University of Iowa Carver College of Medicine

TUESDAY, Sept. 3, 2024 -- Fecal immunochemical tests (FITs) have variable sensitivity and specificity for detecting advanced colorectal neoplasia (ACN), according to a study published online Sept. 3 in the Annals of Internal Medicine . Barcey T. Levy, M.D., Ph.D., from the University of Iowa Carver College of Medicine in Iowa City, and colleagues compared the performance characteristics of five commonly used FITs (with colonoscopy as the reference standard) in a cross-sectional study in three U.S. academic medical centers and affiliated endoscopy units. Participants aged 50 to 85 years completed five different FITs before colonoscopy: four qualitative tests (Hemoccult ICT, Hemosure iFOB, OC-Light S FIT, and QuickVue iFOB) and one quantitative test (OC-Auto FIT). Test performance for ACN, defined as advanced polyps or colorectal cancer (CRC), was the primary outcome. A total of 3,761 participants were enrolled in the study. The researchers found that 320 participants had ACN (8.5 percent), including nine (0.2 percent) with CRC. Test positivity varied from 3.9 to 16.4 percent across FITs. There was variation observed in the rates of unevaluable FITs, from 0.2 to 2.5 percent. For ACN, the sensitivity and specificity varied from 10.1 to 36.7 percent and from 85.5 to 96.6 percent, respectively. All differences in sensitivity between FITs were statistically significant apart from the difference between Hemosure iFOB and QuickVue iFOB, while all differences in specificity were statically significant. Distal location of ACN was also associated with higher FIT sensitivity. "Our findings have implications for the benefits and cost-effectiveness of CRC screening using FIT," the authors write.

New findings suggest that a probiotic combination could reduce incidence of toxic shock syndrome. The widespread, pathogenic microbe Staphylococcus aureus can colonize the skin and mucous membranes throughout the body, particularly the vagina and gastrointestinal tract. A virulent strain of the bacterium produces proteins that trigger toxic shock syndrome (TSS), a disease characterized by the quick onset of fever, a telltale rash, and, without treatment, multi organ failure. In the vagina, TSS is associated with a life-threatening reaction from the immune system. Probiotics may help prevent the disease before the cytokine cascade ever begins. A study published in the American Society for Microbiology's journal Microbiology Spectrum reports that strains of 2 bacteria, Lactobacillus acidophilus and Lacticaseibacillus rhamnosus, successfully inhibited the production of the superantigens that cause TSS, in lab experiments. L. acidophilus, in addition, inhibited the growth of the S. aureus strains that produce the problematic proteins. A combination of the 2 could both prevent growth and inhibit the immune response. "It's kind of a double whammy against S. aureus," said microbiologist Patrick Schlievert, Ph.D., at the University of Iowa Carver College of Medicine, in Iowa City. "If any toxin is made, the probiotics still prevent inflammation." He noted that adding these probiotics to tampons or other menstrual products could reduce the risk -- and global incidence -- of TSS associated with menstruation. Such a preventive measure has the potential to benefit millions of vulnerable people, Schlievert said. "We know that 20% of people over age 12 cannot make antibodies and never will make antibodies against toxic shock syndrome," he said. Schlievert has been studying TSS -- and its prevention -- for decades. In the early 1980s, he was the first researcher to identify the toxin that triggers an overreaction of the immune system, and to show how high-absorbency tampons facilitated production of that toxin if S. aureus was present. The new work, he said, was motivated by observations made during an earlier study. A few years ago, he and his colleagues recruited 205 women to test whether a novel molecular mixture, when added to tampons, would inhibit pathogenic bacteria. That molecule proved effective against E. coli and other pathogens, but the researchers noticed an unexpected consequence. "Some of the women in the treatment group had this tremendous growth of Lactobacilli," Schlievert said. Further studies revealed that 9 of those women were colonized with only L. crispatus and no other bacteria. In microbiology research, Schlievert said, colonization by a single bacterium is often regarded as unhealthy. In this case, however, it offered an effective action against pathogenic S. aureus. Lactobacillus bacteria have already been shown to be safe, Schlievert said, and the new work suggests that treatment with L. crispatus alone, or L. acidophilus and L. rhamnosus in combination, could dramatically reduce the risk of TSS in vulnerable populations. Strains of S. aureus can also cause enterocolitis, a life-threatening immune response in the gut. Probiotics may also help reduce the production of dangerous proteins for that disease, said Schlievert. In ongoing and future work, Schlievert and his team are investigating how to use probiotics to prevent skin staph infections. The skin of people with atopic dermatitis, or with type 2 diabetes, is often colonized with the strains of S. aureus that produce superantigens, which are often resistant to treatment with standard antibiotics. In patients with type 2 diabetes, those superantigens could lead to foot ulcers that, if not treated successfully, could lead to amputation. Schlievert sees probiotics as a promising way to prevent those complications. "If we can improve their lives by using this approach, that would be wonderful."

WEDNESDAY, July 5, 2023 -- Lower extremities have the highest rates of surgical site infections following Mohs micrographic surgery (MMS), according to a research letter published online June 24 in the Journal of the American Academy of Dermatology . Ailynna Chen, M.D., M.P.H., from the University of Iowa Carver College of Medicine in Iowa City, and colleagues conducted a systematic review to provide a quantitative estimate of SSI rates across different MMS closure techniques with stratification by body site. Based on 27 included reports, the researchers identified 2,252 flap/graft closures; 3,818 primary closures; and 1,434 secondary intention healing cases. The researchers observed a significant difference between body sites, with lower extremities having the highest SSI rates across all closure types. For head and neck, the pooled SSI rates were 0.01 for flap/graft closures, <0.01 for primary closure, and <0.01 for secondary intention healing; for lower extremity SSI, the corresponding rates were 0.11, 0.05, and 0.04. Except for one study with high risk of bias, studies had low-to-moderate risk of bias. "While previous studies suggest that heightened sterility practices (i.e., sterile gloves, single-use instruments, antibiotic prophylaxis) are generally unnecessary for MMS, closure type, body site, and other patient characteristics should also be considered," the authors write. Abstract/Full Text (subscription or payment may be required) Posted July 2023