Antimicrobial Susceptibility Survey: RESULTS
From 650 cultures that were received from participating centers, 554 (85.2%) were recovered on subculture and subsequently confirmed as P aeruginosa. All of the 554 isolates that were confirmed as P aeruginosa produced pyocyanin. Ninety-six of 554 (17.3%) of the isolates were recovered from the ICU, and 10.1% (56/554) from the nursery. Other inpatients services accounted for 288 isolates (52.0%%) and community isolates of P aeruginosa accounted for only 20.6% (114/554) of all isolates (Table 1). Respiratory tract isolates were the predominant source of P aeruginosa from the ICU and the nursery, whereas wounds were the principal source from other inpatients. More than 98% (112/114) of the community isolates of P aeruginosa were recovered from ear and urinary tract infections.
Table 1. Proportion (%)* of Pseudomonas aeruginosa Strains Recovered from Various Sources in Relation to Patient Category
| Patient Category From | |||||||
| Source |
ICU1 |
Surgical Services |
Other Services2 |
Nursery |
Community | TOTAL | |
| Wounds |
20 (7.9) |
141 (55.7) |
53 (20.9) |
11 (4.3) |
28 |
(11.2) | 253 |
| Respiratory tract |
45 (57.0) |
3 (3.8) |
17 (21.5) |
12 (15.2) |
2 |
(2.5) | 79 |
| Urinary tract |
16 (17.2) |
21 (22.6) |
16 (17.2) |
7 (7.5) |
33 |
(35.5) | 93 |
| Ear |
0 |
0 |
0 |
0 |
51 | (100.0) | 51 |
| Blood |
6 (16.2) |
10 (27.0) |
8 (21.6) |
13 (35.2) |
0 | 37 | |
| Eye |
4 (30.8) |
3 (23.0) |
6 (46.2) |
0 |
0 | 13 | |
| CSFa |
0 |
0 |
0 |
8 (100.0) |
0 | 8 | |
| Miscellaneous*3 |
5 (25.0) |
5 (25.J0 |
5 (25.0) |
5 (25.0) |
0 | 20 | |
| TOTAL |
96 |
183 |
105 |
56 |
114 | 554 | |
| 1 Intensive care unit;2 Other services: adult and pediatric medical, obstetric/gynecological; a CSF: cerebrospinal fluid; b Miscellaneous: umbilical swab, stool, peritoneal dialysate fluid; (%)*: percentage. | |||||||
Table 2 shows the frequency of resistance among isolates from hospital and community sources. Community source isolates were fully sensitive to four of the nine antimicrobials tested but showed very low levels of resistance to ciprofloxacin drug and ceftazidime (each 2.6%) and generic gentamicin (7.9%). Imipenem was the only drug to which all hospital and community source isolates were fully sensitive. Although relatively low, hospital isolates showed varying degrees of resistance to the other antimicrobials. canadian antibiotics
Table 2. Prevalence of Resistance to Antimicrobial Agents among Pseudomonas
| Agents among Pseudomonas Aeruginosa Strains isolated from Hospital and Community Sources | |
| Number (%)* of isolates resistant from: | |
| Antimicrobial | Hospital Community N=440 N=114 |
| Piperacillin
Gentamicin Ceftazidime Ciprofloxacin Aztreonam Cefepimea Imipenem |
120 (27.3)* 14 (12.3) 112 (25.5) 9 (7.9) 95(21.6) 0 88 (20.0) 3 (2.6) 52 (11.8) 3 (2.6) 43 (9.8) 10 (8.8) 30 (6.8) 0 11 (2.5) 0 0 0 |
| a Cefepime: Introduced into the country in January 2000; (%)*: percentage.
Except for the major hospitals (SFGH, POSGH, and the EWMSC), the varied sources of each isolate was not always available. However, from among known hospital sources, the most resistant P. aeruginosa isolates were from the respiratory tracts and infected wounds. The drugs to which these strains were most resistant were piperacillin, ceftazidime, and the aminoglycosides, gentamicin, and tobramycin. |
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