ABSTRACT
Ochrobactrum anthropi, a rare human pathogen, has been isolated predominantly from patients with catheter-related bacteraemia and rarely from other infections. In 2016, six cases of pseudo-bacteraemia caused by carbapenem-resistant O. anthropi isolates were recovered from an Argentinian hospital. The resistant phenotype exposed by the isolates caught our attention and led to an extensive epidemiologic investigation. Here we describe the characterization of a carbapenem-resistant O. anthropi outbreak whose probable cause was by contaminated collection tubes. The genome analysis of one strain revealed the presence of various resistant determinants. Among them, a metal-dependent hydrolase of the ß-lactamase superfamily I, phnP, was found. Lately the recovery of unusual multidrug-resistant pathogens in the clinical setting has increased, thus emphasizing the need to implement standardized infection control practice and epidemiologic investigation to identify the real cause of hospital outbreaks.
Subject(s)
Dermatitis/genetics , Desmoglein 1/genetics , Hypersensitivity/genetics , Mutation/genetics , Wasting Syndrome/genetics , Adult , Age of Onset , Child , Desmoglein 1/deficiency , Exome , Genes, Recessive , Genome-Wide Association Study , Humans , Keratoderma, Palmoplantar/genetics , Norway , Pedigree , SyndromeABSTRACT
Holins are small membrane proteins that, at a genetically programmed time in a bacteriophage infective cycle, allow bacteriolytic enzymes, or endolysins, to escape to the periplasm and to attack the cell wall. Most holins fall into two sequence classes, I and II, based on the number of potential transmembrane domains (three for class I and two for class II). The prototype class I holin gene, S lambda, has a dual start motif and encodes not only the effector holin, Slambda105, but also an inhibitor, Slambda107, with a Met-Lys ...extension at the terminus. The prototype class II holin gene of phage 21, S 21, begins with the motif Met-Lys-Ser-Met ..., and a potential RNA secondary structure overlaps the Shine-Dalgarno sequence. Here, we demonstrate that (i) two protein products are elaborated from S 21, S2171 and S2168; (ii) the shorter product is required for lysis; (iii) the longer product, S2171, inhibits S 21 function; and (iv) the Lys-2 residue is important for the inhibitor function. Moreover, the RNA stem-loop structure is involved in the downregulation of S2171 synthesis. However, our results suggest that, in S 21, different segments of the single consensus Shine-Dalgarno sequence serve the two translational starts. These results show that the dual start motifs of class II holin genes are functionally homologous to those of class I holin genes.
Subject(s)
Bacteriophage lambda/genetics , Genes, Viral , Viral Proteins/genetics , Alleles , Amino Acid Sequence , Base Sequence , DNA-Directed RNA Polymerases/metabolism , Lysogeny/genetics , Membrane Proteins/chemistry , Membrane Proteins/genetics , Molecular Sequence Data , Mutation , Nucleic Acid Conformation , Plasmids , Protein Biosynthesis , RNA, Messenger/genetics , Transcriptional Activation , Viral Proteins/chemistryABSTRACT
The gene encoding thioredoxin (trxA) was isolated from chromosomal DNA of E. coli HB101 strain using the polymerase chain reaction. The cloned structural gene with a synthetic Shine-Dalgarno sequence was placed under the control of either inducible tac-promoter or a tandem of two strong constitutive promoters A2 and A3 from early region of bacteriophage T7. Both constructions were shown to provide high levels of biosynthesis of recombinant thioredoxin.
