Search

A strain of Listeria monocytogenes, isolated from a patient with meningoencephalitis, was resistant to chloramphenicol, erythromycin, streptomycin, and tetracycline. The genes conferring resistance to these antibiotics were carried by a 37-kb plasmid, pIP811, that was self-transferable to other L monocytogenes cells, to enterococci-streptococci, and to Staphylococcus aureus. The efficacy of transfer and the stability of pIP811 were higher in enterococci-streptococci than in the other gram-positive bacteria. As indicated by nucleic acid hybridisation, the genes in pIP811 conferring resistance to chloramphenicol, erythromycin, and streptomycin were closely related to plasmid-borne determinants that are common in enterococci-streptococci. Plasmid pIP811 shared extensive sequence homology with pAM beta 1, the prototype broad host range resistance plasmid in these two groups of gram-positive cocci. These results suggest that emergence of multiple antibiotic resistance in Listeria spp is due to acquisition of a replicon originating in enterococci-streptococci. The dissemination of resistance to other strains of L monocytogenes is likely.

Because of the poor specificity of the arteriography, the authors have performed a percutaneous angioscopy before every angioplasty of the arteries of lower limbs for nearly 3 years. They define the angioscopy and describe materials and technique. The percutaneous route without surgery and without anesthesia underlines the originality of the technique. The great difficulty is to counter-pulse the arterial inflow. The rate of saline irrigation and all the means of arterial blockade are described. In the second part, the "elementary images" are classified. The authors insist on the specificity of the angioscopy in the interpretation of arterial obstructions. Because of this specificity, the right treatment can be applied to any type of lesion. Angioscopy permits to foresee endoluminal surgery technique.

A study on the long-term efficacy of femoral-popliteal angioplasty was carried out on 185 angioplasty cases over a 5 year follow-up period. A classification of data according to the type of lesion treated, revealed that results were favorable in case of stenosis (87%), short obstruction (70%) and long obstruction (35%). A special study of the outcome of treatments for stage IV arteritis was carried out. After comparing results with those obtained by other teams, the authors list the complications encountered, hematomas, and thromboses, and show their current tendency for regression. Lastly, the authors stress the advantages of angioscopy, which permits to identify the nature of the treated lesions and to predict possible complications, which are usually underrated by angiography.

A well-mastered technique will cause percutaneous transluminal angioplasty of iliac arteries to achieve long-term results comparable to those obtained surgically. In isolated iliac stenosis, a 95% good result rate is attained (81% cured, 14% improved). More complex cases of iliac stenosis yield 90% good results (72% cure), with a mean Doppler ankle/arm pressure index gain of 0.5 point in a series including 673 patients at 5 years follow-up. Only the presence of combined distal femoral lesions may cause the good result score to drop to 85%, including merely 35% cure. General complications are practically lacking and local complications are minimal, which incites one to propose this technique as a first-line treatment of iliac stenosis whenever distal blood circulation is maintained.

Angioscopy is a technique of endoscopic investigation of the vascular lumen and its contents, which we have coupled with iliac and femoral angioplasty. The material comprises 3 main elements: the angioscope, the TV-monitoring assembly and the infusion system. No complication was recorded in a series of 94 angioscopies (47 iliac, 44 distal femoral and 3 grafts) performed over a period of 18 months. The technical quality of the images obtained was good in 90% of cases (85/94). Angioscopy revealed lesions that had either been nonvisualized or underrated by angiography, and played a determinant role in 16% of cases (15/94), whereby the therapeutical procedure could be modified accordingly.

Excision is probably the initial and rate-limiting step of the movements of conjugative transposons of Gram-positive bacteria such as Tn916 and Tn1545. We have shown, by molecular cloning and DNA sequencing, that a 2058 bp Sau3A right-junction fragment of transposon Tn1545 specifies two gene products that are involved in the excision of the element. The DNA sequence of these genes, designated orf1 and orf2, has been determined and the corresponding proteins, ORF1 and ORF2, have been identified in a bacterial cell-free coupled transcription-translation system. These proteins are freely diffusible since they are able to trans-complement in vivo a deletion derivative of Tn1545 defective for excision. Using an in vivo complementation assay, we have demonstrated that ORF2 alone is able to catalyse excision and that ORF1 strongly stimulates the activity of ORF2. We also found that ORF1 and ORF2 display local homology with, respectively, proteins Xis and Int from lamboid phages, which suggests that these excision systems have a common origin. Based on the functional properties of the integrase of bacteriophage lambda, on the analysis of the nucleotide sequence of the junction fragments and of the target before insertion and after excision, a model is proposed for ORF2-catalysed excision of Tn1545 and related conjugative transposons.

Salmonella ordonez (BM 2000) codes for kanamycin (Km, aphA), ampicillin (Ap), streptomycin (SmSp:aadA and Sm:aphC), chloramphenicol (Cm), tetracycline (Tc) and sulfonamide (Su) resistances and for production of colicin Ib (Cib). Genetical analysis by incompatibility testing, conjugation, transformation and physical studies using electron microscopy, agarose gel electrophoresis, led us to associate the Km and Cib characters to a 98.7 kilobase (kb) IncI1 plasmid (pIP565), and the Sm (aphC) and Su determinants to a 8.3 kb plasmid (pIP605). The ApCmSmSp(aadA)SuTc determinants were not associated in BM2000 S. ordonez with a plasmid structure. Following conjugation of S. ordonez to E. coli, the ApCmSmSpSuTc determinants were found stably associated with a single plasmid structure (pIP173, 127.5 kb) belonging to IncI1 group. Agarose gel electrophoresis of plasmid DNA restriction endonuclease digests and electron microscopy heteroduplex analysis showed that the acquisition of the ApCmSmSpSuTc determinants resulted from the insertion into pIP565 of a 28.8 kb DNA sequence. This sequence coding for ApCmSmSpSuTu resistances in S. ordonez could be translocated either to pIP565 plasmid or to several IncI1 plasmids but never to plasmids belonging to IncW, IncP or IncFII, suggesting the existence of specific sequences on the IncI1 receptor plasmids. Moreover, R-determinants were translocated back "en bloc" from pIP173 to the chromosome of a susceptible S. ordanez. The results were consistent with the presence in BM2000 S. ordonez chromosomal DNA of an integrated translocatable sequence encoding ApCmSmSpSuTc resistances. Such a structural association could account for the stability of these resistances in the Salmonella ordonez serotype.

The possibility of transfer of genetic information by conjugation from gram-positive to gram-negative bacteria was investigated with a pBR322-pAM beta 1 chimeric plasmid, designated pAT191. This shuttle vector, which possesses the tra functions of the streptococcal plasmid pAM beta 1, was conjugatively transferred from Enterococcus faecalis to Escherichia coli with an average frequency of 5 x 10(-9) per donor colony formed after mating.

The vitamin A status of 105 elderly French people was assessed by ocular impression cytology with transfer (ICT). 5 patients (4.8%) had a negative ICT defined by the absence of goblet cells and the enlargement of the epithelial cells (deficient vitamin A status). 100 patients had a positive ICT with goblet cells and small, numerous epithelial cells (sufficient vitamin A status). ICT results were compared to serum biochemical parameters. Mean serum levels of retinol, retinol-binding protein (RBP) and transthyretin (TTR) were significantly lower while C-reactive protein (CRP) and orosomucoid were significantly higher in negative ICT than in positive one. The etiology of vitamin A deficiency is difficult to conclude (malnutrition, vitamin A deficiency, inflammation). ICT is a good indicator of peripheral vitamin A deficiency in our experience.

We described a new method to stain epithelial cells harvested by ocular impression. The cells are immediately transferred on a glass slide after the sampling; this transfer permits a very simple staining and easier reading by light microscopy. The results are compared with those obtained with the previous techniques and confirm ocular impression as a good help for vitamin A status determination.

Staphylococcus haemolyticus BM4610 was resistant to high levels of lincomycin and susceptible to macrolides, clindamycin, and streptogramins. This resistance phenotype, not previously reported for a human clinical isolate, was due to inactivation of the antibiotic. The gene conferring resistance to lincomycin in strain BM4610 was carried by a 2.5-kilobase plasmid, pIP855, which was cloned in Escherichia coli. Plasmid pIP855 caused inactivation of both lincomycin and clindamycin in S. haemolyticus and in E. coli but conferred detectable resistance to lincomycin only in S. haemolyticus and to clindamycin only in E. coli.

We studied two outbreaks of calf salmonellosis caused by apramycin and gentamicin-resistant Salmonella typhimurium strains. In both cases, the responsible strains were resistant to ampicillin, chloramphenicol, kanamycin, streptomycin, tetracycline, and trimethoprim; one strain was also resistant to nalidixic acid in one outbreak. A systematic survey of the intestinal Escherichia coli strains of calves from the two affected flocks showed that 11 of 24 animals sampled were also colonized by apramycin- and gentamicin-resistant E. coli strains. These isolates belonged to four biotypes and were resistant to ampicillin, chloramphenicol, kanamycin, streptomycin, tetracycline, trimethoprim, and nalidixic acid. All of the strains were resistant to high levels of apramycin (MICs, 512 to 1,024 micrograms/ml) and to gentamicin (MICs, 8 to 32 micrograms/ml), and these resistances were always transferred en bloc. In S. typhimurium, this coresistance was borne by plasmids that were approximately 39 kilobases long (outbreak 1) or 90 kilobases long (outbreak 2), whereas in E. coli, the coresistance was due to plasmids that were approximately 110 kilobases long in both outbreaks. The two plasmids of Salmonella and four plasmids of E. coli encoded type IV aminoglycoside 3-N-acetyltransferases. The intensive use of curative and preventive treatments in calf production could be responsible for the emergence of enzymic resistance to apramycin and gentamicin.

The apparently chromosomally encoded 3',5"-aminoglycoside phosphotransferase (type III), from the high-level aminoglycoside-resistant Streptococcus pneumoniae BM4200, was compared with homologous enzymes coded for by the plasmids pJH1 and pSH2, originally isolated from Streptococcus faecalis and Staphylococcus aureus, respectively, and also found in a wild strain of S. aureus, BM4600. The enzymes appeared to be indistinguishable, and we conclude that the gene encoding 3',5"-aminoglycoside phosphotransferase (type III) can cross generic barriers within gram-positive cocci.

The aminoglycoside phosphotransferase (APH)(3')(5'')-III has been characterized from Streptococcus pneumoniae BM4200, which is resistant to high levels of aminoglycosides. The phosphotransferase was apparently chromosomally-encoded and was responsible for the high-level resistance. The enzyme was not notably pH-dependent, was heterogeneous after isoelectric focusing, with pI values of approximately 4.8 and 5.1, and had an apparent molecular weight of 32 500 after SDS-PAGE.

Streptococcus faecalis strain BM6217 was resistant to high levels of all the clinically useful aminoglycoside antibiotics. This broad aminoglycoside resistance was mediated by constitutively synthesized phosphotransferase, acetyltransferase, and adenylyltransferase activities. It was inferred that phosphorylation occurred at the 3', 5", and 2"-hydroxyl groups, acetylation at the 6'-amino group, and adenylylation, probably, at the 6-hydroxyl group of the aminoglycosides. Strain BM6217 remained susceptible to the aminocyclitol spectinomycin but the combination of penicillin G with that antibiotic appeared antagonistic to this strain.

The conjugative shuttle transposon Tn1545 from Streptococcus pneumoniae confers resistance to kanamycin (aphA-3), erythromycin (ermAM), and tetracycline (tetM). The 25.3-kb element is self-transferable to various gram-positive bacterial genera where it transposes. Tn1545 is also capable of transposition, but not of conjugation, after cloningoff Escherichia coli. Analysis of the element by restriction endonucleases, molecular cloning, electron microscopy of heteroduplexes, DNA hybridization, and sequencing allowed us to establish a physical map of Tn1545, localize the resistance genes, determine their direction of transcription, and compare them with other characterized resistance determinants, and show that Tn1545 is not flanked by large terminal repeated sequences in opposite orientation.

Despite the progress in functional investigation procedures, phlebography remains the standard test in venous disease of the lower extremities. The development of better quality contrast media has significantly improved patients tolerance. After a review of the regular, routine procedure, the authors stress the technic's pitfalls. Uncomplicated pitfalls are air bubbles, Venturi's effect, venous malformations, and superimposed venous axes or gases. This type of problems is easily circumvented. Flow images caused by confluent axes of high-flow veins (internal iliac veins, renal veins) or layer courants (gutter effect) are presented as a reminder. Compression images are often more treacherous: related to normal veins: compression of left iliac vein by aortic junction; of inferior vena cava by enlarged aorta or by osteophyte; tourniquet too low, iliac vein compressed by a dilated bladder; or compression due to intramuscular hematoma,... related to pathological veins: to be mentioned are bridle-caused obstruction of the popliteal vein (Klippel-Trénaunay syndrome), and retroperitoneal fibrosis. Although the present description of phlebography-related pitfalls is neither new, nor exhaustive, it should be reconsidered, as phlebography of the lower limbs, while being currently better tolerated, is still an update technic that needs to be rendered more reliable.

Bacillus circulans NRRL B-3312 produces the aminoglycoside antibiotic butirosin and encodes an aminoglycoside 3'-phosphotransferase. We detected a 48 kilobase plasmid, pIP850, in this strain; this was analyzed by agarose gel electrophoresis following digestion with EcoRI restriction endonuclease and by nucleic acid hybridization. The results obtained indicate that plasmid pIP850 does not carry the structural gene for the aminoglycoside modifying enzyme.

A mobile genetic element, designated Tn1545, was detected in the chromosome of Streptococcus pneumoniae BM4200, a clinical isolate multiply resistant to antibiotics. The 25.3 kb element conferred resistance to kanamycin and structurally related aminoglycosides by synthesis of a 3'-aminoglycoside phosphotransferase type III (aphA-3), to macrolide-lincosamide-streptogramin B-type antibiotics (ermAM), and to tetracycline (tetM). Tn1545 was self-transferable to a recombination deficient S. faecalis strain where it was able to transpose to various sites, induce insertional mutations and was apparently cleanly excised. The element also conjugated to and transposed to the chromosome of S. faecalis, S. lactis, S. diacetylactis, S. cremoris, S. sanguis, Staphylococcus aureus, and Listeria monocytogenes. The properties of the conjugative transposon Tn1545 could account for the sudden emergence, rapid dissemination, and stabilisation of multiple resistance to antibiotics in S. pneumoniae in the absence of plasmids.

The nucleotide sequence of the kanamycin resistance determinant aphA-3 encoded by transposon Tn1545 from Streptococcus pneumoniae was determined and compared to those of plasmids pJH1 and pIP1433 from Streptococcus faecalis and Campylobacter coli, respectively. The three sequences were found to be identical and differed by two substitutions and the deletion of a codon from that of plasmid pSH2 from Staphylococcus aureus. Comparison of the 5' noncoding sequences indicated that the regions containing the aphA-3 gene in pJH1 and in Tn1545 evolved independently by deletion from a sequence similar to that found in pIP1433. In the latter plasmid, aphA-3 is transcribed from a promoter, P1, which is flanked by two 12-base pair direct repeats. The rearrangement observed in pJH1 removed one of these recombinogenic sites and altered the -10 and 3' flanking sequences of P1. The promoter thus generated. P1', allows expression of similar level of kanamycin resistance as P1. However, fusion experiments carried out with a promotorless chloramphenicol acetyltransferase gene indicated that the canonical promoter P1 is significantly less efficient than P1'. From analysis of the thermodynamic properties of these promoters, we conclude that this difference in strength reflects the melting properties of the -10 sequences. The transition from pIP1433 to pJH1 may correspond to the progression of a molecule structurally unstable to a more stable one combined with the need to maintain an efficient promoter upstream of the aphA-3 gene. The deletion event in Tn1545, which occurred between the two 12-base pair directly repeated sequences, removed P1 in its entirety.(ABSTRACT TRUNCATED AT 250 WORDS)

Acinetobacter calcoaceticus strain BM2500 was resistant to ampicillin, aminoglycoside-aminocyclitols, chloramphenicol, sulfonamides, and high levels of trimethoprim. Resistance to ampicillin was due to the presence of a beta-lactamase (TEM-1) and the aminoglycoside-aminocyclitol resistance was mediated by phosphotransferase (APH(3')(5")I) and adenylyltransferase (AAD(3)(9] activities. The resistance genes were carried by a 167 kilobase plasmid, pIP1031, belonging to incompatibility group 6-C; the plasmid was self-transferable, at extremely low frequency, to Escherichia coli by conjugation. Plasmid pIP1031 DNA was analyzed by agarose gel electrophoresis following restriction endonuclease digestion, by nucleic acid hybridization, and by CsCl analytical density gradient ultracentrifugation. The results support the hypothesis that plasmid pIP1031 may have been acquired recently by strain BM2500.

Streptococcus faecalis BM4100 was resistant to high levels of gentamicin, kanamycin, and structurally related antibiotics. The genes conferring resistance to aminocyclitols in this strain were carried by a plasmid, pIP800, self-transferable to other S. faecalis strains. The aminocyclitol resistance was mediated by constitutively synthesized phosphotransferase and acetyltransferase activities. It was inferred that phosphorylation occurred at the 2"-hydroxyl group and that acetylation occurred at the 6'-hydroxyl group of the aminocyclitols. The enzyme activities were not separable by gel filtration or by isoelectric focusing. Their apparent molecular weight was 31,000, and their isoelectric point was 5.3. With respect to substrate profile, size, and charge, the transferases from strain BM4100 resembled closely those with identical site specificity described in staphylococci. These results suggest that plasmid gene transfer may occur between the two pathogenic bacterial genera.

The serum of 392 French healthy children aged 1-16 years was analysed for vitamin A, vitamin E, beta-carotene and cholesterol contents. The study group consisted in 185 females and 207 males, living in the area of Tours, France. The mean serum values are 42.05 +/- 12.0 micrograms/dl for vitamin A, 572 +/- 381 micrograms/l for beta-carotene and 9.5 +/- 2.5 mg/l for vitamin E. According to sex distribution, mean values of studied micronutrients levels are higher in boys than in girls, but not significantly. Vitamin A and vitamin E serum levels increased with age. Vitamin E peripheral level is strongly correlated with total cholesterol serum value. The results are compared to those of underdeveloped countries children groups studies. At least, decreased vitamins levels are observed among five per cent of children and are examined as being at risk to develop a deficiency.

Tn1545, from Streptococcus pneumoniae BM4200, confers resistance to kanamycin (aphA-3), erythromycin (ermAM) and tetracycline (tetM). The 25.3 kb element is self-transferable to various Gram-positive bacterial genera where it transposes. Tn1545 was cloned in its entirety in the recombination deficient Escherichia coli HB101 where it was unstable. The three resistance genes aphA-3, ermAM and tetM were expressed but were not transferable to other E. coli cells. Tn1545 transposed from the hybrid plasmid to multiple sites of the chromosome of its new host. The element re-transposed, at a frequency of 5 X 10(-9), from the chromosome to various sites of a conjugative plasmid where it could be lost by apparently clean excision. The element transformed and transposed to the chromosome of Bacillus subtilis. The properties of the conjugative shuttle transposon Tn1545 may account for the recent emergence of genes from Gram-positive bacteria in Gram-negative organisms.

Very few papers about peripheral angioscopy are reported in literature. Percutaneous angioscopy (P.T.A.) of 25 peripheral arteries (21 iliac and 4 femoral arteries) have been performed by the authors without surgery and without anesthesia. Three observations are selected. The first one demonstrates an eccentric stenosis altering its diameter during pulsations; an irregular ulcerated atheroma is observed. The second case shows the signs of a centric atheroma with an intimal fragment. The last one is an intimal dissection due to PTA. The prospective aspects of this new technique are discussed.