Direct costs associated with a nosocomial outbreak of Salmonella infection: An ounce of prevention is worth a pound of cure

PRACTICE

FORUM

Direct costs associated with a nosocomial outbreak of Salmonella infection: An ounce of prevention worth a pound of cure

.

N. M. Spearing, RN, BSN” A. Jensen, RN” B. J. McCall, MB, BS, MPH, FAFPHMb A. S. Neil& RN, BAppSc, MNb J. G. McCormack, MD, FRCP, FRACP” Coopers Plains and South Brisbane, Queensland,

is

Australia

Buckground: Nosocomial outbreaks of Salmonella infections in Australia are an infrequent but significant source of morbidity and mortality. Such an outbreak results in direct, measurable expenses for acute care management, as well as numerous indirect (and less quantifiable) costs to those affected, the hospital, and the wider community. This article describes the significant direct costs incurred as a result of a nosocomial outbreak of Sultnonella infection involving patients and staff. Method: Information on costs incurred by the hospital was gathered from a number of sources. The data were grouped into 4 sections (medical costs, investigative costs, lost productivity costs, and miscellaneous) with use of an existing tool for calculating the economic impact of foodborne illness. Results: The outbreak cost the hospital more than AU $120,000. (US $95,000). This amount is independent of more substantial indirect costs. Concksion: Salmonella infections are preventable. Measures to aid the prevention of costly outbreaks of nosocomial salmonellosis, although available, require an investment of both time and money. We suggest that dedication of limited resources toward such preventive strategies as education is a practical and cost-effective option for health care facilities. (AJIC Am J Infect Control 2000;28:54-7)

INTRODUCTION In December 1996,52 people were affected by an outbreak of Salmonella typhimurium at a 600-bed tertiary care complex in Brisbane, Australia. Initially, the outbreak was thought to be localized to the maternity ward, but it became evident that patients in other areas of the hospital, as well as hospital staff, also were affected. The cases included 17 patients, 3 neonates, and 5 spouses of maternity patients, as well as 27 staff (including 4 food handlers). One elderly patient died. Epidemiologic and microbiological investigations confirmed that sandwiches prepared in the hospital kitchen and consumed From Mater Hospital, South Public Health Unit, Coopers

Brisbane.” Plains.b

and

Brisbane

Southside

Reprint requests: Natalie M. Spearing, RN, BSN. CNC Infection Control, University of Queensland, Department of Medicine, Mater Hospital, Raymond Terrace, South Brisbane, Qld 4101 Australia. Copyright Infection

0 2000 by the Association Control and Epidemiology, Inc.

0196-6553/2000/$12.00

54

+ 0

17/49/90920

for

Professionals

in

during a 4-day period were the vehicle of transmission in this outbreak. Although the source of contamination was never found, food storage temperatures and cleaning of food preparation equipment in the hospital kitchen were identified as possible risk factors. This study reviews the direct costs incurred by the hospital as a result of the outbreak. Included are medical costs associated with the hospitalization and treatment of affected persons, the cost of the outbreak investigation, the cost of lost productivity resulting from staff illness, and miscellaneous costs. Direct costs incurred by other components of the health sector, including public health services and the private health care system, were not included in this study. Indirect costs to affected individuals and their families, the health care system, and the community were also generated. Human suffering, loss of life, and lost opportunity and productivity, however significant, are difficult to quantify. ‘J In the interests of establishing a valid minimum estimate of the cost of this outbreak, this article concentrates on the direct costs to the hospital.

AJIC Volume 28. Number

Table

Spearing et al 55

1

1. Direct costs borne

by the hospital

during

the acute phase

of a nosocomial

salmonella

Item

Cost

Direct medical costs Medical costs (includes cost of hospitalization of patients and staff, medication, Cost of follow-up visits to general practitioners Additional medication costs (patients and staff) Subtotal Investigative costs Costs of staff screening plus laboratory staff wages (regular hours plus overtime) Cost of work hours (regular hours plus overtime) dedicated to the investigation (infection control team, occupational health nurse) Phage typing Private laboratory testing Swabs Pathologic specimen containers Pathology requisition slips Subtotal Lost productivity costs Cost of staff work hours lost throuoh illness (includes cost of replacement staff) Worker’s compensation Subtotal Miscellaneous costs External catering Photocopying, postage, and phone calls Subtotal Total cost borne by the hospital ‘Exchange

outbreak

rate on December

15. 1996: AU $1.00

visits

by specialists)

AU S

cost

us s

66,290

708 115 67,113

53,019

19,602 10,887 6000 400 71 50 21 37,031

29,254

13,736 1532 15.268

12,062

500 250 750 120,162

593 94,928

= US $0.79.

METHODS The costs measured in this study include all expenses sustained by the hospital during the acute phase of the outbreak. A number of articles documenting the cost of outbreaks exist; however, no standard measurement tool was used in these studies.‘.3-6 For the purposes of this article, a format for calculating direct costs was obtained from the Economic Evaluation of a Foodborne Disease Outbreak (Form J).* Medical costs, investigative costs (including pathology expenses), the cost of lost productivity in the workplace as a result of staff illness, and miscellaneous costs associated with administrative tasks were calculated. Medical costs were obtained through a review of medical records data. Hospitalization expenses of affected patients and staff included medical and nursing services, medication, treatments, and visits by specialists. Costs for follow-up visits to medical practitioners and prescribed medications were also determined. The task of investigating and managing the outbreak involved the infection control team (infectious diseases physician and 2 infection control practitioners) and the occupational health nurse and Pathology Department staff. Time (approximately 700 hours) dedicated throughout a 4-week period was multiplied by the respective hourly wage rates.

The costs of pathologic testing related to the investigation, pathology materials, and external phage typing were obtained. The expense of acute care pathologic testing was based on Medicare costs of relevant tests. Costs associated with lost productivity were a consequence of staff becoming ill after consuming contaminated sandwiches at hospital functions. Those absent from work because of illness or released from work as a result of asymptomatic carriage were compensated. Costs were based on the number of hours lost by each staff member, multiplied by wage figures obtained from salary scales. Medical expenses incurred by staff, including use of the worker’s compensation scheme, were calculated. Miscellaneous expenses involved administrative expenses and the cost of external catering during the outbreak. RESULTS The conservative estimate of the direct cost to the hospital of this large nosocomial outbreak of salmonellosis is approximately AU $120,000 (US $95,000). Table 1 provides a cost breakdown. Costs for hospitalization of the affected patients and staff comprised the greatest direct expense to the hospital. Prolonged hospitalization was required for maternity patients who, together with their partners, consumed contaminated sandwiches. One neonate was

AJIC

56

Spearing et al

subsequently readmitted because of second,ary transmission from an infected mother. Four patients in the adult hospital also became ill. Costs associated with hospitalization included private and public hospital fees, as well as fees incurred by visiting specialists (obstetricians, pediatrician, and infectious diseases physician). Additionally, 10 nonhospitalized patients required antibiotic treatment. The costs of follow-up testing, medications, and visits to general practitioners were borne by the hospital. A significant amount of time was dedicated to investigating and managing the outbreak. With assistance from the Brisbane Southside Public Health Unit, information was gathered from cases and control patients in the maternity ward to identify a possible vehicle of transmission. All raw and uncooked foods were removed from the menu on the first day of investigation, halting the spread of infection. Kitchen facilities and food production and distribution practices were reviewed. Clinical and microbiologic surveillance was expanded; new cases were identified and investigated during a period of 2 weeks. Obtaining and communicating updated information, both within the hospital and externally, during the acute phase was an important component in managing the outbreak. Finally, follow-up of affected patients and staff proved a lengthy and time-consuming process. Laboratory expenses were based primarily on the cost of screening staff and patients, as well as follow-up stool cultures performed in the identified cases. Positive fecal specimens, as well as food samples, were sent for phage typing. The results demonstrated a link between the cases and a sample of curried egg mixture. One laboratory staff member was dedicated entirely to processing the microbiologic specimens related to the outbreak. Nursing staff working on the affected maternity wards submitted rectal swabs; none produced a positive result. Rectal swabs of kitchen staff identified 4 food handlers positive for S. typhimurium infection. Serial stool specimens were collected from these employees. Two were asymptomatic carriers subsequently treated for carriage and followed up until 3 separate, negative fecal specimens demonstrated microbiologic clearance of the organism. Two food handlers had gastrointestinal symptoms and remained off work until they had no more symptoms. There was no apparent link between Salmonella-positive kitchen staff and the production of contaminated sandwiches. Lost productivity costs arose when staff members became ill after consumption of contaminated sandwiches at hospital functions. Medical, nursing, allied health, food services, and engineering staff were involved. Two staff members were hospitalized. All employees who reported gastrointestinal symptoms during the specified time submitted fecal samples. Staff

February

2000

(other than kitchen staff) were permitted to return to work once gastrointestinal symptoms had ceased. Infected kitchen staff were required to submit 3 consecutive, negative fecal specimens collected at least 24 hours apart. Leave with pay and coverage of related expenses were provided. Miscellaneous costs arising from external catering during the acute phase of the outbreak and administrative costs associated with mailing out information to the affected people and their general practitioners were minimal compared with other costs. DISCUSSION In recent decades, a large number of outbreaks of salmonellosis have been documented in the hospital environment.‘,s,7-9 These outbreaks are of major concern because of the susceptibility of hospital patients to salmonella infection and its sequelae.‘O One study concluded that the case-fatality rate in health care institutions is 70 times higher than in other settings and that measures such as health education are important in preventing the disease.j As salmonellosis is a preventable disease, evaluating the cost of an outbreak illustrates the economic benefit to be gained from instituting preventive measures.j A number of data collection tools and methods for costing salmonella outbreaks are available.‘~6~‘0~” Establishing the cost per case of salmonella is one method. This outbreak resulted in a cost per case of AU $2310 (US $1824). Another study (involving a similar hospital scenario and focusing on direct costs) calculated a cost of AU $3251 (US $2568) per case.” Other studies have shown a range between AU $2 198 (US $1736) and AU $2460 (US $1943) per case; however, these have included both direct and indirect costs and involved a variety of circumstances. Avoiding the substantial cost associated with salmonella outbreaks is desirable and feasible. Studies suggest that primary prevention, rather than the introduction of routine fecal screening of food handlers,’ is beneficial in reducing the risk of this disease.‘,7,12 Before the outbreak, in-house food hygiene training was conducted; however, attendance was not monitored or enforced. A risk management strategy should ensure education of institutional staff in the essential aspects of food hygiene and handling. The cost of training all food handlers (50 people) to food industry standards at this hospital was AU $3250 (US $2567). Additionally, 2 supervisors were trained in the implementation of the Hazard Analysis and Critical Control Point food quality system at a cost of AU $2000 (US $1580). Cost-benefit analysis has demonstrated that such prevention strategies as staff education are worthwhile in preventing outbreaks of food-borne illness.lz In this case, the expense of training

AJIC Volume

28. Number

Spearing

1

food services staff to industry standards was minimal compared with the direct cost of the outbreak. This study demonstrates the substantial expense incurred by one hospital as a result of an outbreak of preventable disease. The implementation of comparatively inexpensive primary prevention strategies can reduce the risks to physical and economic well-being. We suggest that the investment of minimal resources to institute basic preventive measures presents an opportunity for health care institutions to significantly reduce the total expense to the hospital, health care system, and society.

monella food poisoning due to inadequate deep fat frying. Epidemiol Infect 1996;116:155-60. Yule BF, Macleod AF, Sharp JCM, et al. Costing of a hospital-based outbreak of poultry-borne salmonellosis. Epidemiol Infect 1988;100:35-42. Djuretic T, Ryan MJ. Wall PG. The cost of inpatient care for acute infectious intestinal disease in England from 1991 to 1994. Commun Dis Rep 1996;6(5):R78-80. Khuri-Bolos N. Khalaf M, Shehabi A, et al. Food handler associated salmonella outbreak in a university hospital despite routine surveillance cultures of kitchen employees. Infect Control Hosp Epidemiol 1994;15:31 l-4. Joseph C, Palmer S. Outbreaks of salmonella infection in hospitals in England and Wales, 1978-87. BMJ 1989;298:1161-4. Telzak E, Budnick L. Greenberg M, et al. A nosocomial outbreak of Salmonella enreriridis infection due to the consumption of raw eggs. N Engl J Med 1990;323:394-7. Roberts J, Socket P. The socio-economic impact of human salmonella enteritidis infection. Int J Food Microbial 1994;21:117-29. Dryden MS, Keyworth N. Gabb R, et al. Asymptomatic foodhandlers as the source of nosocomial salmonellosis. J Hosp Infect 1994:28: 195-208. Roberts J. Socket P, Gill 0. Economic impact of a nationwide outbreak of salmonellosis: cost benefit of early intervention. BMJ 1989;298:1227-30.

5.

6.

7.

8. 9.

References 1. Voss S. Costs to affected individuals following an outbreak of food poisoning: a pilot study. Public Health 1993;107:337-41. 2. International Association of Milk, Food and Environmental Sanitarians Inc. Procedures to investigate foodbome illness. 4th ed. Des Moines (IA): The Association: 1988. 3. Dalton CB. Haddix A, Hoffman RE. et al. The cost of a food-borne outbreak of hepatitis A in Denver Cola. Arch Intern Medicine 1996;156:1013-6. 4. Evans M. Hutchings P, Ribeiro C, et al. A hospital outbreak of sal-

Expanding the role control professional use of antibiotics

et al 57

10 11

12.

of the infection in the cost-effective

Art5zou Minooee, BS Leland S. Rickman, MD San Diego, California

There

is a growing

University

ed and found tion control drug

monitoring. of colonization

Medical

Mechanisms

(ICP)

stop orders,

tion of the appropriate treatment

that health care expenses

San Diego

to be effective. professional

of use. automatic target

demand

of California,

while

use of antibiotics rather

designed

control

strategies antibiotic

such goals control

management, professional,

as well

use reviews, as other

individual

or when appropriate

and inappropriate

diminishing

quality

educational

efforts,

utilization formulary

of the antimicrobial

cases in which testing

antibiotics

reducing

of care involve

such as antimicrobial

members

microbiologic

use of antibiotics

drug usage and subsequently

without

stratagems

drug

in part by identifying

than infection

and that excessive

aimed at controlling

to achieve

implementing

computer-assisted

The infection

be contained

Center,

might

practice,

the role of the infec-

antibiotic

order

restricted

drug policies,

team, contributes

be used inappropriately,

has not been carried

out. (AJIC

At the

costs have been implement-

expanding

teams,

utilization

be eliminated.

sheets,

audits and

to the promosuch as for the

Am J Infect

Control

2000;28:57-65)

Antibiotics account for a significant proportion of drug expenditures in today’s inpatient medical practice. From the Department Diseases, University Reprint UCSD 92103. Copyright Infection

requests: Medical

Leland S. Rickman, MD, Center-8951, 200 W Arbor

0 2000 Control and

0196-6553/2000/$12.00

of Biology and the Department of California, San Diego.

by the Association Epidemiology, Inc. + 0

17/49/103665

of Infectious

Epidemiology Unit, Dr, San Diego, CA for

Professionals

in

Most of the information regarding the evaluation of antibiotic use comes from studies performed in hospital settings, where it has been reported that antibiotics have been used inappropriately more than 50% of the time.‘” The excessive and inappropriate use of antimicrobial agents raises much concern because of high costs, adverse reactions to the drugs, and the burden of resistant organisms.“ Given the importance of current and future cost containment, the role of the infection control professional (ICP) becomes increasingly important. For example, one of the principal responsibilities