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Table 2 Summary of antimicrobial co-resistance rates determined for a) E . coli, b) K . pneumoniae, c) K . oxytoca, d) E . cloacae, and e) P . aeruginosa

From: Antimicrobial co-resistance patterns of gram-negative bacilli isolated from bloodstream infections: a longitudinal epidemiological study from 2002–2011

a) E. coli       
No. of isolates (n) Resistance to Co-resistance rate with antibiotic (%)
2002-06   Ceftriaxone Ciprofloxacin Pip-tazo TMP-SMX Tic-clav
44 Ceftriaxone   73 14 59 59
194 Ciprofloxacin 16   8 62 31
3 Pip-tazo 33 67   67 nd
193 TMP-SMX 13 63 8   31
91 Tic-clav 29 67 nd 66  
2007-11       
146 Ceftriaxone   73 18 72 48
357 Ciprofloxacin 30   10 58 26
28 Pip-tazo 57 71   79 nd
373 TMP-SMX 28 56 10   27
64 Tic-clav 42 61 nd 61  
2002-11       
190 Ceftriaxone   73 18 69 53
551 Ciprofloxacin 25   10 60 29
31 Pip-tazo 55 71   77 nd
566 TMP-SMX 23 58 9   30
155 Tic-clav 34 65 nd 64  
b) K. pneumoniae       
No. of isolates (n) Resistance to Co-resistance rate with antibiotic (%)
2002-2011   Ceftriaxone Ciprofloxacin Pip-tazo TMP-SMX Tic-clav
20 Ceftriaxone   60 35 83 53
54 Ciprofloxacin 22   22 46 29
10 Pip-tazo 60 50   40 nd
44 TMP-SMX 30 57 16   37
19 Tic-clav 26 58 nd 53  
c) K. oxytoca       
No. of isolates (n) Resistance to Co-resistance rate with antibiotic (%)
2002-2011   Ceftriaxone Ciprofloxacin Pip-tazo TMP-SMX Tic-clav
8 Ceftriaxone   38 20 25 50
5 Ciprofloxacin 60   0 20 25
2 Pip-tazo 50 0   0 nd
5 TMP-SMX 40 20 0   100
3 Tic-clav 67 33 nd 33  
d) E. cloacae       
No. of isolates (n) Resistance to Co-resistance rate with antibiotic (%)
2002-2011   Ceftriaxone Ciprofloxacin Pip-tazo TMP-SMX Tic-clav
43 Ceftriaxone   26 47 37 81
17 Ciprofloxacin 65   17 59 91
9 Pip-tazo 100 11   11 nd
24 TMP-SMX 67 42 6   80
33 Tic-clav 67 30 nd 24  
e) P. aeruginosa       
No. of isolates (n) Resistance to Co-resistance rate with antibiotic (%)
2002-2011   Ceftazidime Ciprofloxacin Pip-tazo Imipenem Gentamicin
11 Ceftazidime   45 50 27 9
22 Ciprofloxacin 23   24 23 23
6 Pip-tazo 83 67   33 33
13 Imipenem 23 38 18   23
9 Gentamicin 11 56 29 33  
  1. Co-resistance rates were analyzed as a summary of isolates from 2002–2011 except for E. coli, where it was possible to analyze two time periods from 2002–06 and 2007–11 due to higher isolate numbers. Co-resistance rates are rounded to the nearest percent, and those that are ≥50% are highlighted in bold font. Note: Pip-tazo is piperacillin-tazobactam, TMP-SMX is trimethoprim-sulfamethoxazole, Tic-clav is ticarcillin-clavulanate; nd is not determined as isolates did not consistently have both Pip-tazo and Tic-clav susceptibilities reported.