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Foods (Basel, Switzerland) May 2022and screened from Guizhou specialty food were used to prepare fermented pork loin ham. The sensory qualities and flavor profiles of fermented pork loin hams from 0 to...
and screened from Guizhou specialty food were used to prepare fermented pork loin ham. The sensory qualities and flavor profiles of fermented pork loin hams from 0 to 42 days were investigated in order to reveal the dynamics of fermented pork loin ham. The results show that total free amino acids (TFAA) content reached the highest value on the 35th day, and the umami amino acids, including aspartic acid (ASP), glutamic acid (GLU), glycine (GLY), and alanine (ALA), were the main amino acids in all periods. Notably, the RV coefficient (0.875) indicates that free amino acids (FAA) are highly correlated with the sensory score of the E-tongue. In terms of the volatile compounds identified, the esters content gradually increased between 7 and 42 days, and ethyl octanoate was the most abundant compound during all periods. These esters imparted a characteristic aroma component to the fermented pork loin ham. The most important finding was that the increase in the content of esters represented by octanoic acid-ethyl ester might be related to the increase in the content of FAA with the increase in fermentation time. Both the E-nose and E-tongue showed good discrimination ability for fermented tenderloin ham with different fermentation times, which was crucial in cases with large clusters. In addition, the multiple factor analysis (MFA) indicated that the E-nose aroma value might be the key factor in distinguishing fermented pork loin ham with different fermentation times.
PubMed: 35627071
DOI: 10.3390/foods11101501 -
Frontiers in Cellular and Infection... 2022Mixed vaginitis is a complex vaginal dysbiosis that differs from single vaginitis. Vaginitis in the third trimester may lead to adverse maternal and neonatal outcomes....
Mixed vaginitis is a complex vaginal dysbiosis that differs from single vaginitis. Vaginitis in the third trimester may lead to adverse maternal and neonatal outcomes. The clinical characteristics, microbiological characteristics, and adverse pregnancy outcomes of mixed vaginitis in late pregnancy are worth studying. Therefore, this study investigated the clinical and microbiological characteristics of vaginitis and adverse pregnancy outcomes of patients with mixed vaginitis. We studied 1,674 women in late pregnancy who attended the Tianjin Medical University General Hospital from November, 2019 to October, 2021. We administered standardized questionnaires, performed vaginal examination and sampling plus microscope examinations, and assessed follow-up pregnancy outcomes. We cultured the vaginal discharge of the patients with mixed vaginitis to isolate pathogens and performed antimicrobial susceptibility tests of the isolated pathogens. For the patients with peripartum infection, we collected a sample to isolate pathogens. Among the 1,674 women, 66 (3.9%) had mixed vaginitis. The independent risk factor for mixed vaginitis in late pregnancy was a history of vaginitis during early and middle pregnancy (OR = 5.637, 95% CI: 3.314-9.580). The signs of vaginal erythema (63.6% 42.0%), yellow discharge (81.8% . 59.6%), and malodor (31.8% . 18.8%) (0.05) were significantly higher in patients with mixed vaginitis than in patients with single vaginitis. Bacterial isolates of the vaginal secretions of patients with mixed bacterial vaginitis were mainly the pathogens of aerobic vaginitis and bacterial vaginosis, such as , , and Pathogen isolation of the vaginal secretions of patients with mixed fungus and bacteria vaginitis mainly included , followed by , , , , and . Women with mixed vaginitis had an increased incidence and risk of peripartum infections (6.1% . 1.4%, <0.05; OR = 3.985, 95% CI:1.214-13.079). is the main pathogen that causes peripartum infection. Mixed vaginitis in late pregnancy is characterized by a severe and complex phenotype, complex vaginal dysbiosis, and a long course of vaginal dysbiosis. This can lead to an increased incidence and risk of peripartum infection. Therefore, more attention should be paid to patients with mixed vaginitis in the third trimester of pregnancy.
Topics: Cross-Sectional Studies; Dysbiosis; Escherichia coli; Female; Humans; Male; Pregnancy; Pregnancy Outcome; Pregnancy Trimester, Third; Vaginitis; Vaginosis, Bacterial; Vulvovaginitis
PubMed: 35419297
DOI: 10.3389/fcimb.2022.798738 -
Frontiers in Veterinary Science 2021An understanding of the spatio-temporal distribution of several groups of mastitis pathogens can help to inform programs for the successful control and management of...
An understanding of the spatio-temporal distribution of several groups of mastitis pathogens can help to inform programs for the successful control and management of mastitis. However, in the absence of an active surveillance program such information is not readily available. In this retrospective study we analyzed passive surveillance data from a diagnostic laboratory with an aim to describe the spatio-temporal trend of major mastitis pathogens between 2008 and 2017 in Ontario dairy cattle. Data for all milk culture samples submitted to the Animal Health Laboratory (AHL) at the University of Guelph between 2008 and 2017 was accessed. Descriptive analyses were conducted to identify the major pathogens and Chi-square goodness-of-fit tests were used to compare between multiple proportions. Likewise, univariable logistic regression analysis was performed to determine if there was a change in the probability of isolating the major mastitis pathogens depending on geography or time. Seasonality was assessed by calculating the seasonal relative risk (RR). Of a total of 85,979 milk samples examined, more than half of the samples (61.07%) showed no growth and the proportion of samples that showed no growth almost halved during the study period. Of the samples (36.21%, = 31,133) that showed any growth, the major bacterial pathogens were (15.60%), Non-aureus Staphylococci (NAS) (5.04%), spp. (2.96%), and (2.00%). Of the NAS, the major species reported were (69.02%), (14.45%), (12.99%), and (2.13%). A temporal change in the prevalence of contagious pathogens like and spp. was observed with an increasing odds of 1.06 and 1.62, respectively. Likewise, except for , the prevalence of all the major environmental mastitis pathogens increased during the study period. The isolation of most of the pathogens peaked in summer, except for , and which peaked in spring months. Interestingly, a regional pattern of isolation of some bacterial pathogens within Ontario was also observed. This study showed a marked spatio-temporal change in the prevalence of major mastitis pathogens and suggests that a regional and seasonal approach to mastitis control could be of value.
PubMed: 34805334
DOI: 10.3389/fvets.2021.742696 -
AIMS Microbiology 2021Lysostaphin is a glycylglycine endopeptidase, secreted by , capable of specifically hydrolyzing pentaglycine crosslinks present in the peptidoglycan of the cell wall....
Lysostaphin is a glycylglycine endopeptidase, secreted by , capable of specifically hydrolyzing pentaglycine crosslinks present in the peptidoglycan of the cell wall. In this paper, we describe the cloning and expression of the lysostaphin enzyme gene in WB600 host using pWB980 expression system. Plasmid pACK1 of was extracted using the alkaline lysis method. Lysostaphin gene was isolated by PCR and cloned into pTZ57R/T-Vector, then transformed into DH5α. The amplified gene fragment and uncloned pWB980 vector were digested using I and І enzymes and purified. The restricted gene fragment was ligated into the pWB980 expression vector by the standard protocols, then the recombinant plasmid was transformed into WB600 using electroporation method. The recombinant protein was evaluated by the SDS-PAGE method and confirmed by western immunoblot. Analysis of the target protein showed a band corresponding to 27-kDa r-lysostaphin. Protein content was estimated 91 mg/L by Bradford assay. The recombinant lysostaphin represented 90% of its maximum activity at 40 °C and displayed good thermostability by keeping about 80% of its maximum activity at 45 °C. Heat residual activity assay of recombinant lysostaphin demonstrated that the enzyme stability was up to 40 °C and showed good stability at 40 °C for 16 h incubation.
PubMed: 34708172
DOI: 10.3934/microbiol.2021017 -
International Journal of Molecular... Jul 2021The best-characterized members of the M23 family are glycyl-glycine hydrolases, such as lysostaphin (Lss) from or LytM from . Recently, enzymes with broad specificities...
The best-characterized members of the M23 family are glycyl-glycine hydrolases, such as lysostaphin (Lss) from or LytM from . Recently, enzymes with broad specificities were reported, such as EnpA from , that cleaves D,L peptide bond between the stem peptide and a cross-bridge. Previously, the activity of EnpA was demonstrated only on isolated peptidoglycan fragments. Herein we report conditions in which EnpA lyses bacterial cells live with very high efficiency demonstrating great bacteriolytic potential, though limited to a low ionic strength environment. We have solved the structure of the EnpA H109A inactive variant and analyzed it in the context of related peptidoglycan hydrolases structures to reveal the bases for the specificity determination. All M23 structures share a very conserved β-sheet core which constitutes the rigid bottom of the substrate-binding groove and active site, while variable loops create the walls of the deep and narrow binding cleft. A detailed analysis of the binding groove architecture, specificity of M23 enzymes and D,L peptidases demonstrates that the substrate groove, which is particularly deep and narrow, is accessible preferably for peptides composed of amino acids with short side chains or subsequent L and D-isomers. As a result, the bottom of the groove is involved in interactions with the main chain of the substrate while the side chains are protruding in one plane towards the groove opening. We concluded that the selectivity of the substrates is based on their conformations allowed only for polyglycine chains and alternating chirality of the amino acids.
Topics: Amino Acid Sequence; Bacterial Proteins; Catalytic Domain; Endopeptidases; Enterococcus faecalis; N-Acetylmuramoyl-L-alanine Amidase; Peptide Hydrolases; Peptidoglycan; Prophages; Protein Binding; Staphylococcus; Staphylococcus aureus; Substrate Specificity
PubMed: 34281200
DOI: 10.3390/ijms22137136 -
IDCases 2021Urinary tract infections (UTIs) are clinically and economically burdensome. Gram positive causative uropathogens are rare, and has infrequently been isolated as a...
Urinary tract infections (UTIs) are clinically and economically burdensome. Gram positive causative uropathogens are rare, and has infrequently been isolated as a causative agent for UTIs. Here, we present two cases of causing complicated urinary tract infections.
PubMed: 34195001
DOI: 10.1016/j.idcr.2021.e01202 -
BMJ Case Reports May 2021A 78-year-old man with an implantable cardioverter-defibrillator (ICD) presented with chills and malaise. His history was significant for heart failure with reduced...
A 78-year-old man with an implantable cardioverter-defibrillator (ICD) presented with chills and malaise. His history was significant for heart failure with reduced ejection fraction and complete heart block. He had undergone permanent pacemaker placement that was later upgraded to an ICD 5 years before his presentation. Physical examination revealed an open wound with surrounding erythema overlying the device site. Blood cultures obtained on admission were negative. Transesophageal echocardiogram did not show valve or lead vegetations. He underwent a prolonged extraction procedure. Postoperatively, he developed septic shock and cultures from the device, and repeat peripheral blood cultures grew and He was treated with intravenous vancomycin but had refractory hypotension, leading to multiorgan failure. He later expired after being transitioned to comfort care. The patient may have acquired by feeding cows on a nearby farm, and the prolonged extraction procedure may have precipitated the bacteraemia.
Topics: Aged; Animals; Bacteremia; Cattle; Defibrillators, Implantable; Humans; Male; Sepsis; Staphylococcus
PubMed: 34045192
DOI: 10.1136/bcr-2020-240309 -
Veterinary Research Apr 2021Communications via quorum sensing (QS) between non-aureus staphylococci (NAS) and Staphylococcus (S.) aureus in the bovine mammary gland remains largely unexplored. We...
Communications via quorum sensing (QS) between non-aureus staphylococci (NAS) and Staphylococcus (S.) aureus in the bovine mammary gland remains largely unexplored. We determined whether 34 S. chromogenes, 11 S. epidermidis, and 14 S. simulans isolates originating from bovine milk samples and teat apices were able to regulate the QS of S. aureus, and if so, how in vitro growth inhibition of S. aureus by NAS, or NAS metabolites, or NAS cells themselves play a role in this process. In co-culture with S. aureus we observed that these 3 NAS species in general downregulated the expression of rnaIII, the effector molecule of the QS system, but this effect was more pronounced in S. chromogenes and S. simulans isolates than in S. epidermidis isolates. In vitro growth inhibition of S. aureus by NAS resulted in a small underestimation of the downregulating effect of NAS on rnaIII expression of S. aureus. Additionally, the culture supernatant of these NAS isolates and supernatant treated with proteinase K expressed greater regulatory activity over S. aureus virulence genes rnaIII, hla, and spa than washed NAS cells suspended in sterile water. These microbial interactions may influence S. aureus virulence and pathogenesis within the host. Isolation and identification of NAS metabolites affecting the QS system of S. aureus might help to develop alternative strategies for treatment and control of S. aureus mastitis.
Topics: Animals; Bacterial Proteins; Down-Regulation; Gene Expression Regulation, Bacterial; Mammary Glands, Animal; Milk; Quorum Sensing; Staphylococcus; Staphylococcus aureus; Trans-Activators
PubMed: 33926572
DOI: 10.1186/s13567-021-00933-x -
BMC Infectious Diseases Jan 2021Exotoxins secreted from Staphylococcus aureus or Streptococcus pyogenes act as superantigens that induce systemic release of inflammatory cytokines and are a common...
BACKGROUND
Exotoxins secreted from Staphylococcus aureus or Streptococcus pyogenes act as superantigens that induce systemic release of inflammatory cytokines and are a common cause of toxic shock syndrome (TSS). However, little is known about TSS caused by coagulase-negative staphylococci (CoNS) and the underlying mechanisms. Here, we present a rare case of TSS caused by Staphylococcus simulans (S. simulans).
CASE PRESENTATION
We report the case of a 75-year-old woman who developed pneumococcal pneumonia and bacteremia from S. simulans following an influenza infection. The patient met the clinical criteria for probable TSS, and her symptoms included fever of 39.5 °C, diffuse macular erythroderma, conjunctival congestion, vomiting, diarrhea, liver dysfunction, and disorientation. Therefore, the following treatment was initiated for bacterial pneumonia complicating influenza A with suspected TSS: meropenem (1 g every 8 h), vancomycin (1 g every 12 h), and clindamycin (600 mg every 8 h). Blood cultures taken on the day after admission were positive for CoNS, whereas sputum and pharyngeal cultures grew Streptococcus pneumoniae (Geckler group 4) and methicillin-sensitive S. aureus, respectively. However, exotoxins thought to cause TSS, such as TSS toxin-1 and various enterotoxins, were not detected. The patient's therapy was switched to cefazolin (2 g every 8 h) and clindamycin (600 mg every 8 h) for 14 days based on microbiologic test results. She developed desquamation of the fingers on hospital day 8 and was diagnosed with TSS. Conventional exotoxins, such as TSST-1, and S. aureus enterotoxins were not detected in culture samples. The serum levels of inflammatory cytokines, such as neopterin and IL-6, were high. CD8+ T cells were activated in peripheral blood. Vβ2+ population activation, which is characteristic for TSST-1, was not observed in the Vβ usage of CD8+ T cells in T cell receptor Vβ repertoire distribution analysis.
CONCLUSIONS
We present a case of S. simulans-induced TSS. Taken together, we speculate that no specific exotoxins are involved in the induction of TSS in this patient. A likely mechanism is uncontrolled cytokine release (i.e., cytokine storm) induced by non-specific immune reactions against CoNS proliferation.
Topics: Aged; Anti-Bacterial Agents; Blood Culture; Cefazolin; Clindamycin; Cytokine Release Syndrome; Cytokines; Female; Humans; Microbial Sensitivity Tests; Shock, Septic; Sputum; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus; Streptococcus pneumoniae; Treatment Outcome
PubMed: 33407229
DOI: 10.1186/s12879-020-05731-y -
Journal of Applied Microbiology Sep 2021Staphylococcus aureus, an opportunistic pathogen, causes diverse community and nosocomial-acquired human infections, including folliculitis, impetigo, sepsis, septic... (Review)
Review
Staphylococcus aureus, an opportunistic pathogen, causes diverse community and nosocomial-acquired human infections, including folliculitis, impetigo, sepsis, septic arthritis, endocarditis, osteomyelitis, implant-associated biofilm infections and contagious mastitis in cattle. In recent days, both methicillin-sensitive and methicillin-resistant S. aureus infections have increased. Highly effective anti-staphylococcal agents are urgently required. Lysostaphin is a 27 kDa zinc metallo antimicrobial lytic enzyme that is produced by Staphylococcus simulans biovar staphylolyticus and was first discovered in the 1960s. Lysostaphin is highly active against S. aureus strains irrespective of their drug-resistant patterns with a minimum inhibitory concentration of ranges between 0·001 and 0·064 μg ml . Lysostaphin has activity against both dividing and non-dividing S. aureus cells; and can seep through the extracellular matrix to kill the biofilm embedded S. aureus. In spite of having excellent anti-staphylococcal activity, its clinical application is hindered because of its immunogenicity and reduced bio-availability. Extensive research with lysostaphin lead to the development of several engineered lysostaphin derivatives with reduced immunogenicity and increased serum half-life. Therapeutic efficacy of both native and engineered lysostaphin derivatives was studied by several research groups. This review provides an overview of the therapeutic applications of native and engineered lysostaphin derivatives developed to eradicate S. aureus infections.
Topics: Animals; Anti-Bacterial Agents; Cattle; Female; Lysostaphin; Methicillin-Resistant Staphylococcus aureus; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus
PubMed: 33382154
DOI: 10.1111/jam.14985