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Xanthomonas maltophilia [keywords]
- 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.
- Activity of the type I signal peptidase inhibitor MD3 against multidrug-resistant Gram-negative bacteria alone and in combination with colistin. [JOURNAL ARTICLE]
- J Antimicrob Chemother 2014 Aug 18.
Effective treatment of Gram-negative bacterial infections is increasingly challenging due to the spread of multidrug-resistant strains and a lack of new antimicrobials in development. Bacterial type I signal peptidases (SPases) represent a highly conserved and essential target for inhibition by novel compounds. SPases are required for the effective processing of membrane translocated proteins involved in core functions related to metabolism, virulence and resistance. In this study we assessed the biochemical and functional activity of a novel synthetic inhibitor (MD3) of SPases against a wide range of Gram-negative pathogens.The activity and specificity of MD3 for recombinant Pseudomonas aeruginosa SPase (LepB) and a genetically engineered LepB-regulatable strain were investigated. Antimicrobial activity of the compound alone and in combination with outer membrane-permeabilizing agents (sodium hexametaphosphate, colistin) was also determined against a collection of P. aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae and Stenotrophomonas maltophilia isolates.MD3 was found to inactivate the P. aeruginosa LepB protein (IC50 10 μM), resulting in antimicrobial effects potentiated in the presence of colistin. MD3 also demonstrated potent activity against wild-type and multidrug-resistant strains of A. baumannii and S. maltophilia with MICs ranging from 0.5 to 14 mg/L in the presence of subinhibitory concentrations of colistin.MD3 is a novel inhibitor of bacterial SPase in a range of non-fermentative Gram-negative bacteria. The antimicrobial activity is potentiated in combination with colistin and suggests that SPase inhibition warrants further exploration as a basis for future mono or combination therapies.
- Clinical characteristics and risk factors of infections caused by Stenotrophomonas maltophilia in a hospital in northwest China. [Journal Article]
- J Infect Dev Ctries 2014; 8(8):1000-5.
Stenotrophomonas maltophilia infections have recently increased in importance in China, particularly in intensive care units (ICUs). The aim of this study was to investigate the clinical characteristics and risk factors of S. maltophilia infection in ICU of a hospital in northwest China.The characteristics and outcomes of patients with any type of S. maltophilia infection at Shaanxi Provincial People's Hospital, Shaanxi, China, over a two-year period (from July 2011 to June 2013) were studied. S. maltophilia antimicrobial susceptibility was tested with the agar dilution method. The risk factors for all-cause in-hospital mortality were assessed with multivariate logistic regression.Forty patients (median age, 72 years; 77.5% males) with S. maltophilia infection were identified. The main type of infection was lower respiratory tract infection (97.5%); one patient had a bloodstream infection. A total of 97.5% patients were infected with two or more organisms at the same time. The main characteristics of the patients were prolonged use of mechanical ventilation, urethral catheter, and central venous catheter before the infections occurred. The case number of infection was not different in the four seasons. High in vitro sensitivity was observed to minocycline (91.2%), levofloxacin (85.3%), and trimethoprim-sulfamethoxazole (79.4%). Most patients received therapy with a combination of agents. The crude mortality was 50%. By multivariate analysis, low albumin content and hypotension were the independent prognostic factors for mortality.Appropriate antimicrobial treatment had no positive impact on mortality. The impacts of albumin supplements and increasing blood pressure on mortality require further clinical studies.
- Effects of the joint exposure of decabromodiphenyl ether and tetrabromobisphenol A on soil bacterial community structure. [JOURNAL ARTICLE]
- Environ Sci Pollut Res Int 2014 Aug 10.
Decabromodiphenyl ether (BDE209) and tetrabromobisphenol A (TBBPA) are the main contaminants at electronic waste (e-waste) recycling sites (EWRSs), and their potential toxicological effects have received extensive attention. However, the impact on soil microorganism of joint exposure to the two chemicals remains almost unknown. Therefore, indoor incubation tests were performed on control and contaminated soil samples to determine the response of soil bacterial community structure in the joint presence of BDE209 and TBBPA for the first time. The results have demonstrated that the soil bacterial diversity generally declined with increasing BDE209 and TBBPA concentrations and moderate and high doses of both chemicals can cause inhibitory effects. PCR-DGGE analysis indicated that the correlations between Shannon-Weaver index and contaminant concentrations could be well represented by a second-order polynomial model. The combined toxicity of the two chemicals was antagonistic during the first 14 days and then synergistic. Pectobacterium carotovorum, Sinorhizobium fredii HH103, and Stenotrophomonas maltophilia were highly tolerant to joint exposure during the entire incubation period. Moreover, some Staphylococcus strains were enriched after 90 days exposed to TBBPA or low concentrations of BDE209, indicating that they might degrade the two chemicals effectively. The results of these observations have provided some basic understanding of potential ecological effects of joint exposure to BDE209 and TBBPA on soil microorganism at EWRSs.
- Stenotrophomonas maltophilia: an emerging pathogen in dialysis units. [JOURNAL ARTICLE]
- J Med Microbiol 2014 Aug 7.
Abstract Infection is an important cause of morbidity and mortality among patients with end stage renal disease. Stenotrophomonas maltophilia is an unusual yet emerging pathogen in dialysis units. We performed a systematic Pub Med/Medline and Scopus review of peer-reviewed English papers on Stenotrophomonas maltophilia infections among patients undergoing chronic dialysis, with regard to vascular accesses, systemic infections and environment contaminations. Moreover, we suggest a treatment algorithm to preserve the patient and the permanent dialysis catheters.