Updates
By Carol A. Kemper, MD, FACP, Section Editor: Updates, Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases; Santa Clara Valley Medical Center, is Associate Editor for Infectious Disease Alert.
Endocarditis of implanted Valves
Puls M, et al. Infection of percutaneously implanted prosthetic aortic valves. EuroIntervention 2012 Sep 27. doi:pii:20120625-03 [Epub ahead of print].
Eisen A, et al. Infective endocarditis in the transcatheter aortic replacement era: comprehensive review of a rare complication. Clin Cardiol 2012 Sept 18. doi:10.1002/clc.22052. [Epub ahead of print].
I was recently asked to provide consultation for a 92-year-old woman with an aortic CoreValve who presented with a pacer pocket infection secondary to MRSA. Blood cultures had not been obtained prior to the initiation of antimicrobials but both leads on extraction proved positive for MRSA. Both transthoracic and transesophageal echocardiograms showed no evidence of CoreValve vegetation, although there was a modest paravalvular leak. How to evaluate and treat this woman?
Puls and colleagues evaluated the first 180 consecutive patients to undergo TAVR at their institution, finding a one-year incidence of TAVR endocarditis of 3.4% based on Duke criteria. This figure may be inflated, as the Duke criteria include paravalvular leaks. However, paravalvular regurgitation is quite common with TAVR, and moderate to severe “leaks” are reported in 7% to 20% of patients. Based on a search of the literature, the incidence of endocarditis involving percutaneously implantable valve devices may vary from as little as 0% to up to 2.3%, with varying durations of follow-up. Eisen and colleagues reported 10 cases, six involving CoreValves and 4 involving SAPIEN valves. Infections were due to Staphylococcus lugdenensis (n = 2), enterococcus (n = 2), and candida albicans (n = 2 ), as well as S epidermis, Streptococcus angiosus, Moraxella nonliquefaciens, corynebacterium, and Histoplasma capsulatum. Four of the 10 patients died, all within 14-54 days. Two patients required surgical valve replacement.
Suspicion for infection of percutaneously implantable prosthetic aortic valves should remain high in the appropriate clinical circumstances, similar to that for surgically implanted prosthetic valves, although the usual echocardiographic features may be misleading.
Pumas with Lyme?
Girard YA, et al. Zoonotic vector-born bacterial pathogens in California Mountain Lions (Puma concolor), 1987-2010. Vector Borne Zoonotic Dis 2012;(11):913-921.
Active infectious disease surveillance of the California Mountain Lion population yields some interesting results, in terms of diseases that also affect humans. Sera was obtained from 442 Mountain Lions throughout California from 1987-2010, 70% of which were killed on depredation permits (meaning they were exhibiting predatory habits proximate to residential communities or livestock areas). Antibody studies demonstrated that exposure to Bartonella henselae and Borrelia burgdorferi were quite common, found in 37.1% and 19.9% of animals tested, respectively. B henselae DNA extracted from samples was similar to common strains of this organism found in domestic cats and humans.
Antibodies to Yersinia pestis were observed in 7 (1.4%) animals, all of which were female, and found on the Eastern and Western Sierra Nevadas. And, antibody evidence of exposure to Francisella tularensis (1.4%) and Anaplasma phagocytophilum (5.9%) was less common.
The high rate of exposure to lyme disease may not be surprising, as deer are a dietary staple for Mountain Lions – but one wonders if they ever develop symptomatic disease. Humans are at little risk for acquiring zoonotic infections from Mountain Lions, even if you could get that close. But game wardens and rescue centers should be cognizant of these possibilities.
The Smell of C Difficile
Rao, K, et al. The Nose knows not: poor predictive value of stool sample odor for detection of Clostridium difficile. Clin Infect Dis 2012;Nov. 19. Epub ahead of print).
Ever walked by a patient room and thought – ahah! C. diff ? It is theoretically possible to detect the presence of C. difficile enterocolitis (CDI) based on the odor. Unique volatile organic compounds may be detected in the stools of patients with CDI. Gas chromatography can effectively distinguish 100% of the time between the stools of CDI patients and those with ulcerative colitis or other gastroenteritis. But can medical staff do the same? And could a protocol for contact isolation be built around this observation ?
These authors recruited 18 nursing staff from hospital wards, and presented them with 10 blinded stool samples. Five samples were positive for CDI and 5 were negative based on PCR and toxin immunoassay results. The nurses varied in experience from 1 to 30 years with 8 of the 18 having more than 10 years of experience.
After sniffing and scoring each sample, 61% expressed confidence in their guesses. The median percent correct was 45%. Positive specimens were more likely to be scored incorrectly than negative ones (69% vs 26%, respectively, p = .01). Those with confidence in their sniffing abilities and / or more experience were no more likely to be correct than those with less confidence or less experience. In fact, the authors state that no single sniffer did better than random chance.
I am not convinced by this study — blinded or not — and still confident of my sniffing abilities! One wonders if the volatile components given off by the collected specimens had waned sufficiently by the time the nurses were gathered together for the study. Perhaps there is something about the smell of a freshly passed stool by a patient lying in bed, than in a cup in the lab.
STD Screening of the Adult Film Industry
Rodriquez-Hart C, et al. Sexually transmitted infection testing of adult film performers: Is disease being missed? Sex Transm Dis 2012;(39(12):989-994.
Active STD surveillance of the adult film industry in many parts of the United States is a requirement. It might seem odd that the bureaucrats of Cal-OSHA are responsible for establishing the rules regulating the sex film industry, but when sex becomes work, risk becomes subject to regulation. The State of California requires any adult film worker to be screened and certified STD-free, based on blood and urine testing, within 30 days of performance. However, even regular monthly STD screening is fallible, as demonstrated by the transmission of HIV among adult film workers in 2004, from a man who fell into the classical “window” period with previously negative monthly serological screening specimens. Over the next month, three of his 13 female film partners converted their HIV tests, after having been screened negative in the preceding month.1
This study suggests that current screening methods could be expanded. Between May and September 2010, 168 adult film workers were offered more expanded STD screening with GC and chlamydia testing of oropharyngeal, rectal and urogenital specimens. Two-thirds of the participants were female. Not surprisingly, gonorrhea and chlamydia infections involving the rectum and the oropharynx would have been missed based on current urine screening methods. But the frequency of these infections was surprising. Forty-seven persons (28%) tested positive for GC and/or chlamydia, nearly one-fourth of which would have been missed based on current screening requirements. Gonorrhea was predominant, resulting in 37 oropharyngeal infections and 23 rectal infections, 95% and 91% of which, respectively, were asymptomatic.
The nature of the adult film business results in frequent exposure to multiple sex partners – with varying sites of anatomic involvement. For this reason, it makes sense to expand STD screening to those other sites (oropharyngeal and rectal), irrespective of symptoms. Adult film workers should be aware that STD screening is not a guarantor of disease-free status, and there are inherent risks to their job. Caution outside the work place, with strict adherence to safe sex practices and condom use, would improve the risks in the work place.
- CDC. HIV transmission in the Adult Film Industry – Los Angeles, California, 2004; MMWR 2005;54(37):923-926.
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