aDepartment of Microbiology, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran
bLaboratory Science Research Center, Golestan University of Medical Sciences, Gorgan, Iran
cSchool of Health, Golestan University of Medical Sciences, Gorgan, Iran
Copyright ©2018, Korea Centers for Disease Control and Prevention
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Mean OD value | Biofilm formation |
---|---|
OD ≤ ODc * | None |
ODc < OD ≤ 2× ODc | Weak |
2× ODc < OD ≤ 4× ODc | Moderate† |
4× ODc < OD | Strong† |
Mean OD value | Biofilm formation |
---|---|
OD ≤ ODc |
None |
ODc < OD ≤ 2× ODc | Weak |
2× ODc < OD ≤ 4× ODc | Moderate |
4× ODc < OD | Strong |
Characteristics (No.) | No. (%) of biofilm formation | No. (%) of gene present | |||
---|---|---|---|---|---|
MTP | TM | CRA | icaA | icaD | |
Clinical specimen | |||||
| |||||
Blood (25) | 15 (60) | 15 (60) | 6 (24) | 25 (100) | 23 (92) |
Tracheal aspirate (6) | 3 (50) | 4 (67) | 1 (17) | 6 (100) | 6 (100) |
Eye exudate (6) | 3 (50) | 3 (50) | 2 (33) | 6 (100) | 6 (100) |
Urine (4) | 1 (25) | 0 | 1 (25) | 4 (100) | 4 (100) |
p | 0.5 | 0.15 | 0.12 | 0.36 | |
| |||||
Hospital ward | |||||
| |||||
ICU (13) | 11 (84.6) | 6 (46.1) | 3 (23) | 13 (100) | 12 (92.3) |
Pediatric (10) | 4 (40) | 5 (50) | 3 (30) | 10 (100) | 10 (100) |
Internal medicine (7) | 3 (42.8) | 5 (71.4) | 1 (14.2) | 7 (100) | 6 (86) |
Neurology (5) | 2 (40) | 3 (60) | 2 (40) | 5 (100) | 5 (100) |
Infectious diseases (4) | 2 (50) | 2 (50) | 0 | 4 (100) | 4 (100) |
Women’s surgical (2) | 0 | 1(50) | 1 (50) | 2 (100) | 2 (100) |
p | 0.04 | 0.075 | 0.074 | 0.11 | |
| |||||
Patient age (y) | |||||
| |||||
< 20 (19) | 11 (57.9) | 9 (47.3) | 6 (31.6) | 19 (100) | 18 (95) |
20 – 45 (7) | 4 (57.1) | 6 (85.7) | 1 (14.2) | 7 (100) | 7 (100) |
> 45 (15) | 7 (46.7) | 7 (46.7) | 3 (20) | 15 (100) | 14 (93) |
p | 0.915 | 0.218 | 0.703 | 0.373 | |
| |||||
Patient gender | |||||
| |||||
Female (25) | 13 (52) | 12 (48) | 9 (36) | 25 (100) | 24 (96) |
Male (16) | 9 (56.2) | 10 (62.5) | 1 (6.2) | 16 (100) | 15 (94) |
p | 0.79 | 0.36 | 0.06 | 0.48 | |
| |||||
Total (41) | 22 (53.6) | 22 (53.6) | 10 (24.4) | 41 (100) | 39 (95.1) |
Method | % of statistical parameter | |||||
---|---|---|---|---|---|---|
SN | SP | PPV | NPV | PLR | NLR | |
TM | 64 | 58 | 64 | 58 | 1.52 | 0.62 |
CRA | 18 | 68 | 40 | 42 | 0.56 | 1.2 |
PCR | 45.5 | 68 | 62.5 | 52 | 1.42 | 0.8 |
Mean OD of negative control + 3× SD of negative control. Isolates with strong or moderate biofilm were considered biofilm producers. OD = optical density; ODc = optical density cut off.
CRA = congo red agar; MTP = microtiter plate; TM = tube method.
CRA = congo red agar; NLR = negative likelihood ratio; NPV = negative predictive value; PCR = polymerase chain reaction; PLR = positive likelihood ratio; PPV = positive predictive value; SN = sensitivity; SP = specificity; TM = tube method.