Category Microbiology

The old antibiotics are still useful – Fosfomycin

The Special Access Scheme (SAS) allows practitioners to import/gain access to therapeutic goods currently not registered on the Australian Register of Therapeutic Goods (ARTG) for a single patient on a case by case basis. Fosfomycin (one such SAS drug) is a broad spectrum antibiotic belonging to the phosphonic acid derivative drug class (other examples in this drug class include foscarnet and adefovir).

Pathology stewardship – an essential element of AMS

Poor antimicrobial prescribing decisions often are triggered by laboratory results that create red herrings or worse.  Inappropriate/ poor specimen collection and/or a request form that provides no context to the investigation often sets the ball rolling.  Inappropriate workup and reporting of contaminant or colonising isolates may then follow (it may be impossible for the lab […]

Micro lab comments: candidaemia and candiduria

Candidal bloodstream infection represents a high risk infection, even for immunocompetent patients. Mortality is significant even for IV line-associated candidaemia.  Blood cultures are seldom contaminated by fungi and any patient with an isolate must be subjected to careful clinical assessment. Our comment serves to give a few reminders that follow on from the liaison between the […]

Micro comments: Clostridium difficile testing

Here are our local Pathology North (NSW) comments together with their rationale: Positive CDI test result comment (no test of clearance required!): The duration of contact precautions following recovery are controversial. Patients will continue to excrete C. difficile for weeks following recovery and can represent a cross infection risk. However continent patients with formed stool who […]

Microlab comment: beta-haemolytic streptococci isolated from blood

Here is another one used for uncomplicated bloodstream infection events: Infections due to these species of streptococci are usually rapidly responsive to appropriate antibiotic therapy which can be of short duration with no minimum IV requirement as endocarditis is not a usual consideration.  Penicillin resistance has not been documented and flucloxacillin is just as active (see […]

Micro comments unpacked: Gram negative bacteraemia

Here is an example comment from Pathology North which is added to positive blood culture reports when a Gram negative coliform species ( Enterobacteriacae eg. E. coli) has been isolated: The comment’s rationale is to promote short course treatment and also to prompt oral antibiotic switching in a timely manner.  It also prompts consideration of source […]

Essential clinical care of Staphylococcus aureus bloodstream infection (SAB)

201 cases of SAB were managed across Hunter New England Health last year. The overall 30 day all-cause mortality was 22% (30% in those patients 60 years or above).  Relapse of infection occurs in 2-10% of adult patients and may occur up to 3 months after the original bacteraemia. Relapse rates are reduced but not eliminated […]

Why do Gram positive and Gram negative bacteria show different antibiotic susceptibility patterns?

The terms Gram positive and Gram negative are commonly used to describe bacteria. The main difference between the two is the structure of their cell wall which changes their susceptibility to different antibiotics.  The separation also loosely fits the location of these organisms in the body – Gram negative organisms predominate in the bowel (eg. […]

Testing urine from a patient with a urinary catheter – CEC protocol under piloting in NSW

Urines are frequently collected from minimally symptomatic patients.  Detection of bacteriuria and reporting of antibiotic susceptibility is a  frequent prompt for unnecessary antibiotic treatment, especially in residential aged care settings. This new protocol codifies best practice recommendations for collection of urine cultures. It is being trialed at Belmont Hospital in Hunter New England. Clinical Excellence […]