Transcript Style B 36 by 48 wide - University of Chicago

MRSA and the Cook County Jail: Analysis of Isolates That May Be From a
Reservoir of Community- Associated Infections
Lena Kuo, MD, Robert Daum, MD, Susan Boyle, PhD, Michael David, MD, Daniel Kim
Department of Pediatric Infectious Disease
Introduction
Hypothesis
•Staphylococcus aureus is a common cause of
skin and soft tissue infections, pneumonia, septic
arthritis, osteomyelitis, and sepsis
Jail serves as a reservoir for CA- MRSA
in the community of Chicago
•Methicillin-resistant Staph aureus (MRSA) has
become an increasingly prevalent threat to public
health in the US and worldwide
Specific Aims
•MRSA was originally confined to hospitals, health
care institutions
•Increasingly, MRSA isolates with distinct
genotypes have caused community- associated
infections and outbreaks, notably in populations
without traditional risk factors
•Outbreaks of CA- MRSA have been identified in
multiple settings with crowding and/ or poor
hygienic conditions, including: athletic teams,
daycare, military, jails/prison
•Detainees in prisons and jails are well-recognized
reservoirs for tuberculosis
•Infectious agents that are spread by casual
contact, frequently isolated in asymptomatic
carriers, and difficult to eradicate may spread
among the prison and jail population and then into
the community (such as MRSA)
•Detainment at a jail or prison has become
increasingly prevalent in the adult population; 1 in
110 and 1 in 1656 women have been in jail or
prison; 10.4% of black men between 25-29 were
imprisoned
•Monitoring of etiologic agents of skin infections at
the Cook County Jail between March 2004 and
August 2004: 70.9% (122/ 172) skin infections
grew MRSA
Summary of Culture Results
Cermak Health Services
March- August 2004
MARCH APRIL MAY
JUNE JULY AUGUSTTOTAL
WOUND
23
22
34
33
36
24
172
MRSA
18
13
27
20
26
18
122
%MRSA 78.30% 59.10% 79.40% 60.60% 72.20% 75.00% 70.90%
40
35
• 72% were resistant to only erythromycin and ßlactams
• MLST sequence type 8
• 17% were were multi- drug resistant
• SCCmec type IV
mecA
Materials
ccr 1-3
61 MRSA isolates from infected detainees at the
Cook County Jail, collected between MarchDecember, 2004
Methods
Future Directions
I. Antibiotic Resistance Profiling
II. Multilocus Sequence Typing (MLST):
•Characterization of bacterial isolates using internal
fragment sequences of seven housekeeping genes
•Sequences are between 450-500 bp long
•Different sequences are assigned as different alleles,
determined by comparing sequences to known alleles in
the MLST database
•Alleles at the 7 loci define the allelic profile, or sequence
type
•Unambiguous descriptor for the S. aureus genotype
• 8.1% (3/37) were type 5
• 2.7% (1/37) were type 474
SCCmec typing of jail isolates P3-P5, P27, P57-61 (from left to
right: ladder, positive control, isolates P3-5, P27, positive control,
P57-61)
MLST
1
• Of the 9 isolates characterized by SCCmec
typing, 89% (8/9) were SCCmec type IV
1
5
• 89% (8/9) were PVL positive
Type 8
Type 5
Type 1
Type 474
T
U
G
U
S
A
JU
LY
JU
N
E
Y
A
M
R
IL
References
C P3 P4 P5 P27 C P57 P58 P59 P60 P61
SCCmec: “Staphylococcal chromosomal cassette mec,” a
mobile genetic element that contains the mecA region
Daum et al. JID 2002; 186: 1344-7
•Characterize the clones associated with new
colonization
• 2.7% (1/37) were type 1
32
P
PVL
• 86.5% (32/37) were type 8
III. SCCmec Typing:
0
•Determine MRSA and MSSA new colonization
rate of detainees at the Cook County Jail
•Determine risk factors associated with new
MRSA or MSSA colonization at the Cook
County Jail
• Of the 37 isolates characterized, MLST were as
follows:
MLST can identify relatedness of isolates and identify
clones with serious disease
5
mecR1
/PB
MLST typing of jail isolates P11- P17; confirmation gel electrophoresis
of PCR product
Secondary to the nature of the housekeeping gene, allelic
profile of isolates change very slowly over time
10
A
4. SCCmec type IV is commonly found in CAMRSA isolates
5. Initial results of molecular characterization
of jail isolates suggest that MRSA strains
found in the jail represent the same, or
closely related, strains found in the
community of Chicago
MRSA
R
C
H
2. ST-8 is a very common sequence type found in
CA-MRSA infections
3. ST-1 has been associated with severe
staphylococcal sepsis in children (MW2 CAMRSA in North Dakota, 1999)
WOUND
A
1. Antibiotic resistance profile is in concordance
with the antibiotic resistance profile found in
CA-MRSA strains
II. Multilocus Sequence Typing (37 isolates)
15
M
• Resistant to erythromycin and ß-lactam
antibiotics
• 11% were resistant to ß- lactams only
25
Cermak Health Services, March-August 2004
Of the jail isolates molecularly characterized, the
majority are:
III. SCCmec Typing (9 isolates)
I. Antibiotic Resistance Profiles (18 isolates)
SCCmec are classified into 5 types based on
polymorphisms on conserved genes
30
Conclusions
2. Compare predominant clones found in the jail to
those found in the community
mecA gene: encodes PBP2a, a penicillin binding protein
that has decreased affinity for ß-lactam antibiotics
20
Results
1. The colonizing clones of MRSA found within the
Cook County Jail;
•Reservoirs for community- associated MRSA have
yet to be identified
NO. OF CULTURES
By multilocus sequence typing (MLST), SCCmec
typing, and toxin gene identification (PVL),
preliminarily determine:
Results
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Baillargeon J, Kelley MF, Leach CT, Baillargeon G, Pollack BH.
Methicillin-Resistant Staphylococcal aureus Infection in the Texas
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Bonczar TP and Beck AJ. Lifetime Likelihood of Going to State or
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Daum R, Ito T, Hiramatsu K, Hussain F, Mongkolrattanothai K,
Jamklang M, Boyle-Vavra S. A Novel Methicillin-Resistance
Cassette in Community-Acquired Methicillin-Resistant
Staphylococcus aureus Isolates of Diverse Genetic Backgrounds.
JID 2002; 186: 1344-7.
Ma XX, Ito T, Tiensasitorn C, Jamklnag M, Chongtrakool P, BoyleVavra S, Daum RS, Hiramatsu K. A Novel Type of Staphylococcal
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Antimicrob Agents and Chemother 2002; 46: 1147-52.
Mongkolrattanothai K, Boyle-Vavra S, Kahana MD, Daum RS.
Severe Staphylococcal aureus Infections Caused By Clonallyrelated Community- qcquired Methicillin-suseptible and MethicillinResistant Isolates. Clin Inf Dis 2003; 37: 1050-8.