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Xanthomonas maltophilia [keywords]
- Antifungal activity of Stenotrophomonas maltophilia in Stomoxys calcitrans larvae. [Journal Article]
- Rev Bras Parasitol Vet 2014 Apr; 23(2):194-9.
The microbiota present in Stomoxys calcitrans larvae may assist their survival in contaminated environments through production of inhibitory substances. Bacteriological identification methods, the polymerase chain reaction (PCR) and scanning electron microscopy (SEM) were used to detect a bacterium naturally present in mucus and macerated S. calcitrans larvae. The antifungal activity was determined based on the results from disk diffusion tests on an artificial solid medium. The bacterium was identified as Stenotrophomonas maltophilia and presented antifungal activity against Beauveria bassiana sensu lato isolates CG 138, CG 228 and ESALQ 986. This result suggests that the larval microbiota is a factor that can compromise the use of B. bassiana s.l. fungus for biological control of S. calcitrans larvae.
- Diaryl-Substituted Azolylthioacetamides: Inhibitor Discovery of New Delhi Metallo-β-Lactamase-1 (NDM-1). [JOURNAL ARTICLE]
- ChemMedChem 2014 Jul 22.
The emergence and spread of antibiotic-resistant pathogens is a global public health problem. Metallo-β-lactamases (MβLs) such as New Delhi MβL-1 (NDM-1) are principle contributors to the emergence of resistance because of their ability to hydrolyze almost all known β-lactam antibiotics including penicillins, cephalosporins, and carbapenems. A clinical inhibitor of MBLs has not yet been found. In this study we developed eighteen new diaryl-substituted azolylthioacetamides and found all of them to be inhibitors of the MβL L1 from Stenotrophomonas maltophilia (Ki <2 μM), thirteen to be mixed inhibitors of NDM-1 (Ki <7 μM), and four to be broad-spectrum inhibitors of all four tested MβLs CcrA from Bacteroides fragilis, NDM-1 and ImiS from Aeromonas veronii, and L1 (Ki <52 μM), which are representative of the B1a, B1b, B2, and B3 subclasses, respectively. Docking studies revealed that the azolylthioacetamides, which have the broadest inhibitory activity, coordinate to the Zn(II) ion(s) preferentially via the triazole moiety, while other moieties interact mostly with the conserved active site residues Lys224 (CcrA, NDM-1, and ImiS) or Ser221 (L1).
- Bacterial degradation of naproxen - Undisclosed pollutant in the environment. [JOURNAL ARTICLE]
- J Environ Manage 2014 Jul 12.:157-161.
The presence of non-steroidal anti-inflammatory drugs (NSAIDs) in the environment is an emerging problem due to their potential influence on human health and biocenosis. This is the first report on the biotransformation of naproxen, a polycyclic NSAID, by a bacterial strain. Stenotrophomonas maltophilia KB2 transformed naproxen within 35 days with about 28% degradation efficiency. Under cometabolic conditions with glucose or phenol as a carbon source degradation efficiency was 78% and 40%, respectively. Moreover, in the presence of naproxen phenol monooxygenase, naphthalene dioxygenase, hydroxyquinol 1,2-dioxygenase and gentisate 1,2-dioxygenase were induced. This suggests that degradation of naproxen occurs by its hydroxylation to 5,7,8-trihydroxynaproxen, an intermediate that can be cleaved by hydroxyquinol 1,2-dioxygenase. The cleavage product is probably further oxidatively cleaved by gentisate 1,2-dioxygenase. The obtained results provide the basis for the use of cometabolic systems in the bioremediation of polycyclic NSAID-contaminated environments.
- A Patient Presenting with Cholangitis due to Stenotrophomonas Maltophilia and Pseudomonas Aeruginosa Successfully Treated with Intrabiliary Colistine. [Journal Article]
- Infect Dis Rep 2014 May 13; 6(2):5147.
Anatomical barriers for antibiotic penetration can pose a particular challenge in the clinical setting. Stenotrophomonas maltophilia (SM) and Pseudomonas aeruginosa (PA) are two pathogens capable of developing multiple drug-resistance (MDR) mechanisms. We report the case of a 56-year-old female patient with a permanent percutaneous transhepatic biliary drainage (PTBD), who was admitted to our hospital with a cholangitis due to a MDR Escherichia coli strain. Upon admission, culture-guided antimicrobial therapy was conducted and the biliary catheter was replaced, with poor clinical response. Subsequently, SM and PA were detected. Treatment with fosfomycin and colistine was initiated, again without adequate response. Systemic colistine and tigecycline along with an intrabiliary infusion of colistine for 5 days was then used, followed by parenteral fosfomycin and tigecycline for 7 days. The patient was then successfully discharged. This is the first case report we are aware of on the use of intrabiliary colistine. It describes a new approach to treating cholangitis by MDR bacteria in patients with a PTBD.
- MALDI-TOF: A Useful Tool for Laboratory Identification of Uncommon Glucose Non-Fermenting Gram-Negative Bacteria Related to Cystic Fibrosis. [JOURNAL ARTICLE]
- J Med Microbiol 2014 Jun 30.
The predisposition of patients with cystic fibrosis (CF) for recurrent pulmonary infections can result in poor prognosis in disease progression. Although the clinical significance of micro-organisms such as Staphylococcus aureus, Haemophilus influenzae, and Pseudomonas aeruginosa is well established, the implication of uncommon glucose non-fermenting gram-negative bacilli (UGNF-GNB) in respiratory samples from CF patients is still unclear. Due to limitations of traditional methods used in most clinical laboratories, the accurate identification of these agents is a challenge. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) is an alternative tool for efficient identification of bacteria. This is a retrospective study to evaluate different identification methods in a collection of UGNF-GNB isolated during a period of three years from children with CF. The performance of MALDI-TOF was compared to 16S rDNA gene sequencing and to a conventional and automated phenotypic identification. The discriminatory power of MALDI-TOF (75.0% agreement) was superior to automated techniques (67.1% agreement) and conventional phenotypical identification (50.0% agreement). MALDI-TOF also demonstrated high performance in identifying Stenotrophomonas maltophilia, Achromobacter xylosoxidans, and Chryseobacterium indologenes, but it presented limitations in identifying Pandoraea spp., some species of Acinetobacter, and Chryseobacterium (other than C. indologenes). Although MALDI-TOF identified only 75% of the isolates in comparison to 16S rDNA gene sequencing, prompt identification and high discriminatory power exhibited by MALDI-TOF make it a useful tool for the characterization of micro-organisms that are difficult to identify using routine methods.
- Protocatechuate 3,4-Dioxygenase: A Wide Substrate Specificity Enzyme Isolated from Stenotrophomonas maltophilia KB2 as a Useful Tool in Aromatic Acid Biodegradation. [JOURNAL ARTICLE]
- J Mol Microbiol Biotechnol 2014 Jun 26; 24(3):150-160.
Protocatechuate 3,4-dioxygenases (P34Os) catalyze the reaction of the ring cleavage of aromatic acid derivatives. It is a key reaction in many xenobiotic metabolic pathways. P34Os characterize narrow substrate specificity. This property is an unfavorable feature in the biodegradation process because one type of pollution is rarely present in the environment. Thus, the following study aimed at the characterization of a P34O from Stenotrophomonas maltophilia KB2, being able to utilize a wide spectrum of aromatic carboxylic acids. A total of 3 mM vanillic acid and 4-hydroxybenzoate were completely degraded during 8 and 4.5 h, respectively. When cells of strain KB2 were grown on 9 mM 4-hydroxybenzoate, P34O was induced. Biochemical analysis revealed that the examined enzyme was similar to other known P34Os, but showed untypical wide substrate specificity. A high activity of P34O against 2,4- and 3,5-dihydroxybenzoate was observed. As these substrates do not possess ortho configuration hydroxyl groups, it is postulated that their cleavage could be connected with their monodentate binding of substrate to the active site. Since this enzyme characterizes untypical wide substrate specificity it makes it a useful tool in applications for environmental clean-up purposes. © 2014 S. Karger AG, Basel.
- Characterization of bacterial community of raw milk from dairy cows during subacute ruminal acidosis challenge by high-throughput sequencing. [JOURNAL ARTICLE]
- J Sci Food Agric 2014 Jun 24.
Four cannulated primiparous Holstein dairy cows (84 ± 25 DIM) were used in a 2 × 2 crossover experimental design. The two diets contained 40% (low-concentrate diet, or control diet, LC) and 70% (high-concentrate diet, or SARA induction diet, HC) concentrate feeds respectively. Milk samples were collected on days 17, 18 and 19 of each experimental period. DNA was extracted from each milk sample, and pyrosequencing was applied to analyse the milk microbial community.Regardless of diet, the bacterial community of milk was dominated by Actinobacteria, Firmicutes, Proteobacteria and Bacteroidetes. HC feeding showed a higher proportion of some mastitis-causing pathogen bacteria, such as Stenotrophomonas maltophilia, Streptococcus parauberis and Brevundimonas diminuta, as well as of psychrotrophic bacteria, such as Pseudomonas, Brevundimonas, Sphingobacterium, Alcaligenes, Enterobacter and Lactobacillus. However, the diversity of the milk bacterial microbiota (ACE, Chao, and Shannon index) was not affected by HC feeding.To the best of our knowledge, this is the first report on the use of pyrosequencing for evaluating the impacts of nutrition on changes in the composition of milk microbiota. These findings indicate that HC feeding may increase the risk of dairy cows suffering from mastitis, decrease the organoleptic quality of raw milk and dairy products, and limit the shelf life of processed fluid milk. [[ArtCopyrightmsg]].
- Clinical Factors Associated with Acquisition of Resistance to Levofloxacin in Stenotrophomonas maltophilia. [Journal Article]
- Yonsei Med J 2014 Jul 1; 55(4):987-93.
Fluoroquinolones, rapidly gaining prominence in treatment of Stenotrophomonas maltophilia (SMP), are noted for their potency and tolerability. However, SMP may rapidly acquire resistance to fluoroquinolones. We evaluated associations of clinical factors with acquisition of levofloxacin resistance (LFr) in SMP.Our retrospective cohort study was based on patient data collected between January 2008 and June 2010. Through screening of 1275 patients, we identified 122 patients with data for SMP antibiotic susceptibility testing in ≥3 serial SMP isolates.We assigned the 122 patients to either the SS group (n=54) in which levofloxacin susceptibility was maintained or the SR group (n=31) in which susceptible SMP acquired resistance. In multivariate regression analysis, exposure to levofloxacin for more than 3 weeks [odds ratio (OR) 15.39, 95% confidential interval (CI) 3.08-76.93, p=0.001] and co-infection or co-colonization with Klebsiella pneumoniae resistant to levofloxacin (OR 4.85, 95% CI 1.16-20.24, p=0.030) were independently associated with LFr acquisition in SMP.Acquisition of LFr during serial sampling of SMP was related to the levofloxacin exposure.
- [Treatment of Stenotrophomonas maltophilia meningoencephalitis with intraventricular colistin.] [JOURNAL ARTICLE]
- Farm Hosp 2014; 38(n03):252-253.
- Chronic dacryocystitis secondary to Stenotrophomonas maltophilia and Staphylococcus aureus mixed infection. [Journal Article]
- BMJ Case Rep 2014.
A 40-year-old woman with a history of recurrent attacks of dacryocystitis for 2 years developed a lacrimal sac abscess. β-Lactam antibiotics, considered the first-line treatment for dacryocystitis, were ineffective. She underwent dacryocystorhinostomy. Cultures from the lacrimal sac demonstrated the presence of Stenotrophomonas maltophilia and methicillin-sensitive Staphylococcus aureus, both of which are sensitive to trimethoprim-sulfamethoxazole. This rare and antibiotic-resistant bacterial species should be considered in atypical cases of dacryocystitis, and appropriate antibiotics should be started immediately.