Open access peer-reviewed chapter

Etiology of Bovine Mastitis

Written By

Muhammad Shoaib, Amjad Islam Aqib, Muhammad Aamir Naseer, Zeeshan Ahmad Bhutta, Wanxia PU, Qaisar Tanveer, Iqra Muzammil, Muhammad Fakhar-e-Alam Kulyar, Muhammad Salman Younas and Muhammad Hammad

Submitted: December 6th, 2020Reviewed: May 24th, 2021Published: August 17th, 2021

DOI: 10.5772/intechopen.98543

Chapter metrics overview

151 Chapter Downloads

View Full Metrics


Mastitis in dairy animals is the primary concern of dairy farmers, which is the most common disease that causes huge economic losses in the dairy industry. The economic losses due to mastitis are from a reduction in milk yield, condemnation of milk with antibiotic residues, veterinary treatment costs, and death. In addition, some mastitis pathogens also cause serious human diseases associated with the contamination of milk or milk products with bacteria or their toxins. Bovine mastitis is mainly caused by a wide range of environmental and contagious bacterial mastitis pathogens. Contagious pathogens are those whose main reservoir is the infected udder. Contagious pathogens mainly spread among animals during milking process whereas environmental pathogens spread from environment to udder at any time. The source of the environmental pathogens is the surrounding environment of an animal. The major contagious pathogens include Staphylococcus aureus, Streptococcus agalactiae, and Mycoplasma spp. and the minor contagious pathogens include Corynebacterium bovis and others. Major environmental pathogens include coliform bacteria (Escherichia coli, Klebsiella spp., Enterobacter spp. and Citrobacter spp.), environmental streptococci (Strep. dysgalactiae, Strep. uberis). This chapter covers detailed review of published data on contagious and environmental pathogens responsible for bovine mastitis.


  • Bovine mastitis
  • Etiology of mastitis
  • Microorganism
  • Contagious pathogen
  • Environmental pathogen

1. Introduction

Mastitis is an inflammation of the mammary gland caused by microorganisms or trauma. Its purpose is to eliminate or neutralize infectious agents or repair injury and set the stage for healing and restoring normal functioning [1]. Inflammation can be caused by many types of injuries, including infectious agents and their toxins, chemical irritation, and physical trauma [2, 3]. In dairy cows, mastitis is most often caused by microorganisms, usually bacteria that enter the udder and multiply in the milk and gland tissues, producing toxins and other virulence factors that cause direct damage to the gland tissue [4]. Mastitis is one of the main diseases of dairy animals (e.g., cattle, buffalo, sheep, goats and camels). It causes several problems including reduction in milk production, affect quality of milk to be processed and milk and dairy products quality as well as a huge financial loss for the dairy industry [5]. Mastitis affects the physical and chemical properties, bacteriological load, and other milk qualities. In the milk of infected animals, pathogens and their toxins may present. So, the disease is also very important from the consumer’s health risk point of view [6]. The presence of heat-resistant pathogenic spores and toxins in commercially available raw milk poses a serious threat to consumer’s health and wellbeing [7, 8, 9].

Mastitis can be caused by a single pathogen or combination of two pathogens. According to the US National Mastitis Council Guidelines for diagnosis of mastitis, isolation of more than three pathogens in a milk sample is considered contamination. About 137 microbes have been isolated from milk [4]. Environmental microorganisms that can cause mastitis include Strep. uberis, Strep. agalactiae, Trueperella pyogenes, Enterobacter aerogenes, Klebsiellaspp., E. coli,some yeast, and fungi [10]. In herds that lack an effective mastitis control program, infectious agents such as Staphylococcus aureusand Streptococcus agalactiaeare generally considered to be the main organisms causing mastitis [11]. The incidence rates of these pathogens were significantly reduced with strict adoption of mastitis control programs in countries with well-established dairy farming systems. However, in well managed dairy farms with strict application of mastitis control programs environmental pathogens are of more concern in well-established dairies [12, 13]. Prior to the implementation of mastitis control strategies such as 5-point mastitis control program and later on 10-point mastitis control program by National Mastitis council, contagious mastitis pathogens were considered as the main causative agents of mastitis in dairy cows, even in developed countries [14, 15, 16]. The epidemiological field study of mastitis concluded that agents such as Staphylococcus aureus, Streptococcus agalactiaeand Escherichia coliaccount for over 75% of mastitis cases, and Staphylococcus aureusis the most prevalent, resistant and challenging candidate among them [8, 15, 17]. The bacterial entry into mammary glands leads to bacteria interaction with the mammary epithelial cells, resulting in local inflammatory signs and deteriorated milk quality. Environmental microorganisms can accidentally enter the udder during intramammary injection [18]. Moreover, contagious intramammary infection can be transmitted by milker’s hands, cleaning towels, flies, and milking machines [19, 20]. Streptococcus dysgalactiae, Strep. uberis, Klebsiellaand E. coliare the most common environmental pathogens, gaining access to udder at any time including during milking process. Clinical mastitis manifest symptoms such as udder/quarter swelling, abnormal milk quality and quantity, and anorexia [21, 22, 23].


2. Contagious mastitis pathogens

2.1 Major pathogens

2.1.1 Staphylococcus aureus

Staphylococcus aureusis major pathogen causing infectious mastitis in dairy cows, with prevalence of 43–74% [24]. It is a gram-positive, catalase and coagulase-positive, non-spore-forming, oxidase-negative, immobile, and facultative anaerobic bacteria [25]. Staphylococcus aureusis the most common mastitis pathogen [26]. While it is possible to reduce the incidence of S. aureusmastitis through hygienic milking and proper management systems, it remains a major challenge for dairy farms with a prevalence rate higher than 60% [8, 27]. The incidence of S. aureusmastitis differs due to changes in hygienic milking practices and general differences in the management of infectious mastitis on farm [20, 28]. Optimal milking parlor hygiene can considerably decrease the incidence of new S. aureusmastitis in the herd but cannot exclude existing cases in the herd [29]. Based on early observations by Neave et al. [29], numerous studies have reported that treatments can decrease the number of new cases of mastitis [12] but cannot eliminate persistent infections in the herd. In the United States, the occurrence of clinical and subclinical S. aureusmastitis is 10–45% and 15–75%, respectively [30]. Its virulence is due to its ability of producing wide array of virulence factors that enhance its pathogenicity and persistence in epithelial linings of udder. These virulence factors contribute to microbial attachment, colonization, longer persistence and escaping the immune response. Such abilities make S. aureusone of the most important challenging pathogen for animal and human health [31, 32]. Staphylococcus aureusisolated from udder infections in ruminants are found producing a layer of slime around them, which enables them to resist host immune system and antibiotics [8]. This slime layer also helps in adherence and colonization of pathogen in udder glandular cells [33]. Staphylococcus aureusvirulence factors and pathogenicity associated mechanisms such as resistance to phagocytosis, adherence and biofilm formation enable it to cause persistent and chronic infections [34].

Staphylococcus aureushas numerous virulence factors, that can be divided into two categories. These include non-secretory factors which are surface restricted structural component that acts as virulence factors, and secretory factors that are produced by bacterial cells, and act on a variety of target sites in the host. Both secretory and non-secretory factors enable this pathogen to evade host’s defenses and colonize the udder [35, 36, 37]. Microbial membrane proteins, including fibrinogen-binding protein, collagen-binding protein, penicillin-binding protein, elastin-binding protein, and lipoteichoic acid can act as non-secretory virulence factors [36, 38, 39]. Cell wall binding factors such as lipoprotein, peptidoglycans, protein A, phthalic acid, protease, and β-lactamase can act as secretory virulence factors [39, 40]. Other virulence factors related with the cell surface include exopolysaccharides, biofilms, and capsules [37, 41, 42]. Overall, Staphylococcus aureushas more than 13 secreted proteins and 24 surface proteins involved in immune evasion [43], as well as about 15–26 proteins involved in biofilm formation [44]. The most familiar secretory virulence factors are toxins, including non-enteric exfoliative toxins, staphylococcal enterotoxins, leucocidin, toxic shock syndrome toxin 1, and hemolysins (α, β, δ, and γ) [45]. Likewise, enzymes like staphylokinase, coagulase, phosphatase, DNase, phospholipase, lipase, and hyaluronidase are also virulence factors of Staphylococcus aureus[7, 46, 47].

2.1.2 Streptococcus agalactiae

Streptococcus agalactiaeis the contagious mastitis pathogen and the infected mammary gland acts as reservoir of the bacterium in the herd. Transmission of the bacterium is mainly through milking equipment, milker’s hands, and regular towels [48]. Developed dairy sectors have overcome this challenge by optimal managemental and biosecurity practices but Streptococcus agalactiaeis still an important cause of intramammary infections (IMI) around the globe [16, 49, 50, 51]. A study from dairy farms in Colombia indicated a higher prevalence of Streptococcus agalactiaeinduced IMI in cattle ranging from 28–35% [52]. Moreover, Streptococcus agalactiaereemergence has also been reported in Northern Europe [53]. Non-dairy sources (e.g., humans) have been reported to be the main cause of reintroduction of this pathogen into dairy herds [54].

Capsular polysaccharide is the most important virulence factor of Streptococcus agalactiae[55], which protects bacteria from phagocytosis by macrophages and subsequent depletion [55]. An additional virulence factor for S. agalactiaeis the surface protein, which provides resistance to proteases. Emaneini et al. [55] discovered that 89% of cattle mastitis causing Streptococcus agalactiaeisolates possess gene encoding (rib). Streptococcus agalactiaeis extremely contagious but responds well to antibiotic treatment, allowing its removal from the herd with effective mastitis control programs [56]. As a result of standard managemental practices, Streptococcus agalactiaemastitis has been significantly reduced and is now rare in developed dairy systems [57].

2.1.3 Mycoplasma spp.

Mycoplasmais a highly contagious microorganism, but not to the same extent as Streptococcus agalactiaeor Staphylococcus aureus. However, Mycoplasmadamages the secretory tissue and causes abscess and lymph node fibrosis as well as gland fibrosis [4, 16]. Animals of any age and at any time of lactation are sensitive to Mycoplasmainfection. Those in the early stages of lactation are susceptible to Mycoplasmainfection and may be isolated from asymptomatic high producing animals. Mycoplasmosis is usually associated with the appearance of mastitis, the appearance of new animals, previous respiratory or joint diseases, and herds of cattle that have not responded to antibiotic treatment [18, 58]. Mycoplasmainfection is suspected if there is at least one recurrence of mastitis, asymptomatic disease, and no response to treatment [59].

The species detection in Mycoplasmamastitis is usually carried out by PCR with defined endpoints for Mycoplasma bovis, Mycoplasma bovigenitelium, Mycoplasma californicum, and Mycoplasma alkalescens.Laboratory monitoring of dairy herds showed the presence of Mycoplasmaspp. in at least one cow of the herd [60]. Herd-level study of 463 Northwest Dairy Association miking herds reported that 93 herds were positive for Mycoplasmamastitis. Cattle in milk were noted more prone to Mycoplasmainfection. Moreover, Mycoplasmainfection was noted indirectly related to herd size [61].

Mycoplasmamastitis is less common than other bacterial mastitis, but it can cause severe mammary infections and has unique epidemiology and risk factors [58, 61]. It can usually be distinguished from mastitis caused by staphylococci and streptococci because it is (1) highly infectious, (2) infects more than one quarter, (3) causes significant milk yield loss, (4) is often resistant to antibiotic treatment, and (5) can become purulent. In some cases, affected cows may appear normal and not show obvious clinical signs. Since Mycoplasmamastitis is considered incurable, culling remains the most commonly recommended control measure [58, 62].

2.2 Minor contagious pathogens

2.2.1 Mannheimia spp.

Mastitis, caused by Mannheimia(formerly known as Pasteurella) haemolyticaand Pasteurella multocida, is common in sheep and manifests itself as peracute gangrenous, but less commonly in goats and cattle [63, 64].

2.2.2 Corynebacterium bovis

Corynebacterium bovis (C. bovis)is a common infectious agent, most associated with asymptomatic infections. However, in 7% of cases, the bacteria were isolated from cows with clinical mastitis [16]. From the herds where pathogens that cause infectious mastitis were controlled, it accounted for higher number of clinical cases. There is a continuing discussion about the importance of Corynebacterium bovisinfection for udder health and milk production [16, 19, 21]. Studies have shown that this bacterium has tendency for the teat canal. This characteristic is associated with lipids requirements for its growth (probably inside the keratin plug). It could be possible that C. bovisocclusion of the streak canal may cause competition with other ascending bacterial infections for nutrients, thus decreasing the IMI [15, 16]. Moreover, the small increase in SCC linked with C. bovisinfection may increase the ability of the udder quarter to show response against new intramammary infections. A higher SCC than normal is caused by infection with a minor mastitis pathogens in the udder and increases the udder’s resistance to invasion by other contagious pathogens [1, 65].

In herds with endemic C. bovismastitis, the infection rate was noted lowest in comparison to major pathogens infected herds [15, 66]. Intramammary C. bovisinfections are mostly associated with clinical manifestations but generally have a reasonable increase in somatic cells count. Milk in such infections is usually thicker than normal and milk loss is usually undetectable [16, 22, 23, 67].


3. Environmental pathogens

In modern dairy systems, environmental mastitis is the most common and costly challenge [59]. Environmental mastitic pathogens include various bacteria such as coliform (e.g., Escherichia coli, Klebsiellaspp., Enterobacterspp., etc.),environmental streptococci (e.g., Streptococcus uberis, Streptococcus agalactiae, etc.) [15]. In addition, farm floor, pasture and cattle manure are the main sources of environmental mastitis pathogens, especially E. coliand Streptococcus uberis[68]. Major environmental pathogens causing severe damage to bovine udder include Streptococcus uberis, Streptococcus dysgalactiae, coliforms, and non-aureus staphylococci[69]. Mixed IMI of major and environmental mastitis pathogens frequently cause severe, persistent and non-responsive mastitis, with a significant increase in somatic cell count and obvious clinical manifestations [59].

Due to emerging concern of increasing antibiotic resistance, preventive strategies for controlling environmental mastitis pathogens are needed [47, 70]. Control of significant risk factors, pasture management, optimal managemental and feeding practices is a prime goal of such strategies. There are preventive mastitis vaccines in the market that are reported to reduce the infection, but unfortunately, none of them provided promising results [53]. Understanding the transmission pathways, better diagnostic tools and implementation of mastitis control program in efficient way can lead to drastically lessen the mastitis burden in dairy industry [71, 72, 73].

3.1 Major environmental pathogens

3.1.1 Environmentalstreptococci

Environmental streptococcal species are considered as one of the significant pathogens that cause clinical and subclinical mastitis in dairy herds. Among these, Streptococcus uberisis the most common mastitis pathogen that damages the bovine udder. Mastitis control measures have minimal effect on the incidence of mastitis, caused by environmental Streptococcusspecies, coliforms and some non-aureus staphylococci [74]. Dairy environment is the key risk factor that leads to the development of mastitis particularly due to S. uberis, S. dysgalactiae (Streptococcus dysgalactiae subsp. dysgalactiae).Other members of Streptococcusspecies that cause mild bovine mastitis are Streptococcus sanguis, Streptococcus salivariusand Streptococcus parauberis[75].

3.1.2 Escherichia coli

Mastitis is caused by multiple bacterial etiologies, where E. coliis known as one of the most significant causes of clinical mastitis in dairy animals, typically occurred in high producing cows as wells as cows in the early lactation period with low somatic cell counts [76]. Escherichia coli(E. coli) is a gram-negative environmental pathogen and is positive for catalase test and negative for coagulase test [77, 78]. Many animals are the carriers, but cattle are the main carriers of E. coli.Pathogenic strains of E. colican be differentiated from the strains of normal flora on the basis of the presence of virulence factors such as adhesin proteins, antibiotic resistance, and biofilm production [79, 80]. There are distinctive CITED2(Cbp/P300 Interacting Transactivator With Glu/Asp Rich Carboxy-Terminal Domain 2), SLC40A1(Solute Carrier Family 40 Member 1), and LGR4(Leucine Rich Repeat Containing G Protein-Coupled Receptor 4) genes specific to E. coliisolated from the bovine mastitis [81]. Moreover, E. coliisolates from bovine mastitis cases contain a variety of serogroups [82]. It has been reported that multiplication of E. colioccurs in mammary secretions without its adherence to mammary glands epithelium. A study on mastitis epidemiology has revealed that the severity of E. colimastitis is mainly linked with cow factors, as well as strain characteristics [83]. E. coliis the udder pathogen causing mastitis in dairy animals, and its endotoxin is potential health threat at consumer end [84]. Its long persistence and associated virulence factors are more often a point of concern in the dairy farm environment [85]. Toll-like receptor-4 has major role in the pathogenesis of E. coliin mastitis [86]. Cephalosporins and non-steriodal anti-inflammatory drugs are commonly recommended for the treatment of E. colimastitis, to which microbe has evolved the resistive character [84, 87]. The chronic nature of E. colimastitis deteriorates the milk quality without notice of handlers [22]. The prevalence of subclinical mastitis in different districts of province Punjab was reported to be 32% with E. colias second most common isolate from samples with incidence rate of 16.18% [88]. The E. coliisolation rate from subclinically infected cows was 13% with subclinical mastitis 36% [89]. 25% mastitis prevalence with E. coliisolation rate of 18.47% in dairy buffaloes was reported by [90].

3.1.3 Nocardia spp.

Mastitis caused by Nocardiaspp. is rare in cattle and presents as mastitis with extensive granulomatous udder lesions. Nocardia is gram-positive, aerobic bacteria with filamentous branches [91]. Nocardia is an ever-present environmental saprophyte with more than 30 identified species [92].

3.1.4 Bacillus spp.

Bacillus cereusand Bacillus subtilisare saprophytes and they are the only pathogens that can cause mastitis. These are responsible for acute hemorrhagic mastitis in cattle [15, 16, 93]. Bacillus cereuscases are usually linked with teat injury or surgical infection. Mastitis can also occur in cattle during calving and is linked with brewing grains mixed with Bacillus cereusspores. Several strains of the Bacillusspecies are non-pathogenic, and the isolated strains from clinically healthy bovine teat change rapidly over time [91].

3.1.5 Klebsiella species

Mastitis caused by Klebsiella pneumoniaecan be severe as it responds poorly to commonly used mastitis treatment protocols and rapid progression to toxic shock, resulting in death [94, 95]. Klebsiella pneumoniaeis still a challenge to dairy animals and causes udder infections even after the advancement in control of mastitis [96, 97]. Mastitis caused by K. pneumoniaetends to be prolonged and severe because of its low sensitivity to antibiotic treatment and can lead to animal death if left untreated. Klebsiellaspecies cause more losses to the dairy industry than E. coliin terms of mastitis [96].

3.1.6 Pseudomonas aeruginosa

Pseudomonas aeruginosais one of the causative agents of bovine mastitis [9899]. Most strains of Pseudomonas aeruginosahave a type III secretion system that can induce an increase in the number of somatic cells count in the mastitic milk. In addition, most Pseudomonas aeruginosastrains can form biofilms, reducing the effectiveness of antibiotics [100].

3.1.7 Other Pseudomonas species

Pseudomonasspecies are potential environmental pathogens, frequently associated with wet bedding and water used in milking parlor [98, 100]. Trauma to teat ends due to improper milking increases the chances of Pseudomonas aeruginosainfections. P. aeruginosais commonly isolated from mastitic animals and possesses different virulent factors like exo-enzyme, exotoxin A and protease that initiate an inflammatory response and cellular death [51, 101]. It can survive in different environmental conditions and infect susceptible cows through teat canal. Immuno-compromised cows, due to infectious diseases and nutritional deficiencies, are more susceptible to P. aeruginosainfection. This microorganism is reported as extremely resistant to commonly used antimicrobials [97]; therefore, adopting the hygienic practices, isolation, and culling of infected cows are the only available control measures [100].

3.2 Minor mastitis pathogens

Minor mastitis pathogens include a range of different environmental microorganisms including some non-aureus staphylococci and Corynebacteriumspecies. Some non-aureus staphylococci are opportunistic environmental bacteria that normally reside on the nasal tissue, teats, and hands of milking personnel [102]. Non-aureus staphylococci are considered as the emerging mastitis-causing bacterial pathogens [19, 103, 104]. Non-aureus staphylococci exhibit less pathogenicity as compared to other principal mastitis-causing pathogens and infections, most of the time remain subclinical. However, persistent non-aureus staphylococci infection can lead to reduced milk production and milk quality, increased somatic cell count, and severe damage to the udder [105]. Trueperella pyogenescauses summer mastitis and low-grade mastitis in the cows, often being clinically well but with a very enlarged and painful quarter [106]. Despite the high-frequency isolation, non-aureus staphylococci are considered minor mastitis pathogens but still a significant challenge for dairy farmers [12, 107].


4. Other mastitis pathogens

Some members of Enterococcusspecies like Enterococcus faecalis, Enterococcus saccharolyticusand Enterococcus faeciumcause bovine mastitis [75]. Moreover, Aerococcus viridanshas also been reported as a causative agent of mastitis, but its potential role has not been elucidated yet [108].


5. Conclusion

Mastitis is the most common and economically important disease for dairy industry, regarding milk quality and quantity. Microorganisms enter the udder and multiply in the glandular parenchyma, producing toxins that cause direct harm. Bovine mastitis is caused by a wide range of environmental and contagious pathogens. Contagious pathogens are those whose main reservoir is infected udder of an animal. The major contagious agents include Staphylococcus aureus, Streptococcus agalactiae, and Mycoplasmaspecies. On the other hand, environmental mastitis is caused by pathogens such as Escherichia coli, Streptococcus dysgalactiae, Streptococcus uberis, Trueperella pyogenes, Enterobacter aerogenes, Klebsiellaspecies, some yeast, fungi and Pseudomonasspecies. Mammary gland infections caused by these pathogens are of short duration and have severe clinical presentation. Environmental pathogens are usually linked with unsanitary managemental practices, resulting in the clinical symptoms (udder/quarter swelling, abnormal milk quality and quantity, and anorexia). Due to emerging concern of increasing antibiotic resistance, preventive strategies for controlling mastitis pathogens are needed. Control of significant risk factors, pasture management, optimal sanitary and feeding practices is a prime goal of such strategies. There are some mastitis vaccines against specific bacterial pathogen in the market that are reported to reduce the challenge, but unfortunately, none of them has provided promising results against all mastitis pathogens. Understanding the transmission pathways, better diagnostic tools and implementation of mastitis control program in efficient way can lead to drastically lessen the mastitis burden in dairy industry.


Conflict of interest

Authors declare no conflict of interest.


  1. 1.Rainard P, Riollet C. Innate immunity of the bovine mammary gland. Vet Res [Internet]. 2006 May;37(3):369-400. Available from:
  2. 2.Cañedo-Dorantes L, Cañedo-Ayala M. Skin Acute Wound Healing: A Comprehensive Review. Slomiany BL, editor. Int J Inflam [Internet]. 2019;2019:3706315. Available from:
  3. 3.Chaffer M, Leitner G, Glickman A, Creveld C van, Winkler M, Saran A, et al. Determination of udder health in camels (Camelus dromedarius). J Camel Pract Res. 2000;7(2):171-174.
  4. 4.Ranjan R, Swarup D, Patra RC, Nandi D. Bovine protothecal mastitis: A review. Vol. 1, CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources. 2006. p. 1-7.
  5. 5.Rollin E, Dhuyvetter KC, Overton MW. The cost of clinical mastitis in the first 30 days of lactation: An economic modeling tool. Prev Vet Med. 2015 Dec;122(3):257-264.
  6. 6.Raza A, Muhammad G, Sharif S, Atta A. Biofilm Producing Staphylococcus aureus and Bovine Mastitis: A Review. Mol Microbiol Res. 2013;3(1):1-8.
  7. 7.Raza A, Muhammad G, Sharif S, Atta A. Biofilm Producing Staphylococcus aureus and Bovine Mastitis: A Review. Mol Microbiol Res. 2013 Apr 10;33:1-8.
  8. 8.Naseer MA, Aqib AI, Ashar A, Saleem MI, Shoaib M, Kulyar MF-A, et al. Detection of Altered Pattern of Antibiogram and Biofilm Character in Staphylococcus aureus Isolated From Dairy Milk. Pakistan J Zool. 2021;53(1):191-199.
  9. 9.van den Brom R, de Jong A, van Engelen E, Heuvelink A, Vellema P. Zoonotic risks of pathogens from sheep and their milk borne transmission. Small Rumin Res [Internet]. 2020;106123. Available from:
  10. 10.Gruet P, Maincent P, Berthelot X, Kaltsatos V. Bovine mastitis and intramammary drug delivery: Review and perspectives. Vol. 50, Advanced Drug Delivery Reviews. 2001. p. 245-59.
  11. 11.Kheirabadi P, Ebrahimi A, Barati F. Prevalence, contagious pathogens and antibiotics susceptibilities of sub clinical bovine mastitis. Indian Vet J. 2008;85(4):375-377.
  12. 12.Hillerton JE, Berry EA. Treating mastitis in the cow - A tradition or an archaism. In: Journal of Applied Microbiology. 2005. p. 1250-5.
  13. 13.Wente N, Grieger AS, Klocke D, Paduch J-H, Zhang Y, Leimbach S, et al. Recurrent mastitis–persistent or new infections? Vet Microbiol [Internet]. 2020;244:108682. Available from:
  14. 14.Muir DD. Reviews of the progress of Dairy Science: Frozen concentrated milk. Vol. 51, Journal of Dairy Research. 1984. p. 649-64.
  15. 15.Contreras Bravo G, Rodríguez J. Mastitis: Comparative Etiology and Epidemiology. J Mammary Gland Biol Neoplasia. 2011 Sep 27;16:339-356.
  16. 16.Vakkamäki J, Taponen S, Heikkilä A-M, Pyörälä S. Bacteriological etiology and treatment of mastitis in Finnish dairy herds. Acta Vet Scand [Internet]. 2017 May 25;59(1):33. Available from:
  17. 17.Allore HG. A review of the incidence of mastitis in buffaloes and cattle. Pak Vet J. 1993;13:1.
  18. 18.MK H. Bovine Mastitis and Its Therapeutic Strategy Doing Antibiotic Sensitivity Test. Austin J Vet Sci Anim Husb. 2017;4(1):1-12.
  19. 19.Radostits OM, Gay CC, Hinchcliff KW, Constable PD. Veterinary Medicine E-Book: A textbook of the diseases of cattle, horses, sheep, pigs and goats. Elsevier Health Sciences; 2006.
  20. 20.Horpiencharoen W, Thongratsakul S, Poolkhet C. Risk factors of clinical mastitis and antimicrobial susceptibility test results of mastitis milk from dairy cattle in western Thailand: Bayesian network analysis. Prev Vet Med [Internet]. 2019;164:49-55. Available from:
  21. 21.Lafi SQ, Al-Rawashdeh OF, Ereifej KI, Hailat NQ. Incidence of clinical mastitis and prevalence of subclinical udder infections in Jordanian dairy cattle. Prev Vet Med. 1994;18(2):89-98.
  22. 22.Rahman MA, Bhuiyan M, KAMAL MM, Shamsuddin M. Prevalence and risk factors of mastitis in dairy cows. Bangladesh Vet. 2010;26.
  23. 23.Al-Dughaym AM, Fadlelmula A. Prevalence, etiology and its seasonal prevalence of clinical and subclinical camel mastitis in Saudi Arabia. Br J Appl Sci Technol. 2015;9(5):441-449.
  24. 24.USDA NAHMS. Antibiotic use on U.S. dairy operations, 2002 and 2007 [Internet]. APHIS Info Sheet, USDA. 2008. Available from:
  25. 25.Takahashi T, Satoh I, Kikuchi N. Phylogenetic relationships of 38 taxa of the genus Staphylococcus based on 16S rRNA gene sequence analysis. Int J Syst Bacteriol. 1999;49(2):725-728.
  26. 26.Fox LK, Hancock DD. Effect of Segregation on Prevention of Intramammary Infections by Staphylococcus aureus. J Dairy Sci. 1989;72(2):540-544.
  27. 27.Aqib AI. Dairy Staphylococcus aureus: Epidemiology, Drug Susceptibilities, Drug Modulation, and Preventive Measures. In: Ijaz M, editor. Rijeka: IntechOpen; 2019. p. Ch. 3. Available from:
  28. 28.Lakew M, Tolosa T, Tigre W. Prevalence and major bacterial causes of bovine mastitis in Asella, South Eastern Ethiopia. Trop Anim Health Prod [Internet]. 2009;41(7):1525. Available from:
  29. 29.Neave FK, Dodd FH, Kingwill RG, Westgarth DR. Control of Mastitis in the Dairy Herd by Hygiene and Management. J Dairy Sci. 1969;52(5):696-707.
  30. 30.Zadoks RN, Allore HG, Barkema HW, Sampimon OC, Wellenberg GJ, Gröhn YT, et al. Cow- and quarter-level risk factors for Streptococcus uberis and Staphylococcus aureus mastitis. J Dairy Sci. 2001;84(12):2649-2663.
  31. 31.Marques VF, Motta CC, Soares BD, Melo DA, Coelho SM, Coelho ID, et al. Biofilm production and beta-lactamic resistance in BrazilianStaphylococcus aureusisolates from bovine mastitis. Braz J Microbiol. 2016/12/04. 2017;48(1):118-24.
  32. 32.Mathur T, Singhal S, Khan S, Upadhyay DJ, Fatma T, Rattan A. Detection of biofilm formation among the clinical isolates of Staphylococci: an evaluation of three different screening methods. Indian J Med Microbiol. 2006/03/01. 2006;24(1):25-9.
  33. 33.Romero D, Aguilar C, Losick R, Kolter R. Amyloid fibers provide structural integrity to Bacillus subtilis biofilms. Proc Natl Acad Sci U S A [Internet]. 01/13. 2010;107(5):2230-4. Available from:
  34. 34.Cramer N, Klockgether J, Wrasman K, Schmidt M, Davenport CF, Tümmler B. Microevolution of the major common Pseudomonas aeruginosa clones C and PA14 in cystic fibrosis lungs. Environ Microbiol [Internet]. 2011;13(7):1690-1704. Available from:
  35. 35.Fox LK, Zadoks RN, Gaskins CT. Biofilm production by Staphylococcus aureus associated with intramammary infection. Vet Microbiol [Internet]. 2005;107(3):295-299. Available from:
  36. 36.Käppeli N, Morach M, Corti S, Eicher C, Stephan R, Johler S. Staphylococcus aureus related to bovine mastitis in Switzerland: Clonal diversity, virulence gene profiles, and antimicrobial resistance of isolates collected throughout 2017. J Dairy Sci [Internet]. 2019;102(4):3274-3281. Available from:
  37. 37.Yılmaz EŞ, Aslantaş Ö. Antimicrobial resistance and underlying mechanisms in Staphylococcus aureus isolates. Asian Pac J Trop Med [Internet]. 2017;10(11):1059-1064. Available from:
  38. 38.San Millan A, Escudero JA, Gifford DR, Mazel D, MacLean RC. Multicopy plasmids potentiate the evolution of antibiotic resistance in bacteria. Nat Ecol Evol [Internet]. 2016;1(1):10. Available from:
  39. 39.Chang VS, Dhaliwal DK, Raju L, Kowalski RP. Antibiotic Resistance in the Treatment of Staphylococcus aureus Keratitis: a 20-Year Review. Cornea [Internet]. 2015 Jun;34(6):698-703. Available from:
  40. 40.Dersch P, Khan MA, Mühlen S, Görke B. Roles of Regulatory RNAs for Antibiotic Resistance in Bacteria and Their Potential Value as Novel Drug Targets [Internet]. Vol. 8, Frontiers in Microbiology . 2017. p. 803. Available from:
  41. 41.Bolte J, Zhang Y, Wente N, Mahmmod YS, Svennesen L, Krömker V. Comparison of phenotypic and genotypic antimicrobial resistance patterns associated with Staphylococcus aureus mastitis in German and Danish dairy cows. J Dairy Sci [Internet]. 2020;103(4):3554-3564. Available from:
  42. 42.Yarwood JM, Bartels DJ, Volper EM, Greenberg EP. Quorum sensing in Staphylococcus aureus biofilms. J Bacteriol [Internet]. 2004;186(6):1838-50. Available from:
  43. 43.McCarthy AJ, Lindsay JA. Genetic variation in staphylococcus aureus surface and immune evasion genes is lineage associated: Implications for vaccine design and host-pathogen interactions. BMC Microbiol. 2010;10(1):173.
  44. 44.Brady RA, Leid JG, Camper AK, Costerton JW, Shirtliff ME. Identification of Staphylococcus aureus proteins recognized by the antibody-mediated immune response to a biofilm infection. Infect Immun. 2006;74(6):3415-3426.
  45. 45.Aydin A, Sudagidan M, Muratoglu K. Prevalence of staphylococcal enterotoxins, toxin genes and genetic-relatedness of foodborne Staphylococcus aureus strains isolated in the Marmara Region of Turkey. Int J Food Microbiol. 2011;148(2):99-106.
  46. 46.Abbas Ali B, Coleman G. The characteristics of extracellular protein secretion by Staphylococcus aureus (Wood 46) and their relationship to the regulation of α toxin formation. J Gen Microbiol. 1977;99(2):277-282.
  47. 47.Khoshnood S, Heidary M, Asadi A, Soleimani S, Motahar M, Savari M, et al. A review on mechanism of action, resistance, synergism, and clinical implications of mupirocin againstStaphylococcus aureus. Biomed Pharmaother [Internet]. 2019;109:1809-18. Available from:
  48. 48.Keefe G. Update on control ofstaphylococcus aureusandstreptococcus agalactiaefor management of mastitis. Vol. 28, Veterinary Clinics of North America - Food Animal Practice. 2012. p. 203-16.
  49. 49.Oliveira L, Hulland C, Ruegg PL. Characterization of clinical mastitis occurring in cows on 50 large dairy herds in Wisconsin. J Dairy Sci. 2013;96(12):7538-7549.
  50. 50.Oliveira CSF, Hogeveen H, Botelho AM, Maia P V, Coelho SG, Haddad JPA, et al. Quarter and cow risk factors associated with the occurrence of clinical mastitis in dairy cows in the United Kingdom. Prev Vet Med [Internet]. 2007;92(11):2551-61. Available from:
  51. 51.Mbindyo CM, Gitao GC, Mulei CM. Prevalence, Etiology, and Risk Factors of Mastitis in Dairy Cattle in Embu and Kajiado Counties, Kenya. Vet Med Int [Internet]. 2020 Aug 4;2020:8831172. Available from:
  52. 52.Reyes J, Chaffer M, Sanchez J, Torres G, Macias D, Jaramillo M, et al. Evaluation of the efficacy of intramuscular versus intramammary treatment of subclinical Streptococcus agalactiae mastitis in dairy cows in Colombia. J Dairy Sci. 2015;98(8):5294-5303.
  53. 53.Zadoks RN, Middleton JR, McDougall S, Katholm J, Schukken YH. Molecular epidemiology of mastitis pathogens of dairy cattle and comparative relevance to humans. J Mammary Gland Biol Neoplasia [Internet]. 2011/10/04. 2011 Dec;16(4):357-72. Available from:
  54. 54.Lyhs U, Kulkas L, Katholm J, Waller KP, Saha K, Tomusk RJ, et al. Streptococcus agalactiae serotype IV in humans and cattle, Northern Europe. Emerg Infect Dis. 2016;22(12):2097-2103.
  55. 55.Emaneini M, Khoramian B, Jabalameli F, Abani S, Dabiri H, Beigverdi R. Comparison of virulence factors and capsular types of Streptococcus agalactiae isolated from human and bovine infections. Microb Pathog. 2016;91:1-4.
  56. 56.Keefe GP, Dohoo IR, Spangler E. Herd Prevalence and Incidence of Streptococcus agalactiae in the Dairy Industry of Prince Edward Island. J Dairy Sci. 1997;80(3):464-470.
  57. 57.Hillerton JE, Berry EA. The management and treatment of environmental streptococcal mastitis. Vol. 19, Veterinary Clinics of North America - Food Animal Practice. 2003. p. 157-69.
  58. 58.Nicholas RAJ, Fox LK, Lysnyansky I. Mycoplasma mastitis in cattle: To cull or not to cull. Vol. 216, Veterinary Journal. 2016. p. 142-7.
  59. 59.Carrillo-Casas EM, Miranda-Morales RE. Bovine mastitis pathogens: prevalence and effects on somatic cell count. In: Milk Production-An Up-to-Date Overview of Animal Nutrition, Management and Health. IntechOpen; 2012.
  60. 60.Hirose K, Kawasaki Y, Kotani K, Tanaka A, Abiko K, Ogawa H. Detection of Mycoplasma in Mastitic Milk by PCR Analysis and Culture Method. J Vet Med Sci. 2001;63(6):691-693.
  61. 61.Fox LK, Hancock DD, Mickelson A, Britten A. Bulk tank milk analysis: Factors associated with appearance of Mycoplasma sp. in milk. J Vet Med Ser B. 2003;50(5):235-240.
  62. 62.Hertl JA, Schukken YH, Welcome FL, Tauer LW, Gröhn YT. Effects of pathogen-specific clinical mastitis on probability of conception in Holstein dairy cows. J Dairy Sci [Internet]. 2014;97(11):6942-6954. Available from:
  63. 63.Wenz JR, Barrington GM, Garry FB, McSweeney KD, Dinsmore RP, Goodell G, et al. Bacteremia associated with naturally occuring acute coliform mastitis in dairy cows. J Am Vet Med Assoc. 2001;219(7):976-981.
  64. 64.Blood DC (Douglas C. Veterinary medicine : a textbook of the diseases of cattle, sheep, pigs, goats and horses/by D.C. Blood, O.M. Radostits and J.A. Henderson ; with contributions by J.H. Arundel and C.C. Gay. Henderson JA (James A, Radostits OM, editors. London: Bailliere Tindall; 1983.
  65. 65.Paape M, Mehrzad J, Zhao X, Detilleux J, Burvenich C. Defense of the Bovine Mammary Gland by Polymorphonuclear Neutrophil Leukocytes. J Mammary Gland Biol Neoplasia [Internet]. 2002;7(2):109-21. Available from:
  66. 66.Aqib AI, Ijaz M, Farooqi SH, Ahmed R, Shoaib M, Ali MM, et al. Emerging discrepancies in conventional and molecular epidemiology of methicillin resistantStaphylococcus aureusisolated from bovine milk. Microb Pathog [Internet]. 2018;116:38-43. Available from:
  67. 67.Abdel-Rady A, Sayed M. Epidemiological Studies on Subclinical Mastitis in Dairy cows in Assiut Governorate. Vet World. 2009 Jan 1;2(10):373-380.
  68. 68.Messele YE, Abdi RD, Tegegne DT, Bora SK, Babura MD, Emeru BA, et al. Analysis of milk-derived isolates of E. coli indicating drug resistance in central Ethiopia. Trop Anim Health Prod. 2019;51(3):661-667.
  69. 69.Gomes F, Saavedra MJ, Henriques M. Bovine mastitis disease/pathogenicity: evidence of the potential role of microbial biofilms. Pathog Dis [Internet]. 2016 Apr 1;74(3). Available from:
  70. 70.Munita JM, Bayer AS, Arias CA. Evolving resistance among Gram-positive pathogens. Clin Infect Dis [Internet]. 2015 Sep 15;61 Suppl 2(Suppl 2):S48-57. Available from:
  71. 71.Klaas IC, Zadoks RN. An update on environmental mastitis: Challenging perceptions. Transbound Emerg Dis [Internet]. 2018 May 1;65(S1):166-85. Available from:
  72. 72.Petersson-Wolfe CS, Mullarky IK, Jones GM. Staphylococcus aureus mastitis: cause, detection, and control. Virginia Coop Ext. 2010;1:1-7.
  73. 73.Mcdougall S. Bovine mastitis: Epidemiology, treatment and control. N Z Vet J. 2002 Feb 1;50:81-84.
  74. 74.Olde Riekerink R, Kelton D, Scholl D. Incidence Rate of Clinical Mastitis on Canadian Dairy Farms. J Dairy Sci. 2008 May 1;91:1366-1377.
  75. 75.Østerås O, Sølverød L. Norwegian mastitis control programme. Ir Vet J. 2009 Apr 1;62 Suppl 4:S26-S33.
  76. 76.Ahmed HF, Straubinger RK, Hegazy YM, Ibrahim S. Subclinical mastitis in dairy cattle and buffaloes among small holders in Egypt: Prevalence and evidence of virulence of escherichia coli causative agent. Trop Biomed. 2018;35(2):321-329.
  77. 77.Bergey DH, Holt JG. Bergey’s manual of determinative bacteriology. 1994.
  78. 78.Anwar MA, Aqib AI, Ashfaq K, Deeba F, Khan MK, Khan SR, et al. Antimicrobial resistance modulation of MDRE. coliby antibiotic coated ZnO nanoparticles. Microb Pathog [Internet]. 2020;148:104450. Available from:
  79. 79.Srinivasan V, Gillespie BE, Lewis MJ, Nguyen LT, Headrick SI, Schukken YH, et al. Phenotypic and genotypic antimicrobial resistance patterns of Escherichia coli isolated from dairy cows with mastitis. Vet Microbiol. 2007;124(3-4):319-328.
  80. 80.Dogan B, Klaessig S, Rishniw M, Almeida RA, Oliver SP, Simpson K, et al. Adherent and invasive Escherichia coli are associated with persistent bovine mastitis. Vet Microbiol [Internet]. 2006;116(4):270-282. Available from:
  81. 81.Ju Z, Jiang Q, Wang J, Wang X, Yang C, Sun Y, et al. Genome-wide methylation and transcriptome of blood neutrophils reveal the roles of DNA methylation in affecting transcription of protein-coding genes and miRNAs in E. coli-infected mastitis cows. BMC Genomics [Internet]. 2020;21(1):102. Available from:
  82. 82.Wenz JR, Barrington GM, Garry FB, Ellis RP, Magnuson RJ. Escherichia coli isolates’ serotypes, genotypes, and virulence genes and clinical coliform mastitis severity. J Dairy Sci. 2006;89(9):3408-3412.
  83. 83.Güler L, Gündüz K. Virulence properties of Escherichia coli isolated from clinical bovine mastitis. Turkish J Vet Anim Sci. 2007;31(5):361-365.
  84. 84.Liu G, Ding L, Han B, Piepers S, Naqvi SA, Barkema HW, et al. Characteristics ofEscherichia coliIsolated from Bovine Mastitis Exposed to Subminimum Inhibitory Concentrations of Cefalotin or Ceftazidime. Laranjo M, editor. Biomed Res Int. 2018;2018:4301628.
  85. 85.Bicalho RC, Santos TMA, Gilbert RO, Caixeta LS, Teixeira LM, Bicalho MLS, et al. Susceptibility ofEscherichia coliisolated from uteri of postpartum dairy cows to antibiotic and environmental bacteriophages. Part I: Isolation and lytic activity estimation of bacteriophages. J Dairy Sci. 2010;
  86. 86.De Schepper S, De Ketelaere A, Bannerman D. D, Paape J. M, Peelman L, Burvenich C. The toll-like receptor-4 (TLR-4) pathway and its possible role in the pathogenesis ofEscherichia colimastitis in dairy cattle. Vet Res [Internet]. 2008 Jan;39(1). Available from:
  87. 87.Yeiser EE, Leslie KE, McGilliard ML, Petersson-Wolfe CS. The effects of experimentally induced Escherichia coli mastitis and flunixin meglumine administration on activity measures, feed intake, and milk parameters. J Dairy Sci [Internet]. 2012;95(9):4939-4949. Available from:
  88. 88.Ali MA, Ahmad MD, Muhammad K, Anjum AA, others. Prevalence of sub clinical mastitis in dairy buffaloes of Punjab, Pakistan. Okara. 2011;150(63):42.
  90. 90.Lamey AE, Ammar AM, Zaki ER, Khairy N, Moshref BS, Refai MK. Virulence factors of Escherichia coli isolated from recurrent cases of clinical and subclinical mastitis in buffaloes. Intl J. 2013;4(1):86-94.
  91. 91.Al-Qumber M, Tagg JR. Commensal bacilli inhibitory to mastitis pathogens isolated from the udder microbiota of healthy cows. J Appl Microbiol. 2006;101(5):1152-1160.
  92. 92.Osman KM, El-Enbaawy MI, Ezzeldin NA, Hussein HMG. Nitric oxide and lysozyme production as an impact to Clostridium perfringens mastitis. Comp Immunol Microbiol Infect Dis. 2010;33(6):505-511.
  93. 93.Redeat B, Belihu K, Asamenew T. Microbiological study on bacterial causes of bovine mastitis and its antibiotics suscebtibility patterns in East Showa Zone, Akaki District, Ethiopia. J Vet Med Anim Heal. 2014 Apr 30;6:116-122.
  94. 94.Alonso VPP, Queiroz MM, Gualberto ML, Nascimento MS. Klebsiella pneumonia carbapenemase (KPC), methicillin-resistantStaphylococcus aureus(MRSA), and vancomycin-resistant Enterococcus spp. (VRE) in the food production chain and biofilm formation on abiotic surfaces. Curr Opin Food Sci [Internet]. 2019;26:79-86. Available from:
  95. 95.Ericsson Unnerstad H, Lindberg A, Persson Waller K, Ekman T, Artursson K, Nilsson-Öst M, et al. Microbial aetiology of acute clinical mastitis and agent-specific risk factors. Vet Microbiol [Internet]. 2009;137(1):90-97. Available from:
  96. 96.Paulin-Curlee GG, Sreevatsan S, Singer RS, Isaacson R, Reneau J, Bey R, et al. Molecular subtyping of mastitis-associated klebsiella pneumoniae isolates shows high levels of diversity within and between dairy herds. J Dairy Sci. 2008;91(2):554-563.
  97. 97.Suleiman TS, Karimuribo ED, Mdegela RH. Prevalence of bovine subclinical mastitis and antibiotic susceptibility patterns of major mastitis pathogens isolated in Unguja island of Zanzibar, Tanzania. Trop Anim Health Prod [Internet]. 2018;50(2):259-66. Available from:
  98. 98.Sumon SMMR, Ehsan MA, Islam MT. Subclinical mastitis in dairy cows: somatic cell counts and associated bacteria in Mymensingh, Bangladesh. J Bangladesh Agric Univ. 2017 Dec 29;15:266.
  99. 99.Blood DC, Radostits OM, Arundel JH, Gay CC. Veterinary medicine: a textbook of the diseases of catlle, sheep, pigs, goats and horses. 1989;
  100. 100.Park H, Hong M, Hwang S, Park Y, Kwon K, Yoon J, et al. Characterisation of Pseudomonas aeruginosa related to bovine mastitis. Acta Vet Hung. 2014;62(1):1-12.
  101. 101.Najeeb M, Anjum A, Ahmad M-D, Khan H, Ali M, Sattar MMK. Bacterial etiology of subclinical mastitis in dairy goats and multiple drug resistance of the isolates. J Anim Plant Sci. 2013 Nov 25;23:1541-1544.
  102. 102.El-Jakee JK, Aref NE, Gomaa A, El-Hariri MD, Galal HM, Omar SA, et al. Emerging of coagulase negative staphylococci as a cause of mastitis in dairy animals: An environmental hazard. Int J Vet Sci Med. 2013;1(2):74-78.
  103. 103.Qu Y, Zhao H, Nobrega DB, Cobo ER, Han B, Zhao Z, et al. Molecular epidemiology and distribution of antimicrobial resistance genes of Staphylococcus species isolated from Chinese dairy cows with clinical mastitis. J Dairy Sci [Internet]. 2019;102(2):1571-1583. Available from:
  104. 104.Amer S, Gálvez FLA, Fukuda Y, Tada C, Jimenez IL, Valle WFM, et al. Prevalence and etiology of mastitis in dairy cattle in El Oro Province, Ecuador. J Vet Med Sci [Internet]. 2018/04/10. 2018 Jun 6;80(6):861-8. Available from:
  105. 105.Pyörälä S, Taponen S. Coagulase-negative staphylococci-Emerging mastitis pathogens. Vet Microbiol. 2009;134(1-2):3-8.
  106. 106.Kibebew K. Bovine Mastitis : A Review of Causes and Epidemiological Point of View. J Biol Agric Healthc [Internet]. 2017;7(2):1-14. Available
  107. 107.Barkema HW, Green MJ, Bradley AJ, Zadoks RN. Invited review: The role of contagious disease in udder health. Vol. 92, Journal of Dairy Science. Elsevier; 2009. p. 4717-4729.
  108. 108.Song X, Huang X, Xu H, Zhang C, Chen S, Liu F, et al. The prevalence of pathogens causing bovine mastitis and their associated risk factors in 15 large dairy farms in China: an observational study. Vet Microbiol [Internet]. 2020;108757. Available from:

Written By

Muhammad Shoaib, Amjad Islam Aqib, Muhammad Aamir Naseer, Zeeshan Ahmad Bhutta, Wanxia PU, Qaisar Tanveer, Iqra Muzammil, Muhammad Fakhar-e-Alam Kulyar, Muhammad Salman Younas and Muhammad Hammad

Submitted: December 6th, 2020Reviewed: May 24th, 2021Published: August 17th, 2021