Antimicrobial resistance and infection control, 2015
Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is associated with inc... more Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is associated with increased infection risk, yet colonization and infection isolates are rarely compared within the same study. The objectives of this study were to compare colonization and infection isolates from a Veterans Administration hospital in Iowa, and to determine the prevalence of livestock-associated MRSA (LA-MRSA) colonization and infection in a state with high livestock density. All patients with available MRSA isolates collected through routine nasal screening (73%; n = 397) and from infections (27%; n = 148) between December 2010 and August 2012 were included and tested for spa type and presence of PVL and mecA genes. Clinical isolates were tested for antibiotic resistance patterns. Paired colonization and infection isolates were compared for genetic and phenotypic congruity. The most common spa types were t002 (and other CC5-associated strains; 65%) and t008 (and other CC8-associated strains;...
Background
Methicillin-resistant S. aureus (MRSA) pneumonia is associated with poor clinical outc... more Background Methicillin-resistant S. aureus (MRSA) pneumonia is associated with poor clinical outcomes. This study examined the association between microbial characteristics and poor outcomes among patients with methicillin-resistant Staphylococcus aureus pneumonia.
Findings This retrospective cohort study included 75 patients with MRSA pneumonia who were admitted to two large tertiary care medical centers during 2003–2010. Multivariable models were created using Cox proportional hazards regression and ordinal logistic regression to identify predictors of mortality or increased length of stay (LOS). None of the microbial characteristics (PFGE type, agr dysfunction, SCCmec type, and detection of PVL, ACME, and TSST-1) were significantly associated with 30-day mortality or post-infection hospital length of stay, after adjusting for gender, age, previous hospital admission within 12 months, previous MRSA infection or colonization, positive influenza test, Charlson Comorbidity Index score, and treatment (linezolid or vancomycin).
Conclusion Large prospective studies are needed to examine the impact of microbial characteristics on the risk of death and other adverse outcomes among patients with MRSA pneumonia.
The most recent epidemic of Ebola virus disease (EVD), beginning in Guinea in December 2013 and s... more The most recent epidemic of Ebola virus disease (EVD), beginning in Guinea in December 2013 and still underway as of September 2015, has claimed almost 11 300 lives and resulted in almost 28 000 cases. The first EVD epidemic in history to span multiple countries at once; the outbreak caught the world unprepared, undoubtedly leading to higher illness and death counts that may have occurred in areas with solid medical infrastructure. An analysis of the many facets of the epidemic touches on many important topics covered in an introductory global health course, including issues of economics, ethics, culture, infectious disease, policy, preparedness and technology. However, in contrast to many global health offerings, a study of Ebola provides a unifying narrative throughout the course.
The most recent epidemic of Ebola virus disease (EVD), beginning in Guinea in December 2013 and s... more The most recent epidemic of Ebola virus disease (EVD), beginning in Guinea in December 2013 and still underway as of September 2015, has claimed almost 11 300 lives and resulted in almost 28 000 cases. The first EVD epidemic in history to span multiple countries at once; the outbreak caught the world unprepared, undoubtedly leading to higher illness and death counts that may have occurred in areas with solid medical infrastructure. An analysis of the many facets of the epidemic touches on many important topics covered in an introductory global health course, including issues of economics, ethics, culture, infectious disease, policy, preparedness and technology. However, in contrast to many global health offerings, a study of Ebola provides a unifying narrative throughout the course.
The most recent epidemic of Ebola virus disease (EVD), beginning in Guinea in December 2013 and s... more The most recent epidemic of Ebola virus disease (EVD), beginning in Guinea in December 2013 and still underway as of September 2015, has claimed almost 11 300 lives and resulted in almost 28 000 cases. The first EVD epidemic in history to span multiple countries at once; the outbreak caught the world unprepared, undoubtedly leading to higher illness and death counts that may have occurred in areas with solid medical infrastructure. An analysis of the many facets of the epidemic touches on many important topics covered in an introductory global health course, including issues of economics, ethics, culture, infectious disease, policy, preparedness and technology. However, in contrast to many global health offerings, a study of Ebola provides a unifying narrative throughout the course.
Aerosolized methicillin-resistant Staphylococcus aureus (MRSA) was sampled inside and downwind of... more Aerosolized methicillin-resistant Staphylococcus aureus (MRSA) was sampled inside and downwind of a swine facility. Animal feed was sampled before and after entry into the swine facility. Aerosolized particles were detected using an optical particle counter for real time measurement and with an Andersen Sampler to detect viable MRSA. Molecular typing and antimicrobial susceptibility testing were performed on samples collected. Viable MRSA organisms isolated inside the swine facility were primarily associated with particles > 5µm, and those isolated downwind from the swine facility were associated with particles <5µm. MRSA isolates included spa types t008, t034, and t5706 and were resistant to methicillin, tetracycline, clindamycin, and erythromycin. Animal feed both before and after entry into the swine facility tested positive for viable MRSA. These isolates were of similar spa types as the airborne MRSA organisms. Air samples collected after power washing with a biocide inside the swine facility resulted in no viable MRSA organisms detected. Our pilot study showed that the ecology of MRSA is complex. Additional studies are warranted on the maximum distance that viable MRSA can be emitted outside the facility, and the possibility that animal feed may be a source of contamination.
Background. Livestock-associated Staphylococcus aureus (LA-SA) has been documented worldwide. How... more Background. Livestock-associated Staphylococcus aureus (LA-SA) has been documented worldwide. However, much remains unknown about LA-SA colonization and infection, especially in rural environments.
Methods. We conducted a large-scale prospective study of 1342 Iowans, including individuals with livestock contact and a community-based comparison group. Nasal and throat swabs were collected to determine colonization at enrollment, and skin infection swabs over 17 months were assessed for S. aureus. Outcomes included carriage of S. aureus, methicillin-resistant S. aureus (MRSA), tetracycline-resistant S. aureus (TRSA), multidrug-resistant S. aureus (MDRSA), and LA-SA.
Results. Of 1342 participants, 351 (26.2%; 95% confidence interval [CI], 23.8%–28.6%) carried S. aureus. MRSA was isolated from 34 (2.5%; 95% CI, 1.8%–3.5%) and LA-SA from 131 (9.8%; 95% CI, 8.3%–11.5%) of the 1342 participants. Individuals with current swine exposure were significantly more likely to carry S. aureus (prevalence ratio [PR], 1.8; 95% CI, 1.4–2.2), TRSA (PR, 8.4; 95% CI, 5.6–12.6), MDRSA (PR, 6.1; 95% CI, 3.8–10.0), and LA-SA (PR, 5.8; 95% CI, 3.9–8.4) than those lacking exposure. Skin infections (n = 103) were reported from 67 individuals, yielding an incidence rate of 6.6 (95% CI, 4.9–8.9) per 1000 person-months.
Conclusions. Current swine workers are 6 times more likely to carry MDRSA than those without current swine exposure. We observed active infections caused by LA-SA. This finding suggests that individuals with livestock contact may have a high prevalence of exposure to, and potentially infection with, antibiotic-resistant S. aureus strains, including LA-SA strains.
Background. Previous studies indicated that vancomycin is inferior to beta-lactams for treatment ... more Background. Previous studies indicated that vancomycin is inferior to beta-lactams for treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections. However, it is unclear if this association is true for both empiric and definitive therapy. This study compared beta-lactams with vancomycin for empiric and definitive therapy of MSSA bloodstream infections among patients admitted to 122 hospitals.
Methods. This retrospective cohort study included all patients admitted to Veteran's Affairs hospitals from 2003 to 2010 who had positive blood cultures for MSSA. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox proportional hazards regression. Empiric therapy was defined as starting treatment 2 days before until 4 days after the first MSSA blood culture was collected. Definitive therapy was defined as starting treatment between 4 to 14 days after the first positive blood culture was collected.
Results. Patients who received empiric therapy with a beta-lactam had similar mortality compared with vancomycin (HR: 1.03; 95% CI: 0.89-1.20) after adjusting for other factors. However, patients who received definitive therapy with a beta-lactam had 35% lower mortality compared with patients receiving vancomycin (HR: 0.65; CI: 0.52-0.80) after controlling for other factors. The hazard of mortality decreased further for patients who received cefazolin or an antistaphylococcal penicillin compared with vancomycin (HR: 0.57; CI: 0.46-0.71).
Conclusions. For patients with MSSA bloodstream infections, beta-lactams are superior to vancomycin for definitive therapy but not for empiric treatment. Patients should receive a beta-lactam for definitive therapy, specifically an antistaphylococcal penicillin or cefazolin.
The present study was performed to characterize the epidemiology of necrotizing soft tissue infec... more The present study was performed to characterize the epidemiology of necrotizing soft tissue infection caused by Streptococcus pyogenes (n = 14) and Staphylococcus aureus (n = 14) isolates collected at the University of Iowa Hospitals and Clinics. An additional 9 S. pyogenes isolates were collected from patients being treated for mild respiratory infections and served as a comparison sample in the analysis. Patient data corresponding to the isolates (n = 37) were also collected in order to identify risk factors or comorbid conditions possibly correlated with necrotizing fasciitis (NF). The prevalence of methicillin-resistant S. aureus among the study isolates was 35.7% (5/14), and the prevalence of the Panton–Valentine leukocidin (PVL) gene was 57% (8/14). The S. pyogenes NF (wound) isolates (n = 14) belonged to 10 different emm types, none of which appeared to be associated with more severe disease when compared to the milder infection (throat) samples (n = 9). Comorbid conditions such as diabetes and cardiovascular disease were significantly associated with NF. The results indicate that there may be a high prevalence of the PVL virulence factor in NF infections and that spa type t008 may be responsible for the increasing incidence of S. aureus NF infections in Iowa.
Background
Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is associa... more Background
Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is associated with increased infection risk, yet colonization and infection isolates are rarely compared within the same study. The objectives of this study were to compare colonization and infection isolates from a Veterans Administration hospital in Iowa, and to determine the prevalence of livestock-associated MRSA (LA-MRSA) colonization and infection in a state with high livestock density.
Methods
All patients with available MRSA isolates collected through routine nasal screening (73%; n = 397) and from infections (27%; n = 148) between December 2010 and August 2012 were included and tested for spa type and presence of PVL and mecA genes. Clinical isolates were tested for antibiotic resistance patterns. Paired colonization and infection isolates were compared for genetic and phenotypic congruity.
Results
The most common spa types were t002 (and other CC5-associated strains; 65%) and t008 (and other CC8-associated strains; 20%). No classic LA-MRSA spa types were identified. CC5-associated strains were less likely to be associated with infections (22%; 77/353) compared with CC8-associated strains (49%; 53/109). MRSA colonization was more common among patients with infections (71%) compared with the general screening population (7%). In most cases (82%; 28/34), paired colonization and infection isolates were genetically and phenotypically indistinguishable.
Conclusions
Our data demonstrate a direct link between antecedent nasal colonization and subsequent MRSA infection. Further, our data indicate variability in colonization and infection efficiency among MRSA genotypes, which points to the need to define the molecular determinants underlying emergence of S. aureus strains in the community and nosocomial setting.
Antimicrobial resistance and infection control, 2015
Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is associated with inc... more Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is associated with increased infection risk, yet colonization and infection isolates are rarely compared within the same study. The objectives of this study were to compare colonization and infection isolates from a Veterans Administration hospital in Iowa, and to determine the prevalence of livestock-associated MRSA (LA-MRSA) colonization and infection in a state with high livestock density. All patients with available MRSA isolates collected through routine nasal screening (73%; n = 397) and from infections (27%; n = 148) between December 2010 and August 2012 were included and tested for spa type and presence of PVL and mecA genes. Clinical isolates were tested for antibiotic resistance patterns. Paired colonization and infection isolates were compared for genetic and phenotypic congruity. The most common spa types were t002 (and other CC5-associated strains; 65%) and t008 (and other CC8-associated strains;...
Background
Methicillin-resistant S. aureus (MRSA) pneumonia is associated with poor clinical outc... more Background Methicillin-resistant S. aureus (MRSA) pneumonia is associated with poor clinical outcomes. This study examined the association between microbial characteristics and poor outcomes among patients with methicillin-resistant Staphylococcus aureus pneumonia.
Findings This retrospective cohort study included 75 patients with MRSA pneumonia who were admitted to two large tertiary care medical centers during 2003–2010. Multivariable models were created using Cox proportional hazards regression and ordinal logistic regression to identify predictors of mortality or increased length of stay (LOS). None of the microbial characteristics (PFGE type, agr dysfunction, SCCmec type, and detection of PVL, ACME, and TSST-1) were significantly associated with 30-day mortality or post-infection hospital length of stay, after adjusting for gender, age, previous hospital admission within 12 months, previous MRSA infection or colonization, positive influenza test, Charlson Comorbidity Index score, and treatment (linezolid or vancomycin).
Conclusion Large prospective studies are needed to examine the impact of microbial characteristics on the risk of death and other adverse outcomes among patients with MRSA pneumonia.
The most recent epidemic of Ebola virus disease (EVD), beginning in Guinea in December 2013 and s... more The most recent epidemic of Ebola virus disease (EVD), beginning in Guinea in December 2013 and still underway as of September 2015, has claimed almost 11 300 lives and resulted in almost 28 000 cases. The first EVD epidemic in history to span multiple countries at once; the outbreak caught the world unprepared, undoubtedly leading to higher illness and death counts that may have occurred in areas with solid medical infrastructure. An analysis of the many facets of the epidemic touches on many important topics covered in an introductory global health course, including issues of economics, ethics, culture, infectious disease, policy, preparedness and technology. However, in contrast to many global health offerings, a study of Ebola provides a unifying narrative throughout the course.
The most recent epidemic of Ebola virus disease (EVD), beginning in Guinea in December 2013 and s... more The most recent epidemic of Ebola virus disease (EVD), beginning in Guinea in December 2013 and still underway as of September 2015, has claimed almost 11 300 lives and resulted in almost 28 000 cases. The first EVD epidemic in history to span multiple countries at once; the outbreak caught the world unprepared, undoubtedly leading to higher illness and death counts that may have occurred in areas with solid medical infrastructure. An analysis of the many facets of the epidemic touches on many important topics covered in an introductory global health course, including issues of economics, ethics, culture, infectious disease, policy, preparedness and technology. However, in contrast to many global health offerings, a study of Ebola provides a unifying narrative throughout the course.
The most recent epidemic of Ebola virus disease (EVD), beginning in Guinea in December 2013 and s... more The most recent epidemic of Ebola virus disease (EVD), beginning in Guinea in December 2013 and still underway as of September 2015, has claimed almost 11 300 lives and resulted in almost 28 000 cases. The first EVD epidemic in history to span multiple countries at once; the outbreak caught the world unprepared, undoubtedly leading to higher illness and death counts that may have occurred in areas with solid medical infrastructure. An analysis of the many facets of the epidemic touches on many important topics covered in an introductory global health course, including issues of economics, ethics, culture, infectious disease, policy, preparedness and technology. However, in contrast to many global health offerings, a study of Ebola provides a unifying narrative throughout the course.
Aerosolized methicillin-resistant Staphylococcus aureus (MRSA) was sampled inside and downwind of... more Aerosolized methicillin-resistant Staphylococcus aureus (MRSA) was sampled inside and downwind of a swine facility. Animal feed was sampled before and after entry into the swine facility. Aerosolized particles were detected using an optical particle counter for real time measurement and with an Andersen Sampler to detect viable MRSA. Molecular typing and antimicrobial susceptibility testing were performed on samples collected. Viable MRSA organisms isolated inside the swine facility were primarily associated with particles > 5µm, and those isolated downwind from the swine facility were associated with particles <5µm. MRSA isolates included spa types t008, t034, and t5706 and were resistant to methicillin, tetracycline, clindamycin, and erythromycin. Animal feed both before and after entry into the swine facility tested positive for viable MRSA. These isolates were of similar spa types as the airborne MRSA organisms. Air samples collected after power washing with a biocide inside the swine facility resulted in no viable MRSA organisms detected. Our pilot study showed that the ecology of MRSA is complex. Additional studies are warranted on the maximum distance that viable MRSA can be emitted outside the facility, and the possibility that animal feed may be a source of contamination.
Background. Livestock-associated Staphylococcus aureus (LA-SA) has been documented worldwide. How... more Background. Livestock-associated Staphylococcus aureus (LA-SA) has been documented worldwide. However, much remains unknown about LA-SA colonization and infection, especially in rural environments.
Methods. We conducted a large-scale prospective study of 1342 Iowans, including individuals with livestock contact and a community-based comparison group. Nasal and throat swabs were collected to determine colonization at enrollment, and skin infection swabs over 17 months were assessed for S. aureus. Outcomes included carriage of S. aureus, methicillin-resistant S. aureus (MRSA), tetracycline-resistant S. aureus (TRSA), multidrug-resistant S. aureus (MDRSA), and LA-SA.
Results. Of 1342 participants, 351 (26.2%; 95% confidence interval [CI], 23.8%–28.6%) carried S. aureus. MRSA was isolated from 34 (2.5%; 95% CI, 1.8%–3.5%) and LA-SA from 131 (9.8%; 95% CI, 8.3%–11.5%) of the 1342 participants. Individuals with current swine exposure were significantly more likely to carry S. aureus (prevalence ratio [PR], 1.8; 95% CI, 1.4–2.2), TRSA (PR, 8.4; 95% CI, 5.6–12.6), MDRSA (PR, 6.1; 95% CI, 3.8–10.0), and LA-SA (PR, 5.8; 95% CI, 3.9–8.4) than those lacking exposure. Skin infections (n = 103) were reported from 67 individuals, yielding an incidence rate of 6.6 (95% CI, 4.9–8.9) per 1000 person-months.
Conclusions. Current swine workers are 6 times more likely to carry MDRSA than those without current swine exposure. We observed active infections caused by LA-SA. This finding suggests that individuals with livestock contact may have a high prevalence of exposure to, and potentially infection with, antibiotic-resistant S. aureus strains, including LA-SA strains.
Background. Previous studies indicated that vancomycin is inferior to beta-lactams for treatment ... more Background. Previous studies indicated that vancomycin is inferior to beta-lactams for treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections. However, it is unclear if this association is true for both empiric and definitive therapy. This study compared beta-lactams with vancomycin for empiric and definitive therapy of MSSA bloodstream infections among patients admitted to 122 hospitals.
Methods. This retrospective cohort study included all patients admitted to Veteran's Affairs hospitals from 2003 to 2010 who had positive blood cultures for MSSA. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox proportional hazards regression. Empiric therapy was defined as starting treatment 2 days before until 4 days after the first MSSA blood culture was collected. Definitive therapy was defined as starting treatment between 4 to 14 days after the first positive blood culture was collected.
Results. Patients who received empiric therapy with a beta-lactam had similar mortality compared with vancomycin (HR: 1.03; 95% CI: 0.89-1.20) after adjusting for other factors. However, patients who received definitive therapy with a beta-lactam had 35% lower mortality compared with patients receiving vancomycin (HR: 0.65; CI: 0.52-0.80) after controlling for other factors. The hazard of mortality decreased further for patients who received cefazolin or an antistaphylococcal penicillin compared with vancomycin (HR: 0.57; CI: 0.46-0.71).
Conclusions. For patients with MSSA bloodstream infections, beta-lactams are superior to vancomycin for definitive therapy but not for empiric treatment. Patients should receive a beta-lactam for definitive therapy, specifically an antistaphylococcal penicillin or cefazolin.
The present study was performed to characterize the epidemiology of necrotizing soft tissue infec... more The present study was performed to characterize the epidemiology of necrotizing soft tissue infection caused by Streptococcus pyogenes (n = 14) and Staphylococcus aureus (n = 14) isolates collected at the University of Iowa Hospitals and Clinics. An additional 9 S. pyogenes isolates were collected from patients being treated for mild respiratory infections and served as a comparison sample in the analysis. Patient data corresponding to the isolates (n = 37) were also collected in order to identify risk factors or comorbid conditions possibly correlated with necrotizing fasciitis (NF). The prevalence of methicillin-resistant S. aureus among the study isolates was 35.7% (5/14), and the prevalence of the Panton–Valentine leukocidin (PVL) gene was 57% (8/14). The S. pyogenes NF (wound) isolates (n = 14) belonged to 10 different emm types, none of which appeared to be associated with more severe disease when compared to the milder infection (throat) samples (n = 9). Comorbid conditions such as diabetes and cardiovascular disease were significantly associated with NF. The results indicate that there may be a high prevalence of the PVL virulence factor in NF infections and that spa type t008 may be responsible for the increasing incidence of S. aureus NF infections in Iowa.
Background
Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is associa... more Background
Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is associated with increased infection risk, yet colonization and infection isolates are rarely compared within the same study. The objectives of this study were to compare colonization and infection isolates from a Veterans Administration hospital in Iowa, and to determine the prevalence of livestock-associated MRSA (LA-MRSA) colonization and infection in a state with high livestock density.
Methods
All patients with available MRSA isolates collected through routine nasal screening (73%; n = 397) and from infections (27%; n = 148) between December 2010 and August 2012 were included and tested for spa type and presence of PVL and mecA genes. Clinical isolates were tested for antibiotic resistance patterns. Paired colonization and infection isolates were compared for genetic and phenotypic congruity.
Results
The most common spa types were t002 (and other CC5-associated strains; 65%) and t008 (and other CC8-associated strains; 20%). No classic LA-MRSA spa types were identified. CC5-associated strains were less likely to be associated with infections (22%; 77/353) compared with CC8-associated strains (49%; 53/109). MRSA colonization was more common among patients with infections (71%) compared with the general screening population (7%). In most cases (82%; 28/34), paired colonization and infection isolates were genetically and phenotypically indistinguishable.
Conclusions
Our data demonstrate a direct link between antecedent nasal colonization and subsequent MRSA infection. Further, our data indicate variability in colonization and infection efficiency among MRSA genotypes, which points to the need to define the molecular determinants underlying emergence of S. aureus strains in the community and nosocomial setting.
Evolution is the unifying theory in all of biology, but is frequently missing from curricula in m... more Evolution is the unifying theory in all of biology, but is frequently missing from curricula in medicine and public health. Yet evolution has shaped the burden of disease in the modern world in which we practice medicine and educate for public health, and understanding the interface between evolutionary biology and the biomedical sciences may lead to improved medical therapies and public health practices. This course, appropriate for undergraduates in Biology, Anthropology, Public Health, and Nursing, among others, will examine what has been termed “evolutionary medicine” or “Darwinian medicine,” examining connections between evolution and biomedicine including infectious diseases, cancer, aging, and human genetic diseases.
Infectious disease affects us all, but many areas within the field are controversial. Should I tr... more Infectious disease affects us all, but many areas within the field are controversial. Should I treat my child’s ear infection with antibiotics? Should I vaccinate my child (or myself?) How do infectious diseases contribute to other “chronic” diseases? How does culture and social standing affect outcomes of infectious disease outbreaks? This course is appropriate both for humanities majors looking for an introduction to infectious diseases as well as science majors looking to better understand infectious diseases in their historical and cultural context, and the way these diseases have (and continue to) shape history, including the questions above. Ultimately, students should be able to understand the basics of infectious disease epidemiology and disease control within a wide cultural context. The course will encompass various topics in the history of microbiology and infectious disease, using primarily popular non-fiction books on these subjects as sources.
This course is designed to provide students with an advanced understanding of the epidemiology of... more This course is designed to provide students with an advanced understanding of the epidemiology of infectious diseases. In this course, the history, principles, methods, and practice of infectious disease epidemiology will be surveyed. Epidemiologic surveillance, disease outbreak investigation, and other methods used to elucidate the epidemiology of infectious diseases will be reviewed. The descriptive epidemiology of important infectious diseases of humans will be considered and the implications of this epidemiology for prevention and control discussed. While the focus of this course is on epidemiology of infectious diseases, the readings and discussions will incorporate relevant aspects of the microbiology of infectious agents of disease.
Ebola has been known to humankind for almost 40 years, but the recent outbreak in West Africa has... more Ebola has been known to humankind for almost 40 years, but the recent outbreak in West Africa has brought it to the public consciousness like no time before. However, many people don’t know the story of the Ebola virus. What is its history? Why did this outbreak happen? How did it jump to the United States? How and why did the West African outbreak begin in the first place? This course will cover the history of the virus, and the biological, social, and political aspects that have made this outbreak into the largest Ebola outbreak on record by far.
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Methicillin-resistant S. aureus (MRSA) pneumonia is associated with poor clinical outcomes. This study examined the association between microbial characteristics and poor outcomes among patients with methicillin-resistant Staphylococcus aureus pneumonia.
Findings
This retrospective cohort study included 75 patients with MRSA pneumonia who were admitted to two large tertiary care medical centers during 2003–2010. Multivariable models were created using Cox proportional hazards regression and ordinal logistic regression to identify predictors of mortality or increased length of stay (LOS). None of the microbial characteristics (PFGE type, agr dysfunction, SCCmec type, and detection of PVL, ACME, and TSST-1) were significantly associated with 30-day mortality or post-infection hospital length of stay, after adjusting for gender, age, previous hospital admission within 12 months, previous MRSA infection or colonization, positive influenza test, Charlson Comorbidity Index score, and treatment (linezolid or vancomycin).
Conclusion
Large prospective studies are needed to examine the impact of microbial characteristics on the risk of death and other adverse outcomes among patients with MRSA pneumonia.
Methods. We conducted a large-scale prospective study of 1342 Iowans, including individuals with livestock contact and a community-based comparison group. Nasal and throat swabs were collected to determine colonization at enrollment, and skin infection swabs over 17 months were assessed for S. aureus. Outcomes included carriage of S. aureus, methicillin-resistant S. aureus (MRSA), tetracycline-resistant S. aureus (TRSA), multidrug-resistant S. aureus (MDRSA), and LA-SA.
Results. Of 1342 participants, 351 (26.2%; 95% confidence interval [CI], 23.8%–28.6%) carried S. aureus. MRSA was isolated from 34 (2.5%; 95% CI, 1.8%–3.5%) and LA-SA from 131 (9.8%; 95% CI, 8.3%–11.5%) of the 1342 participants. Individuals with current swine exposure were significantly more likely to carry S. aureus (prevalence ratio [PR], 1.8; 95% CI, 1.4–2.2), TRSA (PR, 8.4; 95% CI, 5.6–12.6), MDRSA (PR, 6.1; 95% CI, 3.8–10.0), and LA-SA (PR, 5.8; 95% CI, 3.9–8.4) than those lacking exposure. Skin infections (n = 103) were reported from 67 individuals, yielding an incidence rate of 6.6 (95% CI, 4.9–8.9) per 1000 person-months.
Conclusions. Current swine workers are 6 times more likely to carry MDRSA than those without current swine exposure. We observed active infections caused by LA-SA. This finding suggests that individuals with livestock contact may have a high prevalence of exposure to, and potentially infection with, antibiotic-resistant S. aureus strains, including LA-SA strains.
Methods. This retrospective cohort study included all patients admitted to Veteran's Affairs hospitals from 2003 to 2010 who had positive blood cultures for MSSA. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox proportional hazards regression. Empiric therapy was defined as starting treatment 2 days before until 4 days after the first MSSA blood culture was collected. Definitive therapy was defined as starting treatment between 4 to 14 days after the first positive blood culture was collected.
Results. Patients who received empiric therapy with a beta-lactam had similar mortality compared with vancomycin (HR: 1.03; 95% CI: 0.89-1.20) after adjusting for other factors. However, patients who received definitive therapy with a beta-lactam had 35% lower mortality compared with patients receiving vancomycin (HR: 0.65; CI: 0.52-0.80) after controlling for other factors. The hazard of mortality decreased further for patients who received cefazolin or an antistaphylococcal penicillin compared with vancomycin (HR: 0.57; CI: 0.46-0.71).
Conclusions. For patients with MSSA bloodstream infections, beta-lactams are superior to vancomycin for definitive therapy but not for empiric treatment. Patients should receive a beta-lactam for definitive therapy, specifically an antistaphylococcal penicillin or cefazolin.
Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is associated with increased infection risk, yet colonization and infection isolates are rarely compared within the same study. The objectives of this study were to compare colonization and infection isolates from a Veterans Administration hospital in Iowa, and to determine the prevalence of livestock-associated MRSA (LA-MRSA) colonization and infection in a state with high livestock density.
Methods
All patients with available MRSA isolates collected through routine nasal screening (73%; n = 397) and from infections (27%; n = 148) between December 2010 and August 2012 were included and tested for spa type and presence of PVL and mecA genes. Clinical isolates were tested for antibiotic resistance patterns. Paired colonization and infection isolates were compared for genetic and phenotypic congruity.
Results
The most common spa types were t002 (and other CC5-associated strains; 65%) and t008 (and other CC8-associated strains; 20%). No classic LA-MRSA spa types were identified. CC5-associated strains were less likely to be associated with infections (22%; 77/353) compared with CC8-associated strains (49%; 53/109). MRSA colonization was more common among patients with infections (71%) compared with the general screening population (7%). In most cases (82%; 28/34), paired colonization and infection isolates were genetically and phenotypically indistinguishable.
Conclusions
Our data demonstrate a direct link between antecedent nasal colonization and subsequent MRSA infection. Further, our data indicate variability in colonization and infection efficiency among MRSA genotypes, which points to the need to define the molecular determinants underlying emergence of S. aureus strains in the community and nosocomial setting.
Methicillin-resistant S. aureus (MRSA) pneumonia is associated with poor clinical outcomes. This study examined the association between microbial characteristics and poor outcomes among patients with methicillin-resistant Staphylococcus aureus pneumonia.
Findings
This retrospective cohort study included 75 patients with MRSA pneumonia who were admitted to two large tertiary care medical centers during 2003–2010. Multivariable models were created using Cox proportional hazards regression and ordinal logistic regression to identify predictors of mortality or increased length of stay (LOS). None of the microbial characteristics (PFGE type, agr dysfunction, SCCmec type, and detection of PVL, ACME, and TSST-1) were significantly associated with 30-day mortality or post-infection hospital length of stay, after adjusting for gender, age, previous hospital admission within 12 months, previous MRSA infection or colonization, positive influenza test, Charlson Comorbidity Index score, and treatment (linezolid or vancomycin).
Conclusion
Large prospective studies are needed to examine the impact of microbial characteristics on the risk of death and other adverse outcomes among patients with MRSA pneumonia.
Methods. We conducted a large-scale prospective study of 1342 Iowans, including individuals with livestock contact and a community-based comparison group. Nasal and throat swabs were collected to determine colonization at enrollment, and skin infection swabs over 17 months were assessed for S. aureus. Outcomes included carriage of S. aureus, methicillin-resistant S. aureus (MRSA), tetracycline-resistant S. aureus (TRSA), multidrug-resistant S. aureus (MDRSA), and LA-SA.
Results. Of 1342 participants, 351 (26.2%; 95% confidence interval [CI], 23.8%–28.6%) carried S. aureus. MRSA was isolated from 34 (2.5%; 95% CI, 1.8%–3.5%) and LA-SA from 131 (9.8%; 95% CI, 8.3%–11.5%) of the 1342 participants. Individuals with current swine exposure were significantly more likely to carry S. aureus (prevalence ratio [PR], 1.8; 95% CI, 1.4–2.2), TRSA (PR, 8.4; 95% CI, 5.6–12.6), MDRSA (PR, 6.1; 95% CI, 3.8–10.0), and LA-SA (PR, 5.8; 95% CI, 3.9–8.4) than those lacking exposure. Skin infections (n = 103) were reported from 67 individuals, yielding an incidence rate of 6.6 (95% CI, 4.9–8.9) per 1000 person-months.
Conclusions. Current swine workers are 6 times more likely to carry MDRSA than those without current swine exposure. We observed active infections caused by LA-SA. This finding suggests that individuals with livestock contact may have a high prevalence of exposure to, and potentially infection with, antibiotic-resistant S. aureus strains, including LA-SA strains.
Methods. This retrospective cohort study included all patients admitted to Veteran's Affairs hospitals from 2003 to 2010 who had positive blood cultures for MSSA. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox proportional hazards regression. Empiric therapy was defined as starting treatment 2 days before until 4 days after the first MSSA blood culture was collected. Definitive therapy was defined as starting treatment between 4 to 14 days after the first positive blood culture was collected.
Results. Patients who received empiric therapy with a beta-lactam had similar mortality compared with vancomycin (HR: 1.03; 95% CI: 0.89-1.20) after adjusting for other factors. However, patients who received definitive therapy with a beta-lactam had 35% lower mortality compared with patients receiving vancomycin (HR: 0.65; CI: 0.52-0.80) after controlling for other factors. The hazard of mortality decreased further for patients who received cefazolin or an antistaphylococcal penicillin compared with vancomycin (HR: 0.57; CI: 0.46-0.71).
Conclusions. For patients with MSSA bloodstream infections, beta-lactams are superior to vancomycin for definitive therapy but not for empiric treatment. Patients should receive a beta-lactam for definitive therapy, specifically an antistaphylococcal penicillin or cefazolin.
Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is associated with increased infection risk, yet colonization and infection isolates are rarely compared within the same study. The objectives of this study were to compare colonization and infection isolates from a Veterans Administration hospital in Iowa, and to determine the prevalence of livestock-associated MRSA (LA-MRSA) colonization and infection in a state with high livestock density.
Methods
All patients with available MRSA isolates collected through routine nasal screening (73%; n = 397) and from infections (27%; n = 148) between December 2010 and August 2012 were included and tested for spa type and presence of PVL and mecA genes. Clinical isolates were tested for antibiotic resistance patterns. Paired colonization and infection isolates were compared for genetic and phenotypic congruity.
Results
The most common spa types were t002 (and other CC5-associated strains; 65%) and t008 (and other CC8-associated strains; 20%). No classic LA-MRSA spa types were identified. CC5-associated strains were less likely to be associated with infections (22%; 77/353) compared with CC8-associated strains (49%; 53/109). MRSA colonization was more common among patients with infections (71%) compared with the general screening population (7%). In most cases (82%; 28/34), paired colonization and infection isolates were genetically and phenotypically indistinguishable.
Conclusions
Our data demonstrate a direct link between antecedent nasal colonization and subsequent MRSA infection. Further, our data indicate variability in colonization and infection efficiency among MRSA genotypes, which points to the need to define the molecular determinants underlying emergence of S. aureus strains in the community and nosocomial setting.