Amanda Wilmer

Incidence of medication errors and adverse drug events in the ICU: a systematic review

Background Medication errors (MEs) and adverse drug events (ADEs) are both common and under-reported in the intensive care setting. The definitions of these terms vary substantially in the literature. Many methods have been used to estimate their incidence. Methods A systematic review was done to assess methods used for tracking unintended drug events in intensive care units (ICUs). Studies published up to 22 June 2007 were identified by searching eight online databases, including Medline. In total, 613 studies were evaluated for inclusion by two reviewers. Results The authors selected 29 papers to analyse; all studies took place in an ICU, were reproducible and reported ICU-specific rates of events. Rates of MEs varied from 8.1 to 2344 per 1000 patient-days, and ADEs from 5.1 to 87.5 per 1000 patient-days. The definitions of ADE and ME in the studies varied widely. Conclusions Much variation exists in reported rates and definitions of ADEs and MEs in ICUs. Some of this variation may be due to a lack of standard definitions for ADEs and MEs, and methods for detecting them. Further standardisation is needed before these methods can be used to evaluate process improvements.

The role of leech water sampling in choice of prophylactic antibiotics in medical leech therapy

Medical leech therapy (MLT) with Hirudo medicinalis is well established as a treatment for venous congestion of tissue flaps, grafts, and replants. Unfortunately, this treatment is associated with surgical site infections with bacterial species, most commonly Aeromonas hydrophila, which is an obligate symbiot of H. medicinalis. For this reason, prophylactic antibiotics are recommended in the setting of MLT. After culturing Aeromonashydrophila resistant to ciprofloxacin from a tissue specimen from a patient with a failed replant of three digits post‐MLT, we performed environmental surveillance cultures and antibiotic susceptibility testing on water collected from leech tanks. This surveillance was performed twice weekly for 2.5 months. Fourteen surveillance cultures demonstrated 21 isolates of Aeromonas species, 71.4% of which were ciprofloxacin susceptible. All isolates were sulfamethoxazole‐trimethoprim (SXT) susceptible. The prophylactic antibiotic regimen of choice for leech therapy at our institution is SXT, with culture of tank water to refine antimicrobial choice if necessary. This study demonstrates the importance of regular surveillance to detect resistant Aeromonas species in medical leeches; however optimal practice has not been established.

Development and Validation of a Pneumocystis jirovecii Real-time Polymerase Chain Reaction Assay for Diagnosis of Pneumocystis Pneumonia

Pneumocystis pneumonia is caused by Pneumocystis jirovecii, an opportunistic fungal pathogen. Presently, many clinical microbiology laboratories rely on direct microscopic detection of P jirovecii. The validation, and clinical and laboratory development of a qualitative P jirovecii real-time polymerase chain reaction assay for the rapid detection of Pneumocystis pneumonia is discussed by the authors. In addition, this new technique is compared with the existing gold-standard immunofluorescence assay.

Shigella flexneri serotype 1 infections in men who have sex with men in Vancouver, Canada.

Outbreaks of shigellosis have been documented in men who have sex with men (MSM), associated with interpersonal transmission and underlying HIV infection. We observed a rise in Shigella flexneri isolates identified in a downtown tertiary‐care hospital laboratory located within the city centre community health area (CHA‐1) of Vancouver, Canada. The objectives of this study were to evaluate clinical outcomes of shigellosis cases among MSM admitted to hospital and to evaluate trends in Shigella cases within Vancouver, Canada.

Intensive nursing work schedules and the risk of hypoglycaemia in critically ill patients who are receiving intravenous insulin

Rationale Nurses in the intensive care unit (ICU) commonly work frequent 12 h shifts, potentially leading to fatigue and reduced vigilance. The authors hypothesised that rates of hypoglycaemia in patients receiving an insulin infusion would be associated with the intensity of work of the bedside nurse in the preceding 72 h. Methods The authors identified ICU patients who had hypoglycaemia (glucose ≤3.5 mmol/l, 63 mg/dl) between October 2006 and June 2007. The number of shifts worked in the previous 72 h was calculated for the nurse caring for the patient when the event occurred (case shift). For each case shift, the authors identified up to three control shifts (24, 48 and 72 h before the event in the same patient) and calculated the number of shifts worked by nurses on these shifts in the previous 72 h. Conditional logistic regression was used to determine whether the number of shifts worked was associated with hypoglycaemia. Results There were 41 events (32 patients). Each additional shift worked in the previous 72 h was associated with a significantly increased risk of hypoglycaemia (OR=1.65/shift, 95% CI 1.01 to 2.68, p=0.04) after controlling for nurse age and experience. The association was greater for the 23 events associated with an error in management according to the insulin protocol (OR=2.93/shift, 1.15 to 7.44, p=0.02) compared with events not associated with an error (OR=1.34/shift, 0.73 to 2.45, p=0.34). Conclusions Intensive nursing work schedules are associated with hypoglycaemic events in ICU patients.

Melioidosis in Trinidad and Tobago

To the Editor: Melioidosis refers to infection caused by the facultative intracellular gram-negative bacterium Burkholderia pseudomallei. The clinical manifestations of melioidosis span a wide spectrum, from asymptomatic exposure or localized cutaneous infection to septic shock with multiorgan failure. Melioidosis usually occurs in residents of or travelers to disease-endemic areas in northern Australia and Southeast Asia; however, an increasing number of confirmed melioidosis cases are being reported from the Caribbean. We report a case of melioidosis acquired in Trinidad and Tobago. In February 2014, a 17-year-old male student was admitted to a tertiary care hospital in Vancouver, British Columbia, Canada, with catecholaminergic polymorphic ventricular tachycardia and electrical storm. He had a 9-month history of dry cough that was unresponsive to multiple and prolonged courses of treatment for community-acquired pneumonia. During the 6 months before his admission, the patient had hemoptysis and radiologic evidence of pneumonia that were treated with courses of cephalosporins without resolution of symptoms. Bronchoscopy and culture of lavage samples had revealed infection with Staphylococcus aureus and an organism most closely related to Actinomyces graevenitzii . The patient had no history indicative of risk factors for recurrent sinusitis or pneumonia (e.g., cystic fibrosis, chronic granulatomous disease, Job syndrome), and no risk factors for tuberculosis or infection with dimorphic fungi. He was up to date on his vaccinations and had no pets. He was born in Jamaica, had moved to Canada at age 4, and had not traveled anywhere other than Trinidad and Tobago, Canada, and England. He had traveled to visit family in Trinidad for 2 months during the rainy season in 2012, at which time he also visited Tobago. On day 5 of hospital admission, the patient became febrile (39.6°C), and an infectious diseases specialist was consulted. Examination revealed that the patient was clinically stable but emaciated at 45 kg. His oxygen saturation while breathing room air was 98%. Physical examination, including cardiorespiratory examination, was unremarkable. Laboratory results showed a normal hemoglobin concentration of 133 g/L; elevated leukocyte count of 22.8 × 109 cells/L; neutrophils 19.4 × 109 cells/L; normal platelet count of 295 × 109/L; and normal creatinine of 54 μmol/L. Test results for HIV-1 and blood cultures were negative. Computed tomography scan showed dilated bronchi and dense consolidation of the right and left lower lobes. Piperacillin/tazobactam was started for presumed hospital-acquired pneumonia. The patient underwent diagnostic bronchoscopy with bronchoalveolar lavage. Gram staining of specimens showed occasional gram-negative bacilli, and aerobic cultures grew gram-negative bacilli. Further testing with the Vitek 2 (bioMerieux, Laval, Quebec, Canada) (96%) and RapID NF (Oxoid, Nepean, Ontario, Canada) (99.9%) systems identified B. pseudomallei, but matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (Vitek MS, bioMerieux) did not. Phenotypic confirmation was performed at the provincial public health and reference laboratory. Antimicrobial drug susceptibility testing performed by broth microdilution according to Clinical and Laboratory Standards Institute recommendations (1) and by Etest (bioMerieux) showed susceptibility to amoxicillin/clavulanic acid, ceftazidime, imipenem, doxycycline, and trimethoprim/sulfamethoxazole. The patient’s condition improved after 2 weeks of intravenous meropenem, and antimicrobial therapy was changed to oral trimethoprim/sulfamethoxazole. The B. pseudomallei isolate was sent to the Public Health Agency of Canada’s National Microbiology Laboratory for molecular typing. Query of 7 standard multilocus sequence typing loci (http://bpseudomallei.mlst.net/) identified the isolate as a novel multilocus sequence type. The sequence type (1,1,2,1,5,6,1) closely resembled that of B. pseudomallei previously isolated from the Caribbean (2). Although melioidosis was first described in the Caribbean in 1947 (3), most case reports of the disease in the area are from the past 2 decades. This case report suggests progression of the range of melioidosis to include Trinidad and Tobago. A recent study documented the presence of B. pseudomallei in soil samples and high seroprevalence rates among contacts of persons with melioidosis in Puerto Rico (4). If examined, this pattern of regional melioidosis endemicity may also be found on other Caribbean islands. Increased clinical awareness of and improved surveillance for B. pseudomallei infection may partly explain emergence. Nonetheless, underascertainment probably occurs in rural areas with limited access to advanced diagnostic support and in urban areas when B. pseudomallei infection is not suspected because of lack of travel to classic disease-endemic areas. Because B. pseudomallei is a Biosafety Level 3 agent, when infectious disease specialists consider melioidosis in their differential diagnoses, they should alert the microbiology laboratory to confirm species identification and ensure that staff use proper biosafety measures. A total of 19 cases of melioidosis acquired in the Caribbean have been reported (Table). Nine of these were travel related, suggesting that melioidoisis may be emerging as a travel health issue. Travelers with known risk factors for melioidosis, such as diabetes mellitus and chronic lung disease, should be informed of their increased infection risk. Physicians should include B. pseudomallei in the differential diagnosis of travelers with pneumonia or sepsis who are returning from the Caribbean, particularly when they have a history of travel during the rainy season, soil-contaminated wounds, or known risk factors for melioidosis. Table Published case reports of melioidosis from the Caribbean*

Reduction in community-onset methicillin-resistant Staphylococcus aureus rates in an urban Canadian hospital setting.

Community-onset methicillin resistant Staphylococcus aureus (CO-MRSA) became a prominent cause of infection in North America in 2003, with a peak in the epidemic noted by multiple groups in the USA between 2005 and 2007. We reviewed rates of MRSA in two hospitals in Vancouver, Canada, to observe changes in epidemiology from 2003 to 2011. Episodes of emergency department (ED) MRSA bacteraemia and wounds were extracted from the laboratory database, with rates calculated per 10,000 ED visits. All cases were assumed to be community onset, as they were diagnosed in the ED. A peak in ED MRSA bacteraemias occurred in 2005, at 7·8/10,000 ED visits. By 2011, rates of ED bacteraemia declined significantly to 3·3/10,000 ED visits (P<or=0·03). MRSA wound rates peaked at 82·2 cases/10,000 ED visits in 2007 with a subsequent significant decline to 34·3 cases in 2011 (P=0·04). We have demonstrated a significant decline in CO-MRSA within our population, consistent with reports from the USA, suggesting a substantial change in the epidemiology of CO-MRSA in certain North American cities.

Polymerase chain reaction assay to detect Clostridium difficile tcdC variants is valuable in characterizing hospital epidemiology

The epidemiology of nosocomial Clostridium difficile infection (CDI), acquired at two hospitals in Vancouver over a one-year period, was reviewed. Cases were analysed by tcdC polymerase chain reaction, with tcdC variants (18 base pair deletion) highly associated with the NAP1 strain. Of the 214 cases identified, 51.9% were caused by these tcdC variants; these cases occurred more frequently in older patients admitted to the community hospital where the strain was endemic. Overall, at least five out of 24 cases classified as recurrences by surveillance definitions were reinfections. Molecular testing allowed identification of major epidemiological differences between the hospitals studied and provided more accurate classification of CDI cases.