Subclinical Bovine Mastitis Cases Research Articles

Antimicrobial Activity of Selected Essential Oils against Staphylococcus aureus from Bovine Mastitis

Staphylococcus aureus is a major cause of subclinical mastitis in dairy cows, and its development of antibiotic resistance has limited treatment efficacy. Essential oils (EOs) are natural products with a wide range of antimicrobial properties that could be used to treat bovine mastitis. This study aims to investigate the antimicrobial activity of EOs against S. aureus isolated from subclinical bovine mastitis cases in the State of São Paulo—Brazil. A total of 14 S. aureus isolates were selected, based on the presence of biofilm-forming genes (icaA, icaD, and bap), and were cultured to a final concentration of 103 CFU.mL−1 for the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) analysis of five EOs (Citrus aurantium bergamia—bergamot, Copaifera reticulata—copaiba, Foeniculum vulgare—fennel, Zingiber officinale—ginger, and Ocimum basilicum—basil). The chemical compositions of the EOs were characterized using gas chromatography coupled with a mass-selective detector (GC/MSD). Basil and bergamot EOs exhibited the highest antimicrobial activity against S. aureus strains, with mean MIC/MBC values of 1.561 ± 0.223/2.806 ± 0.255 mg.mL−1 and 2.782 ± 0.228/4.396 ± 0.198 mg.mL−1, respectively. The primary compounds in basil EO were methyl-chavicol, linalool, and α-humulene, while bergamot EO predominantly contained linalyl acetate, limonene, and linalool. This research highlights the potential of basil and bergamot EOs as natural antimicrobial agents for treating bovine mastitis caused by S. aureus, offering a potential alternative to traditional antibiotics and contributing to animal welfare and public health. In addition, it emphasizes the need for further studies to validate the long-term effects, optimal dosages, and application methods.

Determination of antibiotic resistance and biofilm formation in Klebsiella strains isolated from bovine mastitis cases

Mastitis is diseases of dairy cows with a high economic impact. Bovine mastitis is caused by a wide range of bacterial pathogens. As one of the major environmental pathogens Klebsiella ssp. was investigated in this study by some phenotypic characteristics like antibiotic resistance patterns and biofilm formation properties. A number of 483 cows by dairy farms around the Konya were examined by California Mastitis Test (CMT) producing 36 positive in terms of subclinical mastitis. A further 19 samples from clinical mastitic udders were also collected. Samples were inoculated onto Trypticase Soy Agar medium enriched with sheep blood and incubated aerobicaly for 24-48 hours at 37 °C. By morphological, biochemical and cultural charcateristics 14 isolates out of 37 coliform were identified as Klebsiella ssp. The double disc synergy method and Congo Red Agar test were used to perform antibiotic susceptibility and in vitro slime forming properties, respectively. Resistances to the antibiotics Ampicillin, Carbenicillin, Cephotaxime, Chloramphenicol, Erythromycin, Gentamicin, Neomycin, Oxytetracycline, Sulphamethoxazole/Trimpethoprim, Amoxicillin-Clavulanate and Imipenem were 78.5%, 78.5%, 35.7%, 42.8%, 100%, 7%, 7%, 50%, 14%, 21% and 7%, respectively. Three of the total isolets produced biofilm only. This appears to the first report on ESBL producing Klebsiella ssp from subclinical cases of bovine mastitis in Konya, Türkiye. Presently, two numbers of antimicrobial combinations to treat bovine cases are recommended by this work. In conclusion, because of costly challange nature of Klebsiella caused bovine mastitis implemantation of an effective mastitis control program should be used in local farms from Konya.

Detecção de β-lactamase, blaZ e mecA em amostras de Staphylococcus aureus resistentes à penicilina isoladas de mastite bovina em Garanhuns, Brasil

There are few reports in the literature about genetic determinants of resistance to β-lactams in Staphylococcus aureusisolated from dairy cattle located in the municipality of Garanhuns, state of Pernambuco, Brazil. Thus, this study aimed to investigate the production of β-lactamase and the presence of the blaZ and mecA genes in penicillin-resistant S. aureus isolated from cases of subclinical bovine mastitis in the city of Garanhuns. Forty-six strains of penicillin-resistant S. aureus were evalu-ated using the nitrocefin disc test and duplex PCR. The results revealed that 45 strains (97.8%) were positive for β-lactamase production and 44 (95.7%) carried the blaZ gene. Among the latter, 43 (97.7%) were β-lactamase producers and only one (2.3%) was not. The mecA gene was not detected in any of the isolates investigated. The results suggest that enzymatic inacti-vation is the main β-lactam resistance mechanism expressed by S. aureus in the herds analyzed.

Evaluation of the matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) system in the detection of mastitis pathogens from bovine milk samples

MALDI-TOF is a chemistry analytical tool that has recently been deployed in the identification of microorganisms isolated from nosocomial environments. Its use in diagnostics has been extremely advantageous in terms of cost effectiveness, sample preparation easiness, turn-around time and result analysis accessibility. In the dairy industry, where mastitis causes great financial losses, a rapid diagnostic method such as MALDI-TOF could assist in the control and prevention program of mastitis, in addition to the sanitation and safety level of the dairy farms and processing facility. However, the diagnostic strengths and limitations of this test method require further understanding. In the present study, we prospectively compared MALDI-TOF MS to conventional 16S rDNA sequencing method for the identification of pathogens recovered from milk associated with clinical and subclinical bovine mastitis cases. Initially, 810 bacterial isolates were collected from raw milk samples over a period of three months. However, only the isolates (481) having both 16S rDNA sequencing and MALDI-TOF identification were included in the final phase of the study. Among the 481 milk isolates, a total of 26 genera (12 g-postive and 14 g-negative), including 71 different species, were taxonomically charecterized by 16S rDNA at the species level. Comparatively, MALDI-TOF identified 17 genera (9 g-positive and 8 g-negative) and 33 differernt species. Overall, 445 (93%) were putatively identified to the genus level by MALDI-TOF MS and 355 (74%) were identified to the species level, but no reliable identification was obtained for 16 (3.3%), and 20 (4.2%) discordant results were identified. Future studies may help to overcome the limitations of the MALDI database and additional sample preparation steps might help to reduce the number of discordances in identification. In conclusion, our results show that MALDI-TOF MS is a fast and reliable technique which has the potential to replace conventional identification methods for common mastitis pathogens, routinely isolated from raw milk. Thus it's adoption will strengthen the capacity, quality, and possibly the scope of diagnostic services to support the dairy industry.

Prevalence and characterization of Staphylococcus aureus isolates from subclinical bovine mastitis in southern Xinjiang, China

Staphylococcus aureus is one of the major pathogens causing mastitis in dairy herds. The colonization of dairy cows and subsequent contamination of raw milk by S. aureus, especially strains exhibiting multidrug resistance and biofilm-forming and toxin-producing abilities, remains an important issue for both dairy farmers and public health. In this study, we investigated the prevalence, antimicrobial susceptibility, biofilm formation, and genetic diversity of S. aureus from subclinical bovine mastitis in dairy farms located in southern Xinjiang, China. Sixty-five isolates from 84 subclinical mastitic milk samples were identified as S. aureus. The resistance rates to penicillin, erythromycin, clindamycin, tetracycline, gentamicin, linezolid, rifampicin, quinupudin-dafupudin, ciprofloxacin, norfloxacin, and chloramphenicol were 58.5, 44.6, 40.0, 18.5, 12.3, 10.8, 9.2, 6.2, 4.6, 4.6, and 1.5%, respectively. All isolates were susceptible to cefoxitin, sulfamethoxazole-trimethoprim, and vancomycin. Isolates from farm A showed a significantly higher resistance rate to tetracycline (16.9%) than those from farm B (1.5%). The most frequently detected virulence factors were hla (96.9%, 63/65) and hlb (100.0%, 65/65). The percentage rates of the staphylococcal enterotoxin genes sea, sec, sed, seg, seh, sei, and sej in S. aureus isolates were 4.6, 33.8, 27.7, 3.1, 41.5, 41.5, and 7.7%, respectively. The percentage rate of the sec gene in isolates from farm B (30.8%) was significantly higher than that of farm A (3.1%). The percentage rates of the tsst and pvl genes in S. aureus isolates were 26.2 and 40.0%. The percentage rate of the pvl gene in isolates from farm B (32.3%) was significantly higher than that of farm A (7.7%). The adhesion molecules fnbA, fnbB, clfA, clfB, and cna were detected in 21 (32.3%), 23 (35.4%), 65 (100.0%), 65 (100.0%), and 65 (100.0%) isolates, respectively. The percentage rates of the icaA, sarA, tcaR, ccp, luxS, and sigB genes in S. aureus isolates were 69.2, 100.0, 86.2, 95.4, 84.6, and 100.0%, respectively. The fnbB and icaA genes were more frequently detected in isolates from farm A (29.2 and 40.0%, respectively) than those from farm B (6.2 and 29.2%, respectively). The luxS gene was more often found in isolates from farm B (50.8%) than those from farm A (33.8%). Using the microplate method, 61.5, 26.2, and 10.8% of the isolates showed weak, moderate, and strong biofilm-forming abilities, respectively. Different clonal complex (CC) and spa-types were identified, including CC81, CC398, CC88, CC5405, and CC5406. Importantly, in this study we report for the first time 41 new sequence types (ST) among 44 distinct ST. These results indicated high genetic diversity of S. aureus involved in subclinical bovine mastitis in southern Xinjiang, China. The results also showed that S. aureus from subclinical bovine mastitis cases in southern Xinjiang, China, were mainly resistant to β-lactams, erythromycin, and clindamycin. Also, biofilm- and adhesion-related genes, which are increasingly known as important virulence factors in the pathogenesis of S. aureus infections, were detected at a high rate. This study could help identify predominant clones and provide surveillance measures to decrease or eliminate S. aureus contamination in raw milk of dairy cows with subclinical mastitis.

Staphylococcus argenteus: An emerging subclinical bovine mastitis pathogen in Thailand.

Background and Aim:Staphylococcus argenteus is an emerging species of the Staphylococcus aureus complex. It has usually been misidentified as S. aureus by conventional methods and its characteristics. S. argenteus is potentially emerging in both humans and animals with an increasing global distribution. This study aimed to differentiate and identify S. argenteus from S. aureus collected and isolated from milk samples of subclinical bovine mastitis cases in Maha Sarakham Province, Northeastern Thailand.Materials and Methods:Forty-two isolates of S. aureus were studied from 132 individual milk samples collected from subclinical bovine mastitis cases of 15 dairy farms in three districts of Maha Sarakham, Thailand. The identification was confirmed by conventional and immune-agglutination methods. Fifteen representative isolates which were suspected as being S. argenteus were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).Results:The result from MALDI-TOF MS confirmed that seven from 15 isolates were S. argenteus and eight isolates were S. aureus.Conclusion:This study indicated that MALDI-TOF MS used as an identification and classification method could accurately differentiate the novel species, S. argenteus, from the S. aureus complex which is usually misdiagnosed. In addition, the identification of S. argenteus seems to be very limited in technical difficulty despite the fact that it may be the important causative pathogen in bovine mastitis as well as a pathogenic bacterium in food and milk. Therefore, it is essential for both bovine medicine and veterinary public health to emphasize and recognize this bacterial pathogen as an emerging disease of staphylococcal bacteria that there is a need for further study of S. argenteus infections.

Short communication: Detection and molecular characterization of methicillin-resistant Staphylococcus aureus isolated from subclinical bovine mastitis cases in China

This study investigated the antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) isolated from cases of subclinical bovine mastitis in China, as well as resistance mechanisms and virulence genes encoding adhesins and toxins. We determined antimicrobial susceptibility using the disk diffusion method, and analyzed resistance, adhesin, and toxin genes using PCR. We confirmed MRSA in 73 of 498 (14.7%) Staph. aureus isolates recovered from subclinical mastitic milk samples. All isolates were positive for mecA. The MRSA isolates showed high resistance to penicillin (100.0%), gentamicin (100.0%), and tetracycline (98.6%). All MRSA isolates harbored resistance genes blaZ (penicillin), aacA/aphD (gentamicin), and tetM (alone or in combination with tetK, tetracycline). Moreover, all isolates carried the adhesin genes fnbpA, clfA, clfB, cna, sdrE, and map/eap, and most carried sdrC (98.6%), sdrD (95.9%), bbp (94.5%), and ebpS (80.8%). The toxin genes seh, hla, and hld were present in all isolates, and most isolates carried sea (71.2%), seg (84.9%), sei (82.2%), lukE-lukD (97.3%), and hlg (72.6%). These findings of high-level resistance to antimicrobials commonly used in dairy cattle should lead to calls for antibiogram analysis before antimicrobial therapy. The high frequency of adhesin and toxin genes in MRSA indicates their potential virulence in bovine mastitis in China.

Epidemiological investigation of subclinical bovine mastitis in Algeria and molecular characterization of biofilm-forming Staphylococcus aureus

Thirty dairy farms were selected for this study; the first objective of our study was to investigate the prevalence of subclinical bovine mastitis (SCM) in Eastern Algeria, from 600 lactating cows, and to identify potential risk factors associated with the occurrence of bovine mastitis and bacteria isolation using logistic regression. The second objective was to evaluate biofilm formation capacity and detect biofilm-associated genes of S. aureus, isolated from SCM cases. Molecular typing was investigated by spa typing. The prevalence of mastitis at cow and quarter level was 37.66% (226/600) and 27.17% (555/2042), respectively. Stage of lactation, cow breed, milk production, and the study area were factors associated with SCM. In addition, the most frequent pathogens isolated from mastitic milk were coagulase-negative staphylococci (CNS), E. coli, and S. aureus. The study area was highly associated with SCM caused by S. aureus; cows from Setif province were 18 times more affected with SCM caused by S. aureus compared to cows from Batna province (OR = 18.6, 95%CI 2.038-171.2), but were less affected with SCM caused by CNS isolates (OR = 0.17, 95%CI 0.033-0.868). Moreover, cows with milk production less than 10L per day increased (p < 0.05) the prevalence of mastitis caused by E. coli. All the S. aureus isolates had biofilm-forming ability, and 41.66% of isolates were positive for adhesion genes (icaA, icaD, fbnA, and clfA). This study, therefore, warrants the need for improving sanitary measures and strict hygienic measures, and presents the first insight into biofilm-forming ability of S. aureus strains causing mastitis in dairy herds in Algeria, which will help in tracking the evolution of epidemic strains responsible for causing bovine mastitis.

Short communication: Antimicrobial resistance and virulence genes of Enterococcus faecalis isolated from subclinical bovine mastitis cases in China

This study aimed to investigate the antimicrobial resistance and virulence genes of Enterococcus faecalis isolated from subclinical bovine mastitis cases in China. Enterococcus faecalis isolates were identified by 16S rRNA amplification and sequencing. Antimicrobial susceptibility was determined by the disc diffusion method. Antimicrobial resistance and virulence genes were tested by PCR. Overall, E. faecalis was recovered from 81 of 1,787 (4.5%) mastitic milk samples. The isolates showed high resistance against tetracycline (87.7%) and erythromycin (79.0%). The most prevalent resistance genes found in the E. faecalis were tetK (96.3%), tetL (79.0%), and tetM (87.7%) for tetracycline and ermC (97.5%) for erythromycin. Moreover, gelE (70.4%), esp (85.2%), efaA (91.4%) were the most common virulence genes. This is the first report to characterize E. faecalis recovered from subclinical bovine mastitis cases in China.

Antibiotic susceptibility of Staphylococcus aureus isolated from subclinical bovine mastitis cases and in vitro efficacy of bacteriophage

Staphylococcus aureus is an opportunistic pathogen that may cause severe infections in livestock, and represents the major cause of mastitis in dairy cows. Currently, instead of using antibiotics, new strategies are sought to reduce this clinical health problem. The aim of this study was to determine the efficacy of phage therapy to kill S. aureus strains obtained from farms located at the State of Guanajuato, México. Thirty-six S. aureus strains from cow milk with subclinical mastitis were isolated and identified, and the susceptibility to antibiotics and four phages also isolated in this work was tested. It was found that more of 90% of S. aureus isolates were not susceptible to six or more antibiotics, and 100% were resistant to penicillin, dicloxacillin, cefotaxime, ampicillin and cephalothin, and 81 and 77%, to tetracycline and cefuroxime, respectively. Fortunately, 100% of S. aureus isolates were susceptible to phages used in this work, which was detected as clear zones using specific phage. It was shown for the first time, that phages used in this study are active against pathogenic S. aureus and might be incorporated into the therapy as an important tool for the control of staphylococcal bovine mastitis, specially to antibiotic-resistant S. aureus strains isolated in farm located at the state of Guanajuato, México; and its use might be extended to other regions inside or outside the country.

Investigation of the antibiotic resistance and biofilm-forming ability of Staphylococcus aureus from subclinical bovine mastitis cases.

A total of 112 Staphylococcus aureus isolates obtained from subclinical bovine mastitis cases were examined for antibiotic susceptibility and biofilm-forming ability as well as genes responsible for antibiotic resistance, biofilm-forming ability, and adhesin. Antimicrobial susceptibility of the isolates were determined by disk diffusion method. Biofilm forming ability of the isolates were investigated by Congo red agar method, standard tube method, and microplate method. The genes responsible for antibiotic resistance, biofilm-forming ability, and adhesion were examined by PCR. Five isolates (4.5%) were identified as methicillin-resistant Staph. aureus by antibiotic susceptibility testing and confirmed by mecA detection. The resistance rates to penicillin, ampicillin, tetracycline, erythromycin, trimethoprim-sulfamethoxazole, enrofloxacin, and amoxicillin-clavulanic acid were 45.5, 39.3, 33, 26.8, 5.4, 0.9, and 0.9%, respectively. All isolates were susceptible against vancomycin and gentamicin. The blaZ (100%), tetK (67.6%), and ermA (70%) genes were the most common antibiotic-resistance genes. Using Congo red agar, microplate, and standard tube methods, 70.5, 67, and 62.5% of the isolates were found to be biofilm producers, respectively. The percentage rate of icaA, icaD, and bap genes in Staph. aureus isolates were 86.6, 86.6, and 13.4%, respectively. The adhesion molecules fnbA, can, and clfA were detected in 87 (77.7%), 98 (87.5%), and 75 (70%) isolates, respectively. The results indicated that Staph. aureus from sublinical bovine mastitis cases were mainly resistant to β-lactams and, to a lesser extent, to tetracycline and erythromycin. Also, biofilm- and adhesion-related genes, which are increasingly accepted as an important virulence factor in the pathogenesis of Staph. aureus infections, were detected at a high rate.

Biofilm-producing ability and efficiency of sanitizing agents against Prototheca zopfii isolates from bovine subclinical mastitis

The objectives of the present study were to evaluate (1) the capacity of the microalga Prototheca zopfii isolated from subclinical bovine mastitis cases to form biofilms; and (2) the resistance of these isolates to sanitizing agents. Ten isolates of P. zopfii from cows with subclinical mastitis (somatic cell count >200×103 cells/mL), distributed in 5 dairy farms, were evaluated for their capacity to form biofilms in polystyrene microplate assays and stainless steel coupons, at 25°C and 37°C ± 1°C. Prototheca zopfii were isolated from milk samples via microbiological culture and analyzed by 18S rRNA gene sequencing. Biofilm formation on the coupons was observed by scanning electron microscopy. The resistance to sanitizing agents was assessed using the biofilm-forming P. zopfii isolates in stainless steel coupon assays, which were subjected to 3 sanitizers: peracetic acid, sodium hypochlorite, and iodine solution. To evaluate resistance to the sanitizers, the minimum inhibitory concentration (MIC) technique was performed using decreasing concentrations of the sanitizing agents (20, 10, 5, 2.5, 1.25, 0.625, 0.312, 0.156, 0.078, 0.039, and 0.019g/L). After inoculating the isolates, all concentrations were evaluated at 3 distinct incubation periods (24, 48, and 72 h) to assess the effect of incubation time on the MIC. Using the polystyrene microplate assays, 1 isolate showed weak biofilm production, 5 moderate, and 4 strong, when incubated at 25°C ± 1. For isolates incubated at 37°C ± 1, 6 showed weak biofilm production and 4 moderate. All P. zopfii isolates (n=10) had the capacity to form biofilms on stainless steel coupons. The longer the incubation period of the P. zopfii isolates at different dilutions, the greater the concentrations of sanitizer needed to prevent growth of the microalgae under the tested conditions. We detected a significant effect of sanitizer and time of incubation (24, 48, and 72 h) on MIC values against P. zopfii isolates. The isolates were sensitive in vitro to peracetic acid (MIC90 ≥0.019g/L), sodium hypochlorite (MIC90 ≥0.312g/L), and iodine solution (MIC90 ≥0.625g/L), after 24 h of incubation (where MIC90=concentration needed to inhibit 90% of isolates). Of the tested sanitizers, peracetic acid had the greatest efficiency against P. zopfii. We conclude that P. zopfii isolates are capable of biofilm production, which may contribute to their persistence in a milking and dairy environment.

Characterization of biofilm and coagulase producing Staphylococcus aureus associated with bovine mastitis

Present research was planned to study incidence, virulence factors viz. biofilm and coagulase production and antibiogram of Staphylococcus aureus associated with bovine mastitis. Milk samples (142) of clinical and subclinical bovine mastitis cases from Mumbai and around Mumbai region were processed. From the milk samples processed; 52 (36.61%) Staphylococcus spp. isolates were recovered. Incidence of S. aureus in bovine mastitis was 28.16% (in cows: 41.37% and in buffaloes: 24.77%). The incidence rate of S. aureus in subclinical and clinical mastitis was 17.24% and 30.97% respectively. The results of antibiotic resistance pattern of isolates indicated highest resistance to penicillin (100%) followed by vancomycin and oxacillin (77.5%) and gentamicin (15%). The least resistance was observed to chloramphenicol (12.5%), ceftriaxone (10%), methicillin and cephotaxim (7.5%). Out of 40 S. aureus isolates characterized for biofilm production, overall 32 (80%) isolates were biofilm producing which were confirmed using various methods, viz. CRA (45%), TCP (35%) and PCR (72.5%) of intercellular adhesin gene ica A and ica D. Of 32 biofilm producing S. aureus, 20 (62.50%) were coagulase producing strains and 65.62% of them also showed biofilm production. Out of 40 S. aureus isolates, 26 (65.00 %) were proved to be coagulase producing strains by tube method; whereas by coa PCR assay, 21 (52.5%) isolates showed presence of coagulase gene. Out of 21 coa exhibiting strains of S. aureus, 4 (10%) isolates were of coa genotype A with an amplicon size of 850 bp while 17 (42.5%) S. aureus isolates were of genotype B with an amplicon product of 600 bp. Out of 26 coagulase producing S. aureus, 21 (80.76%) were biofilm producing. Most of biofilm and coagulase producing strains displayed multiple drug resistant.

CHARACTERIZATION OF STAPHYLOCOCCUS AUREUS ASSOCIATED WITH BOVINE MASTITIS

The present research was planned to study incidence, virulence properties and antibiogram of Staphylococcus aureus isolates recovered from bovine mastitis. A total 108 milk samples (48 cows and 60 buffaloes) from clinical and sub-clinical cases of bovine mastitis from different locations of Kolhapur and Sangali districts of Maharashtra state were collected during present investigation. Overall recovery of Staphylococcus spp. was 36 (33.33%) isolates (10 cows + 26 buffaloes) and 30 (27.77%) isolates were confirmed as S. aureus with an incidence rate of 16.66% in cows and 36.66% in buffaloes, whereas 6 (5.55%) isolates were other Staphylococcus spp. The incidence rate of S. aureus in subclinical and clinical mastitis was found to be 35.93% and 15.90% respectively. Conventional tube method for coagulase production, DNAse test and studies on haemolysis production of S. aureus isolates resulted in 9 (30%) CPS, 23 (76.66%) DNAse producing and 21 (70%) hemolytic strains. ABST of 30 S. aureus isolates by disc diffusion method indicated maximum resistance to Vancomycin (90%) followed by Ceftriaxone (80%), Penicillin-G (73.34%), Oxacillin (70%) and Amoxicillin (60%) whereas, the least resistance was observed to Methicillin (6.67%) and Chloramphenicol (10%). Multiple drug resistance was observed in 26 (86.66%) isolates. The PCR amplification of Coagulase gene (coa) of S. aureus isolates yielded 14 (46.66%) coagulase positive isolates with amplification sizes ranging from 600 to 850 bp. Four different coa genotypes were generated based on the sizes of amplicons viz. A, B, C and D. Out of 14 coa exhibiting strains of S. aureus, Genotype A (850 bp) was observed in 7.14% isolates, whereas genotype B (750 bp) in 14.28% isolates, 50% isolates were of genotype C (700 bp) and 28.57% of genotype D (600 bp). Amongst 14 coa positive isolates, 11 were from subclinical mastitis origin and only 3 were from clinical mastitis cases. All coagulase producing strains of S. aureus were haemolytic and DNAse producing with an exception of one DNAse negative strain. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Table Normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Times New Roman; mso-bidi-theme-font:minor-bidi; mso-ansi-language:EN-IN; mso-fareast-language:EN-IN;}

Stability andin vitroantimicrobial efficacy of a nanopropolis formulation intended for intramammary treatment of bovine mastitis

II SIMPÓSIO DE QUALIDADE DE LEITE O II Simpósio de Qualidade de Leite aconteceu nos dias 05, 06 e 07 de setembro de 2014, no Centro de Convenções da Faculdade de Ciências Agrárias e Veterinárias, Unesp, Câmpus de Jaboticabal, SP. Foi um evento organizado por pós-graduandos do Departamento de Medicina Veterinária Preventiva, sob a supervisão do Prof. Dr . Antonio Nader Filho (homenageado do V Congresso Brasileiro de Qualidade de Leite, 2013, pelos importantes trabalhos desenvolvidos na área). Tendo em vista o sucesso obtido na edição anterior, o II Simpósio de Qualidade de Leite apresentou uma nova programação, com palestras que abordaram assuntos atuais relacionados à cadeia do leite no Brasil aliados à presença de palestrantes renomados. Temas como fraudes e adulteração do leite; resíduos químicos; programas de autocontrole e boas práticas de fabricação; zoonoses veiculadas pelo leite; tratamento da mastite; manejo alimentar e ambiental do gado de leite; aproveitamento de dejetos; a importância da extensão rural como uma aliada; o controle estratégico de parasitas e análises sobre CBT e CCS, e uma mesa redonda para discutir a Instrução Normativa nº 62, do Ministério da Agricultura, Pecuária e Abastecimento, foram alguns dos principais assuntos abordados durante o evento. O público esperado envolveu profissionais de indústrias de laticínios, criadores de gado de leite, estudantes de graduação e de pós-graduação da área de qualidade de leite, pesquisadores e demais profissionais do segmento envolvidos com a pecuária leiteira. Outro aspecto inovador do Simpósio foi a apresentação de resumos expandidos de trabalhos científicos e de extensão rural relacionados ao tema de qualidade do leite. Os resumos estão publicados na Revista Brasileira de Higiene e Sanidade Animal , no formato de resumo expandido, o que permite maior visibilidade e divulgação das pesquisas relacionadas ao tema. Dessa forma, a Comissão Organizadora do II Simpósio de Qualidade de Leite, agradece a todos que de alguma forma colaboraram para o sucesso dessa edição. Em especial, agradecemos nossos patrocinadores, pelo apoio essencial ao evento e aos palestrantes, que foram de suma importância para o enriquecimento e sucesso do Simpósio. Muito obrigado a todos pela participação! Comissão Organizadora II Simpósio de Qualidade de Leite URL do Portal: http://www.higieneanimal.ufc.br/seer/index.php/index/index 2014 setembro; 8(5 Supl 1): p. 01- 552

Draft Genome Sequence of Staphylococcus simulans UMC-CNS-990, Isolated from a Case of Chronic Bovine Mastitis

Coagulase-negative staphylococci are frequently isolated from cases of subclinical bovine mastitis. Reported here is a draft genome sequence of Staphylococcus simulans UMC-CNS-990, an isolate recovered from a chronic intramammary infection of a Holstein cow. Unexpectedly, a cluster of genes encoding gas vesicle proteins was found within the 2,755-kb genome.

Isolation and antibiogram of Staphylococcus, Streptococcus and Escherichia coli isolates from clinical and subclinical cases of bovine mastitis

Aim: The present study was aimed to isolate and evaluate the continuous change in the pattern of drug resistance showed by different mastitogenic organisms, isolated from clinical and subclinical cases of mastitis. Materials and Methods: The study was carried out using 150 milk samples received from various clinical and subclinical cases, from which the causative organisms were isolated and subjected to in vitro antibiotic sensitivity test. Results: The bacteriological analysis of the samples indicated the presence of both Gram positive and Gram negative organisms followed by isolation of isolates like Staphylococcus, E. coli, Streptococcus, Bacillus, Corynebacterium, Listeria, Klebsiella. The in vitro sensitivity of Staphylococcus, E. coli and Streptococcus isolates revealed that they were more sensitive towards newer antimicrobials like Levofloxacin and Enrofloxacin. Conclusion: The prevalence of Staphylococcus was found to be maximum followed by Streptococcus and E. coli among the isolated organisms. Levofloxacin and Enrofloxacin were found to be most effective against the targeted isolates.

Minimum inhibitory concentrations of Staphylococcus aureus recovered from clinical and subclinical cases of bovine mastitis

Antimicrobials are often used for treatment of bovine mastitis and the possibility of selection for resistant bacteria must be considered. The objectives of this study were to determine the minimum inhibitory concentration of Staphylococcus aureus recovered from cases of clinical and subclinical bovine mastitis, and to determine the prevalence of multidrug resistance in this population. Milk samples were collected from cows on commercial dairy herds (n=13), including quarters (n=1,574) of cows with subclinical mastitis cases, and cows experiencing clinical mastitis cases (n=608). Selected Staph. aureus isolates, obtained from clinical (n=58) and subclinical (n=58) mastitis cases, were used to determine minimum inhibitory concentrations of 12 selected antimicrobials. Of Staph. aureus isolates tested, 87 (75%) did not exhibit resistance to any antimicrobial, 28 (24.1%) exhibited resistance to 1 (n=21) or 2 (n=7) classes of antimicrobials, and 1 (0.9%) exhibited multidrug resistance. All Staph. aureus (clinical and subclinical cases) were inhibited by the range of concentrations tested for ceftiofur and oxacillin. Moreover, no isolates obtained from clinical mastitis cases exhibited resistance to cephalothin, penicillin-novobiocin, or sulfadimethoxine. Of isolates, 3 exhibited resistance to enrofloxacin. Of isolates exhibiting resistance to more than 1 antimicrobial, independent of antimicrobial class, the combination of erythromycin and tetracycline, and ampicillin and penicillin accounted for the majority of resistance. Of isolates tested, 19% were resistant to tetracycline and 14% were resistant to penicillin. Survival curves of Staph. aureus relative to minimum inhibitory concentration demonstrated heterogeneity among case types for ceftiofur, cephalothin, and erythromycin. Multidrug resistance was identified in only 1 isolate obtained from a single farm.

Limited genetic diversity of Aerococcus viridans strains isolated from clinical and subclinical cases of bovine mastitis in Slovakia

The Aerococcus viridans isolates from bovine mastitis in Slovakia were isolated and characterized by classical microbiological and biochemical, and molecular techniques including IGS-PCR and rep-PCR, ARDRA and 16S rDNA gene sequencing. The substantial variability of antibiotic resistance patterns was observed. The majority of strains were resistant to beta-lactam antibiotics, the resistance to tetracycline was observed in 3 tested strains, resistance to lincomycin was found in 4 strains and practically all tested strains were sensitive to neomycin and ciprofloxacin. While variable at a phenotypic level, no significant genetic variability among A. viridans isolates was detected by molecular DNA based methods. The data obtained suggest that a few A. viridans strains spread among cow's population in Slovak farms.

Prevalence and Molecular Mechanism of Macrolide and Lincosamide Resistance in Staphylococci Isolated from Subclinical Bovine Mastitis in Turkey

Macrolide and lincosamide (ML) resistance and the related resistance genes of staphylococci were assessed from cases of bovine subclinical mastitis. Of the 104 Staphylococcus aureus and 62 coagulase negative staphylococcus (CoNS) isolates, 26 (25%) and 12 (19.4%) were resistant to ML, respectively. While constitutive ML resistance phenotype accounted for 15.4% (16/104) of S. aureus and 8.1% (5/62) of CoNS, inducible ML resistance phenotype accounted for 2.9% (3/104) of S. aureus and 3.2% (2/62) of CoNS. Among erythromycin-resistant isolates, single or various combination of different resistance genes were detected. The results of this study showed that ML resistance was prevalent among staphylococci from subclinical bovine mastitis cases in Hatay, Turkey. Therefore, a continuous surveillance is necessary to minimise the spread of antimicrobial-resistant staphylococci.