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Xanthomonas maltophilia [keywords]
- Susceptibility of Stenotrophomonas maltophilia clinical strains in China to antimicrobial combinations. [JOURNAL ARTICLE]
- J Chemother 2014 Mar 4.:1973947814Y0000000168.
We aimed to investigate the activity levels of several combinations of antimicrobials against Stenotrophomonas maltophilia. In this study, the antimicrobial susceptibility of S. maltophilia clinical isolates was determined, and the synergistic activity of three pairs of antimicrobial combinations was evaluated by the fractional inhibitory concentration index (FICI). The antimicrobial susceptibility in vitro against 83 S. maltophilia strains was greater for minocycline (80·7%) than for trimethoprim-sulfamethoxazole (51·8%), and levofloxacin (50·6%). The rate of resistance was highest for ticarcillin-clavulanate and ceftazidime (63·8%) and resistance to trimethoprim-sulfamethoxazole (TMP-SMX) was 48·2%. All three combinations were tested against susceptible isolates. Two of the combinations, TMP-SMX+ceftazidime and levofloxacin+ceftazidime were more effective than the combination of TMP-SMX+levofloxacin. We recommend acquiring more clinical data in order to explore combination therapy, which is a promising treatment of S. maltophilia infections.
- Stenotrophomonas maltophilia Virulence and Specific Variations in Trace Elements during Acute Lung Infection: Implications in Cystic Fibrosis. [Journal Article]
- PLoS One 2014; 9(2):e88769.
Metal ions are necessary for the proper functioning of the immune system, and, therefore, they might have a significant influence on the interaction between bacteria and host. Ionic dyshomeostasis has been recently observed also in cystic fibrosis (CF) patients, whose respiratory tract is frequently colonized by Stenotrophomonas maltophilia. For the first time, here we used an inductively mass spectrometry method to perform a spatial and temporal analysis of the pattern of changes in a broad range of major trace elements in response to pulmonary infection by S. maltophilia. To this, DBA/2 mouse lungs were comparatively infected by a CF strain and by an environmental one. Our results showed that pulmonary ionomic profile was significantly affected during infection. Infected mice showed increased lung levels of Mg, P, S, K, Zn, Se, and Rb. To the contrary, Mn, Fe, Co, and Cu levels resulted significantly decreased. Changes of element concentrations were correlated with pulmonary bacterial load and markers of inflammation, and occurred mostly on day 3 post-exposure, when severity of infection culminated. Interestingly, CF strain - significantly more virulent than the environmental one in our murine model - provoked a more significant impact in perturbing pulmonary metal homeostasis. Particularly, exposure to CF strain exclusively increased P and K levels, while decreased Fe and Mn ones. Overall, our data clearly indicate that S. maltophilia modulates pulmonary metal balance in a concerted and virulence-dependent manner highlighting the potential role of the element dyshomeostasis during the progression of S. maltophilia infection, probably exacerbating the harmful effects of the loss of CF transmembrane conductance regulator function. Further investigations are required to understand the biological significance of these alterations and to confirm they are specifically caused by S. maltophilia.
- In vitro activity of tigecycline against isolates collected from complicated skin and skin structure infections and intra-abdominal infections in Africa and Middle East countries: TEST 2007-2012. [JOURNAL ARTICLE]
- Diagn Microbiol Infect Dis 2014 Jan 30.
Complicated skin and skin structure infections (cSSSIs) and intra-abdominal infections (IAIs) are problematic due to decreasing therapeutic options available against multidrug-resistant pathogens common among these types of infections. A total of 2245 isolates from African and the Middle Eastern (AfME) countries were collected to determine in vitro activity for tigecycline and comparators during 2007-2012 as part of the Tigecycline Evaluation Surveillance Trial program. Tigecycline was launched in the AfME in 2007 and remains active against a wide range of targeted pathogens worldwide. Isolates were recovered from cSSSI (1990) and IAI (255) from 38 sites in 11 AfME countries. Staphylococcus aureus was the most common species from cSSSI (27.9%), and the methicillin-resistant S. aureus rate was 25%. Enterococcus spp. (7.1%) and Streptococcus agalactiae (2.9%) were other common Gram-positive pathogens represented. Enterobacter spp. (14.5%), Pseudomonas aeruginosa (13.9%), Escherichia coli (11.4%), Klebsiella spp. (10.9%), and Acinetobacter spp. (7.2 %) were the most common Gram-negative species collected. Tigecycline MIC90 values were 0.25 μg/mL against S. aureus. E. coli and Enterobacter spp. had tigecycline MIC90 values of 1 and 2 μg/mL, respectively. E. coli was the most frequently collected species from IAI (28.3%), followed by Klebsiella spp. (20.8%), Enterococcus spp. (11.8%), and Stenotrophomonas maltophilia (6.3%). Isolates collected from IAI had the following tigecycline MIC90 values: E. coli (1 μg/mL), Klebsiella spp. and other Enterobacteriaceae (2 μg/mL), Enterococcus spp. (0.25 μg/mL), and S. maltophilia (1 μg/mL). Tigecycline in vitro activity was observed against a broad spectrum of bacterial species, including strains resistant to other antimicrobial classes.
- Antimicrobial-resistant Gram-negative bacteria in febrile neutropenic patients with cancer: current epidemiology and clinical impact. [Journal Article]
- Curr Opin Infect Dis 2014 Apr; 27(2):200-10.
In the recent years, several studies involving cancer patients have demonstrated a clear trend in the epidemiology of bacterial infections showing a shift in the prevalence from Gram-positive to Gram-negative bacteria and the extensive emergence of antimicrobial-resistant strains among Gram-negatives isolated from the blood. The aim of this systematic review was to examine the recent trends in epidemiology and antimicrobial resistance in Gram-negatives recovered from neutropenic cancer patients, with particular emphasis on the impact of antimicrobial resistance on the clinical outcome of severe infections caused by such microorganisms.Overall, from 2007 to date, the rate of Gram-negative bacteria recovery ranged from 24.7 to 75.8% (mean 51.3%) in cancer patient cohorts. Escherichia coli represented the most common species (mean frequency of isolation 32.1%) among the Gram-negatives, followed by Pseudomonas aeruginosa (mean frequency of isolation 20.1%). An increasing frequency of Acinetobacter spp. and Stenotrophomonas maltophilia was also reported. Increased rates of multidrug-resistant Gram-negative strains have been highlighted among Enterobacteriaceae and nonfermenting Gram-negative rods, despite discontinuation of fluoroquinolone-based antibacterial prophylaxis for neutropenic patients. In addition, antimicrobial resistance and/or the inadequacy of empirical antibiotic treatment have been frequently linked to a worse outcome in cancer patients with bloodstream infections caused by Gram-negative isolates.Sound knowledge of the local distribution of pathogens and their susceptibility patterns and prompt initiation of effective antimicrobial treatment for severe infections caused by Gram-negative bacteria are essential in cancer patients.
- Life-threatening hemorrhagic pneumonia caused by Stenotrophomonas maltophilia in the treatment of hematologic diseases. [JOURNAL ARTICLE]
- Ann Hematol 2014 Feb 18.
Since the late 1990s, Stenotrophomonas maltophilia (S. maltophilia) has become one of the most common nonfermenting Gram-negative bacilli that cause opportunistic infection. Patients with hematologic diseases are the most risky candidate for S. maltophilia pneumonia or sepsis because of chemotherapy-induced neutropenia or immunodeficiency. Frequent exposure to broad-spectrum antibiotics and prolonged insertion of central venous catheter further enhance the risk of S. maltophilia infection. One of the most severe S. maltophilia infections is hemorrhagic pneumonia. This type of infection is mostly fatal because of pulmonary alveolar hemorrhage that leads to acute respiratory failure. Furthermore, S. maltophilia exhibits a high-level intrinsic resistance to conventional antibiotics such as β-lactams and aminoglycosides and, more recently, the increasing acquired resistance to co-trimoxazole and quinolones. According to our experienced and previously reported cases, all of the patients with hemorrhagic pneumonia caused by S. maltophilia had a fatal course within a few days after the onset of the pneumonia. In this article, we perform a systematic review on a total 30 cases of hemorrhagic pneumonia induced by S. maltophilia from our institutions and the literature, and we describe its early diagnosis, prophylaxis, and recommended therapeutic strategy for the infection in the treatment of hematologic disease.
- Virulence genes in clinical and environmental Stenotrophomas maltophilia isolates: A genome sequencing and gene expression approach. [JOURNAL ARTICLE]
- Microb Pathog 2014 Feb 14.
The rate of nosocomial infections with the opportunistic pathogen Stenotrophomonas maltophilia has remarkably increased in the last decade. To determine S. maltophilia virulence genes, the complete genome sequences of two S. maltophilia isolates were compared. The clinical strain SKK35 was proved virulent in an amoeba host-pathogen model, and wastewater strain RA8 was determined as non-virulent in the amoeba model. The genome sequences of three additional S. maltophilia strains, K279a (virulent against amoeba), R511-3 and SKA14 (both non-virulent against amoeba) were taken into account as reference strains. We were able to show that all clinical and environmental S. maltophilia strains presented comparable distribution of so far identified potential virulence genes, regardless to their virulence potential against amoebae. Aside from that, strain SKK35 was found harboring a putative, strain specific pathogenicity island, encoding two proteins from the RTX (repeats-in-toxin) family. The actual expression of the RTX genes was verified in growth experiments in different culture media containing blood or blood components and in co-cultures with amoeba.
- Bacterial Resistance Control on Mineral Surfaces of Hydroxyapatite and Human Teeth via Surface Charge-Driven Antifouling Coatings. [JOURNAL ARTICLE]
- ACS Appl Mater Interfaces 2014 Feb 18.
This works reports a set of new functionalized polyethyleneimine (PEI) polymers, including a neutral PEGylated polymer PEI-g-PEGMA, a negatively charged polymer PEI-g-SA, and a zwitterionic polymer PEI-g-SBMA, and their use as antibiofouling coating agent for human teeth protection. Polymers were synthesized by Michael addition, XPS analysis revealed that each polymer could be efficiently coated onto hydroxyapatite, ceramic material used as a model tooth. Polymers carrying a negative net charge were more efficiently adsorbed, because of the establishment of electrostatic interactions with calcium ions. Protein adsorption tests revealed that two factors were important in the reduction of protein adsorption. Both the surface charge and the surface ability to bind and entrap water molecules had to be considered. PEI-g-SBMA, which zeta potential in PBS solution was negative, was efficient to inhibit the adsorption of BSA, a negative protein. On the other hand, it also resisted the adsorption of lysozyme, a positive protein, because zwitterionic molecules can easily entrap water and provide a very hydrophilic environment. Streptococcus mutans attachment tests performed unveiled that all modified polymers were efficient to resist this type of bacteria responsible for dental carries. Best results were also obtained with PEI-g-SBMA coating. This polymer was also shown to efficiently resist the adsorption of positively charged bacteria (Stenotrophomonas maltophilia). Tests performed on real human tooth showed that PEI-g-SBMA could inhibit up to 70% of bacteria adhesion, which constitutes a major result considering that surface of teeth is very rough, therefore physically promoting the attachment of proteins and bacteria.
- Laboratory Culture and Maintenance of Stenotrophomonas maltophilia. [Journal Article]
- Curr Protoc Microbiol 2014.:6F.1.1-6.
Stenotrophomonas maltophilia is a ubiquitous soil bacterium that is increasingly recognized as an emerging nosocomial pathogen. This unit includes protocols for the in vitro growth and maintenance of S. maltophilia. Curr. Protoc. Microbiol. 32:6F.1.1-6F.1.6. © 2014 by John Wiley & Sons, Inc.
- The impact of respiratory tract infections on the nutritional state of children with cystic fibrosis. [Journal Article]
- Rev Med Chir Soc Med Nat Iasi 2013 Oct-Dec; 117(4):863-9.
Cystic fibrosis (CF) is a life-shortening, autosomal-recessive disorder characterized by intestinal malabsorption, impaired growth and lung disease. Recurrent pulmonary infections in children with CF are often associated with nutritional deficiencies.To emphasize the effects of recurrent pulmonary infections on nutritional status in children with CF.This retrospective study included 27 patients diagnosed with CF between 1994 and 2011 in the 3rd Pediatric Clinic of the Iasi "Saint Mary" Children's Hospital. The nutritional status was assessed according to ponderal index (PI), body mass index (BMI), Z score for weight and waist. Correlations between the age of onset of symptoms, age at diagnosis, and frequency of infectious episodes, identified bacterial agents and nutritional status were established.Patients aged between 3 months old and 17 years old with an average of 49.48 months +/- 9.83DS; sex ratio was 1.7:1. The patients were diagnosed late, one month to 112 months (average 41.11 months +/- 9.4DS) from the first symptoms until the moment of diagnosis. The clinical forms of CF in the study group were: predominantly respiratory manifestations in 48.14% of cases, and the mixed type, with both respiratory and digestive symptoms, in 18.52% of cases. Delayed weight and/or height gains were identified in 85.19% of cases. The etiologic agents involved in pulmonary infections were Staphylococus aureus (48.14%), Pseudomonas aeruginosa (33.33%), Stenotrophomonas maltophilia (18.51%), Haemophilus influenzae (14.8%), Klebsiella pneumoniae (11.10%), Moraxella catarrhalis (7,40%), Streptococcus pneutmoniae (7.40%), Neisseria sica (7.40%). Pulmonary infections caused by Staphylococus aureus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia were more often associated with nutritional status abnormalities.In small children with CF pulmonary infections due to various causative agents cause a slow rate of growth (both weight and height). Good nutrition and adequate early treatment of pulmonary infections are beneficial for the general state of affected children and are very important in maintaining their health.
- Stent hypersensitivity and infection in sinus cavities. [Journal Article]
- Allergy Rhinol (Providence) 2013; 4(3):e162-5.
Persistent mucosal inflammation, granulation tissue formation, hypersensitivity, and multifactorial infection are newly described complications of retained drug-eluting stents from endoscopic sinus surgery for refractory rhinosinusitis. In an important report published in Allergy and Rhinology, a 45-year-old male patient suffering from recalcitrant chronic rhinosinusitis underwent functional endoscopic sinus surgery and was found, for the first time, to have steroid-eluting catheters that were inadvertently left in the ethmoid and frontal sinuses. The retained catheters had caused persistent mucosal inflammation and formation of granulation tissue denoting hypersensitivity reaction. These consequences had induced perpetuation of symptoms of chronic rhinosinusitis. Meticulous removal of the retained stents with the nitinol wings from inflamed tissues of the frontal, ethmoidal, and sphenoethmoidal recesses in which they were completely imbedded was successfully performed without polypoid regrowth. Cultures of specimens taken from both left and right stents showed heavy growth of Stenotrophomonas maltophilia and moderate growth of Klebsiella oxytoca, coagulase negative Staphylococcus, and beta-hemolytic Streptococcus anginosus. Fungal infection was not detected. The current knowledge and experience regarding stent hypersensitivity and infection in relation with the use of stents in sinus cavities is reviewed.