BACKGROUND:There is a great negative impact of biofilm-mediated infection on patient health which necessitates the use of reliable methods for detecting biofilm producers.AIMS:This study was done to determine biofilm-producing ability and the presence of intercellular adhesion gene A in clinical staphylococcal isolates and to assess the reliability of two phenotypic methods used for biofilm detection.MATERIALS AND METHODS:Fifty staphylococcal strains were isolated from 100 conjunctival swabs from patients attended the Ophthalmology Outpatient Department of the Research Institute of Ophthalmology. Two phenotypic methods were used for detection of biofilm production; qualitative congo red agar (CRA); and quantitative microtiter plate. Polymerase chain reaction was used to determine the presence of icaA gene.RESULTS:In Staph aureus, 60% were positive biofilm forming and 40% were negative biofilm forming by both phenotypic methods. All positive biofilm-forming isolates were positive for icaA gene production. In coagulase negative staph, 50% were positive biofilm forming and 50% were negative biofilm forming by both phenotypic methods. All positive biofilm-forming strains were positive for icaA gene. All negative cases by CRA and microtiter plate methods were negative for icaA gene except two isolates. All staphylococcal isolates were subjected to antibiotic susceptibility test to correlate biofilm formation with multidrug resistance in staph.CONCLUSION:There is high significant correlation between icaA gene presence and biofilm forming ability; however, the biofilm-forming ability of some isolates in the absence of icaA gene highlights the importance of further genetic investigations of ica-independent biofilm formation mechanisms.

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Aim:The purpose of this study is to evaluate the anti-biofilm capacity of Diode laser 980 nm, triple antibiotic mixture and calcium hydroxide.Methods: Eighty five single-rooted teeth with mature apices were prepared using Protaper Universal rotary nickel titanium system till size # F4 then contaminated with E.faecalis. Irrigation done using 2.5% sodium hypochlorite followed by 17% EDTA. Samples were divided into 4 groups (n= 20) according to the irrigant activation method. Laser group,TAP group, Ca(OH) 2 group and the control group. Residual bacteria were plated onto Brain Heart Infusion media and determined as colony-forming units (CFU mL-1). Data were analyzed using one way ANOVA followed by performance of Tukey post hoc tests. Significance was set at p < 0.05. Results:There was a statistically significant reduction in the mean numbers of colony-forming units among all groups. However, none of the activation methods was able to kill E. faecalis biofilm completely. The Laser group behaved most effectively among all groups. Conclusion:The adjunctive use of 980nm laser is an effective method for bacterial reduction after chemo-mechanical instrumentation of the root canal.

Aim:The purpose of this study is to evaluate the antibacterial effect of Diode laser 980 nm, EndoVac and passive ultrasonic irrigation ex vivo. Methods:One hundred and five maxillary central incisors were standardized to 15mm in length. All samples were prepared using Protaper Universal rotary nickel titanium system till size # F4 then contaminated with E. faecalis. The irrigation protocol used was 2.5% sodium hypochlorite followed by 17% EDTA. Samples were randomly divided into 5 groups (n= 20) according to the irrigant activation method. LAI group, Diode laser 980nm. API group, EndoVac system. PUI group, passive ultrasonic activation. The positive control group, in which the irrigating solution was not activated and the negative control group in which the samples were not subjected to irrigation or activation. Residual bacteria were collected with sterile paper point, plated onto BHI media and incubated (37 °C, 48 h) to determine the colony-forming units (CFU mL-1). Data were analyzed using one-way ANOVA followed by performance of Tukey post hoc tests. Significance was set at p < 0.05. Scanning electron microscopy was used to investigate the changes in biofilm. Results:There was a statistically significant reduction in the mean numbers of colony-forming units among all groups. However, none of the activation methods was able to kill E. faecalis biofilm completely. The LAI group behaved most effectively among all groups. Conclusion:The adjunctive use of 980nm laser is an effective method for bacterial reduction after chemo-mechanical instrumentation of the root canal.