Premium
Biofilm parameters influencing biocide efficacy
Author(s) -
Srinivasan Rohini,
Stewart Philip S.,
Griebe Thomas,
Chen ChingI.,
Xu Xiaoming
Publication year - 1995
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260460608
Subject(s) - biofilm , biocide , chemistry , klebsiella pneumoniae , population , pseudomonas aeruginosa , microbiology and biotechnology , bacteria , biology , biochemistry , escherichia coli , sociology , gene , genetics , demography , organic chemistry
The influence of biofilm areal cell density, species composition, and the presence of abiotic particles on the disinfection and removal of bacterial biofilms by monochloramine was investigated. Mono‐ and binary population biofilms of Pseudomonas aeruginosa and Klebsiella pneumoniae were grown on stainless‐steel slides in a continuous flow annular reactor. Biofilms were treated in the reactor with a pulse/step dose of 4 mg/L monochloramine for 2 h. Biofilm samples were disaggregated and assayed for colony formation on R2A agar and for total cell numbers by acridine orange direct counts. These data were used to determine apparent first order rate coefficients for the processes of disinfection and detachment. Disinfection rate coefficients exceeded detachment rate coefficients by as much as an order of magnitude and the two coefficients were poorly correlated ( r = 0.272). The overall decay rate coefficient (disinfection plus detachment) depended strongly on the initial biofilm areal cell density. It displayed a parabolic dependence on cell density with a maximum near 10 8 cfu/cm 2 . This result points to multiple factors influencing biofilm susceptibility to antimicrobial challenge. Decay rates of K. pneumoniae measured in binary population biofilms were comparable with those measured in monopopulation biofilms ( p = 0.61). P. aeruginosa decayed more slowly in biofilsm dominated by K. pneumoniae ( p = 0.028), indicating some interaction between species. The presence of kaolin and calcium carbonate particles in the biofilm reduced disinfection efficacy. © 1995 John Wiley & Sons, Inc.