Michael A. Jhung

Estimating the Burden of 2009 Pandemic Influenza A (H1N1) in the United States (April 2009–April 2010)

To calculate the burden of 2009 pandemic influenza A (pH1N1) in the United States, we extrapolated from the Centers for Disease Control and Preventions Emerging Infections Program laboratory-confirmed hospitalizations across the entire United States, and then corrected for underreporting. From 12 April 2009 to 10 April 2010, we estimate that approximately 60.8 million cases (range: 43.3-89.3 million), 274,304 hospitalizations (195,086-402,719), and 12,469 deaths (8868-18,306) occurred in the United States due to pH1N1. Eighty-seven percent of deaths occurred in those under 65 years of age with children and working adults having risks of hospitalization and death 4 to 7 times and 8 to 12 times greater, respectively, than estimates of impact due to seasonal influenza covering the years 1976-2001. In our study, adults 65 years of age or older were found to have rates of hospitalization and death that were up to 75% and 81%, respectively, lower than seasonal influenza. These results confirm the necessity of a concerted public health response to pH1N1.

Toxinotype V Clostridium difficile in Humans and Food Animals

Such strains are uncommon causes of severe human disease but may be increasing in incidence.

Epidemiology of 2009 Pandemic Influenza A (H1N1) in the United States

In April 2009, the Centers for Disease Control and Prevention confirmed 2 cases of 2009 pandemic influenza A (H1N1) virus infection in children from southern California, marking the beginning of what would be the first influenza pandemic of the twenty-first century. This report describes the epidemiology of the 2009 H1N1 pandemic in the United States, including characterization of cases, fluctuations of disease burden over the course of a year, the age distribution of illness and severe outcomes, and estimation of the overall burden of disease.

Outbreak of Variant Influenza A(H3N2) Virus in the United States

During an outbreak of H3N2v variant influenza, we identified 306 cases in ten states. Most cases reported agricultural fair attendance and/or contact with swine prior to illness. We found no evidence of efficient or sustained person-to-person transmission of H3N2v.

Gadolinium-Containing Magnetic Resonance Imaging Contrast and Nephrogenic Systemic Fibrosis: A Case-Control Study

BACKGROUND Nephrogenic systemic fibrosis (NSF) is a newly described disorder occurring in persons with renal failure. Gadolinium-based contrast used in magnetic resonance imaging (MRI) has been suggested as a cause. A cluster of patients with NSF was investigated to identify risk factors. Limited preliminary findings from this investigation were presented in the Morbidity and Mortality Weekly Report. STUDY DESIGN Matched case-control. SETTING & PARTICIPANTS Dialysis patients with and without a diagnosis of NSF treated at an academic medical center. PREDICTOR Exposure to gadolinium-based contrast. OUTCOMES & MEASUREMENTS Laboratory and clinical characteristics of NSF. RESULTS 19 of 28 cases identified at the hospital from December 2002 to August 2006 met inclusion criteria and were matched to 57 controls. In univariate analysis, receipt of gadolinium-containing MRI contrast in the preceding year (odds ratio [OR], 7.99; 95% confidence interval, 2.22 to 28.8) was associated with NSF; the measure of association increased as cumulative dose increased. Gadodiamide exposure (OR, 9.83; 95% confidence interval, 2.09 to 46.2) was associated more strongly with NSF than gadoversetamide (OR, 1.82; 95% confidence interval, 0.33 to 10.2). Although not statistically significant, cases were more likely than controls to have undergone primarily peritoneal dialysis in the preceding 6 months. There was no significant difference in receipt of high-dose recombinant erythropoietin between cases and controls. In multivariable analysis, gadolinium contrast exposure (OR, 8.97; 95% confidence interval, 1.28 to 63.0) remained significantly associated with NSF. LIMITATIONS Retrospective design, small sample size, inability to completely evaluate erythropoietin. CONCLUSIONS Receipt of gadolinium-containing MRI contrast is associated with NSF in a dose-dependent manner. The risk associated with gadolinium may differ by contrast agent and dialysis modality. Use of gadolinium-based contrast agents should be avoided when possible in patients with renal failure.

Administrative Coding Data and Health Care-Associated Infections

Surveillance for health care-associated infections (HAIs) using administrative data has received attention from health care epidemiologists searching for efficient means to track infections in their institutions. Several states are also considering electronic surveillance that incorporates administrative data as a means to satisfy an increasing demand for mandatory public reporting of HAIs. International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) discharge diagnosis codes have attributes that make them suitable for detecting HAIs; for example, they may facilitate automated surveillance, freeing up infection control personnel to perform other important tasks, such as staff education and outbreak investigation. However, controversy surrounds the appropriate use of ICD-9-CM data in detecting HAIs, and administrative coding data have been criticized for lacking elements necessary for surveillance. Administrative coding data are inappropriate as the sole means of HAI surveillance but may have value to the health care epidemiologist as a way to augment traditional methods.

Infection Control Assessment of Ambulatory Surgical Centers

CONTEXT More than 5000 ambulatory surgical centers (ASCs) in the United States participate in the Medicare program. Little is known about infection control practices in ASCs. The Centers for Medicare & Medicaid Services (CMS) piloted an infection control audit tool in a sample of ASC inspections to assess facility adherence to recommended practices. OBJECTIVE To describe infection control practices in a sample of ASCs. DESIGN, SETTING, AND PARTICIPANTS All State Survey Agencies were invited to participate. Seven states volunteered; 3 were selected based on geographic dispersion, number of ASCs each state committed to inspect, and relative cost per inspection. A stratified random sample of ASCs was selected from each state. Sample size was based on the number of inspections each state estimated it could complete between June and October 2008. Sixty-eight ASCs were assessed; 32 in Maryland, 16 in North Carolina, and 20 in Oklahoma. Surveyors from CMS, trained in use of the audit tool, assessed compliance with specific infection control practices. Assessments focused on 5 areas of infection control: hand hygiene, injection safety and medication handling, equipment reprocessing, environmental cleaning, and handling of blood glucose monitoring equipment. MAIN OUTCOME MEASURES Proportion of facilities with lapses in each infection control category. RESULTS Overall, 46 of 68 ASCs (67.6%; 95% confidence interval [CI], 55.9%-77.9%) had at least 1 lapse in infection control; 12 of 68 ASCs (17.6%; 95% CI, 9.9%-28.1%) had lapses identified in 3 or more of the 5 infection control categories. Common lapses included using single-dose medication vials for more than 1 patient (18/64; 28.1%; 95% CI, 18.2%-40.0%), failing to adhere to recommended practices regarding reprocessing of equipment (19/67; 28.4%; 95% CI, 18.6%-40.0%), and lapses in handling of blood glucose monitoring equipment (25/54; 46.3%; 95% CI, 33.4%-59.6%). CONCLUSION Among a sample of US ASCs in 3 states, lapses in infection control were common.

Human Infections With Influenza A(H3N2) Variant Virus in the United States, 2011–2012

BACKGROUND. During August 2011-April 2012, 13 human infections with influenza A(H3N2) variant (H3N2v) virus were identified in the United States; 8 occurred in the prior 2 years. This virus differs from previous variant influenza viruses in that it contains the matrix (M) gene from the Influenza A(H1N1)pdm09 pandemic influenza virus. METHODS. A case was defined as a person with laboratory-confirmed H3N2v virus infection. Cases and contacts were interviewed to determine exposure to swine and other animals and to assess potential person-to-person transmission. RESULTS. Median age of cases was 4 years, and 12 of 13 (92%) were children. Pig exposure was identified in 7 (54%) cases. Six of 7 cases with swine exposure (86%) touched pigs, and 1 (14%) was close to pigs without known direct contact. Six cases had no swine exposure, including 2 clusters of suspected person-to-person transmission. All cases had fever; 12 (92%) had respiratory symptoms, and 3 (23%) were hospitalized for influenza. All 13 cases recovered. CONCLUSIONS. H3N2v virus infections were identified at a high rate from August 2011 to April 2012, and cases without swine exposure were identified in influenza-like illness outbreaks, indicating that limited person-to-person transmission likely occurred. Variant influenza viruses rarely result in sustained person-to-person transmission; however, the potential for this H3N2v virus to transmit efficiently is of concern. With minimal preexisting immunity in children and the limited cross-protective effect from seasonal influenza vaccine, the majority of children are susceptible to infection with this novel influenza virus.

Outbreak of influenza A (H3N2) variant virus infection among attendees of an agricultural fair, Pennsylvania, USA, 2011.

Avoiding or limiting contact with swine at agricultural events may help prevent A(H3N2)v virus infections in such settings.

Multiphasic Approach Reveals Genetic Diversity of Environmental and Patient Isolates of Mycobacterium mucogenicum and Mycobacterium phocaicum Associated with an Outbreak of Bacteremias at a Texas Hospital

ABSTRACT Between March and May 2006, a Texas hospital identified five Mycobacterium mucogenicum bloodstream infections among hospitalized oncology patients using fluorescence high-performance liquid chromatography analysis of mycolic acids. Isolates from blood cultures were compared to 16 isolates from environmental sites or water associated with this ward. These isolates were further characterized by hsp65, 16S rRNA, and rpoB gene sequencing, hsp65 PCR restriction analysis, and molecular typing methods, including repetitive element PCR, random amplified polymorphic DNA PCR, and pulsed-field gel electrophoresis (PFGE) of large restriction fragments. Three of five patient isolates were confirmed as M. mucogenicum and were in a single cluster as determined by all identification and typing methods. The remaining two patient isolates were identified as different strains of Mycobacterium phocaicum by rpoB sequence analysis. One of these matched an environmental isolate from a swab of a hand shower in the patients room, while none of the clinical isolates of M. mucogenicum matched environmental strains. Among the other 15 environmental isolates, 11 were identified as M. mucogenicum and 4 as M. phocaicum strains, all of which were unrelated by typing methods. Although the 16S rRNA gene sequences matched for all 14 M. mucogenicum isolates, there were two each of the hsp65 and rpoB sequevars, seven PCR typing patterns, and 12 PFGE patterns. Among the seven M. phocaicum isolates were three 16S rRNA sequevars, two hsp65 sequevars, two rpoB sequevars, six PCR typing patterns, and six PFGE patterns. This outbreak represents the first case of catheter-associated bacteremia caused by M. phocaicum and the first report of clinical isolates from a U.S. hospital. The investigation highlights important differences in the available typing methods for mycobacteria and demonstrates the genetic diversity of these organisms even within narrow confines of time and space.