ABSTRACT
Aims: Evaluation of leaves methanol extracts from Plectranthus barbatus and Plectranthus ecklonii (Lamiaceae) against oral pathogens. Place and Duration of the Study: P. barbatus and P. ecklonii, cultivated in Botanic Garden of the University of Lisbon, were collected during winter 2009. Methodology: Methanol extracts were prepared and the compounds separated and identified by HPLC-DAD and mass spectrometry. The anticariogenic activity was determined by measuring the inhibition activity towards the growth of the pathogens Streptococcus mutans and S. sobrinus together with the inhibitory activity against the enzyme glucosyltransferase (GTF) involved in the biosynthesis of glucans. Results: Phytochemical analysis of the extracts revealed the presence of two abietane diterpenoids in P. barbatus and two quinone methides together with rosmarinic acid in P. ecklonii. The two Plectranthus extracts showed bacteriostatic activity with minimum inhibitory concentrations (MIC) of 0.3 mg/mL. The minimum bactericidal concentrations (MBC) obtained for both extracts were 0.6 mg/mL against S. sobrinus and 0.8 mg/mL against S. mutans. After exposing both strains during 2h to P. ecklonii extract, 80% of inhibition against viable cells on a 24h old biofilm was observed. When methanol extracts of P. barbatus and P. ecklonii were used to inhibit the growth of the two bacterial strains in biofilm, IC50 (inhibitory concentration) values were 1.9 mg/mL and 0.57 mg/mL against S. sobrinus biofilm and 0.7 mg/mL and 0.8 mg/mL against S. mutans biofilm, respectively. P. barbatus IC50 values for the biofilm formation were 0.63 mg/mL and 0.13 mg/mL against S. sobrinus and S. mutans, respectively. P. ecklonii IC50 values for the biofilm formation were 0.07 mg/mL and 0.12 mg/mL against S. sobrinus and S. mutans biofilm. GTF from S. sobrinus was inhibited in 30% when 0.3 mg/mL of P. barbatus extract was used. Conclusions: These extracts are important in the control of biofilms and useful in the prevention of oral diseases.
ABSTRACT
PURPOSE: To investigate the shifting trends of pathogenic organisms, antibiotic resistance, and clinical characteristics of patients with Gram-positive bacterial keratitis and to elucidate the prognostic factors. METHODS: We performed a retrospective chart review of 152 isolates in 146 eyes with Gram-positive bacterial keratitis between January 1998 and December 2012. The study was divided into 5 periods for analysis of the bacteriological profiles and in vitro antibiotic resistance. The epidemiological and clinical characteristics were compared according to bacterial isolates. Logistic regression analysis was performed to determine the risk factors. RESULTS: Gram-positive bacterial keratitis tended to decrease and significant change in the distribution of isolates was not observed. Commonly isolated organisms were S. epidermidis (48.7%), S. aureus (25.0%), and S. pneumoniae (7.2%) in order of frequency. The resistance to fluoroquinolone tended to increase (p = 0.104) and resistance to gentamicin was significantly decreased (p = 0.01). S. epidermidis had the shortest corneal epithelium healing time (p = 0.035) and the most favorable visual outcome after treatment (p = 0.035) compared with the other species. Risk factors for poor visual outcomes included a best corrected visual acuity less than 0.1 at initial evaluation and an epithelial healing time greater than 10 days. CONCLUSIONS: Gram-positive bacterial keratitis tended to decrease and S. epidermidis was the most common isolate. The clinical prognosis was most favorable in S. epidermidis. The BCVA less than 0.1 at initial evaluation was an important risk factor for poor visual outcome and surgical treatment in Gram-positive bacterial keratitis.