Study was conducted on the electrochemical method of preparing colloidal silver at low DC voltage. A natural stabilizer was used as a carob bean gum from the carob bean. Using a UV-Vis ...spectrophotometer and a transmission electron microscope (TEM), colloidal silver (silver nanoparticles) was characterized. It is possible to produce colloidal silver of satisfactory quality by means of this electrochemical method. Silver nanoparticles have exhibited surface plasmon resonance as determined by UV-vis analysis. Based on the TEM analysis, the silver nanoparticles appear to be spherical except in sample E1, where they appear rod-shaped and micrometer-sized. Other three samples had particle sizes ranging from 23-52 nm. In a qualitative analysis of colloidal silver solutions, two types of antibacterial activity were observed. At all dilutions, some colloidal solutions showed better antibacterial activity against gram-positive bacteria (S. aureus, S. pyogenes, E. faecalis) while others displayed better antibacterial activity against gram-negative bacteria (S. enteridis, P. aeruginosa, E. coli).
colonization of water supply pipes is a significant public health problem. The objective of this work was to evaluate
colonization in hotel hot water systems and to investigate the relationship ...between metal concentrations, piping materials (galvanized iron pipes and plastic pipes), and
proliferation. Concentrations of calcium and magnesium ions and the presence of
were determined in a total of 108 water samples from the hot water systems of four hotels in Split-Dalmatia County over a 12-month period, and additional data on piping materials were collected.
was isolated in 23.1% of all samples-in 28.8% (15/52) of water samples from galvanized iron pipes and in 17.8% (10/56) of samples from plastic pipes.
serogroups 2-14 were isolated from all samples. This study found higher prevalence of
at higher concentrations of Ca and Mg ions (except for Mg and plastic pipes). The metal parts of the water supply may be important factors in
contamination due to the possibility of lime scale or roughness of the pipes. Higher Ca and Mg ion concentrations increased the risk of
colonization.
The purpose of this study was to evaluate the prevalence of Legionella spp. and compare the quality of hot water between four facilities for accommodation located in Southern Croatia (the ...Split-Dalmatian County). The research included data collection on the technical and technological characteristics in the period from 2009 to 2012. The survey included a type of construction material for the distribution and internal networks, heating system water heater type, and water consumption. Changes in water quality were monitored by determination of the physical and chemical parameters (temperature, pH, free chlorine residual concentrations, iron, zinc, copper and manganese) in the samples, as well as the presence and concentration of bacteria Legionella spp. The temperature is an important factor for the development of biofilms, and it is in negative correlation with the appearance of Legionella spp. Positive correlations between the Fe and Zn concentrations and Legionella spp. were established, while the inhibitory effect of a higher Cu concentration on the Legionella spp. concentration was proven. Legionella spp. were identified in 38/126 (30.2 %) of the water samples from the heating system with zinc-coated pipes, as well as in 78/299 (26.1 %) of the samples from systems with plastic pipes. A similar number of Legionella spp. positive samples were established regardless of the type of the water heating system (central or independent). The study confirms the necessity of regular microbial contamination monitoring of the drinking water distribution systems (DWDSs).
The use of a suitable method for the enumeration of indicator microorganisms is of crucial importance for reliable monitoring and assessment of the quality of bathing waters. Among other ...characteristics, the method should be selective enough and ensure acceptable relative recovery of target microorganisms. This study presents the basic parameters, relative recovery and categorical performance characteristics of Tryptone Bile X-glucuronide (TBX) agar for
Escherichia coli
(
E. coli
) enumeration in bathing water samples using the membrane filtration method.
The results of the relative recovery study, in which TBX agar was compared against temperature-modified ISO 9308-1:
2014
, showed that in order to achieve a satisfactory relative recovery of
E. coli
with TBX agar at 44 ± 0.5 °C, the resuscitation period on a non-selective medium (Minerals Modified Glutamate Agar, MMGA) at 36 ± 2 °C is crucial. Incubation on a double-layer MMGA/TBX medium with a 6-h resuscitation period and alternating incubation on single-layer MMGA and TBX agar with a 4-h resuscitation period resulted in acceptable and very similar relative recovery. The achieved performance characteristics of the tested medium, double-layer MMGA/TBX agar, are acceptable. The selectivity was matrix-dependent and was 60.6% for inland and 69.9% for coastal waters. No significant effect of the resuscitation period on selectivity was recorded. Finally, the results showed that when the resuscitation period on a non-selective medium is included, TBX agar is a suitable medium for
E. coli
enumeration in bathing water samples using the membrane filtration method and that its use, theoretically, would not have negative effects on the assessment of bathing water quality.
The microbiological colonisation of buildings and man-made structures often occurs on the walls of plumbing systems; therefore, monitoring of opportunistic pathogens such as Legionella pneumophila ...(L. pneumophila), both in water distribution mains and in consumers' plumbing systems, is an important issue according to the international and national guidelines that regulate the quality of drinking water. This paper investigates the presence of L. pneumophila in the Dalmatian County of Croatia and the relationship between L. pneumophila presence and heavy metals concentrations, free residual chlorine and water temperature in hot water distribution systems (WDS). Investigations were performed on a large number of hot water samples taken from taps in kitchens and bathrooms in hotels and homes for the elderly and disabled in the Split region. Of the 127 hot water samples examined, 12 (9.4%) were positive for Legionella spp. with median values concentration of 450 cfu × L(-1). Among positive isolates, 10 (83.3%) were L. pneumophila sg 1, and two of them (16.6%) belonged to the genera L. pneumophila sg 2-14. The positive correlation between the water temperature, iron and manganese concentrations, and L. pneumophila contamination was proved by statistical analysis of the experimental data. On the contrary, zinc and free residual chlorine had no observed influence on the presence of L. pneumophila. The presence of heavy metals in water samples confirms the corrosion of distribution system pipes and fittings, and suggests that metal plumbing components and associated corrosion products are important factors in the survival and growth of L. pneumophila in WDS.
Microorganisms in the air are part of the bioaerosol which is composed of different particles of biological substances, dust particles, bacteria cells and their portions, mould spores and a number of ...by-products of their metabolism. This research focuses on analysing the primary microclimate indicators (temperature and relative humidity) and the presence of microorganisms in the work environment (air). Measurements were taken after the process of sterilisation of infective waste over three months with the objective to determine the total number of aerobic mesophilic bacteria and the total number of moulds. The microclimate indicators were measured with an attested device. The study monitored the microbiological purity of the air in a given place using the sedimentation method, with samples subsequently processed in a microbiology lab in keeping with the prescribed standards. After incubation and following the counting of developed colonies on microbiological substrates (Tryptic soy agar and Sabouraud dextrose agar), different strains of bacteria and moulds were identified. The most common were Gram (+) sporogenes bacteria Micrococcus spp and Staphylococcus spp., and as for fungi the most commonly found were Aspergillus spp and Penicillium spp. It was found that temperature and relative humidity affect the total number of aerobic mesophilic bacteria and fungi which was confirmed using the Wilcoxon equivalent pairs test at the level of statistic significance p<0.05.
SAŽETAK: Mikroorganizmi u zraku sastavni su dijelovi bioaerosola koji se sastoji od različitih čestica biološkog materijala, čestica prašine, bakterijskih stanica i njihovih dijelova, spora gljivica, te dijelova nusprodukata njihovog metabolizma. U ovome istraživanju analizirali su se osnovni pokazatelji mikroklime (temperatura i relativna vlažnost) kao i prisutnost mikroorganizama u radnom okolišu (zraku). Mjerenja su se obavljala poslije procesa sterilizacije infektivnog otpada tijekom tri mjeseca, a određivao se ukupan broj aerobno mezofilnih bakterija i ukupan broj gljiva. Pokazatelji mikroklime određivani su atestiranim uređajem. Ovom studijom pratila se mikrobiološka čistoća zraka, na određenom mjestu metodom sedimentacije, a uzorci su se poslije obrađivali u mikrobiološkom laboratoriju u skladu s propisanim normama. Nakon inkubacije i brojenja izraslih kolonija na mikrobiološkim podlogama (Tryptic soy agar i Sabouraud dextrose agar) identificirani su različiti rodovi bakterija i gljiva. Najčešće su bile zastupljene Gram (+) sporogene bakterije iz roda Micrococcus spp. i Staphylococcus spp., te rodovi gljiva Aspergillus spp. i Penicillium spp. Dokazano je da vrijednosti temperature i relativna vlažnost utječu na ukupan broj aerobno mezofilnih bakterija i gljiva što je potvrđeno Wilcoxonovim testom ekvivalentnih parova na razini statističke značajnosti p<0,05.
In drinking water distribution systems (DWDSs) opportunistic bacteria of environmental origin such as Legionella pneumophila (L. pneumophila) represent a potential source of water contamination, ...resulting in a potential health risk for humans. The main objective of this study includes an integrated approach based on hazard assessment, identification and monitoring of control factors in order to characterize the influence of physical-chemical parameters on L. pneumophila presence in DWDSs as well as to determine possible seasonal effects, with the purpose of improving the prevention measures. The contamination of hot water samples with L. pneumophila was studied in relation to temperature, pH, free residual chlorine, and metal ions concentrations (iron, copper, zinc, manganese, calcium, and magnesium). The results of microbiological and physical-chemical characteristics were analyzed in order to identify the factors that can effectively contribute to reduce legionellae proliferation and risk of human infection. The samples were collected between March 2009 and December 2011 from three hotels and two homes for the elderly and disabled in the Split-Dalmatian County, Croatia. Legionella pneumophila was isolated in 99 out of 304 samples (32.6%). The seasonal L. pneumophila occurrence trends in drinking water distribution systems were observed, with the highest positive samples percentage of 43.5% found within the 3 super(rd) quarter (7-9 month). L. pneumophila contamination was found to be positively associated with Ca, Mg, Fe and Cu concentrations, and negatively associated with Mn concentrations and temperature.
Microorganisms in the air are part of the bioaerosol which is composed of different particles of biological substances, dust particles, bacteria cells and their portions, mould spores and a number of ...by-products of their metabolism. This research focuses on analysing the primary microclimate indicators (temperature and relative humidity) and the presence of microorganisms in the work environment (air). Measurements were taken after the process of sterilisation of infective waste over three months with the objective to determine the total number of aerobic mesophilic bacteria and the total number of moulds. The microclimate indicators were measured with an attested device. The study monitored the microbiological purity of the air in a given place using the sedimentation method, with samples subsequently processed in a microbiology lab in keeping with the prescribed standards. After incubation and following the counting of developed colonies on microbiological substrates (Tryptic soy agar and Sabouraud dextrose agar), different strains of bacteria and moulds were identified. The most common were Gram (+) sporogenes bacteria Micrococcus spp and Staphylococcus spp., and as for fungi the most commonly found were Aspergillus spp and Penicillium spp. It was found that temperature and relative humidity affect the total number of aerobic mesophilic bacteria and fungi which was confirmed using the Wiicoxon equivalent pairs test at the level of statistic significance p<0.05.
The purpose of this study was to compare the quality of hot water between eleven hotels in the Split-Dalmatia County, Croatia that are open year round and 10 summer season hotels and retirement homes ...with irregular use of water. We took 122 samples between May and December 2009. Water temperature and free residual chlorine were measured in situ. Physical and chemical analysis included pH, electrical conductivity, and concentrations of iron, manganese, copper, zinc, calcium, and magnesium that were measured using atomic absorption spectrophotometry, while the Legionella species were determined using a cultivation method on buffered charcoal yeast extract agar. Differences in metal concentrations between the seasonal and year-round accommodation facilities were negligible, save for zinc that was higher in year-round (0.341 mg L(-1)) than in seasonal facilities (0.130 mg L(-1)). Samples from all year-round and six summer season hotels were negative to the Legionella species, but four seasonal facilities turned up with positive samples to Legionella pneumophila. Our study has demonstrated that water quality differs between year-round and seasonal accommodation facilities. These findings suggest that metal plumbing components and associated corrosion products are important factors in the survival and growth of Legionella species in water distribution systems.
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT
• Moclobemide (MCB) undergoes extensive both presystemic and systemic metabolism that can be affected by concomitant drugs.
• Valproic acid (VPA) and ...carbamazepine (CBZ) have been found to interact with psychotropic medications of all classes and many other drugs; VPA acts as a broad‐spectrum inhibitor, and CBZ as a potent inducer of a variety of drug‐metabolizing enzymes.
• There have been no previous studies designed to investigate a potential pharmacokinetic (PK) interaction between MCB and VPA or CBZ; however, these agents are likely to be used concomitantly for the treatment of depressive disorders.
WHAT THIS STUDY ADDS
• VPA does not significantly affect PK or metabolism of MCB at steady state.
• CBZ significantly decreases MCB exposure. This effect is time‐dependent, being more pronounced after 3–5 weeks of co‐administration.
AIM
To assess the impact of valproic acid (VPA) and carbamazepine (CBZ) on moclobemide (MCB) pharmacokinetics (PK) and metabolism at steady state in depressive patients.
METHODS
Twenty‐one inpatients with recurrent endogenous depression received MCB (150 mg t.i.d.), either as monotherapy or in combination with VPA (500 mg b.i.d.) or CBZ (200 mg b.i.d.) in a nonrandomized manner. Steady‐state plasma PK parameters of MCB and its two metabolites, Ro 12‐8095 and Ro 12‐5637, were derived. Clinical assessments of treatment efficacy were performed weekly using standard depression rating scales.
RESULTS
CBZ, but not VPA, was associated with decreases in the MCB AUC by 35% from 7.794 to 5.038 mg h l−1; 95% confidence interval (CI) −4.84863, −0.66194; P = 0.01 and Cmax by 28% (from 1.911 to 1.383 mg l−1; 95% CI −0.98197, −0.07518; P < 0.05), and an increase in its oral clearance by 41% (from 0.323 to 0.454 l h−1 kg−1; 95% CI 0.00086, 0.26171; P < 0.05) after 4 weeks of co‐administration. MCB through concentrations were also decreased, on average by 41% (from 0.950 to 0.559 mg l−1; 95% CI −0.77479, −0.03301; P < 0.05). However, the efficacy in this group of patients was not inferior to the controls, for several possible reasons. Overall tolerability of all study medications was good.
CONCLUSIONS
VPA does not significantly affect PK or metabolism of MCB, whereas CBZ time‐dependently decreases MCB exposure, probably by inducing metabolism of MCB and its major plasma metabolite. The actual clinical relevance of the observed MCB–CBZ PK interaction needs to be further evaluated in a more comprehensive study.
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