The Diagnostic Value of Procalcitonin Versus Other Biomarkers in Prediction of Bloodstream Infection.

BACKGROUND: We compared the diagnostic utility of procalcitonin (PCT), C-reactive protein (CRP), and hematological markers, including white blood cell count (WBC), neutrophils (NEU), percentage of neutrophils (NEU%), lymphocytes (LYM), neutrophil-lymphocyte count ratio (NLCR), and platelet count (PLT) for predicting bloodstream infection (BSI), which was confirmed by blood culture (BC). METHODS: A retrospective analysis was conducted for 1807 inpatients. The level of PCT, CRP, blood cells, and blood culture results were compared between the positive blood culture group and negative blood culture group; each indicator was analyzed in the performance of bacterial BSI diagnosis by drawing ROC curves. RESULTS: Blood cultures were positive in 230 patients; hence, the prevalence of bacteremia was 12.7%. There were significant differences in the median value for each marker between positive group BCs and negative group BCs (p < 0.05). The areas under the receiver operating characteristic curves (ROC-AUCs) of PCT, CRP, WBC, NEU, NUE%, LYM, NLCR, and PLT for discriminating positive BCs from negative BCs were 0.811, 0.654, 0.612, 0.634, 0.684, 0.595, 0.682, and 0.633 respectively. PCT concentrations of gram-negative (14.94 ng/mL, IQR 2.93  48.76) were significantly higher than gram-positive (4.74 ng/mL, IQR 1.22  17.5) and fungal (1.47 ng/mL, IQR 0.66  35.34). CONCLUSIONS: PCT proved to be the most reliable predictor of BSI, second were NEU% and NLCR. A higher PCT level was found in patients with a gram-negative BSI compared to gram-positive BSI and fungal BSI.

Novel perfusion-decellularized method to prepare decellularized ureters for ureteral tissue-engineered repair.

As the endoscopic technique is widely used in the diagnosis and treatment of diseases, the incidence of ureteral injuries increases annually. The classical surgical therapies are not always satisfactory. With the constant development of the tissue engineering technology in the field of urinary reconstruction, the ureteral reconstruction has become possible technology. In this study, a novel perfusion-decellularized protocol, which combined a perfusion system with the commonly used physical and chemical methods, was used to prepare the decellularized ureters for ureteral reconstruction and the urinary tract-derived cells (UDCs) were seeded on the surface of the perfusion-decellularized ureters (PDUs) in order to observe the cells survival, adhesion, proliferation and distribution. The data of H&E staining, DAPI staining, and the agarose gel electrophoresis demonstrated that the cellular components of PDUs were removed, and the decellularized time was shorter than previous study. In addition, compared with the native ureters, the DNA content of the PDUs was significantly decreased just two percent residue (P<0.05). Scanning electron microscopy, collagen and glycosaminoglycan content assay showed that the three-dimensional (3D) ultrastructure and the compositions of the extracellular matrix (ECM) of PDUs were well preserved. When the UDCs were seeded onto the PDUs, the UDCs formed multilayer structure on the surface of the PDUs, infiltrated into the deep layer of the decellularized ureters and then formed laminated structure. In conclusion, the decellularized ureters prepared by the novel perfusion-decellularized method may be the potential surrogate for ureteral tissue-engineered repair.

Overexpression of MexAB-OprM efflux pump in carbapenem-resistant Pseudomonas aeruginosa.

Efflux pump systems are one of the most important mechanisms conferring multidrug resistance in Pseudomonas aeruginosa. MexAB-OprM efflux pump is one of the largest multi-drug resistant efflux pumps with high-level expression, which is controlled by regulatory genes mexR, nalC, and nalD. This study investigated the role of efflux pump MexAB-OprM in 75 strains of carbapenem-resistant P. aeruginosa and evaluated the influence of point mutation of the regulatory genes. The minimum inhibitory concentrations of imipenem and meropenem, with or without MC207110, an efflux pump inhibitor, were determined by agar dilution method to select the positive strains for an overexpressed active efflux pump. Carba NP test and EDTA-disk synergy test were used for the detection of carbapenemase and metallo-ß-lactamases, respectively. The gene mexA, responsible for the fusion protein structure, and the reference gene rpoD of the MexAB-OprM pump were amplified by real-time PCR. The quantity of relative mRNA expression was determined simultaneously. By PCR method, the efflux regulatory genes mexR, nalC, and nalD and outer membrane protein OprD2 were amplified for the strains showing overexpression of MexAB-OprM and subsequently analyzed by BLAST. Among the 75 P. aeruginosa strains, the prevalence of efflux pump-positive phenotype was 17.3 % (13/75). Carba NP test and EDTA-disk synergy test were all negative in the 13 strains. PCR assay results showed that ten strains overexpressed the MexAB-OprM efflux pump and were all positive for the regulatory genes mexR, nalC, and nalD. Sequence analysis indicated that of the ten isolates, nine had a mutation (Gly â†’ Glu) at 71st amino acid position in NalC, and eight also had a mutation (Ser â†’ Arg) at 209th position in NalC. Only one strain had a mutation (Thr â†’ Ile) at the 158th amino acid position in NalD, whereas eight isolates had mutations in MexR. In conclusion, overexpression of efflux pump MexAB-OprM plays an important role in carbapenem-resistant P. aeruginosa. The mutations of regulatory genes may be a main factor contributing to overexpression of MexAB-OprM.

[A perfusion system for preparing canine ureteral acellular matrix].

OBJECTIVE: To explore the feasibility of preparing ureteral acellular matrix (UAM) using perfusion systems. METHODS: Using the luminal structure of the ureter, the UAM was prepared by perfusing canine ureter with SDS, TritonX-100, or both. The residual nuclei in the UAM were evaluated using HE staining, DAPI staining, DNA quantification, and agarose gel electrophoresis. The three-dimensional ultrastructure and the bioactive components were evaluated by Masson's trichrome staining, Alcian Blue staining, collagen quantification, GAG quantification, scanning electron microscopy (SEM), and toxicity detection. RESULTS: HE staining and DAPI staining showed the absence of obvious nuclear materials in the combined group, which was further confirmed by DNA quantification and agarose gel electrophoresis. Masson's trichrome staining, Alcian Blue staining, collagen quantification and GAG quantification all verified that the ultrastructure and the bioactive components were well preserved in the combined group. SEM showed a large amount of porous structure on the surface of the UAM prepared by combined perfusion, and toxicity assay confirmed that the prepared UAM was nontoxic. CONCLUSION: Perfusion of canine ureter with SDS and TritonX-100 is feasible to prepare UAM for ureteral reconstruction.

Study of clinical practical model of urinary system injury.

BACKGROUND: In order to improve the clinical treatment level of urinary system injury, it is necessary to build up an animal model of urinary system wound, which is not only analogous to real clinical practice, but also simple and practical. METHODS: We have developed the third generation of firearm fragment wound generator based on the first and the second producer. The best explosive charge of the blank cartridge was selected by gradient powder loading experiments. The firearm fragment injuries were made to the bulbous urethra of 10 New Zealand male rabbits. One week preoperatively and 2, 4 and 8 weeks postoperatively, all the animals underwent urethroscopy and urethrography. At 2, 4 and 8 weeks postoperatively, two animals were randomly selected and killed, and the urethra was cut off for pathological examination. RESULTS: The shooting distance of the third generation of firearm fragment wound generator is 2 cm. The best explosive charge of the blank cartridge is 1 g of nitrocotton. All rabbits survived the procedures and stayed alive until they were killed. Injuries were limited to bulbous urethra and distal urethra. Round damaged areas, 1-1.5 cm in length, on the ventral wall were observed. Ureteroscopy results showed that canal diameter gradually shrank by over 50% in 9 rabbits. The rate of success was 90%. Urethrography result noted that a 1-1.3 cm stricture was formed at the bulbous urethra. Histology results of injured stricture urethra showed that fibrous connective tissue hyperplasia and hyaline degeneration caused further stricture in the canal. CONCLUSIONS: The third generation of firearm fragment wound generator imitates the bullet firing process and is more accurate and repeatable. The corresponding rabbit model of traumatic complex urethral stricture simulates the real complex clinical conditions. This animal model provides a standardized platform for clinical researches on treating traumatic injuries to the urinary system.

Comparison of a biodegradable ureteral stent versus the traditional double-J stent for the treatment of ureteral injury: an experimental study.

Ureteral injury remains a major clinical problem; here we developed a biodegradable ureteral stent and compared its effectiveness with a double-J stent for treating ureteral injury. Eighteen dogs with injured ureters were subdivided into two groups. In group A, one injured ureter was treated with a biodegradable stent, whereas only end-to-end anastomosis was performed on the other side. In group B, one injured ureter was treated with a biodegradable stent, while a double-J stent was used on the other side. Intravenous urography, radioactive renography, histological examinations, scanning electron microscopy (SEM) and elemental composition analysis were performed at 40, 80 and 120 days postoperatively. Results showed that the biodegradable stent could effectively prevent hydronephrosis and hydroureter secondary to ureteral injury. Moreover all biodegradable stents gradually degraded and discharged completely in 120 days. SEM and elemental composition analysis of the surface of the double-J stent confirmed calcification at 80 days and calcific plaque at 120 days, while no signs of calcification were found in the biodegradable stent group. Histological studies found no difference between the biodegradable stented ureters and double-J stented ureters. It is concluded that the biodegradable ureteral stent was more advantageous than the double-J stent for treating ureteral injury in a canine model.

New ureteral scaffold constructed with composite poly(L-lactic acid)-collagen and urothelial cells by new centrifugal seeding system.

A tissue-engineered ureteral scaffold was constructed with composited poly L-lactic acid (PLLA)-collagen endoluminal stent and uroepithelial cells (UECs) using a new seeding system. The electrospun PLLA-collagen nanofibrous mesh was seeded efficiently with human ureteral epithelial cells using a modified centrifugal seeding device. The cellular nanofibrous mesh was then wound around a spiral endoluminal stent to form a cellular composited PLLA-collagen ureteral scaffold. The cellular ureteral scaffold was subcutaneously implanted into nude mice. Cell attachment, distribution, and viability in vitro were investigated along with the cell fate in vivo. (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay showed that scaffolds seeded with centrifugal method had higher cellular activity than scaffolds seeded with static method (p < 0.05), and the metabolic activity per cell had no significant differences between the two methods (p > 0.05). Histologic analysis showed that the entrapped UECs remained in the scaffolds after 2 wk of implantation. The results of the study indicated that the composited PLLA-collagen endoluminal stent could serve as alternative cell carrier for tissue engineering ureter. In addition, the new modified centrifugal seeding system allowed rapid homogeneous distribution of cells onto the nanofibrous mesh, which will be useful to ureteral reconstruction.

A surface-modified biodegradable urethral scaffold seeded with urethral epithelial cells.

BACKGROUND: Efficient cell adhesion and proliferation is a central issue in cell-based tissue engineering, which offers great promise for repair of urethral defects or strictures. This study evaluated the adhesion and growth of rabbit uroepithelium on a surface-modified three-dimensional poly-L-lactic acid (PLLA) scaffold. METHODS: Urethral mucosa were harvested from male New Zealand rabbits and the urothelium were dissociated and then cultured. Immunocytochemistry on cultured uroepithelium for pancytokeratin and uroplakin II and TE-7 confirmed pure populations. After in vitro proliferation, cells were seeded onto a surface-modified urethral scaffold with non-knitted filaments. The morphology and viability of the cells were examined by immunohistochemical and fluorescence staining. Inverted and scanning microscopes were used to document cell growth and adhesion. RESULTS: Three to five days after primary culture, the uroepithelial cells gradually became confluent, assuming a cobblestone pattern. The filaments of the urethral scaffold had excellent biocompatibility and allowed growth of the uroepithelium, without affecting viability. The uroepithelial cells adhered to and grew well on the scaffold. After 3 - 7 days, the cells grew vigorously and meshes of the scaffold were full of uroepitheliums. CONCLUSIONS: The surface-modified urethral scaffold with non-knitted filaments allows the growth of uroepithelium and can serve as a carrier for the tissue engineering of urethra.

Stenotrophomonas maltophilia resistance to trimethoprim/sulfamethoxazole mediated by acquisition of sul and dfrA genes in a plasmid-mediated class 1 integron.

Stenotrophomonas maltophilia is becoming a more and more common cause of infections. In this study, the minimal inhibitory concentrations of trimethoprim/sulfamethoxazole (SXT), ceftazidime, minocycline, levofloxacin, chloramphenicol and ticarcillin/clavulanic acid were determined and the distribution of integrons and sul1, sul2 and dfrA genes was investigated in 102 S. maltophilia isolates collected from patients treated in 31 hospitals in Anhui, China, in the month of September in 2006-2008. The rate of resistance to SXT was up to 30.4%, and 64.7% of isolates were class 1 integron-positive. Sequencing data revealed the following novel gene cassettes embedded in class 1 integrons: dfrA17-aadA5; dfrA12-aadA2; aacA4-catB8-aadA1; aadB-aac(6')-II-bla(CARB-8); and arr-3-aacA4. This is the first report of the gene cassettes dfrA17-aadA5 and dfrA12-aadA2 and of sul2 genes in SXT-resistant S. maltophilia isolates in China. None of the SXT-susceptible S. maltophilia isolates were positive for sul2 or dfrA gene products by polymerase chain reaction (PCR), but PCR products for sul1 were detected in 27 SXT-susceptible and 25 SXT-resistant isolates. The findings from this study indicate that the sul1 gene, in combination with dfrA17 and dfrA12 gene cassettes and sul2 genes located within a 7.3kb plasmid, lead to a high rate of SXT resistance and also confirm the need for ongoing resistance surveillance.

Introduction to biodegradable polylactic acid ureteral stent application for treatment of ureteral war injury.

OBJECTIVE: • To study the operability and effectiveness of a biodegradable ureteral stent for clinical treatment of ureteral war injury using a canine model. MATERIALS AND METHODS: • A device was designed and employed to generate firearm fragment wounds in unilateral ureters (on randomly chosen sides) of nine beagles (Group A). The wounded ureters were then debrided and sutured. • Intravenous pyelography (IVP) and radioactive renography were performed 40, 80 and 120 days postoperatively. In Group B, firearm fragment wounds were made to the bilateral ureters in nine beagles. A polylactic acid stent was placed unilaterally (on a randomly chosen side) whereas the ureter on the other side was debrided and sutured without stenting. • Both IVP and radioactive renography were performed 40, 80 and 120 days postoperatively. The operability and effectiveness of the biodegradable ureteral stent were studied thereafter. RESULTS: • In Group A, hydronephrosis and hydroureter occurred and worsened postoperatively on the wounded sides in all nine beagles. The ratio of the renal partial concentration indices (RPCI) between the kidneys (unwounded side : wounded side) increased. • The ratio of the kidney washout half-time between the kidneys (unwounded side : wounded side) decreased. In Group B, neither hydronephrosis nor hydroureter was found postoperatively in the stented ureters but both occurred in the unstented ureters in all nine beagles. • The ratio of RPCI between kidneys (stented side : unstented side) increased whereas the kidney washout half-time ratio between the stented and unstented sides decreased. Differences were significant. CONCLUSION: • In Group A, the new canine model for firearm fragment wounds was tested and proved to be operable and effective. In Group B, hydronephrosis and hydroureter were effectively prevented in ureters by biodegradable stent placement compared with the non-stented ureters where hydronephrosis and hydroureter occurred. The renal concentration capacity was effectively protected and the half-time of kidney washout was shortened.

[An investigation of Gram-positive bacteria infection in an intensive care unit during 6 years].

OBJECTIVE: To retrospectively investigate the risk factors, distribution, antibiotic resistance of infection with Gram-positive (G+) bacteria in an intensive care unit (ICU), so as to provide the reference for clinical prevention and treatment. METHODS: A retrospective analysis of clinical data of 83 patients with G+ bacteria infection in ICU from January 2003 to December 2008 was done. RESULTS: Of the 125 strains of G+ bacteria from 83 patients, Staphylococcus was the main organism (63.2%, 79/125). The prognosis of the patient was related with surgical operation (chi2=9.107, P=0.003), gastric intubation (chi2=4.053, P=0.044), complication (chi2 5.908, P=0.015) and the use of immunosuppressant (chi2=5.761, P=0.016). Multi-bacterial infection was related with surgery (chi2=8.847, P=0.003) and tracheostomy (chi2=10.445, P=0.001). The antibiotic susceptibility test in vitro showed that G+ bacteria displayed multi-resistance to antibiotics, but all of G+ bacteria were sensitive to vancomycin (resistance rate was 0). CONCLUSION: Staphylococcus was the most common pathogen of G+ bacterial infection in ICU. Further surveillance of bacterial resistance is warranted in ICU, and antimicrobial drugs should be used according to the result of susceptibility test. Taking account of the antibiotic resistance and risk factors of G+ bacteria infection in ICU, the infection could be controlled and the death rate could be cut down when appropriate measures are taken.

[Proteomics study of intestinal mucosa after ischemic preconditioning against intestinal ischemic reperfusion injury in rats].

OBJECTIVE: To identify associated proteins involved in the molecular response of ischemic preconditioning (IPC) against intestinal ischemia/reperfusion (II/R) in the intestinal mucosa of rats. METHODS: Sixteen SD rats were randomly divided into II/R and IPC groups. II/R injury in rats was produced by clamping superior mesenteric artery for 60 min followed by 60 min reperfusion. IPC was elicited by 20 min ischemia and 5 min reperfusion before index ischemia. The intestinal mucosa was scratched immediately after 60 min of reperfusion and total proteins were separated by immobilized pH gradient (IPG) based on two-dimensional gel electrophoresis (2-DE). The differentially expressed proteins were analyzed using Image Master 2D Elite 5.0 image analysis software and identified by MALDI-TOF-MS. The biological information of these proteins was searched in the database of these peptide mass finger-printing (PMF). Western blotting and RT-PCR were used to validate the differentially expressed proteins. RESULTS: Image analysis revealed that averages of 1404+/-20 and 1338+/-20 were detected in II/R and IPC groups. A total of 10 spots yielded good spectra, and 8 spots matched with known proteins after database searching. These proteins were mainly involved in anti-oxidation, inhibiting apoptosis and energy metabolism. Western blot confirmed up-regulation of aldehyde dehydrogenase and RT-PCR confirmed up-regulation of aldose reductase in IPC group. CONCLUSION: The clues provided by comparative proteome strategy will shed light on molecular mechanisms of IPC against II/R injury.

Immediate postconditioning during reperfusion attenuates intestinal injury.

OBJECTIVE: To test the hypothesis that immediate but not delayed ischemic postconditioning (IPo) during reperfusion attenuates intestinal injury, and that ischemic preconditioning (IPC) and IPo may confer synergy in intestinal protection. DESIGN AND SETTING: Prospective laboratory animal study with concurrent control. SUBJECTS: Adult Sprague-Dawley rats. INTERVENTIONS: Intestinal ischemia/reperfusion (II/R) injury in rats was produced by clamping superior mesenteric artery for 60 min followed by 60 min reperfusion; IPC was elicited by 10 min ischemia and 10 min reperfusion before index ischemia; IPo was performed by three cycles of 30 s reperfusion and 30 s ischemia initiated either immediately at the onset of reperfusion (IPo) or after reperfusion for 3 min (delayed-IPo). Combination of IPC and IPo was performed by combining both protocols. MEASUREMENTS AND MAIN RESULTS: Intestinal ischemia/reperfusion resulted in significant intestinal injury evidenced as significant increase in Chiu's scores and wet-to-dry intestine weight ratio accompanied with increases in plasma levels of tumor necrosis factor-alpha and interleukin-6, as well as increases in the intestinal tissue lipid peroxidation product malonediadehyde and myeloperoxidase activity as compared to control animals (all P < 0.05). All these changes were significantly attenuated either by IPC or IPo or their combination (P < 0.05), and not by delayed-IPo (P > 0.05). IPC and IPo showed synergistic protection compared with either protocol alone. CONCLUSION: Ischemic postconditioning reduces intestinal injury, in part, by inhibiting oxidative injury, neutrophils filtration and proinflammatory response. The early period of reperfusion is critical to intestinal protection by IPo, and intestinal protection with IPo can be enhanced by IPC.

Heterogeneity of bla(IND) metallo-beta-lactamase-producing Chryseobacterium indologenes isolates detected in Hefei, China.

This study investigated the phenotypic and genetic properties of 28 clinical isolates of metallo-beta-lactamase (MBL)-producing Chryseobacterium indologenes recovered from a university hospital. Twenty isolates were confirmed to carry a bla(IND) gene. Among them, 9 isolates were confirmed to carry the IND-1 gene, 10 contained the IND-2 gene and 1 had bla(IND-3) alleles. One strain (No. 7) confirmed to be carrying the bla(IND-1) gene was susceptible to imipenem and was negative in phenotypic methods. The data revealed that the antimicrobial resistance patterns of C. indologenes harbouring MBL genes are remarkably distinct. Two specific types of MBL genes, bla(IND-1) and bla(IND-2), were identified to be the major genotype for C. indologenes isolated from Hefei, China.

[Detection of the new type of aminoglycoside acetyltransferase gene in Enterobacter cloacae isolates].

OBJECTIVE: To investigate the prevalence of aac(6')-Ib-cr gene in Enterobacter cloacae isolates. METHODS: PCR and sequencing were performed on 81 strains of Enterobacter cloacae isolated clinically in Anhui province to identify aac (6')-IB-cr gene. Disk diffusion method was used to test the susceptibility of the Enterobacter cloacae isolates with aac (6')-Ib-cr gene to fluoroquinolones, aminoglycosides, and other antimicrobial agents. AmpC and extended-spectrum beta-lactamases (ESBLs) were detected by modified three-dimensional extract test, and the molecular typing was analyzed by ERIC-PCR. RESULTS: Aac (6')-Ib-cr gene was identified in 3 (3.7%) of the 81 Enterobacter cloacae isolates with different ERIC-PCR patterns. The isolates with aac (6')-Ib-cr gene were resistant to fluoroquinolones, aminoglycosides, chloramphenicol, ampicillin, cefoxitin, and second and third generation cephalosporins. Two of the 3 isolates produced AmpC and ESBLs, and 1 isolate produced only ESBLs. CONCLUSION: Aac (6')-Ib-cr gene is prevalent in Enterobacter cloacae isolates with resistance to most of antimicrobial agents and no clone spread in found in them.