Characterization and distribution of insertion sequence IS1239 in Streptococcus pyogenes

The human pathogenic bacterium Streptococcus pyogenes causes pharyngitis, acute rheumatic fever, glomerulonephritis and toxic-shock-like syndrome. The bacterium synthesizes several extracellular products, including the recently described streptococcal superantigen SSA, a molecule that shares considerable homology with several Staphylococcus aureus enterotoxins. While studying allelic variation at the ssa locus, six isolates expressing serotypes M4, M23, M33, M41, M43, and provisional type PT4854, were identified that had PCR products about 40-bp larger than expected, and one isolate (M15) had an amplified fragment that was more than 1-kb larger than expected. All six isolates have a 34-bp insert located 103 bp 5' of the ssa start codon. The larger product is a result of a 1110-bp insertion at the analogous location. The complementary strand of this insert has a 981-bp open reading frame that potentially encodes a 326-amino-acid polypeptide with substantial homology to the Escherichia coli IS30 transposase. Results of Southern blot analysis showed that at least twelve copies of the sequence are present in the serotype M15 S. pyogenes isolate. This element, designated IS1239, is the first simple insertion sequence described in group-A streptococci. Results of PCR screening showed that 26 of 78 (33%) S. pyogenes isolates expressing distinct M protein serotypes contained sequences with homology to IS1239, which means that the element is widely distributed in the species.

Epidemiology of penicillin-resistant Neisseria gonorrhoeae isolated in Taiwan, 1960-1990

The epidemiology of penicillin-susceptible Neisseria gonorrhoeae isolated in Taiwan from 1960 to 1990 is summarized. The isolation of N. gonorrhoeae less sensitive to penicillin (i.e., with intrinsic resistance) was first reported in 1960. The rate at which organisms less sensitive to penicillin (MIC, greater than or equal to 0.5 microgram/mL) were isolated increased to 17%, 50%, 80.1%, and 88.8% in 1967, 1975, 1984, and 1990, respectively. Penicillinase-producing N. gonorrhoeae (PPNG) first appeared in Taiwan in late 1976, and the first six strains of PPNG isolated were from United States military servicemen who had relocated from Southeast Asia. The percentage of PPNG strains rose to 37.82% in 1982, and has remained high (50%-62%) since 1983. In the present study, resistance of N. gonorrhoeae to spectinomycin (MIC, greater than 32 micrograms/mL), third-generation cephalosporins (MIC, greater than 4 micrograms/mL), or quinolones (MIC, greater than 4 micrograms/mL) has not been found. Strains requiring arginine, hypoxanthine, and uracil for growth, which frequently cause disseminated gonococcal infections, were not isolated. PPNG strains tended to be of the prototrophic auxotype (55%); non-PPNG strains were mostly of the proline-requiring auxotype (48.8%). Two kinds of R plasmids were isolated in the PPNG strains: the 4.4-MD Asian type (82%-95%) and the 3.05-MD Toronto type (5%-18%). All of the PPNG strains possessing Toronto R plasmid were of the same auxotype/serotype (prototrophic/IB). Evidence suggests that the Asian-type R plasmid was imported into Taiwan in 1976, while the Toronto-type R plasmid may have first emerged in Taiwan in 1983.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of plasmid pattern in paediatric intensive care unit outbreaks of nosocomial infection due to Enterobacter cloacae

Sequential outbreaks of nosocomial infection due to multiply-resistant Enterobacter cloacae occurred in September 1987, and between December 1988 and January 1989, in a paediatric intensive care unit. A total of eight neonates were affected and most had received ventilatory support. Initially, we were unable to determine whether the two outbreaks were caused by the same strain of E. cloacae. After applying plasmid profile analysis to identify epidemic strains, we established that the strain from the first outbreak was different from the second outbreak strain, as each had its own plasmid pattern. During the second outbreak, an environmental bacteriological survey was carried out. We found that the distilled water containers were contaminated with E. cloacae which had the same plasmid profile. After changing the distilled water containers and by reinforcement of aseptic techniques, the nosocomial outbreak was terminated.

[Epidemiological characterization of Neisseria gonorrhoeae isolates from Taiwan. Part II: Distribution of auxotyping, serogrouping and plasmid profile]

Epidemiology of gonococcal infection in Taiwan was investigated. Six hundred twelve isolates from 7 cities in 1983-1984 were examined for auxotyping by Hendry and Stewart's method, for serotyping by coagglutination of monoclonal antibodies with the antigenic specificity of gonococcal protein I molecules and for plasmid profile by the alkaline quick method. The results are described below: (1) Thirty-six auxotypes were found. Prototropic (Prototype) 45.4% (284/612) and Proline type (Pro) 38.7% (237/612) were the two dominant auxotypes. Arg- Hyp- Ura- which was thought to be correlated with disseminated gonococcal infection was not found. (2) Fifty-five percent penicillinase producing Neisseria gonorrheal (PPNG) were prototype and 48.8% non-PPNG were Pro. (3) Sixteen serotypes were identified among 56 strains. There was 17.8 (10/56 which belonged to the IA group and 82.2% (46/56) to the IB group. (4) Five molecular weight plasmids were found. They were 2.6 Mdal, 3.05 Mdal, 4.7 Mdal, 7.8 Mdal and 24.5 Mdal. (5) There were 7 plasmid profiles including 2.6 Mdal (26.4%); 2.6 Mdal +24.5 Mdal (23.2%); 2.6 Mdal+7.8 Mdal+24.5 Mdal (0.4%); 2.6 Mdal+4.7 Mdal (8.9%); 2.6 Mdal+4.7 Mdal+24.5 Mdal (38.2%); 2.6 Mdal+4.7 Mdal+24.5 Mdal (0.2%) and 2.6 Mdal+3.05 Mdal+24.5 Mdal (2.4%). (6) All the isolates harbored cryptic 2.6 Mdal plasmid. Eighty three percent of the PPNG and 48.6% of the non-PPNG harbored 24.5 Mdal plasmid. Twelve out of 305 PPNG isolates were "Toronto" type 3.05 Mdal plasmid. Others were "Asian" 4.7 Mdal plasmid. There were no "African" type 3.2 Mdal plasmids found.