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Table 2 Influence of surgical environment characteristics on microbial colony counts assessed by active sampling in working operating rooms

From: Factors influencing microbial colonies in the air of operating rooms

Variables

Number of samples n = 250 (%)

Mean bacterial count (cfu/m3)*

p-value

Indoor air temperature (°C), mean ± SD

 

19.2 ± 0.9

0.101

Indoor air relative humidity (%), mean ± SD

 

59.1 ± 4.4

0.998

Number of indoor staff, n

 

6.2 ± 1.8

0.001

 2 persons

6 (2.4)

43.0 ± 46.3

 

 3 persons

16 (6.4)

57.6 ± 31.4

 

 4 persons

16 (6.4)

78.1 ± 41.1

 

 5 persons

33 (13.2)

75.0 ± 41.2

 

 6 persons

73 (29.2)

73.2 ± 43.7

 

 7 persons

62 (24.8)

76.4 ± 47.1

 

 8 persons

32 (12.8)

101.7 ± 52.9

 

 9 persons

6 (2.4)

109.7 ± 55.5

 

 10 persons and above

6 (2.4)

95–129

 

Frequency of opening the operating room door during a surgical procedure

  

0.231

  < 5

133 (53.2)

73.6 ± 46.8

 

 6–10

76 (30.4)

80.7 ± 45.1

 

  > 10

41 (16.4)

87.1 ± 49.4

 

Sequence of the operation during the day

  

0.690

 First

37 (14.8)

69.4 ± 47.0

 

 Second

56 (22.4)

73.4 ± 43.8

 

 Third

71 (28.4)

84.1 ± 50.9

 

 Fourth

46 (18.4)

83.0 ± 49.1

 

 Fifth

28 (11.2)

73.8 ± 41.6

 

 Sixth and above

12 (4.8)

74–124

 

Surgical stage at air microbial sampling

  

<0.001

 before initial incision

67 (26.8)

99.9 ± 55.7

 

 during incision to wound closure

170 (68.0)

66.9 ± 38.3

 

 after wound closure

13 (5.2)

110 ± 46.6

 

The time of sampling

  

0.608

 8:00–12:00

14 (5.6)

66.6 ± 42.3

 

 12:01–16:00

116 (46.4)

77.6 ± 48.9

 

 16:01–20:00

120 (48.0)

79.7 ± 48.9

 

Total air microbiologic sampling microbial colony counts

 

78.0 ± 46.8

 
  1. *cfu colony-forming units