Abinash Virk

Clinical Aspects of Antimicrobial Resistance

Soon after penicillin was introduced into clinical use, an enzyme (penicillinase) that inactivated it was discovered. Since then, the variety of antimicrobial agents has increased substantially, along with a parallel increase in resistant pathogenic microorganisms. Resistance is now recognized against all available antimicrobial agents. Factors influencing the emergence of resistance include indiscriminate use of antibiotics, prolonged hospitalizations, increasing numbers of immunocompromised patients, and medical progress resulting in increased use of invasive procedures and devices. This article provides an update on clinical aspects of a few commonly found resistant microorganisms relevant to day-to-day clinical practice. A discussion of all resistant organisms is beyond the scope of this report. Both viral and mycobacterial resistance have been addressed in previous articles in this symposium.

Infective endocarditis due to Propionibacterium species

Propionibacterium species rarely cause infective endocarditis. When identified in blood cultures, they may be inappropriately disregarded as skin flora contaminants. The purpose of this study was to characterize the clinical presentation and management of endocarditis due to Propionibacterium species. All cases of endocarditis due to Propionibacterium species that were treated at the Mayo Clinic, Rochester, USA were retrospectively reviewed, and the English language medical literature was searched for all previously published reports. Seventy cases, which included eight from the Mayo Clinic, were identified (clinical details were available for only 58 cases). The median age of patients was 52 years, and 90% were males. In 79% of the cases, the infection involved prosthetic material (39 prosthetic valves, one left ventricular Teflon patch, one mitral valve ring, one pulmonary artery prosthetic graft, three pacemakers, and one defibrillator). Blood cultures were positive in 62% of cases. All 22 cases with negative blood cultures were microbiologically confirmed by either positive valve tissue cultures (n = 21) or molecular methods (n = 1). Endocarditis was complicated by abscess formation in 36% of cases. The majority (81%) of patients underwent surgery, either for valve replacement and debridement of a cardiac abscess, or removal of an infected device. Crude in-hospital mortality was 16%. The median duration of postoperative antibiotic treatment was 42 days. Patients were commonly treated with a penicillin derivative alone or in combination with gentamicin. On the basis of the above data, it is recommended that infective endocarditis should be strongly suspected when Propionibacterium species are isolated from multiple blood cultures, particularly in the presence of a cardiovascular device.

International travel and exposure risks in solid-organ transplant recipients.

Background. Although solid-organ transplant recipients (SOTR) have an increased risk of acquiring illnesses, they may not receive optimal pretravel care. We conducted a cross-sectional survey of travel activities and outcomes among SOTR. Methods. Two thousand five hundred fifty-four consecutive living SOTR from Mayo Clinic were surveyed regarding travel practices, pretravel counseling, exposure risks, and illness using a previously standardized and validated questionnaire. Results. One thousand one hundred thirty SOTR (44%) responded to the survey and were included in the study. The most common transplanted organs were liver (519 patients) and kidney (515 patients). Three hundred and three (27%) respondents reported travel outside of the United States or Canada after their transplant. Liver recipients were more likely to travel than other organ recipients. Ninety-six percent of travelers reported that they did not seek specific pretravel healthcare before their trip. Forty-nine SOTR (16%) traveled to destinations at higher risk for infectious diseases; travelers to these destinations were more likely to be men (73% vs. 54% of low-infection risk travelers, P=0.018) or born outside the United Stated or Canada (29% vs. 6% P<0.0001). Twenty-four travelers (8%) required medical attention because of illness; illness was more likely among travelers to high-infection risk (18%) than low-risk (6%) destinations, P=0.004. Conclusions. International travel was common after solid organ transplantation, although the majority traveled to destinations at low risk for infectious disease. Although generally SOTR were able to travel safely, travelers to destinations at high-risk for infection had a significant rate of illness. Pretravel counseling and interventions were infrequent and should be improved.

Severe Pleuropulmonary Paragonimiasis 8 Years after Emigration from a Region of Endemicity

A Laotian man who had resided only in the north-central United States for 8 years sought care for an acute, progressive syndrome of severe dyspnea, chest pain, bilateral pneumothoraces, lung and liver nodules, and marked peripheral blood eosinophilia. He habitually ate raw crabmeat imported pickled or frozen from Southeast Asia; he denied eating local crustaceans. Ova consistent with the lung fluke Paragonimus westermani were identified in a bronchoalveolar lavage specimen, and the eosinophilia and pulmonary symptoms resolved with praziquantel therapy.

Medical Advice for International Travelers

Each year, approximately 30 to 40 million Americans travel outside the United States. Although the most popular destinations are Europe, Central America, and the Caribbean, travel to Africa and Asia is increasing substantially. International travel, particularly to developing countries, can be associated with the risk of infectious and noninfectious diseases. These risks can be decreased, eliminated, or modified with vaccinations, prophylactic medications, and education. Optimally, pretravel advice must be individualized to a persons medical history, itinerary, and risk behavior. In addition to risk assessment-based immunizations, issues such as travelers diarrhea, malaria prophylaxis, sexually transmitted diseases, and management of underlying medical problems must form a part of pretravel management. Adventure or prolonged travel or persons with underlying medical diseases such as insulin-dependent diabetes mellitus, transplantation, immunodeficiencies, and dialysis warrant additional preventive measures. This review primarily updates pretravel management of adults.

Streptococcus suis-related prosthetic joint infection and streptococcal toxic shock-like syndrome in a pig farmer in the United States

ABSTRACT Streptococcus suis is an emerging swine-associated zoonotic agent that can cause meningitis and septicemia in humans. We present, to our knowledge, the first case of S. suis arthroplasty infection and streptococcal toxic shock-like syndrome due to an nonencapsulated serotype 5 strain in North America.

Temporal Trends in the Incidence of Surgical Site Infections in Patients Undergoing Coronary Artery Bypass Graft Surgery: A Population-Based Cohort Study, 1993 to 2008

OBJECTIVE To determine the incidence of and temporal trends in surgical site infections (SSIs) in patients undergoing coronary artery bypass graft (CABG) surgery. METHODS A population-based cohort study was conducted to describe the epidemiologic features of SSI in Olmsted County, Minnesota, between January 1, 1993, and December 31, 2008, using the Rochester Epidemiology Project. Period-specific incidence rates (in-hospital or within 30 days outside the hospital) were calculated. Logistic regression analysis was used to adjust for potential confounders that could affect temporal trends in SSI incidence rates. RESULTS During the 16-year study, of 1424 residents of Olmsted County who underwent CABG surgery, 1189 (83%) had isolated CABG and 235 (17%) had combined CABG and valve surgery. The overall SSI incidence rate was 7.0% (95% confidence interval [CI], 5.7%-8.4%). The incidence rate of superficial sternal SSI was 2.0% (95% CI, 1.2%-2.7%) and of deep sternal SSI was 1.5% (95% CI, 0.9%-2.2%). The leg harvest site infection rate was 3.6% (95% CI, 2.6 %-4.5%). The incidence rate decreased over time with a statistically significant linear trend. The adjusted odds ratio (95% CI) of SSI showed a decreasing linear trend: 0.39 (0.19-0.81) vs 0.50 (0.27-0.93) vs 0.83 (0.48-1.42) vs reference for 2005-2008 vs 2001-2004 vs 1997-2000 vs 1993-1996. CONCLUSION In this population-based surveillance study of patients undergoing CABG surgery, the incidence of SSI decreased markedly between 1993 and 2008 in patients in Olmsted County. The factors responsible for this decrease are the focus of ongoing investigations.

Incidence of invasive pneumococcal disease among children after introduction of a 7-valent pneumococcal conjugate vaccine: a population-based study in Olmsted County, Minnesota.

OBJECTIVE To examine the effect of the 7-valent pneumococcal conjugate vaccine in a well-characterized population in Olmsted County, Minnesota, with a combination of urban and rural residents likely to have a relatively low risk of invasive pneumococcal disease (IPD). PATIENTS AND METHODS This population-based study analyzed data from children younger than 5 years to determine the incidence of IPD from January 1, 1995, to December 31, 2007. RESULTS From 1995 through 2007, 29 cases of IPD were identified in the study population, but 2 patients denied research authorization; thus, 27 cases were available for review. From 1995-1999 to 2001-2003, the incidence of IPD decreased from 33.5 (95% confidence interval [CI], 16.6-50.5) to 10.8 (95% CI, 0.0-23.0) cases per 100,000 person-years (68% decrease; P =.046). The incidence subsequently increased to 15.2 (95% CI, 3.0-27.4) cases per 100,000 person-years from 2004 through 2007; however this change was not significant ( P =.62). All cases of IPD with available serotype data from 2002 through 2007 (n=5) were due to non-7-valent conjugate vaccine serotypes. CONCLUSION Although the baseline incidence of IPD was much lower than that reported in other populations, the overall incidence of IPD decreased significantly in children younger than 5 years after introduction of a 7-valent conjugate vaccine.

Cystatin C–Guided Vancomycin Dosing in Critically Ill Patients: A Quality Improvement Project

BACKGROUND The aim of the study was to determine whether a vancomycin dosing algorithm based on estimated glomerular filtration rate from creatinine and cystatin C levels (eGFRcr-cys) improves target trough concentration achievement compared to an algorithm based on estimated creatinine clearance (eCLcr) in critically ill patients. STUDY DESIGN This prospective quality improvement project evaluated intensive care unit (ICU) patients started on intravenous vancomycin using one of 2 different strategies. Dosing regimens were selected and implemented after an individualized goal trough range was established (10-15 or 15-20mg/L). Steady-state goal trough achievement was compared between treatment arms with and without adjustment for potential confounders. SETTING & PARTICIPANTS 3 medical and surgical ICUs at a single tertiary medical center. QUALITY IMPROVEMENT PLAN During January 2012 to October 2013, vancomycin was dosed according to eCLcr using the Cockcroft-Gault formula (control arm). During December 2013 to May 2015, a multidisciplinary quality improvement team implemented a novel vancomycin dosing algorithm according to eGFRcr-cys using the CKD-EPI equation (intervention arm). OUTCOME Steady-state initial goal vancomycin trough concentration achievement. MEASUREMENTS & RESULTS More patients in the intervention arm (67 of 135 [50%]) achieved therapeutic trough vancomycin levels than in the control arm (74 of 264 [28%]; OR, 2.53; 95% CI, 1.65-3.90; P<0.001). Improved trough achievement was maintained even after adjustment for age, sex, APACHE (Acute Physiology and Chronic Health Evaluation) III score, fluid balance, baseline CLcr, surgical admission diagnosis, presence of sepsis, and goal trough concentration range (adjusted OR, 2.79; 95% CI, 1.76-4.44; P<0.001). Clinical outcomes were similar between groups. LIMITATIONS Nonrandomized, incomplete algorithm compliance. CONCLUSIONS A vancomycin dosing nomogram based on eGFRcr-cys significantly improved goal trough achievement compared to eCLcr among ICU patients with stable kidney function. Further studies are warranted to characterize the relationship between use of cystatin C-guided dosing and clinical outcomes.

Outcomes in Patients With Cardiovascular Implantable Electronic Device Infection Managed With Chronic Antibiotic Suppression

Background. Most cardiovascular implantable electronic device (CIED) recipients are elderly, have multiple comorbid conditions, and are at increased risk of CIED infection (CIEDI). Current guidelines recommend complete device removal in patients with CIEDI to prevent relapse and mortality. However, comorbidities or other factors may preclude device removal, thus prompting a nonsurgical approach that includes chronic antibiotic suppression (CAS). There are limited data on outcomes of patients receiving CAS for CIEDI. Methods. We retrospectively screened 660 CIEDI cases from 2005 to 2015 using electronic health records and a CIEDI institutional database and identified 48 patients prescribed CAS. Primary outcomes were infection relapse and survival. Results. The median age was 78 years, and 73% (35/48) were male. The median Charlson comorbidity index was 4. Common pathogens were coagulase-negative staphylococci (21%, 10/48) and methicillin-sensitive Staphylococcus aureus (19%, 9/48). At 1 month after hospitalization, 25% (12/48) of patients had died, of whom only 1 initiated CAS; 67% (8/12) of these had staphylococcal infections. Of the 37 patients who initiated CAS, the most common antimicrobials were trimethoprim-sulfamethoxazole, penicillin, and amoxicillin (22%, 8/37 each). Estimated median overall survival was 1.43 years (95% confidence interval, 0.27-2.14), with 18% (6/33 survivors) developing relapse within 1 year. Of the 6 patients who relapsed, 2 (33%) subsequently underwent CIED extraction. Conclusion. CAS is reasonable in select patients who are not candidates for complete device removal for attempted cure of CIEDI. Nevertheless, 1-month mortality in our sample of CAS-eligible patients was high and reflective of high rates of comorbid conditions.