-
Emerging Microbes & Infections Apr 2018The genus Myroides comprises several species of Gram-negative, non-motile, and non-fermenting bacteria, which have been regarded as non-pathogenic for decades. Multiple...
The genus Myroides comprises several species of Gram-negative, non-motile, and non-fermenting bacteria, which have been regarded as non-pathogenic for decades. Multiple recent reports, however, underscore the pathogenic potential that Myroides sp. possesses for humans. These bacteria seem to be resistant to a wide range of antibiotics (including ß-lactams and aminoglycosides). Therefore, treatment options are limited. Knowledge of antimicrobial resistance, however, is based on only one meaningful comprehensive study and on data published from case reports. This lack of data motivated us to test 59 strains from our Myroides collection (43 M. odoratimimus and 16 M. odoratus) for resistance against 20 commonly used antibiotics. We also performed molecular analyses to reveal whether our bacteria harbor the genus-specific M. odoratimimus metallo-ß-lactamase (MUS-1) or the M. odoratus metallo ß-lactamase (TUS-1), and other ß-lactamases, which may provide an explanation for the extended antimicrobial resistance.
Topics: Anti-Bacterial Agents; DNA, Bacterial; Flavobacteriaceae; Humans; Microbial Sensitivity Tests; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Whole Genome Sequencing; beta-Lactamases
PubMed: 29618738
DOI: 10.1038/s41426-018-0061-x -
Journal of Food Protection Apr 2018Uncontrolled bacterial growth and metabolic activities are responsible for the short shelf life of raw pork. Culture-independent analysis by 16S ribosome cDNA could...
Uncontrolled bacterial growth and metabolic activities are responsible for the short shelf life of raw pork. Culture-independent analysis by 16S ribosome cDNA could reveal viable bacteria in raw pork. This study investigated microbial growth and volatile organic compounds of raw pork supplemented with various preservatives. Vacuum-packaged raw pork was stored at 4°C, after soaking in solutions of potassium sorbate, ε-poly-l-lysine, kojic acid (KA), or sodium diacetate, individually. Spoilage of raw pork was monitored by determining pH and total volatile basic nitrogen, whereas bacterial growth was determined by culture-dependent and culture-independent analyses. Data indicated that all the preservatives were able to inhibit bacterial growth and extend the shelf life of pork. High-throughput sequencing of 16S ribosome cDNA indicated that Pseudomonas was inhibited under vacuum conditions, whereas facultative anaerobes ( Acinetobacter, Photobacterium, Brochothrix, and Myroides) were the most active genera in the spoiled pork. Photobacterium was further inhibited by each preservative. The inhibition of Acinetobacter, Photobacterium, and Myroides could be responsible for the extended shelf life of vacuum-packaged pork; they were effectively inhibited by KA, which also induced the longest shelf life. Moreover, 19 types of volatile organic compounds were detected. 3-Methylbutanol, 3-methylbutanol acetate, 2-butanone, toluene, benzeneacetaldehyde, dimethyl trisulfide, and acetoin were associated with spoilage. Furthermore, KA is a potential preservative in raw pork; because no phenol was detectable within 35 days, excessive intake of phenol induced by preservatives was avoided.
Topics: Animals; Food Microbiology; Food Packaging; Red Meat; Swine; Vacuum; Volatile Organic Compounds
PubMed: 29543526
DOI: 10.4315/0362-028X.JFP-17-423 -
3 Biotech Feb 2018This study focused on the identification of free cyanide (CDO) and thiocyanate (TDO) degrading microbial communities using a culture-dependent and independent approach....
This study focused on the identification of free cyanide (CDO) and thiocyanate (TDO) degrading microbial communities using a culture-dependent and independent approach. Culturable microbial species were isolated from the CDOs ( = 13) and TDOs ( = 18). The CDOs were largely dominated by sp. while the TDOs were dominated by sp., , sp. and sp. However, 16S rRNA amplicon gene-sequencing revealed the complexity and diversity of the microbial communities in contrast to the organisms that were detected using culture-dependent technique. Overall, the organisms were mainly dominated by and sp. at 37.82 and 30.5% for CDOs, and 35.26 and 17.58% for TDOs, respectively. The co-culturing of the CDOs and TDOs resulted in biochemical changes of key metabolic enzymes, and this resulted in the complete degradation of CN and SCN simultaneously; a phenomenon which has not been witnessed, especially under alkaline conditions. Current ongoing studies are focused on the application of these organisms for the biodegradation of CN and SCN in a continuous system, under changing operational parameters, to assess their effectiveness in the biodegradation of CN and SCN.
PubMed: 29430355
DOI: 10.1007/s13205-018-1124-3 -
Frontiers in Microbiology 2017is an aerobic, non-fermenting Gram-negative multidrug-resistant bacterium widely distributed in nature that rarely causes infections in immunocompromised patients. We...
is an aerobic, non-fermenting Gram-negative multidrug-resistant bacterium widely distributed in nature that rarely causes infections in immunocompromised patients. We recently described in a diabetic patient a case of recurrent calcaneal ulcer infection caused by a strain showing potential for biofilm formation. For the first time, we therefore evaluated the ability of to form biofilm under different pH values and glucose concentrations using an "skin-like" model, and its susceptibility to levofloxacin, meropenem, and tigecycline. The expression of some antibiotic-resistance related genes was also monitored by RT-PCR during planktonic-to-biofilm transition. Our results indicated that can produce relevant amounts of biofilm biomass, in a time-dependent manner, especially at acidic pH and regardless of glucose concentration tested. The comparative analysis of MIC and MBC values between planktonic and sessile cells showed that resistance to antibiotics increased during the planktonic-to-biofilm transition. Viable cell count indicated that none of the tested antibiotics were able to completely eradicate preformed biofilms, although meropenem and levofloxacin were the most active causing a significant, dose-independent, reduction of biofilm's viability, as also confirmed by microscopic analysis. RT-PCR showed that antibiotic-resistance related and genes are over-expressed during the transition from planktonic to sessile (biofilm) lifestyle. Overall, our findings showed that can form relevant amounts of inherently antibiotic-resistant biofilm under conditions relevant to wound site, therefore suggesting a role in the pathogenesis of chronic ulcer infections.
PubMed: 29312264
DOI: 10.3389/fmicb.2017.02591 -
Genome Announcements Nov 2017We report here the 4.29-Mb draft genome sequence of sp. N17-2, a new bacterium isolated from radiation-polluted soils in Xinjiang, Uyghur Autonomous Region, China. The...
We report here the 4.29-Mb draft genome sequence of sp. N17-2, a new bacterium isolated from radiation-polluted soils in Xinjiang, Uyghur Autonomous Region, China. The acquisition of its genome will provide valuable information to reveal the relationship between radiation and multidrug resistance.
PubMed: 29146839
DOI: 10.1128/genomeA.01301-17 -
PloS One 2017Interferences between pathogenic bacteria and specific commensals are known. We determined the interactions between nasopharyngeal microbial pathogens and commensals...
BACKGROUND
Interferences between pathogenic bacteria and specific commensals are known. We determined the interactions between nasopharyngeal microbial pathogens and commensals during viral upper respiratory tract infection (URI) and acute otitis media (AOM) in infants.
METHODS
We analyzed 971 specimens collected monthly and during URI and AOM episodes from 139 infants. The 16S rRNA V4 gene regions were sequenced on the Illumina MiSeq platform.
RESULTS
Among the high abundant genus-level nasopharyngeal microbiota were Moraxella, Haemophilus, and Streptococcus (3 otopathogen genera), Corynebacterium, Dolosigranulum, Staphylococcus, Acinetobacter, Pseudomonas, and Bifidobacterium. Bacterial diversity was lower in culture-positive samples for Streptococcus pneumoniae, and Haemophilus influenzae, compared to cultured-negative samples. URI frequencies were positively associated with increasing trend in otopathogen colonization. AOM frequencies were associated with decreasing trend in Micrococcus colonization. During URI and AOM, there were increases in abundance of otopathogen genera and decreases in Pseudomonas, Myroides, Yersinia, and Sphingomonas. Otopathogen abundance was increased during symptomatic viral infection, but not during asymptomatic infection. The risk for AOM complicating URI was reduced by increased abundance of Staphylococcus and Sphingobium.
CONCLUSION
Otopathogen genera played the key roles in URI and AOM occurrences. Staphylococcus counteracts otopathogens thus Staphylococcal colonization may be beneficial, rather than harmful. While Sphingobium may play a role in preventing AOM complicating URI, the commonly used probiotic Bifidobacterium did not play a significant role during URI or AOM. The role of less common commensals in counteracting the deleterious effects of otopathogens requires further studies.
Topics: Acute Disease; Anti-Bacterial Agents; Bacteria; Female; Haemophilus influenzae; Humans; Infant, Newborn; Longitudinal Studies; Male; Microbiota; Micrococcus; Nasopharynx; Otitis Media; Prospective Studies; RNA, Ribosomal, 16S; Respiratory Tract Infections; Risk Factors; Sequence Analysis, DNA; Streptococcus pneumoniae; Virus Diseases
PubMed: 28708872
DOI: 10.1371/journal.pone.0180630 -
Infection and Drug Resistance 2017Antibiotics are a relatively common disturbance to the normal microbiota of humans and agricultural animals, sometimes resulting in severe side effects such as...
Antibiotics are a relatively common disturbance to the normal microbiota of humans and agricultural animals, sometimes resulting in severe side effects such as antibiotic-associated enterocolitis. was used as a vertebrate model for effects of a broad-spectrum antibiotic, rifampicin, on the skin and gut mucosal microbiomes. The fish were exposed to the antibiotic in the water column for 1 week, and then monitored during recovery. As observed via culture, viable counts from the skin microbiome dropped strongly yet returned to pretreatment levels by 1.6 days and became >70% resistant. The gut microbiome counts dropped and took longer to recover (2.6 days), and became >90% drug resistant. The resistance persisted at ~20% of skin counts in the absence of antibiotic selection for 2 weeks. A community biochemical analysis measuring the presence/absence of 31 activities observed a 39% change in results after 3 days of antibiotic treatment. The antibiotic lowered the skin and gut microbiome community diversity and altered taxonomic composition, observed by 16S rRNA profiling. A 1-week recovery period did not return diversity or composition to pretreatment levels. The genus dominated both the microbiomes during the treatment, but was not stable and declined in abundance over time during recovery. Rifampicin selected for members of the family in the skin but not the gut microbiome. Consistent with other studies, this tractable animal model shows lasting effects on mucosal microbiomes following antibiotic exposure, including persistence of drug-resistant organisms in the community.
PubMed: 28533691
DOI: 10.2147/IDR.S129055 -
IDCases 2017species are bacteria found commonly in environmental sources, such as water and soil. Despite this, they are historically uncommon pathogens, tending to affect...
species are bacteria found commonly in environmental sources, such as water and soil. Despite this, they are historically uncommon pathogens, tending to affect primarily immunocompromised hosts. Based on a review of the current cases listed in the U.S. National Institutes of Health's National Library of Medicine (Table 1), there have been 48 reported cases of infection to date, one third of which have been reported in only the last seven years. This report outlines a case of bacteremia caused by species occurring in a diabetic male on chemotherapy for Merkel cell cancer. species can be difficult to treat, many strains are resistant to several antibacterial classes, this patient was treated successfully with meropenem.
PubMed: 28331806
DOI: 10.1016/j.idcr.2017.02.012 -
The Journal of Biological Chemistry Mar 2017Proteases play important roles in all living organisms and also have important industrial applications. Family M12A metalloproteases, mainly found throughout the animal...
Proteases play important roles in all living organisms and also have important industrial applications. Family M12A metalloproteases, mainly found throughout the animal kingdom, belong to the metzincin protease family and are synthesized as inactive precursors. So far, only flavastacin and myroilysin, isolated from bacteria, were reported to be M12A proteases, whereas the classification of myroilysin is still unclear due to the lack of structural information. Here, we report the crystal structures of pro-myroilysin from bacterium sp. cslb8. The catalytic zinc ion of pro-myroilysin, at the bottom of a deep active site, is coordinated by three histidine residues in the conserved motif HEHGH; the cysteine residue in the pro-peptide coordinates the catalytic zinc ion and inhibits myroilysin activity. Structure comparisons revealed that myroilysin shares high similarity with the members of the M12A, M10A, and M10B families of metalloproteases. However, a unique "cap" structure tops the active site cleft in the structure of pro-myroilysin, and this "cap" structure does not exist in the above structure-reported subfamilies. Further structure-based sequence analysis revealed that myroilysin appears to belong to the M12A family, but pro-myroilysin uses a "cysteine switch" activation mechanism with a unique segment, including the conserved cysteine residue, whereas other reported M12A family proteases use an "aspartate switch" activation mechanism. Thus, our results suggest that myroilysin is a new bacterial member of the M12A family with an exceptional cysteine switch activation mechanism. Our results shed new light on the classification of the M12A family and may suggest a divergent evolution of the M12 family.
Topics: Bacterial Proteins; Catalytic Domain; Conserved Sequence; Crystallization; Cysteine; Enzyme Activation; Flavobacteriaceae; Histidine; Metalloendopeptidases; Metalloproteases; Molecular Structure; Zinc
PubMed: 28188295
DOI: 10.1074/jbc.M116.758110 -
Journal of Food Protection Apr 2016The aim of this study was to investigate the phenotypic and genotypic antimicrobial resistance, integrons, and transferability of resistance markers in 243 aerobic...
The aim of this study was to investigate the phenotypic and genotypic antimicrobial resistance, integrons, and transferability of resistance markers in 243 aerobic bacteria recovered from pork at slaughter in the People's Republic of China. The organisms belonged to 22 genera of gram-negative bacteria (92.2%) and gram-positive bacteria (7.8%). High levels of resistance were detected to tetracycline, trimethoprim-sulfamethoxazole, and ampicillin (36.2 to 54.3%), and lower levels were detected to nitrofurantoin, cefotaxime, gentamicin, ciprofloxacin, and chloramphenicol (7.8 to 29.2%). Across species, genes conferring antimicrobial resistance were observed with the following frequencies: blaTEM, 40.7%; blaCMY-2, 15.2%; blaCTX-M, 11.5%; sul2, 27.2%; sul1, 14.4%; tet(A), 5.4%; tet(L), 5.4%; tet(M), 5.0%; tet(E), 3.7%; tet(C), 3.3%; tet(S), 2.5%; and tet(K), 0.8%. Various antimicrobial resistance genes were found in new carriers: blaTEM in Lactococcus garvieae, Myroides odoratimimus, Aeromonas hydrophila, Staphylococcus sciuri, Raoultella terrigena, Macrococcus caseolyticus, Acinetobacter ursingii, Sphingobacterium sp., and Oceanobacillus sp.; blaCMY-2 in Lactococcus lactis, Klebsiella oxytoca, Serratia marcescens, Acinetobacter baumannii, and Myroides phaeus; tet(L) in M. caseolyticus; sul1 in Vibrio cincinnatiensis; sul2 in Acinetobacter bereziniae, Acinetobacter johnsonii, and V. cincinnatiensis; and the class 1 integron and gene cassette aadA2 in V. cincinnatiensis. Approximately 6.6% of isolates contained class 1 integrons, and one isolate harbored class 2 integrons. Plasmid associated intI1 and androgen receptor- encoding genes were transferred into Escherichia coli J53 and E. coli DH5α by conjugation and transformation experiments, respectively. Our study highlights the importance of aerobic bacteria from pork as reservoirs for antimicrobial resistance genes and mobile genetic elements that can readily be transferred intra- and interspecies.
Topics: Abattoirs; Animals; Anti-Bacterial Agents; Bacteria; Bacterial Proteins; China; Drug Resistance, Bacterial; Food Handling; Integrons; Plasmids; Red Meat; Swine
PubMed: 27052863
DOI: 10.4315/0362-028X.JFP-15-455