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Xanthomonas maltophilia [keywords]
- Rapid identification of Stenotrophomonas maltophilia by peptide nucleic acid fluorescence in situ hybridization. [Journal Article]
- New Microbes New Infect 2014 May; 2(3):79-81.
The objective of this study was to develop a novel peptide nucleic acid (PNA) probe for Stenotrophomonas maltophilia identification by fluorescence in situ hybridization (FISH). The probe was evaluated using 33 human and veterinary clinical S. maltophilia isolates and 45 reference strains representing common bacterial species in the respiratory tract. The probe displayed 100% sensitivity and 100% specificity on pure cultures and allowed detection in sputum from cystic fibrosis patients. The detection limit was 10(4) CFU/mL in spiked tracheal aspirate and bronchoalveolar lavage from healthy horses. Altogether the study shows that this species-specific PNA FISH probe facilitates rapid detection of S. maltophilia in biological specimens.
- Antibiotic-resistant gram-negative bacterial infections in patients with cancer. [Journal Article]
- Clin Infect Dis 2014 Nov 15.:S335-9.
Patients with cancer are at high risk for infections caused by antibiotic resistant gram-negative bacteria. In this review, we summarize trends among the major pathogens and clinical syndromes associated with antibiotic resistant gram-negative bacterial infection in patients with malignancy, with special attention to carbapenem and expanded-spectrum β-lactam resistance in Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia-all major threats to our cancer patients. Optimal therapy for these antibiotic-resistant pathogens still remains to be determined.
- [A retrospective clinicopathological study of aspiration pneumonia in the elderly]. [English Abstract, Journal Article]
- Zhonghua Jie He He Hu Xi Za Zhi 2014 Aug; 37(8):592-6.
To explore the clinicopathological characteristics of aspiration pneumonia in the elderly.The clinical data of 30 cases of autopsy-proven aspiration pneumonia in Beijing Hospital from 1973 to 2002 were reviewed. The patients consisted of 28 males and 2 females, aged from 63 to 103 [mean (83 ± 9)] years.Only 15 cases were clinically diagnosed as aspiration pneumonia before death. Concomitant diseases were severe and complex, mostly coronary disease, cerebrovascular disease, hypertension, COPD, and diabetes mellitus. All the patients suffered from at least 3 concomitant diseases. Long-term bedridden and nasogastric feeding was seen in 11 and 17 patients respectively. The clinical presentation and chest X-ray of aspiration pneumonia in the elderly were nonspecific and variable. Mixed infections were common . The main bacteria isolated were Gram-negative bacilli, in particular Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Escherichia coli and Candida albicans. By pathology, macrophages with foreign bodies were found in all the 30 cases and multiple small abscesses were found in 14 cases. The lesions were adjacent to the bronchioles and in the lung tissue around the bronchioles, mostly multi-lobar and bilateral. Unilateral or bilateral pleural effusion developed in 20 patients. The accordance between radiological and pathological diagnosis of aspiration pneumonia was very poor. The foci of infection detected by X-ray were proven by autopsy in 13 patients, while pleural effusions in X-ray were proven by autopsy in 15 patients.Multi-concomitant diseases, mixed infection and extra-pulmonary presentations were common in elderly patients with aspiration pneumonia. Multiple small abscesses were the pathological characteristics of aspiration pneumonia in the aged. A definite clinical diagnosis of aspiration pneumonia was difficult. Recurrent silent microaspiration was a feature of aspiration in the elderly. The assessment of risk factor of aspiration played an important role in the clinical diagnosis of aspiration pneumonia.
- In vitro efficacy of high dose tobramycin against Burkholderia cepacia complex and Stenotrophomonas maltophilia isolates from cystic fibrosis patients. [JOURNAL ARTICLE]
- Antimicrob Agents Chemother 2014 Oct 27.
Burkholderia cepacia complex and Stenotrophomonas maltophilia infection are associated with poor clinical outcomes in persons with cystic fibrosis (CF). The minimum inhibitory concentration (MIC50) based on planktonic growth and biofilm inhibitory concentration (BIC50) of tobramycin was measured for 180 B. cepacia complex and 101 S. maltophilia CF isolates and were 100 μg/ml for both species. New inhalation devices that deliver high tobramycin levels to the lung may be able to exceed these minimum inhibitory concentrations.
- Evaluation of a new monochloramine generation system for controlling legionella in building hot water systems. [Journal Article]
- Infect Control Hosp Epidemiol 2014 Nov; 35(11):1356-63.
Objective.To evaluate the efficacy of a new monochloramine generation system for control of Legionella in a hospital hot water distribution system. Setting. A 495-bed tertiary care hospital in Pittsburgh, Pennsylvania. The hospital has 12 floors covering approximately 78,000 m(2). Methods. The hospital hot water system was monitored for a total of 29 months, including a 5-month baseline sampling period prior to installation of the monochloramine system and 24 months of surveillance after system installation (postdisinfection period). Water samples were collected for microbiological analysis (Legionella species, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Acinetobacter species, nitrifying bacteria, heterotrophic plate count [HPC] bacteria, and nontuberculous mycobacteria). Chemical parameters monitored during the investigation included monochloramine, chlorine (free and total), nitrate, nitrite, total ammonia, copper, silver, lead, and pH.
Results.A significant reduction in Legionella distal site positivity was observed between the pre- and postdisinfection periods, with positivity decreasing from an average of 53% (baseline) to an average of 9% after monochloramine application ([Formula: see text]). Although geometric mean HPC concentrations decreased by approximately 2 log colony-forming units per milliliter during monochloramine treatment, we did not observe significant changes in other microbial populations.
Conclusions.This is the first evaluation in the United States of a commercially available monochloramine system installed on a hospital hot water system for Legionella disinfection, and it demonstrated a significant reduction in Legionella colonization. Significant increases in microbial populations or other negative effects previously associated with monochloramine use in large municipal cold water systems were not observed.
- Novel Cyclic di-GMP Effectors of the YajQ Protein Family Control Bacterial Virulence. [Journal Article]
- PLoS Pathog 2014 Oct; 10(10):e1004429.
Bis-(3',5') cyclic di-guanylate (cyclic di-GMP) is a key bacterial second messenger that is implicated in the regulation of many critical processes that include motility, biofilm formation and virulence. Cyclic di-GMP influences diverse functions through interaction with a range of effectors. Our knowledge of these effectors and their different regulatory actions is far from complete, however. Here we have used an affinity pull-down assay using cyclic di-GMP-coupled magnetic beads to identify cyclic di-GMP binding proteins in the plant pathogen Xanthomonas campestris pv. campestris (Xcc). This analysis identified XC_3703, a protein of the YajQ family, as a potential cyclic di-GMP receptor. Isothermal titration calorimetry showed that the purified XC_3703 protein bound cyclic di-GMP with a high affinity (Kd∼2 µM). Mutation of XC_3703 led to reduced virulence of Xcc to plants and alteration in biofilm formation. Yeast two-hybrid and far-western analyses showed that XC_3703 was able to interact with XC_2801, a transcription factor of the LysR family. Mutation of XC_2801 and XC_3703 had partially overlapping effects on the transcriptome of Xcc, and both affected virulence. Electromobility shift assays showed that XC_3703 positively affected the binding of XC_2801 to the promoters of target virulence genes, an effect that was reversed by cyclic di-GMP. Genetic and functional analysis of YajQ family members from the human pathogens Pseudomonas aeruginosa and Stenotrophomonas maltophilia showed that they also specifically bound cyclic di-GMP and contributed to virulence in model systems. The findings thus identify a new class of cyclic di-GMP effector that regulates bacterial virulence.
- Stenotrophomonas maltophilia Pseudo-outbreak at a University Hospital Bronchoscopy Unit in Turkey. [JOURNAL ARTICLE]
- West Indian Med J 2014 Apr 8; 63(1):64-66.
Stenotrophomonas maltophilia is an opportunistic pathogen found predominantly in the environment and hospital setting. Invasive procedures and treatment methods, instruments used for diagnosis and irrational antibiotic use play major roles in the spread of this pathogen. The study aimed to evaluate consecutive S maltophilia isolation from bronchoalveolar lavage samples during bronchoscopy procedure during a week.Four patients consecutively had S maltophilia isolated during bronchoscopy between September 8 and 15, 2012. The identification of the isolates and their antibiotic susceptibility were studied by automated Vitek version 2.0 (Biomerieux, France) system. The clonal relationship between the isolates was studied by Enterobacterial repetitive intergenic consensus (ERIC) polymerase chain reaction (PCR).Four consecutive S maltophilia isolates had identical band patterns and showed clonal relatedness.Bronchoscopy is a common invasive procedure that is utilized in chest diseases departments and intensive care units (ICUs). Contamination may take place due to inappropriate use and spread of infectious pathogens. In the current study, we detected consecutive S maltophilia strains with identical band patterns isolated within a week. After appropriate disinfection and cleaning procedures, no further isolation was detected.
- Highly efficient transformation of Stenotrophomonas maltophilia S21, an environmental isolate from soil, by electroporation. [JOURNAL ARTICLE]
- J Microbiol Methods 2014 Oct 6.
Stenotrophomonas maltophilia is an emerging opportunistic pathogen, which also exhibits potential of wide applications in industry, environment and agriculture. An efficient transformation method for S. maltophilia would be convenient to its genetic studies. In this report, we focused on developing an efficient transformation protocol for S. maltophilia. Gene transfer by three different methods (chemical transformation, conjugation and electroporation) indicated that electroporation was the most efficient method to transform S. maltophilia S21. Then, the entire electroporation process from competent-cell preparation to post-pulse incubation was optimized to get higher efficiencies. Utilizing competent cells prepared at optical density (600 nm) of 1.0, the maximal transformation efficiency of S. maltophilia S21 reached 1.53×10(8) transformants/μg of pBBR1MCS DNA at a field strength of 18 kV/cm, a time constant of 4.8 ms (200 Ω), a DNA amount of 100 ng and a cell concentration of 2.4×10(8) CFU/ml after 3 h incubation. Moreover, we successfully transformed the other four isolates of S. maltophilia using this protocol. To date, this is the first report about electroporation of S. maltophilia and it will facilitate the further study of this species.
- Stenotrophomonas maltophilia Infection Among Young Children in a Cardiac Intensive Care Unit: A Single Institution Experience. [JOURNAL ARTICLE]
- Pediatr Cardiol 2014 Oct 8.
Stenotrophomonas maltophilia can present as bacteremia, respiratory tract infection, urinary tract infection, soft tissue and wound infections, bone and joint infections, meningitis, and endocarditis especially in immunosuppressed patients and those with underlying medical conditions. The incidence and impact of S. maltophilia in young children with heart disease are poorly defined. A single center retrospective observational study was conducted in infants <180 days of age with positive S. maltophilia cultures over a period of 5 years. The overall incidence for S. maltophilia infection was 0.8 % (n = 32/3656). Among 32 identified infants, there were 47 episodes of S. maltophilia infection 66 % of infants had prior exposure to broad spectrum antibiotics. 97 % of positive isolates were susceptible to trimethoprim/sulfamethoxazole and 91 % to levofloxacin as well as ticarcillin/clavulanate. Ventilator-free days and absolute lymphocyte count prior to acquiring infection were significantly lower in non-survivors than in survivors. 100 % of survivors had clearance of positive cultures compared to 50 % in non-survivors (p < 0.05). The crude all-cause mortality rate was 37.5 %. All non-survivors had increased length of ICU stay and duration of mechanical ventilation and had delayed clearance of infection and required longer duration of treatment.
- The Impact of spgM, rpfF, rmlA Gene Distribution on Biofilm Formation in Stenotrophomonas maltophilia. [Journal Article]
- PLoS One 2014; 9(10):e108409.
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.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.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.Mutations in spgM and rmlA may be relevant to biofilm formation in the clinical isolates of S. maltophilia.