BackgroundStaphylococcal mastitis is a common disease of small ruminants causing major economic losses. The problem is particularly significant in the rural areas of the Mediterranean region, where almost two thirds of the global sheep and a quarter of the global goat milk are produced. This study aimed to gain insight into the genotypes, antimicrobial resistance (AMR) profiles and virulence factors of Staphylococcus aureus isolated from clinical mastitis in small ruminants’ farms from different 25 dairy herds in six different provinces in Sardinia, Italy between December 2021 and May 2022.MethodsThirty- two S. aureus were phenotypically identified and confirmed by real-time PCR. Whole-genome sequencing (WGS) was conducted and the sequence data were analyzed to reveal the genetic diversity, AMR markers and virulence genes to draw a conclusion for a current situation of small ruminants’ clinical mastitis in dairy herds in the region and the potential public health risk. Furthermore, the phylogenetic relations between S. aureus strains within one farm and from various farms was analyzed.ResultsAll isolates proved to be phenotypically Methicillin-susceptible S. aureus (MSSA), and none of them harbored mecA/C genes. The antimicrobial resistance against Tetracycline and Erythromycin were 15.62% and 3.12%, respectively. The isolates were assigned to ten sequence types in addition to five different clonal complexes using multilocus sequence typing (MLST). Sequence types ST133 (46.9%) and ST700 (21.9%) were the dominant types, and the majority of isolates were assigned to either CC133 (56.25%) or CC130 (34.4%). Twelve different spa-types were identified among isolates, while six isolates were not assigned to known spa-types. The dominant spa-type was t1773 (18.75%) which is known to be associated with CC130. All Tetracycline-resistant isolates harbored tet genes. The only Erythromycin-resistant isolate carried the erm(T) gene. The leucocidin genes lukF-PV (P83)/lukM were detected in 20 isolates (62.5%), while one isolate (ST522) carried a chimeric leukocidin.ConclusionIn conclusion, this study showed a considerable genetic diversity of S. aureus isolated from sheep and goat mastitis in Sardinia, Italy, and the prominent sensitivity to most of antimicrobial agents relevant for mastitis treatment. These findings inform about the local mastitis control strategies and highlight a low immediate public health risk from antimicrobial resistance in this setting.

Staphylococcus aureus and coagulase-negative staphylococci (CNS) are the main causative agents of mastitis in sheep. Their ability to form biofilms in vivo is considered an important virulence factor underlying mastitis outbreaks refractory to antibiotic treatments. Furthermore, pre- and postdipping immersion during milking in iodine substances could determine the presence of residues in milk and therefore represent a health risk factor for consumers. The aim of this study was to evaluate the antibacterial and biofilm inhibitory activity of Thymus vulgaris L. essential oil (TEO) against staphylococci strains isolated from ovine clinical mastitis. In particular, 3 reference strains (S. aureus 25923 and 11623 and S. epidermidis 12228) and 12 clinical isolates (6 S. aureus and 6 CNS) were used. TEO solutions, from a concentration of 1% (v/v) to 1.25% (v/v), corresponding to 9.28-2.32 mg/mL, were obtained after solubilization in 10% dimethyl sulfoxide (DMSO) and used to evaluate the bacterial time-kill compared to that of an iodine-based solution. Antibacterial efficacy was then assessed by the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), while biofilm inhibition was assessed by minimum biofilm inhibitory concentration (MBIC) using a spectrophotometer at a wavelength of 570 nm. Additionally, biofilm-associated genes (icaA and icaD) were evaluated in all tested strains by PCR. The tested TEO concentrations were able to significantly and prominently reduce bacterial growth compared to controls, as demonstrated by bacterial time-kills. The MIC value was obtained at a concentration of 0.50% (v/v) for a single coagulation-positive isolate (S. aureus (f)) and at a concentration of 0.25% (v/v) for all other isolates. TEO showed effective bactericidal action with a 99.9% reduction in CFU/mL of all isolates in the MBC test at a concentration of 0.25% (v/v) for most of the tested strains. Furthermore, a marked inhibition in biofilm formation at all tested concentrations was observed, with MBIC value of 0.25%. All S. aureus tested were biofilm-producing strains and positive for icaA and icaD genes, while two CNS biofilm-producing strains were negative for both genes. These preliminary results suggest that TEO could be a promising alternative as an udder disinfectant during milking practices. Although in vivo studies are needed to confirm the efficacy and safety of TEO as an adjuvant in the prevention and treatment of udder infections, TEO could help counteract the emergence of antimicrobial resistance and reduce the potential risk of iodine residues in milk.

The role of non-aureus Staphylococcus in small ruminant mastitis: A systemic review on etiological agents, risk factors, virulence determinants, and novel treatments

This paper outlines the results of researching the incidence of mastitis in small ruminants in the Republic of Croatia over a six-year period (2017 to 2022). During this period, microbiological testing was performed on 801 samples of udder secretions from small ruminants in 13 counties and the city of Zagreb, with 178 samples (22.2%) testing positive for mastitis pathogens. Of the total 609 udder secretion samples from goats, mastitis agents were isolated from 150 samples (24.6%), while the 192 udder secretion samples from sheep revealed 28 (14.6%) contained mastitis agents. The highest prevalence of mastitis pathogens in goat udder secretions was found in 2018 (31.8%), and in sheep in 2020 (32.9%). Microbiological testing identified 16 species and genera of bacteria. The most common species were Staphylococcus aureus, isolated from 96 (53.9%) samples, Staphylococcusspp. (46 samples; 25.8%), Streptococcus spp. (7; 3.9%), Klebsiella spp. and Corynebacterium spp. (each 5; 2.8%), Escherichia coli (4; 2.2%), Streptococcus uberis and Proteus spp. (each 3; 1.7%), and Pseudomonas spp. (2; 1.1%). Other species and genera, such as Streptococcus agalactiae, Streptococcus dysgalactiae, Pasteurella spp., Mannheimia haemolytica, Enterococcus spp., Enterobacter and Serratia spp. were isolated sporadically, each from one sample. The isolated bacterial cultures were tested for sensitivity to antimicrobials using the disc-diffusion method to amoxicillin with clavulanic acid, ampicillin, cefaperazone, enrofloxacin, kanamycin, cloxacillin, lincomycin, neomycin, novobiocin, penicillin, streptomycin, sulfamethoxazole withtrimethoprim, and tetracycline. Sensitivity of the isolated agents to the antimicrobials was most pronounced towards cefoperazone and enrofloxacin, regardless of the species or genera of the isolated mastitis agent. The odds of isolating a mastitis agent from goat udder secretions was 1.61 times higher than for sheep (P<0.05). This study confirmed that the occurrenceof mastitis in small ruminants in Croatia is comparable to incidences reported in other Mediterranean countries.

IntroductionStaphylococci are still a challenge in veterinary medicine, as they are one of the aetiological factors causing clinical and subclinical mastitis in small ruminants. The aim of the study was to analyse the occurrence of staphylococci in milk obtained from Świniarka (SW) and Uhruska (UHR) sheep and to characterise their drug resistance and virulence.Material and MethodsIn total, 50 milk samples were collected from ewes seven days after parturition. Drug susceptibility analysis was performed based on Clinical and Laboratory Standards Institute standards and demonstration of the presence of resistance genes was attempted.ResultsStaphylococcus spp. strains were identified in 70% of the samples, and 57.2% of the strains were S. aureus. Most of the tested strains (88.6%) were resistant to at least one antimicrobial, and resistance to tetracycline and erythromycin was the dominant type in S. aureus strains. Coagulase-negative species (CoNS) exhibited resistance predominantly to penicillin, cefoxitin and tetracycline (86.6%, 73.3% and 46.6%, respectively).The presence of the mecC gene was detected in four cefoxitin resistant strains. In tetracycline- and chloramphenicol-resistant strains, phenotypic and genotypic resistance was statistically significantly more common among strains isolated from UHR than SW.ConclusionThe present study highlights the problem of potential subclinical mastitis caused by drug-resistant strains of S. aureus and other CoNS species in lambed ewes. However, the occurrence of virulence factors in these strains is very rare.

Epidemiological and Therapeutic Profile of Mastitis in Small Ruminants in the Labé Region (Guinea)

Mastitis in small ruminants presents significant challenges in veterinary medicine owing to its impact on animal welfare and productivity. This case study documents clinical mastitis in a four-year-old postpartum Ettawah crossbred ewe. During the physical examination, inflammation was noted in the right mammary gland. The ewe's condition deteriorated due to open sores, which developed because of the friction between the mammary gland skin and the floor while the ewe was recumbent. The lesion expanded, producing purulent exudate that eventually formed scabs. Discontinuing milking in the affected mammary gland adversely affects its health, as milk accumulation in the alveoli facilitates bacterial growth and proliferation. The treatment regimen included penicillin and sulpidon; however, the ewe's condition continued to decline, indicating ineffectiveness of the treatment.

Mastitis is an important disease of small ruminants (SR) that results in substantial morbidity, mortality, and economic losses from treatment or loss of product. There is currently little in­formation on SR mastitis pathogens or antimicrobial sensitivity in U.S. populations. This study 1) identifies breed, age, produc­tion use and stage of lactation of SR diagnosed with mastitis at a veterinary teaching hospital (VTH); 2) characterizes bacterial species and antimicrobial sensitivity in SR mastitis; and 3) clas­sifies SR mastitis into peracute, acute, subclinical and chronic, and correlates with bacterial isolates.

Staphylococci and streptococci are common causes of intramammary infection in small ruminants, and reliable species identification is crucial for understanding epidemiology and impact on animal health and welfare. We applied MALDI-TOF MS and gap PCR–RFLP to 204 non-aureus staphylococci (NAS) and mammaliicocci (NASM) and to 57 streptococci isolated from the milk of sheep and goats with mastitis. The top identified NAS was Staphylococcus epidermidis (28.9%) followed by Staph. chromogenes (27.9%), haemolyticus (15.7%), caprae, and simulans (6.4% each), according to both methods (agreement rate, AR, 100%). By MALDI-TOF MS, 13.2% were Staph. microti (2.9%), xylosus (2.0%), equorum, petrasii and warneri (1.5% each), Staph. sciuri (now Mammaliicoccus sciuri, 1.0%), arlettae, capitis, cohnii, lentus (now M. lentus), pseudintermedius, succinus (0.5% each), and 3 isolates (1.5%) were not identified. PCR–RFLP showed 100% AR for Staph. equorum, warneri, arlettae, capitis, and pseudintermedius, 50% for Staph. xylosus, and 0% for the remaining NASM. The top identified streptococcus was Streptococcus uberis (89.5%), followed by Strep. dysgalactiae and parauberis (3.5% each) and by Strep. gallolyticus (1.8%) according to both methods (AR 100%). Only one isolate was identified as a different species by MALDI-TOF MS and PCR–RFLP. In conclusion, MALDI-TOF MS and PCR–RFLP showed a high level of agreement in the identification of the most prevalent NAS and streptococci causing small ruminant mastitis. Therefore, gap PCR–RFLP can represent a good identification alternative when MALDI-TOF MS is not available. Nevertheless, some issues remain for Staph. haemolyticus, minor NAS species including Staph. microti, and species of the novel genus Mammaliicoccus.

Staphyloccoccus aureus is the major cause of mastitis in small ruminants in the Mediterranean farms causing severe losses to dairy industry. Antibiotic treatment has been the most common approach to control these infections. Aim of this study was to investigate antimicrobial resistance (AMR), virulence factors and biofilm-related genes of 84 Sicilian strains of S. aureus isolated from sheep and goats milk during two different periods δT1 (2006-2009) and δT2 (2013-2015). Kirby Bauer method and Polymerase Chain Reaction (PCR) were utilized to monitor AMR and related genes (mecA, tetK, tetM, ermA, ermC). Moreover, toxin genes (tsst-1, sea-see, seg-sej, and sep) and biofilm genes (bap, ica, sasC) were studied. Twenty-six isolates (30.9%) showed multidrug resistance. The two groups showed similar results with exception for higher values of resistance for tilmicosin and lower for sulfamethoxazole and vancomycin of the second group. MecA gene was detected in one isolate. Tetracycline resistance was higher than 20%, with an increase in δT2 group. Toxin genes were found in 5 isolates (5.9%), belonging of δT2 group, while 57 of isolates (67.8%) showed biofilm related genes. The high presence of multi-resistant isolates suggests the need of more responsible use of antibiotic therapy for the control of these infections.

Mastitis often reduces animal performance and productivity as well as farm profitability. The purpose of this article is to help small ruminant producers to identify, treat, control, and prevent mastitis in small ruminants. Written by Izabella Toledo and Justina Dacey, and published by the UF/IFAS Department of Animal Sciences, September 2021.

ABSTRACT Mastitis is an important infirmity that affects dairy goats and sheep flocks. Antimicrobials are widely used in mastitis therapy; however, the phenomenon of bacterial resistance has sparked interest in therapeutic alternatives, especially the research on essential oils from several plant species. Therefore, this study aimed to evaluate the antimicrobial activity of essential oils against pathogens of importance in caprine and ovine mastitis. The essential oils were obtained by hydrodistillation and the chemical composition was analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests were performed to evaluate the antimicrobial activity of the essential oils (EO) of four plants. Fifteen bacterial isolates, previously identified as Staphylococcus spp. and Staphylococcus aureus, were used. The following plant species were used against the 15 bacterial isolates: Lippia origanoides “alecrim pimenta,” Lippia alba “erva cidreira,” Cymbopogon citratus “capim-santo,” and Ocimum basilicum “manjericão.” The first three essential oils presented antimicrobial activity against 100% of the isolates (15/15), with MICs of 560 µg mL-1, 1,173 µg mL-1, and 1,280 µg mL-1, and MBCs of 613 µg mL-1, 1,226 µg mL-1, and 1,333 µg mL-1, respectively. Nevertheless, the essential oil of O. basilicum, which was also tested, exerted no activity against any of the isolates. Carvacrol, citral, geraniol, and estragole were some of the major compounds found. These results can aid other studies that aim to use these essential oils as potential products for subsequent use in the treatment of mastitis in small ruminants.

Simple SummaryThe health and functionality of the mammary gland are important factors in animal welfare and milk production. Inflammation of the udder is associated with reduced milk yield and dairy product quality. Even though mastitis is usually caused by bacterial, fungal, or algae infections, some studies have suggested that infection with small ruminant lentivirus (SRLV), causing caprine arthritis-encephalitis (CAE), can also cause mastitis in small ruminants. Its pathophysiology is not, however, fully understood. Therefore, the aim of this study was to determine whether seropositive goats were more susceptible to bacterial infections of the udder than uninfected goats. A higher prevalence of pathogenic bacteria was identified only in seropositive goats in the 5th or further lactation. This indicates that a relationship may exist between a long-lasting SRLV infection and decreased resistance of the udder to bacterial infections, even though the seropositive goats enrolled in this study had no clinical signs of CAE.The aim of this study was to determine whether asymptomatic small ruminant lentivirus seropositive (SRLV-SP) goats were more susceptible to bacterial infection of the udder when lactating by comparing the presence and species of pathogenic bacteria in their milk with the values for seronegative goats (SRLV-SN). Milk samples were collected during morning milking on days 20, 40, 60, 150, and 210 of lactation for three consecutive years and subjected to bacteriological examination. Staphylococcus caprae and S. xylosus were the most frequent strains identified in both SRLV-SP and SRLV-SN goats. The prevalence of pathogenic bacteria was the highest in the 1st lactation, regardless of SRLV status. Moreover, the prevalence of pathogenic bacteria was significantly higher in SRLV-SP goats, but only those in the 5th or further lactation (p = 0.010). This suggests a relationship between long-lasting SRLV infection and susceptibility to bacterial infections of the udder.

Small ruminant mastitis is a serious problem, mainly caused by Staphylococcus spp. Different virulence factors affect mastitis pathogenesis. The aim of this study was to investigate virulence factors genes for biofilm production and antimicrobial resistance to β-lactams and tetracyclines in 137 staphylococcal isolates from goats (86) and sheep (51). The presence of coa, nuc, bap, icaA, icaD, blaZ, mecA, mecC, tetK, and tetM genes was investigated. The nuc gene was detected in all S. aureus isolates and in some coagulase-negative staphylococci (CNS). None of the S. aureus isolates carried the bap gene, while 8 out of 18 CNS harbored this gene. The icaA gene was detected in S. aureus and S. warneri, while icaD only in S. aureus. None of the isolates carrying the bap gene harbored the ica genes. None of the biofilm-associated genes were detected in 14 isolates (six S. aureus and eight CNS). An association was found between Staphylococcus species and resistance to some antibiotics and between antimicrobial resistance and animal species. Nine penicillin-susceptible isolates exhibited the blaZ gene, questioning the reliability of susceptibility testing. Most S. aureus isolates were susceptible to tetracycline, and no cefazolin or gentamycin resistance was detected. These should replace other currently used antimicrobials.

Article Details: Received: 2020-10-14 | Accepted: 2020-11-27 | Available online: 2021-01-31 https://doi.org/10.15414/afz.2021.24.mi-prap.53-57 Abstract The objectives of this study were to determine the relationship of oxidative product levels, using malondialdehyde (MDA) as a marker on occurrence of mastitis and its causing pathogens in two dairy flocks of ewes situated in east and north of Slovakia. The diagnosis of mastitis was performed on the basis of clinical examination of the udder, macroscopic evaluation of milk, with the evaluation of Californian mastitis test (CMT) and bacteriological analysis of individual raw milk samples. From total 537 and 444 halves ewe’s milk samples were 16.6% and 23.2% positive to CMT, respectively. The prevalence of mastitis caused by bacterial pathogenes in the monitored herds was 14.3% to 19.1%, respectively. In all monitored sheep flocks were confirmed predominantly subclinical forms (SM) of intramammary infection (IMI). The highest of etiological agents in all monitored herds had coagulase negative staphylococci and coagulase positive staphylococci especially Staphylococcus aureus . Except for staphylococci were Streptococcus uberis and Streptococcus spp. most frequently pathogens isolated from mastitic sheep. The highest MDA level was observed from clinical cases of mastitis however, increased MDA levels were detectable from subclinical cases. Bacterial isolates from mastitc halves milk samples are different in levels of MDA. In this study, we found that milk samples infected with S. aureus were higher compared to other pathogens. In conclusion, differences in both severities of IMI and mastitis pathogens were associated with differences of MDA in infected udders. Keywords: sheep, milking, mastitis, lipid peroxidation, S. aureus , coagulase negative staphylococci References Contreras, A. et al. (2007). Mastitis in small ruminants. Small Ruminant Research, 68(1-2), 145–153. https://doi.org/10.1016/j.smallrumres.2006.09.011 Fthenakis, G. C. (1995). California mastitis test and White side test in diagnosis of subclinical mastitis of dairy ewes. Small Ruminant Research , 16(3), 271–276. https://doi.org/10.1016/0921-4488(95)00638-2 Hariharan, H. et al. (2004). Bacteriology and somatic cell counts in milk samples from ewes on a Scottish farm. Canadian Journal of Veterinary Research, 68(3), 188–192. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1142138/ Malinowski, E. et al. (2008). Etiological agents of dairy cows’ mastitis in western part of Poland. Polish Journal of Veterinary Sciences, 9(3), 191-194. https://pubmed.ncbi.nlm.nih.gov/17020014/ Mørk, T. et al. (2007). Clinical mastitis in ewes; bacteriology, epidemiology and clinical features. Acta Veterinaria Scandinavica , 49(1), 23. https://dx.doi.org/10.1186%2F1751-0147-49-23 Pyörälä, S. and Taponen, S. (2009). Coagulase-negative staphylococci - Emerging mastitis pathogens. Veterinary Microbiology , 34(2), 3–8. https://doi.org/10.1016/j.vetmic.2008.09.015 Sharma, N. (2011). Oxidative stress and antioxidant status during transition period in dairy cows. Asian-Australian Journal of Animal Science , 24(4), 479–484. https://www.ajas.info/upload/pdf/24-58.pdf Suriyasathaporn, W. (2006). Higher somatic cell counts resulted in higher malondialdehyde concentrations in raw cow´s milk. International Dairy Journal, 16(9), 1088–1091. https://doi.org/10.1016/j.idairyj.2005.11.004 Turk, R. et al. (2017). The role of oxidative stress and inflammatory response in the pathogenesis of mastitis in dairy cows. Mljekarstvo, 67(2), 91–101. https://doi.org/10.15567/mljekarstvo.2017.0201

Subclinical mastitis in small ruminants is of concern due to the animal welfare, economic, public health, productivity, and livelihood impacts that it may pose. A cross-sectional study was conducted from October 2017 to April 2018 in and around Jimma town, Southwest, Ethiopia; to estimate the prevalence of subclinical mastitis, to isolate bacterial pathogens responsible for the occurrence of subclinical mastitis, and to identify risk factors associated with the development of subclinical mastitis in small ruminants. Milk samples were collected from 186 apparently healthy lactating small ruminants, tested on the field with the California Mastitis Test, and samples tested positive were subjected to bacteriological examinations. Out of 372 milk samples collected, 92(24.8%) samples from 70 animals were positive by the California Mastitis Test and these were cultured on different media. Through bacteriological examinations, six isolates of bacteria were identified which include; S. aureus (8.1%), S. epidermidis (10.2%), S. intermidus (2.2%), S. hyicus (1.6%), S. agalactiae (3.2%), and E. coli (12.4%). The highest prevalence of subclinical mastitis recorded was due to Staphylococcus species (22%) followed by E. coli (12.4%) and the least prevalence was due to S. agalactiae (3.2%). The overall prevalence of subclinical mastitis among small ruminants was 37.6%. Age and parity number variations among small ruminants were found important in influencing the prevalence in statistically significant (P = 0.00) extents. The highest prevalence of subclinical mastitis was recorded in old (24.7%) and in small ruminants having >5 parity numbers (24.7%). The high prevalence of small ruminant subclinical mastitis in the study area suggests that intervention strategies their-goal-being prevention and control of subclinical mastitis should be designed; so as to improve the welfare of animals, to save people consuming the milk of small ruminants from zoonotic risks, and to harvest the diverse benefits that may be generated from small ruminant production.

Goat and sheep farming in Brazil relies on an expressive herd, especially in the Northeast region of the country, where small ruminants constitute a relevant economic activity, with milk production being an important source of income in some dry areas of the Northeastern states. However, there are still some sanitary problems in the management of dairy goats, among which mastitis is highlighted, especially that of the subclinical type. Therefore, the aim of this study was to evaluate the use of antibiotics, exclusively or in combination with vaccines, in the control of sub-clinical mastitis in small ruminants. The study was conducted on a rural property located in Santa Maria da Boa Vista-PE. Fifty-three female Saanen dairy goats were allocated into four experimental groups. An antibiotic therapy with a commercial antimicrobial based on cloxacillin was used in group 1. Group 2 received the commercial vaccine indicated for herds with an incidence of Staphylococcus strains and the same antibiotic described for Group 1. Group 3 was evaluated for the exclusive use of vaccination, and Group 4 was the control group. A microbiological examination of the milk was carried out to confirm cases of mastitis. The percentage of udders, infected by coagulase-negative Staphylococcus spp. (CNS) before and after the antibiotic + vaccine treatment was 42.8 and 7.1%, respectively. It was observed that the cloxacillin-based antibiotic could be used alone or in combination with mastitis vaccines to control staphylococcal mastitis in small ruminants. Vaccination alone was not effective in reducing the number of mastitis cases; therefore, a cross reaction against CNS was not observed. Thus, further studies to determine the potential of vaccines to control sub-clinical mastitis in small ruminants are necessary.

This study was conducted to determine the prevalence of coliform bacteria and fungi in ovine and caprine raw milk in Plateau State of Nigeria. In a cross sectional study, a total of 412 milk samples were collected aseptically and 206 questionnaires form where data such as breed, age, parity, lactation stage, floor type, and husbandry system were analyzed. Ewes and does without clinical mastitis were subjected to California Mastitis Test (CMT) to determine the presence of subclinical mastitis. Bacteriological assays and antibiotic susceptibility tests were performed according to standard guidelines. Fungal assays and identification were done according to standard protocol. The overall prevalence of subclinical mastitis for ewes and does were 28.2 and 35.8% respectively. Out of the risk factors examined, age and floor type showed statistically significant relationship with mastitis. Coliforms isolated from milk samples included Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, Enterobacter aerogenes, and Serratia marcescens. The highest coliform isolated among the ewes with 38% prevalence was E. coli and the least was S. marcescens with 2.5%. Among the does, E coli had the highest prevalence as well with 43.1% and E. aerogenes the least with 1.5%. Aspergillus species had 49 isolates out of the 94 fungal isolates (52.1%) of mycotic agents of mastitis in small ruminants. Most antibiotics used in this study showed extremely high level of antimicrobial resistance especially for Amoxicillin-clavulanic acid 45/79 (57.0%) and 53/65 (81.5%) in coliforms isolated from ewes and does respectively. The principle of one health approach which targets the environment, animals and humans should be considered important. Sensitization of pastoralists on good hygienic measures, and treatment of animals by qualified and registered veterinary personnel should be intensified.

BackgroundStaphylococcus aureus is one of the main causative agents of mastitis in small ruminants. Antimicrobial use is the major treatment, but there are many flaws linked to resistance, tolerance or persistence. This study aimed to verify changes in resistance, virulence and clonal profiles of S. aureus isolated from persistent mastitis goat milk before and after enrofloxacin treatment.ResultsMIC increased to at least one antimicrobial in S. aureus isolates after enrofloxacin treatment compared to before. The most detected resistance genes before and after treatment were tetK, tetM, and blaZ, with more resistance genes detected after enrofloxacin treatment (p < 0.05). Occasional variations in efflux system gene detection were observed before and after treatment. Nine virulence genes (hla, fnbA, fnbB, eta, etb, sea, sec, seh, and sej) were detected at both times, and between these, the hla and eta genes were detected more in isolates after treatment. All isolates of S. aureus belonged to the same sequence type (ST) 133, except for two S. aureus isolates prior to enrofloxacin treatment which were classified as ST5 and the other as a new one, ST4966. Isolates of S. aureus 4, 8, and 100 from before and after treatment had identical pulse types, while others obtained from other animals before and after treatment were classified into distinct pulse types.ConclusionThere were occasional changes in the studied profiles of S. aureus isolated before and after treatment of animals with enrofloxacin, which may have contributed to the permanence of bacteria in the mammary gland, even when using traditional treatment, resulting in persistent mastitis.

Staphylococcus aureus (S. aureus) is a major cause of mastitis in small ruminants, and studies on the potential application of acute phase proteins (APPs) in disease biomarkers and understanding the disease mechanism in mastitis affecting small ruminants are limited. Thus, the objective of this study was to determine clinical, histopathological changes and serum concentrations of serum amyloid A (SAA) and haptoglobin (Hp) associated with experimentally induced mastitis using S. aureus. Left mammary quarter in the does was challenged with sterile Ringers buffered salt solution as group 1 (control animals; n = 6) and S. aureus (1.5 × 108 cfu/ml) as group 2 (inoculated does; n = 5) respectively. The animals were monitored at various time intervals for the signs of mastitis and serum concentrations of Hp and SAA. Majority of the animals in the inoculated group showed typical signs of acute mastitis characterized with fever, warm, painful, and swollen mammary gland as early as 24-h post-inoculation (PI). There was significant increased (p < 0.05) in the levels of Hp and SAA in the serum of inoculated animals at 24-h post-inoculation. Histopathological changes in the mammary gland of the inoculated goats included generalized and severe infiltration of the interstitial spaces with polymorphonuclear neutrophils (PMN), severe necrosis of secretory cells, and hyperplastic epithelial and luminal lining. In conclusion, inoculation of S. aureus intramammarily leads to an increment of Hp and SAA at 24-h PI which indicates that both APPs played crucial role as biomarkers in detection and monitoring of S. aureus mastitis in goats.