John M. Townes

Health care-associated invasive MRSA infections, 2005-2008.

CONTEXT Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen of public health importance; MRSA prevention programs that may affect MRSA transmission and infection are increasingly common in health care settings. Whether there have been changes in MRSA infection incidence as these programs become established is unknown; however, recent data have shown that rates of MRSA bloodstream infections (BSIs) in intensive care units are decreasing. OBJECTIVE To describe changes in rates of invasive health care-associated MRSA infections from 2005 through 2008 among residents of 9 US metropolitan areas. DESIGN, SETTING, AND PARTICIPANTS Active, population-based surveillance for invasive MRSA in 9 metropolitan areas covering a population of approximately 15 million persons. All reports of laboratory-identified episodes of invasive (from a normally sterile body site) MRSA infections from 2005 through 2008 were evaluated and classified based on the setting of the positive culture and the presence or absence of health care exposures. Health care-associated infections (ie, hospital-onset and health care-associated community-onset), which made up 82% of the total infections, were included in this analysis. MAIN OUTCOME MEASURES Change in incidence of invasive health care-associated MRSA infections and health care-associated MRSA BSIs using population of the catchment area as the denominator. RESULTS From 2005 through 2008, there were 21,503 episodes of invasive MRSA infection; 17,508 were health care associated. Of these, 15,458 were MRSA BSIs. The incidence rate of hospital-onset invasive MRSA infections was 1.02 per 10,000 population in 2005 and decreased 9.4% per year (95% confidence interval [CI], 14.7% to 3.8%; P = .005), and the incidence of health care-associated community-onset infections was 2.20 per 10,000 population in 2005 and decreased 5.7% per year (95% CI, 9.7% to 1.6%; P = .01). The decrease was most prominent for the subset of infections with BSIs (hospital-onset: -11.2%; 95% CI -15.9% to -6.3%; health care-associated community-onset: -6.6%; 95% CI -9.5% to -3.7%). CONCLUSION Over the 4-year period from 2005 through 2008 in 9 diverse metropolitan areas, rates of invasive health care-associated MRSA infections decreased among patients with health care-associated infections that began in the community and also decreased among those with hospital-onset invasive disease.

National burden of invasive methicillin-resistant Staphylococcus aureus infections, United States, 2011.

IMPORTANCE Estimating the US burden of methicillin-resistant Staphylococcus aureus (MRSA) infections is important for planning and tracking success of prevention strategies. OBJECTIVE To describe updated national estimates and characteristics of health care- and community-associated invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in 2011. DESIGN, SETTING, AND PARTICIPANTS Active laboratory-based case finding identified MRSA cultures in 9 US metropolitan areas from 2005 through 2011. Invasive infections (MRSA cultured from normally sterile body sites) were classified as health care-associated community-onset (HACO) infections (cultured ≤ 3 days after admission and/or prior year dialysis, hospitalization, surgery, long-term care residence, or central vascular catheter presence ≤ 2 days before culture); hospital-onset infections (cultured >3 days after admission); or community-associated infections if no other criteria were met. National estimates were adjusted using US census and US Renal Data System data. MAIN OUTCOMES AND MEASURES National estimates of invasive HACO, hospital-onset, and community-associated MRSA infections using US census and US Renal Data System data as the denominator. RESULTS An estimated 80,461 (95% CI, 69,515-93,914) invasive MRSA infections occurred nationally in 2011. Of these, 48,353 (95% CI, 40,195-58,642) were HACO infections; 14,156 (95% CI, 10,096-20,440) were hospital-onset infections; and 16,560 (95% CI, 12,806-21,811) were community-associated infections. Since 2005, adjusted national estimated incidence rates decreased among HACO infections by 27.7% and hospital-onset infections decreased by 54.2%; community-associated infections decreased by only 5.0%. Among recently hospitalized community-onset (nondialysis) infections, 64% occurred 3 months or less after discharge, and 32% of these were admitted from long-term care facilities. CONCLUSIONS AND RELEVANCE An estimated 30,800 fewer invasive MRSA infections occurred in the United States in 2011 compared with 2005; in 2011 fewer infections occurred among patients during hospitalization than among persons in the community without recent health care exposures. Effective strategies for preventing infections outside acute care settings will have the greatest impact on further reducing invasive MRSA infections nationally.

Characterization of Methicillin-Resistant Staphylococcus aureus Isolates Collected in 2005 and 2006 from Patients with Invasive Disease: a Population-Based Analysis

ABSTRACT This study characterizes 1,984 methicillin-resistant Staphylococcus aureus (MRSA) isolates collected in 2005 and 2006 from normally sterile sites in patients with invasive MRSA infection. These isolates represent a convenience sample of all invasive MRSA cases reported as part of the Active Bacterial Core surveillance system in eight states in the United States. The majority of isolates were from blood (83.8%), joints (4.1%), and bone (4.2%). Isolates were characterized by pulsed-field gel electrophoresis (PFGE); SCCmec typing; susceptibility to 15 antimicrobial agents; and PCR analysis of staphylococcal enterotoxin A (SEA) to SEH, toxic shock syndrome toxin 1, and Panton-Valentine leukocidin. Thirteen established PFGE types were recognized among these isolates, although USA100 and USA300 predominated, accounting for 53.2% and 31.4% of the isolates, respectively. As expected, isolates from hospital onset cases were predominantly USA100, whereas those from community-associated cases were predominantly USA300. USA100 isolates were diverse (Simpsons discriminatory index [DI] = 0.924); generally positive only for enterotoxin D (74.5%); and resistant to clindamycin (98.6%), erythromycin (99.0%), and levofloxacin (99.6%), in addition to β-lactam agents. USA300 isolates were less diverse (DI = 0.566), positive for Panton-Valentine leukocidin (96.3%), and resistant to erythromycin (94.1%) and, less commonly, levofloxacin (54.6%), in addition to β-lactam agents. This collection provides a reference collection of MRSA isolates associated with invasive disease, collected in 2005 and 2006 in the United States, for future comparison and ongoing studies.

Reactive arthritis following culture-confirmed infections with bacterial enteric pathogens in Minnesota and Oregon: a population-based study

Objective: To describe the epidemiology and clinical spectrum of reactive arthritis (ReA) following culture-confirmed infection with bacterial enteric pathogens in a population-based study in the USA. Methods: We conducted telephone interviews of persons age >1 year with culture confirmed Campylobacter, Escherichia coli O157, Salmonella, Shigella and Yersinia infections reported to FoodNet (http://www.cdc.gov/FoodNet/) in Minnesota, USA and Oregon, USA between 2002 and 2004. Subjects with new onset joint pain, joint swelling, back pain, heel pain and morning stiffness lasting ⩾3 days within 8 weeks of culture (possible ReA) were invited to complete a detailed questionnaire and physical examination. Results: A total of 6379 culture-confirmed infections were reported; 70% completed screening interviews. Of these, 575 (13%) developed possible ReA; incidence was highest following Campylobacter (2.1/100 000) and Salmonella (1.4/100 000) infections. Risk was greater for females (relative risk (RR) 1.5, 95% CI, 1.3 to 1.7), adults (RR 2.5, 95% CI, 2.0 to 3.1) and subjects with severe acute illness (eg, fever, chills, headache, persistent diarrhoea). Risk was not associated with antibiotic use or human leukocyte antigen (HLA)-B27. A total of 54 (66%) of 82 subjects examined had confirmed ReA. Enthesitis was the most frequent finding; arthritis was less common. The estimated incidence of ReA following culture-confirmed Campylobacter, E coli O157, Salmonella, Shigella and Yersinia infections in Oregon was 0.6–3.1 cases/100 000. Conclusions: This is the first population-based study of ReA following infections due to bacterial enteric pathogens in the USA. These data will help determine the burden of illness due to these pathogens and inform clinicians about potential sequelae of these infections.

Trends in Invasive Methicillin-Resistant Staphylococcus aureus Infections

OBJECTIVE: To describe trends in the incidence of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in children during 2005–2010. METHODS: We evaluated reports of invasive MRSA infections in pediatric patients identified from population-based surveillance during 2005–2010. Cases were defined as isolation of MRSA from a normally sterile site and classified on the basis of the setting of the positive culture and presence or absence of health care exposures. Estimated annual changes in incidence were determined by using regression models. National age- and race-specific incidences for 2010 were estimated by using US census data. RESULTS: A total of 876 pediatric cases were reported; 340 (39%) were among infants. Overall, 35% of cases were hospital-onset, 23% were health care–associated community-onset, and 42% were community-associated (CA). The incidence of invasive CA-MRSA infection per 100 000 children increased from 1.1 in 2005 to 1.7 in 2010 (modeled yearly increase: 10.2%; 95% confidence interval: 2.7%–18.2%). No significant trends were observed for health care–associated community-onset and hospital-onset cases. Nationally, estimated invasive MRSA incidence in 2010 was higher among infants aged <90 days compared with older infants and children (43.9 vs 2.0 per 100 000) and among black children compared with other races (6.7 vs 1.6 per 100 000). CONCLUSIONS: Invasive MRSA infection in children disproportionately affects young infants and black children. In contrast to reports of declining incidence among adults, there were no significant reductions in health care–associated MRSA infections in children. Concurrently, the incidence of CA-MRSA infections has increased, underscoring the need for defining optimal strategies to prevent MRSA infections among children with and without health care exposures.

An Outbreak of Type A Botulism Associated with a Commercial Cheese Sauce

Botulism is a rare disease; between 1983 and 1992, an average of only 22 cases of food-borne botulism were reported to the Centers for Disease Control and Prevention each year (Unpublished data). Nevertheless, a reported case of food-borne botulism represents a public health emergency because many persons may be affected if the contaminated food is not identified. This is especially true of outbreaks linked to commercial products or restaurants. However, because few clinicians have ever seen a case of botulism, the diagnosis may be delayed or not even considered. Diagnosing botulism is a special challenge when patients present with mild symptoms and do not have a history of exposure to typical food vehicles, such as home-canned vegetables. We describe an outbreak of botulism that was characterized by relatively mild symptoms and subtle physical findings. The outbreak was caused by a food vehicle that was initially considered to be unlikely. The investigation shows the importance of considering the diagnosis of botulism soon after patients present with acute cranial nerve dysfunction and of promptly reporting suspected cases to public health officials. The Outbreak On 4 October 1993, a 42-year-old woman (patient 1) visited her family physician in a small town in southern Georgia. She had had nausea, blurred vision, and loss of balance for 2 days. Results of physical examination were normal except for a possible sixth-nerve palsy. Labyrinthitis was diagnosed, and the patient was sent home. When her physician contacted her the next day, she was too weak to come to the telephone. Her husband reported that her speech was slurred and that she was having difficulty swallowing. He mentioned that their 21-year-old daughter (patient 2) also had nausea and difficulty swallowing. Both patients were referred to a neurologist, who recognized this unusual clustering of neurologic symptoms as possible botulism. The patients were admitted to a hospital, and public health officials were notified. That same day, a 38-year-old woman with a history of hypertension (patient 3) was seen in the emergency department of the same hospital because of blurred vision, slurred speech, and weakness in her right arm. She was admitted to the medical ward with a diagnosis of transient ischemic attack. By coincidence, the family physician of patients 1 and 2 was also attending on the medical ward that night; he recognized that patient 3 might be another case of botulism. Patient 3 mentioned that her friend, patient 4, was having similar symptoms. Patient 4 was notified that her illness might also be botulism, and she too was hospitalized. Two days earlier, her new symptoms had been diagnosed as an allergic reaction to a tranquilizer. Patient 5 had visited an optometrist on 5 October with fatigue and blurred, double vision. She received a diagnosis of mild glaucoma and astigmatism and was given a prescription for eyeglasses. She presented to the emergency department on 7 October after hearing about the outbreak on the radio. None of the patients had eaten any home-canned foods. However, on 1 October, all of them had eaten food from a delicatessen that had re-opened on 23 September after having been closed for 6 months because of the owners family obligations. Local health officials closed the delicatessen on 6 October and seized leftover foods. Methods Clinical and Epidemiologic Investigation Hypothesis-generating interviews were done with the hospitalized patients and the owner of the delicatessen. Each step in the preparation and storage of foods was reviewed. After a standardized questionnaire that addressed food histories and symptoms was developed, investigators attempted to interview (either by telephone or in person) all persons who had eaten food from the delicatessen in the 6 days it was open between 23 September and 2 October 1993. For the purposes of the investigation, a case of botulism was defined as dysphagia, dysphonia, dysarthria, or diplopia that developed after 23 September in any person who had eaten food purchased at the delicatessen. A press release was issued to identify patrons of the delicatessen. The press release asked all persons who had eaten at the delicatessen to call the local health department. The owner and known patrons of the delicatessen were asked to name other patrons, and businesses in the neighborhood around the delicatessen were surveyed as to whether workers had eaten food from the delicatessen. In an attempt to find additional cases, 50 physicians in the area were called and asked whether they had seen any patients since 23 September who reported blurred or double vision, dry mouth, difficulty swallowing, change in voice, or muscle weakness. To identify any cases that may have been mistakenly diagnosed as other conditions, physicians were also asked if they had recently seen any patients with a diagnosis of stroke, transient ischemic attack, the Guillain-Barre syndrome, or myasthenia gravis. Logs from the emergency department of the local hospital were reviewed for these symptoms and diagnoses. All hospitalized patients were examined by the same neurologist, and their hospital and outpatient records were reviewed. No neurologic examination was done on three persons who met the case definition for botulism but did not seek medical attention. These patients were identified by their responses to the standard questionnaire. The delicatessen was inspected by officials of the Georgia Department of Agriculture. Officials of the Food and Drug Administration inspected the canning facility and searched for unused cans of the same batch of cheese sauce. Laboratory Investigation Samples of food taken from the delicatessen were assayed for botulinum toxin and were cultured for Clostridium botulinum as described elsewhere [1]. All persons who ate the implicated food were asked to submit serum and stool specimens. Gastric aspirate specimens were obtained from two hospitalized patients. Serum, stool, and gastric aspirate specimens were assayed for C. botulinum toxin, and stool specimens were cultured for C. botulinum. Inoculation experiments were done in the Food and Drug Administration botulism laboratory to determine the time and temperature needed for C. botulinum to grow and for toxin to be produced in the implicated brand of cheese sauce. Spores harvested from cultures of the outbreak strain of C. botulinum were heat-shocked at 80 C for 10 minutes and then diluted with sterile water to a concentration of 104 spores/mL. Twenty g of the cheese sauce was then added to sterile test tubes that contained 0.1 mL of inoculum; the final concentration was 103 spores/20 g of cheese. The tubes were incubated at 22 C and 5 C; they were then assayed for toxin on day 8 and every 3 to 4 days for 2 months. Toxin testing was also done before incubation to ensure that no toxin was transferred with the inoculum. Toxin was measured in mouse minimum lethal doses using the mouse bioassay [2]. Results Epidemiologic Findings The delicatessen first opened in August 1992 and then closed for 6 months from March to September 1993. It reopened on 23 September 1993, serving lunch 3 days a week (Thursday through Saturday). Food was served at the delicatessen from 23 to 25 September and from 30 September to 2 October (Figure 1). Routine inspections of the delicatessen done on 30 September and after the outbreak showed no violations of state standards for retail food sale establishments. Figure 1. Date of meals eaten by all 52 patrons of the delicatessen and dates of symptom onset in 8 patrons with botulism. Fifty-two persons who ate food from the delicatessen in the 6 days it was open between 23 September and 2 October 1993 were identified and interviewed. Eight (15%) met the case definition for botulism. Their ages ranged from 20 to 48 years; 6 were women. No additional cases were identified through the review of emergency department logs or the physician survey. The owner of the delicatessen estimated that she served about 20 meals each day. Many of the patrons were friends of the owner or members of the owners family and had eaten there more than once. Eight (36%) of 22 persons who ate food from the delicatessen on Friday, 1 October, met the case definition compared with none of the 30 who ate the food only on other days. Among the 22 persons who ate food from the delicatessen on 1 October, all 8 ill persons but none of 14 well persons had eaten a barbecue stuffed potato. Six other persons had eaten barbecue stuffed potatoes before 1 October but remained well. The owner did not recall selling any stuffed potatoes on 2 October. Clinical Findings and Laboratory Confirmation of Botulism The illnesses ranged from mild to severe. Most patients had few, subtle objective neurologic findings despite having many symptoms characteristic of botulism. Symptoms developed a median of 2.5 days after exposure (range, 1 to 6 days). All ill persons had 3 or more symptoms consistent with botulism (median, 8.5 symptoms; range, 3 to 14 symptoms) and, by definition, at least 1 symptom that suggested a cranial nerve abnormality. The most common symptoms were dry mouth, difficulty speaking and swallowing, and change in voice quality (Table 1). All ill persons had neurologic and gastrointestinal symptoms. Three persons had illnesses so mild that they did not seek medical care. Five persons were hospitalized in an intensive care unit after botulism was suspected; in four of these persons, an illness other than botulism was initially diagnosed (Table 2). Patient 3, the most severely affected, developed complete bilateral ptosis, markedly dysarthric speech, weakness of the tongue and palate, arm and leg weakness, and respiratory failure. She died of a pulmonary embolism after being supported by mechanical ventilation for 18 days. Patient 1 was noticeably dysarthric and required nasogastric intubation because of difficulty swallowing. Patients 2, 4, and 5 had few object

Survey of Physician Diagnostic Practices for Patients with Acute Diarrhea: Clinical and Public Health Implications

To understand physician practices regarding the diagnosis of acute diarrheal diseases, we conducted a survey, in 1996, of 2839 physicians in Connecticut, Georgia, Minnesota, Oregon, and California. Bacterial stool culture was requested for samples from the last patient seen for acute diarrhea by 784 (44%; 95% confidence interval, 42%-46%) of 1783 physicians. Physicians were more likely to request a culture for persons with acquired immune deficiency syndrome, bloody stools, travel to a developing country, diarrhea for >3 days, intravenous rehydration, or fever. Substantial geographic and specialty differences in culture-request practices were observed. Twenty-eight percent of physicians did not know whether stool culture included testing for Escherichia coli O157:H7; 40% did not know whether Yersinia or Vibrio species were included. These variabilities suggest a need for clinical diagnostic guidelines for diarrhea. Many physicians could benefit from education to improve their knowledge about tests included in routine stool examinations.

Neurocysticercosis in Oregon, 1995–2000

The unexpected death of a teenager from neurocysticercosis prompted an investigation of this disease in Oregon. We found 89 hospitalizations, 43 newly diagnosed cases, and 6 deaths from 1995 to 2000. At least five cases occurred in persons who had not traveled or lived outside the United States. Enhanced surveillance for neurocysticercosis is warranted.

Clinical Management of Septic Arthritis

Septic arthritis is a rheumatologic emergency as joint destruction occurs rapidly and can lead to significant morbidity and mortality. Accurate diagnosis can be particularly challenging in patients with underlying inflammatory joint disease. This review outlines the risk factors for septic arthritis and summarizes the causative bacterial organisms. We highlight advances in antibiotic management with a focus on new drugs for methicillin-resistant Staphylococcus aureus (MRSA) and discuss the use of adjunctive therapies for treatment of septic arthritis in adults.

Seroprevalence of antibodies against Taenia solium cysticerci among refugees resettled in United States

Cysticercosis is an infection caused by a pork tapeworm that creates cysts in different areas of the human body. Sometimes, these parasites can get into the infected patient’s brain and lead to epilepsy or other neurologic disorders. Cysticercosis is most common in developing countries that have poor sanitation and where pigs feed on human waste; however, cases in the United States are increasing. A recent study found that many refugees who settle in the United States, including those from Burma, Laos, Burundi, and Bhutan, have been infected with the tapeworm. The occurrence of cysticercosis among these groups has clinical and public health implications because US physicians might not be familiar with this disease and its symptoms. Cysticercosis should be suspected in refugees who have seizures, headache, or other unexplained neurologic symptoms. Physicians should also be aware that treatment for intestinal parasites, routinely given to refugees before they leave their homeland, can cause serious neurologic reactions in those already infected with the tapeworm.