57793_CH00_FM_ARIAS.qxd 1/21/09 5:16 AM Page i OUTBREAK INVESTIGATION, PREVENTION, AND CONTROL IN HEALTH CARE SETTINGS Critical Issues for Patient Safety Second Edition Kathleen Meehan Arias MS, MT (ASCP), CIC Arias Infection Control Consulting,LLC Crownsville,Maryland JONES AND BARTLETT PUBLISHERS Sudbury, Massachusetts BOSTON TORONTO LONDON SINGAPORE 57793_CH00_FM_ARIAS.qxd 1/21/09 5:16 AM Page ii World Headquarters Jones and Bartlett Publishers Jones and Bartlett Publishers International 40 Tall Pine Drive Barb House,Barb Mews Sudbury,MA 01776 London W6 7PA 978-443-5000 United Kingdom [email protected] www.jbpub.com Jones and Bartlett Publishers Canada 6339 Ormindale Way Mississauga,Ontario L5V 1J2 Canada Jones and Bartlett’s books and products are available through most bookstores and online booksellers. To contact Jones and Bartlett Publishers directly,call 800-832-0034,fax 978-443-8000,or visit our web- site www.jbpub.com. 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This publication is designed to provide accurate and authoritative information in regard to the Sub- ject Matter covered.It is sold with the understanding that the publisher is not engaged in rendering legal,accounting,or other professional service.If legal advice or other expert assistance is required, the service of a competent professional person should be sought. Production Credits Publisher:Michael Brown Production Director:Amy Rose Associate Editor:Katey Birtcher Editorial Assistant:Catie Heverling Senior Production Editor:Tracey Chapman Production Assistant:Roya Millard Marketing Manager:Sophie Fleck Manufacturing and Inventory Control Supervisor:Amy Bacus Composition:Achorn International Cover Design:Scott Moden Cover Image:© Daniela Illing/ShutterStock,Inc. Printing and Binding:Malloy,Inc. Cover Printing:Malloy,Inc. Library of Congress Cataloging-in-Publication Data Arias,Kathleen Meehan. Outbreak investigation,prevention,and control in health care settings:critical issues for patient safety / Kathleen Meehan Arias. p.;cm. Rev.ed.of:Quick reference to outbreak investigation and control in health care facilities / Kathleen Meehan Arias.2000. Includes bibliographical references. ISBN-13:978-0-7637-5779-3 (pbk.) ISBN-10:0-7637-5779-9 (pbk.) 1. Health facilities—Sanitation—Handbooks,manuals,etc. 2. Nosocomial infections—Prevention —Handbooks,manuals,etc. 3. Cross infection—Prevention—Handbooks,manuals,etc. I.Arias,Kathleen Meehan.Quick reference to outbreak investigation and control in health care facilities. II.Title. [DNLM: 1. Health Facilities—Handbooks. 2. Infection Control—methods—Handbooks. 3. Dis- ease Outbreaks—Handbooks. 4. Epidemiologic Methods—Handbooks. WX 39 A696o 2010] RA969.A736 2010 614.4'4--dc22 2008029520 6048 Printed in the United States of America 13 12 11 10 09 10 9 8 7 6 5 4 3 2 1 57793_CH00_FM_ARIAS.qxd 1/21/09 5:16 AM Page iii For my wonderful husband,Bob. For his patience, understanding, and support while I worked on the second edition of “the book.” 57793_CH00_FM_ARIAS.qxd 1/21/09 5:16 AM Page iv I am indebted to the contributing authors (colleagues and friends who graciously shared their expertise) and to their families who were under- standing of the time it takes to prepare a manuscript. The author would like to thank Robert Arias, Patti Grant, and James Luby, MD, for reviewing sections of the manuscript and providing con- structive criticism,and Shawn M.Phillips for sharing his mom. Kathleen Meehan Arias 57793_CH00_FM_ARIAS.qxd 1/21/09 5:16 AM Page v Contents Preface to the Second Edition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiii CHAPTER 1.AN INTRODUCTION TO EPIDEMIOLOGY . . . . . . . . . . . 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Definitions Used in Healthcare Epidemiology. . . . . . . . . . . . . . . . . . . . . 1 A Historical Perspective:Some Epidemiological Tidbits. . . . . . . . . . . . 2 The Multifactorial Nature of Disease. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Etiologic Agents of Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Biological Agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Chemical Agents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Physical Agents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Host Factors Affecting Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Environmental Factors Affecting Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Study Methods Used in Epidemiology:The Five Ws—What,Who, Where,When,and Why. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Descriptive Epidemiology:Who,Where,and When. . . . . . . . . . . . . . . . . . . . 7 Person . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Place . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Analytic Epidemiology:Why. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Criteria for Judging Causality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Establishing Causal Relations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 The Epidemiology of Infectious Diseases . . . . . . . . . . . . . . . . . . . . . . . . 14 The Infectious Disease Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Frequently Inapparent Infection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Infection Resulting in Rarely Fatal Clinical Disease. . . . . . . . . . . . . 15 Infection Resulting in Usually Fatal Severe Disease. . . . . . . . . . . . . 15 v 57793_CH00_FM_ARIAS.qxd 1/21/09 5:16 AM Page vi vvii CCOONNTTEENNTTSS The Infectious Disease Process:The Chain of Infection . . . . . . . . . . . . . . . 16 Infectious Agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Reservoirs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Portals of Exit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Modes of Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Portals of Entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Susceptible Host. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Identifying Effective Measures to Control or Prevent the Spread of Infection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Measures Directed at the Reservoir or Source of an Agent. . . . . . . . 26 Measures Directed at Interrupting Transmission . . . . . . . . . . . . . . . 27 Measures Directed at the Host . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Suggested Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 CHAPTER 2. SURVEILLANCE PROGRAMS,PUBLIC HEALTH, AND EMERGENCY PREPAREDNESS . . . . . . . . . . . . . . . . . . . . 33 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Surveillance Programs in Healthcare Settings. . . . . . . . . . . . . . . . . . . 34 Surveillance:What Is It and Why Do It? . . . . . . . . . . . . . . . . . . . . . . . . . 34 Surveillance Programs in Hospitals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Surveillance Programs in Healthcare Settings Other Than Acute Care Hospitals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Surveillance Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Housewide (Comprehensive) Surveillance. . . . . . . . . . . . . . . . . . . . . . . . . . 37 Targeted (Focused) Surveillance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Combining Housewide and Targeted Surveillance . . . . . . . . . . . . . . . . . . . 38 Guidelines for Developing and Evaluating a Surveillance Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Developing a Surveillance Program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Identify the Surveillance Methodology to be Used. . . . . . . . . . . . . . . 39 Assess and Define the Population and Select the Events to be Monitored . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Determine the Time Period for Data Collection. . . . . . . . . . . . . . . . . 44 Select Surveillance Criteria and Case Definitions. . . . . . . . . . . . . . . 44 Determine the Process for Gathering Data. . . . . . . . . . . . . . . . . . . . . 48 Identify How to Calculate Rates and Analyze the Data. . . . . . . . . . . 51 Develop an Interpretive Report. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Determine Who Should Receive the Report . . . . . . . . . . . . . . . . . . . . 56 Develop a Written Surveillance Plan . . . . . . . . . . . . . . . . . . . . . . . . . 56 Evaluating a Surveillance Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 57793_CH00_FM_ARIAS.qxd 1/21/09 5:16 AM Page vii CONTENTS vii Regulations and Requirements Affecting Surveillance Programs in Healthcare Settings. . . . . . . . . . . . . . . . . . . . . . . . . 57 The Healthcare Provider’s Role in Public Health Surveillance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Global Surveillance and Emergency Preparedness . . . . . . . . . . . . . . . 58 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Suggested Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Resources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 CHAPTER 3. OUTBREAKS REPORTED IN ACUTE CARE SETTINGS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 Endemic vs.Epidemic Infections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Organisms Responsible for Hospital-Associated Outbreaks. . . . . . . . 72 Outbreaks Associated with Products,Devices,and Procedures (Common Source Outbreaks) . . . . . . . . . . . . . . . . . 75 Outbreaks Associated with Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Intrinsic Contamination of Products. . . . . . . . . . . . . . . . . . . . . . . . . . 76 Extrinsic Contamination of Products . . . . . . . . . . . . . . . . . . . . . . . . . 76 Noninfectious Adverse Events Related to Products. . . . . . . . . . . . . . 79 Outbreaks Associated with Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 Outbreaks Associated with Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 Gastrointestinal Endoscopy and Bronchoscopy . . . . . . . . . . . . . . . . . 86 Hemodialysis and Peritoneal Dialysis. . . . . . . . . . . . . . . . . . . . . . . . . 87 Outbreaks Associated with Surgery . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Outbreaks Associated with Pseudomonas,Ralstonia, and BurkholderiaSpecies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Outbreaks Associated with Human Carriers or Disseminators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Staphylococcus aureus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Group A Beta-Hemolytic Streptococcus . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 Candidaand NocardiaSpecies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Gram-Negative Organisms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Hepatitis B Virus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Hepatitis C Virus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Human Immunodeficiency Virus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 SalmonellaSpecies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Hepatitis A Virus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 57793_CH00_FM_ARIAS.qxd 1/21/09 5:16 AM Page viii viii CONTENTS Outbreaks Spread from Person to Person by Airborne and Droplet Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Diseases Spread by Airborne Transmission. . . . . . . . . . . . . . . . . . . . . . . . . 94 Measles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Varicella(Chickenpox) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 Diseases Spread by Droplet Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . 98 Respiratory Syncytial Virus (RSV) Infection . . . . . . . . . . . . . . . . . . . 98 Pertussis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 More on Diseases Spread by the Airborne and Droplet Routes . . . . . . . . 100 Outbreaks of Gastroenteritis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Outbreaks of Diseases That Have Environmental Reservoirs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Legionnaire’s Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Epidemiology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Mode of Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 Control Measures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 Aspergillosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 Epidemiology and Mode of Transmission . . . . . . . . . . . . . . . . . . . . . 102 Control Measures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Outbreaks and Pseudo-Outbreaks Associated with a Water Reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 Potable Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 Ice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 Water Baths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 Outbreaks of Nosocomial Pneumonia in Intensive Care Units. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 Outbreaks of Sick Building Syndrome and Building-Related Illness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 Newly Recognized Agents and Sources for Healthcare-Associated Outbreaks. . . . . . . . . . . . . . . . . . . . . . . 112 CandidaSpecies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 Epidemiology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 Control Measures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 Identifying New Risk Factors and Sources for Infection. . . . . . . . . . . . . . 114 The Importance of Personnel and Employee Health . . . . . . . . . . . . . 116 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 Suggested Reading and Resources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 Agencies and Organizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 57793_CH00_FM_ARIAS.qxd 1/21/09 5:16 AM Page ix CONTENTS ix CHAPTER 4. OUTBREAKS REPORTED IN LONG-TERM CARE SETTINGS . . . . . . . . . . . . . . . . . . . . . . . . . 141 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 Endemic Infections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 Risk Factors for Infection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 Epidemic Infections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 Recognizing and Confirming an Outbreak in the Long-Term Care Setting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 Outbreaks of Respiratory Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 Streptococcus pneumoniae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 Epidemiology and Mode of Transmission . . . . . . . . . . . . . . . . . . . . . 145 Control Measures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 Neisseria meningitidis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 Epidemiology and Mode of Transmission . . . . . . . . . . . . . . . . . . . . . 150 Control Measures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 Outbreaks of Respiratory Disease Caused by Other Organisms . . . . . . . 152 Outbreaks of Gastrointestinal Disease . . . . . . . . . . . . . . . . . . . . . . . . . 152 Outbreaks of Conjunctivitis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Outbreaks Caused by Group A Streptococcus. . . . . . . . . . . . . . . . . . . 154 Epidemiology and Mode of Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . 154 Control Measures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 Suggested Reading and Resources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 CHAPTER 5. OUTBREAKS REPORTED IN AMBULATORY CARE SETTINGS . . . . . . . . . . . . . . . . . . . . . . . 163 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Physicians’ Offices and Outpatient Clinics. . . . . . . . . . . . . . . . . . . . . . 166 Outbreaks Associated with Products and Devices (Common Source Outbreaks) . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 Intrinsically Contaminated Products. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 Extrinsically Contaminated Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 Contaminated Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 Control Measures for Preventing Product- and Device-Related Outbreaks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168