An important yet poorly understood facet in the life cycle of a successful pathogen is the host-to-host transmission. Hospital-acquired infections (HAI) resulting from the transmission of drug-resistant pathogens affect hundreds of millions of patients worldwide. Klebsiella pneumoniae (Kpn), a gram-negative bacterium, is notorious for causing HAI, with many of these infections difficult to treat as Kpn has become multi-drug resistant. Epidemiological studies suggest that Kpn host-to-host transmission requires close contact and generally occurs through the fecal-oral route. Herein, we describe a murine model that can be utilized to study mucosal (oropharynx and gastrointestinal [GI]) colonization, shedding within feces, and transmission of Kpn through the fecal-oral route. Using an oral route of inoculation, and fecal shedding as a marker for GI colonization, we show that Kpn can asymptomatically colonize the GI tract of immunocompetent mice, and modifies the host GI microbiota. Colonization density within the GI tract and levels of shedding in the feces differed among the clinical isolates tested. A hypervirulent Kpn isolate was able to translocate from the GI tract and cause hepatic infection that mimicked the route of human infection. Expression of the capsule was required for colonization and, in turn, robust shedding. Furthermore, Kpn carrier mice were able to transmit to uninfected cohabitating mice. Lastly, treatment with antibiotics led to changes in the host microbiota and development of a transient super-shedder phenotype, which enhanced transmission efficiency. Thus, this model can be used to determine the contribution of host and bacterial factors towards Kpn dissemination.

The biological cost associated with colistin resistance in Klebsiella pneumoniae was examined using a murine model of K. pneumoniae gut colonization and fecal-oral transmission. A common mutation resulting in colistin resistance in K. pneumoniae is a loss-of-function mutation of the small regulatory protein MgrB that regulates the two-component system PhoPQ.

The ability to sense and respond rapidly to the dynamic environment of the upper respiratory tract (URT) makes Streptococcus pneumoniae ( Spn ) a highly successful human pathogen. Two-component systems (TCSs) of Spn sense and respond to multiple signals it encounters allowing Spn to adapt and thrive in various host sites. Spn TCS have been implicated in their ability to promote pneumococcal colonization of the URT and virulence.

This intervention extends learning strategies research into authentic learning environments. It shows college biology students can learn to generate analogies as a learning strategy and get better at doing so. Finally, students’ generated-analogy quality predicts analogical reasoning and knowledge of cognition.

The ability to sense and respond rapidly to the dynamic environment of the upper respiratory tract (URT) makes Streptococcus pneumoniae (Spn) a highly successful human pathogen. Two-component systems (TCS) of Spn sense and respond to multiple signals it encounters allowing Spn to adapt and thrive in various host sites. Spn TCS have been implicated in their ability to promote pneumococcal colonization of the URT and virulence. As the disease state can be a dead-end for a pathogen, we considered whether TCS would contribute to pneumococcal transmission. Herein, we determined the role of YesMN, an understudied TCS of Spn, and observe that YesMN contributes towards pneumococcal shedding and transmission but is not essential for colonization. The YesMN regulon includes genes involved in zinc homeostasis and glycan metabolism, which are upregulated during reduced zinc availability in a YesMN dependent fashion. Thus, we identify the YesMN regulon and the molecular signals it senses that lead to the activation of genes involved in zinc homeostasis and glycan metabolism. Furthermore, in contract to Spn mono-infection, we demonstrate that YesMN is critical for high pneumococcal density in the URT during influenza A (IAV) coinfection. We attribute reduced colonization of the yesMN mutant due to increased association with and clearance by the mucus covering the URT epithelial surface. Thus, our results highlight the dynamic interactions that occur between Spn and IAV in the URT, and the role that TCS play in modulation of these interactions.

Due to its high transmissibility, Klebsiella pneumoniae (Kpn) is one of the leading causes of nosocomial infections. Here, we studied the biological cost of colistin resistance, an antibiotic of last resort, of this opportunistic pathogen using a murine model of gut colonization and transmission. Colistin resistance in Kpn is commonly the result of inactivation of the small regulatory protein MgrB. Without a functional MgrB, the two-component system PhoPQ is constitutively active, leading to increased lipid A modifications and subsequent colistin resistance. Using an engineered MgrB mutant, we observed that MgrB-dependent colistin resistance is not associated with a fitness defect during in vitro growth conditions. However, colistin-resistant Kpn colonizes the murine gut poorly, which may be due to the decreased production of capsular polysaccharide by the mutant. The colistin-resistant mutant of Kpn had increased survival outside the host when compared to the parental colistin-sensitive strain. We attribute this enhanced survivability to dysregulation of the PhoPQ two-component system and accumulation of the master stress regulator RpoS. The enhanced survival of the colistin resistant strain may be a key factor in the observed rapid host-to-host transmission in our model. Together, our data demonstrate that colistin-resistant Kpn experiences a biological cost in gastrointestinal colonization. However, this cost is mitigated by enhanced survival outside the host, increasing the risk of transmission. Additionally, it underscores the importance of considering the entire life cycle of a pathogen to truly determine the biological cost associated with antibiotic resistance.ImportanceThe biological cost associated with colistin resistance in Klebsiella pneumoniae (Kpn) was examined using a murine model of Kpn gut colonization and fecal-oral transmission. A common mutation resulting in colistin resistance in Kpn is a loss-of-function mutation of the small regulatory protein MgrB that regulates the two-component system PhoPQ. Even though colistin resistance in Kpn comes with a fitness defect in gut colonization, it increases bacterial survival outside the host enabling it to more effectively transmit to a new host. The enhanced survival is dependent upon the accumulation of RpoS and dysregulation of the PhoPQ. Hence, our study expands our understanding of the underlying molecular mechanism contributing to the transmission of colistin-resistant Kpn.

42An important yet poorly understood facet in the life cycle of a successful pathogen is the host-to-43 host transmission. Hospital-acquired infections (HAI) resulting from the transmission of drug-44 resistant pathogens affect hundreds of millions of patients worldwide. Klebsiella pneumoniae 45 (Kpn), a gram-negative bacterium, is notorious for causing HAI, with many of these infections 46 difficult to treat as Kpn has become multi-drug resistant. Epidemiological studies suggest that 47 Kpn host-to-host transmission requires close contact and generally occurs through the fecal-oral 48 route. Herein, we describe a murine model that can be utilized to study mucosal (oropharynx and 49 gastrointestinal [GI]) colonization, shedding within feces, and transmission of Kpn through the 50 fecal-oral route. Using an oral route of inoculation, and fecal shedding as a marker for GI 51 colonization, we show that Kpn can asymptomatically colonize the GI tract of immunocompetent 52 mice, and modifies the host GI microbiota. Colonization density within the GI tract and levels of 53 shedding in the feces differed among the clinical isolates tested. A hypervirulent Kpn isolate was 54 able to translocate from the GI tract and cause hepatic infection that mimicked the route of 55 human infection. Expression of the capsule was required for colonization and, in turn, robust 56 shedding. Furthermore, Kpn carrier mice were able to transmit to uninfected cohabitating mice. 57 Lastly, treatment with antibiotics led to changes in the host microbiota and development of a 58 transient super-shedder phenotype, which enhanced transmission efficiency. Thus, this model 59 can be used to determine the contribution of host and bacterial factors towards Kpn 60 dissemination. 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77Introduction. 79Host-to-host transmission of pathogens is the primary source of nosocomial infections, 80 which are considered a serious threat to patient's health and also a significant burden on the 81 healthcare system (1, 2). Hospital-acquired infections (HAI) account for ~100,000 deaths in the 82 United States alone (3). A leading cause of these hospital-acquired infections and multiple 83 outbreaks in hospitals around the world is Klebsiella pneumoniae (K. pneumoniae; Kpn), a 84 member of the Enterobacteriaceae family that frequently causes pneumonia, bacteremia, 85 pyogenic liver abscesses, and urinary tract infections (4), with most of these infections generally 86 occuring in immunocompromised patients. With the rampant use of antibiotics Kpn isolates have 87 become extensively drug-resistant, and some are now even considered pan-drug resistant, 88 making the infections they cause extremely difficult to treat (5-7). For this reason, WHO 89 lists Klebsiella pneumoniae as a critical pathogen for which new antibiotics and other therapies 90are urgently required to address this growing healthcare problem (8, 9). Further exacerbating 91 treatment of Kpn infections is the recent identification of isolates termed "hyperv...

In this chapter, we explore how faculty employ the use of gamification and game‐based learning environments (GBLE) in postsecondary education. Gamification refers to the use of game‐design elements while game‐based learning refers to the use of digital education games. Both are increasingly popular instructional practices and, in this chapter, we specifically examine their potential for supporting students’ self‐regulated learning (SRL). Important for academic success, SRL refers to the active, cyclical process of intentionally directing one's metacognition, motivation, and behavior to achieve a learning goal. Findings from the extant research on gamification and GBLEs conducted in postsecondary settings are reported with connections to SRL processes throughout. Furthermore, we review the effects of games on varied learning, motivation, and SRL outcomes. Finally, we conclude with recommendations for future research and practice, with a primary suggestion of more explicitly addressing SRL in research related to gamification and game‐based learning.