A fatal outbreak of neonatal sepsis caused by mcr-10-carrying Enterobacter kobei in a tertiary care hospital in Nepal.

BACKGROUND: Enterobacter kobei is an emerging cause of outbreak of nosocomial infections in neonatal intensive care units (NICUs). Between July and September 2016, a NICU in a tertiary care hospital of Nepal observed an abrupt increase in the number of neonatal sepsis cases caused by Enterobacter spp. infecting 11 out of 23 admitted neonates, five of whom died of an exacerbated sepsis. AIM: To confirm the suspected outbreak, identify environmental source of infection, and characterize genetic determinants of antimicrobial resistance (AMR) and virulence of the pathogen. METHODS: Whole-genome sequencing of all Enterobacter spp. isolated from blood cultures of septic neonates admitted to NICU between May 2016 and December 2017 was performed. Also, an environmental sampling was intensified from fortnightly to weekly during the outbreak. FINDINGS: The genomic analysis revealed that 10 out of 11 non-duplicated E. kobei isolated from neonatal blood cultures between July and September 2016 were clonal, confirming the outbreak. The isolates carried AMR genes including blaAmpC and mcr-10 conferring reduced susceptibility to carbapenem and colistin respectively. The environmental sampling, however, failed to isolate any Enterobacter spp. Reinforcement of aseptic protocols in invasive procedures, hand hygiene, environmental decontamination, fumigation, and secluded care of culture-positive cases successfully terminated the outbreak. CONCLUSION: Our study underscored the need to implement stringent infection control measures to prevent infection outbreaks. For the first time, we report the emergence of carbapenem and colistin non-susceptible E. kobei carrying mcr-10 gene as a cause of nosocomial neonatal sepsis in a NICU.

Emerging Insights into the Impact of Air Pollution on Immune-Mediated Asthma Pathogenesis.

PURPOSE OF REVIEW: Increases in ambient levels of air pollutants have been linked to lung inflammation and remodeling, processes that lead to the development and exacerbation of allergic asthma. Conventional research has focused on the role of CD4+ T helper 2 (TH2) cells in the pathogenesis of air pollution-induced asthma. However, much work in the past decade has uncovered an array of air pollution-induced non-TH2 immune mechanisms that contribute to allergic airway inflammation and disease. RECENT FINDINGS: In this article, we review current research demonstrating the connection between common air pollutants and their downstream effects on non-TH2 immune responses emerging as key players in asthma, including PRRs, ILCs, and non-TH2 T cell subsets. We also discuss the proposed mechanisms by which air pollution increases immune-mediated asthma risk, including pre-existing genetic risk, epigenetic alterations in immune cells, and perturbation of the composition and function of the lung and gut microbiomes. Together, these studies reveal the multifaceted impacts of various air pollutants on innate and adaptive immune functions via genetic, epigenetic, and microbiome-based mechanisms that facilitate the induction and worsening of asthma.

Novel Mechanisms of Ozone-Induced Pulmonary Inflammation and Resolution, and the Potential Protective Role of Scavenger Receptor BI.

INTRODUCTION: Increases in ambient levels of ozone (O3), a criteria air pollutant, have been associated with increased susceptibility and exacerbations of chronic pulmonary diseases through lung injury and inflammation. O3 induces pulmonary inflammation, in part by generating damage-associated molecular patterns (DAMPs), which are recognized by pattern recognition receptors (PRRs), such as toll-like receptors (TLRs) and scavenger receptors (SRs). This inflammatory response is mediated in part by alveolar macrophages (AMs), which highly express PRRs, including scavenger receptor BI (SR-BI). Once pulmonary inflammation has been induced, an active process of resolution occurs in order to prevent secondary necrosis and to restore tissue homeostasis. The processes known to promote the resolution of inflammation include the clearance by macrophages of apoptotic cells, known as efferocytosis, and the production of specialized pro-resolving mediators (SPMs). Impaired efferocytosis and production of SPMs have been associated with the pathogenesis of chronic lung diseases; however, these impairments have yet to be linked with exposure to air pollutants. SPECIFIC AIMS: The primary goals of this study were: Aim 1 - to define the role of SR-BI in O3-derived pulmonary inflammation and resolution of injury; and Aim 2 - to determine if O3 exposure alters pulmonary production of SPMs and processes known to promote the resolution of pulmonary inflammation and injury. METHODS: To address Aim 1, female wild-type (WT) and SR-BI-deficient, or knock-out (SR-BI KO), mice were exposed to either O3 or filtered air. In one set of experiments mice were instilled with an oxidized phospholipid (oxPL). Bronchoalveolar lavage fluid (BALF) and lung tissue were collected for the analyses of inflammatory and injury markers and oxPL. To estimate efferocytosis, mice were administered apoptotic cells (derived from the Jurkat T cell line) after O3 or filtered air exposure.To address Aim 2, male WT mice were exposed to either O3 or filtered air, and levels of SPMs were assessed in the lung, as well as markers of inflammation and injury in BALF. In some experiments SPMs were administered before exposure to O3or filtered air, to determine whether SPMs could mitigate inflammatory or resolution responses. Efferocytosis was measured as in Aim 1. RESULTS: For Aim 1, SR-BI protein levels increased in the lung tissue of mice exposed to O3, compared with mice exposed to filtered air. Compared with WT controls, SR-BI KO mice had a significant increase in the number of neutrophils in their airspace 24 hours post O3 exposure. The oxPL levels increased in the airspace of both WT and SR-BI KO mice after O3 exposure, compared with filtered air controls. Four hours after instillation of an oxPL, SR-BI KO mice had an increase in BALF neutrophils and total protein, and a nonsignificant increase in macrophages compared with WT controls. O3 exposure decreased efferocytosis in both WT and SR-BI KO female mice.For Aim 2, mice given SPM supplementation before O3 exposure showed significantly increased AM efferocytosis when compared with the O3exposure control mice and also showed some mitigation of the effects of O3 on inflammation and injury. Several SPMs and their precursors were measured in lung tissue using reverse-phase high performance liquid chromatography (HPLC) with tandem mass spectrometry (MS/MS). At 24 hours after O3 exposure 14R-hydroxydocosahexaenoic acid (HDHA) and 10,17-dihydroxydocosahexaenoic acid (diHDoHE) were significantly decreased in lung tissue, but at 6 hours after exposure, levels of these SPMs increased. CONCLUSIONS: Our findings identify novel mechanisms by which O3 may induce pulmonary inflammation and also increase susceptibility to and exacerbations of chronic lung diseases.

Acute high-altitude illness.

Letter by Basnyat on article by Hofmeyr et al. (Hofmeyr R, Tölken G, De Decker R. Acute high-altitude illness. S Afr J Med 2017;107(7):556-561. https://doi.org/10.7196/SAMJ.2017.v107i7.12612); and response by Hofmeyr et al.

Electrostatic dust collectors compared to inhalable samplers for measuring endotoxin concentrations in farm homes.

Paired electrostatic dust collectors (EDCs) and daily, inhalable button samplers (BS) were used concurrently to sample endotoxin in 10 farm homes during 7-day periods in summer and winter. Winter sampling included an optical particle counter (OPC) to measure PM2.5 and PM2.5-10 . Electrostatic dust collectors and BS filters were analyzed for endotoxin using the kinetic chromogenic Limulus amebocyte lysate assay. Optical particle counter particulate matter (PM) data were divided into two PM categories. In summer, geometric mean (geometric standard deviation) endotoxin concentrations were 0.82 EU/m(3) (2.7) measured with the BS and 737 EU/m(2) (1.9) measured with the EDC. Winter values were 0.52 EU/m(3) (3.1) for BS and 538 EU/m(2) (3.0) for EDCs. Seven-day endotoxin values of EDCs were highly correlated with the 7-day BS sampling averages (r = 0.70; P < 0.001). Analysis of variance indicated a 2.4-fold increase in EDC endotoxin concentrations for each unit increase of the ratio of PM2.5 to PM2.5-10 . There was also a significant correlation between BS and EDCs endotoxin concentrations for winter (r = 0.67; P < 0.05) and summer (r = 0.75; P < 0.05). Thus, EDCs sample comparable endotoxin concentrations to BS, making EDCs a feasible, easy to use alternative to BS for endotoxin sampling.

Antibiotic Use, Its Resistance in Nepal and Recommendations for Action: A Situation Analysis.

Antibiotics are crucial, life-saving medicines in the fight against infectious disease, but resistance to these drugs is growing all over. This article presents key findings from a detailed situation analysis produced by the Global Antibiotic Resistance Partnership (GARP)-Nepal working group. In the absence of nationally-representative surveillance, it is not possible to fully describe antibiotic resistance in the country, but many important bacterial pathogens are highly resistant to most first-line and some second-line antibiotics, according to available reports. In credible studies, more than half of Escherichia coli, Klebsiella pneumoniae and Streptococcus pneumoniae isolates tested, and over 30 percent of some Shigella spp. and Vibrio cholerae isolates were resistant to first-line antibiotics. The findings for Neisseria gonorrheae and hospital-acquired Staphylococcus aureus are similar. Antibiotic use in animal food is poorly documented in Nepal, but it is commonly acknowledged to be widespread, contributing to the overall antibiotic resistance burden. The volume of veterinary antibiotic sales in Nepal rose over 50 percent from 2008 to 2012, most through retailers without veterinarian prescription. Antibiotics are necessary to treat infections in animals, but they are also used extensively for preventing disease, a use that can be restricted without jeopardizing animal or human health. They may also be used for promoting animal growth, which can be eliminated with no health consequences. Nepal has made important advances in reducing mortality and morbidity and increasing health coverage, but has not yet taken steps to address antibiotic resistance. The GARP-Nepal working group outlines the components of a national strategy on antibiotic resistance, consistent with the recent call by the World Health Organization for national action plans, to be developed collaboratively with stakeholders and partners from government and all relevant sectors.

Cardiovascular function in healthy Himalayan high-altitude dwellers.

BACKGROUND: Residents of the Himalayan valleys uniquely adapted to their hypoxic environment in terms of pulmonary vasculature, but their systemic vascular function is still largely unexplored. The aim of the study was to investigate vascular function and structure in rural Sherpa population, permanently living at high altitude in Nepal (HA), in comparison with control Caucasian subjects (C) living at sea level. METHODS AND RESULTS: 95 HA and 64 C were enrolled. Cardiac ultrasound, flow-mediated dilation (FMD) of the brachial artery, carotid geometry and stiffness, and aortic pulse wave velocity (PWV) were performed. The same protocol was repeated in 11 HA with reduced FMD, after 1-h 100% O2 administration. HA presented lower FMD (5.18 ± 3.10 vs. 6.44  ±  2.91%, p = 0.02) and hyperemic velocity than C (0.61 ± 0.24 vs. 0.75 ± 0.28 m/s, p = 0.008), while systolic pulmonary pressure was higher (29.4 ± 5.5 vs. 23.6 ± 4.8 mmHg, p < 0.0001). In multiple regression analysis performed in HA, hyperemic velocity remained an independent predictor of FMD, after adjustment for baseline brachial artery diameter, room temperature and pulse pressure, explaining 8.7% of its variance. On the contrary, in C brachial artery diameter remained the only independent predictor of FMD, after adjustment for confounders. HA presented also lower carotid IMT than C (0.509 ± 0.121 vs. 0.576 ± 0.122 mm, p < 0.0001), higher diameter (6.98 ± 1.07 vs. 6.81 ± 0.85 mm, p = 0.004 adjusted for body surface area) and circumferential wall stress (67.6 ± 13.1 vs. 56.4 ± 16.0 kPa, p < 0.0001), while PWV was similar. O2 administration did not modify vascular variables. CONCLUSIONS: HA exhibit reduced NO-mediated dilation in the brachial artery, which is associated to reduced hyperemic response, indicating microcirculatory dysfunction. A peculiar carotid phenotype, characterized by reduced IMT and enlarged diameter, was also found.

Association between human polymorphic DNA markers and hypoxia adaptation in Sherpa detected by a preliminary genome scan.

Genetic determinants of resistance to hypobaric hypoxia in the Sherpa are still unknown. Since adaptive gene variants must still be subjected to positive selection, linkage disequilibrium between such variants and specific alleles of flanking DNA markers is expected. Following this line of reasoning, we performed a human genome scan using 998 polymorphic DNA markers in 7 unrelated Sherpa porters living in the Solu-Khumbu area. This minimalist approach succeeded in detecting 8 DNA markers showing homozygosity for the same shared allele. Analysis of additional DNA samples from 2 more Sherpa porters focused our attention on three polymorphic DNA markers (D6S1697, D14S274, D17S1795) showing homozygosity for the same shared allele in 8 out 9 tested individuals. Analysis of DNA samples from Sherpa and non-Sherpa populations of Nepal proved HW equilibrium in both populations for markers D14S274 and D17S1795, while an excess of heterozygotes was observed in the Sherpa population for marker D6S1697. A significant difference in allele frequencies for D14S274 and D17S1795 between the two populations was observed. These findings exclude the possibility that homozygosity for 3 specific loci in 8 unrelated individuals might be ascribed to inbreeding or recent genetic drift. We therefore conclude that the chromosomal segments detected by such DNA markers may include genes involved in adaptation to hypobaric hypoxia.

Acute mountain sickness, dehydration, and bicarbonate clearance: preliminary field data from the Nepal Himalaya.

BACKGROUND: In 1999, Basnyat et al. published preliminary data demonstrating an inverse correlation between hydration status and acute mountain sickness during an epidemiological study performed in the vicinity of Mount Everest. To expand on these findings, we have re turned to the Langtang area of the Nepal Himalaya to perform more specific studies of altitude illness related to dehydration and hypoxemia using urine studies, pulse oximetry, and physical examination. HYPOTHESIS: Dehydration will incite physiological changes aimed at the preservation of vascular volume homeostasis characterized by the production of sodium and water sparing hormones. As sodium is reabsorbed in the kidney, bicarbonate anion is also reabsorbed resulting in insufficient bicarbonate anion excretion by the kidney leading to an incomplete compensation for altitude induced hypocapnic alkalosis and the development of clinical disease. METHODS: Estimates of intravascular volume (urine specific gravity), oxygen saturation (pulse oximetry), urinary bi carbonate excretion (urine pH), and AMS (Lake Louise Score) were collected from Hindu pilgrims at 4243 m during an annual sacred festival at Lake Gosinkunda. RESULTS: Worsening altitude illness approx imated by increasing Lake Louise Score was associated with increasing urine specific gravity (p = 0.043), decreasing oxygen saturation (p = 0.020), and decreasing urine pH (p = 0.040) after rapid ascent to 4243 m. CONCLUSIONS: Worsening altitude illness, indicated by increasing Lake Louise score, was associated with increasing measures of dehydration, hypoxemia, and urine acidity.

Infections at high altitude.

Every year, thousands of outdoor trekkers worldwide visit high-altitude (>2500 m) destinations. Although high-altitude areas per se do not harbor any specific agents, it is important to know the pathogens encountered in the mountains to be better able to help the ill sojourner at high altitude. These are the same pathogens prevalent in the surrounding lowlands, but various factors such as immunomodulation, hypoxia, physiological adaptation, and harsh environmental stressors at high altitude may enhance susceptibility to these pathogens. Against this background, various gastrointestinal, respiratory, dermatological, neurological, and other infections encountered at high altitude are discussed. Because there are few published data on infections at high altitude, this review is largely anecdotal and based on personal experience.

Isolated facial and hypoglossal nerve palsies at high altitude.

A variety of neurological disorders other than high altitude cerebral edema have been described at high altitude. This report documents isolated facial and hypoglossal nerve palsies that occurred in two travellers at high altitude in the Nepal Himalaya. The possible pathophysiological mechanisms of these neurological deficits are discussed.