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The immune system rapidly mounts an innate immune response to invading pathogens that is accompanied by antigen-presentation, to promote the development of the adaptive immune response. These responses orchestrate through signal transduction by PRRs that recognize PAMPs, which results in the expression of various cytokines and mediators to promote pathogen control. Herein, we investigated the role of the type I interferon (IFN)- and the p38MAPK- pathways in response to infection with Salmonella Typhimurium (ST). We delved into the mechanisms through which IFNAR1-signaling results in host susceptibility against ST and show that while STAT2 and IRF9 promote susceptibility against ST, this is antagonized by STAT1. Our results indicate that IFNAR1-signaling induces IL-10 production through the ISGF3 complex, which indeed inhibits the production of IL-1β (via NLRP3 and caspase-1) resulting in a state of resistance against ST. Furthermore, our work elucidates that MK2, which is a p38MAPK substrate promotes host resistance, which is contradictory to type I IFNs despite the fact that MK2 regulates cytokine expression in a similar pattern to IRF9. We demonstrate that MK2 inhibits inflammasome signaling via NLRP3, caspase-1 and caspase11. We also reveal a role for MK2 in regulating IL-1β production via distinct signaling pathways including inhibition of MSK1/2 besides activation of the autophagic machinery; which also contribute to the enhanced inflammasome activation seen in Mk2- deficient cells. Thus, our observations illuminate the fact that the type I IFN pathway and the p38MAPK pathway are only dependent on each other to a certain extent in modulating the innate immune response to Salmonella infection, thereby bringing about varied outcomes in the infected host.

Healthcare and ancillary workers in hospital settings are at an increased risk of Tuberculosis (TB) due to the nature of their job and exposure to persons with TB. Knowledge of healthcare workers (HCWs), (physicians, residents, nurses, midlevels etc.) who provide direct care and ancillary staff (technicians, aides, administrators, etc.) who provide indirect care in medical institutions play an important role in the diagnosis, treatment, control, and prevention of TB. Research has shown a variation in knowledge based on TB prevalence, facility type, available resources, provider training and clinical experience, education level of staff, etc. The purpose of this study is to assess the knowledge of TB among HCWs and ancillary staff in an underserved medical institution who provide care to low-income populations in the United States. This is a cross sectional observational study. A validated questionnaire that assesses TB knowledge will be used. Participants from a historically black college in Tennessee will be recruited in the study. Participants will include HCWs such as attending physicians and residents from all residency programs as well as nurses, midlevels, etc. within the institution. We will also recruit ancillary staff in the same departments. The survey will be distributed between Jan. 2018-Feb. 2018, and will contain 10 questions. Information on demographics, work history (age, sex, education, job category, duration of employment, training level) and TB knowledge (general information on TB) will be captured. The survey will be distributed via email through RedCap, a secure web application for creating and managing online surveys. Emails of participants will be obtained through the institution’s employee and student directory. A minimum of 200 participants will be surveyed, to obtain a power of 80% and CI of 95%. Survey will be entered into the REDCap electronic research database and entered data from participants will be checked for completeness and accuracy. Knowledge will be assessed as: poor (75%-85% correct); and outstanding (>85% correct). We will compare differences in TB knowledge of HCWs and ancillary staff and between practicing physicians and physicians in training. Data analysis will be performed using R software. The expected results are that healthcare workers have higher knowledge level than ancillary workers and that practicing physicians have higher knowledge level than physicians in training due to years of clinical experience and education. As TB continues to be one of the leading causes of death worldwide, it is important that HCWs exhibit a good level of knowledge. The findings from this study will generate data to guide TB education efforts for providers and healthcare facility ancillary staff. Results will help to clarify misconceptions about TB transmission and enhance the quality of care for patients with TB and reduce the risk of nosocomial transmission of TB.

Since the work of John Snow, scientists and medical professionals have understood that individuals develop cholera by means of consuming contaminated water. Despite the knowledge of cholera's route of infection, many countries have experienced and still experience endemic cholera. Cholera is caused by the Vibrio cholerae (V. cholerae) bacterium and presents with acute diarrhea and vomiting. If untreated, infected individuals may die due to dehydration. Cholera is a disease that most commonly affects countries with poor infrastructure and water sanitation. Despite efforts to control cholera in such countries, the disease persists. One such example is Haiti which has been experiencing a cholera outbreak since 2010. While there has been much research in the field of microbiology to understand V. cholerae, there has been comparably less research in the field of mathematical biology to understand the dynamics of V. cholerae in the environment. A mathematical model of V. cholerae incorporating a phage population is coupled with a SIRS disease model to examine the impact of vibrio and phage interaction. It is shown that there might exist two endemic equilibria, besides the disease free equilibrium: one in which phage persist in the environment and one in which the phage fail to persist. Existence and stability of these equilibria are established. Disease control strategies based on vibrio and phage interactions are discussed.

Vibrio vulnificus, an emergent human pathogen, causes septicemia with a mortality rate over 50%. Additionally, symptom onset occurs rapidly, with the incubation time for ingestion cases being around 26 hours. This, combined with the severity of symptoms has led to V. vulnificus being considered the deadliest seafood-associated pathogen, claiming responsibility for 95% of seafood-related deaths. Currently, the molecular mechanisms through which some strains of this bacteria emerge to become pathogens are unknown. The main focus of this study is to expand upon the base of knowledge surrounding this question through comparing virulence phenotypes in environmentally collected strains of V. vulnificus. Specifically, this study will evaluate the pathogenic potential of environmental isolates collected from water and oyster sources in Lee County, Florida, in lieu of the outbreak that occurred in October 2022. To test this, a variety of assays were performed. First, a phylogenetic tree was built to establish the relationships between strains. Next, to study in vitro responses, serum resistance assays and sialic acid growth curves were performed. Then, to further classify the pathogenic potential of these environmental strains, they were tested against THP-1 monocytes differentiated into macrophages for their ability to resist phagocytosis and induce apoptosis. This study found differential responses amongst the environmental isolates, with some exhibiting significant pathogenic potential and others being sensitive to all tested assays. Understanding which strains emerge as pathogens will help determine the prevalence of key virulence factors within natural populations of bacteria and provide critical data on the phenotypic outcomes of differing genotypes.

The hypotheses challenged in this project were (1) people are the source for meticillin-resistant Staphylococcus aureus (MRSA) in pets, (2) risk factors for MRSA infection and carriage mirror those described in humans, (3) S. aureus continues to evolve on animals, (4) MRSA is carried by a substantial number of companion animals and (5) pets can be a reservoir for MRSA. Risk factors for MRSA pet infection were determined in a UK-wide case-control study enrolling dogs and cats with S. aureus infection (138 MRSA; 122 MSSA), their veterinary staff and owners. MRSA were typed and 12 paired human-animal isolates were compared by whole genome microarrays. MRSA carriage was examined in selected populations of dogs, cats and horses (n=1692) in the Greater London area and dog-to-dog transmission of MRSA was examined during an outbreak in a rescue kennel. Key findings were (a) an occupational risk for MRSA carriage in UK first opinion veterinary staff (9%), (b) antimicrobial therapy, surgery and admission to veterinary hospitals as major risk factors for pet MRSA infection; (c) human healthcareassociated lineages predominated amongst animals but (d) host-specific variation occurred within the same lineage, (e) MRSA carriage in the studied animal populations was low «1.5%), (f) "classical" risk factors were not involved in animal carriage but co-carriage of other staphylococci was protective against MRSA, (g) decolonisation occurred naturally and (h) dog-to-dog transmission was not observed. MRSA ST398 was identified from one horse, the first isolation from an animal in the UK. These findings support the concept that pets acquire MRSA primarily from people but are unlikely natural hosts for healthcare-associated MRSA. Therefore, rigorous personal and environmental hygiene combined with conscientious use of antimicrobial agents should be highly effective in veterinary clinics. Bacterial interference should be further investigated as a preventative measure. Vigilance is warranted as new strains may evolve on and spread between companion animals.

Fever in infants younger than 2 months of age causes a significant number of emergency department visits and is particularly worrisome because of the potential for serious infection. Management of febrile infants is problematic because clinical observation is not a reliable indicator of serious bacterial illness (SBI), such as bacteremia, meningitis, and urinary tract infection (UTI). Numerous investigators have proposed methods of screening laboratory tests to ascertain the risk of SBI in febrile infants. These screening tests could potentially avoid the invasive and costly sepsis work-up, which usually includes complete blood count (CBC), blood culture, urinalysis, urine culture, and lumbar puncture. We conducted a prospective, cross-sectional study that examined the prevalence of rhinovirus (RV) and coronavirus (CoV), which are two of the most common causes of upper respiratory infections in the first year of life, and human metapneumovirus (hMPV), which is a common cause of bronchiolitis, in infants younger than 2 months of age. This study also examined whether febrile infants with RV were more or less likely to also have a SBI than infants without a viral respiratory infection. Methodology: Fever was defined as rectal temperatures greater than 37.9C or a historical fever greater than 100.3F. Nasal swabs were tested with reverse transcriptase polymerase chain reaction (rt-PCR) techniques for rhinoviruses (RV), human metapneumovirus (hMPV) and coronaviruses (CoV). Nasal samples were also tested for RSV, influenza A and B, parainfluenza types 1, 2 and 3, and adenovirus via direct fluorescent antibody (DFA). Conclusion: Rhinovirus (RV) was the most commonly detected respiratory viral pathogen in our cohort (14% out of 98 total enrolled patients). Coronovirus (CoV) and human metapneumovirus (hMPV) were both detected but in only one patient (1%) each. RV occurred predominantly in the summer (79%). This cohort of patients showed no difference between the incidence of serious bacterial illness (SBI) with and without RV infection (p=0.84).

Pseudomonas Aeruginosa is a common gram-negative bacterium present in the environment. It causes severe infections in immunosuppressed patients. Cystic fibrosis patients are especially at risk of being infected with Pseudomonas Aeruginosa. Ongoing studies are preformed to find alternative therapies to antibiotics, due to increased resistance. One new treatment is intake of specific IgY antibodies against Pseudomonas Aeruginosa as an oral therapy. The problem today is that IgY solutions must be kept frozen until consumed.  In this study we examined the possibility to freeze-dry specific IgY antibodies without losing any activity or specificity of the antibodies. This would be more convenient of patients, as well as it makes transportation and storage easier.  The methods used were ELISA for control of activity, western blot analysis and SDS-PAGE gel for control of specificity. Three different batches of the IgY anti-Pseudomonas Aeruginosa solution were tested. The results showed that no loss in activity occurred that would affect clinical outcome or change of specificity in the antibodies after freeze-drying appears. This indicates that it is possible to replace the liquid antibody to a freeze-dried powder.

The LD50 of Vibrio parahaemolyticus ATCC 17803 for 13- to 18-g male mice, strain ICR, as determined by the 50% endpoint method, was found to be an estimated 7 x 107 CFU, when administered intraperitoneally in 0.5 ml of 24-h broth culture, O. D. 0.5 at 650 nm, diluted to 10-0.72. The elicitation of protective antibody by this bacterium in male New Zealand White rabbits was demonstrated by testing control, baseline, and hyperimmune rabbit sera for their protective effect against 2 LD50 of the bacterium administered intraperitoneally in 13- to 18-g male mice, strain ICR. A comparison of these sera showed that there was a highly significant difference, at the 0.01 level, between the protection conferred by the hyperimmune sera and the protection conferred by the baseline or control area. Significant protection was demonstrated by hperimmune sera at dilutions as high as 1/32. Comparison of results of in vitro tests for preciptins and agglutinins in hyperimmune rabbit sera with results of in vivo tests for protective effect of hyperimmune rabbit sera led to a tentative conclusion that this passive protection afforded by the hyperimmune rabbit sera is probably conferred more by precipitins than by agglutinins.

Staphylococcus aureus is a Gram positive potentially pathogenic bacterium which has a propensity to gather resistance determinants. Mupirocin is a novel topical antibiotic active against many Gram positive species, including staphylococci and effective in the treatment and prevention of staphylococcal infections. Mupirocin acts by competitively inhibiting the charging of isoleucyl tRNA-synthetase (IRS) with isoleucine. Resistance has been observed in Staphylococcus aureus and coagulase negative staphylococci. Intermediate-level resistance (MIC >8μg ml^-1 >512μg ml^-1) is thought to be due to spontaneous mutations in the native IRS. High-level resistance (>512μg ml^-1) is conferred by a second IRS protein, encoded by mupA which has a much lower affinity for mupirocin than isoleucine. The mupirocin resistance gene (mupA) is usually found on a 4.05kb EcoRI fragment of plasmids of otherwise varied EcoRI restriction pattern which are easily transferred between strains by filter mating. Prior to the onset of these studies, mupirocin resistance had not been found linked to another resistance determinant. Initial investigations intended to identify mechanisms of gene flux resident on mupA plasmids revealed a family of related mupA plasmids, the p3356 family which includes three plasmid types: p3356, p3356D and p3358. p3356 contains a single copy mupA flanked by direct repeats of the staphylococcal insertion sequence IS257. p3356D is identical to p3356 except for the duplication of a "mupA-IS257" cassette in tandem repeat. p3358 is related to p3356D by the insertion of a pT181-like plasmid (tetracycline resistant) accompanied by the duplication of an IS257 in direct repeat to flank the inserted pT181; thus p3358 is the first documented example of linked resistance between mupirocin and another resistance determinant, namely tetracycline. IS257 has been implicated as the recombinogenic site in the gene duplication event involved in the evolution of p3356D from p3356. IS257 co-integrative transposition has been demonstrated to allow the co-integration of pOX7 with p3356 to generate a p3358-type plasmid in which pT181 is replaced by pOX7. Therefore, it is concluded that IS257 transposition and recombination is a mechanism by which staphylococcal replicons can evolve to form multiply resistant replicons.