Inhibitory Effect of Copper and Zinc Ions on the Growth of Streptococcus pyogenes and Escherichia coli Biofilms.

Analysis of the effect of copper and zinc ions on Streptococcus pyogenes and Escherichia coli biofilms revealed significant differences in the effect of these metals in the form of sulfates or chlorides on biofilm formation. Zinc ions in low doses (salt concentration 0.005 M) inhibited the growth of S. pyogenes biofilms by 1.5 times. After increasing salt concentration to 0.05-0.5 M, the growth of biofilm was reduced by 2.5 times in comparison with the positive control. In case of E. coli biofilms, the inhibition was more pronounced: zinc sulfate in a concentration of 0.005 M reduced its growth by 4.6 times in comparison with the positive control. After increasing salt concentration, the growth of E. coli biofilm decreased by 6.8 times. In case of zinc chloride, zinc ions produced weaker effect and reduced biofilm growth by 2.2 and 5 times, respectively. Copper salts in a concentration of 0.005 M had practically no effect on the growth of S. pyogenes biofilm; with increasing salt concentration, the degree of inhibition was close to the effect of zinc. In case of E. coli biofilm, we observed a slight inhibition of the growth by low doses of copper ions (by 1.4-1.3 times); with increasing salt concentration the effect increased by 5.6 and 2.2 times for copper sulfate and chloride, respectively. Copper and zinc cations had no effect on mature biofilm.

[Deceleration of bacterial growth in Staphylococcus aureus and Pseudomonas Aeruginosa cultures in the presence of copper and zinc cations].

AIM: Evaluate antibacterial effects of millimole concentrations of copper and zinc cations used as sulfates or chlorides in S. aureus and P. aeruginosa cultures. MATERIALS AND METHODS: Suspension of S. aureus or P. aeruginosa containing 108 CFU/ml were lawn-seeded onto Petri dishes with nutrient agar. 30 minutes later salt solution of copper or zinc with concentrations by metal cation from 10(-9) or 10(-6) M to 5 x 10(-1) M were applied to the surface of the lawn by 5 µ drops using a 36-channel stamp-replicator. Dishes with bacterial cultures were then incubated for 16-18 hours at 37°C, and diameter of growth inhibition zone was measured afterwards. For evaluation of the presence (absence) ofviable bacteria in growth inhibition zones, seeding of the material from the center of the zone was carried out into tubes with nutrient broth that were thermostated up to 5 days at 37°C, clarity of the nutrient broth was then evaluated. RESULTS: Inhibiting effects of zinc sulfate against S. aureus surpass effects of copper sulfate by 1.3-1.6 times (p < 0.001-0.05) within metal concentrations from 50 to 500 MM. The effects of zinc chloride in S. aureus culture surpass effects of copper chloride by 1.2-1.6 times (p < 0.02) for cation concentrations of 100 and 500 mM. In P. aeruginosa cultures, antibacterial effects of copper sulfate are comparable with effects of zinc sulfate. The effects of copper chloride on P. aeruginosa cells are 1.2 times more pronounced (p < 0.05) than effects of zinc chloride for metal concentration of 500 mM. Material seeding from zones of culture growth suppression detects turbidity of nutrient broth in samples with specimens from wells treated with zinc salts and broth clarity in samples from wells treated with copper salts. CONCLUSION: In millimole con- centrations, copper and zinc cations have pronounced antibacterial effects in cultures of S. aureus and P. aeruginosa. It is realized as bactericidal in the presence of copper cations and bacteriostatic - in the presence of zinc cations. S. aureus bacteria turn out to be more sensitive to the effects of zinc cations, evaluated by zones of growth inhibition, than P. aeruginosa. The latter show a higher, than S. aureus, tolerance to copper and zinc. Wherein, P. aeruginosa toler- ance to copper cations is surmountable.

[Effects of copper and zinc cations bound by gamma-globulin fraction in Staphylococcus aureus culture].

UNLABELLED: AIM. Evaluation of Staphylococcus aureus culture growth dynamics in the presence of gamma-globulin: metal-complexes formed with copper and zinc cations as well as cations of metals used in isolation during the first 24 hours of exposition. MATERIALS AND METHOD: . Samples of human gamma-globulin metal-complexes with copper or zinc cations at a final concentration of 0.5 microg/ml were introduced into S. aureus bacteria suspensions containing approximately 10(3) CFU/ml. Suspension at the volume of 5.0 ml was incubated at 37 degrees C for 24 hours with sampling and CFU calculation in the culture at various exposure periods. An accepted micromethod for determination of viability of bacteria was used. RESULTS: The protein transformed by copper cation binding realizes bacteriostatic activity in the logarithmic growth phase of S. aureus culture from 3.0 to 6.0 hours of incubation. Free copper cations inhibit bacterial reproduction at a higher degree than the metal-complex. The protein transformed by zinc cation binding realizes bacteriostatic activity at 1.5 hours of S. aureus incubation. Free zinc cations do not have bacteriostatic effect against S. aureus. CONCLUSION: Proteins of the gamma-globulin fraction in the range of physiological concentrations forming metal-complexes with copper and zinc cations may be factors that have cytostatic effect against S. aureus bacteria. Zinc cations realize bacteriostatic activity only in gamma-gloulin bound state whereas copper cations--also in the free state.

[A comprehensive evaluation of the biological properties of the causative agents of typhoid fever isolated from patients and carriers]. / Kompleksnaia otsenka biologicheskikh svoistv vozbuditelei briushnogo tifa, vydelennykh ot bol'nykh i nositelei.

The biological properties of 106 S. typhi cultures were studied; of these, 59 cultures were isolated from 45 chronic carriers and 47 cultures, from 23 typhoid fever patients. According to the degree of their virulence (CPD50 in the continuous cell-line culture Hep-2), the strains isolated from the patients were more virulent than those isolated from the chronic carriers. The mean value of lg CPD50 was 5.76 +/- 0.04 for the patients and 6.86 +/- 0.03 for the chronic carriers. The strains isolated from the patients showed greater variability in the degree of their virulence. The study of the plasmid spectrum showed that 9.4 +/- 5.6% of the strains contained plasmids. From the patients plasmid-containing strains were isolated more frequently than from the carriers (14.9 +/- 2.5% and 5.1 +/- 2.9%). Multiresistance to antibiotics in combination with the presence of plasmids was detected in 6 strains isolated from the typhoid patients with morbidity having the character of outbreaks.

[A comparative analysis of the Salmonella typhi strains isolated from patients and bacterial carriers]. / Sravnitel'nyi analiz shtammov Salmonella typhi, vydelennykh ot bol'nykh i bakterionositelei.

The comparative analysis of 133 S. typhi clinical strains isolated from patients and carriers in Dnepropetrovsk Province in 1978-1987 was carried out. As shown by this analysis, 10 Vi phage types were represented in the set of strains under study, phage types A and F1 being the most numerous ones. Phage type F1 occurred less frequently among the strains isolated from carriers. 31.1% of the strains were found to contain plasmids with different molecular weight ranging from 96 to 0.5 MD. The occurrence of plasmid-containing strains remained at the same level during the whole period under study. Low-molecular plasmids occurred more frequently in the strains isolated from carriers. The minimal suppressive concentrations of a number of antibiotics, such as penicillin, ampicillin, monomycin, chloramphenicol, tetracycline, rifampicin and streptomycin, were determined. 7% of the strains were resistant to penicillin, 9% to monomycin, 15%--to tetracycline and 2.6% to chloramphenicol. The correlation between penicillin and monomycin resistance of the strains and the presence of the plasmid with a molecular weight of 60 MD in these strains was established. All strains were shown to be highly variable in the degree of their virulence: from 10(2) to 10(8). The strains isolated from patients possessed greater virulence.

[The variability of a Pseudomonas aeruginosa population in the phase of parasitism on Tetrahymena pyriformis]. / Izmenchivost' populiatsii Pseudomonas aeruginosa v fazu parazitizma na Tetrahymena pyriformis.

Types of interaction between P. aeruginosa and T. pyriformis have been studied. The study has revealed that phagocytizing protozoa are killed by P. aeruginosa in the process of their joint cultivation. The data obtained in this study indicate that in the process of interaction of these species phagocytosis-resistant cells are selected from heterogeneous microbial population. The use of this model is believed to be promising in the study of the fate of P. aeruginosa in abiotic and biotic environment.