Priya Sampathkumar

Herpes zoster (shingles) and postherpetic neuralgia.

Herpes zoster (HZ), commonly called shingles, is a distinctive syndrome caused by reactivation of varicella zoster virus (VZV). This reactivation occurs when immunity to VZV declines because of aging or immunosuppression. Herpes zoster can occur at any age but most commonly affects the elderly population. Postherpetic neuralgia (PHN), defined as pain persisting more than 3 months after the rash has healed, is a debilitating and difficult to manage consequence of HZ. The diagnosis of HZ is usually made clinically on the basis of the characteristic appearance of the rash. Early recognition and treatment can reduce acute symptoms and may also reduce PHN. A live, attenuated vaccine aimed at boosting immunity to VZV and reducing the risk of HZ is now available and is recommended for adults older than 60 years. The vaccine has been shown to reduce significantly the incidence of both HZ and PHN. The vaccine is well tolerated, with minor local injection site reactions being the most common adverse event. This review focuses on the clinical manifestations and treatment of HZ and PHN, as well as the appropriate use of the HZ vaccine.

Duration of Influenza A Virus Shedding in Hospitalized Patients and Implications for Infection Control

OBJECTIVE To assess the duration of shedding of influenza A virus detected by polymerase chain reaction (PCR) and cell culture among patients hospitalized with influenza A virus infection. SETTING Mayo Clinic (Rochester, Minnesota) hospitals that cater to both the community and referral populations. METHODS Patients 18 years old and older who were hospitalized between December 1, 2004, and March 15, 2005, with a laboratory-confirmed (ie, PCR-based) diagnosis of influenza A virus infection were consecutively enrolled. Additional throat swab specimens were collected at 2, 3, 5, and 7 days after the initial specimen (if the patient was still hospitalized). All specimens were tested by PCR and culture (both conventional tube culture and shell vial assay). Information on demographic characteristics, date of symptom onset, comorbidities, immunosuppression, influenza vaccination status, and receipt of antiviral treatment was obtained by interview and medical record review. Patients were excluded if informed consent could not be obtained or if the date of symptom onset could not be ascertained. RESULTS Of 149 patients hospitalized with influenza A virus infection, 50 patients were enrolled in the study. Most patients were older (median age, 76 years), and almost all (96%) had underlying chronic medical conditions. Of 41 patients included in the final analysis, influenza A virus was detected in 22 (54%) by PCR and in 12 (29%) by culture methods at or beyond 7 days after symptom onset. All 12 patients identified by culture also had PCR results positive for influenza A virus. CONCLUSION Hospitalized patients with influenza A virus infection can shed detectable virus beyond the 5- to 7-day period traditionally considered the duration of infectivity. Additional research is needed to assess whether prolonging the duration of patient isolation is warranted to prevent nosocomial outbreaks during the influenza season.

West Nile Virus: Epidemiology, Clinical Presentation, Diagnosis, and Prevention

West Nile virus was recognized in the United States for the first time in 1999, when it caused an epidemic of encephalitis and meningitis in New York City, NY. Since then, the disease has been steadily moving westward, and human cases were recognized in 39 states and the District of Columbia in 2002. The infection is caused by a flavivirus that is transmitted from birds to humans through the bite of culicine mosquitoes. Most infections are mild, with symptoms primarily being fever, headache, and myalgias. People older than 50 years are at highest risk of severe disease, which may include encephalomyelitis. In 2002, 5 new modes of transmission were recognized: blood product transfusion, organ transplantation, breast-feeding, transplacental transmission, and occupational exposure in laboratory workers. The transmission season was long, with cases occurring into December in some parts of the United States. Currently, there is no specific drug treatment or vaccine against the infection, and avoiding mosquito bites is the best way to protect against the disease.

Fusarium infection after solid-organ transplantation.

We describe a case of soft tissue infection caused by Fusarium species in a heart-liver transplant recipient, and review the cases of fusarial infection reported among solid-organ transplant (SOT) recipients. Unlike fusarial infection in patients with hematologic malignancies or bone marrow transplants, fusarial infection in SOT recipients tends to be localized, occurs later in the posttransplantation period, and has a better outcome. Surgical resection, when possible, and prolonged treatment with amphotericin provide the most effective form of therapy.

Prosthetic Joint Infection Due to Staphylococcus lugdunensis

Staphylococcus lugdunensis, a coagulase-negative staphylococcus, is being increasingly recognized as the cause of serious infections. We report 2 cases of total knee arthroplasty infection caused by S lugdunensis. S lugdunensis frequently produces a clumping factor that can result in a positive slide (short) coagulase test result. If the microbiology laboratory does not use the tube coagulase (long) test to confirm the slide coagulase test result, the organism may be misidentified as Staphylococcus aureus. S lugdunensis is more virulent than other coagulase-negative staphylococci and in many clinical situations behaves like S aureus, further increasing the confusion. However, S lugdunensis differs from S aureus in that it is susceptible to most antibiotics. This fact may alert the microbiology laboratory or the clinician that the isolate is likely not S aureus and prompt further testing of a specific isolate. Accurate identification of S lugdunensis isolates facilitates studies to define the epidemiology and pathogenesis of prosthetic joint infection due to S lugdunensis and delineates optimal medical and surgical therapies.

Relevance of Influenza A Virus Detection by PCR, Shell Vial Assay, and Tube Cell Culture to Rapid Reporting Procedures

ABSTRACT Influenza A virus was detected at higher rates and for more extended time periods with real-time PCR than with cell cultures. We show here that, using the theranostic approach, rapid viral detection and reporting can provide for early implementation and assessment of available antiviral therapy.

Should National Standards for Reporting Surgical Site Infections Distinguish between Primary and Revision Orthopedic Surgeries

OBJECTIVE To compare the surgical site infection (SSI) rate after primary total hip arthroplasty with the SSI rate after revision total hip arthroplasty. DESIGN Retrospective cohort study. SETTING Mayo Clinic in Rochester, Minnesota, a referral orthopedic center. PATIENTS All patients undergoing primary total hip arthroplasty or revision total hip arthroplasty during the period from January 1, 2002, through December 31, 2006. METHODS We obtained data on total hip arthroplasties from a prospectively maintained institutional surgical database. We reviewed data on SSIs collected prospectively as part of routine infection control surveillance, using the criteria of the Centers for Disease Control and Prevention for the definition of an SSI. We used logistic regression analyses to evaluate differences between the SSI rate after primary total hip arthroplasty and the SSI rate after revision total hip arthroplasty. RESULTS A total of 5,696 total hip arthroplasties (with type 1 wound classification) were analyzed, of which 1,381 (24%) were revisions. A total of 61 SSIs occurred, resulting in an overall SSI rate of 1.1% for all total hip arthroplasties. When stratified by the National Nosocomial Infection Surveillance (NNIS) risk index, SSI rates were 0.5%, 1.2%, and 1.6% in risk categories 0, 1, and 2, respectively. After controlling for the NNIS risk index, the risk of SSI after revision total hip arthroplasty was twice as high as that after primary total hip arthroplasty (odds ratio, 2.2 [95% confidence interval, 1.3-3.7]). In the analysis restricted to the development of deep incisional or organ space infections, the risk of SSI after revision total hip arthroplasty was nearly 4 times that after primary total hip arthroplasty (odds ratio, 3.9 [95% confidence interval, 2.0-7.6]). CONCLUSION Including revision surgeries in the calculation of SSI rates can result in higher infection rates for institutions that perform a larger number of revisions. Taking NNIS risk indices into account does not eliminate this effect. Differences between primary and revision surgeries should be considered in national standards for the reporting of SSIs.

Incidence of Infectious Complications After an Ultrasound-Guided Intervention

OBJECTIVE The objective of our study was to determine the incidence of infectious complications of common ultrasound-guided procedures including fine-needle aspiration (FNA), drain placement, biopsy, pseudoaneurysm thrombin injection, thoracentesis, and paracentesis. SUBJECTS AND METHODS The infection prevention and control (IPAC) committee at the Mayo Clinic, Rochester, MN, conducts surveillance of selected infections including radiology procedures. When a positive culture, hospital admission, or operating room visit for infection is identified, the patients electronic records are thoroughly reviewed by an infection control practitioner looking for information about prior interventions. Similarly, the department of radiology prospectively follows all patients who have undergone ultrasound-guided hepatic, renal, and pancreatic biopsies for complications 24 hours, 3 months, and 12 months after biopsy. We reviewed 2 years of these data to determine the incidence of infections after common ultrasound-guided procedures. RESULTS We performed 13,534 ultrasound-guided procedures from January 2006 to December 2007. There were 11 likely and three possible procedure-related infections for an overall incidence of 0.1% (14/13,534). The infections consisted of five abscesses, four bloodstream infections, four cases of peritonitis, and one urinary tract infection. The highest incidence of infections occurred after ultrasound-guided biopsy (0.2%, 10/5,487), with biopsy of a hepatic transplant having the highest incidence (1.0%, 2/192). No infections occurred after thoracentesis and FNA despite the large number of procedures performed (2,489 and 2,340, respectively). Nearly all patients improved on antibiotics. One patient died 5 days after paracentesis; however, death was likely due to multiorgan failure in the setting of fulminant liver failure with hepatorenal syndrome. CONCLUSION The incidence of a serious infectious complication after ultrasoundguided intervention is low. Radiologists can use these data to provide more accurate information to patients when asking for consent before procedures and to reassure their patients.

Epidemiology and Control of Pertussis Outbreaks in a Tertiary Care Center and the Resource Consumption Associated With These Outbreaks

OBJECTIVE To describe the epidemiology and control of 2 separate outbreaks of pertussis at a large tertiary care center and the resource consumption associated with these outbreaks. DESIGN Descriptive study. SETTING The Mayo Clinic in Rochester, Minnesota, a tertiary care center catering to both referral patients and patients from the community. METHODS We reviewed routine and enhanced surveillance data collected by infection prevention and control practitioners during the outbreaks. Pertussis was diagnosed either on the basis of a nasopharyngeal specimen positive for Bordetella pertussis by use of polymerase chain reaction (PCR) or on the basis of a compatible clinical syndrome along with an epidemiologic link to PCR-confirmed cases. RESULTS Two pertussis outbreaks, the first community based and the second hospital based (ie, due to transmission among healthcare personnel), occurred during the period from October 2004 through October 2005. In the first outbreak from November 2004 through March 2005, there were 109 cases diagnosed; 105 (96%) of these cases were diagnosed on the basis of a nasopharyngeal specimen positive for B. pertussis by use of PCR. Adolescents 10-19 years of age were most affected (77 cases [71%]). Only 13 cases (12%) occurred among healthcare personnel; however, many healthcare personnel required postexposure prophylaxis. A second outbreak of 122 cases occurred during the period from July through October 2005; of these 122 cases, 96 (79%) were diagnosed on the basis of a nasopharyngeal specimen positive for B. pertussis by use of PCR, and 64 (52%) involved healthcare personnel. There were many instances of transmission among healthcare personnel and from patients to healthcare personnel, but no documented transmission from healthcare personnel to patients. The outbreaks were controlled by aggressive case finding, treatment of those infected, prophylaxis of all healthcare personnel and patients who had contact with both probable and confirmed cases, implementation of educational efforts, and compliance with respiratory etiquette. Vaccination of healthcare personnel against pertussis began in October 2005. CONCLUSION Pertussis remains a public health problem. Outbreaks in healthcare facilities consume the resources of those facilities in terms of personnel, testing, treatment of cases, and prophylaxis of those individuals who were in contact with those cases. Adult vaccination may reduce the disease burden.

Disseminated Mycobacterium chimaera Infection After Cardiothoracic Surgery

Ten case reports of disseminated Mycobacterium chimaera infections associated with cardiovascular surgery were published from Europe. We report 3 cases of disseminated M chimaera infections with histories of aortic graft and/or valvular surgery within the United States. Two of 3 patients demonstrated ocular involvement, a potentially important clinical finding.