A Case of Immediate Anastomotic Leakage After Low Anterior Resection for Rectal Cancer.

A man in his seventies was referred to our hospital for radical therapy for advanced rectal cancer with multiple liver metastases. A colonic stent had already been placed in his rectum at the previous hospital because of malignant colorectal obstruction, so our therapeutic strategy was to perform systematic chemotherapy after resection of the primary tumor. Laparoscopic low anterior resection with a covering stoma was performed under general anesthesia. At about one hour after the surgery, the patient had sudden abdominal pain with watery diarrhea, and a similar discharge from his drainage tube. We suspected peritonitis caused by bowel perforation and emergency surgery was performed. The operative findings showed that his peritonitis was caused by anastomotic leakage from the rectum. Radical lavage of the abdominal space and reconstruction of colostomy was performed. The patient gradually recovered and we were able to start systematic chemotherapy at one month after the surgery. Anastomotic leakage immediately after anterior resection caused by watery diarrhea is rare, and it may be concerned with several issues. The covering stoma is intended to stop anastomotic leakage but it cannot prevent all cases of leakage especially when obstruction is present. We recommend that preventive measures be taken against anastomotic leakage, including intraoperative leakage tests or anal decompression tube placement.

Investigation of the susceptibility trends in Japan to fluoroquinolones and other antimicrobial agents in a nationwide collection of clinical isolates: A longitudinal analysis from 1994 to 2016.

The susceptibilities of clinical isolates to fluoroquinolones and other antimicrobial agents were surveyed to obtain an accurate understanding of trends in incidence and antimicrobial resistance. The samples were collected from across Japan, biennially or triennially, between 1994 and 2016 and a defined level of resistance to fluoroquinolone was determined. Streptococcus pneumoniae, Streptococcus pyogenes and Haemophilus influenzae exhibited stable and high rates of susceptibility to fluoroquinolones over the period examined. For methicillin-resistant Staphylococcus aureus the rate of resistance to levofloxacin and ciprofloxacin was 81.3-93.5% and 83.2-94.2%, respectively, which was markedly higher than that of methicillin-susceptible S. aureus, while sitafloxacin-resistant methicillin-susceptible and methicillin-resistant S. aureus were isolated at 0.3-0.7% and 16.9-36.5%, respectively. The rate of levofloxacin or ciprofloxacin-resistant Escherichia coli increased from around 2-3% between 1994 and 1998 to around 35% in 2016, but the rate of fluoroquinolone-susceptible Klebsiella pneumoniae stayed high at over 94.6% during the study period. Although no fluoroquinolone-resistance in clinical isolates of Salmonella spp. was detected from 1994 to 2002, the resistance rate increased slightly after 2004 and reached to 1.9%-4.7% in 2016. The rate of fluoroquinolone-susceptible Pseudomonas aeruginosa isolated from urinary tract and respiratory tract infections improved during the period examined from 41.8-67.0% to 91.2-94.2%, and from 78.9-88.5% to 90.1-94.6%, respectively. Against Acinetobacter spp., the susceptibility rate of fluoroquinolones was almost constant at around 90%, but one multidrug-resistant isolate was detected in 2013. Overall, the susceptibility to fluoroquinolones was maintained over 20 years against tested bacteria except for MRSA and E. coli.

Role of interleukin-17 in a murine community-associated methicillin-resistant Staphylococcus aureus pneumonia model.

Interleukin (IL)-17 is a key member of the Th17 cytokines and has been reported to be involved in the pathomechanisms underlying various diseases, including infectious diseases. Infections with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) have garnered worldwide attention, and the representative USA300 strain is known to cause pneumonia in healthy people, which can be lethal. However, little is known about the role of IL-17 in CA-MRSA pneumonia. In this study, we investigated the role of IL-17 in a CA-MRSA pneumonia animal model. Mortality was higher and occurred at an earlier stage of infection in the IL-17A-knockout mice than in the wild-type (P < 0.01) and IL-17A/F-knockout mice (P < 0.05); however, no significant difference in the intrapulmonary bacterial counts was observed among the three groups of mice. Moreover, the IL-17A-knockout group showed significantly higher levels of IL-17F and granulocyte-colony stimulating factor (G-CSF) and a significantly higher neutrophil count in the bronchoalveolar lavage fluid than the other groups. These results confirmed that G-CSF expression significantly increased, and significant neutrophilic inflammation occurred under conditions of IL-17A deficiency in the murine CA-MRSA pneumonia model.

Azithromycin Modulates 3',5'-cyclic Diguanylic Acid Signaling in Pseudomonas aeruginosa.

Macrolides have been reported to exert a variety of effects on both host immunomodulation and repression of bacterial pathogenicity. In this study, we report that the 3',5'-cyclic diguanylic acid (c-di-GMP) signaling system, which regulates virulence in Pseudomonas aeruginosa, is affected by the macrolide azithromycin. Using DNA microarray analysis, we selected a gene encoding PA2567 related to c-di-GMP metabolism that was significantly affected by azithromycin treatment. Expression of the PA2567 gene was significantly repressed by azithromycin in a time- and dose-dependent manner, whereas no difference in PA2567 gene expression was observed in the absence of azithromycin. In-frame deletion of the PA2567 gene affected both virulence factors and the quorum-sensing system, and significantly decreased total bacteria in a mouse pneumonia model compared to the wild-type strain (P < 0.05). These results suggest that macrolides possess the ability to modulate c-di-GMP intracellular signaling in P. aeruginosa.

Interstitial pneumonia in a patient treated with TAS-102 for metastatic colorectal cancer: a case report.

BACKGROUND: TAS-102, a new treatment option for patients with metastatic colorectal cancer that is refractory or intolerant to standard therapies, has been improving survival with acceptable tolerability and adverse events. Adverse hematological events associated with TAS-102 treatment were extensively profiled in the RECOURSE trial, but pulmonary toxicities associated with TAS-102 therapy are distinctly uncommon. In a recent early post-marketing phase vigilance on TAS-102 in Japan, seven cases of pulmonary disease were reported, but patient follow-up in this study was incomplete. Here, we present the first case of interstitial lung disease occurring in association with TAS-102 treatment. CASE PRESENTATION: A 57-year-old Japanese man who had previously received two standard treatments was admitted in 2014, at which time we administered TAS-102 (110 mg/day) as a third-line chemotherapy. He was safely treated with TAS-102 for the first planned cycle; however, approximately 4 days after receiving the second cycle of TAS-102, he complained of high fever and subsequent dyspnea with severe hypoxemia and went to the emergency room. A chest X-ray revealed diffuse coarse reticular shadows with ground-glass opacity on both lungs. Furthermore, a chest computed tomography scan showed thickening of the bronchovascular bundles with extensive ground-glass opacification and pleural effusions in both lung fields. In addition, a peripheral blood lymphocyte stimulation test with TAS-102 showed higher values compared with control samples. Consequently, we suspected drug-induced interstitial pneumonia, and discontinued treatment. Our patient was given an initial administration of high-dose methylprednisolone (1000 mg/day) for 3 days and oxygen. Our patient was discharged with oral prednisolone (20 mg/day) and improved symptomatically and radiologically. CONCLUSIONS: These findings suggest that interstitial pneumonia is a rare complication of TAS-102 chemotherapy, but the possibility of interstitial pneumonia should always be considered when a patient presents with a respiratory disorder while undergoing TAS-102 systemic chemotherapy. Prompt discontinuation of TAS-102 and treatment with high-dosage corticosteroids is needed to avoid exacerbating respiratory symptoms.

[Surveillance of in vitro susceptibilities to levofloxacin and various antibacterial agents for 11,762 clinical isolates obtained from 69 centers in 2013].

Antimicrobial susceptibility testing has been conducted continuously as postmarketing surveillance of levofloxacin (LVFX) since 1994. The present survey was undertaken to investigate in vitro susceptibilities of bacteria to 33 selected antibacterial agents, focusing on fluoroquinolones (FQs), using 11,762 clinical isolates for 19 species collected from 69 centers during 2013 in Japan. The common respiratory pathogens Streptococcus pyogenes, Streptococcus pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae continue to show a high susceptibility to FQs, while the percentage of macrolide-resistant S. pneumoniae was markedly increased to around 80%. With H. influenzae, the percentage of ß-lactamase-negative ampicillin-resistant isolates had been increasing continuously from 2002, but no increase was observed from 2010 to 2013 (25.8% in 2002, 40.0% in 2004, 50.1% in 2007, 57.9% in 2010, and 57.1% in 2013). Most strains of Enterobacteriaceae showed a high susceptibility to FQs, but the isolation frequency of levofloxacin-resistant Escherichia coli including intermediate resistance was 34.4%, showing a continuous increase. Another Enterobacteriaceae member, Klebsiella pneumoniae, showed low resistance to FQs in contrast with E. coli. Regarding methicillin-resistant Staphylococcus aureus (MRSA), the percentage of FQ-susceptible isolates was low at 15.8-18.0%, with the exception of 55.3% susceptibility to sitafloxacin. On the other hand, methicillin-susceptible S. aureus (MSSA) isolates showed high susceptibility to FQs, at 87.0-99.3%. With Enterococcusfaecium, the percentage of FQ-susceptible isolates was 6.8-24.7%. The percentage of FQ-susceptible Pseudomonas aeruginosa was 83.4-89.3% among isolates derived from urinary tract infections (UTIs), while that from respiratory tract infections (RTIs) was 88.1-93.7%. This was summarized as susceptibility to FQs over 80% in both infections. A continuous decrease in FQ-resistant P. aeruginosa was noted, especially among isolates from UTIs. Regarding multidrug-resistant P aeruginosa, the percentage has been decreasing continuously since 2007 and was 1.6% from UTIs and 0% from RTI in this survey. Acinetobacter spp. showed high susceptibility to FQs. The percentage of imipenem-resistant Acinetobacter spp. was 2.7% (14 isolates) and that of multidrug-resistant was 0.2% (1 isolate). In Neisseria gonorrhoeae, ceftriaxone (CTRX) had been showing 100% susceptibility until 2007, but CTRX-resistant strains have been detected in both 2010 and this survey. In conclusion, the resistance of methicillin-resistant staphylococci, E. faecium, N. gonorrhoeae, and E. coli to the FQs, which have been used clinically for over 20 years, was shown to be 30% or more (31.7-87.1%) in the present surveillance regarding susceptibility. These results were similar to those from previous surveillance, and no species that started to show significant resistance to FQs were identified in the present surveillance. Regarding other bacterial species, susceptibility to ciprofloxacin less than 80% was observed in some, while susceptibility to other FQs was maintained at a high level, at 80% or more.

Stability of Novel Siderophore Cephalosporin S-649266 against Clinically Relevant Carbapenemases.

To better understand the antibacterial activity of S-649266 against carbapenemase producers, its stability against clinically relevant carbapenemases was investigated. The catalytic efficiencies (kcat/Km) of IMP-1, VIM-2, and L1 for S-649266 were 0.0048, 0.0050, and 0.024 µM(-1) s(-1), respectively, which were more than 260-fold lower than that for meropenem. Only slight hydrolysis of S-649266 against KPC-3 was observed. NDM-1 hydrolyzed meropenem 3-fold faster than S-649266 at 200 µM.

Molecular analysis of the integrons of metallo-ß-lactamase-producing Pseudomonas aeruginosa isolates collected by nationwide surveillance programs across Japan.

BACKGROUND: We investigate the evolving molecular epidemiology of metallo-ß-lactamase (MBL)-producing Pseudomonas aeruginosa isolates collected in a 100 institution, nationwide surveillance study in Japan from 2004 to 2006. RESULTS: MBL-producers were detected in 23/996 isolates (2.3%) in 2004 and 21/992 (2.1%) in 2006. Antimicrobial resistance (specifically, carbapenem resistance) rates between two periods did not differ significantly. MBL-producers were more prevalent in urinary tract isolates. bla IMP-1 group was the most predominant (38 isolates, 80%), followed by 3 bla IMP-7, 2 bla IMP-11 group, and 1 bla VIM-1. All MBL genes were identified in 16 different class 1 integrons, most of which were novel to INTEGRALL database. A total of 17 isolates of sequence type (ST) 235, a recognized worldwide drug-resistant lineage, were distributed in 5 geographic regions across Japan. ST235 isolates included a sublineage associated with In113-like integron. ST357 was identified in 14 isolates, 9 of which harboring a sole bla IMP-1 gene cassette (In994) were recovered from Chugoku region in 2004. ST357 isolates with bla IMP-11 group or ST235 with bla IMP-7 emerged in 2006. We also report for the first time the presence of novel fosI gene cassette in strains other than Mycobacterium spp. CONCLUSIONS: Our data give an important "snapshot" of the molecular characteristics and dynamics of MBL-producing lineages in P. aeruginosa in Japan. The significant association of specific genotypes and integrons implies that dissemination and transmission of the preexisting resistant lineage, rather than horizontal gene transfer in situ, might largely explain their endemicity.

[Stevens-Johnson syndrome induced by regorafenib in a patient with progressive recurrent rectal carcinoma].

A 55-year-old man with rectal carcinoma underwent lower anterior resection. Eight years after surgery, multiple metastases were detected in the liver, lung, and abdominal lymph nodes. The metastatic cancers were resistant to standard chemotherapy. Thus, regorafenib was administered to the patient. The patient presented symptoms of Stevens-Johnson syndrome (SJS) nine days after regorafenib administration, and hence, treatment was terminated. To treat SJS, he received oral and topical steroid therapies. SJS is an important adverse event that hinders the continuation of regorafenib treatment. Thus, it is necessary to continually check the patient's skin condition carefully, especially at early stages of treatment. To our knowledge, this is the first report of SJS arising during the course of regorafenib treatment.

Fecoflowmetric analysis of anorectal motor function in postoperative anal-preserving surgery patients with low rectal cancer comparison with the wexner score and anorectal manometry.

The aim of this study was to elucidate whether fecoflowmetry (FFM) could evaluate more detailed evacuative function than anorectal manometry by comparing between FFM or anorectal manometric findings and the clinical questionnaires and the types of surgical procedure in the patients who received anal-preserving surgery. Fifty-three patients who underwent anal-preserving surgery for low rectal cancer were enrolled. The relationships between FFM or the manometric findings and the clinical questionnaires and the types of procedure of anal-preserving surgery were evaluated. There were significant differences between FFM markers and the clinical questionnaire and the types of the surgical procedure, whereas no significant relationship was observed between the manometric findings and the clinical questionnaire and the types of the surgical procedure. FFM might be feasible and useful for the objective assessment of evacuative function and may be superior to manometry for patients undergoing anal-preserving surgery.

Loop-mediated isothermal amplification assay for 16S rRNA methylase genes in Gram-negative bacteria.

Using the loop-mediated isothermal amplification (LAMP) method, we developed a rapid assay for detection of 16S rRNA methylase genes (rmtA, rmtB, and armA), and investigated 16S rRNA methylase-producing strains among clinical isolates. Primer Explorer V3 software was used to design the LAMP primers. LAMP primers were prepared for each gene, including two outer primers (F3 and B3), two inner primers (FIP and BIP), and two loop primers (LF and LB). Detection was performed with the Loopamp DNA amplification kit. For all three genes (rmtA, rmtB, and armA), 10(2) copies/tube could be detected with a reaction time of 60 min. When nine bacterial species (65 strains saved in National Institute of Infectious Diseases) were tested, which had been confirmed to possess rmtA, rmtB, or armA by PCR and DNA sequencing, the genes were detected correctly in these bacteria with no false negative or false positive results. Among 8447 clinical isolates isolated at 36 medical institutions, the LAMP method was conducted for 191 strains that were resistant to aminoglycosides based on the results of antimicrobial susceptibility tests. Eight strains were found to produce 16S rRNA methylase (0.09%), with rmtB being identified in three strains (0.06%) of 4929 isolates of Enterobacteriaceae, rmtA in three strains (0.10%) of 3284 isolates of Pseudomonas aeruginosa, and armA in two strains (0.85%) of 234 isolates of Acinetobacter spp. At present, the incidence of strains possessing 16S rRNA methylase genes is very low in Japan. However, when Gram-negative bacteria showing high resistance to aminoglycosides are isolated by clinical laboratories, it seems very important to investigate the status of 16S rRNA methylase gene-harboring bacilli and monitor their trends among Japanese clinical settings.

[Nationwide surveillance of parenteral antibiotics containing meropenem activities against clinically isolated strains in 2012].

The nationwide surveillance of antibacterial susceptibility to meropenem (MEPM) and other parenteral antibiotics against clinical isolates during 2012 in Japan was conducted. A total of 2985 strains including 955 strains of Gram-positive bacteria, 1782 strains of Gram-negative bacteria, and 248 strains of anaerobic bacteria obtained from 31 medical institutions were examined. The results were as follows; 1. MEPM was more active than the other carbapenem antibiotics tested against Gram-negative bacteria, especially against enterobacteriaceae and Haemophilus influenzae. MEPM was also active against most of the species tested in Gram-positive and anaerobic bacteria, except for multi-drug resistant strains including methicillin-resistant Staphylococcus aureus (MRSA). 2. Of all species tested, there were no species, which MIC90 of MEPM was more than 4-fold higher than those in our previous studies in 2009 or 2006. Therefore, the tendency to increase in antimicrobial resistance rates was not observed. 3. MEPM resistance against Pseudomonas aeruginosa was 17.8% (56/315 strains). Compared to our previous results, it was the lowest than that in 2006 and 2009. 4. Carbapenem-resistant Klebsiella pneumoniae, and multi-drug-resistant Acinetobacter species, which emerged in worldwide, were not observed. 5. The proportion of extended-spectrum beta-lactamase (ESBL) strains was 6.2% (59/951 strains) in enterobacteriaceae, which increased compared with that of our previous studies in 2009 or before. Whereas, the proportion of metallo-beta-lactamase strains was 1.6% (5/315 strains) in P. aeruginosa, which was stable. In conclusion, the results from this surveillance suggest that MEPM retains its potent and broad antibacterial activity and therefore is a clinically useful carbapenem for serious infections treatment at present, 17 years passed after available for commercial use in Japan.

Spread of CTX-M-15 extended-spectrum ß-lactamase-producing Escherichia coli isolates through household contact and plasmid transfer.

We document the household spread of extended-spectrum ß-lactamase-producing Escherichia coli. One isolate belonged to sequence type 1193 and caused urinary tract infection in a 4-month-old female, and the other isolate belonged to sequence type 131 and colonized three family members, including the index patient. These isolates carried similar Inc-I1-Iγ plasmids, harboring blaCTX-M-15.

Identification of high-risk factors as indicators for adjuvant therapy in stage II colon cancer patients treated at a single institution.

Although post-operative adjuvant chemotherapy (ACT) is only recommended for patients with stage II colon cancer who are at a high risk of recurrence, the definition of high risk remains unclear. The present study aimed to identify the risk factors for recurrence, which may also be indicators for adjuvant therapy, using a retrospective analysis of clinicopathological data obtained from stage II colon cancer patients who had undergone a curative resection. The present study also investigated the effects of ACT in patients who displayed the risk factors for recurrence. Univariate and multivariate analyses of the data collected from 377 stage II colon cancer patients, treated at Kurume University Hospital (Fukuoka, Japan) between 1982 and 2005, was conducted in order to determine and compare the risk factors for recurrence between the 163 patients who had undergone adjuvant therapy and the 214 patients who had not undergone adjuvant therapy. The risk factors for recurrence in patients who had not undergone adjuvant therapy were a serum carcinoembryonic antigen (CEA) level that was twice the cut-off value and pre-operative bowel obstruction. Adjuvant therapy provided no benefit to patients who presented with neither risk factor, but significantly decreased the recurrence rate in patients presenting with one or both risk factors. Based on these findings, serum CEA levels of twice the cut-off value and pre-operative bowel obstruction were proposed as indicators in the assessment for adjuvant chemotherapy following a curative resection for stage II colon cancer. These results warrant further clinical study of ACT in patients with one or both risk factors.

Protective effect of procysteine on Acinetobacter pneumonia in hyperoxic conditions.

OBJECTIVES: Ventilator-associated pneumonia (VAP) is an important cause of morbidity and mortality in critical care settings. Acinetobacter has become a leading cause of VAP. In particular, the appearance and spread of multidrug-resistant Acinetobacter is of great concern. In this study, we examined the effect of the antioxidant procysteine on Acinetobacter murine pneumonia in hyperoxic conditions in order to simulate VAP. METHODS: Acinetobacter was administered intranasally to BALB/c mice kept in hyperoxic conditions. At designated timepoints, bacterial number, cytokine production and histopathological findings in the lungs were examined. The effects of procysteine on survival rates, lung bacterial burdens and the phagocytic activities of alveolar macrophages were evaluated. RESULTS: Drastic decreases in survival were observed when the infected mice were kept in hyperoxic conditions (P < 0.001). Significant differences in pulmonary bacterial number and neutrophil accumulation were observed between mice kept in hyperoxic or normoxic conditions on day 3. Although all mice infected with Acinetobacter spp. and kept in hyperoxic conditions died by day 3, procysteine treatment significantly improved survival (60% survival on day 7, P < 0.01). Procysteine treatment decreased the lung bacterial burden on days 2 and 3. Finally, improved uptake of FITC-labelled beads by alveolar macrophages from mice treated with procysteine and kept in hyperoxic conditions was noted. CONCLUSIONS: These results suggest that hyperoxia increases mortality in mice with Acinetobacter pneumonia and that procysteine improves survival by increasing the phagocytic activity of alveolar macrophages in mice kept in hyperoxic conditions.

Characterization of qnrB-like genes in Citrobacter species of the American Type Culture Collection.

Among five American Type Culture Collection (ATCC) Citrobacter strains, qnrB60 in Citrobacter freundii ATCC 6879, an isolate from the preantibiotic era, and qnrB61 in Citrobacter braakii ATCC 51113(T), a type strain belonging to the C. freundii complex, were identified. Meanwhile, a truncated qnrB-like pseudogene was identified in C. freundii ATCC 8090(T) and ATCC 43864. No qnrB-like sequence was found in Citrobacter koseri ATCC 27028(T). These findings underscore the close relationship between this species and qnrB.

Molecular characterization of extraintestinal Escherichia coli isolates in Japan: relationship between sequence types and mutation patterns of quinolone resistance-determining regions analyzed by pyrosequencing.

Infection from fluoroquinolone-resistant Enterobacteriaceae is an increasing health problem worldwide. In the present study, we developed a pyrosequencing-based high-throughput method for analyzing the nucleotide sequence of the quinolone resistance-determining regions (QRDRs) of gyrA and parC. By using this method, we successfully determined the QRDR sequences of 139 out of 140 clinical Escherichia coli isolates, 28% of which were nonsusceptible to ciprofloxacin. Sequence results obtained by the pyrosequencing method were in complete agreement with those obtained by the Sanger method. All fluoroquinolone-resistant isolates (n = 35; 25%) contained mutations leading to three or four amino acid substitutions in the QRDRs. In contrast, all isolates lacking a mutation in the QRDR (n = 81; 57%) were susceptible to ciprofloxacin, levofloxacin, and nalidixic acid. The qnr determinants, namely, the qnrA, qnrB, and qnrS genes, were not detected in the isolates, and the aac(6')-Ib-cr gene was detected in 2 (1.4%) of the isolates. Multilocus sequence typing of 34 randomly selected isolates revealed that sequence type 131 (ST131) (n = 7; 20%) is the most prevalent lineage and is significantly resistant to quinolones (P < 0.01). The genetic background of quinolone-susceptible isolates seemed more diverse, and interestingly, neighboring STs of ST131 in the phylogenetic tree were all susceptible to ciprofloxacin. In conclusion, our investigation reveals the relationship between fluoroquinolone resistance caused by mutations of QRDRs and the population structure of clinical extraintestinal E. coli isolates. This high-throughput method for analyzing QRDR mutations by pyrosequencing is a powerful tool for epidemiological studies of fluoroquinolone resistance in bacteria.

Use of culture-independent analysis to reveal alteration of intestinal microflora by heat-killed Lactobacillus pentosus in a mouse model of endogenous sepsis.

In this study we evaluated alteration of intestinal microflora by terminal-restriction fragment length polymorphism (T-RFLP) analysis and quantitative PCR (qPCR) for specific microbes. The effects of orally administered heat-killed Lactobacillus pentosus strain b240 (HK-b240) in immunosuppressed mice with endogenous Pseudomonas aeruginosa sepsis was estimated. By T-RFLP analysis, 5 dominant operational taxonomic units (OTUs) including Bacteroides spp. (OTU460) and Lactobacillus spp. (OTU657) were consistently observed, irrespective of treatment, at all time points. A significantly higher population of segmented filamentous bacteria (SFB) was observed by qPCR after 3 weeks of HK-b240 administration; thereafter, the difference was not sustained during immunosuppression and progression of sepsis. Although not significant, Lactobacillus spp. accounted for a larger population in the HK-b240-treated group. In conclusion, this study demonstrated successful application of culture-independent assays for evaluating biological agents by detecting changes in microflora even if the protection was not sufficient to result in significant survival change.

Effects of slow-releasing colistin microspheres on endotoxin-induced sepsis.

Lipopolysaccharide (LPS) is a major contributing factor to endotoxic shock. Colistin specifically binds to LPS. However, it has the disadvantages that adverse reactions are common and it has a short half-life. To overcome these disadvantages, we prepared slow-releasing colistin microspheres and examined the efficacy of these colistin microspheres in a mouse model of endotoxin-induced sepsis. We prepared the colistin microspheres using poly-lactic-co-glycolic acid. For acute toxicity investigations, mice were overdosed with colistin sulfate or colistin microspheres. The group administered with colistin microspheres was associated with less acute toxicity and fewer nephrotoxic changes on histopathological examination compared to the group administered with colistin sulfate alone. For pharmacokinetic analysis, mice were subcutaneously administered with colistin microspheres or colistin sulfate alone. The plasma concentration of colistin was higher in the colistin microspheres group than in the colistin sulfate group at 12 and 24 h after administration. Moreover, mice were intraperitoneally injected with LPS and then immediately subcutaneously administered with blank microspheres, colistin microspheres or colistin sulfate alone. The levels of endotoxin in the sera and cytokine in the spleens were then measured. A significant reduction in the serum endotoxin level in the colistin microspheres group was observed at 24 h. The reduced endotoxin levels in the sera were correlated with the lower cytokine levels in the spleens of mice treated with colistin microspheres. Our results suggest that the use of colistin microspheres may help to maintain a higher colistin concentration in blood, reduce the levels of endotoxin and cytokines in endotoxin-induced sepsis, and lead to decreased toxicity.