin for Staphylococcus strains; and norfloxacin, ampicillin, piperacillin and gentamicin for enterococci. Ofloxacin inhibited all fermentative Gram-negative bacteria tested, in a range of 0.05-3.12 mcg/ml, and had good antimicrobial activity against non-fermentative Gram-negative strains: it inhibited 90% of Acinetobacter and 80% of P. aeruginosa tested, at 3.12 mcg/ml. Ofloxacin had a high antimicrobial activity against Staphylococcus and Enterococcus strains tested.

Anti-Bacterial Agents↗
PubMed1987

In vitro study of dactimicin (ST 900) against methicillin-susceptible and -resistant staphylococci.

The current knowledge on the antimicrobial activity of dactimicin is poor and limited to the study of its activity against gram-negative bacilli. The new acquisition about the use of aminoglycoside antibiotics in infections due to Staphylococci, induced us to evaluate the behavior of this drug against methicillin-susceptible and -resistant Staphylococci, in comparison with fortimicin A and amikacin. Dactimicin (ST 900) shows good antibacterial activity and a strong bactericidal effect at MIC concentrations in all strains tested.

Amikacin↗
PubMed1986

Distant metastases of nasopharyngeal carcinoma: a study of 256 male patients.

The records of 256 patients with nasopharyngeal carcinoma have been reviewed to determine the incidence and location of distant metastases. Sixty-three patients underwent autopsy. The incidence of distant metastases was 36% overall, and 51% in the autopsy patients. Bones, distant lymphnodes, liver, and lungs were the most common sites of distant metastases. Liver was the most common site in the autopsy patients. Compared to other major histological subtypes, undifferentiated carcinoma had the highest incidence of bone but lowest incidence of lung metastases. There was a strong correlation between advanced locoregional disease and distant metastases. Of those patients who developed distant metastases, 98% were discovered within 3 years or earlier. Thorough evaluation of the above organs/systems is indicated at the time of initial staging work-up and at follow-up, specifically for patients with advanced locoregional disease. A literature review of distant metastases in nasopharyngeal carcinoma is presented.

Autopsy↗
PubMed1986

New trends in the chemotherapy of staphylococcal infections.

The authors evaluated the susceptibility of some antibiotics against several Staphylococci subdivided in lyogroups and different resistance patterns: methicillin-susceptible/penicillin-susceptible (MS/PS), methicillin-susceptible/penicillin-resistant (MS/PR), methicillin-resistant/penicillin-resistant (MR/PR) and methicillin-resistant/penicillin-susceptible (MR/PS). The antimicrobial agents used were: methicillin, penicillin, rifampin, tetracycline, lincomycin, erythromycin, gentamicin and netilmicin. Netilmicin showed better activity against all Staphylococcus strains tested, particularly against coagulase-negative.

Anti-Bacterial Agents↗
PubMed1986

Studies on lincosamide antibiotic resistance in methicillin-susceptible and -resistant staphylococci.

Lincomycin and clindamycin are still effective against anaerobic bacteria, and their antibacterial activity has also been indicated against gram-positive aerobic cocci, chiefly Staphylococcus aureus. The present emergency due to epidemiological circulation of Staphylococci, especially coagulase-negative, methicillin-resistant, and the question of the current validity of the lincosamides, induced us to study the activity of lincomycin and clindamycin against staphylococci belonging to different lyogroups in comparison to erythromycin. Clindamycin showed good antibacterial activity while methicillan-resistant strains showed an increase in resistance to erythromycin and lincomycin.

Anti-Bacterial Agents↗
PubMed1986

Epidemiology of resistance to netilmicin and other aminoglycosides.

The authors carried out a study to evaluate the epidemiology and resistance of netilmicin, gentamicin, tobramycin and amikacin during the 1984-1985 period. Clinical specimens of different origin, drawn both from hospitalized and outpatients were used in the study. The strains were tested for their sensitivity to aminoglycosides. In particular the degree of resistance in both fermentative and non-fermentative gram-negative strains was determined. As previously pointed out in other works, netilmicin showed good antimicrobial activity in respect to other aminoglycosides.

Amikacin↗