54 research outputs found
Streptococcus suis, an Emerging Drug-Resistant Animal and Human Pathogen
Streptococcus suis, a major porcine pathogen, has been receiving growing attention not only for its role in severe and increasingly reported infections in humans, but also for its involvement in drug resistance. Recent studies and the analysis of sequenced genomes have been providing important insights into the S. suis resistome, and have resulted in the identification of resistance determinants for tetracyclines, macrolides, aminoglycosides, chloramphenicol, antifolate drugs, streptothricin, and cadmium salts. Resistance gene-carrying genetic elements described so far include integrative and conjugative elements, transposons, genomic islands, phages, and chimeric elements. Some of these elements are similar to those reported in major streptococcal pathogens such as Streptococcus pyogenes, Streptococcus pneumoniae, and Streptococcus agalactiae and share the same chromosomal insertion sites. The available information strongly suggests that S. suis is an important antibiotic resistance reservoir that can contribute to the spread of resistance genes to the above-mentioned streptococci. S. suis is thus a paradigmatic example of possible intersections between animal and human resistomes
Streptococcus suis Meningitis without History of Animal Contact, Italy
Streptococcus suis, a major swine pathogen worldwide, is emerging as a zoonotic agent capable of causing a variety of serious infections in swine as well as in persons exposed to pigs or to pork products. These infections include meningitis, septicemia, pneumonia, endocarditis, arthritis, and septic shock (1,2). Despite recent outbreaks among persons in China, S. suis disease in humans is a rare, probably underdiagnosed infection that usually occurs as sporadic cases (1,2). Persons in close occupational or accidental contact with pigs or pork products and those who eat uncooked or undercooked pork may be at higher risk than others. However, most infected persons are likely healthy carriers, and S. suis is believed to induce overt disease (especially meningitis) in only some circumstances (2). We describe a case of S. suis meningitis in a 68-year-old man from Sardinia, Italy, who had no reported contact with swine, other animals, or any animal products; the patient also had cancer, which was discovered incidentally during the workup
Streptococcus suis Meningitis without History of Animal Contact, Italy
Streptococcus suis, a major swine pathogen worldwide, is emerging as a zoonotic agent capable of causing a variety of serious infections in swine as well as in persons exposed to pigs or to pork products. These infections include meningitis, septicemia, pneumonia, endocarditis, arthritis, and septic shock (1,2). Despite recent outbreaks among persons in China, S. suis disease in humans is a rare, probably underdiagnosed infection that usually occurs as sporadic cases (1,2). Persons in close occupational or accidental contact with pigs or pork products and those who eat uncooked or undercooked pork may be at higher risk than others. However, most infected persons are likely healthy carriers, and S. suis is believed to induce overt disease (especially meningitis) in only some circumstances (2). We describe a case of S. suis meningitis in a 68-year-old man from Sardinia, Italy, who had no reported contact with swine, other animals, or any animal products; the patient also had cancer, which was discovered incidentally during the workup
Characterization of a Multiresistance Plasmid Carrying the optrA and cfr Resistance Genes From an Enterococcus faecium Clinical Isolate
open13noEnterococcus faecium E35048, a bloodstream isolate from Italy, was the first strain where the oxazolidinone resistance gene optrA was detected outside China. The strain was also positive for the oxazolidinone resistance gene cfr. WGS analysis revealed that the two genes were linked (23.1 kb apart), being co-carried by a 41,816-bp plasmid that was named pE35048-oc. This plasmid also carried the macrolide resistance gene erm(B) and a backbone related to that of the well-known Enterococcus faecalis plasmid pRE25 (identity 96%, coverage 65%). The optrA gene context was original, optrA being part of a composite transposon, named Tn6628, which was integrated into the gene encoding for the ζ toxin protein (orf19 of pRE25). The cfr gene was flanked by two ISEnfa5 insertion sequences and the element was inserted into an lnu(E) gene. Both optrA and cfr contexts were excisable. pE35048-oc could not be transferred to enterococcal recipients by conjugation or transformation. A plasmid-cured derivative of E. faecium E35048 was obtained following growth at 42°C, and the complete loss of pE35048-oc was confirmed by WGS. pE35048-oc exhibited some similarity but also notable differences from pEF12-0805, a recently described enterococcal plasmid from human E. faecium also co-carrying optrA and cfr; conversely it was completely unrelated to other optrA- and cfr-carrying plasmids from Staphylococcus sciuri. The optrA-cfr linkage is a matter of concern since it could herald the possibility of a co-spread of the two genes, both involved in resistance to last resort agents such as the oxazolidinones.openMorroni, Gianluca; Brenciani, Andrea; Antonelli, Alberto; Maria D’Andrea, Marco; Di Pilato, Vincenzo; Fioriti, Simona; Mingoia, Marina; Vignaroli, Carla; Cirioni, Oscar; Biavasco, Francesca; Varaldo, Pietro E.; Rossolini, Gian Maria; Giovanetti, EleonoraMorroni, Gianluca; Brenciani, Andrea; Antonelli, Alberto; Maria D’Andrea, Marco; Di Pilato, Vincenzo; Fioriti, Simona; Mingoia, Marina; Vignaroli, Carla; Cirioni, Oscar; Biavasco, Francesca; Varaldo, Pietro E.; Rossolini, Gian Maria; Giovanetti, Eleonor
L’emergenza della resistenza batterica agli antibiotici e il suo impatto sul laboratorio di microbiologia clinica*
Le riflessioni qui riportate sono state elaborate, in parte, in occasione di riunioni dell’AMCLI Marche (Jesi, 19.10.2001) e del Comitato AMCLI per lo Studio degli Antibiotici (CoSA) (Milano, 11.12.2001 e Firenze, 11.4.2002) e, in parte, in un Leading Article su Journal of Antimicrobial Chemotherapy (Varaldo PE.Antimicrobial resistance and susceptibility testing: an evergreen topic. J.Antimicrob. Chemother. 2002; 50: 1-4)
Interactions between Glycopeptides and β-Lactams against Isogenic Pairs of Teicoplanin-Susceptible and -Resistant Strains of Staphylococcus haemolyticus
Four isogenic derivatives with stably increased glycopeptide MICs (all become resistant to teicoplanin) were obtained from four glycopeptide-susceptible clinical isolates of Staphylococcus haemolyticus. All strains were extensively analyzed and compared for a number of distinctive features. In particular, the results provided insights into the puzzling issue of antistaphylococcal interactions between glycopeptides and β-lactams, especially the paradox of double zones around β-lactam disks and the relationships between autolysis rate and type of interaction
Composite SCCmec Element in Single-locus Variant (ST217) of Epidemic MRSA-15 Clone
Composite SCCmec element in single-locus variant (ST217) of epidemic MRSA-15 clon
Genetic Elements Responsible for Erythromycin Resistance in Streptococci▿
Until a decade ago, knowledge about the genetic elements
responsible for erythromycin resistance in streptococci was virtually
confined to a few plasmids or transposons carrying erm(B),
then called ermAM or simply erm (56, 65). Such transposons
mainly included Tn917, detected in Enterococcus faecalis when it
was still regarded as a Streptococcus species (94, 101, 102), and
Tn1545, detected in S. pneumoniae and also encoding resistance,
besides tetracycline, to erythromycin and kanamycin (31, 32).
Remarkably, Tn1545 was related to Tn916 (47), the prototype of
a family of broad-host-range conjugative transposons conferring
tetracycline resistance via the tet(M) gene (24, 81). Other Tn916-
related erm(B)-carrying transposons early described in Streptococcus
species (81) ceased to be reported in later studies. During the
last decade, the discovery of the above-mentioned variety of
erythromycin resistance genes in streptococci has been closely
followed by the identification and characterization of a variety of
genetic elements responsible for the resistance and its possible
spread via intra- and interspecific transfer. Different erythromycin
resistance genes are carried by different elements: in the case of
mef genes, such close gene-element association was a major argument
for recommending that mef(A), mef(E), and any future
mef variants continue to be discriminated and kept apart (60) as
opposed to being collected in a single class, mef(A), due to their
high degree of similarity (84). This minireview is aimed at presenting
such new knowledge about the genetic elements responsible
for erythromycin resistance in streptococci
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