Antimicrobial activity of the ornamental species Salvia corrugata, a potential new crop for extractive purposes

As a part of our search for biologically active compounds from cultivated Salvia spp. we investigated Salvia corrugata Vahl. The activity of two isolated icetaxane diterpene quinones, fruticuline A and demethylfruticuline A, was assessed against 46 bacterial pathogens, mostly resistant to several primary antibiotics. The MIC for all the inhibited Gram-positive pathogens tested showed a very narrow distribution and ranged from 32 to 64 mg/L, regardless of their resistance patterns to other antibiotics. Demethylfruticuline A was shown to be highly bactericidal (>3 log(10) CFU decrease within 24 h) against Staphylococcus aureus and S. epidermidis and bacteriostatic against Enterococcus faecalis and E. faecium. Fruticuline A manifested bacteriostatic activity against all tested strains. S. corrugata can be viewed as an interesting source for these diterpenes, which, if well tolerated in vivo, may represent new medical agents useful for the treatment of serious infections caused by resistant Gram-positive pathogens.     

Using Fourier transform infrared (FT-IR) absorbance spectroscopy and multivariate analysis to study the effect of chlorine-induced bacterial injury in water

The effect of chlorine-induced bacterial injury on spectral features using Fourier transform infrared (FT-IR) absorbance spectroscopy was studied using a mixed bacterial culture of (1:1) ca. 500 CFU/mL each Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 15442 in 0.9% saline. Bacterial cells were treated with 0, 0.3, or 1.0 ppm of initial free chlorine (21 degrees C, 1 h of contact time). Chlorine-injured and dead bacterial cells retained the ATR spectral properties of uninjured or live cells in the region of C-O-C stretching vibrations of polysaccharides, indicative of the cell wall peptidoglycan layer and lipopolysaccharide outer leaflet. This confirms the observations of others that extensive bacterial membrane damage is not a key factor in the inactivation of bacteria by chlorine. The bactericidal effect of chlorine caused changes in the spectral features of bacterial ester functional groups of lipids, structural proteins, and nucleic acids, with apparent denaturation reflected between 1800 and 1300 cm (-1) for injured bacterial cells. Three-dimensional principal component analysis (PCA) showed distinct segregation and clustering of chlorine-treated and untreated cells. Cells exposed to chlorine at 0.3 or 1.0 ppm could be distinguished from the untreated control 73 and 80% of the time, respectively, using soft independent modeling of class analogy (SIMCA) analysis. This study suggests that FT-IR spectroscopy may be applicable for detecting the presence of injured and viable but not culturable (VBNC) waterborne pathogens that are underestimated or not discernible using conventional microbial techniques.     

Selective growth inhibition of human leukemia and human lymphoblastoid cells by resveratrol via cell cycle arrest and apoptosis induction

There is great interest in the potential chemopreventive activity of resveratrol against human cancers. However, there are conflicting results on its growth inhibitory effect on normal cells. This project examined the differential effect of resveratrol at physiologically relevant concentrations on nonmalignant (WIL2-NS) and malignant (HL-60) cell lines and compared the underlying mechanisms via cell cycle modulation, apoptosis induction, and genotoxicity potential. Twenty-four hours of exposure to resveratrol was toxic to WIL2-NS and HL-60 cells in a dose-dependent manner. WIL2-NS cells regrew 5 times more than HL-60 cells by 120 h after the removal of 100 microM resveratrol (p < 0.05). Furthermore, significant alterations in cell cycle kinetics were induced by resveratrol in HL-60 cells, but were to a lesser extent for WIL2-NS cells. The proportion of apoptosis was also 3 times higher in HL-60 cells as compared to WIL2-NS cells for 100 microM resveratrol (p < 0.05). In conclusion, resveratrol preferentially inhibited the growth of HL-60 cells via cell cycle modulation and apoptosis induction and subsequently directed the cells to irreversible cell death, whereas the effect on WIL2-NS cells was largely reversible.     

Absence of three known benzimidazole resistance mutations in Trichostrongylus tenuis, a nematode parasite of avian hosts

Benzimidazole (BZ) resistance is widespread in nematode parasites of livestock, but very little is known about the levels of BZ resistance in parasites with avian hosts. We investigated BZ resistance in Trichostrongylus tenuis, a nematode parasite of red grouse, Lagopus lagopus scotica. BZ anthelmintics had been in use in this system for up to 15 years, yet existing phenotypic evidence for resistance was inconclusive. We screened 1530 individuals from 14 populations at the principal β-tubulin locus for BZ resistance (isotype 1, residue 200) and 940 of these at two further resistance sites (isotype 1, residue 167; isotype 2, residue 200). No BZ resistant genotypes were found. Alternative mechanisms may be responsible for BZ resistance in this system, or the method and timing of treatments may reduce selection pressure for BZ resistance by creating substantial refugia for susceptible genotypes.     

Prevalence of Ehrlichia canis, Anaplasma platys, Babesia canis vogeli, Hepatozoon canis, Bartonella vinsonii berkhoffii, and Rickettsia spp. in dogs from Grenada

To identify the tick-borne pathogens in dogs from Grenada, we conducted a serologic survey for Ehrlichia canis in 2004 (104 dogs) and a comprehensive serologic and molecular survey for a variety of tick-borne pathogens in 2006 (73 dogs). In 2004 and 2006, 44 and 32 dogs (42.3% and 43.8%) were seropositive for E. canis, respectively. In 2006, several tick-borne pathogens were identified by serology and PCR. DNA of E. canis, Anaplasma platys, Babesia canis vogeli, Hepatozoon canis, and Bartonella sp. were identified in 18 (24.7%), 14 (19.2%), 5 (7%), 5 (7%), and 1 (1.4%) dogs, respectively. Six (8.2%) dogs were seropositive for Bartonella vinsonii subsp. berkhoffii. All dogs were seronegative and PCR-negative for Rickettsia spp. Coinfection with two or three pathogens was observed in eight dogs. Partial 16S rRNA E. canis and A. platys sequences were identical to sequences in GenBank. Partial 18S rRNA gene sequences from the Grenadian H. canis were identical to each other and had one possible mismatch (ambiguous base) from H. canis detected from Spain and Brazil. Grenadian B. c. vogeli sequences were identical to B. c. vogeli from Brazil and Japan. All of the detected pathogens are transmitted, or suspected to be transmitted, by Rhipicephalus sanguineus. Results of this study indicate that dogs from Grenada are infected with multiple tick-borne pathogens; therefore, tick-borne diseases should be included as differentials for dogs exhibiting thrombocytopenia, leukopenia, fever, or lethargy. One pathogen, E. canis, is also of potential public health significance.     

Diphtheroid colitis in a Boa constrictor infected with amphibian Entamoeba sp

A female boa (Boa constrictor) from a zoological collection was submitted for necropsy after sudden death. Prominent pathological findings included a diphtheroid colitis, endoparasitism, focal pneumonia and inclusion bodies typical for inclusion body disease (IBD). In the colon entamoebae were identified, which differed in size and distribution from Entamoeba invadens. Gene sequence analysis of the 18S ribosomal RNA revealed 100% similarity with an Entamoeba species from the African bullfrog (Pyxicephalus adspersus), probably Entamoeba ranarum. The snake was possibly immunosuppressed, and the source of infection remains unclear. This is the first report of an infection with an amphibian Entamoeba species associated with colitis in a snake.     

Real-time PCR-based prevalence study, infection follow-up and molecular characterization of canine hemotropic mycoplasmas

Hemotropic mycoplasmas (hemoplasmas) have been reported in several mammalian species including dogs. Infections may lead to hemolytic anemia, but investigations in the dog had been hampered by the lack of adequate diagnostic methods. Only recently sensitive PCR-based assays were reported for the two canine hemoplasmas, Mycoplasma haemocanis and Candidatus Mycoplasma haematoparvum. By applying these assays, 15.4% of 460 dogs from the south of France tested hemoplasma positive. It was hypothesized that this high prevalence may be associated with the presence of Rhipicephalus sanguineus, a proposed vector for canine hemoplasmas. To address this hypothesis and expand the PCR-based knowledge on canine hemoplasmosis, we investigated dogs in a climatic zone that does not allow for the permanent establishment of R. sanguineus. Blood samples were collected throughout a year from 889 dogs in Switzerland: 1.2% of the dogs tested real-time PCR positive. The infection status was not significantly associated with anemia, age or gender. Phylogenetic analyses of Candidatus M. haematoparvum and M. haemocanis isolates revealed > or =99.8% identity to published sequences. All samples collected from three infected dogs throughout a follow-up period of < or =13 months tested PCR positive. Interestingly, the majority of the infected dogs either had been imported from or had visited regions where R. sanguineus is indigenous. Thus, canine hemoplasma prevalence was found to be low in a country with a climate incompatible with frequent occurrence of R. sanguineus. Nonetheless, veterinarians may expect hemoplasma infections in dogs with a travel history and/or after potential tick vector exposure.     

Nasopharyngeal turbinates in brachycephalic dogs and cats

This retrospective study reports the presence and incidence of nasal turbinates in the nasopharynx (nasopharyngeal turbinates) in a population of brachycephalic dogs and cats exhibiting signs of upper respiratory disease. Medical records were reviewed for 53 brachycephalic dogs and 10 brachycephalic cats undergoing upper airway endoscopy. Nasopharyngeal turbinates were identified in 21% of brachycephalic animals, including 21% of dogs and 20% of cats. Pugs accounted for 32% of all dogs in the study population and 82% of dogs with nasopharyngeal turbinates. The presence of nasopharyngeal turbinates may play a role in upper airway obstruction in the brachycephalic airway syndrome.     

Coccidioidomycosis in dogs and cats: a review

The dimorphic fungi Coccidioides immitis and Coccidioides posadasii are the causative agents of coccidioidomycosis. Dogs and cats residing in and visiting endemic areas are at risk of exposure to infectious arthrospores. The primary infection is pulmonary and frequently results in chronic cough. Disseminated disease is common and causes cutaneous, osseous, cardiac, ocular, nervous system, or other organ disease. Radiographic changes include a variable degree of interstitial pulmonary infiltration, hilar lymphadenopathy, and osseous lesions. Serological titers support the diagnosis, but definitive diagnosis relies on identification of Coccidioides in cytological or tissue samples. Coccidioidomycosis should be considered in any dog or cat that has been potentially exposed during the previous 3 years and is presented with chronic illness, respiratory signs, lameness, lymphadenopathy, nonhealing cutaneous lesions, or neurological, ocular, or cardiac abnormalities.     

Clinical Parelaphostrongylus tenuis infection in two captive American bison (Bison bison)

CASE DESCRIPTION: 2 juvenile (17 and 19 months of age) male American bison (Bison bison) were examined because of acute bilateral hind limb weakness and ataxia; 1 animal also had urinary incontinence. TREATMENT AND OUTCOME: Given the clinical signs and rapid deterioration in the condition of these 2 animals, obtaining a definitive diagnosis was considered essential to minimizing the risk of disease in the remaining bison herd and among other animals at the facility. Therefore, both affected animals were euthanized. At necropsy, no gross abnormalities were seen. Histologic examination of sections of the brains from both animals revealed mild to moderate multifocal aggregates of eosinophils and mononuclear cells in perivascular regions of the meninges and gray matter of the cerebrum, cerebellum, and brainstem. Systematic examination of multiple sections of brain and spinal cord revealed evidence of nematode sections and aberrant parasite migration. CLINICAL RELEVANCE: Findings suggested that CNS migration of Parelaphostrongylus tenuis in American bison may cause clinical signs. These findings have implications for the management of captive bison and free-ranging bison sharing ranges with white-tailed deer (Odocoileus virginianus), the definitive host, and elk (Cervus elaphus canadensis).