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Case-Control Investigation of a Drug-Resistant Acinetobacter baumannii Outbreak at a Regional Medical Center in Eastern Kentucky, 2010. Alexander J. Freiman, MPH, CPH CDC/CSTE Applied Epidemiology Fellow Kentucky Department for Public Health June 15, 2011. Background. A. baumannii - PowerPoint PPT Presentation
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1
Case-Control Investigation of a Drug-Resistant
Acinetobacter baumannii Outbreak at a Regional
Medical Center in Eastern Kentucky, 2010
Alexander J. Freiman, MPH, CPH CDC/CSTE Applied Epidemiology
FellowKentucky Department for Public
HealthJune 15, 2011
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Background A. baumannii
Aerobic, gram negative bacteria Persist in environment Person-person or direct contact Drug resistance
Outbreaks of multi drug-resistant (MDR) A. baumannii in healthcare setting a growing concern Healthcare-associated infection Especially in intensive care units (ICUs)
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Background Kentucky Department for Public
Health (KDPH) notified of Acinetobacter outbreak in September, 2010 66 cases initially reported
Assistance requested from KDPH New Infection Preventionist Reported gaps in infection control
process Hand hygiene Lacked comprehensive environmental
cleaning protocols
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Background Response team assembled from
KDPH and began on-site evaluation CDC collaboration
Medical epidemiologist Laboratory experts
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Objectives Two main objectives
Identify risk factors associated with recovery of A. baumannii in hospitalized ICU patients
Investigate potential environmental sources of A. baumannii in healthcare facility
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Methods Study Design
Case-control Case definition:
Laboratory-confirmed cultures of MDR A. baumannii ≥72 hours after hospital admission
ICU admission January-September 2010
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Methods Control definition
ICU admission December 2009-October 2010 No history of A. baumannii infection in
chart Controls were matched to cases 1:1
ICU admission date ICU length of stay
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Methods Abstracted information from medical
records Demographics Admission/discharge Medical history Laboratory results Consultations Procedures Medications
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Methods Statistical Analysis
Frequencies T-test, Chi square test, Fisher’s exact
test Odds ratios between potential risk
factors and MDR A. baumannii recovery using logistic regression
Univariate Multivariate
Conducted using SPSS software
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Methods Collected environmental samples
using wide sponge culturettes Site selection
High touch surfaces in areas with infected patients
Identified in previous studies CDC recommendations
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Methods One sample taken at each of five
sites ICU glucometer ICU medication dispensing unit ICU nursing station digital camera Portable x-ray machine Countertops in radiology unit
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Methods Five environmental and three
patient samples sent to state and CDC labs for pulsed field gel electrophoresis (PFGE) typing
Similarity between strains from environmental and patient samples determined using computer software
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Case Selection
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Case Selection
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Case Selection
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Case Selection
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Results
Jan Feb Mar Apr May Jun Jul Aug Sep02468
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Epidemic curve for MDR A. baumannii cases in an eastern Kentucky regional
medical center, 2010 (N=30)
Month
Num
ber
of c
ases
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ResultsSelected Characteristics of Cases and Controls
Characteristic Casen (%)
Controln (%) P value
Race/EthnicityCaucasian 29 (97) 29 (97) 1.00Non-Hispanic 29 (97) 29 (97) 1.00
Age (in years)Mean 68 67 0.72Median 70 69Range 40-87 38-105
SexFemale 12 (40) 17 (57) 0.30
ComorbidityDiabetes 18 (60) 10 (33) 0.04
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Results
Source of MDR A. baumannii culture from cases (N=30)
Source n (%)Respiratory 19 (63)Blood 5 (17)Wound 4 (13)Urine 2 (7)
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Results
Environmental culture results Site ResultPortable x-ray machine PositiveICU nursing station digital camera
Positive
ICU medication dispensing unit NegativeICU glucometer NegativeCountertops in radiology unit Negative
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Results
Patient 4 from another healthcare facility
*
*
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Results
Patient 4 from another healthcare facility
*
*
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Results
Patient 4 from another healthcare facility
*
*
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Results
Patient 4 from another healthcare facility
*
*
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ResultsCrude Associations for Risk Factors and Positive MDR
A. baumannii CultureRisk Factors OR P value 95% Confidence IntervalReceived subcutaneous or intravenous insulin 4.97 0.014* (1.39, 17.82)Fingersticks performed 5.02 0.025* (1.23, 20.49)Total number of chest x-ray procedures 1.10 0.032* (1.01, 1.21)Diabetic 3.00 0.041* (1.05, 8.60)Central line performed 3.14 0.043* (1.03, 9.55)Decubitis ulcer present 2.62 0.072 (0.92, 7.46)Consulted with occupational therapist 3.08 0.094 (0.82, 11.50)Did patient have cardiovascular issues 3.27 0.107 (0.77, 13.83)Obese 2.41 0.111 (0.82, 7.10)*p value ≤ 0.05
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ResultsCrude Associations for Risk Factors and Positive MDR
A. baumannii CultureRisk Factors OR P value 95% Confidence IntervalReceived subcutaneous or intravenous insulin
4.97 0.014* (1.39, 17.82)
Fingersticks performed 5.02 0.025* (1.23, 20.49)Total number of chest x-ray procedures 1.10 0.032* (1.01, 1.21)Diabetic 3.00 0.041* (1.05, 8.60)Central line performed 3.14 0.043* (1.03, 9.55)Decubitis ulcer present 2.62 0.072 (0.92, 7.46)Consulted with occupational therapist 3.08 0.094 (0.82, 11.50)Did patient have cardiovascular issues 3.27 0.107 (0.77, 13.83)Obese 2.41 0.111 (0.82, 7.10)*p value ≤ 0.05
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ResultsCrude Associations for Risk Factors and Positive MDR
A. baumannii CultureRisk Factors OR P value 95% Confidence IntervalReceived subcutaneous or intravenous insulin 4.97 0.014* (1.39, 17.82)Fingersticks performed 5.02 0.025* (1.23, 20.49)Total number of chest x-ray procedures 1.10 0.032* (1.01, 1.21)Diabetic 3.00 0.041* (1.05, 8.60)Central line performed 3.14 0.043* (1.03, 9.55)Decubitis ulcer present 2.62 0.072 (0.92, 7.46)Consulted with occupational therapist 3.08 0.094 (0.82, 11.50)Did patient have cardiovascular issues 3.27 0.107 (0.77, 13.83)Obese 2.41 0.111 (0.82, 7.10)*p value ≤ 0.05
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ResultsAdjusted Associations for Risk Factors and MDR
A. baumannii Culture for Sampled EquipmentRisk Factors OR P value 95% Confidence IntervalFingersticks performed* 4.34 0.048 (1.01, 18.62)Total number of chest x-ray procedures† 1.10 0.065 (0.99, 1.22)Decubitis ulcer photographed* 2.71 0.083 (0.88, 8.37)*Model adjusted for age, type of admission, and mechanical ventilation†Model adjusted for age, type of admission, and fingersticks
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ResultsAdjusted Associations for Risk Factors and MDR
A. baumannii Culture for Sampled EquipmentRisk Factors OR P value 95% Confidence IntervalFingersticks performed* 4.34 0.048 (1.01, 18.62)Total number of chest x-ray procedures† 1.10 0.065 (0.99, 1.22)Decubitis ulcer photographed* 2.71 0.083 (0.88, 8.37)*Model adjusted for age, type of admission, and mechanical ventilation†Model adjusted for age, type of admission, and fingersticks
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Discussion Lab cultures identified two possible
sources for MDR A. baumannii transmission to patients in the facility Portable chest x-ray machine Digital camera used for wound
photography PFGE pattern similarity between
environmental and patient samples matched between 92-100%
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Discussion Epidemiologic analysis suggests
receiving fingersticks is a risk factor for becoming a case
Breakdowns in disease prevention activities Hand hygiene Cleaning shared equipment
Lack of clear equipment-cleaning responsibility might have contributed to ongoing transmission
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Discussion Limitations
Generalizability Small sample
Reliability Cases: Controls only 1:1
Validity Lack of true electronic medical records Incomplete line listing from healthcare
facility
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Discussion Have procedures in place to clean all
shared equipment Recognition of an outbreak and
immediate implementation of effective controls is CRITICAL to preventing MDR A. baumannii transmission in the healthcare setting
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AcknowledgmentsKentucky Department for Public HealthMargaret A. Riggs, PhD, MPH, MAFontaine Sands, DrPH, MSN, CICDavid R. Reese, MA, MPH, FRSPHKraig E. Humbaugh, MD, MPHDoug Thoroughman, PhD, MSRobert L. Brawley, MD, MPH, FSHEA
Centers for Disease Control and Prevention, Division of Healthcare Quality and PromotionAlexander J. Kallen, MD, MPHJudith Noble-Wang, PhDHeather A. O’Connell, PhD
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Acknowledgments This study was supported in part by
an appointment to the Applied Epidemiology Fellowship Program administered by the Council of State and Territorial Epidemiologists (CSTE) and funded by the Centers for Disease Control and Prevention (CDC) Cooperative Agreement Number 5U38HM000414.
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Contact InformationAlex Freiman
CDC/CSTE Applied Epidemiology Fellow
Kentucky Department for Public Health
Phone: (502)564-3261 x3278Email: [email protected]