The types and number of bacteria isolated from infected urine from hospital and general practice patients during the 1996 to 1999 period are shown in tables 1 and 2. The total number of urine specimens processed in hospital practice was 14,853, with an average rate of infection of 6.1% (902/14,853). General practice isolation rate was 27.9% from a total of 5330 specimens. E. coli was the predominant cause of urinary tract infection and its prevalence of isolation was relatively stable during the study period in both hospital and general practice patients. In community practice, isolation rate of Klebsiella pneumoniae was relatively stable during 1996 (19.9%), 1997 (11.6%), and 1998(12.7%), but fell significantly to 1.6% during 1999(p < 0.001).

The rates of isolation of the other members of the Enterobacteriaceae family and Pseudomonas aeruginosa also were relatively stable in the community, except for Citrobacter sppy which increased from 1.3% in 1996 to 20.1% in 1999 (p < 0.001). This rate of Citrobacter isolation also was seen in hospital practice strains where rates increased significantly from 3.4% in 1996 to 24.2% in 1999 (p < 0.001). Enterococci remained relatively constant in isolation in both practices, but were more frequently recovered in 1996 and 1998 in hospital practice. Group В streptococci isolation declined gradually during the study period, but was the most frequently recovered Gram-positive organism from community sources.

table1

The proportion of all organisms isolated from infected urine that were resistant to various antimicrobials in hospital and community practices are shown in Table 3. Nearly 50% of all pathogens from both practices were resistant, and this prevalence of resistance was almost homogenous throughout the 1996 to 1999 study period. Susceptibility to gentamicin, and was better maintained than that of the canadian cephalosporins, and ceftazidime, in both hospital and community practices during the study period. Resistance to tetracycline showed a slow, but gradual decline in hospital practice isolates, but resistance rates of community practice isolates to this drug were relatively stable. There was a gradual improvement in susceptibility of isolates to co-trimoxazole among both hospital and community isolates.

Table 2. FREQUENCY OF ISOLATION OF CAUSATIVE ORGANISMS IN URINARY TRACT INFECTIONS IN COMMUNITY PRACTICE

ORGANISM 1996 1997 1998 1999 Total
N

%

N

%

N

%

N % N %
Gram – negative
Escherichia coli 60 39.7

91

44.2

203 32.2 157

31.5

511 34.4
Klebsiella pneumoniae 30 19.9 24

11.7

80

12.7 8

1.6A

142 9.6
Citrobacter spp. 2

1.3

10

4.9

45

7.1

100

20.1B

157 10.6
Pseudomonas aeruginosa 2

1.3

0

0.0

18

2.9

13

2.6

33 2.2
Enterobacter spp. 3

2.0

5

2.4

35

5.6

63

12.7

106 7.1
Proteus mirabilis 10

6.6

16

7.8

47

7.5

38

7.6

111 7.5
Proteus vulgaris 2

1.3

3

1.5

5

0.8

5

1.0

15 1.0
Acinetobacter spp. 0

0.0

1

0.5

11

1.7

1

0.2

13 0.9
Providencia spp. 1

0.7

1

0.5

0

0.0

3

0.6

5 0.3
Morganella. morganii Others 0

0.0

3

1.5

2

0.3

1

0.2

6 0.4
2

1.3

1

0.5

0

0.0

0

0.0

3 0.2
Total 112

74.2

155

75.2

446

70.8

389

78.1

1102 74.2
Gram – positive
Group В streptococci 15

9.9

21

10.2

24

3.8

19

3.8

79 5.3
Group D streptococci 4

2.6

8

3.9

8

1.3

1

0.2

21 1.4
Enterococci spp 4

2.6

7

3.4

48

7.6

22

4.4

81 5.5
2CoNS 8

5.3

9

4.4

79

12.5

37

7.4

133 9.0
Staphylococcus aureus 5

3.3

4

1.9

19

3.0

19

3.8

47 3.2
Staphylococcus 2

1.3

2

1.0

1

0.2

7

1.4

12 0.8
saprophyticus Others
1

0.7

0

0.0

5

0.8

4

0.8

10 0.7
Total 39

25.8

51

24.8

184

29.2

109

21.9

383 25.8
Overall Total 151 100.0

206

100.0

630

100.0 498

100.0

1485 100.0

Because Escherichia coli was the principal isolate from infected urine, susceptibility of isolates of this species are presented in Table 4. E. coli was more susceptible to co-trimoxazole in hospital practice in 1996 and 1998 than in 1999, while maintaining relative stability in community practice. For E. coli strains from hospital practice, there was a significant increase in prevalence of resistance to cefuroxime (p < 0.001), while among community isolates there was a slight increase but this was not significant. Susceptibility to canadian ampicillin and augmentin drug declined significantly among E. coli strains isolated from both hospital and community practice (p < 0.001). A similar picture was seen acid in both situations. There was no substantial change in susceptibility to gentamicin among urinary E. coli isolates in both practices during the study period, but resistance was increasing among hospital strains. Susceptibility to augmentin showed much improvement among all isolates.

table3

The distribution and frequency of urinary isolates among different groups of patients are shown in Table 5. E. coli was the most frequent isolate among community practice males (30.8%) and females (41.2%), and hospital practice females (38.0%). Members of the Enterobacteriaceae accounted for 70.6% of infections in hospital patients and 72.6% of community patients. Gram-positive bacteria accounted for 18.6% of hospital patients and 21.3% of community patients.

Table 4. PROPORTION OF URINARY ESCHERICHIA COLI RESISTANT TO VARIOUS ANTIBIOTICS

1996

1997

1998

1999

1996

1997

1998

1999

38

61

72

45

Number of E. coli

60

91

203

157

18

29

23

35

% Resistant to all Antimicrobials

18

19

20

22

Significance 1996 vs. 1999 X2    P-value

1996

1997

1998

1999

% E.coli resistant to

1996

1997

1998

1999

Significance 1996 vs. 1999X2      P-value
11.53

< 0.001

53*

54

71

76

Ampicillin

47

56

64

71

11.91

<0.001
15.36

< 0.001

37

48

26

13

Augmentin

40

34

34

12

20.37

<0.001
12.60

< 0.001

42

61

42

67

Tetracycline

38

24

35

43

0.52

NS
27.41

< 0.001

34

57

29

71

2Co – trimoxazole

35

42

34

25

2.38

NS
12.38

< 0.001

5

29

13

22

Nalidixic Acid

5

9

7

26

16.84

<C001
3.91

NS

5

13

14

13

Gentamicin

7

10

8

9

0.27

NS
37.58

< 0.001

3

15

28

38

Cefuroxime

3

8

8

9

3.19

NS

0

5

4

9

Nitrofurantoin

5

6

8

9

1.23

NS

0

0

0

18

Norfloxacin

0

0

0

12

Table 6 shows the distribution of urinary isolates according to age group and sex. Approximately 43% of male patients from both hospital and general practices were below 10 years of age, while 32.7% were females. When combined, UTI isolates were most commonly recovered from the pediatric age group (1-10 years), followed by patients in the 51 years of age and older group.

table5

table6