Microbiology sampling in non-cystic fibrosis bronchiectasis cases from northern Alberta.

Non-cystic fibrosis bronchiectasis (NCFB) is a chronic respiratory disease resulting in chronic cough, thick sputum, and lower airway microbial colonization, akin to patients with cystic fibrosis (CF). NCFB is a common, yet under recognized entity which inflicts significant morbidity and mortality particularly to older individuals, with a rising prevalence in the developed world. Given that sputum cultures are a non-invasive method to characterize the lower airway microbiota in NCFB patients, for which pathogenic organisms are associated with worsened outcomes, we sought to characterize the microbiological pattern and clinical outcomes associated with sputum culture in a cohort of NCFB patients from Western Canada. A total of 20 subjects were prospectively recruited from various bronchiectasis clinics across the Greater Edmonton area. A retrospective chart review and a symptoms questionnaire was performed, gathering information not limited to symptoms, comorbidities, exacerbations, hospitalizations, sputum production, and sputum culture results over the prior 5 years. Subjects reported frequent hospitalization alongside a significant burden of symptoms. A large majority of sputum cultures grew pathogenic organisms such as Haemophilus influenzae and Pseudomonas aeruginosa. We also note the considerable waste and inefficiency associated with sputum cultures, outlining areas for which this important diagnostic modality can be improved. Accurate characterization of the airway microbiota alongside efficient delivery of health services are key to ensuring the proper treatment of individuals with NCFB, given their high disease burden and frequent hospitalization.

Mycobacterium chimaera Encephalitis Following Cardiac Surgery: A New Syndrome.

We report the cases of 3 patients with fatal, disseminated Mycobacterium chimaera infections following cardiac surgeries. Progressive neurocognitive decline and death were explained by active granulomatous encephalitis, with widespread involvement of other organs. This syndrome is clinically elusive and, thus, may have caused deaths in prior reported series.

Cutaneous Nontuberculous Mycobacterial Infections in Alberta, Canada: An Epidemiologic Study and Review.

BACKGROUND: Cutaneous infections caused by nontuberculous mycobacteria (NTM) occur infrequently. Nonetheless, the incidence of NTM infections is reported to be increasing. In Canada, cutaneous NTM infections have not been well described. OBJECTIVES: A database review from 2006 to 2016 was done to assess species frequency, incidence, and trends of the most common cutaneous NTMs in the province of Alberta, Canada. We also reviewed major diagnostic and epidemiologic aspects of NTM cutaneous infections with a focus on Mycobacterium marinum. RESULTS: A database search identified 244 cases of NTM infections. Mycobacterium avium-intracellulare complex had the highest incidence, causing 64% of cases. Rapid growers ( Mycobacterium abscessus, Mycobacterium chelonae, Mycobacterium fortuitum) caused 23% and M marinum 13%. Information on infection site was available for 117 cases. There was no difference noted in sex distribution; however, differences in age groups between species were noted. CONCLUSIONS: The incidence of NTM cutaneous infections in Alberta, Canada, was reported for the first time and the incidence of M marinum was found to be similar to that reported in the worldwide literature. Patients' age groups were different between species. Knowledge of the unique microbiological features of NTMs and the role of the diagnostic laboratory are important.

Mycobacterium branderi infection: Case report and literature review of an unusual and difficult-to-treat non-tuberculous mycobacterium.

A 67-year-old man with significant smoking history presented with fever, unintentional weight loss, night sweats, productive cough, and progressive dyspnea. Multiple respiratory specimens grew Mycobacterium branderi. Computed tomography scanning of the chest revealed a cavitary right upper lung lesion. Bronchoscopy and thoracoscopic biopsy were negative for malignancy but showed necrotizing granulomatous inflammation, which was culture negative. Due to clinical and radiologic progression despite therapy with clarithromycin, ethambutol and moxifloxacin, the lesion was surgically resected and the patient's symptoms resolved. Mycobacteria were seen in histopathology but did not grow from resected tissue. The patient received an additional 6 months of medical therapy and remains asymptomatic 1 month after completing antimicrobials. Cases of M. branderi causing human infection are very rarely reported. This is a novel case of multi-drug resistant M. branderi pulmonary infection in an apparently immunocompetent patient, progressive despite medical therapy and requiring surgical resection for definitive management.

Current Smoking and Reduced Mortality in Bacteremic Pneumococcal Pneumonia: A Population-Based Cohort Study.

BACKGROUND: Previous studies suggest that smoking is independently associated with decreased mortality in patients with pneumonia. We hypothesized that this is a result of acquiring differential pneumococcal serotypes (ie, smokers with pneumococcal pneumonia are more likely to experience bacteremia, with low case fatality rate (CFR) serotypes). We tested this hypothesis in a population-based cohort of patients with bacteremic pneumococcal pneumonia (BPP). METHODS: Our prospective population-based clinical registry included 1,636 adults (≥ 18 years) with BPP who were hospitalized between 2000 and 2010 in northern Alberta, Canada. Using multivariable logistic regression, we determined the adjusted risk of all-cause in-hospital mortality according to smoking status (current vs not current) and conducted stratified analyses by serotypes (low CFR vs all other CFRs) according to smoking status. RESULTS: The average patient age was 54 years, 57% were men, 49% were current smokers, and 41% had low-CFR serotypes. Overall, 62 of 809 current smokers died in the hospital vs 164 of 827 nonsmokers (8% vs 20%; adjusted OR, 0.52; 95% CI, 0.36-0.77; P = .001). Current smokers were more likely to have low-CFR-serotype isolates than were nonsmokers (53% vs 29%; adjusted OR, 1.67; 95% CI, 1.31-2.12; P < .001) and in models adjusted for low-CFR serotype, smoking remained independently associated with reduced mortality (P = .001). CONCLUSIONS: Compared with nonsmokers, current smokers with BPP had a decreased risk of in-hospital mortality and were more likely to experience bacteremia with low CFR serotypes. These findings, at least in part, may explain why previous studies showed that smoking was associated with lower mortality in patients with pneumonia.

Identification of genes affecting expression of phosphoglycerate kinase on the surface of group B streptococcus.

Group B streptococcal phosphoglycerate kinase (GBS-PGK), a glycolytic enzyme, has previously been identified on the surface of group B streptococcus (GBS). To identify genes involved in surface expression of GBS-PGK, we performed Tn917 mutagenesis followed by quantification of PGK expressed on the GBS surface. Tn917 mutagenesis identified 4 genes (sag0966, sag0979, sag0980, and sag1003) that when disrupted, alter expression of GBS-PGK on the bacterial surface. Three of the identified genes were localized to a region of the GBS genome containing genes (sag0973-sag0977) predicted to be involved in resistance to antimicrobial peptides. One mutant isolate, designated NCS13sag1003::Tn917, was found to have increased sensitivity to the antimicrobial peptides bacitracin and nisin. In addition, all of the mutant strains assayed were found to have decreased ß-hemolysis. In conclusion, we have identified genes involved in surface expression of GBS-PGK. These genes also appear to be involved in antimicrobial peptide resistance and regulate expression of the ß-hemolysin.

Mycobacterium marinum infection from sea monkeys.

A case of cutaneous Mycobacterium marinum infection acquired from Artemia nyos (sea monkeys) is presented. The infection was unresponsive to initial antimicrobial therapies. A biopsy of a lesion revealed granulomatous inflammation with cultures that subsequently grew M marinum. A three-month course of clarithromycin provided complete resolution.

Les auteurs présentent un cas d'infection cutanée à Mycobacterium marinum transmise par des Artemia nyos (crevettes des salines). L'infection n'a pas répondu au traitement antimicrobien initial. Une biopsie de la lésion a révélé une inflammation granulomateuse, et les cultures ont ensuite été positives à M marinum. Grâce à un traitement de trois mois à la clarithromycine, l'infection a complètement disparu.

Factors predicting mortality in invasive pneumococcal disease in adults in Alberta.

To define the factors associated with 30-day mortality among adult patients with invasive pneumococcal disease (IPD), we conducted a retrospective review of all cases of IPD in Alberta from 2000 to 2004. We hypothesized that multiple factors would be predictive of such mortality. We also examined the factors predictive of early (within 5 days of admission) mortality. We identified 1154 patients who met our inclusion criteria, 163 (14.1%) of whom died within 30 days. Over half (62.6%) of the deaths occurred within 5 days of admission. Ten factors were independently associated with increased 30-day mortality: 3 comorbidity factors-cancer within 5 years of diagnosis of IPD, diabetes, and cirrhosis; 4 complications-requirement for supplemental oxygen, mechanical ventilation, alteration of mental status, and cardiac arrest; 2 microorganism-related factors-infection with high- or infection with intermediate-mortality serotypes; and 1 treatment-related factor-treatment with a single antibiotic. Age 18-40 years and treatment with 2 antibiotics concurrently were associated with lower 30-day mortality. Comorbid illnesses were not contributory to early mortality (within 5 days of admission); instead, complications (alteration of mental status, requirement for supplemental oxygen, mechanical ventilation, and cardiac arrest) as well as infection with high-mortality serotypes and treatment with a single antibiotic were important. Age 18-40 years, infection with serotypes in the polysaccharide vaccine, and treatment with 2 or more than 2 antibiotics were associated with decreased early mortality. Early mortality accounted for 62.6% of the deaths. In conclusion, we found that mortality in IPD is multifactorial, the factors differ for 5- and 30-day mortality, and mortality is associated with host (age and complications), microorganism (pneumococcal serotypes), and therapeutic factors. Our data indicate that treatment with 2 or more antibiotics effective against Streptococcus pneumoniae should be used to treat IPD.

Welders are at increased risk for invasive pneumococcal disease.

BACKGROUND: Welders are at increased risk of pulmonary infection and lobar pneumonia, likely due to significant occupational exposure to metal fumes. We hypothesized that welders would be at increased risk for invasive pneumococcal disease (IPD) compared to the general population. METHODS: A retrospective chart review of all patients with IPD in the province of Alberta, Canada (population approx. 3.3 million) was conducted from 2000 to 2004 to study the epidemiology of IPD. RESULTS: There were 18 cases identified in welders, giving an attack rate of 22.7 cases per 100,000 population per year (95% confidence interval (CI) 12.23-33.23). Compared with an attack rate of 8.7 cases per 100,000 population per year (95% CI 8.10-9.26) for the general adult population between ages 18 and 65 years, there was a 2.7-fold greater incidence of IPD in welders (95% CI 1.67-4.22, p<0.001). There was an increased prevalence of serotypes 4 and 8 compared to the general population. Eight of 18 cases were caused by serotypes in the 7-valent pneumococcal conjugate vaccine, 11 of 18 cases by serotypes in the 13-valent pneumococcal conjugate vaccine, and 18 of 18 cases by serotypes in the 23-valent pneumococcal polysaccharide vaccine. Seventeen patients had bacteremic pneumococcal pneumonia and one had meningitis; one person died due to infection. Fifteen of 18 patients were either current or former smokers, which was a higher rate than the general population adjusted for age and gender (odds ratio 2.976, 95% CI 0.908-9.729, p=0.084). CONCLUSIONS: Welders, particularly those who smoke, are at increased risk of IPD and should be considered for routine administration of the pneumococcal polysaccharide vaccine. Ongoing workplace measures to reduce exposure to metal fumes and promote smoking cessation should be reinforced.

Population-based surveillance for invasive pneumococcal disease in homeless adults in Toronto.

BACKGROUND: Identification of high-risk populations for serious infection due to S. pneumoniae will permit appropriately targeted prevention programs. METHODS: We conducted prospective, population-based surveillance for invasive pneumococcal disease and laboratory confirmed pneumococcal pneumonia in homeless adults in Toronto, a Canadian city with a total population of 2.5 M, from January 1, 2002 to December 31, 2006. RESULTS: We identified 69 cases of invasive pneumococcal disease and 27 cases of laboratory confirmed pneumococcal pneumonia in an estimated population of 5050 homeless adults. The incidence of invasive pneumococcal disease in homeless adults was 273 infections per 100,000 persons per year, compared to 9 per 100,000 persons per year in the general adult population. Homeless persons with invasive pneumococcal disease were younger than other adults (median age 46 years vs 67 years, P<.001), and more likely than other adults to be smokers (95% vs. 31%, P<.001), to abuse alcohol (62% vs 15%, P<.001), and to use intravenous drugs (42% vs 4%, P<.001). Relative to age matched controls, they were more likely to have underlying lung disease (12/69, 17% vs 17/272, 6%, P = .006), but not more likely to be HIV infected (17/69, 25% vs 58/282, 21%, P = .73). The proportion of patients with recurrent disease was five fold higher for homeless than other adults (7/58, 12% vs. 24/943, 2.5%, P<.001). In homeless adults, 28 (32%) of pneumococcal isolates were of serotypes included in the 7-valent conjugate vaccine, 42 (48%) of serotypes included in the 13-valent conjugate vaccine, and 72 (83%) of serotypes included in the 23-valent polysaccharide vaccine. Although no outbreaks of disease were identified in shelters, there was evidence of clustering of serotypes suggestive of transmission of pathogenic strains within the homeless population. CONCLUSIONS: Homeless persons are at high risk of serious pneumococcal infection. Vaccination, physical structure changes or other program to reduce transmission in shelters, harm reduction programs to reduce rates of smoking, alcohol abuse and infection with bloodborne pathogens, and improved treatment programs for HIV infection may all be effective in reducing the risk.

Commonly invasive serotypes of Streptococcus pneumoniae trigger a reduced innate immune response compared with serotypes rarely responsible for invasive infection.

Although there are more than 90 serotypes of Streptococcus pneumoniae (or pneumococcus), it is not understood why a small number of serotypes account for most invasive infections. To investigate the human innate immune response triggered by different pneumococcal serotypes, monocyte-derived macrophages were exposed to a group of commonly and rarely invasive pneumococcal clinical isolates and tumor necrosis factor (TNF)-alpha production was measured. Commonly invasive pneumococcal serotypes triggered significantly less TNF-alpha production than serotypes rarely responsible for invasive infection (P<0.004). These data indicate that one factor influencing the invasive potential of a pneumococcal serotype is the magnitude of innate immune-mediated TNF-alpha production triggered by exposure to the organism and suggest that the integrated host response generated against commonly invasive pneumococcal serotypes may be less effective than the response directed against rarely invasive serotypes.

Invasion of HeLa cells by group B streptococcus requires the phosphoinositide-3-kinase signalling pathway and modulates phosphorylation of host-cell Akt and glycogen synthase kinase-3.

The group B streptococcus (GBS) is an opportunistic bacterial pathogen with the ability to cause invasive disease. While the ability of GBS to invade a number of host-cell types has been clearly demonstrated, the invasion process is not well understood at the molecular level. What has been well established is that modulation of host-cell actin microfilaments is essential for GBS invasion to occur. Phosphoinositide-3 kinase (PI3K) is a key regulator of the cytoskeleton in eukaryotic cells. Our goal in this investigation was to explore the role of the PI3K/Akt signalling pathway in epithelial cell invasion by GBS. The epithelial cell invasion process was mimicked using the HeLa 229 cell-culture model. Treating HeLa cells with chemical inhibitors of PI3K, Akt or Ras prior to bacterial infection inhibited GBS invasion but not attachment; treatment with 30 microM LY294002 (PI3K inhibitor) reduced GBS invasion by 75%, 20 microM L-6-hydroxymethyl-chiro-inositol 2-(R)-2-O-methyl-3-O-octadecylcarbonate (ICIO) (Akt inhibitor) reduced GBS invasion by 50%, and 10 microM manumycin A (Ras inhibitor) inhibited GBS invasion by 90%. Genetic inactivation of the p85alpha or p110alpha PI3K subunits in HeLa cells also reduced GBS invasion by 55 and 30%, respectively. Western blot analysis revealed that phosphorylation of host-cell Akt and glycogen synthase kinase-3 (GSK-3) occurs in response to GBS infection, and that this is mediated upstream by PI3K. Infection of HeLa cells with GBS triggers pro-survival signalling and protects the HeLa cells from camptothecin-induced caspase-3 cleavage. The results from this investigation show that GBS both requires and activates the PI3K/Akt host-cell signalling pathway during invasion of epithelial cells.

Rac1, RhoA, and Cdc42 participate in HeLa cell invasion by group B streptococcus.

The group B streptococcus (GBS) is an important human pathogen with the ability to cause invasive disease. To do so, the bacteria must invade host cells. It has been well documented that GBS are able to invade a variety of nonphagocytic host cell types, and this process is thought to involve a number of pathogen-host cell interactions. While some of the molecular aspects of the GBS-host cell invasion process have been characterized, many events still remain unclear. The objective of this investigation was to evaluate the role of the Rho-family GTPases Rac, Rho, and Cdc42 in GBS invasion into epithelial cells. The epithelial cell invasion process was modeled using HeLa 229 cell culture. Treatment of HeLa cells with 10 microM compactin, a pan-GTPase inhibitor, abolished GBS internalization, suggesting that GTPases are involved in the GBS invasion process. The addition of Toxin B or exoenzyme C3 to HeLa cells before GBS infection reduced invasion by 50%, further suggesting that the Rho-family GTPases are involved in GBS entry. Examining invasion of GBS into HeLa cells with altered genetic backgrounds was used to confirm these findings; GBS invasion into HeLa cells transiently transfected with dominant negative Rac1, Cdc42, or RhoA reduced invasion by 75%, 51%, and 42%, respectively. Results of this study suggest that the Rho-family GTPases are required for efficient invasion of HeLa cells by GBS.

Bacteremic pneumococcal pneumonia: a prospective study in Edmonton and neighboring municipalities.

Bacteremic pneumococcal pneumonia (BPP) is an important disease that should be frequently re-evaluated due to changes in demographics and recommended treatment. We conducted a prospective study from 2000 to 2002 in adults aged 17 years and over who presented to any of 6 hospitals and 1 freestanding emergency room in Edmonton, Alberta, with signs and symptoms compatible with pneumonia, a chest radiograph interpreted as pneumonia by the attending physician, and a positive blood culture for Streptococcus pneumoniae. We identified 129 patients with BPP, for an overall incidence of 9.7/100,000 person years. The rate was markedly higher among pregnant women, homeless persons, and those in prison. Sixteen percent were managed as outpatients, 61.2% as ward patients, and 22.5% required admission to the intensive care unit (ICU). Tobacco smoking was predictive of BPP, and antibiotic therapy before presentation was protective. According to pneumonia severity index, 47.3% were in low-risk classes I-III, 31.0% were in class IV, and 21.7% were in class V. Twelve (9.3%) patients died. Four died within 24 hours of arrival at hospital, and 2 had end-stage lung disease that resulted in a decision to discontinue therapy. Of the S. pneumoniae isolates, 12.5% were not susceptible to penicillin. The overall rate of BPP appears to be decreasing, although the rate is markedly increased in certain populations, which now should be targeted for vaccination. We identified 3 subsets of patients with BPP according to the site of care (ambulatory, ward, and ICU), with different outcomes.