Phage P2-71 against multi-drug resistant Proteus mirabilis: isolation, characterization, and non-antibiotic antimicrobial potential.

Proteus mirabilis, a prevalent urinary tract pathogen and formidable biofilm producer, especially in Catheter-Associated Urinary Tract Infection, has seen a worrying rise in multidrug-resistant (MDR) strains. This upsurge calls for innovative approaches in infection control, beyond traditional antibiotics. Our research introduces bacteriophage (phage) therapy as a novel non-antibiotic strategy to combat these drug-resistant infections. We isolated P2-71, a lytic phage derived from canine feces, demonstrating potent activity against MDR P. mirabilis strains. P2-71 showcases a notably brief 10-minute latent period and a significant burst size of 228 particles per infected bacterium, ensuring rapid bacterial clearance. The phage maintains stability over a broad temperature range of 30-50°C and within a pH spectrum of 4-11, highlighting its resilience in various environmental conditions. Our host range assessment solidifies its potential against diverse MDR P. mirabilis strains. Through killing curve analysis, P2-71's effectiveness was validated at various MOI levels against P. mirabilis 37, highlighting its versatility. We extended our research to examine P2-71's stability and bactericidal kinetics in artificial urine, affirming its potential for clinical application. A detailed genomic analysis reveals P2-71's complex genetic makeup, including genes essential for morphogenesis, lysis, and DNA modification, which are crucial for its therapeutic action. This study not only furthers the understanding of phage therapy as a promising non-antibiotic antimicrobial but also underscores its critical role in combating emerging MDR infections in both veterinary and public health contexts.

Virulence-related factors and antimicrobial resistance in Proteus mirabilis isolated from domestic and stray dogs.

Introduction: Proteus mirabilis is a multi-host pathogen that causes diseases of varying severity in a wide range of mammals, including humans. Proteus mirabilis is resistant to multiple antibiotics and has acquired the ability to produce expanded spectrum of ß-lactamases, leading to serious public health problems. However, the available information on P. mirabilis isolated from feces of dogs, is still poorly understood, as is the correlation between its virulence-associated genes (VAGs) and antibiotic resistance genes (ARGs). Method: In this study, we isolated 75 strains of P. mirabilis from 241 samples, and investigated the swarming motility, biofilm formation, antimicrobial resistance (AMR), distribution of VAGs and ARGs, as well as the presence of class 1, 2, and 3 integrons in these isolates. Results: Our findings suggest a high prevalence of intensive swarming motility and strong biofilm formation ability among P. mirabilis isolates. Isolates were primarily resistant to cefazolin (70.67%) and imipenem (70.67%). These isolates were found to carry ureC, FliL, ireA, zapA, ptA, hpmA, hpmB, pmfA, rsbA, mrpA, and ucaA with varying prevalence levels of 100.00, 100.00, 100.00, 98.67, 98.67, 90.67, 90.67, 90.67, 90.67, 89.33, and 70.67%, respectively. Additionally, the isolates were found to carry aac(6')-Ib, qnrD, floR, blaCTX-M, blaCTX-M-2, blaOXA-1, blaTEM, tetA, tetB and tetM with varying prevalence levels of 38.67, 32.00, 25.33, 17.33, 16.00, 10.67, 5.33, 2.67, 1.33, and 1.33%, respectively. Among 40 MDR strains, 14 (35.00%) were found to carry class 1 integrons, 12 (30.00%) strains carried class 2 integrons, while no class 3 integrons was detected. There was a significant positive correlation between the class 1 integrons and three ARGs: blaTEM, blaCTX-M, and blaCTX-M-2. This study revealed that P. mirabilis strains isolated from domestic dogs exhibited a higher prevalence of MDR, and carried fewer VAGs but more ARGs compared to those isolated from stay dogs. Furthermore, a negative correlation was observed between VAGs and ARGs. Discussion: Given the increasing antimicrobial resistance of P. mirabilis, veterinarians should adopt a prudent approach towards antibiotics administration in dogs to mitigate the emergence and dissemination of MDR strains that pose a potential threat to public health.

Validation of an HPLC assay for determination of Telazol in pregnant pigs: application to placental transfer study.

Anesthetics utilized for the immobilization of pregnant mammals are prone to crossing the placental barrier and cause adverse effects to the fetuses. In this study, we develop a facile method employing high performance liquid chromatography (HPLC) for the study of Telazol crossing the placental barrier of pregnant pigs. The method mainly relies on the efficient extraction strategy that includes the mobile phase composed of 10 mM ammonium acetate aqueous solution-acetonitrile (1:4, v/v). When the injected dose of Telazol is 10 mg/kg (5 mg/kg of each constituent drug, zolazepem and tiletamine), zolazepam can cross the placental barrier as it is detected in both uterus and umbilical cord with approximately the same content. Conversely, tiletamine is detected in neither uterus nor umbilical cord, indicating the absence of placental transfer of tiletamine. The different absorption rates of the two dosage-equal compounds by pigs are found to be the main cause of their different abilities to cross the placental barrier.

[Intestinal fungal diversity of sub-adult giant panda].

OBJECTIVE: The fungi diversity in the guts of five sub-adult giant pandas was analyzed. METHOD: We analyzed the fungal internal transcribed spacer sequences (ITS) using restriction fragment length polymorphism (RFLP). ITS regions were amplified with fungal universal primers to construct ITS clone libraries. The fingerprints were analyzed by restriction fragment length polymorphism using the Hha I and Hae III enzymes. The cloned PCR products were analyzed by sequencing and diversities were demonstrated by phylogenetic tree. RESULTS: The gut fungi of 5 sub-adult giant pandas were mainly composed of Ascomycota (average of 46.24%), Basidiomycota ( average of 15.79%), unclassified (average of 29.14%), uncultured fungus (average of 8.83% ). Ascomycota was mainly composed of Saccharomycetes (average of 63.74%) and Dothideomycetes ( average of 35.91%); Basidiomycota was mainly composed of Tremellomycetes (average of 65.80%) and Microbotryomycetes (average of 33.15%). Four classes were mainly composed of Candida and Debaryomyces; Pleosporales and Myriangium; Cystofilobasidium and Trichosporon; Leucosporidium, and Leucosporidiella, whereas the proportions were different for each sample. CONCLUSION: Fungal flora existing in the intestines of sub-adult giant pandas expand our knowledge on the structure of the giant panda gut microbes and also help us to further study whether fungal flora can help giant pandas digest high-fiber foods.