Invasive Pneumococcal Disease Among Immunocompromised Persons: Implications for Vaccination Programs.

BACKGROUND: In 2012/2013, a single dose of 13-valent pneumococcal conjugate vaccine (PCV13) was recommended for immunocompromised adults in the United States and Canada. To assess the potential benefits of this recommendation, we assessed the serotype-specific burden of invasive pneumococcal disease (IPD) among immunocompromised individuals. METHODS: From 1995 to 2012, population-based surveillance for IPD was conducted in Metropolitan Toronto and Peel Region, Canada. Disease incidence and case fatality were measured in immunocompromised populations over time, and the contribution of different serotypes determined. RESULTS: Overall, 2115/7604 (28%) episodes of IPD occurred in immunocompromised persons. IPD incidence was 12-fold higher (95% confidence interval [CI], 8.7-15) in immunocompromised compared to immunocompetent persons; the case fatality rate was elevated in both younger (odds ratio [OR] 1.8) and older (OR 1.3) adults. Use of immunosuppressive medications was associated with a 2.1-2.7 fold increase in the risk of IPD. Five years after PPV23 program implementation, IPD incidence had declined significantly in immunocompromised adults (IRR 0.57, 95% CI, .40-.82). Ten years after pediatric PCV7 authorization, IPD due to PCV7 serotypes had decreased by 90% (95% CI, 77%-96%) in immunocompromised persons of all ages. In 2011/2012, 37% of isolates causing IPD in immunocompromised persons were PCV13 serotypes and 27% were PPV23/not PCV13 serotypes. CONCLUSIONS: Immunocompromised individuals comprised 28% of IPD. Both PPV23 and herd immunity from pediatric PCV7 were associated with reductions in IPD in immunocompromised populations. PCV13 vaccination of immunocompromised adults may substantially reduce the residual burden until herd immunity from pediatric PCV13 is fully established.

Bacteremia due to Pasteurella dagmatis acquired from a dog bite, with a review of systemic infections and challenges in laboratory identification.

A case of bacteremia in a 74-year-old man, which was caused by Pasteurella dagmatis and complicated by thrombocytopenia, is presented. Microorganism identification was performed by the provincial reference laboratory using traditional biochemical profiling, completmented with both the sequencing of the 16S ribosomal RNA gene and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; antibiotic-susceptibility testing was also performed. After treatment with the appropriate antibiotics, the patient fully recovered. Systemic infections attributed to this organism are rarely reported in the literature. Other reported cases of bacteremia due to P dagmatis are reviewed and compared with the present case. The challenges of relying on standard automatic identification are discussed, with alternative methodologies provided.

Les auteurs présentent un cas de bactériémie chez un homme de 74 ans, causé par un Pasteurella dagmatis et compliqué par une thrombocytopénie. Le laboratoire de référence provincial a identifié le microorganisme au moyen du profilage biochimique classique et l'a complété par le séquençage du gène de l'ARN ribosomique 16S et par la spectrométrie de masse à temps de vol par désorption-ionisation laser assistée par matrice. Le laboratoire a également effectué un test de susceptibilité aux antibiotiques. Après un traitement antibiotique pertinent, le patient s'est complètement rétabli. Les publications scientifiques contiennent peu de déclarations d'infections systémiques attribuées à cet organisme. D'autres cas de bactériémie à P dagmatis sont analysés et comparés à la présente situation. Les problèmes liés à l'identification automatique standard sont exposés et d'autres méthodologies sont proposées.

Characterization of methicillin-resistant Staphylococcus aureus isolates from patients with persistent or recurrent bacteremia.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSI) are associated with considerable morbidity and mortality, especially with persistent (PB) or recurrent bacteremia (RB). OBJECTIVE: To determine the frequency of PB and RB in patients with MRSA BSI, and to characterize the isolates from these patients. METHODS: Surveillance for MRSA BSI was performed for one year in 13 Canadian hospitals. PB was defined as a positive blood culture that persisted for ≥7 days; RB was defined as the recurrence of a positive blood culture ≥14 days following a negative culture. Isolates were typed using pulsed-field gel electrophoresis (PFGE). Vancomycin susceptibility was determined using Etest. RESULTS: A total of 183 patients with MRSA BSI were identified; 14 (7.7%) had PB and five (2.7%) had RB. Ten (5.5%) patients were known to have infective endocarditis, and five of these patients had PB or RB. Initial and subsequent MRSA isolates from patients with PB and RB had the same PFGE type. There were no significant differences in the distribution of PFGE types in patients with PB or RB (37% CMRSA-2/USA100; 37% CMRSA-10/USA300) compared with that in other patients (56% CMRSA-2/USA100; 32% CMRSA-10/USA300). All isolates were susceptible to vancomycin, but patients with PB or RB were more likely to have initial isolates with vancomycin minimum inhibitory concentration = 2.0 µg/mL (26% versus 10%; P=0.06). CONCLUSIONS: Persistent or recurrent MRSA bacteremia occurred in 10.4% of patients with MRSA BSIs. Initial isolates from patients with persistent or recurrent MRSA BSIs were more likely to exhibit reduced susceptibility to vancomcyin, but were not associated with any genotype.

HISTORIQUE: Les infections sanguines (IS) par le Staphylococcus aureus résistant à la méthicilline (SARM) s'associent à une morbidité et une mortalité considérables, particulièrement en présence d'une bactériémie persistante (BP) ou récurrente (BR). OBJECTIF: Déterminer la fréquence de BP et de BR chez les patients atteints d'une IS par le SARM et en caractériser les isolats. MÉTHODOLOGIE: Les chercheurs ont surveillé les IS par le SARM dans 13 hôpitaux canadiens pendant un an. La BP se définissait par une hémoculture positive qui persistait au moins sept jours, tandis que la BR désignait la récurrence d'une hémoculture positive au moins 14 jours après une hémoculture négative. Les chercheurs ont typé les isolats au moyen de l'électrophorèse sur gel en champ pulsé (ECP). Ils ont déterminé la susceptibilité à la vancomycine par Etest. RÉSULTATS: Les chercheurs ont retracé un total de 183 patients ayant une IS par le SARM. De ce nombre, 14 (7,7 %) avaient une BP et cinq (2,7 %), une BR. Dix patients (5,5 %) étaient atteints d'une endocardite infectieuse diagnostiquée, dont cinq avaient une BP ou une BR. Les isolats initiaux et subséquents de SARM chez les patients ayant une BP ou une BR présentaient le même type d'ECP. Il n'y avait pas de différence significative dans la distribution des types d'ECP chez les patients ayant une BP ou une BR (37 % de souche CSARM-2/USA100; 37% de souche CSARM-10/USA300) par rapport à celle des autres patients (56 % de souche CSARM-2/USA100; 32 % de souche CSARM-10/USA300). Tous les isolats étaient susceptibles à la vancomycine, mais les patients atteints d'une BP ou d'une BR étaient plus susceptibles de présenter des isolats initiaux de vancomycine dont la CMI = 2,0 µg/mL (26 % par rapport à 10 %; P=0,06). CONCLUSIONS: Les chercheurs ont observé une BP ou une BR par le SARM chez 10,4 % des patients atteints d'une IS par le SARM. Les isolats initiaux des patients atteints d'une IS persistante ou récurrente par le SARM risquaient davantage d'être moins susceptibles à la vancomycine, mais ne s'associaient à aucun génotype.

Cutaneous mucormycosis in the immunocompromised host: An important cause of persistent post traumatic skin lesions.

We describe a case of a 31-year-old man with a history of ocular non-Hodgkin's lymphoma who presented with a large 12-cm non-resolving traumatic skin lesion on his back. Biopsy showed fungal elements, and on fungal culture, Rhizopus arrhizus (formerly R. oryzae) was isolated. Cutaneous mucormycosis is an important diagnostic consideration for a non-resolving skin lesion in an immunocompromised host. Early tissue sampling is key, and diagnostic certainty is particularly important because first line therapy, liposomal amphotericin B, has significant systemic toxicities, notable renal toxicity, and is therefore challenging to continue empirically. Surgical debridement is an integral part of therapy, highlighting the need for early multidisciplinary care in patients with cutaneous mucormycosis.

Early diagnosis of monomicrobial Clostridioides difficile bacteremia in a patient without colitis.

Bacteremia is a rare finding among Clostridioides difficile infections. We describe a case of a 67-year-old man with resected colorectal cancer with colostomy who presented with small bowel obstruction and was admitted for lysis of adhesions. On day 8 of admission, he developed leukocytosis and raised inflammatory markers with isolation of Gram-positive bacilli in several blood cultures, which was presumptively identified through blood culture pelleting and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) as C. difficile. The diagnosis was confirmed with conventional culture and reference lab identification and the patient demonstrated clinical response with parenteral then oral vancomycin that briefly worsened when therapy was switched to parenteral metronidazole and then improved once oral vancomycin was resumed. Our case was notable in that the combination of pelleting and MALDI-TOF offered early diagnosis in this patient whose positive blood cultures were suspicious for contamination and in whom there was an absence of diarrheal illness or features of colitis on abdominal imaging. Early diagnosis is critical for the timely initiation of therapy, implementation of infection prevention and control measures and in selection of appropriate therapy for antimicrobial stewardship.

La bactériémie est rare lors d'une infection à Clostridioides difficile. Les auteurs décrivent le cas d'un homme de 67 ans ayant une colostomie découlant de la résection d'un cancer colorectal, qui a consulté à cause d'une occlusion du grêle et a été hospitalisé pour traiter des adhésiolyses. Le huitième jour de l'hospitalisation, il a présenté une leucocytose et une augmentation des marqueurs inflammatoires, des bacilles à Gram positif ont été isolés dans plusieurs hémocultures, et un diagnostic provisoire de C. difficile a été posé par culot de sang et désorption/ionisation laser assistée par matrice par temps de vol (MALDI-TOF). Le diagnostic a été confirmé par une culture classique et par le laboratoire de référence, et le patient a affiché une réponse clinique à la vancomycine par voie parentérale, puis par voie orale. Son état s'est brièvement aggravé lors du passage au métronidazole par voie parentérale, puis s'est amélioré à la reprise de la vancomycine par voie orale. Le cas était remarquable parce que la combinaison du culot et de la MALDI-TOF a permis d'obtenir un diagnostic rapide chez ce patient dont les hémocultures positives ont suggéré une contamination dont l'imagerie abdominale ne révélait pas de maladie diarrhéique ni de caractéristiques de colite. Il est essentiel de poser un diagnostic précoce pour entreprendre le traitement rapidement, adopter des mesures de prévention et de contrôle des infections et sélectionner le traitement approprié à la gouvernance antimicrobienne.

A review of amoebic liver abscess for clinicians in a nonendemic setting.

Amoebic liver abscess (ALA) is an uncommon but potentially life-threatening complication of infection with the protozoan parasite Entamoeba histolytica. E histolytica is widely distributed throughout the tropics and subtropics, causing up to 40 million infections annually. The parasite is transmitted via the fecal-oral route, and once it establishes itself in the colon, it has the propensity to invade the mucosa, leading to ulceration and colitis, and to disseminate to distant extraintestinal sites, the most common of which is the liver. The authors provide a topical review of ALA and summarize clinical data from a series of 29 patients with ALA presenting to seven hospitals in Toronto, Ontario, a nonendemic setting, over 30 years.

Monkey finger mycology? First case of otomycosis externa caused by Trichophyton simii after encounter with a monkey.

Unilateral ear pain, ear canal blockage and reduced hearing in an 18-year-old Canadian male who had travelled to India revealed, on examination of a swab, secretions bearing unusual fungal filaments visually suggestive of dermatophyte elements. Culture yielded Trichophyton simii, an unusual skin infecting species with a worldwide distribution but most often seen from India. The patient recalled swimming in the Ganges River but also had had his ear manipulated by a street monkey.

The type isolate of a rare Phaeoacremonium species as a cause of human eumycetoma.

An isolate of unknown identity that had been identified as causing eumycetoma was retained in an international culture collection, and eventually became the nomenclatural type isolate of the rarely encountered Phaeoacremonium sphinctrophorum. The case featured an indurated, painless, swollen lesion on the dorsum of the foot that had developed in a Canadian resident who had previously been a farmer in Laos. Resection alone was curative.

Case Report: Central Nervous System Strongyloidiasis: Two Cases Diagnosed Antemortem.

Central nervous system (CNS) strongyloidiasis is a known but rare form of disseminated infection. The diagnosis is often made postmortem, with only five published cases of an antemortem diagnosis. We report two fatal cases of CNS strongyloidiasis diagnosed antemortem, with Strongyloides stercoralis larvae visualized in the CNS sample in one case. Risk factors for disseminated strongyloidiasis common to both cases included origination from the Caribbean, underlying human T-lymphotropic virus-1 infection, and recent prednisone use. Both cases occurred in Canada, where the occurrence of Strongyloides is uncommon, and serve as a reminder to maintain a high index of suspicion in patients with epidemiologic or clinical risk factors for dissemination.

Case Report: Two Cases of Strongyloidiasis Presenting with Thrombotic Events.

We report two unusual cases of clinical strongyloidiasis that present as extensive thrombosis: a case of hyperinfection with concurrent eosinophilia and a case of disseminated infection as a complication of immunosuppression. We discuss risk factors for the development of Strongyloides stercoralis infection and thromboembolism, and the recommended management.

Surveillance for hospital outbreaks of invasive group a streptococcal infections in Ontario, Canada, 1992 to 2000.

BACKGROUND: Streptococcus pyogenes can cause severe disease in the individual patient and dramatic hospital outbreaks. OBJECTIVE: To describe the epidemiology of hospital outbreaks of invasive group A streptococcal infection in order to understand the potential benefit of proposed outbreak investigation and management strategies. DESIGN: Prospective, population-based surveillance. SETTING: Short-term care hospitals in Ontario, Canada. PATIENTS: Persons with a positive culture for group A streptococcus from a normally sterile site between 1 January 1992 and 31 December 2000. MEASUREMENTS: Laboratory-based surveillance identified patients with nosocomial invasive group A streptococcal infection. Epidemiologic and microbiological investigations were used to detect transmission. RESULTS: Of 2351 cases of invasive group A streptococcal disease, 291 (12%) were hospital acquired. Twenty-nine (10%) nosocomial cases occurred as part of 20 outbreaks. Seventy percent (14 of 20) of outbreaks involved nonsurgical, nonobstetric patients. Community-acquired cases initiated 25% of outbreaks; most were cases of necrotizing fasciitis in patients admitted to the intensive care unit. Outbreaks were small (median, 2 cases [range, 2 to 10 cases]) and short (median duration, 6 days [range, 0 to 30 days]). The median time between the first 2 cases was 4.5 days. The most common mode of propagation was patient-to-patient transmission. A staff carrier was the primary mode of transmission in 2 (10%) outbreaks, but 1 or more health care workers were colonized with the outbreak strain in 6 of 18 (33%) other outbreaks. LIMITATIONS: Some outbreaks with 1 case of invasive disease may have been missed; advice provided to participating hospitals may have reduced the number and size of outbreaks. CONCLUSIONS: Practices to prevent hospital transmission of group A streptococci should include isolation of patients admitted to the intensive care unit with necrotizing fasciitis, investigation after a single nosocomial case, and emphasis on identifying and treating health care worker carriers on surgical and obstetric services and patient reservoirs on other wards.

Acute Liver Injury Associated with Khat Use in a 24-Year-Old Male.

Chewing khat leaves (Catha edulis) is common cultural practice in Eastern African countries. Khat has been implicated in cases of acute liver injury, sometimes leading to liver failure and requiring transplantation. We report the case of a 24-year-old gentleman presenting with symptoms of acute liver failure. Bloodwork demonstrated hepatocyte-predominant liver injury. Microbiological and serological hepatitis panels were negative, and his liver biopsy demonstrated acute cholestatic hepatitis. He admitted to regular khat use for several years prior to his presentation. His liver function tests improved with cessation of khat use. This is the first reported case of acute khat-associated hepatitis in Canada. Considering cultural practices such as khat chewing in presentations of acute liver injury are important when caring for diverse patient populations.

Complete Genome of a Panresistant Pseudomonas aeruginosa Strain, Isolated from a Patient with Respiratory Failure in a Canadian Community Hospital.

We report here the complete genome sequence of a panresistant Pseudomonas aeruginosa strain, isolated from a patient with respiratory failure in Canada. No carbapenemase genes were identified. Carbapenem resistance is attributable to a frameshift in the oprD gene; the basis for colistin resistance remains undetermined.