VARIATIONS IN THE CHARACTERISTICS OF E. COLI INDUCED BY QUATERNARY AMMONIUM COMPOUNDS

1951 ◽  
Vol 14 (4) ◽  
pp. 138-141 ◽  
Author(s):  
C. Kenneth Crocker

Escherichia coli lost the ability to produce gas in liquid media and formed atypical small colony variants on desoxycholate agar, concurrent with induced resistance to quaternary ammonium compounds. Paralleling high resistance, the metallic sheen of colonies on confirmatory medium did not appear. The variant strains showed a decrease in growth rate, failed to reduce methylene blue, and were unable to ferment normal sugars. Thus, with induced resistance, variations occurred in Escherechia coli such as to reduce the value of coliform tests used to identify its presence.

2020 ◽  
Author(s):  
Kari A.C. Green ◽  
Branden S.J. Gregorchuk ◽  
Shelby L. Reimer ◽  
Nicola H. Cartwright ◽  
Daniel R. Beniac ◽  
...  

AbstractQuaternary ammonium compounds (QACs) benzalkonium (BZK) and cetrimide (CET) are common disinfectants used to inhibit or eradicate Gram-negative bacteria in clinical and agricultural products. QAC tolerance in Escherichia coli and other Enterobacterales species can confer cross-resistance to various clinically used antibiotics, making it important to understand mechanisms of QAC tolerance in greater depth. QAC adaptation by E. coli is hypothesized to alter MarRAB regulated genes that converge on the outer membrane, specifically, lipid A biosynthesis and transport genes, porins, and efflux pump systems. To test this, we performed a ‘multi’-omics and phenotypic characterization of E. coli K-12 adapted to BZK and CET, to assess how QACs alter cell growth, genomics, and proteomics. E. coli adapted to either BZK and CET resulted in strains with stable QAC tolerance when either drug was omitted, elongated and narrower cell morphologies by scanning electron microscopy, and reduced growth fitness when compared to un-adapted E. coli. Antimicrobial susceptibility testing revealed that QAC adaptation increased E. coli tolerance by ≥4-fold to BZK, CET, and other QACs but no antibiotic cross-resistance. Single nucleotide variants identified by whole genome sequencing and differentially accumulated proteins by liquid chromatography-mass spectrometry identified alterations to various QAC-adapted E. coli genes and proteins belonging to: lipid A biosynthesis and transport (lpxLM, msbA, mla), the mar-sox-rob regulatory pathway (marR, rob), DNA/protein translation (gyrA, rpsA, rpoB, rapA). These alterations validate the hypothesis that mar-sox-rob network plays a role in QAC tolerance and identifies additional stress inducible genetic and protein QAC tolerant biomarkers.ImportanceBacterial tolerance mechanisms associated with disinfectant QAC adaptation is hypothesized to overlap with the mar-sox-rob multiple antimicrobial resistance pathway but has not been directly shown. Here, we generate QAC tolerant E. coli strains and identify phenotypic changes associated with protein and genetic alterations caused by prolonged QAC exposure. We identified genes that overlap with known antibiotic resistance mechanisms as well as distinct genes and proteins specific to QAC adaptation that are useful for future bacterial disinfectant tolerance mechanism studies. However, these altered genes and proteins implicate MarR and Rob pathways specifically in QAC tolerance but, surprisingly, the involvement of mar-sox-rob pathways did not increase antibiotic cross-resistance. Many altered genes we identified were essential genes in lipid A biosynthesis/transport, DNA and RNA transcription, and protein regulation systems potentially explaining why only QAC cross-tolerance was observed and why we observed greater cell fitness costs despite MarR and Rob pathway involvement.


2020 ◽  
Vol 6 (2) ◽  
pp. 134-142
Author(s):  
Susanne Sütterlin ◽  
Anna Heydecke ◽  
Eva Tano

Background and Aim: Extended-spectrum β-lactamases (ESBL) in Escherichia coli constitutes one of the major threats to modern medicine, and the increasing pollution with quaternary ammonium compounds (QACs) has been suspected to contribute to the spread of ESBL-producing bacteria. The aim of the study was to investigate ESBLA and ESBLM-C-producing E. coli isolates for their coresistance to QACs and their phylogeny isolated from a Swedish University Hospital. Materials and Methods: Coresistance in E. coli with production of ESBL enzymes of the type blaCTX-M (n=23) was compared to E. coli producing AmpC type ESBL enzymes blaCMY and blaDHA (n=27). All isolates were tested for susceptibility to antibiotics and QACs, and high-quality whole-genome sequences were analyzed for resistance determinants. Results: The plasmid-borne small multidrug resistance (SMR) efflux pump sugE(p) was solely present in blaCMY-producing E. coli (n=9), within the same genetic environment blaCMY–blc–sugE(p). Other small multidrug efflux pumps were found without association for ESBL-types: emrE (n=5) and the truncated qacEΔ1 (n=18). Conclusion: Coresistance of ESBL enzymes and SMR efflux pumps in E. coli was common and might indicate that other substances than antibiotics contribute to the spread and emergence of antibiotic resistance.


1953 ◽  
Vol 16 (4) ◽  
pp. 186-188 ◽  
Author(s):  
T. W. Humphreys ◽  
C. K. Johns

Using Escherichia coli as test organism, three quaternary detergent-sanitizers and their constituent QACs were evaluated by modified glass slide and Weber and Black methods at 5°, 20°, and 45°C in artificial hard and distilled waters. QAC activity was reduced by low temperature and water hardness, the latter exerting the greater effect. Each detergent product was more effective than its constituent QAC component alone. Reasons for the earlier endpoints obtained with glass slide method are discussed.


2002 ◽  
Vol 184 (9) ◽  
pp. 2543-2545 ◽  
Author(s):  
Yong Joon Chung ◽  
Milton H. Saier

ABSTRACT SugE of Escherichia coli, first identified as a suppressor of groEL mutations but a member of the small multidrug resistance family, has not previously been shown to confer a drug resistance phenotype. We show that high-level expression of sugE leads to resistance to a subset of toxic quaternary ammonium compounds.


2012 ◽  
Vol 67 (12) ◽  
pp. 2837-2842 ◽  
Author(s):  
S. Buffet-Bataillon ◽  
A. Le Jeune ◽  
S. Le Gall-David ◽  
M. Bonnaure-Mallet ◽  
A. Jolivet-Gougeon

2012 ◽  
Vol 158 (1-2) ◽  
pp. 147-152 ◽  
Author(s):  
C. Soumet ◽  
E. Fourreau ◽  
P. Legrandois ◽  
P. Maris

2007 ◽  
Vol 5 (2) ◽  
pp. 329-333 ◽  
Author(s):  
Cristobal Chaidez ◽  
Javier Lopez ◽  
Nohelia Castro-del Campo

Irrigation water can serve as a vehicle for transporting pathogenic microorganisms, and numerous cases of bacterial infections from consumption of irrigated fresh produce have been reported in recent years. Chlorine-based disinfectants applied when produce is packed are widely used to control microorganisms. When applied properly, the chlorine products are effective. However, hazardous disinfection breakdown products can be formed, and chlorine disinfectants have high oxidant activity that can affect produce quality and pose a risk to food handlers. Quaternary Ammonium Compounds (QACs) are a disinfectant alternative for the washing of fruits and vegetables. They can control a great number of microorganisms, have low toxicity when used at recommended doses, and are stable in storage. The purpose of this work was to assess the disinfectant activity of QACs against Escherichia coli and Staphylococcus aureus under worst-case and average-case turbidity conditions, (2 and 100 nephelometric units); two disinfectant concentrations (100 and 200 mg/L; and two contact times (30 and 120 seconds). Our research showed that QACs were effective against both bacteria. The percentage reduction of Escherichia coli was significantly higher in the less turbid solution (P=0.027), while turbidity did not affect the reduction of Staphylococcus aureus (P>0.05). E. coli was more resistant to QAC treatment than S. aureus. Based on the data obtained we can conclude that QACs could be an alternative in washing processes of fruits and vegetables.


2013 ◽  
Vol 76 (2) ◽  
pp. 200-204 ◽  
Author(s):  
W. N. TAPP ◽  
S. E. GRAGG ◽  
J. C. BROOKS ◽  
M. F. MILLER ◽  
M. M. BRASHEARS

Consumption of food contaminated with Escherichia coli O157:H7 and Salmonella can cause enteric disease in consumers. If not properly sanitized, knives used during animal harvest can spread these and other pathogens. This study evaluated the reduction of E. coli O157:H7 and Salmonella on harvesting knives after nonthermal sanitation. Knives were inoculated in cocktails of E. coli O157:H7 or Salmonella and treated by 30-s immersions in ambient-temperature solutions (unless temperature was specified) of 1.1% sodium metasilicate (SMS), 200 ppm of quaternary ammonium compounds (QAC), 200 ppm of chlorine (Cl2), 5% lactic acid (LA), 82.2°C water, and 21°C water. Initial and treated counts were determined by plating onto MacConkey and xylose lysine desoxycholate for E. coli O157:H7 and Salmonella, respectively. Initial counts were determined by sampling one side of the knife blade, while treated counts were sampled from the opposite side. Plates were incubated for 24 to 48 h at 37°C. Mean attachment of E. coli O157:H7 and Salmonella was 4.51 and 5.09 log CFU/cm2, respectively. Mean log reductions on knives inoculated with E. coli O157:H7 were 1.16, 3.51, 3.38, 1.38, 3.82, and −0.41 CFU/cm2 after treatment in SMS, QAC, Cl2, LA, 82.2°C water, and 21°C water, respectively (P ≤ 0.05). Knives inoculated with Salmonella showed reductions of 0.78, 3.42, 3.40, 2.91, 4.12, and 0.36 log CFU/cm2 after treatment in SMS, QAC, Cl2, LA, 82.2°C water, and 21°C water, respectively (P ≤ 0.05). Results indicate that some ambient-temperature sanitizing agents have the potential to significantly reduce E. coli O157:H7 and Salmonella populations on knives used during animal harvest.


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