Current Status of Antimicrobial Resistance and Prospect for New Vaccines against Major Bacterial Bovine Mastitis Pathogens

2020 ◽  
Author(s):  
Oudessa Kerro Dego

Economic losses due to bovine mastitis is estimated to be $2 billion in the United States alone. Antimicrobials are used extensively in dairy farms for prevention and treatment of mastitis and other diseases of dairy cattle. The use of antimicrobials for treatment and prevention of diseases of dairy cattle needs to be prudent to slow down the development, persistence, and spread of antimicrobial-resistant bacteria from dairy farms to humans, animals, and farm environments. Because of public health and food safety concerns regarding antimicrobial resistance and antimicrobial residues in meat and milk, alternative approaches for disease control are required. These include vaccines, improvements in housing, management practices that reduce the likelihood and effect of infectious diseases, management systems and feed formulation, studies to gain a better understanding of animal behavior, and the development of more probiotics and competitive exclusion products. Monitoring antimicrobial resistance patterns of bacterial isolates from cases of mastitis and dairy farm environments is important for treatment decisions and proper design of antimicrobial-resistance mitigation measures. It also helps to determine emergence, persistence, and potential risk of the spread of antimicrobial-resistant bacteria and resistome from these reservoirs in dairy farms to humans, animals, and farm environments.

2020 ◽  
Vol 48 ◽  
Author(s):  
Érica Chaves Lucio ◽  
Gisele Veneroni Gouveia ◽  
Mateus Matiuzzi Da Costa ◽  
Mário Baltazar De Oliveira ◽  
Rinaldo Aparecido Mota ◽  
...  

Background: Bovine mastitis remains one of the health problems that cause the most damage to milk producers. The negative impact of mastitis is due to reduced milk production, early slaughter of females, reduced commercial value of the affected animals, losses in the genetic potential of the herd, expenses with medicines and veterinary medical assistance. Staphylococcus spp. stands out as the cause of this disease and has been able to remain in the mammary gland, becoming resistant to several antimicrobials. The aims of the present study were to characterize the phenotypes, genotypes and resistance profiles of Staphylococcus spp. isolates from bovine mastitis cases in the state of Pernambuco, Brazil.Materials, Methods & Results: These isolates were classified according to biochemical tests and the presence of the nuc gene.  The polymerase chain reaction (PCR) for amplification of the mecA and blaZ genes was used to analyze the genetic potentials of antimicrobial resistance. Isolates were also phenotypically tested for resistance to nine antimicrobials (ampicillin, doxicillin, erythromycin, gentamicin, rifampicin, cephalothin, amoxicillin, nalidixic acid and oxacillin). The genetic potentials for biofilm production were evaluated by the amplifications of the icaD, icaA and bap genes. The phenotypic test of gentian violet was used for biofilm formation analyzes. Ninety-three (93.0%) of the isolates among the Staphylococcus spp. samples were classified as Staphylococcus aureus. The lowest percentage of sensitivity observed was for amoxicillin (28.0%). All of the isolates were sensitive to erythromycin and gentamicin, and 15 (15%) exhibited sensitivity to all of the drugs tested. All of the isolates were negative for the mecA gene, and 36 (36%) were positive for blaZ. In the adhesion microplate tests, 44 (44%) of the isolates were capable of biofilm formation. Of these, seven (15.9%) were strong formers, whereas 16 (36.3%) and 21 (47.8%) were moderate and weak formers, respectively. The icaD gene was confirmed in 89 (89%) of the isolates. The icaA gene was confirmed in 61 (61%) samples, and the bap gene in 52 (52%) samples. One of the samples did not possess icaA, icaD or bap and exhibited moderate biofilm formation according to the microplate adherence test. Sixteen isolates simultaneously exhibited the three genes tested for biofilm production (icaA, icaD and bap) and were negative according to the microplate adherence test.Discussion:  The indiscriminate use of antibiotics to treat mastitis is a common practice in the study area, which may have contributed to the high proportion of herds (88.23%; 15/17) with multi-resistant isolates, constituting a selection factor for the dissemination of resistant bacteria among herds.  The absence of the mecA gene in the present study may be associated with the development of resistant bacteria through another mechanism, such as the overproduction of beta-lactamases. The results demonstrate that antimicrobial resistance occurs in Staphylococcus spp. that cause bovine mastitis in herds of Pernambuco and that these isolates have the a great capacity for biofilm formation. It is necessary to sensitize the professionals involved in the milk production chain of Brazil regarding the importance of the adequate use of antimicrobials for the treatment and control of mastitis, since studies in the country indicate the dissemination of resistant bacterial strains.


2020 ◽  
Vol 7 ◽  
Author(s):  
Kangjun Liu ◽  
Luyao Tao ◽  
Jianji Li ◽  
Li Fang ◽  
Luying Cui ◽  
...  

Bovine mastitis is a prevalent disease that causes serious economic problems globally in the dairy industry. Staphylococcus aureus is an important pathogen of bovine mastitis. This study was conducted to characterize S. aureus isolates from clinical bovine mastitis cases in large-scale dairy herds in China. S. aureus was isolated from 624 clinical mastitis cases and confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). In total, 62 S. aureus isolates were obtained. Cluster analysis, genetic diversity, quantification of biofilm formation, antimicrobial resistance, and detection of virulence genes were performed on these isolates of S. aureus. Eight isolates harbored the mecA gene and were sensitive to oxacillin. MALDI-TOF MS cluster analysis revealed that the 62 isolates were divided into three major clusters (I, II, III) and eight main groups (A–H) at the distance level of 700. The agr II was the most prevalent (56.5%). The 62 S. aureus isolates were assigned to seven spa types. The most common spa type was t529(58.1%), followed by t2196 (14.5%), t518 (14.5%), t571(6.5%), t034 (3.2%), t2734 (1.6%), and t730 (1.6%). Five STs were identified from seven representative isolates as follows: ST630/CC8, ST97/CC97, ST50, ST398, and ST705. All isolates had the ability to form biofilm. Antimicrobial resistance was most frequently observed to ciprofloxacin (29%), followed by penicillin (24.2%), and streptomycin (9.6%). All isolates harbored the fnbA, clfB (100%), icaA, and icaD genes. This study provides the basis for the development of bovine mastitis prevention program on large-scale dairy farms.


2015 ◽  
Vol 45 (6) ◽  
pp. 1035-1041
Author(s):  
Ananda Paula Kowalski ◽  
Grazieli Maboni ◽  
Julia Pires Espindola ◽  
Ariane Foletto ◽  
Guerino Bandeira Junior ◽  
...  

Records of in vitro susceptibility tests performed between 1992 and 2011 were retrospectively reviewed in order to evaluate the dynamic profiles of possible changes in antimicrobial resistance of Staphylococcus spp. isolated from milk samples of cows with mastitis during two decades. The results of 2,430 isolates tested by disk diffusion technique for susceptibility to oxacillin, penicillin, ampicillin, cephalexin, norfloxacin, tetracycline, sulfazotrim, gentamicin, and neomycin were analysed. Comparisons were performed between the percentages of resistance to antimicrobials and their classes and also between the decades studied. Additionally, the possible tendency or changes in the behaviour of these pathogens against the major drugs used in the last two decades were evaluated using regression analysis. The highest rates of resistance (P<0.0001) were observed for the beta-lactams (34.3%), with exception of cephalexin (6.9%), and for the tetracyclines (28%). Similar resistance rates (7.6% to 15.7%) were observed among the other drugs. Regression analysis showed a reduction in resistance to penicillin and ampicillin throughout the period, whilst for oxacillin and neomycin a decrease in the resistance was observed during the first decade, followed by an increase. A trend towards decreased resistance was found for sulfazotrim, whereas for the other antimicrobials no decrease was observed. The results indicated no trend towards increased resistance for most antimicrobials tested. Nevertheless, it is necessary to monitor the resistance patterns of these pathogens in order to save these drugs as a therapeutic reserve


KYAMC Journal ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 6-10 ◽  
Author(s):  
Abdullah Akhtar Ahmed ◽  
Md Abdus Salam ◽  
Md Shakhaowat Hossain ◽  
Md Babul Aktar ◽  
Nusrat Akhtar Juyee ◽  
...  

Background: Antimicrobial resistance in pathogens is a growing concern for health. It is a great concern around the globe about the threat of increasing antimicrobial resistance. In response to this concerns, medical experts have proposed initiatives to curtail the spread of antimicrobial resistance in pathogenic bacteria. We have taken this surveillance study in KYAMCH to contain the spread of antimicrobial resistance.Objectives: To determine the prevalence of MRSA from different clinical samples and to record its current status to commonly used anti Staphylococcus antibiotics.Methods: The clinical samples were taken to the laboratory and within four hours cultured for isolates and identification pathogens. Finally, antibiotic sensitivity testing of the isolated Staphylococcus aureus was performed. Results: More than 80% of MRSA isolates were resistant to ampicillin (98%) followed by amoxicillin, cefixime and azithromycin with 94%, 93.5% and 85% respectively and maximum sensitivity toward tobramycin with 86% followed by 85% gentamicin and 79% meropenem.Conclusion: The detected trend in antibiotic resistance patterns of methicillin-resistant and methicillin-sensitive Staphylococcus aureus in this study is alarming. This has created a huge clinical burden in the hospital settings as well as in the community.KYAMC Journal Vol. 9, No.-1, April 2018, Page 6-10


2014 ◽  
Vol 34 (10) ◽  
pp. 947-952 ◽  
Author(s):  
Daniele C. Beuron ◽  
Cristina S. Cortinhas ◽  
Bruno G. Botaro ◽  
Susana N. Macedo ◽  
Juliano L. Gonçalves ◽  
...  

The objective of this study was to evaluate herd management practices and mastitis treatment procedures as risk factors associated with Staphylococcus aureus antimicrobial resistance. For this study, 13 herds were selected to participate in the study to evaluate the association between their management practices and mastitis treatment procedures and in vitro antimicrobial susceptibility. A total of 1069 composite milk samples were collected aseptically from the selected cows in four different periods over two years. The samples were used for microbiological culturing of S. aureus isolates and evaluation of their antimicrobial susceptibility. A total of 756 samples (70.7%) were culture-positive, and S. aureus comprised 27.77% (n=210) of the isolates. The S. aureus isolates were tested using the disk-diffusion susceptibility assay with the following antimicrobials: ampicillin 10mg; clindamycin 2μg; penicillin 1mg; ceftiofur 30μg; gentamicin 10mg; sulfa-trimethoprim 25μg; enrofloxacin 5μg; sulfonamide 300μg; tetracycline 30μg; oxacillin 1mg; cephalothin 30μg and erythromycin 5μg. The variables that were significantly associated with S. aureus resistance were as follows: the treatment of clinical mastitis for ampicillin (OR=2.18), dry cow treatment for enrofloxacin (OR=2.11) and not sending milk samples for microbiological culture and susceptibility tests, for ampicillin (OR=2.57) and penicillin (OR=4.69). In conclusion, the identification of risk factors for S. aureus resistance against various mastitis antimicrobials is an important information that may help in practical recommendations for prudent use of antimicrobial in milk production.


2013 ◽  
Vol 96 (8) ◽  
pp. 4965-4976 ◽  
Author(s):  
Vineet Saini ◽  
J.T. McClure ◽  
Daniel T. Scholl ◽  
Trevor J. DeVries ◽  
Herman W. Barkema

2021 ◽  
Vol 12 ◽  
Author(s):  
Satoshi Katada ◽  
Akira Fukuda ◽  
Chie Nakajima ◽  
Yasuhiko Suzuki ◽  
Takashi Azuma ◽  
...  

Efficient methods for decreasing the spread of antimicrobial resistance genes (ARGs) and transfer of antimicrobial-resistant bacteria (ARB) from livestock manure to humans are urgently needed. Aerobic composting (AC) or anaerobic digestion (AD) are widely used for manure treatment in Japanese dairy farms. To clarify the effects of AC and AD on antimicrobial resistance, the abundances of antimicrobial (tetracycline and cefazolin)-resistant lactose-degrading Enterobacteriaceae as indicator bacteria, copy numbers of ARGs (tetracycline resistance genes and β-lactamase coding genes), and concentrations of residual antimicrobials in dairy cow manure were determined before and after treatment. The concentration of tetracycline/cefazolin-resistant lactose-degrading Enterobacteriaceae was decreased over 1,000-fold by both AC and AD. ARGs such as tetA, tetB, and blaTEM were frequently detected and their copy numbers were significantly reduced by ∼1,000-fold by AD but not by AC. However, several ARG copies remained even after AD treatment. Although concentrations of the majority of residual antimicrobials were decreased by both AC and AD, oxytetracycline level was not decreased after treatment in most cases. In addition, 16S rRNA gene amplicon-based metagenomic analysis revealed that both treatments changed the bacterial community structure. These results suggest that both AC and AD could suppress the transmission of ARB, and AD could reduce ARG copy numbers in dairy cow manure.


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