Nosocomial rotavirus infections in adult renal transplant recipients.

We conducted a 24-month survey of hospital-acquired rotavirus infections in 20 renal transplant recipients who received their graft during 1988. Four cases of nosocomial rotavirus infection were diagnosed (20% of patients), 3-34 days after graft. Two patients presented with severe diarrhoea and two with fever alone. The cases occurred mainly during the winter months and remained sporadic. None of our patients was found to have chronic excretion of rotaviruses. Contacts from paediatric cases can be ruled out. We concluded that rotavirus nosocomial infections were frequent in adult renal transplant recipients and suggest that screening for rotavirus is regularly performed in these immunodeficient patients who are very susceptible to hypovolaemia.

Resistance to beta-lactams in Enterobacteriaceae: distribution of phenotypes related to beta-lactamase production.

Phenotypes of susceptibility to amoxycillin (Amo), ticarcillin (Tic), cephalothin (Ctn) were determined in 1366 isolates of Enterobacteriaceae by disk method and beta-lactamases were identified in 243 strains belonging to different phenotypes of amoxycillin-resistant strains. AmoR TicR CtnS strains (25%) were penicillinase producers and all of them were susceptible to the combination amoxycillin/clavulanic acid (Amo/CA) and ticarcillin/clavulanic acid (Tic/CA). Amo1/R TicS CtnR strains (12%) were cephalosporinase producers and resistance to Amo/CA was observed, except for Proteus vulgaris. AmoR TicR CtnR strains (18%) often produced two beta-lactamases (penicillinase and cephalosporinase) and they were resistant to Amo/CA; in this group, susceptibility to Tic/CA depends on the nature and the amount of the beta-lactamase produced, except for Serratia marcescens for which antibiotic resistance is probably due to other mechanisms. Tic/CA resistance was mainly found in Serratia marcescens (41%) and Enterobacter cloacae (36%).

[In vitro comparative study of piperacillin-aminoglycosides combinations against Enterococci and Enterobacteriaceae]. / Etude comparative in vitro d'associations pipéracilline-aminosides face aux entérocoques et aux entérobactéries.

The hundred and ninety-two combinations were tested against 17 strains chosen from the results of MIC determination (disc method): 5 enterococci exhibiting low level resistance (r) or high level resistance (R) to streptomycin (S) and gentamicin (G): 2 strains Sr Gr, 2 strains SR Gr and 1 strain Sr GR; 12 enterobacteria chosen for their resistance phenotypes to beta-lactams and aminoglycosides and because they are the most frequent clinical isolates: 2 strains Amos Tics Ctns (group 1), 4 strains AmoR Tics CtnR (gr. II), 4 strains AmoR TicR Ctns (gr. III) and 2 strains AmoR TicR CtnR (gr. IV). MIC and MBC were assessed for the 17 strains (Mueller Hinton broth). Combinations were carried out by a checkerboard micromethod. FBC index was calculated for each combination. Against enterococci the 50 combinations were: piperacillin versus ampicillin + aminoglycosides (streptomycin, tobramycin, amikacin, gentamicin, netilmicin). Against enterobacteria piperacillin was combined with different aminoglycosides depending on their resistance phenotypes. These combinations were compared with ticarcillin or mezlocillin or cefotaxime + aminoglycosides (total number 142). The species studied produced different results: with the enterococci Gr synergistic effects (FBC = 0.62-0.75) were rare; additive and indifferent effects were predominant. With the GR strain some antagonistic effects were observed. With the enterobacteria, in groups I and II synergistic effects were frequent and almost equivalent regardless of the beta-lactam chosen. In groups III and IV (TicR) piperacillin MICs were greater than or equal to 128 mg/l and mezlocillin MICs greater than 512 mg/l; the synergistic effects were significant (FBC from 0.25 to 0.62). beta-lactam + amikacin or netilmicin, and especially piperacillin + amikacin, were found to have the most frequent synergistic effects upon the strains tested. Mezlocillin combinations cannot be used clinically; the use of piperacillin combinations requires further discussion. On the other hand, cefotaxime + aminoglycosides combinations are active against those TicR strains.

[In vitro effect of piperacillin on aerobic bacteria. Variations according to the phenotypes of resistance to beta-lactam antibiotics]. / Activité in vitro de la pipéracilline sur les bactéries aérobies. Variations selon les phénotypes de résistance aux bêta-lactamines.

In a first study the MICs of piperacillin (PIP), mezlocillin (MEZ), azlocillin (AZL), carbenicillin (CARB) and ticarcillin (TIC) against 563 strains of aerobic bacteria were compared. The MIC50 of PIP against E. coli and P. mirabilis was 0.5 to 1 mg/l, that is equal to those of MEZ and TIC but 2 or 3 times lower than those of AZL and CAR. The MIC50 of PIP and MEZ against Klebsiella, a species that is naturally resistant to TIC and CAR, was 4 mg/l. Enterobacter, Serratia and Citrobacter showed two populations of strains: the first was sensitive to the five penicillins tested (MIC50 of PIP: 1 to 2 mg/l); the second was resistant to all of them. PIP and AZL were more active (MIC50 8 mg/l) against Ps. aeruginosa than MEZ, TIC and CAR. All five penicillins had limited activity against Acinetobacter (MIC50 less than 16 mg/l). PIP, MEZ and AZL were more active than TIC and CAR against enterococci. In a second study, the activity of PIP was evaluated by standard sensitivity tests on 4993 strains of enterobacteria, Ps. aeruginosa and Acinetobacter classified according to their phenotype of resistance to beta-lactam antibiotics. PIP was regularly active against enterobacteria and Ps. aeruginosa strains devoid of acquired resistance. The activity of PIP was significantly reduced against enterobacteria strains with a phenotype suggesting induced penicillinase production. However, the inhibition zone diameters, although reduced, remained within what is now considered the sensitivity range (notably with E. coli and Proteus spp), which raises the problem of in vitro tests interpretation. PIP was active against E. coli strains with a "cephalosporinase" phenotype, but inactive against cefotaxime resistant strains of: Enterobacter, Citrobacter and Serratia. The activity of PIP on CAR-resistant Ps. aeruginosa strains was significantly reduced, but the inhibition zone diameter in one quarter of them was still within limits of sensitivity.

[Sensitivity of Pseudomonas aeruginosa and Klebsiella spp. to ceftazidime. Current status in France]. / Sensibilité des Pseudomonas aeruginosa et des Klebsiella à la ceftazidime. Etat actuel en France.

Ceftazidime was tested against 2,224 strains of Pseudomonas aeruginosa obtained from 17 hospitals in April, May and June, 1986 and against 607 strains of Klebsiella pneumoniae and 234 strains of K. oxytoca obtained from 16 hospitals in October, 1987. The MIC's of ceftazidime against P. aeruginosa were distributed normally, with an MIC50 of 2 mg/l and an MIC90 of 4 mg/l. Depending on critical concentrations, 80 per cent of strains were sensitive, 11.4 per cent were of intermediate sensitivity and 0.54 per cent were resistant. There were few differences in results between hospitals. Ninety-two per cent of resistant strains and 45 per cent of intermediate strains (as opposed to 6 per cent of all strains) produced a high-level constitutive cephalosporinase with little variations between centres. The MIC's of ceftazidime against K. pneumoniae and K. oxytoca had a bimodal distribution: 91 per cent of strains were sensitive to 0.25 mg/l, 6 per cent of strains showed intermediate sensitivity and 3 per cent were resistant. All intermediate and resistant strains produced a very broad spectrum beta-lactamase which hydrolyzed some of the third generation cephalosporins: K. pneumoniae 36 CTX-1, 5 SHV-2, and 14 strains producing a recently identified beta-lactamase "CAZ-5/SHV-4"; K. oxytoca 3 CTX-1. These strains were isolated in 10 of the 16 hospitals which took part in the 1987 study. Comparison of these results with those of studies performed in 1984 and 1985 showed a moderate increase in the number of intermediate sensitivity strains of P. aeruginosa and the occasional occurrence, of the epidemic type, in some hospitals of Klebsiella spp. producing very broad spectrum beta-lactamases which were rare in 1985.

[The role of heavy metals and their derivatives in the selection of antibiotics resistant gram-negative rods (author's transl)]. / Rôle des métaux lourds et de leurs dérivés dans la sélection de bacillles à gram négatif résistants aux antibiotiques

The authors have studied 116 Gram-negative strains, 27 of which were sensitive to antibiotics and 89 showed multiple resistance. The MIC of mercury chloride, mercuric nitrate and of an aqueous solution of mercuresceine were much higher in the case of the sensitive strains. The transfer of resistance to mercury, which has been achieved in 56% of cases, was always accompanied by transfer of resistance to the antibiotics. The MIC of phenylmercury borate, mercurothiolic acid and other heavy metals (such as: cobaltous nitrate, silver nitrate, cadmium nitrate, nickel nitrate, zinc nitrate, copper sulphate and sodium arsenate) are approximatively the same for all strains. The normal concentrations of mercury in nature are lower than the rate of microbial selection. But in areas of accumulation, particularly in biological chains or in hospitals, the mercury compounds could play a part in the selection of antibiotic resistant Gram-negative bacteria.

[Treatment of bacterial pneumonias with cefuroxime-axetil. Predictive value of measurement of the in vitro susceptibility]. / Traitement des pneumonies bactériennes par le céfuroxime-axetil. Valeur prédictive de la mesure de la sensibilité in vitro.

Cefuroxime axetil is an oral cephalosporin with proven efficacy in adult lower respiratory tract infections. Indeed, it has a broad spectrum of activity in vitro, covering most pathogens isolated in this setting and showing good stability in the presence of betalactamases. In vitro susceptibility data are a major element in the choice of antimicrobial agent. The aim of this study was to determine the predictive value of the cefuroxime minimal inhibitory concentration (MIC) on the clinical outcome of infections treated with cefuroxime axetil. One hundred-and-seventeen (117) patients with radiologically confirmed community-acquired pneumonia of presumed bacterial origin were enrolled in a prospective multicenter trial of cefuroxime axetil therapy (500 mg twice daily). The pathogen was identified in 44 patients who were treated for a mean of 8.8 days. Most isolates were S. pneumoniae (65.9%) and H. influenzae (15.9%). The MIC was known for 35 isolates and was < or = 4 micrograms/ml in 30 cases (85.7%). The MIC value was a good predictor of clinical efficacy with a sensitivity of 100%, a specificity of 83% and a positive predictive value of 97%; the latter value indicates that therapeutic success is virtually certain when the bacterium causing pneumonia is susceptible to cefuroxime.

[Technic for assaying cefotaxime and desacetylcefotaxime in serum by high performance liquid chromatography]. / Technique de dosage du céfotaxime et du desacétyl-céfotaxime dans le sérum par chromatographie liquide haute performance.

Different high performance liquid chromatography (HPLC) methods for determination of cefotaxime (Ctx) and desacetyl cefotaxime (D-Ctx) are used. The method described presents the following advantages: a fast extraction and efficient deproteinization of serum samples are achieved with Sep-Pak cartridges; the mobile phase is a mixture of methanol - bidistilled water - acetic acid which permits the simultaneous dosage of Ctx and D-Ctx under the same chromatographic process. The retention times are respectively 7 mn 05 s and 10 mn 40 s for D-Ctx and Ctx. The results of 92 assays were compared with microbiological procedures.

[Activity of antibiotics and heavy metals against "Aeromonas" isolated from aquatic environments: phenotypic and genetic transfers (author's transl)]. / Etude de la résistance aux antibiotiques et aux métaux lourds des Aeromonas isolés des eaux usées: phénotypes de résistance et transferts génétiques.

In this study, 64% of the 197 strains of Aeromonas isolated from different stages of aquatic environment (surface water, sewage...) were resistant to one or two antibiotics, and 20% to four or more antibiotics. These multiresistant strains were only isolated from sewage and their resistances were transferable by conjugation to different species of Gram-negative bacilli. The incidence of these results is discussed.

Identification of a nonfimbrial adhesive factor of an enterotoxigenic Escherichia coli strain.

An enterotoxigenic Escherichia coli strain (strain 2230), isolated from a patient with acute infantile diarrhea, was found to adhere only to the brush border of human intestinal epithelial cells. This strain does not hemagglutinate human, bovine, chicken, or guinea pig erythrocytes. The adhesion of E. coli 2230 appears to be mediated by a nonfimbrial bacterial surface protein of 16,000 daltons which can be extracted by heating the bacteria at 60 degrees C for 20 min. This surface protein is implicated as an adhesive factor because pretreatment of enterocytes with this protein extract completely inhibits the adhesion of E. coli 2230. This adhesive factor is serologically distinct from other adhesive factors found in enterotoxigenic E. coli strains. A plasmid DNA of 66 megadaltons is involved in the synthesis of this nonfimbrial adhesive factor.

[Azithromycin: critical points]. / Azithromycine: points critiques.

The determination of the French breakpoints (< or = c, > C) were selected by the use of different criteria including bacteriological, pharmacokinetic and obviously clinical criteria. Concerning the bacteriological results, azithromycin, being an acid stable orally administered antimicrobial drug, is in vitro marginally less active than erythromycin against Gram-positive organisms including beta-haemolytic streptococci and Staphylococcus aureus. But in contrast, this azalide is more active than erytromycin against many Gram-negative pathogens, notably Neisseria gonorrhoeae, H. influenzae, Branhamella (Moraxella) catarrhalis, Ureaplasma urealyticum, and Borrelia burgdorferi. The activity of azithromycin is unaffected by the inoculum, unlike of pH, serum, and presence of CO2 for anaerobes. However, erythromycin-resistant micro-organisms are also resistant to azithromycin. Considering the pharmacokinetic criteria and the clinical results such as infections of the lower and upper respiratory tracts, skin and soft tissues, uncomplicated urethritis/cervicitis associated with N. gonorrhoeae, Chlamydia trachomatis or U. urealyticum, the preliminary breakpoints of azithromycin are defined by the following concentrations (< or = 0.12 and > 4 mg/l). Additional experimental and clinical results are required to confirm the in vitro activity against some other bacterial species (E. faecalis, L. monocytogenes, Brucella, P. multocida, or even Salmonella and Shigella).

[Comparative study of 7 cephalosporins on "Staphylococcus aureus" by the method of population analysis (author's transl)]. / Etude comparée de l'action de 7 céphalosporines sur Staphylococcus aureus par la méthode d'analyse de population.

Miscellaneous Staphylococcus aureus populations were tested with seven commercialized cephalosporins. The strains were divided in five groups according to the following criteria: penicillinase production or not: sensitivity to methicillin and cephalosporins; RB type resistance to methicillin; RH and RO type resistance to every beta-lactamine (according to Chabbert and Baudens). For each cephalosporin studied, the population cell analysis performed with these different groups showed the constant heterogeneous arrangement of the individual MIC. However, whatever the staphylococcus group, cephaloridine remains the antibiotic that inhibits the largest number of cells at lower concentration than other cephalosporins. In vitro results were compared with pharmacokinetic data of the different cephalosporins.

[The resistance of "Pseudomonas" to antibiotics and heavy metal: minimal inhibitory concentrations and genetic transfers (author's transl)]. / La résistance de Pseudomonas aux antibiotiques et aux métaux lourds: CMI et transferts

The antibiotic sensitivity of 43 strains of Pseudomonas and the minimal inhibitory concentration of mercurial derivatives (5 mineral salts and 4 organics compounds) and of silver nitrate to these microorganisms have been studied. Twelve of these strains were P. aeruginosa of hospital origin, and 31 were Pseudomonas from surface water. Resistance against these inhibitory substances let us to established some connections between the different strains. Some strains were selected to transfer resistance markers by conjugation.

[Should resistance to methicillin of RH mutant staphylococci be necessarily attributed to cephalosporins?]. / La résistance a la méthicilline des staphylocoques mutants RH doit-elle étre obligatoirement extrapolée aux céphalosporines?

The resistance to cephalosporins of 48 heterogeneous methicillin-resistant strains ("RH" mutants) of Staphylococcus pyogenes var. aureus is studied in vitro with various methods: sensitivity discs test on Mueller-Hinton medium with 5 per cent NaCl at 37 degrees C; M.I.C. in solid medium by spots medium with two inocula: a light inoculum (10(7) bacterial/ml) and a heavy inoculum (10(9) bacteria/ml). With light inoculum all strains have M.I.C. to cephaloridin less than 2 meg/ml and seem sensitive. With heavy inoculum 45 sc. equal or superior to 64 meg/ml and then are resistant. These resistances occur after 3 degrees C. The varied methods of detection of mutants to cephalosporins are discussed in this paper.