Integrative and Conjugative Elements and Prophage DNA as Carriers of Resistance Genes in Erysipelothrix rhusiopathiae Strains from Domestic Geese in Poland.

Goose erysipelas is a serious problem in waterfowl breeding in Poland. However, knowledge of the characteristics of Erysipelothrix rhusiopathiae strains causing this disease is limited. In this study, the antimicrobial susceptibility and serotypes of four E. rhusiopathiae strains from domestic geese were determined, and their whole-genome sequences (WGSs) were analyzed to detect resistance genes, integrative and conjugative elements (ICEs), and prophage DNA. Sequence type and the presence of resistance genes and transposons were compared with 363 publicly available E. rhusiopathiae strains, as well as 13 strains of other Erysipelothrix species. Four strains tested represented serotypes 2 and 5 and the MLST groups ST 4, 32, 242, and 243. Their assembled circular genomes ranged from 1.8 to 1.9 kb with a GC content of 36-37%; a small plasmid was detected in strain 1023. Strains 1023 and 267 were multidrug-resistant. The resistance genes detected in the genome of strain 1023 were erm47, tetM, and lsaE-lnuB-ant(6)-Ia-spw cluster, while strain 267 contained the tetM and ermB genes. Mutations in the gyrA gene were detected in both strains. The tetM gene was embedded in a Tn916-like transposon, which in strain 1023, together with the other resistance genes, was located on a large integrative and conjugative-like element of 130 kb designated as ICEEr1023. A minor integrative element of 74 kb was identified in strain 1012 (ICEEr1012). This work contributes to knowledge about the characteristics of E. rhusiopathiae bacteria and, for the first time, reveals the occurrence of erm47 and ermB resistance genes in strains of this species. Phage infection appears to be responsible for the introduction of the ermB gene into the genome of strain 267, while ICEs most likely play a key role in the spread of the other resistance genes identified in E. rhusiopathiae.

Bacteriophages for Controlling Staphylococcus spp. Pathogens on Dairy Cattle Farms: In Vitro Assessment.

Pathogenic Staphylococcus spp. strains are significant agents involved in mastitis and in skin and limb infections in dairy cattle. The aim of this study was to assess the antibacterial effectiveness of bacteriophages isolated from dairy cattle housing as potential tools for maintaining environmental homeostasis. The research will contribute to the use of phages as alternatives to antibiotics. The material was 56 samples obtained from dairy cows with signs of limb and hoof injuries. Staphylococcus species were identified by phenotypic, MALDI-TOF MS and PCR methods. Antibiotic resistance was determined by the disc diffusion method. Phages were isolated from cattle housing systems. Phage activity (plaque forming units, PFU/mL) was determined on double-layer agar plates. Morphology was examined using TEM microscopy, and molecular characteristics were determined with PCR. Among 52 strains of Staphylococcus spp., 16 were used as hosts for bacteriophages. Nearly all isolates (94%, 15/16) showed resistance to neomycin, and 87% were resistant to spectinomycin. Cefuroxime and vancomycin were the most effective antibiotics. On the basis of their morphology, bacteriophages were identified as class Caudoviricetes, formerly Caudovirales, families Myoviridae-like (6), and Siphoviridae-like (9). Three bacteriophages of the family Myoviridae-like, with the broadest spectrum of activity, were used for further analysis. This study showed a wide spectrum of activity against the Staphylococcus spp. strains tested. The positive results indicate that bacteriophages can be used to improve the welfare of cattle.

Characterization of Riemerella anatipestifer Strains Isolated from Various Poultry Species in Poland.

Riemerella anatipestifer (R. anatipestifer) is one of the common pathogens found in poultry flocks, resulting in serious economic losses for the poultry industry due to high mortality, reduced growth rate, poor feed conversion, increased condemnations, and high treatment costs. The aim of this study was to phenotypically characterize phylogenetic relationships and assess the presence of resistance gene strains of R. anatipestifer obtained from various poultry species in Poland. A total of 57 isolates of Riemerella were included in this study. A polymerase chain reaction (PCR) and matrix assisted laser desorption ionization mass spectrometry (MALDI-TOF MS) were used for identification of the strains. The phylogenetic relationship of the R. anatipestifer isolates was determined by analysing the rpoB gene sequence. The susceptibility to antibiotics was evaluated by minimum inhibitory concentration (MIC) in liquid media. All of the field strains of R. anatipestifer were grouped into one of two clades resulting from rpoB gene sequencing. High MIC50 and MIC90 values were obtained for gentamycin, amikacin, and colistin. Low MIC50 and MIC90 values were obtained for amoxicillin cefuroxime, cefoperazone, piperacillin, and trimethoprim/sulfamethoxazole. Among the resistance genes, tet(X) and ermF were identified most frequently. This is the first phenotypic characterization of R. anatipestifer strains obtained from poultry flocks in Poland.

Determination of Anti-phage Antibodies in Calf Sera Following Application of Escherichia Coli and Mannheimia Haemolytica-specific Bacteriophages.

Introduction: The widespread occurrence of drug-resistant bacteria has increased interest in alternatives to antibiotics for combatting bacterial infections, among which bacteriophages play an important role. The ability of phage proteins to induce an anti-phage immune response can significantly limit the effectiveness of treatment, which was the basis for the study described in this article. The aim of the study was to assess the effects of bacteriophages on the induction of an anti-phage humoral response in calves. Material and Methods: The study was conducted using phage components of experimental preparations and sera from calves treated and not treated with phages. Levels of G, M and A immunoglobulins were analysed by ELISA. The assay plates were coated with whole Escherichia coli and Mannheimia haemolytica phages and selected phage proteins obtained in sodium dodecyl sulphate-polyacrylamide gel electrophoresis and two-dimensional electrophoresis. Neutralisation of phages by immunoglobulins was assessed by determining phage titres using double-layer plates. Results: The results confirmed an increased anti-phage response affecting all immunoglobulin classes in the calf sera. The highest significant (P ≤ 0.05) level of antibodies was observed for IgG in the sera of calves receiving phages. The phage neutralisation test showed a significant differences (P ≤ 0.05) in the reduction of phage titres in comparison to untreated calves. Conclusion: Despite the induction of an anti-phage response, no significant negative effect on the antibacterial activity of phages was observed in vitro.

Antimicrobial Resistance and Virulence Genes in Staphylococci Isolated from Aviary Capercaillies and Free-living Birds in South-eastern Poland.

Introduction: The current study characterises Staphylococcus bacteria recovered from dead free-living birds and captive capercaillies kept in south-eastern Poland. The results provide novel information about the antimicrobial resistance phenotype/genotype and the virulence profile of these bacteria. Material and Methods: Samples of internal organs were taken from dead birds. Staphylococcus strains were identified by matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry. Susceptibility to 13 antibiotics was tested using a standard disc diffusion method on Mueller-Hinton agar. All isolates were screened for the presence of antibiotic resistance genes and staphylococcal enterotoxins (A to E), toxic shock syndrome toxin 1, exfoliative toxins A and B and Panton-Valentine leukocidin. Results: A total of 129 bacterial strains belonging to 19 species of the Staphylococcus genus were isolated. A relatively high percentage of them resisted fluoroquinolones, tetracyclines, macrolides and ß-lactams to a significant degree and harboured the tetK, tetM, ermC, mphC and mecA genes. Strains of the coagulase-negative S. sciuri, S. xylosus and S. cohnii were isolated with genes encoding enterotoxin A and toxic shock syndrome toxin. Conclusion: Both coagulase-positive and coagulase-negative staphylococci isolated from aviary capercaillies and free-living birds have significant pathogenic potential, and greater attention must be paid to the coagulase-negative species, which are still often considered mere contaminants. Virulence factors associated with resistance to antimicrobials, this being multiple in some strains, seem most important because they can be easily transferred between animals, especially those living in a given area.

Pet Reptiles in Poland as a Potential Source of Transmission of Salmonella.

Reptiles are considered a potential source of Salmonella transmission to humans. The aim of this research was to determine the incidence of Salmonella in pet reptiles in Poland and to examine Salmonella isolates with regard to their biochemical characteristics, serotype, antimicrobial susceptibility, and pathogenic and zoonotic potential. The research material consisted of 67 reptile faeces samples. The taxonomic affiliation of the Salmonella isolates was determined by MALDI-TOF mass spectrometry, biochemical analyses, and serotyping; whole genome sequencing (WGS) analysis was performed on three isolates whose serotype could not be determined by agglutination. The antimicrobial susceptibility of the Salmonella isolates was determined by the broth dilution method, and in the case of some antimicrobials by the disk diffusion method. The pathogenic and zoonotic potential of the identified serotypes was estimated based on available reports and case studies. The presence of Salmonella was confirmed in 71.6% of faecal samples, with the highest incidence (87.1%) recorded for snakes, followed by lizards (77.8%) and turtles (38.9%). All isolates (n = 51) belonged to the species S. enterica, predominantly to subspecies I (66.7%) and IIIb (25.5%). Among these, 25 serotypes were identified, including 10 that had previously been confirmed to cause reptile-associated salmonellosis (RAS). Salmonella isolates were susceptible to all antimicrobial substances used except streptomycin, to which 9.8% of the strains showed resistance. None of the strains contained corresponding resistance genes. The study demonstrates that pet reptiles kept in Poland are a significant reservoir of Salmonella and contribute to knowledge of the characteristics of reptilian Salmonella strains. Due to the risk of salmonellosis, contact with these animals requires special hygiene rules.

Antibiotic Resistance in Bacteria-A Review.

BACKGROUND: A global problem of multi-drug resistance (MDR) among bacteria is the cause of hundreds of thousands of deaths every year. In response to the significant increase of MDR bacteria, legislative measures have widely been taken to limit or eliminate the use of antibiotics, including in the form of feed additives for livestock, but also in metaphylaxis and its treatment, which was the subject of EU Regulation in 2019/6. Numerous studies have documented that bacteria use both phenotypis and gentic strategies enabling a natural defence against antibiotics and the induction of mechanisms in increasing resistance to the used antibacterial chemicals. The mechanisms presented in this review developed by the bacteria have a significant impact on reducing the ability to combat bacterial infections in humans and animals. Moreover, the high prevalence of multi-resistant strains in the environment and the ease of transmission of drug-resistance genes between the different bacterial species including commensal flora and pathogenic like foodborne pathogens (E. coli, Campylobacter spp., Enterococcus spp., Salmonella spp., Listeria spp., Staphylococcus spp.) favor the rapid spread of multi-resistance among bacteria in humans and animals. Given the global threat posed by the widespread phenomenon of multi-drug resistance among bacteria which are dangerous for humans and animals, the subject of this study is the presentation of the mechanisms of resistance in most frequent bacteria called as "foodborne pathoges" isolated from human and animals. In order to present the significance of the global problem related to multi-drug resistance among selected pathogens, especially those danger to humans, the publication also presents statistical data on the percentage range of occurrence of drug resistance among selected bacteria in various regions of the world. In addition to the phenotypic characteristics of pathogen resistance, this review also presents detailed information on the detection of drug resistance genes for specific groups of antibiotics. It should be emphasized that the manuscript also presents the results of own research i.e., Campylobacter spp., E. coli or Enetrococcus spp. This subject and the presentation of data on the risks of drug resistance among bacteria will contribute to initiating research in implementing the prevention of drug resistance and the development of alternatives for antimicrobials methods of controlling bacteria.

Virulence Profiles and Antibiotic Susceptibility of Escherichia coli Strains from Pet Reptiles.

Exotic reptiles are increasingly being bred as pets in many countries around the world, including Poland. However, the close contact between reptiles and their owners provides favourable conditions for the transmission of zoonotic pathogens. In this work, we examined E. coli isolates from 67 captive reptiles regarding their virulence, antibiotic susceptibility, phylogenetic affiliation, and genetic diversity. The incidence of E. coli was highest in snakes (51.6%, 16 isolates/31 samples), and slightly lower in turtles (44.4%, 8/18) and lizards (44.4%, 8/18). Genes encoding virulence factors were confirmed in 50% of isolates and the most common were the traT (37.5%, n = 12), fyuA (21.87%, n = 7), and irp-2 (15.62%, n = 5). The majority (71.87%, n = 23) of E. coli isolates were susceptible to all of the antimicrobial substances used in the study. Streptomycin resistance (21.87%, n = 7) was the most frequent, while resistance to other antimicrobial substances was sporadic. One strain (3.12%) was classified as multidrug-resistant. The presence of resistance genes (aadA, tetA, tetB, tetM, and blaTEM) was confirmed in 12.5% (n = 4) of the isolates. The majority (65.6%, n = 21) of E. coli isolates represented the B1 phylogenetic group. (GTG)5-PCR fingerprinting showed considerable genetic variation in the pool of tested isolates. The frequency of E. coli in reptiles is much lower than in mammals or birds. Due to the presence of virulence genes, characteristic of both intestinal pathogenic E. coli (IPEC) and extraintestinal pathogenic E. coli (ExPEC), reptilian strains of E. coli have pathogenic potential, and therefore people in contact with these animals should follow good hygiene practices.

Bacteriophages as an Alternative Method for Control of Zoonotic and Foodborne Pathogens.

The global increase in multidrug-resistant infections caused by various pathogens has raised concerns in human and veterinary medicine. This has renewed interest in the development of alternative methods to antibiotics, including the use of bacteriophages for controlling bacterial infections. The aim of this review is to present potential uses of bacteriophages as an alternative to antibiotics in the control of bacterial infections caused by multidrug-resistant bacteria posing a risk to humans, with particular emphasis on foodborne and zoonotic pathogens. A varied therapeutic and immunomodulatory (activation or suppression) effect of bacteriophages on humoral and cellular immune response mechanisms has been demonstrated. The antibiotic resistance crisis caused by global antimicrobial resistance among bacteria creates a compelling need for alternative safe and selectively effective antibacterial agents. Bacteriophages have many properties indicating their potential suitability as therapeutic and/or prophylactic agents. In many cases, bacteriophages can also be used in food quality control against microorganisms such as Salmonella, Escherichia coli, Listeria, Campylobacter and others. Future research will provide potential alternative solutions using bacteriophages to treat infections caused by multidrug-resistant bacteria.

Characterization and Comparison of Enterococcus spp. Isolates from Feces of Healthy Dogs and Urine of Dogs with UTIs.

Enterococcus spp. are opportunistic pathogens of both humans and animals characterized by high resistance to antimicrobials. Dogs could be intestinal carriers or suffer from Enterococcus infections, mainly urinary tract infections (UTIs). This study aimed to analyze and compare Enterococcus spp. isolated from healthy dog stools and sick dog urine. Overall, 51 isolates (29 from stools and 22 from UTI) were characterized at species level and tested for antimicrobial resistance, biofilm production and presence of resistance and virulence genes. E. faecium and E. faecalis resulted as equally distributed in stools samples, while E. faecalis predominated among UTI isolates. HLAR phenotype was detected in 47.1% isolates; 64.7% isolates were resistant to ampicillin (47.1% with a MIC ≥ 64 µg/mL). High levels of resistance were recorded for fluoroquinolones (enrofloxacin 74.5%, ciprofloxacin 66.7%), clindamycin (84.3%), tetracycline (78.4%) and quinupristin-dalfopristin (78.4%). No vancomycin resistant strains were detected. All but one isolate were multidrug-resistant. Most detected resistance genes were tetM (70.5%), pbp4 (52.9%) and aph(3')-IIIa (39.2%). All isolates were able to produce biofilm, but isolates from UTIs and belonging to E. faecalis more frequently resulted in strong biofilm producers. Most detected virulence genes were asa1 (52.9%), gelE (41.2%), cylA (37.3%) and esp (35.3%); all of them resulted as more frequently associated to E. faecalis. No particular differences emerged between isolates from feces and UTI, considering all evaluated aspects. Our results confirm pet dogs as carriers of multidrug-resistant enterococci; stool microflora could be considered as the most probable source of enterococcal UTI and E. faecalis carried by dogs seems to be more virulent than E. faecium, justifying its more frequent involvement in urinary tract infections.

The presence of pathogens and heavy metals in urban peregrine falcons (Falco peregrinus).

BACKGROUND AND AIM: Wild birds raised in urban environments may be exposed to many negative factors, including biological and chemical toxic elements. The aim of the study was to assess the occurrence of bacteria and parasites in wild birds, based on the example of the peregrine falcon (Falco peregrinus) as a potential indicator of bacterial drug resistance genes. Toxicological contamination was also analyzed to determine the impact of urbanized areas on this predatory species, in terms of its health, welfare, and survival in urban environments. MATERIALS AND METHODS: The samples consisted of down feathers and fresh feces obtained from seven falcon chicks (during obligatory veterinary examination) reared in two nests located in the Lublin region (Lublin and Pulawy). Bacteria and parasites were isolated directly from feces by classical microbiological methods, polymerase chain reaction, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MS). The down feathers and feces of birds were used for toxicological testing by plasma inductively coupled plasma MS to assess the concentrations of selected heavy metals (cadmium [Cd], lead [Pb], arsenic [As], zinc [Zn], and copper [Cu]). RESULTS: The study revealed the presence of a diverse microbiome in the falcon chicks, among which Escherichia coli, Enterococcus spp., and Staphylococcus spp. bacteria and parasites of the genus Caryospora were dominant. The presence of drug resistance genes was also confirmed among the pathogens. The toxicological analysis found high concentrations of toxic heavy metals, including Cd, Pb, As, and Zn, in the downy feathers and feces of peregrine chicks. CONCLUSION: Predatory free-living birds living in urban environments not only can be infected with various pathogens but may also show contamination with heavy metals, which could influence their natural resistance, condition, and welfare.

Antibiotic Resistance and Virulence Profiles of Escherichia coli Strains Isolated from Wild Birds in Poland.

Wild animals are increasingly reported as carriers of antibiotic-resistant and pathogenic bacteria including Enterobacteriaceae. However, the role of free-living birds as reservoirs for potentially dangerous microbes is not yet thoroughly understood. In our work, we examined Escherichia coli strains from wild birds in Poland in relation to their antimicrobial agents susceptibility, virulence and phylogenetic affiliation. Identification of E. coli was performed using MALDI-TOF mass spectrometry. The antibiotic susceptibility of the isolates was determined by the broth microdilution method, and resistance and virulence genes were detected by PCR. E. coli bacteria were isolated from 32 of 34 samples. The strains were most often classified into phylogenetic groups B1 (50%) and A (25%). Resistance to tetracycline (50%), ciprofloxacin (46.8%), gentamicin (34.3%) and ampicillin (28.1%) was most frequently reported, and as many as 31.2% of E. coli isolates exhibited a multidrug resistance phenotype. Among resistance genes, sul2 (31.2% of isolates) and blaTEM (28.1%) were identified most frequently, while irp-2 (31.2%) and ompT (28.1%) were the most common virulence-associated genes. Five strains were included in the APEC group. The study indicates that wild birds can be carriers of potentially dangerous E. coli strains and vectors for the spread of resistant bacteria and resistance determinants in the environment.

Biodiversity of Ligilactobacillus salivarius Strains from Poultry and Domestic Pigeons.

Ligilactobacillus salivarius is an important member of the human and animal gut microbiota, and selected strains are promising probiotics, but knowledge of the characteristics of avian isolates is still limited. In this study, we examined selected phenotypic and genotypic traits of 33 L. salivarius strains from geese, chickens, turkeys and pigeons. The strains varied in terms of cell size, colony morphology, broth growth characteristics, biofilm formation, tolerance to bile, hydrophobicity and phenotypic and genotypic antibiotic resistance profiles. Large variation among strains was noted for the utilization of sorbitol, salicin, trehalose, rhamnose, inulin and N-acetyl-D-glucosamine. The presence of genes related to sugar metabolism, i.e., mipB, tktA, rhaB and LSL_1894, was not always correlated with the biochemical phenotypic profile. Correlations were recorded between the host and utilization of certain sugars as well as tolerance to bile. The repA-type megaplasmid and genes coding for Abp118 bacteriocin were detected in 94% and 51.5% of L. salivarius strains, respectively. Phylogeny based on groEL gene sequences was partly correlated with the origin of the strains and revealed an evolutionary distance between L. salivarius strains from humans and birds. The results of the study contribute to knowledge of the characteristics of the species L. salivarius. Intraspecies variations of L. salivarius strains may affect their ability to colonize specific niches and utilize nutrients and reveal potential strain-dependent effects on host health.

Therapeutic and Prophylactic Effect of the Experimental Bacteriophage Treatment to Control Diarrhea Caused by E. coli in Newborn Calves.

The prevalence of antibiotic-resistant bacteria causing neonatal diarrhea in calves has become a serious problem in the control of infection. Due to increasing antibiotic resistance, bacteriophages with probiotics are considered the best alternative. The aim of the study was to evaluate the use of a suppository containing probiotic strains of Lactobacillus spp. and bacteriophages specific for pathogenic E. coli in young calves with diarrhea. The study evaluated therapeutic and prophylactic effects (specific and nonspecific humoral response). The study was carried out on 24 female HF calves, aged 2 to 7 days and weighing from 35 to 46 kg. The calves were divided into four groups (n = 6) as follows: Group 1, healthy control that received no medicine; Group 2, positive control with diarrhea; Group 3, healthy calves that received medicine; Group 4, calves with diarrhea that received medicine. The animals received suppositories containing Lactobacillus spp. and bacteriophages specific for pathogenic E. coli for 5 days. On the first day, the calves received the suppositories twice-in the morning and 12 h later; subsequently they were administered once a day. The health status of the calves was observed for 11 days after the first application of suppositories. A protective and preventive effect of the experimental therapy was obtained in the research. The probiotic-phage suppositories reduced the duration of diarrhea in calves, completely eliminating it within 24-48 h after use. The therapy stimulated the activation of immune mechanisms in calves, which translated into an enhanced specific and nonspecific response and increased resistance to infection.

Phenotypic and genotypic characterization of Enterococcus spp. from yolk sac infections in broiler chicks with a focus on virulence factors.

Bacterial infections of yolk sacs contribute to increased mortality of chicks, chronic infections during their rearing, or increased selection in the flock, which in turn leads to high economic losses in poultry production worldwide. The aim of this study was a phenotypic and genotypic characterization of enterococci isolated from yolk sac infections (YSI) of broiler chickens from Poland and the Netherlands. Biochemical, matrix-assisted laser desorption/ionization (MALDI)-time-of-flight (TOF) MS, and rpoA gene sequencing identification was performed. Moreover, phenotypic and genotypic characterization of virulence factors and analysis of the clonal relationship of isolates by MALDI-TOF MS and enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) were performed. The biochemical test identified 70 isolates as Enterococcus faecalis and 6 as Enterococcus mundtii. The results of MALDI-TOF MS were 100% concordant with those obtained by rpoA gene sequencing, and all 76 isolates were identified as E. faecalis. Differences were noted in the ß-glucuronidase, ß-glucosidase, α-galactosidase, phosphatase, melibiose, lactose, and raffinose tests that is going about the results of biochemical identification. None of the isolates were beta-hemolytic on blood agar in aerobic conditions, but all but one were gelatinase positive. Among biofilm-forming isolates (30/76; 39.5%), as many as 66.7% (20/30) were Polish E. faecalis strains. Most of the isolates carried virulence genes, that is gelE, ace, asa1, efaAfs, fsrA, fsrB, fsrC, cob, cpd, and ccf, but none had the hyl gene. Some isolates harbored cyl operon genes. One Polish strain (ST16) had all of the tested cyl genes and the esp gene, considered clinically important, and showed the highest biofilm-forming ability. Nearly 50% of the isolates showed close genetic relatedness in ERIC typing. In contrast with MALDI-TOF MS cluster analysis, ERIC-PCR results did not show a relationship with the origin of the strains. Using MALDI-TOF MS, 7 peaks were found in Polish and Dutch isolates, which may type them as species-specific biomarkers in E. faecalis from YSI.

Experimental Phage Therapies in Companion Animals with A Historical Review.

BACKGROUND: The aim of the review was to comprehensively characterize the antimicrobial efficacy of bacteriophages in eliminating pathogens occurring in companion animals, as an alternative to antibiotics for controlling infections that pose potential threats to the health and life of people and to the environment. METHODS: The review contains detailed information on the characteristics and classification of bacteriophages and an analysis of their life cycle. The dominant element is a detailed analysis of the experimental use of bacteriophages in combating infections caused by various microorganisms in companion animals with regard to their potential use in therapy. RESULTS: It seems that in the near future, phage therapies will provide an alternative to antibiotics in the treatment of diseases caused by multi-drug resistant bacteria in people and animals. CONCLUSIONS: The effectiveness of phage therapies depends on many factors and the properties of the bacteriophages themselves, which requires comprehensive knowledge of them.

The in vitro efficacy of eye drops containing a bacteriophage solution specific for Staphylococcus spp. isolated from dogs with bacterial conjunctivitis.

BACKGROUND: The purpose of the study was to evaluate the in vitro antibacterial effect of experimental eye drops with bacteriophages in elimination of Staphylococcus spp. isolated from dogs with bacterial conjunctivitis.. The bacterial material was collected from dogs with independent clinical signs of bacterial conjunctivitis. Staphylococcus spp. were identified by phenotypic and genotypic methods (MALDI-TOF MS mass spectrometry). Antibiotic resistance was determined by the disc-diffusion method. Phage activity (Plaque forming units, PFU) was determined on double-layer agar plates. Phages with lytic titres > 108 PFU were used to prepare eye drops. The stability of the antibacterial titre was evaluated for preparations stored in sealed bottles as well as after opening and reclosing. RESULTS: The tests confirmed the occurrence of Staphylococcus spp. strains as etiological agents of bacterial conjunctivitis in dogs. A high percentage of strains were resistant to more than three antibiotics. The experimental phage eye drops used in the study exhibited 100% efficacy in vitro against the tested Staphylococcus isolates. Particularly noteworthy is the long duration of activity and constant antibacterial lytic titre of ≥108 PFU/mL of two eye drop solutions, nos. 7 and 12, after the bottle had been opened (21 days) and after hermetically sealed packaging (28 days) at 4-8 °C. CONCLUSIONS: The results represent the first stage of research and require continuation in vivo. If positive effects are obtained in animals, the results can be used in applied research in humans and animals.

Phenotypic and genotypic antimicrobial resistance profiles of fecal lactobacilli from domesticated pigeons in Poland.

Lactobacillus species play an important role in the host and although they are non-pathogenic, they could act as reservoirs for antibiotic resistance genes, with the potential risk of transfer to other bacteria inhabiting the gastrointestinal tract. The aim of this study was to identify Lactobacillus species derived from feces of domesticated pigeons and to characterize their phenotypic and genotypic antimicrobial resistance (AMR) profiles. A total of 57 Lactobacillus isolates were classified into six species using the MALDI-TOF technique and 16S rDNA restriction analysis. Strains of L. ingluviei (31%), L. salivarius (28%) and L. agilis (23%) were the dominant species isolated. Determination of antimicrobial susceptibility by the microdilution broth method showed widespread resistance to kanamycin (89%), tetracycline (84%), streptomycin (63%), and enrofloxacin (37%). Less than 30% of the isolates were resistant to erythromycin, lincosamides, gentamycin, chloramphenicol and vancomycin. Over half (51%) of the lactobacilli were classified as multidrug resistant. Tet genes were detected in 79% of isolates; the lnuA, cat, ermB, ermC, ant(6)-Ia, ant(4')-Ia, and int-Tn genes were found at a lower frequency. Sequence analysis of the quinolone resistance-determining region (QRDR)of the gyrA gene showed that fluoroquinolone resistance in lactobacilli was the result of a mutation that lead to a change in the amino acid sequence (Ser83→Tyr/Leu/Phe). Domesticated pigeons could be a reservoir for AMR Lactobacillus strains and AMR genes.

Efficacy of experimental phage therapies in livestock.

Bacteriophages are the most abundant form of life on earth and are present everywhere. The total number of bacteriophages has been estimated to be 1032 virions. The main division of bacteriophages is based on the type of nucleic acid (DNA or RNA) and on the structure of the capsid. Due to the significant increase in the number of multi-drug-resistant bacteria, bacteriophages could be a useful tool as an alternative to antibiotics in experimental therapies to prevent and to control bacterial infections in people and animals. The aim of this review was to discuss the history of phage therapy as a replacement for antibiotics, in response to EU regulations prohibiting the use of antibiotics in livestock, and to present current examples and results of experimental phage treatments in comparison to antibiotics. The use of bacteriophages to control human infections has had a high success rate, especially in mixed infections caused mainly by Staphylococcus, Pseudomonas, Enterobacter, and Enterococcus. Bacteriophages have also proven to be an effective tool in experimental treatments for combating diseases in livestock.

Susceptibility of chicken Lactobacillus bacteria to coccidiostats.

The aim of this study was to determine the susceptibility of Lactobacillus bacteria to selected coccidiostats. Seventy-five Lactobacillus isolates obtained from chickens were classified by MALDI-TOF mass spectrometry and 16S rDNA restriction analysis into seven species, among which L. salivarius (33%) and L. johnsonii (24%) were dominant. Susceptibility of lactobacilli to coccidiostats was determined by broth microdilution method. The ranges of minimum inhibitory concentrations (MICs) were 0.5-≥128 µg/ml for monensin, 0.125-8 µg/ml for salinomycin, ≤0.03-2 µg/ml for lasalocid A, and 4-16 µg/ml for robenidine. Coccidiostats in low concentrations inhibited in vitro growth of most lactobacilli and therefore there is a high probability that administration of this drugs to chickens would reduce the number of lactobacilli in the gut.