David B. Banach

Hemagglutinin stalk antibodies elicited by the 2009 pandemic influenza virus as a mechanism for the extinction of seasonal H1N1 viruses

After the emergence of pandemic influenza viruses in 1957, 1968, and 2009, existing seasonal viruses were observed to be replaced in the human population by the novel pandemic strains. We have previously hypothesized that the replacement of seasonal strains was mediated, in part, by a population-scale boost in antibodies specific for conserved regions of the hemagglutinin stalk and the viral neuraminidase. Numerous recent studies have shown the role of stalk-specific antibodies in neutralization of influenza viruses; the finding that stalk antibodies can effectively neutralize virus alters the existing dogma that influenza virus neutralization is mediated solely by antibodies that react with the globular head of the viral hemagglutinin. The present study explores the possibility that stalk-specific antibodies were boosted by infection with the 2009 H1N1 pandemic virus and that those antibodies could have contributed to the disappearance of existing seasonal H1N1 influenza virus strains. To study stalk-specific antibodies, we have developed chimeric hemagglutinin constructs that enable the measurement of antibodies that bind the hemagglutinin protein and neutralize virus but do not have hemagglutination inhibition activity. Using these chimeric hemagglutinin reagents, we show that infection with the 2009 pandemic H1N1 virus elicited a boost in titer of virus-neutralizing antibodies directed against the hemagglutinin stalk. In addition, we describe assays that can be used to measure influenza virus-neutralizing antibodies that are not detected in the traditional hemagglutination inhibition assay.

Prevalence and Risk Factors for Acquisition of Carbapenem-Resistant Enterobacteriaceae in the Setting of Endemicity

OBJECTIVE To describe the epidemiology of carbapenem-resistant Enterobacteriaceae (CRE) carriage and acquisition among hospitalized patients in an area of CRE endemicity. DESIGN Cohort study with a nested case-control study. SETTING Two acute care, academic hospitals in New York City. PARTICIPANTS All patients admitted to 7 study units, including intensive care, medical-surgical, and acute rehabilitation units. METHOD Perianal samples were collected from patients at admission and weekly thereafter to detect asymptomatic gastrointestinal carriage of CRE. A nested case-control study was performed to identify factors associated with CRE acquisition. Case patients were those who acquired CRE during a single hospitalization. Control subjects had no microbiologic evidence of CRE and at least 1 negative surveillance sample. Clinical data were abstracted from the medical record. RESULTS The prevalence of CRE in the study population was 5.4% (306 of 5,676 patients), and 104 patients met the case definition of acquisition during a single hospital stay. Mechanical ventilation (odds ratio [OR], 11.5), pulmonary disease (OR, 5.2), days of antibiotic therapy (OR, 1.04), and CRE colonization pressure (OR, 1.15) were independently associated with CRE acquisition. Pulsed-field gel electrophoresis analysis identified 87% of tested Klebsiella pneumoniae isolates as sharing related patterns (greater than 78% similarity), which suggests clonal transmission within and between the study hospitals. CONCLUSIONS Critical illness and underlying medical conditions, CRE colonization pressure, and antimicrobial exposure are important risk factors for CRE acquisition. Adherence to infection control practices and antimicrobial stewardship appear to be critical components of a CRE control program.

Localized Mucosal Response to Intranasal Live Attenuated Influenza Vaccine in Adults

BACKGROUND Influenza virus infection is a major public health burden worldwide. Available vaccines include the inactivated intramuscular trivalent vaccine and, more recently, an intranasal live attenuated influenza vaccine (LAIV). The measure of successful vaccination with the inactivated vaccine is a systemic rise in immunoglobulin G (IgG) level, but for the LAIV no such correlate has been established. METHODS Seventy-nine subjects were given the LAIV FluMist. Blood was collected prior to vaccination and 3 days and 30 days after vaccination. Nasal wash was collected 3 days and 30 days after vaccination. Responses were measured systemically and in mucosal secretions for cytokines, cell activation profiles, and antibody responses. RESULTS Only 9% of subjects who received LAIV seroconverted, while 33% of patients developed at least a 2-fold increase in influenza virus-specific immunoglobulin A (IgA) antibodies in nasal wash. LAIV induced a localized inflammation, as suggested by increased expression of interferon-response genes in mucosal RNA and increased granulocyte colony-stimulating factor (G-CSF) and IP-10 in nasal wash. Interestingly, patients who seroconverted had significantly lower serum levels of G-CSF before vaccination. CONCLUSIONS Protection by LAIV is likely provided through mucosal IgA and not by increases in systemic IgG. LAIV induces local inflammation. Seroconversion is achieved in a small fraction of subjects with a lower serum G-CSF level.

Public Health Implications of Rapid Hepatitis C Screening With an Oral Swab for Community-Based Organizations Serving High-Risk Populations

OBJECTIVES Between April and September of 2009 we evaluated the accuracy of the OraQuick HCV rapid antibody test and assessed its feasibility for use by community-based organizations (CBOs) serving populations at high risk for HCV in New York City. METHODS We compared the results of screening by OraQuick (oral swab) and enzyme immunoassay (EIA; blood draw). We performed ribonucleic acid polymerase chain reaction testing for discordant results. We also assessed research staff perceptions through a survey and focus group. RESULTS Overall, 97.5% of OraQuick and EIA results matched. Testing of discordant samples indicated that the rapid test was more likely than the EIA to provide a correct diagnosis. Research staff preferred the rapid test and identified challenges that would be overcome with its use. CBOs could benefit from increased testing capacity, and clients might benefit from more rapid access to education, counseling, and referrals. CONCLUSIONS OraQuicks accuracy is comparable to the EIA. The oral swab rapid test could help HCV screening programs reach individuals unaware of their status and expand testing into nonclinical settings such as mobile units.

Isolation Precautions for Visitors

Infection Control & Hospital Epidemiology / FirstView Article / April 2015, pp 1 12 DOI: 10.1017/ice.2015.67, Published online: 10 April 2015 Link to this article: http://journals.cambridge.org/abstract_S0899823X15000677 How to cite this article: L. Silvia Munoz-Price, David B. Banach, Gonzalo Bearman, Jane M. Gould, Surbhi Leekha, Daniel J. Morgan, Tara N. Palmore, Mark E. Rupp, David J. Weber and Timothy L. Wiemken Isolation Precautions for Visitors. Infection Control & Hospital Epidemiology, Available on CJO 2015 doi:10.1017/ice.2015.67 Request Permissions : Click here

Indeterminate QuantiFERON®-TB Gold results in a public health clinic setting.

SETTING Public chest clinics, New York City. OBJECTIVE To evaluate the association between patient characteristics and indeterminate QuantiFERON ® TB Gold (QFT-G) results and describe follow-up testing. DESIGN Retrospective cross-sectional multivariate logistic regression analyses of patients receiving QFT-G from October 2006 to June 2008. Analyses were performed separately depending on whether the indeterminate result was due to positive (low mitogen) or negative (high nil) control failure. RESULTS Of 28 864 individuals tested, 2058 (7%) tested positive, 26 284 (91%) negative, and 522 (2%) were indeterminate (low mitogen, n = 264; high nil, n = 258). Low mitogen results were more frequent among those aged < 10 years (OR(adj) 3.7, 95%CI 2.4-5.9), females (OR(adj) 1.4, 95%CI 1.1-1.8), Asians (OR(adj) 2.1, 95%CI 1.3-3.4) and the US-born (OR(adj) 1.9, 95%CI 1.4-2.6) and less frequent among Hispanics (OR(adj) 0.6, 95%CI 0.4-1.0). High nil results were more frequent among Hispanics (OR(adj) 1.7, 95%CI 1.0-2.8) and less frequent among the US-born (OR(adj) 0.6, 95%CI 0.5- 0.8). Among patients who received a repeat QFT-G (n = 137), 4% tested positive, 64% negative and 32% had a second indeterminate result, always of the same type. CONCLUSION Age, race/ethnicity and sex were associated with indeterminate QFT-G results. Most follow-up tests were negative, although a modest proportion were repeatedly indeterminate. Further studies evaluating the mechanisms of QFT-G indeterminate results are needed.

Factors Associated with Unprotected Exposure to 2009 H1N1 Influenza A among Healthcare Workers during the First Wave of the Pandemic

Protecting healthcare workers (HCWs) from occupational exposure to 2009 H1N1 influenza was a challenge. During the first wave of the pandemic, many HCWs reported that they had been exposed to 2009 H1N1 when they were not using respiratory personal protective equipment. Unprotected exposures tended to be more frequent among HCWs caring for patients with atypical clinical presentations.

Infection control precautions for visitors to healthcare facilities

Infection transmission in healthcare facilities is a growing concern. Visitation to healthcare facilities is very common, though the potential role of visitors in the transmission of infection is unknown. Although transmission-based precautions are generally used to prevent the spread of organisms in healthcare settings by healthcare staff, the applicability of these precautions to visitors is unclear. Decisions regarding whether to implement transmission-based precautions among visitors should take into account the organism of concern and means of transmission as well as factors pertaining to the visitor and the healthcare setting. The role of visitors as vectors for organism transmission in the healthcare setting and the potential benefits and adverse consequences of visitor adherence with transmission-based precautions are important areas for additional research.

Support for mandatory health care worker influenza vaccination among allied health professionals, technical staff, and medical students

Although policies mandating annual influenza vaccination among health care workers (HCWs) are recommended, little is known about which HCWs support mandatory vaccination. We surveyed non-physician, non-nursing HCWs to identify beliefs associated with supporting mandatory HCW vaccination. Although similarities were identified, some beliefs and concerns associated with supporting mandatory vaccination differed among HCW groups. Policy makers should understand these differences and address beliefs and concerns of all HCW groups when attempting to implement a mandatory influenza vaccination policy.

The clinical and molecular epidemiology of pre-transplant vancomycin-resistant enterococci colonization among liver transplant recipients.

Vancomycin‐resistant enterococci (VRE) infections cause significant morbidity in liver transplant recipients. The epidemiology and impact of pre‐transplant colonization with VRE among patients who undergo liver transplantation are poorly understood. We conducted an observational cohort study to identify risk factors and outcomes associated with pre‐transplant VRE colonization and described the molecular diversity among VRE strains colonizing patients who undergo liver transplantation. Perirectal VRE surveillance cultures were performed prior to transplantation. Repetitive sequence‐based polymerase chain reaction (rep‐PCR) testing was used to identify clonality among VRE isolates. Of 61 patients who underwent pre‐transplant VRE surveillance and subsequent liver transplantation, 27 (44%) were colonized with VRE. In multivariate analysis, pre‐transplant VRE colonization was associated with central venous catheterization (OR 9.4, 95% confidence interval [CI]= 1.3–70.2, p = 0.03) and rifaximin use (OR 15.4, 95% CI 1.5–159.7, p = 0.02). Pre‐transplant VRE colonization was associated with more hospital days post‐transplant (26.6 vs. 16.1 d, p = 0.04). Of VRE‐colonized patients analyzed with rep‐PCR, 68% were colonized with the same strain as another patient in the cohort. Active surveillance identifies VRE‐colonized patients who may benefit from targeted antimicrobial prophylaxis and enhanced infection prevention measures to prevent VRE spread. The relationship between rifaximin receipt and VRE colonization warrants further study. The identification of similar VRE isolates may suggest linked transmission during pre‐transplant hospitalizations, which should be further investigated in prospective studies.