Protective role of stratum corneum in percutaneous Leptospira infection in a hamster model.

Leptospira enters humans and animals through injured skin or mucous membranes by direct or indirect contact with urine excreted from infected reservoirs. Individuals with cut or scratched skin are at high risk of infection and are recommended to be protected from contact with Leptospira, but the risk of infection via skin without apparent wounds is unknown. We hypothesized that the stratum corneum of the epidermis might prevent percutaneous invasion of leptospires.

Is an Environmental Bacterium That Grows in Waterlogged Soil.

Leptospirosis is a zoonotic disease caused by infection with pathogenic leptospires. Consistent with recent studies by other groups, leptospires were isolated from 89 out of 110 (80.9%) soil or water samples from varied locations in the Philippines in our surveillance study, indicating that leptospires might have a life cycle that does not involve animal hosts.

Novel Virulent Bacteriophage ΦSG005, Which Infects , Forms a Distinct Clade among Streptococcus Viruses.

Bacteriophages are viruses that specifically infect bacteria and are classified as either virulent phages or temperate phages. Despite virulent phages being promising antimicrobial agents due to their bactericidal effects, the implementation of phage therapy depends on the availability of virulent phages against target bacteria. Notably, virulent phages of , which resides in the oral cavity and is an opportunistic pathogen that can cause periodontitis and endocarditis have previously never been found.

Molecular and phenotypic characterization of Leptospira johnsonii sp. nov., Leptospira ellinghausenii sp. nov. and Leptospira ryugenii sp. nov. isolated from soil and water in Japan.

In a previous study, 50 of 132 soil samples collected throughout Japan were found to be Leptospira-positive. In the present study, three strains identified in the collected specimens, three, E8, E18 and YH101, were found to be divergent from previously described Leptospira species according to 16S ribosomal RNA gene sequence analysis. These three strains have a helical shape similar to that of typical Leptospira and were not re-isolated from experimental mice inoculated with the cultured strains.

Molecular analysis of Streptococcus pyogenes strains isolated from patients with recurrent pharyngitis after oral amoxicillin treatment.

Purpose: The most common illness caused by Streptococcus pyogenes (Group A streptococcus; GAS) is acute pharyngitis. It has been reported that a small percentage of patients experience recurrent GAS pharyngitis after 10 days of treatment with oral amoxicillin. The aim of this study was to clarify whether recurrent GAS pharyngitis is reactivation caused by the primary strain remaining at the infection site, or if the reinfection is caused by newly acquired strains.

Characterization of Leptospira species isolated from soil collected in Japan.

Leptospira were isolated from soil obtained from Hokkaido, the northernmost island, to Okinawa, the southernmost island, of Japan using sulfamethoxazole, trimethoprim, amphotericin B, fosfomycin, and 5- fluorouracil. Fifty of 132 soil samples (37.9%) were culture-positive.

Adipose tissue is the first colonization site of Leptospira interrogans in subcutaneously infected hamsters.

Leptospirosis is one of the most widespread zoonoses in the world, and its most severe form in humans, "Weil's disease," may lead to jaundice, hemorrhage, renal failure, pulmonary hemorrhage syndrome, and sometimes,fatal multiple organ failure. Although the mechanisms underlying jaundice in leptospirosis have been gradually unraveled, the pathophysiology and distribution of leptospires during the early stage of infection are not well understood. Therefore, we investigated the hamster leptospirosis model, which is the accepted animal model of human Weil's disease, by using an in vivo imaging system to observe the whole bodies of animals infected with Leptospira interrogans and to identify the colonization and growth sites of the leptospires during the early phase of infection.

Non-exponential growth of Mycobacterium leprae Thai-53 strain cultured in vitro.

In this study, attempts were made to culture this bacterium in media supplemented with a variety of biological materials to determine why cultivation of Mycobacterium leprae in vitro has not this far been successful. A slight increase in the number of cells in medium supplemented with human blood plasma and an extract of nude mouse tissue as observed after more than 3 months of cultivation at 30 °C. To ascertain whether this increase was real growth, the growth was analyzed by droplet digital PCR, which showed a slow increase in the copy number of cell-associated DNA and the release of a large amount of DNA into the culture medium from bacterial cells during cultivation.

A soluble form of Siglec-9 provides a resistance against Group B Streptococcus (GBS) infection in transgenic mice.

Group B Streptococcus (GBS) is a leading cause of invasive bacterial infections in human newborns. A key GBS virulence factor is its capsular polysaccharide (CPS), possessing terminal sialic acid residues that suppress host immune response and provide a survival advantage to the pathogen. CPS binds to Siglec-9 expressed on neutrophils, which is expected to down-regulate the immune responsiveness of neutrophils.

Legionella dumoffii Tex-KL Mutated in an Operon Homologous to traC-traD is Defective in Epithelial Cell Invasion.

Objective: To understand the mechanism of invasion by Legionella dumoffii.

Methods: The L. dumoffii strain Tex-KL was mutated using the Tn903 derivative, Tn903dIIlacZ.

Colony types and virulence traits of Legionella feeleii determined by exopolysaccharide materials.

Legionella feeleii is a Gram-negative pathogenic bacterium that causes Pontiac fever and pneumonia in humans. When L. feeleii serogroup 1 (ATCC 35072) was cultured on BCYE agar plates, two types of colonies were observed and exhibited differences in color, opacity and morphology.

Effects of white rice containing enriched gamma-aminobutyric acid on blood pressure.

Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter with beneficial effects including antihypertension and antistress properties. In this study, we examined the effects of GABA-enriched white rice (GABA rice) on blood pressure (BP) in 39 mildly hypertensive adults in a randomized, double-blind, placebo-controlled study. The participants were divided into a test group (n = 22) who consumed rice with 11.

Filament formation of Salmonella Paratyphi A accompanied by FtsZ assembly impairment and low level ppGpp.

Previously, we reported that Salmonella enterica serovar Paratyphi A strain S602 grew into multinuclear, nonseptate, and nonlethal filaments on agar plates containing nitrogenous salts. Strain S602 was more sensitive to osmotic and oxidative stress than the reference strain 3P243 of nonfilamentous Salmonella Paratyphi A. Strain S602 had an amber mutation (C154T) in rpoS.

Elevated guanosine 5'-diphosphate 3'-diphosphate level inhibits bacterial growth and interferes with FtsZ assembly.

FtsZ, a protein essential for prokaryotic cell division, forms a ring structure known as the Z-ring at the division site. FtsZ has a GTP binding site and is assembled into linear structures in a GTP-dependent manner in vitro. We assessed whether guanosine 5'-diphosphate 3'-diphosphate (ppGpp), a global regulator of gene expression in starved bacteria, affects cell division in Salmonella Paratyphi A.

Comparative analysis of virulence traits between a Legionella feeleii strain implicated in Pontiac fever and a strain that caused Legionnaires' disease.

Legionella strains of the same species and serogroup are known to cause Legionnaires' disease (a potentially fatal atypical pneumonia) or Pontiac fever (a mild, flu-like disease), but the bacterial factors that define these dramatic differences in pathology have not been elucidated. To gain a better understanding of these factors, we compared the characteristics of Legionella feeleii strains that were isolated from either a sample of freshwater implicated in an outbreak of Pontiac fever (ATCC 35072, serogroup 1, LfPF), or a patient with Legionnaires' disease (ATCC 38549, serogroup 2, LfLD). Growth of LfPF and LfLD in BYE broth was slower than the positive control, Legionella pneumophila strain JR32.

Hydrogen peroxide causes Vibrio vulnificus bacteriolysis accelerated by sulfonyl fluoride compounds.

Induction of bacteriolysis of Vibrio vulnificus cells by 10 mM hydrogen peroxide (H(2)O(2)) was analyzed. All Vibrio species examined, except for Vibrio hollisae, were lysed by 10 mM H(2)O(2). Bacteriophage induction was not the cause of H(2)O(2)-induced bacteriolysis.

The usefulness of semi-solid medium in the isolation of highly virulent Leptospira strains from wild rats in an urban area of Fukuoka, Japan.

Leptospirosis is a worldwide zoonosis. The importance of urban leptospirosis is recognized in Japan: urban rats carry pathogenic leptospires and people acquire these pathogens through contact with surface water or soil contaminated by the urine of the infected animals. To determine the current Leptospira carriage rate in urban rats, 29 wild rats were trapped in the central area of Fukuoka and strains isolated from their kidneys and urine analyzed.

Using discrete choice modeling to evaluate the preferences and willingness to pay for leptospirosis vaccine.

Leptospirosis is highly endemic in the Philippines and a serious concern to public health. Local research on candidate vaccine is moving through the development pipeline. The availability of vaccines alone does not guarantee acceptance because individuals' vaccination choice decision is influenced by several factors.

Characterization of Leptospira infection in suckling and weaning rat pups.

Rats are known to be the most important reservoirs of Leptospira spp. However, the leptospiral dose and age at which rats become resistant to Leptospira infection are not yet well elucidated. Aimed to characterize leptospirosis in rat pups, we found that suckling pups (4-, 7-, and 14-day old) are susceptible to leptospires and resistance starts from the weaning age (23-day old).

[Leptospirosis now-the centennial of the discovery of Weil's disease pathogen].

This year, 2014, marks the centennial of the discovery of Leptospira as the Weil's disease pathogen by Ryokichi Inada, Yutaka Ido and their colleagues. Leptospirosis is a worldwide zoonosis especially in countries with tropical and subtropical climates. Recently, the number of patients with leptospirosis dramatically decreased in Japan because public hygiene has greatly improved, the mechanization of agriculture was introduced, and farmers started using rubber boots and gloves while working in the field.

Molecular characterization of serologically atypical provisional serovars of Shigella isolates from Kolkata, India.

During 2000-2004, 13 Shigella strains that were untypable by commercially available antisera were isolated from children <5 years of age with acute diarrhoea in Kolkata. These strains were subsequently identified as Shigella dysenteriae provisional serovar 204/96 (n = 3), Shigella dysenteriae provisional serovar E23507 (n = 1), Shigella dysenteriae provisional serovar I9809-73 (n = 1), Shigella dysenteriae provisional serovar 93-119 (n = 1), Shigella flexneri provisional serovar 88-893 (n = 6) and Shigella boydii provisional serovar E16553 (n = 1). In this study, characterization of those provisional serovars of Shigella was performed with respect to their antimicrobial resistance, plasmids, virulence genes and PFGE profiles.

PCR and culture identification of pathogenic Leptospira spp. from coastal soil in Leyte, Philippines, after a storm surge during Super Typhoon Haiyan (Yolanda).

Leptospirosis is a zoonosis caused by pathogenic Leptospira spp. Most of the outbreaks of leptospirosis occur after floods caused by heavy rain in countries where Leptospira spp. are endemic.

Leptospira-rat-human relationship in Luzon, Philippines.

Leptospirosis is a zoonotic infection that is caused by the pathogenic species of Leptospira. Rats are the most important reservoirs of these organisms. Our study aimed to characterize Leptospira isolates from humans and rats and elucidate the Leptospira-rat-human relationship in Luzon, Philippines.

Destruction of the hepatocyte junction by intercellular invasion of Leptospira causes jaundice in a hamster model of Weil's disease.

Weil's disease, the most severe form of leptospirosis, is characterized by jaundice, haemorrhage and renal failure. The mechanisms of jaundice caused by pathogenic Leptospira remain unclear. We therefore aimed to elucidate the mechanisms by integrating histopathological changes with serum biochemical abnormalities during the development of jaundice in a hamster model of Weil's disease.

Identification of leptospiral 3-hydroxyacyl-CoA dehydrogenase released in the urine of infected hamsters.

Background: Leptospirosis is a global zoonosis caused by pathogenic Leptospira. The non-specific clinical signs and symptoms of leptospirosis lead to its misdiagnosis. To date, there is still no reliable rapid test kit that can accurately diagnose leptospirosis at bedside or in field.