Truncation in the tcdC region of the Clostridium difficile PathLoc of clinical isolates does not predict increased biological activity of Toxin B or Toxin A

<p>Abstract</p> <p>Background</p> <p>The increased severity of disease associated with the NAP1 strain of <it>Clostridium difficile </it>has been attributed to mutations to the <it>tcdC </it>gene which codes for a negative regulator of toxin production. To assess the role of hyper-production of Toxins A and B in clinical isolates of <it>Clostridium difficile</it>, two NAP1-related and five NAP1 non-related strains were compared.</p> <p>Methods</p> <p>Sequencing was performed on <it>tcdC</it>, <it>tcdR</it>, and <it>tcdE</it> to determine if there were differences that might account for hyper-production of Toxin A and Toxin B in NAP1-related strains. Biological activity of Toxin B was evaluated using the HFF cell CPE assay and Toxin A biological activity was assessed using the Caco-2 Trans-membrane resistance assay.</p> <p>Results</p> <p>Our results confirm that Toxin A and Toxin B production in NAP1-related strains and ATCC 43255 occurs earlier in the exponential growth phase compared to most NAP1-nonrelated clinical isolates. Despite the hyper-production observed in ATCC 43255 it had no mutations in <it>tcdC</it>, <it>tcdR </it>or <it>tcdE</it>. Analysis of the other clinical isolates indicated that the kinetics and ultimate final concentration of Toxin A and B did not correlate with the presence or lack of alterations in <it>tcdC</it>, <it>tcdR </it>or <it>tcdE</it>.</p> <p>Conclusion</p> <p>Our data do not support a direct role for alterations in the <it>tcdC </it>gene as a predictor of hyperproduction of Toxin A and B in NAP1-related strains.</p

Leptospirosis during Dengue Outbreak, Bangladesh

We collected acute-phase serum samples from febrile patients at 2 major hospitals in Dhaka, Bangladesh, during an outbreak of dengue fever in 2001. A total of 18% of dengue-negative patients tested positive for leptospirosis. The case-fatality rate among leptospirosis patients (5%) was higher than among dengue fever patients (1.2%)

Generic First Order Orientation Transition of Vortex Lattices in Type II Superconductors

First order transition of vortex lattices (VL) observed in various superconductors with four-fold symmetry is explained microscopically by quasi-classical Eilenberger theory combined with nonlocal London theory. This transition is intrinsic in the generic successive VL phase transition due to either gap or Fermi velocity anisotropies. This is also suggested by the electronic states around vortices. Ultimate origin of this phenomenon is attributed to some what hidden frustrations of a spontaneous symmetry broken hexagonal VL on the underlying four-fold crystalline symmetry.Comment: 4 pages, 5 figures, some typos are correcte

Application and Validation of PFGE for Serovar Identification of Leptospira Clinical Isolates

Serovar identification of clinical isolates of Leptospira is generally not performed on a routine basis, yet the identity of an infecting serovar is valuable from both epidemiologic and public health standpoints. Only a small number of reference laboratories worldwide have the capability to perform the cross agglutinin absorption test (CAAT), the reference method for serovar identification. Pulsed-field gel electrophoresis (PFGE) is an alternative method to CAAT that facilitates rapid identification of leptospires to the serovar level. We employed PFGE to evaluate 175 isolates obtained from humans and animals submitted to the Centers for Disease Control and Prevention (CDC) between 1993 and 2007. PFGE patterns for each isolate were generated using the NotI restriction enzyme and compared to a reference database consisting of more than 200 reference strains. Of the 175 clinical isolates evaluated, 136 (78%) were identified to the serovar level by the database, and an additional 27 isolates (15%) have been identified as probable new serovars. The remaining isolates yet to be identified are either not represented in the database or require further study to determine whether or not they also represent new serovars. PFGE proved to be a useful tool for serovar identification of clinical isolates of known serovars from different geographic regions and a variety of different hosts and for recognizing potential new serovars

Saskatchewan Northern Health Authorities, Saskatchewan Correspondence and reprints: Dr James Irvine, Population Health Unit, Athabasca Health Authority, Keewatin Yatthé Health Region and Mamawetan Churchill River Health Region, Box 6000, LaRonge, Saskatch

A 51-year-old Aboriginal woman from northern Saskatchewan presented to a local family medical clinic in early October 2006 with a three-day history of left knee pain. Her vital signs included a blood pressure of 114/70 mmHg, a heart rate of 100 beats/min and a respiratory rate of 20 breaths/min. Her temperature was not documented. On examination, her knee was warm and painful, and an effusion was noted. Approximately six weeks prior, she had fallen on her right knee while walking. This injury was complicated by hemarthrosis and effusion, requiring needle drainage on two occasions. In addition, she had a history of pain, swelling and erythema involving her shoulder joint. Her past history was significant for alcohol abuse and unstable social and housing conditions. The laboratory results showed the followingwhite blood cell (WBC) count 9.8×10 9 /L (normal 0.2×10 9 /L to 10×10 9 /L); granulocyte count 8.8×10 9 /L (normal 2×10 9 /L to 7.8×10 9 /L); hemoglobin (Hb) level 102 g/L (normal 120 g/L to 180 g/L) and platelet count 68×10 9 /L (normal 150×10 9 /L to 450×10 9 /L). A presumptive diagnosis of inflammatory arthritis was made, and she was given indomethacin 50 mg three times a day for her symptoms. Two days later, the patient became progressively more confused, disoriented and unresponsive to questions. She was brought by ambulance to the local emergency department where her temperature was 38.8°C, pulse 98 beats/min, blood pressure 140/83 mmHg and respiratory rate 32 breaths/min. Her Glasgow coma scale score was 6. She was unresponsive to verbal commands but responsive to painful stimuli. Bruising was noted on both legs, and a large area of erythema was noted around the left knee. Her respiratory examination was unremarkable. Laboratory results showed the following -WBC count 3. 135 U/L) and creatine kinase isoenzyme -MB level 28 U/L (normal 0 U/L to 16 U/L). An evolving neurological condition was thought to be the primary diagnosis. Initial management included intravenous fluid (200 mL/h), cefotaxime 2 g administered intravenously, and blood cultures. She was transferred by air to the Royal University Hospital in Saskatoon, Saskatchewan. During the 1 h flight to Saskatoon, the area of erythema on her left leg tripled in size, and 3 L of intravenous fluids and dopamine were required to stabilize her blood pressure. On arrival, she was noted to be diffusely rigid with no response to painful stimuli. Her temperature was 39°C. She had rigors, peripheral mottling, absence of peripheral pulses, bronchial breath sounds over the right middle lobe, and erythema and target-like lesions over her left knee. Laboratory evaluation on admission showed the following -WBC count 3.

Human Leptospirosis Caused by a New, Antigenically Unique Leptospira Associated with a Rattus Species Reservoir in the Peruvian Amazon

As part of a prospective study of leptospirosis and biodiversity of Leptospira in the Peruvian Amazon, a new Leptospira species was isolated from humans with acute febrile illness. Field trapping identified this leptospire in peridomestic rats (Rattus norvegicus, six isolates; R. rattus, two isolates) obtained in urban, peri-urban, and rural areas of the Iquitos region. Novelty of this species was proven by serological typing, 16S ribosomal RNA gene sequencing, pulsed-field gel electrophoresis, and DNA-DNA hybridization analysis. We have named this species “Leptospira licerasiae” serovar Varillal, and have determined that it is phylogenetically related to, but genetically distinct from, other intermediate Leptospira such as L. fainei and L. inadai. The type strain is serovar Varillal strain VAR 010T, which has been deposited into internationally accessible culture collections. By microscopic agglutination test, “Leptospira licerasiae” serovar Varillal was antigenically distinct from all known serogroups of Leptospira except for low level cross-reaction with rabbit anti–L. fainei serovar Hurstbridge at a titer of 1∶100. LipL32, although not detectable by PCR, was detectable in “Leptospira licerasiae” serovar Varillal by both Southern blot hybridization and Western immunoblot, although on immunoblot, the predicted protein was significantly smaller (27 kDa) than that of L. interrogans and L. kirschneri (32 kDa). Isolation was rare from humans (2/45 Leptospira isolates from 881 febrile patients sampled), but high titers of MAT antibodies against “Leptospira licerasiae” serovar Varillal were common (30%) among patients fulfilling serological criteria for acute leptospirosis in the Iquitos region, and uncommon (7%) elsewhere in Peru. This new leptospiral species reflects Amazonian biodiversity and has evolved to become an important cause of leptospirosis in the Peruvian Amazon

Methicillin sensitive Staphylococcus aureus producing Panton-Valentine leukocidin toxin in Trinidad & Tobago: a case report

<p>Abstract</p> <p>Introduction</p> <p>Certain <it>Staphylococcus aureus </it>strains produce Panton-Valentine leukocidin, a toxin that lyses white blood cells causing extensive tissue necrosis and chronic, recurrent or severe infection. This report documents a confirmed case of methicillin-sensitive <it>Staphylococcus aureus </it>strain harboring Panton-Valentine leukocidin genes from Trinidad and Tobago. To the best of our knowledge, this is the first time that such a case has been identified and reported from this country.</p> <p>Case presentation</p> <p>A 13-year-old Trinidadian boy of African descent presented with upper respiratory symptoms and gastroenteritis-like syptoms. About two weeks later he was re-admitted to our hospital complaining of pain and weakness affecting his left leg, where he had received an intramuscular injection of an anti-emetic drug. He deteriorated and developed septic arthritis, necrotizing fasciitis and septic shock with acute respiratory distress syndrome, leading to death within 48 hours of admission despite intensive care treatment. The infection was caused by <it>S. aureus</it>. Bacterial isolates from specimens recovered from our patient before and after his death were analyzed using microarray DNA analysis and <it>spa </it>typing, and the results revealed that the <it>S. aureus </it>isolates belonged to clonal complex 8, were methicillin-susceptible and positive for Panton-Valentine leukocidin. An autopsy revealed multi-organ failure and histological tissue stains of several organs were also performed and showed involvement of his lungs, liver, kidneys and thymus, which showed Hassal's corpuscles.</p> <p>Conclusion</p> <p>Rapid identification of Panton-Valentine leukocidin in methicillin-sensitive <it>S. aureus </it>isolates causing severe infections is necessary so as not to miss their potentially devastating consequences. Early feedback from the clinical laboratories is crucial.</p

Methicillin sensitive Staphylococcus aureus producing Panton-Valentine leukocidin toxin in Trinidad & Tobago: a case report

<p>Abstract</p> <p>Introduction</p> <p>Certain <it>Staphylococcus aureus </it>strains produce Panton-Valentine leukocidin, a toxin that lyses white blood cells causing extensive tissue necrosis and chronic, recurrent or severe infection. This report documents a confirmed case of methicillin-sensitive <it>Staphylococcus aureus </it>strain harboring Panton-Valentine leukocidin genes from Trinidad and Tobago. To the best of our knowledge, this is the first time that such a case has been identified and reported from this country.</p> <p>Case presentation</p> <p>A 13-year-old Trinidadian boy of African descent presented with upper respiratory symptoms and gastroenteritis-like syptoms. About two weeks later he was re-admitted to our hospital complaining of pain and weakness affecting his left leg, where he had received an intramuscular injection of an anti-emetic drug. He deteriorated and developed septic arthritis, necrotizing fasciitis and septic shock with acute respiratory distress syndrome, leading to death within 48 hours of admission despite intensive care treatment. The infection was caused by <it>S. aureus</it>. Bacterial isolates from specimens recovered from our patient before and after his death were analyzed using microarray DNA analysis and <it>spa </it>typing, and the results revealed that the <it>S. aureus </it>isolates belonged to clonal complex 8, were methicillin-susceptible and positive for Panton-Valentine leukocidin. An autopsy revealed multi-organ failure and histological tissue stains of several organs were also performed and showed involvement of his lungs, liver, kidneys and thymus, which showed Hassal's corpuscles.</p> <p>Conclusion</p> <p>Rapid identification of Panton-Valentine leukocidin in methicillin-sensitive <it>S. aureus </it>isolates causing severe infections is necessary so as not to miss their potentially devastating consequences. Early feedback from the clinical laboratories is crucial.</p

Livestock-associated Methicillin-Resistant Staphylococcus aureus Sequence Type 398 in Humans, Canada

Recent emergence of infections resulting from this strain is of public health concern