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Volume 18, Number 6—June 2012

Volume 18, Number 6—June 2012   PDF Version [PDF - 4.51 MB - 147 pages]

Synopses

  • Medscape CME Activity
    Iatrogenic Creutzfeldt-Jakob Disease, Final Assessment PDF Version [PDF - 291 KB - 7 pages]
    P. Brown et al.
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    The book on iatrogenic Creutzfeldt-Jakob disease (CJD) in humans is almost closed. This form of CJD transmission via medical misadventures was first detected in 1974. Today, only occasional CJD cases with exceptionally long incubation periods still appear. The main sources of the largest outbreaks were tissues from human cadavers with unsuspected CJD that were used for dura mater grafts and growth hormone extracts. A few additional cases resulted from neurosurgical instrument contamination, corneal grafts, gonadotrophic hormone, and secondary infections from blood transfusions. Although the final solution to the problem of iatrogenic CJD is still not available (a laboratory test to identify potential donors who harbor the infectious agent), certain other measures have worked well: applying special sterilization of penetrating surgical instruments, reducing the infectious potential of donor blood and tissue, and excluding donors known to have higher than normal risk for CJD.

       View Abstract

    The era of iatrogenic Creutzfeldt-Jakob disease (CJD) has nearly closed; only occasional cases with exceptionally long incubation periods are still appearing. The principal sources of these outbreaks are contaminated growth hormone (226 cases) and dura mater grafts (228 cases) derived from human cadavers with undiagnosed CJD infections; a small number of additional cases are caused by neurosurgical instrument contamination, corneal grafts, gonadotrophic hormone, and secondary infection with variant CJD transmitted by transfusion of blood products. No new sources of disease have been identified, and current practices, which combine improved recognition of potentially infected persons with new disinfection methods for fragile surgical instruments and biological products, should continue to minimize the risk for iatrogenic disease until a blood screening test for the detection of preclinical infection is validated for human use.

Research

  • Medscape CME Activity
    Pretransplant Fecal Carriage of Extended-Spectrum β-Lactamase–producing Enterobacteriaceae and Infection after Liver Transplant, France PDF Version [PDF - 385 KB - 9 pages]
    F. Bert et al.
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    Bacterial infection after liver transplant is fairly common, mostly because liver transplant patients are severely ill and the surgery is very complex. Adding to the seriousness of this situation is that some bacteria are resistant to many antimicrobial drugs. However, treating all infections as drug resistant would lead to even more drug resistance, so only patients at highest risk should receive the most powerful drugs. But who is at highest risk? A recent study in France screened fecal samples of liver transplant candidates and found that post-operative infections were most likely for those patients who already had certain bacteria in their feces before surgery. Thus, fecal screening for those multiresistant bacteria should be considered for all liver transplant candidates so that if post-operative infection develops, those at high risk can receive the most specific drugs right away.

       View Abstract

    Extended-spectrum β-lactamase–producing Enterobacteriaceae isolates (ESBLE) are emerging pathogens that confer resistance to antimicrobial drugs. We conducted a 10-year study in France (January 2001–April 2010) to investigate the incidence of and risk factors for ESBLE infections after liver transplant. Of 710 transplant patients screened preoperatively for ESBLE fecal carriage, 5.5% had ESBLE infection develop within 4 months after surgery; patients with pretransplant ESBLE fecal carriage were more likely to have infection develop than were noncarriers. Typing showed extensive genetic diversity, with a large predominance of CTX-M enzymes. Independent predictors of ESBLE infection were pretransplant fecal carriage, Model for End Stage Liver Disease score >25, and return to surgery. Our results indicate that the influx of preoperatively acquired ESBLE isolates into the hospital outweighs cross-transmission in the epidemiology of ESBLE infections after liver transplant. Transplant candidates should be systematically screened for carriage, and posttransplant infection in carriers should be treated with carbapenems.

  • Medscape CME Activity
    Trends in Invasive Infection with Methicillin-Resistant Staphylococcus aureus, Connecticut, USA, 2001–2010 PDF Version [PDF - 270 KB - 8 pages]
    J. L. Hadler et al.
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    Decreases in health care–related isolates accounted for all reductions in MRSA during 2007–2010.

       View Abstract

    We examined trends in incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections in Connecticut, with emphasis on 2007–2010, after legislation required reporting of hospital infections. A case was defined as isolation of MRSA from normally sterile body sites, classified after medical record review as hospital onset (HO), community onset, health care–associated community onset (HACO), or community-associated (CA). Blood isolates collected during 2005–2010 were typed and categorized as community- or health care–related strains. During 2001–2010, a total of 8,758 cases were reported (58% HACO, 31% HO, and 11% CA), and MRSA incidence decreased (p<0.05) for HACO and HO, but increased for CA. Significant 3- to 4-year period trends were decreases in all MRSA (–18.8%), HACO (–12.8%), HO (–33.2%), and CA (–12.7%) infections during 2007–2010, and an increase in CA infections during 2004–2006. Decreases in health care–related isolates accounted for all reductions. Hospital infections reporting may have catalyzed the decreases.

  • Molecular Epidemiology of Geographically Dispersed Vibrio cholerae, Kenya, January 2009–May 2010 PDF Version [PDF - 329 KB - 7 pages]
    A. Mohamed et al.
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    Isolates represent multiple genetic lineages, a finding consistent with multiple emergences from endemic reservoirs.

       View Abstract

    Numerous outbreaks of cholera have occurred in Kenya since 1971. To more fully understand the epidemiology of cholera in Kenya, we analyzed the genetic relationships among 170 Vibrio cholerae O1 isolates at 5 loci containing variable tandem repeats. The isolates were collected during January 2009–May 2010 from various geographic areas throughout the country. The isolates grouped genetically into 5 clonal complexes, each comprising a series of genotypes that differed by an allelic change at a single locus. No obvious correlation between the geographic locations of the isolates and their genotypes was observed. Nevertheless, geographic differentiation of the clonal complexes occurred. Our analyses showed that multiple genetic lineages of V. cholerae were simultaneously infecting persons in Kenya. This finding is consistent with the simultaneous emergence of multiple distinct genetic lineages of V. cholerae from endemic environmental reservoirs rather than recent introduction and spread by travelers.

  • Community Survey after Rabies Outbreaks, Flagstaff, Arizona, USA PDF Version [PDF - 226 KB - 7 pages]
    A. M. McCollum et al.
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    Educational outreach should inform the public about dangers of translocation of wild animals and general aspects of rabies.

       View Abstract

    Flagstaff, Arizona, USA, experienced notable outbreaks of rabies caused by a bat rabies virus variant in carnivore species in 2001, 2004, 2005, 2008, and 2009. The most recent epizootic involved transmission among skunk and fox populations and human exposures. Multiple, wide-ranging control efforts and health communications outreach were instituted in 2009, including a household survey given to community members. Although the Flagstaff community is knowledgeable about rabies and the ongoing outbreaks in general, gaps in knowledge about routes of exposure and potential hosts remain. Future educational efforts should include messages on the dangers of animal translocation and a focus on veterinarians and physicians as valuable sources for outreach. These results will be useful to communities experiencing rabies outbreaks as well as those at current risk.

  • Trichomonas vaginalis Antimicrobial Drug Resistance in 6 US Cities, STD Surveillance Network, 2009–2010 PDF Version [PDF - 333 KB - 5 pages]
    R. D. Kirkcaldy et al.
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    Such isolates should undergo drug susceptibility testing periodically to detect emerging resistance.

       View Abstract

    Nitroimidazoles (metronidazole and tinidazole) are the only recommended drugs for treating Trichomonas vaginalis infection, and previous samples that assessed resistance of such isolates have been limited in geographic scope. We assessed the prevalence of in vitro aerobic metronidazole and tinidazole resistance among T. vaginalis isolates from multiple geographic sites in the United States. Swab specimens were obtained from women who underwent routine pelvic examinations at sexually transmitted disease clinics in 6 US cities. Cultured T. vaginalis isolates were tested for nitroimidazole resistance (aerobic minimum lethal concentration [MLC] >50 µg/mL). Of 538 T. vaginalis isolates, 23 (4.3%) exhibited low-level in vitro metronidazole resistance (minimum lethal concentrations 50–100 µg/mL). No isolates exhibited moderate- to high-level metronidazole resistance or tinidazole resistance. Results highlight the possibility that reliance on a single class of antimicrobial drugs for treating T. vaginalis infections may heighten vulnerability to emergence of resistance. Thus, novel treatment options are needed.

  • Virulence Potential of Fusogenic Orthoreoviruses PDF Version [PDF - 301 KB - 5 pages]
    A. H. Wong et al.
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    Virus evolution should be monitored because frequent reassortment, which contributes to virus diversity, creates the potential for more severe infections.

       View Abstract

    Several severe respiratory virus infections that have emerged during the past decade originated in animals, including bats. In Indonesia, exposure to bats has been associated with increased risk of acquiring orthoreovirus infection. Although orthoreovirus infections are mild and self-limiting, we explored their potential for evolution into a more virulent form. We used conventional virus culture, electron microscopy, and molecular sequencing to isolate and identify orthoreoviruses from 3 patients in whom respiratory tract infection developed after travel to Indonesia. Virus characterization by plaque-reduction neutralization testing showed antigenic similarity, but sequencing of the small segment genes suggested virus reassortment, which could lead to increased virulence. Bats as a reservoir might contribute to virus evolution and genetic diversity, giving orthoreoviruses the potential to become more virulent. Evolution of this virus should be closely monitored so that prevention and control measures can be taken should it become more virulent.

  • Intrafamilial Circulation of Tropheryma whipplei, France PDF Version [PDF - 283 KB - 7 pages]
    F. Fenollar et al.
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    High prevalence within families might reflect a specific immune condition.

       View Abstract

    Tropheryma whipplei, which causes Whipple disease, has been detected in 4% of fecal samples from the general adult population of France. To identify T. whipplei within families, we conducted serologic and molecular studies, including genotyping, on saliva, feces, and serum from 74 relatives of 13 patients with classic Whipple disease, 5 with localized chronic T. whipplei infection, and 3 carriers. Seroprevalence was determined by Western blot and compared with 300 persons from the general population. We detected T. whipplei in 24 (38%) of 64 fecal samples and 7 (10%) of 70 saliva samples from relatives but found no difference between persons related by genetics and marriage. The same circulating genotype occurred significantly more often in families than in other persons. Seroprevalence was higher among relatives (23 [77%] of 30) than in the general population (143 [48%] of 300). The high prevalence of T. whipplei within families suggests intrafamilial circulation.

  • Human Gyrovirus DNA in Human Blood, Italy PDF Version [PDF - 205 KB - 4 pages]
    F. Maggi et al.
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    HGyV in blood suggests the infection might be systemic.

       View Abstract

    Human gyrovirus (HGyV) is a recent addition to the list of agents found in humans. Prevalence, biologic properties, and clinical associations of this novel virus are still incompletely understood. We used qualitative PCRs to detect HGyV in blood samples of 301 persons from Italy. HGyV genome was detected in 3 of 100 solid organ transplant recipients and in 1 HIV-infected person. The virus was not detected in plasma samples from healthy persons. Furthermore, during observation, persons for whom longitudinal plasma samples were obtained had transient and scattered presence of circulating HGyV. Sequencing of a 138-bp fragment showed nucleotide identity among all the HGyV isolates. These results show that HGyV can be present in the blood of infected persons. Additional studies are needed to investigate possible clinical implications.

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