Gabinaitienė, Aušra

Meat is one of the most popular food sources in the human diet in today´s age. The produce is a constant subject to contamination with microorganisms from farm to fork. A common pathogen for the contamination of minced meat is Escherichia coli. Studies have shown a possible prevalence of E. coli from retail ground beef of up to 55%. Furthermore, E. coli has been proven to be resistant to certain antimicrobial agents. This is posing a significant challenge to the food safety, quality and the public health. To prevent and identify contamination, food quality and safety indicators including aerobic colony count and E. coli number can be used. In total, 20 minced meat samples have been collected from various food distributers in Lithuania. Aerobic colony count requirement was not met in 35% of the samples (EC) No (1441/2007). E. coli was also found in 35% of the minced meat samples. An antimicrobial resistance study, by determining the minimum inhibitory concentration (MIC) of E. coli growth, using the Liofilchem® E test strips with 14 different antimicrobial agents, was performed. All tested E. coli isolates were susceptible to F, CRO, MRP, IMI, FOS, CN, ATM and AK. Partial resistance occurred in PX, CIP, SAM, AMC, SXT and TE, with percentages ranging from 12.5% up to 87.5%. In total, 37.5% of E. coli isolates were confirmed as multi-drug resistant.

Background: Staphylococcus aureus is an important pathogen associated with mastitis in dairy cattle and foodborne infections in humans (1). The emergence of antimicrobial-resistant strains poses a significant threat to animals and public health (1). Farm environments may serve as reservoirs for resistant bacteria, facilitating their spread within the food chain (2). This study aimed to evaluate the prevalence of Staphylococcus aureus in the environment of dairy cattle farms and to determine the antimicrobial resistance of the isolates. Methods: The study was carried out in 2025-2026 at the Microbiology Laboratory of the Department of Food Safety and Quality, Lithuanian University of Health Sciences. In total, 120 environmental swab samples were previously collected from six Lithuanian dairy cattle farms. From these samples, 35 Staphylococcus spp. isolates stored in the laboratory collection were used for further analysis. The isolates originated from four environmental sources: bedding, feeding alleys, milking parlors and calf pens. The isolates were stored at -80 °C and subcultured on tryptone soy agar (Biolife, Italy), followed by incubation at 37 °C for 24 h under aerobic conditions. Coagulase tests using rabbit plasma (Biolife, Italy) and a latex agglutination kit (Microgen Bioproducts, UK) were performed to identify coagulase-positive staphylococci. Species identification of S. aureus was confirmed by PCR targeting the nucA gene. Antimicrobial susceptibility testing of confirmed S. aureus isolates was performed using the disk diffusion method on Mueller-Hinton agar (bioMérieux, France) according to EUCAST guidelines, and the results were interpreted based on EUCAST breakpoints. The tested antimicrobial agents included amoxicillin, amoxicillin/clavulanic acid, cefotaxime, ceftriaxone, cefpodoxime, cefoxitin, ciprofloxacin, amikacin, gentamicin and tetracycline. The presence of the mecA gene was determined by PCR. The data were analyzed using Microsoft Office Excel 2010 and SPSS software. Results: In total, 35 Staphylococcus spp. isolates were obtained from 29.16% of environmental swab samples collected in six dairy cattle farms. Coagulase-positive staphylococci accounted for 45.71% (16) of all isolates, while 54.29% (19) were coagulase-negative. PCR identification showed that 87.5% (14) of coagulase-positive isolates were confirmed as Staphylococcus aureus, representing 40% (14) of all staphylococcal isolates. S. aureus was detected in all six investigated farms, with the highest occurrence in calf pen samples. The distribution of S. aureus was significantly associated with the sampling location (p<0.05). Antimicrobial susceptibility testing of 14 S. aureus isolates showed that 78.57% (11) were susceptible to all tested antimicrobial agents, while 21.43% (3) were resistant to at least one antimicrobial. The highest resistance was observed to tetracycline, with 21.43% (3) resistant isolates. Multidrug resistance was confirmed in 7.14% (1) of isolates, resistant to β-lactams, aminoglycosides and tetracyclines. PCR analysis showed that the mecA gene was not detected in any of the tested S. aureus isolates (0%). Conclusion: Staphylococcus aureus was widely distributed in the dairy farm environment, particularly in calf pens. Although most isolates were susceptible to tested antimicrobials, resistant and multidrug-resistant strains were detected. These findings highlight the importance of monitoring farm environments as potential reservoirs of antimicrobial-resistant bacteria and implementing appropriate hygiene and antimicrobial stewardship measures.

Campylobacter jejuni (EFSA’s priority foodborne pathogen) and Listeria monocytogenes (a resilient seafoodassociated threat) pose critical food safety risks. This research evaluates Lactobacillus helveticus (L. helveticus), Lacticaseibacillus paracasei (L. paracasei), and acid whey (AW) for enhancing the safety of marinated poultry and salmon fillets. In broiler wings, the combination of L. helveticus and AW decreased C. jejuni numbers by 1.56 log₁₀ CFU/g while L. helveticus alone showed a significant effect (2.55 log₁₀ CFU/g reduction) in broiler fillets by day 5. After inoculation, L. paracasei survived well in broiler fillets (8.10 log₁₀ CFU/g, day 5), while AW promoted the growth of Lactobacillus in the wings (7.32 log₁₀ CFU/g, day 5), which assisted in the inhibition of C. Jejuni counts. The combination of L. helveticus and AW had a substantial reduction of aerobic mesophilic bacteria in wings, while AW alone had a similar effect on fillets (P < 0.05). In salmon fillets, L. helveticus with AW inhibited L. monocytogenes by 0.30 log₁₀ CFU/g on day 5 for the samples without skin (P < 0.05). This combination also increased lactic acid bacteria in skinless samples by day 5, contributing to L. monocytogenes reduction. Additionally, L. helveticus and AW decreased aerobic mesophilic bacterial count by 1.11 log₁₀ CFU/g in the samples without skin by day 5 (P < 0.05). This study uses a combination of lactic acid bacteria exhibiting probiotic properties and AW to provide a potential way to decrease C. jejuni and L. monocytogenes, thus improving food safety.

Campylobacter jejuni (EFSA’s priority foodborne pathogen) and Listeria monocytogenes (a resilient seafood-associated threat) pose critical food safety risk. This research aims to evaluate natural antimicrobials, Lactobacillus helveticus (L. helveticus), Lacticaseibacillus paracasei (L. paracasei), and acid whey (AW) for enhanced safety of marinated poultry, and salmon fillets. For poultry, L. helveticus + AW reduced C. jejuni by 30 % in the wings and 44 % in the fillets by day 5. In fillets, L. paracasei worked towards improving lactic acid bacteria (LAB) by day 3 and acid whey alone showed maximum efficiency in lowering pathogen load in wings, with the maximum impact being seen on day 5. The association of L. helveticus and acid whey significantly decreased aerobic mesophilic bacteria in wings. In contrast, acid whey alone showed the same effects in fillets. In salmon fillets, L. helveticus reduced the count of L. monocytogenes by 1.8 log₁₀ CFU/g (day 3) and 1.81 log₁₀ CFU/g (day 5) compared to the control (p < 0.05), while in lactic acid AW decreased counts by 1.15 log₁₀ CFU/g (p < 0.05). Moreover, the count of aerobic mesophiles in salmon fillets reduced by 1.01 log₁₀ CFU/g on day 5 (p < 0.05) using L. helveticus. These findings highlight the dual use of probiotics and acid whey in controlling pathogen and preserving quality. By focusing on C. jejuni and L. monocytogenes, these natural applications are enhancing the food safety while reducing the costs associated with foodborne disease.

Campylobacter jejuni (C. jejuni) is the primary Campylobacter species and a major cause of foodborne illness associated with poultry products. This review focuses on lactic acid bacteria (LAB), especially Lactobacillus species, and acid whey as a dairy by-product for C. jejuni control in poultry as a sustainable method. LAB strains L. crispatus exhibit a cecal colonization reduction of >90% by competitive exclusion and bacteriocin activity, while L. johnsonii FI9785 decrease bacterial load 4–5 log10. Acid whey, which is abundant in organic acids (e.g., lactic acid) and bioactive peptides (e.g., lactoferrin), reduces C. jejuni viability, decreasing the food product contamination on the carcass for a short time by 40%. LAB antimicrobial function becomes more effective when used with acid whey, although specific farm-related variables require additional optimization. Some of the key strategies include co-encapsulating LAB with acid whey or plant-derived antimicrobials for improving survival, conducting in vivo trials in commercial farm conditions to evaluate scalability, and adding whey into feed (1–2% inclusion) or applying it as a pre-slaughter spray. These strategies enable the antibiotic-free production and circular economy goals through repurposing low-cost acid whey. Future studies should directly compare them with standard antimicrobials to confirm their scalability for poultry safety.

The demand for healthy foods without artificial food additives is constantly increasing. Hence, natural food preservation methods using bioprotective cultures could be an alternative to chemical preservatives. Thus, the main purpose of this work was to screen the indigenous lactobacilli isolated from fermented cow milk for their safety and antifungal activity to select the safe strain with the strongest fungicidal properties for the development of bioprotective acid whey protein concentrate (AWPC) based fermentates and their coatings intended for fresh cheese quality maintenance. Therefore, 12 lactobacilli strains were isolated and identified from raw fermented cow milk as protective cultures. The safety of the stains was determined by applying antibiotic susceptibility, haemolytic and enzymatic evaluation. Only one strain, Lacticaseibacillus paracasei A11, met all safety requirements and demonstrated a broad spectrum of antifungal activity in vitro. The strain was cultivated in AWPC for 48 h and grew well (biomass yield 8 log10 cfu mL−1). L. paracasei A11 AWPC fermentate was used as a vehicle for protective culture in the development of pectin-AWPC-based edible coating. Both the fermentate and coating were tested for their antimicrobial properties on fresh acid-curd cheese. Coating with L. paracasei A11 strain reduced yeast and mould counts by 1.0–1.5 log10 cfu mL−1 (p ≤ 0.001) during cheese storage (14 days), simultaneously preserving its flavour and prolonging the shelf life for six days.

Spread of antibiotic resistance via mobile genetic elements associates with transfer of genes providing resistance against multiple antibiotics. Use of various comparative genomics analysis techniques enables to find intrinsic and acquired genes associated with phenotypic antimicrobial resistance (AMR) in Campylobacter jejuni genome sequences with exceptionally high-level multidrug resistance. In this study, we used whole genome sequences of seven C. jejuni to identify isolate-specific genomic features associated with resistance and virulence determinants and their role in multidrug resistance (MDR). All isolates were phenotypically highly resistant to tetracycline, ciprofloxacin, and ceftriaxone (MIC range from 64 to 256 g/mL). Besides, two C. jejuni isolates were resistant to gentamicin, and one was resistant to erythromycin. The extensive drug-resistance profiles were confirmed for the two C. jejuni isolates assigned to ST-4447 (CC179). The most occurring genetic antimicrobial-resistance determinants were tetO, beta-lactamase, and multidrug efflux pumps. In this study, mobile genetic elements (MGEs) were detected in genomic islands carrying genes that confer resistance to MDR, underline their importance for disseminating antibiotic resistance in C. jejuni. The genomic approach showed a diverse distribution of virulence markers, including both plasmids and phage sequences that serve as horizontal gene transfer tools. The study findings describe in silico prediction of AMR and virulence genetics determinants combined with phenotypic AMR detection in multidrug-resistant C. jejuni isolates from Lithuania.

Antibiotics are widely administered to farm animals to treat and prevent infectious diseases, or as food supplements. This use of antibiotics is recognized as a major cause of antibiotic resistance in bacteria’s (like, Stahylococcus spp. and others) colonizing the digestive tract of domestic animals (1). Most of the resistant bacteria found in these animals can be transmitted to humans through contact with them or through contaminated food products (such as milk or other dairy products) and environment (untreated water or contaminated objects). The aim of this study was to establish the prevalence and antimicrobial resistance of Staphylococcus spp. bacteria isolated from cattle farm environment. The study was carried out in 2019, in three Lithuanian dairy cattle farms. In total, 60 swab samples were taken from four different sources (calf and cattle bedding, feeding area and milking equipment). For Staphylococcus spp. isolation and identification Manitol salt agar (Biolife, Italy), Baird-Parker agar (Biolife, Italy) and Microgen Staph ID test (Microgen Bioproducts, England) were used. Additional confirmation of Stahylococcus aureus (S. aureus) was done by PCR during nucA gene identification (2). Eighteen Staphylococcus spp. strains resistance to 5 antimicrobial agents (amoxicillin, tetracycline, ciprofloxacin, streptomycin and ceftriaxone) were determined using E-test (Epsilometer test). The results were evaluated according EUCAST 2019 antimicrobial susceptibility breakpoint guidelines. In total, 48 staphylococcus strains were isolated from 80% of the environmental swab samples. S. aureus (14.3%), Staphylococcus haemolyticus (11.4%) and Staphylococcus schleiferi (5.7%) were the most prevalent species among the isolated staphylococci. Seven bacterias were confirmed as S. aureus by PCR. In this study, most common Staphylococcus spp. were isolated from the samples of calves bedding (39.5%) and feeding areas ...[...].

A variety of foods and environmental sources harbour bacteria that are resistant to one or more antimicrobial drugs used in medicine and agriculture. Antibiotic resistance in Escherichia coli is of particular concern because it is one of the most common Gram-negative pathogen in humans [1.]. Raw milk can be contaminated with E. coli during clinical mastitis and either directly through animal faeces or indirectly during milk collection through farm employees or the milking equipment [2.]. The aim of this study was to determine the antimicrobial resistance of E. coli bacteria isolated from raw milk of cows and milk products (curd). In total, 21 samples from seven different dairy cattle farms located in Lithuania were tested for E. coli during the period of September and December, in 2019. Additionally, 3 curd samples collected from different local farmers were tested. E. coli bacteria were isolated using Chromogenic coliform agar (Biolife, Italy) and Tryptic soy agar (Biolife, Italy). The morphology of the bacteria was checked by performing Gram staining. All typical E. coli strains were additionally identified with multiplex PCR by the detection of upsA and uidA genes as described by Godambe et al. 2017. Antimicrobial susceptibility for amoxicillin (AML), gentamicin (CN), kanamycin (K), tetracycline (TET) and chloramphenicol (C) was tested on 13 E. coli strains isolated from raw milk of cows and curd using MIC strip tests (Liofilchem, Italy). The results were interpreted according to CLSI 2019 and NARMS 2019 antimicrobial susceptibility breakpoint guidelines. E. coli was found in 47.2 % of the tested raw cow milk and 100% curd samples. The antimicrobial resistant testing revealed that all (13) tested E. coli strains were susceptible to all tested antibiotics. The detected minimum inhibitory concentration (MIC) varied from 1 μg/mL to 32 μg/mL for AML, from 0.25 μg/mL to 16 μg/mL for CN, , from 8 μg/mL to...[...].

Antimicrobial resistance of different bacteria has become a major issue in public health worldwide. Escherichia coli is one of many bacteria that can develope resistance. Most strains of E. coli are nonpathogenic comensals that form a part of natural microflora in the digestive tract of dairy cattle, but pathogenic strains also occur [1]. Consumption of unpasteurised milk and milk products, contaminated with such pathogenic E. coli, can lead to various health problems in humans. Moreover, if bacteria causing the infection is resistant to antibiotics, treatment can be even more complex [2]. The aim of this study was to evaluate antimicrobial resistance of E. coli bacteria isolated from dairy cattle farm environment. Altogether three dairy cattle farms located in Lithuania were tested during the period of April and May, in 2019. In total, 60 swab samples from four different surfaces (cows beddings, calves beddings, feeding area and milking parlours) on each farm were collected. E. coli bacteria were isolated using Chromogenic coliform agar (Biolife, Italy) and Tryptic soy agar (Biolife, Italy). The morphology of the bacteria was checked by performing Gram staining. All typical E. coli strains were additionaly indentified with multiplex PCR by the detection of upsA and uidA genes as described by Godambe et al. 2017 [3]. Altogether 18 E. coli strains (six isolates from each farm) were tested to antimicrobial susceptibility for amoxicilin (AML), ceftriaksone (CRO), tetracycline (TET), ciprofloxacin (CIP) and streptomycin (STR) using MIC strip tests (Liofilchem, Italy). The results were interpreted according to CLSI 2019 and NARMS 2019 antimicrobial susceptibility breakpoint guidelines. In total, 38.3% of the environmental surface samples were E. coli positive. Most often bacteria were found in swab samples of cows and calves’ beddings (73.3% and 66.7%, respectively). In total, 44 E. coli strains were isolated ...[...].