Luteolin increases susceptibility to macrolides by inhibiting MsrA efflux pump in Trueperella pyogenes

Trueperella pyogenes (T. pyogenes) is an opportunistic pathogen associated with a variety of diseases in many domestic animals. Therapeutic treatment options for T. pyogenes infections are becoming limited due to antimicrobial resistance, in which efflux pumps play an important role. This study aims to evaluate the inhibitory activity of luteolin, a natural flavonoid, on the MsrA efflux pump and investigate its mechanism. The results of antimicrobial susceptibility testing indicated that the susceptibility of msrA-positive T. pyogenes isolates to six macrolides increased after luteolin treatment, while the susceptibility of msrA-negative isolates showed no change after luteolin treatment. It is suspected that luteolin may increase the susceptibility of T. pyogenes isolates by inhibiting MsrA activity. After 1/2 MIC luteolin treatment for 36 h, the transcription level of the msrA gene and the expression level of the MsrA protein decreased by 55.0–97.7% and 36.5–71.5%, respectively. The results of an affinity test showed that the equilibrium dissociation constant (KD) of luteolin and MsrA was 6.462 × 10–5 M, and hydrogen bonding was predominant in the interaction of luteolin and MsrA. Luteolin may inhibit the ATPase activity of the MsrA protein, resulting in its lack of an energy source. The current study illustrates the effect of luteolin on MsrA in T. pyogenes isolates and provides insight into the development of luteolin as an innovative agent in combating infections caused by antimicrobial-resistant bacteria.

Monitoring of bacterial agents isolated from small cattle on the territory of certain regions of the Russian Federation

The paper presents the results of bacterial screening of goat and sheep breeding enterprises in certain regions of Russia (Tver, Moscow, Smolensk regions, as well as the Republic of Mari-El and Tatarstan), conducted in the period from 2018 to 2021. In the course of this work, 556 samples of sectional material (heart, lungs, gastrointestinal tract, spleen, kidneys, liver, lymph nodes, breast, flushes from the genitourinary system, as well as exudate from purulent lesions) were subjected to a comprehensive bacteriological study. As a result of the conducted studies, 1223 isolates belonging to 25 families (111 bacterial species) were isolated and identified (by the method of time-of-flight mass spectrometry MALDI-ToF). According to the data obtained, the incidence of Escherichia coli isolation was 10.95%, Trueperella pyogenes – 5.47%, Staphylococcus aureus – 5.31%, Proteus mirabilis – 4.08%, Mannheimia haemolytica – 4.00%, Enterococcus faecalis – 3.76%, Enterobacter cloacea and Staphylococcus haemolyticus – 3.59%, Streptococcus dysgalactiae – 3.51%, Pasteurella multocida – 3.27%, Acinetobacter lwoffii – 2.78%, Staphylococcus cohnii – 2.61%, Bibersteinia trehalosi – 2.29%, Pseudomonas aeruginosa – 2.12%, Bacillus cereus and Micrococcus luteus – 1.96%, Corynebacterium pseudotuberculosis and Staphylococcus equorum – 1.88%, Aerococcus viridans – 1.80%, Corynebacterium xerosis – 1.72%, Clostridium perfringens, Streptococcus mitis and Streptococcus pyogenes – 1.39%, Staphylococcus chromogenes and Streptococcus entericus – 1.14%, respectively. The incidence of isolation of other types of microorganisms was below 1%. The data obtained indicate the circulation of a wide range of bacteria in goat and sheep breeding enterprises of the Russian Federation, some of which should be positioned as pathogenic flora (for example, Pasteurella multocida, Listeria monocytogenes, Salmonella enteritidis, Salmonella typhimurium, Clostridium perfringens, etc.), some as conditionally pathogenic (Trueperella pyogenes, Staphylococcus aureus, Bibersteinia trehalosi, Mannheimia haemolytica, Pseudomonas aeruginosa, Moraxella bovis, Moraxella bovoculi, etc.), as well as the normal flora of the animal body. It is worth focusing on these data when conducting a survey of livestock enterprises in order to establish an objective epizootic situation, including taking into account the possibility of circulating pathogens of factor diseases.

Suppurative meningoencephalitis secondary to a Trueperella pyogenes-induced mandibular abscess in a free-ranging gray brocket deer (Mazama gouazoubira)

Trueperella pyogenes is an opportunistic pathogen, most commonly affecting ruminants and pigs. A female free-ranging gray brocket deer (Mazama gouazoubira) had an abscess in the masseter muscle associated with an osteolysis and osteomyelitis in the adjacent right mandibule, with a fistulous tract to the orbit and through the optic foramen into the skull, causing a suppurative meningitis. Histologically, the abscess was characterized by a neutrophilic and histiocytic inflammatory infiltrate with myriad of Gram-positive rod-shaped bacteria, and a focally extensive suppurative and histiocytic leptomeningitis of the ventral portions of the brain. Aerobic microbiologic culture, MALDI-ToF, and PCR identified T. pyogenes.

TatD DNases Contribute to Biofilm Formation and Virulence in Trueperella pyogenes

TatD DNases are conserved proteins in a variety of organisms and are considered potential virulence factors in Plasmodium falciparum and Streptococcus pneumoniae. However, the function of TatD DNases has not yet been determined in Trueperella pyogenes, which causes various infections in animals and leads to economic losses. In this study, we describe the roles of TatD DNases in T. pyogenes (TpTatDs). A bioinformatics analysis was performed to investigate the sequence characteristics of TpTatDs, and then the ability of recombinant TatD proteins to hydrolyze DNA was determined in the presence of divalent cations. Moreover, we constructed tatD-deficient mutants. The biofilms formed by the wild-type and mutant strains were observed under a microscope. The mortality and bacterial load in the spleen of mice infected with the wild-type strain and tatD-deficient mutants were determined to obtain insights into the role of TatDs in the virulence of T. pyogenes. Two TatD DNases were identified in T. pyogenes. They were Mg2+-dependent DNases and exhibited DNA endonuclease activity. Compared with those formed by the parental strain, biofilms formed by mutants showed a significantly reduced thickness and biomass. Moreover, mutants produced a lower bacterial load in the spleen of mice and compromised virulence. Our data indicated that TatD DNases in T. pyogenes are involved in biofilm formation and required for virulence during infections.

Helcococcus ovis bei septischer Arthritis und Bursitis bei Kälbern

Septische Arthritiden und Pneumonien gehören bei Mastkälbern zu den häufigsten Todesursachen. Septische Arthritiden oder Entzündungen der synovialen Einrichtungen haben v. a. traumatische Ursachen, entstehen durch periartikuläre Entzündungsprozesse oder infolge einer hämatogenen Erregerstreuung. Die in diesem Zusammenhang beim Rind gewöhnlich nachweisbaren Erreger sind Trueperella pyogenes, Streptococcus spp., Staphylococcus spp. und E. coli. Eine mögliche hämatogene Streuung bei bestehender Bronchopneumonie ist bekannt und oft mit dem Nachweis von Mycoplasma spp. assoziiert. In letzter Zeit häufen sich jedoch Berichte über die Beteiligung von Helcococcus ovis als neu aufkommendem Pathogen, meist in Form von Koinfektionen mit anderen Bakterien. In diesem Fallbericht wird eine Monoinfektion mit Helcococcus ovis bei Kälbern einer Milchviehherde dargestellt.

Complete genome sequence of Trueperella pyogenes strain Arash114, isolated from the uterus of a water buffalo (Bubalus bubalis) in Iran

Objective Trueperella pyogenes has been considered a major causative agent of metritis, abortion, and death in a broad range of domestic and wild animals, including cattle, swine, sheep, goats, camels, buffalo, deer, antelopes, reptiles, and birds. Data description Here, we report the complete chromosome sequence of Trueperella pyogenes strain Arash114, isolated from the uterus of a water buffalo (Bubalus bubalis) died due to the infection caused by this pathogen. The genome assembly comprised 2,338,282 bp, with a 59.5% GC content. Annotation of the genome showed 46 tRNA genes, 6 rRNA, 1 CRISPR and 2059 coding sequences. Also, several genes coding for antimicrobial resistance such as tetW and virulence factor including plo, nanH, nanP, cbp and 4 fimbrial proteins were found. This study will advance our knowledge regarding the metabolism, virulence factors, antibiotic resistance and evolution of Arash114 strain and serve as an appropriate template for future researches.

Antibacterial and Anti-Virulence Effects of Furazolidone on Trueperella Pyogenes and Pseudomonas Aeruginosa

Background: Trueperella pyogenes and Pseudomonas aeruginosa are two important bacterial pathogens closely relating to the occurrence and development of forest musk deer respiratory purulent disease. Although T. pyogenes is the causative agent of the disease, the subsequently invaded P. aeruginosa will predominate the infection by producing a substantial amount of quorum-sensing (QS)-controlled virulence factors, and co-infection of them usually creates serious difficulties for veterinary treatment. In order to find a potential drug that targets both T. pyogenes and P. aeruginosa, the antibacterial and anti-virulence capacities of 55 compounds, which have similar core structure to the signal molecules of P. aeruginosa QS system, were tested in this study. By performing a series of in vitro screening experiments to assess the effects of these compounds.Results: We identified that furazolidone could significantly inhibit the growth of mono-cultured T. pyogenes or in the co-culture with P. aeruginosa. Although the growth of P. aeruginosa could also be moderately inhibited by furazolidone, the results of phenotypic identification and transcriptomic analysis further revealed that furazolidone had remarkable inhibitory effect on the biofilm production, motility, and QS system of P. aeruginosa. Moreover, furazolidone could efficiently protect Caenorhabditis elegans from P. aeruginosa infection under both fast-killing and slow-killing conditions.Conclusions: This study reports the antibacterial and anti-virulence abilities of furazolidone on T. pyogenes and P. aeruginosa, and provides a promising strategy and molecular basis for the development of novel anti-infectious drugs to dealing with forest musk deer purulent disease, or other diseases caused by T. pyogenes and P. aeruginosa co-infection.

Antimicrobial Resistance and Virulence Genes Distribution in Trueperella pyogenes Isolated from Dairy Cows with Clinical Mastitis in Liaoning of China

Trueperella pyogenes is considered as a causative agent of many infections, such as mastitis, endometritis, pneumonia, liver abscessation. T. pyogenes can express several virulence genes such as plo, fimA, cbpA, nanH and nanP contributing to its pathogenicity. The aim of this study was to provide an investigation about antimicrobial resistance, as well as virulence genes distribution and gene cassettes among T. pyogenes isolates from dairy cows with clinical mastitis. The susceptibility to different antimicrobial agents was determined by the Broth Microdilution Method, and virulence genes and gene cassette was detected by polymerase chain reactions (PCRs). There are 10.49% (17/162) of milk samples from dairy cows with mastitis were positive for T. pyogenes. High levels of resistance were found to clindamycin (23.53%), oxytetracycline (23.53%), ciprofloxacin (47.06%), sulfamethoxazole/trimethoprim (100%). Moreover, all isolates carried class I integrons, and gene cassette arrays were aadA9 (2/17) or aadA5-dfrA17 (3/17). Finally, all isolates harbored plo nanH and fimA genes, but other genes encoding virulence genes including fimC, fimE, nanP and cbpA are ranged from 47.06% to 88.23%. Our study showed T. pyogenes isolates from dairy cows with clinical mastitis were susceptible to β-lactams. In addition, all seven virulence genes occurred in isolates, and plo, nanH, and fimA gene showed a significantly higher frequency in T. pyogenes of the Liaoning Province, China.