Linking Epidemiology and Whole-Genome Sequencing to Investigate Salmonella Outbreak, Massachusetts, USA, 2018.

Cross-discipline collaboration among state and local health departments improved foodborne illness surveillance for a 2018 Salmonella enterica serovar Enteritidis outbreak in Massachusetts, USA. Prompt linking of epidemiologic and laboratory data and implementation of in-state whole-genome sequencing and analysis improved public health surveillance capacity for outbreak detection and control.

Candida auris outbreak involving liver transplant recipients in a surgical intensive care unit.

Candida auris is a yeast that is difficult to eradicate and has caused outbreaks in health care facilities. We report a cluster of 5 patients in 1 intensive care unit who were colonized or infected in 2017. The initial 2 patients were recipients of liver transplants who had cultures that grew C auris within 3 days of each other in June 2017 (days 43 and 30 posttransplant). Subsequent screening cultures identified 2 additional patients with C auris colonization. Respiratory and urine cultures from a fifth patient yielded C auris. All isolates were fluconazole resistant but susceptible to echinocandins. Whole genome sequencing showed the strains were clonal, suggesting in-hospital transmission, and related but distinct from New York/New Jersey strains, consistent with a separate introduction. However, no source or contact was found. Two of the 5 patients died. C auris infection likely contributed to 1 patient death by infecting a vascular aneurysm at the graft anastomosis. Strict infection control precautions were initiated to control the outbreak. Our experience reveals that although severe disease from C auris can occur in transplant recipients, outbreaks can be controlled using recommended infection control practices. We have had no further patients infected with C auris to date.

Opioid Use Fueling HIV Transmission in an Urban Setting: An Outbreak of HIV Infection Among People Who Inject Drugs-Massachusetts, 2015-2018.

Objectives. To describe and control an outbreak of HIV infection among people who inject drugs (PWID).Methods. The investigation included people diagnosed with HIV infection during 2015 to 2018 linked to 2 cities in northeastern Massachusetts epidemiologically or through molecular analysis. Field activities included qualitative interviews regarding service availability and HIV risk behaviors.Results. We identified 129 people meeting the case definition; 116 (90%) reported injection drug use. Molecular surveillance added 36 cases to the outbreak not otherwise linked. The 2 largest molecular groups contained 56 and 23 cases. Most interviewed PWID were homeless. Control measures, including enhanced field epidemiology, syringe services programming, and community outreach, resulted in a significant decline in new HIV diagnoses.Conclusions. We illustrate difficulties with identification and characterization of an outbreak of HIV infection among a population of PWID and the value of an intensive response.Public Health Implications. Responding to and preventing outbreaks requires ongoing surveillance, with timely detection of increases in HIV diagnoses, community partnerships, and coordinated services, all critical to achieving the goal of the national Ending the HIV Epidemic initiative.

Reversion From Methicillin Susceptibility to Methicillin Resistance in Staphylococcus aureus During Treatment of Bacteremia.

Approximately 3% of Staphylococcus aureus strains that, according to results of conventional phenotypic methods, are highly susceptible to methicillin-like antibiotics also have polymerase chain reaction (PCR) results positive for mecA. The genetic nature of these mecA-positive methicillin-susceptible S. aureus (MSSA) strains has not been investigated. We report the first clearly defined case of reversion from methicillin susceptibility to methicillin resistance among mecA-positive MSSA within a patient during antibiotic therapy. We describe the mechanism of reversion for this strain and for a second clinical isolate that reverts at a similar frequency. The rates of reversion are of the same order of magnitude as spontaneous resistance to drugs like rifampicin. When mecA is detected by PCR in the clinical laboratory, current guidelines recommend that these strains be reported as resistant. Because combination therapy using both a ß-lactam and a second antibiotic suppressing the small revertant population may be superior to alternatives such as vancomycin, the benefits of distinguishing between mecA-positive MSSA and MRSA in clinical reports should be evaluated.

Campylobacter fetus subsp. testudinum subsp. nov., isolated from humans and reptiles.

A polyphasic study was undertaken to determine the taxonomic position of 13 Campylobacter fetus-like strains from humans (n = 8) and reptiles (n = 5). The results of matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) MS and genomic data from sap analysis, 16S rRNA gene and hsp60 sequence comparison, pulsed-field gel electrophoresis, amplified fragment length polymorphism analysis, DNA-DNA hybridization and whole genome sequencing demonstrated that these strains are closely related to C. fetus but clearly differentiated from recognized subspecies of C. fetus. Therefore, this unique cluster of 13 strains represents a novel subspecies within the species C. fetus, for which the name Campylobacter fetus subsp. testudinum subsp. nov. is proposed, with strain 03-427(T) ( = ATCC BAA-2539(T) = LMG 27499(T)) as the type strain. Although this novel taxon could not be differentiated from C. fetus subsp. fetus and C. fetus subsp. venerealis using conventional phenotypic tests, MALDI-TOF MS revealed the presence of multiple phenotypic biomarkers which distinguish Campylobacter fetus subsp. testudinum subsp. nov. from recognized subspecies of C. fetus.

The role, challenges, and support of pulsenet laboratories in detecting foodborne disease outbreaks.

In recent years, there have been several high-profile nationwide foodborne outbreaks due to enteric organisms in food products, including Salmonella Typhimurium in peanut products, Salmonella Saintpaul in peppers, and Escherichia coli O157:H7 in spinach. PulseNet, the national molecular subtyping network for foodborne disease surveillance, played a key role in detecting each of these outbreaks. PulseNet laboratories use bacterial subtyping methods to rapidly detect clusters of foodborne disease, which are often the first indication that an outbreak is occurring. Rapid outbreak detection reduces ongoing transmission through product recalls, restaurant closures, and other mechanisms. By greatly increasing the sensitivity of outbreak detection, PulseNet allows us to identify and correct problems with our food production and distribution systems that would not otherwise have come to our attention. Annually, millions of potentially preventable cases of foodborne illness result in billions of dollars in lost productivity and health-care expenses. We describe the critical role PulseNet laboratories play in the detection of foodborne outbreaks and discuss current challenges and potential improvements for PulseNet laboratories to more rapidly identify future foodborne outbreaks.

4th generation HIV screening in Massachusetts: a partnership between laboratory and program.

BACKGROUND: The Massachusetts Department of Public Health's (MDPH) Office of HIV/AIDS (OHA) and Hinton State Laboratory Institute (HSLI) have offered HIV screening since 1985. Point-of-care screening and serum collection for laboratory-based testing is conducted at clinic and non-clinic-based sites across Massachusetts as part of an integrated communicable disease screening intervention. OBJECTIVES AND PROJECT DESIGN: MDPH aimed to transition to a 4th generation HIV screening-based algorithm for testing all serum specimens collected at OHA-funded programs and submitted to the HSLI to detect acute HIV infections, detect and differentiate HIV-1 and HIV-2 infections, eliminate indeterminate results, reduce cost and turnaround time, and link newly diagnosed HIV+ individuals to care. The HSLI and OHA created a joint project management team to plan and lead the transition. RESULTS: The laboratory transitioned successfully to a 4th generation screening assay as part of a revised diagnostic algorithm. In the 12 months since implementation, a total of 7984 serum specimens were tested with 258 (3.2%) positive for HIV-1 and one positive for HIV-2. Eight were reported as acute HIV-1 infections. These individuals were linked to medical care and partner services in a timely manner. Turnaround time was reduced and the laboratory realized an overall cost savings of approximately 15%. CONCLUSIONS: The identification of eight acute HIV infections in the first year underscores the importance of using the most sensitive screening tests available. A multi-disciplinary program and laboratory team was critical to the success of the transition, and the lessons learned may be useful for other jurisdictions.