Detection of colonization by carbapenem-resistant organisms by real-time polymerase chain reaction from rectal swabs in patients with chronic renal disease.

BACKGROUND: Carbapenem-resistant organism (CRO) colonization is a serious problem that increases the risk of infection and contributes to dissemination of antimicrobial resistance in healthcare-associated environments. The risk of acquisition and dissemination of CRO is high in chronic renal failure patients and the surveillance culture is recommended as a component of infection control programmes. AIM: To assess colonization by CRO, comparing phenotypic and molecular-based methods of diagnostics, in rectal swabs in a large population of chronic renal failure patients. METHODS: A total of 1092 rectal swabs (ESwab™) were collected at two different times from 546 chronic kidney disease (CKD) patients from a specialized tertiary care university centre. They were divided into three groups: conservative treatment (N = 129), dialysis (N = 217), and transplanted patients (N = 200). A chromogenic (CHROMagar™) KPC agar and the multiplex real-time polymerase chain reaction (qPCR) targeting carbapenemase-encoding genes were tested as phenotypic and molecular screening for carbapenemase production. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and conventional PCR were also performed on the isolates grown on chromogenic agar. FINDINGS: Among the 1092 samples, 150 (13.7%) were identified as CRO producers according to chromogenic agar. Only 26 (2.4%) were confirmed as KPC by conventional PCR. According to qPCR direct from swab, 31 (2.8%) were positive for KPC, 39 (3.6%) for GES, and three (0.3%) for SPM with kappa index of 0.256. CONCLUSION: The qPCR technique provides faster results when compared to culture method and enables rapid implementation of control measures and interventions to reduce the spread of CRO in healthcare settings, especially among CKD patients.

Gordonia terrae kidney graft abscess in a renal transplant patient.

We present the first report, to our knowledge, of a renal abscess cause by an infection from Gordonia terrae in a kidney transplant patient. The patient simultaneously had pulmonary tuberculosis and a perirenal allograft abscess caused by G. terrae. After treatment with imipenem, in addition to anti-tuberculous drugs, the patient was cured.

P-glycoprotein in the catfish intestine: inducibility by xenobiotics and functional properties.

The p-glycoprotein (pgp)-mediated multixenobiotic resistance (MXR) mechanism of aquatic animals has been associated with protection against pollution. Recent studies in mammals suggest that intestinal pgp may modulate intestinal bioavailability of dietary xenobiotics. In order to further delineate this mechanism in the catfish, these studies: (1) examined the pgp-related distribution in the intestine and liver of catfish, (2) evaluated the MXR response following exposure to various dietary xenobiotics and a prototypic pgp inducer and (3) evaluated pgp functional activity in membrane vesicles, using prototypic substrates and inhibitors. For this purpose, catfish were exposed in vivo to the pgp inducer vincristine (VIN), and the xenobiotics beta-naphthoflavone (BNF), benzo[a]pyrene (BaP), and 3,4,3',4'-tetrachlorobiphenyl (TCB). Membrane vesicles, prepared from liver and intestine (proximal and distal sections) of control and exposed catfish, were subjected to SDS PAGE, Western Blot, and detection with the pgp C219 monoclonal antibody. Transport activity was evaluated in vitro using the pgp substrate [3H]vinblastine (VBL), and the pgp inhibitor verapamil (VP). Immunoblot studies demonstrated a pgp-related protein of approximately 170 kDa in the intestine and liver of catfish. This protein appears to be very susceptible to degradation, and was present in higher levels in the liver, in comparison to the intestine, where regional differences were not observed. Dietary exposure to the pgp substrate VIN, or the xenobiotics BNF, BaP, and TCB, did not appear to affect pgp-related reactivity. Transport studies with VBL indicate that the pgp-related protein of the catfish intestine displays classic pgp-mediated multidrug resistance (MDR) characteristics, such as energy-dependency, and sensitivity to VP. These studies suggest that the pgp-related protein in the catfish intestine and liver is not only immunochemically, but also functionally related to the mammalian MDR. Moreover, the results presented indicate that pgp-related reactivity and transport in intestinal vesicles of catfish may be influenced by factors including method sensitivity, sample collection, sample preparation, and immunoblot conditions.

Effect of micelle fatty acid composition and 3,4,3', 4'-tetrachlorobiphenyl (TCB) exposure on intestinal [(14)C]-TCB bioavailability and biotransformation in channel catfish in situ preparations.

Polychlorinated biphenyls are transferred in the diet along aquatic food chains. This study investigated the effect of dietary micelle composition and 3,4,3',4'-tetrachlorobiphenyl (TCB) exposure upon the subsequent systemic bioavailability and intestinal metabolism of [(14)C]-TCB in a catfish in situ intestinal preparation. Initial in vitro experiments examined the solubility of [(14)C]-TCB in micelles of varying fatty acid composition. Micelles composed of single fatty acids demonstrated greater [(14)C]-TCB solubility with those fatty acids of longer chain length. Similarly, micelles of the long-chain fatty acid, linoleic acid, solubilized more [(14)C]-TCB than mixed micelles formulated from equal amounts of myristic (14:0), palmitic (16:0), stearic (18:0), or linoleic (18:2) acids. Systemic bioavailability of [(14)C]-TCB (60 microM) from an in situ perfused intestinal preparation was 2.2-fold greater when delivered to the intestine in linoleic acid micelles as compared to the mixed micelle preparation. Catfish exposed in vivo to either 0.5 or 5.0 mg TCB/kg feed for 10 days resulted in a 45 to 47% decrease in the subsequent systemic bioavailability of [(14)C]-TCB in the in situ intestinal preparation. Total intestinal cytochrome P450 content was not significantly affected by TCB preexposure. Immunodetectable CYP1A was found only in the 5.0 mg TCB/kg diet treatment. Corresponding intestinal aryl hydrocarbon hydroxylase (AHH) activities were 2.46 +/- 1.16, 2.43 +/- 1.58, and 11.35 +/- 10.25 pmol/min/mg protein for the control, 0.5, and 5 mg TCB/kg diet groups, respectively. [(14)C]-TCB in the in situ preparation was metabolized to only a small degree upon a single pass through the intestinal mucosa of the catfish. High variability and low rates of metabolism precluded the association of the magnitude of metabolism with dietary TCB pretreatment. Analysis of tissue sample extracts demonstrated 4 minor peaks, 3 of which were tentatively identified by co-elution with standards as 2-OH-3,4,3',4'-TCB, 4-OH-3,5,3',4'-TCB, and 5-OH-3, 4,3',4'-TCB. A fourth remains unidentified. Histological changes in the intestine such as thinning of the submucosa and increased numbers of goblet cells were evident at the 5.0 mg TCB/kg diet dose. These results suggest that TCB intestinal bioavailability may be linked to micelle composition as well as TCB exposure history. Furthermore, single pass intestinal metabolism appears to be a minor contributor to the biotransformational modification of dietary TCB.

Distribution and inducibility of P-glycoprotein in the catfish: immunohistochemical detection using the mammalian C-219 monoclonal.

Mounting evidence suggests that the P-glycoprotein (pgp) efflux pump may be a modulator of bioavailability and a mode of excretion for xenobiotics. Immunohistochemistry was utilized to examine the distribution and inducibility of a pgp like protein in catfish. Immunoreactivity to the MDR C-219 monoclonal antibody was noted primarily in bile canaliculi or bile preductules of the liver, discrete areas of the extratubular region of the kidney and the columnar epithelia of the intestine. Regional differences in pgp content were noted in the intestine with the distal region containing greater pgp levels than the proximal intestine. Dietary administration of vincristine, a prototypic pgp inducer and beta-naphthoflavone an Ah agonist resulted in induction of the C-219 immunoreactivity in the liver and the distal intestine. These results are consistent in location and inducibility with pgp like proteins and support a possible relationship to xenobiotic absorption and/or excretion in the catfish.

Pharmacokinetics of oxytetracycline in the red pacu (Colossoma brachypomum) following different routes of administration.

Oxytetracycline (OTC) pharmacokinetics were studied in the red pacu (Colossoma brachypomum) following intravenous (i.v.) and intramuscular (i.m.) administration at a dose of 5 mg/kg body weight. OTC plasma concentrations were determined by high-performance-liquid-chromatography (HPLC). A non-compartmental model was used to describe plasma drug disposition after OTC administration. Following i.m. administration, the elimination half-life (t1/2) was 62.65 +/- 1.25 h and the bioavailability was 49.80 +/- 0.01%. After i.v. administration the t1/2 was 50.97 +/- 2.99 h, the Vd was 534.11 +/- 38.58 mL/kg, and CI(b) was 0.121 +/- 0.003 mL/min x kg. The 5 mg/kg i.v. dose used in this experiment resulted in up to 48 h plasma concentrations of OTC above the reported MIC values for some strains of fish pathogens such as Aeromonas hydrophila, A. liquefaciens, A. salmonicida, Cytophaga columnaris, Edwardsiella ictaluri, Vibrio anguillarium, V. ordalii, V. salmonicida and Yeersinia ruckeri. These MIC values are below the susceptible range (4 microg/mL) listed by the National Committee for Clinical Laboratory Standards (NCCLS) as determined by the NCCLS susceptibility interpretive criteria.