Tips from the journals of the American Society for Microbiology

Bacteria Found in Oral Cancer Tissue

For the first time, viable bacteria have been detected in oral cancer tissue say researchers from the United Kingdom. Their findings appear in the May 2006 issue of the Journal of Clinical Microbiology.

The sixth most common malignancy worldwide, oral cancer is particularly prevalent in developing countries at a rate of 40%. Recent studies show that the reported number of cases of oral cancer is increasing in many parts of the world in both men and women under the age of 45. The current average survival rate of 5 years at all stages is less than 50%, emphasizing the need for new methods of diagnosis and treatment.

In the study twenty deep-tissue samples were collected from patients undergoing surgery for oral cancer. The specimens were harvested from deep within the tumor mass using a fresh blade for each cut. Superficial portions and nontumorous samples were also collected as control specimens and surface contamination was maintained using Betadine and phosphate-buffered saline. Results showed a diverse group of bacteria, including several potentially novel species, of which some were isolated only from either the tumorous or nontumorous tissue.

"To our knowledge this is the first time that viable bacteria have been detected within the tissue of oral squamous cell carcinoma," say the researchers. "The significance of these bacteria within the tumor warrants further study."

(S.J. Hooper, S.J. Crean, M.A.O. Lewis, D.A. Spratt, W.G. Wade, M.J. Wilson. 2006. Viable bacteria present within oral squamous cell carcinoma tissue. Journal of Clinical Microbiology, 44. 5: 1719-1725.)

Production Practices Effect Antimicrobial Resistance in Poultry

The use of conventional versus organic production practices can significantly affect the prevalence of antibiotic resistant to bacteria in poultry say researchers from Maryland and Ohio. Their findings appear in the May 2006 issue of the journal Applied and Environmental Microbiology.

Campylobacter is one of the leading causes of food-borne illnesses worldwide, causing more than 2 million cases of bacterial diarrhea each year in the U.S. alone. Although most Campylobacter infections in humans are attributed to ingestion of contaminated foods, consumption of undercooked poultry or foods cross-contaminated with raw poultry meat also pose a major risk of campylobacteriosis. With incidences of food-borne illness on the rise, experts are also seeing an increase in antimicrobial resistance among the Campylobacter species. Currently, 19 to 40% of Campylobacter strains isolated in humans are resistant to ciproflaxin and this is attributed in part to the widespread use of antimicrobial agents in humans and animals.

In the study, researchers compared Campylobacter from the intestinal tracts of broilers and turkeys from conventional farms where antibiotics were routinely used and organic farms where antibiotics had never been used. A total of 694 Campylobacter isolates were tested for resistance to nine antibiotic agents. Researchers found that although Campylobacter species were dominant in both poultry operations, there was a significant difference in antibiotic resistance with a rate of less than 2% from organically raised poultry and 46 to 67% resistance from conventionally raised broilers and turkeys.

"This study revealed significant differences in antibiotic-resistant Campylobacter isolates between conventional poultry operations and organic poultry operations," say the researchers. "These results suggest that the practice of antibiotic usage in conventional poultry production systems influence the prevalence of antibiotic-resistant Campylobacter organisms in conventionally raised broilers and turkeys."

(T. Luangtongkum, T.Y. Morishita, A.J. Ison, S. Huang, P.F. McDermott, Q. Zhang. 2006. Effect of conventional and organic production practices on the prevalence and antimicrobial resistance of Campylobacter spp. in poultry. Applied and Environmental Microbiology, 72. 5: 3600-3607.)

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