OVERVIEW OF HUMAN INFECTIONS ACQUIRED IN HEALTHCARESETTINGS

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OVERVIEW OF HUMAN INFECTIONS ACQUIRED IN
HEALTHCARE-SETTINGS

• David Jay Weber, M.D., M.P.H.
• Professor of Medicine, Pediatrics and
  Epidemiology
• Associate Chief of Staff, UNC Health Care
• Medical Director, Hospital Epidemiology and
  Occupational Health
• University of North Carolina at Chapel Hill

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PERSONS AT RISK OF INFECTIONIN HEALTHCARE
FACILITIES

• Healthcare workers (HCWs)
• Patients
• Visitors

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MAJOR INFECTIOUS RISKS FOR HEALTHCARE WORKERS

• Bloodborne pathogens
• Via percutaneous or mucosal exposure
• Major risks HBV, HCV, HIV
• Airborne or droplet transmitted diseases
• Varicella, measles, pertussis, meningococcal
  infection, influenza, other respiratory viruses
  (e.g., RSV, SARS)
• Contact transmitted diseases (direct, indirect)
• C. difficile, MRSA, herpes simplex, adenovirus
  (keratoconjunctivitis)

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RISKS OF BIOTERRORIST AGENTS

• Person-to-person transmission
• Smallpox (A, C)
• Pneumonic plague (D)
• Cutaneous anthrax (C)
• Viral hemorrhagic fevers (A, C)

• Potential fomite transmission
• Smallpox
• Anthrax
• Q fever
• Plague
• Many agents are potential laboratory hazards

A, airborne C, contact
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Total SARS Cases and Percent Healthcare Workers
by Country

• Total cases 8,096 (774 deaths, mortality rate
  9.6)
• Cases in HCWs 1,706 (21)

HCWs
Total cases
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BLOODBORNE PATHOGENSTRANSMITTED BY NEEDLESTICKS

• Ebola virus infection
• Herpes simplex I
• Leptospirosis
• Malaria
• Marburg VHF
• Mycobacterium marinum
• Mycoplasma caviae infection
• Rocky Mountain spotted fever
• Syphilis
• Toxoplasmosis
• Tuberculosis
• Varicella zoster
• West Nile

• Big 3
• Hepatitis B
• Hepatitis C
• HIV
• Others
• Argentinian VHF (Junin virus)
• Blastomycosis
• Brucellosis
• Corynebacterium diphtheria
• Cyrptococcosis
• Dengue
• Diphtheria

Tarantola A, et al. AJIC 200634367-75
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RISKS OF PERCUTANEOUS EXPOSURES
1 Teo E-K, Lok ASF. UpToDate 2007 HNANES IV,
1999-2004 2 Armstrong GL, et al. Ann Intern Med
2006144705-14 NHANES IV, 1999-2002 3
McQuillan GM, et al. J AIDS 200641651-56
NHANES IV, 1999-2002
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EXPOSURES BY DISEASE
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UNC OHS EVALUATIONS, 2006-07
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RECOMMENDED VACCINES FOR HCWsCDC, ACIP, HICPAC

• Hepatitis B (OHSA required)
• Influenza
• Measles (MMR preferred)
• Mumps (MMR preferred)
• Rubella (MMR preferred)
• Varicella (V)
• Tetanus (Tdap)
• Diphtheria (Tdap)
• Pertussis (Tdap)
• Vaccina? (smallpox)
• Required at UNC

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Estimated Incidence of HBV infections among HCWs
and General Population, United States, 1985-1999
Healthcare Workers
General U.S. Population
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POST-EXPOSURE PROPHYLAXIS

• Animal bite wound
• Avian influenza
• Anthrax
• Hepatitis A
• Hepatitis B
• HIV occupational exposure
• Influenza A
• Influenza B
• Measles
• Rabies
• Human bite wound

• Invasive H. influenzae
• Meningococcal infection
• Pertussis
• Smallpox
• Syphilis
• Tuberculosis
• Varicella-zoster
• Not available
• Mumps, SARS, parvovirus B19, hepatitis C

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VISITORS

• Visitors may acquire a communicable disease or
  serve as a source of infection Risk has not
  been quantified
• Visitors as a source of infection
• Influenza, RSV, measles, varicella, pertussis,
  SARS
• Acquisition of colonization/infection by visitors
• SARS, MRSA
• Visitors may act a vector for transferring
  infection
• B. cepecia
• Recent CDC Isolation Guidelines makes no
  recommendation for screening visitors for
  infection or requiring use of PPE by visitors

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HEALTHCARE-ASSOCIATED INFECTIONS IMPACT

• 1.7 million infections per year
• 98,987 deaths due to HAI
• Pneumonia 35,967
• Bloodstream 30,665
• Urinary tract 13,088
• SSI 8,205
• Other 11,062
• 6th leading cause of death (after heart disease,
  cancer, stroke, chronic lower respiratory
  diseases, and accidents)1

1 National Center for Health Statistics, 2004
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CHALLENGES IN THE PREVENTION AND MANAGEMENT OF
HEALTHCARE-ASSOCIATED INFECTIONS

• Changing population of hospital patients
• Increased severity of illness
• Increased numbers of immunocompromised patients
• Shorter duration of hospitalization
• More and larger intensive care and step down
  units
• Growing frequency of antimicrobial-resistant
  pathogens
• Lack of new antibiotics in the pipeline
• Introduction of MDR organisms from the community
  CA-MRSA
• Lack of compliance with hand hygiene
• Future concerns
• Prion diseases, influenza pandemic (H5N1?),
  bioterrorism agents, gene therapy,
  xenotransplantation

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RATES OF HOSPITAL-ASSOCIATED INFECTIONS PER 1,000
PATIENT DAYS
69 Increase
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INCREMENTAL HOSPITAL DAYSDUE TO COMMON INFECTIONS
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MORTALITY RATE OF COMMON HAIs
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FREQUENCY AND COST OF HAIs
Kilgore ML, et al. Med Care 200846101-104 Cost
data from 55 hospitals of the Cardinal Health
MedMined accounting system adjusted to 2007 US
dollars
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COST ESTIMATES FOR HEALTHCARE-ASSOCIATED
INFECTIONS (HAIs)
Anderson DJ, et al. ICHE 200728767-773 Costs
based on literature review 1985-2005 adjusted to
US 1995 dollars
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HAZARDS IN THE ICU
Weinstein RA. Am J Med 199191(suppl 3B)180S
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PREVALENCE ICU (EUROPE)

• Study design Point prevalence rate
• 17 countries, 1447 ICUs, 10,038 patients
• Frequency of infections 4,501 (44.8)
• Community-acquired 1,876 (13.7)
• Hospital-acquired 975 (9.7)
• ICU-acquired 2,064 (20.6)
• Pneumonia 967 (46.9)
• Other lower respiratory tract 368 (17.8)
• Urinary tract 363 (17.6)
• Bloodstream 247 (12.0)

Vincent J-L, et al. JAMA 1995274639
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RISK FACTORS FOR ICU-ACQUIRED INFECTIONS
(95 CI)
(1.01-1.43)
(1.16-1.57)
(1.20-1.60)
(1.19-1.69)
(1.51-2.03)
(1.75-2.44)
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RISK FACTORS FOR ICU-ACQUIRED INFECTIONS
(95 CI)
(1.56-4.13)
(5.51-14.70)
(9.33-24.14)
(19.43-48.67)
(37.90-96.25)
(48.18-120.06)
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NHSN

• NHSN National Healthcare Safety Network -
  Consists of 211 hospitals from 40 states
  reporting data to CDC using standardized
  definitions
• Premiere surveillance system in US for nosocomial
  infections (infection not present at admission)
• Most recent data 2006
• NHSN drawbacks
• Not a randomized selection of US hospitals
• Participating hospitals vary over time

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Kollef MH, et al. Chest 2004321396
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VENTILATOR-ASSOCIATEDPNEUMONIA RATE NHSN, 2006
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CENTRAL LINE-ASSOCIATED BSI RATENHSN, 2006
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100,000 LIVES CAMPAIGNVAP AND CR-BSI BUNDLES

• VAP Bundle
• Elevation of the head of the bed to between 30
  and 45 degrees
• Daily sedation vacation and daily assessment of
  readiness to extubate
• Peptic ulcer disease (PUD) prophylaxis
• Deep venous thrombosis (DVT) prophylaxis (unless
  contraindicated)

• CR-BSI
• Hand hygiene
• Maximal barrier precautions
• Chlorhexidine skin antisepsis
• Optimal catheter site selection, with subclavian
  vein as the preferred site for non-tunneled
  catheters
• Daily review of line necessity, with prompt
  removal of unnecessary lines

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VAP Ventilator-Associated Pneumonia
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CR-BSI Central line-associated bloodstream
infections
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NHSN

• Comments on variation in rates
• Variation in infection rates among different ICUs
  lt5-fold
• Variation in infection rates among different
  healthcare facilities for same type of ICU
  gt90-fold
• Variation in rates among different healthcare
  facilities not explored
• CDC data often used to evaluate trends however,
  data does not meet strict criteria for a cohort
• Data quality compromised by local sites ability
  to apply CDC definitions and inaccuracy of CDC
  definitions

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HAIs ADVANTAGES OF COMPREHENSIVE SURVEILLANCE
Weber DJ, et al. ICHE
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CHAIN OF INFECTION

• Causative agent
• Susceptible host
  Reservoir
• Inoculating dose
  Portal of exit
• 
  
• Portal of entry
  Environmental
• 
  survival
• Mode of transmission

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KEY INFECTION CONTROL INTERVENTIONS

• Surveillance
• Isolation (based on transmission mechanism)
• Contact via direct or indirect contact gloves,
  gowns
• Droplet via large droplets (lt3 feet) mask,
  private room
• Airborne via small droples (gt3 feet) N95
  respirator, private room, negative air pressure,
  gt12 air exchanges per hour, direct out exhausted
  air
• Hand hygiene
• Proper disinfection and sterilization (devices,
  environment)

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PROBLEM PATHOGENS

• Drug Resistant
• Methicillin-resistant S. aureus (MRSA)
• Vancomycin-resistant Enterococcus (VRE)
• MDR and XDR M. tuberculosis
• MDR Acintobacter
• MDR P. aeruginosa
• ESBL Klebsiella, Enterobacter, E. coli

• Others
• Aspergillus sp.
• Clostridium difficile
• Influenza A and B
• Legionella sp.
• Mucor sp.
• Norovirus
• RSV

ESBL, extended spectrum beta-lactamace producer
MDR multi-drug resistant
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ANTIBIOTIC RESISTANCE IN HOSPITALS FACTORS
CONTRIBUTING TO SPREAD IN HOSPITALS

• Greater severity of illness of hospitalized
  patients
• More severely immunocompromised patients
• Newer devices and procedures in use
• Increased introduction of resistant organisms
  from the community
• Ineffective infection control isolation
  practices (esp. compliance)
• Increased use of antimicrobial prophylaxis
• Increased use of polymicrobial antimicrobial
  therapy
• High antimicrobial use in intensive care units

Source Shlaes D, et al. Clin Infect Dis
199725684-99.
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Environments Where Antibiotic Resistance Develops
and Their Relationships
Daycare
Nursing Homes
Foreign
Homecare
Tertiary Hospitals
Community
Community Hospitals

VA
Feedlots
Adapted from B. Murray
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Progression of Methicillin Resistance S. aureus
Among ICU Patients
63
CDC. Available at http//www.cdc.gov/ncidod/hip/A
RESIST/ICU_RESTrend1995-2004.pdf. Accessed August
30, 2005. Lowy FD. J Clin Invest.
20031111265-1273.
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Rates of CDD Tripled in U.S. Hospitals between
2000 and 2005
Any diagnosis Primary
From McDonald LC, et al. Emerg Infect Dis.
200612(3)409-15 and unpublished CDC data
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DEALING WITH RESISTANT PATHOGENS

• Community
• Provide recommended vaccines
• Avoid unnecessary antibiotics
• Use appropriate drug to cover antibiotic
  resistant pathogens
• Provide appropriate dose and duration
• Use short course therapy if validated

• Hospital
• Provide recommended vaccines
• Avoid unnecessary antibiotics
• Practice appropriate infection control
• Avoid prophylactic therapy unless supported by
  scientific evidence
• Use appropriate drug to cover antibiotic
  resistant pathogens
• Provide appropriate dose and duration
• Use short course therapy if validated
• Practice de-escalation
• Use early IV to PO switch

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Improved Patient Outcomes Associated with Proper
Hand Hygiene
Ignaz Philipp Semmelweis (1818-1865)
Chlorinated Lime Hand Antisepsis
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MATERNAL MORTALITY, VIENNA MATERNITY HOSPITAL,
1841-1855
MDs - Hand washing with chloride of lime
?
Loudin I. Death in Childbirth. Oxford Press,
1992
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How Is Our Track Record on Handwashing in
Healthcare Facilities?

• A review of 34 published studies of handwashing
  adherence among healthcare workers found that
  adherence rates varied from 5 to 81
• The average adherence rate was only 40

Average Handwashing Adherence of Personnel in 34
Studies
Average
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EFFECTIVENESS OF HAND HYGIENE
Pittet D, et al. Lancet 20003561307-12.
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Ignaz SemmelweisFour Years of Infection Control
Clin Infect Dis 199520691
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SUMMARY

• Healthcare workers at risk for acquisition of
  infectious diseases especially airborne/droplet
  (tuberculosis, influenza, varicella, measles) and
  bloodborne (HCV)
• Prevention Appropriate immunizations, use of
  PPE, recognition of exposure with PEP
• Healthcare-associated infections are a major
  source of morbidity and mortality in US (6th
  leading cause of death)
• Prevention Surveillance, prompt recognition of
  potentially communicable diseases with
  implementation of isolation, hand hygiene, and
  proper disinfection/sterilization of equipment