title: Prevalence, phenotypic and genetic characteristics of prolyliminopeptidase-negative Neisseria gonorrhoeae isolates in Sweden during 2000-2007.
abstract: In Neisseria gonorrhoeae culture diagnostics, species confirmation is commonly performed using commercial biochemical tests relying on prolyliminopeptidase (PIP) activity. It was previously shown that one PIP-negative strain was mainly globally transmitted during 2000-2004. The aims were to investigate the prevalence and phenotypic and genetic characteristics of PIP-negative N. gonorrhoeae isolates in Sweden during 2000-2007. Gonococcal isolates (n = 1230) cultured in Sweden during 2000-2007 were characterized using PIP screening, antibiogram, serovar determination, pip and porB gene sequencing, and N. gonorrhoeae multiantigen sequence typing (NG-MAST). Fifteen (1.2%) of the isolates were PIP-negative. Of those, 13 (87%) were indistinguishable to the previously described globally transmitted strain, i.e. displayed serovar IB-4 (Bpyvut), similar antibiograms, ST210 (n = 10)/ST292 (n = 3) and contained an identical single nucleotide pip gene deletion. Wherever high reliance is placed on PIP activity for N. gonorrhoeae species confirmation, changes in the diagnostic strategies may need to be considered and/or monitoring of the PIP activity is crucial.
authors.affiliation: National Reference Laboratory for Pathogenic Neisseria, Department of Laboratory Medicine, Clinical Microbiology, Orebro University Hospital, Orebro, Sweden.
authors.forename: Emma
authors.initials: E
authors.lastname: Johansson
authors.forename: Hans
authors.initials: H
authors.lastname: Fredlund
authors.forename: Magnus
authors.initials: M
authors.lastname: Unemo
mesh_terms: D000483:Alleles; D000626:Aminopeptidases / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D017353:Gene Deletion; D006069:Gonorrhea / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D016254:Mutagenesis, Insertional; D009344:Neisseria gonorrhoeae / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*; D015995:Prevalence; D013548:Sweden / Q000453:epidemiology
chemical_list: D001426:Bacterial Proteins; D000626:Aminopeptidases; C022450:prolyl aminopeptidase