- Retraction for McCarthy et al., "The Ax21 Protein Is a Cell-Cell Signal That Regulates Virulence in the Nosocomial Pathogen Stenotrophomonas maltophilia". [Retraction of Publication]
- JBJ Bacteriol 2017 May 15; 199(10)
- Antibiotic strategies for eradicating Pseudomonas aeruginosa in people with cystic fibrosis. [Review]
- CDCochrane Database Syst Rev 2017 Apr 25; 4:CD004197
- CONCLUSIONS: We found that nebulised antibiotics, alone or in combination with oral antibiotics, were better than no treatment for early infection with Pseudomonas aeruginosa. Eradication may be sustained for up to two years. There is insufficient evidence to determine whether antibiotic strategies for the eradication of early Pseudomonas aeruginosa decrease mortality or morbidity, improve quality of life, or are associated with adverse effects compared to placebo or standard treatment. Four trials comparing two active treatments have failed to show differences in rates of eradication of Pseudomonas aeruginosa. There have been no published randomised controlled trials that investigate the efficacy of intravenous antibiotics to eradicate Pseudomonas aeruginosa in cystic fibrosis. Overall, there is still insufficient evidence from this review to state which antibiotic strategy should be used for the eradication of early Pseudomonas aeruginosa infection in cystic fibrosis.
- Emergence of Stenotrophomonas maltophilia nosocomial isolates in a Saudi children's hospital. Risk factors and clinical characteristics. [Journal Article]
- SMSaudi Med J 2017; 38(5):521-527
- To describe the clinical characteristics of pediatric patients colonized or infected by Stenotrophomonas maltophilia (S. maltophilia) at a Saudi children's hospital, to identify risk factors associ...
To describe the clinical characteristics of pediatric patients colonized or infected by Stenotrophomonas maltophilia (S. maltophilia) at a Saudi children's hospital, to identify risk factors associated with infection, and to investigate the antimicrobial resistance patterns of this emerging pathogen. Methods: In this cross-sectional observational study, 64 non-duplicating S. maltophilia strains were isolated in Najran Maternity and Children's Hospital, Najran, Saudi Arabia between January 2015 to February 2016. Antimicrobial susceptibility testing was performed using the reference broth microdilution method. Results: In this study, 48 (75%) isolates were identified in true infections and 16 (25%) isolates were considered colonization. The main types of S. maltophilia infection were pneumonia in 22 (45.8%) patients and bloodstream infection in 14 (29.2%) patients. The significant risk factors included exposure to invasive procedure (p=0.02), and presence of acute leukemia as an underlying disease (p=0.02). The most active antimicrobials were trimethoprim/sulfamethoxazole (100% sensitivity) and tigecycline (93.7% sensitivity). Conclusions: Stenotrophomonas maltophilia is an emerging nosocomial pathogen among pediatric patients. Accurate identification and susceptibility testing of this emerging pathogen are crucial for the management of infected patients and prevention of spread of this nosocomial pathogen.
- A novel chromatographic approach to distinguish Gram-positive from Gram-negative bacteria using exogenous volatile organic compound metabolites. [Journal Article]
- JCJ Chromatogr A 2017 Apr 12
- This paper utilized L-alanine aminopeptidase activity as a useful approach to distinguish between Gram-negative and Gram-positive bacteria. This was done using two enzyme substrates, specifically 2-a...
This paper utilized L-alanine aminopeptidase activity as a useful approach to distinguish between Gram-negative and Gram-positive bacteria. This was done using two enzyme substrates, specifically 2-amino-N-phenylpropanamide and 2-amino-N-(4-methylphenyl)propanamide which liberated the volatile compounds aniline and p-toluidine, respectively. Two complementary analytical techniques have been used to identify and quantify the VOCs, specifically static headspace multicapillary column gas chromatography ion mobility spectrometry (SHS-MCC-GC-IMS) and headspace solid phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS). Superior limits of detection were obtained using HS-SPME-GC-MS, typically by a factor of x6 such that the LOD for aniline was 0.02μg/mL and 0.01μg/mL for p-toluidine. In addition, it was also possible to determine indole interference-free by HS-SPME-GC-MS at an LOD of 0.01μg/mL. The approach was applied to a range of selected bacteria: 15 Gram-negative and 7 Gram-positive bacteria. Use of pattern recognition, in the form of Principal Component Analysis, confirmed that it is possible to differentiate between Gram-positive and Gram-negative bacteria using the enzyme generated VOCs, aniline and p-toluidine. The exception was Stenotrophomonas maltophilia which showed negligible VOC concentrations for both aniline and p-toluidine, irrespective of the analytical techniques used and hence was not characteristic of the other Gram-negative bacteria investigated. The developed methodology has the potential to be applied for clinical and food applications.
- Relationship of the CreBC two-component regulatory system and inner membrane protein CreD with swimming motility in Stenotrophomonas maltophilia. [Journal Article]
- PlosPLoS One 2017; 12(4):e0174704
- The CreBC two-component system (TCS) is a conserved regulatory system found in Escherichia coli, Aeromonas spp., Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. In this study, we determined...
The CreBC two-component system (TCS) is a conserved regulatory system found in Escherichia coli, Aeromonas spp., Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. In this study, we determined how CreBC TCS regulates secreted protease activities and swimming motility using creB, creC, and creBC in-frame deletion mutants (KJΔCreB, KJΔCreC, and KJΔBC) of S. maltophilia KJ. Compared to wild-type KJ, KJΔCreB had a comparable secreted protease activity; however, the secreted protease activities were obviously reduced in KJΔCreC and KJΔBC, suggesting that CreC works together with another unidentified response regulator (not CreB) to regulate secreted protease activity. Single gene inactivation of creB or creC resulted in mutants with an enhanced swimming motility, and this phenotype was exacerbated in a double mutant KJΔBC. To elucidate the underlying mechanism responsible for the ΔcreBC-mediated swimming enhancement, flagella morphology observation, RNA-seq based transcriptome assay, qRT-PCR, and membrane integrity and potential assessment were performed. Flagella morphological observation ruled out the possibility that swimming enhancement was due to altered flagella morphology. CreBC inactivation upregulated the expression of creD and flagella-associated genes encoding the basal body- and motor-associated proteins. Furthermore, KJΔBC had an increased membrane susceptibility to Triton X-100 and CreD upregulation in KJΔBC partially alleviated the compromise of membrane integrity. The impact of creBC TCS on bacterial membrane potential was assessed by carbonyl cyanide m-chlorophenyl hydrazine (CCCP50) concentration at which 50% of bacterial swimming is inhibited. CCCP50 of wild-type KJ increased when creBC was deleted, indicating an association between the higher membrane potential of KJΔBC cells and enhanced motility. Upregulation of the basal body- and motor-associated genes of flagella in KJΔBC cells may explain the increased membrane potential. Collectively, inactivation of creBC increased swimming motility through membrane potential increase and creD upregulation in S. maltophilia. The increased membrane potential may supply more energy for flagella propelling and CreD upregulation supports membrane stability, providing a strong membrane for flagellum function.
- In vitro antibacterial activity of MGDG-palmitoyl from Oscillatoria acuminata NTAPC05 against extended-spectrum β-lactamase producers. [Journal Article]
- JAJ Antibiot (Tokyo) 2017 Apr 05
- Extended-spectrum β-lactamase (ESBL)-producing bacteria pose a big challenge in clinical practices, warranting a new therapeutic strategy. In this study, methanol extract of the marine cyanobacterium...
Extended-spectrum β-lactamase (ESBL)-producing bacteria pose a big challenge in clinical practices, warranting a new therapeutic strategy. In this study, methanol extract of the marine cyanobacterium Oscillatoria acuminata NTAPC05 was fractionated under bioassay guidance and the fractions were tested against three well-characterized ESBL-producing bacteria Escherichia coli U655, Stenotrophomonas maltophilia B929 and Enterobacter asburiae B938. Out of the four HPLC fractions, fraction 2 showed bactericidal activity against all the three ESBL producers much more efficiently (MIC 100 μg ml(-1)) than the fourth-generation cephalosporin (MIC >125 μg ml(-1)). The active fraction was subjected to time-kill test at concentrations of 1/2 × MIC, 1 × MIC and 2 × MIC, and the results substantiated the bactericidal property of the fraction against the ESBL producers. Spectral analysis revealed monogalactosyldiacylglycerol containing a palmitoyl (MGDG-palmitoyl), being reported for the first time, as the active fraction, and its bactericidal property against ESBL producers was determined. The active fraction appears to damage the bacterial membrane leading to lysis of the cell, as revealed in confocal laser scanning microscopy (CLSM) analysis, that was confirmed in scanning electron microscopic analysis. Cytotoxicity assay revealed the O. acuminata compound to be safe to a normal cell line HEK293 (human embryonic kidney cell). The in silico analysis of MGDG-palmitoyl revealed two successive H-bonding interactions with Leu198 of TEM1 β-lactamase. Taken together, the MGDG-palmitoyl from O. acuminata NTAPC05 offers potential to develop analogs as a therapeutic for bacteremia caused by ESBL producers.The Journal of Antibiotics advance online publication, 5 April 2017; doi:10.1038/ja.2017.40.
- The impact of carbapenem resistance on clinical deterioration and mortality in patients with liver disease. [Journal Article]
- LILiver Int 2017 Apr 04
- CONCLUSIONS: Patients with advanced liver disease are prone to fatal infections caused by carbapenem-resistant gram-negative bacteria. This article is protected by copyright. All rights reserved.
- Clinical characteristics and prognostic factors of patients with Stenotrophomonas maltophilia infections. [Journal Article]
- JLJ Lab Physicians 2017 Apr-Jun; 9(2):132-135
- CONCLUSIONS: Our findings suggest that Stenotrophomonas can cause various infections irrespective of patient's immune status and irrespective of potential source. Thus, Stenotrophomonas should be thought of as potential pathogen and its isolation should be looked with clinical suspicion.
- STENOTROPHOMONAS MALTOPHILIA ENDOPHTHALMITIS 1 MONTH AFTER INTRAVITREAL AFLIBERCEPT. [Journal Article]
- RCRetin Cases Brief Rep 2017 Mar 29
- CONCLUSIONS: Stenotrophomonas maltophilia is a rare infectious agent associated with intravitreal injection and may present 1 month after treatment.
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- Antimicrobial activity of tigecycline and cefoperazone/sulbactam tested against 18,386 Gram-negative organisms from Europe and the Asia-Pacific region (2013-2014). [Journal Article]
- DMDiagn Microbiol Infect Dis 2017 Mar 06
- A total of 18,386 organisms, including 13,224 Enterobacteriaceae, 3536 Pseudomonas aeruginosa, 1254 Acinetobacter spp., and 372Stenotrophomonas maltophilia were collected from Western Europe (WEU; n=...
A total of 18,386 organisms, including 13,224 Enterobacteriaceae, 3536 Pseudomonas aeruginosa, 1254 Acinetobacter spp., and 372Stenotrophomonas maltophilia were collected from Western Europe (WEU; n=10,021), Eastern Europe (EEU; n=4957), and the Asia-Pacific region (APAC; n=3408 [1052 from China]) in 2013-2014 as part of the SENTRY Antimicrobial Surveillance Program and tested by a reference broth microdilution method for susceptibility against tigecycline, cefoperazone/sulbactam, and comparator agents. Overall, 95.3% of Enterobacteriaceae were susceptible (≤1μg/mL; EUCAST) to tigecycline (MIC50/90, 0.12/1μg/mL) with regional EUCAST susceptibility rates of 94.8-97.8% (98.9-99.6% inhibited at ≤2μg/mL [US FDA]). Among Acinetobacter spp., 66.1% (EEU) and 79.5% (WEU) were inhibited at ≤1μg/mL of tigecycline (94.9% and 97.3% inhibited at ≤2μg/mL; pan-European MIC50/90, 1/2μg/mL). For S. maltophilia, 65.4% (China) to 88.9% (EEU) of the isolates were inhibited at ≤1μg/mL of tigecycline. Cefoperazone/sulbactam inhibited 94.6/83.5/91.5% of Enterobacteriaceae at ≤16μg/mL in WEU/EEU/APAC, respectively.