Acinetobacter baumannii is a bacteria that has become increasingly drug-resistant and causes a variety of infections, especially in hospital settings. It emerged as a significant pathogen among soldiers during the Iraq war. Identification requires specialized laboratory techniques, but molecular testing provides the most accurate identification. Treatment options are limited due to high resistance rates, but carbapenems and sulbactam are still used. Preventing transmission relies on good hand hygiene and environmental cleaning.

1. Acinetobacter baumannii
an update
Dr.T.V.Rao MD
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 1

2. Recent History of
Acinetobacter
baumannii
• The bacteria made a large
resurgence in the early Iraq
war. Many soldiers injured
in Afghanistan and the
Iraq/Kuwait region showed
A. baumannii infections in
their bloodstreams, and
returning soldiers showed
debilitating soft tissue
infection
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 2

3. Learning from
Iraq War
• In outpatients fatal
pneumonia were described
by Acinetobacter after use
no more effective antibiotics.
Severe wound infection and
multidrug-resistant
Acinetobacter baumannii by
Osteomyelitis were
diagnosed among American
soldiers who had been
wounded in combat
operations in Iraq and
Afghanistan.7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 3

4. Acinetobacter
baumannii a Important
Hospital associated
Infection
• Acinetobacter baumannii has
evolved as a hospital pathogen,
due in part to excessive and
inappropriate use of antibiotics.
Its transmission has been
associated with war, natural
disasters, and just about any
other instance where one
observes an influx in hospital
trauma admissions and increased
transfer of patients and staff
from one hospital to the next
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 4

5. Acinetobacter
baumannii becoming a
Superbug
• Increasing carbapenem
resistance among
Acinetobacter species is
particularly troubling,
because it is very often
associated with multidrug
resistance and because it is
occurring in the context of
increases in the incidence of
Acinetobacter infection
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 5

6. Acinetobacter
baumannii is …..
• Acinetobacter baumannii is a
small, rod-shaped, opportunistic
bacteria. This pathogen
generally affects people with
compromised immune systems,
especially those in hospital
settings like intensive care units.
This bacteria, like many other
species, has become increasingly
resistant to all forms of
antibiotics7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 6

7. A. baumannii has
several methods that it
uses to be an effective
pathogen
• Beta-lactamase, an enzyme
that breaks down penicillin.
• Resistance islands, genes
that encode more enzymes
to block other classes of
antibiotics.
• biofilm formation, a sort of
protective covering that
makes antibiotics unable to
get into the bacteria.
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 7

8. Effect of A. baumannii
can make one a
carrier
• Full infections are rare in
healthy people.
Nevertheless, A.
baumannii can still
colonize a healthy person,
though they show no
symptoms. People who are
asymptotically colonized
are called carriers, as they
can spread it to others.
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 8

9. How A. baumannii Spreads
• This primarily occurs in person-
to-person contact (physically
touching) or through
contaminated surfaces in a
hospital. Additionally, these
bacteria can live on a person's
skin, and even in a clean
environment (such as a clean
counter top) for many days
before dying.
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 9

10. Acinetobacter
baumannii causes many
ailments, including:
• infection of the blood
(sepsis),
• infection of the skin
and muscle,
• pneumonia,
• meningitis, and even
• urinary tract
infection.
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 10

11. Identification at
Resource poor
laboratories
• The differentiation in routine
laboratories is based on the
metabolic activities. However, the
precise differentiation of the
species with standard methods is
often not possible. Therefore,
four Genomospecies were
summarized for Acinetobacter
baumannii Acinetobacter
calcoaceticus complex.
Acinetobacter species can
ferment glucose and thus do not
belong to the so-called "non-
fermenters7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 11

12. Acinetobacter
Genus identification
• Acinetobacter is gram negative and in
the coccobacillus form when in its
stationary phase but can be rod-
shaped during periods of rapid
growth. It is oxidase negative, indole
negative, catalase positive, and
hemolytic. Acinetobacter can be
cultured on routine laboratory media
due to its ability to use various
sources of nutrition and will grow at
44°C. These standard laboratory
techniques will identify the genus but
will not identify the species.
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 12

13. Automation gives
more precise
Identification
• There are automated
methods available
today to quickly and
accurately identify an
isolate at the species
level
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 13

14. Newer Methods to
Identify A baumannii
• These methods are phenotypic,
utilizing biochemistry and
assimilation tests usually done
manually to identify the genus
and species of bacteria in less
time. To identify an A. baumannii
isolate, a couple of analyzers that
could be used are Microscan
WalkAway (Dade Behring, West
Sacramento, CA) and Vitek 2
(bioMérieux, Marcy l'Etoile,
France).
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 14

15. Automation helps In
Antibiotic Sensitivity
testing too
• However, while these analyzers
will identify the isolate as A.
baumannii, they are really only
identifying the A. baumannii
complex, but these analyzers
have the added benefit of
automated susceptibility
testing to guide the physician in
making appropriate treatment
decisions.
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 15

16. Molecular Testing Methods for Identification
• Another method of
identification is molecular
testing. Molecular testing
can identify an isolate down
to the genotype. A couple of
molecular methods used in
laboratories today are
pulsed-field gel
electrophoresis (PFGE) and
16s rRNA sequencing.
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 16

17. Why We Need
Molecular Methods
• These molecular methods
are not only useful in
identifying causes of
bacterial infection, but they
can aid a hospital in its
infection control measures,
highlighting areas of
weakness, and can identify
the source of hospital-
acquired infections.
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 17

18. Pulsed-field gel
electrophoresis
• Pulsed-field gel
electrophoresis is a
type of gel
electrophoresis used
to separate large
molecules of DNA up
to 2000 kb. This
procedure uses 3
electric fields instead
of 1
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 18

19. Emerging Molecular
Methods
• A second molecular method
employed in bacterial
identification is 16s ribosomal
DNA (rDNA) sequencing. In this
method, DNA is isolated from
bacterial colonies and
amplified with primers
selective for the 16s rDNA. The
rDNA can then be sequenced
and results can be compared
to Acinetobacter genotypes on
public-domain sequence
databases such as GenBank.
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 19

20. Acinetobacter Baumannii therapy
• The agent of choice are carbapenems [imipenem
(ZIENAM), meropenem (MERONEM)] is recommended.
However, differences in sensitivity may exist with respect
to the two substances, ie with proven sensitivity to
imipenem may not be automatically inferred on sensitivity
to meropenem and vice versa. As a further treatment
option has recently become doripenem are available.
However, the frequency of resistance to carbapenems in
recent years has increased significantly worldwide.
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 20

21. Beta-lactamase
inhibitors
• Beta-lactamase inhibitors,
especially sulbactam
(COMBACTAM), possess
intrinsic activity against
Acinetobacter baumannii. The
sulbactam monotherapy is not
recommended for serious
infections. The combination
with a Betalaktamantibiotikum
no increase in activity appears
to result..
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 21

22. Tigecycline has bacteriostatic activity against
multidrug-resistant Acinetobacter.
• Tigecycline has
bacteriostatic activity
against multidrug-
resistant Acinetobacter.
However, the
development of
resistance during therapy
is possible. Against this
background, tigecycline is
rather to be regarded as a
reserve substance here.
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 22

23. Colistin in Drug
Resistant strains
• As therapeutic
alternatives, the
aminoglycosides come
(in combination with
another active
antibiotic) into
consideration. Colistin
is used for treating
infections caused by
pan-resistant strains.
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 23

24. Prevention with
Hand Washing
• The key to reducing A.
baumannii infections is to
control contact with patients
using hand hygiene. Hand
hygiene has been shown in many
studies to be the most protective
factor that any provider can do
to prevent transmission of
infectious agents to their
patients.7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 24

25. Hand Washing most
effective to stop spread of
Drug Resistant Bacteria
• Simply running their
hands under water and
with a small amount of
soap can vastly
decrease the risk of
transmission. This tactic
has shown marked
drops in infection rates
since the early 19th
century.
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 25

26. Environmental
Cleansing
• The next most logical and
effective method is
environmental cleansing, which
takes the form of sterilizing
surfaces and equipment. High-
grade cleaning agents such as
bleach can destroy the outer
coating of the bacteria.
However, to truly sterilize
equipment like surgical
instruments, high pressure and
heat are needed.
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 26

27. Practice Hand Washing Save
many Lives
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 27

28. References
• A Review of Acinetobacter baumannii as a Highly Successful Pathogen
in Times of War Callie Camp, MS, MT(ASCP)CM; Medscape resource
Infectious diseases
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 28

29. •Program Created by Dr.T.V.Rao MD for benefit of
Medical and Paramedical Professionals for Global
resources on Infectious diseases
Email
doctortvrao@gmail.com
7/7/2017 Dr.T.V.Rao MD @Acinetobacter baumannii 29