TABLE 1.
Summary of ciprofloxacin-resistant S. pneumoniae isolates collected as part of CROSS between 1997 and 2005 and the resistance mechanisms present in ciprofloxacin-resistant isolatesa
| Study yr (no. of isolates) | All isolates (n = 10,657)b
|
CIP-resistant isolates (n = 205)c
|
|||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rate (%) of bacterial resistance
|
n | % of QRDR genotype in
|
% of efflux | ||||||||||||||||||
| CIP
|
GAT | GEM | LVX | MOX | MDR | Isolates with no mutations | ParC | Isolates with ParC and GyrA | |||||||||||||
| Age distribution
|
Geographic distribution
|
||||||||||||||||||||
| Overall | <16 yr old (n = 2,057) | 16-64 yr old (n = 4,637) | >64 yr old (n = 3,963) | British Columbia (n = 1,019) | Alberta (n = 1,466) | Saskatchewan (n = 1,168) | Manitoba (n = 1,321) | Ontario (n = 2,330) | Quebec (n = 2,017) | Maritimes (n = 1,336) | |||||||||||
| 1997-1998 (1,152) | 0.6 | 0.0 | 0.2 | 1.4 | 0.7 | 1.1 | 0.0 | 0.8 | 0.0 | 0.9 | 0.4 | NT | NT | 0.2 | 0 | 0.0 | 4 | 25.0 | 25.0 | 50.0 | 50.0 |
| 1998-1999 (1,256) | 1.5 | 0.0 | 1.7 | 2.3 | 1.4 | 0.5 | 1.0 | 0.7 | 1.5 | 2.9 | 1.2 | NT | NT | 0.5 | 0.3 | 0.1 | 14 | 7.1 | 57.1 | 35.7 | 28.6 |
| 1999-2000 (1,511) | 1.5 | 0.3 | 0.7 | 3.3 | 3.4 | 0.7 | 2.2 | 1.7 | 0.9 | 1.5 | 1.0 | 0.6 | 0.4 | 0.9 | 0.2 | 0.1 | 22 | 9.1 | 27.3 | 35.7 | 22.7 |
| 2000-2001 (1,402) | 1.7 | 1.1 | 1.7 | 2.0 | 1.5 | 1.1 | 0.7 | 0.7 | 1.7 | 1.5 | 5.3 | 0.6 | 0.5 | 0.6 | 0.4 | 0.3 | 21 | 19.1 | 19.1 | 52.4 | 33.3 |
| 2001-2002 (1,546) | 1.7 | 0.0 | 1.5 | 2.5 | 1.4 | 3.1 | 0.7 | 2.2 | 1.6 | 1.5 | 1.4 | 1.0 | 0.1 | 1.2 | 0.1 | 0.1 | 21 | 14.3 | 14.3 | 71.4 | 14.3 |
| 2003 (1,279) | 2.3 | 0.5 | 1.5 | 3.8 | 2.0 | 1.1 | 0.0 | 5.5 | 2.6 | 1.9 | 2.7 | 0.8 | 0.3 | 1.4 | 0.3 | 0.5 | 31 | 3.2 | 19.4 | 77.4 | 16.1 |
| 2004 (1,290) | 3.7 | 0.0 | 2.9 | 6.3 | 1.1 | 2.5 | 2.7 | 5.2 | 3.7 | 6.3 | 1.6 | 1.6 | 0.7 | 1.9 | 0.5 | 0.2 | 43 | 9.3 | 27.9 | 60.5 | 18.6 |
| 2005 (1,221) | 4.2 | 1.0 | 2.9 | 7.6 | 4.3 | 5.1 | 0.6 | 3.6 | 4.9 | 4.2 | 6.5 | 1.6 | 1.0 | 1.1 | 1.0 | 0.3 | 49 | 24.5 | 24.5 | 49.0 | 18.8 |
| P value (1997-1998 vs 2005) | <0.0001 | 0.16 | 0.0011 | <0.0001 | d | d | d | d | d | d | d | 0.04e | 0.11e | 0.008 | 0.0005 | 0.13 | 1.0 | 1.0 | 1.0 | 0.19 | |
CIP, ciprofloxacin; GAT, gatifloxacin; GEM, gemifloxacin; LVX, levofloxacin; MOX, moxifloxacin; MDR, multidrug resistant (includes resistance to penicillin, ciprofloxacin, and a macrolide, tetracycline, or trimethoprim-sulfamethoxazole); NT, not tested.
Includes all S. pneumoniae isolates collected, where n indicates specific numbers of isolates for overall, age and geographic distribution, and fluoroquinolone resistance rates.
Ciprofloxacin-resistant S. pneumoniae isolates, excluding S. pneumoniae isolates that may have undergone interspecies recombination.
Statistical analysis not included due to large yearly fluctuations.
Statistical analysis between 1999 to 2000 and 2005.