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Biomedical subjects

J F Acar

Publications and source records attributed to J F Acar.

At least 19 recordsLinked to original sources
PubMed1978

International comparison of prevalence of resistance to antibiotics.

Prevalence of bacterial resistance to antibiotics was found to be substantially different in two separate regions of the world. The average percent resistant to individual antibiotics was nearly three times greater, and the percent of isolates resistant to six or more antibiotics 14 times greater among isolates at the Hôpital St Joseph in Paris than among those at the Peter Bent Brigham Hospital in Boston or at any of six US hospitals. Differences were not due to culture sampling or susceptibility testing methods used in the hospitals. Differences were nearly as great between isolates from patients recently admitted to the two hospitals, suggesting differences in the bacterial flora of their communities. Similar systematic comparisons of resistance prevalence in different parts of the world might help to define optimal antibiotic usage practices.

Anti-Bacterial Agents↗
PubMed1978

Chloramphenicol resistance in Streptococcus pneumoniae: enzymatic acetylation and possible plasmid linkage.

Clinical isolates of Streptococcus pneumoniae resistant to chloramphenicol were observed in France for the first time in 1973. During a 4-year survey, these strains were found to represent 6% of a total of 564 isolates of S. pneumoniae in a general hospital and to belong to 13 different serotypes. One such strain, referred to as BM 6001, was shown to inactivate chloramphenicol, and the process was found to be inducible. The inactivated products were demonstrated to be O-acetoxy esters of chloramphenicol. The synthesis of an inducible chloramphenicol acetyltransferase was shown to be responsible for the inactivation of the drug. The resistant strain was able to transfer the chloramphenicol marker by transformation to competent strains of pneumococci at a frequency of 1% of that observed for control chromosomal markers. The loss of resistance was enhanced by ethidium bromide treatment, but no chloramphenicol-resistant mutant was isolated by mutagenesis of a "cured" clone or naturally susceptible isolates. All attempts to isolate plasmid deoxyribonucleic acid as covalently closed circular molecules from strain BM 6001 have been unsuccessful, but epidemiological evidence and the fact that the genes specifying chloramphenicol acetyltransferase synthesis are usually located on plasmids suggest that this marker may be plasmid-borne in S. pneumoniae.

Acetylation↗
PubMed1978

Human infections caused by thiamine- or menadione-requiring Staphylococcus aureus.

Stable dwarf forms of Staphylococcus aureus have been identified in clinical specimens as the sole or predominant isolate in eight cases. These organisms have been shown to be menadione or thiamine dependent, i.e., cultivation in the presence of one of these agents has permitted growth of colonies which appear typical of S. aureus. In vitro resistance to aminoglycosides was overcome by cultivation in the presence of menadione or thiamine. Menadione- or thiamine-requiring S. aureus can be considered as causative agents in severe human infections. Special care must be taken if they are to be identified in pathological specimens. Their antibiotic sensitivity testing should be done comparatively on supplemented and nonsupplemented media.

Aminoglycosides↗
PubMed1978

Bacterial persistence in vivo: resistance or tolerance to antibiotics.

The in vivo persistence of bacteria in spite of "adequate" therapy may be due to a variety of causes or factors. The most "obvious" cause is the presence of drug resistant strains, missed in conventional testing because of heterogeneity of resistance, special test requirements or emergence during treatment. A second large group of causes is due to atypical forms, whereas a third cause is due to tolerance. A fourth group of causes may be termed invironmental factors, and this includes drug inactivation, bioconversion or antagonism, often a result of the infection itself.

Animals↗
PubMed1978

[Sensitivity of bacteria to antibiotics. Evaluation of a rapid automatic method (author's transl)].

A rapid automated sensitivity testing system is evaluated in this report. The results have been compared with the standard disk diffusion method (ICS). Three hundred strains recently isolated from clinical cases : Enterobacteriaceae, Staphylococcus aureus, Streptococci D, Pseudomonas aeruginosa, have been tested. The general agreement between the two techniques was 89 p. cent.

Anti-Bacterial Agents↗
PubMed1977

[Septicemia in the elderly (author's transl)].

Out of 1,251 patients above 65 years of age staying at the Charles Foix Hospital (prolonged hospitalization) and the St. Joseph Hospital (acute cases), 168 had one or more positive blood cultures. Urinary tract infection is a major source of septicemia due to gram negative bacilli. It is important to stress cases of septicemia due to pneumococcal pneumoniae, eschars, and other skin lesions. Mortality varies between 33 and 36%, depending upon the hospital. Collapse, although infrequent, still portends a grave prognosis (61% of cases of collapse led to death at Charles Foix Hospital). The combination of more than two risk factors considerably worsens the prognosis. Hypoproteinemia and dementia are every bit as grave as diabetes and cancer. A better isolation of the microorganisms involved in cases of septicemia in the elderly will lead to a more judicious choice of antibiotics. The administration of chemotherapy immediately after the samples were obtained remains the main guarantee of successful therapy.

Aged↗
PubMed1977

[Drug sensitivity of Haemophilus sp. and transfer of resistance into E. coli (author's transl)].

From June 1973 to July 1976, 742 strains of Haemophilus influenzae and parainfluenzae, isolated from clinical specimens, were routinely tested for in vitro sensitivity to twelve antibiotics: penicillin, ampicillin, cephalothin, streptomycin, kanamycin, gentamicin, chloramphenicol, tetracyclin, minocyclin, erythromycin, sulfamethoxazol, trimethoprim. 61 strains were found resistant to one or more of these antibiotics (ampicillin, kanamycin, chloramphenicol and tetracyclin). The MICs of 23 antibiotics were determined by the agar dilution method on most of the resistant strains and on 60 sensitive strains isolated during the same period and considered as control. 21 strains transferred their resistance determinants into E. coli K12; 23 plasmids were obtained isolated from these strains: 2 strains contained two different plasmids. 90% of the transconjugants were stable after repeated subcultures.

Anti-Bacterial Agents↗
PubMed1977

[Trimethoprim resistance plasmids: transferability and incompatibility groups (author's transl)].

Over a three year period, 119 strains of enterobacteria isolated from patients have been found resistant to trimethoprim (TMP) and sulfonamides (Su); 11 strains were resistant to TMP only. MIC of TMP were between 32 and 2048 microng/ml. Three groups of strains are described: (1) thymineless variants (2 strains); (2) TMP resistance non-transferable into Escherichia coli K12 (95 strains); (3) TMP resistance transferable into E. coli K12 (33 strains). TMP marker and Su marker have been transferred independantly from 13 strains; they were cotransferred from 20 strains. The incompatibility group of 31 plasmids has been determined: 10 belong to the fi+ type, group FII; 21 belong to the fi--type, group 6, group 7, group 10, group N and group I1. Epidemiological implications of such a wide range of incompatibility groups among a small number of plasmids specifying TMP resistance are discussed.

Drug Resistance, Microbial↗
PubMed1976

[Gonococcal septicemia. 1 case].

This paper describes a case of disseminated gonococcal infection, a rare disease in France. A 41 year-old woman was hospitalised with acute polyarthritis and characteristics skin lesions. Jaundice and liver function abnormalities are difficult to interpret due to a preexisting alcoholic cirrhosis. The possibility of an endocarditis is raised because of a systolic murmur heard at the base of the heart. Bacteriological identification of N. Gonorrhoeae is carried out in blood culture; it has also been recovered by scrapings of a cutaneous bullae by staining only. Therapy was instituted by daily intravenous penicillin G sodium 50 000 000 u. and intramuscular gentamicin 160 mg for 45 days. There resulted good clinical and bacteriological response. The elements of clinical and bacteriological diagnosis, as well as the therapy are discussed.

Acute Disease↗
PubMed1976

Suceptibility of aminoglycoside-resistant gram-negative bacilli to amikacin: delineation of individual resistance patterns.

Gram-negative bacilli isolated from clinical specimens submitted for culture in two Paris hospitals during 1974 were studied for susceptibility to six currently used aminoglycosides: kanamycin, neomycin, paromomycin, lividomycin, gentamicin, and tobramycin. Resistance patterns of strains of various species including those of Enterobacteriaceae, Pseudomonas, and Moraxella were determined, and the strains were grouped into eight resistance "phenotypes." In comparative studies of 807 strains belonging to different phenotypes, amikacin was markedly more active than any of the six other antibiotics; at concentrations of less than or equal to 4 mug/ml, it inhibited about 88% of the strains, including those resistant to gentamicin and tobramycin. Some amikacin-resistant strains were found among different species. The mechanism of resistance to amikacin of strains of Serratia and Moraxella group II was related to an N-acetylating enzyme. Amikacin can be expected to be useful as an alternative treatment of infections due to gram-negative bacilli sensitive to aminoglycosides and also, more particularly, for the treatment of patients infected with multiresistant strains.

Amikacin↗