Canine otitis externa is a common multifactorial condition frequently complicated by bacterial and fungal infections. The increasing prevalence of antimicrobial resistance has reduced the effectiveness of conventional therapies, underscoring the need for alternative treatment strategies. Antimicrobial peptides represent a promising option due to their broad-spectrum activity and low propensity to induce resistance. Among these, the Naja Cardiotoxin Peptide-3 (NCP-3), derived from cardiotoxin 1 of the Chinese cobra (Naja atra subsp. atra), has demonstrated potent bactericidal and fungicidal activity with minimal cytotoxicity. In this study, the in vitro antimicrobial activity of NCP-3 was evaluated against clinical isolates obtained from dogs with otitis externa, including multidrug-resistant bacteria and Malassezia pachydermatis. NCP-3 was effective against all reference tested strains except Proteus mirabilis. Among field strains, the highest bactericidal activity was observed on Staphylococcus pseudintermedius (MBC₅₀=3.1 µg/mL; MBC₉₀=6.3 µg/mL), whereas higher concentrations were required to inhibit Pseudomonadaceae (MBC₅₀=12.5 µg/mL). Neither MBC₅₀ nor MBC₉₀ were achieved for Enterobacteriaceae or M. pachydermatis. Time-kill assays demonstrated rapid bactericidal activity of NCP-3 against both reference and clinical Gram-positive strains, with complete inhibition achieved within five minutes. In contrast, Gram-negative reference strains required longer exposure times, with a partial inhibition only at 120 min. Overall, these findings indicate that NCP-3 exhibits stronger antimicrobial activity against Gram-positive bacteria, including resistant strains, than on Gram-negative bacteria and M. pachydermatis field strains. NCP-3 may therefore represent a promising candidate as therapeutic agent for canine otitis externa caused by Gram-positive pathogens, supporting further investigation into its potential applications in veterinary medicine.

Caprine herpesvirus 1 (CpHV-1), a member of the Herpesvirales order, Herpesviridae family, Alphaherpesvirinae subfamily, and Simplexvirus genus, is classically associated with two distinct clinical syndromes. In kids, CpHV-1 induces severe systemic disease with high morbidity and mortality, whereas in adult goats, the infection leads to genital lesions such as vulvovaginitis or balanoposthitis, with abortions occurring mainly in the second half of gestation. CpHV-1 shares several biological characteristics with human herpesvirus 2, including molecular features, tropism for vaginal epithelium, genital lesion nature, and latency in the sacral ganglia. These features make CpHV-1-infected goats a reliable animal model for studying human herpesvirus-induced genital disease, relevant for pathogenic research, as well as the development of new vaccines and antiviral agents. Recent full sequencing of the CpHV-1 genome has identified at least 10 genes encoding glycoproteins. Among these, glycoprotein D (gD) has been characterized but not yet exploited for immunogenic or diagnostic purposes. In this study, the structural features of CpHV-1 gD were predicted using in silico analysis. A truncated version of gD lacking the transmembrane domain (secreted glycoprotein D [Sec-gD]) was subsequently generated and expressed in mammalian cells, enabling its secretion into the culture medium. Despite the structural modifications, Sec-gD retained a conserved glycosylation pattern, as confirmed by N-glycosylation mutants generation and peptide-N-glycosidase F treatment. Furthermore, the antigenic properties of Sec-gD were preserved, as demonstrated by reverse serum neutralization assays. Notably, the culture supernatant containing Sec-gD was directly usable in diagnostic enzyme-linked immunosorbent assays, supporting its potential as a valuable tool for both diagnostic and immunization strategies.IMPORTANCECaprine herpesvirus 1 (CpHV-1)-infected goats represent a large animal model for studying human herpesvirus-induced genital disease and could be utilized for pathogenic research, as well as for the development of new vaccines and antiviral agents. CpHV-1 glycoprotein D can be efficiently produced and rescued from the supernatant of transfected mammalian cells, retaining its immunogenic properties, and could be used for immunogenic and diagnostic purposes.

Caprine herpesvirus 1 (CpHV-1), a member of the Herpesvirales order, Herpesviridae family, Alphaherpesvirinae subfamily, and Simplexvirus genus, is classically associated to two distinct clinical syndromes. In kids, CpHV-1 induces severe systemic disease with high morbidity and mortality, in adult goats, the infection leads to genital lesions such as vulvovaginitis or balanoposthitis, with abortions occurring mainly in the second half of gestation. CpHV-1 shares several biological characteristics with human herpesvirus 2 (HSV-2), including molecular features, tropism for vaginal epithelium, genital lesion nature and latency in the sacral ganglia. These features make CpHV-1-infected goats a reliable animal model for studying human herpesvirus-induced genital disease, employable for pathogenic research, as well as the development of new vaccines and antiviral agents. Recent full sequencing of CpHV-1 genome has identified at least ten genes encoding glycoproteins. Among these, glycoprotein D (gD) has been characterized but not yet exploited for immunogenic or diagnostic purposes. In this study, the structural features of CpHV-1 gD were predicted using in silico analysis. A truncated version of gD lacking the transmembrane domain (Sec-gD) was subsequently generated and expressed in mammalian cells, enabling its secretion into the culture medium. Despite the structural modifications, Sec-gD retained a conserved glycosylation pattern, as confirmed by PNGase F treatment. Furthermore, the antigenic properties of Sec-gD were preserved, as demonstrated by reverse serum neutralization assays. Notably, the culture supernatant containing Sec-gD was directly usable in diagnostic enzyme-linked immunosorbent assays, supporting its potential as a valuable tool for both diagnostic and immunization strategies. Importance CpHV-1-infected goats represent a large animal model for studying human herpesvirus-induced genital disease, and could be utilized for pathogenic research, as well as for the development of new vaccines and antiviral agents. CpHV-1 gD can be efficiently produced and rescued from the supernatant of transfected mammalian cells, retaining its immunogenic properties and could be employed for immunogenic and diagnostic purposes.

Plant-derived compounds have emerged as potential alternatives to traditional antimicrobials in livestock; however, their application may be limited by degradation in the gastrointestinal tract. Nanoliposome encapsulation offers a strategy to overcome these limitations. In this study, we investigated the effects of nerolidol encapsulation, by evaluating the antimicrobial activity of free-nerolidol (NER), nerolidol-loaded nanoliposomes (LN), and unloaded nanoliposomes (UN) (Lipobox™) using a Time-Kill assay. The cytotoxicity of these formulations was assessed through MTT assay on swine and bovine cell lines. NER was effective against MRSA, Enterococcus faecium, and Lactobacillus acidophilus at all time points, at concentrations ≥62.5, ≥15.63 and ≥1,000 μg/ml, respectively, but was ineffective against Gram-negative bacteria Conversely, LN and UN were effective against all bacteria, showing the best activity at 2,500 μg/ml. LN showed the greatest activity against MRSA up to 6 h while UN on E. faecium up to 4 h (P < 0.05). No difference between LN and UN on Salmonella Typhimurium up to 24 h and on E. coli up to 6 h at this concentration (P > 0.05) was observed. For L. acidophilus, both LN and UN were effective up to 6 h even at the lowest concentration (9.77 μg/ml). NER showed high cytotoxicity on MDBK and IPEC-J2 cells at all doses; while LN and UN were low-toxic at concentrations ≤ 1,250 μg/ml or ≤ 625 μg/ml, respectively. These results suggest that nanoliposomes themselves exhibit dose-dependent antimicrobial and cytotoxicity activity; however, when NER is encapsulated its spectrum of activity its enhanced.

BACKGROUND:Malassezia pachydermatis (MP) is implicated in severe dermatitis and otitis externa (OE) of companion animals and recently gained attention for its increasing resistance to azole compounds. For this reason, developing novel therapeutic strategies is of great interest. In a previous work, we used reference yeast isolates to evaluate several compounds bearing acyl/selenoureido moieties and primary/secondary sulfonamide groups for antifungal activity through organic selenium and carbonic anhydrase inhibition. OBJECTIVES:This work aimed to evaluate the antifungal efficacy of eight selenoureido compounds on 36 clinical MP isolates from dogs, compared to selected azoles, notably ketoconazole (KCZ), miconazole (MCZ) and fluconazole (FCZ). MATERIALS AND METHODS:MIC assays of 5g, 7a, 7c, 7k, 8c, 10c, 11b, 11f, KCZ, MCZ and FCZ were performed on 36 MP field isolates isolated from dogs affected by dermatitis and/or OE in which yeast aetiology was suspected. Minimum 50% and 90% inhibitory concentrations (MIC50 and MIC90) were calculated. MP identification was confirmed with a nested PCR for the internal transcribed spacer region of the rRNA gene. RESULTS:Overall, the MIC50 of the tested compounds on MP field isolates was higher than the MICs obtained on reference MP DSM 6172. Although KCZ showed the lowest MIC50 value, compounds 5g, 7a and 7k showed lower MIC50s than MCZ and FCZ. Five clinical isolates showed a MIC on azoles >MIC90. Compounds 7a (four of five), 10c (three of five) and 8c (three of five) showed lower MIC values on these isolates compared to the tested azoles, suggesting good activity in phenotypically azole-resistant MP. CONCLUSIONS AND CLINICAL RELEVANCE:Considering the increasing azole resistance of the Malassezia genus, selenoureido compounds could represent a potential topical treatment for dog skin and ear mycotic infections.

Antibiotics represent the first line therapy for bovine mastitis. However, the increasing prevalence of multidrug-resistant organisms (MDROs) highlights the need for alternative therapeutic approaches. This study evaluated the antimicrobial and antibiofilm activities of Eucalyptus globulus leaf extract (EGL-L), ursolic acid (UA) and asiatic acid (AA) against Staphylococcus aureus (SA), Streptococcus uberis (SU), Streptococcus agalactiae (SAG), and Enterococcus spp. (EN) isolated from bovine mastitis, 39.7% of which were MDROs. The minimal inhibitory concentration (MIC) assay demonstrated that all the compounds exhibited antimicrobial activity against the tested bacteria, including MDROs. However, EGL-L was less effective (p < 0.001) than UA or AA against field strains. UA was more effective against SAG and SU compared to SA (p < 0.001), whereas AA was more effective against SU than SA (p < 0.001). Conversely, EGL-L exhibited similar inhibitory effects on all bacteria. The biofilm-forming ability of the bacterial strains was also assessed, and the minimal biofilm inhibitory concentrations (MBICs) of the compounds were evaluated for moderate and strong biofilm producers. None of the compounds were able to completely inhibit biofilm formation. However, MBIC80 values within the tested concentration range were achieved for 15 out of 32 strains with EGL-L and for 27 out of 32 strains with UA and AA. These findings highlight a promising alternative to conventional antimicrobials for AA and UA, showing potential for topical intramammary use for the control and prevention of bovine mastitis, especially because of their efficacy against biofilm formation. Future research should focus on toxicity assessments and formulation development for potential topical administration.

Bovine neonatal enteritis is a major cause of losses in cattle production, involving microbial and extra-microbial causative factors. Failure of passive transfer (FPT) plays a critical role in the development of this disease, and colostrum management and quality have a direct impact on FPT. The aim of this study was to investigate the effects of breed, parity and calf gender on colostrum IgG content and newborn calf immunity. Understanding the influence of these factors could be useful in implementing effective strategies to improve calf health. Breed emerged as a major factor affecting colostrum quality and calf immunity. IgG levels were compared in colostrum and newborn calf serum across dairy (Italian Friesian, Reggiana and Bianca Modenese) and cow-calf type (Piemontese and Limousine) breeds. Italian Friesian cattle showed significantly lower IgG levels in both their colostrum and newborn calf serum compared to the other breeds. Parity did not significantly affect overall colostrum quality or FPT prevalence. However, first-calf heifers had a lower prevalence of inadequate colostrum compared to multiparous cows, suggesting their colostrum is suitable for colostrum banks. With regard to gender, the analysis of IgG levels and FPT prevalence in Italian Friesian newborn calves revealed a significant sex disparity. Females exhibited higher IgG levels and lower FPT prevalence compared to males, suggesting potential management practices influencing these outcomes. In conclusion, results revealed significant differences in IgG concentration between colostrum and newborn calf serum samples across breed, parity, and calf gender. Newborn calves are particularly vulnerable and prone to enteritis. Poor colostrum management and breeding practices that prioritize high milk production can lead to lower IgG levels, further compromising calf immunity. While colostrum banks and cow vaccination offer potential solutions, limitations exist. Moreover, effective control requires close cooperation between farmers and veterinarians, which is often lacking.

A dairy herd must be considered an integrated production unit. From newborn calves to milking cows, animal health status is pivotal to get satisfactory economic results. The neonatal phase of calves is a period of life that needs extra care due to their vulnerability. Diarrhea is considered the main pathology affecting newborn calves. Conversely, respiratory disease is the main cause of losses after sixty days of life. The present study aimed at assessing the impact of neonatal diarrhea on growth, milk productivity and health status in a selected population of dairy cattle. A case-control study involving 300 calves from 5 large dairy herds located in the Po Valley (Italy) was carried out. All animals received lived-modified or inactivated, monovalent or combined vaccines for immunization to Bovine Herpesvirus 1 (BoHV-1), Bovine Viral Diarrhea Virus (BVDV) and Bovine Respiratory Syncytial Virus (BRSV). Particularly, most calves were administered with IBR marker and BRSV vaccines by intranasal route as priming immunization treatment. The enrolled animals were divided in two groups, each consisting of 150 calves. In the group A (cases) were included the animals experiencing severe neonatal diarrhea. Conversely, the group B (controls) included calves showing no clinical signs of neonatal enteritis. The animals were monitored in order to measure the body weight at birth, 6 and 15 months of age and milk production. Moreover, mortality rate and incidence of respiratory disease episodes during life were recorded. Animals of Group A showed a lower body weight at 6 and 15 months of age and a significant loss of milk production compared to those of the Group B. Moreover, incidence of respiratory disease and relapses were significantly higher in Group A. Results support the thesis that neonatal enteritis has a negative impact on weight gain during the grow period, milk production and is related to severe respiratory disease onset.

In recent years, due to the growing phenomenon of antimicrobial resistance, the search for alternative strategies to antibiotic treatments is increasing and a considerable interest for the use of medical honey in clinical practice has emerged. Honey has been used for the treatment of skin lesions, in both humans and animals. However, knowledge concerning the use of medical honey in non‑traditional companion animals is scarce. The aim of this study was to assess the antibacterial activity of a standardized medical honey (Revamil, BFactory) against bacterial strains isolated from skin lesions of non‑traditional companion animals. The minimum bactericidal concentration (MBC) of Revamil honey against seventeen clinical isolates and three reference strains was established.The medical honey showed antimicrobial activity against both Gram‑positive and Gram‑negative bacteria. Growth was inhibited for all the strains at concentrations of medical honey ranging from 10 to 40%. Pseudomonas oryzihabitans and Alcaligenes faecalis showed the lowest MBC (10%). The reference strain Staphylococcus aureus ATCC25923 showed a higher sensitivity to 20% honey compare to the corresponding clinical isolate (P = 0.001). The observed results suggest that Revamil could represent an effective therapeutic aid, useful for the reduction of antibiotic use, in case of pathological skin infections in non‑traditional companion animals.

Leptospirosis in cattle has important economic effects on the infected farms. Moreover, livestock farming is considered a major occupational risk factor for the transmission of Leptospira infection to humans. A survey was performed to determine the overall and within-herd seroprevalence and mapping of different Leptospira serovars in dairy cattle from farms located in some municipalities of the Colombian department of Boyacá. Nine hundred and fifty-nine animals, from 20 unvaccinated and one vaccinated herd, were included in the study. Anti-Leptospira serum antibodies were detected by the microscopic agglutination test (MAT). Only one herd was seronegative. Overall seroprevalence to at least one serovar of Leptospira was 24.1% for unvaccinated animals and 62.3% for animals from the vaccinated herd. A very high within-herd seroprevalence (>60%) was present in 20% of the unvaccinated herds. The presence in the vaccinated herd of 20/398 animals showing high titers, between 1000 and 4000, to at least one serovar of Leptospira suggest that some animals could have been infected. Moreover, due to the presence of seronegative animals, a failure of vaccination immunity or the presence of unvaccinated animals in the vaccinated herd cannot be excluded. In all farms, domestic animals other than cattle were present. Considering the farming practices occurring on dairy farms in the study area, higher hygienic standards and stricter biosecurity measures are suggested.

Antimicrobial resistance (AMR) is an increasing threat to human health and an important issue also in the natural environment. For this study, an ecopathological approach was applied to the monitoring of the antimicrobial resistance in the province of Parma, Northern Italy. Fourteen monitoring sites and seventy-four faecal samples from four species of wild micromammals (Apodemus sylvaticus, Microtus savii, Mus domesticus and Suncus etruscus) were collected. Samples were subjected to bacteriological examination and antimicrobial susceptibility testing. Antibiotics belonging to 13 different antibiotic classes were tested. Collected data showed a prevalence of multi-drug resistant (MDR) strains of 55.13% and significant differences in the prevalence of MDR strains among the different micromammal species, while sex, age and anthropization level did not significantly affected MDR strains prevalence. Moreover, a high prevalence of bacterial strains resistant to colistin (95%), gentamicin (87%) and amikacin (83%) was observed. To our knowledge, this is the first report on antibiotic resistance in wild micromammals in the province of Parma.

A cross-sectional study was carried out in Bardigiano horses in the Province of Parma, Northern Italy, to assess the seroprevalence of Leptospira spp. and to investigate risk factors associated with the infection. A representative sample of 134 horses from 43 farms was selected by stratified systematic randomization. Blood sera were examined by MAT for the presence of antibodies against seven Leptospira serovars. Ninety animals (67.2%; 95% Confidence Interval 63.2–71.1) and 41 farms (95.3%; 95% CI 92.2–98.5%) were found positive to at least one of the serovars. The most frequently detected reactions were against serovar Bratislava (41.8%), followed by Canicola (36.6%), Tarassovi (28.4%), Copenhageni (17.9%), Pomona (10.4%) and Hardjo (2.2%). None of the sera reacted against serovar Grippothyphosa. Forty-eight horses (53.3% of the seropositives) were positive for more than one serovar and 21 (15.7% of the seropositives) had serum titres ≥ 1000. Bratislava was the serovar providing the highest antibody titres. Prevalence was significantly higher between adult horses and in farms lacking rodent control (p = 0.006 and p = 0.025, respectively). No significant gender or housing-related difference in seroprevalence was found. The anamnestic data suggest that the infection in Bardigiano horses is subclinical in most of the cases. The high seroprevalence indicates that Bardigiano horses living in the investigated area are at high risk of exposure and infection by Leptospira spp.

Background Snakes are globally considered as pet animals, and millions of ophidians are bred in captivity. Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium that can act as an opportunistic pathogen of man and animals and is frequently present in the oral and cloacal microbiota of healthy ophidians. It can cause severe clinical diseases and often shows antibiotic resistance. The aim of this study was to evaluate the prevalence and antibiotic resistance profiles of P. aeruginosa isolated from the cloacal microbiota of a large population sample of healthy captive ophidians and to evaluate the statistical associations with farming conditions. Methods A total of 419 cloacal swabs were collected from snakes belonging to the Boidae (n = 45), Colubridae (n = 48) and Pythonidae (n = 326) families and inoculated onto complete culture media. Food, water and bedding samples were also analyzed. The antimicrobial susceptibility of P. aeruginosa isolates was evaluated through the Kirby-Bauer agar diffusion test. Statistical analyses were performed with the chi-square test. Results The prevalence of P. aeruginosa was 59.9%, and 35.5% of these strains were multidrug resistant (MDR). The prevalence of MDR P. aeruginosa was significantly higher in adult samples than in young samples, and widespread resistance to Cephalosporins, Polymyxins and Sulfonamides was observed. Statistically significant differences in the prevalence of P. aeruginosa were observed depending on the farm size and snake family. Feeding thawed prey was associated with a higher P. aeruginosa and MDR P. aeruginosa prevalence. Moreover, snakes fed home-raised prey had a significantly higher MDR P. aeruginosa prevalence than snakes fed commercially available feed. Less frequent terrarium cleaning was associated with a higher MDR P. aeruginosa prevalence. On the other hand, snake reproductive status was not significantly associated with P. aeruginosa or MDR P. aeruginosa prevalence. All food, water and bedding samples were negative for P. aeruginosa presence. Discussion The overall P. aeruginosa prevalence found in this study was lower than that found by other authors, but a high proportion of the isolates were MDR. This study highlighted the presence of constitutive (such as age and taxonomic family) and managerial (farm size, cleaning cycle frequency and food type) factors associated with P. aeruginosa and/or MDR P. aeruginosa prevalence. Good breeding management and proper antibiotic treatment of P. aeruginosa infections could help reduce the presence of P. aeruginosa and MDR P. aeruginosa in the gut microbiota of snakes and consequently reduce the risk to public health.

The bacterium Pseudomonas aeruginosa (PA) and the yeast Candida albicans (CA) are pathogens that cohabit the mucosa of the respiratory tracts of animals and humans. Their virulence is largely determined by chemical communication driven by quorum sensing systems (QS), and the cross perception of their quorum sensing molecules (QSM) can modulate the prevalence of one microorganism over the other. Aiming to investigate whether some of the protein components dissolved in the mucus layering the respiratory mucosa might interfere with virulence and cross-communication of these, and eventually other microorganisms, ligand binding assays were carried out to test the scavenging potential of the bovine and porcine forms of the Lipocalin odorant binding protein (OBP) for several QSMs (farnesol, and acylhomoserine lactones), and for pyocyanin, a toxin produced by PA. In addition, the direct antimicrobial activity of the OBPs was tested by time kill assay (TKA) against CA, PA and other bacteria and yeasts. The positivity of all the ligand binding assays and the antimicrobial activity determined for CA, and for some of the other microorganisms tested, let hypothesize that vertebrate OBPs might behave as humoral components of innate immunity, active against pathogenic bacteria and fungi. In addition, TKAs with mutants of bovine OBP with structural properties different from those of the native form, and with OBP forms tagged with histidines at the amino terminal, provided information about the mechanisms responsible of their antimicrobial activity and suggested possible applications of the OBPs as alternative or co-adjuvants to antibiotic therapeutic treatments.

Naja atra subsp. atra cardiotoxin 1 (CTX-1), produced by Chinese cobra snakes, belonging to Elapidae family, is included in the three-finger toxin family and exerts high cytotoxicity and antimicrobial activity too. Using as template mainly the tip and the subsequent β-strand of the first "finger" of this toxin, different sequences of 20 amino acids linear peptides have been designed in order to avoid toxic effects but to maintain or even strengthen the partial antimicrobial activity already seen for the complete toxin. As a result, the sequence NCP-0 (Naja Cardiotoxin Peptide-0) was designed as ancestor and subsequently 4 other variant sequences of NCP-0 were developed. These synthesized variant sequences have shown microbicidal activity towards a panel of reference and field strains of Gram-positive and Gram-negative bacteria. The sequence named NCP-3, and its variants NCP-3a and NCP-3b, have shown the best antimicrobial activity, together with low cytotoxicity against eukaryotic cells and low hemolytic activity. Bactericidal activity has been demonstrated by minimum bactericidal concentration (MBC) assay at values below 10 μg/ml for most of the tested bacterial strains. This potent antimicrobial activity was confirmed even for unicellular fungi Candida albicans, Candida glabrata and Malassezia pachydermatis (MBC 50-6.3 μg/ml), and against the fast-growing mycobacteria Mycobacterium smegmatis and Mycobacterium fortuitum. Moreover, NCP-3 has shown virucidal activity on Bovine Herpesvirus 1 (BoHV1) belonging to Herpesviridae family. The bactericidal activity is maintained even in a high salt concentration medium (125 and 250 mM NaCl) and phosphate buffer with 20% Mueller Hinton (MH) medium against E. coli, methicillin resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa reference strains. Considering these in vitro obtained data, the search for active sequences within proteins presenting an intrinsic microbicidal activity could provide a new way for discovering a large number of novel and promising antimicrobial peptides families.

Introduction - The control of bovine viral diarrhea (BVD) infection is based on three main pillars: implementation of bio-safety measures, test and cull of persistently infected animals (PI) and adoption of a vaccine protocol to prevent transplacental infection (fetal protection). Aim - The aim of this study is to verify, in field conditions, the efficacy of a combined approach that provides for detection and removal of PI animals and vaccination with a vaccine with the claim of fetal protection to BVDV. Materials and methods - The study lasted 9 years (November 2008-December 2017), was carried out in three farms located in the Province of Modena (Italy) and involved about 4,800 animals. Anamnestic data pointed out that in all the farms a BVD vaccination protocol was in place for at least 8 years (2001-2008) with both inactivated and modified-live vaccines. At the beginning of the study, all animals over 5 months of age were tested, in pool of 20 animals, for the detection of BVDV by RT-PCR. Subsequently, in the screening phase, PI research by RT-PCR was performed on all newborn calves. Moreover, BVDV detection in bulk milk was performed as well on a four-monthly basis. Regarding vaccination protocol, the animals were vaccinated with a modified-live vaccine (Mucosiffa (R)), namely heifers every six months and cows in the post-partum. Results and discussion - During the study, three PI animals were identified. These animals were born from non-PI cows vaccinated with an inactivated vaccine. During the period when the animals were vaccinated with the modified-live vaccine, no PI animals were detected. All the tests on bulk milk were negative for BVD antigen. Conclusion - The combined approach of vaccination with a modified-live vaccine, associated with test and cull of PI calves, allowed the control of BVD infection, as demonstrated by absence of new PI calves and BVDV circulation assessed by RT-PCR in bulk milk.

Introduction - At present, Mannheimia haemolytica (M.h.) is recognized to be the major bacterial pathogen involved in Bovine Respiratory Disease (BRD) outbreaks. Aim - The study is aimed at providing information on the prevalence of Mannheimia haemolytica, alone or in association with other pathogens, during Bovine Respiratory Disease (BRD) outbreaks involving dairy calves. Mannheimia haemolytica isolates were submitted to assessment of sensitivity to antibiotics widely used in buiatrics. Materials and methods - During 2012-2016, 185 acute respiratory disease outbreaks involving dairy cattle operations located in the Po Valley (Italy) were examined. From calves aged 10-180 days, 715 nasal swabs from animals showing acute respiratory signs and 66 respiratory tracts from died calves belonging to 39 BRD outbreaks were collected and submitted to laboratory investigations at detecting viral and bacterial respiratory pathogens. M. h. isolates were tested for their antimicrobial susceptibility by Kirby-Bauer method. Results and discussion - Results confirm that BRSV is the main viral pathogen involved in BRD. Laboratory investigations on nasal swabs and lung specimens collected from calves with acute clinical signs of disease allowed the isolation of 136 Mannheimia haemolytica strains with a prevalence of 17% and 24% for nasal swabs and lung specimens, respectively. A level of susceptibility > 75% to amoxicillin+clavulanic acid, ampicillin, ceftiofur, florfenicol, trimethoprim+sulfonamides was demonstrated. Conversely, a level of resistance > 50% to sulfadiazine and tylosin was detected. Our results are in accordance with other surveys carried out in Northern Italy. Conversely, disagreement with European reports regarding antibiotic sensitivity of M. h. was observed. European data regarding amoxillin-clavulanic acid, thirdgeneration cephalosporins, florfenicol, and fluoroquinolones showed lower resistance than those emerging from our findings. This phenomenon is caused by the extensive use in our cattle operations of antibiotics in general and of the above-mentioned antibiotic classes in particular. Conclusions - To limit the extensive use of antibiotics in BRD, preventive strategies should be carried out by using vaccines. For the control of M. h. - LKT pathogenic effect, monovalent and/or combo vaccines have long been available.

Antimicrobial resistance is a growing threat to public health. Pseudomonas aeruginosa is a relevant pathogen causing human and animal infections, frequently displaying high levels of resistance to commonly used antimicrobials. The increasing difficulty to develop new effective antibiotics have discouraged investment in this area and only a few new antibiotics are currently under development. An approach to overcome antibiotic resistance could be based on antimicrobial peptides since they offer advantages over currently used microbicides.

BACKGROUND:Pseudomonas aeruginosa (PA) may cause suppurative otitis externa with severe inflammation and ulceration in dogs. Multidrug resistance is commonly reported for this organism, creating a difficult therapeutic challenge.OBJECTIVE:The aim of this study was to evaluate the in vitro antimicrobial activity of a gel containing 0.5 μg/mL of antimicrobial peptide AMP2041, 0.07% chlorhexidine digluconate (CLX), 0.4% Tris and 0.1% EDTA on 30 clinical isolates of PA from canine otitis externa.MATERIALS AND METHODS:Antimicrobial activity was evaluated through minimal bactericidal concentration (MBC). Standardized bacterial suspensions were incubated with different concentrations of the gel at 37°C for 30 min and plated for colony forming unit (CFU) counts. Time-to-kill kinetics were evaluated with the undiluted product and at MBC for each PA strain at 30 s, 1, 5, 10, 15, 30 min, 24 and 48 h.RESULTS:The MBC was 1:64 for two of 30 strains, 1:128 for 15 of 30 strains and 1:256 for 13 of 30 strains. The geometric mean was 1:165, equivalent to a concentration of 0.003 μg/mL AMP2041 + 0.0004% CLX + 0.0024%Tris + 0.0006% EDTA. Time-to-kill assays with the undiluted product showed complete bactericidal effect within 30 s for all isolates, whereas at the MBC this effect was reached within 5 min for 20 of 30 isolates and within 30 min for all isolates. Bactericidal activity was maintained after 48 h for all isolates.CONCLUSION:This gel has shown rapid, complete and long-lasting activity against a panel of 30 PA isolates from cases of canine otitis externa.