Etiology Of Subclinical Mastitis Research Articles

Streptococcus Spp. Isolated Subclinical Mastitis and Its Effect on Public Health

The high protein content of milk makes it a crucial component of human nutrition. The mammary tissue of dairy cattle is seriously harmed by the severe disease known as mastitis. Mastitis is a widespread and economically significant infectious disease that affects dairy cows globally. One of the most frequent causes of subclinical mastitis in dairy cows and one of the most frequent indications for antibiotic therapy is Streptococcus spp. The purpose of the study was to investigate into the presence of Streptococcus spp. isolates in subclinical mastitis bovine milk. The presence of subclinical mastitis was investigated in 77 dairy animals. After the evaluation, 32 (41.5%) dairy animals showed positive results. Streptococcus spp. was detected in nine isolates (19.50%). As a result, it has been demonstrated that Streptococcus spp. still plays a significant role in the etiology of subclinical mastitis. This has the potential to present an important concern for public health.

O-099 Prevalence and aetiology of subclinical mastitis in sheep, as found in an extensive field investigation

O-099 Prevalence and aetiology of subclinical mastitis in sheep, as found in an extensive field investigation

Relationship between subclinical mastitis and reproduction in Lacaune sheep

The objective of this study was to determine how the occurrence and etiology of subclinical mastitis (SM) in the postpartum period was correlated with uterine involution (UI), return to estrus, and ovarian activity. Lacaune ewes (n = 87) were categorized based on the occurrence of one or more SM events diagnosed on days 5, 20, 35, and 50 after lambing. The animals diagnosed with SM (mastitis group, n = 49) were categorized according to the disease etiology into four groups (coagulase-negative Staphylococcus [CNS], Staphylococcus aureus, coliforms, and other gram-positive pathogens). The control group (n = 38) was ewes not diagnosed with SM at any of the evaluations. The group without pathogen isolation (WPI) consisted of SM-positive sheep according to the California Mastitis Test but without pathogen isolation by microbiological culture. Ultrasonographic examination of UI, characterized by uterine horn diameter ≤ 2 cm with no content in the uterine lumen, was evaluated on days 15, 30, and 45 after lambing. Ovarian activity was evaluated from the time of estrus detection every 12 h until ovulation. The number of corpora lutea and the total luteal area were determined 10 days after ovulation. Occurrence and etiology of SM were not correlated with ultrasonographic examination of UI, and at 45 days after lambing, all sheep had involuted uteri. Estrus detection began on the 20th day postpartum, and 57.47% (50/87) of the ewes exhibited estrus until the 60th day postpartum. The diameter of the largest follicle was smaller in ewes diagnosed with SM on the 50th day after lambing than in the control group (P < 0.05). The WPI group had a smaller diameter of the largest follicle (P < 0.001) than the control group and the CNS group. The number of follicles, the number of corpora lutea, and the total luteal area were not influenced by SM occurrence or etiology. The chance of exhibiting estrus within 60 days was higher in the group affected by mastitis than in the control group. Furthermore, twin-bearing ewes and ewes with viable lambs were less likely to express estrus.

Occurrence and aetiology of subclinical mastitis in water buffalo in Bangladesh.

Subclinical mastitis (SCM) in water buffalo is a production disease associated with decreased milk yield and impaired milk quality and safety. Water buffalo is an important livestock species in Bangladesh, but information about the occurrence and aetiology of SCM in this species is scarce. A cross-sectional study was conducted as part of the Udder Health Bangladesh Programme to (i) determine the occurrence of SCM and bulk milk somatic cell count (SCC) in water buffalo in Bangladesh, (ii) identify pathogens causing SCM and (iii) evaluate penicillin resistance in isolated staphylococci strains. Sixteen buffalo farms in the Bagerhat and Noakhali regions of Bangladesh were selected for study and a bulk milk sample was collected from each farm. In addition, 299 udder quarter milk samples were collected from 76 animals. The bulk milk samples were assessed by direct SCC and the quarter milk samples by California mastitis test (CMT). The occurrence of SCM calculated at quarter and animal level was 42.5 and 81.6%, respectively. Milk samples from 108 CMT-positive quarters in 48 animals and 38 randomly selected CMT-negative quarters in 24 animals were investigated using bacteriological culture. Estimated mean bulk milk SCC was 195 000 cells/ml milk (range 47 000- 587 000 cells/ml milk). On culture, estimated quarter-level intramammary infection (IMI) was 40.4%. The identity of isolated bacteria was confirmed by MALDI-TOF mass spectrometry. Non-aureus staphylococci (NAS) were the most common pathogens (24.7%) and, among 36 NAS tested, 36.1% were resistant to penicillin. Thus there was high occurrence of SCM on the study farms, with relatively high penicillin resistance in NAS. Further studies are needed to identify underlying risk factors and develop an udder health control strategy for water buffalo in Bangladesh.

Proteomics characterization of Staphylococcus spp. from goat mastitis and phenogeno-typical assessment of resistance to beta-lactamics

ABSTRACT: Mastitis occupies a prominent place among the diseases that affect dairy herds due to economic problems and public health. Staphylococcus spp. are infectious agents more involved in the etiology of caprine mastites, especially coagulase-negative Staphylococcus. Nineteen isolates of Staphylococcus spp. were obtained from subclinical caprine mastitis. All isolates were characterized by MALDI-TOF MS, being 47.36% (9/19) identified for S. epidermidis, 15.78% (3/19) for S. warneri, 10.52% (2/19) for S. aureus and S. caprae and 5.26% (1/19) for S. lugdunensis, S. simulans, and S. cohnii. All isolates characterized by MALDI-TOF were subjected a to polymerase chain reaction (PCR) for the 16S rRNA gene of Staphylococcus spp. to confirm the gender. After determining the species, tests for phenotypic detection of resistance to beta-lactams were carried out simple disk diffusion oxacillin, cefoxitin, penicillin G and amoxicillin + clavulanic acid, agar “screen” oxacillin and microdilution (MIC) cefoxitin. The disk diffusion test showed a strength of 58% (11/19) for penicillin G, 26.31% (5/19) for cefoxitin and 26.31% (5/19) for oxacillin. All strains were susceptible to amoxicillin + clavulanic acid and agar “screen” oxacillin. In the MIC, 63.15% (12/19) of the samples were cefoxitin resistant (MIC &gt;4.0μg/ml). Then isolates were subjected to detection of the mecA resistance genes and regulators (mecl and mecRI), mecC and blaZ. Two samples of Staphylococcus epidermidis had the mecA gene. All isolates were negative for the mecA gene variant, mecl, mecRI, mecC and blaZ. These findings reinforce the importance of this group of microorganisms in the etiology of subclinical mastitis in goats and open perspectives for future research to investigate the epidemiology of the disease.

The Prevalence and Etiology of Subclinical Mastitis in Sheep and Goats

From September 2016 to August 2017, four hundred and twenty four milk samples were collected from mammary halves of 212 apparently healthy lactating animals (108 ewes and 104 does) from small private flocks in different localities at Sharkia Governorate. All samples were investigated by California mastitis test (CMT) and bacteriological examination to determine prevalence and etiology of subclinical mastitis (SCM) in sheep and goats and to estimate the mean somatic cell count (SCC) of infected milk samples with different pathogens. The prevalence rates of SCM using CMT were 44 (40.7%) in ewes [59 milk samples, (27.3%)] and 50 (48.1%) in does [62 milk samples, (29.8%)]. Furthermore, out of ewes’ and does’ milk samples examined by bacteriological culture 54 (25.0%) and 56 (26.9%) samples were bacteriologically positive, respectively. The isolated bacterial causing SCM in ewes’ milk samples were E. coli (44.4%), S. aureus (38.9%), Streptococcus spp. (27.8%), coagulase negative Staphylococci (26.0%), Citrobacter spp. (3.7%) and Enterobacter spp. (1.9%). The identified isolates from does’ milk samples were S. aureus (46.4%), E. coli (26.8%), Streptococcus spp. (25.0%), coagulase negative Staphylococci (19.6%), Citrobacter spp. (5.4%) and Enterobacter spp. (3.6%). The geometric mean of SCC of milk samples harbored major pathogens was significantly (P < 0.05) higher than those harbored minor pathogens. Polymerase Chain Reaction (PCR) was applied on a total of 26 isolates from the most recovered species associated with mastitic milk samples of ewes and does. Suspected S. aureus, E. coli, Strep. agalactiae, Strep. dysagalactiae, and Strep. uberis isolates showed characteristic bands at 270 bp, 366 bp, 487 bp, 279 bp, and 723 bp which were specific for the used genes, respectively. In conclusion: a great attention should be directed to the early diagnosis of SCM in ewes and does.

Investigation On The Etiology Of Subclinical Mastitis In Jersey And Hybrid Jersey Dairy Cows

Abstract The aim of this study was to investigate the etiology of subclinical mastitis (SCM) in dairy Jersey cows with the use of bacteriological and molecular identification methods. In the study 121 Jersey and 78 hybrid Jersey cows with SCM were observed in the Samsun district of Turkey. A total of 411 California mastitis test (CMT) positive milk samples from these animals were examined bacteriologically. The prevalence of subclinical mastitis was 54.75% and 67.2% in Jerseys and hybrids, respectively. On bacteriological examination, a total of 92 strains were isolated from 411 milk samples. The most prevalent bacteria were Staphylococcus spp. (69.56%). Among them 24 isolates were Staphylococcus aureus (26.08%) the other isolates were Streptococcus dysgalactiae (23.91%), Enterococcus spp. (3.26%) and Streptococcus agalactiae (3.26%). All strains were identified with bacteriological culture methods, as well as by Polymerase Chain Reaction (PCR). Gram-negative bacteria were not isolated. In conclusion, the etiology of SCM in full blood and hybrid Jersey dairy cows in Samsun and the prevalence of bacteria were determined. The relatively high prevalence of SCM indicates the potential need for the consideration of some factors contributing to the formation of mastitis (e.g. management) as well as bacterial agents. The present study and further studies may be useful to develop mastitis vaccines by means of providing true vaccine strain sources.

Prevalence and etiology of subclinical mastitis in dairy ewes in two seasons in Semnan province, Iran.

Twenty-one dairy ewe flocks selected by stratified random sampling were subjected to study the prevalence and etiology of subclinical intramammary infections and to assess the influence of parity on the prevalence of intramammary infections. Also, spontaneous cure rates were determined over study period. A total of 1192 milk samples were collected at 2 weeks after lambing until tenth-week postpartum. All flocks had hand milking; those which were classified by bacterial culture and California Mastitis Test (CMT) as positive were deemed to have glands with subclinical mastitis (SCM). Of 1192 halves examined, 791 samples were collected during spring and 401 samples were collected during summer. Prevalence rate of SCM in spring was 14.7 %; and spontaneous cure that occurred in this season was 88.8 %; coagulase-negative staphylococci (CNS) were the most common isolates (66.6 %). Samples collected in spring showed higher prevalence rate of SCM than summer samples. This rate was 8.9 % in summer. Spontaneous cure rate in this season was 69.4 %, and Staphylococcus aureus (72.2 %) was the most common isolates. SCM was seen at significantly lower rates in left half than in right one (p < 0.05). Multiparous ewes had significantly higher (p < 0.05) SCM prevalence rates than primiparous ewes. The incidence of clinical mastitis (defined as number of clinical cases per 100 ewe-months) was 0.21 and 0.74 in spring and summer, respectively. The isolates from clinical cases in spring were fungi and, from summer, were S. aureus. Also, S. aureus SCM cases were not significantly severe than other SCM cases. In conclusion, multiparous ewes were most at risk, and severity of infection was higher in summer.

Prevalence and Etiology of Subclinical Mastitis among Buffaloes (Bubalus bubalus) in Namakkal, India

Milk samples from 206 apparently healthy buffaloes of marginal farmers maintained under the prevailing field conditions were screened for Subclinical Mastitis (SCM) to determine its prevalence and etiology by White Side Test (WST), California Mastitis Test (CMT), Somatic Cell Count (SCC) and Bacteriological examination. 26.20% of animals were positive for SCM in SCC and bacteriological examination. Prevalence in graded Murrah buffaloes were found to be higher compared to graded Surti and Non-descript breeds. The prevalence of SCM was highest in above 6th stage of lactation. Single quarter infection (51.85%) was more common compared to multiple quarter infection. Hind (83.34%) and left side (57.41%) quarters were more prone to SCM. The indirect tests such as WST and CMT were found to be closely agreement with SCC and bacteriological examination. Due to their efficacious, easy to perform and interpret, these tests can effectively be employed to detect SCM under field conditions. Somatic cell count of = 3,00,000/mL of milk was regarded as the upper limit for normal buffaloes. The SCC of = 3,00,000/mL of milk with positive bacterial growth were used to diagnose SCM in the present study. Staphylococcus sp. 25 (46.30%) was the most common pathogens isolated from SCM followed by Streptococcus sp. 11 (20.37%) and E. coli 06 (11.11%) of the 54 bacterial isolates. Monobacterial and mixed bacterial infections were observed in 47 (87.04%) and 7 (12.96%) cases respectively.

Prevalence and Etiology of Subclinical Mastitis in Small Ruminants of Tigray Regional State, North Ethiopia

A study was conducted at Kafta Humera and Tanqua Abergelle Districts from April to June, 2011 to assess the prevalence of subclinical mastitis in lactating small ruminants and identify bacterial causative agents. A total of 390 lactating animals comprising 255 goats and 135 sheep were randomly selected from population and screened for evidence of subclinical mastitis. The overall prevalence of subclinical mastitis was found to be 18.03% (46/255) and 28.14% (38/135) in goats and sheep, respectively. California mastitis test (CMT) positive milk samples were subjected to bacteriological examination and the following bacteria were isolated; coagulase negative Staphylococcus (44.7%), Staphylococcus aureus (27.7%), Escherchia coli (17.0%) and streptococci (10.63%). Risk factors; species (p = 0.021), study site (p < 0.001), sheep breed (p = 0.018) and goat breed (p = 0.009) showed statistically significant association with the occurrence of subclinical mastitis in small dairy ruminants. However, there was no statistically significant association between risk factors such as Age (p = 0.779), parity (p = 0.201) and stage of lactation (p = 0.952). Therefore, it can be concluded that mastitis is a significant disease in small ruminants that affects their productivity and measures need to be taken to control the disease.

Prevalence and aetiology of subclinical mastitis in goats

The study was conducted in 2006 on 20 French alpine goat farms in Croatia. Milk samples were taken from each udder half, for the mastitis test and the bacteriological test, 2120 samples in total. Subclinical mastitis was diagnosed in 211 out of 1060 goats, or in 20% of the studied population. Mastitis of one udder half was diagnosed in 84% of the affected population, while mastitis of both udder halves was diagnosed in 16% of the affected goats. A positive mastitis test reaction was identified in 605 samples (28%), and the pathogenic bacterium was isolated from 244 of these samples (36%). From 22 samples (1.5%) which were negative to mastitis test, pathogenic bacteria, namely S. aureus (21 samples) and Streptococcus D (1 sample), were isolated. Staphylococcus aureus was isolated from 72% mastitis test positive samples, coagulase-negative staphylococci in 16%, other bacteria were isolated from a smaller number of samples: Streptococcus D (6%), Bacillus spp. (2%), and E. coli (2%). The results of the study lead to the conclusion that the subclinical mastitis in goats has a prevalence of 20% on average which increases with higher lactation number. Staphylococcus aureus is the primary causative agent of the inflammations.

Period prevalence and etiology of subclinical mastitis in Awassi sheep in southern Jordan

To investigate the period prevalence, etiology and some epidemiological features of subclinical mastitis in Awassi ewes from the southern part of Jordan, milk samples from 318 lactating ewes were aseptically collected for bacterial and somatic cell counts (SCC) tests. Milk samples were collected at monthly intervals. The period prevalence of subclinical mastitis was 18.3% and the prevalence within each flock remained relatively constant throughout the study period. A significant association ( P<0.001) was observed between the occurrence of subclinical mastitis and the age of ewe. Presence of teat lesions has no impact on the prevalence of subclinical mastitis. The prevalent bacterial species isolated from mammary glands with subclinical mastitis were Staphylococcus aureus (39%), Streptococci (25%), Escherichia coli (19.6%) and coagulase-negative Staphylococci (17.9%). Coagulase-negative Staphylococci were the most prevailing isolates from samples that showed negative SCC results.

Prevalence and etiology of subclinical mastitis in intensively managed flocks and related changes in the yield and quality of ewe milk

A total of 1140 milk samples from 380 randomly selected Comisana ewes, in parities 1–6, were collected aseptically during early-, mid- and late-lactation from five intensively managed flocks located in the Apulia region, southern Italy. All flocks were housed on straw litter in prefabricated buildings, were given hay and pelletted concentrates and were milked twice daily using pipeline milking machines. Individual milk samples were analyzed for composition, renneting parameters and somatic cell count (SCC), and cultured for mastitis related pathogens. No cases of clinical mastitis were detected. Mean incidence rates were 8.4, 5 and 4.1%, respectively, for infectious (bacteriologically positive milk samples with >10 6 somatic cells/ml), latent (bacteriologically positive milk samples with <3×10 5 somatic cells/ml) and non-specific subclinical mastitis (bacteriologically negative milk samples with >10 6 somatic cells/ml). Environmental pathogens, primarily E. coli, were largely predominant in the milk from infected ewes and markedly increased with the advancement of lactation. Reduction in ewe milk yield and deterioration of milk quality and renneting ability were more marked in infectious and non-specific than in latent mastitis cases, whereas various kinds of pathogens had a similar impact on milk yield and composition. The low incidence of contagious pathogens suggests that, in intensive production systems, ewe udder health may benefit from more efficient control of sanitation of milking practices and equipment. The high prevalence of environmental and opportunistic micro-organisms also indicates that poor ambient hygiene and exposure of ewes to environmental and management stressors must be regarded as the main risk factors for udder infections .

Prevalence and aetiology of subclinical mastitis in dairy ewes of the Madrid region

A bacteriological survey for studying the prevalence and aetiology of subclinical mastitis was carried out in 22 dairy sheep flocks of the Madrid region. A total of 1128 milk samples were collected from 564 ewes. 17 Manchega flocks (5 flocks had mechanical milking and 12 flocks had hand milking) and 5 Assaf flocks (all had mechanical milking) were included in the study. Prevalence of subclinical mastitis in the different flocks ranged from 4.5–67% of the glands and 9–83% of the animals, with an average of 21 and 34.%, respectively. Prevalence of subclinical mastitis in Manchega flocks with mechanical milking was lower than those with hand milking ( P<0.05). Assaf flocks had higher prevalence rates than Manchega flocks with mechanical milking ( P<0.05). Increase of subclinical mastitis as lactation proceeded was observed only in Assaf ewes. Prevalence of subclinical mastitis was lower in primiparous Manchega and Assaf ewes than those which had two of more lactations. CMT score 1(+), with the best combination of sensitivity and specificity values, can be recommended as a threshold value for detecting subclinical mastits. Coagulase-negative staphylococci were the most prevalent bacteria, representing 68% of the isolates. Staphylococcus epidermidis (40%), was the most prevalent species followed by Staphylococcus haemolyticus, Staphylococcus simulans and Staphylococcus xylosus. Corynebacterium was the second bacterial group in importance according with the distribution among flocks, being isolated from 41% of the flocks and representing 10% of the isolates, which suggests for these bacteria, a clinical significance higher than that traditionally considered as responsible for subclinical mastitis in sheep. Subclinical mastitis seems to be, as deduced from the high prevalence observed in this study, an important health problem for milking sheep flocks in the Madrid region.

Prevalence and aetiology of non-clinical intramammary infection in Murciano-Granadina goats

Ten herds of Murciano-Granadina goats were examined to determine prevalence and aetiology of subclinical mastitis in Murcia (Spain). In the 369 milk samples analysed from 188 animals, intramammary infection was present in 18% of the glands and 30% of the goats. Prevalence of infection in the different herds ranged from 7% to 34% of the glands and 17% to 44% of the goats. Sixty-nine bacterial isolates were found, comprising staphylococci (71%), corynebacteria (12%), mycoplasmas (9%), enterobacteria (3%), pasteurellas (3%), streptococci (1%) and yeast (1%). Among the 49 staphylococcus isolates, Staphylococcus caprae (22%), Staphylococcus epidermidis (20%) and Staphylococcus chromogenes (12%) were the most frequent of the 12 species identified. Staphylococcus aureus (6%) had a low prevalence, and only one isolate was coagulase positive. S. caprae showed the highest prevalence among the herds, and mycoplasmas and S. epidermidis were most responsible for bilateral infections (60% of those detected).

Prevalence and aetiology of subclinical mastitis in ewes of Southern Greece

In a field investigation of ovine mastitis in eight flocks in Southern Greece, a population of 760 dairy ewes was monitored during lactation. The prevalence of subclinical mastitis was 4.5% on the 1st sampling (at weaning of lambs), 11.2% on the 2nd sampling (2 to 3 weeks later) and 16.9% on the 3rd sampling (6 to 8 weeks after the second sampling). Although the prevalence of subclinical mastitis increased as the lactation period advanced, the risk rate of the disease decreased. Coagulase-negative staphylococci ( Staphylococcus epidermidis, Staph. simulans, Staph. chromogenes, Staph. xylosus) were the main causal agents of the disease, but Staph. aureus, streptococci, Bacillus spp., Escherichia coli, Pasteurella haemolytica and Actinomyces pyogenes were also isolated from cases of subclinical mastitis. Of the 1084 milk samples collected, somatic cell counts more than 1.0 × 10 6 cells/ml were found in 97 (8.9%); 64 were bacteriologically positive, but 33 bacteriologically negative.