221. Evaluation of Rates of Culture Positive Blood Stream Pathogens Prior to and During the SARS-CoV-2 Pandemic: A Multicenter Evaluation

Background Bacterial co-infections or super-infections are well-characterized complications of viral infections, further increasing morbidity and mortality of global viral pandemics. We evaluated trends in the incidence of culture positive gram-negative (GN), gram-positive (GP), and fungal/yeast pathogens from a blood source in hospitalized patients at US hospitals before and during the SARS-CoV-2 pandemic. Table: Incidence and rate of blood pathogens in the pre and post SARS-CoV-2 period. Gray indicates significantly lower rate compared to pre-pandemic time period, black indicates significantly higher rates compared to pre-pandemic. Methods: This was a multi-center, retrospective cohort analysis of all hospitalized patients from 267 US acute care facilities with >1-day inpatient admission between 7/1/19-5/19/21 (BD Insights Research Database [Becton, Dickinson and Company, Franklin Lakes, NJ]). SARS-CoV-2 infection was identified by a positive PCR during or ≤7 days prior to hospitalization. All admissions with a non-contaminant culture positive GN, GP, and fungal/yeast pathogen from a blood source were evaluated prior to and during the SARS-CoV-2 pandemic as rates per 1,000 admissions (p< .05 for significance). Results There were 2,001,793 admissions in the pre-SARS-CoV-2 period (7/2019-2/2020) and 2,875,219 admissions during the SARS-CoV-2 pandemic. Incidence of GN/GP blood stream pathogens was significantly higher prior to the SARS-CoV-2 pandemic than during the pandemic. Higher rates of blood stream pathogens occurred in those who were tested for SARS-CoV-2, but all non-tested patients had significantly lower rates than pre-pandemic. Rates of Candida spp., Enterococcus spp., Serratia marcescens, and Enterobacter cloacae were higher in SARS-CoV-2 positive patients compared to pre-pandemic patients. Compared to the prior pandemic period, the incidence of B. fragilis, Streptococcus, Enterococcus and Candida were higher among those tested for SARS-CoV-2 but were negative. Conclusion In general, rates of positive blood cultures for bacterial pathogens were either lower or similar during the SARS-CoV-2 period compared to the pre-SARS-CoV-2 pandemic period. The patients that were tested for SARS-CoV-2 but were positive who had higher rates of infection than prior may indicate the similarity in viral and bacterial clinical presentation. Further evaluation of higher rates of Enterococcus and Candida in the pandemic period are warranted. Disclosures Laura A. Puzniak, PhD, Merck & Co., Inc. (Employee) Karri A. Bauer, PharmD, Merck & Co., Inc. (Employee, Shareholder) Kalvin Yu, MD, BD (Employee) Pamela Moise, PharmD, Merck (Employee) Vikas Gupta, PharmD, BCPS, Becton, Dickinson and Company (Employee, Shareholder)

The Immune System of the Human Body in Defense against Cancer

This study has discovered a new mechanism that involves inhibiting the organelle, the lysosome, and dormant that cell. This opens the way for lysosomes to potentially be used as a therapeutic target. Tens of thousands of people around the world receive bone marrow transplants each year to help treat leukemia. High doses of chemotherapy are used to quickly kill cancer cells, but they also kill the stem cells needed to reproduce healthy blood. Stem cell transplantation is used to regenerate a patient's healing blood source, but finding the right donor can be challenging, especially in different ethnic communities where the donor list may not be extensive or non-existent. Stem cells in cord blood are of considerable value as additional donor sources, but the number of stem cells is often too small for an adult recipient. Understanding how stem cells are activated and proliferated in a controlled manner can greatly benefit cord blood. The ability to control stem cell activation may also be helpful in situations where stem cells are improperly activated due to disease, inflammation, or drug treatment, and help maintain sleep. Learning how to maintain blood stem cells is essential. If that stem cell is activated improperly, it can have serious consequences for the blood system, because stem cells are not renewable. You have to do everything you can to keep that cell asleep, and one way is to block signals from its surface. It can also be used to help fully understand leukemia stem cells, which mimic normal stem cells and are sometimes able to sleep and escape treatment. It is now interesting to look at these leukemia stem cells and see how this mechanism is regulated. We may notice differences and use them for treatment. Keywords: Cancer; Cells; Tissues; Tumors; Prevention; Prognosis; Diagnosis; Imaging; Screening; Treatment; Management

Detection Molecular of Leishmania Spp. And Blood Source in Female Sand Flies in the Parque Estadual Do Rio Doce and in the Municipality of Timóteo, Minas Gerais, Brazil.

Background: Leishmaniasis is a set of diseases caused by protozoa of the Leishmania genus (Kinetoplastida: Trypanosomatidae) and transmitted by the bite of female sand fly insects (Diptera: Psychodidae). The present work was characterized as a descriptive study comparing two areas: a wild area where the Parque Estadual do Rio Doce (PERD) is located and another urban area, located in the municipality of Timóteo-MG (AUT). Aiming to identify the presence of Leishmania spp. and the blood source of collected female sand flies. Methods: Sand flies were collected with CDC light trap model HP, between September 2012 and February 2014. We used 19 traps in the Urban Area of ​​Timóteo and 12 in the Rio Doce State Park. For molecular studies of Leishmania spp. DNA we used ITS1 gene and in the search of blood source, with naturally fed females, the CytB gene was used and positive samples were sequenced. Results: It was clear that in the municipality of Timóteo there are at least three species of Leishmania: Leishmania (Viannia) braziliensis, Leishmania (Leishmania) amazonensis and Leishmania (V.) guyanensis. A large presence of Leishmania braziliensis DNA was identified in female sand flies. Nyssomyia whitmani was the most captured species in the urban area, while in the PERD it was Pressatia choti, both species were positive for the presence of Leishmania braziliensis DNA. And last but not least was the record of the participation of Gallus gallus (chicken) and Sus scrofa (pig) as a blood source for sandflies, which helps to maintain the life cycle of vectors in the urban area of ​​the municipality.Conclusion: The present study demonstrates that Leishmania braziliensis is the main tegumentary leishmaniasis transmitter agent in the study area, with effective participation of Nyssomyia whitmani as a vector. And it draws attention to the possibility that Gallus gallus (chicken) and Sus scrofa (pig) are fundamental in maintaining the cycle in urban areas.

The Common Bed Bug (Hemiptera: Cimicidae) Does Not Commonly Use Canines and Felines as a Host in Low-Income, High-Rise Apartments

The common bed bug (Cimex lectularius L.) is a known pest and an obligate blood-feeding ectoparasite. Bed bugs can feed on warm-blooded animals including humans, bats, poultry, and rabbits, but no research has investigated the use of companion animals (canines and/or felines) as a blood source. This study investigates how long known host DNA could be detected in a bed bug and the prevalence of bed bugs feeding on companion animals. Laboratory-reared bed bugs were fed host blood to determine how long DNA of human, feline, canine, and rabbit blood could be detected up to 21 d postfeeding. Additionally, 228 bed bugs were collected from 12 apartments with pets (6: canine, 5: feline, and 1: canine and feline), characterized as engorged or unengorged, and then screened with host-specific primers to identify the bloodmeal. Host meals of human, rabbit, feline, and canine blood were detected up to 21 d after feeding laboratory strains. All bed bugs died after feeding on the canine blood, but DNA could be detected up to 21 d post feeding/death. Of the field-collected bed bugs analyzed, human DNA was amplified in 158 (69.3%) bed bugs, canine DNA amplified in 7 bed bugs (3.1%), and feline DNA amplified in 1 bed bug (0.4%). Results of this study suggest that bed bugs predominately feed on humans and rarely feed on companion animals when they cohabitate in low-income, high-rise apartments. Additionally, results from this study warrant future investigations into host use by bed bugs in different housing structures and socioeconomic environments.

Dose–Response Assay for Synthetic Mosquito (Diptera: Culicidae) Attractant Using a High-Throughput Screening System

Natural volatile host cues play a critical role for mosquito orientation and locating a blood source for egg production. Similar olfactory activation responses have allowed the use and development of artificial chemical attractants to lure mosquitoes to trapping devices. Using a pre-formulated commercial product mixture of different attractant chemicals, a high-throughput screening system (HITSS) is used to screen varying doses of chemical required to activate behavioral responses. Two strains of Aedes aegypti (L.): permethrin-susceptible (USDA) and -resistant (Pu Teuy) phenotypes and one Culex quinquefasciatus Say. (NIH) laboratory strain were tested. Overall, mosquitoes showed repellency between 1.0 g and to 10.0 g dose of each compound. However, by progressively reducing the dose, Cx. quinquefasciatus showed a greater positive percent attraction (88.9%) at 0.025 g, whereas the USDA and Pu Teuy Ae. aegypti produced optimum attractant activation at 0.005 g (72.6% and 58.9%, respectively) without significant difference within species (p > 0.05). In parallel control assays, Cx. quinquefasciatus was significantly attracted to 1 g of dry ice (carbon dioxide) (76%) more than Ae. aegypti (USDA) (12.2%). The HITSS was originally designed to measure three chemical actions to sublethal concentrations of chemicals by mosquitoes: toxicity and the two primary behavior avoidance responses (contact excitation and spatial repellency). These findings demonstrate that the HITSS assay, with only minor modifications, allows comparison screening of candidate compounds as potential attractants for anemotactic responses under laboratory-controlled conditions. Further investigations will be required to equate measurements obtained from controlled laboratory assays to more varied field conditions for attracting natural mosquito populations.

Effect of blood source on vector competence of Culex pipiens biotypes for Usutu virus

Background Infectious blood meal experiments have been frequently performed with different virus-vector combinations to assess the transmission potential of arthropod-borne (arbo)viruses. A wide variety of host blood sources have been used to deliver arboviruses to their arthropod vectors in laboratory studies. The type of blood used during vector competence experiments does not always reflect the blood from the viremic vertebrate hosts in the field, but little is known about the effect of blood source on the experimental outcome of vector competence studies. Here we investigated the effect of avian versus human blood on the infection and transmission rates of the zoonotic Usutu virus (USUV) in its primary mosquito vector Culex pipiens. Methods Cx. pipiens biotypes (pipiens and molestus) were orally infected with USUV through infectious blood meals containing either chicken or human whole blood. The USUV infection and transmission rates were determined by checking mosquito bodies and saliva for USUV presence after 14 days of incubation at 28 °C. In addition, viral titers were determined for USUV-positive mosquito bodies and saliva. Results Human and chicken blood lead to similar USUV transmission rates for Cx. pipiens biotype pipiens (18% and 15%, respectively), while human blood moderately but not significantly increased the transmission rate (30%) compared to chicken blood (17%) for biotype molestus. USUV infection rates with human blood were consistently higher in both Cx. pipiens biotypes compared to chicken blood. In virus-positive mosquitoes, USUV body and saliva titers did not differ between mosquitoes taking either human or chicken blood. Importantly, biotype molestus had much lower USUV saliva titers compared to biotype pipiens, regardless of which blood was offered. Conclusions Infection of mosquitoes with human blood led to higher USUV infection rates as compared to chicken blood. However, the blood source had no effect on the vector competence for USUV. Interestingly, biotype molestus is less likely to transmit USUV compared to biotype pipiens due to very low virus titers in the saliva.

Opportunistic feeding behaviour and Leishmania infantum detection in Phlebotomus perniciosus females collected in the human leishmaniasis focus of Madrid, Spain (2012–2018)

Background An outbreak of human leishmaniasis due to Leishmania infantum has been registered in an urban area of southwestern Madrid, Spain, since 2010. Entomological surveys carried out in the municipalities of Fuenlabrada, Leganés, Getafe and Humanes de Madrid showed that Phlebotomus perniciosus is the only potential vector. In this work, an intensive molecular surveillance was performed in P. perniciosus females captured in the region between 2012 and 2018. Methodology/Principal findings A total of 1805 P. perniciosus females were analyzed for Leishmania infection, and 1189 of them also for bloodmeal identification. Eleven different species of vertebrate were detected by amplification and subsequent sequencing of the 359 bp cytb fragment. The most prevalent blood source identified was hare (n = 553, 46.51%), followed by rabbit (n = 262, 21.95%). Less frequent were cat (n = 45, 3.80%), human (n = 34, 2.90%), pig (n = 14, 1.20%), horse (n = 11, 0.93%), sheep (n = 3, 0.25%), rhea (n = 3, 0.25%), partridge (n = 1, 0.09%) and chicken (n = 1, 0.09%). The distribution of the blood meal sources varied between the different locations. Regarding L. infantum detection, PCR amplification of a fragment of kDNA, cpb gene and ITS1 region showed 162 positive specimens (8.97%). The highest infection rate was found in the municipality of Leganés (15.17%). Conclusions The results of this molecular survey in P. perniciosus, the only leishmaniasis vector in the outbreak occurred in southwestern Madrid region, showed its opportunistic blood-feeding behaviour, high infection rates and the differences between the different points. This study was an essential part of the intensive surveillance plan in the area and the results obtained have supported the implementation of control measures in the outbreak.

Tick Microbiomes in Neotropical Forest Fragments Are Best Explained by Tick-Associated and Environmental Factors Rather Than Host Blood Source

The composition of tick microbiomes varies both within and among tick species. Whether this variation is intrinsic (related to tick characteristics), or extrinsic (related to vertebrate host and habitat) is poorly understood but important, as microbiota can influence the reproductive success and vector competence of ticks. We aimed to uncover what intrinsic and extrinsic factors best explain the microbial composition and taxon richness of 11 species of Neotropical ticks, collected from eight species of small mammals in 18 forest fragments across central Panama. Microbial richness varied among tick species, life stages, and collection sites, but was not related to host blood source. Microbiome composition was best explained by tick life stage, with bacterial assemblages of larvae being a subset of those of nymphs. Collection site explained most of the bacterial taxa with differential abundance across intrinsic and extrinsic factors. Francisella and Rickettsia were highly prevalent, but their proportional abundance differed greatly among tick species and we found both positive and negative co-occurrence between members of these two genera. Other tick endosymbionts (e.g. Coxiella, Rickettsiella) were associated with specific tick species. In addition, we detected Anaplasma and Bartonella in several tick species. Our results indicate that the microbial composition and richness of Neotropical ticks are principally related to intrinsic factors (tick species, life stage) and collection site. Taken together, our analysis informs how tick microbiomes are structured and can help anchor our understanding of tick microbiomes from tropical environments more broadly. Importance: Blood feeding insect microbiomes often play important roles in disease transmission, yet the factors that structure tick microbial communities in the Neotropics are unknown. Utilizing ticks collected from live animals in Neotropical Forest Fragments, this study teases apart the contributions of intrinsic and extrinsic tick-associated factors on tick microbial composition, as well as which specific microbes contribute to differences across tick species, tick lifestages, mammals they fed on, and the locations from where they were sampled. Furthermore, this study provides revelations of how notable tick-associated bacterial genera are interacting with other tick-associated microbes, as well as and the forest animals they encounter.