Use of Proton Pump Inhibitors and the Risk of Listeriosis: A Nationwide Registry-based Case-Control Study.

BACKGROUND: Recent studies suggest that proton pump inhibitors (PPIs) may increase the risk for listeriosis. We investigated a potential association in cases of nonpregnancy-associated listeriosis using registry data. METHODS: We conducted a population-based, case-control study using Danish health registries. Cases (n = 721) were defined as patients aged ≥45 years notified with listeriosis from July 1994 to December 2012. We selected 34800 controls using risk-set sampling. Controls were individually matched for age, sex, and municipality. Data on use of PPIs and other drugs and hospitalization diagnoses over a 5-year period were extracted from nationwide health registries. A comorbidity index (CMI) was constructed. We calculated the association between use of PPIs and related drugs within 30 days (current use) and other time windows before the index date. Using conditional logistic regression, matched odds ratios (ORs) adjusted for CMI and confounders were estimated. RESULTS: The adjusted OR for current use of PPIs and development of listeriosis was 2.81 (95% confidence interval [CI], 2.14-3.69). PPI usage up to 90 days before the index date remained statistically significant. Subgroup analyses revealed increasing ORs with decreasing age and level of comorbidity and an increased OR for concurrent glucocorticoid treatment (OR, 4.61; 95% CI, 3.01-7.06). No significant association was found for current use of histamine-2-receptor antagonists (adjusted OR, 1.82; 95% CI, 0.89-3.71). CONCLUSIONS: Prescribed PPIs were associated with increased risk of listeriosis. The risk waned with time since last prescription redemption. PPIs may have unwanted side effects in vulnerable populations.

Whole-genome Sequencing Used to Investigate a Nationwide Outbreak of Listeriosis Caused by Ready-to-eat Delicatessen Meat, Denmark, 2014.

BACKGROUND: Listeriosis is a serious foodborne infection. Outbreaks of listeriosis occur rarely, but have often proved difficult to solve. In June 2014, we detected and investigated a listeriosis outbreak in Denmark using patient interviews and whole-genome sequencing (WGS). METHODS: We performed WGS on Listeria monocytogenes isolates from patients and available isolates from ready-to-eat foods and compared them using single-nucleotide polymorphism (SNP) analysis. Case patients had L. monocytogenes with ≤3 SNPs (the outbreak strain) isolated in September 2013-December 2014. Through interviews, we established case patients' food and clinical histories. Food production facilities were inspected and sampled, and we performed trace-back/trace-forward of food delivery chains. RESULTS: In total, 41 cases were identified; 17 deaths occurred (41%). An isolate from a delicatessen meat (spiced meat roll) from company A was identical to the outbreak strain. Half of the patients were infected while hospitalized/institutionalized; institutions were supplied food by company A. The outbreak strain was repeatedly isolated from further samples taken within this company and within companies in its distribution chain. Products from company A were traced and recalled from >6000 food establishments, after which the outbreak ended. CONCLUSIONS: Ready-to-eat spiced meat roll from a single production facility caused this outbreak. The product, served sliced and cold, is popular among the elderly; serving it at hospitals probably contributed to the high case-fatality rate. WGS used for patient isolates and isolates from food control inspections, coupled with routine epidemiological follow-up, was instrumental in swiftly locating the source of infections, preventing further illnesses and deaths.

Mass spectrometry: pneumococcal meningitis verified and Brucella species identified in less than half an hour.

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently being introduced for the rapid and accurate identification of bacteria. We describe 2 MALDI-TOF MS identification cases - 1 directly on spinal fluid and 1 on grown bacteria. Rapidly obtained results had great value for the continued treatment and for the elucidation of exposure.