MICROBIOLOGY FOR
FOUNDATION YEAR 1
Dr Paul Russell
ST4 Medical Microbiology and
Virology
Introduction
This presentation covers some generic
principles when discussing patients with
microbiology. Some antibiotic guidelines
and ward rounds are specific to
Southampton University Hospitals Trust. In
other hospitals always refer to the local
guidelines or national guidelines where
indicated.
PART ONE
How to use the microbiology
department
The microbiology department
Handles over 500,000 specimens annually
~80 Scientific staff
Admin and support staff
6 consultant microbiogists
1 consultant virologist
3 microbiology trainees (may decrease to 2)
Infection Control
Lyme Reference Unit (National Reference Lab)
Contacting microbiology
0900-1700 Monday-Friday
Extension 6408
Out of hours
– Via switchboard
What happens when you ring...
Office takes note of your call
E-mailed to relevant consultant or StR microbiology.
Consultant enquiries are put directly through
There is now a “triage” where calls from consultants and
registrars are dealt with first.
Important or complex calls should be made by a
registrar (ST3 or above) or consultant
Time to reply will depend on workload and complexity
– Avoid 11.00-13.00 as bench round is conducted and results are
authorised
– Can get busy after 16.30
Before you ring......
Get to know when the ward rounds are
conducted
Try and be around
Refer via the ward pharmacist
Read the notes for previous
reviews/discussion
Do the available guidelines cover your
enquiry
Ward Rounds
Mon
14.00 PICU/GICU (Dr Ann Pallet)
14.00 Haematology (Dr Tatshing Yam)
15.00 CTITU (Dr Tatshing Yam)
Tues
08.30 Oncology MDT (Dr Tatshing Yam)
08.30 Surgery (Dr Adriana Basarab)
14.00 Cardiothoracic (Dr Tatshing Yam)
15.00 T+O (Dr Graeme Jones)
Wed
09.00
10.30
13.30
14.00
Paeds/PICU + 12.00 NNU (Dr Ann Pallet)
Neurology/neurosurgery (Dr Julian Sutton/Dr Helmut Schuster)
GICU (Dr Ann Pallet)
Medicine (Dr Julian Sutton/Dr Helmut Schuster)
Thurs 13.00 Haematology MDT (Dr Tatshing Yam)
15.00 Cardiothoracic (Dr Tatshing Yam)
Fri
09.00 Surgery (Dr Adriana Basarab)
09.00 Medicine (Dr Julian Sutton/Dr Helmut Schuster)
15.00 Neurology/neurosurgery (Dr Julian Sutton/Dr Helmut Schuster)
Before you ring.....
EXAMINE THE PATIENT!!!!
Initial admission – when, why
Progress since admission
Current condition and your concerns
– Resps, HR, BP, Sats, pO2, WCC, CRP, lactate and
trends
– How do they relate to the patient
– Consider the “numbers” and the patient holistically
Current antibiotics
– Start/stop dates, efficacy, reason for antibiotics,
ALLERGIES
Current investigations
– What has been done and those pending
Before you ring....
CHECK THE ANTIBIOTIC GUIDELINES
AND THEN DISCUSS IT WITH A
SENIOR MEMBER OF YOUR TEAM
A vast majority of problems can be sorted at reg
or consultant level
Out of hours – Consultant
microbiologist
On call covers 1700-0900 following morning
Contactable via switchboard
Off site
Weekends
– Saturday 0900-Monday 0900
– On-site during the day (usually 10.00-15.00 but variable)
All out of hours calls must be discussed with the
consultant prior to calling microbiology
The microbiology consultant will often ask your consultant
to contact microbiology directly
Out of hours – Biomedical Scientist
Contactable via switch
Technical enquiries and processing urgent specimens
On-call from 1700 weekdays
– Laboratory staffed until 20.00
– Off site and called in
On call throughout weekend
– Laboratory staffed 08.30-17.30
– Off site and called in
No category 3 work can be done once staff are off site
– E.g. Acid fast staining for TB
– NOTE THAT THIS IS A HEALTH AND SAFETY
REQUIREMENT
Enquiries regarding sampling
Common enquiries - Sampling
URGENT
– Only sterile site site specimens will be processed
urgently
i.e. A Gram stain will be done and culture set up
– CSF, vitreous humour, contact lens/cornea, joint fluid,
CAPD fluid, ascitic/pleural tap
– Blood
We do not do direct Gram stains on blood smears
Malaria is requested seperately and via haematology
Urines/faeces will not be processed urgently
– DO NOT REQUEST THEM
OOH – contact the on-call scientist ONCE the
sample has been taken
Leave an appropriate bleep/contact number
Call the porters to deliver the sample to
pathology
Common enquiries - Sampling
“What bottle do I use?”
– Ask a senior
– Refer to the pathology handbook (available on the SUHTranet)
When taking swabs
– Ensure you are requesting the correct investigation
MRSA screen vs MC+S
– Superficial swabs are generally unhelpful
Deeper swabs
– If there is pus then send a sample of pus!
The lab can do more with it plus it can be stored for a short time for
further tests
– Viral/chlamydial vs bacterial
Use the correct swab
There are specific viral swabs (usually green top)
Can use bacterial swab but break swab into viral transport medium
Common enquiries - Sampling
Blood cultures
– Good skin preparation
– Correct volume – 8-10mL per bottle
– If struggling then use paediatric bottle
Not optimal
Common enquiries - Sampling
CSF
– Commonly asked for MC+S, fungal culture,
TB culture, Cryptococcal antigen, bacterial
and viral PCR......
Common enquiries - sampling
CSF
– Approx 200μL for MC+S
– 200μL for 3 PCR tests
Can be diluted but loss of sensitivity
Get history especially of risk factors
– Prioritise
Common enquiries - Sampling
Unlabelled/incorrectly labelled specimens will be
rejected
Caution with abbreviations – the scientific staff
are not clinical
– E.g. C?C
Urine samples
– Rejected if no appropriate clinical details
Including “Dip positive”
– If a UTI is suspected then say so.
– If septic then say so
IMPORTANT
If TB is a differential diagnosis
ALL SAMPLES MUST BE LABELLED AS SUCH
Irrespective whether that particular sample needs
TB culture or AFB staining
Specify any recent foreign travel when sending
samples from unwell admissions
– ALWAYS do a malaria screen if travelled through or
from malaria area irrespective of taking prophylaxis
Results
Streptococcus pneumoniae
“Pneumococcus”
Gram positive cocci looking like
Staphylococci
Gram positive cocci looking like
Streptococci
Gram positive bacilli
Gram negative bacilli
Gram negative cocci
Gram +ve Cocci (spherical)
Staphylococci
Streptococci
Enterococci
Peptococci/Peptostreptococci*
Gram -ve Cocci
Neisseria meningitidis
Neisseria gonorrhoea
Moraxella catarrhalis
Acinetobacter (coccobacillus)
Gram +ve Rods
Clostridia*
Corynebacteria (diphtheroids)
Listeria
Bacillus
Gram -ve Rods
Bacteroides*
Lactose-fermenting coliforms
E coli, Klebsiella, Enterobacter
Non lactose-fermenting coliforms
Proteus, Salmonella, Shigella
Pseudomonas
Haemophilus
Helicobacter, Campylobacter
Legionella
*Anaerobes
Sample processing
Gram stain gives limited information
Microscopy
– Cell counts in CSF and urine
– Ova, cysts, parasites in faeces
Culture
Sensitivity
Processing dependent on growth
– Usually 48 hours
Growth on agar
α-Haemolysis
β-Haemolysis
Fermentation reaction
Coagulase testing
Identification
Antibiotic sensitivities
Temperature and CRP
Body Temperature
The normal range for temperature in adult
men and women
– Oral 33.2–38.2 °C
– Rectal 34.4–37.8 °C
– Tympanic 35.4–37.8 °C
– Axillary 35.5–37.0 °C
Circadian rhythm
Varies in menstrual cycle
Pyrexia
Hyperthermia – Loss of thermoregulation
– No role of endogenous pyrogens
– Increased heat production
Exercise
Endocrine – thyrotoxicosis, phaeochromocytoma
Drugs – malignant hyperthermia, neuroleptic malignant syndrome
– Decreased heat loss
Heat stroke
Autonomic dysfunction
Drug induced (atropine)
Occlusive dressings
Severe anaemia
Circulatory failure
Absence of sweat glans
– Hypothalamic disorders
Infection
Trauma
CVA
Drug induced
Neoplastic disease
Pyrexia
Fever (Oral temp >37.7) – Re-setting of the
hypothalamic “thermostat”
– Circadian rhythm maintained
– Triggered via endogenous pyrogens (cytokines)
– Triggers
Microbial agents
Toxins
Microbial breakdown products
Tissue breakdown products
Immune components and cytokines
Drugs (incl. antibiotics)
Tumours
– Take temperature at least 20 minutes following eating,
drinking or smoking
Pyrexia
Causes of fever
– Infection
– Immune disorders
Auto-immune disease
Inflammatory syndromes
– Tissue destruction
Haemolysis
Surgery
Crush injury
Rhabdomyolysis
Ischaemia
–
–
–
–
Transfusion related
Neoplastic disease especially haematological malignancy
Metabolic disturbance e.g. gout, porphyria
Thrombo-embolic events
C-Reactive Protein
Acute phase protein produced by the liver
Raised in
– Infection
– Immune disorders
Auto-immune disease
Inflammatory syndromes
– Tissue destruction
Haemolysis
Pancreatitis
Surgery
Crush injury
Rhabdomyolysis
Ischaemia
–
–
–
–
Transfusion related
Neoplastic disease especially haematological malignancy
Metabolic disturbance e.g. gout, porphyria
Thrombo-embolic events
Any questions?
PART TWO
Antibiotics
Antibiotic Advice – Choice of Agent
Community acquired vs hospital acquired?
Identifiable source?
What infection are we dealing with?
What antibiotics has the patient been exposed to?
Is the patient neutropaenic?
Has the patient got renal or liver failure?
Has the patient got any allergies or on other drugs that may
interact with antibiotic?
Is the patient pregnant?
Age
Local policy
– Resistance patterns
– Strain selection
E.g. Clostridium difficile O27
– Cost
The infection cascade
Community
acquired
pathogens
(MSSA, E coli)
Hospital
acquired
pathogens
(MRSA,
pseudomonas
CoNS)
ITU pathogens
(acinetobacter
ESBLs)
More ITU
pathogens
(Steno, candida)
Carbapenems
Benzyl penicillin +
doxycycline/clarithromycin
OR
Chloramphenicol
Vancomycin +
ciprofloxacin OR
tazocin
Septrin,
Fluconazole /
caspofungin
Guidelines
Antibiotic advice - Duration
Guided by the host-pathogen interaction
Adequate treatment of current infection without predisposing
patient to significant altered colonising flora, cannulaassociated bacteraemia or nosocomial infection
3 days in simple UTI in women
5-7 days for chest infection
7 days for non-severe UTI in men or catheter associated UTI
7-10 days for bacteraemia (14 days minimum for candidaemia
and S aureus)
7-14 days for meningitis (dependent on the causative
organism)
4-6 weeks for “deep” infection e.g. septic arthritis,
endocarditis
Antibiotic advice - Duration
Can I stop antibiotics?
– Easy to start antibiotics
– Microbiology often do not know why
antibiotics were started in the first place
– It is the team that must decide
Look at the patient
Physical condition
Symptomatic improvement
Repeat microbiology/investigations
Inflammatory markers
Maintenance/increase in CRP and/or
temperature despite antibiotics
Look at trends
Look at patient
Investigate
– Emergence of resistant isolate
Repeat septic screen
– Collection/abscess/leak
Imaging
– New infection focus
Cannula/line site
C. difficile diarrhoea/colitis
– New infectious agent
Consider viral
– Non-infectious cause
Having discussed with microbiology
Document discussion in patient notes
Read notes before calling
– If patient reviewed on ward round there will
usually be an entry and plan in the notes
– Look back 3- 4 days!!!
– HICCS entry
Can be viewed on e-quest
Bactericidal versus bacteriostatic
Bactericidal
Beta lactams
Glycopeptides
Fluoroquinolones
Colistin
Daptomycin
Aminoglycosides
Bacteriostatic
Tetracyclines
Clindamycin
Sulfonamides
Trimethoprim
Chloramphenicol
Linezolid
Intermediate
(dose-dependent)
Macrolides
Use bactericidal antibiotics wherever possible for immunocompromised patients
Courtesy of Dr Andrej Trampuz
Broad spectrum agents
Gram –ve/+ve cover
Clarithromycin, Azithromycin
Trimethoprim,
Nitrofurantoin
Amoxicillin
Doxycycline
Ciprofloxacin, Moxifloxacin
Cefalexin, Cefuroxime, Ceftriaxone, Cefotaxime
Amoxicillin, Co-amoxiclav, Piperacillin-tazobactam
Ertapenem, Imipenem, Meropenem
Narrow spectrum
Gram positive agents
Penicillin V/G, Flucloxacillin
Erythromycin,
Clindamycin
Fusidic acid
Rifampicin
Vancomycin, Teicoplanin
Linezolid
Daptomycin
Narrow spectrum
Gram negative agents
Gentamicin, Tobramicin, Amikacin
Colistin
Ceftazidime
Aztreonam
Anti-atypical agents
Doxycycline
Erythromycin, Clarithromycin, Azithromycin
Ciprofloxacin, Moxifloxacin
Broad-spectrum antibiotics: when
are they justified?
Serious or life-threatening infection or
immunocompromised patient
– The ‘need to be right’ is high
Likely or proven polymicrobial infection
Risk of infection with resistant bacteria
– due to recent contact with healthcare environment
– due to recent exposure to antibiotics or failed first-line therapy
Known infection with resistant bacteria
– Current or recent laboratory results
Treatment failure of narrow spectrum agents
Antibiotic spectrum
Anaerobic
Streptococci &
Clostridia
Group A, B, C, G
Gonococcus
Meningococcus
Bacteroides
fragilis
Gram Positive
Staphylococci
Strep
pneumo
Streptococci
EF
R
A
G
R
A
Streptococcus
pneumoniae
Pseudomonas
aeruginosa
Atypicals
Gram Negative
MRSA
MRSA and
Coagulasenegative
Staphylococci
Legionella,
Chlamydia &
Mycoplasma
pneumoniae
Anaerobes
G
Enterococcus
faecalis &
Enterococcus
faecium
R
GC
Men
Resp
Coliforms
Pyo
ESBL
A
G
R
A
G
Respiratory
Gram -ve e.g.
Haemophilus
influenzae &
Moraxella
catarrhalis
Gut bacteria
e.g. E. coli
R
Extendedspectrum betalactamase
producers
Red = Generally Resistant; Amber = Unreliable; Green = Generally Sensitive
Penicillins (ß-lactams)
Antibiotic
Gram Positive
Atypicals
Gram Negative
MRSA
Staph
Strep
pneumo
Streptococci
EF
GC
Men
Resp
Coliforms
Pyo
ESBL
Benzylpenicillin /
Penicillin V
R
R
G
G
R
G
A
A
A
R
R
R
R
Flucloxacillin
R
G
G
G
R
R
R
R
R
R
R
R
R
Amoxicillin
R
R
G
G
G
A
R
A
A
A
R
R
R
Co-amoxiclav
R
G
G
G
G
G
G
G
G
G
R
R
R
R
G
G
G
G
G
G
G
G
G
G
A
R
Ertapenem
R
G
G
G
A
G
G
G
G
G
R
G
R
Imipenem
R
G
G
G
G
G
G
G
G
G
G
G
R
Meropenem
R
G
G
G
A
G
G
G
G
G
G
G
R
Anaerobes
Anti-pseudomonal
Tazocin
Carbapenems
Cephalosporins (ß-lactams)
Antibiotic
Gram Positive
Atypicals
Gram Negative
MRSA
Staph
Strep
pneumo
Streptococci
EF
GC
Men
Resp
Coliforms
Pyo
ESBL
R
G
G
G
R
A
R
R
R
A
R
R
R
R
G
G
G
R
A
R
A
G
G
A
A
A
Ceftriaxone &
Cefotaxime
R
G
G
G
R
A
R
G
G
G
R
R
R
Cefixime
R
R
G
G
R
A
R
A
G
G
R
R
R
R
A
A
A
R
A
R
A
G
G
G
R
R
Anaerobes
1st generation
Cefalexin
2nd generation
Cefuroxime
3rd generation
Antipseudomonal
Ceftazidime
Other cell wall antibiotics
Antibiotic
Gram Positive
Atypicals
Gram Negative
MRSA
Staph
Strep
pneumo
Streptococci
EF
GC
Men
Resp
Coliforms
Pyo
ESBL
Vancomycin &
Teicoplanin
G
G
G
G
G
G
R
R
R
R
R
R
R
Daptomycin
G
G
R*
G
G
G
R
R
R
R
R
R
R
Aztreonam
R
R
R
R
R
R
R
G
G
G
G
R
R
Colisin
R
R
R
R
R
R
R
R
A
G
G
G
R
Anaerobes
Glycopeptides
*Inactive in the lung
Protein synthesis inhibitors 1
Antibiotic
Gram Positive
Atypicals
Gram Negative
MRS
A
Staph
Strep
pneumo
Streptococci
EF
GC
Men
Resp
Coliforms
Pyo
ESBL
G
G
G
A
R
G
A
A
G
A
R
A
G
Erythromycin
R
A
G
A
R
A
R
A
A
R
R
R
G
Clarithromycin
R
G
G
A
R
A
R
A
G
R
R
R
G
Azithromycin
R
G
G
A
R
A
R
A
G
A
R
R
G
Clindamycin
R
G
G
G
R
G
A
R
R
R
R
R
A
Anaerobes
Tetracyclines
Doxycycline
Macrolides/Lincosamid
e
Protein synthesis inhibitors 2
Antibiotic
Gram Positive
Atypicals
Gram Negative
MRSA
Staph
Strep
pneumo
Streptococci
EF
GC
Men
Resp
Coliforms
Pyo
ESBL
R
G
R
R
A
R
R
R
G
G
G
G
R
Sodium fusidate
G
G
A
A
G
G
R
G
R
R
R
R
R
Linezolid
G
G
G
G
G
G
A
R
A
R
R
R
R
Nitrofurantoin*
G
G
G
G
G
R
R
A
R
G
R
G
R
Chloramphenicol
G
G
G
G
A
G
G
G
G
A
R
A
G
Anaerobes
Aminoglycosides
Gentamicin /
Tobramycin /
Amikacin
Miscellaneous
Nucleic acid & RNA / DNA inhibitors
Antibiotic
Gram Positive
Atypicals
Gram Negative
MRSA
Staph
Strep
pneumo
Streptococci
EF
GC
Men
Resp
Coliforms
Pyo
ESBL
Trimethoprim
A
A
A
G
G
R
G
A
A
A
A
A
R
Septrin®
G
G
G
G
G
R
R
A
A
A
A
A
R
G
G
G
G
A
G
R
G
G
R
R
R
G
R
R
R
R
R
G
G
R
R
R
R
R
R
Ciprofloxacin
R
A
A
A
R
R
R
G
G
G
G
A
G
Ofloxacin
R
G
A
A
R
A
A
G
G
G
G
A
G
Moxifloxacin
A
G
G
G
G
G
G
G
G
G
R
A
G
Anaerobes
Anti-folates
Rifamycins
Rifampicin
Nitroimidazole
Metronidazole
Quinolones
HAPPI audit
(Hospital Antibiotic Prudent Prescribing Indicators)
Six indicators of prescribing quality will be
measured:
Drug chart
– 1. Allergy Box completed
– 2. Review or stop date documented on drug chart
Medical notes
– 3. Documented indication or provisional diagnosis (on
start date)
– 4. Guideline antibiotic for indication or documented
valid reason for off-guideline prescribing
– 5. IV duration <48hrs or as per guideline
– 6. Total duration <7 days or as per guideline
HAPPI Indicator 4: Definitions
“Valid reasons” for off-guideline choice of antibiotic
1.
2.
3.
4.
5.
6.
Recommendation by named Micro/ID Dr
Culture and Sensitivity result
Failure* of guideline therapy
Recent prior antimicrobial exposure
Contra-indication to guideline agent
Patient risk factors** for resistant pathogen
*“Failure” of guideline therapy
–
–
No clinical/inflammatory marker improvement after 48 h
Acute septic deterioration on guideline abx
**“Risk factors” for resistant pathogen
–
–
–
Recent or frequent contact with a healthcare environment
Nursing or care home resident
Prior antibiotic exposure
Urinary Tract Infection
Respiratory Tract Infection
Macfarlane JT (1999). Lower respiratory tract infection and pneumonia in the community.
Semin Respir Infect, 14, 151-162
Cellulitis
Diagnosis?
Diagnosis?
Diagnosis?
Diagnosis?
Diagnosis?
Diagnosis?
Diagnosis?
Cellulitis
Can be difficult diagnosis
Usually hot, erythematous, oedema and tender
Systemic
– Pyrexia
– Nausea
– Local lymphadenopathy
Younger patients
– Nearly always offending lesion e.g. bite
Older patients
– Co-morbidities may predispose
– May not cure without treating underlying co-morbidity
Questions?
PART THREE
Antibiotic failure and complex
infection
Why do antibiotics fail?
Time
– Do not work instantly
Especially in chest infection. X-ray changes may lag
– Some effect can be seen over 24-48 hours
Wrong antibiotic
– Wrong choice
– Resistant organism
Inherent
Induced or selected
Non-bacterial infection
Wrong dose
– Ensure flush following IV dosage
Wrong route
Inability to reach site
– Anatomically
Privileged sites e.g. CSF
– Cellular
Privileged intracellular sites e.g. phagolysosome
– Pathological
Why do antibiotics fail?
Source control
– Fluid collection
– Biofilm
Especially on prosthetic material
– Abscess
New source of infection
Compliance
Interaction with other drugs/foods
– E.g. Doxycycline and magnesium preparations
How do you know antibiotic choice is failing?
Difficult
Needs detailed clinical review
– Review patient
Physiological trends
Biochemical and haematological trends
– What is the “known” infection doing
Visually worsening
– E.g. X-ray change, spreading cellulitis
– New focus
Check head, chest and abdomen
– THAT INCLUDES IMAGING!
Skin and soft tissue
Lines
Clostridium difficile
– Also think non-infectious
Cardiac events
Hypoglycaemia
Malignancy
Auto-immune disease
Check microbiology results
Antibiotic failure
Sudden onset changes – seconds-minutes are
unlikely to be infection
Sustained temperature, with worsening
physiology
– Likely antibiotic failure
Temperature spikes but remains stable,
inflammatory markers static and often high
– Likely source control issue
Slow improvement
– Likely host related
Especially bacteriostatic agents in immunosuppressed
Neutropaenic patients may appear to get worse
when neutrophils recover
– Recovery of cytokine response and cell mediated
immunity
Antibiotic failure
Patient improves on antibiotics.
Deteriorates on cessation
– Likely relapse. Restart previous antibiotics,
duration may have been too short
Antibiotic failure - Treatment
Antibiotic change
– Look at guidelines
– Discuss with microbiology
Source control
– Surgery
– Drainage
– Removal of prosthesis/line
If bacteraemic, try and keep line free as long as is
practicable
THERE ARE NO HARD AND FAST
RULES – CLINICAL ACUMEN IS
PARAMOUNT
Deep sited infections - Abscess
Needs drainage
Empirical broad cover then narrow down
with microbiology results
Dependent on site and successful
drainage will need 2-6weeks+ antibiotics
Sinus or fistula formation may complicate
Deep site infections - endocarditis
Infection of the heart valve
National guidelines
Generally gram positive
– Including low virulence skin flora
Β-lactam/glycopeptide +
aminoglycoside/rifamycin
Gram negatives rarer and some unusual
– Chlamydia
– Brucellosis
– Q-fever
4-6 weeks intra-venous treatment dependent on
cause and natural/prosthetic valve
Deep site infection –
osteomyelitis/septic arthritis
Infection of bone
Offending organism may have been present for
years before
Biofilm formation
Debridement/washout
Generally gram positive bacteria
Β-lactam/glycopeptide + rifamycin/fusidate
2 weeks IV antibiotics followed by 4 weeks oral
antibiotics
Prostheses infections difficult to treat and usually
require removal. Replacement must be 2 stage.
Septic Shock
Microbiological emergency
You must be able to recognise
You must be able to manage
Critical Care Protocol:
Early Antibiotic Administration in Septic Shock
Criteria for Severe Sepsis
(see Box 1 overleaf)
Senior Dr Review
Fluid unresponsive?
( 20ml/kg crystalloid or equivalent)
NO
Antibiotics as
per trust pocket
guidelines
YES
1. SEPTIC SHOCK: Hypotensive despite fluid resuscitation with clinical evidence of infection.
2. High risk for requiring vasopressors within 4 hours (if not responsive to treatment below).
TAKE BLOOD CULTURES X 2
and
Give IV Antibiotics Immediately
1ST Line
(Document as per Box 3)
For Continued Antimicrobial Use
Especially MEROPENEM
Single dose Gentamicin
3mg/kg (max 240mg)*
&
Piperacillin / tazobactam 4.5g QDS for 48 hrs
Registrar / Consultant to
Contact Medical Microbiologist
Non-severe Penicillin allergy:
Gentamicin 3mg/Kg stat (max 240mg)*
(see Box 2 overleaf)
+
Meropenem 1gm 8 hourly
2nd Line
See Box 2 paragraph 3
Severe penicillin allergy (anaphylaxis or urticarial reaction on exposure to penicillins or
cephalosporins)
Gentamicin 3mg/Kg (max 240mg)* + Ciprofloxacin 400mg bd iv + Vancomycin IV
+ Metronidazole 500mg iv tds
ADD Vancomycin IV if MRSA risk
+
Caspofungin IV if high risk of invasive fungal infection
*Check Gent level at 12 hours – if <3mg/l and still in septic shock then re-dose at 24 hrs
Guidelines are ONLY for use in patients with Septic
Shock
Box 1: To diagnose Severe Sepsis patients must reach all three of the following criteria. Follow top of guideline overleaf.
1. Known infection or clinical evidence suggestive of infection
2. Meet 2 or more of SIRS criteria?
Tachycardia ≥90
RR> 20 or PaCO2 <4.3
WCC >10 or <4
Temp ≤36 or ≥38
3. Evidence of end organ hypo-perfusion
Systolic BP <90 or MAP <65
Cr >180 or U/O <0.5ml/kg for 2 hours
Lactate >2
Bili > 35, Plt < 100, SpO2 <90%, Acute confusion
If your patients meets all three criteria they have Severe Sepsis.
If they are fluid therapy resistant, then they have Septic Shock
1. Follow lower guideline overleaf.
2. Patient must be reviewed by senior doctor ( ST3 / SpR or above)
Box 2: If patient deemed to be in Septic Shock
1. Take 2 blood cultures
2. Give antibiotics immediately (max 30 minutes post- diagnosis)
3. Inform outreach about patient
4. SpR / >=ST3 / Consultant to contact microbiology after giving 1st dose with the following information:
Temp / WCC / RR / Pulse / Renal Function
History of allergy
History of antibiotics within 1 month (ideally within last year)
Previous micro results (ESBL etc)
Nursing home background
4. Re-discuss with micro (Ext 6408) at 48 hours
Box 3: When patient is given antibiotics for Septic Shock please clearly document:
1. Source of sepsis (if known)
2. Time of diagnosis of SIRS / Severe Sepsis criteria & non response to fluid
3. Time cultures sent
4. Time antibiotics given
5. Time blood taken for gentamicin levels
6. Date and time of discussion with microbiology
Don’t forget that the mortality for Septic Shock increases
dramatically every hour antibiotics are not given
Septic shock
Hit “hard and fast”
Gentamicin + Tazocin
Non-severe penicillin allergy – Gentamicin
+ Meropenem
Life threatening penicillin allergy –
Gentamicin + vancomycin + ciprofloxacin
+ metronidazole
Consider vancomycin where there is risk
of invasive MRSA
REMEMBER – blood cultures
Bacteraemia/meningitis
Meningitis
Cefotaxime 2g 4 hrly IV
– +Aciclovir if considering viral encephalitis
– +Rifampicin if recent travel overseas (anywhere!)
– + Amoxicillin 2g 4hrly IV if pregnant or >50 years old
At risk for Listeria
– Dexamethasone 8mg qds IV 2-4 days started with or
just before first dose of antibiotic especially where
pneumococcal meningitis is suspected and no septic
shock or immunosuppression
Penicillin allergy contact microbiology
Duration dependent on causative pathogen but
course needs to be IV
Necrotising fasciitis
Meleney’s synergistic gangrene
Necrotising fasciitis
Urgent surgical review
TREATMENT IS SURGICAL, ANTIBIOTICS
WILL NOT CURE
Tazocin + Clindamycin (1.2g qds IV) + Stat
gentamicin
Penicillin allergy – Clindamycin +
ciprofloxacin + metronidazole + gentamicin
Questions?