-
Chemistry and Physics of Lipids Mar 2016Dermabacter hominis is a medically important actinobacterial inhabitant of human skin, although it is rarely implicated in infections. The lipid composition of D....
Dermabacter hominis is a medically important actinobacterial inhabitant of human skin, although it is rarely implicated in infections. The lipid composition of D. hominis is revisited in this study in the context of its natural resistance to daptomycin, an antibiotic whose activity is influenced by membrane lipids. Thin layer chromatography and mass spectrometry revealed that this species contains phospholipids and glycolipids. Using electrospray ionization time of flight mass spectrometry (exact mass) and gas chromatography-mass spectrometry, the major phospholipid of D. hominis was identified as plasmanyl-phosphatidylglycerol (pPG), because it presented one alkyl chain and one acyl chain in the glycerol moiety of the molecule. The structure of the major glycolipid (GL1) was studied by combined gas-liquid chromatography, mass spectrometry and nuclear magnetic resonance, and was established as galactosyl-α-(1→2)-glucosyl-alkyl-acyl-glycerol. Lipid analyses showed differences between one daptomycin-resistant (DAP-R) strain and one daptomycin-sensitive (DAP-S) strain growing in the presence of the antibiotic: DAP-R tended to accumulate GL1 and to reduce pPG, whereas DAP-S maintained high proportions of pPG. The results demonstrate the existence of ether-linked lipids in D. hominis and reveal a differential distribution of phospholipids and glycolipids according to the sensitivity or resistance to daptomycin, although the mechanism(s) operating in the resistance to the antibiotic remain(s) to be elucidated.
Topics: Actinobacteria; Ethers; Humans; Lipids; Skin; Spectrometry, Mass, Electrospray Ionization
PubMed: 26867985
DOI: 10.1016/j.chemphyslip.2016.02.002 -
International Journal of Systematic and... Apr 2016A novel actinobacterial strain, AD1-86T, was isolated from the vaginal fluid of a Korean female and was characterized by a polyphasic approach. The strain was a...
A novel actinobacterial strain, AD1-86T, was isolated from the vaginal fluid of a Korean female and was characterized by a polyphasic approach. The strain was a facultatively anaerobic, Gram-stain-positive, non-spore-forming, non-motile, catalase-positive and oxidase-negative short rod. Colonies were creamy white, of low convexity and 1-2 mm in diameter after growth on DSM 92 agar plates at 37 °C for 2 days. The most closely related strains were Dermabacter hominis DSM 7083T and Helcobacillus massiliensis 6401990T (98.3 and 96.3 % 16S rRNA gene sequence similarity, respectively). The isolate grew optimally at 37 °C and pH 7 in the presence of 0.5% (w/v) NaCl. The cell-wall peptidoglycan contained meso-diaminopimelic acid and the cell-wall hydrolysates contained ribose, galactose and glucose. The DNA G+C content was 62.6 mol% and the mean DNA-DNA relatedness value of the isolate to D. hominis DSM 7083T was 31.1±3.0% (reciprocal: 48.2±5.3%). The major cellular fatty acids (>10%) were anteiso-C17:0, anteiso-C15:0 and iso-C16:0, and the menaquinones were MK-9, MK-8 and MK-7. The polar lipid profile of strain AD1-86T consisted of diphosphatidylglycerol, phosphatidylglycerol, two aminolipids and a glycolipid. Data from this polyphasic study indicate that strain AD1-86T represents a novel species of the genus Dermabacter, for which the name Dermabacter vaginalis sp. nov. is proposed; the type strain is AD1-86T (=KCTC 39585T=DSM 100050T).
Topics: Actinomycetales; Asian People; Bacterial Typing Techniques; Base Composition; DNA, Bacterial; Diaminopimelic Acid; Fatty Acids; Female; Glycolipids; Humans; Molecular Sequence Data; Nucleic Acid Hybridization; Peptidoglycan; Phospholipids; Phylogeny; RNA, Ribosomal, 16S; Republic of Korea; Sequence Analysis, DNA; Vagina; Vitamin K 2
PubMed: 26867728
DOI: 10.1099/ijsem.0.000960 -
International Journal of Infectious... Jun 2015Breast implant infections are usually caused by Staphylococcus aureus and coagulase-negative staphylococci. Gram-negative bacilli are rarely reported to be involved in...
BACKGROUND
Breast implant infections are usually caused by Staphylococcus aureus and coagulase-negative staphylococci. Gram-negative bacilli are rarely reported to be involved in breast implant infections.
METHODS
Thirty-seven cases of microbiologically confirmed breast implant infection managed from January 2008 to June 2012 in the study centre were reviewed, including 10 cases from the study centre itself and 27 cases from private clinics in the region.
RESULTS
The prevalence of breast implant infection in the study centre was 0.74% of breast implantation, i.e., 3.23% in breast reconstruction for breast cancer and 0.27% in aesthetic breast augmentation (p=0.0002). Of the 37 cases, 30% had undergone radiotherapy and 11% had undergone a lymph node dissection. S. aureus was identified in 18 cases, Gram-negative bacilli in 10 cases, coagulase-negative staphylococci in eight cases, anaerobic bacteria in eight cases, and streptococci in three cases. Pseudomonas aeruginosa was the second most commonly identified pathogen. Staphylococcus epidermidis was the most frequent coagulase-negative Staphylococcus species. In addition to Propionibacterium acnes and Actinomyces neuii, other facultative and strict anaerobic bacteria have not been reported before, e.g., Bacteroides thetaiotaomicron, Corynebacterium simulans, Dermabacter hominis, Finegoldia magna, and Peptoniphilus harei. Seventy-percent of cases were treated by immediate implant removal. All cases treated only with antibiotics were treated with surgery at the second visit.
CONCLUSIONS
The microbiological epidemiology was noted by an increasing the proportion of Gram-negative bacteria and anaerobic bacteria detected with the advent of MALDI-TOF MS and molecular identification for diagnosis.
Topics: Adult; Aged; Bacteria; Bacterial Infections; Breast Diseases; Breast Implants; Female; France; Gram-Negative Bacteria; Humans; Mammaplasty; Middle Aged; Postoperative Complications; Pseudomonas aeruginosa; Referral and Consultation; Staphylococcus; Staphylococcus aureus; Young Adult
PubMed: 25910855
DOI: 10.1016/j.ijid.2015.04.010 -
Changes in gastric and lung microflora with acid suppression: acid suppression and bacterial growth.JAMA Pediatrics Oct 2014The use of acid suppression has been associated with an increased risk of upper and lower respiratory tract infections in the outpatient setting but the mechanism behind...
IMPORTANCE
The use of acid suppression has been associated with an increased risk of upper and lower respiratory tract infections in the outpatient setting but the mechanism behind this increased risk is unknown. We hypothesize that this infection risk results from gastric bacterial overgrowth with subsequent seeding of the lungs.
OBJECTIVES
To determine if acid-suppression use results in gastric bacterial overgrowth, if there are changes in lung microflora associated with the use of acid suppression, and if changes in lung microflora are related to full-column nonacid gastroesophageal reflux.
DESIGN, SETTING, AND PARTICIPANTS
A 5-year prospective cohort study at a tertiary care center where children ages 1 to 18 years were undergoing bronchoscopy and endoscopy for the evaluation of chronic cough. Acid-suppression use was assessed through questionnaires with confirmation using an electronic medical record review.
MAIN OUTCOMES AND MEASURES
Our primary outcome was to compare differences in concentration and prevalence of gastric and lung bacteria between patients who were and were not receiving acid-suppression therapy. We compared medians using the Wilcoxon signed rank test and determined prevalence ratios using asymptotic standard errors and 95% confidence intervals. We determined correlations between continuous variables using Pearson correlation coefficients and compared categorical variables using the Fisher exact test.
RESULTS
Forty-six percent of patients taking acid-suppression medication had gastric bacterial growth compared with 18% of untreated patients (P = .003). Staphylococcus (prevalence ratio, 12.75 [95% CI, 1.72-94.36]), Streptococcus (prevalence ratio, 6.91 [95% CI, 1.64-29.02]), Veillonella (prevalence ratio, 9.56 [95% CI, 1.26-72.67]), Dermabacter (prevalence ratio, 4.78 [95% CI, 1.09-21.02]), and Rothia (prevalence ratio, 6.38 [95% CI, 1.50-27.02]) were found more commonly in the gastric fluid of treated patients. The median bacterial concentration was higher in treated patients than in untreated patients (P = .001). There was no difference in the prevalence (P > .23) of different bacterial genera or the median concentration of total bacteria (P = .85) in the lungs between treated and untreated patients. There were significant positive correlations between proximal nonacid reflux burden and lung concentrations of Bacillus (r = 0.47, P = .005), Dermabacter (r = 0.37, P = .008), Lactobacillus (r = 0.45, P = .001), Peptostreptococcus (r = 0.37, P = .008), and Capnocytophagia (r = 0.37, P = .008).
CONCLUSIONS AND RELEVANCE
Acid-suppression use results in gastric bacterial overgrowth of genera including Staphylococcus and Streptococcus. Full-column nonacid reflux is associated with greater concentrations of bacteria in the lung. Additional studies are needed to determine if acid suppression-related microflora changes predict clinical infection risk; these results suggest that acid suppression use may need to be limited in patients at risk for infections.
Topics: Adolescent; Antacids; Bacterial Infections; Child; Child, Preschool; Female; Gastroesophageal Reflux; Humans; Hydrogen-Ion Concentration; Infant; Lung; Lung Diseases; Male; Prospective Studies; Stomach; Stomach Diseases
PubMed: 25133779
DOI: 10.1001/jamapediatrics.2014.696 -
Genome Announcements Jul 2014Dermabacter hominis is a common colonizer of the healthy human skin and is rarely detected as an opportunistic human pathogen. The genome sequence of the...
Dermabacter hominis is a common colonizer of the healthy human skin and is rarely detected as an opportunistic human pathogen. The genome sequence of the multidrug-resistant D. hominis strain 1368, isolated from blood cultures of a pyelonephritis patient, provides insights into the repertoire of antibiotic resistance genes.
PubMed: 25059872
DOI: 10.1128/genomeA.00728-14