1,720,972 research outputs found
Antimicrobial resistance among non-fermentative gram-negative bacilli isolated from the respiratory tracts of Italian inpatients: A 3-year surveillance study by the Italian Epidemiological Survey
No full textThe Italian Epidemiological Survey evaluated antibiotic susceptibility of non-fermentative Gram-negative bacilli isolated from inpatient respiratory-tract specimens collected throughout Italy during 1997-1999. The minimal inhibitory concentrations of 14 antibiotics for 1474 Pseudomonas aeruginosa strains, 307 Stenotrophomonas maltophilia strains and 114 Acinetobacter baumannii strains were determined in 57 clinical microbiology laboratories by means of a standardised micro-dilution method. The most active drugs against P. aeruginosa isolates were meropenem (81% susceptible) and amikacin (80% susceptible). Imipenem and meropenem proved to be the only agents active against A. baumannii isolates, although 13 and 16%, respectively, of strains were resistant to these drugs. Trimethoprim-sulphamethoxazole (TMP-SMZ) showed activity only against S. maltophilia isolates (83% susceptible). A total of 185 multidrug-resistant P. aeruginosa isolates (resistant to piperacillin, ceftazidime, gentamicin, and imipenem) were found. Resistance rates and trends showed consistent regional variations, including sharp increases from 1997 to 1999 in imipenem resistance among P. aeruginosa isolates from central and southern Italy
Isolation and identification of Mycobacterium neoaurum from a patient with urinary infection
No full textMycobacterium neoaurum is a novel species of Mycobacteria, until now only isolated from catheters in immunosuppressed patients. This report describes the isolation and identification of M. neoaurum from urine obtained from a hospitalized patient
Evaluation of the Abbott LCx Mycobacterium tuberculosis assay in comparison with culture methods in selected Italian patients
No full textA ligase chain reaction (LCR) DNA amplification method for the molecular diagnosis of Mycobacterium tuberculosis (Abbott LCx MTB) was evaluated in comparison with solid and liquid phase culture on 622 selected samples collected in two large Italian hospitals, of which 310 obtained from HIV-1 positive patients and 312 from HIV-negative individuals. The overall prevalence of mycobacteria by culture was 22% (137/622), and the apparent sensitivity and specificity of LCx vs. culture were 87.6% and 98.2%. Of the 26 culture positive/LCx negative samples, 22 were positive for MOTT and 4 for M. tuberculosis. All 9 samples positive by LCx and negative by culture were classified as true positive by clinical criteria. The final values of sensitivity, specificity, positive predictive value and negative predictive value for LCx rose to 96.8%, 100%, 100% and 99.2%, respectively. The adjusted sensitivity of culture methods was 89.5% for solid phase and 92.7% for Bactec. In view of the high sensitivity on both smear-positive (100%) and smear-negative (92.4%) samples and of the high negative predictive value, the LCR-based amplification method appears suitable as a routine screening method for the rapid diagnosis of M. tuberculosis in high-risk patients
Changes in incidence and risk factors of Mycobacterium avium complex infections in patients with AIDS in the era of new antiretroviral therapies
No full textThe aim of the study presented here was to determine the incidence, risk factors and prognostic indicators of Mycobacterium avium complex (MAC) infection in HIV-infected subjects prior to and after the introduction of highly active antiretroviral therapy (HAART). In the HAART era, the incidence of MAC infection decreased significantly from 3.7 to 0.9 per 100 person-years. Using logistic regression analysis, a high acute physiology and chronic health evaluation (APACHE) III score, a low number of CD4+ cells/ mm3 and a high level of HIV viremia were found to be independent predictors of the risk to develop MAC disease; however, a high APACHE III score was the only prognostic indicator associated with an unfavourable outcome of a disseminated MAC infection. These results indicate that MAC infections, although considerably less frequent in the HAART era, are still responsible for cases of severe disease
Polymerase chain reaction-reverse cross-blot hybridization assay in the diagnosis of sporotrichoid Mycobacterium marinum infection
No full textIn this paper, we report a patient in whom Mycobacterium marinum sporotrichoid infection was diagnosed using polymerase chain reaction (PCR) amplification of the 16S rRNA gene and subsequent analysis of the amplified product in a reverse cross-blot hybridization assay with mycobacterial species-specific probes. This molecular method allowed us rapidly to detect and identify this organism directly in the patient's lesional skin biopsy rather than in cultures in conventional media. The identification provided by PCR-reverse cross-blot hybridization assay was confirmed by examination of the morphological and biochemical features and by high-performance liquid chromatography analysis of mycolic acid from the clinical isolate, suggesting the validity of our molecular approach
First case of Tsukamurella pulmonis infection in an immunocompetent patient
No full textWe report a case of pneumonia due to Tsukamurella pulmonis in a 76-year-old immunocompetent woman with chronic pulmonary disease. Microbiological diagnosis was made by bacteriological and molecular means and infection was cured by empirical antibiotic treatment. This work highlights the potential role of Tsukamurella in pathogenesis of pneumonia in immunocompetent patients
Recurrent upper airway infections and bacterial biofilms.
No full textBackground: Bacterial biofilms identified in various medical devices used in otorhinolaryngology, including tympanostomy tubes, voice prostheses, and cochlear implants, can directly colonise mucosal tissues. The upper airways seem to be at high risk for this type of colonisation. Chronic and/or recurrent upper airway infections may be related to the complex structural and biochemical (quorum sensing) organisation of the biofilm which interferes with the activity of antibiotics (including those with proven in vitro efficacy), thus promoting the establishment of a chronic infection eradicable only by surgical treatment. Biofilm formation plays a role in upper respiratory infections: it not only explains the resistance of these infections to antibiotic therapy but it also represents an important element that contributes to the maintenance of a chronic inflammatory reaction.Objectives: To document the presence of biofilms in surgical tissue specimens from patients with recurrent infection diseases, and identify their possible role in the chronicity of these infectious processes.Method: We examined 32 surgical specimens from the upper respiratory tract (tonsils, adenoids, mucosa from the ethmoid and maxillary sinuses) of 28 patients (20 adults, eight children) with upper airway infections that had persisted despite repeated treatment with anti-inflammatory agents and antibiotics with demonstrated in vitro efficacy. Tissues were cultured using conventional methods and subjected to scanning electron microscopy for detection of biofilm formation.Results: Over 80 per cent (26/32; 81.3 per cent) of the tissue specimens were culture-positive. Bacterial biofilms (associated in most cases with coccoid bacteria) were observed in 65.6 per cent of the tissue samples
Routine use of PCR-reverse cross-blot hybridization assay for rapid identification of Mycobacterium species growing in liquid media
No full textA PCR-reverse cross-blot hybridization assay procedure that is able to rapidly identify 13 species of clinically relevant mycobacteria was evaluated for routine use in the identification of acid-fast isolates growing in BACTEC 460 TB (12B and 13A) and BACTEC 9000 MB (Myco/F) liquid media. Eight of the probes used were already described by Kox et al. (L. F. F. Kox et al., J. Clin. Microbiol. 33:3225-3233, 1995). In addition, we used six other probes specific for M. chelonae, M. malmoense or M. szulgai, M. genavense, M. gordonae, M. terrae, and M. marinum/M. ulcerans that we designed ourselves. This procedure allowed us to identify 459 mycobacterial species directly from broth cultures of 5,466 clinical samples collected over 1 year and processed with the radiometric or nonradiometric BACTEC system. Our results were in agreement with those obtained by conventional identification methods and also with those obtained by mycolic acid analysis by high-performance liquid chromatography. This assay seems to be a reliable procedure for the routine identification of mycobacteria, providing an accurate identification of mycobacterial isolates more rapidly than conventional tests, with remarkable implications for an efficacious specific antimycobacterial therapy
Use of microelectronic array technology for rapid identification of clinically relevant mycobacteria
No full textWe developed a new method based on the Nanochip microelectronic array technology for identification of various clinically relevant mycobacterial species. PCR-amplified rRNA genes obtained from 270 positive Mycobacteria Growth Indicator Tube cultures were successfully tested by hybridizing them with species-selective probes, and the results agreed with those of conventional identification methods. The system is rapid and accurate and opens new perspectives in clinical diagnostics
Evaluation of a nonradiometric system (BACTEC 9000 MB) for detection of mycobacteria in human clinical samples
No full textThis study was carried out to evaluate the rate of recovery and time required for detection of mycobacteria from pulmonary and extrapulmonary human clinical samples, by using a fluorescence-quenching-based oxygen sensor (BACTEC 9000 MB; Becton Dickinson Microbiology Systems, Sparks, Md.). The results were compared with those obtained by microscopy, conventional culture in Lowenstein-Jensen (LJ) medium, and a BACTEC radiometric system (BACTEC 460 TB; Becton Dickinson). Of the 779 clinical samples processed, 364 from pulmonary sites and 415 from extrapulmonary sites, 62 (7.9%) were positive for mycobacterial isolates; of the positive samples, 59 (95.1%) were detected with the fluorescent BACTEC 9000 MB system, 57 (91.9%) were detected with the radiometric system (BACTEC 460 TB), and 43 (69.3%) were detected with LJ conventional culture. The mean times to detection of all mycobacteria with BACTEC 9000 MB and BACTEC 460 TB were similar (10.3 and 10.0 days, respectively). The results obtained indicate that the nonradiometric BACTEC (BACTEC 9000 MB) system is as efficient as Bactec 460 TB and significantly more efficient than LJ for the rapid recovery of mycobacteria from both pulmonary and extrapulmonary clinical specimens. Though the BACTEC 9000 MB system is recommended for respiratory specimens, we demonstrated that it can be successfully used also for recovery of mycobacteria from clinical specimens from various extrapulmonary sites
- …
