The seminar is about this article: Containment of a Methicillin-resistant Staphylococcus aureus outbreak in a Neonatal Intensive Care Unit. I described

1. NATALIA LORENZO GONZALEZ

2. Staphylococcus
vs
Streptococcus
They are two
medically
important genera
of gram-positive
cocci.
Both are
nonmotile and do
not form spores.
Microscopically,
staphylococci
appear in
grapelike clusters,
whereas
streptococci are in
chains.
Biochemically,
staphylococci
produce catalase
(an important
virulence factor),
whereas
streptococci do
not.
Review of Medical Microbiology & Immunology: A Guide to Clinical Infectious Diseases, 15e,Warren
Levinson, Peter Chin-Hong, Elizabeth A. Joyce, Jesse Nussbaum, Brian Schwartz.2018.

3. The action of antimicrobial agents
on a range of targets within the
bacterial cell can result in
inhibition of bacterial growth or in
killing of the bacterial cell.
Reduction in or loss of an agent’s
antibacterial effect is referred to
as resistance, and the properties
of or alterations in the bacterium
that result in reduced
antimicrobial activity are
termed resistance mechanisms.
The β-lactam antibiotics
(penicillins, cephalosporins, ect)
share a common structure (β-
lactam ring) and mechanism of
action (inhibition of the
synthesis of the bacterial
peptidoglycan cell wall).
Methicillin is a example of
penicillins.
Resistance Methicillin
Malani, P. N. (2012). Harrison’s principles of internal medicine. JAMA, 308(17), 1813-1814.

4. Objectives
To describe an investigation and
containment of an Methicillin-
resistant Staphylococcus aureus
(MRSA) outbreak in a neonatal
intensive care unit (NICU).

5. Methods
Patients
• Rambam Health Care Campus is a tertiary
hospital in northern Israel.
• The unit was composed of three spaces:
- The main space had nine beds for
critically ill neonates.
- Two rooms with eight beds each served
intermediate care cases.
• The index case was an 8 day old term baby.
MRSA was isolated from his conjunctiva.

6. Epidemiology
• Infection control strategy
- Identifying MRSA positive
cases and strict isolation
using separate rooms and
contact precautions.
• Screening policy
- Samples were collected
using Amies swabs from
nares, axilla, groin, and anus
for each case.
- Re-education of infection
control measures and hand
hygiene was reinforced

7. PFGE
Pulsed-field gel electrophoresis is a
technique by which genomic DNA is
isolated from the organism of interest
followed by restriction enzyme
analysis.
• Basis  Evidence genetic
variability
• For what?  To evaluate the
presence of Staphylococcus in a
population
https://www.sciencedirect.com/topics/neuroscience/pulsed-field-gel-electrophoresis

8. Chlorhexidine
Water-soluble
chlorhexidine
digluconate is
used in water-
based
formulations as
an antiseptic.
Is slower in its
action than
alcohols, but,
because of its
persistence, it
has residual
activity.
Chlorhexidine is
not used for
premature
babies in our
institution due
to previous
reports of
toxicity.
Mupirocin
Is produced
by Pseudomonas
fluorescens
It is available as
an ointment for
topical
application.
This material
obstructs the
very small
nostrils and the
potential space
is too small for
any significant
instillation of
mupirocin
Wolff, K., & Johnson, R. A. (2009). Fitzpatrick's color atlas and synopsis of clinical dermatology. McGraw Hill.

9. Results
• Screening for MRSA from
other body sites was
positive from the eye,
nares, throat, and rectum
and negative for axilla and
groin.
• All patients, except the
index patient and another
one (patient #5) with mild
conjunctivitis, were
asymptomatic.

10. PFGE demonstrated
the same pattern for
all NICU patients,
although they were
different from that
of the PICU patients.

11. Discussion
Author What he says Yes or No
Song et al Estimated an increased length of stay and extra
charges of $164,301 per patient with infection
compared to those without MRSA.
X
Gerber et al Point out that nasal swabs are suffcient to detect
MRSA as a colonizer in the NICU.
Schultz and co-authors Tere was no difference in the cost of each hospi-
talization day, but the colonized patients had longer
hospitalization periods and the total excess cost was
$6,901,180.
X

12. Conclusions
• The screening for resistant bacterial is not the
best tool to prevent the negatives outcomes
of a critical infection by them, nevertheless it
could change the results in the time of
treatment on the NICU and aborting the fatal
outbreaks.
• Even thought the screening has no the best
sensibility of detection for the MRSA, an
active and protocolized screening can achieve
important results is a diminish in fatal
outcomes and treatment cost.

13. - Ryan, K. J., & Ray, C. G. (2004). Medical microbiology. McGraw Hill, 4, 370.
- Review of Medical Microbiology & Immunology: A Guide to Clinical Infectious Diseases, 15e,Warren Levinson, Peter Chin-
Hong, Elizabeth A. Joyce, Jesse Nussbaum, Brian Schwartz.2018.