Advances in genomics of multi-drug resistant Stenotrophomonas / 生物工程学报

Stenotrophomonas species are non-fermentative Gram-negative bacteria that are widely distributed in environment and are highly resistant to numerous antibiotics. Thus, Stenotrophomonas serves as a reservoir of genes encoding antimicrobial resistance (AMR). The detection rate of Stenotrophomonas is rapidly increasing alongside their strengthening intrinsic ability to tolerate a variety of clinical antibiotics. This review illustrated the current genomics advances of antibiotic resistant Stenotrophomonas, highlighting the importance of precise identification and sequence editing. In addition, AMR diversity and transferability have been assessed by the developed bioinformatics tools. However, the working models of AMR in Stenotrophomonas are cryptic and urgently required to be determined. Comparative genomics is envisioned to facilitate the prevention and control of AMR, as well as to gain insights into bacterial adaptability and drug development.

The microbiome of the lung and its extracellular vesicles in nonsmokers, healthy smokers and COPD patients

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease, and bacterial infection plays a role in its pathogenesis. Bacteria secrete nanometer-sized extracellular vesicles (EVs), which may induce more immune dysfunction and inflammation than the bacteria themselves. We hypothesized that the microbiome of lung EVs might have distinct characteristics depending on the presence of COPD and smoking status. We analyzed and compared the microbiomes of 13 nonsmokers with normal spirometry, 13 smokers with normal spirometry (healthy smokers) and 13 patients with COPD by using 16S ribosomal RNA gene sequencing of surgical lung tissue and lung EVs. Subjects were matched for age and sex in all groups and for smoking levels in the COPD and healthy smoker groups. Each group included 12 men and 1 woman with the same mean age of 65.5 years. In all groups, EVs consistently showed more operational taxonomic units (OTUs) than lung tissue. In the healthy smoker and COPD groups, EVs had a higher Shannon index and a lower Simpson index than lung tissue and this trend was more prominent in the COPD group. Principal component analysis (PCA) showed clusters based on sample type rather than participants' clinical characteristics. Stenotrophomonas, Propionibacterium and Alicyclobacillus were the most commonly found genera. Firmicutes were highly present in the EVs of the COPD group compared with other samples or groups. Our analysis of the lung microbiome revealed that the bacterial communities present in the EVs and in the COPD group possessed distinct characteristics with differences in the OTUs, diversity indexes and PCA clustering.

Endophthalmitis Caused by Stenotrophomonas maltophilia after Cataract Surgery: Clinical Features, Antibiotic Sensitivities, and Outcomes

PURPOSE: To describe the clinical manifestations, treatment results, and antibiotic susceptibility in 6 cases of Stenotrophomonas maltophilia endophthalmitis. METHODS: We retrospectively reviewed 6 eyes of 6 patients who were diagnosed with Stenotrophomonas maltophilia endophthalmitis. Specifically, we considered each patient's age, sex, past history, visual acuity, hypopyon, treatment, and prognosis. RESULTS: For our study, we considered patients treated during the period of January 2008 to December 2015. Stenotrophomonas maltophilia (6 eyes) was the second most common gram-negative bacteria cause of total bacterial endophthalmitis while Pseudomonas aeruginosa (14 eyes) was the most common gram-negative bacteria cause during the same period. Visual disturbance was the dominant symptom being found in all 6 patients. Other symptoms include ocular pain and hypopyon. The initial visual acuity was light perception (1 patient), hand motion (3 patients), finger count (1 patient), and 0.02 (1 patient). Excluding the 1 patient with light perception, the mean initial visual acuity was logMAR 1.72 (Snellen equivalent; 20/1,049). Overall, 5 patients underwent vitrectomy and intravitreal antibiotics injection, while, the remaining other patient was treated with intravitreal antibiotics injection, followed by vitrectomy. All 6 patients showed sensitivity to Ceftazidime and Levofloxacin and 2 patients showed sensitivity to Trimethoprim/Sulfamethoxazole. CONCLUSIONS: Stenotrophomonas maltophilia endophthalmitis was the second most common gram negative organism to cause endophthalmitis after cataract surgery. All 6 of the tested isolates were found to be sensitive to ceftazidime and levofloxacin. Urgent treatment outcomes were similar to previous reports.

Efflux Pump Inhibitor Carbonyl Cyanide-m-chlorophenylhydrazone (CCCP) Enhances Bacteriostatic Activity of Trimethoprim-sulfamethoxazole Against Clinical Stenotrophomonas maltophilia Isolates from Korea

Although trimethoprim-sulfamethoxazole (TMP-SXT) is considered the first-line therapy for Stenotrophomonas maltophilia infections, there is debate on the use of the bacteriostatic drug in serious infections, and recently, there has been an increasing occurrence of acquired resistance to TMP-SXT. In the present study, the effect of efflux pump inhibitors on the susceptibility of TMP-SXT and other antibiotics were investigated in S. maltophilia complex. The sul and/or dfrA genes were identified in only up to 27.8% of all 36 TMP-SXT-resistant S. maltophilia complex isolates. Thus, TMP-SXT resistance in S. maltophilia was not explained completely by the presence of sul and dfrA genes. Carbonyl cyanide-m-chlorophenylhydrazone (CCCP) decreased the minimum inhibitory concentration (MIC) of TMP-SXT by eight to 128 folds in all 14 isolates. In contrast, 2,4-dinitrophenol (DNP), phenyl-arginine-β-naphthylamide (PAβN), and reserpine did not reduce the MIC of TMP-SXT. In addition to TMP-SXT, slight decrease in MICs was observed for tigecycline and piperacillin/tazobactam by CCCP (by two folds) in one isolate. Although efflux pump may play a role in TMP-SXT resistance in S. maltophilia, inhibition of the efflux pump could be done by active proton pore.

Computed Tomography Findings of Community-Acquired Stenotrophomonas Maltophilia Pneumonia in an Immunocompetent Patient: A Case Report

Stenotrophomonas maltophilia (S. maltophilia) is a rare, but globally emerging gram-negative multiple-drug-resistant organism usually found in a nosocomial setting in immunocompromised patients. To our best knowledge, computed tomography (CT) features of community-acquired S. maltophilia pneumonia have not been previously reported in an immunocompetent patient. Herein, we presented the CT findings of a previous healthy 56-year-old male with S. maltophilia pneumonia.

Current Situation of Antimicrobial Resistance and Genetic Differences in Stenotrophomonas maltophilia Complex Isolates by Multilocus Variable Number of Tandem Repeat Analysis / 감염과화학요법

BACKGROUND: Stenotrophomonas maltophilia is one of several opportunistic pathogens of growing significance. Several studies on the molecular epidemiology of S. maltophilia have shown clinical isolates to be genetically diverse. MATERIALS AND METHODS: A total of 121 clinical isolates tentatively identified as S. malophilia from seven tertiary-care hospitals in Korea from 2007 to 2011 were included. Species and groups were identified using partial gyrB gene sequences and antimicrobial susceptibility testing was performed using a broth microdilution method. Multi locus variable number of tandem repeat analysis (MLVA) surveys are used for subtyping. RESULTS: Based on partial gyrB gene sequences, 118 isolates were identified as belonging to the S. maltophilia complex. For all S. maltophilia isolates, the resistance rates to trimethoprime-sulfamethoxazole (TMP/SMX) and levofloxacin were the highest (both, 30.5%). Resistance rate to ceftazidime was 28.0%. 11.0% and 11.9% of 118 S. maltophilia isolates displayed resistance to piperacillin/tazobactam and tigecycline, respectively. Clade 1 and Clade 2 were definitely distinguished from the data of MLVA with amplification of loci. All 118 isolates were classified into several clusters as its identification. CONCLUSION: 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.

Stenotrophomonas maltophilia and Ventilator-Associated Pneumonia in Critically Ill Pediatric Patients: a Retrospective Analysis at a Single Center

PURPOSE: Ventilator-associated pneumonia (VAP) is a serious threat in critically ill pediatric patients. Data regarding Stenotrophomonas maltophilia VAP in pediatric population is limited. We evaluated the clinical data of S. maltophilia associated VAP in critically ill pediatric patients. METHODS: A retrospective chart review was performed in pediatric patients 18 years old or younger who developed S. maltophilia associated VAP at Samsung Medical Center, Seoul Korea from January 2008 to December 2012. RESULTS: A total of 31 patients were identified S. maltophilia associated VAP. Median age was 8 months (range, 0.5 month to 16.6 years) and 13 patients were male (40.6%). Underlying illnesses were cardiologic diseases (n=11, 34.4%), hematologic oncologic malignancies (n=7, 25%), neurologic diseases (n=4, 12.5%), pulmonary diseases (n=3, 9.4%), and others (n=4, 12.5%). The median duration of ventilator use before S. maltophilia VAP diagnosis was 14 days (range, 4-256 days). Overall mortality at 30 days was 12.5% (4/32). CONCLUSIONS: S. maltophilia should be also considered as a possible pathogen for VAP in critically ill pediatric patients. Empiric antibiotic choice should include agents that are active against S. maltophilia in patients who are deteriorating on broad spectrum beta-lactam antimicrobial agents.

Effects of different osmolarities on bacterial biofilm formation

Biofilm formation depends on several factors. The influence of different osmolarities on bacterial biofilm formation was studied. Two strains (Enterobacter sp. and Stenotrophomonas sp.) exhibited the most remarkable alterations. Biofilm formation is an important trait and its use has been associated to the protection of organisms against environmental stresses.

Empirical Treatment of Highly Suspected Nontuberculous Mycobacteria Infections Following Aesthetic Procedures

BACKGROUND: Infection caused by nontuberculous mycobacteria (NTM) has been increasing. Awareness of this infection is crucial yet problematic. Delayed management may lead to destructive results. We empirically treated a series of patients with clinical suspicion of NTM infection prior to the identification of the pathogen. METHODS: A total of 12 patients who developed surgical site infections between January 2011 and February 2014 were reviewed. Patients with a skin and subcutaneous infection resistant to standard management over two weeks, and previous history of aesthetic procedures within three months were regarded as highly suspected of having an NTM infection. A variety of diagnostic modalities were examined simultaneously, along with starting empirical treatment including a combination of clarithromycin and moxifloxacin, and surgical debridement. RESULTS: All wounds healed completely within 4 weeks. The mean follow-up duration was 7.2 months, and none of the patients developed relapse. Specific NTM pathogens were identified in six patients. Eight patients showed caseating granuloma implying an NTM infection. One patient showed an uncommon Stenotrophomonas infection, which was successfully treated. Three patients had no evidence of a pathogen despite repeated microbial tests. Complications such as scarring, pigmentation, and disfigurement were common in all the patients. CONCLUSIONS: NTM should be considered in the differential diagnosis of an unusual skin and soft-tissue infection. We propose an empirical regimen of clarithromycin and moxifloxacin as an efficient treatment option for an NTM infection.

Identification of bacterial strain ge15 and its controlling effect on ginseng diseases / 中国中药杂志

Based on previous results of 16S rDNA sequence homologuous and results of physic-biochemical indexes and morphological characteristics in the present work, bacterial strain ge15 isolated from roots of ginseng plants was identified as Stenotrophomonas rhizophila. Confronting incubation results showed that, strain ge15 inhibited the growth of Alternaria panax, Phytophthora cactorum, and Cylindrocapon destructans significantly, and the width of inhibition zone was 13.3, 24.0, 12.0 mm, respectively. Further results showed that the emergence rate and seedling survive rate of ge15 treatment was significantly higher than those of the control, and which was similar to pesticide carbendazol treatment. The ge15 strain has good application potential in ginseng diseases control without contamination.

Characteristic of bacterial flora from the uterus in HanWoo cattle / 대한수의학회지

Uterine sterilization is important for improving fertility in cattle. This study compared bacterial flora in the uterus between healthy and repeat breeder cows (RBCs). The uterine flushing of six heifers, 13 healthy HanWoo cows and eight RBCs (HanWoo) were sampled, and 15 frozen semen samples were selected. Overall, 35 bacteria were identified from in HanWoo uterine flushing and semen. The bacterial genera identified from HanWoo uterine flushing were Alloiococcus, Bacillus, Enterobacter, Enterococcus, Erysipelothrix, Gardnerella, Granulicatella, Kocuria, Pantoea, Pasteurella, Rothia, Serratia, Sphingomonas, Staphylococcus, Stenotrophomonas and Streptococcus. The bacterial genera identified from HanWoo semen were Bacillus, Escherichia, Kocuria, Oligella, Pseudomonas, Serratia, Sphingomonas, Staphylococcus, Stenotrophomonas and Streptococcus. The prevalence and presence of the identified bacteria between healthy cows and RBCs differed significantly. Further studies are needed to determine the role of these bacteria in the uterus of HanWoo cattle with reproductive disorder.

A Case of Continuous Ambulatory Peritonitis Dialysis Peritonitis Due to Stenotrophomonas maltophilia Using Antibiotic Combination / 영남의대학술지

Continuous ambulatory peritoneal dialysis (CAPD) peritonitis is a major complication of peritoneal dialysis (PD) and leads to the discontinuation of PD. Despite its limited pathogenicity, CAPD peritonitis caused by Stenotrophomonas maltophilia (S. maltophilia), an important nosocomial pathogen that is present in nature and is usually associated with plastic indwelling devices. Infection of S. maltophilia is associated with a poor prognosis, including inability to maintain the CAPD catheter, because of its resistance to multiple antibiotics. We report a case of CAPD peritonitis due to S. maltophilia that was treated successfully using oral Trimethoprim-sulfame-thoxazole and intraperitoneal Ticarcillin/clavulanate without removing the dialysis catheter.

Hydrocarbon degrading microflora in a tropical fuel-contaminated aquifer: assessing the feasibility of PAH bioremediation

An aquifer located within a petroleum processing plant in Moin, Costa Rica, suffers hydrocarbon pollution. This study aimed to determine the ability of indigenous microorganisms from this site to degrade polycyclic aromatic hydrocarbons [PAHs] to evaluate the feasibility of an eventual bioremediation process. Aerobic conditions were found in the aquifer, while microbial analyses of the groundwater indicated the presence of important hydrocarbon-degrading populations. Sixteen PAH-degrading strains were isolated with the ability to grow on naphthalene [5 strains], phenanthrene [3], fluorene [6] and pyrene [2]. Most of the identified isolates belonged to the genus Pseudomonas, although, Comamonas, Sphingomonas Stenotrophomonas and Delftia were also found. A mixture of selected strains was evaluated by its performance of PAH degradation in soil-slurry systems, where efficiency of removal was naphthalene > fluorene > phenanthrene > pyrene. This study is an initial approach to evaluate the feasibility of applying a bioremediation process in the contaminated site

Two Different Cases of Stenotrophomonas Maltophilia Endophthalmitis after Cataract Surgery

PURPOSE: To report 2 different cases of postoperative endophthalmitis caused by Stenotrophomonas maltophilia after cataract surgery. CASE SUMMARY: A 73-year-old male with diabetes mellitus developed severe pain in the right eye 2 weeks after cataract surgery. The patient was hospitalized with a diagnosis of infectious endophthalmitis, and vitrectomy was performed. Cultures of aqueous humor and vitreous aspirate revealed S. maltophilia. On day 30 after vitrectomy, his visual acuity had improved to 20/20 and there were no recurrences. A 61-year-old female with no significant past medical history was referred for uveitis or delayed onset endophthalmitis 30 days after cataract surgery. An anterior chamber tapping and cultures were performed. S. maltophilia and Aspergillus fumigatus were isolated. The patient received antibiotics and antifungal agents and her visual acuity improved to 20/25. CONCLUSIONS: S. maltophilia has been considered a life-threatening systemic opportunistic infection; however, the organism has recently been reported as an exogenous pathogen of endophthalmitis following cataract surgery. Herein, 2 different cases of S. maltophilia endophthalmitis after cataract surgery are presented and compared with previous case reports.

An MLSA-based online scheme for the rapid identification of Stenotrophomonas isolates

An online scheme to assign Stenotrophomonas isolates to genomic groups was developed using the multilocus sequence analysis (MLSA), which is based on the DNA sequencing of selected fragments of the housekeeping genes ATP synthase alpha subunit (atpA), the recombination repair protein (recA), the RNA polymerase alpha subunit (rpoA) and the excision repair beta subunit (uvrB). This MLSA-based scheme was validated using eight of the 10 Stenotrophomonas species that have been previously described. The environmental and nosocomial Stenotrophomonas strains were characterised using MLSA, 16S rRNA sequencing and DNA-DNA hybridisation (DDH) analyses. Strains of the same species were found to have greater than 95 percent concatenated sequence similarity and specific strains formed cohesive readily recognisable phylogenetic groups. Therefore, MLSA appeared to be an effective alternative methodology to amplified fragment length polymorphism fingerprint and DDH techniques. Strains of Stenotrophomonas can be readily assigned through the open database resource that was developed in the current study (www.steno.lncc.br/).

Succession and growth strategy of a spring microbial community from kezhou sinter in China

The succession and growth strategy of a spring microbial community under earthquake action were investigated. The majority of pre-earthquake isolates belonged to the Gammaproteobacteria, including two numerically dominant Stenotrophomonas sp. RB25 and Acinetobacter sp. RB11 (r-strategists). The predominant post-earthquake isolates were Alphaproteobacteria, with Rhizobium sp. RA42 (K-strategists) being dominant among these organisms.

Isolation and molecular characterization of some copper biosorped strains

TThe biosorption of copper [II] from aqueous solution using different bacterial strains was studied. Copper-biosorbing bacteria were isolated from tannery effluent collected from Borg Al-Arab, Alexandria, Egypt. These isolates displayed different degrees of copper biosorption under aerobic conditions. Based on 16S rDNA gene sequence analysis, three of them [S2, S5 and S7] were identified as Chryseobacterium sp., Enterobacter sp. and Stenotrophomonas sp., respectively. Initial copper [II] ion concentrations from 25-250 mg/L at constant temperature 30°C were studied. The residual copper [II] concentration and its toxicity effect in solution were determined using atomic absorption spectrophotometer and bioluminescent bioreporter. The bioluminescence inhibition of strain [S5] reached to 91.4% as compared with the strain [S7] reached to 83.3% at 225 mg/L of copper ion where the maximum biosorption efficiency for S5 and S7 were 71% and 70.1% correspondingly using atomic absorption. The biolumi-nescent bioreporter was proved to be fast and accurate technique for measurement the toxicity effect of residual copper [II] in solution

A Case of Metastatic Cellulitis Caused by Stenotrophomonas maltophilia / 대한피부과학회지

Stenotrophomonas maltophiliais a nonfermentative Gram-negative bacillus, and this is an emerging pathogen for nosocomial infection. It is commonly associated with pneumonia and catheter-related bacteremia, and especially in immunocompromised patients. Cutaneous infection with Stenotrophomonas maltophilia is uncommon, yet it may cause therapeutic problems because of its intrinsic resistance to common antibiotics and the immunodeficiency of the affected host. Herein, we report on a case of metastatic cellulitis secondary to Stenotrophomonas maltophilia bacteremia, and this developed in an immunocompromised patient. He was successfully treated with intravenous trimethoprim-sulfamethoxazole.

A case of soft tissue infection by Stenotrophomonas maltophilia manifesting as subcutaneous nodules in a patient with leukemia / 대한내과학회지

Stenotrophomonas maltophilia is a ubiquitous, Gram-negative organism. It is an emerging causative pathogen for severe hospital- acquired infections, particularly in debilitated or immunocompromised patients because of its resistance to various antibiotics. Soft tissue infection caused by S. maltophilia, however, is uncommon. A patient with leukemia was referred for the evaluation of subcutaneous nodules that developed after chemotherapy. With the pathological finding of neutrophilic panniculitis, S. maltophilia was confirmed in a bacteriological study of the biopsied tissue. The nodules regressed spontaneously with recovery from the neutropenia. We report a case of S. maltophilia infection that manifested as soft tissue nodules, which resolved spontaneously in a patient with leukemia.

Ecthyma Gangrenosum: A Rare Cutaneous Manifestation Caused by Stenotrophomonas maltophilia in a Leukemic Patient

Ecthyma gangrenosum (EG) is a well-recognized cutaneous infection that most commonly affects immunocompromised patients. It typically occurs on the extremities, or in gluteal and perineal regions. Although Pseudomonas aeruginosa is the most well-known pathogen causing EG, other organisms have been reported to cause EG. Herein we report a rare case of ecthyma gangrenosum presenting as aggressive necrotic skin lesions in perioral and infraorbital areas in a 47-year-old patient with acute myelocytic leukemia after allogeneic bone marrow transplantation. It was caused by Stenotrophomonas maltophilia, which is an aerobic, gram-negative pathogen that has been associated only rarely with cutaneous disease. Blood culture and tissue culture were positive for S. maltophilia. Histological examination revealed numerous tiny bacilli in the dermis and perivascular area. Early recognition of skin lesions caused by S. maltophilia is important to decrease associated mortality in immunosuppressed patients.