ECHO-Antibiotic Stewardship Program More Interesting Recent Literature Updates April 20, 2017 Charles Krasner, M.D. University of NV, Reno School of Medicine Sierra NV Veterans Affairs Medical Center
Antibiotic use earlier in life associated with increased risk for colorectal adenoma(cancer precursor) Long term use of antibiotics and risk of colorectal adenoma. Cao et al. Gut 2017- online first, April 4, 2017 1 16,000 women in long term Nurses Health Study 2 3 4 5 Studied any association of antibiotic use at age 20-39, 40-59 and more recent Assessed prospectively for subsequent development of colorectal adenomas Found women who used >2 months total of antibiotics during these early time periods had significantly increased risk. No association with recent use Likely related to change in gut flora leading to biological pathways that initiate or promote colorectal neoplasia
Hepatitis C Transmission from inappropriate Reuse of Saline Flush Syringes for multiple Patients in an Acute Care General Hospital MMWR 2017, 66(9) 258-60 RN noted to frequently leave a partially filled syringe near her desk. She admitted to reusing saline syringes for 6 months. Thought this was a safe, cost saving measure as no fluids were withdrawn into the syringe before injecting the flush. Admitted was never taught to do this She worked on telemetry ward where all patients had required iv access Hospital notified Health Dep't, 392 patients sent registered letters- offered free HIV, HCV and HBV testing. 67% tracked down. One patient with known HCV was on her ward. This HCV was matched genetically to another patient there at same time (rare genotype, identical sequence, no other association between the two patient). Hospitals should use this as a teaching lesson and the need for ongoing oversite of safe injection practices at their facilities Deja vu all over again
Speaking of the Devil Dipak Desai M.D. died last week at Renown Med Center Ran a GI clinic in Las Vegas, did sham 2 minute colonoscopies on 1000s of patients, reused sheets, contaminated syringes, single dose vials. City closed his office in 2008 Made $200,000,000 fortune Infected over 100 patients with Hepatitis C Found guilty of murder in 2013 Never lost his license 13 of his practice associates still licensed in NV
Notes from the Field: An Outbreak of Salmonella Typhimurium Associated with Playground Sand in a Preschool Setting Madrid, Spain, September October 2016 MMWR / March 10, 2017 / 66(9);256 257 Over a 6 week period, 24 kids (out of 300 children in a school) developed severe gastroenteritis. All stool cultures were positive for non-typhi Salmonella No evidence for any source at the school- facilities, food, potable water, personnel. No animals kept at the school. Because of ongoing epidemic- a common source exposure identified- the sand lot- surrounded by trees that birds roost in. Multiple samples from the lot grew the strain seen in the kids. Previously only reported in wild and domestic birds. Closing the sandlot ended the epidemic
Elimination of Screening Urine Cultures Prior to Elective Joint Arthroplasty Michael J. Lamb et al. Clin Infect Dis (2017) 64 (6): 806-809. Screening urine cultures are frequently done prior to joint arthroplasty despite no evidence of clinical benefit, and puts patient at risk for harmdrug reaction, C. difficle, resistance Toronto Orthopedic hospital did prospective study where they eliminated preoperative urine cultures and observed for 2 years. 1891 cases were done, 3 post-op wound infections all staph aureus. No urinary pathogens isolated. No role for pre- op cultures unless patient is symptomatic
Determination of clinical significance of coagulase-negative staph in blood cultures Karakullukcu,A et al Diag Micro and Inf Dis 2017,2914. Coag neg Staph (such as Staph epidermidis) are normal skin flora and thus common contaminants found in blood cultures. Usually dismissed as contaminants when only 1 /4 bottles are positive Often considered true positive if 2/4 bottles are positive and the organisms are identical for species and susceptibility pattern (phenotypic identification) Genotyping of these phenotypically identical staph, however often show unrelated genetic fingerprinting More useful to identify true infection- clinical criteria including time to positivity, presence of SIRS criteria, and a likely source of infection such as a central line. Using 1 vs 2 positive cultures to determine clinical significance was not in itself diagnostic of true infection.
Association of gastric acid suppression with recurrent CDI Tariq,R et al. JAMA Internal Medicine March 27,2017 Meta analysis from Mayo Clinic and UCSD Identified 7,700 patients with CDI. Approx 20% developed recurrent CDI. 22% of those on acid blockers relapsed versus 17% not on these meds. Rates stayed the same adjusted for age and cofounding factors The take away from this study and previous reports: Acid blockers are not only a risk for catching CDI, but also for increasing risk for relapse. Worth reviewing their prophylaxis indications at your facilities, and are they being arbitrarily continued after hospitalization
Clostridium difficle rates in asymptomatic and symptomatic hospitalized patients using nucleic acid testing Truong, C. et al Diagn Microbiol Infect Dis 2017 April:87(4);365-70 Study at Stanford Hospital looked at C. diff Toxin gene + PCR rates in asymptomatic patients versus patients with diarrhea. 11.8% of asymptomatic patients were PCR+. 15.4% of patients with diarrhea were PCR+. No significant difference in these rates. No difference in PCR cycles to reach threshold positive. Conclusion: asymptomatic C. diff carriage rate was similar to symptomatic rate suggests the majority of PCR + results in symptomatic patients are likely due to colonization. Disease-specific biomarkers are needed to accurately diagnose patients with C. diff Disease
Remember. C.diff colitis (CDI) is foremost a Clinical Diagnosis that is only then confirmed by lab tests. It is not simply a + lab test result Watery diarrhea (Bristol 7) is the cardinal symptom of C. difficile associated diarrhea (CDI) with colitis ( 3 loose stools in 24 hours). Other manifestations include lower abdominal pain and cramping, low-grade fever, nausea, anorexia, and leukocytosis
C. Diff Lab Diagnosis- remember it is the toxin that causes the symptoms Direct culture- not used - $$$/slow turn around time C. diff PCR- positive test only tells you C. difficile carrying the toxin B gene is present in the stool. 100% sensitive, but DOES NOT differentiate between those c.diff that are secreting the toxin and those that are not. Whether or not toxin is actually being secreted, the PCR test will be positive+ ELISA- Answers the question if the C. diff is actually producing toxin and causing disease? detects both the presence of C. difficile bacteria (GDH Ag) as well as detects toxin A +/- toxin B.
Lab comment given with C. diff PCR and Toxin results The clostridium difficile PCR test detects the toxin gene but not the actual presence of toxin. A positive PCR toxin test therefore does not differentiate between asymptomatic colonization and active disease. When the PCR test is positive, additional tests will be automatically performed which detect both C. difficile antigen (GDH) and the A and B toxin. These tests may be used in conjunction with the patient history as an aid in the diagnosis and treatment of C. difficile disease. Indeterminate results suggest testing be repeated on a fresh specimen