Gastro-Intestinal System

Microbiological Specimens:

  • Acute diarrhoea: single stool sample (plus blood culture if pyrexial / immunocompromised or enteric fever) If the patient has travelled overseas please provide details of countries of travel as the laboratory testing protocol requires this information.
  • Amoebiasis: fresh sample transported to laboratory ASAP
  • Chronic diarrhoea / Giardia / helminth infections: 3 or more stool samples maybe required
  • Stool sample (which takes the shape of the container) for all suspected cases of Clostridium difficile infection ASAP
  • The choice of agent should take into account the patient’s risk for C. difficile infection.
  • PLEASE note faecal samples or Blood culture are appropriate tests for enteric fever, serology is no longer used.

C. difficile infection: Discuss all cases (primary or recurrent) with Microbiologist during working hours; Where possible – stop antibiotics and PPIs; maintain daily bowel chart; fluid and electrolyte monitoring; and emphasize on nutrients intake.

Common Pathogen(s)
Toxigenic E. coli;
Rotavirus;
Norovirus;
Enteric adenovirus;
Astrovirus.

Antibiotic – 1st line
No antibiotics indicated

Comment
Notify Infection Control immediately Ext. 53784.
Mainstay of treatment is fluid replacement.

C difficile infection CDT toxin positive and all GDH positive cases MUST be discussed with Microbiology/ID physician during working hours and assessed for trial eligibility. Regimes below are for dosing details as directed by the above team. See CDI policy

  • IV vancomycin is not indicated for the treatment of C. difficile infection.
  • Oral vancomycin is reserved for severe / recurrent infections.
  • Vancomycin capsules are available for oral use for C diffcile infections but after risk assessment – ward 8 (isolation ward) can use the vancomycin injections orally which is more cost effective – see protocol on ward 8 for full details.

Vancomycin 500mg vial can be reconstituted with 10mls of water for injection to give a concentration of 125mg in 2.5ml. This may be further diluted with water to approximately 30ml before administrating. Squash may be added at the time of administration to improve taste if taken orally. Reconstituted solution should be stored in the fridge and used within 96hours.

i.e. ≤ 5 stools in 24 hours, WCC ≤15 x 109 cells/L; and no features of severe disease* (see below).
Review signs and symptoms and follow SEVERE Clostridium difficile protocol if patient has severe disease

Immunocompromised patients should be discussed with microbiologist during working hours

Pathogen(s): Clostridium difficile.

Antibiotic – 1st line
Metronidazole 400mg PO q8h for 14 days.

If no improvement in stool frequency/ consistency at 6 days, discuss with microbiologist during working hours

 

2nd line
Vancomycin should only be used in the following circumstances:

Severe disease; failure to respond to > 6 days Metronidazole, critically ill patients, intolerance/ allergy to Metronidazole, pregnant, severe pseudomembranous colitis.

Vancomycin 125mg PO/NG q6h for 14 days

Comment
Commence bowel chart.
Daily review of nutrition, fluid and electrolyte balance.
Use Metronidazole 500mg q8h IV if Nil-By-Mouth, no NG or PEG-tube access, or if patient has ileus. (IV metronidazole is not as effective as oral for treating CDI)

*Severe disease (if any of the following below):
Critically ill;
WBC > 15 x 109 cells/L;
Acute rise serum creatinine >50% above baseline;
Temperature > 38.5ºC;
Albumin < 25g/L;
Impending ileus;
Colonic dilatation;
Abdominal pain / distension;
Pseudomembranous colitis;
Radiology: Caecal dilatation >10cm.

Number of stools maybe a less reliable indicator of severity.

Immunocompromised patients should be discussed with microbiologist during working hours

Pathogen(s): Clostridium difficile.

Antibiotic – 1st line
All cases of severe disease MUST be discussed with microbiologist at the 1st opportunity during working hours..Vancomycin 125mg PO/NG q6h 14 days.

 

2nd line
Life threatening CDI must be discussed with Microbiologists at 1st opportunity during working hoursVancomycin 125-500mg NG/PO q6h +/- metronidazole IV 500mg q8h for 14days*

Comment
Commence bowel chart.

Daily review of nutrition, fluid and electrolyte balance.

  • Duration outside PHE guidelines on C difficile management due to local epidemiology

Severe cases require MDT input from Microbiologist, Gastroenterologist and General surgeon as definitive management beyond caecal dilatation >10cm is surgical.

Antibiotic – 1st line
Discuss all recurrent episodes with Microbiologist during working hours before commencing treatment so that trial eligibility can be assessed. If not on trial

Mild/ Moderate:  Vancomycin 125mg PO/NG q6h for 14 days

Severe infection:  Vancomycin 125mg PO/NG q6h plus Metronidazole 500mg q8h IV for 14 days
Discuss all primary and recurrent episodes with Microbiologist at 1st opportunity during working hours.

Discuss with Consultant Microbiologist during working hours. Review regularly. If failure to respond to treatment, urgent Microbiology / Gastroenterology review required.

Indiscriminate vancomycin can result in selection of Vancomycin Resistant strains. Vancomycin Tapering Course should be used only after discussion with microbiologist during working hours

Further recurrences  should be treated individually.

Further recurrences must be discussed with Microbiology/ Gastroenterology at 1st opportunity during working hours

Duration 7 days

MOSTLY self-limiting AND DOES NOT REQUIRE ANTIBIOTIC TREATMENT; treat if immunocompromised or if severe infection.

1st line 
Clarithromycin 500mg PO q12h

 

2nd line 
Ciprofloxacin 500mg PO q12h

Pathogen(s): Helicobacter pylori.

Antibiotic – 1st line
Omeprazole 20mg q12h PO plus Amoxicillin 1g q12h PO plus Clarithromycin 500mg q12h PO for 7 days

 

Antibiotic – 2nd line
Discuss with gastroenterologists for other choices
Or
Omeprazole 20mg q12h PO plus Clarithromycin 500mg q12h PO plus Metronidazole 400mg q12h PO for 7 days

Comment
Urea breath test for diagnosis.

If eradication therapy fails, discuss with Consultant Gastroenterologist.

Maintenance PPI regimes MAY be required as indicated by Gastroenterologist.

Pathogen(s): Giardia lamblia.

Antibiotic – 1st line
Metronidazole 400mg PO q8h for 5 days
or
Metronidazole 2g PO q24h for 3 days.

 

2nd line
Discuss with Consultant Microbiologist during working hours.

Pathogen(s): Entamoeba histolytica.

Antibiotic – 1st line
Metronidazole 400mg PO q8h for 5 days
plus
Diloxanide Furoate500mg PO q8h for 10 days.

 

2nd line
Discuss with Consultant Microbiologist during working hours.

Comment
Discuss with Consultant Microbiologist during working hours if Amoebiasis suspected.

Common Pathogen(s)
Non-typhoidal Salmonella (food poisoning);
Shigella spp.

Antibiotic – 1st line
Antibiotics only recommended in immunocompromised patients, febrile neutropenia, asplenia, sickle cell disease febrile elderly patients, immunocompetent with invasive disease or typhoid/paratyphoid .

Discuss with Consultant Microbiologist.

Duration of therapy 7 days

Common Pathogen(s)
Polymicrobial gastrointestinal flora Gram-negative bacilli, including Enterobacteriaceae Anaerobes, including bacteroides

Antibiotic – 1st line
Amoxicillin 1g IV q8h
plus 
Metronidazole 500mg IV q8h.
plus 
Gentamicin (click here for full gentamicin policy)
Note: If serum creatinine is not yet known then 5mg/kg may still be initiated unless 70years or above or there is evidence of existing severe renal impairment. CrCl must still be calculated once U+Es are available. ALL SUBSEQUENT DOSES MUST BE ADJUSTED AS PER CrCl once known. Must check pre-dose level as per policy.5mg/kg IV q24h (max 500mg): if <70 years and CrCl≥30mL/min  or
3mg/Kg IV q24h (max 300mg): If ≥70 years or CrCl 10-29.9ml/min, known renal impairment, or clinician has concerns about higher dose (e.g. clinical signs of renal impairment)
Round to nearest 20mg for ease of administration
CrCl known to be under <10ml/min discuss with microbiology during working hours for gentamicin dosing/or alternative antibiotic recommendation.
If patient is obese ie. 20% over ideal body weight – use adjusted body weightOral step down on ward: amoxicillin 500mg-1g PO q8h plus metronidazole 400mg PO q8h and review and discuss with microbiologist during working hours.
For discharge – co-amoxiclav (consider C difficile risk factor) 625mg PO q8h to complete 7 days duration

 

2nd line
Metronidazole 500mg IV q8h
plus 
Gentamicin (click here for full gentamicin policy) 
Note: If serum creatinine is not yet known then 5mg/kg may still be initiated unless 70years or above or there is evidence of existing severe renal impairment. CrCl must still be calculated once U+Es are available. ALL SUBSEQUENT DOSES MUST BE ADJUSTED AS PER CrCl once known. Must check pre-dose level as per policy.5mg/kg IV q24h (max 500mg): if <70 years and CrCl≥30mL/min  or
3mg/Kg IV q24h (max 300mg): If ≥70 years or CrCl 10-29.9ml/min, known renal impairment, or clinician has concerns about higher dose (e.g. clinical signs of renal impairment)
Round to nearest 20mg for ease of administration
CrCl known to be under <10ml/min discuss with microbiology during working hours for gentamicin dosing/or alternative antibiotic recommendation.
If patient is obese ie. 20% over ideal body weight – use adjusted body weight

Or if gentamicin contraindicated – cefuroxime 1.5g IV q8h plus metronidazole 500mg IV q8h