Characterization of LrgAB as a stationary phase-specific pyruvate uptake system in Streptococcus mutans.

BACKGROUND: Our recent '-omics' comparisons of Streptococcus mutans wild-type and lrgAB-mutant revealed that this organism undergoes dynamic cellular changes in the face of multiple exogenous stresses, consequently affecting its comprehensive virulence traits. In this current study, we further demonstrate that LrgAB functions as a S. mutans pyruvate uptake system. RESULTS: S. mutans excretes pyruvate during growth as an overflow metabolite, and appears to uptake this excreted pyruvate via LrgAB once the primary carbon source is exhausted. This utilization of excreted pyruvate was tightly regulated by glucose levels and stationary growth phase lrgAB induction. The degree of lrgAB induction was reduced by high extracellular levels of pyruvate, suggesting that lrgAB induction is subject to negative feedback regulation, likely through the LytST TCS, which is required for expression of lrgAB. Stationary phase lrgAB induction was efficiently inhibited by low concentrations of 3FP, a toxic pyruvate analogue, without affecting cell growth, suggesting that accumulated pyruvate is sensed either directly or indirectly by LytS, subsequently triggering lrgAB expression. S. mutans growth was inhibited by high concentrations of 3FP, implying that pyruvate uptake is necessary for S. mutans exponential phase growth and occurs in a Lrg-independent manner. Finally, we found that stationary phase lrgAB induction is modulated by hydrogen peroxide (H2O2) and by co-cultivation with H2O2-producing S. gordonii. CONCLUSIONS: Pyruvate may provide S. mutans with an alternative carbon source under limited growth conditions, as well as serving as a buffer against exogenous oxidative stress. Given the hypothesized role of LrgAB in cell death and lysis, these data also provide an important basis for how these processes are functionally and mechanically connected to key metabolic pathways such as pyruvate metabolism.

Regulation of cid and lrg expression by CcpA in Streptococcus mutans.

The Streptococcus mutans Cid/Lrg system represents an ideal model for studying this organism's ability to withstand various stressors encountered in the oral cavity. The lrg and cid operons display distinct and opposite patterns of expression in response to growth phase and glucose levels, suggesting that the activity and regulation of these proteins must be tightly coordinated in the cell and closely associated with metabolic pathways of the organism. Here, we demonstrate that expression of the cid and lrg operons is directly mediated by a global transcriptional regulator CcpA in response to glucose levels. Comparison of the cid and lrg promoter regions with the conserved CcpA binding motif revealed the presence of two potential cre sites (for CcpA binding) in the cid promoter (designated cid-cre1 and cid-cre2), which were arranged in a similar manner to those previously identified in the lrg promoter region (designated lrg-cre1 and lrg-cre2). We demonstrated that CcpA binds to both the cid and lrg promoters with a high affinity, but has an opposing glucose-dependent effect on the regulation of cid (positive) and lrg (negative) expression. DNase I footprinting analyses revealed potential binding sequences for CcpA in both cid and lrg promoter regions. Collectively, these data suggest that CcpA is a direct regulator of cid and lrg expression, and are suggestive of a potential mechanism by which Cid/Lrg-mediated virulence and cellular homeostasis is integrated with signals associated with both the environment and cellular metabolic status.

From Punishment to Treatment: The "Clinical Alternative to Punitive Segregation" (CAPS) Program in New York City Jails.

The proliferation of jails and prisons as places of institutionalization for persons with serious mental illness (SMI) has resulted in many of these patients receiving jail-based punishments, including solitary confinement. Starting in 2013, the New York City (NYC) jail system developed a new treatment unit for persons with SMI who were judged to have violated jail rules (and previously would have been punished with solitary confinement) called the Clinical Alternative to Punitive Segregation (CAPS) unit. CAPS is designed to offer a full range of therapeutic activities and interventions for these patients, including individual and group therapy, art therapy, medication counseling and community meetings. Each CAPS unit requires approximately $1.5 million more investment per year, largely in additional staff as compared to existing mental health units, and can house approximately 30 patients. Patients with less serious mental illness who received infractions were housed on units that combined solitary confinement with some clinical programming, called Restrictive Housing Units (RHU). Between 1 December 2013 and 31 March 2015, a total of 195 and 1433 patients passed through the CAPS and RHU units, respectively. A small cohort of patients experienced both CAPS and RHU (n = 90). For these patients, their rates of self-harm and injury were significantly lower while on the CAPS unit than when on the RHU units. Improvements in clinical outcomes are possible for incarcerated patients with mental illness with investment in new alternatives to solitary confinement. We have started to adapt the CAPS approach to existing mental health units as a means to promote better clinical outcomes and also help prevent jail-based infractions. The cost of these programs and the dramatic differences in length of stay for patients who earn these jail-based infractions highlight the need for alternatives to incarceration, some of which have recently been announced in NYC.

Disparities in Mental Health Referral and Diagnosis in the New York City Jail Mental Health Service.

OBJECTIVES: To better understand jail mental health services entry, we analyzed diagnosis timing relative to solitary confinement, nature of diagnosis, age, and race/ethnicity. METHODS: We analyzed 2011 to 2013 medical records on 45,189 New York City jail first-time admissions. RESULTS: Of this cohort, 21.2% were aged 21 years or younger, 46.0% were Hispanic, 40.6% were non-Hispanic Black, 8.8% were non-Hispanic White, and 3.9% experienced solitary confinement. Overall, 14.8% received a mental health diagnosis, which was associated with longer average jail stays (120 vs 48 days), higher rates of solitary confinement (13.1% vs 3.9%), and injury (25.4% vs 7.1%). Individuals aged 21 years or younger were less likely than older individuals to receive a mental health diagnosis (odds ratio [OR] = 0.86; 95% confidence interval [CI] = 0.80, 0.93; P < .05) and more likely to experience solitary confinement (OR = 4.99; 95% CI = 4.43, 5.61; P < .05). Blacks and Hispanics were less likely than Whites to enter the mental health service (OR = 0.57; 95% CI = 0.52, 0.63; and OR = 0.49; 95% CI = 0.44, 0.53; respectively; P < .05), but more likely to experience solitary confinement (OR = 2.52; 95% CI = 1.88, 3.83; and OR = 1.65; 95% CI = 1.23, 2.22; respectively; P < .05). CONCLUSIONS: More consideration is needed of race/ethnicity and age in understanding and addressing the punishment and treatment balance in jails.

Data-Driven Human Rights: Using Dual Loyalty Trainings to Promote the Care of Vulnerable Patients in Jail.

Dual loyalty is an omnipresent feature of correctional health. As part of a human rights quality improvement committee, and utilizing the unique advantage of a fully integrated electronic health record system, we undertook an assessment of dual loyalty in the New York City jail system. The evaluation revealed significant concerns about the extent to which the mental health service is involved in assessments that are part of the punishment process of the security apparatus. As a result, dual loyalty training was developed and delivered to all types of health staff in the jail system via anonymous survey. Six clinical scenarios were presented in this training and staff members were asked to indicate whether they had encountered similar circumstances and how they would respond. Staff responses to the survey raised concerns about the frequency with which they are pressured or asked to put aside their primary goal of patient care for the interests of the security mission. The online training and follow-up small group sessions have revealed widespread support for more training on dual loyalty.