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Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán

2003, Number 3

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Rev Biomed 2003; 14 (3)

Clinically relevant bacteria in mechanical ventilators and air conditioners in hospitals in San José, Costa Rica

Gamboa MM, Rodríguez E, Rojas M

Language: Spanish
References: 33
Page: 143-151
PDF size: 44.59 Kb.


ABSTRACT

Introduction. The risk of acquiring respiratory nosocomial infections, whose mortality rate can be as high as 76%, increases with the use of mechanical ventilators and air conditioning. Therefore, our goal was to detect clinically relevant bacteria in them in order to help to control such infections in Costa Rican hospitals.
Material and methods. In four hospitals, 120 samples of accumulated water from 79 mechanical ventilators and 41 air conditioners were analysed; each sample was concentrated by filtration, resuspended, and inoculated in suitable culture media. Isolates were identified using an API® semiautomated system and the sensitivity tests were done with the Kirby and Bauer method or ATB® strips.
Results. 80% of air conditioners and 53% of the mechanical ventilators were positive for clinically significant bacteria, resulting in 63% positive samples. Most of the isolates were Gram negative bacilli (73%), Pseudomonas and related genera were the most frequent (47%), showing the highest resistance to cephalothin (77%), the lowest to imipenem (6%), and an antimicrobial multiresistance of 64%. Staphylococcus was the most frequent gender of Gram positive cocci (84%), with the highest resistance to rifampicin (86%), the lowest to penicillin (25%), and an antimicrobial multiresistance of 50%; six strains (all coagulase negative) were vancomycin resistant.
Discussion. This high percentage of positive samples of clinically significant bacteria represents a risk for patients, especially those in intensive care and surgery units. The predominance of Gram negative bacteria tallies with to its importance in nosocomial pneumonia; its presence indicates contamination of the hospital environment or bad hygiene during the manipulation of the equipment. The high antimicrobial multirresistance found is worrying and should draw health authorities attention to it.


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