Archive for April, 2013

Molecular pathogenesis of infections caused by Legionella pneumophila.

Clin Microbiol Rev. 2010 Apr;23(2):274-98.

Newton HJ, Ang DK, van Driel IR, Hartland EL.

Source

Department of Microbiology and Immunology, University of Melbourne, Grattan Street, Parkville, Victoria 3010, Australia.

Abstract

The genus Legionella contains more than 50 species, of which at least 24 have been associated with human infection. The best-characterized member of the genus, Legionella pneumophila, is the major causative agent of Legionnaires’ disease, a severe form of acute pneumonia. L. pneumophila is an intracellular pathogen, and as part of its pathogenesis, the bacteria avoid phagolysosome fusion and replicate within alveolar macrophages and epithelial cells in a vacuole that exhibits many characteristics of the endoplasmic reticulum (ER). The formation of the unusual L. pneumophila vacuole is a feature of its interaction with the host, yet the mechanisms by which the bacteria avoid classical endosome fusion and recruit markers of the ER are incompletely understood. Here we review the factors that contribute to the ability of L. pneumophila to infect and replicate in human cells and amoebae with an emphasis on proteins that are secreted by the bacteria into the Legionella vacuole and/or the host cell. Many of these factors undermine eukaryotic trafficking and signaling pathways by acting as functional and, in some cases, structural mimics of eukaryotic proteins. We discuss the consequences of this mimicry for the biology of the infected cell and also for immune responses to L. pneumophila infection.

PDF

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2863363/pdf/0052-09.pdf

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April 30, 2013 at 2:51 pm

An outbreak of scabies in a teaching hospital – Lessons learned.

Infect Control Hosp Epidemiol. 2001 Jan;22(1):13-8.

Obasanjo OO, Wu P, Conlon M, Karanfil LV, Pryor P, Moler G, Anhalt G, Chaisson RE, Perl TM.

Source

Department of Epidemiology, Johns Hopkins School of Hygiene and Public Health, The Johns Hopkins University, Baltimore, MD, USA.

Abstract

OBJECTIVE:

To investigate an outbreak of scabies in an inner-city teaching hospital, identify pathways of transmission, institute effective control measures to end the outbreak, and prevent future occurrences.

DESIGN:

Outbreak investigation, case-control study, and chart review.

SETTING:

Large tertiary acute-care hospital.

RESULTS:

A patient with unrecognized Norwegian (crusted) scabies was admitted to the acquired immunodeficiency syndrome (AIDS) service of a 940-bed acute-care hospital. Over 4 months, 773 healthcare workers (HCWs) and 204 patients were exposed to scabies. Of the exposed HCWs, 147 (19%) worked on the AIDS service. Risk factors for being infested with scabies among HCWs included working on the AIDS service (odds ratio [OR], 5.3; 95% confidence interval [CI95], 2.17-13.15) and being a nurse, physical therapist, or HCW with extensive physical contact with infected patients (OR, 4.5; CI95, 1.26-17.45). Aggressive infection control precautions beyond Centers for Disease Control and Prevention barrier and isolation recommendations were instituted, including the following: (1) early identification of infected patients; (2) prophylactic treatment with topical applications for all exposed HCWs; (3) use of two treatments 1 week apart for all cases of Norwegian scabies; (4) maintaining isolation for 8 days and barrier precautions for 24 hours after completing second treatment for a diagnosis of Norwegian scabies; and (5) oral ivermectin for treatment of patients who failed conventional therapy.

CONCLUSIONS:

HCWs with the most patient contact are at highest risk of acquiring scabies. Because HCWs who used traditionally accepted barriers while caring for patients with Norwegian scabies continued to develop scabies, we found additional measures were required in the acute-care hospital. HCWs with skin exposure to patients with scabies should receive prophylactic treatment. We recommend (1) using heightened barrier precautions for care of patients with scabies and (2) extending the isolation period for 8 days or 24 hours after the second treatment with a scabicide for those patients with Norwegian scabies. Oral ivermectin was well tolerated for treating patients and HCWs who failed conventional treatment. Finally, we developed a surveillance system that provides a “barometric measure” of the infection rate in the community. If scabies increases in the community, a tiered triage system is activated to protect against transmission among HCWs or hospital patients.

abstract

http://www.jstor.org/stable/10.1086/501818#abstract

PDF

http://www.jstor.org/stable/pdfplus/10.1086/501818.pdf?acceptTC=true

April 30, 2013 at 2:47 pm

Increased risk of prosthetic joint infection associated with esophago-gastro-duodenoscopy with biopsy.

Acta Orthop. 2013 Feb;84(1):82-6.

Coelho-Prabhu N, Oxentenko AS, Osmon DR, Baron TH, Hanssen AD, Wilson WR, Steckelberg JM, Baddour LM, Harmsen WS, Mandrekar J, Berbari EF.

Source

Division of Gastroenterology, Mayo Clinic, Rochester, MN, USA.

Abstract

BACKGROUND:

There are no prospective data regarding the risk of prosthetic joint infection following routine gastrointestinal endoscopic procedures. We wanted to determine the risk of prosthetic hip or knee infection following gastrointestinal endoscopic procedures in patients with joint arthroplasty.

METHODS:

We conducted a prospective, single-center, case-control study at a single, tertiary-care referral center. Cases were defined as adult patients hospitalized for prosthetic joint infection of the hip or knee between December 1, 2001 and May 31, 2006. Controls were adult patients with hip or knee arthroplasties but without a diagnosis of joint infection, hospitalized during the same time period at the same orthopedic hospital. The main outcome measure was the odds ratio (OR) of prosthetic joint infection after gastrointestinal endoscopic procedures performed within 2 years before admission.

RESULTS:

339 cases and 339 controls were included in the study. Of these, 70 cases (21%) cases and 82 controls (24%) had undergone a gastrointestinal endoscopic procedure in the preceding 2 years. Among gastrointestinal procedures that were assessed, esophago-gastro-duodenoscopy (EGD) with biopsy was associated with an increased risk of prosthetic joint infection (OR = 3, 95% CI: 1.1-7). In a multivariable analysis adjusting for sex, age, joint age, immunosuppression, BMI, presence of wound drain, prior arthroplasty, malignancy, ASA score, and prothrombin time, the OR for infection after EGD with biopsy was 4 (95% CI: 1.5-10).

INTERPRETATION:

EGD with biopsy was associated with an increased risk of prosthetic joint infection in patients with hip or knee arthroplasties. This association will need to be confirmed in other epidemiological studies and adequately powered prospective clinical trials prior to recommending antibiotic prophylaxis in these patients.

PDF

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3584609/pdf/ORT-84-82.pdf

April 30, 2013 at 2:42 pm

Hand hygiene practices and resources in a teaching hospital in Ghana.

J Infect Dev Ctries. 2013 Apr 17;7(4):338-47.

Yawson AE, Hesse AA.

Source

Korle-Bu Teaching Hospital, Korle-Bu, Accra, Ghana. aeyawson@yahoo.com.

Abstract

INTRODUCTION:

Nosocomial infections have long been neglected in Sub-Saharan Africa, and hand hygiene (HH) is usually neglected in hospital settings. This study aimed to provide baseline data on HH compliance among health workers and HH resources in a large West African teaching hospital.

METHODOLOGY:

A cross-sectional, unobtrusive observational study assessed personal and care-related HH compliance among doctors and nurses and HH resources in 15 service provision centres of the Korle-Bu Teaching Hospital (KBTH), Ghana, in 2011. Data was collected with an infection prevention checklist and health worker HH compliance form, based on World Health Organization guidelines.

RESULTS:

Care-related HH compliance of doctors and nurses was low and basic HH resources were deficient in all 15 service centres. Care-related HH compliance among doctors ranged from 9.2% to 57% and 9.6% to 54% among nurses. HH compliance was higher when risk was perceived to be higher (i.e., in the emergency and wound dressing/treatment rooms and labour wards). The neonatal intensive care unit (NICU) showed the highest level of compliance among health workers. Facilities for HH, particularly alcohol hand rub and liquid soap dispensers were shown to be deficient.

CONCLUSIONS:

Care-related HH compliance among doctors and nurses in this large West African hospital is low; however, the NICU, which had implemented HH interventions, had better HH compliance. HH intervention programs should be designed and promoted in all service centres. Also, the introduction of alcohol-based hand rubs as an accessible and effective HH alternative in Korle-Bu Teaching Hospital is recommended.

PDF

http://www.jidc.org/index.php/journal/article/view/23592644/863

April 30, 2013 at 2:36 pm

Isolation and characterization of H7N9 viruses from live poultry markets

Chinese Science Bulletin April 2013

SHI JianZhong1†, DENG GuoHua1†, LIU PeiHong2, ZHOU JinPing2, GUAN LiZheng1, LI WenHui1, LI XuYong, GUO Jing1, WANG GuoJun1, FAN Jun1, WANG JinLiang1, LI YuanYuan1, JIANG YongPing1, LIU LiLing1, TIAN GuoBin1, LI ChengJun1* & CHEN HuaLan1*

1 Animal Influenza Laboratory, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute,

Chinese Academy of Agricultural Sciences, Harbin 150001, China;

2 Shanghai Animal Disease Control Center, Shanghai 201103, China

On March 31, 2013, the National Health and Family Planning Commission announced that human infections with a previously undescribed influenza A (H7N9) virus had occurred in Shanghai and Anhui Province, China. To investigate the possible origins of the H7N9 viruses causing these human infections, we collected 970 samples, including drinking water, soil, and cloacal and tracheal swabs of poultry from live poultry markets and poultry farms in Shanghai and AnhuiProvince. Twenty samples were positive for the H7N9 influenza virus. Notably, all 20 viruses were isolated from samples collected from live poultry markets in Shanghai. Phylogenetic analyses showed that the six internal genes of these novel human H7N9 viruses were derived from avian H9N2 viruses, but the ancestor of their HA and NA genes is uncertain. When we examined the phylogenetic relationship between the H7N9 isolates from live poultry markets and the viruses that caused the human infections, we found that they shared high homology across all eight gene segments. We thus identified the direct avian origin of the H7N9 influenza viruses that caused the human infections. Importantly, we observed that the H7N9 viruses isolated from humans had acquired critical mutations that made them more “human-like”. It is therefore imperative to take strong measures to control the spread of H7N9 viruses in birds and humans to prevent further threats to human health.

PDF

http://link.springer.com/content/pdf/10.1007%2Fs11434-013-5873-4.pdf

April 26, 2013 at 8:38 am

Preliminary Report: Epidemiology of the Avian Influenza A (H7N9) Outbreak in China

N Engl J of Medic April 24, 2013

Qun Li, M.D., Lei Zhou, M.D., Minghao Zhou, Ph.D., Zhiping Chen, M.D., Furong Li, M.D., Huanyu Wu, M.D., Nijuan Xiang, M.D., Enfu Chen, M.P.H., Fenyang Tang, M.D., Dayan Wang, M.D., Ling Meng, M.D., Zhiheng Hong, M.D., Wenxiao Tu, M.D., Yang Cao, M.D., Leilei Li, Ph.D., Fan Ding, M.D., Bo Liu, M.D., Mei Wang, M.D., Rongheng Xie, M.D., Rongbao Gao, M.D., Xiaodan Li, M.D., Tian Bai, M.D., Shumei Zou, M.D., Jun He, M.D., Jiayu Hu, M.D., Yangting Xu, M.D., Chengliang Chai, M.D., Shiwen Wang, M.D., Yongjun Gao, M.D., Lianmei Jin, M.D., Yanping Zhang, M.D., Huiming Luo, M.D., Hongjie Yu, M.D., M.P.H., Lidong Gao, M.D., Xinghuo Pang, M.D., Guohua Liu, M.D., Yuelong Shu, Ph.D., Weizhong Yang, M.D., Timothy M. Uyeki, M.D., M.P.H., M.P.P., Yu Wang, M.D., Fan Wu, M.D., and Zijian Feng, M.D., M.P.H.

BACKGROUND

The first identified cases of avian influenza A (H7N9) virus infection in humans occurred in China during February and March 2013. We analyzed data obtained from field investigations to characterize the epidemiologic characteristics of H7N9 cases in China as of April 17, 2013.

METHODS

Field investigations were conducted for each confirmed case of H7N9 virus infection. A patient was considered to have a confirmed case if the presence of the H7N9 virus was verified by means of real-time reverse-transcriptase–polymerase-chain-reaction (RT-PCR), viral isolation, or serologic testing. Information on demographic characteristics, exposure history, and illness timelines was obtained from patients with confirmed cases. Close contacts were monitored for 7 days for symptoms of illness. Throat swabs were obtained from contacts in whom symptoms developed and were tested for the presence of the H7N9 virus testing by means of real-time RT-PCR.

RESULTS

Among 82 persons with confirmed H7N9 virus infection, the median age was 63 years (range, 2 to 89), 73% were male, and 84% were urban residents. Confirmed cases occurred in six areas of China. Of 77 persons with available data, 4 were poultry workers, and 77% had a history of exposure to live animals, including chickens (76%). A total of 17 persons (21%) died after a median duration of illness of 11 days, 60 remain critically ill, and 4 with clinically mild cases were discharged from the hospital; 1 pediatric patient was not admitted to the hospital. In two family clusters, human-to-human transmission of H7N9 virus could not be ruled out. A total of 1251 of the 1689 close contacts of case patients completed the monitoring period; respiratory symptoms developed in 19 of them (1.5%), all of whom tested negative for the H7N9 virus.

CONCLUSIONS

Most persons with confirmed H7N9 virus infection were critically ill and epidemiologically unrelated. Laboratory-confirmed human-to-human H7N9 virus transmission was not documented among close contacts, but such transmission could not be ruled out in two families.

PDF

http://www.nejm.org/doi/pdf/10.1056/NEJMoa1304617

April 24, 2013 at 10:27 pm

Advisory Committee on Immunization Practices (ACIP) recommended immunization schedule for persons aged 0 through 18 years–United States, 2013.

MMWR Surveill Summ. 2013 Feb 1;62 Suppl 1:2-8.

ACIP Childhood/Adolescent Immunization Work Group, Akinsanya-Beysolow I, Jenkins R, Meissner HC; Centers for Disease Control and Prevention (CDC).

Collaborators (21)

Jenkins R, Karron R, Rubin LG, Meissner H, Middleman AB, Lett S, Peterson D, Barry C, Schlamm E, Brewer K, Stinchfield P, Spence R, Kroger A, Atkinson WL, Hamborsky J, Wolfe C, Weaver D, Wolicki J, Barnett M, Mirza Z, Akinsanya-Beysolow I.

FULL TEXT

http://www.cdc.gov/mmwr/preview/mmwrhtml/su6201a2.htm

PDF

http://www.cdc.gov/mmwr/pdf/other/su6201.pdf

 

ERRATUM

FULL TEXT

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6213a6.htm?s_cid=mm6213a6_w

PDF

http://www.cdc.gov/mmwr/pdf/wk/mm6213.pdf

April 24, 2013 at 10:25 pm

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