scholarly journals Postadaptational Resistance to Benzalkonium Chloride and Subsequent Physicochemical Modifications of Listeria monocytogenes

2002 ◽  
Vol 68 (11) ◽  
pp. 5258-5264 ◽  
Author(s):  
Monica S. To ◽  
Stacy Favrin ◽  
Nadya Romanova ◽  
Mansel W. Griffiths
Keyword(s):  
Fatty Acid ◽  
Listeria Monocytogenes ◽  
Cell Surface ◽  
Benzalkonium Chloride ◽  
Prolonged Exposure ◽  
Efflux Pump ◽  
Adaptation Period ◽  
Cell Surface Antigens ◽  
Physiological Tests ◽  
Sublethal Concentrations

ABSTRACT Many studies have demonstrated that bacteria, including Listeria monocytogenes, are capable of adapting to disinfectants used in industrial settings after prolonged exposure to sublethal concentrations. However, the consequent alterations of the cell surface due to sanitizer adaptation of this pathogen are not fully understood. Two resistant and four sensitive L. monocytogenes strains from different sources were progressively subcultured with increasing sublethal concentrations of a surfactant, benzalkonium chloride (BC). To evaluate the effects of acquired tolerance to BC, parent and adapted strains were compared by using several morphological and physiological tests. Sensitive strains showed at least a fivefold increase in the MIC, while the MIC doubled for resistant strains after the adaptation period. The hydrophobicities of cells of parent and adapted strains were similar. Serological testing indicated that antigen types 1 and 4 were both present on the cell surface of adapted cells. The data suggest that efflux pumps are the major mechanism of adaptation in sensitive strains and are less important in originally resistant isolates. A different, unknown mechanism was responsible for the original tolerance of resistant isolates. In an originally resistant strain, there was a slight shift in the fatty acid profile after adaptation, whereas sensitive strains had similar profiles. Electron micrographs revealed morphological differences after adaptation. The changes in cell surface antigens, efflux pump utilization, and fatty acid profiles suggest that different mechanisms are used by resistant and sensitive strains for adaptation to BC.

scholarly journals Differential Adaptive Response and Survival of Salmonella enterica Serovar Enteritidis Planktonic and Biofilm Cells Exposed to Benzalkonium Chloride

2008 ◽  
Vol 52 (10) ◽  
pp. 3669-3680 ◽  
Author(s):  
Anil K. Mangalappalli-Illathu ◽  
Sinisa Vidović ◽  
Darren R. Korber
Keyword(s):  
Surface Roughness ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Cell Surface ◽  
Acid Composition ◽  
Salmonella Enterica ◽  
Adaptive Response ◽  
Benzalkonium Chloride ◽  
Planktonic Cell ◽  
Planktonic Cells

ABSTRACT This study examined the adaptive response and survival of planktonic and biofilm phenotypes of Salmonella enterica serovar Enteritidis adapted to benzalkonium chloride (BC). Planktonic cells and biofilms were continuously exposed to 1 μg ml−1 of BC for 144 h. The proportion of BC-adapted biofilm cells able to survive a lethal BC treatment (30 μg ml−1) was significantly higher (4.6-fold) than that of BC-adapted planktonic cells. Similarly, there were 18.3-fold more survivors among the BC-adapted biofilm cells than among their nonadapted (i.e., without prior BC exposure) cell counterparts at the lethal BC concentration, and this value was significantly higher than the value for BC-adapted planktonic cells versus nonadapted cells (3.2-fold). A significantly higher (P < 0.05) proportion of surviving cells was noticed among BC-adapted biofilm cells relative to BC-adapted planktonic cells following a 10-min heat shock at 55°C. Fatty acid composition was significantly influenced by phenotype (planktonic cells or biofilm) and BC adaptation. Cell surface roughness of biofilm cells was also significantly greater (P < 0.05) than that of planktonic cells. Key proteins upregulated in BC-adapted planktonic and biofilm cells included CspA, TrxA, Tsf, YjgF, and a probable peroxidase, STY0440. Nine and 17 unique proteins were upregulated in BC-adapted planktonic and biofilm cells, respectively. These results suggest that enhanced biofilm-specific upregulation of 17 unique proteins, along with the increased expression of CspA, TrxA, Tsf, YjgF, and a probable peroxidase, phenotype-specific alterations in cell surface roughness, and a shift in fatty acid composition conferred enhanced survival to the BC-adapted biofilm cell population relative to their BC-adapted planktonic cell counterparts.

scholarly journals Evaluation of the impact of adaptation of Klebsiella pneumoniae clinical isolates to benzalkonium chloride on biofilm formation

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Engy A. Elekhnawy ◽  
Fatma I. Sonbol ◽  
Tarek E. Elbanna ◽  
Ahmed A. Abdelaziz
Keyword(s):  
Klebsiella Pneumoniae ◽  
Cell Surface ◽  
Biofilm Formation ◽  
Benzalkonium Chloride ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Clinical Isolates ◽  
Transcriptional Level ◽  
The Impact ◽  
Sublethal Concentrations

Abstract Background The percentage of the multidrug resistant Klebsiella pneumoniae clinical isolates is increasing worldwide. The excessive exposure of K. pneumoniae isolates to sublethal concentrations of biocides like benzalkonium chloride (BAC) in health care settings and communities could be one of the causes contributing in the global spread of antibiotic resistance. Results We collected 50 K. pneumoniae isolates and these isolates were daily exposed to gradually increasing sublethal concentrations of BAC. The consequence of adaptation to BAC on the cell surface hydrophobicity (CSH) and biofilm formation of K. pneumoniae isolates was explored. Remarkably, 16% of the tested isolates showed an increase in the cell surface hydrophobicity and 26% displayed an enhanced biofilm formation. To evaluate whether the influence of BAC adaptation on the biofilm formation was demonstrated at the transcriptional level, the RT-PCR was employed. Noteworthy, we found that 60% of the tested isolates exhibited an overexpression of the biofilm gene (bssS). After sequencing of this gene in K. pneumoniae isolates before and after BAC adaptation and performing pairwise alignment, 100% identity was detected; a finding that means the absence of mutation after adaptation to BAC. Conclusion This study suggests that the widespread and increased use of biocides like BAC at sublethal concentrations has led to an increase biofilm formation by K. pneumoniae isolates. Enhanced biofilm formation could result in treatment failure of the infections generated by this pathogen.

Efflux pump-mediated benzalkonium chloride resistance in Listeria monocytogenes isolated from retail food

2016 ◽  
Vol 217 ◽  
pp. 141-145 ◽  
Author(s):  
Xiaobing Jiang ◽  
Tao Yu ◽  
Yu Liang ◽  
Shengdong Ji ◽  
Xiaowei Guo ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Benzalkonium Chloride ◽  
Efflux Pump ◽  
Chloride Resistance ◽  
Retail Food

scholarly journals Role of Efflux Pumps in Adaptation and Resistance of Listeria monocytogenes to Benzalkonium Chloride

2006 ◽  
Vol 72 (5) ◽  
pp. 3498-3503 ◽  
Author(s):  
N. A. Romanova ◽  
P. F. G. Wolffs ◽  
L. Y. Brovko ◽  
M. W. Griffiths
Keyword(s):  
Listeria Monocytogenes ◽  
Ethidium Bromide ◽  
Benzalkonium Chloride ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Efflux Pump Inhibitor ◽  
Innate Resistance ◽  
Genes Encoding ◽  
Resistant Strains

ABSTRACT In this study, potential mechanisms underlying resistance and adaptation to benzalkonium chloride (BC) in Listeria monocytogenes were investigated. Two groups of strains were studied. The first group consisted of strains naturally sensitive to BC which could be adapted to BC. The second group consisted of naturally resistant strains. For all adapted isolates, there was a correlation between the resistance to BC and ethidium bromide, but this was not the case for the naturally resistant isolates. To investigate the role of efflux pumps in adaptation or resistance, reserpine, an efflux pump inhibitor, was added to the strains. Addition of reserpine to the sensitive and adapted strains resulted in a decrease in the MIC for BC, whereas no such decrease was observed for the resistant strains, indicating that efflux pumps played no role in the innate resistance of certain strains of L. monocytogenes to this compound. Two efflux pumps (MdrL and Lde) have been described in L. monocytogenes. Studies showed low and intermediate levels of expression of the genes encoding the efflux pumps for two selected resistant strains, H7764 and H7962, respectively. Adaptation to BC of sensitive isolates of L. monocytogenes resulted in significant increases in expression of mdrl (P < 0.05), but no such increase was observed for lde for two adapted strains of L. monocytogenes, LJH 381 (P = 0.91) and C719 (P = 0.11). This indicates that the efflux pump Mdrl is at least partly responsible for the adaptation to BC.

A pre-embedding, protein a-gold immunolabelling technique for cytocentrifuged cell monolayers for lm and tem

1986 ◽  
Vol 44 ◽  
pp. 220-221
Author(s):  
K. Chien ◽  
I.P. Shintaku ◽  
A.F. Sassoon ◽  
R.L. Van de Velde ◽  
R. Heusser
Keyword(s):  
Cell Surface ◽  
Staining Method ◽  
Protein A ◽  
Surface Antigens ◽  
Cell Suspensions ◽  
Cellular Morphology ◽  
Cellular Phenotype ◽  
Cell Surface Antigens ◽  
Cell Monolayers ◽  
Diagnostic Histopathology

Identification of cellular phenotype by cell surface antigens in conjunction with ultrastructural analysis of cellular morphology can be a useful tool in the study of biologic processes as well as in diagnostic histopathology. In this abstract, we describe a simple pre-embedding, protein A-gold staining method which is designed for cell suspensions combining the handling convenience of slide-mounted cell monolayers and the ability to evaluate specimen staining specificity prior to EM embedding.

Quantification of gold labeled cell surface antigens by SEM: Current progress and remaining problems

1990 ◽  
Vol 48 (3) ◽  
pp. 34-35
Author(s):  
Etienne de Harven ◽  
Davide Soligo ◽  
Roy McGroarty ◽  
Hilary Christensen ◽  
Richard Leung ◽  
...  
Keyword(s):  
Cell Surface ◽  
Immunogold Labeling ◽  
Target Antigen ◽  
Facs Analysis ◽  
Becton Dickinson ◽  
Cell Surface Antigens ◽  
Human T Lymphocyte ◽  
Backscattered Electron ◽  
Imaging Mode ◽  
Electron Imaging

Taking advantage of the high elemental contrast of particles of colloidal gold observed in the backscattered electron imaging(BEI) mode of the SEM (1,2), the human T lymphocyte was chosen as a model system to study the potential value of immunogold labeling for the quantification of cell surface expressed molecules. The CD3 antigen which is expressed on all human T lymphocytes and is readily identified by the LEU-4 murine monoclonal antibody (Becton Dickinson, Mountain View, CA) followed by a gold conjugated goat anti-mouse Ig polyclonal antibody was chosen as a model target antigen. When quantified by non-EM methods, using radio-iodinated probes or FACS analysis, approximately 30,000 to 50,000 copies of this antigen per cell are enumerated.The following observations were made while attempting to quantify the same molecule by SEM after specific immunogold labeling:Imaging in the SE vs BE mode: The numbers of gold markers counted in the secondary electron (SE) imaging mode are considerably lower than those counted on the same cells in the backscattered electron (BE) imaging mode.

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