Archive for June 19, 2011

Dose-response Effect of Incarceration Events on Nonadherence to HIV Antiretroviral Therapy Among Injection Drug Users

Journal of Infectious Diseases  May 1, 2011 V.203 N.9 P.1215-1221

M. J. Milloy1,2, Thomas Kerr1,3, Jane Buxton2,4, Tim Rhodes5, Silvia Guillemi1, Robert Hogg1, Julio Montaner1,3 and Evan Wood1,3

1British Columbia Centre for Excellence in HIV/AIDS, St. Paul’s Hospital

2School of Population and Public Health

3Department of Medicine, University of British Columbia

4British Columbia Centre for Disease Control, Vancouver, Canada

5London School of Hygiene and Tropical Medicine, University of London, United Kingdom


Although some studies have identified impressive clinical gains for incarcerated HIV-seropositive injection drug users (IDUs) undergoing antiretroviral therapy (ART), the effect of incarceration on adherence to ART remains undetermined.


We used data from a long-term community-recruited cohort of HIV-seropositive IDUs, including comprehensive ART dispensation records, in a setting where HIV care is free. We estimated the relationship between the cumulative burden of incarceration, measured longitudinally, and the odds of <95% adherence to ART, with use of multivariate modeling.


From 1996 through 2008, 490 IDUs were recruited and contributed 2220 person-years of follow-up; 271 participants (55.3%) experienced an incarceration episode, with the number of incarcerations totaling1156. Ina multivariate model, incarceration had a strong dose-dependent effect on the likelihood of nonadherence to ART: 1-2 incarceration events (adjusted odds ratio [AOR], 1.49; 95% confidence interval [95% CI], 1.03–2.05), 3–5 events (AOR, 2.48; 95% CI, 1.62–3.65), and > 5 events (AOR, 3.11; 95% CI, 1.86–4.95).


Among HIV-seropositive IDUs receiving ART, an increasing burden of incarceration was associated with poorer adherence in a dose-dependent fashion. Our findings support improved adherence support for HIV-seropositive IDUs experiencing incarceration.



June 19, 2011 at 6:57 pm Leave a comment

Community-Associated Methicillin-Resistant Staphylococcus aureus: Epidemiology and Clinical Consequences of an Emerging Epidemic

Clinical Microbiology Reviews July 2010 V.23 N.3 P.616-687

Michael Z. David* and Robert S. Daum

Section of Infectious Diseases, Department of Pediatrics, the University of Chicago, Chicago, Illinois


Staphylococcus aureus is an important cause of skin and soft-tissue infections (SSTIs), endovascular infections, pneumonia, septic arthritis, endocarditis, osteomyelitis, foreign-body infections, and sepsis. Methicillin-resistant S. aureus (MRSA) isolates were once confined largely to hospitals, other health care environments, and patients frequenting these facilities. Since the mid-1990s, however, there has been an explosion in the number of MRSA infections reported in populations lacking risk factors for exposure to the health care system. This increase in the incidence of MRSA infection has been associated with the recognition of new MRSA clones known as community-associated MRSA (CA-MRSA). CA-MRSA strains differ from the older, health care-associated MRSA strains; they infect a different group of patients, they cause different clinical syndromes, they differ in antimicrobial susceptibility patterns, they spread rapidly among healthy people in the community, and they frequently cause infections in health care environments as well. This review details what is known about the epidemiology of CA-MRSA strains and the clinical spectrum of infectious syndromes associated with them that ranges from a commensal state to severe, overwhelming infection. It also addresses the therapy of these infections and strategies for their prevention.


June 19, 2011 at 6:54 pm Leave a comment

The Changing Epidemiology of Clostridium difficile Infections

Clinical Microbiology Reviews July 2010 V.23 N.3 P.529-549       

J. Freeman,1 M. P. Bauer,2 S. D. Baines,1 J. Corver,2 W. N. Fawley,1 B. Goorhuis,2 E. J. Kuijper,2 and M. H. Wilcox1*

Department of Microbiology, Old Medical School, Leeds Teaching Hospitals and University of Leeds, Leeds, United Kingdom,1 Departments of Medical Microbiology and Infectious Diseases, Centre for Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands2


The epidemiology of Clostridium difficile infection (CDI) has changed dramatically during this millennium. Infection rates have increased markedly in most countries with detailed surveillance data. There have been clear changes in the clinical presentation, response to treatment, and outcome of CDI. These changes have been driven to a major degree by the emergence and epidemic spread of a novel strain, known as PCR ribotype 027 (sometimes referred to as BI/NAP1/027). We review the evidence for the changing epidemiology, clinical virulence and outcome of treatment of CDI, and the similarities and differences between data from various countries and continents. Community-acquired CDI has also emerged, although the evidence for this as a distinct new entity is less clear. There are new data on the etiology of and potential risk factors for CDI; controversial issues include specific antimicrobial agents, gastric acid suppressants, potential animal and food sources of C. difficile, and the effect of the use of alcohol-based hand hygiene agents.


June 19, 2011 at 6:52 pm Leave a comment

Epidemiology, Diagnosis, and Antimicrobial Treatment of Acute Bacterial Meningitis

Clinical Microbiology Reviews July 2010 V.23 N.3 P.467-492

Matthijs C. Brouwer,1 Allan R. Tunkel,2 and Diederik van de Beek1*

Department of Neurology, Center of Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands,1 Department of Medicine, Monmouth Medical Center, Long Branch, New Jersey2


The epidemiology of bacterial meningitis has changed as a result of the widespread use of conjugate vaccines and preventive antimicrobial treatment of pregnant women. Given the significant morbidity and mortality associated with bacterial meningitis, accurate information is necessary regarding the important etiological agents and populations at risk to ascertain public health measures and ensure appropriate management. In this review, we describe the changing epidemiology of bacterial meningitis in theUnited Statesand throughout the world by reviewing the global changes in etiological agents followed by specific microorganism data on the impact of the development and widespread use of conjugate vaccines. We provide recommendations for empirical antimicrobial and adjunctive treatments for clinical subgroups and review available laboratory methods in making the etiological diagnosis of bacterial meningitis. Finally, we summarize risk factors, clinical features, and microbiological diagnostics for the specific bacteria causing this disease.


June 19, 2011 at 6:50 pm Leave a comment

Impact of guideline-consistent therapy on outcome of patients with healthcare-associated and community-acquired pneumonia

Journal of Antimicrobial Chemotherapy July 2011 V.66 N.7 P.1617-1624

Cynthia Grenier, Jacques Pépin, Vincent Nault, Jessika Howson, Xavier Fournier, Marie-Sol Poirier, Jérôme Cabana, Camille Craig, Mathieu Beaudoin and Louis Valiquette*

Department of Microbiology and Infectious Diseases, Université de Sherbrooke, Sherbrooke, Québec, Canada



A new category of healthcare-associated pneumonia (HCAP) has been added in the most recent American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) guidelines, since multidrug-resistant (MDR) pathogens are more common in patients with HCAP than in those with community-acquired pneumonia (CAP). The optimal empirical management of patients with HCAP remains controversial and adherence to guidelines is inconsistent.


A retrospective cohort study of 3295 adults admitted for pneumonia in an academic centre ofCanada, between 1997 and 2008.


MDR pathogens were more common among patients with HCAP than in those with CAP, but less so than in other studies. Compared with patients with CAP, those with HCAP had a higher all-cause 30 day mortality [68/563 (12%) versus 201/2732 (7%); P < 0.001] and more frequent need for mechanical ventilation [78/563 (14%) versus 276/2732 (10%); P = 0.01]. In patients with CAP, mortality was lower when treatment was concordant with guidelines [86/1557 (6%) versus 109/1097 (10%) if discordant; adjusted odds ratio 0.6 (0.4–0.8); P < 0.001]. In HCAP, mortality was similar whether or not empirical treatment was concordant with guidelines [6/35 (17%) versus 18/148 (12%) if discordant; P = 0.4]. However, 30 day mortality tended to be higher when the empirical treatment was microbiologically ineffective [4/22 (18%) versus 17/187 (9%) when effective; P = 0.3].


HCAP is associated with worse outcomes than CAP. MDR pathogens were implicated in only a small fraction of HCAP cases. In our study, unlike CAP, non-respect of current HCAP guidelines had no adverse effect on the ultimate outcome. Strategies for the empirical management of HCAP should be tailored to the local epidemiological context.


June 19, 2011 at 6:47 pm Leave a comment

Low Incidence of HIV-1 Superinfection Even After Episodes of Unsafe Sexual Behavior of Homosexual Men in the Amsterdam Cohort Studies on HIV Infection and AIDS.

J Infect Dis. 2011 Jun V.203 N.11 P.1621-8.

Rachinger A, Manyenga P, Burger JA, Derks van de Ven TL, Stolte IG, Prins M, van ‘t Wout AB, Schuitemaker H.

SourceDepartment of Experimental Immunology, Sanquin Research, Landsteiner Laboratory, and Center for Infection and Immunity Amsterdam (CINIMA) at the Academic Medical Center of the University of Amsterdam.



Human immunodeficiency virus type 1 (HIV-1) superinfection is infection of an HIV-1 seropositive individual with another HIV-1 strain. The rate at which HIV-1 superinfection occurs might be influenced by sexual behavior. Superinfection might be detected more often by analyzing longitudinal samples collected from time periods of unsafe sexual behavior.


Envelope C2-C4 and gag sequences were generated from HIV-1 RNA from longitudinal serum samples that were obtained around self-reported sexual risk periods from 15 homosexual therapy-naïve men who participated in the Amsterdam Cohort Studies on HIV Infection and AIDS. Maximum likelihood phylogenetic analysis was used to determine whether HIV-1 superinfection had occurred.


We studied a total of 124 serum samples from 15 patients with a median of 8 samples and of 5.8 person-years of follow-up per patient. Phylogenetic analysis on 907 C2-C4 env and 672 gag sequences revealed no case of HIV-1 superinfection, resulting in a superinfection incidence rate of 0 per 100 person-years [95%CI: 0 – -4.2].


We conclude that HIV-1 superinfection incidence is low in this subgroup of homosexual men who reported unsafe sexual behavior. Additional studies are required to estimate the impact of also other factors, which may determine the risk to acquire HIV-1 superinfection.

Medline abstract

June 19, 2011 at 6:44 pm Leave a comment


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