Line associated infections and
bacteraemia
Dr. Brian O’Connell
Adapted from Bone et al. Chest 1992; 101: 1644-55
Gram negative cell wall
Diagram of a Gram-positive bacterial cell-wall
Microbial triggers of sepsis
• Bacteraemia/fungaemia
– Positive blood cultures are more common the more severe
the disease
• More likely to have positive blood cultures in patients with septic
shock
• Severe local infections associated with greater mortality
• Endotoxaemia – lipopolysaccharide
• Other bacterial toxins
– Bacterial superantigens (e.g. TSST-1, streptococcal
pyrogenic exotoxins)
Diagnosis of Sepsis
• No bedside or laboratory test provides a definitive
diagnosis
• Clinical evidence of SIRS (tachycardia, tachypnea,
leucocytosis, fever) with altered mental status,
hyperbilirubinaemia, acidosis, thrombocytopenia
• Non-infective causes include:
– Burns, pancreatitis, trauma, adrenal insufficiency, malignant
hyperthermia, heat-stroke, hypersensitivity reactions)
Identifying Acute Organ Dysfunction
as a Marker of Severe Sepsis
Altered
Consciousness
Confusion
Psychosis
Tachycardia
Hypotension
 CVP
 PAOP
Tachypnea
PaO2 <70 mm Hg
SaO2 <90%
PaO2/FiO2 300
Oliguria
Anuria
 Creatinine
Jaundice
 Enzymes
 Albumin
 PT
 Platelets
 PT/APTT
 Protein C
 D-dimer
Bacteraemia/Blood-stream Infection
(BSI)
• Primary
• cause majority of hospital-acquired BSI (64%)
• most are due to infected intravascular catheters
• remainder have bacteraemia with no identifiable source
• Secondary
• Secondary infections are related to severe infections at
other sites, such as the urinary tract, lung, postoperative
wounds, and skin.
• Cause the majority of community-acquired BSI
Patterns of bacteraemia
3 patterns of bacteraemia
1.
Transient
– Lasts minutes to hours
– Instrumentation of contaminated mucosal surface
• Tooth brushing, dental procedures, cystoscopy
– manipulation of infected tissue
2.
Intermittent
• Usually from un-drained infection
3.
Continuous
– Usually from an endovascular infection
• Endocarditis, infected aneurysm,
Diagnosis of bacteraemia
• Blood culture
– Take two sets from different sites
• Should be performed on all hospitalised patients with
fever (≥38ºC) combined with leucocytosis or leucopaenia
before the use of parenteral or systemic antimicrobial
therapy
• Systemic and localized infections including suspected
acute sepsis, meningitis, osteomyelitis, arthritis, acute
untreated bacterial pneumonia, or fever of unknown
origin in which abscess or other bacterial infection is
suspected or possible
Taking a blood culture from a
central line
Taking a blood culture from a
Peripheral vein
Blood cultures
Take at least 10 ml per set
• What are the most common organisms
recovered from blood?
Different groups of patients
Traditional divisions : 2 broad groups
hospital acquired
community acquired
New divisions: 3 groups
Hospital acquired
Health-care association
Non health-care association /
Unknown
Definitions
Hospital acquired (HA):
isolate recovered from inpatient > 48 h in hospital
Health care associated (HCA):
isolate recovered from patient with one of the following risk factors
•
inpatient in SJH in previous 90 days
•
outpatient in SJH in previous 30 days
•
referred or transferred from another hospital
•
resident in nursing home
Non Hospital or Healthcare associated (NHCA):
isolate from patient not defined as HA or HCA
Top 5 Bacteraemia isolates in SJH
during 2006
HA
n = 658
CNS
S. aureus
315 (48%)
78 (12%)
HCA
n = 279
CNS
E. coli
122 (44%)
35 (13%)
24 (9%)
NHCA
n = 274
CNS
E. coli
39 (14%)
E. coli
60 (9%)
S. aureus
E. faecium
30 (5%)
S. pneumoniae 17 (6%)
S. pneumoniae 11 (4%)
E. faecalis
22 (3%)
S. maltophilia
BHS Gp.A
7 (3%)
S. aureus
142 (52%)
1 8 (7%)
7 (3%)
Micro-organisms causing bacteraemia
• Overall change from predominantly Gram-negative
infection to Gram-positive infection
%
Single organism bacteraemias in EORTC
trials of febrile neutropenia
20
18
16
14
12
10
8
6
4
2
0
Gram (-)
Gram (+)
I
II
III
IV
V
VIII
IX
X
XIV
(1973- (1978- (1980- (1983- (1986- (1988- (1991- (1993- (199778)
80)
83)
86)
88)
90)
92)
94)
00)
EORTC Trials
What are the common sources of bloodstream infection?
• Hospital-acquired
– Central line
– Urinary tract
– Intra-abdominal
• Community-acquired
– Urinary tract
– Intra-abdominal
– Respiratory tract
Management
1.
Antimicrobial therapy
–
2.
Early appropriate antimicrobial therapy improves survival
Surgical drainage
–
3.
4.
5.
Important to look for and drain sources of infection
IV- fluids, blood transfusion, pressors
Nutrition
Other possible therapies
–
–
–
–
Steroids
vasopressin
Anti-inflammatory drugs
Anticoagulants
Empiric antimicrobial therapy
• choice depends upon institutional
spectrum of infections, susceptibility
pattern of infecting micro-organisms and
individual clinical situation
Catheter-related infections
• Intravascular catheters are indispensable in modernday medical practice
• Infections associated with intravascular catheters are a
major cause of morbidity & mortality
Infectious complications of central venous
catheters (CVCs)
• Local site infection
• Catheter-related blood stream infection (CRBSI)
• Septic thrombophlebitis
– Endocarditis
– Metastatic infection – e.g. endocarditis, lung abscess, brain abscess,
osteomyelitis & endopthalmitis
Appearance of a central venous catheter associated with bacteraemia.
Note the minimal surrounding erythema and purulence at the insertion site
Incidence of catheter-related infection
varies:• Type of catheter - non-tunnelled vs. tunnelled
• Site of catheter – int. jugular > subclavian
• Number of catheter days
• Frequency of catheter manipulation
• Setting of catheter placement i.e. emergency/elective
Incidence of catheter-related infection
varies:
• Hospital size
• Hospital service/unit
• Patient-related factors e.g. underlying disease and acuity of
illness
Pathogenesis of catheter-related blood-stream infection
Scanning electron micrograph of a Staphylococcus biofilm.
Emerging Infectious Diseases 2001; 7: 277-281
Epidemiology
• In the U.S., 15 million catheter days occur in ICUs each
year
• Average rate of catheter associated bacteraemias is 5.2
per 1,000 catheter days
• So, approximately 78,000 catheter associated infections occur in
ICUs in the US each year
• 250,000 cases annually if entire hospitals assessed rather than
exclusively ICUs
Consequences
• Significant increase in patient morbidity & mortality
• Significant increase in hospital costs
• Significant increase in duration of hospitalisation
Morbidity & Mortality
Meta-analysis of 2573 CRBSIs
• Case fatality rate – 14%
• Directly attributable to CVC – 19%
• Mortality rate highest for S. aureus bacteraemia – 8.2% overall
Cost
• In ICU studies, cost per infection is an estimated
$34,500 - $56,000
• Annual cost of caring for patients with CRBSIs
estimated at up to $2.3 billion
Common pathogens isolated in CRBSIs
Pathogen
1986 – 1989 (%)
1992 – 1999 (%)
Coagulase negative
Staphylococci
27
37
Staphylococcus aureus
16
13
(>50% MRSA isolated)
Enterococcus spp.
8
(0.5% VRE)
13
(25.9% VRE)
Gram-negative rods
E.coli
Enterobacteraciae
P. aeruginosa
K. pneumoniae
19
6
5
4
4
14
2
5
4
3
Candida spp.
8
8
Catheter-Related Blood stream infection
(CRBSI)
Definition
Essential Criteria:
Peripheral blood culture positive
Clinical signs and symptoms of infection
(Temp>=38ºC or rigors/chills or hypotension)
No other obvious source of sepsis
And one of the following:
1. 15 CFU on line tip
2. > 2 h differential time to positivity
(Central vs. Peripheral)
Guidelines for prevention of Intra-vascular Catheter Related infections
MMWR August 9,2002/Vol.51/No.RR-10
Management of Catheter-related blood-stream infection
Tunnelled CVC-related blood stream infection
Complicated infection
Tunnel infection
or port abscess
Remove CVC/ID &
treat with antibiotics
for10–14 days
Septic thrombosis,
endocarditis,
osteomyelitis
Remove CVC/ID & treat
with antibiotics for 4 – 6
weeks, 6 – 8 weeks for
osteomyelitis
Tunnelled CVC-related blood stream infection
Uncomplicated infection
Coagulase negative
Staphylococcus
•May retain CVC & use
systemic antibiotic for 7 days
plus antibiotic lock therapy
for 10 – 14 days
•Remove CVC if there is
clinical deterioration or
persisting or relapsing
bacteraemia
S. aureus
•Remove CVC & use systemic
antibiotic for 14 days if TOE –ve
•For CVC salvage, if TOE –ve use
systemic & antibiotic lock therapy for
14 days
•Remove CVC if there is clinical
deterioration, persisting or relapsing
bacteraemia
Tunnelled CVC-related blood stream infection
Uncomplicated infection
Gram-negative bacilli
•Remove CCV & treat from 10 –14
days
•For CVC salvage use systemic &
antimicrobial lock therapy for 14
days
•If no response, remove CVC &
treat with systemic antibiotics for
10 – 14 days
Candida spp.
•Remove CVC & treat with
antifungal therapy for 14 days after
last positive culture
Strategies for prevention
Quality assurance and continuing education
•
•
•
•
Standardisation of aseptic care
Staff training in CVC insertion & maintenance
Specialised “IV teams”
Appropriate staffing levels
•
•
•
•
•
site of catheter insertion
choice of catheter material
hand hygiene
aseptic technique
catheter site dressing regimens
Audit: