Antimicrobial susceptibility of hospital acquired Stenotrophomonas maltophilia isolate biofilms

Abstract Aims We sought to characterize the antibiotic susceptibility of strains of Stenotrophomonas maltophilia isolated from clinical samples, and the role of Stenotrophomonas maltophilia biofilm in antibiotic resistance. Methods Fifty-one clinical Stenotrophomonas maltophilia isolates were obtained from patients with nosocomial infection in the surgical wards and ICUs of six general hospitals in Tianjin, China. In vitro models of Stenotrophomonas maltophilia biofilms were established and confirmed by scanning electron microscopy and fluorescence microscopy with silver staining. The minimal inhibitory concentrations and biofilm inhibitory concentrations of commonly used antibiotics were determined. Results 47 of 51 strains were resistant to three or more antibiotics. 42 of 51 strains formed Stenotrophomonas maltophilia biofilms in vitro. Stenotrophomonas maltophilia biofilm formation greatly reduced sensitivity to most tested antibiotics, but not to levofloxacin. However, in the presence of erythromycin scanning electron microscopy revealed that levofloxacin inhibited Stenotrophomonas maltophilia biofilm formation. Factorial ANOVA revealed that erythromycin enhanced susceptibility to levofloxacin, cefoperazone/sulbactam, and piperacillin (p < 0.05), and an ΔE model revealed that levofloxacin and erythromycin acted synergistically in biofilms, suggesting specific use of combined macrolide therapy may represent an effective treatment for Stenotrophomonas maltophilia infection. Conclusions Antibiotics could act synergistically to combat the protection conferred to clinical isolates of Stenotrophomonas maltophilia by biofilms. Macrolide antibiotics may be effective where used in combination.

Analysis of the diagnosis and treatment of desmoplastic small round cell tumor / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the clinical diagnostic features and treatment of desmoplastic small round cell tumor (DSRCT), and to improve the understanding and management of this tumor.</p><p><b>METHODS</b>The clinicopathological data of nine patients treated in our hospital from October 2004 to June 2014 were retrospectively analyzed and a review of the literature was made. The clinical manifestations, pathological characteristics, diagnosis and differential diagnosis, treatment and prognosis of this tumor were summarized and analyzed.</p><p><b>RESULTS</b>Nine patients with DSRCT, 5 males and 4 females, with an average age of 21 years (range 8-56 years) were included in this study. Ultrasound examination revealed irregular low-density mass shadow in the abdominal cavity. CT examination found that 6 cases had abdominal and retroperitoneal multiple solid tumor nodules, uneven density, and visible low density fluid area. Postoperative pathological examination revealed that the tumor cells were small, mostly elliptic, gathered to form clear structure of nests with clear irregular boundaries. The central portion of large tumor nests often showed necrosis. Scattered fibroblasts and large amount of hyalinization of collagen fibers were seen in the interstitial tissue around the nests. Six patients received laparotomy surgery, however, all failed to resect the tumor completely. Three patients received postoperative chemotherapy, i. e. two cases had carboplatin and paclitaxel chemotherapy, and one case of chemotherapy regimen not specified. Two patients had radiation and chemotherapy (no concrete plan was available). Another case was lost to follow-up. Two of the three patients without surgery received chemotherapy with CAP (cyclophosphamide+adriamycin+carboplatin) and total rectal lesions, pelvic and inguinal lymph nodes, ilium metastases radiation therapy. Another one patient received EP regimen (DDP+VP16) which was then changed into a TP chemotherapy alone. Eight of the nine cases died shortly after surgery, and only one patient treated with chemotherapy alone was still alive after 11 months of follow-up.</p><p><b>CONCLUSIONS</b>Desmoplastic small round cell tumor is a very rare, special type of soft tissue tumor, with very poor prognosis. This tumor may be preliminarily diagnosed according to the imaging characteristics and detection of tumor markers, however, final diagnosis is made by pathology. Surgery is the priority of treatment, combined with complementary radiation and chemotherapy.</p>