PUBLIC HEALTH IMPACTS:NON-FOODBORNE DISEASESJoanne Bartkus, PhD, D(ABMM), HCLDDirector, Public Health LaboratoryMinnesota Department of Health

“If you don’t know where you are, a map won’t help ...”

~ Watts H. Humphrey

Evolving Role of PHLsSurveillance, reference, and response• Outbreak detection and investigation• Rare and emerging diseases• Emergency preparedness and response• Reference and confirmatory testing,

subtyping, AST• Communications and training• Translational/Applied research

Routine diagnostic testing for pathogens of public health concern

Non-culture Tests• Many to choose

from for the same pathogen

• Variable levels of sensitivity and specificity

• Variable levels of test complexity

• Testing done in a variety of settings

Public Health Impact and ResponseDepends on:

Need for pathogen characterization beyond primary diagnosis

Performance characteristics of the CIDT (sensitivity, specificity, PPV, etc.)

Consequence of false-negative/false-positive results

Characteristics of pathogen (mutability, cultivability)

As yet unknown pathogens, antimicrobial susceptibility mechanisms, virulence factors

Need for archival strains for future research, development, method validation

Gonorrhea Testing• NAAT testing almost

universal• Need cultures for AST• GC DNA present for a

month post treatment

• GISP• Sentinel sites perform

AST on cultures from urethral swabs

• Emerging issues• NAAT being approved for

many sample types, little incentive to continue urethral swabs

Legionella Testing• Urine antigen

detection is most common test performed

• Investigations rely on both clinical and environmental isolates for interpretation

• Recommendation is to perform culture in addition to urine antigen

Test Sensitivity (%) Specificity (%) Culture 80 100Urine antigen 70 100Paired serology*

70-80 >90

Direct fluorescent antibody stain

25-75% 95

* Note: A single antibody titer of any level is not diagnostic of legionellosis.

Legionellosis in a Prisoner - Iowa• Male, imprisoned for 8 mo. • hospitalized with

community acquired pneumonia

• Urinary antigen test positive

• Culture not performed

Environmental Investigation• Prison guards felt they

were at risk• Investigation initiated

even though no patient culture available for comparison

• The SPHL microbiologist and medical officer cultured...

Nothing grew....• But, no matter, without the clinical isolate nothing could

have been concluded anyway• No additional cases at the prison• Illustrates the difficulty in withstanding the “political”

pressure to conduct a time-consuming and expensive environmental investigation

Bordetella pertussis

Bordetella pertussis diagnosed in HCW in 396-bed hospital

• 1,000 employees screened, ill employees furloughed• Prophylactic antibiotics to 1,300 contacts • Vaccinated 4,500 people (72% of staff) in a three-day period

134 suspected cases, 98 considered positive

Cultures at SPHL all negative

Confirmatory testing at CDC negative

Hospital lab used a very sensitive single-target PCR test prone to contamination

Many other examples...

Responding to the Challenges

Require submission of isolates/clinical materials to enable confirmatory and supplemental testing for pathogens of public health importance

Percent of Submitted Specimens from Sporadic Cryptosporidium Cases Reported to MDH

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Requirement for submission

Responding to the Challenges

Enhanced surveillance programs to monitor pathogens of public health importance

CDC’s Emerging Infections Program Network

Active Bacterial Core surveillance (ABCs)

CDC, state health departments, and universities

Active laboratory- and population-based surveillance system for invasive bacterial pathogens of public health importance

For each case of invasive disease in the surveillance population

• case report with basic demographic information• bacterial isolates sent to CDC and other reference laboratories for

additional laboratory evaluation.

ABCs in Minnesota

Active surveillance with 118 labs serving 150 hospitals

From 2006-2010: 6,730 cases of invasive disease due to core ABCs pathogens and 1,052 due to MRSA

MDH tested and shipped 7,016 case isolates to CDC

• 6,156 core ABCs and 860 MRSA

Proportions of case-isolates submitted NM 100%, HI 91%, GBS 88%, GAS 91%, and SP 94%.

Develop and implement methods for AST, subtyping, etc. that do not require culture

Responding to the Challenges

Molecular Capabilities of State and Local PHLs – APHL Survey

Ongoing ChallengesDecreased

Funding

Evolving Technology

Workforce Development

Data Privacy

Informatics and

Bioinformatics

Health Reform

Edward Monkton