Phenotypic and genetic properties of susceptible and multidrug-resistant Pseudomonas aeruginosa isolates in Southern Serbia.

Drug resistance of Pseudomonas aeruginosa is a leading problem in hospital infections. The aim of this study was to determine the best molecular genetic discrimination method for Pseudomonas spp. isolates among 94 outpatients and inpatients and see their grouping by phenotype characteristics (biofilm formation, frequency of serotypes, pigmentation, production of different class of beta-lactamases, and susceptibility to different antibiotic classes) and genotype. The most common serotypes were P1, P6, and P11, while co-productions of pyoverdine and pyocyanin were observed in 70 % of isolates. A total of 77.66 % isolates were mostly weak and moderate biofilm producers. Isolates were susceptible to colistin (100 %), aztreonam (97.87 %), imipenem (91.49 %), doripenem (90.43 %), and meropenem (84.04 %). MICs values confirmed susceptibility to ceftazidime and cefepime and singled out meripenem as the most effective inhibitor. Most isolates were resistant to aminoglycosides and fluoroquinolones. Only two isolates produced ESBL, eight were carbapenemase producers, and five isolates produced MBLs. Twenty-nine isolates were multidrug-resistant; 82.8 % of which produced both pigments, 58.3 % were non-typeable, while the P6 and P11 serotypes were equally distributed (16.7 %). Thirteen MDR isolates were strong enzyme producers. RAPD PCR analysis using primer 272 proved the best at discriminatory fingerprinting for Pseudomonas isolates, as it allocated 12 clusters. A correlation between DNA patterns and antibiotic resistance, production of pigments, serotypes distribution, and biofilm formation was not observed, and only confirmed higher genetic heterogeneity among P. aeruginosa isolates, which suggests that other molecular methods are needed to reveal potential relations between genotypic patterns and phenotypic characteristics.

Physicochemical properties and mineral content of honey samples from Vojvodina (Republic of Serbia).

Forty-five honey samples of three honey types - two monofloral (acacia and sunflower) and one polyfloral (meadow) were collected from the Autonomous Province of Vojvodina (Republic of Serbia) and analysed for their physicochemical parameters (moisture, acidity, pH, ash, electrical conductivity, glucose, fructose, hydroxymethylfurfural (HMF), CIE L∗a∗b∗ colour and mineral content). All tested physicochemical parameters were in agreement with the EU regulation except for moisture (4 samples) and HMF content (1 sample). Principal component analysis (PCA) was used for assessing the effects of three honey types on all investigated physicochemical parameters. According to PCA, acacia honey samples can be clearly isolated and form a cluster, while, regarding other honey types, PCA can offer the possibility to distinguish sunflower and meadow honey samples regarding examined physicochemical parameters and mineral content.

Aflatoxins contamination of maize in Serbia: the impact of weather conditions in 2015.

In recent years climate changes recorded in temperate regions of Europe have led to aflatoxin (AF) contamination of maize. Thus, the aim of this study was to investigate the influence of weather conditions on levels of aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1) and aflatoxin G2 (AFG2) in 180 maize samples collected from the main maize-growing regions (Western Backa, North Banat, South Banat and Central Serbia) in Serbia after harvest in 2015. The concentrations of AFs were determined by a validated HPLC method with post-column derivatisation and fluorescence detection (HPLC-FLD). The presence of AFB1, AFB2, AFG1 and AFG2 was detected in 57.2%, 13.9%, 5.6% and 2.8% of maize samples in the concentration ranges of 1.3-88.8 µg kg-1, 0.60-2.8 µg kg-1, 1.8-28.5 µg kg-1 and 2.1-7.5 µg kg-1 respectively. The recorded smaller amount of precipitation and especially higher air temperatures during the summer of 2015 were favourable for AF production, which resulted in 32.2% and 21.1% of samples being unsuitable for human consumption, since AFB1 and the sum of AFs concentrations were above 5.0 and 10.0 µg kg-1 respectively. Furthermore, the findings in this study indicate that the microclimate conditions in the investigated regions had a great influence on the contamination frequency of maize with AFs. The highest percentage of samples unsuitable for human consumption, considering both AFB1 and total AFs content were 72.5% and 51.5% respectively from Central Serbia, whilst the lowest percentages of 15.6% and 6.2% respectively were found in Western Backa. These findings confirmed that maize should be continuously monitored in order to protect human and animal health from the harmful effects caused by AFs contamination.

Valorisation of raspberry and blueberry pomace through the formulation of value-added gluten-free cookies.

Successful valorisation of raspberry and blueberry pomace was achieved through their application, as dried and ground powders, in the formulation of value-added gluten-free cookies. Simplex-lattice mixture design approach was applied to obtain the product with the best sensory properties, nutritional profile and antioxidant activity. The highest desirability of 90.0 % was accomplished with the substitution of gluten-free flour mixture with 28.2 % of blueberry and 1.8 % of raspberry pomace. The model was verified. Optimized cookies had similar protein (3.72 %) and carbohydrate (66.7 %) contents as gluten-containing counterparts used for comparison, but significantly lower fat content (10.97 %). Daily portion of the optimized cookies meets: 5.00 % and 7.73 % of dietary reference intakes (DRIs) for linoleic acid, 23.6 % and 34.3 % of DRIs for α-linolenic acid and 10.3 % and 15.6 % of DRIs for dietary fibers, for male and female adults, respectively. The nutritional profile of the optimized formulation makes it comparable with added-value gluten-containing counterparts.

Antioxidant Capacity, Mineral Content and Sensory Properties of Gluten-Free Rice and Buckwheat Cookies.

Light buckwheat flour was used to substitute rice flour at the level of 10, 20 and 30% to produce gluten-free cookies. The substitution of gluten-free cookie formulation with light buckwheat flour contributed to the significantly higher mineral content, especially magnesium, potassium, iron and copper, in comparison with the control rice cookies (p<0.05). Gluten-free cookies made with rice flour and buckwheat flour exhibited significantly higher total phenolic and rutin content, scavenging activity against 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH•), antioxidant activity and reducing power than the control cookies (p<0.05). Comparing all evaluated sensory properties, cookies containing 20% of light buckwheat flour had the most acceptable sensory properties. The obtained results of principal component analysis showed that the cookies with 20 and 30% buckwheat flour had better antioxidant and sensory properties in comparison with other two cookie samples.

Pseudomonas aeruginosa serotypes and resistance to antibiotics from wound swabs.

INTRODUCTION/AIM: Pseudomonas aeruginosa (P. aeruginosa) is the most common cause of wound infections, following the disruption of the skin or mucous membranes integrity. The aim of this study was to analyze of the presence P. aeruginosa in wound swabs, antibiotics susceptibility testing, determination of the minimum inhibitory concentrations (MICs) of antibiotics, testing of the metallo-ß-lactamases (MBLs) production, isolates serotyping and analysis of the most common serotypes resistance. METHODS: A total of 90 outpatients and 55 intpatients wound swabs were cultivated. Wound swabs were taken from the patients with wound infections symptoms. Antibiotics susceptibility testing was performed to: meropenem, imipenem, piperacillin-tazobactam, ceftazidime, cefepime, amikacin, gentamicin, netilmicin, of loxacin, ciprofloxacin and colistin (HiMedia). Polyvalent and monovalent antisera for agglutination (Biorad) were used in P. aeruginosa agglutination. RESULTS: P. aeruginosa was isolated from 36.55% wound swabs (36.66% of the inpatients wounds and 36.36% of the outpatients). The analyzed isolates showed the highest degree of sensitivity to colistin (100%) and meropenem (93.44%) and the lowest to cefepime (19.54%). The majority of the inpatients isolates had 12 µg/mL (28.57%) MIC for piperacillin-tazobactam and 16 µg/ml (28.57%) for the outpatients. The most common MICs for ciprofloxacin were 0.19 µg/mL (31.81%) for the nosocomial isolates, and 0.25 µg/mL (28.57%) for the outpatients' ones. The most common ICs for amikacin of the nosocomial isolates were 6 µg/ml (40.90%), and for the outpatients ones 4 µg/mL (33.33%). Five (9.43%) isolates produced MBLs. The most common serotypes were P11 (22.64%), P6 (15.09%) and P1 (11.32%). CONCLUSION: Neither the increased presence of P. aeruginosa was noticed in wounds swabs, nor the antibiotic resistance in the nosocomial isolates compared to those from outpatients. The analyzed isolates had the higest sensitivity to colistin and meropenem, and the lowest to cefepime.

Synergistic effect of Myrtus communis L. essential oils and conventional antibiotics against multi-drug resistant Acinetobacter baumannii wound isolates.

Acinetobacter baumannii is a rapidly emerging, highly resistant clinical pathogen with increasing prevalence. In recent years, the limited number of antimicrobial agents available for treatment of infections with multi-drug resistant (MDR) strains reinforced tendency for discovery of novel antimicrobial agents or treatment strategies. The aim of the study was to determine antimicrobial effectiveness of three Myrtus communis L. essential oils, both alone and in combination with conventional antibiotics, against MDR A. baumannii wound isolates. The results obtained highlighted the occurrence of good antibacterial effect of myrtle oils when administered alone. Using checkerboard method, the combinations of subinhibitory concentrations of myrtle essential oils and conventional antibiotics, i.e. polymixin B and ciprofloxacine were examined. The results proved synergism among M. communis L. essential oils and both antibiotics against MDR A. baumannii wound isolates, with a FIC index under or equal 0.50. Combination of subinhibitory concentrations of essential oils and ciprofloxacin most frequently reduced bacterial growth in synergistic manner. The similar has been shown for combination with polymyxin B; furthermore, the myrtle essential oil resulted in re-sensitization of the MDR wound isolates, i.e. MICs used in combination were below the cut off for the sensitivity to the antibiotic. Time-kill curve method confirmed efficacy of myrtle essential oil and polymyxin B combination, with complete reduction of bacterial count after 6h. The detected synergy offers an opportunity for future development of treatment strategies for potentially lethal wound infections caused by MDR A. baumannii.

[Serotyping and analysis of produced pigments kinds by Pseudomonas aeruginosa clinical isolates].

BACKGROUND/AIM: Pseudomonas aeruginosa (P. aeruginosa) is divided into 20 serotypes on the base of the International Antigenic Typing Scheme. P. aeruginosa serotyping is important because of few reasons but epidemiological is the most important. The aim of the study was serotyping of P. aeruginosa clinical isolates, analysing of single clinical isolates P. aeruginosa present in the particular samples, and analysing of pyocianin and fluorescin production in different isolates of P. aeruginosa. METHODS: A total of 223 isolates of P. aeruginosa, isolated in the microbiological laboratory of the Health Center "Aleksinac", Aleksinac, were examinated. P. aeruginosa isolates were put on the pseudomonas isolation agar, pseudomonas agar base, acetamid agar, asparagin prolin broth, pseudomonas asparagin broth, Bushnnell-Haas agar, cetrimid agar base, King A and King B plates, plates for pyocianin production, plates for fluorescin production and tripticasa soya agar (Himedia). Polyvalent and monovalent serums were used in the agglutination (Biorad). Pigment production was analysed on the bases of growth on the plates for pyocianin and fluorescin production. RESULTS: Serologically, we identificated the serovars as follows: O1, O3, O4, O5, O6, O7, O8, O10, O11 and O12. O1 (38%) was the most often serovar, then O11 (19%) and O6 (8.6%). A total of 18.6% (42) isolates did not agglutinate with any serum, whereas 21 isolates agglutinated only with polyvalent serum. The majority of P. aeruginosa isolates produced fluorescin, 129 (58.54%), 53 (22.94%) produced pyocianin whereas 49 (21.21%) isolates produced both pigments. CONCLUSION: P. aeruginosa was isolated most of the from urine, sputum and other materials. The majority often serovars were O1, O6 and O11. The most of isolates produced fluorescin (58.54%), while 22.94% producted pyocianin and 21.21% both pigments.