Detection of Salmonella spp. in retail meat products: a comparison between a discontinued commercial kit and a laboratory-developed screening method.

The National Antimicrobial Resistance Monitoring System for Enteric Bacteria retail food surveillance programme screens retail meat samples for the presence of Salmonella spp. to track antimicrobial resistance in food. In this study, a laboratory developed real-time PCR assay that detects Salmonella spp. was evaluated as a screening method to replace the discountinued 3M TECRA kit. The 3M TECRA kit was a commercially available, visual immunoassay used to screen food samples for the presence of Salmonella spp. This kit was discontinued in September 2016 by the manufacturer and an alternative screening method was needed to replace the discontinued TECRA kit. Salmonella spp. is detected by the real-time PCR assay earlier in the screening process than by the TECRA kit. Salmonella spp. can also be reliably isolated from the enrichment broth earlier in the protocol. Additionally, cost analysis shows that the real-time PCR assay saves $2·50 per sample. New York State Department of Health currently uses this real-time PCR assay as a screening method for the presence of Salmonella spp. in retail meat samples. The assay allows for continued monitoring of antimicrobial resistance in Salmonella spp., while providing a cost savings and a decrease in turnaround time. SIGNIFICANCE AND IMPACT OF THE STUDY: The National Antimicrobial Resistance Monitoring System for Enteric Bacteria (NARMS) tracks antimicrobial susceptibility of enteric bacteria in people, food and animals (https://www.fda.gov/animalveterinary/safetyhealth/antimicrobialresistance/nationalantimicrobialresistancemonitoringsystem/). The New York State Department of Health (NYSDOH) became a NARMS retail food surveillance (RFS) site in 2003. The NARMS-RFS programme screens retail meat samples from grocery stores in the United States for the presence of Salmonella spp. and other enteric pathogens to monitor the prevalence of antimicrobial resistance among these pathogens. The NYSDOH developed a rapid and cost-effective real-PCR assay to screen for Salmonella spp. in retail meat products.

Premarket evaluations of the IMDx C. difficile for Abbott m2000 Assay and the BD Max Cdiff Assay.

Clostridium difficile-associated diarrhea is a well-recognized complication of antibiotic use. Historically, diagnosing C. difficile has been difficult, as antigen assays are insensitive and culture-based methods require several days to yield results. Nucleic acid amplification tests (NAATs) are quickly becoming the standard of care. We compared the performance of two automated investigational/research use only (IUO/RUO) NAATs for the detection of C. difficile toxin genes, the IMDx C. difficile for Abbott m2000 Assay (IMDx) and the BD Max Cdiff Assay (Max). A prospective analysis of 111 stool specimens received in the laboratory for C. difficile testing by the laboratory's test of record (TOR), the BD GeneOhm Cdiff Assay, and a retrospective analysis of 88 specimens previously determined to be positive for C. difficile were included in the study. One prospective specimen was excluded due to loss to follow-up discrepancy analysis. Of the remaining 198 specimens, 90 were positive by all three methods, 9 were positive by TOR and Max, and 3 were positive by TOR only. One negative specimen was initially inhibitory by Max. The remaining 95 specimens were negative by all methods. Toxigenic C. difficile culture was performed on the 12 discrepant samples. True C. difficile-positive status was defined as either positive by all three amplification assays or positive by toxigenic culture. Based on this definition, the sensitivity and specificity were 96.9% and 95% for Max and 92.8% and 100% for IMDx. In summary, both highly automated systems demonstrated excellent performance, and each has individual benefits, which will ensure that they will both have a niche in clinical laboratories.

Public health approach to detection of non-O157 Shiga toxin-producing Escherichia coli: summary of two outbreaks and laboratory procedures.

Routine laboratory testing may not detect non-O157 Shiga toxin-producing Escherichia coli (STEC) reliably. Active clinical, epidemiological, environmental health, and laboratory collaboration probably influence successful detection and study of non-O157 STEC infection. We summarized two outbreak investigations in which such coordinated efforts identified non-O157 STEC disease and led to effective control measures. Outbreak 1 involved illness associated with consuming unpasteurized apple cider from a local orchard. Public health personnel were notified by a local hospital; stool specimens from ill persons contained O111 STEC. Outbreak 2 involved bloody diarrhoea at a correctional facility. Public health personnel were notified by the facility infection control officer; O45 STEC was the implicated agent. These reports highlight the ability of non-O157 STEC to cause outbreaks and demonstrate that a coordinated effort by clinicians, infection-control practitioners, clinical diagnostic laboratorians, and public health personnel can lead to effective identification, investigation, and prevention of non-O157 STEC disease.

Use of multiple-locus variable number tandem repeat analysis and phage typing for subtyping of Salmonella Enteritidis from sporadic human cases in the United States.

AIMS: To investigate the genetic diversity among S. Enteritidis isolates from different geographic regions to evaluate the relationship between phage types (PTs) and variable number tandem repeat analysis (VNTR) loci. METHODS AND RESULTS: We performed multiple-locus variable number tandem repeat analysis (MLVA) and phage typing on 245 S. Enteritidis isolates collected from sporadic human clinical cases in Michigan, Minnesota, New York, and Washington states between 2000 and 2007. Ninety-four MLVA types and 22 different PTs were identified. Specific PTs were associated with a predominant allele for certain VNTR loci. Cluster analysis using a minimum-spanning tree demonstrated two major clusters (I, II) and one minor cluster of isolates. PTs 8, 13a, 13 and 34 were significantly associated with MLVA cluster I. Phage types 1, 4, 6a, and 18 were significantly associated with MLVA cluster II. CONCLUSIONS: We found significant association between MLVA-based clusters and PTs. Certain VNTR loci were associated with specific PTs and could serve as useful molecular markers for S. Enteritidis in epidemiological investigations. SIGNIFICANCE AND IMPACT OF THE STUDY: MLVA genotyping in combination with phage typing can be used for effective characterization of S. Enteritidis isolates. It can also be useful for tracing possible sources during investigations of sporadic and outbreak cases of S. Enteritidis.

Community-associated methicillin-resistant Staphylococcus aureus skin infections in a religious community.

In September 2004, an outbreak of community-associated methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections (SSTI) was reported among members of a religious community. We conducted a retrospective cohort study on all 175 community members; performed a nasal carriage survey, and environmental swab testing. We identified 24 MRSA cases (attack rate 14%). In multivariate analysis, sauna use [odds ratio (OR) 19.1, 95% confidence interval (CI) 2.7-206.1] and antimicrobial use within 12 months before infection (OR 11.7, 95% CI 2.9-47.6) were risk factors for infection. MRSA nasal carriage rate was 0.6% (1/174). Nine of 10 clinical isolates and an isolate from an administrative office within the community had the pulsed-field gel electrophoresis type USA300. Targeted hygiene improvement, wound care, and environmental cleaning were implemented. We describe the first reported outbreak of MRSA SSTI in a religious community. Adherence to appropriate personal and environmental hygiene might be critical factors in controlling transmission.

Development of a genomics-based PCR assay for detection of Mycoplasma pneumoniae in a large outbreak in New York State.

A genomics-based PCR method was developed and used to test specimens from patients involved in a large outbreak of Mycoplasma pneumoniae in a closed religious community in New York State. New P1 adhesin gene primers were designed to bind to 9 of 10 target sequences in the repetitive-element sequences obtained from the whole genome sequence of M. pneumoniae. This PCR method had a sensitivity of 0.006 CFU and a specificity of 100% for M. pneumoniae. The PCR was validated by testing a subset of patient samples by culture and comparing the results to those obtained by PCR. Of the initial 280 samples tested, 73 were positive by PCR and 22 were positive by culture. All samples positive by culture were also positive by PCR. Follow-up testing of selected patients 3 to 6 weeks after antibiotic treatment revealed that eight samples remained positive by PCR and that three samples remained positive by culture. Additionally, no nonspecific PCR inhibition was detected as a result of the specimen type, transport medium, or sample preparation methodology. The study demonstrates that the PCR described here is a rapid, sensitive, and specific method for the identification of M. pneumoniae and was helpful for the detection and monitoring of the outbreak.

Changing home health care marketplace in Wisconsin.

The increasing percentage of frail, chronically ill, elderly in Wisconsin combined with a shift in the site of care delivery from institution to homes has created an increased need for non-skilled home health services. Despite recent increases in home health expenditures these increases in need are even greater. Tightening interpretations of Medicare eligibility criteria, the expansion of health maintenance organizations, and the vulnerability of county home health agencies in Wisconsin are limiting access to home care services for chronically ill elderly in the state.