DBD-FISH, an effective marker for detecting genotoxicity in buccal mucosa exfoliated cells of patients with oral cancer.

Oral squamous cell carcinoma (OSCC) is characterized by increased genetic instability as an essential variable of event of neoplastic transformation. The aim of this study was to evaluate genomic instability in exfoliated cells from the buccal mucosa of patients with OSCC vs. the control group, using DNA Breakage Detection/Fluorescence In Situ hybridization (DBD-FISH). Exfoliated cells from the buccal mucosa were obtained from 38 patients with oral cancer (case group) and from 10 individuals without oral lesions (control group). DNA damage was evaluated by DBD-FISH using the whole-genome DNA probe and digital imaging analysis. Collaterally, HPV infection was determined utilizing the INNO-LiPA HPV kit. Patients with OSCC showed an increase in the hybridization signal five times more intense than that of the baseline level of DNA damage detected in control individuals. The best cutoff value for predicting oral squamous cell carcinoma was 67.46, and an Odds Ratio (OR) value of 87. HPV detection analysis revealed than one patient with OSCC (2.6%) was positive for HPV. All controls were negative HPV. In conclusion, DBD-FISH permitted the clear visualization of level high of DNA damage in the buccal epithelial cells of patients with OSSC respect to control group. Chromosome instability in oral mucosa may be an individual marker of malignant transformation in OSCC.

Low colonization prevalence of Staphylococcus aureus with reduced vancomycin susceptibility among patients undergoing hemodialysis in the San Francisco Bay area.

BACKGROUND: Staphylococcus aureus exhibits varying degrees of reduced vancomycin susceptibility, and strains with intermediate levels of resistance are thought to emerge by antibiotic selection of subpopulations in heterogeneously resistant precursor strains exposed to this antibiotic. We sought to determine the prevalence of and risk factors for carriage of potential heterogeneous vancomycin-intermediate S. aureus (hVISA). METHODS: We prospectively observed a cohort of 211 patients undergoing hemodialysis and performed quarterly surveillance cultures for up to 2 years. We screened for reduced vancomycin susceptibility using brain-heart infusion agar with 4 microg/mL vancomycin. RESULTS: We identified 10 colonizing potential hVISA isolates recovered from 7 patients among both methicillin-susceptible and methicillin-resistant S. aureus strains. No confirmed hVISA isolates were identified; we can be 95% certain that the prevalence of confirmed hVISA carriage does not exceed 1.4%. When compared with noncolonized hemodialysis patients, neither vancomycin exposure, duration of hospitalization, nor any baseline clinical or demographic factor was found to predict colonization with potential hVISA on univariate analyses; increased number of months receiving hemodialysis was associated with potential hVISA colonization on multivariate analysis. CONCLUSIONS: Despite numerous published reports of S. aureus with reduced vancomycin susceptibility, carriage of these isolates remains a rare phenomenon. Given the unclear clinical significance of potential hVISA, it is not clear whether clinical laboratories should identify such strains, or how they should do so.

An outbreak of group A Streptococcal infection among health care workers.

We describe the nosocomial transmission of group A Streptococcus species (GAS) from a single source patient to 24 health care workers (HCWs). DNA typing revealed that all of the isolates were identical to that of the source patient. The isolates were M type 1, positive for production of nicotine adenine dinucleotidase, and negative for opacity factor, all of which are factors reported to have a higher correlation with invasive disease. The 24 HCWs developed symptoms of pharyngitis < or =4 days after exposure to the source patient. Nosocomial transmission occurred < or =25 h after exposure to the source patient, before the institution of outbreak-control measures. A questionnaire was distributed to HCWs to help identify the factors responsible for the high attack rate among those who were exposed. Invasive GAS disease in a nosocomial setting can be highly transmissible. Rapid identification, early treatment, and adherence to infection-control practices may prevent or control outbreaks of infection.

Methicillin-resistant staphylococci and their treatment in the intensive care unit.

Methicillin resistance in Staphylococcus aureus (MRSA) and the coagulase-negative staphylococci (MRCNS) is widespread and continues to increase in prevalence, particularly in the health care setting. The clinical significance of methicillin resistance for patients with staphylococcal infections is not clear: studies in patients with bacteremia, pneumonia, and mediastinitis show a higher mortality with MRSA infection compared to methicillin-sensitive Staphylococcus aureus (MSSA) infection, though this may be due to underlying patient, pharmacodynamic, or microbiological differences. For serious methicillin-resistant staphylococcal infections, vancomycin-based regimens are preferred. Treatment alternatives for patients with severe methicillin-resistant infections who are unable to tolerate vancomycin include linezolid and quinupristin/dalfopristin; these agents should be considered second-line options, given the relative lack of clinical experience and the nonsignificant but consistent trends toward worse outcomes in bacteremia and pneumonia with these agents compared to vancomycin. For less severe infections, treatment options also include trimethoprim-sulfamethoxazole, or fluoroquinolones in combination with rifampin.

Community-acquired Methicillin-resistant Staphylococcus aureus: Epidemiology and Potential Virulence Factors.

Methicillin-resistant Staphylococcus aureus (MRSA) has been isolated from patients in the community. Some of these strains may have origins in the hospital, but others appear to be novel and unrelated to known hospital strains. Community MRSA strains have several distinguishing characteristics that may enable them to more readily colonize and infect otherwise healthy individuals. This article reviews recent publications addressing the epidemiology of MRSA in the community, risk factors associated with carriage, potentially associated virulence factors, and concepts of strain fitness as they pertain to MRSA. MRSA likely will be an increasingly important pathogen in the community.