Mycobacterium avium resists exposure to the acidic conditions of the stomach

Organisms of the Mycobacterium avium complex are common pathogens in immunosuppressed patients such as individuals with AIDS. There is evidence that in AIDS patients, the main route for M. avium infection is the gastrointestinal tract. The stomach is a formidable barrier to pathogens and the ability to resist exposure to pH lower than 3 has been shown to be a virulence determinant of enteric pathogens. Incubation of three clinical isolates of M. avium under acidic pH revealed resistance of M. avium grown both to the exponential and stationary phase at pH 2.2 for 2 h. Inhibition of protein synthesis had no effect on the acid tolerance. When the duration of the incubation at pH 2.2 was extended to 24 h, bacteria grown to the stationary phase had a significantly greater tolerance to acid than exponential phase bacteria. M. avium incubated with acid in the presence of water was significantly more resistant to pH 2.2 than M. avium in the presence of buffer. Pre-adaptation in water prior to exposure to acidic conditions was also associated with increased resistance to pH 2.2. Isoosmolarity of Hank's balanced salt solution appears to be responsible for the impaired resistance to acid between 2 and 24 h of incubation. These findings indicate that M. avium is naturally tolerant to pH<3 and that pre-adaptation under conditions similar to the conditions where M. avium is found in the environment results in increased acid resistanc

Mutation position and type of substitution in the β-subunit of the RNA polymerase influence in-vitro activity of rifamycins in rifampicin-resistant Mycobacterium tuberculosis

Quantitative susceptibility testing for rifampicin, rifabutin and rifapentine of 36 Mycobacterium tuberculosis isolates with known sequences for the gene encoding for the RNA polymerase β-subunit (rpoB)revealed that both mutation position and type of amino acid substitution influence the in-vitro activity of rifamycins in rifampicin-resistant strain

Identification of the growth factor-binding sequence in the extracellular matrix protein MAGP-1

Editorial Análisis de casos Reforma agraria y lucha por la tierra en América Latina La Reforma Agraria en América Latina: una revolución frustrada Plinio Arruda Sampaio A Nova Questão Agrária e a Reinvenção do Campesinato: o caso do MST Carlos Walter Porto-Gonçalves El movimiento campesino en el Paraguay: conflictos, planteamientos y desafíos Tomás Palau Viladesau Movimientos campesinos e indígenas en México: la lucha por la tierra Luciano Concheiro Bórquez y Sergio Grajales Ventura Las luchas campesinas en Colombia en los albores del siglo XXI: de la frustración a la esperanza Isaías Tobasura Acuña Documentos O que precisa ser feito para mudar a vida do povo! Comunicado del Frente Nacional Campesino Ezequiel Zamora de Venezuela Cronología del conflicto La geografía política del conflicto social en América Latina José Seoane y Clara Algranati Región Sur Los sindicatos uruguayos ante el primer gobierno de izquierda Luis Senatore y Jaime Yaffé • Argentina • Brasil • Chile • Paraguay • Uruguay Región Andina Quito en abril: los forajidos derrotan al coronel Mario Unda • Bolivia • Colombia • Ecuador • Perú • Venezuela Región Norte La Guatemala de la resistencia y de la esperanza: las jornadas de lucha contra el CAFTA Simona Violetta Yagenova • Costa Rica • El Salvador • Guatemala • Honduras • México • Nicaragua • Panamá • Puerto Rico • República Dominicana Debates Territorio y movimientos sociales O retorno do território Apresentação por Maria Adélia Aparecida de Souza Milton Santos Outros territórios, outros mapas Ana Clara Torres Ribeiro Movimentos socioterritoriais e movimentos socioespaciais Bernardo Mançano Fernandes Territorios en disputa: iniciativas productivas y acción política en Mosconi, Argentina Norma Giarracca y Juan Wahren Sarjam [Vocablo en lengua aymara que significa ándate] Jorge A. Sainz Cardon

Group B Streptococcus colonization in pregnancy: prevalence and prevention strategies of neonatal sepsis

Early onset neonatal sepsis due to Group B streptococci (GBS) is responsible for severe morbidity and mortality of newborns. While different preventive strategies to identify women at risk are being recommended, the optimal strategy depends on the incidence of GBS-sepsis and on the prevalence of anogenital GBS colonization. We therefore aimed to assess the Group B streptococci prevalence and its consequences on different prevention strategies. We analyzed 1316 pregnant women between March 2005 and September 2006 at our institution. The prevalence of GBS colonization was determined by selective cultures of anogenital smears. The presence of risk factors was analyzed. In addition, the direct costs of screening and intrapartum antibiotic prophylaxis were estimated for different preventive strategies. The prevalence of GBS colonization was 21%. Any maternal intrapartum risk factor was present in 37%. The direct costs of different prevention strategies have been estimated as follows: risk-based: 18,500 CHF/1000 live births, screening-based: 50,110 CHF/1000 live births, combined screening- and risk-based: 43,495/1000 live births. Strategies to prevent GBS-sepsis in newborn are necessary. With our colonization prevalence of 21%, and the intrapartum risk profile of women, the screening-based approach seems to be superior as compared to a risk-based approac

SARS-CoV-2 Nucleocapsid Protein Mutations Found in Switzerland Disrupt N-Gene Amplification in Commonly Used Multiplex RT-PCR Assay

At the end of 2021, we observed an increase in N-gene target failures (NGTF) with the TaqPathTM COVID-19 CE-IVD RT-PCR Kit from Thermo Fisher Scientific (TaqPath). We subsequently used whole-genome sequencing (Oxford Nanopore Technology) to identify potential issues with N-gene PCR efficacy. Among 168,101 positive samples with a cycle threshold (CT) value <30 from August 2021 to May 2022, 194 specimens without N-gene amplification by PCR were identified (0.12%). Most NGTF samples originated from a wave of infection attributable to the Delta variant (B.1.617.2) and its sublineages. Sequencing revealed the nucleotide substitution G28922T (A217S) in 151 samples (88.8%). The substitution G215C, a hallmark mutation for Delta lineages, was concurrently present in all of these samples. Ten samples (5.9%) carried the deletion 28,913-28,918 (del214/215), eight samples (4.7%) the deletion 28,913-28,915 (del214) and one sample (0.6%) the deletion 28,892-28,930 (del207-219). Samples showing intact N-gene amplification by PCR lacked these specific mutations, but delayed-type amplification (i.e., partial or pNGTF) was attributable to the exclusive presence of A217S. As the N gene is a common target in many RT-PCR methods for SARS-CoV-2, an in-depth analysis of single-target failures using a combination with viral whole genome sequencing may allow for the identification of diagnostic flaws and eventual new variants

New treatment of the chiral SU(3) quark mean field model

We perform a study of infinite hadronic matter, finite nuclei and hypernuclei with an improved method of calculating the effective baryon mass. A detailed study of the predictions of the model is made in comparison with the available data and the level of agreement is generally very good. Comparison with an earlier treatment shows relatively minor differences at or below normal nuclear matter density, while at high density the improved calculation is quite different. In particular, we find no phase transition corresponding to chiral symmetry restoration in high density nuclear matter.Comment: 19 pages, 11 figure