Renato Giulio Zanoni

European multicenter study on antimicrobial resistance in bacteria isolated from companion animal urinary tract infections

BackgroundThere is a growing concern regarding the increase of antimicrobial resistant bacteria in companion animals. Yet, there are no studies comparing the resistance levels of these organisms in European countries. The aim of this study was to investigate geographical and temporal trends of antimicrobial resistant bacteria causing urinary tract infection (UTI) in companion animals in Europe. The antimicrobial susceptibility of 22 256 bacteria isolated from dogs and cats with UTI was determined. Samples were collected between 2008 and 2013 from 16 laboratories of 14 European countries. The prevalence of antimicrobial resistance of the most common bacteria was determined for each country individually in the years 2012–2013 and temporal trends of bacteria resistance were established by logistic regression.ResultsThe aetiology of uropathogenic bacteria differed between dogs and cats. For all bacterial species, Southern countries generally presented higher levels of antimicrobial resistance compared to Northern countries. Multidrug-resistant Escherichia coli were found to be more prevalent in Southern countries. During the study period, the level of fluoroquinolone-resistant E. coli isolated in Belgium, Denmark, France and the Netherlands decreased significantly. A temporal increase in resistance to amoxicillin-clavulanate and gentamicin was observed among E. coli isolates from the Netherlands and Switzerland, respectively. Other country-specific temporal increases were observed for fluoroquinolone-resistant Proteus spp. isolated from companion animals from Belgium.ConclusionsThis work brings new insights into the current status of antimicrobial resistance in bacteria isolated from companion animals with UTI in Europe and reinforces the need for strategies aiming to reduce resistance.

Epidemiological survey on Cryptosporidium in an Equine Perinatology Unit

The present study aims to evaluate the prevalence, pattern of spread and risk factors for the transmission of cryptosporidiosis in foals and mares hospitalized in a University Equine Perinatology Unit, where a new subtype family of Cryptosporidium horse genotype was described by Caffara et al. (2013). Mares (36) and foals (37) hospitalized during the 2012 foaling season were included. Multiple sampling from each animal was performed (a total of 305 stool samples were collected). One hundred and eleven environmental samples (gauze swabs) were also collected before and after the breeding season. Fourteen foals were found positive for Cryptosporidium spp. by PCR in at least one sample; a total of 35 foal stool specimens were confirmed for the presence of the protozoa. Instead none of the stool specimens from mares were found positive. PCR-RFLP analysis shows Cryptosporidium parvum in 5 stool samples and Cryptosporidium horse genotype in 21. In 9 specimens, from 4 different foals, the profile was suggestive for a mixed infection. The subtyping at gp60 locus showed 2 strains as members of the subtype family IId and six of the subfamily IIa of C. parvum. Twenty isolates were identified as Cryptosporidium horse genotype subtype VIaA15G4. Five gauze swabs collected from the walls of the boxes where the animals were hosted out of 111 environmental samples examined were PCR positive for Cryptosporidium spp. Cryptosporidium parvum was detected in one sample collected before the foaling season, while Cryptosporidium horse genotype profile was observed in 4 wall samples collected at the end of the 2012 foaling season. The prevalence observed in foals (37.8%) was higher than that reported in other studies. These features and the diffusion of the same genotype point out as the EPU, where critically ill foals are hospitalized, can support the spread of cryptosporidiosis. Therefore, the manual tasks and the activities carried out in these facilities are of great importance, as they might favor the diffusion of the infection.

Helicobacter apri sp. nov., isolated from wild boars

Three isolates (A19T, C21 and F12) with spiral-shaped cells and one bipolar sheathed flagellum were obtained from gastric mucosa and caecal contents of three different wild boars (Sus scrofa) and subjected to a polyphasic taxonomic study. A genus-specific PCR showed that these isolates belonged to the genus Helicobacter. Phylogenetic analysis based on 16S rRNA, 60-kDa heat-shock protein (HSP60) and atpA genes demonstrated they formed a novel lineage within this genus. Pairwise 16S rRNA, HSP60 and atpA gene sequence comparisons of the three isolates revealed 99.7, 99.4 and 99.9 % similarity, respectively, among the three isolates; the 16S rRNA gene of isolate A19T shared 98.5 % sequence similarity with its nearest validly named neighbouring species, Helicobacter mastomyrinus (to the type strain MIT 97-5577T). The taxonomic uniqueness of the wild boar isolates was confirmed by protein analysis performed by matrix-assisted laser desorption/ionization time-of-flight MS and by a distinctive biochemical profile. These data indicated that isolates A19T, C21 and F12 represent a novel taxon, for which the name Helicobacter apri sp. nov. is proposed, with isolate A19T (=DSM 28990T=LMG 28471T) as the type strain.

Rapid diagnosis of strangles (Streptococcus equi subspecies equi) using PCR.

Strangles is one of the most common equine infectious diseases with serious health, welfare and socio-economic impact. However, the detection of Streptococcus equi subspecies equi can be challenging and persistently infected carriers are common. Furthermore, the use of classical microbiology can result in an underestimation of the prevalence of the disease. The difficulties associated with the slow diagnosis of Strangles can result in rapid spread of the disease. Therefore, rapid and economical diagnostic tests are urgently required. Here, two multiplex assays, were developed and validated for the detection of S. equi and S. equi subspecies zooepidemicus, the most common differential diagnosis. Using 59 S. equi and 59 S. zooepidemicus strains collected from various geographical areas, the PCR tests demonstrated a sensitivity of 95% and a specificity of 98%. Furthermore, the assay can be performed directly from clinical swabs. Thus, the assays designed here provide a rapid, reliable and economical solution for the diagnosis of Strangles.

FIRST ISOLATION OF TENACIBACULUM MARITIMUM IN A CAPTIVE SAND TIGER SHARK (CARCHARIAS TAURUS)

Abstract This report describes a case of the first isolation of Tenacibaculum maritimum from a captive-bred adult female sand tiger shark (Carcharias taurus) housed at the Cattolica Aquarium (Italy). The animal showed, between the second dorsal fin and the precaudal pit, skin lesions characterized by the presence of abundant whitish necrotic tissue. Through routine bacteriological examination, a bacterium was isolated from a skin lesion and subsequently identified as T. maritimum by phenotypic characters and species-specific polymerase chain reaction. The antimicrobial sensitivity of the isolated strain was evaluated for 11 antimicrobial agents by disk diffusion method. Antibiotic therapy was conducted with enrofloxacin at 10 mg kg−1 i.m. on alternate days for 10 days. One month after the end of treatment skin lesions showed complete resolution and the shark recovered completely. The case presented here represents the first report of infection by T. maritimum in a sand tiger shark and highlights the potential pathogenic role of this microorganism in elasmobranchs kept in an aquarium.

A comparison of the reliability of two gene targets in loop-mediated isothermal amplification assays for detecting leptospiral DNA in canine urine.

We compared 2 novel loop-mediated isothermal amplification (LAMP) assays that target either the 16S ribosomal RNA (rrs) gene or the gene encoding a 32-kDa leptospiral lipoprotein (lipL32) in order to assess the effect of the target on the accuracy of the LAMP assays. The most sensitive assay was the rrs assay with a limit of detection (LOD) of 1.2 × 101 genome equivalents per reaction. The novel lipL32 assay showed an LOD of 1.2 × 102 genome equivalents per reaction. Both assays showed adequate specificity when tested against a collection of bacteria commonly found in voided canine urine. However, when field samples were assayed, the rrs assays gave many false-positive results and a poor positive predictive value of 8.33%. In conclusion, even if the LAMP assay is used in low prevalence areas, the lipL32 assay would be preferable. Conversely, the higher analytical sensitivity of the rrs assay could be effectively used as a screening test in endemic areas with high disease prevalence, followed by confirmation of the positive results using the lipL32 assay.

Detection and quantification of Cryptosporidium oocysts in environmental surfaces of an Equine Perinatology Unit

The presence of Cryptosporidium in institutions such as veterinary teaching hospitals, where students and staff are in frequent contact with animals, could represent a serious public health risk. In this study the detection and quantification of the Cryptosporidium oocysts present on the environmental surfaces of an Equine Perinatology Unit (EPU) were investigated. During 3 foaling seasons 175 samples obtained by swabbing an area of the floor and walls of boxes and utility rooms of EPU with sterile gauze, in 3 different moments. Samples were collected at the end of foaling season (July), after washing procedures (September) and after washing and disinfecting procedures, at the beginning of a new foaling season (December). All the samples were subjected to nested-PCR, followed by genotyping and sub-typing methods and to qPCR, allowing the oocyst quantification. Cryptosporidium spp. was detected in 14 samples, of which 11 were from walls and three were from floors. The highest number of oocysts was found in a sample collected from the floor of one utility room used for setting up therapies and treatments. In most cases, oocyst numbers, estimated by qPCR, were reduced or eliminated after washing and disinfecting procedures. The genotyping and sub-typing methods allowed identification of 2 subtypes of C. parvum (IIaA15G2R1 and IIdA23G1) and 1 of Cryptosporidium horse genotype (VIaA15G4) that were described in foals hospitalized at the EPU in the same years. The results of the present study show that qPCR can be used to evaluate Cryptosporidium contamination of environmental surfaces of a veterinary teaching hospital and the efficacy of the disinfection procedures.

A comparison of two real-time polymerase chain reaction assays using hybridization probes targeting either 16S ribosomal RNA or a subsurface lipoprotein gene for detecting leptospires in canine urine

Leptospires are excreted in the urine of infected animals, and the prompt detection of leptospiral DNA using polymerase chain reaction (PCR) is increasingly being used. However, contradictory data has emerged concerning the diagnostic accuracy of the most popular PCR assays that target either the 16S ribosomal RNA (rrs) or the subsurface lipoprotein (LipL32) genes. In order to clarify the effect of the gene target, a novel hydrolysis probe–based, quantitative real-time PCR (qPCR) assay targeting the LipL32 gene was developed, validated, and then compared directly to the previously described rrs hydrolysis probe–based qPCR using a convenience collection of canine urine samples. The novel LipL32 qPCR assay was linear from 5.9 × 106 to 59 genome equivalents per reaction. Both the LipL32 and the rrs qPCR assays showed a limit of detection of 10 target copies per reaction indicating an approximately equivalent analytical sensitivity. Both assays amplified all 20 pathogenic leptospiral strains tested but did not amplify a representative collection of bacteria commonly found in voided canine urine. When the field samples were assayed, 1 and 5 out of 184 samples yielded an amplification signal in the LipL32 and rrs assays, respectively. Nevertheless, when the limit of detection was considered as the cutoff for interpreting findings, the 4 discordant cases were judged as negative. In conclusion, our study confirmed that both LipL32 and rrs are suitable targets for qPCR for the detection of leptospiral DNA in canine urine. However, the rrs target requires the mandatory use of a cutoff value in order to correctly interpret spurious amplifications.

Antimicrobial susceptibility of Campylobacter cuniculorum isolated from rabbits reared in intensive and rural farms

The present study aimed to investigate the antimicrobial susceptibility in Campylobacter cuniculorum. To do so, 29 isolates from rabbits reared in 18 intensive and 11 rural farms not epidemiologically correlated were tested. Minimum inhibitory concentration of 8 antimicrobial agents was determined using the agar dilution method recommended by the Clinical and Laboratory Standards Institute (Wayne, PA, USA), modified – for what supplements in the base medium and incubation conditions concern – for C. cuniculorum isolates. The isolates obtained from rural farming resulted susceptible to all the antimicrobial agents tested, with the exception of one isolate resistant to nalidixic acid. All the isolates obtained from intensively farmed rabbits were sensitive to chloramphenicol and ampicillin; 16 isolates were resistant to tetracycline; 15 to nalidixic acid and erythromycin; 13 and 10 isolates to ciprofloxacin and enrofloxacin, respectively; and only 1 to gentamicin. The resistance of several isolates to macrolides and fluoroquinolones, which are the drugs of choice in treatment of human campylobacteriosis, could pose a risk to human health if a pathogenic role of C. cuniculorum was demonstrated.