A longitudinal study of Candida bloodstream infections in a Japanese university hospital: species distribution, drug susceptibility, clinical features, and mortality predictors.

We aimed to detect possible changes in Candida species distribution over time and to know the antifungal susceptibility profile of isolates obtained from patients with bloodstream infection (BSI) due to this pathogen. Risk factors associated with 30-day mortality were also assessed. We conducted a retrospective cohort study of patients diagnosed with Candida BSI at a Japanese university hospital from 2013 to 2021. The change in the distribution pattern of the Candida spp. isolated was examined by considering three successive sub-periods of 3 years each. Risk factors for 30-day mortality were determined using Cox regression analysis. In the entire study period, Candida albicans was the most frequent species (46.7%), followed by Candida glabrata (21.5%) and Candida parapsilosis (18.7%). There was no change in Candida species distribution comparing the three sub-periods analyzed. All isolates were susceptible to micafungin, and most were susceptible to fluconazole, except for C. glabrata. No isolates were resistant to amphotericin B or voriconazole. The overall 30-day mortality was 40.2%. Univariate analysis revealed an association between 30-day mortality and central venous catheter (CVC) removal at any time, high Pitt bacteremia score (PBS), and high Charlson comorbidity index (CCI). Multivariate Cox analysis found that high PBS was the only independent predictor of 30-day mortality; subsequent multivariate Cox regression demonstrated that early CVC removal significantly reduced 30-day mortality. Candida species distribution and antifungal susceptibility profile in our hospital remained similar from 2013 to 2021. Early CVC removal may improve candidemia outcomes.

Association of methicillin resistance with mortality of hospital-acquired Staphylococcus aureus bacteremia.

OBJECTIVE: Methicillin-resistant (MR) Staphylococcus aureus bacteremia (SAB) is associated with higher mortality rates than methicillin-susceptible (MS) SAB. This study assessed potential predictors of mortality and evaluated the association of methicillin resistance with mortality in patients with SAB. METHODS: We conducted a retrospective cohort study in patients with hospital-acquired SAB, from 2009 to 2018. Clinical features of patients with MR-SAB were compared with those of patients with MS-SAB and predictors of 30-day mortality were determined using Cox regression analysis. RESULTS: Among 162 patients, 56.8% had MR-SAB. Overall 30-day mortality was 19.1%; MR-SAB had higher mortality (25.0%) than MS-SAB (11.4%). Univariate analysis highlighted long-term hospitalization, prior antibiotics use, and delayed initiation of appropriate antibiotics as risk factors. Cox regression analysis showed that respiratory tract source, Pitt bacteremia score, Charlson comorbidity index, and appropriate antibiotic therapy within 24 hours were independently and significantly associated with 30-day mortality outcome. CONCLUSIONS: Methicillin resistance was not an independent risk factor for mortality in patients with SAB. Early, appropriate antibiotic treatment is an important prognostic factor.

Influence of UGT1A1 polymorphism on etoposide plus platinum-induced neutropenia in Japanese patients with small-cell lung cancer.

BACKGROUND: The association between UGT1A1 polymorphism and etoposide-induced toxicities is still not clear. The aim of this study was to assess the association between uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) gene polymorphism and severe hematologic toxicities in Japanese patients receiving etoposide plus platinum chemotherapy for small-cell lung cancer. METHODS: This retrospective analysis included patients with small-cell lung cancer who had received their first-line chemotherapy with etoposide plus cisplatin or carboplatin, between October 2008 and April 2018, at the University of Fukui Hospital. The relationship between UGT1A1 polymorphisms and first-cycle neutropenia as well as thrombocytopenia was evaluated. RESULTS: A total of 55 patients were enrolled. The incidence of grade 4 neutropenia during the first cycle of etoposide-based chemotherapy was higher in patients with homozygous (hmz) polymorphisms for UGT1A1*28 and *6 (*28/*28, *6/*6, and *6/*28) than in patients with wild-type (wt) (*1/*1) and heterozygous (htz) (*1/*28 and *1/*6) polymorphisms (88% vs 43% P = 0.03). The incidence of febrile neutropenia and grade 4 thrombocytopenia, however, was not significantly different. Multivariate analysis suggested that grade 4 neutropenia associated significantly with an hmz UGT1A1 genotype [odds ratio (OR) 11.3; P = 0.04] and administration of granulocyte colony-stimulating factor (G-CSF) before the neutrophil counts dropped to < 500 cells/µL (OR; P = 0.01). CONCLUSIONS: UGT1A1*28 and UGT1A1*6 mutations might be regarded as predictors for etoposide-induced grade 4 neutropenia.

The Inhibitory Effect of Ciprofloxacin on the ß-Glucuronidase-mediated Deconjugation of the Irinotecan Metabolite SN-38-G.

The enterohepatic recycling of a drug consists of its biliary excretion and intestinal reabsorption, which is sometimes accompanied by hepatic conjugation and intestinal deconjugation reactions. ß-Glucuronidase, an intestinal bacteria-produced enzyme, can break the bond between a biliary excreted drug and glucuronic acid. Antibiotics such as ciprofloxacin can reduce the enterohepatic recycling of glucuronide-conjugated drugs. In this study, we established an in vitro system to evaluate the ß-glucuronidase-mediated deconjugation of the irinotecan metabolite SN-38-G to its active SN-38 form and the effect of ciprofloxacin thereon. SN-38 formation increased in a time-dependent manner from 5 to 30 min. in the presence of ß-glucuronidase. Ciprofloxacin and phenolphthalein-ß-D-glucuronide (PhePG), a typical ß-glucuronidase substrate, significantly decreased SN-38-G deconjugation and, hence SN-38 formation. Similarly, the antibiotics enoxacin and gatifloxacin significantly inhibited the conversion of SN-38-G to SN-38, which was not observed for levofloxacin, streptomycin, ampicillin and amoxicillin/clavulanate. Ciprofloxacin showed a dose-dependent inhibitory effect on the ß-glucuronidase-mediated conversion of SN-38-G to SN-38 with a half-maximal inhibitory concentration (IC50 ) value of 83.8 µM. PhePG and ciprofloxacin afforded the inhibition in a competitive and non-competitive manner, respectively. These findings suggest that the reduction in the serum SN-38 concentration following co-administration of ciprofloxacin during irinotecan treatment is due, at least partly, to the decreased enterohepatic circulation of SN-38 through the non-competitive inhibition of intestinal ß-glucuronidase-mediated SN-38-G deconjugation.

Inhibitory effect of ciprofloxacin on ß-glucuronidase-mediated deconjugation of mycophenolic acid glucuronide.

The interaction between mycophenolate (MPA) and quinolone antibiotics such as ciprofloxacin is considered to reduce the enterohepatic recycling of MPA, which is biotransformed in the intestine from MPA glucuronide (MPAG) conjugate excreted via the biliary system; however, the molecular mechanism underlying this biotransformation of MPA is still unclear. In this study, an in vitro system was established to evaluate ß-glucuronidase-mediated deconjugation and to examine the influence of ciprofloxacin on the enzymatic deconjugation of MPAG and MPA resynthesis. Resynthesis of MPA via deconjugation of MPAG increased in a time-dependent manner from 5 to 60 min in the presence of ß-glucuronidase. Ciprofloxacin and phenolphthalein-ß-d-glucuronide (PhePG), a typical ß-glucuronidase substrate, significantly decreased the production of MPA from MPAG in the ß-glucuronidase-mediated deconjugation system. In addition, enoxacin significantly inhibited the production of MPA from MPAG, while levofloxacin and ofloxacin had no inhibitory effect on MPA synthesis. Pharmacokinetic analysis revealed that ciprofloxacin showed a dose-dependent inhibitory effect on MPA production from MPAG via ß-glucuronidase with a half-maximal inhibitory concentration (IC50 ) value of 30.4 µm. While PhePG inhibited the ß-glucuronidase-mediated production of MPA from MPAG in a competitive manner, ciprofloxacin inhibited MPA synthesis via noncompetitive inhibition. These findings suggest that the reduction in the serum MPA concentration during the co-administration of ciprofloxacin is at least in part due to the decreased enterohepatic circulation of MPA because of noncompetitive inhibition of deconjugation of MPAG by intestinal ß-glucuronidase.

Population analysis of myelosuppression profiles using routine clinical data after the ICE (ifosfamide/carboplatin/etoposide) regimen for malignant gliomas.

We propose a simple and practical modeling approach for analysis of the data for myelosuppression after cancer chemotherapy, which can be applied when pharmacokinetic data are not available and several anticancer drugs were simultaneously administered. The model equation is based on the probability density function for the Erlang distribution. The data for cell counts of leukocytes (white blood cell, WBC), platelets (PLT), and reticulocytes (RET) obtained in routine clinical laboratory tests after the ICE (ifosfamide/carboplatin/etoposide) regimen for cancer chemotherapy were retrospectively collected from 28 patients, and a population analysis was applied. The time course profiles could be well explained by the proposed model. The individual values of the time to reach the nadir were obtained by the Bayesian method, and their medians (days) were 16.8 for WBC, 12.8 for PLT, and 8.2 for RET. Such information would be useful to determine the day of visit for outpatients especially for additional treatment to prevent side effects such as infections. The model is simple and applicable to explain the time course profiles for myelosuppression irrespective of cell types, and also practical because it requires only the data from routine clinical laboratory tests without any additional burden to patients.

[Evaluation of stability of temozolomide in solutions after opening the capsule].

We evaluated the stability of temozolomide, an alkylating agent, in solutions after opening the capsule. First, we established an analytical method for determination of temozolomide concentration by HPLC. The calibration curve for temozolomide was linear between 0.5-20 microg/ml (r=0.999). We then evaluated the stability of temozolomide in each buffer solution (pH 2-9) for 30 min. Temozolomide was decomposed pH-dependently between pH 7 and 9, and completely decomposed at pH 9. Temozolomide in several drinking water samples and beverages was decomposed according to their pH values. We also examined the time-dependent degradation of temozolomide in different pH solutions. Temozolomide started to decompose at 5 min in alkaline and neutral solutions, whereas 90% of temozolomide remained intact in acidic solution at 60 min. These results indicate that the stability of temozolomide after opening the capsule is affected by pH of solvents, and temozolomide is almost stable in acidic solutions.

Protective effect of a protein kinase inhibitor on cellular injury induced by cephaloridine in the porcine kidney cell line LLC-PK(1).

We investigated the effects of a protein kinase C inhibitor and a tyrosine kinase inhibitor on the cellular injury induced by cephaloridine in an established renal epithelial cell line, LLC-PK(1). Cephaloridine increased the leakage of lactate dehydrogenase (LDH) from LLC-PK(1) cells into the medium and also caused an increase in the level of lipid peroxide (index of oxidative stress) in the cells. Treatment of the cells with a hydroxyl radical scavenger, dimethylthiourea (DMTU), inhibited the increases in LDH leakage and lipid peroxidation in LLC-PK(1) cells exposed to cephaloridine. A protein kinase C inhibitor, H-7, and tyrosine kinase inhibitors, genistein and lavendustinA, inhibited the increases in LDH leakage and lipid peroxidation in LLC-PK(1) cells exposed to cephaloridine. These results suggest that a signaling pathway which involves protein kinase C and tyrosine kinase plays a role in the generation of reactive oxygen species in LLC-PK(1) cells damaged by cephaloridine.

Enhanced expression of enterocyte P-glycoprotein depresses cyclosporine bioavailability in a recipient of living donor liver transplantation.

We evaluated levels of intestinal expression of absorptive-barrier P-glycoprotein (PGP) and cytochrome P-450 IIIA4 (CYP3A4) and immunosuppressant therapy in a patient who underwent living donor liver transplantation (LDLT) and received a second living donor liver transplant after chronic rejection of the first. PGP and CYP3A4 expression were measured using part of a Roux-en-Y limb. After the first LDLT, the concentration-dose ratio of orally administered tacrolimus was 159.8 +/- 125.3 (average +/- SD of 32 different days), similar to the average for 46 recipients of living donor liver transplants in our hospital (161.3 +/- 88.1). However, the recipient required very large oral doses of cyclosporine (703.9 +/- 385.4 mg/d, average +/- SD of 13 different days) after the second LDLT. Although intestinal PGP level was increased markedly at the second LDLT, CYP3A4 level was decreased. In addition, levels of messenger RNA expression of several gene products related to the local inflammation, such as cyclooxygenase 2, interleukin-1beta (IL-1beta), IL-2, IL-6, IL-8, IL-10, and tumor necrosis factor-alpha, were increased. These results suggest that hepatic failure after LDLT, including chronic rejection and/or cholangitis, was accompanied by upregulation of intestinal PGP expression, which could depress the bioavailability of the immunosuppressant.

Organic anion transporter oatp2-mediated interaction between digoxin and amiodarone in the rat liver.

PURPOSE: The interaction between amiodarone and digoxin has been known to increase serum concentrations of digoxin in humans and rats. In this study, we assessed the molecular mechanism(s) of that drug interaction, focusing on digoxin transport mediated by P-glycoprotein (Pgp) and by rat liver organic anion transporter (oatp2). METHODS: Digoxin transport by Pgp and oatp2 was assessed using Pgp-overexpressing transfectant LLC-GA5-COL150 monolayers and oatp2-expressing Xenopus oocytes, respectively. The digoxin uptake into the isolated rat hepatocytes was also examined. RESULTS: Amiodarone (10 microM) inhibited slightly the transcellular transport of digoxin in LLC-GA5-COL150 monolayers, whereas itraconazole (10 microM), a potent Pgp inhibitor, markedly blocked the transport. The digoxin uptake by the isolated rat hepatocytes and by the oatp2-expressing Xenopus oocytes was decreased markedly in the presence of amiodarone but not in the presence of itraconazole. In addition, amiodarone inhibited the oatp2-mediated digoxin uptake in a competitive manner with an apparent inhibition constant value of 1.8 microM. CONCLUSION: These findings suggest that rat oatp2 rather than Pgp may be one of the interaction sites for digoxin and amiodarone in the liver.