Search

Background: Based on promising results from laboratory studies, we hypothesized that pneumococcal vaccination would protect patients from myocardial infarction., Methods: We conducted a hospital-based case-control study that included patients considered to be at risk of myocardial infarction. We used health databases to obtain hospital diagnoses and vaccination status. We compared patients who had been admitted for treatment of myocardial infarction with patients admitted to a surgical department in the same hospital for a reason other than myocardial infarction between 1997 and 2003., Results: We found a total of 43 209 patients who were at risk; of these, we matched 999 cases and 3996 controls according to age, sex and year of hospital admission. Cases were less likely than controls to have been vaccinated (adjusted odds ratio [OR] 0.53, 95% confidence interval [CI] 0.40-0.70). This putative protective role of the vaccine was not observed for patients who had received the vaccine up to 1 year before myocardial infarction (adjusted OR 0.85, 95% CI 0.54-1.33). In contrast, if vaccination had occurred 2 years or more before the hospital admission, the association was stronger (adjusted OR 0.33, 95% CI 0.20-0.46)., Interpretation: Pneumococcal vaccination was associated with a decrease of more than 50% in the rate myocardial infarction 2 years after exposure. If confirmed, this association should generate interest in exploring the putative mechanisms and may offer another reason to promote pneumococcal vaccination.

Sequencing of the 16S gene or other targets and line probe assay are in wide use for the identification of nontuberculous mycobacteria. We compared in-house and commercial sequencing with 3 sequence databases against high-performance liquid chromatography (HPLC) and line probe assay (HAIN Genotype AS and CM) for the identification of 84 reference, clinical, and unique strains representing 41 species. Consensus of methods was used as reference standard. Sequencing identification was more specific and flexible than HPLC, but it was limited by database content and quality as well as fragment length. No one database satisfied all requirements. In-house sequencing was lower in cost than commercial sequencing or line probe assay.

Purpose of Review: The aim of this paper is to assess the contribution of antiretroviral therapy to cardiovascular disease, by evaluating relevant clinical and surrogate outcome studies., Recent Findings: A large proportion of patients receiving antiretroviral therapy develop insulin resistance and dyslipidemia, particularly if exposed to protease inhibitors. Recent findings from clinical outcome studies suggest that protease inhibitor-based therapy is associated with an increased risk of cardiovascular disease, with a consistent estimated increased risk of 1.16 to 1.17 for each additional year of protease inhibitor exposure. Antiretroviral therapy discontinuation, however, has also been linked with increased risk of cardiovascular disease. There are some data from clinical and surrogate outcome studies, that interventions addressing conventional risk factors and switching antiretroviral therapy may reduce cardiovascular disease risk., Summary: Combination antiretroviral therapy in general, and protease inhibitor-based antiretroviral therapy in particular, is associated with an increased risk of cardiovascular disease. This risk is likely mediated, in part, by changes in blood lipids. The absolute risk of cardiovascular disease for the individual patient depends on his or hers composite risk profile. It is becoming increasingly important to carry out an adequate cardiovascular disease risk assessment in each patient, in order to identify patients in need of specific interventions.

Genital epithelial cells (ECs) are the first line of defense that sexually transmitted viruses encounter. The mechanism of viral pathogenesis in these cells is not well understood. Here, we show that a primary cell culture model from human reproductive tract tissues can be used as a novel ex vivo model in examining the interaction of herpes simplex virus, type 2 (HSV-2), with female genital mucosa. Confluent, polarized primary cultures of human endometrial and cervical ECs were established and shown to be free from any significant contamination of any other cell type. Both endometrial and cervical ECs were found to be highly susceptible to HSV-2 infection. The kinetic of infection was similar to in vivo infection, with the earliest viral shedding seen at 18 h postinfection. Primary EC monolayers could be infected both apically and basolaterally, but preferential viral shedding was seen on the apical side of cells. Following treatment of the monolayers with poly (I:C), an innate immune activator that acts via TLR3, viral shedding was reduced significantly, comparable to levels seen when an antiviral formulation, acyclovir, was used. Treatment of epithelial and stromal co-cultures with estradiol increased HSV-2 infection in endometrial ECs, but viral shedding decreased following treatment with progesterone. To the best of our knowledge, this is the first study that examines the interaction of primary human female genital ECs with HSV-2, using an ex vivo culture model. The results provide valuable information regarding the susceptibility of women's genital ECs to HSV-2 and the ability of innate immunity and hormones to modify this susceptibility.

Background: Staff identification badges are mandatory in all hospitals. The purpose of this study was to assess microbial contamination of identification badges at a Canadian tertiary centre. Risk factors for badge contamination were also investigated., Methods: Badges were cultured from 118 subjects including secretaries, physicians, nurses, and allied health workers. Subjects also completed a demographic questionnaire. Badge contamination was analyzed according to profession, workplace, duration of badge use, presence of a plastic cover, how the badge was worn, and cleaning frequency., Results: 13.6% of the badges were contaminated with significant pathogens. S. aureus was isolated in 6.8% of the badges, gram-negative bacilli in 5.9%. Contamination was highest in nurses (21.4% versus 9.4-14.3% in other professions) and in the ICU (22.6% versus 8.3%-14.3% at other locations). Neither association was statistically significant. Covered and non-covered badges had similar contamination rates (12% and 17.1%) as did badges worn around the neck compared with those worn clipped to clothing (13.0% versus 14.6%). Contamination of recently cleaned badges was not statistically different from those that had not., Conclusion: Identification badges do not appear to be a major reservoir for pathogenic organisms. Badges can, however, harbour disease-causing organisms and should be cleaned regularly.

Infections with Chlamydia trachomatis and Neisseria gonorrhoeae are often asymptomatic. Liquid-based Pap (L-Pap) screening may provide samples for testing by commercial assays. Women attending a health clinic or a street youth clinic had a PreservCyt ThinPrep sample and a cervical swab (CS) collected. The L-Pap sample was tested for cytopathology; then 1 ml was transferred to an L-Pap specimen transfer tube for testing by the Gen-Probe APTIMA assays (APTIMA Combo 2 [AC2], APTIMA C. trachomatis [ACT], and APTIMA N. gonorrhoeae [AGC]). The residual L-Pap sample was tested for C. trachomatis and N. gonorrhoeae using Roche AMPLICOR (AMP) and Becton Dickinson ProbeTec (PT). The CS was tested by AC2. A patient was considered infected if two specimens were positive or if a single specimen was positive in two tests. The prevalence of infection was 10% (29/290) for C. trachomatis and 2.4% (7/290) for N. gonorrhoeae. Most of the positive patients had specimens that were reactive in all assays (20/29 for C. trachomatis; 6/7 for N. gonorrhoeae). Four patients had double infections. The sensitivities and specificities of the various tests for the specimens tested were as follows. For C. trachomatis on L-Pap, sensitivity and specificity were 100 and 98.1%, respectively, for ACT, 93.1 and 98.8% for AC2, 86.2 and 91.2% for AMP, and 72.4 and 92.7% for PT. For N. gonorrhoeae on L-Pap, sensitivity and specificity were 100% for both AGC and AC2, 85.7 and 100% for AMP, and 85.7 and 100% for PT. For AC2 with CSs, sensitivity and specificity were 93.1 and 98.5%, respectively, for C. trachomatis, and both were 100% for N. gonorrhoeae. There were significant differences in sensitivity and specificity (P < 0.001). The APTIMA assays were more sensitive and specific than AMP or PT for detecting women's C. trachomatis and/or N. gonorrhoeae infections by testing ThinPrep samples.

The Digene Hybrid Capture 2 (HC2) assay for high-risk human papillomavirus (HPV) identified 92 (28.7%) infected women by testing 320 SurePath liquid-based Pap samples and a hybrid capture 2 (HC2) sampler collection. HPV positivity was predictive for high-grade lesions. A majority of women had normal cervical readings although 15.8% were HPV-positive. Half of the patients with a reading of atypical squamous cells of undetermined significance (ASCUS) (n=16) were HPV-positive.

It is uncertain whether hospitalization among patients with congestive heart failure (CHF) increases during the influenza season. This retrospective cohort study used influenza surveillance data from the United States (1986-1987 to 1990-1991), clinical information from the Studies of Left Ventricular Dysfunction (SOLVD) database, and daily temperature data from the National Climatic Data Center to assess the effect of influenza season on hospitalizations in this cohort of patients. The overall hospitalization rate was higher during influenza seasons compared to non-influenza seasons [relative risk (RR) 1.08, 95% confidence interval (CI) 1.01-1.16]. Multivariable Cox modelling revealed an adjusted hazard ratio (HR) of 1.11 for hospitalization during the influenza season (95% CI 1.03-1.20, P=0.005). Overall death rates were also higher during influenza seasons than non-influenza seasons (RR 1.09, 95% CI 0.97-1.21), but the corresponding adjusted HR for death was not significant (HR 1.01, 95% CI 0.98-1.24, P=0.11). Patients with CHF have a greater risk of hospitalization during the influenza season than in the non-influenza season, supporting the current belief that patients with CHF should be regarded as a high-risk group.

RIDASCREEN norovirus enzyme immunoassay (EIA) detected 80.3% of norovirus-infected feces samples compared to 60.6% by IDEIA NLV GI/GII from 228 patients with no false positives by either assay. RT-PCR and electron microscopy percent sensitivity and specificity were 98.5, 100 and 36.4 and 96.9, respectively.

Three commercially available real-time reverse transcriptase PCR assays (the Artus RealArt HPA coronavirus LightCycler, the Artus RealArt HPA coronavirus Rotor-Gene, and the EraGen severe acute respiratory syndrome coronavirus POL assay) and three RNA extraction methodologies were evaluated for the detection of severe acute respiratory syndrome coronavirus RNA from 91 stool specimens. The assays' sensitivities were highest (58% to 75%) for specimens obtained 8 to 21 days after symptom onset. The assays were less sensitive when specimens were obtained less than 8 days or more than 21 days after the onset of symptoms. All assays were 100% specific.

Background: To date, no randomized trial to address the use of adjunctive rifampin in addition to metronidazole for the treatment of Clostridium difficile-associated diarrhea has been reported. Rifampin has excellent in vitro activity against C. difficile and penetrates into cellular materials where the organisms may persist., Methods: This was a prospective, randomized, single-blinded study of 39 patients that compared therapy with metronidazole alone versus therapy with metronidazole and rifampin for 10 days to treat laboratory-confirmed primary episode C. difficile-associated diarrhea. Twenty patients were randomly assigned to the metronidazole group, and 19 were randomly assigned to the metronidazole and rifampin group. Data were analyzed by intention-to-treat analysis using the 2-tailed Kaplan-Meier method and the log-rank test., Results: Adjunctive rifampin treatment for 10 days, compared with treatment with metronidazole alone for 10 days, was associated with a similar median time to symptom improvement (9.0 days vs. 6.5 days; P=.74), a similar median time to first relapse (26 days vs. 16 days; P=.23), a similar proportion of patients with relapse by study day 40 (42% vs. 38%; P=1.0), and a similar proportion of patients experiencing nonfatal adverse events (37% vs. 40%; P=.55). There were a significantly higher number of deaths in the metronidazole and rifampin group, compared with the metronidazole group (6 of 19 patients vs. 1 of 20 patients; P=.04), but there were fewer laboratory-confirmed relapses by study day 40 (2 vs. 4; P=.66)., Conclusions: We conclude that there is no role for routine rifampin as an adjunct to treatment with metronidazole for hospitalized patients with C. difficile-associated diarrhea. The cure rates for both treatment groups remain unacceptably low, and better treatments are urgently needed.

The emergence of a novel coronavirus (CoV) as the cause of severe acute respiratory syndrome (SARS) catalyzed the development of rapid diagnostic tests. Stool samples have been shown to be appropriate for diagnostic testing for SARS CoV, although it has been recognized to be a heterogeneous and difficult sample that contains amplification inhibitors. Limited information on the efficiency of extraction methods for the purification and concentration of SARS CoV RNA from stool samples is available. Our study objectives were to determine the optimal extraction method for SARS CoV RNA detection and to examine the effect of increased specimen volume for the detection of SARS CoV RNA in stool specimens. We conducted a multicenter evaluation of four automated and four manual extraction methods using dilutions of viral lysate in replicate mock stool samples, followed by quantitation of SARS CoV RNA using real-time reverse transcriptase PCR. The sensitivities of the manual methods ranged from 50% to 100%, with the Cortex Biochem Magazorb method, a magnetic bead isolation method, allowing detection of all 12 positive samples. The sensitivities of the automated methods ranged from 75% to 100%. The bioMérieux NucliSens automated extractor and miniMag extraction methods each had a sensitivity of 100%. Examination of the copy numbers detected and the generation of 10-fold dilutions of the extracted material indicated that a number of extraction methods retained inhibitory substances that prevented optimal amplification. Increasing the volume of sample input did improve detection. This information could be useful for the extraction of other RNA viruses from stool samples and demonstrates the need to evaluate extraction methods for different specimen types.

Background: Individual markers of inflammation may add incremental predictive value in the context of conventionally available risk factors. We evaluated the ability of 9 inflammatory biomarkers, microalbuminuria, and N-terminal pro-brain natriuretic peptide (Nt-proBNP) to improve cardiovascular risk prediction beyond that obtained from traditional risk factors in a secondary-prevention population., Methods and Results: We measured biomarkers representing the acute-phase reaction (C-reactive protein, fibrinogen, and interleukin-6), proinflammatory pathways (soluble tumor necrosis factor receptor-1 and -2, soluble interleukin-1 receptor antagonist, and interleukin-18), endothelial activation (soluble vascular adhesion molecule-1 and soluble intercellular adhesion molecule-1), Nt-proBNP, and microalbuminuria in 3199 study individuals of the Heart Outcomes Prevention Evaluation (HOPE) Study and assessed their association with risk of myocardial infarction, stroke, or cardiovascular death (primary outcome, n=501) over 4.5 years of follow-up. In a backward Cox regression procedure that included risk factors and biomarkers, Nt-proBNP (hazard ratio [HR] 1.72 per increment SD, 95% CI 1.39 to 2.12; P<0.0001), soluble intercellular adhesion molecule-1 (HR 1.46, 95% CI 1.19 to 1.80; P=0.0003), microalbuminuria (HR 1.55, 95% CI 1.22 to 1.98; P=0.0004), soluble interleukin-1 receptor antagonist (HR 1.30, 95% CI 1.05 to 1.61; P=0.02), and fibrinogen (HR 1.31, 95% CI 1.05 to 1.62; P=0.02) remained significantly related to the primary outcome. Only inclusion of Nt-proBNP provided incremental information above that obtained by models of traditional risk factors., Conclusions: Although levels of various inflammatory biomarkers are significantly related to future cardiovascular risk, their incremental predictive value is modest. A model consisting of simple traditional risk factors and Nt-proBNP provided the best clinical prediction in the secondary-prevention population.

Significantly more epithelial cells were collected by flocked swabs than by rayon swabs in parallel nasopharyngeal and nasal swabs taken from 16 volunteers. Nasopharyngeal sampling of 61 symptomatic patients also yielded more cells by flocked than rayon swabs, providing better clinical specimens for diagnosis.

Background and Objective: To compare use of both a pooled index and area under the curve (AUC) to the standard analysis of a randomized controlled trial of antibiotics for patients with Alzheimer's disease., Methods: Using data from a randomized, placebo-controlled trial of antibiotics for patients with Alzheimer's disease, a pooled index of six outcome measures was constructed. Each change score was standardized by dividing by the standard deviation, and the six standardized change scores were averaged. The Standardized Alzheimer's Disease Assessment Scale cognitive subscale and the pooled index were plotted against time and the AUC was calculated., Results: The AUC analysis of the pooled index showed significant treatment effect over the 12-month period. In contrast, none of the individual measures showed an effect at more than one time point. The AUC analyses of the Standardized Alzheimer's Disease Assessment Scale cognitive subscale, the primary outcome of the trial, showed no significant difference over the entire 12-month period, although the original individual time-point analysis showed a difference at 6 months alone., Conclusion: Pooled indices and AUC analyses may provide important insight into therapeutic effect of agents tested in randomized clinical trials of patients with Alzheimer's disease.

Background: Digital clubbing is a sign of chest disease known since the time of Hippocrates. Its association with tuberculosis (TB) has not been well studied, particularly in Africa where TB is common. The prevalence of clubbing in patients with pulmonary TB and its association with Human Immunodeficiency Virus (HIV), severity of disease, and nutritional status was assessed., Methods: A cross-sectional study was carried out among patients with smear-positive TB recruited consecutively from the medical and TB wards and outpatient clinics at a public hospital in Uganda. The presence of clubbing was assessed by clinical signs and measurement of the ratio of the distal and inter-phalangeal diameters (DPD/IPD) of both index fingers. Clubbing was defined as a ratio > 1.0. Chest radiograph, serum albumin and HIV testing were done., Results: Two hundred patients (82% HIV-infected) participated; 34% had clubbing by clinical criteria whilst 30% had clubbing based on DPD/IPD ratio. Smear grade, extensive or cavitary disease, early versus late HIV disease, and hypoalbuminemia were not associated with clubbing. Clubbing was more common among patients with a lower Karnofsky performance scale score or with prior TB., Conclusion: Clubbing occurs in up to one-third of Ugandan patients with pulmonary TB. Clubbing was not associated with stage of HIV infection, extensive disease or hypoalbuminemia.

The use of new flocked swabs, compared to kit swabs, enhanced the ability of three commercial nucleic acid amplification tests to detect low levels of Chlamydia trachomatis and Neisseria gonorrhoeae nucleic acids when the organisms were diluted in a universal transport medium as mocked specimens.

The clinical sensitivity of nucleic acid amplification tests may be determined by analytical sensitivity and inhibitors in patient samples. We established endpoints for detection of propagated Chlamydia trachomatis L2 434, diluted according to swab and urine protocols for APTIMA Combo 2 (AC2), ProbeTec ET (PT), and Amplicor (AMP) assays. AC2 was 1,000-fold more sensitive than PT and 10-fold more sensitive than AMP on mock swab specimens. For urine, AC2 analytical sensitivity was 100-fold greater than those of the other assays. Spiking an aliquot of each clinical-trial sample from 298 women demonstrated inhibition rates in first-void urine (FVU), cervical swabs (CS), and vaginal swabs (VS) of 12.1%, 12.8%, and 10.4% for AMP; 27.2%, 2%, and 2%, for PT; and 0.3%, 1.7%, and 1.3% for AC2. Inhibition of our C. trachomatis spike and the PT or AMP amplification controls from the manufacturers showed less than 50% correlation. Using an infected-patient reference standard (a specimen positive in at least two tests or a single test positive in two of three samples) in AC2, the VS identified 68/69 (98.6%) infected women compared to CS (89.9%) or FVU (81.2%). Significantly fewer women were identified by PT (65.2%, 63.8%, and 66.7%) or AMP (65.2%, 59.4%, and 56.5%) with the three specimens. By individual specimen type, AC2 confirmed virtually all PT- and AMP-positive specimens, but rates of AC2 confirmation by AMP or PT ranged from 62.9 to 80.3%. The AC2 test identified significantly more women infected with C. trachomatis (P = 0.001). Vaginal swabs appear to be the specimen of choice for screening.

Background: Chronic inflammation appears to play a role in the pathogenesis of vascular dementia. Given the association between Chlamydia pneumoniae and stroke, the possibility exists that previous exposure to C. pneumoniae may play a role in vascular dementia. The objective of this study was to determine if there was an association between serological evidence of C. pneumoniae infection or inflammatory markers with vascular dementia., Methods: 28 case-patients with vascular dementia at a geriatric clinic and 24 caregiver-controls were tested for C. pneumoniae IgG and IgA antibodies. The association between vascular dementia and C. pneumoniae titres as well as inflammatory markers was estimated by using both conditional logistic regression and stratified logistic regression., Results: When matched cases were compared to controls, there was no significant difference in elevated C. pneumoniae specific IgG antibodies (titre >or= 1:32), odds ratio [OR] 1.3 (95% confidence intervals [CI] 0.3 to 6.0), p = 0.71, or in elevated C. pneumoniae specific IgA antibodies (titre >or= 1:16), OR 2.0 (95%CI 0.5 to 8.0), p = 0.33 indicative of past or persistent C. pneumoniae infection. Similarly, no difference in high IgG or IgA antibody levels (IgG titre >or= 1:512 or IgA titre >or= 1:64) between the two groups, indicative of recent C. pneumoniae infection, was found, OR 0.4 (95%CI 0.1 to 2.1), p = 0.27. For C-reactive protein (CRP), the mean difference between 18 matched pairs (case - control) was - 3.33 mg/L. There was no significant difference between cases and controls when comparing log transformed values, OR 0.03 (95%CI 0.00 to 2.89), p = 0.13 or comparing CRP values above or below the median, OR 0.8 (95%CI 0.2 to 3.4), p = 0.71. For fibrinogen, the mean difference between pairs (case - control) was -0.07 g/L. There was no statistical difference between cases and controls when comparing log transformed values, OR 0.6 (95%CI 0.0 to 31.2), p = 0.79 or between fibrinogen values above and below the median, OR = 0.5 (95%CI 0.1 to 2.0), p = 0.50., Conclusion: We found no evidence for a significant association between C. pneumoniae infection, inflammatory markers such as CRP and fibrinogen, and vascular dementia.

We evaluated seven reverse transcription-PCR (RT-PCR) assays, including six in-house assays and one commercial assay for the detection of severe acute respiratory syndrome coronavirus (SARS-CoV) RNA in clinical specimens. RT-PCR assays targeted different genomic regions and included three conventional assays (one nested and two non-nested) run on a conventional heat block and four real-time assays performed in a LightCycler (LC; Roche Diagnostics). All in-house assays were optimized for assay parameters, including MgCl2, primer, and probe concentrations. The commercial assay was the RealArt HPA CoV RT-PCR assay (Artus), which was run in the LC. Testing serial dilutions of cultured SARS-CoV showed that the analytical sensitivity of the assays ranged from 10(-8) to 10(-6), corresponding to 1 and 100 copies of viral RNA, respectively. Significant differences in analytical sensitivities were observed between assays (P < 0.01, probit regression analysis for 50% sensitivity levels for the top two assays versus the others). Testing 68 clinical specimens (including 17 respiratory tract specimens, 29 urine samples, and 22 stools or rectal swabs) demonstrated that six of the seven assays detected at least 17 of 18 positives (defined as positive in at least two assays), and two of the assays had a sensitivity of 100%. There were no significant differences in sensitivity between the assays (P = 0.5 [Cochrance Q test, least sensitive 15 of 18 versus 18 of 18]). The specificities of the assays ranged from 94.0 to 100% without significant differences (P = 0.25 to 0.5 [McNemar test]). The reagent and technologist cost of performing the in-house PCR assays ranged from $5.46 to $9.81 Canadian dollars (CDN) per test. The commercial assay cost was considerably higher at $40.37 per test. The results demonstrated good performance for all assays, providing laboratories that need to do SARS RNA testing with a choice of assay formats.

Objectives: To assess whether doxycycline and rifampin have a therapeutic role in patients with Alzheimer's disease (AD)., Design: Randomized, triple-blind, controlled trial., Setting: Three tertiary care and two community geriatric clinics in Canada., Participants: One hundred one patients with probable AD and mild to moderate dementia., Intervention: Oral daily doses of doxycycline 200 mg and rifampin 300 mg for 3 months., Measurements: The primary outcome was a change in Standardized Alzheimer's Disease Assessment Scale cognitive subscale (SADAScog) at 6 months. Secondary outcomes were changes in the SADAScog at 12 months and tests of dysfunctional behavior, depression, and functional status., Results: There was significantly less decline in the SADAScog score at 6 months in the antibiotic group than in the placebo group, (-2.75 points, 95% confidence interval (CI)=-5.28 to -0.22, P=.034). At 12 months, the difference between groups in the SADAScog was -4.31 points (95% CI=-9.17-0.56, P=.079). The antibiotic group showed significantly less dysfunctional behavior at 3 months. There was no significant difference in adverse events between groups (P=.34). There were no differences in Chlamydia pneumoniae detection using polymerase chain reaction or antibodies (immunoglobulin (Ig)G or IgA) between groups., Conclusion: Therapy with doxycycline and rifampin may have a therapeutic role in patients with mild to moderate AD. The mechanism is unlikely to be due to their effect on C. pneumoniae. More research is needed to investigate these agents.

Background: An outbreak of severe acute respiratory syndrome (SARS) began in Canada in February 2003. The initial diagnosis of SARS was based on clinical and epidemiological criteria. During the outbreak, molecular and serologic tests for the SARS-associated coronavirus (SARS-CoV) became available. However, without a "gold standard," it was impossible to determine the usefulness of these tests. We describe how these tests were used during the first phase of the SARS outbreak in Toronto and offer some recommendations that may be useful if SARS returns., Methods: We examined the results of all diagnostic laboratory tests used in 117 patients admitted to hospitals in Toronto who met the Health Canada criteria for suspect or probable SARS. Focusing on tests for SARS-CoV, we attempted to determine the optimal specimen types and timing of specimen collection., Results: Diagnostic test results for SARS-CoV were available for 110 of the 117 patients. SARS-CoV was detected by means of reverse-transcriptase polymerase chain reaction (RT-PCR) in at least one specimen in 59 (54.1%) of 109 patients. Serologic test results of convalescent samples were positive in 50 (96.2%) of 52 patients for whom paired serum samples were collected during the acute and convalescent phases of the illness. Of the 110 patients, 78 (70.9%) had specimens that tested positive by means of RT-PCR, serologic testing or both methods. The proportion of RT-PCR test results that were positive was similar between patients who met the criteria for suspect SARS (50.8%, 95% confidence interval [CI] 38.4%-63.2%) and those who met the criteria for probable SARS (58.0%, 95% CI 44.2%-70.7%). SARS-CoV was detected in nasopharyngeal swabs in 33 (32.4%) of 102 patients, in stool specimens in 19 (63.3%) of 30 patients, and in specimens from the lower respiratory tract in 10 (58.8%) of 17 patients., Interpretation: These findings suggest that the rapid diagnostic tests in use at the time of the initial outbreak lack sufficient sensitivity to be used clinically to rule out SARS. As tests for SARS-CoV continue to be optimized, evaluation of the clinical presentation and elucidation of a contact history must remain the cornerstone of SARS diagnosis. In patients with SARS, specimens taken from the lower respiratory tract and stool samples test positive by means of RT-PCR more often than do samples taken from other areas.

Background: Cellular antioxidant enzymes such as glutathione peroxidase 1 and superoxide dismutase have a central role in the control of reactive oxygen species. In vitro data and studies in animal models suggest that these enzymes may protect against atherosclerosis, but little is known about their relevance to human disease., Methods: We conducted a prospective study among 636 patients with suspected coronary artery disease, with a median follow-up period of 4.7 years (maximum, 5.4) to assess the risk of cardiovascular events associated with base-line erythrocyte glutathione peroxidase 1 and superoxide dismutase activity., Results: Glutathione peroxidase 1 activity was among the strongest univariate predictors of the risk of cardiovascular events, whereas superoxide dismutase activity had no association with risk. The risk of cardiovascular events was inversely associated with increasing quartiles of glutathione peroxidase 1 activity (P for trend <0.001); patients in the highest quartile of glutathione peroxidase 1 activity had a hazard ratio of 0.29 (95 percent confidence interval, 0.15 to 0.58; P<0.001), as compared with those in the lowest quartile. Glutathione peroxidase 1 activity was affected by sex and smoking status but retained its predictive power in these subgroups. After adjustment for these and other cardiovascular risk factors, the inverse association between glutathione peroxidase 1 activity and cardiovascular events remained nearly unchanged., Conclusions: In patients with coronary artery disease, a low level of activity of red-cell glutathione peroxidase 1 is independently associated with an increased risk of cardiovascular events. Glutathione peroxidase 1 activity may have prognostic value in addition to that of traditional risk factors. Furthermore, increasing glutathione peroxidase 1 activity might lower the risk of cardiovascular events., (Copyright 2003 Massachusetts Medical Society)

Background: Matrix metalloproteinase (MMP)-9 secretion by macrophages and other inflammatory cells accelerates atherosclerotic progression and destabilizes vulnerable plaque in animal models. However, epidemiological data evaluating the prognostic impact of circulating concentrations and functional genetic variations of MMP-9 are lacking., Methods and Results: In a prospective study of 1127 patients with documented coronary artery disease, we measured baseline plasma MMP-9 levels and determined the MMP-9/C-1562T and MMP-9/R279Q genotypes. During the follow-up period (mean of 4.1 years), 97 patients died from cardiovascular (CV) causes. Median concentrations of MMP-9 were significantly higher among patients who experienced a fatal CV event than among those who did not (62.2 versus 47.8 ng/mL; P<0.0001). The crude hazard risk ratio of CV death associated with increasing quartiles of MMP-9 was 1.4 (95% CI, 1.2 to 1.8; P<0.0001), and after adjustment for clinical and therapeutic confounders, it was 1.3 (95% CI, 1.1 to 1.6; P=0.005). Additional adjustment for highly sensitive CRP, interleukin-6, fibrinogen, and interleukin-18 revealed a hazard risk ratio to 1.2 (95% CI, 0.9 to 1.6; P=0.15). The T allele of the C-1562T polymorphism was associated with increased MMP-9 levels in a fairly codominant fashion (P=0.004). Although none of the polymorphisms was significantly related with future CV death, there was a significant association (P=0.02) between the R279Q polymorphism and CV events in patients with stable angina., Conclusions: Plasma MMP-9 concentration was identified as a novel predictor of CV mortality in patients with coronary artery disease. Whether it provides independent prognostic information compared with other inflammatory markers will have to be additionally assessed.

Background: Influenza is a common viral respiratory infection that is associated with significant morbidity. Oseltamivir (Tamiflu) is a neuraminidase inhibitor-a new class of antiviral treatment for influenza where efficacy and safety has been established but cost-effectiveness is unknown., Methods: A decision analytic model was used to estimate the costs and effectiveness of two treatment scenarios for empiric management of otherwise healthy nonelderly patients, presenting with influenza-like illness (ILI) to primary care physicians in Canada: 1) where oseltamivir is reimbursed and on formulary for prescription; and 2) where oseltamivir is not on formulary. Outcomes are influenza-days averted and quality-adjusted life-years (QALYs) gained. Effectiveness, utility, and pneumonia complication risk estimates are by pooled analysis of patient-level data from four clinical trials. Unit cost information (Canadian dollars) was obtained from published sources in Ontario. Probabilistic sensitivity analysis was conducted using Monte Carlo simulation., Results: Of 2288 patients randomized, influenza was confirmed in 1575 (69%) and oseltamivir treatment reduced the mean time to symptom alleviation by 1.08 days (95% confidence interval CI] 0.58-1.59). Infected patients treated with oseltamivir had higher utility scores (quality of life) than placebo patients over the 7 days of follow-up (P <.05). Cost per influenza-day averted with oseltamivir on formulary is 49 US dollars (95% CI 31-107) and the cost per QALY is 57,863 US dollars (95% CI 48,919- 70,149 US dollars). Results are sensitive to the percentage of patients presenting to their physician beyond 48 hours from symptom onset who get oseltamivir and the prevalence of influenza among patients presenting with ILI., Conclusions: Oseltamivir for treatment of patients with ILI is potentially cost-effective if clinical diagnostic specificity for influenza observed in clinical trials is applicable to routine practice. More population-based information on the prevalence of influenza among early (<48 hours) presenters with ILI would be valuable.

Background: Limited prospective epidemiological data are available on the relation between exposure to Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus (CMV), and hepatitis A virus (HAV), individually or as a total pathogen score, and human cardiovascular (CV) disease., Methods and Results: We analyzed enrollment sera from 3168 Canadian patients in the Heart Outcomes Prevention Evaluation (HOPE) study for antibodies to C pneumoniae, H pylori, CMV, and HAV and measured the relation between serostatus and 494 adjudicated trial outcomes of myocardial infarction, stroke, or CV death over 4.5 years of follow-up. CV events were associated with CMV serostatus (covariate-adjusted hazard ratio [HR], 1.24; 95% CI, 1.01, 1.53). Neither C pneumoniae IgG (adjusted HR, 0.87; 95% CI, 0.68, 1.10), C pneumonia IgA (adjusted HR, 1.10; 95% CI, 0.90, 1.34), H pylori IgG (HR, 0.99; 95% CI, 0.82, 1.19), nor HAV IgG (HR, 1.01; 95% CI, 0.83, 1.24) predicted CV events. Total pathogen score was associated with CV events (adjusted HR for 4 versus 1 or 0=1.41; 95% CI, 1.02, 1.96)., Conclusions: Exposure to CMV but not to C pneumoniae, H pylori, or HAV was associated with a slight excess risk of subsequent myocardial infarction, stroke, or CV death in HOPE study patients, and total pathogen score based on these infections predicted a small increased hazard of CV events.

Background: Several recent studies have indicated an association between key inflammatory mediators and atherosclerotic diseases. We evaluated whether high levels of antibodies against heat shock proteins and cholesterol (ACHA) predicted cardiovascular (CV) events., Methods and Results: We used blood samples from the Heart Outcomes Prevention Evaluation (HOPE) study to conduct a nested case-control study of 386 cases with CV events and 386 age- and sex-matched HOPE study controls without events. We explored the relationship between anti-hsp antibodies, ACHA, and subsequent outcomes (incident myocardial infarction, stroke, or CV death) during a mean follow-up of 4.5 years using conditional logistic regression. High levels of anti-hsp65 antibodies (> or =90th percentile) predicted CV events (OR, 2.1; 95% CI, 1.2 to 3.9, P=0.01). Anti-hsp60 antibodies did not predict any event type, whereas incident stroke developed significantly less frequently in patients with high ACHA levels. Anti-hsp antibodies and ACHA did not correlate with inflammatory (fibrinogen, C-reactive protein, interleukin-6, intracellular adhesion molecule-1) or infectious markers (C pneumoniae or cytomegalovirus antibodies). Anti-hsp65 antibodies (> or =90th percentile) and fibrinogen (highest tertile) had a strong joint effect: patients with high concentrations of both had more CV events (OR, 5.5; 95% CI, 1.8 to 17.5, P=0.004) than patients with low levels of both. A similar joint effect (OR, 2.7; 95% CI, 1.3 to 5.7, P=0.01) was found for high levels of anti-hsp65 and presence of cytomegalovirus antibodies., Conclusions: Serum antibodies to hsp65 were associated with subsequent CV events in this study of high-risk patients, independent of conventional cardiovascular risk factors and other inflammatory markers.

Background: Chlamydia pneumoniae antigens, nucleic acids, or intact organisms have been detected in human atheroma. However, the presence of antibody does not predict subsequent cardiovascular (CV) events. We performed a systematic review to determine whether the detection of C. pneumoniae DNA in peripheral blood mononuclear cells (PBMC) was associated with CV disease., Methods: We sought studies of C. pneumoniae DNA detection in PBMC by polymerase chain reaction (PCR) among patients with CV disease or other clinical conditions. We pooled studies in which CV patients were compared with non-diseased controls. We analyzed differences between studies by meta-regression, to determine which epidemiological and technical characteristics were associated with higher prevalence., Results: Eighteen relevant studies were identified. In nine CV studies with control subjects, the prevalence of circulating C. pneumoniae DNA was 252 of 1763 (14.3%) CV patients and 74 of 874 (8.5%) controls, for a pooled odds ratio of 2.03 (95% CI: 1.34, 3.08, P < 0.001). Prevalence was not adjusted for CV risk factors. Current smoking status, season, and age were associated with C. pneumoniae DNA detection. High prevalence (>40%) was found in patients with cardiac, vascular, chronic respiratory, or renal disease, and in blood donors. Substantial differences between studies were identified in methods of sampling, extraction, and PCR targets., Conclusions: C. pneumoniae DNA detection was associated with CV disease in unadjusted case-control studies. However, adjustment for potentially confounding measures such as smoking or season, and standardization of laboratory methods, are needed to confirm this association.

Background: The prevalence and role of Chlamydia pneumoniae in chronic obstructive pulmonary disease (COPD) remain unclear, and molecular methods of detection may help clarify this relationship., Methods: Consecutive clinically stable patients with smoking-related COPD attending a tertiary care outpatient clinic were enrolled in this cross-sectional study. Peripheral blood mononuclear cells were obtained from 100 patients, and induced sputum was obtained in 62 patients. C. pneumoniae DNA was detected in blood or sputum by nested polymerase chain reaction (PCR)., Results: Patients had mean age (standard deviation) of 65.8 (10.7) years, mean forced expiratory volume in one second (SD) of 1.34 (0.61) L, and 61 (61.0%) were male. C. pneumoniae nucleic acids were detected in 27 (27.0%) patients. Among 62 patients with both blood and sputum available, blood specimens were superior to induced sputum for detection of C. pneumoniae DNA (21 versus 7 detected, P=0.003). Current smoking (odds ratio [OR]=2.6, 95 % confidence interval [CI]: 1.1, 6.6, P=0.04), season (November to April) (OR=3.6, 95% CI: 1.4, 9.2, P=0.007), and chronic sputum production (OR=6.4, 95% CI: 1.8, 23.2, P=0.005) were associated with detection of C. pneumoniae DNA., Conclusions: C. pneumoniae DNA prevalence was higher among current smokers, and during winter/spring months. Prospective molecular studies are needed to examine the role of C. pneumoniae detection in COPD disease symptoms and progression.

In a multicenter comparison of PCR assays utilizing 120 quantitated samples of 16 Chlamydia pneumoniae isolates, an LCx research-use-only (RUO) PCR developed by Abbott Laboratories demonstrated 100% sensitivity on 48 samples with >1 copy of DNA per microl of specimen. The sensitivities of five in-house PCR assays ranged from 54 to 94% for the same samples. All six assays showed decreased sensitivities as the DNA copy numbers of the samples decreased. Overall, sensitivities ranged from 68% for the LCx PCR assay to 29% for one of the in-house tests. The LCx RUO PCR and three of the five in-house PCR tests reported no false positives with the 24 negative samples. Increasing the number of replicates tested increased the sensitivities of all of the assays, including the LCx PCR. The LCx RUO assay showed high reproducibility for a single technologist and between technologists, with a kappa agreement of 0.77. The within-center agreements of the five in-house PCR tests varied from 0.19 to 0.74 on two challenges of 60 specimens 1 month apart. The LCx C. pneumoniae RUO PCR shows excellent potential for use in clinical studies, which could enable standardization of results in the field.

Objective: To determine whether long term doxycycline improves symptoms in patients with chronic seronegative or reactive arthritis., Methods: A randomised, triple blind, controlled clinical trial of three months' treatment with doxycycline or placebo of patients with chronic reactive or seronegative arthritis was conducted. The primary study end points were three month pain and functional status measured by a self administered Arthritis Impact Measurement Scales version 2 (AIMS2) quality of life questionnaire. Secondary end points were pain and functional status at 6-12 months, three month rheumatologist assessed joint count, pain, and arthritis activity, and treatment efficacy in those with previous exposure to chlamydia., Results: Of 60 patients randomly allocated to receive doxycycline or placebo, results from 37 were evaluable at three months. Groups were well balanced for major prognostic variables. Doxycycline had no detectable effect at three months on pain change scores (mean difference 1.5, 95% CI -1.2 to 4.2, p=0.25) or composite functional change scores (mean difference 0.8, 95% CI -5.6 to 7.1, p=0.81). Furthermore, there were no differences in secondary study end points, and no apparent treatment effect in patients with previous chlamydia infection., Conclusion: Three months' treatment with doxycycline did not improve pain or functional status in patients with chronic reactive or seronegative arthritis.

Nucleic acid amplification of clinical specimens with low target concentration has variable sensitivity. We examined whether testing multiple aliquots of extracted DNA increased the sensitivity and reproducibility of Chlamydia pneumoniae detection by PCR. Nested and non-nested C. pneumoniae PCR assays were compared using 10 replicates of 16 serial dilutions of C. pneumoniae ATCC VR-1310. The proportion positive versus the C. pneumoniae concentration was modeled by probit regression analysis. To validate the model, 10 replicates of 26 previously positive patient specimens of peripheral blood mononuclear cells (PBMC), sputum, or nasopharyngeal swabs (NPS) were tested. The proportion of replicates that were positive varied with the concentration of C. pneumoniae in the sample. At concentrations above 5 infection-forming units (IFU)/ml, both nested and non-nested PCR assay sensitivities were 90% or greater. The nested PCR was more sensitive (median detection, 0.35 versus 0.61 IFU/ml; relative median detection, 0.58; 95% confidence interval, 0.31 to 0.99; P = 0.04). In clinical specimens, replicate PCR detected 15 of 26 (nested) versus 1 of 26 (non-nested, P < 0.001). For PBMC specimens, testing 1, 3, or 5 replicates detected 3, 5, or 9 of 10 positive specimens, respectively. Median C. pneumoniae concentrations were estimated at 0.07 IFU/ml for PBMC and at <0.03 IFU/ml for NPS specimens. We conclude that performing 5 or 10 replicates considerably increased the sensitivity and reproducibility of C. pneumoniae PCR and enabled quantitation for clinical specimens. Due to sampling variability, PCR tests done without replication may miss a large proportion of positive specimens, particularly for specimens with small amounts of target C. pneumoniae DNA present.

Objective: Previous exposures to Chlamydia pneumoniae (CP), Helicobacter pylori (HP) or cytomegalovirus (CMV) have been associated with atherosclerotic heart disease. These associations were studied in Canadian patients, and the exposure to five infections measured., Design: Case-control study., Setting: In the coronary care units (Hamilton General site, Henderson General site, McMaster University Medical Centre site of the Hamilton Health Sciences Corporation and St Joseph's Hospital) and from the regional angiography suite (Hamilton General site), Hamilton, Ontario., Patients and Methods: One hundred seven consecutive patients presenting with myocardial infarction or unstable angina (coronary care unit patients), or with previous angina or myocardial infarction (angiography suite patients), were compared with 107 family practice or outpatient clinic control subjects., Interventions: Cardiovascular risk factors were measured, as was serology for CP, HP, CMV, adenovirus and hepatitis A virus. Statistical analysis was by logistic regression, adjusted for age and sex., Results: Exposure to CP was more frequent in patients than in control subjects (85.4% versus 70.3%, adjusted odds ratio [OR] 2.3, 95% CI 1.1 to 5.1, P=0.03). Dividing CP immunoglobulin G absorbance into quarters, with the lowest quarter as the reference group, the adjusted ORs were 2.8, 3.0 and 4.3, respectively, for the second, third and fourth quarters (P=0.001 for trend). The seroprevalences of HP (61.7%), CMV (64.0%), adenovirus (75.6%) and hepatitis A virus (59.2%) were high, with no association with disease., Conclusions: An association was found between heart disease and previous exposure to CP, with a stepwise increase in ORs at higher antibody levels, whereas no association was found with HP, CMV or other infections. A prospective validation of this association is needed.

Peripheral blood mononuclear cells from 208 consecutive patients undergoing elective coronary angiography or angioplasty were collected before, immediately after, and 4 h after the procedure. Nucleic acids of Chlamydia pneumoniae and of cytomegalovirus (CMV) were detected by PCR and confirmed by hybridization. Circulating C. pneumoniae DNA was identified in 24 patients (11.5%) and was associated with current smoking (odds ratio [OR] = 4.5, 95% confidence interval [CI] = 1.6 to 12.2, P = 0.004) but not with arterial narrowing on coronary angiogram or with serological results positive for C. pneumoniae. Circulating CMV DNA was identified in 36 patients (17.3%) and was associated with anti-CMV immunoglobulin G (OR = 2.7, 95% CI = 1.2 to 6.3, P = 0.02) but not with angiographic arterial narrowing or with the need for revascularization. Neither C. pneumoniae nor CMV DNA detection increased after angioplasty, a procedure in which endothelium is disrupted. Larger prospective studies are needed to determine the prognostic significance of DNA detection.

Systematic reviews and meta-analyses provide the highest level of evidence to guide clinical decisions and inform practice guidelines. Publication bias results from the selective publication of studies based on the direction and magnitude of their results--studies without statistical significance (negative studies) are less likely to be published. Bias results from pooling the results from published studies alone leading to overestimation of the effectiveness of the intervention. In this review we define publication bias, how it affects the results of systematic reviews, how it can be detected and minimized, and how it can be prevented.

Chlamydia pneumoniae has been associated with atherosclerosis and coronary artery disease (CAD), and its DNA has been detected in atheromatous lesions of the aorta, carotid, and coronary arteries by a variety of PCR assays. The objective of this study was to compare the performances of five published PCR assays in the detection of C. pneumoniae in peripheral blood mononuclear cells (PBMCs) from patients with coronary artery disease. The assays included two conventional PCRs, one targeting a cloned PstI fragment and one targeting the 16S rRNA gene; two nested PCRs, one targeting the 16S rRNA gene and one targeting ompA; and a touchdown enzyme time release (TETR) PCR, targeting the 16S rRNA gene. All PCRs had similar analytical sensitivities and detected a minimum of 0.005 inclusion-forming units (IFU) of C. pneumoniae; the ompA nested PCR and the TETR PCR were slightly more sensitive and detected 0.001 IFU. Assay reproducibility was examined by testing 10 replicates of C. pneumoniae DNA by each assay. All five assays showed excellent reproducibility at high levels of DNA, with scores of 10 out of 10 for 0.01 IFU, but exhibited decreased reproducibility for smaller numbers of C. pneumoniae IFU for all tests. Pairwise comparison of test results indicated that there was a significant difference between tests (Cochran Q = 32.0, P<0.001), with the PstI fragment (P<0.001) and 16S rRNA (P = 0.002) assays having lower reproducibility than the nested ompA and TETR assays. To further analyze assay sensitivity, C. pneumoniae-infected U-937 mononuclear cells were added to whole blood, and extracted mononuclear-cell DNA was tested by each assay. All five assays showed similar sensitivities, detecting 15 infected cells; three assays detected 3 infected cells, while all assays were negative at the next dilution (1.5 infected cells). A striking difference in performance of the five assays was seen, however, when PBMCs from CAD patients were tested for C. pneumoniae DNA. The ompA nested PCR detected C. pneumoniae DNA in 11 of 148 (7.4%) specimens, the 16S rRNA nested PCR detected 2 positives among the 148 specimens (1.4%) (P<0.001), and the other 3 assays detected no positive specimens (P<0.001, compared with the ompA assay). These results indicate that analytical sensitivity alone does not predict the ability of an assay to detect C. pneumoniae in whole-blood-derived PBMCs. Before standardized assays can be used in wide-scale epidemiological studies, further characterization of these assays will be required to improve our understanding of their performance in the detection of C. pneumoniae in clinical material.

A prospective blinded study was conducted to determine whether immunological differences exist between patients receiving potent antiretroviral therapy who are able to achieve and maintain an undetectable virus load (<50 copies/mL) and those who are not. Eleven patients receiving protease inhibitor-containing antiretroviral therapy were studied for 1 year. After analysis of all baseline samples, patient virus load was disclosed, and patients were classified as suppressors (those who maintained undetectable virus load for 1 year) and nonsuppressors. Baseline virus load and CD4+ T cell count did not differ significantly between the 2 groups. Levels of RANTES production by CD4+ and CD8+ T cells and CD8-mediated inhibition of human immunodeficiency virus type 1 gene expression before initiation of antiretroviral therapy were significantly associated with an undetectable virus load maintained for 1 year (P<.05). Thus, a functionally intact T cell-mediated immune system at the time of initiation of potent antiretroviral therapy may predict long-term virus suppression.

Objective: We compared the reproducibility and accuracy of conventional clinical examination of the diabetic foot to monofilament examination. We also sought to simplify the monofilament examination by reducing it to fewer touch points., Methods: In a cross-sectional study at 10 centers in the United States, Canada, and Switzerland, general internists and residents performed a structured history and physical examination for neuropathy on the feet of diabetic patients. Independent examination by two observers included monofilament sensation, pinprick, vibration, position sense, and ankle reflexes., Main Results: A total of 304 patients were examined by at least one practitioner, and 200 received duplicate examinations. Monofilament examination and ankle reflexes had the best reproducibility, with moderate agreement (kappa = 0.59); pinprick, position, and vibration sense had fair agreement (kappa = 0.28-0.36). No component of the history or physical examination, singly or in aggregate, was both sensitive and specific for identifying a patient with an abnormal monofilament examination. A simplified monofilament examination using only 4 sites per foot (total 8 sites) detected 90% of patients with an abnormal 16-site monofilament evaluation., Conclusions: Conventional clinical examination had low reproducibility and correlated poorly with monofilament examination for the identification of the at-risk patient. The Semmes-Weinstein monofilament examination, a reproducible, valid, and generalizable test of foot sensation, is recommended as the screening procedure of choice for examining diabetic feet.

Objectives: To review the literature and develop evidence-based guidelines for the use of the antibiotic clindamycin., Data Sources: A search of the MEDLINE database for randomized clinical trials, cohort studies and review articles that examine the therapeutic use or potential adverse effects of clindamycin was undertaken for the years 1966 to 1996. In addition, relevant citations obtained from the references cited in the identified reviews, book chapters and antibiotic guidelines were included., Data Extraction: Selected articles examining the indications for or adverse effects from the prophylactic or therapeutic use of clindamycin were selected. A level of evidence was assigned to the indication according to published criteria., Data Synthesis and Conclusions: Randomized clinical trials (level 1 evidence) support the use of clindamycin in a number of common conditions, including preoperative prophylaxis, intra-abdominal infections, recurrent group A streptococcal pharyngitis, Chlamydia trachomatis cervicitis and anaerobic lung infections. Cohort studies (level 2 evidence) support the use of clindamycin for bone and soft tissue infections. Expert opinion (level 3 evidence) supports the use of clindamycin for invasive group A streptococcal infection and the treatment of diabetic foot infections. Clindamycin's disadvantages are its high cost, the common occurrence of rash and the predisposition of patients taking clindamycin to Clostridium difficile-associated colitis. Based on cohort studies, the risk of severe diarrhea in out-patients is as low as one per 1000, but the risk of in-patients acquiring C difficile colonization may be as high as 30%.