Novel plasmid combinations in Haemophilus ducreyi isolates from Thailand

Abstract

Thirty isolates of Haemophilus ducreyi collected in Thailand in 1984 were characterized by plasmid content. Three novel plasmids with estimated molecular masses of 1.8, 2.6, and 2.8 MDa were observed in 29 isolates, in addition to the 3.2-, 5.7-, and 7.0-MDa beta-lactamase and 4.4-MDa sulfonamide resistance plasmids. At least three of the seven plasmids were observed in each of the 29 isolates. The number and diversity of plasmids observed in these isolates of H. ducreyi distinguish them from strains previously described.

Chancroid and Haemophilus ducreyi: an update.

“…The HindIII-2 strains could be further differentiated on the basis of their plasmid profile; the strains isolated from the three patients who reported travel to Los Angeles contained a 5.7-MDa plasmid, whereas the strain isolated from the patient who traveled to Korea contained 1.9-, 2.6-, 2.9-, and 3.2-MDa plasmids. This plasmid pattern is similar to that observed in strains isolated in the Far East (136). Four ribotypes appeared to be acquired locally.…”

“…Geographical and temporal differences in antimicrobial susceptibilities have been observed. Many of the differences are due to the presence or absence of resistance plasmids (10,100,136,137). Plasmids which encode resistance, either separately or in combination, to sulfonamides (6,169), aminoglycosides (135,169), tetracyclines (8,92,(126)(127)(128), chloramphenicol (128), and ␤-lactam antibiotics (25,89,90,124,154) have been identified in H. ducreyi (Table 5).…”

“…These plasmids have been reviewed in detail elsewhere (98). It is not unusual for a single H. ducreyi isolate to contain multiple resistance plasmids (45,136,137), including more than one plasmid that confers resistance to ␤-lactam antibiotics. Strains containing both a 7.0-MDa TEM-1 ␤-lactamase plasmid and a 3.5-MDa ROB-1 ␤-lactamase plasmid have been isolated frequently in Thailand (90).…”

Chancroid and Haemophilus ducreyi: an update

“…These plasmids have been reviewed in detail elsewhere (98). It is not unusual for a single H. ducreyi isolate to contain multiple resistance plasmids (45,136,137), including more than one plasmid that confers resistance to ␤-lactam antibiotics. Strains containing both a 7.0-MDa TEM-1 ␤-lactamase plasmid and a 3.5-MDa ROB-1 ␤-lactamase plasmid have been isolated frequently in Thailand (90).…”

Non-radioactive ribotyping ofHaemophilus ducreyiusing a digoxigenin labelled cDNA probe

“…ducreyi although several methods have been examined including protein profiles [4]. enzymic activity [5], lectin typing [0], indirect immunofluorescence [7] and plasmid analysis [8].…”