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Viruses Dec 2023mainly causes respiratory infections that are associated with a high mortality rate among immunocompromised patients. exhibits a high level of antibiotic resistance...
mainly causes respiratory infections that are associated with a high mortality rate among immunocompromised patients. exhibits a high level of antibiotic resistance and can form biofilms, which complicates the treatment of patients infected with this bacterium. Phages combined with antibiotics could be a promising treatment option. Currently, ~60 phages are known, and their effects on biofilm formation and antibiotic sensitivity require further examination. Bacteriophage StM171, which was isolated from hospital wastewater, showed a medium host range, low burst size, and low lytic activity. StM171 has a 44kbp dsDNA genome that encodes 59 open-reading frames. A comparative genomic analysis indicated that StM171, along with the phage Suso (MZ326866) and phage HXX_Dennis (ON711490), are members of a new putative genus. strains that developed resistance to StM171 (bacterial-insensitive mutants) showed a changed sensitivity to antibiotics compared to the originally susceptible strains. Some bacterial-insensitive mutants restored sensitivity to cephalosporin and penicillin-like antibiotics and became resistant to erythromycin. StM171 shows strain- and antibiotic-dependent effects on the biofilm formation of strains.
Topics: Humans; Anti-Bacterial Agents; Bacteriophages; Stenotrophomonas maltophilia; Biofilms
PubMed: 38140696
DOI: 10.3390/v15122455 -
Clinical Infectious Diseases : An... May 2021
Topics: Carbapenems; Gram-Negative Bacterial Infections; Humans; Laboratories; Leukemia, Myeloid, Acute; Microbiota; Stenotrophomonas maltophilia
PubMed: 32544944
DOI: 10.1093/cid/ciaa766 -
Current Microbiology Nov 2023Stenotrophomonas maltophilia is an opportunistic human pathogen associated with nosocomial and community-acquired infections. We have conducted a microbiological and...
Stenotrophomonas maltophilia is an opportunistic human pathogen associated with nosocomial and community-acquired infections. We have conducted a microbiological and genomic surveillance study of broad-spectrum cephalosporin- and carbapenem-resistant Gram-negative bacteria colonizing wild birds inhabiting the Brazilian Amazonia. Strikingly, two S. maltophilia strains (SM79 and SM115) were identified in Plain-throated antwren (Isleria hauxwelli) passerines affected by Amazonian fragmentation and degradation. Noteworthy, SM79 and SM115 strains belonged to new sequence types (STs) ST474 and ST473, respectively, displaying resistance to broad-spectrum β-lactams, aminoglycosides and/or fluoroquinolones. In this regard, resistome analysis confirmed efflux pumps (smeABC, smeDEF, emrAB-tolC and macB), bla and bla, aph(3')-IIc and aac(6')-Iak, and Smqnr resistance genes. Comparative phylogenomic analysis with publicly available S. maltophilia genomes clustered ST473 and ST474 with human strains, whereas the ST474 was also grouped with S. maltophilia strains isolated from water and poultry samples. In summary, we report two novel sequence types of S. maltophilia colonizing wild Amazonian birds. The presence of opportunistic multidrug-resistant pathogens in wild birds, from remotes areas, could represent an ecological problem since these animals could easily promote long-distance dispersal of medically important antimicrobial-resistant bacteria. Therefore, while our results could provide a baseline for future epidemiological genomic studies, considering the limited information regarding S. maltophilia circulating among wild animals, additional studies are necessary to evaluate the clinical impact and degree of pathogenicity of this human opportunistic pathogen in wild birds.
Topics: Humans; Animals; Stenotrophomonas maltophilia; Brazil; Animals, Wild; Microbial Sensitivity Tests; Anti-Bacterial Agents; Gram-Negative Bacterial Infections
PubMed: 38008776
DOI: 10.1007/s00284-023-03532-5 -
Current Microbiology May 2022Stenotrophomonas maltophilia is an environmental bacterium that has gained a lot of attention, as a nosocomial pathogen associated with significant mortality rates....
Stenotrophomonas maltophilia is an environmental bacterium that has gained a lot of attention, as a nosocomial pathogen associated with significant mortality rates. Biofilm formation is considered the corner stone for establishing infections in many bacteria including S. maltophilia. The aim of this study was the genotypic characterization of the different virulence-associated genes and the investigation of the effect of ascorbic acid on S. maltophilia biofilm formation. A total of 20 S. maltophilia isolates from different sources were included in this study. Genes encoding different virulence factors were investigated genotypically. These included stmPr1, stmPr2, smlt3773 locus, smf-1, rpfF, rmlA and spgM. Biofilm formation was investigated phenotypically. The effect of ascorbic acid on biofilm formation was investigated using MIC as well as sub-inhibitory concentrations. Many of the isolates harbored both serine proteases genes stmPr-1 and stmPr-2. Fourteen (70%) of the 20 isolates carried stmPr-1 and 15 (75%) had stmPr-2. Most of the isolates (95%) possessed smlt-3773 locus. Genes linked to biofilm formation such as smf-1, rpfF, rmlA and spgM, were found in (90%), (45%), (85%) and (30%) of the isolates, respectively. Phenotypically, all S. maltophilia isolates (100%) were biofilm producers. Fifteen (75%) were strong biofilm producers and 5 (25%) were moderate biofilm producers. In attempts to seek a non-chemotherapeutic alternative that can hinder biofilm formation without provoking antimicrobial resistance, the results, herein, showed that ascorbic acid inhibits biofilm formation in a dose-dependent manner.
Topics: Ascorbic Acid; Biofilms; Gram-Negative Bacterial Infections; Humans; Stenotrophomonas maltophilia; Virulence
PubMed: 35508743
DOI: 10.1007/s00284-022-02869-7 -
Microbial Drug Resistance (Larchmont,... Dec 2016Stenotrophomonas maltophilia is an emerging nosocomial pathogen responsible for several infections in immunocompromised patients. To characterize the antimicrobial...
Stenotrophomonas maltophilia is an emerging nosocomial pathogen responsible for several infections in immunocompromised patients. To characterize the antimicrobial resistance and virulence potential of this microorganism in a Brazilian hospital, a total of 936 samples were collected from a nosocomial environment and medical devices, and 100 isolates from clinical specimens were obtained in the same hospital. S. maltophilia was found in 3% of the samples collected, especially in bed rails from hospital rooms. The smf-1 gene was detected in 23% and 42% of the clinical and hospital environment isolates, respectively, and almost all (96.8%) isolates that harbored smf-1 were able to form biofilm. All isolates were susceptible to minocycline and chloramphenicol, and the majority of isolates were susceptible to levofloxacin. High resistance to ceftazidime was detected in both groups of isolates. Resistance to trimethoprim-sulfamethoxazole (TMP/SMX) was found in 14.8% of the isolates. All TMP/SMX-resistant isolates presented class 1 integron and sul1 gene, and 47.4% of them also harbored the sul2 gene, which was inserted into a 7.3 kb plasmid. Genetic relatedness among the isolates was evaluated by enterobacterial repetitive intergenic consensus-PCR, and eight genetic patterns were identified. One pattern comprised 54.7% of isolates and was spread among clinical and environmental (furniture and medical devices) sources. The presence of S. maltophilia in the hospital environment indicates that it can act as a reservoir of this microorganism. In addition, hospital isolates resistant to TMP/SMX showed that the genetic determinants were present in mobile elements, which can constitute great concern, as it may indicate a tendency to spread.
Topics: Anti-Bacterial Agents; Bacterial Typing Techniques; Biofilms; Brazil; Ceftazidime; Chloramphenicol; Cross Infection; Drug Resistance, Bacterial; Fomites; Gene Expression Regulation, Bacterial; Genes, Bacterial; Gram-Negative Bacterial Infections; Hospitals; Humans; Integrons; Levofloxacin; Minocycline; Phylogeny; Plasmids; Polymerase Chain Reaction; Stenotrophomonas maltophilia; Trimethoprim, Sulfamethoxazole Drug Combination
PubMed: 27007167
DOI: 10.1089/mdr.2015.0306 -
Microbial Drug Resistance (Larchmont,... Mar 2017Trimethoprim-sulfamethoxazole is the first-line antimicrobial combination for Stenotrophomonas maltophilia infections. However, allergy or intolerance and increasing...
Trimethoprim-sulfamethoxazole is the first-line antimicrobial combination for Stenotrophomonas maltophilia infections. However, allergy or intolerance and increasing resistance limit the use of trimethoprim-sulfamethoxazole. Quinolones can be used as an alternative therapeutic option, but resistance can emerge rapidly during therapy. We analyzed the contribution of SmeABC and SmeDEF efflux pumps to levofloxacin resistance in clinical isolates of S. maltophilia. Nonduplicate clinical isolates of S. maltophilia were collected in 2010 from 11 university hospitals (n = 102). Fifty-five levofloxacin nonsusceptible (minimum inhibitory concentration [MIC] ≥4 μg/ml) and 47 susceptible (MIC ≤2 μg/ml) isolates were tested for efflux pump overexpression. Real-time reverse transcription-PCR was performed for amplification and quantification of smeB, smeC, smeD, and smeF mRNA. To determine which antimicrobials were affected by smeD overexpression, the growth rates of a levofloxacin-susceptible S. maltophilia isolate were compared by measuring absorbance of antimicrobial-supplemented Luria-Bertani broth (LB) cultures with or without triclosan. Significant relationships between sme gene overexpression and resistance were observed for smeD against levofloxacin, smeC and smeF against ceftazidime, and smeC against ticarcillin-clavulanate. The mean MICs of moxifloxacin and tigecycline did not significantly differ for isolates with or without overexpression of smeB, smeC, and smeF, but were significantly higher for isolates with smeD overexpression. The mean MICs of amikacin were significantly higher for smeC or smeF overexpressing isolates. Increased growth of a levofloxacin-susceptible isolate was observed in LB with 1/2 MIC levofloxacin in the presence of triclosan. These data suggest that the expression of smeD plays a role in levofloxacin resistance in S. maltophilia.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Ceftazidime; Drug Resistance, Multiple, Bacterial; Fluoroquinolones; Gram-Negative Bacterial Infections; Humans; Levofloxacin; Membrane Transport Proteins; Microbial Sensitivity Tests; Minocycline; Moxifloxacin; Stenotrophomonas maltophilia; Ticarcillin; Tigecycline; Trimethoprim, Sulfamethoxazole Drug Combination
PubMed: 27294684
DOI: 10.1089/mdr.2015.0228 -
Preparative Biochemistry & Biotechnology 2023This study aimed to determine the ability of bacteria to produce the chitinase enzyme, purify, and characterize the enzyme from the isolate with the best activity, and...
This study aimed to determine the ability of bacteria to produce the chitinase enzyme, purify, and characterize the enzyme from the isolate with the best activity, and determine the use of this purified enzyme as a biocontrol agent. The chitinolytic bacterium was identified as . The chitinase enzyme was purified 1.4 times at a 30% ammonium sulfate concentration with a yield of 40.7%. Following partial purification, the enzyme was purified by ion-exchange chromatography using HiPrep Q XL 16/10 column and HiPrep™ 26/10 desalting column with 25.34% and 18.12% yields, respectively. It was calculated that the purified enzyme had a molecular weight of 52 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The optimum activity of the enzyme was determined at 50 °C and pH 7.0. Enzyme activity was most induced by Fe, while it was most inhibited by Zn at 5 mM concentration. and values of the enzyme for colloidal chitin were calculated as 1.6419 mg/mL and 16.129 U/mg, respectively. The purified chitinase was used as a biocontrol agent against the fungus and potato beetle . The enzyme was shown to be effective in reducing the growth of fungus and causing disruption of the chitin structure of potato beetle.
Topics: Antifungal Agents; Stenotrophomonas maltophilia; Chitinases; Fungi; Chitin; Hydrogen-Ion Concentration; Temperature
PubMed: 36369794
DOI: 10.1080/10826068.2022.2142942 -
Eye & Contact Lens Nov 2018Contact lens cases become contaminated with microbes during use. We wished to compare the adhesion of uncommon bacterial contaminants isolated from lens cases to contact...
PURPOSE
Contact lens cases become contaminated with microbes during use. We wished to compare the adhesion of uncommon bacterial contaminants isolated from lens cases to contact lenses with and without organic soil.
METHODS
Strains of Delftia acidovorans (001), Stenotrophomonas maltophilia (002 and 006), and Achromobacter xylosoxidans (001) isolated from contact lens cases (test strains) and Pseudomonas aeruginosa (Paer1) isolated from eyes at the time of infiltrative response (control strain) were used. Bacteria were grown and resuspended in phosphate-buffered saline (PBS) or 10% organic soil (heat-killed Saccharomyces cerevisiae resuspended in complement inactivated bovine serum). Two silicone hydrogel (senofilcon A and comfilcon A) and one hydrogel lens (etafilcon A) lens materials were used. Bacteria (1.0×10 and 1.0×10 colony-forming units/mL; CFU/mL) adhered to lenses for 24 hr and the numbers of bacteria adherent to each lens type (with and without organic soil) were estimated by culture.
RESULTS
All the four test strains adhered in significantly greater numbers to contact lenses after incubation in inoculum prepared with organic soil compared with PBS-D. acidovorans 001 (0.7 log10 CFU; P<0.05), S. maltophilia 002 (1.7 log10 CFU; P<0.05), S. maltophilia 006 (0.9 log10 CFU; P<0.05), and A. xylosoxidans 001 (0.4 log10 CFU; P<0.05). However, the presence of organic soil did not increase adhesion of P. aeruginosa Paer1 (-0.1 log10 CFU; P>0.05). Achromobacter xylosoxidans 001 (P<0.01), D. acidovorans 001 (P<0.01), and S. maltophilia 002 (P<0.01) significantly differed in their adhesion to the three contact lens materials.
CONCLUSION
Bacteria that are commonly found in contact lens cases adhered to contact lenses in relatively high numbers in the presence of organic soil. This might indicate that a similar phenomenon occurs in the presence of tears. This may facilitate their transfer from the lens to the cornea and the production of corneal infiltrates.
Topics: Achromobacter denitrificans; Bacterial Adhesion; Contact Lenses, Hydrophilic; Delftia acidovorans; Humans; Soil Microbiology; Stenotrophomonas maltophilia
PubMed: 28953600
DOI: 10.1097/ICL.0000000000000425 -
Applied and Environmental Microbiology Jun 2023Stenotrophomonas maltophilia is an environmental bacterium as well as an emerging opportunistic multidrug-resistant pathogen. They use the endogenous diffusible signal...
Stenotrophomonas maltophilia is an environmental bacterium as well as an emerging opportunistic multidrug-resistant pathogen. They use the endogenous diffusible signal factor (DSF) quorum sensing (QS) system to coordinate population behavior and regulate virulence processes but can also respond to exogenous N-acyl-homoserine lactone (AHL) signals produced by neighboring bacteria. The effect of these QS signals on the global gene expression of this species remains, however, unknown. Whole-transcriptome sequencing analyses were performed for exponential cultures of S. maltophilia K279a treated with exogenous DSF or AHLs. Addition of DSF and AHLs signals resulted in changes in expression of at least 2-fold for 28 and 82 genes, respectively. Interestingly, 22 of these genes were found upregulated by both QS signals, 14 of which were shown to also be induced during the stationary phase. Gene functions regulated by all conditions included lipid and amino acid metabolism, stress response and signal transduction, nitrogen and iron metabolism, and adaptation to microoxic conditions. Among the common top upregulated QS core genes, a putative TetR-like regulator (locus tag SMLT2053) was selected for functional characterization. This regulator controls its own β-oxidation operon (-), and it is found to sense long-chain fatty acids (FAs), including the QS signal DSF. Gene knockout experiments reveal that operon - is involved in biofilm formation. Overall, our findings provide clues on the effect that QS signals have in S. maltophilia QS-related phenotypes and the transition from the exponential to the stationary phase and bacterial fitness under high-density growth. The quorum sensing system in Stenotrophomonas maltophilia, in addition to coordinating the bacterial population, controls virulence-associated phenotypes, such as biofilm formation, motility, protease production, and antibiotic resistance mechanisms. Biofilm formation is frequently associated with the persistence and chronic nature of nosocomial infections. In addition, biofilms exhibit high resistance to antibiotics, making treatment of these infections extremely difficult. The importance of studying the metabolic and regulatory systems controlled by quorum sensing autoinducers will make it possible to discover new targets to control pathogenicity mechanisms in S. maltophilia.
Topics: Quorum Sensing; Stenotrophomonas maltophilia; Biofilms; Virulence; Acyl-Butyrolactones; Fatty Acids
PubMed: 37272812
DOI: 10.1128/aem.00635-23 -
Microbiology Spectrum Aug 2022Seven drug-resistant strains of Stenotrophomonas maltophilia were isolated from patients at two university hospitals in Nepal. S. maltophilia JUNP497 was found to encode...
Stenotrophomonas maltophilia from Nepal Producing Two Novel Antibiotic Inactivating Enzymes, a Class A β-Lactamase KBL-1 and an Aminoglycoside 6'--Acetyltransferase AAC(6')-Iap.
Seven drug-resistant strains of Stenotrophomonas maltophilia were isolated from patients at two university hospitals in Nepal. S. maltophilia JUNP497 was found to encode a novel class A β-lactamase, KBL-1 (Kathmandu β-lactamase), consisting of 286 amino acids with 52.98% identity to PSV-1. Escherichia coli transformants expressing were less susceptible to penicillins. The recombinant KBL-1 protein efficiently hydrolyzed penicillins. The genomic environment surrounding was a unique structure, with the upstream region derived from strains in China and the downstream region from strains in India. S. maltophilia JUNP350 was found to encode a novel 6'-N-aminoglycoside acetyltransferase, AAC(6')-Iap, consisting of 155 amino acids with 85.0% identity to AAC(6')-Iz. E. coli transformants expressing were less susceptible to arbekacin, amikacin, dibekacin, isepamicin, neomycin, netilmicin, sisomicin and tobramycin. The recombinant AAC(6')-Iap protein acetylated all aminoglycosides tested, except for apramycin and paromomycin. The genomic environment surrounding was 90.99% identical to that of S. maltophilia JV3 obtained from a rhizosphere in Brazil. Phylogenetic analysis based on whole genome sequences showed that most S. maltophilia isolates in Nepal were similar to those isolates in European countries, including Germany and Spain. The emergence of drug-resistant S. maltophilia has become a serious problem in medical settings worldwide. The present study demonstrated that drug-resistant S. maltophilia strains in Nepal harbored novel genes encoding a class A β-lactamase, KBL-1, or a 6'-N-aminoglycoside acetyltransferase, AAC(6')-Iap. Genetic backgrounds of most S. maltophilia strains in Nepal were similar to those in European countries. Surveillance of drug-resistant S. maltophilia in medical settings in Nepal is necessary.
Topics: Acetyltransferases; Amino Acids; Anti-Bacterial Agents; Escherichia coli; Humans; Microbial Sensitivity Tests; Nepal; Penicillins; Phylogeny; Stenotrophomonas maltophilia; beta-Lactamases
PubMed: 35862995
DOI: 10.1128/spectrum.01143-22