Chemoprophylaxis Flashcards
Define chemoprophylaxis
Use of antimicrobial drug to prevent an infection
Not yet established infection
Not immunisation
E.g. anti-malarial drugs to prevent malaria in travellers
Chemoprophylaxis should only be considered when some or all of what factors are present?
Significant and predictable risk of infection
Consequences of infection may be serious
Period of highest risk can be ascertained
Microbial causes of infection are predictable
Antimicrobial sensitivities are predictable
Cheap and safe ones available
Disadvantages to chemoprophylaxis
Cost Adverse effects Disturbance of flora Colonisation with more antibiotic-resistant bacteria Selection of antibiotic resistance
Risk of inappropriate chemoprophylaxis e.g. preventing UTI in patients with urinary catheters- can’t predict what bacteria will infect
There are different regimes in different areas for malaria. List some regimens available
Chloroquine (and of proguanil)
Mefloquine
Doxycycline, malarone (proguanil and ataovaquone)
They are continued for 4 weeks after leaving malarious area
Examples of chemoprophylaxis
Invasive group A strep infections - penicillin
Group B strep infections - penicillin or clindamycin
Rheumatic fever
Bacterial meningitis and meningococcal disease- rifampicin, ciprofloxacin or cetriaxone
Bacterial meningitis - Hib - rifampicin
Recurrent UTIs -trimethoprim, nitrofurantion, cephalexin
Procedure of chemoprophylaxis in splenectomised patients
Penicillin to prevent pneumococcal infections
Also used on children with sickle cell disease Compliance issue
Highest risk in the first 2 years following splenectomy
Immunosuppressive patients, examples of prophylaxis
HIV - co-trimoxazole, when CD4 count <200 or to prevent PCP following 1st infection
Neutropenia - ciprofloxacin to prevent gram-negative bacterial infections
BOne marrow transplant - ciprofloxacin and aciclovir to prevent herpes simplex virus and fluonazole to prevent candida infections
Producer of prophylaxis after trauma/bites
Co-amoxiclav and metronidazole, doxycycline if pet allergic
Tetanus booster
Endocarditis and prophylaxis?
No longer recommended
Was given to prevent bacteria seeding heart valves and causing endocarditis
What’s a clean surgical operations and is prophylaxis provided
No where near mucosa surface where bacteria may be
Hernia repair, mastectomy
NO
What is clean with implant operation and is prophylaxis provided?
Implant procedure but not near a mucosal surface.
Mastectomy with great implant, hip replacement, heart valve replacement
YES, prevention of infection with skin organisms of low pathogenicity
What is a contaminated surgical operation, is prophylaxis provided?
Operation involving a mucosal surface
Elective colorectal surgeries
Yes! Predictable risk of bacterial contamination of surgical field
What is a dirty surgical operation, is prophylaxis provided?
Operation where infection is already present
Emergency colorectal surgery with peritonitis
No! Requires full course of antibiotics
Name the common faults with surgical antibiotic prophylaxis
Used for clean operations
Used for too long (max 24 hours)
Often given without regard to previous microbiology reports or recent antibiotic treatment. The first prophylaxis will alter flora so second time will be different.
List the prophylaxis regimen for influenza A
When circulating in the community. Antiviral prophylaxis is offered to in-immunised at risk contacts of cases Ideally within 48 hours of exposure .age >65 .chronic resp, cardiac, renal etc .pregnancy
Given oseltamivir or zanamivir
