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1.
Arianna Pompilio Valentina Crocetta Pamela Confalone Mauro Nicoletti Andrea Petrucca Simone Guarnieri Ersilia Fiscarelli Vincenzo Savini Raffaele Piccolomini Giovanni Di Bonaventura 《BMC microbiology》2010,10(1):102
Background
Stenotrophomonas maltophilia has recently gained considerable attention as an important emerging pathogen in cystic fibrosis (CF) patients. However, the role of this microorganism in the pathophysiology of CF lung disease remains largely unexplored. In the present study for the first time we assessed the ability of S. maltophilia CF isolates to adhere to and form biofilm in experimental infection experiments using the CF-derived bronchial epithelial IB3-1cell line. The role of flagella on the adhesiveness of S. maltophilia to IB3-1 cell monolayers was also assessed by using fliI mutant derivative strains. 相似文献2.
Karina Calvopiña Punyawee Dulyayangkul Kate J. Heesom Matthew B. Avison 《Molecular microbiology》2020,113(2):492-503
The β-lactam antibiotic ceftazidime is one of the handful of drugs with proven clinical efficacy against the important opportunistic human pathogen Stenotrophomonas maltophilia. Here, we show that mutations in the energy transducer TonB, encoded by smlt0009 in S. maltophilia, confer ceftazidime resistance and smlt0009 mutants have reduced uptake of ceftazidime. This breaks the dogma that β-lactams enter Gram-negative bacteria only by passive diffusion through outer membrane porins. We also show that ceftazidime-resistant TonB mutants are cross-resistant to fluoroquinolone antimicrobials and a siderophore-conjugated lactivicin antibiotic designed to target TonB-dependent uptake. This implies that attempts to improve the penetration of antimicrobials into S. maltophilia by conjugating them with TonB substrates will suffer from the fact that β-lactams and fluoroquinolones coselect resistance to these novel and otherwise promising antimicrobials. Finally, we show that smlt0009 mutants already exist among S. maltophilia clinical isolates and have reduced susceptibility to siderophore-conjugated lactivicin, despite the in vitro growth impairment seen in smlt0009 mutants selected in the laboratory. 相似文献
3.
Ohnishi M Sawada T Marumo K Harada K Hirose K Shimizu A Hayashimoto M Sato R Uchida N Kato H 《Letters in applied microbiology》2012,54(6):572-576
Aims: To evaluate the antimicrobial susceptibility and genetic relatedness of 11 Stenotrophomonas maltophilia isolates from an outbreak of bovine clinical mastitis in one herd and two isolates from two separate mastitis cases in two other herds. Methods and Results: Thirteen S. maltophilia isolates were obtained from milk samples from 11 cows from three dairy herds in Japan during 2008. We tested their susceptibility to 14 antimicrobials by broth microdilution and identified their genotypes by enterobacterial repetitive intergenic consensus 2 (ERIC2)‐PCR. Every cow had acute mild mastitis (slightly watery foremilk with flakes) without systemic symptoms and all resolved within 3–5 weeks of diagnosis. Eleven of the 13 isolates derived from nine cows in one herd over a 7‐month period exhibited a closely related ERIC2 type (A). The remaining two isolates derived from two cows from two other herds exhibited two distinct ERIC2 types (B and C). Most of the 13 isolates exhibited susceptibility to trimethoprim‐sulfamethoxazole, chloramphenicol, minocycline and levofloxacin; however, they were resistant to four β‐lactams, kanamycin, gentamicin and oxytetracycline. They were intermediate to enrofloxacin. Conclusions: Eleven closely related S. maltophilia isolates were involved in a herd outbreak of mastitis to some extent. Bovine S. maltophilia isolates exhibited resistance to many classes of antimicrobials. Significance and impact of study: This is a rare report of a herd outbreak of bovine mastitis involving closely related S. maltophilia isolates. 相似文献
4.
Background
The optimal therapy for infections caused by Stenotrophomonas maltophilia (S. maltophilia) has not yet been established. The objective of our study was to evaluate the efficacy of trimethoprim/sulfamethoxazole (SXT), minocycline, tigecycline, moxifloxacin, levofloxacin, ticarcillin-clavulanate, polymyxin E, chloramphenicol, and ceftazidime against clinical isolated S. maltophilia strains by susceptibility testing and carried out time-kill experiments in potential antimicrobials.Methods
The agar dilution method was used to test susceptibility of nine candidate antimicrobials, and time-killing experiments were carried out to evaluate the efficacy of SXT, minocycline, tigecycline, moxifloxacin, levofloxacin, and ceftazidime both alone and in combinations at clinically relevant antimicrobial concentrations.Results
The susceptibility to SXT, minocycline, tigecycline, moxifloxacin, levofloxacin, ticarcillin-clavulanate, chloramphenicol, polymyxin E, and ceftazidime were 93.8%, 95.0%, 83.8%, 80.0%, 76.3%, 76.3%, 37.5%, 22.5%, and 20.0% against 80 clinical consecutively isolated strains, respectively. Minocycline and tigecycline showed consistent active against 22 SXT-resistant strains. However, resistance rates were high in the remaining antimicrobial agents against SXT-resistant strains. In time-kill experiments, there were no synergisms in most drug combinations in time-kill experiments. SXT plus moxifloxacin displayed synergism when strains with low moxifloxacin MICs. Moxifloxacin plus Minocycline and moxifloxacin plus tigecycline displayed synergism in few strains. No antagonisms were found in these combinations. Overall, compared with single drug, the drug combinations demonstrated lower bacterial concentrations. Some combinations showed bactericidal activity.Conclusions
In S. maltophilia infections, susceptibility testing suggests that minocycline and SXT may be considered first-line therapeutic choices while tigecycline, moxifloxacin, levofloxacin, and ticarcillin-clavulanate may serve as second-line choices. Ceftazidime, colistin, and chloramphenicol show poor active against S. maltophilia. However, monotherapy is inadequate in infection management, especially in case of immunocompromised patients. Combination therapy, especially SXT plus moxifloxacin, may benefit than monotherapy in inhibiting or killing S. maltophilia. 相似文献5.
6.
A pBBad22T-derived conditioned arabinose (Ara)-inducible expression system was evaluated in Stenotrophomonas maltophilia (an opportunistic pathogen and has gained increasing attention as a cause of healthcare-associated infection). S. maltophilia cannot grow well when Ara is the sole available carbon source. The induction kinetic study, optimal inducer concentration
determination, and depletion experiment were performed by using a xylE gene fusion construct, pBxylE, to monitor the expression of pBBad22T in S. maltophilia. For induction survey, the expression of catechol 2,3-dioxygenase (C23O), encoded by xylE gene, continuously increases during an 8-h induced course and can be modulated by different inducer concentrations. The applied
induction condition of pBBad22T in S. maltophilia is the inducer concentration ranging from 0.1% to 0.5% for an induction time of 4 h. For repression evaluation, the C23O
expression is rapidly turned off within 30 min after the removal of Ara. Accordingly, the established Ara-inducible system
can provide a convenient tool for the study of S. maltophilia. 相似文献
7.
Shuyu Wu Eirini Chouliara Lars Bogø Jensen Anders Dalsgaard 《Acta veterinaria Scandinavica》2008,50(1):38
Background
Screening and enumeration of antimicrobial resistant Escherichia coli directly from samples is needed to identify emerging resistant clones and obtain quantitative data for risk assessment. Aim of this study was to evaluate the performance of 3M™ Petrifilm™ Select E. coli Count Plate (SEC plate) supplemented with antimicrobials to discriminate antimicrobial-resistant and non-resistant E. coli. 相似文献8.
The Impact of spgM,rpfF, rmlA Gene Distribution on Biofilm Formation in Stenotrophomonas maltophilia
Background
Stenotrophomonas maltophilia is emerging as one of the most frequently found bacteria in chronic pulmonary infection. Biofilm is increasingly recognized as a contributing factor to disease pathogenesis. In the present study, a total of 37 isolates of S. maltophilia obtained from chronic pulmonary infection patients were evaluated to the relationship between biofilm production and the relative genes expression.Methods
The clonal relatedness of isolates was determined by pulse-field gel electrophoresis. Biofilm formation assays were performed by crystal violet assay, and confirmed by Electron microscopy analysis and CLSM analysis. PCR was employed to learn gene distribution and expression.Results
Twenty-four pulsotypes were designated for 37 S. maltophilia isolates, and these 24 pulsotypes exhibited various levels of biofilm production, 8 strong biofilm-producing S. maltophilia strains with OD492 value above 0.6, 14 middle biofilm-producing strains with OD492 average value of 0.4 and 2 weak biofilm-producing strains with OD492 average value of 0.19. CLSM analysis showed that the isolates from the early stage of chronic infection enable to form more highly structured and multilayered biofim than those in the late stage. The prevalence of spgM, rmlA, and rpfF genes was 83.3%, 87.5%, and 50.0% in 24 S. maltophilia strains, respectively, and the presence of rmlA, spgM or rpfF had a close relationship with biofilm formation but did not significantly affect the mean amount of biofilm. Significant mutations of spgM and rmlA were found in both strong and weak biofilm-producing strains.Conclusion
Mutations in spgM and rmlA may be relevant to biofilm formation in the clinical isolates of S. maltophilia. 相似文献9.
Background
In Sweden, knowledge about the role of enteropathogenic Escherichia coli in neonatal calf diarrhea and the occurrence of antimicrobial resistance in E. coli from young calves is largely unknown. This has therapeutic concern and such knowledge is also required for prudent use of antimicrobials. 相似文献10.
Parasto Mirzaagha Marie Louie Ranjana Sharma L Jay Yanke Ed Topp Tim A McAllister 《BMC microbiology》2011,11(1):78
Background
Feedlot cattle in North America are routinely fed subtherapeutic levels of antimicrobials to prevent disease and improve the efficiency of growth. This practice has been shown to promote antimicrobial resistance (AMR) in subpopulations of intestinal microflora including Escherichia coli. To date, studies of AMR in feedlot production settings have rarely employed selective isolation, therefore yielding too few AMR isolates to enable characterization of the emergence and nature of AMR in E. coli as an indicator bacterium. E. coli isolates (n = 531) were recovered from 140 cattle that were housed (10 animals/pen) in 14 pens and received no dietary antimicrobials (control - 5 pens, CON), or were intermittently administered subtherapeutic levels of chlortetracycline (5 pens-T), chlortetracycline + sulfamethazine (4 pens-TS), or virginiamycin (5 pens-V) for two separate periods over a 9-month feeding period. Phenotype and genotype of the isolates were determined by susceptibility testing and pulsed field gel electrophoresis and distribution of characterized isolates among housed cattle reported. It was hypothesized that the feeding of subtherapeutic antibiotics would increase the isolation of distinct genotypes of AMR E. coli from cattle. 相似文献11.
Joanna Nakonieczna Ewelina Michta Magda Rybicka Mariusz Grinholc Anna Gwizdek-Wiśniewska Krzysztof P Bielawski 《BMC microbiology》2010,10(1):323
Background
Staphylococcus aureus, a major human pathogen causes a wide range of disease syndromes. The most dangerous are methicillin-resistant S. aureus (MRSA) strains, resistant not only to all β-lactam antibiotics but also to other antimicrobials. An alarming increase in antibiotic resistance spreading among pathogenic bacteria inclines to search for alternative therapeutic options, for which resistance can not be developed easily. Among others, photodynamic inactivation (PDI) of S. aureus is a promising option. Photodynamic inactivation is based on a concept that a non toxic chemical, called a photosensitizer upon excitation with light of an appropriate wavelength is activated. As a consequence singlet oxygen and other reactive oxygen species (e.g. superoxide anion) are produced, which are responsible for the cytotoxic effect towards bacterial cells. As strain-dependence in photodynamic inactivation of S. aureus was observed, determination of the molecular marker(s) underlying the mechanism of the bacterial response to PDI treatment would be of great clinical importance. We examined the role of superoxide dismutases (Sod) in photodynamic inactivation of S. aureus as enzymes responsible for oxidative stress resistance. 相似文献12.
The complete genome, comparative and functional analysis of Stenotrophomonas maltophilia reveals an organism heavily shielded by drug resistance determinants 总被引:3,自引:0,他引:3
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Crossman LC Gould VC Dow JM Vernikos GS Okazaki A Sebaihia M Saunders D Arrowsmith C Carver T Peters N Adlem E Kerhornou A Lord A Murphy L Seeger K Squares R Rutter S Quail MA Rajandream MA Harris D Churcher C Bentley SD Parkhill J Thomson NR Avison MB 《Genome biology》2008,9(4):R74-13
Background
Stenotrophomonas maltophilia is a nosocomial opportunistic pathogen of the Xanthomonadaceae. The organism has been isolated from both clinical and soil environments in addition to the sputum of cystic fibrosis patients and the immunocompromised. Whilst relatively distant phylogenetically, the closest sequenced relatives of S. maltophilia are the plant pathogenic xanthomonads.Results
The genome of the bacteremia-associated isolate S. maltophilia K279a is 4,851,126 bp and of high G+C content. The sequence reveals an organism with a remarkable capacity for drug and heavy metal resistance. In addition to a number of genes conferring resistance to antimicrobial drugs of different classes via alternative mechanisms, nine resistance-nodulation-division (RND)-type putative antimicrobial efflux systems are present. Functional genomic analysis confirms a role in drug resistance for several of the novel RND efflux pumps. S. maltophilia possesses potentially mobile regions of DNA and encodes a number of pili and fimbriae likely to be involved in adhesion and biofilm formation that may also contribute to increased antimicrobial drug resistance.Conclusion
The panoply of antimicrobial drug resistance genes and mobile genetic elements found suggests that the organism can act as a reservoir of antimicrobial drug resistance determinants in a clinical environment, which is an issue of considerable concern. 相似文献13.
Rogelio J Palomino-Morales Tomas R Vazquez-Rodriguez Orlando Torres Inmaculada C Morado Santos Castañeda Jose A Miranda-Filloy Jose L Callejas-Rubio Benjamin Fernandez-Gutierrez Miguel A Gonzalez-Gay Javier Martin 《Arthritis research & therapy》2010,12(2):R51
Introduction
The objective was to investigate the potential implication of the IL18 gene promoter polymorphisms in the susceptibility to giant-cell arteritis (GCA). 相似文献14.
Line E Thomsen Caroline T Gottlieb Sanne Gottschalk Tim T Wodskou Hans-Henrik Kristensen Lone Gram Hanne Ingmer 《BMC microbiology》2010,10(1):307
Background
Host defence peptides (HDPs), also known as antimicrobial peptides (AMPs), have emerged as potential new therapeutics and their antimicrobial spectrum covers a wide range of target organisms. However, the mode of action and the genetics behind the bacterial response to HDPs is incompletely understood and such knowledge is required to evaluate their potential as antimicrobial therapeutics. Plectasin is a recently discovered HDP active against Gram-positive bacteria with the human pathogen, Staphylococcus aureus (S. aureus) being highly susceptible and the food borne pathogen, Listeria monocytogenes (L. monocytogenes) being less sensitive. In the present study we aimed to use transposon mutagenesis to determine the genetic basis for S. aureus and L. monocytogenes susceptibility to plectasin. 相似文献15.
Giuseppantonio Maisetta Maria Luisa Mangoni Semih Esin Giuseppe Pichierri Anna Lisa Capria Franca Lisa Brancatisano Mariagrazia Di Luca Simona Barnini Donatella Barra Mario Campa Giovanna Batoni 《Peptides》2009,30(9):1622-1626
In this study the bactericidal effect of the N-terminal fragment of the frog skin peptide esculentin-1b [Esc(1–18)] in combination with clinically used antimicrobial agents was evaluated against Stenotrophomonas maltophilia, either in standard conditions (phosphate buffer) or in the presence of human serum. A synergistic bactericidal effect was observed after a 24 h incubation when combinations of Esc(1–18) and amikacin or colistin were used against clinical strains of S. maltophilia with or without resistance to these antibiotics, both in buffer and in the presence of serum. An indifferent effect was observed when the peptide was combined with levofloxacin or ceftazidime. A synergistic effect was also observed at earlier time points when the peptide was used in combination with colistin. Sequential exposure of bacterial cells to Esc(1–18) and amikacin or colistin, or vice versa, indicated that while Esc(1–18) and colistin cooperated in enhancing the bactericidal effect of their combination, when Esc(1–18) was combined with amikacin, the peptide had a major role in initiating the bactericidal effect, while amikacin was required for the subsequent effector phase. Altogether, the results obtained indicate that exposure of S. maltophilia to sub-bactericidal concentrations of Esc(1–18) increases its susceptibility to amikacin or colistin and may also render resistant strains susceptible to these antibiotics. 相似文献
16.
Early attempts to develop an animal model of infection appeared to support the hypothesis that Stenotrophomonas maltophilia does not cause serious sepsis when bacteria are intravenously administered to mice. This species has also been implicated
in an increasing number of infections such as, bacteremia, endocarditis, ophthalmological syndromes, skin lesions, urinary,
respiratory tract and gastrointestinal infections. Despite this clinical importance, the mechanisms involved in the pathogenesis
of S. maltophilia infections have not been elucidated and the virulence factors of importance in the pathogenesis of S. maltophilia associated pulmonary infection remain to be characterized. The purpose of this study was to establish an infection model
using 5 clinical isolates of S. maltophilia in a mouse pneumonia model. All strains were able to establish themselves in respiratory tract with peak of infection occurring
at 24 h post infection. The strains were able to cause neutrophil influx, were taken up and intracellularly killed by alveolar
macrophages except Sm2 that persisted for a slightly longer time in the macrophages. All strains were resistant to lytic action
of serum and survived in blood confirming their ability to cause bacteremia. The strains were cleared from spleen and liver
by 7th and 4th day but caused tissue damage that was measured in terms of lipid peroxidation, lactate dehydrogenase activity
and histopathological examination of lung tissue homogenate. All strains caused interstitial pneumonitis in lungs of mice. 相似文献
17.
Background
Brucellaspp. are highly similar, having identical 16S RNA. However, they have important phenotypic differences such as differential susceptibility to antibiotics binding the ribosome. Neither the differential susceptibility nor its basis has been rigorously studied. Differences found among other conserved ribosomal loci could further define the relationships among the classicalBrucellaspp. 相似文献18.
Background
Extended spectrum ß-lactamases (ESBLs) represent a major group of lactamases responsible for resistance, mostly produced by gram-negative bacteria, to newer generations of ß-lactam drugs currently being identified in large numbers worldwide. The present study was undertaken to see the frequency of ESBL producing Pseudomonas spp. isolated from six hundred clinical specimens (wound, pus, aural, urine, sputum, throat and other swabs) collected over a period of three years from two tertiary care hospitals in Bangladesh.Findings
Aerobic bacterial culture was performed on aseptically collected swabs and only growth of Pseudomonas was considered for further species identification and ESBL production along with serotyping of Pseudomonas aeruginosa. Antimicrobial susceptibility testing was carried out using the Kirby-Bauer agar diffusion method and ESBL production was detected on Mueller Hinton agar by double-disk synergy technique using Amoxicillin-Clavulanic acid with Ceftazidime, Cefotaxime, Ceftriaxone and Aztreonam. Culture yielded 120 Pseudomonas spp. and 82 of them were biochemically characterized for species. Pseudomonas aeruginosa was found to be the predominant (90.2%) species. Of 82 isolates tested for ESBL, 31 (37.8%) were ESBL positive with 29 (93.5%) as Pseudomonas aeruginosa, the remaining 2 (6.5%) were Stenotrophomonas maltophilia and Ralstonia pickettii. Antibiogram revealed Imipenem as the most effective drug (93.3%) among all antimicrobials used against Pseudomonas spp. followed by Aminoglycosides (63.7%).Conclusion
ESBL producing Pseudomonas spp. was found to be a frequent isolate from two tertiary care hospitals in Bangladesh, showing limited susceptibility to antimicrobials and decreased susceptibility to Imipenem in particular, which is a matter of great concern. 相似文献19.
Mohammad Jahangir Alam David Renter Ethel Taylor Diana Mina Rodney Moxley David Smith 《Current microbiology》2009,58(4):354-359
Salmonella enterica in cattle production systems may be associated with important human and animal disease issues. However, tremendous diversity
exists among Salmonella recovered, and more information is needed about strains of greatest potential health concern, particularly those that are
multidrug resistant (MDR). By characterizing Salmonella isolates from commercial feedlot pens, this study aimed to evaluate the strain diversity and prevalence of MDR Salmonella from different types of composite pen samples. Antimicrobial susceptibility profiles, serotype, and presence or absence of
the integron-encoded intI1 gene were determined for 530 Salmonella isolates recovered using composite rope (n = 335), feces (n = 59), and water (n = 136) samples from 21 pens in 3 feedlots. The study investigated only pens with available isolates from multiple sample
types. Most isolates (83.0%) of the 19 Salmonella serotypes identified were susceptible or intermediately susceptible to all the antimicrobials evaluated. Resistance to sulfisoxazole
(14.9%), streptomycin (3.8%), and tetracycline (3.6%) were the most common. None of the isolates tested positive for a class
1 integron, and only 2.5% were resistant to multiple antimicrobials. All the MDR isolates, namely, serotypes Uganda (n = 9), Typhimurium (n = 2), and Give (n = 2), were resistant to at least five antimicrobials. Most MDR isolates (n = 11) were from two pens during 1 week within one feedlot. Overall, many Salmonella isolates collected within a pen were similar in terms of serotype and antimicrobial susceptibility regardless of sample type.
However, MDR Salmonella and rare serotypes were not recovered frequently enough to suggest a general strategy for appropriate composite sampling
of feedlot cattle populations for Salmonella detection and monitoring. 相似文献
20.
In this study, the enhanced degradation of TNT using cultures of genome-shuffled Stenotrophomonas maltophilia OK-5 mt-3 has been examined and the proteome of shuffled strain was compared to the wild-type OK-5 strain. Genome shuffling
of S. maltophilia OK-5 was used to achieve a rapid enhancement of TNT degradation. The initial mutant population was generated by NTG treatment
and UV irradiation. The wild-type OK-5 strain was able to degrade 0.2 mM TNT within 6 days, yet barely tolerated 0.5 mM TNT
while the shuffled OK-5 mt-3 was capable of completely degrading 0.5 mM TNT within 8 days, and 1.2 mM within 24 days. The
proteomic analysis of the shuffled OK-5 mt-3 demonstrated the changes in the expression levels of certain proteins compared
to wild-type OK-5. These results provide clues for understanding TNT tolerance and improved TNT degradation by shuffled S. maltophilia OK-5 mt-3 and have possible applications in the processing of industrial waste containing relatively high TNT concentrations. 相似文献