Archive for March, 2015

A Retrospective Review of the Clinical Experience of Linezolid with or Without Rifampicin in Prosthetic Joint Infections Treated with Debridement and Implant Retention.

Infect Dis Ther. 2014 Aug 20.

Morata L1, Senneville E, Bernard L, Nguyen S, Buzelé R, Druon J, Tornero E, Mensa J, Soriano A.

1Bone and Joint Infection Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer, Hospital Clínic of Barcelona, C/Villarroel 170, 08036, Barcelona, Spain,



Debridement and prosthesis retention, combined with a prolonged antibiotic regimen including rifampicin, is an accepted therapeutic approach when the duration of symptoms is less than 4 weeks and there are no radiological signs of loosening.

The outcome of patients managed with this strategy has been previously assessed in several articles with success rates of 60-90%.

This study aims to review the clinical experience with linezolid in 3 different hospitals from Spain and France in patients with prosthetic joint infection (PJI) managed with debridement, retention of the implant and treated with linezolid with or without rifampicin.


Patients with an acute PJI who underwent open debridement with implant retention treated with linezolid for more than 7 days in 3 hospitals from Barcelona, Tours and Lille between 2005 and 2011 were retrospectively reviewed. Relevant information about demographics, co-morbidity, type of implant, surgical treatment, microorganism isolated, antimicrobial therapy, adverse events (AEs) and outcomes were recorded from patients.


A total of 39 patients were retrospectively reviewed. The mean age (SD) was 70.5 (8.8) years and 9 patients had diabetes mellitus (23%). There were 25 (64%) knee prostheses, 13 (33%) hips and 1 shoulder (3%). The median interquartile range (IQR) days from arthroplasty to infection diagnosis was 17 (19-48) and 33 (85%) cases were diagnosed within the first 60 days. The median (IQR) duration of antibiotic treatment was 70.5 (34-96) days and the median (IQR) number of days on linezolid treatment was 44.5 (30-81). AEs were observed in 15 patients (38%), with gastrointestinal complaints in 8 cases and anemia in 5 being the most frequent. After a median (IQR) follow-up of 2.5 (1.8-3.6) years, there were 11 failures (28%) (8 relapses and 3 new infections). The failure rate was higher in the rifampicin group (36% vs. 18%) mainly due to a higher relapse rate (27% vs. 12%) although differences were not statistically significant.


Management of acute PJIs with debridement and retention of the implant linezolid, with or without rifampicin, is associated with a high remission rate and it is an alternative treatment for infections due to fluoroquinolone and/or rifampicin-resistant staphylococci.


March 29, 2015 at 10:40 am

Updated Recommendations for the Use of Typhoid Vaccine — Advisory Committee on Immunization Practices, United States, 2015

MMWR Weekly March 27, 2015 V.64  N.11 P.305-308

Brendan R. Jackson, MD, Shahed Iqbal, PhD, Barbara Mahon, MD.

1Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC; 2Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Infectious Diseases, CDC (Corresponding author: Brendan R. Jackson,, 404-639-0536)

These revised recommendations of the Advisory Committee on Immunization Practices update recommendations published in MMWR in 1994 (1) and include updated information on the two currently available vaccines and on vaccine safety.

They also include an update on the epidemiology of enteric fever in the United States, focusing on increasing drug resistance in Salmonella enterica serotype Typhi, the cause of typhoid fever, as well as the emergence of Salmonella serotype Paratyphi A, a cause of paratyphoid fever, against which typhoid vaccines offer little or no protection…..


PDF See P.305-308


March 29, 2015 at 10:36 am

Mycoplasma pneumoniae Outbreak in a Long-Term Care Facility — Nebraska, 2014

MMWR Weekly March 27, 2015 V.64  N.11 P.296-299

Deborah L. Hastings, MD, Kari J. Harrington, Preeta K. Kutty, MD, et al.

1Epidemic Intelligence Service, CDC; 2Nebraska Department of Health and Human Services; 3East Central District Health Department, Nebraska; 4National Center for Immunization and Respiratory Diseases, CDC (Corresponding author: Deborah L. Hastings,, 402-471-1376)

On June 20, 2014, a Nebraska long-term care facility notified the East Central District Health Department (ECDHD) and Nebraska Department of Health and Human Services (NDHHS) of an outbreak of respiratory illness characterized by cough and fever in 22 residents and resulting in four deaths during the preceding 2 weeks.

To determine the etiologic agent, identify additional cases, and implement control measures, Nebraska and CDC investigators evaluated the facility’s infection prevention measures and collected nasopharyngeal (NP) and oropharyngeal (OP) swabs or autopsy specimens from patients for real-time polymerase chain reaction (PCR) testing at CDC.

The facility was closed to new admissions until 1 month after the last case, droplet precautions were implemented, ill residents were isolated, and group activities were canceled.

During the outbreak, a total of 55 persons experienced illnesses that met the case definition; 12 were hospitalized, and seven died.

PCR detected Mycoplasma pneumoniae DNA in 40% of specimens. M. pneumoniae should be considered a possible cause of respiratory illness outbreaks in long-term care facilities.

Morbidity and mortality from respiratory disease outbreaks at long-term care facilities might be minimized if facilities monitor for respiratory disease clusters, report outbreaks promptly, prioritize diagnostic testing in outbreak situations, and implement timely and strict infection control measures to halt transmission…..


PDF See P.296-299


March 29, 2015 at 10:33 am

Reassessment of HIV-1 Acute Phase Infectivity: Accounting for Heterogeneity and Study Design with Simulated Cohorts

Plos Medicine MARCH 17, 2015

Steve E. Bellan 1 , Jonathan Dushoff 2, Alison P. Galvani 3-4, Lauren Ancel Meyers5-6

1 Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, Texas,

United States of America,

2 Department of Biology, McMaster University, Hamilton, Ontario, Canada,

3 Yale School of Public Health, Yale University, New Haven, Connecticut, United States of America,

4 Department of Ecology and Evolution, Yale University, New Haven, Connecticut, United States of America, 5 Department of Integrative Biology, The University of Texas at Austin, Austin, Texas, United States of America,

6 The Santa Fe Institute, Santa Fe, New Mexico, United States of America


The infectivity of the HIV-1 acute phase has been directly measured only once, from a retrospectively identified cohort of serodiscordant heterosexual couples in Rakai, Uganda. Analyses of this cohort underlie the widespread view that the acute phase is highly infectious, even more so than would be predicted from its elevated viral load, and that transmission occurring shortly after infection may therefore compromise interventions that rely on diagnosis and treatment, such as antiretroviral treatment as prevention (TasP). Here, we re-estimate the duration and relative infectivity of the acute phase, while accounting for several possible sources of bias in published estimates, including the retrospective cohort exclusion criteria and unmeasured heterogeneity in risk.

Methods and Findings

We estimated acute phase infectivity using two approaches. First, we combined viral load trajectories and viral load-infectivity relationships to estimate infectivity trajectories over the course of infection, under the assumption that elevated acute phase infectivity is caused by elevated viral load alone. Second, we estimated the relative hazard of transmission during the acute phase versus the chronic phase (RHacute) and the acute phase duration (dacute) by fitting a couples transmission model to the Rakai retrospective cohort using approximate Bayesian computation. Our model fit the data well and accounted for characteristics overlooked by previous analyses, including individual heterogeneity in infectiousness and susceptibility and the retrospective cohort’s exclusion of couples that were recorded as serodiscordant only once before being censored by loss to follow-up, couple dissolution, or study termination. Finally, we replicated two highly cited analyses of the Rakai data on simulated data to identify biases underlying the discrepancies between previous estimates and our own.

From the Rakai data, we estimated RHacute = 5.3 (95% credibility interval [95% CrI]: 0.79–57) and dacute = 1.7 mo (95% CrI: 0.55–6.8). The wide credibility intervals reflect an inability to distinguish a long, mildly infectious acute phase from a short, highly infectious acute phase, given the 10-mo Rakai observation intervals. The total additional risk, measured as excess hazard-months attributable to the acute phase (EHMacute) can be estimated more precisely: EHMacute = (RHacute – 1) × dacute, and should be interpreted with respect to the 120 hazard-months generated by a constant untreated chronic phase infectivity over 10 y of infection. From the Rakai data, we estimated that EHMacute = 8.4 (95% CrI: -0.27 to 64). This estimate is considerably lower than previously published estimates, and consistent with our independent estimate from viral load trajectories, 5.6 (95% confidence interval: 3.3–9.1). We found that previous overestimates likely stemmed from failure to account for risk heterogeneity and bias resulting from the retrospective cohort study design.

Our results reflect the interaction between the retrospective cohort exclusion criteria and high (47%) rates of censorship amongst incident serodiscordant couples in the Rakai study due to loss to follow-up, couple dissolution, or study termination. We estimated excess physiological infectivity during the acute phase from couples data, but not the proportion of transmission attributable to the acute phase, which would require data on the broader population’s sexual network structure.


Previous EHMacute estimates relying on the Rakai retrospective cohort data range from 31 to 141. Our results indicate that these are substantial overestimates of HIV-1 acute phase infectivity, biased by unmodeled heterogeneity in transmission rates between couples and by inconsistent censoring. Elevated acute phase infectivity is therefore less likely to undermine TasP interventions than previously thought. Heterogeneity in infectiousness and susceptibility may still play an important role in intervention success and deserves attention in future analyses




March 25, 2015 at 8:32 am

Clinical characteristics and outcomes of prosthetic joint infection caused by small colony variant staphylococci.

MBio. 2014 Sep 30;5(5):e01910-14.

Tande AJ1, Osmon DR2, Greenwood-Quaintance KE3, Mabry TM4, Hanssen AD4, Patel R.


Small colony variants (SCVs) are naturally occurring subpopulations of bacteria.

The clinical characteristics and treatment outcomes of patients with prosthetic joint infection (PJI) caused by staphylococcal SCVs are unknown.

This study was a retrospective series of 113 patients with staphylococcal PJI, with prospective testing of archived sonicate fluid samples.

SCVs were defined using two-investigator review. Treatment failure was defined as

(i) subsequent revision surgery for any reason,

(ii) PJI after the index surgery,

(iii) prosthesis nonreimplantation due to ongoing infection, or

(iv) amputation of the affected limb.

There were 38 subjects (34%) with SCVs and 75 (66%) with only normal-phenotype (NP) bacteria.

Subjects with SCVs were more likely to have been on chronic antimicrobials prior to surgery (P = 0.048), have had prior surgery for PJI (P = 0.03), have had a longer duration of symptoms (P = 0.0003), and have had a longer time since joint implantation (P = 0.007), compared to those with only NP bacteria.

Over a median follow-up of 30.6 months, 9 subjects (24%) with SCVs and 23 (32%) with only NP bacteria experienced treatment failure (P = 0.51).

Subjects infected with Staphylococcus aureus were more likely to fail than were those infected with Staphylococcus epidermidis (hazard ratio [HR], 4.03; 95% confidence interval [CI], 1.80 to 9.04).

While frequently identified in subjects with PJI and associated with several potential predisposing factors, SCVs were not associated with excess treatment failure compared to NP infections in this study, where they were primarily managed with two-stage arthroplasty exchange.


Bacteria with the small colony variant (SCV) phenotype are described in small case series as causing persistent or relapsing infection, but there are insufficient data to suggest that they should be managed differently than infection with normal-phenotype bacteria. In an effort to investigate the clinical importance of this phenotype, we determined whether SCVs were present in biofilms dislodged from the surfaces of arthroplasties of patients with staphylococcal prosthetic joint infection and assessed the clinical outcomes associated with detection of SCVs. We found that prosthetic joint infection caused by SCV staphylococci was associated with a longer duration of symptoms and more prior treatment for infection but not with an increased rate of treatment failure, compared to infection caused by normal-phenotype staphylococci.


March 25, 2015 at 8:26 am

Clindamycin versus trimethoprim-sulfamethoxazole for uncomplicated skin infections.

N Engl J Med 2015 Mar 19, V.372 N.12 P.1093-1103

Loren G. Miller, M.D., M.P.H., Robert S. Daum, M.D., C.M., C. Buddy Creech, M.D., M.P.H., David Young, M.D., Michele D. Downing, R.N., M.S.N., Samantha J. Eells, M.P.H., Stephanie Pettibone, B.S., Rebecca J. Hoagland, M.S., and Henry F. Chambers, M.D. for the DMID 07-0051 Team


Skin and skin-structure infections are common in ambulatory settings. However, the efficacy of various antibiotic regimens in the era of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) is unclear.


We enrolled outpatients with uncomplicated skin infections who had cellulitis, abscesses larger than 5 cm in diameter (smaller for younger children), or both. Patients were enrolled at four study sites. All abscesses underwent incision and drainage. Patients were randomly assigned in a 1:1 ratio to receive either clindamycin or trimethoprim–sulfamethoxazole (TMP-SMX) for 10 days. Patients and investigators were unaware of the treatment assignments and microbiologic test results. The primary outcome was clinical cure 7 to 10 days after the end of treatment.


A total of 524 patients were enrolled (264 in the clindamycin group and 260 in the TMP-SMX group), including 155 children (29.6%). One hundred sixty patients (30.5%) had an abscess, 280 (53.4%) had cellulitis, and 82 (15.6%) had mixed infection, defined as at least one abscess lesion and one cellulitis lesion. S. aureus was isolated from the lesions of 217 patients (41.4%); the isolates in 167 (77.0%) of these patients were MRSA. The proportion of patients cured was similar in the two treatment groups in the intention-to-treat population (80.3% in the clindamycin group and 77.7% in the TMP-SMX group; difference, −2.6 percentage points; 95% confidence interval [CI], −10.2 to 4.9; P=0.52) and in the populations of patients who could be evaluated (466 patients; 89.5% in the clindamycin group and 88.2% in the TMP-SMX group; difference, −1.2 percentage points; 95% CI, −7.6 to 5.1; P=0.77). Cure rates did not differ significantly between the two treatments in the subgroups of children, adults, and patients with abscess versus cellulitis. The proportion of patients with adverse events was similar in the two groups.


We found no significant difference between clindamycin and TMP-SMX, with respect to either efficacy or side-effect profile, for the treatment of uncomplicated skin infections, including both cellulitis and abscesses. (Funded by the National Institute of Allergy and Infectious Diseases and the National Center for Advancing Translational Sciences, National Institutes of Health; number, NCT00730028.)




N Engl J Med 2015 Mar 19 V.372 N.12 P.1164-1165


Choosing an antibiotic for skin infections.

Michael R. Wessels, M.D.

From the Division of Infectious Diseases, Boston Children’s Hospital, and the Department of Pediatrics, Harvard Medical School — both in Boston.

Since the mid-1990s, methicillin-resistant Staphylococcus aureus (MRSA) has become the predominant pathogen responsible for suppurative skin infections (i.e., furuncles, carbuncles, and skin abscesses) in the United States and in many other countries.

Emergency department visits for skin abscesses have increased during this period, as MRSA has become endemic in the community, but a similar increase in visits for cellulitis (i.e., infectious inflammation of the skin without a drainable collection of pus) has not occurred.

The microbiologic characteristics of cellulitis are less well defined because material for culture is not readily available.

Although S. aureus is the organism most frequently isolated from needle aspirates or punch biopsy samples in cellulitis, cultures are negative in more than 70% of such samples, and serologic evidence suggests that Streptococcus pyogenes and other beta-hemolytic streptococci cause most cases….


March 19, 2015 at 8:25 am

Risk of transmission of carbapenem-resistant Enterobacteriaceae and related “superbugs” during gastrointestinal endoscopy.

World J Gastrointest Endosc. 2014 Oct 16;6(10):457-74.

Muscarella LF1.

Author information

1Lawrence F Muscarella, LFM Healthcare Solutions, LLC, Montgomeryville, PA 18936, United States.


To evaluate the risk of transmission of carbapenem-resistant Enterobacteriaceae (CRE) and their related superbugs during gastrointestinal (GI) endoscopy. Reports of outbreaks linked to GI endoscopes contaminated with different types of infectious agents, including CRE and their related superbugs, were reviewed.

Published during the past 30 years, both prior to and since CRE’s emergence, these reports were obtained by searching the peer-reviewed medical literature (via the United States National Library of Medicine’s “MEDLINE” database); the Food and Drug Administration’s Manufacturer and User Facility Device Experience database, or “MAUDE”; and the Internet (via Google’s search engine).

This review focused on an outbreak of CRE in 2013 following the GI endoscopic procedure known as endoscopic retrograde cholangiopancreatography, or ERCP, performed at “Hospital X” located in the suburbs of Chicago (IL; United States).

Part of the largest outbreak of CRE in United States history, the infection and colonization of 10 and 28 of this hospital’s patients, respectively, received considerable media attention and was also investigated by the Centers for Disease Control and Prevention (CDC), which published a report about this outbreak in Morbidity and Mortality Weekly Report (MMWR), in 2014.

This report, along with the results of an independent inspection of Hospital X’s infection control practices following this CRE outbreak, were also reviewed.

While this article focuses primarily on the prevention of transmissions of CRE and their related superbugs in the GI endoscopic setting, some of its discussion and recommendations may also apply to other healthcare settings, to other types of flexible endoscopes, and to other types of transmissible infectious agents.

This review found that GI endoscopy is an important risk factor for the transmission of CRE and their related superbugs, having been recently associated with patient morbidity and mortality following ERCP.

The CDC reported in MMWR that the type of GI endoscope, known as an ERCP endoscope, that Hospital X used to perform ERCP in 2013 on the 38 patients who became infected or colonized with CRE might be particularly challenging to clean and disinfect, because of the complexity of its physical design.

If performed in strict accordance with the endoscope manufacturer’s labeling, supplemented as needed with professional organizations’ published guidelines, however, current practices for reprocessing GI endoscopes, which include high-level disinfection, are reportedly adequate for the prevention of transmission of CRE and their related superbugs.

Several recommendations are provided to prevent CRE transmissions in the healthcare setting. CRE transmissions are not limited to contaminated GI endoscopes and also have been linked to other reusable flexible endoscopic instrumentation, including bronchoscopes and cystoscopes.

In conclusion, contaminated GI endoscopes, particularly those used during ERCP, have been causally linked to outbreaks of CRE and their related superbugs, with associated patient morbidity and mortality. Thorough reprocessing of these complex reusable instruments is necessary to prevent disease transmission and ensure patient safety during GI endoscopy.

Enhanced training and monitoring of reprocessing staffers to verify the proper cleaning and brushing of GI endoscopes, especially the area around, behind and near the forceps elevator located at the distal end of the ERCP endoscope, are recommended. If the ERCP endoscope features a narrow and exposed channel that houses a wire connecting the GI endoscope’s control head to this forceps elevator, then this channel’s complete reprocessing, including its flushing with a detergent using a procedure validated for effectiveness, is also emphasized.



March 18, 2015 at 3:45 pm

Older Posts


March 2015

Posts by Month

Posts by Category