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Biomedical subjects

F Biavasco

Publications and source records attributed to F Biavasco.

32 records · Page 2Linked to original sources
PubMed1991

In vitro activities of ramoplanin and four glycopeptide antibiotics against clinical isolates of Clostridium difficile.

Seventy strains of Clostridium difficile, all isolated from symptomatic patients, were found to be uniformly susceptible to ramoplanin, a new glycolipodepsipeptide antibiotic, and to four glycopeptides (vancomycin, teicoplanin, and two semisynthetic teicoplanin derivatives). Ramoplanin is recommended for further evaluation in the treatment of C. difficile-associated disease.

Anti-Bacterial Agents↗
PubMed1991

Selection of resistance to glycopeptide antibiotics in staphylococci.

Clinical strains belonging to ten Staphylococcus species were investigated for their abilities to develop single-step resistance in vitro to vancomycin and teicoplanin. Surviving clones were only recovered from strains of three species, namely S. aureus, S. epidermidis, and S. haemolyticus. A similar ratio of grown to plated cells (approximately 1 x 10(-8)) was mostly obtained from strains of S. aureus and S. epidermidis. Higher ratios (1 x 10(-6) to 1 x 10(-7)) were obtained from strains of S. haemolyticus, especially when exposed to teicoplanin. When tested for susceptibility, many survivors exhibited vancomycin and teicoplanin minimum inhibitory concentrations (MICs) below the drug concentration used for in vitro selection, probably due to an inoculum effect in the plating procedure. However, MICs were particularly high in many clones of S. haemolyticus (up to 12.8 microg/ml for vancomycin, and > or = 102.4 microg/ml for teicoplanin).

Anti-Bacterial Agents↗
PubMed1990

Use of DNA fingerprinting in an epidemiologic study of outbreak-specific and non-specific strains of group C Neisseria meningitidis.

DNA fingerprints of nine group C isolates of Neisseria meningitidis were obtained by digestion with three restriction endonucleases, BamHI, EcoRI, and HindIII. Identical restriction profiles were displayed by five strains isolated from two patients and three contacts during a localized outbreak of meningococcal disease in the area served by our laboratory. A slight difference, appreciable only in the fingerprints obtained with EcoRI, was observed between these isolates and a sixth one isolated from a clinical case occurring in the same area one year later. In contrast, three additional strains, recently isolated from patients in separate areas in Italy, gave restriction profiles differing strikingly from one another and from those produced by the strains isolated in our area.

DNA, Bacterial↗
PubMed1990

Nosocomial outbreak of systemic candidosis associated with parenteral nutrition.

Eight patients in two surgical units developed systemic candidosis during a 40-day period from June 5 to July 13, 1987 (in five cases Candida albicans was identified). Three of them died. All cases belonged to a group of 27 patients receiving parenteral nutrition (PN), while among the 108 patients who did not receive PN, no cases were observed (p = .000001). Candida was cultured from two PN bags administered to the cases. A specialized nutrition nurse was responsible for the PN compounding and for maintaining administration sets in the two wards involved. An epidemiological investigation, in which 19 uninfected patients who had had PN were used as controls, showed no significant difference between cases and controls except that lipids were more frequently added to bags administered to cases (p = .0005). Furthermore, the bags administered to cases contained a higher average number of multidose constituents (p = .0008) when the comparison was focused on the two days before the onset of symptoms. Given the favorable medium provided by lipids, even a low level contamination of PN solutions during compounding and/or administration could have been responsible for the exposure of cases to multidose vials suggests, although not conclusively, that an extrinsic contamination occurred during compounding. Six isolates of C albicans were available from four cases. C albicans was cultured from the pharyngeal swabs of two physicians and three nurses, including the specialized nutrition nurse.

Aged↗
PubMed1990

Further characterization of borderline methicillin-resistant Staphylococcus aureus and analysis of penicillin-binding proteins.

Eighty-nine Staphylococcus aureus strains were grouped according to their susceptibility or resistance to methicillin and oxacillin. The role of beta-lactamase in borderline methicillin resistance was confirmed by tests with beta-lactamase inhibitors, particularly when salt-supplemented medium was used. A penicillin-binding protein assay indicated that borderline methicillin-resistant S. aureus strains do not produce PBP 2a.

Bacterial Proteins↗
PubMed1989

[Staphylococcus haemolyticus. Bacterial resistance to teicoplanin and associated morpho-structural aspects].

To improve our understanding of the bases of teicoplanin resistance we studied a "one-step" mutant of S. haemolyticus from a morphological point of view. The results show that the organization of peptidoglycan is altered in the resistant S. haemolyticus strain. It is suggested that the alterations, including the spongier cell wall structure, may prevent the teicoplanin from reaching its target.

Anti-Bacterial Agents↗
PubMed1988

Distribution and antibiotic susceptibility of extraintestinal clinical isolates of Klebsiella, Enterobacter and Serratia species.

A total of 451 extraintestinal, clinically relevant strains of the Klebsiella, Enterobacter and Serratia spp. isolated over a nine-month period from hospitalized patients at four different centers in Italy were investigated. Identification using the API 20E system showed that isolates belonged to 12 different species. Overall, strains of Klebsiella, Enterobacter and Serratia were in a ratio of approximately 3.4:2:1. Fifty-nine per cent of all strains were from urinary specimens, 12% from respiratory secretions, 10% from wounds and abscesses, and lower percentages from other sources. All strains were tested for their susceptibility to ten antibiotics. The rate of resistance to most drugs was generally greater in Enterobacter and Serratia than in Klebsiella. The overall incidence of strains of the intermediate category (i.e. between full sensitivity and resistance) was unexpectedly high. Both the relative frequency and the antibiotic susceptibility of strains of the various species varied from center to center; possible reasons for such differences are examined.

Drug Resistance, Microbial↗
PubMed1982

Production of inhibitors of lytic activity in the Micrococcaceae.

Eight Staphylococcus xylosus strains lacking lytic activity (LA) were found to excrete agar-diffusible factors inhibiting the LA of LA-positive strains of the same species. The same eight strains, when tested against LA-positive indicator strains from other species of Micrococcaceae, caused marked LA inhibition only of strains of S, saprophyticus and S. cohnii, both species closely related to S. xylosus. Micrococci and planococci, unlike staphylococci, do not normally show LA, yet Micrococcus lylae and M. sedentarius strains produced inhibitors effective against the LA of almost all the indicator strains, and planococci inhibited the LA of a few indicator strains. Micrococcus luteus strains caused LA inhibition of homologous indicators only, i.e. exceptional M. luteus strains exhibiting LA. Thus, a specific and a non-specific type of LA inhibition can be distinguished, and it is suggested that the apparent lack of LA might, in some instances, be explained by the simultaneous production of a specific inhibitor.

Bacteriolysis↗
PubMed1981

Clinical distribution and antibiotic sensitivities of staphylococcal strains isolated over an eight-month period.

A total of 842 staphylococci isolated from clinical material over an eight-month period and regarded as probable pathogens were identified according to lyogroup. Almost half the isolates belonged to lyogroups other than lyogroup I (Staphylococcus aureus), suggesting that coagulase-negative staphylococci are increasingly involved in human infections. All isolates were tested for sensitivity to 12 antibiotics. A greater resistance was observed in non-lyogroup I isolates, which again suggests a pathogenic significance of coagulase-negative staphylococci. Only lyogroup I strains, however, were obtained more frequently from clinical isolates than from healthy human skin. The distribution of the isolates in each lyogroup according to their clinical source is reported.

Anti-Bacterial Agents↗