Exposure of Laboratory Workers to Francisella tularensis despite a Bioterrorism Procedure

Abstract

A rapidly fatal case of pulmonary tularemia in a 43-year-old man who was transferred to a tertiary care facility is presented. The microbiology laboratory and autopsy services were not notified of the clinical suspicion of tularemia by the service caring for the patient. Despite having a laboratory bioterrorism procedure in place and adhering to established laboratory protocol, 12 microbiology laboratory employees were exposed to Francisella tularensis and the identification of the organism was delayed due to lack of notification of the laboratory of the clinical suspicion of tularemia. A total of 11 microbiology employees and two persons involved in performing the patient's autopsy received prophylactic doxycycline due to concerns of transmission. None of them developed signs or symptoms of tularemia. One microbiology laboratory employee was pregnant and declined prophylactic antibiotics. As a result of this event, the microbiology laboratory has incorporated flow charts directly into the bench procedures for several highly infectious agents that may be agents of bioterrorism. This should permit more rapid recognition of an isolate for referral to a Level B laboratory for definitive identification and should improve laboratory safety.Francisella tularensis, a fastidious gram-negative coccobacillus, is an uncommonly encountered organism in most clinical microbiology laboratories. Nevertheless, the need for diagnostic laboratories to be familiar with this organism has taken on increased importance due to its possible use as a bioterrorism agent (4,7,8,10,13). F. tularensis has been classified as a Category A critical biological agent because it can be disseminated easily, causes high mortality with the potential for major public health impact, might cause public panic and social disruption, and requires special action for public health preparedness (3). It was reportedly developed as a weapon by both the United States (10) and the Soviet Union (1).Despite the presence in the clinical microbiology laboratory of a written procedure for working with agents of bioterrorism, including F. tularensis, the identification of F. tularensis isolated from a fatal case of pulmonary tularemia was delayed, resulting in the manipulation of the organism at the bench by laboratory workers, many of whom subsequently began taking prophylactic antibiotics. Although tularemia is rare, with approximately 200 cases annually in the United States, in Pike's study of 3,921 cases of laboratory-associated infections, it ranked second in the United States as a cause of laboratory-associated infections, behind only brucellosis, and third worldwide, behind brucellosis and typhoid (15).We report a fatal case of culture-proven tularemia and the associated laboratory investigation prompted upon learning of the cause of the patient's demise. We provide guidelines that will assist other laboratories in suspecting and more safely dealing with infections caused by this organism. Case report.A 43-year-old man with no significant past medical history pr...

Histologic and molecular diagnosis of tularemia: a potential bioterrorism agent endemic to North America

“…28 As FT colonies can be misidentified as similar bacteria (such as Legionella, Y. pestis, Brucella, and Hemophilus influenza) during initial workup, proper precautions for laboratory staff may not be taken. 1,28 The ease with which laboratory workers may contract inhalational tularemia, as well as cutaneous disease acquired from handling specimens and transmitting the organism through small breaks in the skin, has implications for processing specimens from both naturally acquired and potentially deliberate outbreaks. 1,2,3,7,10,14,28 Tularemia has traditionally been divided into six clinical types; due to the great deal of overlap between them, classification has recently been simplified into ulceroglandular or typhoidal/septic types.…”

“…1,28 The ease with which laboratory workers may contract inhalational tularemia, as well as cutaneous disease acquired from handling specimens and transmitting the organism through small breaks in the skin, has implications for processing specimens from both naturally acquired and potentially deliberate outbreaks. 1,2,3,7,10,14,28 Tularemia has traditionally been divided into six clinical types; due to the great deal of overlap between them, classification has recently been simplified into ulceroglandular or typhoidal/septic types. 1,29,30 Regardless of clinical type, most cases have some degree of pulmonary involvement, and over 10% go on to develop ARDS.…”

“…3 It has recently been classified as a Category A agent of potential bioterrorism. 4,12,13,28,38 Due to its virulence and relatively short incubation period, a deliberately caused outbreak of tularemia could conceivably affect a large population within less than a week. 1,4,13 Factors adding to the concern include its widespread presence in nature within a myriad of hosts, in addition to the serious risks posed to laboratory personnel.…”

Increase in Human Cases of Tularemia — Colorado, Nebraska, South Dakota, and Wyoming, January–September 2015

“…Due to the extremely low infectious dose, tularaemia has been one of the most commonly reported laboratory-associated bacterial infections (Pike, 1976; Centers for Disease Control and Prevention, 2000; Shapiro & Schwartz, 2002). Since in most routine laboratories, cultures from clinical samples are handled at the bench, there is an obvious risk of exposure.…”

Emergence ofFrancisella novicidaBacteremia, Thailand

“…As a preliminary result, our 16S rDNA sequence was closely related to subspecies of F. tularensis, and thus doxycycline prophylaxis for the organism-exposed laboratory personnel could not be avoided. There is high risk for laboratory-acquired tularemia when handling F. tularensis cultures (10).…”