Transcript Document

Changing Epidemiology of
Staphylococcal Infections
 1st report 1940s
 penicillinase-producing strains of
Staphylococcus
 Hospital setting
 High risk patient (IVDU, chronic indwelling
catheter)
 Upward trend in the prevalence of
community-acquired MRSA strains in lowrisk patients
 community-acquired MRSA skin and soft-
tissue infections
increased 6.84 fold
 from 24.0 cases per 100,000 people in 2000 to
164.2 cases per 100,000 people in 2005
Arch Intern Med. 2007;167:1026-33.
 similar trends of increasing prevalences of
community-acquired MRSA, with the conclusions
being that this is now the predominant organism
in skin and soft-tissue infections
N Engl J Med. 2005;352:1436-44.
 there is currently no systematic
surveillance for antibiotic-resistant
organisms in the community setting, the
true prevalence of this organism is difficult
to ascertain
Resistant Surgical Site Infections
 Fulkerson et al.
 The susceptibilities of Staphylococcus
epidermidis and Staphylococcus aureus to
cefazolin were only 44% and 74%
 These Staphylococcus epidermidis and
Staphylococcus aureus infections were 100%
sensitive to vancomycin
J Bone Joint Surg Am. 2006;88:1231-7.
 Phillips et al.
 1987~2001, 5947 hip replacements & 4788
knee replacements
 Infection rate 0.57% & 0.86 %
 Prophylaxis : cefuroxime (resistant rate 29%)
 MRSA (3/3)
 Pseudomonas aeruginosa (3/3)
 coagulase-negative Staphylococcus (11/27)
J Bone Joint Surg Br. 2006;88:943-8.
 The recommended prophylactic antibiotic
agents, cefazolin and cefuroxime, lacked
activity against MRSA and MRSE.
 The prevalences of these organisms as
causes of infections are increasing
according to the antibiogram data of
numerous hospitals
Prophylactic Antibiotics in Institutions
with High Bacterial Resistance
 Use Vancomycin as prophylactic A/B (alone
or combination)  controversial
 Recommendations for the use of intravenous
antibiotic prophylaxis in primary total joint
arthroplasty. AAOS.2004
 Clindamycin or vancomycin may be used for
patients with a confirmed b-lactam allergy
 Vancomycin may be used in patients with known
colonization with MRSA or in facilities with recent
MRSA outbreaks
 The use of prophylactic antibiotics in
orthopaedic medicine and the emergence
of vancomycin-resistant bacteria. AAOS.
2002
 Vancomycin may be appropriate as a
prophylactic antimicrobial for patients
undergoing joint replacement at institutions
that have identified a significant prevalence
(e.g., >10-20 percent) of MRSA and MRSE
among orthopaedic patients
 The Hospital Infection Control Practices
Advisory Committee guideline
 a high frequency of MRSA infection at an
institution should influence the use of
vancomycin for prophylaxis
Vancomycin
 A large tricyclic glycopeptide molecule
 Bactericidal action is a result of the
inhibition of bacterial cell wall synthesis
 Active against most gram-positive
organisms
 Staphylococcus aureus, Staphylococcus
epidermidis, streptococci, enterococci, and
Clostridium
 Reaches high concentrations in bone,
synovial tissue, and muscle within minutes
 Adverse reactions
 Red man syndrome (5~13%)
 a pruritic, erythematous rash
 occasionally accompanied by hypotension
 its rapid infusion and histamine release
 Nephrotoxicity, ototoxicity < 1%
 Reversible neutropenia
 Drug fever Daptomycin should be considered as an alternative
 For prophylaxis, its infusion should begin
one to two hours before initiation of the
operation within one hour for cefazolin
 repeat administration is recommended in six to
twelve hours
 Dose: 10~15 mg/kg
 Cardiac surgery
 Prophylaxis with Cefazolin vs. Vancomycin
 Infection rate: no difference
 Difference in the types of surgical site infection
 The choice of prophylaxis changed the flora of
infections but not the rate of infections
Clin Infect Dis. 2004;38:1706-15.
 Ritter et al. Orthopedics. 1989;12:1333-6.
 A single dose of vancomycin and gentamicin
preoperatively  safe and effective
 no early infections in this case series
 Savarese et al.
Chir Organi Mov. 1999;84:247-51.
 1 g of vancomycin given one hour before and
six hours after the operation
Vancomycin resistance
 The first staphylococci with reduced
susceptibility to vancomycin
 Vancomycin-intermediate Staphylococcus
aureus
Morb Mortal Wkly Rep. 1997;46:624-6.
 Vancomycin resistant Staphylococcus
aureus
 Occur infrequently
Morb Mortal Wkly Rep. 2002;51:565-7.
 Newer A/B
 linezolid, quinupristin/dalfopristin, daptomycin,
and tigecycline
Role of Screening for MethicillinResistant Staphylococcus aureus
 Patients may be screened to determine
whether they are colonized with drugresistant bacteria
 Robicsek et al.
Ann Intern Med. 2008;148:409-18
 reported a reduction by more than half in health-
care-associated MRSA
 Perl et al.
N Engl J Med. 2002;346:1871-7.
 No significant reduction of surgical site
infections by Staphylococcus aureus
 nasal mupirocin did reduce the rate of
infections among patients who were previously
Staphylococcus aureus carriers
 Kalmeijer et al.
Clin Infect Dis. 2002;35:353-8.
 Five (1.6%) of 315 cases in the mupirocin
group compared with eight (2.7%) of 299 in
the placebo group, which was not a significant
difference
 on preoperative nasal decolonization in
patients undergoing orthopaedic joint
replacement procedures
Clin Orthop Relat Res. 2008;466:1349-55.
Clin Orthop Relat Res. 2008;466:1343-8
Local Antibiotic Prophylaxis
 Aminioglycosides
 cause bacterial cell death by an intracellular
mechanism, binding to a 30S subunit of the
ribosome and thereby inhibiting protein
synthesis
 Buchholz et al.
 addition of aminoglycoside antibiotics to
Palacos bone cement in a large series of
exchange arthroplasties
Bone Joint Surg Br. 1981;63:342-53.
 Josefsson et al.
 a series of 1688 consecutive total hip
arthroplasties followed for ten years
 it might be beneficial to use parenteral antibiotics
and antibiotic bone cement concurrently
 FDA
Clin Orthop Relat Res. 1981;159:194-200.
Clin Orthop Relat Res. 1990;253:173-8.
 premixed antibiotic bone cement for prophylaxis in
a second-stage re-implantation
 but not as prophylaxis in routine primary
arthroplasties
Overview
 Low prevalence of surgical site infections
associated with hip and knee arthroplasty
 difficult to study
 Reduction in infections
 Measures related to operative technique
 Operating-room environment
 For the last three decades, the
cephalosporins (cefazolin and cefuroxime)
have been the preferred antimicrobials
 Increasing rates of community-acquired
infections
 cefazolin or cefuroxime alone might not be the
appropriate prophylaxis in all surgical settings
 Staphylococcus aureus resistance to cefazolin is
50%
 Staphylococcus epidermidis resistance to
cefazolin is 70%
 Vancomycin along with Cefazolin
Thanks for your attention