Milk Pathogens in Correlation with Inflammatory, Oxidative and Nitrosative Stress Markers in Goat Subclinical Mastitis.

Goat mastitis is still frequently diagnosed in dairy farms, with serious consequences on milk quality and composition. The aim of this study was to establish correlations between milk microorganisms and biochemical parameters in goats with no signs of clinical mastitis. Thus, 76 milk samples were collected from a dairy goat farm, Carpathian breed, followed by microbiological, molecular (16S rRNA sequencing) and somatic cells analysis, determination of lactate dehydrogenase (LDH), ß-glucuronidase, catalase (CAT), glutathione peroxidase (GPx) activity, total antioxidant capacity (TAC), nitric oxide (NO) and lipid peroxides (LPO) using spectrophotometry and the ELISA method for 8-hydroxy-deoxyguanosine (8-OHdG) as the oxidative DNA damage indicator. Samples positive for bacterial growth showed a significant (p < 0.05) increase in the number of somatic cells, LDH and ß-glucuronidase activity, as well as higher levels of CAT, GPx, NO, LPO and 8-OHdG compared with pathogen-free milk whereas TAC was lower in milk from an infected udder. These findings suggest that subclinical mastitis is associated with increased enzymatic activity and induction of oxidative stress. Nevertheless, changes in biochemical parameters tended to vary depending on the pathogen, the most notable mean values being observed overall in milk positive for Staphylococcus aureus.

In Vitro Antimicrobial Effect of Novel Electrospun Polylactic Acid/Hydroxyapatite Nanofibres Loaded with Doxycycline.

The present study aimed to assess the in vitro antimicrobial effects of a novel biomaterial containing polylactic acid (PLA), nano-hydroxyapatite (nano-HAP) and Doxycycline (Doxy) obtained by electrospinning and designed for the non-surgical periodontal treatment. The antimicrobial activity of two samples (test sample, PLA-HAP-Doxy7: 5% PLA, nano-HAP, 7% Doxy and control sample, PLA-HAP: 5% PLA, nano-HAP) against two periodontal pathogens­Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis­was assessed using the Kirby−Bauer Disk Diffusion Susceptibility Test and compared with the effect of four antibiotics used as adjuvants in periodontal therapy: Amoxicillin, Ampicillin, Doxy and Metronidazole. The test sample (embedded with Doxy) showed higher inhibitory effects than commonly used antibiotics used in the treatment of periodontitis, while the control sample showed no inhibitory effects. Moreover, significant differences were observed between the inhibition zones of the two samples (p < 0.05). The Doxy-loaded PLA nanofibres had an antimicrobial effect against the periodontal pathogens. Based on these results, the novel biomaterial could be a promising candidate as adjuvant for the non-surgical local treatment in periodontitis.

Prevalence of Antimicrobial Resistant Bacteria from Conjunctival Flora in an Eye Infection Prone Breed (Saint Bernard).

The conjunctival bacterial resident and opportunistic flora of dogs may represent a major source of dissemination of pathogens throughout the environment or to other animals and humans. Nevertheless, contamination with bacteria from external sources is common. In this context, the study of the antimicrobial resistance (AMR) pattern may represent an indicator of multidrug resistant (MDR) strains exchange. The present study was focused on a single predisposed breed-Saint Bernard. The evaluated animals were healthy, but about half had a history of ocular disease/treatment. The swabs collected from conjunctival sacs were evaluated by conventional microbiological cultivation and antimicrobial susceptibility testing (AST). The most prevalent Gram-positive was Staphylococcus spp.; regardless of the history, while Gram-negative was Pseudomonas spp.; exclusively from dogs with a history of ocular disease/treatment. Other identified genera were represented by Bacillus, Streptococcus, Trueperella, Aeromonas and Neisseria. The obtained results suggest a possible association between the presence of mixed flora and a history of ocular disease/treatment. A high AMR was generally observed (90%) in all isolates, especially for kanamycin, doxycycline, chloramphenicol and penicillin. MDR was recorded in Staphylococcus spp. and Pseudomonas spp. This result together with a well-known zoonotic potential may suggest an exchange of these strains within animal human populations and the environment.

In Vitro Antibacterial Susceptibility of Different Pathogens to Thirty Nano-Polyoxometalates.

Due to their unique properties, nano-polyoxometalates (POMs) can be alternative chemotherapeutic agents instrumental in designing new antibiotics. In this research, we synthesized and characterized "smart" nanocompounds and validated their antibacterial effects in order to formulate and implement potential new drugs. We characterized thirty POMs in terms of antibacterial activity-structure relationship. The antibacterial effects of these compounds are directly dependent upon their structure and the type of bacterial strain tested. We identified three POMs that presented sound antibacterial activity against S. aureus, B. cereus, E. coli, S. enteritidis and P. aeruginosa strains. A newly synthesized compound K6[(VO)SiMo2W9O39]·11H2O (POM 7) presented antibacterial activity only against S. aureus (ATCC 6538P). Twelve POMs exerted antibacterial effects against both Gram-positive and Gram-negative strains. Only one POM (a cluster derivatized with organometallic fragments) exhibited a stronger effect compared to amoxicillin. New studies in terms of selectivity and specificity are required to clarify these extremely important aspects needed to be considered in drug design.