Yersiniosis outbreak in rainbow trout (Oncorhynchus mykis) at a fish farm from Northern Romania

Yersiniosis (Enteric diseases – red mouth) is a septicemic infectocontagious disease of salmonides, produced by Yersinia ruckeri, young rainbow trout being the most susceptible to infection. The disease appears as an exogenous or endogenous infection, influenced by favouring factors. The infection sources are represented by sick and asymptomatic carrier fishes that eliminate Yersinia through faeces, contaminating water and fodder. At the beginning of the disease outbreak, which is the subject of the present scientific paper, sudden water warming (15-17ºC) in the spring of 2008 was incriminated. The bacteriological examination carried out on the anterior kidney and heart blood from trout suspected of yersiniosis had as result the isolation of some Yersinia ruckeri bacteriological strains, confirming the suspected diagnosis, based on lesions (high degree anaemia of oral mucosa and branchia, haemorrhagia on tongue mucosa, exophthalmia and ocular haemorrhagia). The identification of the causative agent was based on morphological aspects (gramnegative, motile and rod-shaped) and distinctive metabolic characters, tested by using API galleries. Antibiogramas pointed out the Y. ruckeri strain susceptibility to Oxytetracicline, Flumequine, Trimethoprim and Ceftiofur and a medium susceptibility to Amoxicillin and Enrofloxacin

The Prevalence of Esbl-Producing Strains of E.coli, Isolated from Calves with Colibacilosis - Preliminary Remarks

The animals producing food have become an increasing reservoir of extended spectrum beta-lactamase producing Enterobacteriaceae. The calves and cows are exposed to a greater quantity of antibiotics, but the data concerning the prevalence of ESBL-producing Enterobacteriaceae are not enough, in comparison with other species of animals used for human consumption, such as birds (Hordijk et al., 2013).The aim of this study was to determine the prevalence of ESBL-producing E. coli involved in some episodes of colibacilosis in calves. Faeces samples were collected from 33 calves with the age ranging between 1-2 weeks and that presented clinical signs of colibacilosis. The samples were collected in a sterile medium for the taxonomic isolation and identification of the etiological agent involved, the ESBL screening being conducted subsequently using the ESBL Agar Oxoid Brilliance chromogenic medium. The phenotypic confirmation of the ESBL-producing strains was conducted in accordance with the CLSI (2014) standard through the combined disc method. Following the tests conducted, out of the 33 strains of isolated E. coli, 9 (27, 27%) were phenotypically confirmed as being ESBL strains.The studies that were previously conducted on the dairy farms have pointed out that the young calves rapidly acquire bacterial strains resistant to antibiotics that are often ESBL strains (Hordijk et al., 2013). The prevalence obtained by us, as well as an insufficient quantity of information concerning the antimicrobial resistance on this segment of species of animals used for the human consumption, support conducting a more thorough study, as well as the identification of ESBL resistance genes, but also of the plasmids that encode the transmission of these genes

Preliminary studies regarding antimicrobial effect of various kuwanon G – antibiotic combinations on some MRSA strains

Methicillin-resistant Staphylococcus aureus (MRSA) is a constant therapeutic challenge in humans and animals, due to the limited range of antibiotics that can be used for the management of infections. This preliminary study is based on the assessment of the antibacterial activity of kuwanon G (a prenylated flavonoid present in white mulberry, Morus alba L., Moraceae) and its interactions with various antibiotics (oxacillin, amoxicillin, erythromycin and gentamicin) against four MRSA clinical isolates (MRSA T1 – T4). The sources of all clinical isolates resistant to cefoxitin and oxacillin were infections (recurrent otitis, pyoderma and laryngopharyngitis) in dogs. Minimum inhibitory concentrations (MICs) for kuwanon G and antibiotics were determined by the microdilution method. Interactions between kuwanon G and antibiotics were evaluated by the checkerboard method and time-kill assay. MICs varied between 6.25 and 12.5μg/mL for kuwanon G alone against all four MRSA clinical isolates. According to the calculated fractional inhibitory concentration index, various combinations were synergistic and additive. Microbicidial time has confirmed the synergy as the logarithmic reductions of colony-forming units obtained for the combinations of kuwanon G and some antibiotics were 2log10 lower than the logarithmic reductions obtained for the most potent/active component of the combination. The obtained results are promising, taking into account the antibacterial activity of kuwanon G, as well as its synergistic effects with the most used antibiotics. This study reports on the antibacterial activity of kuwanon G and suggests its ability to act synergistically with antibiotics; combinations effective in combating Gram-positive including MRSA infections might be developed

Clostridium perfringens enterotoxigen involved in hemorrhagic diarrhea at dogs

Clostridium perfringens is a commensal of the human and animal intestines. The toxigenic strains of this bacterial species are responsible for some enteral diseases in humans and domestic animals. In dogs, hemorrhagic enteritis produced by Clostridium perfringens are sporadic but have a severe progression-restricted progression. In the year 2018, 9 faeces samples were taken from dewormed dogs, vaccinated but with enteritis and associated toxic conditions (vomiting, lethargy, diminished appetite) that started suddenly without any other clinical history. Based on the anamnesis, it excluded the risk of chemical poisoning. Faeces samples were subjected to the microbiological exam. The bacterioscopic examination in Gram stained smears was predominantly Gram positive bacilli with morphology and characteristic disposition for Clostridium sp and no specific morphological phenotypes for spirochetes or protozoa were identified. The samples were incubated at 37° C, under anaerobic conditions, on liquid culture media (bullion VL) and solids (Clostridium agar, SPS agar) and under aerobic conditions on culture media for aerobic bacteria (nutrient broth, blood agar) (E. coli, Salmonella sp., Shigella sp., Campylobacter sp., Yersinia sp., Serpulina sp., Vibrio sp., etc.) which can trigger enteritis in dogs. Following the bacteriological examination, strains of Clostridium sp. Biochemical tests have included the species as Clostridium perfrigens. The clinical progression in the 9 patients was different: 6 dogs responded to antibiotic therapy, recommended on the basis of the antibiotic, and 3 dogs died within 48 hours before a treatment was instituted

Necrotic enteritis in meat chicken raised at the ground in permanent bedding

Poultry necrotic enteritis is an acute clostridial infection characterized by severe necroses of intestinal mucosa. The disease begins suddenly, with a sharp increase in death rate and dehydration. Clostridium perfringens, a sporulated, anaerobic, Gram-positive bacterium is commonly found in the environment and in the gastrointestinal tract as part of the normal intestinal flora. Frequent presence in the digestive tract of healthy birds is associated with necrotic enteritis in broilers. The research was conducted on 323 samples (120 live chickens, 89 corpses, 104 feed samples and 10 water samples) collected from a farm with 32 253 hybrid Ross 308 broilers (21 days), raised at the ground on permanent bedding, where there was a significant increase in mortality above the permissible limit. The necropsy performed on 980 chicken corps revealed a different prevalence of intestinal tract lesions: bleeding wall (28.37%), mucosal necrosis (23.22%), gas content (18.57%), mucosal inflammation (15.73%) and red orange mucus in the intestines (14.10%). Bacteriological examination identified Clostridium perfringens in 11.66% of live broilers, 10.11% of chicken corps, 61.53% of feed samples and 3.09% of water samples. Increased percentage this species isolation suggests that feed taken from the hall was an important source of infection for broilers reared on the ground

The antibacterial activity and synergies between morusin and some antibiotics against MRSA strains – preliminary study

Mulberry (Morus alba L., Moraceae) is one of the most valuable and rich in phytochemicals plant. Morusin is a prenylated flavonoid present in mulberry roots and leaves. The in vitro antibacterial activity of morusin and its interactions with conventional antibiotics (oxacillin, amoxicillin and gentamicin) were evaluated against four methicillin resistant Staphylococcus aureus clinical isolates (MRSA T1 – T4) with resistance to oxacillin and cefoxitin which had been isolated from dogs with various pathologies. Minimum inhibitory concentrations (MICs) were determined by the microdilution method. The interactions were assessed by the chequerboard method - with interpretation through fractional inhibitory concentration index (FICI) and isobologram analysis. The interactions were confirmed by the time-kill assay. MICs varied between 3.125 and 6.25μg/mL for morusin alone against all four MRSA clinical isolates. Chequerboard method showed synergies for the combinations: morusin – oxacillin (FICI=0.024 - 0.27), morusin – amoxicillin (FICI=0.024 - 0.27) and morusin - gentamicin (FICI=0.05 - 0.12) against all four tested isolates. Time-kill assay determined synergies for the following combinations: morusin – oxacillin against MRSA T1, morusin – amoxicillin against MRSA T2 and morusin - gentamicin against all four isolates. Our preliminary study evaluated the antibacterial activity of morusin and its ability to act synergistically with antibiotics; these results suggest that morusin might be a promising strategy to overcome antibiotic resistence