Control of Acinetobacter baumannii infections: a before after study in a general Intensive Care Unit

Background: Acinetobacter baumannii (A baumannii) is an increasingly problematic healthcare-associated pathogen, especially in critical care units in Argentina.

Objective: to reduce healthcare associated infections (HCAI) caused by A. baumannii at the intensive care unit (ICU) and to evaluate the genetic relationship among the specimens.

Methods: this is a quasi-experimental non-controlled before-after study based on a behavioral intervention.
Setting: an eight bed ICU for general acute patients. The hospital has an Infection Control team and alcohol for hand hygiene is promoted since 2006. Alcohol availability was controlled monthly since October 2007.
This study had three periods:
1.    The pre-intervention period of surveillance of HCAI at the ICU: May 1^st of 2007 to May 31^st2008.
2.    The intervention: from December 2007 to May 2008. A bundle of activities started in May 2008: ventilator pneumonia prevention bundle (IHI bundle), contact precaution for those patients with A. baumannii positive cultures, a hand hygiene campaign, hand hygiene surveillance and a new cleaning schedule of the patient’s unit.
3.    Post-intervention period: 1^st June 2008 to 31^st July 2009. HCAI and hand hygiene surveillance was continued.
Surveillance was performed under NHSN criteria and monthly reports were given to the ICU staff
Genotyping method: A baumannii positive samples were genotyped. Fingerprinting using the BOX-A1R and ERIC primer was used. Differences were identified following criteria established by Tennover et al.
Cultures were performed under Clinical and Laboratory Standards Institute (CLSI) guidelines. Fisher exact test was done to compare HCAI during pre-intervention period to HCAI during post-intervention period.

Results:

A total of 2022 patient days were included in the surveillance of the ICU during the pre-intervention period of twelve month and 2106 patient days during the post-intervention period of fourteen month. Ventilator associated pneumonia (VAP) caused by A baumannii were 7/1284 ventilator days (5.45 ‰) and catheter bloodstream infections (CBI) were 3/1726 central-line days (1.74 ‰). Only one A baumannii catheter associated bacteremia was detected during the second period 1/1764 (0.57 ‰) (p: 0.37) and no ventilator associated pneumonia was detected (p: 0.03). Forty eight A baumannii samples corresponding to infections and colonization were genotyped. The method didn’t identify more than one fingerprint pattern.

Conclusions: Results indicate that a bundle of interventions was effective to reduce VAP caused by A baumannii and the effect on CBI was not statistically significant but there is a decreasing trend.
The genetic relationship deducted from the rep-PCR method didn´t distinguish more than one fingerprint pattern of A baumannii.
HCAI are still over NHSN limits of benchmarking which is the next goal to achieve.