[Molecular subtyping of Staphylococcus aureus isolated from a severe food-poisoning].

OBJECTIVE: To study the molecular types of Staphylococcus aureus isolated from a severe food-poisoning and to trace the possible strains. METHODS: Real-time PCR was applied to detect nuc gene as a specific marker for S. aureus, mecA gene encoding methicillin resistance and 5 other genes encoding staphylococcal enterotoxins (sea, seb, see, sed, see). Isolates were also performed with 16S rRNA oligonucleotide sequence analyzing by DNAStar MegAlign 5.0 software and pulse-field gel electrophoresis (PFGE) by BioNumerics Version 4.0 software. RESULTS: The nuc gene was detected from the 10 isolated strains, sea and seb genes were detected from 7 strains. There were 4 16 S rRNA types and 5 PFGE types found from all the strains. CONCLUSIONS: Three relative S. aureus strains were involved in the severe food-poisoning at least. Molecular subtyping might give a molecular epidemiological evidence and support the source tracing of an outbreak.

[Phylogenetic analysis and PCR-restriction fragment length polymophism identification of Salmonella based on grOEL gene sequence].

OBJECTIVE: To investigate the value of grOEL gene sequence in phylogenetic analysis and typing of Salmonella. METHODS: The grOEL gene was amplified by PCR, sequenced and analyzed using Bioedit and DNAstar software. The Salmonella strains were identified using PCR-restriction fragment length polymophism (PCR-RFLP). RESULTS: The conservative and variable regions of grOEL gene of Salmonella serogroup were separately distributed and most of the small mutant regions distributed intermittently among the conservative regions. The phylogenetic tree of Salmonella based on the nucleotides differed from that generated based on the amino acid sequence. O8, O9 and O10 had the closest consanguinity, and 5 patterns were identified by PCR-RFLP. CONCLUSION: The grOEL gene can be used as a genetic marker for phylogenetic analysis of Salmonella and also as a target sequence for Salmonella typing identification.

[Distribution and molecular epidemiologic characterizes of insertion sequence IS1301 in neisseria meningitidis isolated from China].

OBJECTIVE: To research the distribution and molecular epidemiology of insertion sequence IS1301 in Neisseria (N.) meningitidis strains in China, so as to provide scientific and available evidence for a new method of genotyping in N. meningitidis strains with IS1301. METHODS: Examined the IS1301 by PCR in 219 N.meningitidis strains from 16 provinces and 3 cities during 2007 and 2008 in China, productions of amplification were sent for sequencing. The positive N. meningitidis strains were analyzed by pulse field gel electrophoresis (PFGE) and nucleic acid blotting hybridization(Southern blot) by electrophoresis. RESULTS: The positive rates with IS1301 were 15.53%, 11.11%, 20.75%,6.17% and 28.57% for four serotypes (A, B, C, N) respectively. The sequence comparability between the amplification productions and No.Z49092.1 N. meningitidis which registered in GenBank was 94%-100%. There were two types of clusters divided by cladogram analysis. There appeared large IS1301 sequence difference between the serotype C and others. The number of IS1301 replica ranged from 6-17 per strain at least. The number of IS1301 replica changed in the same type of PFGE N. meningitidis respectively. CONCLUSION: Typing by IS1301 combined with PFGE could comprehend the homology and genetic polymorphism of N.meningitidis epidemic strains at the molecular level.

Mycobacterium abscessus post-injection abscesses from extrinsic contamination of multiple-dose bottles of normal saline in a rural clinic.

BACKGROUND: We investigated an outbreak of gluteal abscesses following intramuscular (IM) injections given at a clinic in rural China to identify the causative agent, source, and method of exposure. METHODS: We defined a case as an abscess that appeared at the site of an injection given since June 1, 2006. We compared case rates by injection route, medication, and diluents. We reviewed injection practices, and cultured abscesses and environmental sites for mycobacteria. RESULTS: From October through December 2006, 5.8% (n=35) of 604 persons who had received injections at the clinic developed a case. All 35 cases occurred in 184 patients (attack rate=19.0%) who had received IM injections with various drugs that had been mixed with normal saline (NS); risk ratio=infinity; p<0.0001. No cases occurred in the absence of NS exposure. We identified Mycobacterium abscessus from eight abscesses and from the clinic water supply, and observed the inappropriate reuse of a 16-gauge needle left in the rubber septum of 100 ml multiple-dose bottles of NS in the clinic. Fourteen percent (n=527) of the 3887 registered residents of this village had been treated with IM drugs over a three-month period, often for minor illnesses. CONCLUSIONS: This outbreak of M. abscessus occurred from exposure to extrinsically contaminated NS through improper injection practices. Frequent treatment of minor illnesses with IM injections of antibiotics was likely an important contributing factor to the size of this outbreak.