First report: Necrotizing fasciitis from a needlestick
Health care worker infected from minor’ injury
The first case of a health care worker developing necrotizing fasciitis due to group A streptococcus contracted from a needlestick injury has been reported.1 While some infectious disease experts maintain that another such event is unlikely, one of the HCW’s treating physicians says the incident carries a grim warning to other health care providers who are occupationally exposed to blood.
The recent report describes the case of a 27-year-old healthy internal medicine resident who was "scratched" on the dorsal aspect of her left fifth metacarpal-phalangeal joint by a needle used to insert a central venous catheter into a hospital patient. The patient had been admitted to the emergency room at Hermann Hospital in Houston with sepsis of unknown cause.
Carin Hagberg, MD, who helped treat the resident, tells Hospital Employee Health that the injury occurred when another health care provider who had removed the used needle from the patient’s vein accidentally "grazed" the resident with it.
Hagberg is one of three physicians from the University of Texas-Houston Medical School (with which the teaching hospital is affiliated) who wrote the report. They state that within 14 hours of the injury, the resident developed erythema, induration, and pain in her hand, followed by chills and fever (101.1 degrees F). She initially was treated with nafcillin, but penicillin G and clindamycin were added when it was discovered that the patient had died 12 hours after admission from group A streptococcus sepsis.
Within the next 48 hours, the resident developed leukocytosis, "followed by leukopenia, a prolonged prothrombin time and partial-thromboplastin time, decreased hemoglobin level and platelet count, hypotension, and progression of the area of induration and erythema toward her elbow and axilla." This led to the diagnosis of necrotizing fasciitis due to group A streptococcus.
Surgery to remove the organism and prevent its spread up the arm revealed necrosis of subcutaneous tissue, fascia, and muscle. The resident was discharged after 17 days of treatment and has recovered, although she was left with some disfigurement of the left arm due to a muscle flap that was used to close the wound defect.
Published reports confirm that prompt diagnosis and early, aggressive antibiotic and surgical interventions are necessary to prevent mortality.2-4 Mortality rates as high as 22%3 and 34%5 have been reported. Necrotizing fasciitis has been called "one of the most serious infections known to humans."4
No other reports of a health care worker acquiring necrotizing fasciitis due to group A strep from a needlestick appear in the medical literature. The only related published report concerns a firefighter who developed cellulitis and a toxic shock-like syndrome after exposure to respiratory tract secretions contaminated with group A strep while performing cardiopulmonary resuscitation.6
The Houston report notes that group A strep is a "well-known cause of necrotizing fasciitis," and that "recent reports have emphasized the increase in aggressive infections due to this organism." Nevertheless, despite this and despite the resident’s apparently minor injury, rapid infection progression, and need for aggressive therapy another event is not likely, says William Trick, MD, an epidemiologist in the hospital infections branch of the U.S. Centers for Disease Control and Prevention.
"Following recommended infection control practices such as not manipulating needles and disposing of them promptly would make this an uncommon occurrence," says Trick, who notes that he is not familiar with the details of this particular injury. "This is the first documented case of patient-to-health care worker transmission over the years, so it is very rare. In addition, now that needleless devices are so much more common, this could remain an uncommon occurrence. The risk is there for people who use needles for any procedure, but overall, the risk is minimized when needleless devices are used."
Percutaneous infection transmission from a scratch is even more unusual. "Typically, the deeper the percutaneous exposure, the more likely there would be an inoculum of the organism," he says.
Because patient-to-HCW transmission has never been documented before, no level of risk can be established. The CDC does not have guidelines on postexposure treatment, but Trick emphasizes the need for exposure reporting so employee health or infection control practitioners can investigate and take appropriate measures promptly.
It wasn’t especially deep’
It is not known whether the resident immediately reported her exposure, but John H. Rex, MD, an infectious disease specialist who co-wrote the report, characterizes the injury as "trivial."
"It was not an injury that anybody would have been very excited about," he says. "It wasn’t especially deep, it wasn’t especially long, it wasn’t especially anything. It was minor."
And, while the transmission event was uncommon, "it demonstrates that uncommon things do occur." What is the likelihood of a recurrence? "Teensy," Rex says.
"The likelihood of it occurring the first time was very small," he explains. "We’re very familiar with the spread of things like Mycobacterium tuberculosis and other [pathogens], but the spread of bacterial pathogens in such a direct fashion is not a commonplace occurrence, and it bears contemplation. Viremias, such as hepatitis, tend to be on the more constant side, whereas bacteremias actually are intermittent. You really have to be zapped with precisely the right drop of blood for a bacteremia to be transmitted in this fashion."
Rex says bacteremias "are typically quoted in densities of 100 organisms per cubic ml of blood, so you’d have a tenth of an organism per microliter [of blood] if you caught the patient while they were bacteremic."
However, with hepatitis B, the concentration of virus is about 1 billion particles per milliliter of blood, which is why hepatitis B is much more easily transmitted through a needlestick injury than a bacterial pathogen. A few microliters of hepatitis B-contaminated blood could contain many thousands of virus particles, "while in the case of bacterium, a few microliters of blood may not contain anything at all," Rex notes. "Over all of the hundreds of thousands of [infection transmissions] that have been reported over the last 30 years, transmission of a bacterial pathogen in this fashion remains an oddity."
Nevertheless, Hagberg an anesthesiologist who participated in the resident’s surgery remains concerned that a two-millimeter long injury similar in appearance and severity to a cat scratch could transmit a life-threatening infection.
"It’s unbelievable, but it shows just how strong the bug is," she states. "To me, it’s almost like a virus. It’s that deadly."
One possible reason the resident became infected is that the source patient may have been at the "peak" of disease, she adds.
Could it happen again to another HCW? "Oh yes. This is the first report, but I’m sure it has happened before and people weren’t aware of it. I’m wondering now that since this report has come out, we might see how many more [reports] come up," she says.
Hagberg advises HCWs to take the same precautions they would with AIDS patients.
"It’s flesh-eating bacteria, and it seems to be getting more virulent. Fortunately for [the resident], it was recognized, debrided, and they got rid of it. As an anesthesiologist, I am always sticking people. When I’m going to see a patient with necrotizing fasciitis, I’ll take the same precautions to protect myself from blood and secretions as I would with a patient with HIV. It’s that dangerous," Hagberg says. "There’s no doubt."
References
1. Hagberg C, Radulescu A, Rex JH. Necrotizing fasciitis due to group A streptococcus after an accidental needle-stick injury (Correspondence). N Engl J Med 1997; 337:1699.
2. Majeski J, Majeski E. Necrotizing fasciitis: Improved survival with early recognition by tissue biopsy and aggressive surgical treatment. South Med J 1997; 90:1065-1068.
3. Tsai CC, Lin SD, Lai CS, et al. A clinical analysis of necrotizing fasciitis: A review of 54 cases. Kao Hsiung I Hsueh Tsa Chih 1995; 11:673-677.
4. Stone DR, Gorbach SL. Necrotizing fasciitis: The changing spectrum. Dermatol Clin 1997; 15:213-220.
5. Kaul R, McGeer A, Low DE, et al. Population-based surveillance for group A streptococcal necrotizing fasciitis: Clinical features, prognostic indicators, and microbiologic analysis of seventy-seven cases. Ontario group A streptococcal study. Am J Med 1997; 103:18-24.
6. Valenzuela TD, Hooten TM, Kaplan EL, et al. Transmission of "toxic strep" syndrome from an infected child to a firefighter during CPR. Ann Emerg Med 1991; 20:90-92.
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