Management and outcomes of anorectal infection in the cancer patient

Background. The objective of this retrospective cohort study is to examine the presentation and outcomes for a contemporary series of cancer patients with anorectal infection. In addition, we seek to identify factors which are associated with surgical intervention. ^ Methods. The study cohort was identified from ICD-9 codes for diagnosis of infection of the anal and rectal region and patients who underwent a surgical oncology consultation between 1/2000 and 12/2006. Clinical presentation, treatment rendered, and outcomes were retrospectively recorded. ^ Results. Of the 100 patients evaluated by the surgical oncology service for anorectal infection, 42 were treated non-operatively and 58 underwent surgical intervention. Factors associated with surgical intervention based on logistic multivariable analysis included the diagnosis of an abscess (odds ratio [OR] 10.5; 95% confidence interval [CI] 2.9-38.5) and the documentation of erythema on physical examination (OR 3.1; 95% CI 1.1-8.4). Thrombocytopenia (platelets < 50,000) was associated with non-operative management (OR 0.3; 95% CI 0.1-0.7). Incision and drainage was the most common surgical procedure (79%) while a wide debridement for a necrotizing soft tissue infection was required in 2 patients. Infection-specific 90-day mortality was only 1% (N=1). However, the median overall survival for the entire cohort was only 14.4 months (95% CI 7.9-19.5). ^ Conclusions. Non-operative management is a reasonable treatment option for anorectal infection in patients with cancer. Identification of an abscess, erythema on physical exam, and thrombocytopenia were associated with management strategy. Although rare, necrotizing soft tissue infections are associated with significant mortality. ^

Characterization of Staphylococcus aureus adhesins important for respiratory tract infection

Staphylococcus aureus is a leading cause of lower respiratory tract infections in both adult and pediatric populations. In the past two decades, reports have described emergent incidence of severe necrotizing pneumonia in previously healthy individuals, frequently caused by antibiotic resistant strains. Additionally, S. aureus remains the most common cause of ventilator-associated pneumonia, contributing morbidity and mortality in intensive care units. As treatment of infection is made more difficult by the resistance to multiple antibiotics including vancomycin, there is a pressing need for novel strategies to prevent and treat S. aureus infections. Targeting essential mechanisms that promote infection such as adhesion, colonization, invasion, evasion of immune system and signaling may lead to inhibition of pathogenic surge. Staphylococcal adhesins of the MSCRAMM family (microbial surface components recognizing adherent matrix molecules) represent viable targets for such investigations. Understanding the molecular mechanism of binding is the first step toward the development of such therapies. Analysis of bacterial strains isolated from patients with staphylococcal pneumonia show increased expression of protein A, SdrD, SdrC and ClfB, cell surface proteins members of the MSCRAMM family. In this study the interaction of these MSCRAMMs with candidate ligands has been examined. We found that SdrD mediates S. aureus adherence to the lung epithelial cell line A549. Consistently, bacteria expressing SdrD have increased persistence in the lungs of infected mice after bronchoalveolar lavage in comparison with bacteria lacking this protein. Inhibition studies revealed that bacterial attachment can be abolished using neutralizing antibodies against SdrD. Using phage display, neurexin β isoforms were identified as SdrC binding partners. Previous reports postulated that MSCRAMMS bind their ligands by a 'dock, lock and latch' mechanism of interaction. Our data suggested that ClfB, an MSCRAMM responsible for nasal colonization, binds cytokeratin 10 by a 'dock and lock' variant of this model, in which the 'latching' event is not necessary. In summary, we have characterized aspects of molecular interaction between several MSCRAMMS and host components. We hope that continued delineation of these interactions will lead to identification of novel therapeutic targets or preventive strategies against S. aureus infections. ^

Host risk factors for rifamycin-resistant clostridium difficile infection: A case control study

Objective. To evaluate the host risk factors associated with rifamycin-resistant Clostridium difficile (C. diff) infection in hospitalized patients compared to rifamycin-susceptible C.diff infection.^ Background. C. diff is the most common definable cause of nosocomial diarrhea affecting elderly hospitalized patients taking antibiotics for prolonged durations. The epidemiology of Clostridium difficile associated disease is now changing with the reports of a new hypervirulent strain causing hospital outbreaks. This new strain is associated with increased disease severity and mortality. The conventional therapy for C. diff includes metronidazole and vancomycin but high recurrence rates and treatment failures are now becoming a major concern. Rifamycin antibiotics are being developed as a new therapeutic option to treat C. diff infection after their efficacy was established in a few in vivo and in vitro studies. There are some recent studies that report an association between the hypervirulent strain and emerging rifamycin resistance. These findings assess the need for clinical studies to better understand the efficacy of rifamycin drugs against C. diff.^ Methods. This is a hospital-based, matched case-control study using de-identified data drawn from two prospective cohort studies involving C. diff patients at St Luke's Hospital. The C. diff isolates from these patients are screened for rifamycin resistance using agar dilution methods for minimum inhibitory concentrations (MIC) as part of Dr Zhi-Dong Jiang's study. Twenty-four rifamycin-rifamycin resistant C. diff cases were identified and matched with one rifamycin susceptible C. diff control on the basis of ± 10 years of age and hospitalization 30 days before or after the case. De-identified data for the 48 subjects was obtained from Dr Kevin Garey's clinical study at St Luke's Hospital enrolling C. diff patients. It was reviewed to gather information about host risk factors, outcome variables and relevant clinical characteristic.^ Results. Medical diagnosis at the time of admission (p = 0.0281) and history of chemotherapy (p = 0.022) were identified as a significant risk factor while hospital stay ranging from 1 week to 1 month and artificial feeding were identified as an important outcome variable (p = 0.072 and p = 0.081 respectively). Horn's Index assessing the severity of underlying illness and duration of antibiotics for cases and controls showed no significant difference.^ Conclusion. The study was a small project designed to identify host risk factors and understand the clinical implications of rifamycin-resistance. The study was underpowered and a larger sample size is needed to validate the results.^

Clinical and economic outcomes of serious postoperative infections following resection of common respiratory and gastrointestinal solid tumors

Unlike infections occurring during periods of chemotherapy-induced neutropenia, postoperative infections in patients with solid malignancy remain largely understudied. The purpose of this population-based study was to evaluate the clinical and economic burden, as well as the relationship of hospital surgical volume and outcomes associated with serious postoperative infection (SPI) – i.e., bacteremia/sepsis, pneumonia, and wound infection – following resection of common solid tumors.^ From the Texas Discharge Data Research File, we identified all Texas residents who underwent resection of cancer of the lung, esophagus, stomach, pancreas, colon, or rectum between 2002 and 2006. From their billing records, we identified ICD-9 codes indicating SPI and also subsequent SPI-related readmissions occurring within 30 days of surgery. Random-effects logistic regression was used to calculate the impact of SPI on mortality, as well as the association between surgical volume and SPI, adjusting for case-mix, hospital characteristics, and clustering of multiple surgical admissions within the same patient and patients within the same hospital. Excess bed days and costs were calculated by subtracting values for patients without infections from those with infections computed using multilevel mixed-effects generalized linear model by fitting a gamma distribution to the data using log link.^ Serious postoperative infection occurred following 9.4% of the 37,582 eligible tumor resections and was independently associated with an 11-fold increase in the odds of in-hospital mortality (95% Confidence Interval [95% CI], 6.7-18.5, P < 0.001). Patients with SPI required 6.3 additional hospital days (95% CI, 6.1 - 6.5) at an incremental cost of $16,396 (95% CI, $15,927–$16,875). There was a significant trend toward lower overall rates of SPI with higher surgical volume (P=0.037). ^ Due to the substantial morbidity, mortality, and excess costs associated with SPI following solid tumor resections and given that, under current reimbursement practices, most of this heavy burden is borne by acute care providers, it is imperative for hospitals to identify more effective prophylactic measures, so that these potentially preventable infections and their associated expenditures can be averted. Additional volume-outcomes research is also needed to identify infection prevention processes that can be transferred from higher- to lower-volume providers.^

Prevalence of gastro esophageal reflux disease following the Montreal Consensus and its association with Helicobacter pylori infection and obesity in a random sample of adults of Ciudad Juarez, Mexico, 2004.

Gastroesophageal reflux disease is a common condition affecting 25 to 40% of the population and causes significant morbidity in the U.S., accounting for at least 9 million office visits to physicians with estimated annual costs of $10 billion. Previous research has not clearly established whether infection with Helicobacter pylori, a known cause of peptic ulcer, atrophic gastritis and non cardia adenocarcinoma of the stomach, is associated with gastroesophageal reflux disease. This study is a secondary analysis of data collected in a cross-sectional study of a random sample of adult residents of Ciudad Juarez, Mexico, that was conducted in 2004 (Prevalence and Determinants of Chronic Atrophic Gastritis Study or CAG study, Dr. Victor M. Cardenas, Principal Investigator). In this study, the presence of gastroesophageal reflux disease was based on responses to the previously validated Spanish Language Dyspepsia Questionnaire. Responses to this questionnaire indicating the presence of gastroesophageal reflux symptoms and disease were compared with the presence of H. pylori infection as measured by culture, histology and rapid urease test, and with findings of upper endoscopy (i.e., hiatus hernia and erosive and atrophic esophagitis). The prevalence ratio was calculated using bivariate, stratified and multivariate negative binomial logistic regression analyses in order to assess the relation between active H. pylori infection and the prevalence of gastroesophageal reflux typical syndrome and disease, while controlling for known risk factors of gastroesophageal reflux disease such as obesity. In a random sample of 174 adults 48 (27.6%) of the study participants had typical reflux syndrome and only 5% (or 9/174) had gastroesophageal reflux disease per se according to the Montreal consensus, which defines reflux syndromes and disease based on whether the symptoms are perceived as troublesome by the subject. There was no association between H. pylori infection and typical reflux syndrome or gastroesophageal reflux disease. However, we found that in this Northern Mexican population, there was a moderate association (Prevalence Ratio=2.5; 95% CI=1.3, 4.7) between obesity (≥30 kg/m2) and typical reflux syndrome. Management and prevention of obesity will significantly curb the growing numbers of persons affected by gastroesophageal reflux symptoms and disease in Northern Mexico. ^

The relationship between enterotoxigenic {\it Escherichia coli\/} infection and environmental risk factors in Bilbeis, Egypt, 1981--1983

Diarrheal disease associated with enterotoxigenic Escherichia coli (ETEC) infection is one of the major public health problems in many developing countries, especially in infants and young children. Because tests suitable for field laboratories have been developed only relatively recently, the literature on the environmental risk factors associated with ETEC is not as complete as for many other pathogens or for diarrhea of unspecified etiology.^ Data from a diarrheal disease surveillance project in rural Egypt in which stool samples were tested for a variety of pathogens, and in which an environmental questionnaire was completed for the same study households, provided an opportunity to test for an association between ETEC and various risk factors present in those households. ETEC laboratory-positive specimens were compared with ETEC laboratory-negative specimens for both symptomatic and asymptomatic children less than three years of age at the individual and household level using a case-comparison design.^ Individual children more likely to have LT infection were those who lived in HHs that had cooked food stored for subsequent consumption at the time of the visit, where caretakers used water but not soap to clean an infant after a diarrheal stool, and that had an indoor, private water source. LT was more common in HHs where the caretaker did not clean an infant with soap after a diarrheal stool, and where a sleeping infant was not covered with a net. At both the individual and HH level, LT was significantly associated with good water supply in terms of quantity and storage.^ ST was isolated more frequently at the individual level where a sleeping infant was covered with a net, where large animals were kept in or around the house, where water was always available and was not potable, and where the water container was not covered. At the HH level, the absence of a toilet or latrine and the indiscriminate disposal of animal waste decreased risk. Using animal feces for fertilizer, the presence of large animals, and poor water quality were associated with ST at both the individual and HH level.^ These findings are mostly consistent with those of other studies, and/or are biologically plausible, with the obvious exception of those from this study where poorer water supplies are associated with less infection, at least in the case of LT. More direct observation of how animal ownership and feces disposal relates to different types of water supply and usage might clarify mechanisms through which some ETEC infection could be prevented in similar settings. ^

Effects of breastfeeding and naturally acquired immunity on infection with {\it Giardia lamblia}: A study in a cohort of Mexican infants

Giardia lamblia is one of the most common causes of gastrointestinal tract infection among young children worldwide. Yet host protection against this parasite and the effect of infection with Giardia on infant growth are poorly understood. It was hypothesized that among young children, protection against infection with Giardia is afforded by breastfeeding and previous infection with the parasite and further, that infection with Giardia decreases growth velocity. From 4/88 to 4/90, 197 infants in a poor area of Mexico City were followed from 0 to 18 months of age, with stool specimens, symptoms and feeding status data collected weekly. A total of 6,031 stool specimens were tested for Giardia antigen by enzyme-linked immunosorbent assay. There were 1.0 Giardia infections per child-year; 25% were symptomatic and 54% lasted more than 1 month; 94 infants had 1, and 33 had 2 or more infections. Breastfeeding status was coded and analyzed for each child-week of follow up. 91% of study infants were breastfed from birth, 57% at 6 months and 38% at 12 months of age. Rate ratios for non-breastfeeding adjusted for confounding factors were calculated from stratified analyses and the Cox proportional hazards model. Not breastfeeding was a significant risk factor for first infection with Giardia vs. any breastfeeding (adjusted RR = 1.8; 1.1, 2.8) at all ages; a dose response was demonstrated by degree of breastfeeding. The adjusted rate ratio for non-breastfeeding vs. partial breastfeeding was 1.6 (1.03, 2.6) and for non-breastfeeding vs. complete breastfeeding was 4.7 (1.4, 15.9). Among Giardia infected infants, breastfeeding did not protect against diarrheal symptoms or shorten the duration of carriage. First and repeat infections with Giardia did not differ in duration or the percent symptomatic. The analysis of growth and Giardia infection was inconclusive but suggested that a history of Giardia infection might be associated with decreased weight velocity, while an immediate chronic infection might be associated with increased weight velocity. In summary, these data indicate that breastfeeding protects infants against infection with Giardia; provide no evidence of protection against repeat infections resulting from a prior infection and suggest but do not establish that a history of Giardia infection might be associated with decreased growth in young children. ^

Survey analysis on dental infection control & occupational safety from India---1999 & 2010

The objective was to study knowledge, attitudes, practice (KAP) and needs regarding infection control measures using two cross-sectional surveys from 1999 and 2010 conducted in India. Both data collection instruments had only about 35 comparable variables in common. In 1999, there were 456 respondents (dentists) who completed a self-administered survey instrument compared to 272 respondents in 2010. Both the 1999 and 2010 samples were mutually independent with no overlap, had regional differences, and therefore, were not completely comparable for changes in KAP over time. While almost all respondents from both surveys felt that education in dental safety was needed and wanted mandatory dental safety curriculum in dental schools, severe inadequacies in dental safety knowledge, protection against immunizable diseases, and practice of universal precaution were noted. Data from the study demonstrated that there is a substantial opportunity to improve the knowledge, attitude and practice of dental infection control and occupational safety in India. Few respondents (27%) reported that the infectious disease status of a patient is always known and a significant number reported that they had the right to refuse care for patients of known infectious disease status. This indicates that Stigma in treating HIV/AIDS patients remains a concern, which in turn suggests that a stronger focus on educating dentists about dental safety and on stigma and infectious disease is needed. Information obtained from this study could be utilized for developing policies oriented towards increasing dental safety educational efforts, in both dental schools as curriculum, and for practicing dentists through professional updates or continuing dental education.^

Seasonality of respiratory syncytial virus infection in Texas

Respiratory syncytial virus (RSV) is a common cause of respiratory infection in infants and children that can result in bronchiolitis or pneumonia. Each year in the United States, it causes up to 400 deaths and 125,000 hospitalizations among children less than one year of age. RSV is transmitted by direct or close contact with contaminated secretions, which may involve droplets and fomites. Monthly administration of a monoclonal RSV antibody, palivizumab (Synagis™, MedImmune, Gaithersburg, MD), in premature infants, infants with chronic lung disease, or congenital heart disease has been shown to significantly reduce the risk of severe RSV infection. The Centers for Disease Control and Prevention's (CDC) National Respiratory and Enteric Virus Surveillance System (NREVSS) is a laboratory based passive reporting system that collects state, regional, and national RSV data. The CDC defines the RSV season onset as “the first of 2 consecutive weeks during which the mean percentage of specimens testing positive for RSV antigen is 10%.” RSV season offset is defined as the last of 2 consecutive weeks during which the percentage of positive specimens is less than or equal to 10%. Annual RSV epidemics generally occur during the winter and early spring months, but the RSV season is known to vary by national regions. Precise delineation of the RSV epidemiology by region could maximize protection from RSV and minimize the cost of RSV immune prophylaxis. ^ The purpose of this thesis is to define the RSV season in Texas over time; compare the RSV season of the state of Texas and its regions with the national norms; and to compare RSV seasonality between the various regions in Texas. ^ This study was a retrospective analysis of data reported to NREVSS to evaluate potential disparities in the onset weeks, offset weeks, and duration of the annual RSV season in Texas. Data were collected from 70 reporting sites, and includes information from the 2004–2005 to 2009–2010 RSV seasons. ^ The observed median onset (week 44) and offset week (week 8) for the Texas were consistent with national estimates for the South. Regional estimates and statistical analysis suggested that the RSV season in Texas would be better represented by regions. Regional seasonal comparisons revealed considerable variation in season offset and duration between many of the geographic regions within Texas. This trend should be studied further.^

Prevalence and determinants of hepatitis B co-infection among a United States Veterans Administration cohort with hepatitis C

Background and aim. Hepatitis B virus (HBV) and hepatitis C virus (HCV) co-infection is associated with increased risk of cirrhosis, decompensation, hepatocellular carcinoma, and death. Yet, there is sparse epidemiologic data on co-infection in the United States. Therefore, the aim of this study was to determine the prevalence and determinants of HBV co-infection in a large United States population of HCV patients. ^ Methods. The National Veterans Affairs HCV Clinical Case Registry was used to identify patients tested for HCV during 1997–2005. HCV exposure was defined as two positive HCV tests (antibody, RNA or genotype) or one positive test combined with an ICD-9 code for HCV. HCV infection was defined as only a positive HCV RNA or genotype. HBV exposure was defined as a positive test for hepatitis B core antibodies, hepatitis B surface antigen, HBV DNA, hepatitis Be antigen, or hepatitis Be antibody. HBV infection was defined as only a positive test for hepatitis B surface antigen, HBV DNA, or hepatitis Be antigen within one year before or after the HCV index date. The prevalence of exposure to HBV in patients with HCV exposure and the prevalence of HBV infection in patients with HCV infection were determined. Multivariable logistic regression was used to identify demographic and clinical determinants of co-infection. ^ Results. Among 168,239 patients with HCV exposure, 58,415 patients had HBV exposure for a prevalence of 34.7% (95% CI 34.5–35.0). Among 102,971 patients with HCV infection, 1,431 patients had HBV co-infection for a prevalence of 1.4% (95% CI 1.3–1.5). The independent determinants for an increased risk of HBV co-infection were male sex, positive HIV status, a history of hemophilia, sickle cell anemia or thalassemia, history of blood transfusion, cocaine and other drug use. Age >50 years and Hispanic ethnicity were associated with a decreased risk of HBV co-infection. ^ Conclusions. This is the largest cohort study in the United States on the prevalence of HBV co-infection. Among veterans with HCV, exposure to HBV is common (∼35%), but HBV co-infection is relatively low (1.4%). There is an increased risk of co-infection with younger age, male sex, HIV, and drug use, with decreased risk in Hispanics.^

Economic evaluation of latent tuberculosis infection screening among health care workers in Houston

Since interferon-gamma release assays (IGRAs) were introduced in the 2000's, tuberculin skin testing (TST) and IGRAs have been used in various latent tuberculosis infection (LTBI) screening settings. IGRAs are laboratory-based tests and are considered not to be affected by previous Bacille de Calmette et Guérin (BCG) vaccination; however, they are more costly when compared directly with TST, which does not require specimen processing in a laboratory. This study aimed to examine TST and two types of IGRAs, QuantiFERON-TB Gold in Tube (QFT-GIT) and T-SPOT. TB (TSPOT), from an economic viewpoint. Firstly, a systematic literature review was conducted to identify cost related analyses of LTBI screening. Secondly, specific cost information detailing each test's items and labor was collected from an LTBI screening program of health care workers in Houston, and the cost of each test was computed. Thirdly, using the computed cost estimate of each test, cost-effectiveness analyses were conducted to compare TST and IGRAs.^ A literature search showed that a limited number of studies have been conducted, but the IGRA's economic advantages were common among studies. Cost analyses showed that IGRAs were much more costly than TST. The results were consistent with previous studies. In cost-effectiveness analyses, where test cost and consequential TB-related cost were considered, IGRAs showed variable advantages over TST depending on the targeted population. When only non BCG-vaccinated people were considered, TST was the least costly option among the three tests. On the other hand, when only BCG-vaccinated people were considered, IGRAs were less costly options. These results were mostly consistent even with varying assumption parameters.^ IGRAs can be more costly than TST, but their economic disadvantages are alleviated when the target population was BCG-vaccinated. Based on current knowledge, IGRAs may be recommended in a population where the BCG history is mixed. Additional studies are needed to better understand IGRA's reliability among low-incidence and low-risk populations in which background TB prevalence is low.^

Clostridium difficile infection (CDI): Clinical outcomes associated with concomitant non-CDI antibiotic use

This research examined the relationship between concomitant non-CDI antibiotic use and complications arising due to Clostridium difficile infection. To observe the hypothesized association, 160 total CDI patients between the ages of 50-90 were selected, 80 exposed to concomitant antibiotics and 80 unexposed. Samples were matched based upon their age and Horn's index, a severity score for underlying illness. Patients were de-identified by a third party, and analyzed retrospectively for differences between the two groups. In addition, patients exposed to broad spectrum antibiotics at the time of CDI treatment were further studied to demonstrate whether antibiotics had any effect on CDI complications. Between the two groups, the outcomes of interest (recurrent CDI, refractory CDI, mortality, ICU stay, and length of hospitalization) were not associated with concomitant antibiotic use at the time of CDI therapy. However, within the exposed population, certain classes of antibiotics such as cephalosporin, antifungals, and tetracyclines were more common in patients compared to other types of therapy. In addition, days of therapy provided evidence that sustained use of antibiotics affected CDI (p = 0.08), although a more robust sample size and additional study would be needed. Finally, refractory CDI was found to be potentially overestimated within the exposed population due to the possibility of antibiotic-associated diarrhea.^

The common nodABC genes of Rhizobium meliloti are host-range determinants

Symbiotic bacteria of the genus Rhizobium synthesize lipo-chitooligosaccharides, called Nod factors (NFs), which act as morphogenic signal molecules on legume hosts. The common nodABC genes, present in all Rhizobium species, are required for the synthesis of the core structure of NFs. NodC is an N-acetylglucosaminyltransferase, and NodB is a chitooligosaccharide deacetylase; NodA is involved in N-acylation of the aminosugar backbone. Specific nod genes are involved in diverse NF substitutions that confer plant specificity. We transferred to R. tropici, a broad host-range tropical symbiont, the ability to nodulate alfalfa, by introducing nod genes of R. meliloti. In addition to the specific nodL and nodFE genes, the common nodABC genes of R. meliloti were required for infection and nodulation of alfalfa. Purified NFs of the R. tropici hybrid strain, which contained chitin tetramers and were partly N-acylated with unsaturated C16 fatty acids, were able to elicit nodule formation on alfalfa. Inactivation of the R. meliloti nodABC genes suppressed the ability of the NFs to nodulate alfalfa. Studies of NFs from nodA, nodB, nodC, and nodI mutants indicate that (i) NodA of R. meliloti, in contrast to NodA of R. tropici, is able to transfer unsaturated C16 fatty acids onto the chitin backbone and (ii) NodC of R. meliloti specifies the synthesis of chitin tetramers. These results show that allelic variation of the common nodABC genes is a genetic mechanism that plays an important role in signaling variation and in the control of host range.

The GroES homolog of Helicobacter pylori confers protective immunity against mucosal infection in mice.

Helicobacter pylori is an important etiologic agent of gastroduodenal disease. In common with other organisms, H. pylori bacteria express heat shock proteins that share homologies with the GroES-GroEL class of proteins from Escherichia coli. We have assessed the heat shock proteins of H. pylori as potential protective antigens in a murine model of gastric Helicobacter infection. Orogastric immunization of mice with recombinant H. pylori GroES- and GroEL-like proteins protected 80% (n = 20) and 70% (n = 10) of animals, respectively, from a challenge dose of 10(4) Helicobacter felis bacteria (compared to control mice, P = 0.0042 and P = 0.0904, respectively). All mice (n = 19) that were immunized with a dual antigen preparation, consisting of H. pylori GroES-like protein and the B subunit of H. pylori urease, were protected against infection. This represented a level of protection equivalent to that provided by a sonicated Helicobacter extract (P = 0.955). Antibodies directed against the recombinant H. pylori antigens were predominantly of the IgG1 class, suggesting that a type 2 T-helper cell response was involved in protection. This work reports a protein belonging to the GroES class of heat shock proteins that was shown to induce protective immunity. In conclusion, GroES-like and urease B-subunit proteins have been identified as potential components of a future H. pylori subunit vaccine.

Multifaceted roles of the lysosome in the establishment and expansion of tuberculous infection

Thesis (Ph.D.)--University of Washington, 2016-04