Abstracting and Indexing

  • Google Scholar
  • CrossRef
  • WorldCat
  • ResearchGate
  • Academic Keys
  • DRJI
  • Microsoft Academic
  • Academia.edu
  • OpenAIRE

Bovine Mastitis in Oman is Mainly Associated with Environmental Bacteria that Show High Resistance to Commonly Used Antibiotics

Article Information

Al-Haddadi W1, Elshafie A2, Al-Ansari A3, Al-Mawly J1, Al-Hatali R1, Al-Habsi H1, Al-Hshami A1, Al-Ansari A2,*

1Bacteriology laboratory, Central laboratory of Animal Health, Animal Wealth General Directorate, Ministry of Agriculture and Fisheries, Oman

2Department of Biology, College of Science, Sultan Qaboos University, Al-Khoud, Oman

3Department of Animal and Veterinary Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Oman

*Corresponding Author: Aliya Al-Ansari, Department of Biology, College of Science, Sultan Qaboos University, Al-Khoud, Oman;

Received: 17 March 2020; Accepted: 29 March 2020; Published: 06 April 2020

Citation: Al-Haddadi W, Elshafie A, Al-Ansari A, Al-Mawly J, Al-Hatali R, Al-Habsi H, Al-Hshami A, Al-Ansari A. Bovine Mastitis in Oman is Mainly Associated with Environmental Bacteria that Show High Resistance to Commonly Used Antibiotics. Archives of Microbiology & Immunology 4 (2020): 38-50.

View / Download Pdf Share at Facebook

Abstract

In Oman, mastitis is an important disease that affects the dairy animals, especially cows. In this study, bacteria and fungi from subclinical and clinical mastitis were identified using 16S rDNA and 18S rDNA, respectively, in 76 milk samples from 30 cows. The frequency of subclinical mastitis (75%) was higher than clinical mastitis (25%). Bacterial isolates were detected in 82% of the samples, out of which 12% showed mixed bacterial cultures. The most predominant isolated bacteria were environmental bacteria rather than minor and contagious bacteria from subclinical (53.6%, 42.8% and 3.6%, respectively) and clinical mastitis (62.5%, 25% and 12.5%, respectively).

Antibiotic resistance profiles of the isolated bacteria for six commonly used antibiotics showed an increase in resistance compared to a previous study in 1991. Most isolated bacteria were resistance to AMP, while they were more sensitive for SXT and TE. Eleven percent of the isolated bacteria were resistance to four of the antibiotics tested or more.

About half of the samples (47%) were positive for fungal growth. Most of those samples were positive for bacteria, which suggested that detected fungi may be opportunistic. However, 3% of the investigated samples were negative for bacterial growth, which may indicate pathogenic involvement in mastitis.

In conclusion, the major association of mastitis with environmental bacteria and the detected multi-antibiotics resistance emphasized the need for using appropriate control protocols by allowing to investigate each case and determine whether antibiotic treatment is necessary and which antibiotics to be used.

Keywords

Mastitis; Oman; Antibiotics resistance; Contiguous pathogens; Environmental pathogens; Fungi; Minor pathogens

Mastitis articles, Oman articles, Antibiotics resistance articles, Contiguous pathogens articles, Environmental pathogens articles, Fungi articles, Minor pathogens articles

Article Details

Abbreviations

PCR          Polymerase chain reaction

ITS            Internal transcribed spacer

EF             Elongation factor

MWT        Modified White Side Test

SCC          Somatic cell count

CM           Clinical mastitis

SCM         Subclinical mastitis

AMP         Ampicillin

AML        Amoxicillin

SXT         Trimethoprim-sulfamethoxazole

GE           Gentamicin

TE            Tetracycline

S               Streptomycin

NCBI  National Center for Biotechnology    Information

BOLD       Barcode of Life Data System

AST          Antibiotic Susceptibility Testing

CNS         Coagulase Negative Staphylococci

CPS          Coagulase Positive Staphylococci

GNB         Gram Negative Bacteria

Introduction

Mastitis is an important, complex and multifactorial disease. It is the most common and costliest disease affecting dairy farms in the western world (Barkema et al., 2009; Gelasakis et al., 2015). It affects the udder of dairy animals causing several changes to milk and udder. These changes can be chemical, physical and pathological in the glandular tissues (Sukumar and James, 2012). It may result from the interaction of host, pathogen(s) and environmental factors (Sharif et al., 2009; Rofaida, 2010).

According to the pathogens associated, transmission mode and primary reservoir, mastitis is classified into contagious and environmental mastitis (Makovec and Ruegg, 2003). Contagious pathogens are pathogens that live in the mammary glands of the host and are able to cause subclinical infection. They are transmitted during milking from cow to cow through the hands of the milking person, milking machine or udder cloths (Blowey and Edmondson, 2010). Environmental pathogens are opportunistic pathogens that live in cow environment (Kivaria, 2006). They can enter and attack the udder after milking (Blowey and Edmondson, 2010).

Different species of bacteria are associated with mastitis in different geographical areas due to variation in the management practiced in the different countries (Ahmed et al., 2016). Mastitis caused by bacteria represents a major risk for human health, as pathogenic bacteria and their toxins increase the chance of foodborne diseases (Ikiz et al., 2013; Bhatt et al., 2011; Sharma et al., 2011). Many mastitis bacteria are responsible for several diseases in human such as tuberculosis, streptococcal intoxication, colibacillosis, streptococcal sore throat, and brucellosis (Tesfaheywet and Gerema 2017).

Overuse of antibiotics for mastitis treatment or for protection during the dry periods was associated with the development of antibiotic resistant strains of bacteria (Bradley, 2002) and also, the increase of mastitis incidence caused by yeast (Erbaş et al., 2017; Wawron et al., 2010). Fungal infections are associated with additional factors including the lack of hygiene, high humidity, high temperature, wet teat and when animal barn is crowded (TalebkhanGaroussi et al., 2009; Pachauri et al., 2013; Lagneau et al., 1996).

From several dairy farms in Oman, staphylococcus aureus reported to be the predominant causal pathogens of clinical mastitis in dairy cattle, cow, goats and sheep (Harby et al., 1991). Also, other bacteria were reported by theses authors to be Streptococcus dysgalactiae, Streptococcus galactiae, Streptococcus uberis, Escherichia coli, Klebsiella spp, Micrococcus, Enterbacter aerogenesand Corynebacterium pyogenes. Notably, sensitivity to 14 commonly used antibiotic were evaluated in the same study.

To the best of our knowledge, there were no studies on mastitis in Oman since 1991, except reports from the central lab of animal health, which identified the pathogens using culture method and the vitecx machine (2016 and 2017). Identified species were Staphylococcus spp, Coliform mastitis, Pseudomonas luteola, Enterobacte raerogenes, Enterobacterspp, Streptococcus uberis, Enterococcus faecalis, Proteus mirabilis, Klebsiella pneumonia spp, Salmonella enteric, Bacillus spp, Staphylococcus mastitis, coliform and Escherichia coli.

Thus, this study aimed to identify the major microorganisms associated with bovine mastitis cases in Oman including bacterial and mycotic pathogens by sequencing and to evaluate the sensitivity of pathogens being isolated to the commonly used antibiotics.

Materials and Methods

Sampling of milk

five to 15 ml Milk samples were obtained from 30 cows suspected to have clinical or subclinical mastitis during an eight months period (6/2017-1/2018). Samples of milk obtained from eight healthy animals (from the animal research centre Al-Rumais, MoAF) were used as controls. All animals were hand milked by veterinary technicians and veterinarians in veterinary clinics after disinfecting the teats with 70% alcohol and discarding the first streams of milk. five to 15ml of milk were taken into sterile vials and were labelled as from which quarter they were taken. The samples were transported in a cool box with ice packs to the bacteriology laboratory at the central laboratory of animal health. At the laboratory, the samples were kept at 4°C until used.

Laboratory analysis of milk

Consistency and colour evaluations were carried out according to Quinn et al., (1994). The milk samples were checked for colour change and the presence of blood, clots or flakes.

The pH of the milk samples were checked using pH test strips.

Modified White Side Test (MWT)

The test was performed as described by Kahir et al., 2008. Briefly, 100 µL of sodium hydroxide solution 4% was added to 250 µL of cold milk on slide on black background and then stirring the mixture vigorously for 20 seconds. The milk of normal quarter will have no reaction with addition of sodium hydroxide solution and remains uniformly opaque. While the milk of cow suffering from mastitis shows reaction with addition of sodium hydroxide solution.

The reaction was scored as follow:

Negative(N): opaque, milky mixture, no precipitant

 (+): Clumping of slight degree is present

(++): Mixture thickness, coagulated materials are present

(+++): Large mass of precipitants

Culturing of bacteria and fungi

For bacteria, the milk samples were cultured in nutrient broth for 1 day at 37°C. Then, the samples were cultured in nutrient agar and were examined for bacterial growth after 24 hours according to (Demme and Abegaz, 2015). The pure cultures were subjected to Gram staining according to manufacture protocol (TCS biosciences, UK). For fungi, the milk samples were cultured in Potato Dextrose Agar and were incubated at 37°C and examined for growth after 2 weeks according to (Pachauri et al., 2013; Sukumar and James, 2012).

DNA based identification

Genomic DNA was extracted from all isolated bacteria using High Pure PCR Template Preparation Kit (ROCH). Fungi were isolated using Power Soil DNA kit (MO BIO). The extracted DNA from bacteria and fungi were quantified using NanoDrop spectrophotometer (Thermo Scientific, Germany) at wavelength of 260/280 nm and checked on 1% agarose gel stained with ethidium bromide. Then, the 16S rDNA gene fragment was amplified using two universal primers (27F , 1492R) (Miller et al, 2013). The polymerase chain reaction (PCR) mixture consisted of 12.5µL of master mix (Thermo Scientific), 11.3µL of nuclease free water, 0.1µL of each primer, 1-2µL of DNA template. The PCR reaction was performed in 25µL volumes and three stages for 35 cycles. The first stage consisted of five cycle was initiated with 5 min at 94°C, followed by denaturation for 30 seconds at 94°C, and annealing for 30 seconds at 60°C. The extension was carried out for 2minutes at 72°C. The second stage consisted of five cycle started with denaturation for 30 seconds at 94°C, annealing for 30 seconds at 55°C and extension for 4 minutes at 72°C. The last stage consisted of 25cycles initiated with denaturation for 30 seconds at 94°C, annealing for 30 seconds at 50°C and extension for 4 minutes at 72°C. Additional extension step was carried out for 2 minutes at 72°C.

The internal transcription spacer (ITS) region and elongation factor (EF) gene fragments were amplified using ITS1 and ITS4primers (White et al., 1990), and EF4 and fung5primers (Smit et al, 1999), respectively. The PCR mixture consisted of 12.5µL of master mix (Thermo Scientific), 11.3µL of nuclease free water, 0.1µL of each primer, 1-2µL of DNA template. The PCR reaction was performed in 25-26µL volumes started with 10 min at 95°C. The 35 cycles initiated with denaturation for 1 min at 95°C, followed by annealing for 5 min at 55°C. The extension was carried out for 2 minutes at 72°C. Additional extension step was carried out for 10 minutes at 72°C.

The PCR products was purified using DyeEx Spin kit (QIAGEN) following the manufacturer’s protocol. The sequencing reaction was carried using Big Dye Terminator v3.1 Cycle Sequencing Big dye kit (Applied Biosystems, USA). The sequencing reaction product was purified in 96-Well Plates using sodium acetate purification. The purified DNA was sequenced using the genetic analyzer (3130 XL, Applied Biosystems, USA).

The sequencing results were edited using Bioedit software. The edited results were searched against the sequences available in National Centre for Biotechnology Information (NCBI) database and The Barcode of Life Data System (BOLD) database.

Antibiotic susceptibility testing(AST)

Antibiotic sensitivity tests was determined using disc diffusion method to each isolated strain. Mueller-Hinton agar medium and an antibiotic disc dispenser were used. Individual colonies were dipped in nutrient broth and then they were spread evenly on petri dishes contain the medium. A total of 6 antibiotic discs were tested against each strain and these were: Gentamicin (GE) (10µg), Amoxicillin/clavulanic acid (AML) (30 µg), Ampicillin/sulbactam (AMP) (10µg), Co-trimoxazole (SXT) (25µg), Streptomycin (S) (10 µg), Tetracycline (TE) (10 µg). The plates were incubated for 24 h and zone of inhibition were measured in mm according to (Bauer et al., 1966; Bhat et al., 2017). The zones of inhibition (mm) were compared to the standards of the antibiotic supplier and the tested strains were recorded as sensitive, intermediate or resistant.

Results and Discussion

Results showed that subclinical mastitis (75%) is more common in the investigated samples than clinical mastitis (Table 1), which is similar to which reported by other studies (Türkyilmaz et al., 2010; Abera et al., 2012). The increase in subclinical cases since 1991 could be attributed to increased awareness among farmers about milk characteristics from infected animals (i.e. reduction in quality and quantity of milk and complaints from consumers).

Subclinical

Clinical

Study

75%

25%

Oman 2018

89%

11%

Türkyilmaz et al., 2010

77%

23%

Abera et al., 2012

Table1: The Frequency of Clinical and Subclinical Mastitis in this study compared to other studies

The majority of mastitis cases were associated with environmental and minor pathogens (89% clinical and 96% subclinical) than contagious pathogens (11% clinical and 4% of subclinical) (Table 2). Notably, there is a clear increase in the association of environmental and minor bacteria (50.5% to 89%) and a decrease in contagious pathogens (49.5% to 11%), compared to what was reported earlier by Harby et al. (1991). However, the same was reported by others (Kivaria and Noordhuizen 2007 and Carrillo-Casas and Miranda-Morales, 2012).

Clinical

Subclinical

1991

2018

1991

2018

Environmental and minor bacteria

50.5%

89%

NA

96%

Contagious

49.5%

11%

NA

4%

Table 2: The frequencies of Environmental, minor and contagious bacteria in the clinical and subclinical mastitis

Staphylococcus aureus was the only identified contagious bacteria, while coagulase negative staphylococci (CNS), which is considered minor pathogens, was the most isolated microbes from clinical (24%) and subclinical (43%) cases (Table 3). In the earlier study, Staphylococcus aureus and Streptococcus agalactiae were reported (Harby et al., 1991) but many recent studies found that both contagious pathogens decreased, while CNS and Corynebacterium bovis are becoming more common (Pitkälä et al., 2004). In fact, CNS are emerging as common pathogens associated with mastitis (Zeryehun and Abera 2017; Adwan et al. 2015).

Minor

Contagious

Environmental

 

**Staphylococcus xylosus (5)

**Staphylococcus succinus (1)

**Staphylococcus chromogenes (4)

**Staphylococcus sciuri (9)

**Staphylococcus saprophyticus (5)

**Staphylococcus epidermidis (1)

***Staphylococcus agnetis (1)

***Staphylococcus hyicus (1)

Macrococcus caseolyticus (1)

Staphylococcus aureus (4)

 Achromobacter insolitus (1) *

Bacillus velezensis (1)*

Bacillus australimaris (2)*

Bacillus licheniformis (2)

Bacillus cereus (1)

Bacillus xiamenensis (1)*

Bacillus methylotrophicus (1)

Bacillus aryabhattai (1) *

Brevibacillu sborstelensis (1)*

Brevibacillus agri (2)*

Chryseobacterium indologenes (1)

Cosenzaea myxofaciens (1)*

Enterobacter cloacae (1)

Enterococcus faecium (1)

Enterococcus faecalis (1)

Enterococcus lactis (1)

Escherichia fergusonii (4)

Klebsiella pneumonia (3)

Lactococcus lactis (1)

Pantoea agglomerans (1)

Proteus mirabilis (5)

Providencia rettgeri (1)*

Pseudomonas aeruginosa (3)

Pseudomonas alcaligenes (1)

Shigella dysenteria (1)

Table 3: The number of identified contagious, environmental and minor bacteria

The classification of contagious and environmental pathogens according to Coulona, 2002.

*first record of mastitis association

**Coagulase-negative species; ***coagulase-positive and coagulase-variable species (based on Becker et al, 2014)

Coagulase positive: Staphylococcus xylosus, Staphylococcus saprophyticus, Staphylococcus aureus

It is worth highlighting that different species were associated with the environmental cases, nine of which were not previously associated with mastitis. However, some of these bacteria were reported in other studies and had been isolated from clinical and subclinical mastitis (Salih, 2013; Olivares-Pérez et al.,2015; Banerjee et al., 2017; Srednik et al., 2017; Munoz et al., 2007; or considered as potential pathogens in different diseases (Li et al., 2017).

The increase in percentage and diversity of environmental and minor bacteria as a cause of mastitis in Oman could be attributed to the resolution power of sequencing in the identification at the species level compared to the culture-based methods, the unhygienic milking procedures and poor housing practices and/or over use of antibiotics as discussed later. Fortunately, mastitis caused by environmental pathogens can be controlled by increasing the hygiene of environment and pre-dipping (Blowey and Edmondson, 2010) and therefore, cutting cost.

In this study, 18% of the samples were culture negative for bacteria. Although the percentage we are reporting is less than others (49.7%) (Makovec and Ruegg, 2003) these cases are of big concern in management. They could be due to anaerobic bacteria (Du Preez, 1989), algae (Ranjan et al.,2006), or mycoplasma infections and/or environmental factors like trauma and drought (Kuehn et al., 2013).

Almost half of the examined samples (47%) with mastitis were positive for fungal growth. Different types of fungi were detected in the subclinical (33%) and clinical mastitis milk samples (16 %) (Table 4). Fungi were isolated either mixed with bacteria (45%) or in pure cultures (3%). High frequency of mixed infection is comparable to what Dworecka-Kaszak et al. (2012) recorded (57%).

Clinical

Subclinical

Pichia manshurica

2

Cyberlindnera jadinii

1

Clavispora lusitaniae

1

Clavispora lusitaniae

3

Saccharomycopsis fibuligera

1

Aspergillus spp (A. tubingensis (2), oryzae(1),   flavus (1)

4

Talaromyces primulinus

1

Talaromyces pinophilus,

5

Pichia

kudriavzevii

1

Pichia manshurica

1

Aspergillus flavus

1

Saccharomycopsis capsularis

1

Candida glabrata

1

Pichia kudriavzevii

1

 

Galactomyces geotrichum

1

 

Geotrichum vulgare

2

Table 4: The number of identified fungal species associated with clinical and subclinical mastitis

Candida found to be the most predominant fungi in clinical and subclinical mastitis (66%), followed by Penicillium spp (28%), Aspergillus spp (16%), and Galactomyces geotrichum (12%). This is comparable with what was reported by others (Krukowski and Saba 2003; Kumar et al., 2016; Pachauri et al., 2013; Erbaşet al., 2017; Wawron et al., 2010; Krukowskiet al. 2001).

The negative bacterial cultures that were positive for fungi (3%) were associated with Candida glabrataand Aspergillus ustus. Notably, one of the isolated fungi was Geotrichum candidum, which is an opportunistic, keratinophilic yeast-like growth. Few reports around the world reported its involvement in mastitis and reported the genues (Costa et al.,1993).

Fungi are opportunistic organisms that are considered as normal flora in the udder skin and soil but are able to establish disease when immune system is weak (dos Santos and Marin, 2005). Weakness of the cow immune system may result from several factors like; changeable weather, mineral-vitamin deficiencies and antioxidant deficiencies (Wawron et al., 2010). Relatively high isolation of fungi from mastitis cases suggested potential unhygienic conditions and poor management practices to be associated. Moreover, fungal association can be attributed to prolong treatment with antibiotics (Pachauri et al., 2013). In fact, large doses of antibiotic without bacteriological examination cause vitamin A deficiency that damage the udder’s epithelium and teat injuries can facilitate infection by yeast (Krukowski et al., 2001).

Seven antibiotics that are commonly prescribed were used to evaluate the antibiotics sensitivity of the isolated bacteria; including Ampicillin/sulbactam, Amoxicillin/clavulanic acid, Gentamicin, Streptomycin, Co-trimoxazole and Tetracycline (Table 5). Notably, S. aureus isolates from different regions showed different resistance to different antibiotics. However, they all showed sensitivity for AML.

Bacteria isolates

AMP

AML

CN

SXT

S

TE

Escherichia fergusonii

25%

 

75%

75%

0%

25%

Klebsiella pneumoniae

0%

0%

33%

33%

0%

100%

Proteus mirabilis

20%

20%

100%

80%

40%

80%

Pseudomonas aeruginosa

33%

33%

100%

66%

66%

66%

Staphylococcus sciuri

0%

22%

67%

67%

 

100%

Staphylococcus chromogenes

0%

50%

50%

25%

 

50%

Staphylococcus saprophyticus

0

50%

80%

100%

 

100%

Staphylococcus aureus

25%

100%

75%

50%

 

50%

Staphylococcus xylosus

40%

50%

100%

100%

 

100%

Brevibacillusagri

0%

 

0%

100%

0%

 

Bacillus australimaris

50%

100%

0%

100%

100%

50%

Bacillus licheniformis

0%

0%

50%

50%

0%

0%

Table 5: Frequency of antibiotics sensitivity (Number of sensitive isolates /total isolates) for Bacteria isolates

Sensitivity: Number of isolates sensitive to antibiotic total isolates

Although, CNS show different antibiotics resistance patterns, generally their response to treatment is higher than treating mastitis caused by S. aureus (Taponen and Pyörälä, 2009). CNS exhibited a high degree of resistance to AMP and AML (92%, 67%respectively), while showed high sensitivity to CN (69%), SXT (69%) and TE (84%). Notably, most of the CNS isolates (77%) were resistant to more than one antibiotic. Our results is consistent with what was reported earlier by other (Gentilini et al., 2002; Mahami et al., 2011; Bansal et al., 2015; Beyene et al., 2017; Sumathi et al., 2008).

In this study, variety of Gram negative bacteria (GNB) were isolated from clinical and subclinical mastitis. GNB showed resistance to S (60%) and AMP (60%) and AML (52%) and sensitivity to SXT (64%), CN (60%) and TE (62%). Similar findings were observed by Nam et al. (2009) but a significant number of GNB isolates (72%) in this study had resistance to more than one antimicrobial, which is higher (35%) than what was reported earlier (Younis et al. 2017).

Compared to the study by Harby et al. (1991), it was noted that the patterns of bacterial sensitivity of Klebsiella spp and Staph. aureus to CN, TE and AMP had changed towards increased resistance to the tested antibiotics. The development of resistance strains to some antibiotic can be due to overuse in the farm as reported by many (Kumar et al., 2010; Bhatt et al., 2011; Sharma et al., 2007; Argaw, 2016; Ventola, 2015).

The main challenges faced with the emergence of antibiotic resistance are difficulty of treatment, severity of infection and increase of mortality rates (Abdel-Rady and Sayed, 2009). Moreover, the bacteria and their genes can be transmitted to humans through consumption of non-pasteurized milk, wild animals, contaminated waterways and food chain (Abdel-Rady and Sayed,2009; Manie et al.,1999).

Variations in antibiotic sensitivity profiles of some species was detected, and this was reported by others and attributed to differences in the use of antimicrobials (Sadashiv and Kaliwal, 2014; Kalińska et al., 2017). Staphylococcus agnetis, which is a coagulase-positive and isolated from clinical cases, showed resistance to all antibiotics used. Different studies reported different resistance to antibiotics (León  et al., 2015;Taponen et al., 2012).

Conclusion

Although mixed infections suggested to be treated with broad spectrum antibiotics,  what we found recommends informed antibiotic selection to intervene with the emergence of resistant bacteria. In addition, to minimize antimicrobial resistance, the use of antibiotics in animal health should be optimized and the nontherapeutic use of antimicrobials as growth promoters in agriculture should be limited.

Acknowledgment

The authors would like to extend their thanks to the staff in the Biology department, and the CAAR Unit in the college of Science, the Biochemistry laboratory in college of Medicine, and the central laboratory of Animal Health, Ministry of Agriculture and fisheries, Oman.

Conflicts of interest

The authors declare that they have no conflict of interest.

References

  1. Abdel-Rady A, Sayed M. Epidemiological Studies on Subclinical Mastitis in Dairy cows in Assiut Governorate. Veterinary world 2 (2009).
  2. Abera M, Habte T, Aragaw K, et al. Major causes of mastitis and associated risk factors in smallholder dairy farms in and around Hawassa, Southern Ethiopia. Tropical animal health and production 44 (2012): 1175-1179.
  3. Adwan G, Safieh DI, Aref R, et al. Prevalence of microorganisms associated with intramammary infection in cows and small ruminants in the North of Palestine. IUG Journal of Natural Studies 13 (2015).
  4. Ahmed HF, Hanaa AE, Azza MK, et al. Phenotypic and Molecular Identification of Klebsiella and Salmonella Species Isolated from Subclinical Mastitis Milk of Egyptian Buffalo. Global Veterinaria 16 (2016): 500-507.
  5. Argaw A. Review on epidemiology of clinical and subclinical mastitis on dairy cows. Food Sci and Qual Manag 52 (2016): 56-65.
  6. Banerjee S, Batabyal K, Joardar SN, et al. Detection and characterization of pathogenic Pseudomonas aeruginosa from bovine subclinical mastitis in West Bengal, India. Veterinary world 10 (2017): 738.
  7. Bansal BK, Gupta DK, Shafi TA, et al. Comparative antibiogram of coagulase-negative Staphylococci (CNS) associated with subclinical and clinical mastitis in dairy cows. Veterinary world 8 (2015): 421.
  8. Barkema HW, Green MJ, Bradley AJ, et al. Invited review: The role of contagious disease in udder health. Journal of dairy science 92 (2009): 4717-4729.
  9. Bayer AW, Kirby WM, Sherris JC, et al. Antibiotic susceptibility testing by a standardized single disc method. Am J clin pathol 45 (1966): 493-496.
  10. Becker K, Heilmann C, Peters G. Coagulase-negative staphylococci. Clinical microbiology reviews 27 (2014): 870-926.
  11. Beyene T, Hayishe H, Gizaw F, et al. Prevalence and antimicrobial resistance profile of Staphylococcus in dairy farms, abattoir and humans in Addis Ababa, Ethiopia. BMC research notes 10 (2017): 171.
  12. Bhat AM, Soodan JS, Singh R, et al. Incidence of bovine clinical mastitis in Jammu region and antibiogram of isolated pathogens. Veterinary world 10 (2017): 984.
  13. Bhatt VD, Ahir VB, Koringa PG, et al. Milk microbiome signatures of subclinical mastitis-affected cattle analysed by shotgun sequencing. Journal of applied microbiology 112 (2012): 639-650.
  14. Bhatt VD, Patel MS, Joshi CG, et al. Identification and antibiogram of microbes associated with bovine mastitis. Animal biotechnology 22 (2011): 163-169.
  15. Blowey RW, Edmondson P. Mastitis control in dairy herds. Cabi (2010).
  16. Carrillo-Casas EM, Miranda-Morales RE. Bovine mastitis pathogens: prevalence and effects on somatic cell count. InMilk Production-An Up-to-Date Overview of Animal Nutrition, Management and Health (2012).
  17. Bradley AJ. Bovine mastitis: an evolving disease. The veterinary journal 164 (2002): 116-128.
  18. Costa EO, Gandra CR, Pires MF, et al. Survey of bovine mycotic mastitis in dairy herds in the State of São Paulo, Brazil. Mycopathologia 124 (1993): 13-17.
  19. Coulona JB, Gasquib P, Barnouin J, et al. Effect of mastitis and related-germ on milk yield and composition during naturally-occurring udder infections in dairy cows. Animal Research 51 (2002): 383-393.
  20. Demme B, Abegaz S. Isolation and identification of major bacterial pathogen from clinical mastitis cow raw milk in Addis Ababa, Ethiopia. Acad. J. Anim. Dis 4 (2015): 44-51.
  21. dos Santos RD, Marin JM. Isolation of Candida spp. from mastitic bovine milk in Brazil. Mycopathologia 159 (2005): 251-253.
  22. Du JP. The role of anaerobic bacteria in bovine mastitis: a review. Journal of the South African Veterinary Association 60 (1989): 159-168.
  23. Dworecka-Kaszak B, Krutkiewicz A, Szopa D, et al. High prevalence of Candida yeast in milk samples from cows suffering from mastitis in poland. The Scientific World Journal (2012).
  24. Erbaş G, Parin U, Kirkan ş, et al. Identification of Candida strains with nested PCR in bovinemastitis and determination of antifungal susceptibilities. Turkish Journal of Veterinary and Animal Sciences 41 (2017): 757-763.
  25. Gelasakis AI, Mavrogianni VS, Petridis IG, et al. Mastitis in sheep–The last 10 years and the future of research. Veterinary Microbiology 181 (2015): 136-146.
  26. Gentilini E, Denamiel G, Betancor A, et al. Antimicrobial susceptibility of coagulase-negative staphylococci isolated from bovine mastitis in Argentina. Journal of Dairy Science 85 (2002): 1913-1917.
  27. Harby HA. Jakeen El Jakee and Refai, M.(1991):" The etiology and diagnosis of mastitis in Oman.". J. Egypt. Vet. Med. Asso 51: 783-95.
  28. Ikiz S, BAşARAN B, BINGÖL EB, et al. Presence and antibiotic susceptibility patterns of contagious mastitis agents (Staphylococcus aureus and Streptococcus agalactiae) isolated from milks of dairy cows with subclinical mastitis. Turkish Journal of Veterinary and Animal Sciences 37 (2013): 569-574.
  29. Kahir MA, Islam MM, Rahman AK, et al. Prevalence and risk factors of subclinical bovine mastitis in some dairy farms of Sylhet district of Bangladesh. Korean journal of veterinary Service 31 (2008): 497-504.
  30. Kalińska A, GoŁębiewski M, Wójcik A. Mastitis pathogens in dairy cattle–a review. World Scientific News 89 (2017): 22-31.
  31. Kivaria FM. Epidemiological studies on bovine mastitis in smallholder dairy herds in the Dar es Salaam region, Tanzania (Doctoral dissertation, Utrecht University).
  32. Kivaria FM, Noordhuizen JP. A retrospective study of the aetiology and temporal distribution of bovine clinical mastitis in smallholder dairy herds in the Dar es Salaam region of Tanzania. The Veterinary Journal 173 (2007): 617-622.
  33. Krukowski H, Tietze M, Majewski T, et al. Survey of yeast mastitis in dairy herds of small-type farms in the Lublin region, Poland. Mycopathologia 150 (2001): 5-7.
  34. Kuehn JS, Gorden PJ, Munro D, et al. Bacterial community profiling of milk samples as a means to understand culture-negative bovine clinical mastitis. PloS one 8 (2013).
  35. Kumar NV, Karthik A, Babu GS, et al. Prevalence of Fungal Species in the Antibiotic Resistant Bovine Mastitis in Chittoor, Andhra Pradesh. Indian Vet. J 93 (2016): 16-18.
  36. Kumar R, Yadav BR, Singh RS. Genetic determinants of antibiotic resistance in Staphylococcus aureus isolates from milk of mastitic crossbred cattle. Current microbiology 60 (2010): 379-386.
  37. Lagneau PE, Lebtahi K, Swinne D. Isolation of yeasts from bovine milk in Belgium. Mycopathologia 135 (1996): 99-102.
  38. León-Galván M, Barboza-Corona JE, Lechuga-Arana AA, et al. Molecular detection and sensitivity to antibiotics and bacteriocins of pathogens isolated from bovine mastitis in family dairy herds of central Mexico. BioMed research international (2015).
  39. Li G, Zhang T, Yang L, et al. Complete genome sequence of Achromobacter insolitus type strain LMG 6003T, a pathogen isolated from leg wound. Pathogens and disease 75 (2017).
  40. Mahami T, Odonkor S, Yaro M, et al. Prevalence of antibiotic resistant bacteria in milk sold in Accra. Int. Res. J. Microbiol 2 (2011): 126-132.
  41. Makovec JA, Ruegg PL. Results of milk samples submitted for microbiological examination in Wisconsin from 1994 to 2001. Journal of dairy science 86 (2003): 3466-3472.
  42. Manie T, BRÖZEL VS, Veith WJ, et al. Antimicrobial resistance of bacterial flora associated with bovine products in South Africa. Journal of food protection 62 (1999): 615-618.
  43. Miller CS, Handley KM, Wrighton KC, et al. Short-read assembly of full-length 16S amplicons reveals bacterial diversity in subsurface sediments. PloS one 8 (2013).
  44. Munoz MA, Welcome fl, Schukken YH, et al. Molecular epidemiology of two Klebsiella pneumoniae mastitis outbreaks on a dairy farm in New York State. Journal of clinical microbiology 45 (2007): 3964-3971.
  45. Nam HM, Lim SK, Kang HM, et al. Prevalence and antimicrobial susceptibility of gram-negative bacteria isolated from bovine mastitis between 2003 and 2008 in Korea. Journal of dairy science 92 (2009): 2020-2026.
  46. Olivares-Pérez J, Kholif AE, Rojas-Hernández S, et al. Prevalence of bovine subclinical mastitis, its etiology and diagnosis of antibiotic resistance of dairy farms in four municipalities of a tropical region of Mexico. Tropical animal health and production 47 (2015): 1497-1504.
  47. Pachauri S, Varshney P, Dash SK, et al. Involvement of fungal species in bovine mastitis in and around Mathura, India. Vet World 6 (2013): 393-395.
  48. Pitkälä A, Haveri M, Pyörälä S, et al. Bovine mastitis in finland 2001—prevalence, distribution of bacteria, and antimicrobial resistance. Journal of dairy science 87 (2004): 2433-2441.
  49. Pyörälä S, Taponen S. Coagulase-negative staphylococci—Emerging mastitis pathogens. Veterinary microbiology 134 (2009): 3-8.
  50. Quinn PJ. Clinical veterinary microbiology (1994).
  51. Ranjan R, Swarup D, Patra RC, et al. Bovine protothecal mastitis: a review. Perspectives in Agriculture, Veterinary Sciences, Nutrition and Natural Resources 1 (2006): 1-7.
  52. Rofaida ME. Isolation and identification of the bacteria associated with bovine mastitis and detection of their specific antibodies in milk and sera (Doctoral dissertation, MSc thesis, Dep. of Micro., Fac. of Vet. Med., UofK, Sudan).
  53. Sadashiv SO, Kaliwal BB. Isolation, characterization and antibiotic resistance of Bacillus sps. from bovine mastitis in the region of north Karnataka, India. Int. J. Curr. Microbiol. App. Sci 3 (2014): 360-373.
  54. Salih RR. BOVINE MASTITIS CAUSED BY Bacillus spp. IN KHARTOUM STATE, SUDAN. Journal of Veterinary Medicine and Animal Production 2 (2013).
  55. Sharif AA, Umer MU, Muhammad GH. Mastitis control in dairy production. J. Agric. Soc. Sci 5 (2009): 102-105.
  56. Sharma N, Maiti SK, Sharma KK. Prevalence, etiology and antibiogram of microorganisms associated with Sub-clinical mastitis in buffaloes in Durg, Chhattisgarh State (India). International Journal of Dairy Science 2 (2007): 145-151.
  57. Sharma N, Singh NK, Bhadwal MS. Relationship of somatic cell count and mastitis: An overview. Asian-Australasian Journal of Animal Sciences 24 (2011): 429-438.
  58. Smit E, Leeflang P, Glandorf B, et al. Analysis of fungal diversity in the wheat rhizosphere by sequencing of cloned PCR-amplified genes encoding 18S rRNA and temperature gradient gel electrophoresis. Appl. Environ. Microbiol. 65 (1999): 2614-2621.
  59. Srednik ME, Archambault M, Jacques M, et al. Detection of a mecC-positive Staphylococcus saprophyticus from bovine mastitis in Argentina. Journal of global antimicrobial resistance 10 (2017): 261-263.
  60. Sukumar K, James PC. Incidence of fungal mastitis in cattle. Tamilnadu Journal of Veterinary and Animal Sciences 8 (2012): 356-359.
  61. Sumathi BR, Veeregowda BM, Amitha RG. Prevalence and antibiogram profile of bacterial isolates from clinical bovine mastitis. Veterinary World 1 (2008): 237-238.
  62. Taponen S, Salmikivi L, Simojoki H, et al. Real-time polymerase chain reaction-based identification of bacteria in milk samples from bovine clinical mastitis with no growth in conventional culturing. Journal of dairy science 92 (2009): 2610-2617.
  63. Taponen S, Supré K, Piessens V, et al. Staphylococcus agnetis sp. nov., a coagulase-variable species from bovine subclinical and mild clinical mastitis. International journal of systematic and evolutionary microbiology 62 (2012): 61-65.
  64. Zeryehun T, Abera G. Prevalence and bacterial isolates of mastitis in dairy farms in selected districts of eastern Harrarghe Zone, Eastern Ethiopia. Journal of veterinary medicine (2017).
  65. Türkyilmaz S, Yildiz Ö, Oryaşin E. Molecular identification of bacteria isolated from dairy herds with mastitis. The Journal of the Faculty of Veterinary Medicine, University of Kafkas 16 (2010): 1025-1032.
  66. Ventola CL. The antibiotic resistance crisis: part 1: causes and threats. Pharmacy and therapeutics 40 (2015): 277.
  67. Wawron WŁ, Bochniarz MA, Piech T. Yeast mastitis in dairy cows in the middle-eastern part of Poland. Bull Vet Inst Pulawy 54 (2010): 201-204.
  68. White TJ, Bruns T, Lee SJ, et al. Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. PCR protocols: a guide to methods and applications 18 (1990): 315-322.
  69. Younis G, Awad A, Ashraf N. Molecular and phenotypic characterization of antimicrobial resistance in gram negative bacteria recovered from subclinical mastitis. Adv. Anim. Vet. Sci 5 (2017): 196-204.

    Editor In Chief

    Masashi Emoto

  • Professor of Laboratory of Immunology
    Department of Laboratory Sciences
    Gunma University Graduate School of Health Sciences
    Gunma, Japan

© 2016-2021, Copyrights Fortune Journals. All Rights Reserved!