PCR primers for the detection of staphylococcal enterotoxins K, L, and M and survey of staphylococcal enterotoxin types in Staphylococcus aureus isolates from food poisoning cases in Taiwan.
Staphylococcal enterotoxins (SEs) are important causative agents in gastroenteritidis and food poisoning cases. They are serologically grouped into five major classical types, i.e., SEA, SEB, SEC, SED, and SEE. In addition, new SEs, such as SEG through SEM, have recently been identified and characterized. In an attempt to survey the distribution of classical and new SEs in organisms responsible for staphylococcal infections in Taiwan, we developed PCR primers for the genes that define the SEK, SEL, and SEM types. Bacterial strains other than sek, sel, and sem Staphylococcus aureus, including strains of other Staphylococcus species, did not generate any false-positive results when examined with these primers. The expression potential for the sek, sel, and sem types were also determined by reverse transcription-PCR. Together with the PCR primers specific for the classical SEs and other new SEs, including SEG, SEH, SEI, and SEJ, we surveyed the SE genes in S. aureus strains isolated from food poisoning cases. For 147 S. aureus isolates originating from food poisoning cases, 109 (74.1%) were positive for one or more SE genes. Of them, the major classical enterotoxin type was sea (28.6%), followed by seb (20.4%), sec (8.2%), and sed (2.0%). For the new SE types, sei (30.6%) was detected the most often, followed by sek (18.4%), sem (12.9%), and sel (8.2%). Also, 64 (43.5%) of the total bacterial strains had more than one enterotoxin gene.
Chiang
Yu-Cheng
YC
Department of Food Science, National Chung-Hsing University, 250 Kuo-Kuang Road, Taichung, Taiwan, Republic of China.
Chang
Li-Tung
LT
Lin
Chia-Wei
CW
Yang
Chi-Yea
CY
Tsen
Hau-Yang
HY
D001483:Base Sequence; D017931:DNA Primers; D004768:Enterotoxins / Q000235:genetics / Q000302:isolation & purification*; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013202:Staphylococcal Food Poisoning / Q000175:diagnosis / Q000382:microbiology*; D013210:Staphylococcus / Q000302:isolation & purification / Q000378:metabolism; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000378:metabolism; D013624:Taiwan
D017931:DNA Primers; D004768:Enterotoxins