The Alarming Rise of The Alarming Rise of CA-MRSACA-MRSA

at UMass-Memorialat UMass-Memorial Medical Center Medical Center

David M. Bebinger, M.D.David M. Bebinger, M.D.

Assistant ProfessorAssistant Professor

Division of Infectious DiseasesDivision of Infectious Diseases

UMass-Memorial Medical CenterUMass-Memorial Medical Center

July 30, 2007July 30, 2007

MRSA Epidemiology StudyMRSA Epidemiology StudyParticipantsParticipants

David M. Bebinger, MD Richard T. Ellison III, MD Ranjan Chowdhry, MD Rose Erlichman, RN, BSN, CIC

MRSA Trends at UMMCMRSA Trends at UMMC

October 2003 through September 2006

0

10

20

30

40

50

60

70

80

90

OCT DEC FEB APR JUN AUG OCT DEC FEB APR JUN AUG OCT DEC FEB APR JUN AUG

Number of New Cases

CA

HCA

NOS

Study ObjectiveStudy Objective

To identify demographic features associated with acquisition of CA-MRSA as compared to acquisition of healthcare-associated (HCA) or nosocomially acquired (Noso) MRSA.

MethodsMethods A retrospective record review of patients A retrospective record review of patients

identified previously by the infection control identified previously by the infection control department as being newly diagnosed with an department as being newly diagnosed with an infection or colonization with MRSA between infection or colonization with MRSA between October 1, 2003 and September 30, 2006.October 1, 2003 and September 30, 2006.

All cases were evaluated by infection control practitioners and categorized as CA, HCA, or Noso.

Of 2920 patients meeting this inclusion criteria Of 2920 patients meeting this inclusion criteria 879 were chosen for chart review879 were chosen for chart review

Total Number of New MRSA Total Number of New MRSA CasesCases

Total CA HCA Noso

2003-4 669 93 378 198

2004-5 986 278 456 252

2005-6 1265 557 468 240

Total 2920 928 1302 690

Information recorded from electronic Information recorded from electronic record review:record review:AgeAgeSexSexRaceRaceZip codeZip codeCulture siteCulture siteHealthcare siteHealthcare siteAmount of exposure to the UMass systemAmount of exposure to the UMass system

MethodsMethods

Average Age of Patient by Year

*includes neonatal infections

CA HCA *Noso Total

2003-4 42.0 66.6 58.0 55.5

2004-5 34.3 57.9 55.9 49.4

2005-6 35.3 60.1 56.2 50.5

Total 37.2 61.5 56.7

P<0.0001

0

10

20

30

40

50

60

70

2003-4 2004-5 2005-6

P<0.001

Age (years)

CA

HCA

Noso

Average Age of Patient by Year

Percentage of Male PatientsPercentage of Male Patients

CA HCA Noso Total

2003-4 47 52 56 50.7

2004-5 52 51 61 54.7

2005-6 56 55 59 56.7

TOTAL 51.7 52.7 58.7

Percentage of Caucasian Patients

CA HCA Noso

2003-4 76/84 83/90 82/86

2004-5 61/73 84/90 75/88

2005-6 72/77 76/84 81/85

Total 73/83 85/93 83/91

% of total/Adjusted for unlisted raceP<0.003

0

10

20

30

40

50

60

70

80

90

2003-4 2004-5 2005-6

P=0.003Percent Caucasion

CA

HCA

Noso

Ethnicity

MRSA Epidemiology StudyMRSA Epidemiology StudyPercentage of Cultures Obtained From Inpatient and Emergency Department By Year

Inpatient

Total

Inpatient

CA

Inpatient

HCA

ED

Total

2003-4 75 58 68 9

2004-5 64 48 59 10

2005-6 57 22 59 16

Total # CA HCA Noso

2003-4 67.7 43 34.4

2004-5 80 49 20

2005-6 86 49 24

Percentage of Cultures labeled Percentage of Cultures labeled “Wound”“Wound”

0

10

20

30

40

50

60

70

80

90

100

2003-4 2004-5 2005-6

CA

HCA

Noso

Percentage of Cultures labeled “Wound”

Patients With Bacteremia Patients With Bacteremia by Yearby Year

CA HCA Noso Total

2003-4 9 12 14 35

2004-5 7 11 4 22

2005-6 5 11 4 20

Healthcare exposure: Healthcare exposure: >15 days exposed to >15 days exposed to

UMass SystemUMass System

CA HCA Noso

2003-4 16.1 58.1 66.7

2004-5 9 55 63

2005-6 7 51 57

0

10

20

30

40

50

60

70

2003-4 2004-5 2005-6

Percentage of Category

CA

HCA

Noso

Healthcare exposure: >15 days exposed to

UMass System

Healthcare exposure: Healthcare exposure: <6 days exposed to <6 days exposed to

UMass SystemUMass System

CA HCA Noso

2003-4 58 20 5

2004-5 72 24 6

2005-6 77 19 6

ALL 67 21 6 P<0.001

P<0.025

0

10

20

30

40

50

60

70

80

90

2003-4 2004-5 2005-6

P<0.001Percentage of Category

CA

HCA

Noso

Healthcare exposure: <6 days exposed to

UMass System

2005-6 Antibiogram Data 2005-6 Antibiogram Data

Erythro Levo Clinda TMP/

SMX

Tetra-cyclin

CA 5 76 82 99 94

HCA 6 36 47 98 92

Noso 22 2626 3333 100100 9696

AllAll 5 47 55 99 94

Indicates percentage of isolates sensitive to given agent

0

20

40

60

80

100

120

Erythromycin Levofloxacin Clindamycin TMP/SMX Tetracycline

Percentage of Category

CA

HCA

Noso

2005-6 Antibiogram Data

A Caveat to Clindamycin DataA Caveat to Clindamycin Data

““Our lab does not Our lab does not correctly test for correctly test for resistance to resistance to clindamycin. In clindamycin. In order to do this order to do this properly you have to properly you have to perform a D-test.”perform a D-test.”

Most Mec IV isolates Most Mec IV isolates are D-test negativeare D-test negative

Jennifer Daly, MD

The incidence of CA-MRSA at UMMMC now consistently exceeds the incidence of HCA-MRSA and Noso-MRSA.CA-MRSA patients are younger, more ethnically diverse, and are primarily presenting with skin and soft tissue infections.MRSA should now be considered a possible pathogen in ALL patients with possible S. aureus infectionsThe decreasing level of prior contact with our healthcare system suggests that the strain is established in our community.

ConclusionsConclusions

RamificationsRamificationsCurrent infection control practices are unlikely Current infection control practices are unlikely to contain the continued spread of MRSA – to contain the continued spread of MRSA – which will have major implications in both the which will have major implications in both the overall approach to the management of overall approach to the management of patients with MRSA, as well as strategies to patients with MRSA, as well as strategies to prevent healthcare associated illnesses such prevent healthcare associated illnesses such as surgical site infectionsas surgical site infections

Mec IV, USA 300 and USA 400 strains may Mec IV, USA 300 and USA 400 strains may have a fitness advantage above their ability to have a fitness advantage above their ability to survive in the presence of beta-lactam survive in the presence of beta-lactam antibiotics antibiotics