ABSTRACT
Objectives:
to evaluate the microbial load and adherence of Escherichia coli in different areas of the surgical instrument surface exposed to experimental contamination over time.
Methods:
experimental study in which fragments of crile forceps (serrated, rod and rack) were contaminated by immersion in Tryptic Soy Broth, containing 106 CFU/mL of E. coli, for 1, 2, 4, 6, 8, 12 and 24 hours. Microbial load and bacterial adherence were evaluated using microbiological culture and scanning electron microscopy, respectively.
Results:
there was an increase in the microbial load on the surgical instrument, proportional to the contamination interval, ranging from 102 after 1 hour to 105 CFU/cm2 in 24 hours. The presence of exopolysaccharide was detected after two hours of contamination.
Conclusions:
microbial load and adhesion of E. coli increased over time, reaching 105 CFU/cm2 after 24 hours of contamination, starting biofilm formation after two hours.
Descriptors:
Biofilms; Escherichia coli; Surgical Instruments; Patient Safety; Equipment Contamination
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Note: cm - centimeters; h - hours.
Note: HV - acceleration voltage; spot - beam diameter; mag - magnification; WD - working distance; det - detector type; HFW - image width; MC - microscopy center; (A) Jaw (5,000×), (B) Shank (10,000×) and (C) Ratchet (10,000×) after 1 hour, with presence of isolated rods on the surface; (D) Jaw (20,000×) after two hours, with typical E. coli rods grouped in area of slit of the surface of the surgical instrument, with presence of pili and production of amorphous material suggestive of EPS; (E) shank (5,000×) after 2 hours, with isolated rods on the surface of the surgical instrument; (F) ratchet (10,000×) after 2 hours, with rods in the process of cell division agglomerated in slit; (G) jaw (5,000×) after 4 hours - it is observed increase in the concentration of bacteria in relation to the previous time; (H) shank (5,000×) after 4 hours, with clustering of rods in the groove area of the surgical instrument; (I) ratchet (15,000×) after 4 hours, with clustering of rods with evidence of the expression of ribs on the surface of the microbial cell; (J) jaw (5,000×) after 6 hours, with clustering of microorganisms in the central area of the image and presence of isolated cells in the adjacencies; (K) shank (2,000×) after 6 hours - islands with clustering of microorganisms on the surface of the surgical instrument; (L) ratchet (5,000×) after 6 hours, with presence of clustering of rods in the groove area of the surgical instrument; (M) jaw (5,000×) after 8 hours, showing microorganisms dispersed on the surface with EPS production; (N) shank (5,000×) and (O) ratchet (5,000×) after 8 hours, with grouping of microorganisms covered with amorphous material suggestive of EPS; (P) jaw (8,000×), (Q) shank (5,000×) and (R) ratchet (10,000×) after 12 hours – there is a high concentration of E. coli in relation to previous times; (S) jaw (10,000×), (T) shank (5,000×) and (U) ratchet (1,500×) after 24 hours - enlargement of the area filled with microorganisms that agglomerate covering a large part of the surface of the surgical instrument.