Antibiotic resistance of Mycoplasma Synoviae strains isolated in China from 2016 to 2019

Background In the past decade, Mycoplasma synoviae (M. synoviae) infection has become widely prevalent in China, has caused serious economic losses and has become one of the most important diseases in the chicken industry. Medication is a general approach for the control of M. synoviae infection, but antibiotics are sometimes ineffective in clinical practice. To investigate the sensitivity of M. synoviae to antimicrobials commonly used in the treatment of M. synoviae infection, the antibiotic susceptibility of 32 M. synoviae strains isolated from China from 2016 to 2019 were determined using the minimum inhibitory concentration (MIC) method. Results All isolates had low MIC values for the combination of lincomycin and spectinomycin, pleuromutilin, and macrolides. However, the M. synoviae isolates displayed variance in MICs for doxycycline hydrochloride with a range of 0.25 to 8 μg/mL, and oxytetracycline hydrochloride with a range of 0.5 to 8 μg/mL. Three and one M. synoviae isolates showed intermediate MIC values to doxycycline hydrochloride and oxytetracycline hydrochloride, respectively. High MIC values for enrofloxacin were detected in all isolates with MICs ranging from 4 to 32 μg/mL. Furthermore, comparison of the parC QRDR identified a mutation at nucleotide position 254 (C254T) resulting in a Thr 85 Ile amino acid change in all M. synoviae isolates and the reference strain ATCC 25204 being resistant to enrofloxacin. Moreover, mutations at Glu 804 Gly and Thr 686 Ala of gyrA QRDR were identified in all M. synoviae isolates and ATCC 25204. The mutation in the QRDR of the parE gene resulted in amino acid changes at positions 197 (Pro to Ser) in 27/32 M. synoviae isolates. Conclusion Three nonsynonymous mutations in gyrA and parE were first identified to be related to enrofloxacin resistance. Our results showed that M. synoviae resistance to enrofloxacin is widespread.

Lactiplantibacillus plantarum 1201 Inhibits Intestinal Infection of Salmonella enterica subsp. Enterica serovar Typhimurium Strain ATCC 13311 in Mice with High-Fat Diet

Salmonella Typhimurium is widely distributed in food. It can colonise the gastrointestinal tract after ingestion, causing lamina propria edema, inflammatory cell infiltration, and mucosal epithelial decomposition. A high-fat diet (HFD) can induce an inflammatory response, but whether HFD can increase the infection level of S. Typhimurium is unknown. We established a model of Salmonella enterica subsp. enterica serovar Typhimurium strain ATCC 13311 ATCC 13311 infection in healthy adult mice with a maintenance diet (MD) or HFD to explore the effect of Lactiplantibacillus plantarum 1201 intervention on S. Typhimurium ATCC 13311 colonization and its protective effects on mice. HFD exacerbated the infection of S. Typhimurium ATCC 13311, while the intervention of L. plantarum 1201 effectively mitigated this process. L. plantarum 1201 can reduce the colonies of S. ATCC 13311 in the intestines and tissues; and reduce intestinal inflammation by down-regulating the level of TLR4/NF-κB pathway related proteins in serum and the expression of related inflammatory factors in the colon and jejunum. Since L. plantarum 1201 can inhibit the colonization of S. Typhimurium ATCC 13311 and relieve inflammation in HFD, current research may support the use of L. plantarum 1201 to prevent S. Typhimurium infection.

The Blepharisma stoltei macronuclear genome: towards the origins of whole genome reorganization

The germ-soma distinction is a defining feature of multicellular eukaryotes. Analogous to this, ciliates, a ubiquitous microbial eukaryote lineage, have morphologically and functionally distinct nuclei, but within single cells: the germline micronucleus (MIC) and somatic macronucleus (MAC). The origins and mechanisms of the MIC to MAC transformation, especially the extensive elimination of abundant internally eliminated sequences (IESs) and transposons during genome reorganization, are great biological mysteries. Blepharisma represents one of the two earliest diverging ciliate classes, and has unique, dual pathways of MAC development, making it ideal for investigating the functioning, origins and evolution of these processes. Here, we report the MAC genome assembly of Blepharisma stoltei strain ATCC 30299 (41 Mb), arranged as numerous alternative telomere-capped minichromosomes, tens to hundreds of kilobases long. The B. stoltei MAC genome encodes eight PiggyBac transposase homologs liberated from transposons. All are subject to purifying selection, but just one, the putative Blepharisma IES excisase, has a complete catalytic amino acid triad. Numerous genes encoding other domesticated transposases are present in B. stoltei, and often are comparably strongly upregulated in a similar timeframe to model ciliate genome reorganization homologs. Our phylogenetic investigations suggest the PiggyBac homologs may have been ancestral ciliate IES excisases. The B. stoltei MAC genome, together with the upcoming MIC genome, highlights the evolution and complex interplay between transposons, domesticated transposases, and genome reorganization in the context of germline-soma differentiation within single cells.

Detection of Campylobacter jejuni and Salmonella typhimurium in chicken using PCR for virulence factor hipO and invA genes (Saudi Arabia)

Campylobacter jejuni and Salmonella typhimurium are the leading causes of bacterial food contamination in chicken carcasses. Contamination is particularly associated with the slaughtering process. The present study isolated C. jejuni and S. typhimurim from fifty chicken carcass samples, all of which were acquired from different companies in Riyadh, Saudi Arabia. The identification of C. jejuni was performed phenotypically by using a hippurate test and genetically using a polymerase chain reaction with primers for 16S rRNA and hippurate hydrolase (hipO gene). For the dentification of S. typhimurim, a serological Widal test was carried out using serum anti-S. typhimurium antibodies. Strains were genetically detected using invA gene primers. The positive isolates for C. jejuni showed a specific molecular size of 1448 bp for 16S rRNA and 1148 bp for hipO genes. However, the positive isolates of the invA gene exhibited a specific molecular size at 244 bp using polymerase chain reaction (PCR). Comparing sequencing was performed with respect to the invA gene and the BLAST nucleotide isolates that were identified as Salmonella enterica subsp. enterica serovar typhimurium strain ST45, thereby producing a similarity of 100%. The testing identified C.jejuni for hippuricase, GenBank: Z36940.1. While many isolates of Salmonella spp. that contained the invA gene were not necessarily identified as S. typhimurim, the limiting factor for the Widal test used antiS. typhimurum antibodies. The multidrug resistance (MDR) of C. jejuni isolates in chickens was compared with the standard C. jejuni strain ATCC 22931. Similarly, S. typhimurium isolates were compared with the standard S. typhimurium strain ATCC 14028.

Vfr or CyaB promote the expression of the pore-forming toxin exlBA operon in Pseudomonas aeruginosa ATCC 9027 without increasing its virulence in mice

Pseudomonas aeruginosa is a wide-spread γ-proteobacterium that produces the biosurfactant rhamnolipid that has a great commercial value due to excellent properties of low toxicity and high biodegradability. However, this bacterium is an opportunist pathogen that constitutes an important health hazard due to its production of virulence-associated traits and its high antibiotic resistance. Thus, it is highly desirable to have a non-virulent P. aeruginosa strain for rhamnolipid production. It has been reported that strain ATCC 9027 is avirulent in mouse models of infection, and it is still able to produce rhamnolipid. Thus, it has been proposed to be suitable for it industrial production, since it encodes a defective LasR quorum sensing (QS) transcriptional regulator that is the head of this regulatory network. However, the restoration of virulence factor production by overexpression of rhlR (the gene encoding a QS-transcriptional regulator which is under the transcriptional control of LasR) is not sufficient to restore its virulence in mice. It is desirable to obtain a deeper understanding of ATCC 9027 attenuated-virulence phenotype and to assess the safety of this strain to be used at an industrial scale. In this work we determined whether increasing the expression of the pore-forming toxin encoded by the exlBA operon in strain ATCC 9027 had an impact on its virulence using Galleria mellonella and mouse models of infections. We increased the expression of the exlBA operon by overexpressing from a plasmid its transcriptional activator Vfr or of the Vfr ligand cyclic AMP produced by CyaB. We found that in G. mellonella ATCC 9027/pUCP24-vfr and ATCC 9027/pUCP24-cyaB gained a virulent phenotype, but these strains remained avirulent in murine models of P. aeruginosa infection. These results reinforce the possibility of using ATCC 9027 for industrial biosurfactants production.

Complete Genome Sequence of Lactobacillus crispatus Type Strain ATCC 33820

The complete genome sequence of Lactobacillus crispatus type strain ATCC 33820 was obtained by combining Nanopore and Illumina sequencing technologies. The genome consists of a 2.2-Mb circular chromosome with 2,194 open reading frames and an average GC content of 37.0%.

The gigA/gigB Genes Regulate the Growth, Stress Response, and Virulence of Acinetobacter baumannii ATCC 17978 Strain

Acinetobacter baumannii is an important pathogen of nosocomial infection. Recently, a group of genes, named “gig” (for Growth in Galleria), have been identified in a contemporary multi-drug resistant clinical isolate of A. baumannii—strain AB5075. Among these so-called gig genes, gigA and gigB were found to promote antibiotic resistance, stress survival, and virulence of AB5075 by interacting with the nitrogen phosphotransferase system (PTSNtr). This study aimed to investigate the roles of gigA/gigB, which appear to comprise a stress-signaling pathway (encoding for an atypical two-component system response regulator and a predicted anti-anti-sigma factor, respectively), and the involvement of ptsP (encoding the Enzyme I component of the PTSNtr) in the growth, stress resistance, and virulence of the widely studied A. baumannii strain ATCC 17978. Genetic analyses of strains harboring mutations of gigA and gigB were performed to investigate the roles of these genes in bacterial growth, stress resistance, evading macrophage defense, and killing of Galleria mellonella larva. In contrast with findings from strain AB5075 where gigA and gigB contribute to aminoglycoside resistance, the data presented herein indicate that the loss of gigA/gigB does not impact antibiotic resistance of strain ATCC 17978. Interestingly, however, we found that deletion of gigA/gigB in the ATCC 17978 background imparts a general growth in laboratory medium and also conferred growth and replication defects within murine macrophages and an inability to kill G. mellonella larvae. Importantly, studies as well as the loss of ptsP restored the phenotypes of the gigA/gigB mutant to that of the wild-type. The data presented herein indicate that in A. baumannii ATCC 17978, the gigA/gigB genes play a key role in both growth and virulence traits, but are dispensable for other stress-resistance survival phenotypes, including aminoglycoside resistance. Our findings thus highlight several similarities and also important differences between the gigA/gigB stress-signaling pathway in two commonly studied isolates of this troublesome pathogen.

Lipid and carotenoid production by Rhodosporodium toruloides ATCC 204091 using C5 and C6 sugars obtained from lignocellulosic hydrolysate

Aim: This study investigated the production of lipids and carotenoids and associated growth properties by the oleaginous red yeast Rhodosporodium toruloides strain ATCC 204091, using C5 and C6 sugar streams of lignocellulosic waste hydrolysate separately and in combination (C5+C6). Methodology: Cell density, wet and dry biomass weight, concentration of total sugars and reducing sugars were determined at various time intervals during cell growth in media containing C5, C6 and mixed sugars. Lipid and carotenoids were extracted and the media were compared with respect to production. Results: Production of lipid (22.25%) and carotenoids (19 mg l-1) was highest in C6 sugar, as compared to mixed sugars and C5 sugar. Interpretation: Due to the versatility of Rhodosporodium toruloides strain ATCC 204091 for utilizing C6 and C5 sugars present in waste hydrolysates, it has been projected as a good choice for cultivation in “waste” hydrolysates.

High-Quality Genome Reconstruction of Candida albicans CHN1 Using Nanopore and Illumina Sequencing and Hybrid Assembly

We report an improved, nearly closed, high-quality draft genome of the Candida albicans CHN1 strain (ATCC MYA-4779), a human isolate, using Illumina and Nanopore sequencing. Covering six complete and two partial nuclear chromosomes along with a partial mitochondrial genome, this assembly is 14,787,852 bases in size, with 5,935 genes.