Antimicrobial efficiency of bromhexine hydrochloride against endometritis-causing Escherichia coli and Trueperella pyogenes in bovines.

In this study, the main agents associated with endometritis in cows in the state of Santa Catarina, Brazil, were identified and the resistance profile and virulence mechanisms of the bacterial isolates were evaluated. Isolates of Escherichia coli and Trueperella pyogenes were tested for their biofilm forming ability and the antimicrobial action of bromhexine hydrochloride in combination with other antimicrobials. A total of 37 uterine lavage samples were collected from cows with endometritis. Of the 55 bacteria isolated, 25.4% were identified as T. pyogenes and 16.3% as E. coli. The bacterial isolates showed greater resistance to sulfamethoxazole + trimethoprim (58.2%) and tetracycline (56.3%). Among the species, E. coli showed the highest resistance rates, with 100% of isolates showing resistance to amoxicillin, streptomycin, and gentamicin. The results of the minimum inhibitory concentration for the T. pyogenes isolates showed that 91.6% of the isolates were resistant to enrofloxacin and tetracycline, and 75% were resistant to ceftiofur and sulfamethoxazole + trimethoprim. All E. coli and T. pyogenes isolates showed biofilm forming ability. The plo, fimA, and nanH genes were identified in 100% of T. pyogenes isolates. In parallel, 100% of E. coli isolates had the fimH gene, and 11.1% had the csgD gene. Bromhexine hydrochloride showed antimicrobial activity against 100% of E. coli isolates and 66.6% of T. pyogenes isolates. Furthermore, when associated with antimicrobials, bromhexine hydrochloride has a synergistic and additive effect, proving to be an option in the treatment of endometritis in cows and an alternative for reducing the use of antimicrobials.

Multiphasic investigations imply transfer of orange-/red-pigmented strains of the bean pathogen Curtobacterium flaccumfaciens pv. flaccumfaciens to a new species as C. aurantiacum sp. nov., elevation of the poinsettia pathogen C. flaccumfaciens pv. poinsettiae to the species level as C. Poinsettiae sp. nov., and synonymy of C. albidum with C. citreum.

Curtobacterium flaccumfaciens (Microbacteriaceae), a plant-pathogenic coryneform species includes five pathovars with valid names and a number of proposed - but unvalidated - new members. In this study, phenotypic features and DNA similarity indexes were investigated among all C. flaccumfaciens members. Results showed that the C. flaccumfaciens pv. poinsettiae strains causing bacterial canker of Euphorbia pulcherrima in the USA as well as the orange-/red-pigmented strains of C. flaccumfaciens pv. flaccumfaciens pathogenic on dry beans in Iran are too distinct from each other and from the type strain of the species to be considered members of C. flaccumfaciens. Hence, the latter two groups were elevated at the species level as C. poinsettiae sp. nov. (ATCC 9682T = CFBP 2403T = ICMP 2566T = LMG 3715T = NCPPB 854T as type strain), and C. aurantiacum sp. nov. (50RT = CFBP 8819T = ICMP 22071T as type strain). Within the emended species C. flaccumfaciens comb. nov., yellow-pigmented strains causing bacterial wilt of dry beans and those causing bacterial canker of Euphorbia pulcherrima in Europe were retained as C. flaccumfaciens pv. flaccumfaciens and C. flaccumfaciens pv. poinsettiae, respectively; while taxonomic position of the sugar beet pathogen C. flaccumfaciens pv. beticola ATCC BAA144PT was confirmed. The newly described onion pathogen C. allii was also reclassified as C. flaccumfaciens pv. allii with the pathotype strain LMG 32517PT. Furthermore, C. flaccumfaciens pv. basellae causing bacterial leaf spot of malabar spinach (Basella rubra) was transferred to C. citreum pv. basellae with ATCC BAA143PT as pathotype.

Analysis of Urinary Flora Characteristics in Urinary Tumor Based on 16S rRNA Sequence.

The relationship between urinary system tumors and urothelial microorganisms remains unexplored. This study is aimed at exploring the relationship between urinary flora and urinary tumors and identifying potential biomarkers for urinary tumors and new targets for prevention. We included four healthy adults (control group) and six patients diagnosed with urinary tract tumors (tumor group). In both groups, 10 and 50 ml clean middle urine samples were reserved. The 10 ml samples were analyzed (including pH, specific gravity, and leukocytes) using an automatic urine analyzer, and the 50 ml samples were analyzed by DNA extraction, 16S rRNA gene amplification, and high-throughput sequencing. The correlation between routine urine analysis and sequencing results was also analyzed. Testing using the DESeq2 method showed that, at the order level, there were significant differences in the abundance of Caulobacterales between the urinary flora of the two groups (P < 0.05); family level, Bacteroidaceae, Actinomycetaceae, and Tsukamurellaceae (P < 0.05); genus level, Finegoldia, Varibaculum, Actinobaculum, Propionimicrobium, Bacteroides, Brevundimonas, and Tsukamurella (P < 0.05). LEfSe analysis found specific bacteria at the genus level in the urinary flora of the tumor group, namely, Finegoldia (genus Digestiflora) (P < 0.001) and Varibaculum (P < 0.001). Further correlation analysis showed that both species were positively correlated with the urine pH (P < 0.05). PICRUSt analysis showed significant differences in the two functional pathways of cell transformation and metabolism (P < 0.05). Combined with the results of bioinformatics analysis, some differential bacteria may be new biomarkers for urologic tumors, and there may be a correlation between urine pH and tumor occurrence. However, large-scale prospective studies and in vitro and in vivo experiments are required to further test and verify these findings.

Expression of virulence factor genes in co-infections with Trueperella pyogenes isolates and other bacterial pathogens; an in vivo study.

Trueperella pyogenes is an opportunistic bacterial pathogen causing several infectious diseases, including metritis, mastitis and abscesses in domestic animals such as dairy cattle. Several virulence proteins are released by T. pyogenes strains contributing to the pathogenic and causing disease potential of this pathogen. So far, many aspects of T. pyogenes pathogenesis are unknown. In this study, expression levels of plo, fimA, nanH and cbpA genes encoding pyolysin, fimbriae, neuraminidase and collagen-binding protein, respectively in T. pyogenes isolated from totally 15 metritis, mastitis and cutaneous abscesses convenience samples in response to co-culture with other pathogens including E. coli, St. dysgalactiae, S. aureus, F. necrophorum and L. plantarum strains in mice study model have been investigated. We found that expression levels of plo, fimA, nanH and cbpA genes in T. pyogenes isolates in response to co-culture with F. necrophorum and E. coli were significantly increased; however, no significant changes was seen in the level of expression of these genes in the isolates in response to co-culture with St. dysgalactiae and S. aureus. Notably, expression of all virulence factor genes was suppressed in T. pyogenes in response to co-culture with L. plantarum. We observed that L. plantarum might be used to prevent infectious diseases caused by T. pyogenes.

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.

Actinomycosis in a gray four-eyed opossum (Philander opossum) caused by a novel species of Schaalia.

BACKGROUND: Infective lesions of the jaws and adjacent tissues (lumpy jaw disease, LJD) have been recognized as one major cause of death of captive macropods. Fusobacterium necrophorum and Actinomyces species serve as the main source of LJD in kangaroos and wallabies. Currently, little is reported about LJD or similar diseases in opossums. CASE PRESENTATION: Here we report a case of actinomycosis resembling the entity lumpy jaw disease in a gray four-eyed opossum, caused by a novel species of Schaalia. A 2.8 year old male Philander opossum was presented with unilateral swelling of the right mandible. After an initial treatment with marbofloxacin, the opossum was found dead the following day and the carcass was submitted for necropsy. Postmortem examination revealed severe mandibular skin and underlying soft tissue infection with subsequent septicemia as the cause of death. Histological examination demonstrated Splendore-Hoeppli phenomenon, typically seen in classical cases of actinomycosis. Bacteriology of liver and mandibular mass yielded a previously undescribed species of Schaalia, whose 16 S rRNA gene sequence was 97.0 % identical to Schaalia canis. Whole genome sequencing of the opossum isolate and calculation of average nucleotide identity confirmed a novel species of Schaalia, for which no whole genome sequence is yet available. CONCLUSIONS: The herewith reported Schaalia infection in the gray four-eyed opossum resembling classical actinomycosis gives a novel insight into new exotic animal bacterial diseases. Schaalia species may belong to the normal oral microbiome, as in macropods, and may serve as a contributor to opportunistic infections. Due to the lack of current literature, more insights and improved knowledge about Schaalia spp. and their pathogenicity will be useful to choose appropriate therapy regimens and improve the treatment success rate and outcome in exotic and endangered species.

Septic hip abscess due to Fusobacterium nucleatum and Actinomyces turicensis in an immunocompetent SARS-CoV-2 positive patient.

A 42-year-old man was referred to the Department of Orthopedic Surgery with pain over his right greater trochanter and signs of systemic infection. CT showed an enhanced mass in his gluteus maximus as well as gas in the biceps femoris over the underlying hip joint. Tissue biopsy yielded Fusobacterium nucleatum and Actinomyces turicensis. The patient was successfully treated for 6 weeks with amoxicillin/clavulanic acid 875mg/125mg and metronidazole 500mg.

Adapted Protocol for Saccharibacteria Cocultivation: Two New Members Join the Club of Candidate Phyla Radiation.

The growing application of metagenomics to different ecological and microbiome niches in recent years has enhanced our knowledge of global microbial biodiversity. Among these abundant and widespread microbes, the candidate phyla radiation (CPR) group has been recognized as representing a large proportion of the microbial kingdom (>26%). CPR are characterized by their obligate symbiotic or exoparasitic activity with other microbial hosts, mainly bacteria. Currently, isolating CPR is still considered challenging for microbiologists. The idea of this study was to develop an adapted protocol for the coculture of CPR with a suitable bacterial host. Based on various sputum samples, we tried to enrich CPR (Saccharibacteria members) and to cocultivate them with pure hosts (Schaalia odontolytica). This protocol was monitored by TaqMan real-time quantitative PCR (qPCR) using a system specific for Saccharibacteria designed in this study, as well as by electron microscopy and sequencing. We succeeded in coculturing and sequencing the complete genomes of two new Saccharibacteria species, "Candidatus Minimicrobia naudis" and "Candidatus Minimicrobia vallesae." In addition, we noticed a decrease in the CT values of Saccharibacteria and a significant multiplication through their physical association with Schaalia odontolytica strains in the enriched medium that we developed. This work may help bridge gaps in the genomic database by providing new CPR members, and in the future, their currently unknown characteristics may be revealed. IMPORTANCE In this study, the first TaqMan real-time quantitative PCR (qPCR) system, targeting Saccharibacteria phylum, has been developed. This technique can specifically quantify Saccharibacteria members in any sample of interest in order to investigate their prevalence. In addition, another easy, specific, and sensitive protocol has been developed to maintain the viability of Saccharibacteria cells in an enriched medium with their bacterial host. The use of this protocol facilitates subsequent studies of the phenotypic characteristics of CPR and their physical interactions with bacterial species, as well as the sequencing of new genomes to improve the current database.

Studies on Trueperella pyogenes isolated from an okapi (Okapia johnstoni) and a royal python (Python regius).

BACKGROUND: The present study was designed to characterize phenotypically and genotypically two Trueperella pyogenes strains isolated from an okapi (Okapia johnstoni) and a royal python (Python regius). CASE PRESENTATION: The species identity could be confirmed by phenotypic properties, by MALDI-TOF MS analysis and by detection of T. pyogenes chaperonin-encoding gene cpn60 with a previously developed loop-mediated isothermal amplification (LAMP) assay. Furthermore, sequencing of the 16S ribosomal RNA (rRNA) gene, the 16S-23S rDNA intergenic spacer region (ISR), the target genes rpoB encoding the ß-subunit of bacterial RNA polymerase, tuf encoding elongation factor tu and plo encoding the putative virulence factor pyolysin allowed the identification of both T. pyogenes isolates at species level. CONCLUSIONS: Both strains could be clearly identified as T. pyogenes. The T. pyogenes strain isolated in high number from the vaginal discharge of an okapi seems to be of importance for the infectious process; the T. pyogenes strain from the royal python could be isolated from an apparently non-infectious process. However, both strains represent the first isolation of T. pyogenes from these animal species.

New Determinants of Aminoglycoside Resistance and Their Association with the Class 1 Integron Gene Cassettes in Trueperella pyogenes.

Trueperella pyogenes is an important opportunistic animal pathogen. Different antimicrobials, including aminoglycosides, are used to treat T. pyogenes infections. The aim of the present study was to evaluate aminoglycoside susceptibility and to detect aminoglycoside resistance determinants in 86 T. pyogenes isolates of different origin. Minimum inhibitory concentration of gentamicin, streptomycin, and kanamycin was determined using a standard broth microdilution method. Genetic elements associated with aminoglycoside resistance were investigated by PCR and DNA sequencing. All studied isolates were susceptible to gentamicin, but 32.6% and 11.6% of them were classified as resistant to streptomycin and kanamycin, respectively. A total of 30 (34.9%) isolates contained class 1 integrons. Class 1 integron gene cassettes carrying aminoglycoside resistance genes, aadA11 and aadA9, were found in seven and two isolates, respectively. Additionally, the aadA9 gene found in six isolates was not associated with mobile genetic elements. Moreover, other, not carried by gene cassettes, aminoglycoside resistance genes, strA-strB and aph(3')-IIIa, were also detected. Most importantly, this is the first description of all reported genes in T. pyogenes. Nevertheless, the relevance of the resistance phenotype to genotype was not perfectly matched in 14 isolates. Therefore, further investigations are needed to fully explain aminoglycoside resistance mechanisms in T. pyogenes.

Differences in phenotypic and genetic characteristics of Trueperella pyogenes detected in slaughtered cattle and pigs with septicemia.

We investigated the hemolytic properties, biochemical properties, and possession of virulence factor genes of Trueperella pyogenes isolated from cattle and pigs with septicemia. The porcine strains showed significantly stronger hemolyticity than the bovine strains. In addition, T. pyogenes from cattle and pigs also differed in biochemical properties. Virulence factor genes (nanP, cbpA, fimC, and fimE) were more prevalent in bovine strains, whereas other virulence factor genes (nanH and fimG) were more prevalent in porcine strains. T. pyogenes isolated from pig and cattle with septis cases in Japanese meat inspection showed variability in biochemical and genetic properties. Differences were observed between porcine and bovine strain in term of the hemolytic strength and possession of genes for factors promoting adhesions which are considered pathogenic.

Genomic island type IV secretion system and transposons in genomic islands involved in antimicrobial resistance in Trueperella pyogenes.

Trueperella pyogenes (T. pyogenes) is a well-known opportunistic pathogen of many animal species. It can cause a variety of suppurative infections. The objective of this research was to get insight into the gene context and the location of the antimicrobial resistance determinants in the two multi-resistant T. pyogenes isolates TP3 and TP4. Comparative analysis of key factors leading to antimicrobial resistance was performed. Both isolates were resistant to erythromycin, azithromycin and tetracycline, and susceptible to ciprofloxacin, enrofloxacin, cefazolin and florfenicol. In addition, TP4 was resistant to amikacin and gentamicin. Whole-genome analyses revealed that both TP3 and TP4 contained two different genomic islands (TP3-GI1, TP3-GI5, TP4-GI5 and TP4-GI8) involved in multi-drug resistance. There is a common region in TP3-GI1 and TP4-GI5, containing the tetracycline resistance gene tet(W) and a series of genes involved in type IV secretion systems. Several genes located on TP3-GI5 and TP4-GI8 are highly homologous. Tetracycline-resistance gene tet(33) was potentially acquired by horizontal gene transfer via IS6100 located on 57,936 bp TP3-GI5. The macrolide resistance gene erm(X) was located near the end of the TP3-GI5. The sequence analysis of TP4-GI8 showed that two copies of erm(X) and two IS1634 elements located in the same orientation may have formed a composite transposon. GI-type T4SS, transposons and multiple resistance genes located on GIs play a key role in multiple drug resistance of TP3 and TP4.

Development of a novel Trueperella pyogenes-specific PCR assay.

Trueperella pyogenes is an opportunistic pathogen that causes a wide variety of purulent infections. We recently isolated a T. pyogenes strain unable to be identified by the previously reported T. pyogenes pyolysin gene (plo)-specific PCR from the lung of a sheep with astasia. Sequence comparison of plo among representative strains revealed several nucleotide substitutions in the primer-annealing regions. As such substitutions were considered to be a reason for the low PCR specificity, we designed novel primers in conserved regions of plo. Under optimized conditions, the novel primers precisely identified all T. pyogenes strains tested, and no products were generated from any other bacterial strains, suggesting the usefulness of the novel PCR assay for the diagnosis of T. pyogenes infections.

Multidrug resistance genes are associated with a 42-kb island TGI1 carrying a complex class 1 integron in Trueperella pyogenes.

OBJECTIVES: This research was conducted to ascertain the context and location of the antibiotic resistance determinants in a multiple antibiotic-resistant Trueperella pyogenes isolate TP1. METHODS: The genome was sequenced using PacBio RS II, and the filtered data were assembled using Canu. Sequences were annotated on the basis of those in GenBank, and the genomic island (GI) of the TP1 was predicted by IslandPath-DIMOB. RESULTS: TP1 as a multiple antibiotic-resistant isolate was recovered at Jilin Province (China) in 2017 from a dairy cow with pneumonia. TP1 exhibited resistance to aminoglycosides (gentamicin and amikacin), macrolides (erythromycin), lincosamides (clindamycin), sulfonamides (sulfamonomethoxine), tetracyclines (tetracycline and doxycycline) and chloramphenicols (chloramphenicol and florfenicol). An antibiotic resistance gene clustered together with the aadB, aadA1, cmlA5 and cmlA6 resistance genes located on a 7-kilobase (kb) multidrug-resistant (MDR) region, constituting a complex class 1 integron. The MDR region was located at one end of a 42-kb GI, and IS6100Δ1 mediated a genetic rearrangement with the complex class 1 integron-like SGI1 and formed a composite transposon. Furthermore, the tetW gene was located outside the four GIs consistent with tetracycline and doxycycline resistance. The ermD gene positioned in the front end of the 42-kb GI played an important role in mediating acquired erythromycin and clindamycin resistance. CONCLUSIONS: Multiple resistance genes are located in a complex class 1 integron within a 42-kb T. pyogenes genomic island (TGI1), leading to TP1 multiple drug resistance. In comparison with SG1 families, TGI1 possesses versatile gene distribution and specific gene context for it upstream and downstream, and it represents a new lineage of genomic resistance islands.

Antimicrobial susceptibility and genetic characterization of Trueperella pyogenes isolates from pigs reared under intensive and extensive farming practices.

Trueperella pyogenes is an opportunistic pathogen associated with a variety of diseases and responsible for important economic losses for pig production. Minimal Inhibitory Concentration (MIC) and Pulsed Field Gel Electrophoresis (PFGE) typing analysis were used to determine the MIC distribution and to genetically characterize a total of 180 T. pyogenes isolates obtained from slaughtered pigs reared under intensive (TpIN, n = 89) and extensive (TpEX, n = 91) farming practices. Low MIC90 values for penicillin and amoxicillin (0.008 and 0.06 µg/ml, respectively), ceftiofur, gentamicin and enrofloxacin (1 µg/ml, respectively) were obtained, so they could be of choice for the empiric treatment of T. pyogenes infections. Except for the penicillin, amoxicillin and ceftiofur, a statistically significant difference was observed in the MIC distribution of all antimicrobials analysed between TpIN and TpEX isolates. Also, MIC90 values were higher in TpIN than in TpEX isolates for neomycin and streptomycin (32 µg/ml vs 8 µg/ml), sulfamethoxazole/trimethoprim (30.4/1.6 µg/ml vs 1.90/0.10 µg/ml) and tylosin (≥1024 µg/ml vs 1 µg/ml). A relatively lower genetic diversity was detected in TpIN in comparison with TpEX isolates (GD 0.42 and GD 0.47, respectively). All isolates were distributed in three clusters (A, B, C). TpIN isolates were statistically associated with cluster A (P = 0.0002; OR 3.21; CI95 1.74-5.93), whereas the TpEX were distributed throughout the dendrogram, showing more genetic diversity. These data suggest that the antimicrobial susceptibility and genetic variability of the T. pyogenes isolates could be influenced by the management systems.

Phenotypic, molecular and genomic characterization of Actinobaculum suis isolated from swine in Brazil.

Urinary tract infections (UTI) are considered one of the most important diseases of sows due to its close relationship with reproductive problems such as reduced litter size, increase in the rate of return to estrous, vulvar discharge, abortion, mastitis and anestrus. Actinobaculum suis is one of the main agents involved in porcine urinary tract infection and is responsible for the most severe and fatal cases in sows. In the present report, 23 A. suis strains isolated from a sow and boars in Brazil were identified by PCR and further characterized by broth microdilution, molecular typing by pulsed-field gel electrophoresis (PFGE), single-enzyme amplified fragment length polymorphism (SE-AFLP), and whole-genome sequencing. All strains were sensitive to ceftiofur, linezolid, nitrofurantoin, quinupristin-dalfopristin and vancomycin. Ciprofloxacin, daptomycin, lincomycin, erythromycin and tylosin resistance was observed in 100% of tested strains. Tetracycline and tigecycline also presented high resistance rates (87% and 30.4%, respectively). PFGE with eight different restriction enzymes and three programs did not enable strain characterization; however, all strains were typed by SE-AFLP that clustered strains according to their origin, thus proving an effective tool for A. suis genotyping. Whole-genome sequencing and comparative analysis enabled species differentiation from closely related genus. This is the first report of genomic characterization of A. suis.

Luteolin Showed a Resistance Elimination Effect on Gentamicin by Decreasing MATE mRNA Expression in Trueperella pyogenes.

Trueperella pyogenes is a common inhabitant of mucosal surfaces in animals and causes a variety of infections, including endometritis, mastitis, and liver abscessation, in dairy cows. Many antimicrobial agents are used for treatment of infections caused by T. pyogenes; however, antibiotic resistance has recently become a serious problem. The objective of this study was to characterize the effect of the efflux pump-encoding multidrug and toxic compound extrusion (MATE) gene on antibiotic resistance in T. pyogenes isolates from cows with signs of endometritis. As a compound from plants, luteolin showed antimicrobial activities in Escherichia coli and Staphylococcus aureus; therefore, we also investigated whether luteolin can eliminate antibiotic resistance. We constructed a MATE deletion mutant in BM-H06-3 to identify the function of MATE in antibiotic resistance. MATE mRNA expression was measured to identify the mechanism of luteolin in gentamicin resistance elimination effect in T. pyogenes. The T. pyogenes isolate BM-H06-3 became susceptible to gentamicin, amikacin, streptomycin, erythromycin, and roxithromycin after MATE deletion. No synergistic effect between luteolin and gentamicin was observed in eight isolates, which were randomly selected from 34 T. pyogenes isolates, but the isolates became susceptible to gentamicin after luteolin treatment at a subinhibitory concentration (1/4 minimum inhibitory concentration [MIC]) for 36 hr. Furthermore, luteolin can decrease MATE mRNA expression after luteolin treatment at a subinhibitory concentration (1/4 MIC). We found that the MATE gene was involved in antibiotic resistance and that luteolin induces a resistance elimination effect in T. pyogenes. Therefore, luteolin may be a potential agent to inhibit efflux pumps in multidrug-resistant T. pyogenes.

The first reported case of pelvic inflammatory disease caused by Actinobaculum massiliense.

We report the first case of pelvic inflammatory disease (PID) caused by Actinobaculum massiliense. A 53-year-old woman attended the emergency department with symptoms compatible with a PID episode, finally resolved by intramuscular antibiotic treatment. Actinobaculum sp. was isolated by culture, and A. massiliense was confirmed by matrix assisted laser desorption time-of-flight mass spectrometry and 16S rRNA gene sequencing. Only a few cases of A. massiliense infections have been reported, and the pathogenesis of infections by these bacteria is poorly understood. The introduction of new diagnostic methods into hospital routines will improve the detection of new and little-studied pathogens.

Determination of the expression of three fimbrial subunit proteins in cultured Trueperella pyogenes.

BACKGROUND: Trueperella pyogenes is a commensal and a significant opportunistic pathogen in animals. A variety of identified or putative virulence factors are considered to significantly contribute to the occurrence of T. pyogenes infection in different species. However, these virulence factors are not fully understood. RESULTS: In the current study, the genes encoding putative fimbrial proteins, i.e. Fim A, Fim C, and Fim E, were cloned. Recombinant Fim A (rFim A), Fim C (rFim C), and Fim E (rFim E) were prepared and used to generate rabbit anti-rFim A, anti-rFim C, and anti-rFim E serum, respectively. Using these sera, we found that only Fim E was constitutively expressed in T. pyogenes. The expression level of Fim E in T. pyogenes peaked within 6-10 h of culture period in pH 7.5. Fim E protein expression was unaffected by anaerobic condition, but was inhibited by the microaerophilic condition. Tube agglutination tests indicated that Fim E was exhibited on the surface of T. pyogenes cells because anti-rFim E serum caused strong agglutination. Additionally, the blots for Fim A detection showed nonspecific reactions. Furthermore, the tube agglutination tests showed that anti-Fim A serum failed to cause agglutination of T. pyogenes cells, which indicated that Fim A was not, or poorly, expressed in cultured T. pyogenes. Anti-rFim C serum caused strong agglutination. However, the blots for Fim C detection showed a strong nonspecific reaction. Thus, the expression of Fim C was difficult to be determined using the current method. CONCLUSIONS: Fim E was expressed in cultured T. pyogenes. However, Fim A was either not or poorly expressed in cultured T. pyogenes. Moreover, Fim C expression was not determined using the current strategy.