Emergence of antibiotic resistance in pathogens is a global
threat to human health and a matter of grave public health concern. Resistance of
micro-organisms towards an antibiotic renders it ineffective in curing any disease
caused by those organisms. Some micro-organisms develops resistance to a wide
range of antibiotics including even to newer and more potent antibiotics such
as Carbapenems, making treatment of patient difficult, costly and sometimes
impossible. Due to this antibiotic
resistant micro-organisms leads to increased mortality, morbidity and
healthcare costs.
A major reason of emergence of antibiotic resistant strains
of micro-organism is indiscriminate and irrational use of antibiotics. It is
estimated 50% of antibiotic usage in Indian hospitals are inappropriate and
irrational. Hence, there is an urgent need that hospitals formulate and
implement appropriate Antibiotic Policy that ensures rational use of
antibiotics and prevent any indiscriminate use. This post describes how should be
a hospital’s Antibiotic Policy and what should it contain.
Antibiotic Policy serves as a guideline for doctors to
decide which antibiotic shall be used for treating a specific infectious condition. It also states
practices that must be followed while using Antibiotics on patients. The antibiotic policy must ideally be developed collaboratively. Pharmacotherapeutic committee or the Infection control committee can take a lead role in formulation of this policy, with inputs from all clinical departments.
An antibiotic policy must include following sections
POLICY FOR PRESUMPTIVE VS. DEFINITIVE APPROACH IN ANTIBIOTIC THERAPY
When an antibiotic therapy is used based on clinical
diagnosis of an infection and on educated experience of probable pathogen that
might be causing the infection, it is called as presumptive antibiotic therapy. Against this, using antibiotic
therapy when infection is confirmed by micro-biological test and identifying
the micro-organism causing the infection either by isolating it in the lab or
by other direct evidence, is called as definitive
antibiotic therapy.
The antibiotic policy must state definitive antibiotic
therapy as a preferred approach for treating infections. The presumptive
therapy can be started based on patient’s condition and urgency of the
situation and should be replaced by appropriate antibiotic as soon as
definitive results are available. For example, patients in septic shock or
bacterial meningitis, presumptive therapy can be initiated immediately after or
concurrently with collection of diagnosis specimen. In conditions where patient
is stable, presumptive therapy should be deliberately delayed till the time
appropriate sample has been collected and sent to microbiology.
Before starting of presumptive therapy, following things
must be ensured
·
Standard investigations for all suspected
infections have been sent for
·
Antibiotic shall be started only after
appropriate samples has been sent for culture
·
Antibiotic Sensitivity profile of the organism
isolated must be taken into consideration for continuation or change of
antibiotic being used for therapy
·
Antibiotic therapy must be reviewed daily and
adjustments shall be made accordingly, especially after culture reports are
available.
RECOMMENDED ANTIBIOTICS FOR PRESUMPTIVE THERAPY
A
large and important section of the Antibiotic Policy constitutes of a table
that recommends first line and second line antibiotics to be used for specific
conditions on a presumptive basis. The table must have following columns. Few
examples (Referred from ‘National Treatment Guidelines for Antimicrobial use’,
Version 1, 2016), is stated for a better understanding. Hospitals should make
their own policy based on specialities they offer and type of microbes in their
local area.
Condition
|
Likely Causative Organism
|
Presumptive antibiotic –
First line
|
Presumptive antibiotic – second
line
|
Comments
|
Central Nervous System Infections
|
||||
Acute bacterial meningitis
|
S. pneumoniae, H.influenzae, Neisseria meningititidis
|
Ceftriaxone 2 g IV 12 hourly/ Cefotaxime 2 g IV 4-6 hourly
10-14 days treatment
|
Chloramphenicol if patient is allergic to penicillin
|
Antibiotics should be started as soon as the possibility of bacterial
meningitis becomes evident, ideally within 30 minutes. Do not wait for CT
scan or LP results
|
Brain abscess, Subdural empyema
|
Streptococci, Bacteroides, Enterobacteria-ceae, S.aureus
|
Ceftriaxone 2 gm IV 12hourly or Cefotaxime 2 gm IV 4-6hourly
AND
Metronidazole 1 gm IV 12 hourly
Duration of treatment to be decided by clinical & radiological
response, minimum two months required.
|
Meropenem 2gm IV 8hourly
|
Exclude TB, Nocardia, Aspergillus, Mucor
|
Cardio-Vascular System Infections
|
||||
Infective Endocarditis
|
Viridans Streptococci, other Streptococci, Enterococci
|
Penicillin G 20MU IV divided doses, 4 hourly
or
Ampicillin 2 gm iv 4h AND Gentamicin 1mg/kg im or iv 8h
Duration: 4-6 weeks
|
Daptomycin 6 mg/kg IV once a day
Duration: 4-6 weeks
|
If patient is stable, ideally wait for blood cultures.
Guidance from Infectious disease specialist or clinical
microbiologist is recommended
|
Skin and Soft Tissue Infections
|
||||
Cellulitis
|
Streptococcus pyogenes (common), S.aureus
|
Amoxicillin Clavulanate 1.2 gm IV TDS/625 mg oral TDS
or
Ceftriaxone 2 gm IV OD
|
Clindamycin 600-900 mg IV TD
|
Treat for 5-7 days.
|
Furunculosis
|
S.aureus
|
Amoxicillin Clavulanate 1.2 gm IV/Oral 625 TDS or
Ceftriaxone 2 gm IV OD
Duration – 5-7 days
|
Clindamycin 600-900mg IV TDS
|
Get pus cultures before starting antibiotics
|
ANTIBIOTIC PRESCRIBING:
The antibiotic policy should also recommend good practices
of prescribing antibiotics. These include
1.
Before prescribing antibiotics appropriate investigations
for all suspected infections shall be ordered for
2.
All efforts shall be made to send micro-biological
samples before initiating anti-biotic therapy. The choice of antibiotic for presumptive
therapy should be based on the recommended antibiotics in this policy or based
on rapid tests , such as Gram stain
3.
Differentiation shall be made between
contamination, colonization and infection in a patient to prevent inappropriate
use of antibiotic.
4.
Antibiotic should not be prescribed as a habit
or for just in case infection is present. It should always be based on reasonable
clinical evidence of infection.
5.
Choice of antibiotic: Antibiotic should be
selected based upon antibiotic susceptibility of causative organism. Antibiotic
susceptibility is a report provided by microbiology which states percentage of
microorganism that can be killed by a specific antibiotic. Higher the
susceptibility, better will be the antibiotic in treating the infection. Other points
that should be considered while choosing an antibiotic are
6.
Review of antibiotic therapy – A daily review of
to assess the need of antibiotic therapy being given must be done. For most infections
5-7 days of antibiotic therapy should be sufficient. Simple UTI can be treated
in 3 days of antibiotics
7.
Presumptive therapy should start with a broad
spectrum antibiotic. Once culture reports are available, the doctor should step
it down to narrowest spectrum, most efficacious and most cost effective option.
RESERVE ANTIBIOTICS:
Selected few newer and more potent antibiotics shall be kept
as reserve antibiotics and the antibiotic policy shall put restrictions on
using them. The reserve antibiotics shall be made available after
recommendation from Microbiology department as per the culture report. The
antibiotics are kept reserve to maintain their efficacy in treating difficult
infections. Pharmacy shall be instructed to ascertain indications before
issuing reserve antibiotic to ward, and if indications are not met prescriber
should be requested to consult the Infection Control In-charge or the
Microbiology In-charge.
For example, Carbapenem and Linezolid, if kept as researve
antibiotic shall be used only if following criteria are fulfilled
1.
Severe sepsis as defined by more than one organ
failure of new onset
2.
Clinical failure of other classes of antibiotics
over 48 hours
3.
Underlying severe immuno-suppression –
Neutropeniea, immuno-suppressive therapy, Diabetic Ketoacidosis (DKA) etc
4. The organism is susceptible to only Carbapenems
/ Linezolid, as per culture report
DRUG HYPERSENSITIVITY
The antibiotic policy must state measures to prevent adverse
drug reactions. History of drug allergy should be taken from the patient before
initiating any antibiotic therapy. Responsibility should be clearly assigned on
who should ensure to get information of drug allergy.
If patients are unable to give an allergy history, the
doctor caring in the patient should take reasonable steps to contact someone
who can provide a reliable allergy history.
ALERT ANTIBIOTICS
Certain antibiotics are prone to be prescribed irrationally
or as a routine by doctors. They generally include ciprofloxacin, ceftazidime,
cefotaxime, ceftriaxone, vancomycin (or teicoplanin), imipenem, levofloxacin,
meropenem and moxifloxacin. Collectively, these are among the drugs most
frequently prescribed irrationally which is largely responsible for the current
escalation of antibiotic costs. They also account for a significant proportion
of serious antibiotic toxicity including Clostridium difficile diarrhoea and
CNS toxicity/seizures as well as the emergence of major antimicrobial
resistance. Safer, cheaper and equally effective alternatives are often available
which allow such agents to be kept in reserve for occasions when there are
clear cut microbiological indications.
Antibiotic Policy must therefore list out such antibiotics as ‘Alert
antibiotics’ and ensure that they are prescribed only on the recommendation of
senior medical doctor or after discussion with the Clinical Microbiologist or Infection
Control In-charge.
