Biofilm demolition and antibiotic treatment to eradicate resistant Helicobacter pylori: a clinical trial.

BACKGROUND & AIMS: Helicobacter pylori attaches to gastric mucosa and grows as a biofilm. This constitutes protection from antimicrobial agents. We assessed the role of a pretreatment with n-acetylcysteine in destroying biofilm and overcoming H pylori antibiotic resistance. METHODS: In an open-label, randomized controlled trial, 40 subjects with a history of at least 4 H pylori eradication failures were evaluated for biofilm presence, antibiotic susceptibility, and H pylori genotypes. Subjects were assigned randomly to receive (group A) or not (group B) n-acetylcysteine before a culture-guided antibiotic regimen. The primary end point was the H pylori eradication rate as assessed by (13)C-labeled urea breath testing. RESULTS: H pylori was eradicated in 13 of 20 (both per-protocol and intention-to-treat analyses, 65%; 95% confidence interval, 44%-86%) group A participants and 4 of 20 (both per-protocol and intention-to-treat analyses, 20%; 95% confidence interval, 3%-37%) group B participants (P < .01). Biofilms persisted only in unsuccessfully treated participants. H pylori genotypes did not influence treatment outcome. CONCLUSIONS: N-acetylcysteine pretreatment before a culture-guided antibiotic regimen is effective in overcoming H pylori antibiotic resistance.

[An integrated model for the evaluation and risk management of tuberculosis infection and active tuberculosis in homeless people in the city of Rome (Italy)]. / Un modello integrato di valutazione e gestione del rischio di Infezione Tubercolare e di Tubercolosi attiva negli homeless nella città di Roma.

In this article we describe an integrated model for the evaluation and risk management of tuberculosis (TB) infection and active TB in socially disadvantaged populations in the city of Rome. We describe and discuss the clinical evaluation procedures performed and the data collection forms used; these tools are useful for the epidemiologic surveillance and clinical management of patients, particularly high risk patients such as the homeless.

Damage to ciliated epithelium in chronic rhinosinusitis: what is the role of bacterial biofilms?

OBJECTIVES: We assess the association between the presence of biofilms and cilial damage in patients with chronic rhinosinusitis (CRS), describe the microorganisms associated with samples that exhibited cilial loss and biofilms, and demonstrate the absence of ciliary injury and biofilms in similarly prepared "normal" controls. METHODS: We examined samples of ethmoid mucosa obtained from 24 patients who underwent functional endoscopic sinus surgery for CRS. Samples from a control group (20 healthy subjects) were also examined. The specimens were divided into 2 fragments; the first was processed for bacterial cultures, and the second was subjected to scanning electron microscopy. Statistical analysis was performed. RESULTS: All CRS samples had positive bacterial cultures. The scanning electron microscopy analysis showed bacterial biofilms in 10 of the 24 specimens. A marked destruction of the epithelium was observed in samples positive for biofilms (p < 0.001), and the presence of Haemophilus influenzae was associated with ciliary abnormalities (partial damage in 55.6% and absence of cilia in 50%; p = 0.041). CONCLUSIONS: The high percentage of biofilms in our specimens confirms the association between biofilms and CRS. Our data support the hypothesis that biofilm formation represents the latter phase of an inflammatory process that leads to complete epithelial destruction.

Use of microelectronic array technology for rapid identification of clinically relevant mycobacteria.

We 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.

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.

The 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.

Early detection of negative BACTEC MGIT 960 cultures by PCR-reverse cross-blot hybridization assay.

We evaluated the efficacy of a PCR-reverse cross-blot hybridization assay, a test which permits identification of mycobacteria by means of species-specific probes and a Mycobacterium-specific probe, for early detection of negative BACTEC MGIT 960 mycobacterial cultures. Aliquots of 549 cultures were collected 7 days after the culture media were inoculated with various clinical specimens and tested with the molecular assay. PCR results were compared to those obtained at the end times with the BACTEC MGIT 960 system. Of the 549 specimens analyzed, 484 were found to be negative and 64 were found positive by both methods; one specimen, found to be positive by the BACTEC MGIT 960 system, was identified as negative by the molecular assay. In view of its high negative predictive value (99.8%), the PCR-reverse cross-blot hybridization assay appears to be a valid tool for early detection of negative BACTEC MGIT 960 cultures.