INFLUENCE OF ORGANIC MATTER ON THE GERMICIDAL EFFICIENCY OF QUATERNARY AMMONIUM AND HYPOCHLORITE COMPOUNDS

1948 ◽  
Vol 26f (2) ◽  
pp. 91-104 ◽  
Author(s):  
C. K. Johns

Using Staphylococcus aureus and Eschericha coli as test organisms, the influence of various concentrations of skim milk on the germicidal potency of Roccal and of Dalglish hypochlorite solutions was studied. Both germicides retained their activity in the presence of unexpectedly high concentrations of skim milk, especially against S. aureus. Small concentrations frequently showed a slight potentiating effect in both laboratory and plant tests. The effectiveness of the hypochlorite fell off sharply beyond a certain concentration, while that of Roccal declined more gradually. Solutions of Roccal prepared with tap water were decidedly less active against E. coli than those prepared with distilled water. With the hypochlorite, tap water solutions were equally effective. Against S. aureus, a similar difference was noted although to a lesser extent. Added skim milk depressed the germicidal action of tap water solutions of Roccal to a greater extent than for distilled water solutions, while for the hypochlorite the reverse held true.

1986 ◽  
Vol 49 (3) ◽  
pp. 233-235 ◽  
Author(s):  
PATRICIA HAGGERTY ◽  
NORMAN N. POTTER

Studies were made to compare the growth and death of Staphylococcus aureus, Streptococcus faecalis and Escherichia coli in skim milk concentrated by ultrafiltration to that in unconcentrated skim milk. Skim milk was volume concentrated to 2× in laboratory-scale stirred UF cells. Behavior of the organisms was analyzed in four inoculated milk samples: 2× retentate, 1× water-diluted retentate, milk equivalent (retentate plus permeate) and unconcentrated skim milk. Growth of each organism and of total aerobes did not vary in the four milk samples at either 7 or 13°C. For S. faecalis and E. coli, D-values for samples heated to 62.7°C did not significantly differ in the four milk samples (p>0.01). The D-value of S. aureus in water-diluted retentate was slightly but significantly lower than those in the other three milk samples (p<0.01), possibly due to the lowered lactose level in this sample.


1952 ◽  
Vol 30 (6) ◽  
pp. 674-681 ◽  
Author(s):  
P. H. H. Gray ◽  
L. J. Taylor

Laurylamine saccharinate has been tested for its bacteriostatic powers against 30 species of bacteria, namely, 6 Gram-positive micrococci, 12 Gram-positive and 12 Gram-negative 'rods'. The compound was used in concentrations of 0.0005, 0.001, and 0.005% in plain broth, broth with glycerol, and broth with glycerol and skim milk, these adjuncts representing progressively increasing amounts of organic matter. The Gram-negative bacteria were the most resistant. The bacteriostatic action of the laurylamine was progressively reduced by the organic matter. Staphylococcus aureus was not killed by 0.005% laurylamine in the medium containing skim milk. Media containing phenol were used as a measure of comparison, and similar effects of organic matter were observed. Agar also reduced the bacteriostatic power of the laurylamine.


2021 ◽  
Author(s):  
Mbarga Manga Joseph Arsene ◽  
Podoprigora Irina Viktorovna ◽  
Anytoulou Kitio Linda Davares ◽  
Mouafo Hippolyte Tene ◽  
Irma Aurelia Monique Manga ◽  
...  

Background and aim: The Cameroonian flora abounds in plants with multidimensional therapeutic virtues which can play an important role in the fight against resistance to antibiotics and the search for new antimicrobials. This study aimed to screen the antimicrobial potential of aqueous and ethanolic extracts of thirteen (13) samples (Bark, leaf, seed) of eight (8) plants from Cameroon against 3 reference pathogens and to evaluate their synergy with conventional antibiotics against eleven (11) multiresistant uropathogenic (MRU) bacteria. Method: Bioactive compounds were extracted from leaves of Leucanthemum vulgare, Cymbopogon citratus (DC.) Stapf, Moringa oleifera Lam and Vernonia amygdalina Delile; barks of Cinchona officinalis and Enantia chlorantha Oliv; barks and seeds of Garcinia lucida Vesque and leaves and seeds of Azadirachta indica (Neem) using distilled water and ethanol as solvents. The extracts were tested against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 6538 and Candida albicans 10231 using the well diffusion method and the microdilution method. The synergistic effect was assessed (using disc diffusion method and the checkerboard method) against MRU bacteria namely Achromobacter xylosoxidans 4892, Citrobacter freundii 426, Enterococcus avium 1669, Escherichia coli 1449, Klebsiella oxytoca 3003, Kocuria rizophilia. 1542, Moraxella catarrhalis 4222, Morganella morganii 1543, Pseudomonas aeruginosa 3057, Staphylococcus aureus 1449 and Streptococcus agalactiae 3984. Results: We found that distilled water extracted a more important mass of phytochemical compounds (7.9-21.2%) compared to ethanol (5.8-12.4%). Except C. officinalis and G. lucida leaves, the rest of extracts were active with inhibition diameters (ID) ranging from 5 to 36 mm. Both ethanolic (EE) and aqueous extract (AE) of E. chloranta bark (ECB) were the most active against all pathogens with the mean ID of 17 and 36 mm vs S. aureus ATCC 6538, 23 and 14 mm vs E. coli ATCC 25922 and 36 and 19 mm vs C. albicans ATCC 10231. Only the EE of E. chloranta bark (ECB) had a strong activity against all the microorganisms tested (MIC <2 mg / ml); L. vulgare leaves (LVL) and G. lucida seed (GLS) had moderate (average MIC of 8 mg/ml) while all other extracts showed very weak antimicrobial activity. In addition, the fractional inhibitory concentration (FIC) ranged from 0.125 to 0.750. No antagonism (FIC> 4) or indifference (1≤ FIC≤4) was noted between the extracts and the antibiotics, but the best synergies were found with ECB which well-modulated Kanamycin (FIC = 0.125 against S. aureus and 0.250 against E. coli), nitrofurantoin (FIC = 0.250 against S. aureus and 0.188 against E. coli) and ampicillin (FIC = 0.125 against E. coli). Similarly, compared to other extracts, ECB, LVL and GLS also well-modulated ampicillin, ceftazidime, tetracycline, nitrofurantoin, and trimethoprim against all the above-mentioned resistant uropathogenic bacteria with important increase in fold area (IFA). Conclusion: This study show that E. chlorantha bark, L. vulgare leaves G. lucida seed, have good antimicrobial activity against both bacteria (Gram positive and Gram negative) and fungi (C. albicans); and should be more investigated for their possible use to the fight against MDR and MRU microorganisms.


2020 ◽  
Vol 6 (2) ◽  
pp. 316-320
Author(s):  
Vajira P Bulugahapitiya ◽  
Rathnaweera TN ◽  
Wijayaratne WMDGB ◽  
Manawadu HC

This study was aimed exploring the cytotoxicity and antimicrobial activity of the leaves D. thwaites is an endemic plant to Sri Lanka. The plant is known for its nutritional and medicinal applications where especially the leaf decoctions are being used to wash skin wounds in indigenous medicine. The brine shrimp lethality assays was performed to evaluate normal toxicity and it gave LC50 value greater than 1000 μg/ mL showing that the plant extracts are non-toxic to the normal cells. The agar-well diffusion assay was performed to assess the antimicrobial activity, and strains of bacteria; E. coli, Staphylococcus aureus, Pseudomonas aeruginosa and Methicillin Resistant Staphylococcus aureus (MRSA) and fungus; Candida albicans were used as test organisms. The results indicated that all the extracts are active against Staphylococcus aureus (Gram Positive) with maximum inhibition shown for methanolic and aqueous extracts. When it was tested against MRSA both aqueous and methanolic extracts gave similar inhibitions. The minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined as 6.25 mg/mL and 100 mg/mL respectively with S. aureus whereas no inhibition observed by any of the extract against Gram negative bacteria and Candida albicans. Thus, this study revealed the leaves of D. thwaites possesses strong anti-bacterial activity against S. aureus and MRSA. The results confirmed the efficacy of using D. thwaites as the natural antimicrobial agent and suggested to develop the leaves into value added products to be used in topical applications as antiseptic solutions or ointments. Asian J. Med. Biol. Res. June 2020, 6(2): 316-320


1977 ◽  
Vol 23 (6) ◽  
pp. 716-720
Author(s):  
A. Chopin ◽  
G. Mocquot ◽  
Y. Le Graet

In this paper a method which allows the measure of microbial death rate during spray-drying by means of a streptomycin-resistant mutant that can be grown on a streptomycin-containing agar is described. Plate counts of Microbacterium lacticum, Escherichia coli, and Staphylococcus aureus recovered from skim milk powders were done on plate count agar in the presence and absence of streptomycin and on various selective media. The powders were produced from evaporated milk previously inoculated with those organisms.Our results showed that the proposed method allows the recovery of 78% of M. lacticum, 61% of E. coli, and 100% of S. aureus that survived spray-drying. Recoveries of surviving E. coli on violet bile agar and brilliant green bile 2% were 34% and 29% respectively. Baird-Parker and mannitol salt agar media allow the recovery of all surviving S. aureus, thus showing that S. aureus cells did not lose their ability to grow in media containing 7.5% NaCl. Our results show that physiological injury of the cells during spray-drying differs from injury due to heating only. [Traduit par le journal]


2020 ◽  
Vol 14 (3) ◽  
pp. 2173-2180
Author(s):  
Ebtehal N. Mahmmoud

One of the most important problems faced by microbiologists is to preserve bacterial isolates in the best state to study and further diagnosis. The current study aims to provide a summary of experimental results to maintain two species of bacteria alive after being stored by using some additives. This study found that the best temperature to preserve Staphylococcus aureus was -20°C for a year, while for Escherichia coli it was the same temperature except in using Glycerol (G) 100% and Food oil (FO) methods. The optimum method to preserve S. aureus was by using Normal Saline (NS), while Distilled Water (DW) was the optimum method to preserve E. coli at temperatures (4, 25 and -20)°C for a year, the phenotypic patterns for examining bacteria were maintained except in NS at 4°C for S. aureus after a year ago. Glycerol was used alone at concentrations (100, 50, 30 and 15)%, and another group used G+NS in the same volumes, good results were achieved when it used alone or with NS to preserve bacteria for six months at 4°C except for methods of G100% and (G100% + NS) for examining bacteria. FO has never been used as preservation liquid, it is successful to survive S. aureus at -20°C for a year, and when it was added to NS, E. coli survived for a year at three temperatures (4, 25 and -20)°C, while S. aureus didn’t survive for a year when FO+NS method used at room temperature. The precipitation method was used for bacterial suspension, then added the preserving liquid, but the results were not effective compared to the First method.


2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Amal Ramzi ◽  
Bouchra Oumokhtar ◽  
Yassine Ez zoubi ◽  
Touria Filali Mouatassem ◽  
Moussa Benboubker ◽  
...  

Background. The microbiological risk of the hospital environment, including inert surfaces, medical devices, and equipment, represents a real problem. Objective. This study is aimed at demonstrating and assessing the antibacterial activity of three synthetic disinfectants classified as quaternary ammoniums on different bacterial strains (Gram-negative and Gram-positive like Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus) isolated from the hospital environment. The reference strains included Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213, and Pseudomonas aeruginosa ATCC 27853 used as negative control strains. Method. Three quaternary ammonium disinfectants were tested: DDN9® (0.5%) which contains didecylmethylpolyoxyethylammonium propionate as an active substance, spray (0.4%) containing quaternary ammonium compounds, and Phagosurf ND® (0.4%) with didecyldimethylammonium chloride. Their effect was evaluated using the disk diffusion technique and the broth dilution methods, allowing the Minimum Inhibitory Concentration (MIC) and then the Minimum Bactericidal Concentration (MBC). Result. Only the growth of Gram-positive bacteria and some strains of Gram-negative bacteria were inhibited by the three synthetic disinfectants. NDD9® demonstrated an antibacterial effect only against the Gram-positive strains (S. aureus and S. aureus ATCC 29213) with a MIC of 0.25 mg/ml. The disinfectant spray showed effect against all four strains including E. coli (9), S. aureus, E. coli ATCC 25922, and P. aeruginosa ATCC 27853 with an inhibitory concentration of 4 mg/ml, while the growth of S. aureus ATCC 29213 was inhibited at 2 mg/ml. The third disinfectant, Phagosurf ND®, inhibited only the growth of S. aureus ATCC 29213 at a MIC of 4 mg/ml. Conclusion. This study is the first here in Morocco to evaluate the bacterial activity of products intended for the control of the healthcare environment. The results obtained on the three disinfectants tested reveal an ineffectiveness against some isolated strains from the hospital environment.


2016 ◽  
Vol 3 (1) ◽  
pp. 25-36
Author(s):  
Shamima Sultana ◽  
A. S. M. Shahidullah ◽  
Md. Mahbubul Islam ◽  
A. F. S. A. Wasey ◽  
Shamsun Nahar

The study was conducted during the period of July 2004 to June 2005 in the   Department of Pharmacology & Therapeutics in collaboration of Department of Microbiology, Mymensingh Medical College, Mymensingh to determine the profile of antibacterial effect of crude neem leaf paste (CNLP), aqueous neem leaf extract (ANLE), and standard antibiotic Ceftriaxone against Staphylococcus aureus, Escherichia coli and, Pseudomonas aeruginosa. Five separate experiments were done e.g. I) Determination of inhibitory effect of crude neem leaf paste (CNLP) by incorporation into nutrient agar media (NA), against Staphylococcus aureus, Escherichia coli and, Pseudomonas aeruginosa. II) Determination of minimum inhibitory concentration (MIC) of aqueous neem leaf extract (ANLE) against that three test organisms by broth dilution technique, III) Determination of minimum inhibitory concentration (MIC) of standard antibiotic ceftriaxcone against test organisms by broth dilution technique as well as making a comparison with MIC of ANLE and IV) Subculture study of materials from effective CNLP, ANLE, NLEE and Ceftriaxone in nutrient agar medium for confirmation of respective results of different experiments conducted. Results revealed that inhibitory effects were observed against the growth of Staph. aureus, Esch. coli and Ps. aeruginosa at 15%, 20% and 25% respectively of CNLP incorporated  into NA media.  The broth dilution technique was followed to determine the MICs of ANLE and Ceftriaxone. The MIC of ANLE was 714 μg/ml against S. aureus and that against E. coli and P. aeruginosa was 1428 μg/ml. The MIC of Ceftriaxone was 10μg/ml against S. aureus and that against E. coli and P. aeruginosa was 25 μg/ml. The MIC of Ceftriaxone was the lowest in comparison to MICs of ANLE. The subculture study showed similar results with that of previous experiments in terms of inhibitory effects of CNLP and MICs of ANLE, Ceftriaxone against all of the organisms studied.  


2020 ◽  
Vol 5 (2) ◽  
pp. 1-5
Author(s):  
Celestina MI

The germicidal efficacy of four common disinfectants used for different purposes was tested against two common pathogens namely Escherichia coli and Staphylococcus aureus . The disinfectants (Dettol, Jik, Izal and Purit) were diluted with sterile distilled water to achieve different concentrations (100%, 50%, 25%, 12.5% and 6.25%) and they were tested on the two organisms using Agar well diffusion method. The plates were allowed to incubate for 24 hours at 37°C.The germicidal efficiency of the disinfectants was evaluated by measuring the zone of inhibition of each disinfectant based on their varying concentrations. Dettol was observed to have the highest inhibition at 100% concentration and was more germicidal on E. coli than S. aureus with Minimal Inhibitory Concentration (MIC) value of 1:16 dilution against the two test organisms. This was closely followed by Jik which also showed more inhibitory activity against E. coli at the initial concentration recording the second highest inhibition rate compared to other disinfectants, but its efficacy decreased as the concentration dropped. Jik exhibited MIC value of 1:8 and 1:2 dilutions for Staphylococcus aureus and Escherichia coli respectively. Purit showed more inhibitory activity on S. aureus with 3.8mm zone of inhibition as against 1.3mm at 100% concentration, recording MIC value of 1:8 dilution on S. aureus and 1:16 dilution for E. coli . The disinfectant Izal was observed to be the lowest as it did not inhibit the growth of any of the organisms, indicating resistance of the organisms to the disinfectant at all concentrations. All the disinfectants apart from Izal inhibited the two test isolates. Only Dettol proved to be best among them. Therefore, Dettol is encouraged to be used in homes to prevent pathogenic infection.


1992 ◽  
Vol 55 (8) ◽  
pp. 627-631 ◽  
Author(s):  
KARL F. ECKNER

Water dispensers with traditional, open reservoirs were tested comparatively against modified, closed reservoirs and modified caps to determine their failure to resist contamination from exterior surfaces of water bottles and aerosols. Bottle rims and caps were surface inoculated with Escherichia coli (SLR 51), Staphylococcus aureus (SLR 717), and Pseudomonas fluorescens (ATCC 13525) at levels approximating 1 × 107 to 1 × 108 cells for a high level and 1 × 103 cells for a low level. The bottles contained 2,000 ml of water. After mounting the bottles on the appropriate water dispenser type, all water was withdrawn from the units 24 h later. Levels of test organisms recovered ranged from 5.0 × 103 to 4.5 × 105 CFU/ml for the high inoculum and 0.39 to 0.84 CFU/ml for the low inoculum in the traditional water dispensing unit. No test organisms (detection limit &lt;0.01 CFU/ml) were recovered from the modified water dispenser for either high or low inoculum level when the unit was sanitized between trials. Test microorganisms were recovered at levels of ≈ 0.06 CFU/ml to ≈0.8 CFU/ml after 3–5 repetitions of very high level (3 × 108 CFU/ml) inoculation with E. coli and S. aureus without sanitization between trials. An aerosol of 2.02 × 109 CFU E. coli per ml was generated in a chamber directly over the water dispensers without bottles mounted for one trial. The modified water dispenser reduced aerosol contamination by 100- to 1,000-fold.


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