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Biomedical subjects

P Moroni

Publications and source records attributed to P Moroni.

At least 19 recordsLinked to original sources
PubMed2006

Molecular typing of Staphylococcus aureus isolated from cows, goats and sheep with intramammary infections on the basis of gene polymorphisms and toxins genes.

We investigated 116 Staphylococcus aureus isolates from cows, goats and sheep with intramammary infections (IMI) in Italy to provide information about the spread of enterotoxigenic strains and to compare strains isolated from different ruminant species. The isolates were typed by restriction fragment length polymorphism (RFLP) analysis of the coagulase (coa) gene, by analysis of polymorphisms of the X region of protein A (spa) gene and by detection of genes encoding enterotoxins (sea, seb, sec, sed, see, seg, seh, sei, sej and sel). Seven different coa types and 12 different spa types were distinguished. On the basis of polymerase chain reaction-RFLP, 29 different coa subtypes were identified. Two different coa subtypes accounted for 49% and 67% of bovine and ovine isolates respectively. Only seven coa subtypes were observed in isolates from more than one host species and no coa subtype was present in isolates from all three ruminant species. Furthermore, 85 of the isolates (73%) harboured at least one enterotoxin gene (se) with a predominance of sea, sed and sej among isolates from bovine IMI, and sec and sel among isolates from caprine and ovine IMI. Comparing the S. aureus isolates on the basis of gene polymorphisms and presence of se genes, significant differences were found in distributions of genotypes among isolates from cows, goats and sheep.

Animals↗
PubMed2006

A structural equation model for describing relationships between somatic cell score and milk yield in dairy goats.

The relationship between milk yield and somatic cell score (log-transformed somatic cell count) in dairy goats may involve complex pathways with recursive or simultaneous effects. Structural equation models were fitted to longitudinal data on milk yield and on somatic cell scores. Data consisted of 4 repeated records of milk production and of somatic cell score from left and right halves of the udder in each of 47 dairy goats; infection status of each of the halves at each test day was also available. Results strongly suggest the existence of a within-half, first-order autoregressive process and of simultaneity of effects between somatic cell scores from the left and right halves of the udder. This indicates that the immune response to an infection is not restricted to the half of the udder in which the infection takes place and that it tends to propagate over time. The existence of a negative effect of somatic cell score on milk yield was also supported by the results; however, evidence in favor of an effect in the opposite direction, a dilution effect, was not strong.

Animals↗
PubMed2006

Technical note: Improved method for rapid DNA extraction of mastitis pathogens directly from milk.

Efficient control against bovine mastitis requires sensitive, rapid, and specific tests to detect and identify the main bacteria that cause heavy losses to the dairy industry. Molecular detection of pathogenic microorganisms is based on DNA amplification of the target pathogen. Therefore, efficient extraction of DNA from pathogenic bacteria is a major step. In this study, we aimed to develop a specific, sensitive, and rapid method to extract DNA directly from the main gram-positive bacteria known to cause bovine mastitis (Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, and Streptococcus uberis) found in milk samples. The DNA extraction method is based on the lysing and nuclease-inactivating properties of the chaotropic agent, guanidinium thiocyanate, together with the nucleic acid-binding properties of the silica particles. An efficient protocol consisting of 6 basic steps (3 of which were done twice) was developed and applied directly to milk samples. Absence of PCR inhibitors and DNA quality were evaluated by PCR amplification of the species-specific DNA sequences of the target bacteria. The level of sensitivity achieved in our experiments is applicable to milk sample analysis without sample enrichment.

Animals↗
PubMed2006

Relationships between somatic cell count and intramammary infection in buffaloes.

The objectives of this study were to evaluate the presence of intramammary infections (IMI) in dairy buffaloes and to examine the relationships among IMI, somatic cell counts (SCC), and milk production traits. Two farms in northern Italy were visited monthly for a complete milking season. Quarter-based milk samples were collected at each visit from 46 buffaloes. A total of 1,912 samples were assessed in this experiment. Samples were cultured for bacterial presence and were tested for SCC and percentages of milk protein and fat. In addition, daily milk yield was recorded from each buffalo. Prevalence of IMI was large; 63% of quarters were infected. No buffalo remained free from IMI throughout the course of the study. Coagulase-negative staphylococci were the most common pathogen (66% of positive samples). The SCC was distinctly greater in infected quarters; 100% of quarters with SCC >200,000 cell/mL had IMI, whereas 98% of quarters with SCC below this threshold were uninfected. The somatic cell scores (SCS) in these buffaloes were much lower than those commonly observed in dairy cattle. The mean SCS from quarters with IMI was only 2.93. The highest SCS was observed in quarters infected by streptococci. No drastic decrease in milk yield was observed among infected buffaloes relative to healthy contemporaries. The relatively low SCS and lack of a strong effect on milk yield provide evidence to discourage antibiotic treatment of buffaloes for subclinical IMI during lactation.

Animals↗
PubMed2006

Effect of cis-urocanic acid on bovine neutrophil generation of reactive oxygen species.

Neutrophils play a fundamental role in the host innate immune response during mastitis and other bacterial-mediated diseases of cattle. One of the critical mechanisms by which neutrophils contribute to host innate immune defenses is through their ability to phagocytose and kill bacteria. The ability of neutrophils to kill bacteria is mediated through the generation of reactive oxygen species (ROS). However, the extracellular release of ROS can be deleterious to the host because ROS induce tissue injury. Thus, in diseases such as mastitis that are accompanied by the influx of neutrophils, the generation of large quantities of ROS may result in significant injury to the mammary epithelium. cis-Urocanic acid (cis-UCA), which is formed from the UV photoisomerization of the trans isoform found naturally in human and animal skin, is an immunosuppressive molecule with anti-inflammatory properties. Little is known about the effect of cis-UCA on neutrophils, although one report demonstrated that it inhibits human neutrophil respiratory burst activity. However, the nature of this inhibition remains unknown. Because of the potential therapeutic use that a molecule such as cis-UCA may have in blocking excessive respiratory burst activity that may be deleterious to the host, the ability of cis-UCA to inhibit bovine neutrophil production of ROS was studied. Further, because neutrophil generation of ROS is necessary for optimal neutrophil bactericidal activity, a response which is critical for the host innate immune defense against infection, the effects of cis-UCA on bovine neutrophil phagocytosis and bacterial killing were assayed. cis-Urocanic acid dose-dependently inhibited the respiratory burst activity of bovine neutrophils as measured by luminol chemiluminescence. Subsequently, the effect of cis-UCA on the production of specific oxygen radicals was investigated using more selective assays. Using 2 distinct assays, we established that cis-UCA inhibited the generation of extracellular superoxide. In contrast, cis-UCA had no effect on the generation of intracellular levels of superoxide or other ROS. At concentrations that inhibited generation of extracellular superoxide, bovine neutrophil phagocytosis and bacterial activity remained intact. Together, these data suggest that cis-UCA inhibits the tissue-damaging generation of extracellular ROS while preserving neutrophil bactericidal activity.

Animals↗
PubMed2006

Short communication: antimicrobial drug susceptibility of Staphylococcus aureus from subclinical bovine mastitis in Italy.

The antimicrobial susceptibility of 68 Staphylococcus aureus isolates collected during 2004 from milk of cows affected by subclinical mastitis was examined. The antimicrobial agents tested were the beta-lactams, penicillin G, amoxicillin, ampicillin, cloxacillin, amoxicillin + clavulanate, cephalonium, and cefoperazone; and other drugs including lincomycin, oxytetracycline, doxycycline, and kanamycin. Minimum inhibitory concentrations recorded show that only certain beta-lactamase-resistant penicillins (specifically cloxacillin) or penicillin combinations (amoxicillin + clavulanate) were consistently effective against Staph. aureus, whereas the other beta-lactam derivatives and drugs from other pharmacological groups were either moderately effective or ineffective. Thus, beta-lactamase-resistant penicillins are to be considered the antimicrobial agents of choice for treatment of bovine mastitis resulting from infection by Staph. aureus.

Animals↗
PubMed2005

Risk factors for intramammary infections and relationship with somatic-cell counts in Italian dairy goats.

Routine examination of milk was performed on five herds of lactating goats in northern Italy as part of a milk quality-monitoring program in the year 2000. As part of the study, aseptic samples of foremilk were collected monthly from both half udders during the entire lactation for 305 goats, resulting in a total of 4571 samples. The samples were tested with cytological and bacteriological analyses to evaluate the relationship between mammary infections and somatic-cell count (SCC; Fossomatic (TM) method). Prevalence of intramammary infection (IMI) was 40.2% (n = 1837) of all udder-half samples examined. The most-prevalent mastitis agents were coagulase-negative Staphylococci (CNS), 80% (n = 1474 udder-half samples); within this group, Staphylococcus epidermidis was the most-prevalent species (38%). Other prevalence were Staphylococcus aureus 6% (n = 112 udder-half samples) and environmental pathogens 14% of infected udder-half samples (n = 251) with a diverse mixture of species, none of which had a frequency of > 4%. Enterococcus faecalis was the most-frequently isolated among this group. Neither Salmonella spp. nor Listeria monocytogenes were detected. The risk (sample level) of infection differed across herds, parities, and stage of lactation according to results from logistic multiple regression. Infection was more common among goats in third and fourth parities and during the later stages of lactation. Of the 2734 samples from uninfected udder halves, the mean log2 SCC was 3.9 cell/ml; of the 1837 bacteriological positive samples, the mean log2 SCC was 5.6 cell/ml. According to results from a linear mixed model, concentrations of somatic cells tended to increase with increasing age and days in milk and with the presence of bacteria. Infection with S. aureus was associated with the highest SCS.

Animals↗
PubMed2005

Subclinical mastitis and antimicrobial susceptibility of Staphylococcus caprae and Staphylococcus epidermidis isolated from two Italian goat herds.

A total of 156 goats from 2 commercial dairy goat farms were monitored for intramammary infections during an entire lactation. Most of the infections (80.7%) observed were due to coagulase-negative staphylococci (CNS) species. In herd 1, nearly all of the infections (96%) were due to CNS species, with Staphylococcus caprae (SCAP) being the most common specific pathogen observed, accounting for about 43% of the infections. In herd 2, the proportion of the infections due to CNS was 67% and Staphylococcus epidermidis (SEPI) was the most common pathogen (48% of infections) and SCAP was not present. Linear somatic cell scores (SCS) were greater in milk from infected udder halves, with an average difference of 0.78 SCS. The SCS for infected udder halves was greater than noninfected for all CNS species, although differences among species were observed. The ranking across CNS species was SCAP > other CNS > SEPI > no infection. However, infections by SEPI tended to be more persistent. Increased SCS was associated with a statistically significant decrease in milk yield, but no effect was observed for intramammary infections (IMI). Ninety-seven isolates of CNS (53 SCAP and 44 SEPI) were investigated for in vitro susceptibility to several antimicrobial agents. Benzylpenicillin was the most effective antimicrobial agent against SCAP and SEPI. A concentration of 0.05 microg/mL was sufficient to inhibit growth of 90% of SCAP colonies, and 0.10 microg/mL yielded a similar effectiveness for SEPI. Amoxicillin and the combination of amoxicillin and clavulanic acid were only slightly less effective. Tetracycline (62.5 microg/mL) and tilmicosin (500 microg/mL) were the least effective treatments for SEPI and SCAP, respectively.

Amoxicillin↗
PubMed2005

Application of a finite mixture model to somatic cell scores of Italian goats.

The objectives of this study were to apply a finite mixture model (FMM) to data for somatic cell count in goats and to compare the fit of the FMM with that of a standard linear mixed effects model. Bacteriological information was used to assess the ability of the model to classify records from healthy or infected goats. Data were 4518 observations of somatic cell score (SCS) and bacterial infection from both udder halves of 310 goats from 5 herds in Northern Italy. The records were from a complete production season, and were taken monthly from February to November 2000. Explanatory factors in both models included a 3-parameter regression on days in milk (DIM); fixed class effects of herd-test-day, parity group, and udder side (left or right); and random effects of goat and udder half within goat. In addition, the 2-component FMM included a fixed mean for the second component of the model (theoretically corresponding to infected udder halves), as well as an unknown probability of membership to a given putative infection status. A Bayesian statistical approach was used for the analysis with Gibbs sampling used to obtain draws from posterior distributions of parameters of interest. Two sampling chains of 200,000 cycles each were generated for each model. The FMM yielded a much lower estimate of residual variance than the standard model (1.28 vs. 3.02 SCS2), and a slightly higher estimate for the between-goat variance (1.79 vs. 1.48). The deviance information criterion (DIC) was used to compare the fit of the 2 models. The DIC was much lower for the FMM, indicating a better fit to the data. The FMM was able to classify correctly 60 and 48% of the healthy and infected observations, respectively. This was slightly higher than what would be expected from random classification, but not high enough for useful mastitis diagnosis. Nevertheless, increased precision of genetic evaluation is the goal of applying the FMM, rather than timely and accurate mastitis diagnosis. The results suggest that more research on FMM for SCS is merited and necessary for proper application.

Analysis of Variance↗
PubMed2005

Characterization of Staphylococcus aureus isolated from chronically infected dairy goats.

A herd of 88 Alpine goats in Northern Italy was monitored for a complete lactation. Milk samples were taken from each udder half during 8 monthly visits. Goats (n = 28) with > or =2 consecutive positive tests for Staphylococcus aureus in the same udder half were identified as chronically infected, and all of those had > or =4 positive tests of the 8 samples. Goats with no infections in either udder half during any visit were considered healthy (n = 26). Linear mixed models were used to examine the relationship between chronic infection by S. aureus and SCC and production traits. The bacteria isolated from one sample from each infected goat were genotyped on the basis of polymorphism in several genes and evaluated for the presence of genes encoding for enterotoxins. The bacteria isolated from each animal were also subject to a test for beta-lactamase production and to minimum inhibitory concentration tests for 11 antimicrobial agents. As expected, SCC (log2) was significantly higher in infected goats than in healthy goats (7.55 vs. 5.50). Also, mean log SCC from infected udder halves (8.02) was greater than that in uninfected udder halves from the same goats (6.44). No significant differences were observed in milk yield or for fat and protein percentages between infected and healthy goats. No genetic variability was observed among the bacteria isolated, suggesting that all were from the same strain, although isolates did vary in susceptibility to various antimicrobial agents. All S. aureus isolates were negative for the beta-lactamase production test. The most effective drugs when tested in vitro were benzylpenicillin, amoxicillin plus clavulanic acid, cloxacillin, and cephalosporins.

Animals↗
PubMed2001

Relationship between mammary gland infections and some milk immune parameters in Sardinian breed ewes.

Over the last few years an increased rate of intramammary infections caused by environmental and opportunistic pathogens has been observed in sheep farms. The presence of these microorganisms is mainly related to poor conditions of environmental hygiene and/or to decreased defenses of the mammary gland. The work we present here is a part of a project on the immune status of ewe mammary gland and its influence on mastitis development.In this paper, we have studied how intramammary infections caused by opportunistic pathogens reflect on immune parameters in ewe milk. Milk samples collected monthly before the morning milking, were screened for the presence of microorganisms and tested for somatic cell counts (SCC), polymorphonuclear neutrophil leukocytes (PMN), phagocytic activity, lysozyme content, and NAGase activity.Data showed that phagocytic activity was significantly higher in bacteriologically negative udders (156mV/1000 PMNs) than in infected udders (10mV/1000 PMNs).These results suggest that intramammary infection might be associated with a decrease of mammary gland immune status.

Journal Article↗
PubMed2000

Relationship between teat tissue immune defences and intramammary infections.

The teat is the main entrance for pathogens into the mammary gland. It also acts as a sensory, motor and primary defence organ. This latter function is important in preventing intramammary infections while efficiency in preventing new infections is determined by teat tissue integrity. Machine milking may evoke mechanical and circulatory impairment in teat tissues. These local metabolic disorders may decrease the efficiency of the local immune defence mechanisms. Teat tissue changes can be estimated by measuring teat thickness before and after milking. Experimental and field studies showed a high correlation between changes in thickness and infection risk. Teats with > 5% change in thickness have significantly increased teat duct colonisation rates and intramammary infection rates. The link between changes in teat thickness and infections should be found in changes in local immune defences and measurable changes in cytological and biochemical immune factors are expected. Indeed, the application of experimental milking conditions (i.e. no pulsation milking and positive pressure milking) showed to have a significant influence on some non specific immune factors in teat secretion. Positive pressure milking increases PMNs content and decreases macrophages content of teat secretion. Some enzymes such as NAGase and lysozyme were decreased by positive pressure milking, the concentration of the same enzymes were higher after no pulsation milking. A better knowledge on the interaction between the teat apex immune defense mechanisms and the machine milking process is necessary to reduce the new infection rate of the bovine mammary gland.

Animals↗
PubMed1999

Study on the relationship between milk immune factors and Staphylococcus aureus intramammary infections in dairy cows.

The distribution of Staphylococcus aureus within herds seems to be related to interactions among the shedding characteristics of the bacteria, their pathogenicity and mammary gland immune status. The aim of the present study was to investigate the relationships between selected mammary gland immune factors and intramammary infections associated with Staph. aureus. Overall, 70 cows from five commercial dairy herds were included in the study and quarter milk samples were assessed using bacteriological and cytological tests. We evaluated differential cell count, lysozyme concentration, N-acetyl-beta-glucosaminidase (NAGase) activity, cell viability and respiratory burst activity in randomly chosen quarter milk samples from each cow. Staph. aureus intramammary infection elicited different responses in the mammary gland immune defences investigated. Polymorphonuclear leucocytes (PMN) as a proportion of total somatic cells in milk, cell viability and NAGase activity were higher in infected quarters, while the proportions of macrophages and lymphocytes, respiratory burst activity and lysozyme levels were lower. Mean values differed among herds, but the differences were not significant. These changes were associated with Staph. aureus infection. The reduced respiratory burst activity together with the increase in the proportion of PMN suggests that both the number and activity of PMN could influence the susceptibility of the mammary gland to pathogens. Indeed, the logistic model adopted suggests that impairment of milk immune factors could be concurrent with the development of an infection.

Acetylglucosaminidase↗
PubMed1999

Galanin is released by adrenocorticotropin-secreting pituitary adenomas in vivo and in vitro.

Galanin, a brain-gut peptide, is also synthesized and released by the pituitary. In man, galanin-like immunoreactivity and galanin messenger RNA have been detected specifically in normal and tumoral corticotropes, but little is known about the production and release of galanin by the human pituitary. We evaluated galanin release by 5 ACTH-secreting pituitary adenomas in culture and plasma galanin concentrations in the inferior petrosal sinuses (IPSs) of 15 patients with Cushing's disease before and after CRH administration. For comparison, the galanin response to CRH was evaluated in 8 normal controls. Galanin secretion by pituitary tumor cultures ranged from 30-230 pmol/4 h. Incubation with CRH induced an increase in galanin concentrations (100 pM CRH: 151 +/- 32%; 1 nM CRH: 232 +/- 43%; 10 nM CRH: 246 +/- 35%; and 100 nM CRH: 270 +/- 44% unstimulated levels at 24 h, P < 0.05). The stimulatory effect of CRH seemed to be dose-dependent. Basal and CRH-stimulated ACTH and galanin concentrations also exhibited a strong positive correlation in single tumor cultures. At IPS sampling, mean basal plasma galanin concentrations in the dominant IPS were somewhat higher than those registered at the periphery (18.6 +/- 1.94 vs. 15.8 +/- 1.60 pmol/L, P = 0.05). Administration of CRH induced a modest but significant increase in galanin concentrations at all three sampling sites. No correlations were found between ACTH and galanin levels in the IPSs and at the periphery. Different from what was observed in patients with Cushing's disease, CRH did not modify plasma galanin concentrations in normal subjects. In conclusion, this study demonstrates that galanin is released by human tumoral corticotropes and responds to CRH. The role of locally produced galanin is, as yet, unknown but may possibly be that of a autocrine/paracrine modulator.

Adenoma↗
PubMed1999

Efficacy of a biological response modifier in preventing Staphylococcus aureus intramammary infections after calving.

A change in the epidemiology of mastitis in recent years has emphasized the role of the udder immune system in the pathogenesis of Staphylococcus aureus. Therefore, if the bovine or udder immune capability could be enhanced, susceptibility to Staph. aureus could be reduced and antibiotic efficacy could be increased. Immune system defense mechanisms could be enhanced by vaccination and by biological response modifiers. Within this latter group, a biological response modifier obtained from Parapox ovis that was attenuated over 200 tissue culture passages was recently developed and commercialized in some European countries. This study reports the results of a field trial on the efficacy of this biological response modifier in reducing Staph. aureus intramammary infection (IMI) after calving in primiparous and pluriparous cows. The trial included 106 cows sampled six times (55 cows from herd A and 51 from herd B) for a total of 2544 quarter milk samples. The analysis of IMI prevalence showed that 25.09% of samples were bacteriologically positive in the placebo group, and 23.17% of the positive samples were observed in the biological response modifier group. Staphylococcus aureus IMI had a frequency of 11.44% in the placebo group and 6.00% in the biological response modifier group. The dynamic of the hazards showed significantly lower rates in the biological response modifier group than in the placebo group (risk ratio = 0.47). Treatment with the parapox-containing biological response modifier showed significant reduction of Staph. aureus IMI around calving, and this reduction was attributed to an increase in immune defenses.

Adjuvants, Immunologic↗
PubMed1996

Field study on the relationship between teat thickness changes and intramammary infections.

The aim of this study was to describe the results of teat thickness measurement applied routinely in three commercial dairy herds and to evaluate the influence of machine-induced teat thickness changes on intramammary infection and the frequency of new infection. A total of 1018 fore milk samples and the same number of teat apex measurements have been evaluated. Overall, relative teat thickness changes were normally distributed (mean -0.16%, SD 10.15%), while a specific pattern could be observed within herds. Increases in teat thickness of > 5% were significantly associated with infection and new infection (odds ratio > 1), but the association was not significant when teat thickness decreased by more than 5%. When results were classified according to aetiology, analysis showed that coagulase-negative staphylococcal infections were significantly associated with both increases and decreases in teat thickness numerically greater than 5%.

Animals↗