- Global and local selection acting on the pathogen Stenotrophomonas maltophilia in the human lung. [Journal Article]
- NCNat Commun 2017 Jan 19; 8:14078
- Bacterial populations diversify during infection into distinct subpopulations that coexist within the human body. Yet, it is unknown to what extent subpopulations adapt to location-specific selective...
Bacterial populations diversify during infection into distinct subpopulations that coexist within the human body. Yet, it is unknown to what extent subpopulations adapt to location-specific selective pressures as they migrate and evolve across space. Here we identify bacterial genes under local and global selection by testing for spatial co-occurrence of adaptive mutations. We sequence 552 genomes of the pathogen Stenotrophomonas maltophilia across 23 sites of the lungs from a patient with cystic fibrosis. We show that although genetically close isolates colocalize in space, distant lineages with distinct phenotypes separated by adaptive mutations spread throughout the lung, suggesting global selective pressures. Yet, for one gene (a distant homologue of the merC gene implicated in metal resistance), mutations arising independently in two lineages colocalize in space, providing evidence for location-specific selection. Our work presents a general framework for understanding how selection acts upon a pathogen that colonizes and evolves across the complex environment of the human body.
- Nosocomial Infections with IMP-19-Producing Pseudomonas aeruginosa Linked to Contaminated Sinks, France. [Journal Article]
- EIEmerg Infect Dis 2017; 23(2):304-307
- We isolated IMP-19-producing Pseudomonas aeruginosa from 7 patients with nosocomial infections linked to contaminated sinks in France. We showed that blaIMP-19 was located on various class 1 integron...
We isolated IMP-19-producing Pseudomonas aeruginosa from 7 patients with nosocomial infections linked to contaminated sinks in France. We showed that blaIMP-19 was located on various class 1 integrons among 8 species of gram-negative bacilli detected in sinks: P. aeruginosa, Achromobacter xylosoxidans, A. aegrifaciens, P. putida, Stenotrophomonas maltophilia, P. mendocina, Comamonas testosteroni, and Sphingomonas sp.
- In vitro activity of ceftolozane-tazobactam against multidrug-resistant non-fermenting Gram-negative bacilli isolated from patients with cystic fibrosis. [Journal Article]
- AAAntimicrob Agents Chemother 2017 Jan 17
- Ceftolozane-tazobactam was tested against 58 multidrug-resistant non-fermenting Gram-negative bacilli (35 Pseudomonas aeruginosa, 11 Achromobacter xylosoxydans and 12 Stenotrophomonas maltophilia) is...
Ceftolozane-tazobactam was tested against 58 multidrug-resistant non-fermenting Gram-negative bacilli (35 Pseudomonas aeruginosa, 11 Achromobacter xylosoxydans and 12 Stenotrophomonas maltophilia) isolated from cystic fibrosis patients and compared to ceftolozane alone, ceftazidime, meropenem and piperacillin-tazobactam. Ceftolozane-tazobactam was the most active agent against P. aeruginosa but was inactive against A. xylosoxydans and S. maltophilia In time-kill experiments ceftolozane-tazobactam had complete bactericidal activity against 2/6 (33%) clinical isolates.
- Clinical Characteristics of Stenotrophomonas maltophilia Bacteremia: A Regional Report and a Review of a Japanese Case Series. [Journal Article]
- IMIntern Med 2017; 56(2):137-142
- Objective Stenotrophomonas maltophilia is an emerging nosocomial pathogen that causes fatal infections in critically ill or immunocompromised patients. S. maltophilia bacteremia (SMB) is a rare condi...
Objective Stenotrophomonas maltophilia is an emerging nosocomial pathogen that causes fatal infections in critically ill or immunocompromised patients. S. maltophilia bacteremia (SMB) is a rare condition, and its clinical characteristics in Japanese settings are not well known. Methods The medical charts of patients with SMB were retrospectively reviewed at two medical facilities (Okayama University Hospital and Tsuyama Chuo Hospital) for seven years. The data were analyzed along with those previously reported from other Japanese facilities. Result A total of 181 patients (110 men and 71 women) were evaluated. The major underlying diseases included hematologic malignancy (36.5%), solid organ malignancy (25.4%), and neutropenia (31.5%). The recent use of carbapenem was seen in 56.9% of the cases in total, and more than one-third of the patients in our hospitals were treated with carbapenem at the onset of SMB. Of 28 (63.6%) of 44 cases treated for S. maltophilia, those who did not survive were more likely to have been treated with broad-spectrum antibiotics. A multivariate analysis revealed that a higher updated Charlson Comorbidity Index [odds ratio (95% confidence interval), 1.75 (1.11-2.75); p=0.015] and intubation [odds ratio (95% confidence interval), 12.6 (1.62-97.9); p=0.016] were associated with mortality in our cases. Pathogens were often resistant to ceftazidime but susceptible to minocycline, trimethoprim/sulfamethoxazole, and fluoroquinolones. The overall mortality rates within 30 and 90 days were 37.5% and 62.5%, respectively. Conclusion The clinical characteristics of SMB in Japanese cases were similar to those reported from other countries. Clinicians should be aware that breakthrough infection by S. maltophilia may occur during administration of carbapenem.
- Current Situation of Antimicrobial Resistance and Genetic Differences in Stenotrophomonas maltophilia Complex Isolates by Multilocus Variable Number of Tandem Repeat Analysis. [Journal Article]
- ICInfect Chemother 2016; 48(4):285-293
- CONCLUSIONS: Because of high resistance rates to TMP/SMX and levofloxacin, the clinical laboratory department should consider providing the data about other antimicrobial agents and treatment of S. maltophilia infections with a combination of antimicrobials can be considered in the current practice. The MLVA evaluated in this study provides a fast, portable, relatively low cost genotyping method that can be employed in genotypic linkage or transmission networks comparing to analysis of the gyrB gene.
- Identification of Electrode Respiring, Hydrocarbonoclastic Bacterial Strain Stenotrophomonas maltophilia MK2 Highlights the Untapped Potential for Environmental Bioremediation. [Journal Article]
- FMFront Microbiol 2016; 7:1965
- Electrode respiring bacteria (ERB) possess a great potential for many biotechnological applications such as microbial electrochemical remediation systems (MERS) because of their exoelectrogenic capab...
Electrode respiring bacteria (ERB) possess a great potential for many biotechnological applications such as microbial electrochemical remediation systems (MERS) because of their exoelectrogenic capabilities to degrade xenobiotic pollutants. Very few ERB have been isolated from MERS, those exhibited a bioremediation potential toward organic contaminants. Here we report once such bacterial strain, Stenotrophomonas maltophilia MK2, a facultative anaerobic bacterium isolated from a hydrocarbon fed MERS, showed a potent hydrocarbonoclastic behavior under aerobic and anaerobic environments. Distinct properties of the strain MK2 were anaerobic fermentation of the amino acids, electrode respiration, anaerobic nitrate reduction and the ability to metabolize n-alkane components (C8-C36) of petroleum hydrocarbons (PH) including the biomarkers, pristine and phytane. The characteristic of diazoic dye decolorization was used as a criterion for pre-screening the possible electrochemically active microbial candidates. Bioelectricity generation with concomitant dye decolorization in MERS showed that the strain is electrochemically active. In acetate fed microbial fuel cells (MFCs), maximum current density of 273 ± 8 mA/m(2) (1000 Ω) was produced (power density 113 ± 7 mW/m(2)) by strain MK2 with a coulombic efficiency of 34.8%. Further, the presence of possible alkane hydroxylase genes (alkB and rubA) in the strain MK2 indicated that the genes involved in hydrocarbon degradation are of diverse origin. Such observations demonstrated the potential of facultative hydrocarbon degradation in contaminated environments. Identification of such a novel petrochemical hydrocarbon degrading ERB is likely to offer a new route to the sustainable bioremedial process of source zone contamination with simultaneous energy generation through MERS.
- Genome Shuffling of Stenotrophomonas maltophilia OK-5 for Improving the Degradation of Explosive RDX (Hexahydro-1,3,5-trinitro-1,3,5-triazine). [Journal Article]
- CMCurr Microbiol 2016 Dec 22
- A genome-shuffled Stenotrophomonas maltophilia strain showing the enhanced ability of RDX degradation was constructed, and its characteristics were compared with those of the wild-type one. The shuff...
A genome-shuffled Stenotrophomonas maltophilia strain showing the enhanced ability of RDX degradation was constructed, and its characteristics were compared with those of the wild-type one. The shuffled strain was able to completely degrade 25, 50, and 75 µM RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) within 10, 30, and 50 days, respectively. However, it took 30 and 70 days for the wild-type strain to degrade 25 and 50 µM RDX, respectively, and at day 70, the strain degraded only 67% of 75 µM RDX. The shuffled strain reached its maximum growth at 50-60 days and exhibited approximately 1.5-fold increased cell numbers. SEM revealed more severe damage on the surface of the wild-type cells compared to the genome-shuffled cells. The mRNA levels of dnaK and groEL encoding the heat shock proteins were increased by 2.5-fold and fourfold, and DnaK and GroEL proteins were more highly produced in the shuffled cells. In addition, the mRNA levels of pnrB encoding a TNT nitroreductase, and algA involved in exopolymer biosynthesis, were slightly higher in the shuffled strain, but not as high as those of dnaK and groEL. These results indicate that the genome shuffling rendered the shuffled cells more resistant to RDX stress. A proteomic comparison revealed changes in the production levels of certain proteins including nitrate and cell protection, particularly those involved in metabolism. These proteomic analyses provide clues for understanding the improved RDX degradation by the genome-shuffled S. maltophilia strain.
- Colonization pressure as a risk factor of ICU-acquired multidrug resistant bacteria: a prospective observational study. [Journal Article]
- EJEur J Clin Microbiol Infect Dis 2016 Dec 20
- The primary objective of this study was to evaluate the impact of colonization pressure on intensive care unit (ICU)-acquired multidrug resistant bacteria (MDRB). All patients hospitalized for more t...
The primary objective of this study was to evaluate the impact of colonization pressure on intensive care unit (ICU)-acquired multidrug resistant bacteria (MDRB). All patients hospitalized for more than 48 h in the ICU were included in this prospective observational study. MDRB were defined as methicillin resistant Staphylococcus aureus, Pseudomonas aeruginosa resistant to ceftazidime or imipenem, Gram-negative bacilli producing extended-spectrum beta-lactamases (ESBL), and all strains of Acinetobacter baumannii and Stenotrophomonas maltophilia. Colonization pressure was daily calculated in the three participating ICUs. Univariate and multivariate analyses were used to determine risk factors for ICU-acquired MDRB. Two hundreds and four (34%) of the 593 included patients acquired an MDRB during their ICU stay. Multivariate analysis identified colonization pressure as an independent risk factor for ICU-acquired MDRB (OR (95% CI) 4.18 (1.03-17.01), p = 0.046). Other independent risk factors for ICU-acquired MDRB were mechanical ventilation (3.08 (1.28-7.38), p = 0.012), and arterial catheter use (OR, 3.04 (1.38-6.68), p = 0.006). ICU-acquired MDRB were associated with increased mortality, duration of mechanical ventilation, and ICU stay. However, ICU-acquired MDRB was not independently associated with ICU-mortality. Colonization pressure is an independent risk factor for acquiring MDRB in the ICU.
- Intravenous Colistin Use for Multidrug-Resistant Gram-Negative Infections in Pediatric Patients. [Journal Article]
- BMBalkan Med J 2016; 33(6):627-632
- CONCLUSIONS: Colistin appears to be a safe and efficacious drug for treating MDR-GNB infections in children.
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- Emerging Trends of Bloodstream Infections: A Six-Year Study at a Paediatric Tertiary Care Hospital in Kabul. [Journal Article]
- JCJ Coll Physicians Surg Pak 2016; 26(11):887-891
- CONCLUSIONS: Staphylococci and Klebsiellae remain the most important bacteria responsible for bloodstream infections in a tertiary healthcare facility in Kabul. Yet, there has been an increase in the prevalence of Pseudomonas and Burkholderia cepacia. Moreover, Stenotrophomonas maltophilia emerged as a new hospital acquired pathogen. This study could possibly help in suggesting choices eluding the misuse of appropriate antibiotics.