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BMC Microbiology Nov 2022Macrococcus caseolyticus is an opportunistic pathogen that is frequently isolated from dairy products and veterinary infections. Recent studies have reported the...
Macrococcus caseolyticus is an opportunistic pathogen that is frequently isolated from dairy products and veterinary infections. Recent studies have reported the possibility of methicillin resistance that be transferred among staphylococcal species in foods. The present study examined the population structure, antimicrobial resistance, virulence factors, and morphology of methicillin-resistant M. caseolyticus by investigation of 94 genomes derived from both isolates in beef (n = 7) and pork (n = 2) at Shanghai and those deposited in public domain (n = 85). Phylogenetically, M. caseolyticus were divided into four clades, which each consisted of genomes isolated from continent of European countries (82.4%, n = 78), Asian countries (11.3%, n = 10), United States (4.1%, n = 4), Australia (1%, n = 1), and Sudan (1%, n = 1). The M. caseolyticus isolated from present study formed a genetically distinguished clade, which was characterized by novel alleles in the traditional 7-gene MLST scheme. Furthermore, we identified 24 AMR genes that were associated with 10 classes of antimicrobial agents in M. caseolyticus. Most AMR genes were carried by dominant plasmids such as rep7a, rep22 and repUS56. The genomes in the global clades carried significantly less AMR genes (p < 0.05) and more virulence factors (p < 0.001) than present clade. Virulence factors were detected in methicillin resistant M. caseolyticus including genes coding hemolysin, adherence, biofilm formation, exotoxin, and capsule that associated to human health and infection. Finally, as the close relative of the genus Staphylococcus, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed for morphological comparison that M. caseolyticus has a larger diameter and thicker cell wall compared with S. aureus ATCC 25,923. Taken together, our study suggested that M. caseolyticus mediating divergent antimicrobial resistance and virulence factors could serve as the vector for methicillin resistance habitats in foodborne microorganisms.
Topics: Cattle; Animals; Humans; Methicillin Resistance; Anti-Bacterial Agents; Multilocus Sequence Typing; Virulence Factors; Staphylococcus aureus; Drug Resistance, Bacterial; Phylogeny; China; Staphylococcus; Staphylococcal Infections; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests
PubMed: 36335318
DOI: 10.1186/s12866-022-02679-8 -
Journal of Dairy Science Dec 2023The possible contribution of brine-derived microflora to the sensory attributes of cheese is still a rather unexplored field. In this study, 365 bacteria and 105 yeast...
The possible contribution of brine-derived microflora to the sensory attributes of cheese is still a rather unexplored field. In this study, 365 bacteria and 105 yeast strains isolated from 11 cheese brines were qualitatively tested for proteolytic and lipolytic activities, and positive strains were identified by sequencing. Among bacteria, Staphylococcus equorum was the most frequent, followed by Macrococcus caseolyticus and Corynebacterium flavescens. As for yeasts, Debaryomyces hansenii, Clavispora lusitaniae, and Torulaspora delbrueckii were most frequently identified. A total of 38% of bacteria and 59% of yeasts showed at least 1 of the metabolic activities tested, with lipolytic activity being the most widespread (81% of bacteria and 95% of yeasts). Subsequently 15 strains of bacteria and 10 yeasts were inoculated in a curd-based medium and assessed via headspace-solid phase microextraction coupled with gas chromatography-mass spectrometry to determine their volatilome. After a 30-d incubation at 12°C, most strains showed a viability increase of about 2 log cfu/mL, suggesting good adaptability to the cheese environment. A total of 26 compounds were detected in the headspace, carbonyl compounds and alcohols being the major contributors to the volatile profile of the curd-based medium. Multivariate analysis was carried out to elucidate the overall differences in volatiles produced by selected strains. Principal component analysis and hierarchical clustering analysis demonstrated that the brine-related microorganisms were separated into 3 different groups, suggesting their different abilities to produce volatile compounds. Some of the selected strains have been shown to have interesting aromatic potential and to possibly contribute to the sensory properties of cheese.
Topics: Animals; Salts; Yeasts; Bacteria; Gas Chromatography-Mass Spectrometry; Cheese
PubMed: 37641243
DOI: 10.3168/jds.2022-23051 -
Microbiology Resource Announcements Jun 2021The complete genome sequence of Macrococcus canis strain 19/EPI0118, isolated from a veterinary clinic environment in Switzerland, was determined using hybrid assembly...
The complete genome sequence of Macrococcus canis strain 19/EPI0118, isolated from a veterinary clinic environment in Switzerland, was determined using hybrid assembly of Oxford Nanopore and Illumina reads. 19/EPI0118 harbored the methicillin resistance genes and on a staphylococcal cassette chromosome element and a chromosomal resistance island, respectively.
PubMed: 34080896
DOI: 10.1128/MRA.00408-21 -
Scientific Reports Mar 2017Methicillin-resistant Macrococcus caseolyticus strains from bovine and canine origins were found to carry a novel mecD gene conferring resistance to all classes of...
Methicillin-resistant Macrococcus caseolyticus strains from bovine and canine origins were found to carry a novel mecD gene conferring resistance to all classes of β-lactams including anti-MRSA cephalosporins. Association of β-lactam resistance with mecD was demonstrated by gene expression in S. aureus and deletion of the mecD-containing island in M. caseolyticus. The mecD gene was located either on an 18,134-bp M. caseolyticus resistance island (McRI-1) or a 16,188-bp McRI-2. Both islands were integrated at the 3' end of the rpsI gene, carried the mecD operon (mecD-mecR1-mecI), and genes for an integrase of the tyrosine recombinase family and a putative virulence-associated protein (virE). Apart from the mecD operon, that shared 66% overall nucleotide identity with the mecB operon, McRI islands were unrelated to any mecB-carrying elements or staphylococcal cassette chromosome mec. Only McRI-1 that is delimitated at both ends by direct repeats was capable of circular excision. The recombined excision pattern suggests site-specific activity of the integrase and allowed identification of a putative core attachment site. Detection of rpsI-associated integrases in Bacillus and S. aureus reveals a potential for broad-host range dissemination of the novel methicillin resistance gene mecD.
Topics: Animals; Bacterial Proteins; Base Sequence; Cattle; Chromosome Mapping; Chromosomes, Bacterial; DNA, Bacterial; Dogs; Genes, Bacterial; Host Specificity; Methicillin Resistance; Operon; Phylogeny; Staphylococcaceae; Staphylococcal Infections
PubMed: 28272476
DOI: 10.1038/srep43797 -
Foods (Basel, Switzerland) May 2024Dry-aged beef has been long favored by people due to its unique flavor and taste. However, the inner relationship between its overall quality formation and microbial...
Dry-aged beef has been long favored by people due to its unique flavor and taste. However, the inner relationship between its overall quality formation and microbial changes during dry aging has not yet received much attention and research. To deeply reveal the forming mechanism of the unique flavor and taste of dry-aged beef, correlations between its three main quality indicators, i.e., texture, free amino acids (FAAs), volatile flavor compounds (VFCs), and microbial succession were analyzed in this study. The results showed that spp. and spp. were key strains that influenced the total quality of dry-aged beef and strongly correlated with chewiness, hardness, and sweet FAAs (Ala), providing beef with unique palatability and taste. Additionally, among VFCs, spp. and spp. showed a strong correlation with octanal and heptanal, and meanwhile, those highly correlated with nonanal, pentanol, and oct-1-en-3-ol were spp., spp., and spp., respectively, providing beef with a unique flavor. spp. was proposed to be the dominant genus for dry-aged beef. This study provides valuable reference for the understanding of the role of microorganisms involved in dry aging.
PubMed: 38790852
DOI: 10.3390/foods13101552 -
Applied and Environmental Microbiology Oct 2019belongs to the normal bacterial flora of dairy cows and does not usually cause disease. However, methicillin-resistant strains were isolated from bovine mastitis milk....
belongs to the normal bacterial flora of dairy cows and does not usually cause disease. However, methicillin-resistant strains were isolated from bovine mastitis milk. These bacteria had acquired a chromosomal island (McRI -1 or McRI -2) carrying the methicillin resistance gene To gain insight into the distribution of McRI types in from cattle, 33 -containing strains from Switzerland were characterized using molecular techniques, including multilocus sequence typing, antibiotic resistance gene identification, and PCR-based McRI typing. In addition, the same genetic features were analyzed in 27 -containing strains isolated from bovine bulk milk in England/Wales using publicly available whole-genome sequences. The 60 strains belonged to 24 different sequence types (STs), with strains belonging to ST5, ST6, ST21, and ST26 observed in both Switzerland and England/Wales. McRI -1 was found in different STs from Switzerland ( = 19) and England/Wales ( = 4). McRI -2 was only found in 7 strains from Switzerland, all of which belonged to ST6. A novel island, McRI -3, which contains a complete operon ( [where the subscript indicates ]) combined with the left part of McRI -2 and the right part of McRI -1, was found in heterogeneous STs from both collections (Switzerland, = 7; England/Wales, = 21). Two strains from England/Wales carried a truncated McRI -3. Phylogenetic analyses revealed no clustering of strains according to geographical origin or carriage of McRI -1 and McRI -3. Circular excisions were also detected for McRI -1 and McRI -3 by PCR. The analyses indicate that these islands are mobile and may spread by horizontal gene transfer between genetically diverse strains. Since its first description in 2017, the methicillin resistance gene has been detected in strains from different cattle sources and countries. Our study provides new insights into the molecular diversity of -carrying strains by using two approaches to characterize elements: (i) multiplex PCR for molecular typing of McRI and (ii) read mapping against reference sequences to identify McRI types In combination with multilocus sequence typing, this approach can be used for molecular characterization and surveillance of carrying .
Topics: Animals; Bacterial Typing Techniques; Cattle; Chromosomes, Bacterial; England; Female; Genes, Bacterial; Genetic Variation; Genomic Islands; Methicillin Resistance; Microbial Sensitivity Tests; Milk; Multilocus Sequence Typing; Phylogeny; Staphylococcaceae; Wales
PubMed: 31375493
DOI: 10.1128/AEM.01496-19 -
Microbial Genomics Aug 2018Species of the genus Macrococcus are widespread commensals of animals but are becoming increasingly recognised as veterinary pathogens. They can encode methicillin...
Species of the genus Macrococcus are widespread commensals of animals but are becoming increasingly recognised as veterinary pathogens. They can encode methicillin resistance and are implicated in its spread to the closely-related, but more pathogenic, staphylococci. In this study we have identified 33 isolates of methicillin-resistant Macrococcus caseolyticus from bovine bulk tank milk from England and Wales. These isolates were characterised to provide insight into the molecular epidemiology of M. caseolyticus and to discern the genetic basis for their methicillin resistance. Antimicrobial susceptibility testing was performed by Vitek2 and disc diffusion. Isolates were whole-genome sequenced to evaluate phylogenetic relationships and the presence of methicillin resistance determinants, mecA-D. All 33 isolates were phenotypically methicillin-resistant according to cefoxitin disc diffusion, cefoxitin Etest and oxacillin resistance assessed by Vitek2. In contrast only a single isolate was resistant in the Vitek2 cefoxitin screen. Twenty-seven isolates were positive for mecD and six were positive for mecB. mecA and mecC were not detected. The results of phylogenetic analysis indicated that these methicillin-resistant isolates represented a heterogeneous population with both mecB and mecD found in diverse isolates. Isolates had a widespread distribution across the sampled region. Taken together with the role of M. caseolyticus in veterinary infections, including bovine mastitis, and in the potential spread of methicillin resistance to more pathogenic staphylococci, this work highlights the need to better understand their epidemiology and for increased awareness among veterinary microbiology laboratories.
Topics: Animals; Anti-Bacterial Agents; Cattle; England; Female; Genome, Bacterial; Mastitis, Bovine; Methicillin Resistance; Microbial Sensitivity Tests; Milk; Phylogeny; Staphylococcaceae; Wales
PubMed: 29916803
DOI: 10.1099/mgen.0.000191 -
Characterization of coagulase-negative staphylococci and macrococci isolated from cheese in Germany.Journal of Dairy Science Oct 2022Cheese, especially ripened varieties, harbor a very complex and heterogeneous microbiota. In addition to the desired microorganisms (starter cultures) added during...
Cheese, especially ripened varieties, harbor a very complex and heterogeneous microbiota. In addition to the desired microorganisms (starter cultures) added during cheese production, potentially harmful bacteria may also enter the production chain. Regarding the latter, the focus of this study was on coagulase-negative staphylococci (CNS) and Macrococcuscaseolyticus. Both are known to harbor a variety of genes coding for antibiotic resistance, including mecA, mecB, mecC, and mecD. Coagulase-negative staphylococci or macrococci carrying such genes or other virulence factors should not be present in cheese. Cheese samples (101 in total) were collected from retail sources. Coagulase-negative staphylococci and M. caseolyticus were isolated utilizing selective agars, and species were identified by phenotypical tests and partial sequencing of the sodA gene. The results allowed identification of 53 CNS strains and 19 M. caseolyticus strains. Among the CNS, 11 isolates of Staphylococcus saprophyticus and one Staphylococcus epidermidis isolate were obtained. Both species are potential human pathogens and may thus adversely affect the safety of these food products. Screening for antimicrobial resistance was performed by application of disc diffusion tests, a gradient strip-test, and 14 different PCR tests. Evidence for methicillin resistance (by either positive disc diffusion assay for cefoxitin or by mec PCR) was found in CNS isolates and M. caseolyticus (9 isolates each). Regarding other virulence factors, no genetic determinants for coagulase or the most common staphylococcal enterotoxins sea, seb, sec, sed, and see were detected in any of the CNS or M. caseolyticus isolates by PCR testing. In conclusion, the presence of facultatively pathogenic CNS and carriers of genes for antibiotic resistance in both groups of microorganisms, especially mec genes, and the respective food safety issues need further evaluation and surveillance.
Topics: Animals; Anti-Infective Agents; Cefoxitin; Cheese; Coagulase; Enterotoxins; Humans; Staphylococcus; Virulence Factors
PubMed: 35965117
DOI: 10.3168/jds.2022-21941 -
Frontiers in Physiology 2024To investigate the impact of the effect of high temperature stimulation on larvae after a certain period of time, five experimental groups were established at different...
To investigate the impact of the effect of high temperature stimulation on larvae after a certain period of time, five experimental groups were established at different temperatures. Then, the under high temperature stress was fed at 30°C for 70 days. After that, the growth index of the was counted and analyzed. In terms of growth index, high temperature stress had significant effects on FCR, FBW, WGR, and SGR of ( 0.05). The SR increased after being stimulated by temperature ( 0.1). The study revealed that liver cells of were harmed by elevated temperatures of 36°C and 38°C. In the experimental group, the activities of digestive enzymes changed in the same trend, reaching the highest point in the 32°C group and then decreasing, and the AMS activity in the 38°C group was significantly different from that in the 30°C group ( < 0.05). The activities of antioxidase in liver reached the highest at 34°C, which was significantly different from those at 30°C ( < 0.05). In addition, the expression levels of , , , and other genes increased in the experimental group, reaching the highest point at 34°C, and the expression level of the gene reached the highest point at 32°C, which was significantly different from that at 30°C ( < 0.05). However, the expression level of the gene decreased in the experimental group and reached its lowest point at 34°C ( < 0.05). The expression level of the gene increased with the highest temperature stimulus and reached its highest point at 38°C ( < 0.05). In the α diversity index of intestinal microorganisms in the experimental group, the observed species, Shannon, and Chao1 indexes in the 34°C group were the highest ( < 0.05), and β diversity analysis revealed that the intestinal microbial community in the experimental group was separated after high temperature stimulation. At the phylum level, the three dominant flora are , , and . and abundance increased at the genus level, but and abundance decreased. To sum up, appropriate high-temperature stress can enhance the immunity and adaptability of . These results show that the high temperature stimulation of 32°C-34°C is beneficial to the industrial culture of .
PubMed: 38720786
DOI: 10.3389/fphys.2024.1397818 -
Journal of Food Science and Technology Oct 2022The bacterial composition of naturally fermented Indian food, was studied by high-throughput Illumina amplicon sequencing at different taxonomic levels. Metagenomic...
UNLABELLED
The bacterial composition of naturally fermented Indian food, was studied by high-throughput Illumina amplicon sequencing at different taxonomic levels. Metagenomic investigation revealed fold change with respect to some of the phylotypes in 06 to 12 h of fermentation, suggesting the synergistic mode of nutrition. After 12 h fermentation, bacterial populations were stabilized towards 15 h fermentation. The bacterial phyla found as and others in various proportions with respective to fermentation time. Among these and were the predominant bacterial associates in this product. Initially at 0 h time interval (7%) and (93%) were present adequately in the product which has been changed to (68%), (31%) at the end of the fermentation (15 h). Phylum represented various major genus such as and whereas revealed the presence of and genus. Co-occurrence and Co-exclusion network were developed to ensure the positive and negative association in the eubacterial genus detected in entire batter fermentation event. Some genera like and are showing increase in abundances in auxiliary succession events can be established for starter culture development.
SUPPLEMENTARY MATERIAL
The online version contains supplementary material available at 10.1007/s13197-022-05421-4.
PubMed: 36193360
DOI: 10.1007/s13197-022-05421-4