Viability Kinetic Profile, Morphological Structure, and Physicochemical Characterization of Candida albicans Biofilm on Latex Silicone Surfaces

Biofilm formed by Candida albicans on latex silicone surfaces was characterized by instrumental techniques such as fluorescence microscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy. The growth and viability of C. albicans on the biofilm formed were described using different kinetic rate equations. C. albicans biofilm has a complex and heterogenous structure with hyphal elements and yeast cells entrenched within a polysaccharide matrix. Spectroscopic studies revealed specific stretching frequencies of O-H, C-O, and C=O which can be attributed to the presence of some functionalities in the biofilm formed by C. albicans. Viability of C. albicans behaved in accordance with the first-order kinetic equation on the first 48 h, then shifted to a second-order kinetic equation until the 72 h, and had a doubling time of 70 h. Information on model biofilms with emphasis on growth rates and morphogenesis, structural organization, and physicochemical characteristics can possibly explain resistance to some antifungal treatments and subsequent synthesis of newer generation drugs for fungal biofilm-related infections.

Dipole Moment, Solvation Energy, and Ovality Account for the Variations in the Biological Activity of HIV-1 Reverse Transcriptase Inhibitor Fragments

Objective: A computational approach was employed to determine the interaction of molecular descriptors and the biological activity of the different fragments of HIV-1 reverse transcriptase inhibitors (RTIs). Methods: Using multiple linear regression analysis and leave-one-out validation method, a quantitative structure activity relationship (QSAR) model was developed to relate the biological activity (log IC50) of the different fragment-sized compounds against HIV-1 RT(WT) DNA-dependent DNA polymerase and molecular descriptors of these compounds. Results: QSAR model identified dipole moment, solvation energy, and ovality of fragment-sized compounds to confer reverse transcriptase inhibitory action. A highly significant correlation with log P, molecular weight, polarizability, molecular energy, zero-point energy, constant volume heat capacity at 298 K, and entropy was identified to account for the variations in the potency of RTIs. An increase in ovality, log P, and molecular weight of the fragment-sized compound renders a more active reverse transcriptase inhibition. Conclusion: The quality of the established QSAR model has been validated and demonstrates its potential as a tool for computational design and synthesis of next generation RTIs.

Knowledge, attitudes and practices of the community residents concerning the prevention and control of leptospirosis in the National Capital Region (NCR), Philippines

OBJECTIVE: This study assessed the knowledge, attitudes and practices of the community residents on the prevention and control of Leptospirosis in the National Capital Region, Philippines.METHODS: In this cross-sectional study, four-stage random cluster sampling proportional to size was used to select the 413 respondents from 30 villages in the National Capital Region. The mother or any responsible adult served as the respondent for the community survey which yielded data on the knowledge, attitudes, domestic practices, and sources of information for the prevention and control of Leptospirosis. Encoding was done using Epi Info Version 6. Descriptive statistics was generated through Microsoft Excel.RESULTS: Majority of the respondents were able to correctly identify that the causative agent of leptospirosis is bacteria (91%), that the disease is transmitted by the urine of infected of rats (89%) through skin abrasions (71%) and mucous membranes (57%). Most commonly identified signs and symptoms of the disease include acute febrile illness with myalgia (87%), difficulty of breathing and decreased urine output (72%). Majority identified the prevention and control measures correctly. Wearing of boots, maintaining a clean and orderly house and maintaining good sanitation were the top answers of the respondents. In terms of attitudes, respondents had positive attitudes towards the preventive practices of wearing boots or following health advisories of authorities (99%). Majority also believed that leptospirosis is curable if detected early (99%) and that it is a serious disease (98%). Similarly, more than 90% had positive attitude when it comes to health care. Wading in flood waters (93%), walking barefoot (85%) and conducting clearing activities after flood (63%) were the commonly believed forms of exposure to the disease. In terms of domestic practices, respondents usually clean their surroundings (40%), avoid wading in floodwaters (25%), wear boots (21%) to protect themselves from acquiring leptospirosis. Primary sources of information on leptospirosis were the mass media (46%), health workers (17%) and the health facilities (14%). The most common educational materials read by the respondents were flyers (9%), posters (8%), and leaflets (7%).CONCLUSION: In general, majority of the respondents were knowledgeable on the causes, signs and symptoms, and modes of transmission of leptospirosis, and had favorable attitudes towards the prevention and control measures against leptospirosis. However, when it comes to domestic practices, less than 40% actually implement measures for the prevention and control of leptospirosis. Respondents' main source of information was the mass media and very few have read educational materials containing information about the prevention and control of leptospirosis. 

Serologic characterization of Leptospira among rats trapped in selected public markets in Iloilo City, Philippines

OBJECTIVES: Rats have been identified as primary sources of leptospires in the environment. This study aimed to characterize Leptospira species circulating among rats found in public markets in Iloilo City, Philippines.           METHODS: Dark-field microscopy was used to determine leptospire presence in tissue cultures. Isolates from the cultures were characterized via serotyping with monoclonal and polyclonal antibodies. To characterize the antibodies present in rat sera, the microscopic agglutination test (MAT) was used.                                                                            RESULTS: In this study, 19 rats were obtained from 7 markets in Iloilo City. Three(3) rats (15%.8) were found to harbor leptospires in the urinary bladder (2) and kidney (1). Serotyping of the isolates showed that they did not belong to previously reported common serovars in the Philippines such as Manilae, Losbanos, Javanica or Grippotyphosa. Using another panel of polyclonal antibodies, it was shown that the isolates belonged to serovar lcterohaemorrhagiae. The MAT results showed that 16 (84.2%) serum samples were positive for anti-Leptospira antibodies. The most common infecting serovars were Autumnails (47.4%), Pomona (42.1%) Copenhageni (36.8%), and Hebdomadis (31.6%) other infecting serovars identified were lcterohaemorrhagiae, Poi, Grippotyphosa, Patoc, and Pyrogenes.                                                                                                                                                      CONCLUSION: The results of the present study provide baseline data on the circulating leptospiral serovars in iloilo City. Results suggest the possible role of rats in disease transmission in the study areas.

Occurrence and antimicrobial resistance of pathogenic vibrios isolated from green mussel, Perna viridis L. 1758 in Bacoor Bay, Cavite, Philippines

OBJECTIVES: To determine the occurrence and antimicrobial resistance of pathogenic vibrios from green mussel, Perna viridis in bacoor bay cavite. METHODS: Vibrios were isolated using TCBS agar and confirmed using API Identification kit. The relationship between the density of vibrios and environment parameters such as months, harvest sites and other physico-chemical parameters of water was determined. The isolated vibrios were subjected to antibiotic resistance testing to determine the resistance patterns.RESULTS: Pathogenic vibrios were isolated in all of the 90 mussel samples. Of the 183 vibrio isolates, 75 strains were V. alginolyticus and 53 strains belonged to V. cholerae wherein 18 (34%) of these were V. cholerae serotype O1. Forty nine (49) strains belonged to V. parahaemolyticus and six were V. vulnificus. Using the regression analysis, salinity, water temperature and ph have significant correlation on the density of vibrios (p=0.0309), with regression model, total vibrios = -16990763 + 145858 Salinity + 186808 Temperature + 1037886 pH. In the antimicrobial resistance assay,ampicillin had the highest drug resistance (37.8%) followed by nalidixic acid (10.4%), tetracycline (10.4%) and co-trimoxazole (9.3%).CONCLUSION: Pathogenic vibrios were isolated in mussel of Bacoor, Cavite and can be predicted using salinity, temperature and pH of the water. Thirty six percent (36%) of Vibrio isolates were resistance to ampicillin.