preoperative staphylococcus aureus nasal screening: impact on reducing staphylococcus aureus...
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Preoperative Staphylococcus aureus Nasal Screening:
Impact on Reducing Staphylococcus aureus Associated
Surgical Site Infections
Mary Nicholson RN, BSN CICThe Christ Hospital
Cincinnati, Ohio
TCH stats
555 bed tertiary care hospital 25,840 admissions/year44 ICU beds; ADC of 36
Services: Cardiac surgery (CVS),
Orthopedic, Oncology, Neurosurgery, OB-Gyn, Renal Transplant, Medicine, and Pulmonary
Internal Medicine Residency ProgramUS News and World Report
rankings (2008)Endocrinology (29)Heart & Heart Surgery (26), Neurology & Neurosurgery (34)Respiratory Disorders (38)
Introduction
There are approximately 470,000 cardiovascular surgeries performed annually in the US.
The incidence of surgical site infections (SSI) is generally low at 1% to 8%, with an associated mortality rate of 14-47%
Complications and consequences associated with surgical site infections (SSI) are: Increased morbidity and mortality Prolonged hospitalizations Increased health care costs – sometimes greater than 2.8
times the cost of an uncomplicated postoperative CVS patients
Jakob (2000) demonstrated the frequency of wound infections in CVS patients to be 1.9% to 15% with S aureus infections varying from 12% to 36.9% of the infections.
Coronary Artery Bypass Surgery
Bypass surgery consists of grafting veins or arteries from the aorta (a major artery that carries blood from the heart to the rest of the body) to the coronary artery, bypassing areas that are blocked.
Sternal Wound Infections
Sternal/Leg Wound Infections
Treatment of Sternal Wounds
Medical Therapy: The use of a vacuum-
assisted closure (VAC) device, allows for either sole therapy for sternal wound closure or adjunctive therapy in preparation for muscle flap closure.
The principles of adequate wound debridement, treatment of infection, and closure of dead space still predominate as initial management decisions in treating sternal wounds.
Radical Sternectomy With significant
osteomyelitis of the sternum, fixing the sternum is impossible.
The persistent infection results in a recurring sinus tracts and infectious drainage unless the infected bone and hardware are removed.
Rectus Abdominus Flap
Rectus abdominus muscle and 8th intercostal perforator for coverage of sternal defects
Staphylococcus aureus
The most common pathogen causing SSI is Staphylococcus aureus (S. aureus).
S.aureus is endogenous to the human body with the primary site of colonization the anterior nares (Herwaldt 2003)
Weinstein (1959) noted there was a correlation between S.aureus and all types of SSI.
Kluytmans et al (1996) showed in a study that preoperative nasal carriage was the most important risk factor of surgical infections.
Studies have determined ~ 25-30% of the population may be colonized at any given time with S.aureus
Carriers of S aureus are 2-9 times more likely as non- carriers to have SSI
Jakob also demonstrated 28.1% of his CVS patients showed nasal colonization of S aureus preoperatively with 16% developing SSI, whereas the 71% patients with normal flora in their nares only 7.7% developed an SSI.
Ursy et al (2002) found in a CVS study over a 2 year period the SSI rate was 2.6% with S aureus accounting for 79.4% of that grouping
Mupirocin Usage
Perl, et. al, (2002) conducted a randomized double blinded placebo controlled trial to determine whether intranasal mupirocin reduces the rate of S. aureus infections at surgical sites and prevents other nosocomial infections
4030 patients were enrolled who underwent CVS, general surgery, neurosurgery, gynecologic procedures.
891 patients who had S aureus in their anterior nares, 444 received mupirocin and 447 placebo
Among the patients with S aureus nasal carriage 4.0% who received mupirocin had nosocomial
S.aureus infections as compared with the 7.7% who received placebo
Concluded mupirocin significantly reduced the rate of nosocomial infections due to S aureus, specifically among patients with nasal carriage of S aureus, the group expected to be at increased risk
CVS TCH STATS
At this hospital S.aureus accounted for 80% of the SSI in CVS population
During the preceding 16 month period (Jan 02 –April 03) the overall CVS SSI rate was 1.89% (18 infs/per 954 procedures performed)
MRSA non-surgical isolates occurred in ~ 11 patients each year
Study reviews found using prophylactic mupirocin ointment applied to the nares decreased the incidence of S. aureus associated nosocomial infections
2002 Quality control hospital statistics found the average cost to treat a deep sternal infection was $ 42,700.00
Study Purpose
The objective of this study was to show that, with performing prescreening nasal cultures and with both pre- and postoperative treatment with mupirocin, there would be a significant decreases in SSI in CVS patients.
Cost Impact
The cost impact of starting the project was estimated to be ~ $45,000 for approximately 900 patients $12 for the S aureus screening nasal culture ~ $38 for a 1 week supply of mupirocin
Based upon the 2002 costs of a deep sternal infection, if one infection was prevented it would pay for the cost of the project.
Culture Protocol
All patient’s nares were cultured preoperatively using the Oxoid Penicillin Binding Protein Latex agglutination test before the patient skin was prepped in the operating room. This screening test selects for S.aureus and
reports both methicillin sensitive and resistant strains
After the nasal culture was obtained, each patient received an intranasal mupirocin application to each nares
The mupirocin application was continued every 12 hours until the culture results were available. If the culture returned positive for S.
aureus, mupirocin was continued for a total of 14 doses
If the culture returned negative, mupirocin was stopped
CVS Procedures April 2003 - September 2004
687
268
61 34 14 130
100
200
300
400
500
600
700
800
CABG +/- IMA Heart valve IMA CABG + Heartvalve
Vascular Other openheart
Total
1077 patients were studied
Nasal screening results
April 2003 – September 2004
1077
855
222
30
0
250
500
750
1000
1250
Total cultured No S.aureusisolated
S aureus isolated MRSA
Approximately, 22% of the patients were identified as nasal carriers
Infections: Pre and Post Mupirocin
0
5
10
15
20
Total Infections S. aureus Infections S.aureus Deep
Pre- mupirocin Post- mupirocin
SSI Results
33% reduction in overall infections 75% decrease in S. aureus associated
infections (p < 0.006) 90% decrease in deep sternal S.aureus
infections ( p<0.0087)
Elimination of MRSA non-surgical isolates in this population and no incidences of MRSA pneumonia, UTIs or bacteremias
Cost Impact of Deep SSI Pre vs. Post Mupirocin
$513,192
$172,300
$0
$100,000
$200,000
$300,000
$400,000
$500,000
$600,000
Pre mupirocin costs Post mupirocin costs
Post mupirocin costs include the $42k start up costs
Total Joint Surgery Patients
Total Joint Prosthesis
Complications
Second to loosening of the prosthesis, infection is the most common complication of orthopedic implant procedures
Gram positive organisms such as S aureus and Coagulase negative staphylococcus are the predominant organisms in prosthetic joint infections and have occurred at a rate of 0.6 – 2.0% per 100 procedures
Infection Pathways
Introduction of microorganisms during the operative procedure, contiguous spread of post-op wound infection or colonization by hematogenous seeding
The freshly implanted biomaterial is highly susceptible to infection – colonization by even small numbers of bacteria can lead to joint sepsis
During the early post-op period, when superficial infections can develop, the fascial layers have not healed and the deep periprosthetic tissue is not protected by usual physical barriers
Any factor that delays wound healing increases the risk such as: ischemic necrosis, hematoma, wound sepsis or suture abscesses
Treatment Options
Joint irrigation with antibiotics Antibiotic therapy without removal of prosthesis 2 stage implant exchange
Prosthesis removal (infected bone, soft tissue and joint linings- called a synovectomy)
Followed by irrigation and implantation of an antibiotic implanted spacer
Treated with 6-8 week course of antibiotics Once infection is cleared, joint is re-implanted
Arthrodesis- the surgical immobilization of a joint until the bone has healed
Antibiotic Impregnated Joint
TCH Ortho Stats
At TCH over 500 total joint surgeries are performed each year
The associated SSI rate had averaged 0.86% per 100 procedures over the previous 2 year period. S. aureus had accounted for 50% of the SSIs SSI rate 2002 = 1.2% SSI rate 2003 = 0.6%
Hospital Stats
In 2004, there was an increase in total joint SSIs with an associated rate of 1.49% (8/453).
Upon further investigation 5/8 of the SSI were caused by S.aureus (with
3/5 isolates were MRSA) The patients and OR team underwent nasal
cultures to rule out S. aureus nasal colonization 4 patients and 1 OR team member was
identified as S. aureus nasal carriers
All S. aureus isolates were sent to the Ohio Department of Health for DNA pulse field gel electrophoresis typing (PFGE).
This included 5 patients and 1 OR team member’s nasal isolate Six (6) different strains of S. aureus were
identified None of the strains were linked
epidemiologically One patient’s daughter was also
hospitalized with MRSA sepsis and both patient and daughter shared the same strain of MRSA
Protocol
Beginning in December 2004, all total joint patients when reporting for Pre Admission Testing (PAT) Nasal cultures were obtained to rule out S. aureus Cultures are sent to LabOne of Ohio using the
Oxoid penicillin binding protein Latex agglutination test
Culture results would generally be available within 48 hours and before patient was admitted to hospital for surgery
In those cases where cultures had not been collected PTA, SDS are to send a nasal screening culture and begin intranasal mupirocin before surgery
Treatment of Carriers
S.aureus sensitive carriers To receive intranasal mupirocin BID for 7 days IV cephazolin or clindamycin is to be
administered as the pre-operative surgical antimicrobial
Mupirocin is to be continued during hospitalization if not completed pre-operatively
Follow-up culture to be obtained in surgeon’s office
Treatment of Carriers
Methicillin resistant carriers To receive intranasal mupirocin BID for 7 days IV vancomycin is administered as the pre-
operative surgical antimicrobial Patients are instructed to shower with CHG soap Patients are placed into Contact isolation upon
admission to the hospital and continued until culture negative
Mupirocin is continued during hospitalization if not completed pre-operatively
Follow-up culture is obtained in surgeon office
Total Joint ProceduresDec 04 - Dec 2005
Figure 1
7
187
229
0
50
100
150
200
250
THR TKR Shoulder
total
Nasal Culture Results (Dec 04 – Dec 05)
435
316
99
20
050
100150200250300350400450500
Total cultured No Staph aureus S. aureus sensitive MRSA
27% of patients were identified as S aureus carriers at the time of PAT
Findings
27.3% (119/435) of total joint procedure patients were identified as S aureus nasal carriers at the time of pre-admission testing. 16.8% (20/119) of S aureus nasal isolates were MRSA strains.
Zero (0) deep infections occurred during the post mupirocin treatment study period. There was one superficial SSI. There were no deep infections associated with S. aureus.
The SSI rate post mupirocin, was 0.19% (1 infection / 534 procedures). There was an 82% reduction in overall SSIs in historical group (16/1467) to the treated group (p < 0.03).
Infections Pre-mupirocin and Post-mupirocin
16
11
5
9
1 0 1 1
0
4
8
12
16
20
Total infections Deep infections Superficial Total S.aureus
Pre mupirocin Post mupirocin
Pre-op nasal screening results
CVS screening results thru June 08
3933
3081
697
148
0
500
1000
1500
2000
2500
3000
3500
4000
4500
Total no SAS SAS MRSA
Total Joint screening results
Dec 04- June 08
2614
1973
523
980
500
1000
1500
2000
2500
3000
Total No SAS SAS MRSA
Dec 04- June 08
Orthopedic spinal procedures
Jan 07 - June 08
1069
220
36
813
-100
100
300
500
700
900
1100
1300
total No SAS SAS MRSA
Jan 07 - June 08
Pre-op nasal screening impact on SSI
Service Total screened Reductions in SA/MRSA SSI
CVS 3933 90%
Total Joints 2614 75%
Spinal 1069 70%
Application of project and future directions
Pre-operative nasal screening may be applied to other services if S. aureus is a frequent source of SSIs
To be successful, efforts should be coordinated with surgeon offices, microbiology labs and hospitals
Obtaining a culture pre-operatively, eliminates the need to prophylactically treat all patients with a 7 day course of mupirocin; and should reduce the risks of drug resistance
Targeting vancomycin usage for MRSA carriers should minimize the risks of drug resistance
MRSA stats at TCH
MRSA surveillance at TCH
MRSA CASES TRACKED/Healthcare Associated
362 405488 503
639
899 8911039
28 22 25 30 21 21 21 36
0
200
400
600
800
1000
1200
2000 2001 2002 2003 2004 2005 2006 2007
YEAR
# C
ASES
Admissions Nosoc Inf
Patients identified with MRSA – are placed in Contact isolation and records are “flagged”; so that when readmitted - placed in isolation until cultures return negative
Recommendation from ICC
Continue pre-operative nasal screening for SAS/MRSA colonization
Expand the pre-op screening to include patients with other implantable devices (e.g. vascular grafts, ICD, etc).
Support the initiation of a surveillance study in MICU to determine baseline prevalence rate of MRSA nasal carriage (medical residents)
Continue to place all MRSA patients in Contact isolation until follow-up cultures return negative
Do not recommend MRSA hospital wide surveillance at this time.
Awards and Publication
2004 Sodexho Health Care Services : Honorable Mention: Spirit of Excellence Award for Quality
Nicholson, MR and Huesman LA. Controlling the usage of intranasal mupirocin does impact the rate of Staphylococcus aureus deep sternal wound infections in cardiac surgery patients. Am J Infect Control 2006; 34(1):44-48.
Midwest Nursing Research Society Annual Meeting, Milwaukee April 2006 Poster presentation: Limiting the Usage of Intranasal Mupirocin Does Impact the Rate of Staphylococcus aureus Deep Sternal Wound Infections
APIC Blue Ribbon Abstract Award 2006 – Tampa, June 2006: Poster Presentation: Pre-operative Staphylococcus aureus Nasal Screening does Reduce Total Joint Surgical Site Infections
American College of of Orthopedic Surgeons – Poster presentation- February 2007: Screening for S. aureus does Reduce Total joint SSI.
Anthem’s Hospital Quality Meritorious Award March 2007
Poster and Oral presentations at National Orthopedic Nursing Association May 2007 and 2008.
Our CVS Team
Our Ortho Team
Questions??
Thank you!