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Xanthomonas maltophilia [keywords]
- Infections Caused by Stenotrophomonas maltophilia in Recipients of Hematopoietic Stem Cell Transplantation. [Journal Article, Review]
- Front Oncol 2014.:232.
Stenotrophomonas maltophilia (S. maltophilia) is a globally emerging Gram-negative bacillus that is widely spread in environment and hospital equipment. Recently, the incidence of infections caused by this organism has increased, particularly in patients with hematological malignancy and in recipients of hematopoietic stem cell transplantation (HSCT) having neutropenia, mucositis, diarrhea, central venous catheters or graft versus host disease and receiving intensive cytotoxic chemotherapy, immunosuppressive therapy, or broad-spectrum antibiotics. The spectrum of infections in HSCT recipients includes pneumonia, urinary tract and surgical site infection, peritonitis, bacteremia, septic shock, and infection of indwelling medical devices. The organism exhibits intrinsic resistance to many classes of antibiotics including carbapenems, aminoglycosides, most of the third-generation cephalosporins, and other β-lactams. Despite the increasingly reported drug resistance, trimethoprim-sulfamethoxazole is still the drug of choice. However, the organism is still susceptible to ticarcillin-clavulanic acid, tigecycline, fluoroquinolones, polymyxin-B, and rifampicin. Genetic factors play a significant role not only in evolution of drug resistance but also in virulence of the organism. The outcome of patients having S. maltophilia infections can be improved by: using various combinations of novel therapeutic agents and aerosolized aminoglycosides or colistin, prompt administration of in vitro active antibiotics, removal of possible sources of infection such as infected indwelling intravascular catheters, and application of strict infection control measures.
- High-dosage tigecycline for Stenotrophomonas maltophilia bacteremia. [Journal Article]
- Chin Med J (Engl) 2014 Sep; 127(17):3199.
- Preventing microbial colonisation of catheters: Antimicrobial and antibiofilm activities of cellobiose dehydrogenase. [JOURNAL ARTICLE]
- Int J Antimicrob Agents 2014 Aug 4.
The ability of cellobiose dehydrogenase (CDH) to produce hydrogen peroxide (H2O2) for antimicrobial and antibiofilm functionalisation of urinary catheters was investigated. A recombinantly produced CDH from Myriococcum thermophilum was shown to completely inhibit the growth of Escherichia coli and Staphylococcus aureus both in liquid and solid media when supplemented with either 0.8mM or 2mM cellobiose as substrate. Biofilm formation on silicone films was prevented by CDH when supplemented with 1mM cellobiose. The CDH/cellobiose system also successfully inhibited many common urinary catheter-colonising micro-organisms, including multidrug-resistant S. aureus, Staphylococcus epidermidis, Proteus mirabilis, Stenotrophomonas maltophilia, Acinetobacter baumannii and Pseudomonas aeruginosa. Interestingly, CDH was also able to produce H2O2 during oxidation of extracellular polysaccharides (exPS) formed by micro-organisms in the absence of cellobiose. The H2O2 production and consequently antimicrobial and antibiofilm activities on these exPS were enhanced by incorporation of glycoside hydrolases such as amylases. Hydrolysis of polysaccharides by these enzymes increases the number of terminal reducing sugars as substrates for CDH as well as destabilises the biofilm. Furthermore, CDH suspended in catheter lubricants killed bacteria in biofilms colonising catheters. Incorporation of the CDH/cellobiose system in the lubricant therefore makes it an easy strategy for preventing microbial colonisation of catheters.
- Prevalence and Features of Pathogenic Bacteria in the Department of Hematology without Bone Marrow Transplantation in Peking Union Medical College Hospital from 2010 to 2012. [Journal Article]
- Zhongguo Yi Xue Ke Xue Yuan Xue Bao 2014 Aug 31; 36(4):439-45.
Objective To investigate the incidence,pathogens,and clinical features of infection in consecutive cases from 2010 to 2012 in Peking Union Medical College Hospital. Method The incidence,pathogen,treatment,and outcomes of patients with hematological diseases who had positive findings of bacterium in their samples from 2010 to 2012 were retrospectively analyzed. Results There were 449 positive samples (5.8%) from 4 890 patients during this period,among which 388 were proved to be with pathogenic bacteria. Samples separated from patients with community-aquired infections accounted for 8.4% of all positive samples. Most community-aquired infections were caused by Gram-negative bacteria (75%),although no multidrug-resistant bacteria was observed. Samples separated from patients with nosocomial infections accounted for 91.6% of all positive samples. Respiratory tract (49.4%) and peripheral blood (32.6%) were the most common samples with positive results. Skin soft tissues (10.4%),and urine (3.7%) were less common samples. Most of the pathogenic bacteria of the nosocomial infections were Gram-negative (66.9%). The most common Gram-negative bacteria included Escherichia coli (13.8%),Pseudomonas aeruginosa (12.1%),and Klebsiella pneumonia (12.1%),while Staphylococcus aureus (10.4%),Enterococcus faecium (7.0%),and Staphylococcus epidermidis (5.1%) were the most common Gram-positive bacteria. Gram-negative bacteria consisted of most of sputum samples and peripheral blood samples. Samples from the surface of skin wound and anal swab were composed largely by Gram-positive bacteria (63.8%). The detection rates of extended-spectrum beta-lactamase-producing Klebsiella pneumonia/Klebsiella oxytoca,Escherichia coli,and Proteus mirabilis were 24.0%,87.9% and 38.4%,respectively. The resistance to Acinetobacter baumannii was serious. Multidrug-resistant,extensive drug resistant and pan drug resistant A. baumannii acountted for 74% of all A. Baumannii infections. Stenotrophomonas maltophilia showed low resistance to sulfamethoxazole/trimethoprim,levofloxacin and minocycline. Also,22 methicillin-resistant Staphylococcus aureus and 9 methicillin-resistant Staphylococcus Epidermidis were detected,which were only sensitive to vancomycin,teicoplanin,and linezolid. All patients were treated in the haematology wards and most of them were under agranulocytosis or immunosuppression. Finally,22 patients reached clinical recovery through anti-infective therapy,whereas 49 patients died. Among those deaths,42 patients attributed to severe infections and infection-associated complications. Fourteen of all the deaths might be infected with drug-resistance bacteria. There were 61 samples proved to be bacteria colonization. Nonfermenters such as Acinetobacter baumannii and Stenotrophomonas maltophilia made up for a large amount of bacteria colonization. Conclusions The pathogens of nosocomial infections in the hematology ward are mainly Gram-negative bacteria. The incidences and pathogens vary from different infection sites. Nosocomial infection still has a higher mortality rate. Once nonfermenters are detected positive,the pathogenic or colonial bacteria should be distinguished.
- Non-fermentative gram-negative bacteria in hospital tap water and water used for haemodialysis and bronchoscope flushing: Prevalence and distribution of antibiotic resistant strains. [JOURNAL ARTICLE]
- Sci Total Environ 2014 Aug 28.:47-54.
This study provides a detailed description of the distribution of non-fermentative gram-negative bacteria (NFGNB) collected in water sources (tap water and water used for haemodialysis and bronchoscope flushing) from different wards of a tertiary care hospital. The aim is to identify risk practices for patients or to alert clinicians to the possible contamination of environment and medical devices. The resistance profile of NFGNB environmental isolates has shown that more than half (55.56%) of the strains isolated were resistant to one or more antibiotics tested in different antimicrobial categories. In particular, 38.89% of these strains were multidrug resistant (MDR) and 16.67% were extensively drug resistant (XDR). The most prevalent bacterial species recovered in water samples were Pseudomonas aeruginosa, Pseudomonas fluorescens, Ralstonia pickettii and Stenotrophomonas maltophilia. Analysis of antibiotic resistance rates has shown remarkable differences between Pseudomonadaceae (P. aeruginosa and P. fluorescens) and emerging pathogens, such as S. maltophilia and R. pickettii. Multidrug resistance can be relatively common among nosocomial isolates of P. aeruginosa, which represent the large majority of clinical isolates; moreover, our findings highlight that the emergent antibiotic resistant opportunistic pathogens, such as R. pickettii and S. maltophilia, isolated from hospital environments could be potentially more dangerous than other more known waterborne pathogens, if not subjected to surveillance to direct the decontamination procedures.
- Stenotrophomonas maltophilia endogenous endophthalmitis: clinical presentation, antibiotic susceptibility, and outcomes. [Journal Article]
- Clin Ophthalmol 2014.:1523-6.
To describe clinical presentation, antibiotic susceptibility, and outcomes in patients with Stenotrophomonas maltophilia endogenous endophthalmitis.Retrospective case series.Four eyes of four patients with S. maltophilia endogenous endophthalmitis.Retrospective chart review of culture-positive S. maltophilia endogenous endophthalmitis treated at L V Prasad Eye Institute, Hyderabad, India, between January 2007 and December 2012, was done. Collected information included demographic, clinical, and microbiology data.These four patients with S. maltophilia endogenous endophthalmitis cases accounted for 0.47% (4/836) of total bacterial endophthalmitis cases treated in this period. All patients were from a rural setting and younger than 40 years. Two of the four patients had a history of immune compromise or hospitalization. The visual acuity at presentation was less than 20/320 in all patients. Common presenting features were severe anterior and posterior segment inflammation and hypopyon. All patients underwent vitrectomy with injection of intravitreal antibiotics and dexamethasone. Direct microscopy of the vitreous sample was positive in all cases. All isolates were sensitive to fluoroquinolones and chloramphenicol; sensitivity to aminoglycosides and third-generation cephalosporins was highly variable. The final visual acuity was 20/80 or more in three patients. The time to presentation did not seem to influence the visual or anatomical outcome.S. maltophilia is a rare cause of endogenous endophthalmitis and usually occurs in young and apparently healthy individuals. Clinical presentation is moderate to severe, and recovery is variable. Fourth-generation fluoroquinolones and chloramphenicol were the most sensitive antibiotics against S. maltophilia in this series of patients.
- Stenotrophomonas maltophilia in Mexico: antimicrobial resistance, biofilm formation, and clonal diversity. [JOURNAL ARTICLE]
- J Med Microbiol 2014 Aug 27.
Stenotrophomonas maltophilia is an important multidrug-resistant nosocomial pathogen associated with high mortality. Our aim is to examine antimicrobial susceptibility, biofilm production, and clonal relatedness of clinical isolates of S. maltophilia. S. maltophilia isolates were collected between 2006 and 2013 from two tertiary-care hospitals in Mexico. Antimicrobial susceptibility was evaluated by the broth microdilution method. PCR was used to determine the presence of β-lactamase genes L1 and L2. Biofilm formation was assessed with crystal violet staining. Clonal relatedness was determined by pulsed-field gel electrophoresis (PFGE). Among the 119 collected S. maltophilia isolates, 73 (61.3%) were from the respiratory tract. Resistance levels exceeded 75% for imipenem, meropenem, ampicillin, aztreonam, gentamicin, and tobramycin. Resistance to trimethoprim-sulfamethoxazole was 32.8%. L1 and L2 genes were detected in 77.1% (91/118) and 66.9% (79/118) of isolates, respectively. All S. maltophilia strains were able to produce biofilms. Strains were classified as weak (47.9%, 57/119), moderate (38.7%, 46/119), or strong (13.4%, 16/119) biofilm producers. A total of 89 distinct PFGE types were identified, and 21.6% (22/102) of the isolates were distributed in nine clusters. This is the first study in Mexico to reveal characteristics of clinical isolates of S. maltophilia. Clonal diversity data indicate low cross-transmission of S. maltophilia in a hospital setting. The high antibiotic resistance underscores the need for continuous surveillance of S. maltophilia in hospital settings in Mexico.
- [Isolation and characterization of two bacteria with heavy metal resistance and phosphate solubilizing capability]. [English Abstract, Journal Article]
- Huan Jing Ke Xue 2014 Jun; 35(6):2334-40.
Two phosphate solubilizing bacteria (T PSB1 and T PSB 2) with high heavy metal resistance were isolated from soil of a lead-zinc mine in Huayuan of Hunan Province, China. These two bacteria were identified as Stenotrophomonas maltophilia and Burkholderia gladioli by 16S rRNA sequencing analysis, respectively. In the media containing insoluble inorganic calcium phosphate, the soluble phosphate amounts reached respectively 402.9 mg x L(-1) and 589.9 mg x L(-1) with the bacteria T PSB1 and T PSB2 after two weeks' growth. Moreover, the two bacteria developed solubilizing halos on the plates supplemented with the organic phosphate compounds, and the resulting soluble phosphate amounts in the broth media were respectively 2.97 mg x L(-1) and 4.69 mg x L(-1). In addition, these two bacteria showed the resistance to up to 2000 mg x L(-1) Zn2+, and their phosphate solubilizing amounts reached respectively 114.8 mg x L(-1) and 125.1 mg x L(-1). Similarly, their heavy metal resistance and phosphate solubilizing ability were also found in the Cr and Pb broth media with the concentration of 1000 mg x L(-1). In the Pb media, the soluble phosphate amounts reached respectively 57.9 mg x L(-1) and 71.7 mg x L(-1), and the soluble P amounts in the Cr media were 60.1 mg x L(-1) and 98.4 mg x L(-1) at the concentration of 1000 mg x L(-1).
- [Pathogenic analysis of ventilator-associated pneumonia in the pediatric intensive care unit in high-altitude areas.] [JOURNAL ARTICLE]
- Zhongguo Dang Dai Er Ke Za Zhi 2014 Aug; 16(8):787-790.
To investigate the pathogens of ventilator-associated pneumonia (VAP) and their drug resistance in the pediatric intensive care unit (PICU) in high-altitude areas and to provide a clinical basis for the prevention and treatment of VAP.A total of 94 children with VAP hospitalized in the PICU in high-altitude areas between June 2011 and June 2013 were recruited. Their lower respiratory tract secretions were collected for bacterial culture and drug sensitivity test.Of the 94 children with VAP, 22 (23%) had a single bacterial infection, and 72 (77%) had mixed infections, mostly with Klebsiella pneumoniae and Acinetobacter baumannii (17 cases, 27%). Of the 178 isolated strains of pathogens, 139 (78%) were Gram-negative bacteria (G(-) bacteria), mainly including Klebsiella pneumoniae, Stenotrophomonas maltophilia, Acinetobacter baumannii, and Pseudomonas aeruginosa, 26 (15%) were Gram-positive bacteria (G(+) bacteria), mainly including Staphylococcus aureus, and 13 (7%) were fungi, mainly including Candida albicans. Most G(-) bacteria had a high drug resistance. Pseudomonas aeruginosa was extensively drug-resistant. Acinetobacter baumannii was only highly sensitive to cefoperazone/sulbactam and imipenem. Multidrug resistance (methicillin resistance) was found in G+ bacteria, for which vancomycin was effective.The pathogens of VAP in high-altitude areas are mostly G- bacteria, which may cause mixed infections and develop drug resistance. This provides guidance for the rational use of antimicrobial drugs and the development of key prevention and control measures for VAP.
- MacABCsm, an ABC-type tripartite efflux pump of Stenotrophomonas maltophilia involved in drug resistance, oxidative and envelope stress tolerances and biofilm formation. [JOURNAL ARTICLE]
- J Antimicrob Chemother 2014 Aug 19.
To characterize a five gene cluster, macRS-macABCsm, in Stenotrophomonas maltophilia.The presence of macABCsm operon was verified by RT-PCR. The substrate spectrum of the MacABCsm efflux pump was investigated by mutant construction and susceptibility testing. The physiological role of MacABCsm was assessed by comparing the growth of wild-type and macABCsm mutant under different stresses. To examine the regulatory role of the two-component regulatory system (TCS) macRS in the expression of macABCsm operon, mutant construction, quantitative RT-PCR and susceptibility testing were employed.macAsm, macBsm and macCsm genes formed a three-membered operon. The MacABCsm efflux pump extruded macrolides, aminoglycosides and polymyxins and contributed to oxidative and envelope stress tolerances and biofilm formation. Inactivation of macRS TCS hardly influenced the expression of macABCsm operon and the antimicrobial susceptibility.The MacABCsm pump has physiological roles in protecting S. maltophilia from the attack of oxidative and envelope stresses and in biofilm formation, which may be the reason why it can be constitutively expressed in the absence of antibiotics and is highly conserved in S. maltophilia isolates isolated from different environmental niches. However, the constitutive expression of macABCsm contributes to the intrinsic resistance of S. maltophilia to macrolides, aminoglycosides and polymyxins.