[Bacterial resistance to antibiotics in gram-negative rods isolated from intensive care units. Comparative analysis between two periods (1998 and 2001)].

The incidence and drug susceptibility of gram-negative isolates from clinical samples of patients from different intensive care units at the Hospital de Clinicas José de San Martín were analysed. Two hundred isolates during the same five months period, in two different years (1998 and 2001) were obtained and evaluated. Acinetobacter spp., was the most frequently isolated microorganism. Resistance to imipenem was observed in 60% of these isolations while resistance to 3rd generation cephalosporin and ciprofloxacin was observed in more than 80%. Klebsiella pneumoniae was not resistant to imipenem, the resistance to 3rd and 4th generation cephalosporins decreased from 71.4 to 30% of isolates (p < 0.05), while ciprofloxacin resistance increased from 5 to 20% (p < 0.05). An increasing resistance to imipenem in Pseudomonas aeruginosa was noted, from 15.4 to 68% (p < 0.05%); to ciprofloxacin, from 31.4 to 66.3% (p < 0.05); to amikacin, from 23 to 60.1% (p < 0.05); and to ceftazidime, from 8.2 to 28.3% (p < 0.05). In conclusion, the alarming rates of resistance found in this study provide compelling evidence of the need for more rational use of antimicrobial agents; ongoing surveillance on the etiology of infections and their resistance profiles is important to guide future antimicrobial chemotherapy.