Extended-spectrum beta-lactamases-producing gram-negative bacteria in companion animals: action is clearly warranted!

Extended-spectrum beta-lactamases (ESBL)-producing Gram-negative bacteria pose a serious threat to Public Health in human medicine as well as increasingly in the veterinary context worldwide. Several studies reported the transmission of zoonotic multidrug resistant bacteria between food-producing animals and humans, whilst the contribution of companion animals to this scenario is rather unknown. Within the last decades a change in the social role of companion animals has taken place, resulting in a very close contact between owners and their pets. As a consequence, humans may obtain antimicrobial resistant bacteria or the corresponding resistance genes not only from food-producing animals but also via close contact to their pets.This may give rise to bacterial infections with limited therapeutic options and an increased risk of treatment failure. As beta-lactams constitute one of the most important groups of antimicrobial agents in veterinary medicine, retaliatory actions in small animal and equine practices are urgently needed. This review addresses the increasing burden of extended-spectrum beta-lactam resistance among Enterobacteriaceae isolated from companion animals. It should emphasize the urgent need for the implementation of antibiotic stewardship as well as surveillance and monitoring programs of multi resistant bacteria in particular in view of new putative infection cycles between humans and their pets.     

Antimicrobial susceptibility of streptococci from various indications of swine, horses, dogs and cats as determined in the BfT-GermVet monitoring program 2004-2006

A total of 500 streptococci from two indications of swine (beta-haemolytic streptococci from infections of the urinary/genital tract including strains from the mastitis metritis agalactia syndrome as well as S. suis from infections of the central nervous system and the musculoskeletal system), two indications of horses (S. equi from respiratory tract infections and beta-haemolytic streptococci from infections of the genital tract), as well as three indications of dogs and cats (beta-haemolytic streptococci from infections of the respiratory tract, the urinary/genital tract, and skin/ear/mouth) were investigated for their susceptibility to antimicrobial agents. Regardless of the animal origin and indication, the most frequently detected resistance properties were resistances against sulfamethoxazole (20-78%), tetracycline (17-93%) as well as gentamicin (14-79%). Resistance to penicillins or cephalosporins was very rarely detected - if at all.     

Antimicrobial susceptibility of Pseudomonas aeruginosa from dogs and cats as well as Arcanobacterium pyogenes from cattle and swine as determined in the BfT-GermVet monitoring program 2004-2006

During the BfT-GermVet monitoring program, Pseudomonas (P) aeruginosa from dogs and cats (n = 99) as well as Arcanobacterium (A.) pyogenes from cattle and swine (n = 90) were examined for their antimicrobial susceptibility. In general, P. aeruginosa is known to be resistant against many antimicrobial agents whereas A. pyogenes is thought to be susceptible to most agents in-vitro. However, representative and actual minimum inhibitory concentration (MIC) values are missing for both veterinary pathogens. In the present study, MIC values were determined and categorized according to the recommendations given in the Clinical and Laboratory Standards Institute (CLSI) documents M31-A2 and M31-S1. For susceptibility testing of A. pyogenes, the CLSI methodology was slightly modified. Specific breakpoints were not available for most of the antimicrobial agents tested. P. aeruginosa isolates from infections of the skin, ear and mouth as well as the urinary and genital tract of dogs and cats were either resistant or exhibited high MIC values to most antimicrobial agents tested. However, gentamicin resistant isolates were observed in only 27% and 11% (intermediate isolates 29% and 39%), respectively. For the same bacterium/host animal/organ system combinations, enrofloxacin resistance was detected in only 24% and 11% of the isolates (intermediate isolates 49% and 61%). For A. pyogenes, resistance was most prevalent against tetracycline (33%-56%, bovine and porcine isolates) and sulfonamides (26%-40%, bovine isolates).     

Antimicrobial susceptibilities and occurrence of resistance genes in bovine Helcococcus ovis isolates

The aim of the study was to investigate antimicrobial susceptibilities of bovine Helcococcus ovis isolates and to detect genes encoding for H. ovis erythromycin and tetracycline resistance. Twenty-nine isolates were included and the minimal inhibitory concentrations (MICs) of seven antimicrobials were determined using test conditions as given in an approved CLSI guideline for the pyridoxal-dependent Abiotrophia spp. and Granulicatella spp. Furthermore, the macrolide resistance phenotype was examined by the erythromycin-clindamycin double-disk test (D-zone test). Erythromycin MICs of ≥ 8 μg/ml were found in three (10%) isolates which also presented the macrolide, lincosamide, and streptogramin B (MLS(B)) resistance phenotype, either constitutive or inducible. The erm(B) gene was detected in one of these isolates. Increased tetracycline MICs (≥ 8 μg/ml) were obtained for 24 (83%) isolates, mostly associated with the tet(M) gene alone (n=21) or both the tet(L) and tet(M) genes (n=2). The MICs determined for penicillin, ampicillin, amoxicillin-clavulanic acid, and cephalothin did not indicate resistance to these antimicrobials. The study suggests that resistance to MLS(B) antimicrobials and tetracycline is frequent in H. ovis. Moreover, this is the first report about occurrence of the resistance genes erm(B), tet(L), and tet(M) in the Helcococcus genus.     

Climate and groundwater recharge during the last glaciation in an ice-covered region

A multitracer study of a small aquifer in northern Switzerland indicates that the atmosphere in central Europe cooled by at least 5 degreesC during the last glacial period. The relation between oxygen isotope ratios (delta18O) and recharge temperatures reconstructed for this period is similar to the present-day one if a shift in the delta18O value of the oceans during the ice age is taken into account. This similarity suggests that the present-day delta18O-temperature relation can be used to reconstruct paleoclimate conditions in northern Switzerland. A gap in calculated groundwater age between about 17,000 and 25,000 years before the present indicates that during the last glacial maximum, local groundwater recharge was prevented by overlying glaciers.     

Morphological and Apoptotic Comparison of Primordial and Primary Follicles in Cryopreserved Human Ovarian Tissue

There are few reports which were designed to compare the survival rate of human primary follicles with primordial follicles after cryopreservation. This study was designed to evaluate whether such a difference occurs. Human ovarian biopsies were cryopreserved using dimethylsulphoxide/sucrose as the cryoprotectants. Fresh and cryopreserved ovarian samples were evaluated for viability differences between the two types of follicles using the endpoints of histology, ultrastructure and DNA fragmentation. In comparison with fresh ovarian tissue (83.9% ± 10.0%), the percentage of morphologically normal primordial follicles was not significantly different in cryopreserved tissue (73.9% ± 17.2%). However, a lower percentage of primary follicles with normal morphology was seen in the cryopreserved group (43.3% ± 25.7% vs 74.8% ± 19.4% for the fresh group). Transmission electron microscopy revealed that the cryopreservation did not appear to affect the structural integrity of primordial follicles; however, varying ultrastructural damage to the cytoplasm was observed in the majority of the cryopreserved primary follicles. Using a DNA fragmentation assay, the percentage of apoptotic primordial and primary follicles in the unfrozen (26.3% and 20%) and frozen (23.3% and 25%) ovarian tissue was similar. A higher proportion of primary follicles, compared to primordial follicles, suffer histological damage after slow freezing.     

Performance of complement fixation test and confirmatory immunoblot as two-cascade testing approach for serodiagnosis of glanders in an endemic region of South East Asia

Various serological tests were used for the diagnosis of glanders in the past but still complement fixation test (CFT) is the internationally prescribed test for trading equines. A new immunoblot (IB) technique has recently been introduced to overcome the well known shortcomings of CFT i. e. a considerable number of false positive and negative results and anticomplementary effects of sera. The objective of this study was the comparative evaluation of two glanders CFT antigens commercially available at Central Veterinary Institute ofWageningen UR, Lelystad, NL (CIDC) and at c.c.pro GmbH, Oberdorla, DE (c.c.pro) in a glanders endemic area regarding specificity and sensitivity. A total of 1678 serum samples from the endemic region (Province Punjab, Pakistan) and a non-endemic area (Germany) were analysed. All sera tested positive or suspicious with CFT were analysed by the confirmatory IB to exclude CFT false positive results. Both CFT antigens showed 100% sensitivity. The use of CIDC or c.c.pro antigen resulted in specificities of 77.45% or 75.71% for sera from endemic area and 93.75% or 94.79% for sera from non-endemic areas, respectively. The results demonstrate the different performances of identical tests in different epidemiologically settings. Based on these results, the combined use of CFT and IB is highly suggestive for the serodiagnosis of glanders. Good agreement was calculated between CFT (using either c.c.pro or CIDC antigen) and immunoblot.     

Phenotypical characterization of peripheral blood leucocytes in the newborn calf

The present study was undertaken to establish reference values for the composition of blood leucocyte populations in neonatal calves by differential leucocyte counts and immunophenotyping. Neonatal calves 1 h post partum (p.p.) were found to have a very high absolute number of granulocytes while the number of peripheral blood mononuclear cells was lower than in calves aged 3-9 weeks. The relative numbers of T cell subpopulations were similar in newborn and older calves, but newborn calves had lower percentages of B cells and MHC class II positive cells. Within the first 4 h of life the relative numbers of CD2+, CD6+, and CD8+ T cells declined in colostrum-fed as well as in colostrum-deprived calves. In contrast, the percentage of MHC class II positive cells and monocytes increased from 1 h to 4 h p.p. particularly in colostrum-fed calves. Although there is some evidence for immaturity of lymphocytes in neonatal calves, the immune system of these animals seems to be fully present at birth.