(Nutritionally Variant Streptococcus Serotype II) Group Antigen
Introduction Epidemiological & Investigational Issues ... · Shigella sonnei is the predominant...
1
A. Singh 1 , P. Biedrzycki 2 , M. Khubbar 1 , D. Griswold 1 , J. Lokken 1 , V. Kalve 1 , B. Krause 1 , A. Hagy 2 , S. Gradus 1 . City of Milwaukee Health Dept. 1 Division of Public Health Laboratories and 2 Division of Disease Control and Environmental Health, Milwaukee,WI Tom Barrett, Mayor Bevan K. Baker, Commissioner of Health www.milwaukee.gov/health MHD Graphics 4/09 Child care centers >100 Family clusters >250 Most cases “high risk” • Childcare-related • Food Handler • School-related • Healthcare Worker Average case takes more than a month to close (from diagnosis to TOC). • May require multiple trips to home or other location for interviews and contact identification • Follow-up of symptomatic contacts • Time to track people Interview case: disease questionnaire; assessment; teach case • Symptomatic contacts: refer to primary care provider • High risk cases require test of cure (most cases) • Two negative specimens before returning to work • Collaborate with physician Childcare facilities • On-site inspection • Notification letter to contacts • Identification of other symptomatic individuals • Education with provider on hygiene measures • Issues notice of exclusion of sick individuals Abstract Objective: To describe the metrics, challenges, successes and lessons learned by a local public health laboratory during a prolonged surge of shigellosis within a community setting. Study Design: A prolonged surge of 5 to 15-fold increase in shigella specimens per month from February 2007, peaking in June and July and not returning to baseline until May 2008, resulted in over 500 cases and over 400 laboratory isolates. Intense community messaging to media, laboratories, physicians, child care facilities and recreational water operators likely enhanced surge. By early summer laboratory and investigational workloads were beyond capacity resulting in delayed investigations, laboratory turn-around time, and significant stress among staff. Laboratory strategies to cope with the beyond-capacity surge included invoking a pre-arranged agreement with the state public health laboratory for assistance, additional cross training of staff, abbreviating work- up of stool cultures, limiting PFGE testing and allowing interns to assist in some areas. Results: The laboratory played a key role in detecting resistant strains and outbreak patterns. A predominate PFGE pattern (81% of 393) with a rhamnose negative marker (99%) consisted of two minor subsets. Seven additional patterns among 39 (12%) isolates were detected. Strains were resistant to ampicillin (75%), SXT (66%) or both (54%) for all strains and outbreak strains were more resisitant, 87% and 83% respectively. Surge interventions to support these activities provided mixed results. Conclusions: Surge planning is critical and a variety of creative interventions are nec- essary to address such public health events that might exceed the threshold of expected capacity. Scope • 15 month-long “local” epidemic: March 2007 through May 2008 • 607 cases • 461 isolates shigella • Shigella cases per month • Pre-outbreak average = 10 cases/month • Outbreak average = 32 cases per month • Antimicrobial resistant outbreak strain • Ampicillin = 87% • SXT = 83% • TOC = Test of Cure samples sent to state lab • Baseline average/mo. = 10 • Total cases = 607 • Outbreak average cases/mo. = 32 • Lab confirmed cases = 461 • Max. = 75, June 2007 Introduction Shigella sonnei is the predominant serotype in U.S. community outbreaks of shigellosis. S. sonnei, a highly infectious agent, is transmitted by the fecal-oral route, spreads quickly and persists in daycare and preschool settings. Intervention of community out- breaks of shigellosis becomes a challenging task for public health management and demands considerable time, effort, and expense. From March 2007 through March 2008 the Milwaukee Health De- partment (MHD) detected an increase in Shigella sonnei due to outbreaks in multiple child care facilities and family clusters. Intense community messaging to media, laboratories, physicians, child care facilities and recreational water operators may have en- hanced awareness of the ongoing outbreak resulting in an increase in laboratory diagnosis and reporting of the disease. The laboratory, although with surge workload well beyond its normal capacity, tracked the disease using markers and tools such as antibiotic resistance, rhamnose utilization and pulsed-field gel electrophoresis (PFGE). Outbreak related isolates were resistant to sulfamethoxasole-trimethorpim (SXT) (83%%) and ampicillin (amp) (87%). Majority of these isolates lacked the capacity to fer- ment rhamnose (99%). PFGE subtyping resulted in two typical pat- terns differing by a band associated with this outbreak. The large number and continued transmission of cases within the community placed an unusually heavy workload on both the labo- ratory staff and the case investigators. Changes and modifications in work flow were introduced to keep pace with the unexpected and prolonged surge. Description / Timeline • March ’07, increase in cases noted • June-July ‘07, peak • MD notifications of multi-drug resistant Shigella • July ‘07, press release • Nov. - Dec. ’07, heavy case load continues (2nd peak) • May ’08, baseline returns to pre-March ’07 levels • foci of outbreaks: child care centers(>100) & family clusters (>250) • many high risk patients: • childcare • healthcare • food establishments • schools Lab Impact • 5X-15X increase in monthly specimens from 2/07-5/08 • PFGE and antimicrobial susceptibility testing (n = 313) • lab operational impacts: • turn-around times • backlogs • complaints • MOU with state lab activated • 349 test of cure (TOC) cultures sent to state lab over 12 months • Backlog of O&Ps sent to state lab • increased messaging to local clinical labs through local eLab-network • Work-time units (WTUs) – a work load unit for minutes of analytical work for i) enteric culture, ii) Shigella identification, iii) PFGE and iv) susceptibility test Epidemiological & Investigational Issues & Strategies Schools • On-site inspection if young children onsite • Notification letter to contact • Identification of other symptomatic individuals • Education with provider on hygiene measures • Issue notice of exclusion of sick individuals Food handler • Referral made to food inspectors • Issue notice of exclusion of sick individuals Healthcare worker • Assess (via phone) if other illness within the facility • Issue notice of exclusion of sick individuals Other strategies • Mass messaging via mail and telephone to licensed child care facilities • Messaging to physicians: increase in cases and antibiotic resistance • Press release to inform community about Shigella and prevention techniques • Increase recreational water surveillance to assure adequate chlorination Summary and Conclusions 1. Naturally occurring outbreaks like shigella that are of long duration represent a sustainability issue for lab, epi and environmental health that generally go well beyond typical emergency preparedness planning. This represents continued vulnerability for LPHAs in not being able to rapidly quench CD outbreaks and face relentless surging of assets (personnel, supplies, equipment) at the expense of other issues. 2. LPHA response fatigue is always a threat during these types of events. Models for engaging other stakeholders in early response and mitigation is essential (private healthcare, daycares, schools, etc.) 3. Rapid ID by lab to characterize strain and antibiotic sensitivity is critical and part of the new Health Security Intelligence models that are being advocated by the federal government. This information is critical for "epidemiologic situational awareness" as well and plays a prominent role in intervention decisions by epi and others. Historical recognition: Historical recognition: Milwaukee has periodic extensive shigellosis outbreaks, often with winter peaks. 2 “In the developing countries, a combination of contact and waterborne spread can contribute to a prolonged, smoldering epidemic that lasts for months rather than weeks, until the population of susceptibles is exhausted.” 3 1 MMWR. January 30, 2004. 53(03);60-63 Day care related outbreaks of rhamnose negative Shigella sonnei. Six States, June 2001--March 2003. 2 Gradus, M.S. and H. D. Nichamin. 1989. Shigellosis winter trends in Milwaukee. Wisc. Med. Journal. April. Pp. 17-18. 3 Keusch & Bennish, Shigellosis,Chpt 32 in Bact. Inft. Humans. 1998. 4. Shigella may not result in high mortality but the economic and social implications of long-term outbreaks are significant (lost work-time by parents, closures of daycares, cost for environmental disinfection, etc.) 5. The shigella outbreak is an opportunity to hone the lab-epi interface and skill sets to create a "response memory" by department staff and should be mined for lessons learned by lab, epi and administration. 6. Milwaukee and other cities (1,2) historically have long term shigellosis outbreaks and can anticipate and plan for future such outbreaks, often with winter peaks. Lab confirmed outbreak-related cases of Shigella sonnei: 393 PFGE performed: 313 PFGE Confirmed Outbreak Cases Xbal patterns: n=254 • n=178: J16X01.0283 • n=76: J16X01.0199 • 97.57% similarity Both PFGE patterns were not seen in 2006 Other significant PFGE Xbal patterns seen: • J16X01.1467 (17 cases) • J16X01.0917 (8 cases) • J16X01.0674 (7 cases) Antibiogram Outbreak strains were mostly “antibiotic resistant” Rhamnose Utilization Outbreak strains were “rhamnose negative” Pulse Field Gel Electrophoresis (PFGE) Activity Shigella sonnei Strain Characterization Laboratory Surge Implications of 15 Month Long Shigellosis Outbreak Critical Control Points Exceeded (Lab beyond capacity) The Good (actions taken to address surge) The Bad (challenges, problems encountered, lessons learned) The Unpredictable • Specimens: overwhelmed system • Supplies: Shortages • Staffing: vacations, vacancies, retirements • Invoked surge agreement with state lab • TOCs (n=349) to state lab: 6/07–5/08 • O&P backlog to state • Abbreviated workup of Shigella • Cross-trained staff • Limited PFGE testing • Messaging to local clinical labs • Intern (undergraduate) created histori- cal susceptibility database • Temporary elimination of non-essential tests • Hire temporary staff • Delay in limiting PFGE testing • Delay in cross-training • Backlog of O&Ps • Supply shortages (transport media) • Utility of enrichment broth • Delayed turnaround time • Complaints of care gives • Reporting to epi staff • Backlog in epidemiologic follow-up: • Nurse case charting hindered • Timeliness of surveillance data • Increased overall response time • Exam of PFGE patterns • Historical memory lost of similar community outbreaks • Length and intensity of outbreak • Staff burnout • Resistant shigella • Rhamnose marker • Outbreak strain similarities with previous report (i) Shigella sonnei Cases 2007–2008 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Total number of cases Lab confirmed New Cases TOC Number of Cases Month 100 80 60 40 20 0 Work-Time Units (WTUs) for Detection & Testing of Shigella sonnei 600 500 400 300 200 100 0 WTUs (x100) Year 2001 2002 2003 2004 2005 2006 2007 2008 Number of Reported Cases 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 Yearly Quarters 1 2 3 41 2 3 41 2 3 41 2 3 41 2 3 41 2 3 41 2 3 41 2 3 41 2 3 41 2 3 41 2 3 4 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 Shigella Reported Cases - Milwaukee 1978-1988 Relationship Between Rhamnose Utilization and Outbreak Cases 0 50 100 150 200 250 300 Outbreak Cases Non-outbreak Cases Rhamnose Utilization Positive Negative Number of Cases PFGE Strain Rhamnose Not Utilized “n” – Value Outbreak 99% 259 Non-outbreak 35% 54 <15% referred Shigella sonnei to CDC 1974-2002 were rhamnose negative1 Relationship Between Antibiotic Resistance and Outbreak Cases Number of Cases % Resistant to SXT % Resistant to AMP % Resistance Outbreak Cases Non-outbreak cases 100% 80% 60% 40% 20% 0% PFGE Strain Resistant or Intermediate “n” – Value SXT Amp Outbreak 83% 87% 259 Non-outbreak 20% 44% 54
Transcript of Introduction Epidemiological & Investigational Issues ... · Shigella sonnei is the predominant...
A. Singh1, P. Biedrzycki2, M. Khubbar1, D. Griswold1, J. Lokken1, V. Kalve1, B. Krause1, A. Hagy2, S. Gradus1. City of Milwaukee Health Dept. 1Division of Public Health Laboratories and 2Division of Disease Control and Environmental Health, Milwaukee,WI
Tom Barrett, MayorBevan K. Baker,Commissioner of Health
www.milwaukee.gov/health
MHD Graphics 4/09
Child care centers >100 Family clusters >250
Most cases “high risk”• Childcare-related • Food Handler• School-related • Healthcare Worker
Average case takes more than a month to close (from diagnosis to TOC).• May require multiple trips to home or other location for interviews and
contact identification• Follow-up of symptomatic contacts• Time to track people
Interview case: disease questionnaire; assessment; teach case• Symptomatic contacts: refer to primary care provider• High risk cases require test of cure (most cases)• Two negative specimens before returning to work• Collaborate with physician
Childcare facilities• On-site inspection• Notification letter to contacts• Identification of other symptomatic individuals• Education with provider on hygiene measures• Issues notice of exclusion of sick individuals
AbstractObjective: To describe the metrics, challenges, successes and lessons learned by a
local public health laboratory during a prolonged surge of shigellosis within a
community setting.
Study Design: A prolonged surge of 5 to 15-fold increase in shigella specimens per
month from February 2007, peaking in June and July and not returning to
baseline until May 2008, resulted in over 500 cases and over 400 laboratory
isolates. Intense community messaging to media, laboratories, physicians,
child care facilities and recreational water operators likely enhanced surge. By
early summer laboratory and investigational workloads were beyond capacity
resulting in delayed investigations, laboratory turn-around time, and significant
stress among staff. Laboratory strategies to cope with the beyond-capacity
surge included invoking a pre-arranged agreement with the state public health
laboratory for assistance, additional cross training of staff, abbreviating work-
up of stool cultures, limiting PFGE testing and allowing interns to assist in
some areas.
Results: The laboratory played a key role in detecting resistant strains and outbreak
patterns. A predominate PFGE pattern (81% of 393) with a rhamnose negative
marker (99%) consisted of two minor subsets. Seven additional patterns
among 39 (12%) isolates were detected. Strains were resistant to ampicillin
(75%), SXT (66%) or both (54%) for all strains and outbreak strains were
more resisitant, 87% and 83% respectively. Surge interventions to support
these activities provided mixed results.
Conclusions: Surge planning is critical and a variety of creative interventions are nec-
essary to address such public health events that might exceed the threshold of
expected capacity.
Scope• 15 month-long “local” epidemic: March 2007
through May 2008
• 607 cases
• 461 isolates shigella
• Shigella cases per month• Pre-outbreak average = 10 cases/month• Outbreak average = 32 cases per month
• Antimicrobial resistant outbreak strain• Ampicillin = 87%• SXT = 83%
• TOC = Test of Cure samples sent to state lab • Baseline average/mo. = 10• Total cases = 607 • Outbreak average cases/mo. = 32• Lab confirmed cases = 461 • Max. = 75, June 2007
IntroductionShigella sonnei is the predominant serotype in U.S. community
outbreaks of shigellosis. S. sonnei, a highly infectious agent, is
transmitted by the fecal-oral route, spreads quickly and persists in
daycare and preschool settings. Intervention of community out-
breaks of shigellosis becomes a challenging task for public health
management and demands considerable time, effort, and expense.
From March 2007 through March 2008 the Milwaukee Health De-
partment (MHD) detected an increase in Shigella sonnei due to
outbreaks in multiple child care facilities and family clusters.
Intense community messaging to media, laboratories, physicians,
child care facilities and recreational water operators may have en-
hanced awareness of the ongoing outbreak resulting in an increase
in laboratory diagnosis and reporting of the disease.
The laboratory, although with surge workload well beyond its
normal capacity, tracked the disease using markers and tools such
as antibiotic resistance, rhamnose utilization and pulsed-field gel
electrophoresis (PFGE). Outbreak related isolates were resistant to
sulfamethoxasole-trimethorpim (SXT) (83%%) and ampicillin
(amp) (87%). Majority of these isolates lacked the capacity to fer-
ment rhamnose (99%). PFGE subtyping resulted in two typical pat-
terns differing by a band associated with this outbreak.
The large number and continued transmission of cases within the
community placed an unusually heavy workload on both the labo-
ratory staff and the case investigators. Changes and modifications
in work flow were introduced to keep pace with the unexpected
and prolonged surge.
Description / Timeline• March ’07, increase in cases noted
• June-July ‘07, peak
• MD notifications of multi-drug resistant Shigella
• July ‘07, press release
• Nov. - Dec. ’07, heavy case load continues(2nd peak)
• May ’08, baseline returns to pre-March ’07levels
• foci of outbreaks: child care centers(>100) &family clusters (>250)
• many high risk patients:• childcare• healthcare• food establishments• schools
Lab Impact• 5X-15X increase in monthly specimens from
2/07-5/08
• PFGE and antimicrobial susceptibility testing(n = 313)
• lab operational impacts:• turn-around times• backlogs• complaints
• MOU with state lab activated• 349 test of cure (TOC) cultures sent
to state lab over 12 months• Backlog of O&Ps sent to state lab
• increased messaging to local clinical labsthrough local eLab-network
• Work-time units (WTUs) – a work load unit for minutes of analytical work for i) entericculture, ii) Shigella identification, iii) PFGE and iv) susceptibility test
Epidemiological & Investigational Issues & Strategies
Schools• On-site inspection if young children onsite• Notification letter to contact• Identification of other symptomatic individuals• Education with provider on hygiene measures• Issue notice of exclusion of sick individuals
Food handler• Referral made to food inspectors• Issue notice of exclusion of sick individuals
Healthcare worker• Assess (via phone) if other illness within the facility• Issue notice of exclusion of sick individuals
Other strategies• Mass messaging via mail and telephone to licensed child care facilities• Messaging to physicians: increase in cases and antibiotic resistance• Press release to inform community about Shigella and prevention
techniques• Increase recreational water surveillance to assure adequate chlorination
Summary and Conclusions
1. Naturally occurring outbreaks like shigella that are of long durationrepresent a sustainability issue for lab, epi and environmental healththat generally go well beyond typical emergency preparednessplanning. This represents continued vulnerability for LPHAs in notbeing able to rapidly quench CD outbreaks and face relentlesssurging of assets (personnel, supplies, equipment) at the expense ofother issues.
2. LPHA response fatigue is always a threat during these types ofevents. Models for engaging other stakeholders in early responseand mitigation is essential (private healthcare, daycares, schools,etc.)
3. Rapid ID by lab to characterize strain and antibiotic sensitivity iscritical and part of the new Health Security Intelligence models thatare being advocated by the federal government. This information iscritical for "epidemiologic situational awareness" as well and plays aprominent role in intervention decisions by epi and others.
Historical recognition:Historical recognition: Milwaukee has periodic extensiveshigellosis outbreaks, often with winter peaks.2
“In the developing countries, a combination of contact andwaterborne spread can contribute to a prolonged, smolderingepidemic that lasts for months rather than weeks, until thepopulation of susceptibles is exhausted.”3
1 MMWR. January 30, 2004. 53(03);60-63 Day care related outbreaks of rhamnose negative Shigellasonnei. Six States, June 2001--March 2003.
2 Gradus, M.S. and H. D. Nichamin. 1989. Shigellosis winter trends in Milwaukee. Wisc. Med. Journal.April. Pp. 17-18.
3 Keusch & Bennish, Shigellosis,Chpt 32 in Bact. Inft. Humans. 1998.
4. Shigella may not result in high mortality but the economic andsocial implications of long-term outbreaks are significant (lostwork-time by parents, closures of daycares, cost forenvironmental disinfection, etc.)
5. The shigella outbreak is an opportunity to hone the lab-epiinterface and skill sets to create a "response memory" bydepartment staff and should be mined for lessons learned bylab, epi and administration.
6. Milwaukee and other cities (1,2) historically have long termshigellosis outbreaks and can anticipate and plan for futuresuch outbreaks, often with winter peaks.
Lab confirmed outbreak-related cases of Shigella sonnei: 393
PFGE performed: 313
PFGE Confirmed Outbreak Cases Xbal patterns: n=254• n=178: J16X01.0283• n=76: J16X01.0199• 97.57% similarity
Both PFGE patterns were not seen in 2006
Other significant PFGE Xbal patterns seen:• J16X01.1467 (17 cases)• J16X01.0917 (8 cases)• J16X01.0674 (7 cases)
AntibiogramOutbreak strains were mostly“antibiotic resistant”
Rhamnose UtilizationOutbreak strains were“rhamnose negative”
Pulse Field Gel Electrophoresis(PFGE) Activity
Shigella sonnei Strain Characterization
Laboratory Surge Implications of 15 Month Long Shigellosis OutbreakCritical Control Points Exceeded
(Lab beyond capacity)The Good
(actions taken to address surge)The Bad
(challenges, problems encountered, lessons learned)The Unpredictable
• Specimens: overwhelmed system
• Supplies: Shortages
• Staffing: vacations, vacancies, retirements
• Invoked surge agreement with state lab• TOCs (n=349) to state lab:
6/07–5/08• O&P backlog to state
• Abbreviated workup of Shigella
• Cross-trained staff
• Limited PFGE testing
• Messaging to local clinical labs
• Intern (undergraduate) created histori-cal susceptibility database
• Temporary elimination of non-essentialtests
• Hire temporary staff
• Delay in limiting PFGE testing
• Delay in cross-training
• Backlog of O&Ps
• Supply shortages (transport media)
• Utility of enrichment broth
• Delayed turnaround time• Complaints of care gives• Reporting to epi staff
• Backlog in epidemiologic follow-up:• Nurse case charting hindered• Timeliness of surveillance data• Increased overall response time• Exam of PFGE patterns
• Historical memory lost of similar community outbreaks
• Length and intensity ofoutbreak
• Staff burnout
• Resistant shigella
• Rhamnose marker
• Outbreak strain similaritieswith previous report (i)
Shigella sonnei Cases 2007–2008
Jan
Feb
Mar Apr
May Jun Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar Apr
May
Total number of cases Lab confirmed New Cases TOC
Num
bero
fCas
es
Month
100
80
60
40
20
0
Work-Time Units (WTUs)for Detection & Testing of Shigella sonnei
600500400300200100
0
WTUs(x100)
Year
2001 2002 2003 2004 2005 2006 2007 2008
Num
bero
fRep
orte
dCa
ses
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Yearly Quarters
1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
1501401301201101009080706050403020100
Shigella Reported Cases - Milwaukee 1978-1988
Relationship Between Rhamnose Utilizationand Outbreak Cases
0
50
100
150
200
250
300
Outbreak Cases Non-outbreak Cases
Rhamnose UtilizationPositiveNegative
Num
bero
fCas
es
PFGE Strain Rhamnose Not Utilized “n” – ValueOutbreak 99% 259Non-outbreak 35% 54
<15% referred Shigella sonnei to CDC 1974-2002 were rhamnose negative1
Relationship Between Antibiotic Resistanceand Outbreak Cases
Number of Cases
% Resistant to SXT% Resistant to AMP
%Re
sist
ance
Outbreak Cases Non-outbreak cases
100%
80%
60%
40%
20%
0%
PFGE Strain Resistant or Intermediate “n” – ValueSXT Amp
Outbreak 83% 87% 259Non-outbreak 20% 44% 54
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