Pseudochrobactrum algeriensis sp. nov., isolated from lymph nodes of Algerian cattle.

Three Gram-negative, rod-shaped, oxidase-positive, non-spore-forming, non-motile strains (C130915_07T, C150915_16 and C150915_17) were isolated from lymph nodes of Algerian cows. On the basis of 16S rRNA gene and whole genome similarities, the isolates were almost identical and clearly grouped in the genus Pseudochrobactrum. This allocation was confirmed by the analysis of fatty acids (C19:cyclo, C18 : 1, C18 : 0, C16 : 1 and C16 : 0) and of polar lipids (major components: phosphatidylethanolamine, ornithine-lipids, phosphatidylglycerol, cardiolipin and phosphatidylcholine, plus moderate amounts of phosphatidylmonomethylethanolamine, phosphatidyldimethylethanolamine and other aminolipids). Genomic, physiological and biochemical data differentiated these isolates from previously described Pseudochrobactrum species in DNA relatedness, carbon assimilation pattern and growth temperature range. Thus, these organisms represent a novel species of the genus Pseudochrobactrum, for which the name Pseudochrobactrum algeriensis sp. nov. is proposed (type strain C130915_07T=CECT30232T=LMG 32378T).

The CO2-dependence of Brucella ovis and Brucella abortus biovars is caused by defective carbonic anhydrases.

Brucella bacteria cause brucellosis, a major zoonosis whose control requires efficient diagnosis and vaccines. Identification of classical Brucella spp. has traditionally relied on phenotypic characterization, including surface antigens and 5-10% CO2 necessity for growth (CO2-dependence), a trait of Brucella ovis and most Brucella abortus biovars 1-4 strains. Although molecular tests are replacing phenotypic methods, CO2-dependence remains of interest as it conditions isolation and propagation and reflects Brucella metabolism, an area of active research. Here, we investigated the connection of CO2-dependence and carbonic anhydrases (CA), the enzymes catalyzing the hydration of CO2 to the bicarbonate used by anaplerotic and biosynthetic carboxylases. Based on the previous demonstration that B. suis carries two functional CAs (CAI and CAII), we analyzed the CA sequences of CO2-dependent and -independent brucellae and spontaneous mutants. The comparisons strongly suggested that CAII is not functional in CO2-dependent B. abortus and B. ovis, and that a modified CAII sequence explains the CO2-independent phenotype of spontaneous mutants. Then, by mutagenesis and heterologous plasmid complementation and chromosomal insertion we proved that CAI alone is enough to support CO2-independent growth of B. suis in rich media but not of B. abortus in rich media or B. suis in minimal media. Finally, we also found that insertion of a heterologous active CAII into B. ovis reverted the CO2-dependence but did not alter its virulence in the mouse model. These results allow a better understanding of central aspects of Brucella metabolism and, in the case of B. ovis, provide tools for large-scale production of diagnostic antigens and vaccines.

Serological survey of cattle toxoplasmosis in Medea, Algeria.

Toxoplasmosis is an important zoonotic disease transmitted to humans and warm-blooded animals by a ubiquitous parasite Toxoplasma gondii. One of the most common sources of human infection is the ingestion of tissue cysts through raw or undercooked meat. The present study was conducted to investigate a serological survey of Toxoplasma antibodies in cattle from Medea (North of Algeria). Serum samples were obtained from 295 clinically healthy cattle (261 females and 34 males). All cattle sera were tested for antibodies to T. gondii using the Modified Agglutination Test (MAT). According to MAT results, and taking 1:25 as the cut-off value, antibodies were found in 13 (4.4%) of 295 bovine sera. Five cattle had an antibody titer of 1:25; 6 of 1:50 and 2 of 1:100. More serological surveys are necessary to better understand the epidemiological status of toxoplasmosis in cattle and other ruminants.

The characterization of Brucella strains isolated from cattle in Algeria reveals the existence of a B. abortus lineage distinct from European and Sub-Saharan Africa strains.

Brucellosis is a zoonosis caused by bacteria of the genus Brucella that causes important economic losses and human suffering worldwide. Brucellosis control requires an understanding of the Brucella species circulating in livestock and humans and, although prevalent in African countries of the Mediterranean basin, data for this area are mostly restricted to isolates obtained from humans and small ruminants. Here, we report the characterization of twenty-four Brucella strains isolated from Algerian cattle. Bruce-ladder multiplex PCR and conventional biotyping showed that Algerian cattle are infected mostly by B. abortus biovar 3, and to less extent by B. abortus biovar 1 and B. melitensis biovar 3. Extended AMOS-ERY PCR showed that all Algerian B. abortus biovar 3 strains were of the subgroup 3b. Although by multi locus variable number of tandem repeats analysis (MLVA) most isolates were closer to the European counterparts, five strains displayed characteristics distinct from the European isolates and those of countries across the Sahara, including three repetitions of marker Bruce55. These five strains, plus an earlier isolate from an Algerian human patient, may represent a lineage close to clades previously described in Africa. These data provide the basis for additional molecular epidemiology studies in northern Africa and indicate that further bacteriological and molecular investigations are necessary for a complete understanding of the epidemiology of cattle brucellosis in countries north and south of the Sahara.

First genetic characterization of Toxoplasma gondii in stray cats from Algeria.

Toxoplasmosis is a parasitic disease with worldwide distribution and a major public health problem. In Algeria, no data are currently available about genotypes of Toxoplasma gondii isolated from animals or humans. The present study assesses for the first time the seroprevalence of toxoplasmosis in stray cats, and provides molecular characterization of T. gondii strains circulating in this feline population in Algiers, the capital city of Algeria. Sera from 96 stray cats were tested for the presence of antibodies against T. gondii using the modified agglutination test. The seroprevalence was 50% (48/96) using 1:6 as the positivity cut-off. Different organs samples from stray cats, including heart samples, were tested for the presence of Toxoplasma DNA using real-time PCR. T. Gondii DNA was detected in 90.6% (87/96) of hearts. Of these parasitic DNAs, 22 were submitted to genotyping through the analysis of 15 microsatellite markers. The identified genotypes (12 of 22) mainly belonged to the type II lineage.