The purpose of this in vitro study was to evaluate the effects of three 10% carbamide peroxide bleaching agents on adherence of bacteria to tooth enamel surface. Enamel specimens were subjected to one of three carbamide peroxide solutions for 8 h per day for 30 days. Control specimens were kept in saline solution. Profilometer evaluation of surface roughness was performed on all specimens. The adherence of Streptococcus tnutans was determined bacterio logically. There was no significant difference in surface roughness between the untreated and treated enamel specimens but a statistically significant difference was found in the adherence of S. mutatis to bleached and unbleached enamel specimens. Specimens treated with Opalescence® showed the highest adherence.
The purpose of this in vitro study was to evaluate the effects of three 10% carbamide peroxide bleaching agents on adherence of bacteria to tooth enamel surface. Enamel specimens were subjected to one of three carbamide peroxide solutions for 8 h per day for 30 days. Control specimens were kept in saline solution. Profilometer evaluation of surface roughness was performed on all specimens. The adherence of Streptococcus mutans was determined bacteriologically. There was no significant difference in surface roughness between the untreated and treated enamel specimens but a statistically significant difference was found in the adherence of S. mutans to bleached and unbleached enamel specimens. Specimens treated with Opalescence showed the highest adherence.
Resistance of gram-negative aerobic bacteria to aminoglycoside antibiotics differs by region and country. It is known that 54% of gram-negative bacilli in Turkey are resistant to gentamicin, 32% to netilmicin, 35% to tobramycin, and only 0.9% to amikacin. Resistance to these antibiotics is generally caused by aminoglycoside-modifying enzymes. The resistance mechanisms of 300 aminoglycoside-resistant gram-negative bacteria were evaluated by determination of susceptibility to selected aminoglycosides. Comparison of strains isolated from community acquired infections and hospital acquired infections was made. Of the strains from community, 45.4% had an aminoglycoside resistance pattern indicative of 2''-adenyltransferase [ANT(2'')]. This was found in 44.4% of the hospital isolates. In both groups the second common enzyme was the 3-acetyltransferase [AAC(3)-II], in 20.8% and 23.3% respectively. Overall, most strains had an aminoglycoside resistance pattern indicative of ANT(2''), followed by AAC(3)-II and AAC(3)-I. Among bacteria tested, AAC(3)-II was the most common enzyme in Pseudomonas aeruginosa. The results of this study suggest that local antibiotic prescribing patterns play an important role in regional resistance mechanisms.
From 2002 to 2003, a total of 381 consecutive S. pyogenes isolates were obtained from throat swabs (n = 337) and samples of pus (n = 31), sputum (n=10) and blood (n = 3) at Hacettepe University Hospital. The susceptibility of the isolates to erythromycin was tested by the agar dilution method. Erythromycin resistant strains were then tested for their MICs to azithromycin, clindamycin, and penicillin, their phenotype of resistance to macrolides-lincosamides-streptogramin B (MLSB) and for the presence of macrolide resistance genes. The rate of resistance to erythromycin was 6.8%. Constitutive (cMLSB), inducible (iMLSB), and M phenotypes of resistance were detected in 7.7, 30.8, and 57.7% of resistant strains, respectively. One strain had both cMLSB and iMLSB phenotypes. All M phenotypes carried the mefA gene, all iMLSB phenotype carried the ermTR gene, 1 isolate with cMLSB phenotype harboured the ermB gene, and 1 isolate with cMLSB phenotype carried both the ermB and mefA genes. One strain which showed cMLSB and iMLSB phenotypes harboured the ermB gene.
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