UTILITY OF RIBOTYPING, RESTRICTION-ENDONUCLEASE ANALYSIS AND PULSED-FIELD GEL-ELECTROPHORESIS TO DISCRIMINATE BETWEEN ISOLATES OF NEISSERIA-GONORRHOEAE OF SEROVAR IA-2 WHICH REQUIRE ARGININE, HYPOXANTHINE OR URACIL FOR GROWTH
H. Li et Jar. Dillon, UTILITY OF RIBOTYPING, RESTRICTION-ENDONUCLEASE ANALYSIS AND PULSED-FIELD GEL-ELECTROPHORESIS TO DISCRIMINATE BETWEEN ISOLATES OF NEISSERIA-GONORRHOEAE OF SEROVAR IA-2 WHICH REQUIRE ARGININE, HYPOXANTHINE OR URACIL FOR GROWTH, Journal of Medical Microbiology, 43(3), 1995, pp. 208-215
Neisseria gonorrhoeae isolates that require arginine-i.e., either citr
ulline (C), or ornithine (O)-uracil (U) and hypoxanthine (H) have gene
rally been considered to be similar when characterised by auxotype, se
rovar and plasmid content. The MICs of penicillin, tetracycline, eryth
romycin, spectinomycin, cefoxitin and ceftriaxone for 552 isolates bel
onging to serovar IA-2 with these phenotypes were found to be similar.
Therefore, restriction fragment length polymorphism analysis of rRNA
genes (ribotyping), restriction enzyme (RE) analysis of chromosomal DN
A, and pulsed-field gel electrophoresis (PFGE) were evaluated to deter
mine whether these isolates could be distinguished by molecular method
s. A subset of 27 isolates of N. gonorrhoeae that were OUH-requiring,
CUH-requiring or OH-requiring, belonged to serovar IA-2 and carried a
2.6-MDa plasmid, were selected for further study. Based on the RE anal
ysis of SmaI-digested genomic DNA, the 27 isolates fell into a single
RE pattern, five ribotypes and 17 PFGE profiles which did not correlat
e with the specific arginine-requiring subtypes of these isolates. Eac
h ribotype varied by the presence of only a single fragment, which was
of a different size in each,pattern, and 17 (63 %) of the 27 isolates
belonged to ribotype I. PFGE yielded the highest level of discriminat
ion with 17 different profiles.