Article Figures & Data
Figures
- Fig 1
Rates of intestinal colonization by imipenem-resistant gram-negative bacilli in intensive care patients. Bars indicate observed rates ± standard deviation (SD) (error bars).
- Fig 2
Dendrogram and rep-PCR fingerprints of Pseudomonas aeruginosa (a), Stenotrophomonas maltophilia (b), Klebsiella pneumoniae (c), and Acinetobacter baumannii (d).
Tables
- Table 1
Mechanisms of resistance and MICs for imipenem and ertapenem of 56 isolated imipenem-resistant Gram-negative bacilli
Species No. of strains Resistance mechanismsa MIC (mg/liter)b Enzymes Other Imipenem Ertapenem P. aeruginosa 19 OprD− 6–>32 ND 6 AmpC++ OprD− 16–>32 ND 4 OprD− MexAB efflux ++ 24–>32 ND 2 AmpC++ OprD− MexAB efflux ++ 24–32 ND 1 GES-9 OprD− >32 ND 4 VIM-2 >32 ND Enterobacteriaceae K. pneumoniae 2 DHA-1 OMP− 24–32 >32 1 TEM-1 CTX-M15 NP 3 >32 E. aerogenes 1 TEM-24 AmpC++ OMP− 16 >32 E. cloacae 1 SHV-12 AmpC++ OMP− 32 >32 H. alvei 1 AmpC++ NP 4 32 A. baumannii 2 6–12 ND S. maltophilia 12 Wild type ND ND - Table 2
Univariate and multivariate analysis of risk factors associated with intestinal colonization of imipenem-resistant Gram-negative bacillia
Characteristic or outcome No. of individuals or parameter value (%, unless range is specified) Univariate ORb Univariate Pc Multivariate ORd Carrier patients (n = 36) Controls (n = 36) Sociodemographic characteristics Age, yr [avg (range)] 58.3 (30–86) 59.9 (37–86) 0.57 Sex ratio (F/M)e 0.33 0.64 0.31 Characteristics at admission Type of ICU 1.00 Surgical 14 (38.9) 14 (38.9) 1.0 Medical 22 (61.1) 22 (61.1) 1.0 (0.3–2.9) Origin 0.69 Home 8 (22.2) 10 (27.8) 1.0 Hospital 27 (75.0) 24 (66.7) 1.4 (0.4–4.8) Other 1 (2.8) 2 (5.6) 0.6 (0.1–14.4) Cancer 2 (5.6) 2 (5.6) 1.0 (0.1–14.5) 1.00 HIV 3 (8.3) 4 (11.1) 0.7 (0.1–4.7) 1.00 Respiratory failure 7 (19.4) 3 (8.3) 2.6 (0.5–17.2) 0.31 Renal failure 6 (16.7) 1 (2.8) 6.8 (0.8–330.4) 0.11 Cardiac failure 3 (8.3) 4 (11.1) 0.7 (0.1–4.7) 1.00 Obesity 6 (16.7) 6 (16.7) 1.0 (0.2–4.2) 1.00 Pulmonary transplantation 3 (8.3) 2 (5.6) 1.5 (0.2–19.5) 1.00 Diabetes mellitus 4 (11.1) 5 (13.9) 0.8 (0.1–4.0) 1.00 Cirrhosis 2 (5.6) 2 (5.6) 1.0 (0.1–14.5) 1.00 McCabe scores 0.07 0 7 (19.4) 15 (41.7) 1.0 ≥1 29 (80.6) 21 (58.3) 2.9 (0.9–10.0) SAPS II [median (range)] 48.5 (13–120) 41 (13–104) 0.36 ESBL carriage 8 (22.2) 6 (16.7) 1.4 (0.4–5.7) 0.77 Surveillance period,f days [median (range)] 13.5 (3–52) 12.5 (3–52) 0.97 Antibiotic treatments Exposure time to antibiotics, days [median (range)] 11.5 (0–51) 9.0 (0–37) 0.84 Penicillin exposure 8 (22.2) 16 (44.4) 0.4 (0.1–1.1) 0.08 0.3 (0.1–0.8) Penicillin and β-lactamase inhibitor exposure 17 (47.2) 20 (55.6) 0.7 (0.3–2.0) 0.64 Cephalosporin exposure 20 (55.6) 17 (47.2) 1.4 (0.5–3.9) 0.64 Imipenem exposure 28 (77.8) 14 (38.9) 5.4 (1.8–17.8) <0.01 Days of imipenem exposure <0.01 0 8 (22.2) 22 (61.1) 1.0 1.0 1 to 3 10 (27.8) 6 (16.7) 4.4 (1.1–20.5) 5.9 (1.5–25.7) 4 to 21 18 (50.0) 8 (22.2) 6.0 (1.7–23.3) 7.8 (2.4–29.8) Fluoroquinolone exposure 9 (25.0) 8 (22.2) 1.2 (0.3–4.0) 1.00 Aminoglycoside exposure 25 (69.4) 21 (58.3) 1.6 (0.6–4.8) 0.46 Glycopeptide exposure 20 (55.6) 11 (30.6) 2.8 (1.0–8.4) 0.06 Metronidazole exposure 5 (13.9) 6 (16.7) 0.8 (0.2–3.6) 1.00 Macrolide exposure 5 (13.9) 3 (8.3) 1.8 (0.3–12.3) 0.71 Colistin exposure 5 (13.9) 2 (5.6) 2.7 (0.4–30.4) 0.43 Outcome ICU stay, days [median (range)] 33.5 (4–173) 15.5 (5–137) 0.14 Death 13 (36.1) 11 (30.6) 1.3 (0.4–3.9) 0.80 ↵a Imipenem-resistant Gram-negative bacilli including Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Enterobacteriaceae, and Acinetobacter baumannii.
↵b Odds ratios (ORs) are given with the 95% confidence intervals in parentheses.
↵c Bivariate analysis was performed using Pearson's chi-squared, Fisher's exact, Wilcoxon, or Welch test (α = 0.05).
↵d Variables with univariate P value of <0.15 were included for multivariate analysis, which was performed using descending stepwise logistic regression.
↵e F, female; M, male.
↵f Period of surveillance, period between admission and acquisition of imipenem-resistant Gram-negative bacilli.
- Table 3
Univariate and multivariate analysis of risk factors associated with intestinal colonization of imipenem-resistant Pseudomonas aeruginosa
Characteristic or outcome No. of individuals or parameter value (%, unless range is specified) Univariate ORa Univariate Pb Multivariate ORc Carrier patients (n = 22 (%) Controls (n = 22) Sociodemographic characteristics Age, yr [avg (range)] 57.3 (30–74) 60.9 (37–80) 0.28 Sex ratio (F/M)d 0.57 0.29 0.31 Characteristics at admission Type of ICU 1.00 Surgical 8 (36.4) 8 (36.4) 1.0 Medical 14 (63.6) 14 (63.6) 1.0 (0.2–4.1) Origin 1.00 Home 6 (27.3) 5 (22.7) 1.0 Hospital 16 (72.7) 17 (77.3) 0.8 (0.2–3.8) Other Cancer 1 (4.5) 2 (9.1) 0.5 (0.1–10.0) 1.00 HIV 3 (13.6) 1 (4.5) 3.2 (0.2–182.0) 0.61 Respiratory failure 5 (22.7) 2 (9.1) 2.9 (0.4–33.8) 0.41 Renal failure 3 (13.6) 1 (4.5) 3.2 (0.2–182.0) 0.61 Cardiac failure 2 (9.1) 3 (13.6) 0.6 (0.1–6.2) 1.00 Obesity 4 (18.2) 5 (22.7) 0.8 (0.1–4.2) 1.00 Pulmonary transplantation Diabetes mellitus 2 (9.1) 4 (18.2) 0.5 (0.1–3.6) 0.66 Cirrhosis 1 (4.5) 1 (4.5) 1.0 (0.1–82.1) 1.00 McCabe scores 0.12 0 5 (22.7) 11 (50.0) 1.0 1.0 ≥1 17 (77.3) 11 (50.0) 3.3 (0.8–15.8) 5.0 (1.1–29.0) SAPS II (median [range]) 55 (15–120) 41 (13–86) 0.05 ESBL carriage 3 (13.6) 5 (22.7) 0.5 (0.1–3.3) 0.70 Surveillance period,e days [median (range)] 13 (4–37) 13 (3–37) 0.91 Antibiotic treatments Exposure time to antibiotics, days [median (range)] 10.5 (2–23) 8.5 (0–37) 0.52 Penicillin exposure 6 (27.3) 8 (36.4) 0.7 (0.1–2.8) 0.75 Penicillin and β-lactamase inhibitor exposure 8 (36.4) 12 (54.5) 0.5 (0.1–1.9) 0.36 Cephalosporin exposure 13 (59.1) 12 (54.5) 1.2 (0.3–4.7) 1.00 Imipenem exposure 17 (77.3) 10 (45.5) 3.9 (0.9–18.9) 0.06 Days of imipenem exposure 0.09 0 5 (22.7) 12 (54.5) 1.0 1.0 1 to 3 8 (36.4) 6 (27.3) 3.1 (0.6–18.3) 5.3 (1.0–38.4) 4 to 21 9 (40.9) 4 (18.2) 5.1 (0.9–35.1) 6.8 (1.2–50.2) Fluoroquinolone exposure 6 (27.3) 4 (18.2) 1.7 (0.3–9.6) 0.72 Aminoglycoside exposure 14 (63.6) 12 (54.5) 1.4 (0.4–5.8) 0.76 Glycopeptide exposure 12 (54.5) 5 (22.7) 3.9 (0.9–18.9) 0.06 Metronidazole exposure 4 (18.2) 3 (13.6) 1.4 (0.2–10.9) 1.00 Macrolide exposure 2 (9.1) 1 (4.5) 2.1 (0.1–129.6) 1.00 Colistin exposure 4 (18.2) 2 (9.1) 2.2 (0.3–26.9) 0.66 Outcome ICU stay, days [median (range)] 27.5 (9–173) 15.0 (5–137) 0.25 Death 11 (50.0) 7 (31.8) 2.1 (0.5–8.8) 0.36 ↵a ORs are given with the 95% confidence intervals in parentheses.
↵b Bivariate analysis was performed using Pearson's chi-squared, Fisher's exact, Wilcoxon, or Welch test (α = 0.05).
↵c Variables with univariate P value of <0.15 were included for multivariate analysis, which was performed using descending stepwise logistic regression.
↵d F, female; M, male.
↵e Period of surveillance, period between admission and acquisition of imipenem-resistant P. aeruginosa.
