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J C Piffaretti

Publications and source records attributed to J C Piffaretti.

At least 55 records · Page 3Linked to original sources
PubMed1984

[Haemophilus influenzae isolated in Switzerland: antibiotic sensitivity and biotyping].

208 H. influenzae (HI) strains originating from the whole of Switzerland have been analysed for capsular serotype, biotype, and susceptibility to the following antibiotics: ampicillin, chloramphenicol, tetracycline, co-trimoxazole, and ceftriaxone. Serotype b is the commonest of the encapsulated strains. Biotypes II and III (respiratory tract) and I (invasive diseases) are the biotypes most encountered. Ceftriaxone is the most active among the antibiotics tested: 0.03 microgram inhibits 100% of strains, whether penicillinase producers (PP) or not. To evaluate the rate of resistant HI in Switzerland, 1883 isolates, 206 of which originated from invasive diseases (meningitis, epiglottitis, septicemia) have been considered. The PP rate is about 4%, irrespective of the group considered. Among the isolates from the invasive diseases, 3 were resistant to chloramphenicol, and 1 to ampicillin and chloramphenicol. The value of 4% for the PP strains is not very high; however, because of its powerful antibacterial activity and its high penetration into the cerebrospinal fluid, it seems reasonable to consider the use of a third generation cephalosporin, such as ceftriaxone, for the early treatment of meningitis in infants. If such a drug is indicated as a first-choice antibiotic for this meningitis it should be confined to this use only, to avoid the emergence of resistant strains.

Blood↗
PubMed1984

Penicillinase producing Neisseria gonorrhoeae in Zurich, Switzerland.

Of 1031 consecutive isolates of Neisseria gonorrhoeae examined before 31 July 1982, 30 strains showed beta-lactamase activity. All the penicillinase producing N gonorrhoeae (PPNG) strains were imported, 23 of them from South East Asia. One PPNG strain was identified as coming from Antigua and one from Chile, the first PPNG strains to be reported from these two countries. In 28 strains, the minimum inhibitory concentration (MIC) of penicillin was greater than or equal to 4.0 mg/l, and 15 strains were insensitive to tetracycline (MIC greater than or equal to 2.0 mg/l). Four strains were less sensitive to spectinomycin (MIC = 30 mg/l), while the remaining 26 were highly sensitive to this antibiotic. The African plasmid was found in only one strain (that originating from Antigua), and all other PPNG strains contained the Asian plasmid. Twenty PPNG strains contained the resistance plasmid together with the transfer plasmid. Auxotype determination showed that 18 PPNG strains were prototrophic whereas 11 were proline requiring.

Anti-Bacterial Agents↗
PubMed1983

[Epidemiology of Neisseria gonorrhoeae isolated in Switzerland: sensitivity to antibiotics and auxotyping].

In a study to determine the epidemiological situation of N. gonorrhoeae (NG) in Switzerland, 149 strains isolated from different regions over the period September 1981 to February 1982 were analyzed for sensitivity to various antibiotics (minimum inhibitory concentration [MIC] for penicillin G, ampicillin, cefuroxime, tetracycline, thiamphenicol, and spectinomycin) and for their auxotype. From the results obtained it can be concluded that (1) the PPNG (penicillinase producing NG) strains are not a problem at present in Switzerland; (2) 15% of the non-penicillinase producing NG strains are "less sensitive" to penicillin G (MIC equal to or greater than 0.5 micrograms/ml); (3) sensitivity level of the NG strains to the various antibiotics assayed and the auxotypes do not show any significant peculiarity when compared to the data reported in other countries; (4) penicillin G should still be used as the first choice antibiotic at present in Switzerland, with spectinomycin, thiamphenicol and cefuroxime as second choice antibiotics; (5) when compared according to the geographical origin of their isolation, the NG strains show specific peculiarities, a fact which could lead to an antibiotic therapy policy more suited to specific regions.

Anti-Bacterial Agents↗
PubMed1983

The plasmid pattern as an epidemiologic tool for Salmonella typhimurium epidemics: comparison with the lysotype.

In the study of a limited epidemic of Salmonella typhimurium infections, the plasmid content (pattern) of bacteria was used as an epidemiologic tool outside the hospital environment. Comparisons were made with lysotyping, resistance pattern determination (14 antibiotics), and biotyping. Plasmid pattern determination was found to be as useful and accurate as lysotyping, whereas resistance pattern determination was of more limited interest. However, in this report biotyping was of no use.

Bacteriophage Typing↗
PubMed1983

In vitro activity of norfloxacin against Neisseria gonorrhoeae.

Norfloxacin, an analogue of nalidixic acid, is a novel antibacterial compound active against both gram-negative and gram-positive pathogens. 142 Neisseria gonorrhoeae isolates proved to be remarkably sensitive to it; the MIC50 and MIC90 values for norfloxacin were 0.03 microgram/ml and 0.06 microgram/ml, respectively, for the strains resistant to the penicillins; for the strains susceptible to the penicillins, the same value of 0.03 microgram/ml was found both for the MIC50 and MIC90. 100% of the strains were inhibited by 0.125 microgram/ml of the drug: this concentration is far below the serum levels (1.5 micrograms/ml) achievable following normal dosage. Clinical trials should be performed to establish whether the activity in vivo corresponds to that found in vitro.

Microbial Sensitivity Tests↗
PubMed1982

[Evolution of the intestinal flora in patients under preventive treatment with cephalosporins].

The evolution of the intestinal flora has been studied in 20 patients undergoing chemoprophylaxis with cephalosporins. The patients, admitted to the Cantonal Hospital of Geneva for heart surgery, all received intravenous treatment initiated on the day of admission. Subsequently, one group continued to receive a cephalosporin orally while prophylaxis was discontinued in a second group. Microbiological analysis of aerobic bacteria in faeces demonstrated in both groups (1) a significant increase in resistance to beta-lactamines (ampicillin); (2) a parallel though lesser increase in resistance to other antibiotics (which shows the probable role of plasmids carrying drug resistance markers); and (3) an increase in bacteria known for their resistance to beta-lactamines (klebsiella, enterobacter, pseudomonas). These results demonstrate that a single intravenous administration of beta-lactamines has a selective effect on the intestinal flora and notably on bacteria which are known to be the cause of infectious diseases acquired in hospitals.

Administration, Oral↗
PubMed1982

Beta-lactamase-specifying plasmids isolated from Neisseria gonorrhoeae have retained an intact right part of a Tn3-like transposon.

In three beta-lactamase-producing strains of Neisseria gonorrhoeae, ampicillin resistance is due to the presence of a 7.4-kilobase plasmid. Heteroduplex analysis has shown that the R plasmid contains a 1.6-kilobase segment homologous to the right part (the region coding for the beta-lactamase) of the Tn3-like transposon Tn2301 the 1.6-kilobase DNA segment is not transposable, but it can give rise to a functional transposon, when linked to the left part of TN2301. This provides strong evidence that the R plasmids of N. gonorrhoeae are deletion derivatives of a plasmid that contained an entire TN3-like transposon.

Ampicillin↗
PubMed1978

[Epidemiology of resistance factors to antibiotics].

Resistance factors are small independent extrachromosomal DNA molecules (plasmids) conferring resistance on one or more antibiotics to the bacteria which harbour them; in Enterobacteriaceae and other gramnegative bacteria they are transferable by conjugation. The work is reviewed which has been undertaken to underline the importance of the R factors in nature, and more precisely in the current environment of the intestinal bacteria (animal and human gut, sewage) under the selective pressure of antibiotics or otherwise.

Adult↗
PubMed1977

Interaction of tetanus toxin and toxoid with cultured neuroblastoma cells. Analysis by immunofluorescence.

The primary interaction of tetanus toxin and toxoid with mouse neuroblastoma cells (C 1300, clone NB2A) in tissue culture was studied using direct immunofluorescence. Experiments were done in standard routine cultures and also those influenced by chemical modulators. There is a difference in the characteristic binding response between the growth culture cells (grown in presence of fetal calf serum) and differentiating culture cells (grown in absence of serum). Exposure to the toxin gives no visible effect on the cell division or viability in growth cultures; whereas in differentiating cells the processes are shortened and the adherence to the glass is diminished without involving significant cell death. The toxoid did not bind at all under the same experimental conditions. Since there was no biological effect in growth cultures we have called this binding ineffective, and in the case of the differentiating cells, effective binding. Stimulation of pinocytosis increases the uptake of toxin in both cultures. Presence of some surface bound toxin still remaining on the differentiating cells indicates the possibility of another sort of mechanism for internalization. Pre-treatment of the cells with neuraminidase or beta-galactosidase to alter the membrane gangliosides eliminates binding in growth cultures but not in differentiating cultures. From these results we suggest that even though the toxin may well bind to gangliosides, at least in the differentiating cultures they are not solely responsible for the fixation. The morphologically observed effective binding is probably that not related to gangliosides.

Binding Sites↗