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Biomedical subjects

J Croize

Publications and source records attributed to J Croize.

At least 19 recordsLinked to original sources

[Acute Salmonella typhi meningitis in a 25-day-old newborn infant complicated by obstruction of the sylvian artery].

UNLABELLED: Acute Salmonella typhi meningitis is rare in neonates, mostly reported from developing countries with poor socioeconomic conditions. CASE REPORT: A male Caucasian newborn presented with acute Salmonella typhi meningitis at the age of 25 days. His parents had traveled across several African countries under rudimentary hygienic conditions a few months before his birth. Despite early and adapted antibiotic therapy (cefotaxime plus netilmycine), the child developed ischemia in the region of the left sylvian artery. CONCLUSION: Salmonella meningitis must be considered while dealing with a sick newborn whose mother has traveled across countries with endemic typhoid.

Brain Ischemia↗

Pseudomonas aeruginosa cystic fibrosis isolates induce rapid, type III secretion-dependent, but ExoU-independent, oncosis of macrophages and polymorphonuclear neutrophils.

Pseudomonas aeruginosa, an opportunistic pathogen responsible most notably for severe infections in cystic fibrosis (CF) patients, utilizes the type III secretion system for eukaryotic cell intoxication. The CF clinical isolate CHA shows toxicity towards human polymorphonuclear neutrophils (PMNs) which is dependent on the type III secretion system but independent of the cytotoxin ExoU. In the present study, the cytotoxicity of this strain toward human and murine macrophages was demonstrated. In low-multiplicity infections (multiplicity of infection, 10), approximately 40% of the cells die within 60 min. Analysis of CHA-infected cells by transmission electron microscopy, DNA fragmentation assay, and Hoechst staining revealed the hallmarks of oncosis: cellular and nuclear swelling, disintegration of the plasma membrane, and absence of DNA fragmentation. A panel of 29 P. aeruginosa CF isolates was screened for type III system genotype, protein secretion profile, and cytotoxicity toward PMNs and macrophages. This study showed that six CF isolates were able to induce rapid ExoU-independent oncosis on phagocyte cells.

ADP Ribose Transferases↗

[Experience with an "isolation unit" for patients infected with multi-resistant bacteria. Retrospective study of 49 patients].

OBJECTIVES: Perform a retrospective analysis of care in a hospital "isolation unit" for patients infected with multirestant bacteria (MRB), i.e. meticillin-resistant staphylococcus aureus (SAMR), broad spectrum beta-lactamase secreting enterobacteria. (BLSE). PATIENTS AND METHODS: Forty-nine patients infected with MRB were cared for in our hospital isolation unit between January 1, 1996 and January 1, 1997. Each patient was in a separate room equipped with a sink and soap distributor, single-use towels, and individual material for patient care (stethoscope, mobile equipment, writing material, etc.). The personnel were given special training in the prevention of nosocomial infections. At admission, and in all patients, bacteriological samples to search for SAMR were acquired from nasal discharge, urine, perineal swabs, wounds and bed sores. Wound, urine and fecal samples were also taken to search for BLSE. Search for other sites of infection depended on the clinical situation. The management protocol in the isolation unit included: isolation, daily antiseptic baths, topical application of antibiotics or antiseptics on all bacteriologically proven sites of SAMR infection, selective decontamination of the digestive tract for patients with BLSE positive stools. Systemic antibiotics were given case by case. RESULTS: Mean duration of stay in the isolation unit was 17 days for SAMR infections and 14 days for BLSE infections. Mean delay to sterilization of the infected sites varied depending on the localization: 2.3 days for blood and 19.4 days for stools. Seven patients died. After leaving the isolation unit, the bacteriological course was followed in 23 patients: there were 7 cases of recurrence at least one site within a mean delay of 34.5 days. CONCLUSION: Use of isolation units provides an interesting solution for health care centers to control spread of multiresistant bacteria. Considering the endemic state of multiresistant bacteria infections in French hospitals, each health care unit should have correctly equipped facilities for isolating infected patients.

Drug Resistance, Microbial↗

[Bacterial contamination of multi-dose ocular solutions. A prospective study at the Grenoble Teaching Hospital].

The bacterial contamination rate of multidose ocular solutions used by hospitalized patients was evaluated by culturing vial dropper tips and residual solution in vials. Bacterial colonies were counted and identified. Overall 39 (23.5%) selected vials were contaminated. Contamination rates were 17.7% (20/113) for vials used by ophthalmology ward patients and 35.8% (19/53) for vials used by internal medicine and gerontology patients (P < 0.02). The most commonly identified organisms were part of the normal commensal flora. Three ophthalmology patients were using vials contaminated with Pseudomonas aeruginosa. A significant (P < 0.01) positive correlation was found between vial contamination rate and duration of vial use. Vials containing an antimicrobial agent were less likely to be contaminated than vials without antimicrobials (P < 0.01). No clinical consequences of vial contamination were identified. However, ocular solution vial contamination carries a risk of infection. Our data are evidence of inadequate efficacy of preservatives present in ocular solutions. The standard practice of using ocular solution vials for seven days in health care facilities may need to be reappraised. Care should be taken to ensure that health care providers and patients understand the rules for ocular solution use. Unit-dose presentations may be preferable over multi-dose presentations for in hospital treatment.

Anti-Bacterial Agents↗

A complex mutant of TEM-1 beta-lactamase with mutations encountered in both IRT-4 and extended-spectrum TEM-15, produced by an Escherichia coli clinical isolate.

Escherichia coli GR102 was isolated from feces of a leukemic patient. It expressed different levels of resistance to amoxicillin or ticarcillin plus clavulanate and to the various cephalosporins tested. The double-disk synergy test was weakly positive. Production of a beta-lactamase with a pI of 5.6 was transferred to E. coli HB101 by conjugation. The nucleotide sequence was determined by direct sequencing of the amplification products obtained by PCR performed with TEM gene primers. This enzyme differed from TEM-1 (blaT-1B gene) by four amino acid substitutions: Met-->Leu-69, Glu-->Lys-104, Gly-->Ser-238 and Asn-->Asp-276. The amino acid susbstitutions Leu-69 and Asp-276 are known to be responsible for inhibitor resistance of the IRT-4 mutant, as are Lys-104 and Ser-238 substitutions for hydrolytic activity of the extended-spectrum beta-lactamases TEM-15, TEM-4, and TEM-3. These combined mutations led to a mutant enzyme which conferred a level of resistance to coamoxiclav (MIC, 64 microg/ml) much lower than that conferred by IRT-4 (MIC, 2,048 microg/ml) but higher than that conferred by TEM-15 or TEM-1 (MIC, 16 microg/ml). In addition, the MIC of ceftazidime for E. coli transconjugant GR202 (1 microg/ml) was lower than that for E. coli TEM-15 (16 microg/ml) and higher than that for E. coli IRT-4 or TEM-1 (0.06 microg/ml). The MICs observed for this TEM-type enzyme were related to the kinetic constants Km and k(cat) and the 50% inhibitory concentration, which were intermediate between those observed for IRT-4 and TEM-15. In conclusion, this new type of complex mutant derived from TEM-1 (CMT-1) is able to confer resistance at a very low level to inhibitors and at a low level to extended-spectrum cephalosporins. CMT-1 received the designation TEM-50.

Anti-Bacterial Agents↗

Bacteria Are Omnipresent on Phanerochaete chrysosporium Burdsall.

Bacteria have been isolated from 10 different strains of Phanerochaete chrysosporium, a white rot fungus which degrades lignocellulosic materials. The investigations showed that one or more bacterial species were always associated with the fungus. Various attempts to eliminate the bacteria on the fungus were unsuccessful. Three different bacterial species were isolated and identified. One of these was Agrobacterium radiobacter, while another may represent a new taxon close to the genus Burkholderia. A third strain remains unidentified but is most probably a member of rRNA superfamily IV or the Woese (alpha) group. Besides P. chrysosporium, 23 other white rot fungi and 9 brown rot fungi were also investigated. None of these was associated with bacteria. The physiological significance of the association between the fungus and the bacteria remains to be elucidated.

Journal Article↗

[Mechanism of antibiotic resistance in bacteria responsible for respiratory infections].

Bacterial resistance is both a frequent phenomena and in perpetual evolution; currently it effects all antibiotics. The acquisition of resistance is a result of chromosomal mutations or is a contribution of genetic material either as plasmids or transposons. The principle mechanisms which can be isolated or associated can be grouped together under changes of bacterial permeability which alters the target of the anti-infectious agents; or the synthesis of enzymes which inhibit the activity of the antibiotic. Some micro-organisms such as Staphylococcal aureus, Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas aeruginosa, and certain enterobacteria have developed resistance to varying degrees against the antibiotics initially or more recently introduced which pose, in some cases, very real therapeutic problems. The prescribing doctor should recognise the principle bacterial phenotypes which are resistant, as well as the rules of association of the different antibiotics in order to institute an effective anti-infectious regime, which allows the cure of the patient and limits any introduction of resistance or the selection of resistant mutants.

Bacteria↗

[Neuromeningeal listeriosis in adults. Clinical aspects and contribution of cotrimoxazole in monotherapy].

A series of 28 patients suffering from neuromeningeal listeriosis is reported. This disease is consecutive to infection by Listeria monocytogenes--an ubiquitous and opportunistic Gram-positive bacillus--and has become a public health problem: its incidence is increasing and its prognosis is very severe despite the development of new bacteriological identification methods. Human beings are contaminated by food, which explains the frequent outbreaks of epidemics which are widely publicized, the infection being one of the consequences of the unprecedented development of the food industry and the cold food chain. The predominant clinical picture is one of non-specific meningoencephalitis. In about 50 percent of the cases the subjects infected are "immunodepressed" and/or more than 60 years' old. The diagnosis is difficult since the bacteriological identification is delayed (direct examination of the cerebrospinal fluid is rarely positive) and this fluid may be sterile (hence the value of blood cultures). A probability treatment therefore must be initiated before the diagnosis is confirmed if an unfavourable outcome is to be avoided. In Listeria monocytogenes infection cotrimoxazole administered alone seems to be a better antibacterial therapy than the reference ampicillin-aminoside combination.

Adolescent↗

Activation of the human complement alternative pathway by Listeria monocytogenes: evidence for direct binding and proteolysis of the C3 component on bacteria.

The capacity of the intracellular pathogen Listeria monocytogenes to activate the alternative pathway of human complement was examined. Incubation of L. monocytogenes with human serum in optimal conditions (20% Mg2+EGTA [ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid]-chelated serum) consumed (31.3 +/- 3.9)% of C3 hemolytic activity and led to similar amounts of C3 deposition among the 27 strains tested, except for a rough mutant and the penicillin-induced L forms of strain EGD, which bound reduced amounts of C3. The same results were obtained with strains belonging to related species (L. innocua, L. seeligeri, L. welshimeri, and L. ivanovii). Direct evidence is provided that L. monocytogenes induces the deposition of C3b and its cleavage products iC3b and C3d through ester and amide linkages, as demonstrated by the analysis of the released products of radiolabelled purified C3 after treatment with hydroxylamine. Our results clearly demonstrate that L. monocytogenes activates the alternative pathway of human complement, suggesting that bacteria in the blood or in tissues of infected patients are opsonized and targeted to C3 receptor-bearing cells such as macrophages.

Cell Membrane↗

Improved identification of Staphylococcus aureus using a new agglutination test. Results of an international study.

A new reagent for the identification of Staphylococcus aureus, SLIDEX STAPH-KIT, operates on the principle of a latex and red blood cell combination agglutination: red blood cells are coated with fibrinogen for the detection of clumping factor, and latex particles are sensitized with anti-S. aureus serotype 18 monoclonal antibody for the detection of protein A and antigen 18. French strains belonging to serotype 18 are methicillin-resistant. The performance of this reagent was compared with STAPHYSLIDE and STAPHAUREX in Europe (France, Germany, Italy), in the United States and in Japan using 548 methicillin-resistant S. aureus strains, 392 methicillin-sensitive S. aureus strains, and 441 non-aureus staphylococci. The specificity of the three reagents was equivalent (98.8% for SLIDEX STAPH-KIT, 99.1% for STAPHYSLIDE, 98.1% for STAPHAUREX). SLIDEX STAPH-KIT (97.3%) was more sensitive than STAPHYSLIDE (93.5%) and STAPHAUREX (89.7%) for all S. aureus strains due to a higher rate of identified methicillin-resistant S. aureus strains.

Agglutination Tests↗

[Hepatic abscess due to Yersinia in a child with thalassemia].

A 15-year-old boy with thalassaemia major treated with desferrioxamine, experienced fever associated with digestive disorders. These symptoms led to the discovery of multiple liver abscesses. Therapy included antibiotics (third generation cephalosporin and aminoglycoside) and desferrioxamine discontinuation. Recovery occurred within one month approximately. Systemic yersiniosis was further confirmed by the finding of antibodies to Yersinia enterocolitica O5. The systemic diffusion of Yersinia is favoured by iron-overload and iron-chelating agents.

Adolescent↗

[Detection of extended-spectrum beta-lactamases by the rapid ATB E technique. Value of the API V2.1.1 expert system].

Twenty-two extended-spectrum betalactamase-producing strains of enterobacteriaceae recovered in the authors' hospital were tested using the Rapid ATB E coupled with the API V2.1.1. expert system. The expert system detected 90.9% of ESBL-producing strains. Two strains producing a SHV2 and a CTX1, respectively, escaped detection by the expert system despite concomitant resistance to aminoglycosides.

4-Quinolones↗

[Evaluation of a DNA probe test for the detection of Legionella SPP].

Seventeen suspension of Legionella pneumophila and ten of Legionella bozemanii in saline or bronchoalveolar lavage (BAL) fluid were tested using the Gen Probe technique. The detection threshold was found to be 10(3)-10(4) CFU/ml. Specificity and sensitivity were evaluated by using the probe on 8 suspensions of bacteria other than Legionella and by performing a comparative study of the probe test, direct immunofluorescence and culture with 103 specimens (BAL fluid in most instances) from 92 patients with possible legionellosis. Sensitivity was found to be acceptable (3 of the 4 culture-positive specimens were positive by the probe test) and specificity was 100% despite the fact that most (80/99) BAL specimens were not sterile and regardless of the cutoff level used to define positivity. The advantages of the DNA probe test, including rapidity, simplicity and objectivity, should be weighed against its disadvantage, i.e., only acceptable sensitivity and use of radioactivity.

DNA Probes↗