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Risk Factors for Recovery of Imipenem- or Ceftazidime-Resistant Pseudomonas aeruginosa Among Patients Admitted to a Teaching Hospital in Brazil

  • Carlos Magno C. B. Fortaleza (a1) (a2), Maristela P. Freire (a1), Djalma de C. Moreira Filho (a1) and Marcelo de Carvalho Ramos (a1)



The prevalence of resistance to imipenem and ceftazidime among Pseudomonas aeruginosa isolates is increasing worldwide.


Risk factors for nosocomial recovery (defined as the finding of culture-positive isolates after hospital admission) of imipenem-resistant P. aeruginosa (IRPA) and ceftazidime-resistant P. aeruginosa (CRPA) were determined.


Two separate case-control studies were conducted. Control subjects were matched to case patients (ratio, 2:1) on the basis of admission to the same ward at the same time as the case patient. Variables investigated included demographic characteristics, comorbid conditions, and the classes of antimicrobials used.


The study was conducted in a 400-bed general teaching hospital in Campinas, Brazil that has 14,500 admissions per year. Case patients and control subjects were selected from persons who were admitted to the hospital during 1992–2002.


IRPA and CRPA isolates were obtained from 108 and 55 patients, respectively. Statistically significant risk factors for acquisition of IRPA were previous admission to another hospital (odds ratio [OR],4.21 [95% confidence interval {CI}, 1.40-12.66];P = .01), hemodialysis (OR, 7.79 [95% CI, 1.59-38.16]; P = .01), and therapy with imipenem (OR, 18.51 [95% CI, 6.30-54.43]; P<.001), amikacin (OR, 3.22 [95% CI, 1.40-7.41]; P = .005), and/or vancomycin (OR, 2.48 [95% CI, 1.08-5.64]; P = .03). Risk factors for recovery of CRPA were previous admission to another hospital (OR, 18.69 [95% CI, 2.00-174.28]; P = .01) and amikacin use (OR, 3.69 [95% CI, 1.32-10.35]; P = .01).


Our study suggests a definite role for several classes of antimicrobials as risk factors for recovery of IRPA but not for recovery of CRPA. Limiting the use of only imipenem and ceftazidime may not be a wise strategy to contain the spread of resistant P. aeruginosa strains.


Corresponding author

Departamento de Doencas Tropicais, Faculdade de Medicina de Botucatu, Distrito de Rubiao Junior, Botucatu, São Paulo, Brazil—CEP 18618-970. PO BOX 530, (


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1.Sader, HS, Gales, AC, Pfaller, MA, et al. Pathogen frequency and resistance patterns in Brazilian hospitals: summary of results from three years of the SENTRY Antimicrobial Surveillance Program. Braz J Infect Dis 2001; 5:200214.
2.Sader, HS, Jones, RN, Gales, AC, et al. SENTRY Antimicrobial Surveillance Program report: Latin American and Brazilian results for 1997 through 2001. Braz J Infect Dis 2004; 8:2579.
3.National Nosocomial Infection Surveillance (NNIS) system report, data summary from January 1992 through June 2003, issued August 2003. Am J Infect Control 2003; 31:481498.
4.Harris, AD, Smith, D, Johnson, JA, Bradham, DD, Roghmann, MC. Risk factors for imipenem-resistant Pseudomonas aeruginosa among hospitalized patients. Clin Infect Dis 2002; 34:340345.
5.Harris, AD, Karchmer, TB, Carmeli, Y, Samore, MH. Methodological principles of case-control studies that analyzed risk factors for antibiotic resistance: a systematic review. Clin Infect Dis 2001; 32:10551061.
6.Organização Mundial da Saude. Classificação estatística internacional de doenças. São Paulo, Brasil: EDUSP, 2004.
7.Charlson, ME, Pompei, P, Ales, KL, MacKenzie, CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 1987; 40:373383.
8.Lipsitch, M, Samore, MH. Antimicrobial use and antimicrobial resistance: a population perspective. Emerg Infect Dis 2002; 8:347354.
9.Muder, , RR, , Brennen, C, Drenning, SD, Stout, JE, Wagener, MM. Multiply antibiotic-resistant gram-negative bacilli in long-term care facility: a case-control study of patient risk factors and prior antibiotic use. Infect Control Hosp Epidemiol 1997; 18:809813.
10.Cailleaux, V, Mulin, B, Capellier, G, Juliot, MC, Thouverez, M, Talon, D. Epidemiological study of variations in beta-lactam antibiotic susceptibility of Pseudomonas aeruginosa in two intensive-care units. J Hosp Infect 1997; 37:217224.
11.Troillet, N, Samore, MH, Carmeli, Y. Imipenem-resistant Pseudomonas aeruginosa: risk factors and antibiotic susceptibility patterns. Clin Infect Dis 1997; 25:10941098.
12.Harris, AD, Samore, MH, Lipsitch, M, Kaye, KS, Perencevich, E, Carmeli, Y. Control-group selection importance in studies of antimicrobial resistance: examples applied to Pseudomonas aeruginosa, enterococci, and Escherichia coli. Clin Infect Dis 2002; 34:15581563.
13.Cao, B, Wang, H, Sun, H, Zhu, Y, Chen, M. Risk factors and clinical outcomes of nosocomial multidrug resistant Pseudomonas aeruginosa infections. J Hosp Infect 2004; 57:112118.
14.Quinn, JP, Dudek, EJ, DiVicenzo, CA, Lucks, DA, Lerner, SA. Emergence of resistance to imipenem during therapy for Pseudomonas aeruginosa infection. J Infect Dis 1986; 154:289294.
15.Carmeli, Y, Troillet, N, Eliopoulos, GM, Samore, MH. Emergence of antibiotic-resistant Pseudomonas aeruginosa: comparison of risks associated with different antipseudomonal agents. Antimicrob Agents Chemother 1999; 43:13791382.
16.Defez, C, Fabbro-Peray, P, Bouziges, N, et al. Risk factors for multidrug-resistant Pseudomonas aeruginosa nosocomial infection. J Hosp Infect 2004; 57:209216.
17.Paramythiotou, E, Lucet, JC, Timsit, JF, et al. Acquisition of multidrug-resistant Pseudomonas aeruginosa in patients in intensive care units: role of antibiotics with antipseudomonal activity. Clin Infect Dis 2004; 38:670667.
18.Lee, SC, Fung, CP, Liu, PYK, et al. Nosocomial infections with ceftazidime-resistant Pseudomonas aeruginosa: risk factors and outcome. Infect Control Hosp Epidemiol 1999; 20:205207.
19.El Amari, EB, Chamot, E, Auckenthaler, R, Pechère, JC, Van Delden, C. Influence of previous exposure to antibiotic on the susceptibility patter of Pseudomonas aeruginosa bacteremic isolates. Clin Infect Dis 2001; 33:18591864.
20.Ferreira, ACB, Gobara, S, Costa, SF, et al. Emergence of resistance in Pseudomonas aeruginosa and Acinetobacter species after the use of antimicrobials for burned patients. Infect Control Hosp Epidemiol 2004; 25: 868-872.
21.Gales, AC, Menezes, LC, Silbert, S, Sader, HS. Dissemination in distinct Brazilian regions of an epidemic carbapenem-resistant Pseudomonas aeruginosa producing SPM metallo-beta-lactamase. J Antimicrob Chemother 2003; 52:699702.


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