Increased incidence of Campylobacter jejuni-associated Guillain-Barré syndromes in the Greater Paris area.

The role of Campylobacter jejuni as the triggering agent of Guillain-Barré syndrome (GBS) has not been reassessed since the end of the 1990s in France. We report that the number of C. jejuni-related GBS cases increased continuously between 1996 and 2007 in the Paris region (mean annual increment: 7%, P = 0·007).

Genetic context of plasmid-carried blaCMY-2-like genes in Enterobacteriaceae.

Analysis of 15 European clinical Enterobacteriaceae isolates showed that differences in the genetic context of blaCMY-2-like genes reflected the replicon type, usually IncA/C or IncI1. These blaCMY-2 loci may originate from the same ISEcp1-mediated mobilization from the Citrobacter freundii chromosome as structures described in earlier studies.

Control of an ACC-1-producing Klebsiella pneumoniae outbreak in a physical medicine and rehabilitation unit.

This article describes an outbreak of ACC-1-producing Klebsiella pneumoniae involving 40 patients. These were mainly men under 40 years old with a spinal cord injury, in a physical medicine and rehabilitation unit. The main risk factors were prolonged hospital stay, multiple-bed rooms, tracheostomy care and assisted defaecation. The outbreak was only controlled after the introduction of rigorous patient placement (i.e. single rooms or cohorting in the same room), while allowing the patients to have free access to the various technical services (e.g. physiotherapy and occupational therapy) and living spaces necessary for re-education.

Interaction of virulent and non-virulent Rhodococcus equi human isolates with phagocytes, fibroblast- and epithelial-derived cells.

Rhodococcus equi is a facultative, intracellular, Gram-positive coccobacillus, increasingly reported in pneumonia of AIDS-infected patients. We investigated killing resistance properties of human R. equi virulent and avirulent human strains. Avirulent beta-lactam-susceptible strains had lower intracellular colony forming units after 45 min incubation in murine macrophages J774 and human monocyte-macrophage TPH-1 than those of virulent strains. Only virulent beta-lactam-resistant strains persisted within macrophages for at least 18 min only. A beta-lactam-resistant mutant was obtained from a beta-lactam-susceptible strain after selection in a penicillin G-containing culture medium. This mutant strain, like the natural virulent strains, persisted within macrophages, harboured cell-associated appendages, produced phage-like particles and induced, after its intravenous inoculation, a chronic infection in BALB/c nude mice. Supernatant culture of virulent strains transferred partial macrophage-killing resistance properties to avirulent strains. The same supernatant was toxic for L-929, HeLa and Vero cell cultures. These supernatant effects were heat-inactivated, trypsin-inactivated and did not seem to be linked to phage-like particle presence. These data argue that virulence, beta-lactam-resistance, and macrophage-killing resistance are associated in human R. equi isolates. Moreover, only virulent strains produced uncharacterized toxic factors.

[Legionnaires' disease in the Paris area: epidemiology and mortality. Apropos of a series of 81 culture-positive cases]. / Légionellose en région parisienne: épidémiologie et mortalité. A propos d'une série de 81 cas à culture positive.

OBJECTIVES: Evaluate etiological circumstances and prognosis in Legionnaires' disease. METHODS: A series of 81 culture-proven cases of Legionnaires' disease was collected in the Paris area between 1989 and 1994. RESULTS: Direct immunofluorescence assay was positive for Legionella pneumophilia in 48% of the cases. Serogroup 1 was isolated in 88% of the cases. The median age of the patients was 51 years and 74% were males. Infection was nosocomial in 28% of the cases. Immunosuppression was present in 45% of the patients (transplantation, cancer, leukemia). Among the immunosuppressed patients, 7 were HIV-infected. Mortality due to legionellosis reached 27%. This high mortality was probably related to patient selection criteria. CONCLUSION: Mortality from Legionnaires' disease remains high as confirmed in this series.

[Non-gonococcal urethritis and cervicitis. Isolation of Chlamydia trachomatis and detection of anti-Chlamydia antibodies by indirect immunofluorescence]. / Urétrites et cervicites non gonococciques. Isolement de Chlamydia trachomatis et détection des anticorps anti-chlamydiens par immunofluorescence indirecte.

The responsibility of Chlamydia trachomatis in non-gonococcal urethritis and cervicitis was investigated in 267 patients of both sexes. It was confirmed in 36.3% of patients with urethritis and 20.9% of patients with cervicitis by isolating C. trachomatis on Hela 229 cells in the presence of cytochalasin B. No clinical feature specific of C. trachomatis infection could be elicited. The patients were tested for total IgM-type serum anti-chlamydia antibodies by indirect immunofluorescence (IF), using as antigen the inclusions formed in Hela 229 cells by an L2 serotype of C. trachomatis. The serological study was also performed in 86 blood-donors used as controls. The diagnostic value of IF serology is limited in lower genito-urinary infections; the presence of specific IgM's correlates well with the isolation of C. trachomatis, but these IgM's are not detected in protracted urethritis or cervicitis. In such cases, the aetiological diagnosis can only be made by isolation of C. trachomatis from the focus of infection.

[Enterobacter cloacae and E. aerogenes septicemia: emergence of resistant variants (derepressed cephalosporinase) during treatment with third-generation cephalosporins]. / Septicémies à Enterobacter cloacae et E. aerogenes: émergence de variants résistants (céphalosporinase déréprimée) en cours de traitement par des céphalosporines de troisième génération.

From three patients hospitalised in intensive care units with Enterobacter septicaemia (two cases with E. cloacae, and one with E. aerogenes), cefotaxime therapy, alone or in combination with an aminoglycoside, selected variants (R) with increased resistance to beta-lactam antibiotics. The cross-resistance extended to all the beta-lactam antibiotics tested, penicillins and cephalosporins, including third-generation cephalosporins. The crude extracts of uninduced cultures of R variants showed high beta-lactamase activity and of the cephalosporinase type. These variants were selected in vitro with a frequency of 10(-6) to 10(-7) and may result from a mutation involving the regulation of Enterobacter cephalosporinases, usually inducible. Data from the literature indicated that this new type of resistance is actually emerging and observed not only in Enterobacter sp. The problem of emergence of R variants exhibiting cross-resistance to beta-lactam antibiotics should be considered when third-generation cephalosporins are used.

Identification of clinical coagulase-negative staphylococci, isolated in microbiology laboratories, by matrix-assisted laser desorption/ionization-time of flight mass spectrometry and two automated systems.

A study was performed to compare matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS), linked to a recently engineered microbial identification database, and two rapid identification (ID) automated systems, BD Phoenix (Becton Dickinson Diagnostic Systems, France) and VITEK-2 (bioMérieux, Marcy L'Etoile, France), for the ID of coagulase-negative staphylococci (CoNS). Two hundred and thirty-four clinical isolates of CoNS representing 20 species were analyzed. All CoNS isolates were characterized by sodA gene sequencing, allowing interpretation of the ID results obtained using the respective database of each apparatus. Overall correct ID results were obtained in 93.2%, 75.6% and 75.2% of the cases with the MALDI-TOF-MS, Phoenix and VITEK-2 systems, respectively. Mis-ID and absence of results occurred in 1.7% and 5.1% of the cases with MALDI-TOF-MS, in 23.1% and 1.3% with the Phoenix, and in 13.7% and 0.9% with the VITEK-2 systems, respectively. In addition, with the latter automate, 10.3% of the IDs were proposed with remote possibility. When excluding the CoNS species not included in the databases of at least one of the three systems, the final percentage of correct results, Mis-ID and absence of ID were 97.4%, 1.3% and 1.3% with MALDI-TOF-MS, 79%, 21% and 0% with the Phoenix, and 78.6%, 10.3% and 0.9% with the VITEK-2 system, respectively. The present study demonstrates the robustness and high sensitivity of our microbial identification database used with MALDI-TOF-MS technology. This approach represents a powerful tool for the fast ID of clinical CoNS isolates.

Genetic environment of acquired bla(ACC-1) beta-lactamase gene in Enterobacteriaceae isolates.

We studied the genetic organization of bla(ACC-1) in 14 isolates of Enterobacteriaceae from France, Tunisia, and Germany. In a common ancestor, ISEcp1 was likely involved in the mobilization of this gene from the Hafnia alvei chromosome to a plasmid. Other genetic events involving insertion sequences (particularly IS26), transposons (particularly Tn1696), or sulI-type integrons have occurred, leading to complex genetic environments.

In-vitro antimicrobial susceptibility of Rhodococcus equi.

Rhodococcus equi is an intracellular facultative, Gram-positive cocco-bacillary organism of increasing importance as a pulmonary pathogen in HIV-positive patients. This study was carried out to evaluate the optimal antibiotic combinations for treating such infections. Four human R. equi isolates and one reference strain were tested for their susceptibilities to 36 antibiotics. In-vitro the most active antibiotics were amikacin, gentamicin, netilmicin, erythromycin, clarithromycin, roxithromycin, ciprofloxacin, sparfloxacin, rifampicin, vancomycin, teicoplanin, doxycycline, minocycline, imipenem, meropenem and trimethoprim/sulphamethoxazole. The only bactericidal antibiotics were the aminoglycosides, ciprofloxacin, sparfloxacin and vancomycin. As determined by FIC indices, four combinations were synergistic: rifampicin-erythromycin, rifampicin-minocycline, erythromycin-minocycline and imipenem-amikacin. However, no antibiotic combinations were synergistic with the time-kill kinetic method at achievable serum concentrations or at ten-fold and half-fold the MICs. Frequencies of selection of antibiotic-resistant mutants determined at concentrations of five- and ten-fold the MICs ranged from less than 1 x 10(-8) for erythromycin and trimethoprim/sulphamethoxazole to 5 x 10(-4) for amikacin. These results may be of help in selecting the antibiotics for treating infected HIV-positive patients.

[Comparative in vitro antistaphylococcal effect of norfloxacin and pefloxacin on 312 hospital strains]. / Activité antistaphylococcique comparée in vitro de la norfloxacine et de la péfloxacine sur 312 souches hospitaliéres.

Antistaphylococcal activity of two new quinolones, norfloxacin and pefloxacin, was studied. Minimal inhibitory concentrations (MICs) were determined by the agar dilution technique for 312 staphylococcal strains, all of which were resistant to nalidixic acid. 50% and 90% MICs were respectively 1 and 4 micrograms/ml for norfloxacin and 0.5 and 1 micrograms/ml for pefloxacin. Activities of these two new quinolones proved similar on Staphylococcus aureus and non-coagulase-producing staphylococci, regardless of their response to methicillin. Cross resistance between the two drugs was demonstrated.

Host response to infection with a temperature-sensitive mutant of Salmonella typhimurium in a susceptible and a resistant strain of mice.

The inoculation of a temperature-sensitive mutant of Salmonella typhimurium induced a long-lasting infection in susceptible (C57BL/6) and resistant (A/J) mice. During week 1 of infection, the number of bacteria in the spleens was similar in both mouse strains. Then, the decrease of bacteria was more rapid in the resistant strain. Splenomegaly and granulomatous hepatitis were more severe in the susceptible strain. The immune response induced by this infection was studied. In both mouse strains delayed-type hypersensitivity to Salmonella antigens was present, and resistance to reinfection with a virulent strain of S. typhimurium or with Listeria monocytogenes appeared with the same kinetics. Thus, it does not seem that the gene(s) controlling natural resistance to S. typhimurium act(s) on acquired immunity.

[In vitro sensitivity at 18 antibiotics of 192 strains of Pseudomonas aeruginosa isolated at Garches Hospital]. / Sensibilité in vitro à dix-huit antibiotiques de 192 souches de Pseudomonas aeruginosa isolées à l'hôpital de Garches.

The in vitro activity of 18 antibiotic (beta-lactam agents, quinolones and aminoglycoside has been evaluated against 192 clinical isolates of Pseudomonas aeruginosa. Minimal inhibitor concentrations (MICs) were determined by the agar dilution technique. The 50% and 90% MICs were respectively: ticarcillin (32/greater than 1 024), azlocillin (16/512), piperacillin (8/512), cefsulodin (4/128), ceftazidime (2/8), aztreonam (4/16), imipenem (2/4), nalidixic acid (128/256), pefloxacin (1/8), norfloxacin (1/8), ofloxacin (2/8), ciprofloxacin (0.25/2), gentamicin (8/256), sisomicin (4/256), tobramycin (2/128) dibekacin (4/256), netilmicin (16/256), amikacin (8/16). The sensitivity to beta-lactam agents and to quinolones was usual. Resistance to aminoglycosides was frequently observed (59%): 35.7% of the resistant isolates were resistant to gentamicin-sisomicin-tobramycin-dibekacin-netilmicin, 30% to netilmicin alone, 17.8% to gentamicin-sisomicin-tobramycin-dibekacin-netilmicin-amikacin, 7% to gentamicin-netilmicin, 5.3% to gentamicin-sisomicin-tobramycin-dibekacin; we did not find any P. aeruginosa resistant only to gentamicin or gentamicin-sisomicin.

[Comparative activity of cefepime, ceftazidime and imipenem in a mouse infection caused by Klebsiella pneumoniae producing a broad spectrum beta-lactamase]. / Activité comparée du céfépime, de la ceftazidime et de l'imipénème lors d'une infection de la souris par Klebsiella pneumoniae productrice de beta-lactamase à spectre élargi.

Mice experimentally infected with extended-spectrum beta-lactamase-producing Klebsiella pneumoniae strains were injected twice daily for three days with ceftazidime, cefepime, or imipenem (25, 50, or 100 mg/kg/injection). Treatment efficacy was based on five-day survival and on the spleen viable bacteria count 16 hours after the last treatment dose. Under these experimental conditions, ceftazidime showed some activity on strains with low levels of resistance to ceftazidime. Cefepime used in a dose of 50 or 100 mg per injection demonstrated good activity but was slightly less effective than imipenem.

Role of T-lymphocyte subsets in Rhodococcus equi infection.

Rhodococcus equi, a facultative intracellular gram-positive bacterium, can induce life-threatening infections in immunocompromised patients, especially those with AIDS. We have studied the mechanism of acquired immunity to this pathogen in a murine model. Protective immunity was induced by live but not killed bacteria. Adoptive transfer of resistance was obtained with spleen cells but not immune serum from mice immunized intravenously 30 days earlier with live bacteria. In normal mice, an intravenous challenge of 5 x 10(6) CFU of R. equi was cleared from the spleen, liver, and lungs within 3 weeks, whereas athymic nude mice were unable to clear the bacteria. In vivo depletion with monoclonal antibodies showed that both CD4+ and CD8+ T-cell subsets participate in the clearance of bacteria and that CD8+ T cells play the major role.

Involvement of interferon-gamma and tumor necrosis factor-alpha in host defense against Rhodococcus equi.

Rhodococcus equi is a facultative, intracellular, gram-positive coccobacillus increasingly reported as an opportunistic pathogen in AIDS patients. In vitro, splenic cells of noninfected euthymic mice produced tumor necrosis factor-alpha (TNF alpha) in greater amounts when incubated with live R. equi rather than with killed bacteria. In vivo, interferon-gamma (IFN-gamma) and TNF alpha serum levels of infected euthymic mice remained below the level of detectability. Treatment of infected nude mice, which developed chronic infection, with discontinuous injections of IFN-gamma, TNF alpha, or both did not decrease bacterial colony-forming units in liver, spleen, or lungs. However, treatment of infected euthymic mice, which cured a R. equi inoculum within 3 weeks, with anti-IFN-gamma or anti-TNF alpha antibodies (or both) significantly increased tissue colony counts. These data argue that, in this murine model, endogenous IFN-gamma and TNF alpha are involved in the cell-mediated immunologic response against R. equi infection.

Influence of different regions of the H-2 complex on the rate of clearance of Salmonella typhimurium.

The rate of clearance of Salmonella typhimurium from the mouse spleen is under H-2 linked genetic control. The results of the present study, with H-2 recombinant mice on a C57BL/10 background, suggest the involvement of at least two loci, one in the D region and the other in the K-A alpha chromosomal segment.