This document provides an overview of common bacterial infections and appropriate antibiotic treatment. It lists different types of antibiotics that are bacteriocidal or bacteriostatic. It also describes different types of bacteria including their Gram staining characteristics and whether they have cell walls. Common bacterial infections like pneumonia, urinary tract infections, cellulitis, and diarrhea are discussed along with typical causative organisms and recommended antibiotics. The document stresses the importance of confirming the diagnosis, using the right antibiotic at the correct dose and duration, and de-escalating once sensitivities are known.

1. The basics
Brooke Sachs 2017

2. http://tmedweb.tulane.edu/pharmwiki/doku.php/antibiotic_targets

3.  Bacteriocidal antibiotics
 Beta lactams
 Vancomycin
 Daptomycin
 Fluoroquinolones (ciprofloxacin)
 Metronidazole
 Nitrofurantoin
 co-trimoxazole
 Aminoglycosides (gentamycin)
 Bacteriostatic antibiotics
 Chloramphenicol
 Lincosamides (Clindamycin)
 Ethambutol
 Macrolides (azithromycin etc)
 Sulfonamides (sulfamethoxazole)
 Tetracyclines (doxycycline)

4. http://alkam.tripod.com/GRAM.HTM

5. https://en.wikipedia.org/wiki/Gram-positive_bacteria

6.  Obligate intracellular bacteria
 Rickettsia
 Chlamydia
 No cell wall
 Mycoplasma
 Spirochetes
 Treponema pallidum (syphillis) – gram negative, thin, spiral shape
 Borrelia
 Leptospira
 Mycobacterium
 Thick mycolic acid cell wall means neither gram negative nor gram positive
 Aerobic, acid fast (Ziehl-Neelson stain)

7. https://commons.wikimedia.org/wiki/File:Bacterial_infections_and_involved_species.png

8.  The right DRUG
 The right DOSE
 DE-ESCALATION to pathogen-directed therapy
 The right DURATION

9.  Things that cause fevers that aren’t
bacteria:
 Viral infections
 Pancreatitits
 Operations and post-operative atelectasis
 PE/DVT/fat embolus
 Subarachnoid haemorrhage
 Myocardial infarct, stroke, ischaemic
bowel
 Cancer, tumour lysis syndrome
 Drugs
 Alcohol/drug withdrawal
 Gout/rheumatic processes
 ARDS, aspiration pneumonitis
 Transfusion
 Transplant reaction
 Adrenal insufficiency
 Thyrotoxicosis, thyroiditis
 Phelbitis/thrombophlebitis
 Infections that don’t need antibiotics:
 Small skin abscesses that will self-resolve
 Asymptomatic bacturia (except in specific
cases)
 Bacterial colonisation (e.g. coag-negative
staph from a skin swab)
http://www.derangedphysiology.com/main/required-reading/infectious-diseases-antibiotics-and-sepsis/Chapter%203.7.0/infectious-and-non-infectious-causes-fever

11.  Most commonly affected by aerobic bacteria, due to the available oxygen
 Can be gram positive or gram negative, mycoplasma, tuberculosis
 CURB-65, SMART-COP for assessing severity
 Stratification will help decide in/outpatient treatment and strength of antibiotics
if required
 Make sure to do appropriate tests – CXR, respiratory viral swab, sputum culture,
2x blood culture, routine chemistry, urine legionella/pneumococcal antigens
 Treated empirically based on the most common causes
 B-lactams for the gram-positive bacteria
 Tetracyclines/macrolides for atypicals
https://www.safetyandquality.gov.au/wp-content/uploads/2012/02/3.3-Adult-Pneumonia-CPG-CAP-HAP-combined-post-AQUM-HNE-Health.pdf

12.  Diagnosis based on clinical symptoms, UA and urine culture
 Most common cause is E. coli
 Treatment depends on how high up the tract the infection goes (cystitis mostly
outpatient, pyelonephritis inpatient)
 Often treated with agents that act on protein synthesis, but also use ampicillin
www.nps.org.au/medical-info/consumer-info/urinary-tract-infections-utis

13.  Often aerobic
 Staph, strep, pseudomonas are the most common bacteria
 Cellulitis often requires treatment, though small areas can be monitored
 Often treat with cephalosporins, tetracyclines (doxy), erythromycin
 Beware of MRSA
http://www.medscape.org/viewarticle/529347

14.  Most diarrhoea, even if from a bacterial cause, will be self-resolving
 Beware C.diff (treat with metronidazole or vancomycin PO)
 H. pylori requires multi-modal therapy
 Ascending cholangitis is life-threatening (and often the infection is secondary to
another cause that must be treated)

15.  Sore throats can spell strep throat, and the association with rheumatic fever
means antibiotics are required in those scoring highly on the Centor Criteria
 New murmurs require investigation – and empiric treatment is often warranted
 The new severe headache or neurological syndrome may be a CNS infection –
consider LP BEFORE antibiotic administration where possible and remember
many antibiotics do not penetrate the BBB easily