The Maasai community that straddle the Kenyan and Tanzanian borders are pastoralists keeping a large number of livestock. However, in recent years, sedentary livelihoods have been observed in some parts of Kajiado and Narok Counties, in Kenya. In a pastoralist production system, bovine milk is highly regarded in terms of nutrition and market value. The community mainly uses traditional hand milking to milk the cows that are reared under the extensive system (Caudell et al., 2019). The Maasai have traditionally kept indigenous breed of cattle such as the Zebu and Boran. However, these breeds have low milk production but survive the semi-arid terrain and hence support their livelihoods. In recent decades, the pastoralists have also adopted exotic and their crossbreeds to improve the production of milk Ruto et al.,2008). These exotic breeds are more demanding in maintenance as they require modern housing, feed and regular veterinary attendance due to high prevalence of diseases, such as mastitis (Gitau et al., 2014).
Mastitis is a multi-etiologic disease that can be classified as either clinical or subclinical (Abrahmsén et al., 2014; Gitau et al.,2014). Different studies have isolated a number of bacteria from the milk of dairy cattle with sub-clinical mastitis (SCM), and the main bacteria include Staphylococcus aureus, Streptococcus agalactiae, Corynebacterium bovis, Mycoplasma species, Streptococcus uberis, coliforms (Escherichia coli, Klebsiella spp. and Enterobacter aerogenes), Serratia spp., Pseudomonas spp., Proteus spp., Streptococcus spp. and Enterobacter spp. (Birhanu et al., 2017; Gangwal et al., 2017; Mpatswenumugabo et al., 2017). SCM is difficult to diagnose, and this often leads to prolonged losses in milk yields, changes in milk composition, and an increase in the cost of treatment (Zeryehun & Abera 2017). Several studies conducted in Kenya have shown SCM in dairy animals in high-potential areas at prevalence ranging from 36% to 87% (Gitau et al., 2014; Mahlangu et al., 2018; Mureithi & Njuguna, 2016; Wanjohi et al., 2013). Diagnosis and screening of SCM are mainly done using the tests such as the California mastitis test (CMT) (Shem et al.,2002) which are often not available to farmers. For clinical mastitis, following diagnosis, administration of antibiotics is undertaken by farmers and animal health practitioners. Aggressive administration of antibiotics and misuse of antibiotics in the management of mastitis is often associated with the emergence and spread of antimicrobial resistance (AMR) (Li et al., 2018). Among the pastoralists in Kenya, the administration of these drugs by farmers is common (Ogola et al.,2007), and this can lead to an increase in the selection of antibiotic-resistant strains. However, literature is scarce on the occurrence of mastitis and AMR among dairy animals kept by pastoralists in the country.
The objective of the current study was to determine the prevalence and risk factors for SCM, and the susceptibility of the bacteria isolated from the milk of cows kept by Maasai pastoralists to common antibiotics used for the management of SCM.
MATERIALS AND METHODS Description of the study areaThe study was conducted in Kajiado Central sub-county which is primarily inhabited by the Maasai community. The sub-county is 4212.6 square km and is divided into five administration wards, namely Matapato North, Matapato South, Ildamat, Dalalakutuk and Purko. It is semi-arid with temperatures ranging from 20 to 30°C and rainfall of 500–1200 mm per annum. There are generally two rainy seasons; long rains from March to May and short rains between October and December. The human population in the sub-county is 161,862 and has a population density of 51 people per square km (Kenya National Bureau of Statistics [KNBS], 2019).
Study design, sample size determination administration of questionnairesThe descriptive cross-sectional study was carried out between September and December 2019. The study involved a total of 202 lactating cows, whose number was calculated based on Thrushfield (2007) equation, using 95% confidence level, and 5% of desired precision, results showed that a minimum of 161 lactating cows were sufficient for the current study.
The SCM test was done for the 202 lactating cows from 40 small-scale households in the five administrative wards followed by collection of milk from the SCM positive cows. The number of households sampled per ward was chosen based on the ward cattle population and was identified according to the information provided by the local agricultural extension officers. From each target herd, 5% of cattle were sampled. Structured questionnaires were administered to the livestock farmers to obtain information on the production system (intensive and extensive), cattle breed, lactation stage, parity and history of occurrence of mastitis. These were risk factors used to conduct univariate statistical analysis.
Milk sampling and California mastitis test (CMT)Milk from all teats of the 202 lactating cows was used to screen for SCM using CMT during routine milking hours. Briefly, the teats were individually cleansed using cotton wool saturated with 70% ethanol and dried with disposable towels. Five millilitre of milk from the different teats was milked into the CMT paddle, and an equal volume of the CMT reagent (Immucell RP) was added. A score of 0, trace and 1 (one) was considered as a negative, a positive CMT test was scored as 2 or 3, which corresponds to a somatic cell count of 2560,000 and ≥10,000,000, respectively (Kivaria et al., 2007). A pool of milk from the four teats of each cow showing a positive CMT test in ≥1 teat was collected into a 10 mL sterile collection tube, stored in a cool box with ice packs and transported to the Institute of Primate Research, Nairobi diagnostic laboratory for further study.
Culture and identification of bacteriaBacteria isolation was accomplished by inoculating 5 mL of each milk sample onto sheep blood agar (SBA) (HiMedia) and MacConkey agar (HiMedia) plates. Inoculated plates of MacConkey agar were incubated at 37°C for 18–24 h in ambient aeration and SBA in an environment enriched with 5% CO2. Morphology of colonies growing on SBA plates was described based on colour and ability to cause haemolysis. Discrete colonies were re-plated on Tryptone soy agar to obtain pure isolates subjected to Gram staining. An API strip kit from bioMérieux was used to confirm the ambiguous, discrete colonies and the kits were interpreted using the VITEK 2 Compact software from bioMérieux attached to the kits. Catalase test was performed on all Gram-positive cocci to distinguish isolated staphylococci from streptococci. The isolated S. aureus were confirmed by performing the coagulase test. Species of bacteria from colonies obtained from MacConkey agar plates were identified based on their ability to ferment lactose followed by Gram staining and biochemical testing panel reactions (Mahlangu et al., 2018).
Antimicrobial susceptibility testsSusceptibility of antibiotics to the most prevalent bacterial isolate in the current study (Staphylococcus spp.) was done. The Kirby–Bauer disk diffusion method was used to test the susceptibility of isolated coagulase negative staphylococci (CNS) and S. aureus isolates against 14 antibiotic disks (HiMedia); amoxicillin (30 μg), augmentin, (20/30 μg), oxacillin (1 μg), cefoxitin (30 μg), ciprofloxacin (30 μg), clindamycin (2 μg), gentamicin (10 μg), streptomycin (10 μg), erythromycin (15 μg), vancomycin (20 μg), tetracycline (30 μg), ceftriaxone (30 μg), ceftazidime (30 μg) and cefotaxime (30 μg). Briefly, a uniform suspension of each isolate was prepared and adjusted to a concentration equivalent to 0.5 McFarland with sterile normal saline. Each suspension was evenly spread on two Mueller–Hinton agar (HiMedia) plates followed by placing seven antibiotics disks on every plate. Zones of inhibition were measured and reported as sensitive (S), intermediate resistant (I), or resistant (R) based on the Clinical & Laboratory Standard institute (CLSI) (2018). Isolates considered multi-drug resistant were found to be resistant to three or more antibiotics from different families (Magiorakos et al., 2012).
Statistical analysisData were entered into a Microsoft Office Excel spreadsheet Version 16.0 (Microsoft Corp.) and then analysed using the R statistical programme (Version 1.1.447, R Studio, Inc). Descriptive statistics were expressed as percentages and frequencies, and data were presented in tables. The prevalence of SCM (cow-level) was determined as the number of CMT-positive cows divided by the total number of sampled cows. A cow was assumed to be CMT-positive if milk from, at least, one quarter was positive. The proportion of the resistant bacterial isolates was determined as the number of all the isolates resistant to at least one of the antibiotics out of the total number of bacterial isolates. The prevalence of SCM (cow-level) was the one used in undertaking the statistical analysis evaluating the association of mastitis with the risk factors. Univariate analysis was used to assess the association between the dependent variable (the mastitis outcome based on CMT testing, 0,1 = negative, 2,3 = positive) and independent variables (risk factors). Fisher's exact test was used to determine the association of SCM and farm-level variables with the occurrence of resistance. The variables with p ≤ 0.05 were considered for a final model and analysed using multivariable logistic regression analysis. Within this analysis, the statistical significance was set at p ≤ 0.05.
RESULTS Characteristics of the farm and cattle sampledA total of 40 farms were selected from the five wards in Kajiado Central sub-county. Most (85%) of the sampled farms practiced production systems while 15% were semi-intensive livestock farmers. Cattle kept by farmers in the study area comprised indigenous, exotic and crossbreeds. The exotic breeds included Sahiwal (45.5%), Friesian (17.2%), Ayrshire (1.9%) and Jersey (1.5%), whereas the indigenous breeds were Boran (15.3%), Maasai Zebu (10.9%) and crossbreeds (7.4%).
Prevalence of cow-level sub-clinical mastitis (SCM) and bacterial identificationThe total number of lactating cows sampled in the study was 202. Using CMT, the prevalence of mastitis at quarter- and cow-level was 31.7% and 53%, respectively. The highest (73.1%) prevalence of SCM was recorded in cows originating from the Matapato North ward (Table 1).
TABLE 1 Prevalence of subclinical mastitis in lactating cows (n = 202) in different wards of Kajiado Central sub-county, Kenya.
| Ward | Total sampled | Positive | Prevalence (%) |
| Matapato North | 56 | 31 | 55.4 |
| Matapato South | 52 | 38 | 73.1 |
| Purko | 24 | 14 | 58.3 |
| Ildamat | 33 | 4 | 12.1 |
| Dalalekutuk | 37 | 20 | 54.1 |
| Total | 202 | 107 | 53.0 |
A total of 176 bacteria isolates were obtained from the 107 SCM positive milk samples. There were 19 bacterial species isolated from the milk samples with the majority being CNS (40.1%), S. aureus (15.8%) and Micrococcus spp. (10.4%). Other isolates obtained included Enterococcus spp., Corynebacterium spp., Enterobacter cloacae, Pantoea spp., Lactococcus spp., Klebsiella pneumoniae, Lactobacillus spp., Pseudomonas luteola, Klebsiella ozaenae, Pasteurella pneumotropica, E. coli, Aeromonas hydrophila, Bacillus spp., Pseudomonas aeruginosa, Stenotrophomonas maltophilia and Kluyvera spp. The prevalence of these isolates is shown in Table 2.
TABLE 2 Prevalence of specific bacteria isolated from milk of cattle in Kajiado sub-county Kenya.
| Isolate | Number of samples | Frequency (n = 202) (%) |
| CNS | 81 | 40.1 |
| Staphylococcus aureus | 32 | 15.8 |
| Micrococcus spp. | 21 | 10.4 |
| Enterococcus spp. | 10 | 5.0 |
| Corynebacterium spp. | 9 | 4.5 |
| Enterobacter cloacae | 9 | 4.5 |
| Pantoea spp. | 7 | 3.5 |
| Lactococcus spp. | 6 | 3.0 |
| Klebsiella pneumoniae | 4 | 2.0 |
| Lactobacillus spp. | 3 | 1.5 |
| Pseudomonas luteola | 3 | 1.5 |
| Klebsiella ozaenae | 3 | 1.5 |
| Aeromonas hydrophila | 2 | 1.0 |
| Pasteurella pneumotropica | 2 | 1.0 |
| Escherichia coli | 2 | 1.0 |
| Bacillus spp. | 1 | 0.5 |
| Pseudomonas aeruginosa | 1 | 0.5 |
| Stenotrophomonas maltophilia | 1 | 0.5 |
| Kluyvera spp. | 1 | 0.5 |
Abbreviation: CNS, coagulase-negative staphylococci.
Prevalence based on risk factorsSub-clinical mastitis was observed across all breeds of cattle. Breed was shown to be a significant risk factor (p = 0.02) with the highest prevalence of SCM being observed among the exotic breeds, whereas SCM prevalence in the indigenous breeds was slightly lower. Cows that were kept in an extensive system of production had a significantly (p = 0.018) higher prevalence of SCM than those kept in semi-intensive systems. The highest prevalence of SCM was found in the cattle at the mid-lactation stage, whereas the lowest prevalence was found in the early lactation stage. The lactation stage was not significantly associated with the prevalence of SCM (p = 0.66). The lowest prevalence of SCM was found in primiparous cows, and the highest prevalence was in multiparous cows. However, parity had no significant effect (p = 0.30) on the occurrence of SCM. The highest prevalence of SCM was found among the dairy cattle that were kept in structures that had poor hygiene, whereas a lower prevalence was noted in cows kept in structures with good hygiene. However, hygiene level was not a significant (p = 0.17) of mastitis. The previous history of occurrence of mastitis was not (p = 0.17) associated with the prevalence of SCM in sample cows (Table 3).
TABLE 3 Prevalence of bovine subclinical mastitis based on various factors.
The antibiotic sensitivity of the isolated CNS and S. aureus was tested against 14 antibiotics. CNS were shown to be more resistant against ceftazidime (79.1%), amoxycillin (34.6%), oxacillin (32.1%), streptomycin (32.1%), vancomycin (22.2%) and tetracycline (23.5%) (Table 4). As for S. aureus, CNS were more sensitive to ciprofloxacin (95.1%) and augmentin (92.6%). S. aureus isolates showed varied resistance to all the tested antibiotics with the highest resistance being against ceftazidime (75%), amoxycillin (50%), streptomycin (46.9%) and erythromycin (25%). Several S. aureus isolates were resistant to oxacillin (34.4%) and cefoxitin (12.5%), which are used as surrogate indicators of methicillin resistance. Nevertheless, most of the S. aureus were highly sensitive to ciprofloxacin (100%) and augmentin (93.7%).
TABLE 4 Antibiotic sensitivity profile of coagulase-negative Staphylococcus (CNSs) (n = 81) and Staphylococcus aureus (n = 32) isolated from milk of cattle in Kajiado sub-county, Kenya.
| CNS | Staphylococcus aureus | |||||
| Antibiotic used | Resistant CNS (%) | Intermediate CNS (%) | Susceptible CNS (%) | Resistant S. aureus (%) | Intermediate S. aureus (%) | Susceptible S. aureus (%) |
| Amoxicillin | 28 (34.6) | 4 (4.9) | 49 (60.5) | 16 (50) | 1 (3.1) | 15 (46.8) |
| Augmentin | 6 (7.4) | 75 (92.6) | 2 (6.3) | 0 | 30 (93.7) | |
| Oxacillin | 26 (32.1) | 55 (67.9) | 11 (34.4) | 21 (65.6) | ||
| Cefoxitin | 9 (11.1) | 72 (88.9) | 4 (12.5) | 29 (90.6) | ||
| Ciprofloxacin | 1 (1.2) | 3 (3.7) | 77 (95.1) | 32 (100) | ||
| Clindamycin | 5 (6.2) | 20 (2.5) | 56 (69.1) | 9 (28.1) | 24 (75) | |
| Gentamicin | 3 (3.7) | 13 (16.1) | 65 (80.2) | 6 (18.6) | 26 (81.3) | |
| Streptomycin | 26 (32.1) | 14 (17.3) | 41 (50.6) | 15 (46.9) | 8 (25) | 9 (28.1) |
| Erythromycin | 16 (19.8) | 15 (18.5) | 50 (61.7) | 8 (25) | 24 (75) | |
| Vancomycin | 18 (22.2) | 63 (77.8) | 5 (15.6) | 27 (84.4) | ||
| Tetracycline | 19 (23.5) | 9 (11.1) | 53 (65.4) | 6 (18.6) | 2 (6.3) | 24 (75) |
| Ceftriaxone | 2 (2.5) | 20 (24.7) | 59 (72.8) | 3 (9.4) | 3 (9.4) | 26 (81.3) |
| Cefotaxime | 3 (3.7) | 12 (14.8) | 66 (81.5) | 3 (9.4) | 29 (90.6) | |
| Ceftazidime | 64 (79.1) | 13 (16.1) | 4 (4.9) | 24 (75) | 5 (15.6) | 3 (9.4) |
Multi-drug resistance (MDR) in the isolated CNS and S. aureus was observed. The levels of MDR across the different antibiotic classes ranged from 1.2% to 23.45% with the highest resistance occurring in the tetracycline class.
DISCUSSIONThe current study was geared towards determining the prevalence of SCM and the occurrence of antibiotic resistance in bacteria isolated from the milk of dairy cattle in Kajiado Central sub-county, an area whose predominant population is the Maasai community pastoralists. The reported cow-level prevalence in the study was comparable to that reported in Kajiado North sub-county 51.2% (Ngotho et al., 2022). The same range of prevalence has also been reported in Ethiopia (42.4%–57%) (Zeryehun, & Abera, 2017; Tora et al., 2022; Girma & Tamir, 2022) but a higher prevalence has been reported elsewhere in the African continent; Uganda (>60%) (Miyama et al., 2020; Ssajjakambwe et al., 2017) and Rwanda >70% (Ndahetuye et al., 2019). However, the same range of prevalence has been reported in Asian countries (50%) (Bari et al., 2022; Chen et al., 2023). This prevalence is, however, lower than that reported in other parts of Kajiado county (74%) (Mbindyo et al., 2020) and other parts of Kenya (64%) (Mureithi & Njuguna, 2016). The differences observed from the studies could be due to variations in the production systems. For example, in studies done on exotic breeds from intensive production systems, the prevalence could be higher (Mureithi & Njuguna, 2016). In the current study, exotic breeds were shown to have a higher prevalence of mastitis compared to the indigenous, which is like studies reported elsewhere (Fesseha et al., 2021; Khasapane et al., 2023). The exotic breeds have a higher susceptibility to mastitis possibly due to high milk production (Fesseha et al., 2021; Khasapane et al., 2023). However, in our study, the moderate-to-high prevalence of SCM among the Boran and Zebu breeds was unexpected as these animals are expected to be more resistant to the disease. It was also possible that the crossbreeding of local and exotic cattle could have caused the observed prevalence of SCM. The animals when kept under the extensive free-range system could have been exposed to stressing situations that cause the spread of mastitis. This points to the need for the pastoralist farmers in the area to also focus on control of mastitis among the indigenous and cross breeds as they are equally susceptible to the disease.
In this study, CNS, S. aureus, Micrococcus spp., Enterococcus spp. and Corynebacterium spp. were the most common bacteria isolated from the milk of the cattle which agreed with the results observed by Mbindyo et al. (2020) and Ngotho et al. (2022). A similar range of bacterial species have been isolated in cattle from Uganda (Ali et al., 2021); Ethiopia (Zeryehun & Abera, 2017) and Rwanda (Mpatswenumugabo et al., 2017). With the increasing number of studies showing globally that CNS is one of the most frequent bacteria in milk, there is a need to identify the actual species in a future study. Currently, the relevance of CNS as a cause of bovine mastitis is debatable, with pathogenicity of CNS varying from being protective to being the cause of SCM (De Vliegher et al., 2009). A review by De Vliegher et al. (2012) showed that intramammary infection by CNS in early lactation does not warrant treatment and the impact at herd level, depends on many factors such as epidemiology, the nature of the disease, the causative pathogens, ability of the animals to cope with the disease and management changes.
The second most abundant bacterial species was S. aureus whose prevalence is lower to that reported in Kenya 35.5% (Mureithi & Njuguna, 2016), Rwanda at 20.6% (Mpatswenumugabo et al., 2017), Tanzania at 36.8 % (Suleiman et al., 2018) and Algeria at 40% (Saidi et al., 2019). In most studies, S. aureus is the main cause for bovine clinical mastitis and has greater pathogenicity than CNS. Among the pastoralist, S. aureus from cows with SCM can be transmitted to human beings through the consumption of raw milk which is common with the pastoralists (Shem et al.,2002).
The other important bacteria isolated in the cows included Micrococcus spp., Enterococcus spp., Corynebacterium spp. and K. pneumoniae. For K. pneumoniae and Micrococcus spp., the prevalence noted in this study was like those reported in Ethiopia (Balemi et al., 2021). The prevalence of E. coli and Corynebacterium spp. was close to the one reported by Mbindyo et al. (2020) in intensively kept cows in Kenya. Klebsiella spp. and E. coli are part of coliforms which are the main causes for environmental mastitis in domestic ruminants (Cobirka et al., 2020).
Our results showed that the isolated CNS and S. aureus isolates were resistant to the common antibiotics used in the treatment of mastitis and other bacterial diseases in animals and humans. In both isolates, the highest resistance was observed against ceftazidime, amoxycillin and streptomycin. This is like other studies (Govender et al., 2019). A substantial number of CNS were resistant to oxacillin and cefoxitin which are used surrogate indicators of methicillin resistance. Methicillin-resistant S. aureus arising from livestock has emerged as a serious threat in managing various conditions in human beings. On the other hand, most the Staphylococcus spp. isolates were sensitive to augmentin, gentamycin and ciprofloxacin which is different from what was observed in isolates from milk of intensively kept cattle in Kenya (Gitau et al., 2014; Mbindyo et al., 2020). Other antibiotics are shown in the current study to be having high sensitivity against the Staphylococcus spp. included ceftriaxone, cefotaxime and clindamycin. These antibiotics could still be used in the treatment of mastitis where resistance has emerged to the other antibiotics. High susceptibility of cephalosporin and ciprofloxacin has been observed in CNS-isolated bovine mastitis in Ethiopia (Gizaw et al., 2020).
CONCLUSIONThe high prevalence of SCM observed in this study shows the need for improved research efforts to control SCM in pastoral systems in the study region. This can be done through sensitizing farmers on the need for regular screening of dairy cattle for SCM using CMT as well as training farmers in proper husbandry geared towards improved milking of the animals. Antibiotic resistance was also high in the study area and hence there is a need to sensitize animal health professionals and farmers on measures that can slow down the emergence and spread of resistance in the area. This could be achieved by encouraging the farmers to consult veterinarians for the treatment of their animals and compliance with the prudent use of antibiotics. Considering the observed high prevalence of SCM and resistance, there is also a need to determine whether there is a possible spread of these bacteria to humans through such means as consumption of raw milk which is common among the pastoralists in the study area (Onono et al., 2019).
AUTHOR CONTRIBUTIONSStudy concept and design; acquisition of data; analysis and interpretation of data; drafting of the manuscript; critical revision of the manuscript for important intellectual content: Lynda Michira. Study concept and design; acquisition of data; analysis and interpretation of data; drafting of the manuscript; critical revision of the manuscript for important intellectual content; funding acquisition and study supervision: John Kagira. Study concept and design; analysis and interpretation of data; critical revision of the manuscript for important intellectual content; funding acquisition and study supervision: Naomi Maina. Study concept and design; drafting of the manuscript; funding acquisition and study supervision: Maina Ngotho. Acquisition of data; analysis and interpretation of data; critical revision of the manuscript for important intellectual content: Keneth Waititu. Acquisition of data; analysis and interpretation of data; drafting of the manuscript; critical revision of the manuscript for important intellectual content: Edidah Ongera. Analysis and interpretation of data; critical revision of the manuscript for important intellectual content; funding acquisition and study supervision: Daniel Kiboi.
CONFLICT OF INTEREST STATEMENTThe authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article.
FUNDING INFORMATIONGrand Challenges Africa, Grant Number: GCA/AMR/rnd2/079
ETHICS STATEMENTEthical approval was obtained from the Institutional Ethical Review Committee. Milk samples were obtained with the help of the farmers who volunteered to participate in the study under the supervision of veterinary officers from the county veterinary office. The protocols used for sampling, bacterial isolation and antibiotic susceptibility testing were performed in agreement with the Animal Diseases act, Section 20, Act of 1984 (Act No. 35 of 1984).
DATA AVAILABILITY STATEMENTThe data collected and analysed during this study are available from the corresponding author on reasonable request.
PEER REVIEWThe peer review history for this article is available at
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Abstract
Background
Literature is scarce on the occurrence of bovine mastitis and antimicrobial resistance among dairy animals kept by pastoralists in the Kenya.
Objectives
A cross-sectional study was carried out to investigate the prevalence and risk factors of subclinical mastitis (SCM) and evaluate the antibiotic sensitivity of bacteria isolated from dairy cattle kept by farmers in Kajiado Central sub-county, Kenya.
Methods
A total of 202 lactating cows from 40 farms were sampled. Milk from the cows was screened for SCM using the California mastitis test, and the bacteria present in the milk samples were determined using standard bacteriological methods. The sensitivity of the isolated coagulase-negative staphylococci (CNS) and Staphylococcus aureus against antibiotics was tested using the Kirby–Bauer disk diffusion method.
Results
The prevalence of SCM at quarter- and cow-level was 31.7% and 53%, respectively. The prevalence of SCM was significantly higher (p < 0.05) in exotic breeds of cattle and those kept under an extensive system of production. A total of 19 bacterial species were isolated with the majority being CNS (40.1%), S. aureus (15.8%) and Micrococcus spp. (10.4%). S. aureus isolates showed varied resistance to the tested antibiotics with the highest resistance being against ceftazidime (75%), amoxycillin (50%) and streptomycin (46.9%). Several S. aureus isolates were resistant to oxacillin (34.4%) and cefoxitin (12.5%). CNSs were more resistant against ceftazidime (79.1%), amoxycillin (34.6%) and oxacillin (32.1%). Majority (92%–100%) of the Staphylococcus spp. were highly sensitive to ciprofloxacin a fluoroquinolone and augmentin.
Conclusions
The high prevalence of SCM and bacteria resistant to antibiotics shows a need for animal health professionals and farmers to develop strategies for the management of mastitis and antibiotic resistance in dairy cows in the study area.
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Details
; Maina, Naomi 1 ; Waititu, Keneth 3 ; Kiboi, Daniel 1 ; Ongera, Edidah 1 ; Maina Ngotho 2 1 Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
2 Department of Animal Sciences, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
3 Department of Animal Science, Institute of Primate Research, Nairobi, Kenya