ABSTRACT
OBJECTIVES: The aim of this study was to evaluate the effectiveness of different concentrations of Chlorhexidine (CHX) and sodium hypochlorite (NaOCl) in disinfecting contaminated Resilon cones within one minute. STUDY DESIGN: Fifty Resilon cones were divided into seven experimental groups and three control groups of 5 cones each. The cones of experimental groups were contaminated with E. faecalis and subsequently disinfected with different concentrations of NaOCl or CHX. The cones were then transferred into glass tubes containing thioglycollate media and incubated for 7 days. The tubes were examined for turbidity every 24 hours, and if bacterial growth occurred, samples were plated, incubated, gram stained and observed under microscope to confirm E. faecalis growth. Negative, positive, and washing control groups were also used. RESULTS: All the positive and washing control showed profound E.faecalis growth. All the cones disinfected with CHX showed bacterial growth; however, no E. faecalis growth occurred in any samples disinfected with NaOCl. CONCLUSION: Sodium hypochlorite, at concentrations of 0.5 to 5.25%, is an effective agent for disinfection of contaminated Resilon cones within one minute; however, chlorhexidine is unable to disinfect Resilon cones during one-minute exposure.
Subject(s)
Chlorhexidine/administration & dosage , Disinfection/methods , Drug Contamination , Enterococcus faecalis , Root Canal Filling Materials , Sodium Hypochlorite/administration & dosageSubject(s)
Hospitals, Teaching , Pseudomonas aeruginosa/drug effects , beta-Lactamases/metabolism , Adult , Aged , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Drug Resistance, Microbial/genetics , Drug Resistance, Microbial/physiology , Female , Humans , Imipenem/pharmacology , Iran , Male , Microbial Sensitivity Tests , Middle Aged , Pseudomonas Infections/classification , Pseudomonas Infections/drug therapy , Pseudomonas Infections/epidemiology , Pseudomonas aeruginosa/classification , Pseudomonas aeruginosa/isolation & purification , Pseudomonas aeruginosa/metabolism , Serotyping , Young Adult , beta-Lactamases/blood , beta-Lactamases/drug effectsABSTRACT
Meticillin-resistant Staphylococcus aureus (MRSA) is an important cause of hospital-acquired infection. Methods for typing and epidemiological investigation of MRSA isolates have an important impact in detection of MRSA strains, source, transmission and control of these micro-organisms. The aims of this study were to study molecular diversity of MRSA isolates by randomly amplified polymorphic DNA (RAPD)-polymerase chain reaction (PCR), the surveillance efficacy of this method and determination of antibiotic resistance patterns of MRSA isolates. MRSA isolates were collected from clinical specimens and noses of 460 staff and inpatients admitted to Imam Khomeini and Paediatric Hospitals during a six-month period (2004-2005). Eighty MRSA strains, in which the presence of mecA gene had been confirmed by PCR, were subjected to RAPD-PCR using five primers and the results were summarised in a dendrogram to show the relationships between the test isolates. Antibiotic resistance patterns of MRSA isolates were also determined by disc agar diffusion method using 13 antibiotic discs according to Clinical and Laboratory Standards Institute guidelines. Forty-three RAPD-PCR profiles were detected. The test isolates were clustered into 18 taxa with 50% similarity, indicating the heterogeneity of our test isolates. MRSA isolates fell into 41 antibiotic resistance patterns. There was correlation between antibiotic resistance patterns and results of RAPD-PCR. Most of the MRSA isolates were multi-resistant.