Genomic structure, organization and localization of the acetylcholinesterase locus of the olive fruit fly, Bactrocera oleae.

Acetylcholinesterase (AChE), encoded by the ace gene, is a key enzyme of cholinergic neurotransmission. Insensitive acetylcholinesterase (AChE) has been shown to be responsible for resistance to OPs and CBs in a number of arthropod species, including the most important pest of olives trees, the olive fruit fly Bactrocera oleae. In this paper, the organization of the B. oleae ace locus, as well as the structural and functional features of the enzyme, are determined. The organization of the gene was deduced by comparison to the ace cDNA sequence of B. oleae and the organization of the locus in Drosophila melanogaster. A similar structure between insect ace gene has been found, with conserved exon-intron positions and junction sequences. The B. oleae ace locus extends for at least 75 kb, consists of ten exons with nine introns and is mapped to division 34 of the chromosome arm IIL. Moreover, according to bioinformatic analysis, the Bo AChE exhibits all the common features of the insect AChE. Such structural and functional similarity among closely related AChE enzymes may implicate similarities in insecticide resistance mechanisms.

Group B Streptococcus (Streptococcus agalactiae) peritonitis associated with continuous ambulatory peritoneal dialysis (CAPD).

Streptococcus agalactiae typically induces serious infections in pregnant women and newborns. Nonpregnant adult patients can also be infected and mortality rate exceeds 40%. CAPD peritonitis is very rarely induced by S. agalactiae. Seven cases have been described previously and all had a very severe course, which included bacteremia, septic shock and death. A 27-year-old male with end-stage renal disease due to membranoprolipherative glomerulonephritis type I, who was on CAPD for 17 months, was admitted with the clinical and laboratory picture of CAPD peritonitis. Severe abdominal pain, shaking chills and fever 38.5 microC were also observed at presentation. Streptococcus agalactiae was isolated from the peritoneal fluid and blood culture was sterile. Under treatment with ceftazidime and tobramycin (i.p.) and vancomycin (i.v.) cultures became negative after 48 hours, abdominal symptoms resolved after 12 days and WBC count in the dialysate normalized after 14 days. As a possible source of infection the patient's partner was shown to be a vaginal carrier of a clone of S. agalactiae identical to that isolated in the peritoneal fluid. S. agalactiae is a rare cause of CAPD peritonitis with potentially very serious consequences. Anal or genital tract colonization is, in general, the source of contamination with S. agalactiae. The microbiological findings in the case presented here suggest that colonization of the patient or of his close environment may be important in the pathogenesis of S. agalactiae-induced CAPD peritonitis.

The emergence of glycopeptide-resistant Enterococcus faecium in a university hospital in southwestern Greece.

BACKGROUND: Enterococci and especially glycopeptide-resistant strains (GRE) are widely distributed in the hospital environment, by acquiring resistance determinants and virulence factors. METHODS: The study included 48 GRE isolated during a 1-year period from different inpatients in a tertiary hospital in southwestern Greece. Antibiotic susceptibility was determined by the Etest, and the presence of resistance and virulence genes was shown by PCR. Clonal types were identified by pulsed-field gel electrophoresis of SmaI DNA digests. RESULTS: All GRE were multi-resistant of the VanA phenotype, verified by the detection of the gene by PCR. Two major clones were distributed in all hospital wards. The majority of the strains (46 of 48) harbored the esp gene, while 27 GRE expressed also the gelE and/or as genes. CONCLUSIONS: The spread of two clones expressing the vanA gene and virulence factors were responsible for the emergence of GRE in the University Hospital of Patras.