117,449 research outputs found
Activities of 16-membered ring macrolides and telithromycin against different genotypes of erythromycin-susceptible and erythromycin-resistant Streptococcus pyogenes and Streptococcus pneumoniae.
No full textOBJECTIVES:
To test four 16-membered macrolides (josamycin, spiramycin, midecamycin and rokitamycin) along with other compounds in the same class (erythromycin, clarithromycin, roxithromycin and azithromycin) plus clindamycin and telithromycin, against Streptococcus pyogenes and Streptococcus pneumoniae isolates with well-characterized resistance genotypes.
METHODS:
Four hundred and eighty-six isolates of S. pyogenes and 375 isolates of S. pneumoniae were assayed for their macrolide susceptibilities and investigated by PCR to detect their different erythromycin resistance genes. All strains had been isolated over the period 2002-2003 from specimens of different human origin obtained in 14 different Italian centres.
RESULTS:
All 16-membered macrolides showed very low MICs (MIC(50)s and MIC(90)s, or = 256 mg/L, whereas that for telithromycin was 4 mg/L; the MIC(50)s of 16-membered macrolides and telithromycin ranged from or = 256 mg/L for those with erm(B). In S. pneumoniae, the MIC(50)s of the 16-membered macrolides for the cMLS(B) isolates ranged from 0.5 to 128 mg/L, whereas for the iMLS(B) isolates their values ranged from < or = 0.06 to 4 mg/L; the MIC(50)s and MIC(90)s of telithromycin for both the cMLS(B) and the iMLS(B) isolates ranged from < or = 0.06 to 0.12 mg/L.
CONCLUSIONS:
MICs ranged for all the drugs, except telithromycin, from or = 256 mg/L, with 15% to 30% resistant S. pyogenes for all drugs tested except clindamycin (8%) and telithromycin (5.4%) and 10% to 40% resistant S. pneumoniae for all drugs tested except telithromycin (0.3%). In both S. pyogenes and S. pneumoniae, erythromycin resistance related to a mef gene meant that telithromycin MICs were definitely higher than in erythromycin-susceptible isolates, although telithromycin susceptibility was preserved in all cases. In S. pyogenes, the activity of both 16-membered macrolides and telithromycin against the iMLS(B) strains proved to be dependent on the erm gene involved, being greater against isolates with erm(A)
Molecular signatures in cetacean morbillivirus and host species proteomes: Unveiling the evolutionary dynamics of an enigmatic pathogen?
No full textCetacean morbillivirus (CeMV) infects marine mammals often causing a fatal respiratory and neurological disease. Recently, CeMV has expanded its geographic and host species range, with cases being reported worldwide among dolphins, whales, seals, and other aquatic mammalian species, and therefore has emerged as the most threatening nonanthropogenic factor affecting marine mammal's health and conservation. Extensive research efforts have aimed to understand CeMV epidemiology and ecology, however, the molecular mechanisms underlying its transmission and pathogenesis are still poorly understood. In particular, the field suffers from a knowledge gap on the structural and functional properties of CeMV proteins and their host interactors. Nevertheless, the body of scientific literature produced in recent years has inaugurated new investigational trends, driving future directions in CeMV molecular research. In this mini-review, the most recent literature has been summarized in the context of such research trends, and categorized into four priority research topics, such as (1) the interaction between CeMV glycoprotein and its host cell receptors across several species; (2) the CeMV molecular determinants responsible for different disease phenotype; (3) the host molecular determinants responsible for differential susceptibility to CeMV infection; (4) the CeMV molecular determinants responsible for difference virulence among circulating CeMV strains. Arguably, these are the most urgent topics that need to be investigated and that most promisingly will help to shed light on the details of CeMV evolutionary dynamics in the immediate future
Cetacean mass strandings and multidisciplinary work
No full textLetter to the Editor discussing the paper Squadrone, S., Chiaravalle, E., Gavinelli, S., Monaco, G., Rizzi, M., Abete, M.C., 2015. Analysis of mercury and methylmercury concentrations, and selenium:mercury molar ratios for a toxicological assessment of sperm whales (Physeter macro- cephalus) in the most recent stranding event along the Adriatic coast (Southern Italy, Mediterranean Sea). Chemosphere 138, 633e64
Renal dysplasia in grey Alpine breed cattle unrelated to CLDN16 mutations
No full textRENAL dysplasia (RD) is a developmental disorder of the renal parenchyma characterised by anomalous differentiation of the nephrons and collecting ducts (Woolf and others 2004). In human medicine, RD is one of the principal causes of childhood end-stage renal failure. In veterinary medicine, it has been described in several species, including cattle (Dunham and others 1989, Simon and others 1999, Ohba and others 2001, Castro and others 2007, Maxie and Newman 2007, Aresu and others 2009, Philbey and others 2009). In Japanese Black cattle, RD shows autosomal recessive inheritance, caused by CLDN16 mutations (Hirano and others 2000, Ohba and others 2000, Hirano and others 2002). These mutations affect one of the members of the claudin family of genes which plays an important role in the formation of tight junctions in the kidney (Simon and others 1999). In Japanese Black cattle, RD is classified into two types, according to two independent CLDN16 mutations (Hirano and others 2002), but no morphological or histopathological differences between the two types have been reported. This short communication deals with a case of RD in twin grey Alpine heifers which are not related to mutations of the CLDN16 gene
Myiasis by Megaselia scalaris (Diptera: Phoridae) in a Python Affected by Pulmonitis
No full textMyiases are caused by the presence of maggots in vertebrate tissues and organs. Myiases have been studied widely in humans, farm animals, and pets, whereas reports of myiasis in reptiles are scarce. We describe a case of myiasis caused by the Megaselia scalaris (Loew) in an Indian python (Python molurus bivittatus, Kuhl) (Ophida: Boidae). The python, 15 yr old, born and reared in a terrarium in the mainland of Venice (Italy), was affected by diffuse, purulent pneumonia caused by Burkholderia cepacia. The severe infestation of maggots found in the lungs during an autopsy indicated at a myiasis
Outbreak of linezolid-resistant Staphylococcus haemolyticus in an Italian intensive care unit
No full textWe report an outbreak of linezolid-resistant Staphylococcus haemolyticus strains (MIC 32 mg/L) in patients admitted to the Verona University Hospital Intensive Care Unit. The strains proved to be clonally related at pulsed field gel electrophoresis. All the strains showed the G2576T mutation responsible for linezolid-resistance and retained their resistance even after several passages on antibiotic-free medium. After a decade of linezolid use, multifocal emergence of linezolid resistance in coagulase-negative staphylococci has become an important matter of concern and mandates stricter control over the use of this antibiotic in order to preserve its clinical utility
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Co-infection by two linezolid-resistant coagulase-negative staphylococci with two different resistance determinants.
No full textLinezolid resistance among Gram-positive pathogens is being reported with increasing frequency. We examined 14 linezolid-resistant coagulase-negative staphylococci (CoNS) isolated from blood cultures obtained from patients admitted to the Intensive Care Unit of Vicenza General Hospital, Italy. The species identification yielded 10 Staphylococcus epidermidis, 3 Staphylococcus hominis, and 1 Staphylococcus capitis. Minimal inhibitory concentrations of linezolid ranged between 16 and 32 mg/l. By sequencing domain V of the 23S rRNA gene, 4 isolates were found to harbour a G2576T mutation and 10 isolates a G2447T mutation. None of the strains under study presented either the cfr gene or cardinal mutations in the L3, L4, or L22 riboproteins. In this clinical collection of linezolid-resistant CoNS the G2447T mutation was dominantly associated with S. epidermidis, while the G2576T mutation was found in other CoNS species. Two different CoNS species endowed with either mutation were isolated from 2 patients
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