Emergence and spread of a new community-genotype methicillin-resistant Staphylococcus aureus clone in Colombia

© 2017 The Author(s). Background: Community-genotype methicillin-resistant Staphylococcus aureus (CG-MRSA) clones are a global concern due to their resistance and increased virulence and their ability to cause infections both hospitalized patients and healthy people in the community. Here, we characterize 32 isolates of a new CG-MRSA clone. These isolates were identified in four cities in Colombia, South America. Methods: The isolates were recovered from four different epidemiological and prospective studies that were conducted in several regions of Colombia. Molecular characterizations included multilocus sequence typing; pulsed-field gel electrophoresis; SCCmec, agr and spa typing; and whole-genome sequencing. Results: All isolates belonged to ST923 (clonal complex 8), harbouring SCCmec IVa and a spa type t1635 and lacking an arginine catabolism mobile element. The isolates were classified as COL923, were resistant to at least one non-beta-lactam antibiotic, and exhibited high frequencies (>60%) of resistance to macrolides and tetracycline. Using whole-genome sequencing, we found that this new clone harbours novel prophage 3 and beta-island structures and a slightly different pathogenicity island 5. Moreover, isolates belonging to the COL923 clone are grouped in a different clade than USA300 and USA300-LV. Conclusion: Our results show the emergence and spread of the COL923 clone in different cities in Colombia. This clone is resistant to several antibiotics and possesses new structures in its mobile genetic elements

Izdvajanje bakterije Escherichia coli O157:H7 i njezin dokaz lančanom reakcijom polimerazom u crijevima filipinskih šišmiša.

It is currently reported that bats in the Philippines harbor bacterial organism (Salmonella spp.) with pathogenic potential. The paper describes the conventional isolation and polymerase chain reaction (PCR) assay for the detection of another bacterium, Escherichia coli, from a sample population of 56 apparently healthy bats collected from Laguna and Quezon City, Philippines. Nineteen of the samples were positive for E. coli using the conventional method of isolation, while PCR molecularly detected the bacteria in 15 samples. The presence of hemolysin among the isolates was not observed. The isolates were subjected to E. coli O157:H7 serotype detection using the latex agglutination test and another PCR assay specific for this serotype. The data revealed that none of the isolates was positive for E. coli O157:H7 using serological and molecular diagnostic methods, which indicates that bats from Laguna and Quezon City, Philippines were not carriers of the pathogenic strain, E. coli O157:H7. The study also presents the first local report of conventional isolation and molecular detection of E. coli from Philippine bats.Poznato je da šišmiši na Filipinima mogu biti nositelji potencijalno patogenih bakterija, npr. salmonela. U radu je opisano izdvajanje i dokaz lančanom reakcijom polimerazom bakterije Escherichia coli iz 56 naizgled zdravih šišmiša uhvaćenih na području Laguna i Quezon City na Filipinima. E. coli bila je izdvojena iz 19 uzoraka, dok je lančanom reakcijom polimerazom ona bila dokazana u 15 uzoraka. Izolati nisu tvorili hemolizu, a lateks aglutinacija i specifični PCR rabljeni su za dokaz serovara O157:H7 bakterije E. coli. Nijedan izolat nije pripadao serovaru O157:H7, na osnovi čega se može zaključiti da šišmiši na području Laguna i Quezon City na Filipinima nisu nositelji patogenog soja E. coli O157:H7. Istraživanje je ujedno prvi dokaz o izdvajanju i molekularnoj identifikaciji bakterije E. coli u šišmiša na Filipinima

Tissue-specific expression of high-voltage-activated dihydropyridine-sensitive L-type calcium channels

The cloning of the cDNA for the α1 subunit of L-type calcium channels revealed that at least two genes (CaCh1 and CaCh2) exist which give rise to several splice variants. The expression of mRNA for these α1 subunits and the skeletal muscle α2/δ, β and γ subunits was studied in rabbit tissues and BC3H1 cells. Nucleic-acid-hybridization studies showed that the mRNA of all subunits are expressed in skeletal muscle, brain, heart and aorta. However, the α1-, β- and γ-specific transcripts had different sizes in these tissues. Smooth muscle and heart contain different splice variants of the CaCh2 gene. The α1, β and γ mRNA are expressed together in differentiated but not in proliferating BC3H1 cells. A probe specific for the skeletal muscle α2/δ subunit did not hybridize to poly(A)-rich RNA from BC3H1 cells. These results suggest that different splice variants of the genes for the α1, β and γ subunits exist in tissues containing L-type calcium channels, and that their expression is regulated in a coordinate manner

Tephra sedimentation and grainsize associated with pulsatory activity: the 2021 Tajogaite eruption of Cumbre Vieja (La Palma, Canary Islands, Spain)

Long-lasting eruptions are of complex characterization and are typically associated with challenging risk assessment and crisis management due to the usual occurrence of multiple interacting hazards evolving at different temporal and spatial scales (e.g., lava, tephra, and gas). The 2021 Tajogaite eruption of Cumbre Vieja (La Palma) demonstrated how even hybrid events that are mostly effusive can be associated with widespread and impacting tephra deposits as a result of a complex interplay among gas flux, conduit geometry, and magma feeding rate. In this novel study, direct observations, syn-eruptive and post-eruptive sampling, and statistical analysis of pulsatory activity have been combined to provide new insights into eruption dynamics. They show how rapid gas segregation and high magma ascent rate modulated the gas flux at multiple vents, resulting in short-time fluctuations among the different explosive styles (ash-poor gas puffing, Strombolian, violent Strombolian, and lava fountaining) and unsteady tephra ground accumulation. Various size-selective sedimentation processes were also observed, including particle aggregation and ash fingers, which have impacted the overall tephra dispersal. In fact, even though both local and total grainsize distributions of selected layers, units, and of the whole tephra blanket are unimodal with a low fine-ash content, grainsize analysis of 154 samples suggests no correlation of particles <63 μm with distance from vents. Our analyses demonstrate the need to include a detailed characterization of all products of hybrid eruptions for a comprehensive interpretation of eruptive dynamics and to use multiple classification strategies that can capture eruptive styles at different temporal scales

Mass spectrometry imaging identifies palmitoylcarnitine as an immunological mediator during Salmonella Typhimurium infection

Salmonella Typhimurium causes a self-limiting gastroenteritis that may lead to systemic disease. Bacteria invade the small intestine, crossing the intestinal epithelium from where they are transported to the mesenteric lymph nodes (MLNs) within migrating immune cells. MLNs are an important site at which the innate and adaptive immune responses converge but their architecture and function is severely disrupted during S. Typhimurium infection. To further understand host-pathogen interactions at this site, we used mass spectrometry imaging (MSI) to analyse MLN tissue from a murine model of S. Typhimurium infection. A molecule, identified as palmitoylcarnitine (PalC), was of particular interest due to its high abundance at loci of S. Typhimurium infection and MLN disruption. High levels of PalC localised to sites within the MLNs where B and T cells were absent and where the perimeter of CD169+ sub capsular sinus macrophages was disrupted. MLN cells cultured ex vivo and treated with PalC had reduced CD4+CD25+ T cells and an increased number of B220+CD19+ B cells. The reduction in CD4+CD25+ T cells was likely due to apoptosis driven by increased caspase-3/7 activity. These data indicate that PalC significantly alters the host response in the MLNs, acting as a decisive factor in infection outcome

Estimation of the national disease burden of influenza-associated severe acute respiratory illness in Kenya and Guatemala : a novel methodology

Background: Knowing the national disease burden of severe influenza in low-income countries can inform policy decisions around influenza treatment and prevention. We present a novel methodology using locally generated data for estimating this burden. Methods and Findings: This method begins with calculating the hospitalized severe acute respiratory illness (SARI) incidence for children <5 years old and persons ≥5 years old from population-based surveillance in one province. This base rate of SARI is then adjusted for each province based on the prevalence of risk factors and healthcare-seeking behavior. The percentage of SARI with influenza virus detected is determined from provincial-level sentinel surveillance and applied to the adjusted provincial rates of hospitalized SARI. Healthcare-seeking data from healthcare utilization surveys is used to estimate non-hospitalized influenza-associated SARI. Rates of hospitalized and non-hospitalized influenza-associated SARI are applied to census data to calculate the national number of cases. The method was field-tested in Kenya, and validated in Guatemala, using data from August 2009–July 2011. In Kenya (2009 population 38.6 million persons), the annual number of hospitalized influenza-associated SARI cases ranged from 17,129–27,659 for children <5 years old (2.9–4.7 per 1,000 persons) and 6,882–7,836 for persons ≥5 years old (0.21–0.24 per 1,000 persons), depending on year and base rate used. In Guatemala (2011 population 14.7 million persons), the annual number of hospitalized cases of influenza-associated pneumonia ranged from 1,065–2,259 (0.5–1.0 per 1,000 persons) among children <5 years old and 779–2,252 cases (0.1–0.2 per 1,000 persons) for persons ≥5 years old, depending on year and base rate used. In both countries, the number of non-hospitalized influenza-associated cases was several-fold higher than the hospitalized cases. Conclusions: Influenza virus was associated with a substantial amount of severe disease in Kenya and Guatemala. This method can be performed in most low and lower-middle income countries