Leptospirosis in the Asia Pacific region

<p>Abstract</p> <p>Background</p> <p>Leptospirosis is a worldwide zoonotic infection that has been recognized for decades, but the problem of the disease has not been fully addressed, particularly in resource-poor, developing countries, where the major burden of the disease occurs. This paper presents an overview of the current situation of leptospirosis in the region. It describes the current trends in the epidemiology of leptospirosis, the existing surveillance systems, and presents the existing prevention and control programs in the Asia Pacific region.</p> <p>Methods</p> <p>Data on leptospirosis in each member country were sought from official national organizations, international public health organizations, online articles and the scientific literature. Papers were reviewed and relevant data were extracted.</p> <p>Results</p> <p>Leptospirosis is highly prevalent in the Asia Pacific region. Infections in developed countries arise mainly from occupational exposure, travel to endemic areas, recreational activities, or importation of domestic and wild animals, whereas outbreaks in developing countries are most frequently related to normal daily activities, over-crowding, poor sanitation and climatic conditions.</p> <p>Conclusion</p> <p>In the Asia Pacific region, predominantly in developing countries, leptospirosis is largely a water-borne disease. Unless interventions to minimize exposure are aggressively implemented, the current global climate change will further aggravate the extent of the disease problem. Although trends indicate successful control of leptospirosis in some areas, there is no clear evidence that the disease has decreased in the last decade. The efficiency of surveillance systems and data collection varies significantly among the countries and areas within the region, leading to incomplete information in some instances. Thus, an accurate reflection of the true burden of the disease remains unknown.</p

Carbon utilization phenome of Leptospira interrogans serovar Manilae strain K64

Background: Leptospirosis, an acute febrile disease caused by the pathogenic species of genus Leptospira, is one of the neglected emerging zoonoses that is of global public health concern. The recent genus-wide sequencing of Leptospira isolates led to the need for better understanding of the complex metabolic mechanisms of this organism. However, majority of the published studies on Leptospira metabolism were still the pioneering works of Baseman and Cox in the 60’s and their contemporaries. Knowledge on the carbon sources that supports the growth of a Leptospira species will not only contribute to the limited metabolic studies but will further support the reported genes and metabolic pathways of this organism. Objective:  Thus, this study aimed to describe the carbon utilization phenome of Leptospira interrogans serovar Manilae strain K64, one of the dominantly circulating pathogenic Leptospira in the Philippines. Methods:  A previously optimized BiologTM Gen III sole carbon utilization phenotype microarray assay protocol for leptospires was adapted. Results:  L. interrogans serovar Manilae strain K64 showed utilization of 29 carbon sources belonging to sugars and sugar derivatives, amino acids, methyl ester, carboxylic acid and fatty acids. These were N-acetyl-β-D-mannosamine, N-acetyl-D-galactosamine, N-acetyl neuraminic acid, D-fructose, D-galactose, 3-methyl glucose, D-fucose, L-fucose, L-rhamnose, inosine, D-fructose-6-phosphate, D-gluconic, D-glucuronic acid, glucuronamide, D-saccharic acid, D-aspartic acid, D-serine,  L-alanine, L-arginine,  L-histidine, L-pyroglutamic acid, L-serine, D-lactic acid methyl ester, citric acid, D-malic acid, L-malic acid, alpha ketoglutaric acid, alpha ketobutyric acid, and acetoacetic acid.  Discussion and Conclusion:  The carbon sources utilized by L. interrogans serovar Manilae strain K64 agreed well with the identified genes and metabolic pathways among Leptospira species.  Moreover, these 29 carbon sources have been previously reported to be associated in the biosynthesis of peptidoglycan, lipopolysaccharide, histidine, sulfur, amino acids, and isoleucine and in other metabolic pathways such as glycolysis, pentose-phosphate, pyruvate and fatty acid in Leptospira spp

Viability kinetics of Lactobacillus casei Shirota strain in a commercial fermented milk drink during refrigerated storage

© 2017 Derick Erl P Sumalapao, et al. Background: One of the most important parameters in a commercial fermented milk drink containing probiotics is the viability of the microorganisms. Aims and Objectives: This study described the viability kinetics of Lactobacillus casei Shirota strain in a commercial fermented milk drink during refrigerated storage using nonlinear models. Materials and Methods: Viability of L. casei Shirota strain was monitored during refrigerated storage using standard bacterial plate count method. Several nonlinear mathematical models such as the zero-order, first-order, and second-order kinetic equations were employed in describing the population dynamics. Best-fit models were selected based on prescribed criteria including sum of squares of the error, p-value, and coefficient of determination. Results: The viable counts of L. casei Shirota strain in the fermented milk samples stored under refrigerated conditions decreased from 3.73 × 108 colony forming units per ml (CFU/ml) to 2.70 × 108 CFU/ml when monitored every 3-4 days interval over 10 different monitoring points within the product’s indicated shelf life. The counts significantly differed between the monitoring points that were at least 14 days apart. The lowest viable count was still within the recommended therapeutic dose. The decrease in the bacterial population behaved under a second-order kinetic relationship. Conclusion: The viability of L. casei Shirota strain in a commercial fermented milk product during refrigerated storage is governed in accordance with the second-order kinetic mechanism

Topological Polar Surface Area, Molecular Weight, and Rotatable Bond Count Account for the Variations in the Inhibitory Potency of Antimycotics against Microsporum canis

Multivariate statistical models were utilized to identify the interaction between the inhibitory activity and the molecular properties of the different antimycotics against Microsporum canis. Information on the inhibitory potency against M. canis and molecular properties of antifungal agents were obtained from literature. The relationship between the inhibitory potency and the molecular properties of the different antimycotics against M. canis was established using multiple linear regression analysis (MLRA) and principal component analysis (PCA). Three major descriptors: topological polar surface area, molecular weight, and rotatable bond count of the antimycotics were identified to confer inhibitory action against M. canis using MLRA (r2 =0.8968, p<0.0001) and PCA (95.86% total contribution rate). Both MLRA and PCA as statistical approaches demonstrate their potential as tools in computational structure design and for possible synthesis of next generation antimycotics as more effective treatments of fungal infections

The Shifting Epidemiology of Hepatitis A in the World Health Organization Western Pacific Region

Within the past few decades, improvement in sanitation and economic growth has driven a changing epidemiology of hepatitis A in the Western Pacific Region (WPR) of the World Health Organization (WHO). In this review, we gathered available published information on hepatitis A epidemiology of the countries in the WPR and reviewed the trends reported in the literature from the years 2000 to 2021. Many countries have shifted from high endemicity to low endemicity. Moreover, the administration of the hepatitis A vaccine among children in recent years has shifted disease susceptibility to the older population. Seroprevalence among children has decreased in most countries, while nearly 100% seropositivity is seen in mid adulthood. This is contrary to the epidemiology seen in previous decades when most children achieved immunity by age ten. This also presents a paradox in that better living conditions have caused more vulnerability to the older age groups who are at higher risk for severe disease. Given these trends, we recommend vaccination of vulnerable populations such as the older age groups and inclusion of the hepatitis A vaccine in government immunization programs

In Vitro Sensitivity and Resistance of 46 Leptospira Strains Isolated from Rats in the Philippines to 14 Antimicrobial Agents▿ †

The in vitro susceptibilities of 46 Leptospira isolates from rats to 14 antimicrobial agents were tested. All of the strains were found to be sensitive to ampicillin, cefotaxime, ciprofloxacin, norfloxacin, doxycycline, erythromycin, and streptomycin. In contrast, the tested isolates showed resistance to amphotericin B, 5-fluorouracil, fosfomycin, trimethoprim, sulfamethoxazole, neomycin, and vancomycin. These findings will help in selecting effective and ineffective antimicrobials for treatment of leptospirosis and for the development of new selective media, respectively

In vitro resistance pattern of selected antifungal azoles against Candida albicans biofilms on silicone nasogastric tube

Prolonged use of implanted medical devices has been linked with device-associated infections. Since enteral tube feeding is increasing worldwide, the present study described the morphology of Candida albicans biofilms on the surface of silicone nasogastric tube (NGT) using fluorescence microscopy. With the emergence of multidrug-resistant fungal infections, the present study assessed the susceptibility profile of the biofilms to antifungal azoles namely fluconazole, miconazole, voriconazole, and posaconazole using the standard disc diffusion method. Microscopic studies of C. albicans biofilms revealed a complex heterogeneous structure with yeast cells and hyphal elements entrenched within a polysaccharide matrix. Planktonic C. albicans cells remained susceptible with posaconazole, fluconazole, miconazole, and voriconazole. However, the fungal biofilms exhibited resistance with miconazole. There was a significant reduction in the zone of inhibition on the 24-h, 48-h, and 72-h biofilm formation with posaconazole, voriconazole, and fluconazole, respectively. Kinetic investigation on C. albicans biofilm with posaconazole revealed a zero-order kinetic profile (R2=0.9774) whereas with voriconazole exhibited a first-order kinetic profile (R2=0.9974). These findings can possibly provide information regarding the resistance of fungal biofilms with antifungal azoles. Demonstration of common biofilm features will extend the findings of this study beyond fungi to polymicrobial infections, as new information and insights will influence several disciplines ranging from environmental microbiology to pharmaceutical drug design intended for biofilm-associated infections. © The Author(s) 2019

Frequency of typhoon occurrence accounts for the Poisson distribution of human leptospirosis cases across the different geographic regions in the Philippines

© 2019 by the Asian Pacific Journal of Tropical Medicine. All rights reserved. Objective: To study the distribution of human leptospirosis cases across the different geographic regions in the Philippines in 2015-2017 and to determine the relationship between the frequency of typhoon occurrence and human leptospirosis cases. Methods: Information on the frequency of leptospirosis cases and typhoon occurrence across the different regions in the Philippines from 2015 to 2017 was retrieved from the databases of the Department of Health and the Philippine Atmospheric, Geophysical, and Astronomical Services Administration, respectively. Descriptive measures on the prevalent cases and occurrence of typhoons across the different regions were summarized. Linear regression analysis was employed to establish the functional relationship between leptospirosis cases and typhoon occurrence. The distribution of human leptospirosis cases was assessed using the Poisson distribution. Results: The frequency of typhoon occurrence accounted for the significant linear variation in the geographic distribution of human leptospirosis cases in the Philippines (P\u3c0.001). Moreover, the human leptospirosis cases obeyed a Poisson distribution (λ=6.89, P\u3c0.001). Conclusions: The Philippines has frequently experienced severe weather perturbations such as typhoons resulting in flooding and subsequently increasing the risk of transmitting bacterial infections including leptospirosis. Information obtained regarding the determinants and distribution of human leptospirosis will provide better understanding of the disease propagation for subsequent design of optimal disease prevention measures, appropriate resource allocation, effective control strategies, and necessary public health programs