Infectious Diseases in the ICU – Antibiotics

Investigation and Diagnostics of Severe Infections

Posted by Kai Knudsen, Senior Physician in Anesthesia & Intensive Care. Sahlgrenska University Hospital.
Updated 2019-06-13


Investigation and Diagnostics of Severe Infections

SourceUnknown focusPneumoniaAbdominal infectionAcute bacterial meningitis
Cultivation of:• Peripheral blood
• CVC + arterial blood
• Urine/wound/saliva
• Peripheral blood
• CVC + arterial blood
• Tracheal mucosa/
saliva/NPH
• Peripheral blood
• CVC + arterial blood
• Peripheral blood
• CSF
Other microbiological diagnostics• Betaglucan [risk of invasive candida: prolonged ICU care (> 10 days), neutropenia, intestinal perforation, CVVHD] as needed• U-antigen pneumoc + Legionella
• Airway block (virus-PCR)
• Atypical bacterias (PCR)
• TB-diagnostics
• Pneumocystis-PCR + β-glukan as needed
• Betaglucan [risk of invasive candida: prolonged ICU care (> 10 days), neutropenia, intestinal perforation, CVVHD] as needed• CSF-PCR (bacterieas)
• HSV-1 PCR (diff - diagnosis herpes encephalitis)


Antibiotics According to Diagnosis

Initial Antibiotic Treatment in Severe Infections

SourceUnknown Foci3Pneumonia3Abdominal InfectionAcute bacterial meningitis
Community Acquired Infectiona. Pip/Taz 4g x 3-41
b. Cefotaxime 2g x 3
c. Meropenem 1g x 3-41
+/- aminoglycoside2
a. Cefotaxime 2g x 3 + Erythromycin 1g x 3
b. Phenoxymethyl-PcV 3g x 4 + Moxifloxacine 400mg x 1
a. Pip/Taz 4g x 3-41
b. Cefotaxime 2g x 3 + Metronidazol 1,5g x 1
c. Meropenem 1g x 3-41
+/- Aminoglycoside2
Meropenem 2g x 3 + Betametason 8mg x 4
Nosocomial Infection (>48 hours. after arrival to hospital)a. Pip/Taz 4g x 3-41
b. Meropenem 1g x 3-41
+/- Vancomycin3
+/- Aminoglycoside2
a. Pip/Taz 4g x 3-41
b. Meropenem 1g x 3-41 +/- Aminoglycoside2
a. Pip/Taz 4g x 3-41
b. Meropenem 1g x 3-41 +/- Aminoglycoside2
Meropenem 2g x 3 + Vancomycin 15mg/kg x 3
Neutropenia (neutrofiles ≤ 0,5)a. Meropenem 1g x 4
b. Pip/Taz 4g x 4
+/- Aminoglycoside2
a. Pip/Taz 4g x 4 + Moxifloxacine 400 mg x 1
b. Meropenem 1g x 4 + Moxifloxacine 400mg x 1
a. Meropenem 1g x 4
b. Pip/Taz 4g x 4 +/- Aminoglycoside2
Meropenem 2g x 3 + Betametason 8mg x 4
Severe allergy against beta-lactam antibiotics (anaphylactic shock, swelling/obstruction of respiratory tract)Clindamycin 600 mg x 3-4 + Ciprofloxacin 400 mg x 3 +/- Aminoglycoside2a. Clindamycin 600 mg x 3-4 + Moxifloxacine 400 mg x 1
b. Clindamycin 600 mg x 3-4 + Ciprofloxacin 400 mg x 3 (at hospitalized infection/suspicion of pseudomonas)
Clindamycin 600 mg x 3-4 + Ciprofloxacin 400 mg x 3
+/- Aminoglycoside2
a. Meropenem 2g x 3 (not in the case of shock due to beta-lactam antibiotics)
b. Moxifloxacin + Vancomycin 15mg/kg x 3 + Trim/Sulphoxazine 20 ml x 2 (in the case of shock due to beta-lactam antibiotics)
Please consider carefully• Rec. for "Unknown focus" includes urinary focus
• Necrotising soft tissue infection (Fasciitis): Meropenem 1g x 4 + Clindamycin 600 mg x 3-4 + possible. iv immunoglobuline (GAS/S. aureus)
• Endocarditis in cardiac valve disease or heart murmurs
• Malaria: Africa/Asia
• Legionella: international travel, immunosuppression, chronic lung disease
• Pneumocystis/aspergillus: immunosuppression
• Tuberculosis: origin, age, immunosuppression, addiction, long-term progression
• Influenza: Oseltamivir (Tamiflu®) 75 mg x 2 p.o. + Cefotaxime 2 g x 3
• Early "source control"
• Invasive candida: prolonged ICU care, neutropenia, intestinal perforation, CVVHD Fluconazole i.v. 800 mg x 1 day 1, then 400 mg x 1, at sepsis Micafungine 100 mg x 1
• TB meningitis: descent
• Fungal meningitis: immune suppression
• Herpes encephalitis: focal symptom Acyclovir 10 mg/kg x 3
Serious and complicated infections should be assessed by infection consultant/back-up within 24 hours or no later than next weekday.
1Betalactam antibiotics: As a result of increased volume of distribution, high and frequent doses should always be given (Pip/Taz 4g x 4, Cefotaxime 2g x 3, meropenem 1g x 4). In addition, provide an additional loading dose of selected beta-lactam antibiotic approximately 3 hours after the first dose. As the condition stabilizes, the usual dose of beta-lactam antibiotics should generally be given.
2Supplementary therapy with aminoglycoside should always be considered during sepsis and septic shock (Sepsis-3) if the infection can be caused by gram-negative bacteria (unknown focus, urosepsis, abdominal infection, VAP). Tobramycin (Nebcin©) is given at a dose of 7 mg/kg x 1. In case of obesity, the dose should be based on estimated ideal body weight. In case of increased risk of ESBL bacteria (ESBL infection, overseas care, stay in an ESBL endemic country last 6 months or treatment with cephalosporines/kinolones last 3 months) instead, amicacine is given because ESBL bacteria are often resistant to tobramycine too. Amicacin (Biklin©) is given in the dose of 25 mg/kg x 1 with dose adjustment in obese patients as above. Often enough a dose of aminoglycoside but any continued dose is controlled by conc. determination after 24 hours (lowest value).
3Supplementary treatment with Vancomycin 15 mg/kg x 3 should be considered in the known carrier of MRSA (not in urinary tract focus) and in suspected care-related KNS infection. Concentration determination before the 4th dose (lowest value). On the basis of the resistance pattern, in some cases you can choose other antibiotics.
Patient with renal failure/dialysis: The first treatment week should be done with beta-lactam antibiotics as in normal renal function. For continued dosing during dialysis, see national guidelines information at:Click here!
Antibiotic Therapy according to Diagnosis and Alternative Therapy when PcV Allergy
DiagnosisTherapyAlternative Therapy for PcV allergy
PneumoniaInj. Phenoxymethylpenicilline (Penicilline V) 1 g x 3 i.v. (also with COPD) or
T. Penicilline V 1 g x 3 or
T. Amoxicillin 500 mg x 3 (patients with COPD)
Inf. Erythromycin (Abboticin) 1 g x 3 i.v. or
T. Eryhtromycin 500 mg x 2 or.
T. Doxycycline 100 mg x 1 (at COPD; double dose the first day)
Pyelonephritis/Febrile Urinary Tract InfectionInj. Tobramycin (Nebcin*) 4,5 mg/kg x 1 i.v.
alt. Inj. Cefotaxime 1 g x 3 i.v. alt.
T. Ciprofloxacin 500 mg x 2
Inj. Tobramycin (Nebcin*) 4,5 mg/kg x 1 i.v.
Acute Cystitis T. Nitrofurantoin (Macrobid) 50 mg x 3 alt.
T. Pivmecillinam 200 mg x 3
 
Erysipelas (Streptococcus)Inj. Phenoxymethylpenicilline (Penicilline V) 1-3 g x 3 i.v. alt. T. Penicilline V 1 g x 3Inf. Clindamycin 300 mg x 3 i.v. alt. C. Clindamycin 300 mg x 2-3
Skin and soft tissue infection (S. aureus)Inf. Cloxacillin 2 g x 3 i.v. alt. T. Flucloxacillin 1 g x 3Inf. Clindamycin 300 mg x 3 i.v. alt. C. Clindamycin 300 mg x 2-3
Abdominal infectionInj. Piperacillin/Tazobactam 4 g x 3 i.v. alt. Inj. Cefotaxime 1 g x 3 i.v. + Inf. Metronidazole 1 g x 1 i.v. alt.
Inj. Meropenem (Merrem) 0,5 g x 3 i.v. (in case of severe, complicated infection)
Inf. Ciprofloxacin 400 mg x 2 i.v. + Inf. Clindamycin 600 mg x 3 i.v.
Severe bacterial infection of unknown origenInj. Phenoxymethylpenicilline (Penicilline V) 1 g x 3 i.v. + Inj. Tobramycin (Nebcin*) 4,5 mg/kg x 1 i.v. alt.
Inj. Cefotaxime 1 g x 3 i.v.
Inj. Tobramycin (Nebcin*) 4,5 mg/kg x 1 i.v. + Inf. Clindamycin 600 mg x 3 i.v.

Dose of tobramycin (Nebcin®) in patients with renal failure

Creatinine Clearance> 80 80-4140-20
Dose:5-7 mg/kg × 14.5-2.2 mg/kg × 12.2-1 mg/kg × 1
Dose is determined after weight at lean body mass.
Determination of S-conc. of tobramycin 8 hours after given dose and should then amount to 1.5-4.0 mg/L

Choice of Antibiotics in Intensive Care

Community Acquired Infection. Severe Sepsis/Septic Shock

Sepsis of unknown origenA) Piperacilline/Tazobactam 4 g x 4 + Tobramycin (Nebcin®) 5-7 mg/kg x 1
B) Meropenem 1 g x 4 + Tobramycin (Nebcin®) 5-7 mg/kg x 1
PneumoniaA) Cephotaxime 1 g x 3 + Erythromycin (Abboticin®) 1 g x 3 + Tobramycin (Nebcin®) 5-7 mg/kg x 1
B) Phenoxymethylpenicilline 3 g x 4 + Moxifloxacin (Avelox®) 400 mg x 1 + Tobramycin (Nebcin®) 5-7 mg/kg x 1
Abdominal infectionA) Piperacillin/Tazobactam 4 g x 3 + Tobramycin (Nebcin®) 5-7 mg/kg x 1
B) Meropenem 1 g x 4 + Tobramycin (Nebcin®) 5-7 mg/kg x 1
Fasciitis/myositisA) Meropenem 1 g x 4 (alt. Phenoxymethylpenicilline 3 g x 4 with verified grp A strpc) + Clindamycin 600 mg x 3 + Tobramycin 5-7 mg/kg x 1 (not with Strpc A)
MeningitisMeropenem 2 g x 3

Community Acquired Infection without Severe Sepsis/Septic Shock

Sepsis of unknown origenPiperacillin/Tazobactam 4 g x 3-4
PneumoniaA) Cephotaxime 1 g x 3 + Erythromycin (Abboticin®) 1 g x 3
B) Phenoxymethylpenicilline 3 g x 4 + Moxifloxacin (Avelox®) 400 mg x 1 +
Abdominal infectionA) Piperacillin/Tazobactam 4 g x 3
B) Cephotaxime 1 g x 3 + Metronidazol 1.5 g x 1
C) Meropenem 0.5 g x 3
Fasciitis/myositisMeropenem 1 g x 4 (alt. Phenoxymethylpenicilline 3 g x 4 at verif group A strpcocc) + Clindamycin 600 mg x 3
MeningitisMeropenem 2 g x 3

Nosocomial Infection (Hospital Acquired) (>48 hours in hospital)

Sepsis of unknown origenA) Meropenem 0,5-1 g x 3-4 + ev. Tobramycin (Nebcin®) 5-7 mg/kg x 1
B) Piperacillin/Tazobactam 4 g x 3 + ev. Tobramycin (Nebcin®) 5-7 mg/kg x 1
PneumoniaA) Piperacillin/Tazobactam 4 g x 3-4 + ev. Tobramycin (Nebcin®) 5-7 mg/kg x 1
B) Meropenem 0,5-1 g x 3-4 + ev. Tobramycin (Nebcin®) 5-7 mg/kg x 1
Abdominal infectionA) Piperacillin/Tazobactam 4 g x 3-4 + ev. Tobramycin (Nebcin®) 5-7 mg/kg x 1
B) Meropenem 0,5-1 g x 3-4 + ev. Tobramycin (Nebcin®) 5-7 mg/kg
Fasciitis/myositisMeropenem 1 g x 3-4 + ev. Tobramycin (Nebcin®) 5-7 mg/kg
MeningitisMeropenem 2 g x 3 + Vancomycin 1 g x 3 (after Neurosurgery)

Immune Deficiency Patients with Neutropenia (Neutrofiles < 0.5)

Sepsis of unknown origenA) Meropenem 0,5-1 g x 4 + ev. Tobramycin (Nebcin®) 5-7 mg/kg
B) Piperacillin/Tazobactam 4 g x 4 + ev. Tobramycin (Nebcin®) 5-7 mg/kg
PneumoniaA) Meropenem 0,5-1 g x 4 + Erythromycin (Abboticin®) 1 g x 3 + ev. Tobramycin (Nebcin®) 5-7 mg/kg
B) Piperacillin/Tazobactam 4 g x 4 + Erythromycin (Abboticin®) 1 g x 3 + ev. Tobramycin (Nebcin®) 5-7 mg/kg
Abdominal infectionA) Piperacillin/Tazobactam 4 g x 4 + ev. Tobramycin (Nebcin®) 5-7 mg/kg
B) Meropenem 0,5-1 g x 4 + ev. Tobramycin (Nebcin®) 5-7 mg/kg
Fasciitis/myositisMeropenem 1 g x 4 (alt. Phenoxymethylpenicilline 3 g x 4 at verif group A strpk) + Clindamycin 600 mg x 3
MeningitisMeropenem 2 g x 3

Serious Penicillin/Cefalosporin Allergy

Sepsis of unknown origenClindamycin 600 mg x 3 + Ciprofloxacin 400 mg x 3 + Tobramycin (Nebcin®) 5-7 mg/kg
PneumoniaClindamycin 600 mg x 3 + Moxifloxacin (Avelox®) 400 mg x 1 (vid VAP Ciprofloxacin 400 mg x 3) + ev. Tobramycin (Nebcin®) 5-7 mg/kg
Abdominal infectionClindamycin 600 mg x 3 + Ciprofloxacin 400 mg x 3 + ev. Tobramycin (Nebcin®) 5-7 mg/kg
Fasciitis/myositisClindamycin 600 mg x 3 + Ciprofloxacin 400 mg x 3 + ev. Tobramycin (Nebcin®) 5-7 mg/kg
MeningitisA) Meropenem 2 g x 3 (not at anaphylactic shock of PcV) + Vancomycin 1 g x 3
B) Moxifloxacin (Avelox®) 400 mg x 1 + Vancomycin 1 g x 3 + Trimetoprim Sulfametoxazol 20 ml x 2

NOTE! Always take culture samples from relevant locations before starting treatment with antibiotics, such as blood, sputum, wounds and urine.

In severe sepsis, the addition of tobramycin (Nebcin®) during the first day at the dose of 5-7 mg/kg × 1 on creatinine clearance > 80; 4.5-2.2 mg/kg × 1 on creatinine clearance 80-41; 2.2-1 mg/kg × 1 of creatinine clearance 40-20; Weight – lean body mass. Determination of S-conc. of tobramycin 8 hours after given dose and should then amount to 1.5-4.0 mg/L.

Dose of tobramycin (Nebcin®) in patients with renal failure

Creatinine Clearance> 80 80-4140-20
Dose:5-7 mg/kg × 14.5-2.2 mg/kg × 12.2-1 mg/kg × 1
Dose is determined after weight at lean body mass.
Determination of S-conc. of tobramycin 8 hours after given dose and should then amount to 1.5-4.0 mg/L

The dosing instructions require an adult patient with normal renal function.

Creatinine clearance (ml/min) = F x (140-age) x weight/S-creatinine (F ≈ 1,2 for men; F ≈ 1.0 for women).

At increased risk of ESBL-forming intestinal bacteria (international travels, international care, known support): Meropenem 1g x 4 + Amicacin (Biklin®) 20-25 mg/kg x 1. In case of fasciitis/myositis contact an infection physician for positioning in case of i.v. immunoglobulin. In meningitis, supplementation with betamethasone (Betapred®) 8 mg x 4 is recommended.

Higher doses and denser dosage in severe sepsis/septic shock due to increased volume of distribution and reduced microcirculation. Usually lower/sparse dosage later in the process. Addition of Nebcin® 1 dose/day in severe sepsis/septic shock. Normal dose 7 mg/kg. Lower dose (5 mg/kg) at high age or chronic renal failure. Refrain from Nebcin® at GFR < 20 ml/min. During treatment with Biklin®, control of S-concentration, i.e. immediately before the next dose.


Antibiotics in Patients with Renal Impairment

Antibiotics in Case of Impaired Renal Function
Creatinine Clearance (ml/min)> 80 ml/min80-41 ml/min40-20 ml/min< 20 ml/min
Ampicillin2 g x 32 g x 32 g x 21 g x 2
Phenoxymethylpenicilline 1 g x 31 g x 31 g x 21 g x 2
Cloxacillin2 g x 32 g x 31 g x 31 g x 3
Piperacillin + tazobactam4 g x 34 g x 34 g x 34 g x 2
Cefotaxime1 g x 31 g x 31 g x 21 g x 2
Ceftazidime at neutropenia1 g x 3

1 g x 4
1 g x 2

1 g x 3
0,5 g x 2

0,5 g x 3
0,5 g x 1

0,5 g x 2
Meropenem at neutropenia0,5 g x 3

0,5 g x 4
0,5 g x 3

0,5 g x 4
0,5 g x 2

0,5 g x 3
0,25 g x 2

0,5 g x 2
Ciprofloxacin400 mg x 2400 mg x 2400 mg x 1400 mg x 1
Tobramycin*6-4,5 mg/kg x 14,5-2,2 mg/kg x 12,2-1 mg/kg x1 

Antibiotics Independent of Renal Function
Generic SubstanceDifferent label names:
DoxycyclineDoxyfermDoryxDoxyhexalDoxylin
ErytromycinEry-MaxErycErythrocin
FucidinFucidinFucithalmicStafine
ClindamycinClindamycinCleocinDalacinClinacin
MetronidazoleFlagylMetro
RifampicinRimactanRifadin
High Bioavailability after Oral Administration (> 90%)
Generic SubstanceDifferent label names:
DoxycyclineDoxyfermDoryxDoxyhexalDoxylin
Fluconazol Fluconazol
Clindamycin Clindamycin
MetronidazolFlagylMetro
Trimetoprim Sulfametoxazol EusaprimBactrim


Common Antibiotics to Children

Recommended Doses of Parenteral Antibiotics to Children

MedicationConcentrationDoseNote
Erythromycin (Abboticin®)10-15 mg/kg x 3Caution in liver failure and in heart disease (arrhythmias). Dose reduction in renal impairment.
Phenoxymethylpenicilline (Bensyl PCV)100 mg/ml25-50 mg/kg x 3 (3g x 3) alt. 50-100 mg/kg x 4 (3 g x 4)
Cefotaxime (Cefotaxim®)100 mg/ml30 mg/kg x 3. (1g x 3) alt. 75-100 mg/kg x 3 (3 g x 3)
Ceftazidime (Ceftazidim®)100 mg/ml25 mg/kg x 3 (1 g x 3) alt. 50 mg/kg x 3 (2 g x 3) alt. 35 mg/kg x 3 (2 g x 3) Children< 2 months: 25 mg/kg x 2 Diluted with sterile water. Given for 3-5 min.
Cefuroxime (Cefuroxime®)100 mg/ml20-30 mg/kg x 3 (0,75-1,5 g x 3)Diluted with sterile water. Given for 3-5 min.
Clindamycin (Dalacin®)10 mg / kg x 3 (600 mg x 3)
No child <4 weeks age
Cloxacillin (Cloxacillin®)50 mg/mlDiluted with sterile water. Given in CVC 3-5 min. All infusion in pvc: Then dilute once more with NaCl 9mg/ml to 20 mg/ml. 20-30 min.
Meropenem (Meronem®)50 mg/ml40 mg/kg x 3 (2 g x 3) alt. 20 mg/kg x 3-4 (2 g x 3-4) alt. 10-20 mg/kg x 3 (0,5-1 g x 3)Diluted with sterile water. Given for 3-5 min.
Tobramycin (Nebcin®)10 mg/ml7.5 mg/kg x 1. Higher dose 8-10-(12) mg/kg x1
can be used in CF and neutropenic fever.
Nebcina 40 mg/ml is diluted with NaCl 9 mg/ml alt. Glucose 50 mg/ml. Infusion for 20-60 min.
Vancomycin (Vancocin®)5 mg/ml20 mg/kg x 2 (-3) (1 g x 2) ev x 3Diluted in two steps. First stock solution with sterile water to 50 mg/ml. Then dilute with sodium chloride 9 mg/ml or glucose 50 mg/ml to 5 mg/ml. Infusion for at least 60 minutes.
Piperacillin/Tazobactam80 mg/kg x 3-4 alt. 100 mg/kg x 3-4 (4 g x 3-4)
Ceftriaxone (Rocephalin®)100 mg/kg x 1. (2 g x 1)
Linezolid (Zyvoxid®)10 mg/kg x 2 (600 mg x 2)(max 28 days)

Bacterial Sensitivity to Various Antibiotics

The above tables show the susceptibility of bacteria to different antibiotics. Published with permission from UAS. The images are clickable to be viewed in more detail in higher resolution. Different colors indicate classes of antibiotics.