Coagulase negative staphylococci (CoNS) and Listeria monocytogenes have important roles in pathogenesis of various genital tract infections and fatal foetomaternal infections, respectively. The aim ...of our study was to investigate the inhibitory effects of two novel bacteriocins on biofilms of CoNS and L. monocytogenes genital isolates.
The effects of licheniocin 50.2 from Bacillus licheniformis VPS50.2 and crude extract of bacteriocins produced by Lactococcus lactis subsp. lactis biovar. diacetylactis BGBU1-4 (BGBU1-4 crude extract) were evaluated on biofilm formation and formed biofilms of eight CoNS (four S. epidermidis, two S. hominis, one S. lugdunensis and one S. haemolyticus) and 12 L. monocytogenes genital isolates.
Licheniocin 50.2 and BGBU1-4 crude extract inhibited the growth of both CoNS and L. monocytogenes isolates, with MIC values in the range between 200-400 AU/ml for licheniocin 50.2 and 400-3200 AU/ml for BGBU1-4 crude extract. Subinhibitory concentrations (1/2 × and 1/4 × MIC) of licheniocin 50.2 inhibited biofilm formation by all CoNS isolates (p < 0.05, respectively), while BGBU1-4 crude extract inhibited biofilm formation by all L. monocytogenes isolates (p < 0.01 and p < 0.05, respectively). Both bacteriocins in concentrations of 100 AU/mL and 200 AU/mL reduced the amount of 24 h old CoNS and L. monocytogenes biofilms (p < 0.05, p < 0.01, p < 0.001).
This study suggests that novel bacteriocins have potential to be used for genital application, to prevent biofilm formation and/or to eradicate formed biofilms, and consequently reduce genital and neonatal infections by CoNS and L. monocytogenes.
Multidrug-resistance of methicillin-resistant Staphylococcus aureus (MRSA) is a serious therapeutical problem. Chalcones belong to a group of naturally occurring flavonoids, usually found in various ...plant species, and have potent antibacterial, antiviral and antifungal activities. The goal of this study was to evaluate the antibacterial effect of three newly-synthesized chalcones against clinical isolates of MRSA, and their synergism with β-lactam and non-β-lactam antibiotics.
Antimicrobial activity of the three newly-synthesized chalcones was tested against 19 clinical isolates of MRSA and a laboratory control strain of MRSA (ATCC 43300). The synergism with β-lactams: cefotaxime (CFX), ceftriaxone (CTX), and non-β-lactam antibiotics: ciprofloxacin (CIP), gentamicin (GEN) and trimethoprim/sulphamethoxazole (TMP-SMX) was investigated by checkerboard method.
All evaluated compounds showed significant anti-MRSA activity with MIC values from 25-200 μg/ml. Observed synergism with antibiotics demonstrated that chalcones significantly enhanced the efficacy of CIP, GEN and TMP-SMX.
Our study demonstrated that three newly-synthesized chalcones exhibited significant anti-MRSA effect and synergism with non-β-lactam antibiotics. The most effective compound was 1,3-Bis-(2-hydroxy-phenyl)-propenone. Our results provide useful information for future research of possible application of chalcones in combination with conventional anti-MRSA therapy as promising new antimicrobial agents.
Background
Chronic rhinosinusitis (CRS) is one of the most common health disorders in humans and has a major impact on health-related quality of life (HRQoL). Of the many factors contributing to the ...etiology of CRS, less is known about the correlation between CRS and bacterial biofilms and their impact on HRQoL.
Objective
The aim of this prospective study was to investigate the relationship between biofilm-producing bacteria and patients' objective findings and HRQoL.
Methods
Forty-eight patients with CRSwNP were enrolled in a 12-month prospective study. The Lund-Mackay (LM) CT and endoscopic Lund-Kennedy (LK) scores were obtained before endoscopic sinus surgery (ESS), and patients completed the HRQoL instruments: the 22-item Sinonasal Outcome Test (SNOT−22), the 36-item Short Questionnaire (SF−36), and the visual analog scale (VAS). A sinus culture was obtained at ESS, bacteria were isolated, and in vitro quantification of the biofilm was performed. The LK score and HRQoL were determined postoperatively at months 1, 3, 6, and 12.
Results
The most common bacterial isolates in patients with CRSwNP were Staphylococcus aureus (28%), coagulase-negative staphylococci (52%), and Pseudomonas aeruginosa (8%). Preoperatively, the highest LM and LK scores were found in patients with strong biofilm producers. Postoperative LK scores were significantly reduced in all patients. Postoperative VAS scores were significantly reduced from month 1 to month 12 postoperatively. Patients with strong biofilm producers had significantly worse nasal blockage, secretion, headache, facial pressure and pain, and loss of smell preoperatively, compared to patients with low biofilm producers. The most significant reduction in preoperative scores SNOT−22 and SF−36 (excluding physical functioning) was seen in patients with S. aureus and P. aeruginosa.
Conclusions
Patients with strong biofilm producers had higher LK and LM scores preoperatively, and greater improvement in LK and HRQoL scores postoperatively. Microbiologic surveillance of all CRS patients is recommended.
The types of carbapenemases and clonal relatedness among community isolates of carbapenemase-producing
in Belgrade, Serbia, were determined.
During the period 2016-2020,
community isolates were ...screened for carbapenemases, and carbapenemase production was confirmed by multiplex PCR. Clonality was determined based on genetic profiles obtained by enterobacterial repetitive intergenic consensus PCR.
Carbapenemase genes were detected in 114 of 4800 isolates (2.4%). The most frequent gene was
. Most isolates (70.5%) were grouped in ten clusters. Cluster 11 contained 16.4% of all
-positive isolates, and all
-positive isolates were grouped in one cluster.
Laboratory-based detection and surveillance are highly recommended in order to control the spread of resistance in community settings.
Mastitis is considered to be one of the most important diseases of dairy cows in terms of health, production, and economy. Being the most common cause of antibiotic consumption in dairy cows, ...treatment of this disease is one of the biggest challenges in the veterinary profession as an increasing number of pathogens develop resistance to antibiotics used in the treatment. Therefore, new alternative approaches for limiting the use of antibiotics in livestock are required. For this reason, our study aimed to investigate prevalence of environmental mastitis associated bacterial strains, as well as the sensitivity of isolated strains to different antibiotics. Additionally, the therapeutic potential of three essential oils (EOs) was tested against bovine Serratia spp. and Proteus spp. mastitis pathogens, based on their chemical composition, as well as antibacterial potential. The study was carried out on 81 milk samples collected from dairy cows with mastitis. In order to determine prevalence of S. marcescens and P. mirabilis, microbiological isolation and identification were performed. Antimicrobial susceptibility testing was performed by disk diffusion method and the microdilution method was used to determine the antibacterial activity of selected EOs. In the oregano EO, a total of 23 compounds were detected, with carvacrol as a dominant component (78.94%). A total of 26 components were present in the EO of common thyme, where thymol was the most abundant compound (46.37%). Thymol also dominated (55.11%) the wild thyme EO. All tested EOs displayed antibacterial activity against all strains to different extents, while wild and common thyme EOs were the most effective. It could be concluded that the tested EOs represent promising therapeutic candidates for effective non-antibiotic treatment of mastitis.
Blackthorn (
L.) fruit is bluish-black wild fruit traditionally used in nutrition and medicine. It is recently gaining attention as a functional food and an underutilized source of bioactive ...compounds for application in the food and pharmaceutical industry. This study aimed to assess the health-promoting potential of blackthorn fruits from Serbia by examining their chemical composition and in vitro biological activities. Phytochemical analysis of the blackthorn fruit extracts was performed using LC-DAD-ESI-MS. The total phenolic (TPC), total flavonoid (TFC), total anthocyanin (TAC) content, antioxidant capacity, and enzyme inhibitory activities were determined spectrophotometrically. The antimicrobial and prebiotic properties were tested using the broth microdilution method. Twenty-seven phenolics belonging to the classes of hydroxybenzoic and hydroxycinnamic acids derivatives, flavonoids, and anthocyanins were identified, with caffeoylquinic acid as the most abundant compound. Blackthorn extracts were characterized by notable TPCs, TFCs, and TACs, and free radical scavenging and reducing ability. The enzyme inhibitory effects (IC
= 0.43-2.16 mg/mL) were observed towards
-amylase,
-glucosidase, acetylcholinesterase, and tyrosinase. Blackthorn fruit extracts in a concentration-dependent manner (0.3-5 mg/mL) stimulated the growth of several probiotic microorganisms and their mixtures, especially the yeast
. Obtained results support further evaluation of the functional food potential of blackthorn fruit.
Drug resistance of
is a leading problem in hospital infections. The aim of this study was to determine the best molecular genetic discrimination method for
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
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
isolates, which suggests that other molecular methods are needed to reveal potential relations between genotypic patterns and phenotypic characteristics.
Bovine mastitis, as a significant and prevalent health problem in dairy herds, is primarily attributed to bacterial infections. Yeasts, although considered relatively rare causative agents, have also ...been associated with mastitis in dairy cattle. Current mastitis treatment predominantly relies on antibiotics, with limited emphasis on antifungal treatment. However, mycotic mastitis is challenging to treat, since these fungi are often resistant to antibiotics and may even utilize them for energy. In the current research, the in vivo antimicrobial activity of the essential oil-based formulation (Phyto-Bomat), as a possible alternative mastitis treatment associated with yeasts, was studied. This study involved a total of 68 animals from two dairy farms with diagnosed mastitis, and three treatment groups were established: conventional antibiotic treatment, Phyto-Bomat treatment, and the combination of both. The findings suggest significant variations in the presence of Candida samples based on the treatment administered, and the most significant difference was noted in cows treated with the combination (Phyto-Bomat and antibiotics). Yet, it is important to note that the results reveal that, regardless of the treatment type, there are statistically significant differences in the presence of Candida samples across the examined time points. These results aim to provide valuable insights into the potential of EOs as an alternative therapy in bovine mastitis, specifically targeting yeasts. Such findings could offer new strategies in the mycotic mastitis control and reducing the occurrence of secondary infections following antibiotic treatment.
Bacterial biofilms play an important role in the pathogenesis of chronic upper respiratory tract infections. In addition to conventional antimicrobial therapy, N-acetyl-L-cysteine (NAC) and propolis ...are dietary supplements that are often recommended as supportive therapy for upper respiratory tract infections. However, no data on the beneficial effect of their combination against bacterial biofilms can be found in the scientific literature. Therefore, the aim of our study was to investigate the in vitro effect of N-acetyl-L-cysteine (NAC) and dry propolis extract in fixed combinations (NAC/dry propolis extract fixed combination) on biofilm formation by bacterial species isolated from patients with chronic rhinosinusitis, chronic otitis media, and chronic adenoiditis. The prospective study included 48 adults with chronic rhinosinusitis, 29 adults with chronic otitis media, and 33 children with chronic adenoiditis. Bacteria were isolated from tissue samples obtained intraoperatively and identified using the MALDI-TOF Vitek MS System. The antimicrobial activity, synergism, and antibiofilm effect of NAC/dry propolis extract fixed combination were studied in vitro. A total of 116 different strains were isolated from the tissue samples, with staphylococci being the most frequently isolated in all patients (57.8%). MICs of the NAC/dry propolis extract fixed combination ranged from 1.25/0.125 to 20/2 mg NAC/mg propolis. A synergistic effect (FICI ≤ 0.5) was observed in 51.7% of strains. The majority of isolates from patients with chronic otitis media were moderate biofilm producers and in chronic adenoiditis they were weak biofilm producers, while the same number of isolates in patients with chronic rhinosinusitis were weak and moderate biofilm producers. Subinhibitory concentrations of the NAC/propolis combination ranging from 0.625–0.156 mg/mL to 10–2.5 mg/mL of NAC combined with 0.062–0.016 mg/mL to 1–0.25 mg/mL of propolis inhibited biofilm formation in all bacterial strains. Suprainhibitory concentrations ranging from 2.5–10 mg/mL to 40–160 mg/mL of NAC in combination with 0.25–1 mg/mL to 4–16 mg/mL of propolis completely eradicated the biofilm. In conclusion, the fixed combination of NAC and dry propolis extract has a synergistic effect on all stages of biofilm formation and eradication of the formed biofilm in bacteria isolated from upper respiratory tract infections.
Cultivation of goji berries (GB), fruits of Lycium barbarum L. (Solanaceae), is expanding worldwide, including in Europe. In this study, a comparative analysis of the nutritional value, chemical ...composition and in vitro biological activities of GB from different locations in Serbia was performed. Proximate compositions were evaluated according to standard methods. Minerals were assessed by inductively coupled plasma techniques, while fatty acids, sterols, and phenolic profiles were analyzed by gas- and liquid chromatography-based techniques coupled with flame-ionization, mass spectrometry, or diode array detection. The total content of phenolics, flavonoids, carotenoids, and polysaccharides was assessed using spectrophotometric methods. Methanol extracts from GB were examined for their antioxidant, enzyme inhibitory (α-amylase, α-glucosidase, acetylcholinesterase and tyrosinase) and antibacterial activities. Despite significant variations among samples from different locations, the results confirmed that GB are a valuable source of dietary fiber and protein and are characterized by favorable fatty acid profiles. Phytochemical analysis revealed that β-sitosterol, Δ5-avenasterol, and 24-methyldesmosterol are the predominant sterols and caffeic acid, gallic acid, quercetin and rutin are the main phenols. All GB samples showed both antioxidant and mild antimicrobial activity. A dose-dependent anti-enzymatic activity (IC50 ranging 1.68-6.88 mg/mL) was demonstrated. The results support further promotion of GB cultivation in Serbia and further investigations on their potential applications in various industries.Cultivation of goji berries (GB), fruits of Lycium barbarum L. (Solanaceae), is expanding worldwide, including in Europe. In this study, a comparative analysis of the nutritional value, chemical composition and in vitro biological activities of GB from different locations in Serbia was performed. Proximate compositions were evaluated according to standard methods. Minerals were assessed by inductively coupled plasma techniques, while fatty acids, sterols, and phenolic profiles were analyzed by gas- and liquid chromatography-based techniques coupled with flame-ionization, mass spectrometry, or diode array detection. The total content of phenolics, flavonoids, carotenoids, and polysaccharides was assessed using spectrophotometric methods. Methanol extracts from GB were examined for their antioxidant, enzyme inhibitory (α-amylase, α-glucosidase, acetylcholinesterase and tyrosinase) and antibacterial activities. Despite significant variations among samples from different locations, the results confirmed that GB are a valuable source of dietary fiber and protein and are characterized by favorable fatty acid profiles. Phytochemical analysis revealed that β-sitosterol, Δ5-avenasterol, and 24-methyldesmosterol are the predominant sterols and caffeic acid, gallic acid, quercetin and rutin are the main phenols. All GB samples showed both antioxidant and mild antimicrobial activity. A dose-dependent anti-enzymatic activity (IC50 ranging 1.68-6.88 mg/mL) was demonstrated. The results support further promotion of GB cultivation in Serbia and further investigations on their potential applications in various industries.
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