Identification of a novel metallo-ß-lactamase, CAM-1, in clinical Pseudomonas aeruginosa isolates from Canada.

OBJECTIVES: To identify the ß-lactamase responsible for the positive detection of carbapenemase production in four clinical isolates of Pseudomonas aeruginosa that were negative by PCR for KPC, OXA-48, NDM, VIM, IMP, GES and NMC/IMI carbapenemase genes. METHODS: WGS using short-read and long-read methods was used to characterize the isolates. Bioinformatic analysis was used to identify the potential gene encoding a carbapenemase. Cloning, antimicrobial susceptibility testing and biochemical and phenotypic characterization were used to determine metallo-enzyme activity. Single-nucleotide variant (SNV) typing was used to determine strain relatedness. Conjugation experiments were used to determine transmissibility of the novel carbapenemase-encoding gene. RESULTS: WGS analysis revealed a novel class B ß-lactamase gene, blaCAM-1 (Central Alberta Metallo-ß-lactamase), located in a 73 kb integrative element, named IMEPaCAM-1, in the chromosome of four clinical isolates of P. aeruginosa. The cloned blaCAM-1 gene conferred carbapenem resistance to Escherichia coli TOP10. The four isolates, which were all closely related, were from three patients, all of whom spent time in the same hospital in 2008 and/or 2009. IMEPaCAM-1 could not be transferred by conjugation. CONCLUSIONS: A novel metallo-enzyme, CAM-1, is encoded on an integrative element, IMEPaCAM-1, located in the chromosome of clinical isolates of P. aeruginosa. No additional isolates harbouring CAM-1 have been identified in Alberta since 2007.

Headache Characteristics in Children With Pseudotumor Cerebri Syndrome, Elevated Opening Pressure Without Papilledema, and Normal Opening Pressure: A Retrospective Cohort Study.

BACKGROUND: Certain headache characteristics and associated symptoms are commonly attributed to increased intracranial pressure, but they have not been systematically studied among children in the context of revised diagnostic criteria for pseudotumor cerebri syndrome (PTCS). METHODS: We performed a retrospective cohort study of patients treated for suspected or confirmed PTCS. Charts were reviewed for PTCS and headache diagnostic criteria and associated characteristics. Chi-squared or Fisher's exact tests were used to compare the frequency of headache characteristics between groups. RESULTS: One hundred and twenty-seven individuals were identified: 61 had definite PTCS, 10 had probable PTCS, 31 had elevated opening pressure (OP) without papilledema, and 25 had normal OP without papilledema. Eleven children had no headache (6 with definite PTCS, 5 with probable PTCS). Headache pattern was episodic in 49% (95% CI: 34-64%) of those with definite PTCS, 18% (95% CI 6-37%) of those with elevated OP without papilledema, and 16% (5-36%) of those with normal OP without papilledema. Headache location was more likely to involve the head along with neck or shoulders in those with definite PTCS compared with elevated OP without papilledema (OR = 7.2, 95% CI: 1.9-27.6) and normal OP (OR = 4.5, 95% CI: 1.3-15.6) groups. DISCUSSION: While missing data and small cohort size are limitations, this study suggests that headache in PTCS is more likely to involve the head along with neck/shoulders, and that headache in PTCS may be episodic or constant. Headache is occasionally absent in PTCS.

Infections Caused by Actinomyces neuii: A Case Series and Review of an Unusual Bacterium.

Background. Actinomyces neuii is a Gram-positive bacillus rarely implicated in human infections. However, its occurrence is being increasingly recognized with the use of improved identification systems. Objective. To analyse A. neuii infections in Alberta, Canada, and review the literature regarding this unusual pathogen. Methods. Cases of A. neuii were identified in 2013-2014 in Alberta. Samples were cultured aerobically and anaerobically. A predominant catalase positive Gram-positive coryneform bacillus with no branching was isolated in each case. Testing was initially done with API-CORYNE® (bioMérieux) and isolates were sent to the Provincial Laboratory for Public Health for further testing. Isolates' identities were confirmed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry microbial identification system (MALDI-TOF MS MIS; bioMérieux) and/or DNA sequencing. Results. Six cases of A. neuii infection were identified. All patients had soft tissue infections; typically, incision and drainage were done followed by a course of antibiotics. Agents used included cephalexin, ertapenem, ciprofloxacin, and clindamycin. All had favourable outcomes. Conclusions. While A. neuii is infrequently recognized, it can cause a diverse array of infections. Increased use of MALDI-TOF MS MIS is leading to increased detection; thus, understanding the pathogenicity of this bacterium and its typical susceptibility profile will aid clinical decision-making.

Global analysis of the evolution and mechanism of echinocandin resistance in Candida glabrata.

The evolution of drug resistance has a profound impact on human health. Candida glabrata is a leading human fungal pathogen that can rapidly evolve resistance to echinocandins, which target cell wall biosynthesis and are front-line therapeutics for Candida infections. Here, we provide the first global analysis of mutations accompanying the evolution of fungal drug resistance in a human host utilizing a series of C. glabrata isolates that evolved echinocandin resistance in a patient treated with the echinocandin caspofungin for recurring bloodstream candidemia. Whole genome sequencing identified a mutation in the drug target, FKS2, accompanying a major resistance increase, and 8 additional non-synonymous mutations. The FKS2-T1987C mutation was sufficient for echinocandin resistance, and associated with a fitness cost that was mitigated with further evolution, observed in vitro and in a murine model of systemic candidemia. A CDC6-A511G(K171E) mutation acquired before FKS2-T1987C(S663P), conferred a small resistance increase. Elevated dosage of CDC55, which acquired a C463T(P155S) mutation after FKS2-T1987C(S663P), ameliorated fitness. To discover strategies to abrogate echinocandin resistance, we focused on the molecular chaperone Hsp90 and downstream effector calcineurin. Genetic or pharmacological compromise of Hsp90 or calcineurin function reduced basal tolerance and resistance. Hsp90 and calcineurin were required for caspofungin-dependent FKS2 induction, providing a mechanism governing echinocandin resistance. A mitochondrial respiration-defective petite mutant in the series revealed that the petite phenotype does not confer echinocandin resistance, but renders strains refractory to synergy between echinocandins and Hsp90 or calcineurin inhibitors. The kidneys of mice infected with the petite mutant were sterile, while those infected with the HSP90-repressible strain had reduced fungal burden. We provide the first global view of mutations accompanying the evolution of fungal drug resistance in a human host, implicate the premier compensatory mutation mitigating the cost of echinocandin resistance, and suggest a new mechanism of echinocandin resistance with broad therapeutic potential.

Effects of breakpoint changes on carbapenem susceptibility rates of Enterobacteriaceae: Results from the SENTRY Antimicrobial Surveillance Program, United States, 2008 to 2012.

In the absence of clinical resistance, breakpoints for many antimicrobial agents are often set high. Clinical failures following use of the agents over time requires re-evaluation of breakpoints. This is based on patient response, pharmacokinetic/pharmacodynamic information and in vitro minimal inhibitory concentration data. Data from the SENTRY Antimicrobial Surveillance Program has shown that Clinical and Laboratory Standards Institute breakpoint changes for carbapenems that occurred between 2008 and 2012 in North America have resulted in decreased levels of susceptibility for some species. In particular, reduced susceptibility to imipenem was observed for Proteus mirabilis (35%) and Morganella morganii (80%). Minor decreases in susceptibility were also noted for Enterobacter species with ertapenem (5%) and imipenem (4.3%), and Serratia species with imipenem (6.4%). No significant decreases in susceptibility were observed for meropenem following the breakpoint changes. There were no earlier breakpoints established for doripenem. Very few of these Enterobacteriaceae produce carbapenamase enzymes; therefore, the clinical significance of these changes has not yet been clearly determined. In conclusion, ongoing surveillance studies with in vitro minimum inhibitory concentration data are essential in predicting the need for breakpoint changes and in identifying the impact of such changes on the percent susceptibility of different species.

En l'absence de résistance clinique, la résistance de nombreux antimicrobiens est souvent fixée à un seuil élevé. En raison de l'échec clinique de certains de ces médicaments, il faut en réévaluer les seuils de résistance, d'après la réponse du patient, l'information pharmacocinétique et pharmacodynamique et les données relatives à la concentration minimale inhibitrice in vitro. Les données du programme de surveillance antimicrobienne SENTRY ont révélé que les changements au seuil de résistance des carbapénèmes établis par le Clinical and Laboratory Standards Institute entre 2008 et 2012 en Amérique du Nord ont entraîné une diminution de la susceptibilité de certaines espèces. Notamment, les chercheurs ont observé une susceptibilité réduite du Proteus mirabilis (35 %) et du Morganella morganii (80 %) à l'imipénem. Ils ont également remarqué de légères diminutions de la susceptibilité des espèces d'Enterobacter à l'ertapénem (5 %) et à l'imipénem (4,3 %), ainsi que des espèces de Serratia à l'imipénem (6,4 %). La susceptibilité du méropénem n'a pas diminué de manière significative, tandis qu'aucun seuil de résistance n'avait été établi auparavant pour le doripénem. Puisque très peu de ces entérobactériacés produisent des enzymes de carbapénémase, la signification clinique de ces changements n'est pas encore claire. Bref, il est essentiel de poursuivre les études de surveillance pour colliger des données sur les concentrations minimales inhibitrices in vitro afin de prédire la nécessité de changer le seuil de résistance et de déterminer les conséquences de ces changements sur le pourcentage de susceptibilité des diverses espèces.

Preliminary Evidence for the Role of Fungi, Specifically Chaetomium, in Gulf War Illness.

INTRODUCTION: For veterans of the Persian Gulf War (1990-1991), dozens of possible causes for their illness have been proposed. We hypothesize that all may be correct. These may have weakened the immunity of the military personnel to fungal pathogens in the soil. These microbes, in turn, may have afflicted the veterans either directly by infection or indirectly by toxins. MATERIALS AND METHODS: In 1990, the military (source confidential) provided the first author with soil samples from the Persian Gulf to determine if there were biothreats present. His team found that per gram of soil, there had few bacteria but many fungi. The National Centre for Human Mycotic Diseases (Edmonton) identified some of these fungi. They sent to the first author reference cultures of 12 pathogenic fungal species isolated from Canadian patients. Supernatant antigens of these fungi were used to assess if control and Gulf War Illness (GWI) patient sera had IgG antibodies against them. RESULTS: Human sera were tested on pathogenic fungal supernatant antigens. Controls had low IgG titers against all 12 fungal sources. Gulf War Illness (GWI) patient sera had low IgG titers against 11 of the 12 fungal antigens. However, 12 of 28 GWI patient sera (43%, P ≤ .0002 compared to controls) had high IgG titers against one fungus, Chaetomium, supernatant antigen. CONCLUSIONS: We suggest that the military personnel in the Persian Gulf War (1990-1991) may have had their immunity weakened from a variety of causes. The role of pathogenic fungi and/or their supernatant antigens or toxins as a contributing factor to GWI should be further investigated.

Success of Helicobacter pylori Guideline-based Treatment of Newly Diagnosed and Previously Treated Patients During 2007-2021 in Edmonton, Alberta.

Background: Updated 2016 Helicobacter pylori consensus guidelines recommend treatment for 14 days with concomitant therapy (proton-pump inhibitor (PPI)-amoxicillin-metronidazole-clarithromycin (PAMC) or bismuth-based quadruple therapy (PPI-bismuth-metronidazole-tetracycline, PBMT)) as first line, PBMT or PPI-amoxicillin-levofloxacin (PAL) as second or third line, and PPI-amoxicillin-rifabutin (PAR) as fourth line for 10 days. Objectives: This was a retrospective cohort study to describe and compare the efficacy of anti-Helicobacter treatment regimens over the periods 2007-2015 and 2016-2021 as well as antibiotic resistance. Methods: A modified intention-to-treat (mITT) analysis was used to analyze the success rate of therapies. mITT includes all patients who were prescribed H. pylori treatment and had at least one follow-up test-of-cure. This included patients who could not complete treatment or were non-adherent with treatment. Risk factors for treatment failures were analyzed by univariate and multivariate logistic regression. Resistance testing was done in a small subset of patients. Results: H. pylori-positive patients who received treatment in Edmonton, Alberta were included in a mITT analysis: 334/387(86%) from 2007 to 2015 and 193/199 (97%) from 2016 to 2021. During 2016-2021, 78% (150/193) of patients underwent cumulative guideline-based treatment with a successful cure in 80% (120/150) of patients. In those who were newly diagnosed, the cure rate was 88% (52/59) versus those with previous treatment failure 75% (68/91) (P < 0.05, risk difference [RD] 14%, 95% confidence interval [CI] 1.7-26.3%). The most effective first-line regimens were PAMC for 14 days (87% [45/52]) in 2016-2021 and sequential therapy in 2007-2015 (83% [66/80]) (P = 0.535, RD 4%, 95% CI -8.5-16.5%). When other treatments failed, success with PAR was 50% (2/4) from 2007 to 2015 and 57% (21/37) from 2016 to 2021. Recent (2016-2021) resistance rates to clarithromycin and metronidazole are high at 78% (50/64) and 56% (29/52), respectively. From 2007 to 2015, clarithromycin and metronidazole resistance rates were 80% (36/45) and 83% (38/46), respectively. Levofloxacin resistance increased significantly from 2007-2015 to 2016-2021 (28% [13/46] to 61% [35/57], P < 0.05, RD 33%, 95% CI 11.6-54.4%). Conclusions: Algorithmic treatment with PAMC first line followed by PBMT, PAL, and PAR cures H. pylori in 88% of newly diagnosed patients. PAR therapy shows suboptimal cure rates (50-57% success) but can be considered as third instead of fourth line given increasing levofloxacin resistance rates. Antibiotic resistance in H. pylori is common to clarithromycin, metronidazole, and levofloxacin and frequently accounts for treatment failures.

Current and future challenges in the development of antimicrobial agents.

Micro-organisms exist to survive. Even in the absence of antimicrobial agents, many have determinants of resistance that may be expressed phenotypically, should the need arise. With the advent of the antibiotic age, as more and more drugs were developed to treat serious infections, micro-organisms (particularly bacteria) rapidly developed resistance determinants to prevent their own demise.The most important determinants of resistance have been in the Gram-positive and Gram-negative bacteria. Among Gram-positive bacteria, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and penicillin-resistant Streptococcus pneumoniae (PRSP) have taxed researchers and pharmaceutical companies to develop new agents that are effective against these resistant strains. Among the Gram-negative bacteria, extended-spectrum beta-lactamase (ESBL) enzymes, carbapenemases (CREs) and the so-called amp-C enzymes that may be readily transferred between species of enterobacteriaceae and other facultative species have created multi-drug resistant organisms that are difficult to treat. Other resistance determinants have been seen in other clinically important bacterial species such as Neisseria gonorrhoeae, Clostridium difficile, Haemophilus influenzae and Mycobacterium tuberculosis. These issues have now spread to fungal agents of infection.A variety of modalities have been used to stem the tide of resistance. These include the development of niche compounds that target specific resistance determinants. Other approaches have been to find new targets for antimicrobial activity, use of combination agents that are effective against more than one target in the cell, or new delivery mechanism to maximize the concentration of antimicrobial agents at the site of infection without causing toxicity to the host. It is important that such new modalities have been proved effective for clinical therapy. Animal models and non-mammalian systems have been developed to determine if new agents will reach sufficient concentrations at infection sites to predict clinical efficacy without toxicity. It will also be key to consider antimicrobial stewardship as an important component of the continuing battle to prevent the development of antimicrobial resistance.

Caspofungin Etest endpoint for Aspergillus isolates shows poor agreement with the reference minimum effective concentration.

The Clinical and Laboratory Standards Institute (CLSI) M38-A2 reference broth microdilution (BMD) method for the antifungal susceptibility testing of filamentous fungi now includes guidelines for testing echinocandin activity using the minimum effective concentration (MEC) as the endpoint measurement. In this study, we compared the caspofungin Etest MIC on RPMI agar and Mueller-Hinton agar (supplemented with glucose and methylene blue [MGM]) to the BMD MEC for 345 clinical Aspergillus isolates, including A. flavus, A. fumigatus, A. nidulans, A. niger, and A. terreus. The essential agreement (+/-1 log(2) dilution) of the Etest on MGM and RPMI agar with the reference BMD MEC was 18 and 26%, respectively. The geometric mean values for BMD MEC and MGM Etest were 0.137 and 0.024 microg/ml, respectively, and the geometric mean values for BMD and RPMI agar were 0.128 and 0.031 microg/ml, respectively. Comparatively, 91% of paired MGM and RPMI Etest results were within 2 log(2) dilutions of each other and consistently produced clearly defined endpoints. In conclusion, the caspofungin Etest MIC, like the BMD MEC, is a reproducible endpoint but is markedly lower than the reference BMD. In anticipation of susceptibility breakpoint assignments, optimization studies will be required to improve the concordance of these two assays so that the potential for underreporting echinocandin resistance in Aspergillus is mitigated.

Multicenter evaluation of the new Vitek 2 Neisseria-Haemophilus identification card.

The new Neisseria-Haemophilus identification (NH) card for Vitek 2 was compared with 16S rRNA gene sequencing (16S) as the reference method for accurate identification of Neisseria spp., Haemophilus spp., and other fastidious gram-negative bacteria. Testing was performed on the Vitek 2 XL system with modified software at three clinical trial laboratories. Reproducibility was determined with nine ATCC quality control strains tested 20 times over a minimum of 10 days at all three sites. A challenge set of 30 strains with known identifications and 371 recent fresh and frozen clinical isolates were also tested. Expected positive and negative biochemical reactions were also evaluated for substrate reproducibility. All microorganisms were tested on the NH card, and all clinical and stock isolates were saved for 16S testing. All reproducibility tests yielded expected results within a 95% confidence interval. For challenge microorganisms, there was 98% overall correct identification, including 8% low discrimination, 2% incorrect identification, and 0% unidentified. For clinical strains, there was 96.5% overall correct identification, including 10.2% low discrimination, 2.7% incorrect identification, and 0.8% unidentified. The 2.7% (10/371) of clinical isolates that gave an incorrect identification consisted of 7 isolates correct to genus and 3 strains incorrect to genus. There were an additional 27 strains (primarily Neisseria species) for which the 16S identification result was different from the NH card result. These were all unclaimed species by the system. The new NH card met all performance criteria within a 95% confidence interval compared to identification of clinical isolates by 16S.

Multicenter evaluation of the Vitek 2 anaerobe and Corynebacterium identification card.

The new anaerobe and Corynebacterium (ANC) identification card for Vitek 2 was compared with a 16S rRNA gene sequencing (16S) reference method for accuracy in the identification of corynebacteria and anaerobic species. Testing was performed on a Vitek 2 XL system with modified software at three clinical trial laboratories. Reproducibility was determined with nine ATCC quality control strains that were tested 20 times over a minimum of 10 days at all three sites. A challenge set of 50 well-characterized strains and 365 recent fresh and frozen clinical isolates were included in the study. The expected positive and negative biochemical well reactions were also evaluated for substrate reproducibility. All strains were tested with the ANC card, and clinical isolates were saved for 16S rRNA gene sequencing. All reproducibility tests yielded expected results within a 95% confidence interval, except for that with Corynebacterium striatum ATCC 6940, for which identification failed at one trial site. For the challenge isolates, there was 98% correct identification, 5% low discrimination, and 2% incorrect identification, and 0% were unidentified. For clinical strains, there was 95.1% correct identification, 4.9% low discrimination, and 4.6% incorrect identification, and 0.3% were unidentified. The 4.6% (17/365) of clinical isolates that were incorrectly identified consisted of 14 isolates that were correct at the genus level and three that were incorrect at the genus level. The new ANC card met all performance criteria within a 95% confidence interval compared to the identification performance by 16S rRNA gene sequencing.

Determination of moxifloxacin anaerobic susceptibility breakpoints according to the Clinical and Laboratory Standards Institute guidelines.

A summary of the key data presented to Clinical and Laboratory Standards Institute (CLSI, formerly National Committee for Clinical and Laboratory Standards) in determination of moxifloxacin anaerobic breakpoints is presented. The breakpoint analysis required review of a variety of data, including bacteriologic and clinical outcomes by MIC of anaerobic isolates from prospective clinical trials in patients with complicated intra-abdominal infections, human and animal pharmacokinetic/pharmacodynamic (PK/PD) information and in vitro models, MIC distributions of indicated organisms, and animal model efficacy data for strains with MIC values around prospective breakpoints. The compilation of the various components of this breakpoint analysis supports the US Food and Drug Administration (FDA) and CLSI moxifloxacin anaerobic breakpoints of < or =2 mg/L (susceptible), 4 mg/L (intermediate), and > or =8 mg/L (resistant), and provides information to European investigators for interpretation of MICs prior to establishment of the European Committee on Antimicrobial Susceptibility Testing breakpoints.

Antifungal activity of medicinal plant extracts; preliminary screening studies.

ETHNOPHARMACOLOGICAL RELEVANCE: In the setting of HIV and organ transplantation, opportunistic fungal infections have become a common cause of morbidity and mortality. Thus antifungal therapy is playing a greater role in health care. Traditional plants are a valuable source of novel antifungals. AIM OF THE STUDY: To assess in vitro antifungal activity of aqueous plant extracts. The minimum inhibitory concentrations were determined for each extract in the setting of human pathogenic fungal isolates. MATERIALS AND METHODS: Plants were harvested and identification verified. Aqueous extracts were obtained and antifungal susceptibilities determined using serial dilutional extracts with a standardized microdilution broth methodology. Twenty-three fungal isolates were cultured and exposed to the plant extracts. Five known antifungals were used as positive controls. Results were read at 48 and 72 h. RESULTS: Of the 14 plants analyzed, Fragaria virginiana Duchesne, Epilobium angustifolium L. and Potentilla simplex Michx. demonstrated strong antifungal potential overall. Fragaria virginiana had some degree of activity against all of the fungal pathogens. Alnus viridis DC., Betula alleghaniensis Britt. and Solidago gigantea Ait. also demonstrated a significant degree of activity against many of the yeast isolates. CONCLUSION: Fragaria virginiana, Epilobium angustifolium and Potentilla simplex demonstrate promising antifungal potential.

Ralstonia pickettii bacteremia associated with pediatric extracorporeal membrane oxygenation therapy in a Canadian hospital.

We describe 2 pediatric patients with Ralstonia pickettii bacteremia associated with extracorporeal membrane oxygenation (ECMO) therapy. Investigation revealed a common environmental source--the ECMO temperature-control units. We created guidelines for disinfecting these units that do not void the manufacturer's warranty and have prevented additional cases of bacteremia due to this organism.

Methicillin-resistant Staphylococcus aureus with reduced susceptibility to vancomycin in Canada.

This study defines the characteristics of decreasing vancomycin susceptibility in multiple isolates of methicillin-resistant Staphylococcus aureus (MRSA) recovered from a hospitalized patient in Canada over a period of 6 months. The MICs of the isolates increased during therapy with vancomycin. The patient fractured her right hip while in the United States. She was started on treatment with vancomycin. The MICs of successive isolates increased from < or =1 to 4 mg/L over 6 months. Then, an isolate tested at 8 mg/L initially and 4 mg/L with confirmatory E-test (AB BIODISK, Solna, Sweden). One month later, MRSA was still present in her wound, and therapy was changed to linezolid with rifampin. Subsequent cultures were negative for MRSA. Susceptibility testing was performed on the BD Phoenix (Becton Dickinson Diagnostic Systems, Sparks, MD), Dade Microscan (Dade Behring Microscan, Sacramento, CA), Pasco MIC (Becton Dickinson, Sparks, MD), Vitek 2 (bioMerieux, St. Louis, MO), and Sensititre (Trek Diagnostic Systems, Cleveland, OH) systems, and by E-test. Molecular typing (pulsed-field gel electrophoresis [PFGE]) was used to verify the relatedness of the isolates. Transmission electron microscopy (TEM) was used to assess the cell wall thickness of isolates with differing MICs. Population analysis was performed to assess for vancomycin hetero-resistance. MICs of 4 mg/L were only obtained with BD Phoenix, E-test, and broth microdilution. All isolates were identical by PFGE. The most resistant isolate had a thicker cell wall on TEM. Vancomycin hetero-resistance was observed in the resistant isolates. This is the first strain of MRSA with reduced susceptibility to vancomycin reported in Canada. The breakpoints for vancomycin susceptibility have been revised in light of such observations.

Methicillin-resistant Staphylococcus aureus in a Canadian intensive care unit: Delays in initiating effective therapy due to the low prevalence of infection.

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) infection in intensive care units (ICUs) has increased dramatically in prevalence in recent years, and is associated with increased morbidity, mortality and cost of care. The aim of the present study was to describe the epidemiology and outcomes of MRSA infection in the general systems ICU at the University of Alberta Hospital in Edmonton, Alberta. METHODS: A retrospective cohort analysis of patients infected with MRSA in a general systems ICU was conducted from January 1, 1997, to August 15, 2005. RESULTS: Forty-six cases of MRSA were identified, of which 36 (78.3%) were infected. The most common admitting diagnoses included respiratory failure (41.7%) and sepsis or septic shock (36.1%). Infection was hospital acquired in 58.3% of cases (10 cases ICU acquired), with a median time to infection of 11 days. The most common sites of infection were the respiratory tract, skin and blood. Median lengths of stay were 13 days in the unit and 27 days in-hospital. Crude mortality was 55.6%. Time to appropriate antimicrobial treatment was delayed in 80.5% of patients. Four prototypical Canadian MRSA (CMRSA) strains were identified by pulsed-field gel electrophoresis. Hospital-acquired strains were predominantly CMRSA-2 (59%), indicating that this clone circulates at the University of Alberta Hospital. CONCLUSIONS: MRSA infection remains uncommon at the University of Alberta Hospital, resulting in delays in instituting appropriate antimicrobial therapy. To date, only a few community-acquired strains have been noted. ICU acquisition of MRSA remains rare, with only 10 cases over the past nine years. The majority of hospital-acquired strains were CMRSA-2.

Bacterial contamination of health care workers' pagers and the efficacy of various disinfecting agents.

Health care workers in our facility were surveyed, and their pagers were cultured before and after disinfection with various agents. All pagers were contaminated with bacteria, including the pathogens Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella spp. and methicillin-resistant S. aureus. Disinfection reduced bacterial contamination. No risk factors for pager contamination with pathogens were identified.

Variability of ß-lactam susceptibility testing for Streptococcus pneumoniae using 4 commercial test methods and broth microdilution.

Limited data are available that verify the performance of commercial susceptibility methods for Streptococcus pneumoniae following the 2008 Clinical and Laboratory Standards Institute revision of the ß-lactam breakpoints. We compared the performance of Etest, M.I.C. Evaluator (M.I.C.E), Vitek, and Sensititre systems to broth microdilution for S. pneumoniae susceptibility testing of penicillin, ceftriaxone, meropenem, and amoxicillin. Essential agreement was ≥90% for the majority of the ß-lactams and methods tested, particularly for penicillin and ceftriaxone. Categorical agreements (CAs) for penicillin using meningeal and nonmeningeal breakpoints were ≥90%; CAs using penicillin oral breakpoints were 84-89%. Ceftriaxone CAs using nonmeningeal and meningeal breakpoints were 68-88% for Etest, M.I.C.E., and Vitek2 with 6-12% very major errors (VMEs) using meningeal breakpoints. Sensititre CAs for ceftriaxone, amoxicillin, and meropenem were ≥90% with no VMEs. In the context of the current guidelines, there exists considerable method-dependent variability in the susceptibility of S. pneumoniae to ß-lactams.