New Variant of Multidrug-Resistant Serovar Typhimurium Associated with Invasive Disease in Immunocompromised Patients in Vietnam.

Nontyphoidal (NTS), particularly serovar Typhimurium, is among the leading etiologic agents of bacterial enterocolitis globally and a well-characterized cause of invasive disease (iNTS) in sub-Saharan Africa. In contrast,  Typhimurium is poorly defined in Southeast Asia, a known hot spot for zoonotic disease with a recently described burden of iNTS disease. Here, we aimed to add insight into the epidemiology and potential impact of zoonotic transfer and antimicrobial resistance (AMR) in  Typhimurium associated with iNTS and enterocolitis in Vietnam.

Molecular Surveillance Identifies Multiple Transmissions of Typhoid in West Africa.

Background: The burden of typhoid in sub-Saharan African (SSA) countries has been difficult to estimate, in part, due to suboptimal laboratory diagnostics. However, surveillance blood cultures at two sites in Nigeria have identified typhoid associated with Salmonella enterica serovar Typhi (S. Typhi) as an important cause of bacteremia in children.

Fluoroquinolone-Resistant Enteric Bacteria in Sub-Saharan Africa: Clones, Implications and Research Needs.

Fluoroquinolones came into widespread use in African countries in the early 2000s, after patents for the first generation of these drugs expired. By that time, quinolone antibacterial agents had been used intensively worldwide and resistant lineages of many bacterial species had evolved. We sought to understand which Gram negative enteric pandemic lineages have been reported from Africa, as well as the nature and transmission of any indigenous resistant clones.

A Phylogenetic and Phenotypic Analysis of Salmonella enterica Serovar Weltevreden, an Emerging Agent of Diarrheal Disease in Tropical Regions.

Salmonella enterica serovar Weltevreden (S. Weltevreden) is an emerging cause of diarrheal and invasive disease in humans residing in tropical regions. Despite the regional and international emergence of this Salmonella serovar, relatively little is known about its genetic diversity, genomics or virulence potential in model systems.

Non-typhoidal Salmonella Typhimurium ST313 isolates that cause bacteremia in humans stimulate less inflammasome activation than ST19 isolates associated with gastroenteritis.

Salmonella is an enteric pathogen that causes a range of diseases in humans. Non-typhoidal Salmonella (NTS) serovars such as Salmonella enterica serovar Typhimurium generally cause a self-limiting gastroenteritis whereas typhoidal serovars cause a systemic disease, typhoid fever. However, S.

Signatures of adaptation in human invasive Salmonella Typhimurium ST313 populations from sub-Saharan Africa.

Two lineages of Salmonella enterica serovar Typhimurium (S. Typhimurium) of multi-locus sequence type ST313 have been linked with the emergence of invasive Salmonella disease across sub-Saharan Africa. The expansion of these lineages has a temporal association with the HIV pandemic and antibiotic usage.

Ceftriaxone-resistant Salmonella enterica serotype typhimurium sequence type 313 from Kenyan patients is associated with the blaCTX-M-15 gene on a novel IncHI2 plasmid.

Multidrug-resistant bacteria pose a major challenge to the clinical management of infections in resource-poor settings. Although nontyphoidal Salmonella (NTS) bacteria cause predominantly enteric self-limiting illness in developed countries, NTS is responsible for a huge burden of life-threatening bloodstream infections in sub-Saharan Africa. Here, we characterized nine S.

Relationship between antibody susceptibility and lipopolysaccharide O-antigen characteristics of invasive and gastrointestinal nontyphoidal Salmonellae isolates from Kenya.

Background: Nontyphoidal Salmonellae (NTS) cause a large burden of invasive and gastrointestinal disease among young children in sub-Saharan Africa. No vaccine is currently available. Previous reports indicate the importance of the O-antigen of Salmonella lipopolysaccharide for virulence and resistance to antibody-mediated killing.

Malaria prevalence, anemia and baseline intervention coverage prior to mass net distributions in Abia and Plateau States, Nigeria.

Background: Nigeria suffers the world's largest malaria burden, with approximately 51 million cases and 207,000 deaths annually. As part of the country's aim to reduce by 50% malaria-related morbidity and mortality by 2013, it embarked on mass distribution of free long-lasting insecticidal nets (LLINs).

Methods: Prior to net distribution campaigns in Abia and Plateau States, Nigeria, a modified malaria indicator survey was conducted in September 2010 to determine baseline state-level estimates of Plasmodium prevalence, childhood anemia, indoor residual spraying (IRS) coverage and bednet ownership and utilization.

Intracontinental spread of human invasive Salmonella Typhimurium pathovariants in sub-Saharan Africa.

A highly invasive form of non-typhoidal Salmonella (iNTS) disease has recently been documented in many countries in sub-Saharan Africa. The most common Salmonella enterica serovar causing this disease is Typhimurium (Salmonella Typhimurium). We applied whole-genome sequence-based phylogenetic methods to define the population structure of sub-Saharan African invasive Salmonella Typhimurium isolates and compared these to global Salmonella Typhimurium populations.

High-resolution single nucleotide polymorphism analysis distinguishes recrudescence and reinfection in recurrent invasive nontyphoidal Salmonella typhimurium disease.

Background: Bloodstream infection with invasive nontyphoidal Salmonella (iNTS) is common and severe among human immunodeficiency virus (HIV)-infected adults throughout sub-Saharan Africa. The epidemiology of iNTS is poorly understood. Survivors frequently experience multiply recurrent iNTS disease, despite appropriate antimicrobial therapy, but recrudescence and reinfection have previously been difficult to distinguish.

Structure, diversity, and mobility of the Salmonella pathogenicity island 7 family of integrative and conjugative elements within Enterobacteriaceae.

Integrative and conjugative elements (ICEs) are self-mobile genetic elements found in the genomes of some bacteria. These elements may confer a fitness advantage upon their host bacteria through the cargo genes that they carry. Salmonella pathogenicity island 7 (SPI-7), found within some pathogenic strains of Salmonella enterica, possesses features indicative of an ICE and carries genes implicated in virulence.

Streptomyces atacamensis sp. nov., isolated from an extreme hyper-arid soil of the Atacama Desert, Chile.

The taxonomic position of a Streptomyces strain isolated from an extreme hyper-arid soil sample collected from the Atacama Desert was determined using a polyphasic approach. The strain, isolate C60(T), had chemical and morphological features typical of members of the genus Streptomyces and formed a distinct phyletic line in the Streptomyces 16S rRNA gene tree, together with the type strain of Streptomyces radiopugnans. The two strains were distinguished readily using a combination of phenotypic properties and by a DNA-DNA relatedness value of 23.

Streptomyces deserti sp. nov., isolated from hyper-arid Atacama Desert soil.

The taxonomic position of a Streptomyces strain isolated from a hyper-arid desert soil was established using a polyphasic approach. The organism had chemical and morphological properties typical of the genus Streptomyces and formed a phyletic line at the periphery of the Streptomyces coeruleorubidus subcluster in the 16S rRNA gene tree. DNA:DNA relatedness values between the isolate and its nearest phylogenetic neighbours, Streptomyces lomondensis NRRL 3252(T) and Streptomyces lusitanus NRRL B-12501(T) were 42.

Diverse metabolic profiles of a Streptomyces strain isolated from a hyper-arid environment.

The metabolic profile of Streptomyces sp. strain C34, isolated from the Chilean hyper-arid Atacama Desert soil, is dependent on the culture media used for its growth. The application of an OSMAC approach on this strain using a range of cultivation media resulted in the isolation and identification of three new compounds from the rare class of 22-membered macrolactone polyketides, named chaxalactins A-C (1-3).

Chaxamycins A-D, bioactive ansamycins from a hyper-arid desert Streptomyces sp.

Streptomyces sp. strain C34, isolated from soil collected in the Chilean hyper-arid Atacama Desert, was cultured on different media, resulting in the isolation and identification of four new ansamycin-type polyketides. The organism was selected for chemical investigation on the basis of a genome-mining PCR-based experiment targeting the gene encoding rifamycin-specific 3-amino-5-hydroxybenzoic acid synthetase (AHBA).

Effects of annual mass treatment with ivermectin for onchocerciasis on the prevalence of intestinal helminths.

We evaluated the effect of annual ivermectin (IV) distribution for onchocerciasis on the prevalence of soil transmitted helminth (STH) infections in school-aged (SAC) and preschool-aged (PAC) children by comparing children in villages that had received treatment for 13 years to those from socioeconomically similar villages in untreated areas. We enrolled 1,031 SAC and 211 PAC for Kato Katz examinations. Treated areas had a lower prevalence of Ascaris (SAC: 3% versus 12%, P < 0.

Lechevalieria atacamensis sp. nov., Lechevalieria deserti sp. nov. and Lechevalieria roselyniae sp. nov., isolated from hyperarid soils.

The taxonomic positions of three Lechevalieria-like strains isolated from hyperarid soils of the Atacama Desert, Chile, were established by using a polyphasic approach. The organisms had chemical and morphological properties consistent with their classification in the genus Lechevalieria. They formed a distinct subclade in the Lechevalieria 16S rRNA gene clade and were most closely related to the type strain of Lechevalieria xinjiangensis.

Diversity of culturable actinomycetes in hyper-arid soils of the Atacama Desert, Chile.

The Atacama Desert presents one of the most extreme environments on Earth and we report here the first extensive isolations of actinomycetes from soils at various locations within the Desert. The use of selective isolation procedures enabled actinomycetes to be recovered from arid, hyper-arid and even extreme hyper-arid environments in significant numbers and diversity. In some cases actinomycetes were the only culturable bacteria to be isolated under the conditions of this study.