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Prevalence of micro-organisms responsible for ventilator-associated bacterial pneumonia among patients in intensive care unit of a hospital in Madrid. Comparison with a multicentre study

Abstract number: P1659

Martínez M.C., Buendía B., Moreno M.J., Agudo S., López-Brea M.

Objective: To study the most prevalent microorganisms isolated in patients with mechanical ventilation of ICUs in Hospital Universitario de la Princesa during a period of six month and compare it with a multicentric epidemiological study (ENVIN-UCI: Estudio Nacional de Vigilancia de Infección Nosocomial en Servicios de Medicina Intensiva) realized in more than one hundred ICUs from hundreds of Spanish hospitals in the years 2006, 2007 and 2008.

Methods:149 purulent tracheobronquial secretion removed by bronchoaspirate from patients with ventilator-assiated pneumonia (VAP) – in accordance with the criterias of ventilator-associated pneumonia – were processed by quantitative culture techniques in blood agar and chocolate agar and incubated at 37°C in O2 and CO2 atmosphere respectively until 48hs. Gram stain was realized to begin an empirical antibiotic therapy. Identification of microorganism was performed by MicroScan of Siemens and antibiotic susceptibility by microdilution.

Results: From 365 patients admitted in ICU from March to August of Hospital Universitario de la Princesa, we had 149 isolated from 60 patients with ventilator-associated pneumonia. The most prevalent microorganisms in ICU of Hospital Universitario de la Princesa, compared with the multicentric epidemiological study, are listed in the table.

The most prevalent microorganism isolated in bronchoaspirate has been MSSA, with a percentage similar to the multicentric study, followed by Pseudomonas aeruginosa. We can probe Pseudomonas aeruginosa has a significant reduction in his prevalence, compared to multicentric study, and this percentage is slightly lower than MSSA. Furthermore, the rest of the microorganisms isolated are so different from the total epidemiological study.

Conclusion:The primary organisms responsible for VAP include Pseudomonas aeruginosa, Staphylococcus aureus and Enterobacteriaceae. However, precentage of aetiologies differs considerably between intensive care units.

We have proved Acinetobacter baumannii is lower in our hospital than in the rest of Spanish hospital included in ENVIN-UCI, where this microorganism is one of the most prevalent Gram-negative rod isolated. In our hospital Acinetobacter baumannii has suffered a considerable reduction in its prevalence in the last years. The significant morbidity and mortality associated with VAP require early konwledge of the prevalence of the microrganisms responsible of it in our ICUs to select appropriate empirical therapy.

MicroorganismH.U.de la Princesa'sENVIN-UCI
 UCI200620072008
MSSA12.75%11.81%12.50%11.27%
Pseudomonas aeruginosa12.08%16.90%17.55%18.63%
Stenotrophomonas maltophilia8.05%2.34%4.21%4.98%
MRSA7.38%7.42%4.09%3.58%
Haemophilus influenzae7.38%5.91%5.17%6.28%
Enterobacter aerogenes6.71%1.37%1.44%1.63%
Escherichia coli6.04%6.73%7.21%7.58%
Streptococcus pneumoniae4.03%2.34%2.64%2.23%
Acinetobacter baumannii2.68%12.77%11.78%8.99%

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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