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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