scholarly journals Staphylococcus aureus isolates from bovine subclinical mastitis in central Ethiopia revealed the presence of antimicrobial resistance and resistant genes

Author(s):  
Desiye Tesfaye Tegegne ◽  
Gezahegne Mamo ◽  
Hika Waktole ◽  
Gebrerufael Girmay

Abstract Background: Staphylococcus aureus is one of the predominant causative agents of mastitis disease in dairy herds. Mastitis disease has a negative impact in the economic losses in the dairy sector across the globe. The aims of this study were to determine the prevalence and detect antimicrobial resistance genes in the Staphylococcus aureus isolated from milk samples of subclinical bovine mastitis in Central Ethiopia.Methods: A total of 265 lactating dairy cows from various dairy farms in four different geographical locations were screened by California mastitis test (CMT) for bovine subclinical mastitis. One-hundred thirty CMT positive milk samples were collected and transported to laboratory. Different biochemical tests and polymerase chain reaction (PCR) were used for the identification of S. aureus isolates. Finally, phenotypic and genotypic methods were performed for detection of some antimicrobial resistance patterns and genes (mecA, ermA, ermC, and msrA), respectively. Results: From total of 265 lactating dairy cows screened, 49% (n=130) were positive for bovine subclinical mastitis. One-hundred thirty mastitic milk samples were subjected to bacterial culturing, one hundred (76%) S. aureus isolates were identified based on phenotypic characters. Sixty-eight confirmed S. aureus isolates were obtained using PCR. Of the sixty-eight isolates tested 12 samples were contained the methicillin resistance gene A (mecA). No amplification was observed for the erythromycin resistance genes (ermA, ermC, and msrA). Conclusion: The high resistance of Staphylococcus aureus to commonly used antimicrobials contribute in dairy farms may cause health problems in the community consuming raw milk purchased from these farms.

2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Desiye Tesfaye Tegegne ◽  
Gezahegne Mamo ◽  
Hika Waktole ◽  
Yohannes Equar Messele

Abstract Purpose Staphylococcus aureus (S. aureus) is the most important pathogen involved in bovine mastitis in dairy production. S. aureus produces a spectrum of extracellular protein toxins and virulence factors which are thought to contribute to the pathogenicity of the organism. The aim of this work was to isolate and molecular characterize S. aureus associated with bovine subclinical mastitis in the central part of Ethiopia. Methods A total of 265 lactating dairy cows from various dairy farms in four different geographical locations were screened by the California mastitis test (CMT) for bovine subclinical mastitis. One hundred thirty CMT-positive milk samples were collected and transported to the laboratory. Different biochemical tests and polymerase chain reaction (PCR) were used for the identification of S. aureus isolates. Finally, PCR was performed for molecular detection of virulence genes. Results From a total of 265 lactating dairy cows screened, 49% (n = 130) were positive for bovine subclinical mastitis. One hundred thirty mastitic milk samples were subjected to bacterial culturing, and one hundred (76%) S. aureus isolates were identified based on phenotypic characters. Sixty-eight confirmed S. aureus isolates were obtained using PCR. The confirmed S. aureus isolates were tested for six virulence genes (tsst-1, hlb, eta, sea, clfA, and icaD) using PCR. Of the six virulence genes screened from all the isolates, only two (clfA and eta) were detected in the isolates. Out of 68 isolates, 25% and 22% were possessed the eta and clfA genes, respectively. Conclusion The presence of Staphylococcus aureus having virulence genes (eta and clfA) revealed that mastitis is a major concern nowadays affecting animal health, milk quality, and yield. Further genomic study of these isolates will provide broad new insights on virulence.


2021 ◽  
Author(s):  
Desiye Tesfaye Teegegne ◽  
Gezahegne Mamo ◽  
Hika Waktole ◽  
Yohannes Equar Messele

Abstract Purpose: Staphylococcus aureus (S. aureus) is the most important pathogen involved in bovine mastitis in dairy production. S. aureus produces a spectrum of extracellular protein toxins and virulence factors which are thought to contribute to the pathogenicity of the organism. The aim of this work was to isolate and molecular characterize S. aureus associated with bovine subclinical mastitis in central part of Ethiopia.Methods: A total of 265 lactating dairy cows from various dairy farms in four different geographical locations were screened by California mastitis test (CMT) for bovine subclinical mastitis. One-hundred thirty CMT positive milk samples were collected and transported to laboratory. Different biochemical tests and polymerase chain reaction (PCR) were used for the identification of S. aureus isolates. Finally, PCR was performed for molecular detection of virulence genes. Results: From total of 265 lactating dairy cows screened, 49% (n=130) were positive for bovine subclinical mastitis. One-hundred thirty mastitic milk samples were subjected to bacterial culturing, one hundred (76%) S. aureus isolates were identified based on phenotypic characters. Sixty-eight confirmed S. aureus isolates were obtained using PCR. The confirmed S. aureus isolates were tested for six virulence genes (tsst-1, hlb, eta, sea, clfA and icaD) using PCR. Of the six virulence genes screened from all the isolates, only two (clfA and eta) were detected in the isolates. Out of 68 isolates, 25% and 22% were possessed the eta and clfA genes, respectively. Conclusion: Presence of Staphylococcus aureus having virulence genes (eta and clfA) revealed that mastitis is a major concern nowadays affecting animal health, milk quality, and yield. Further genomic study of these isolates will provide broad new insights on virulence.


2017 ◽  
Vol 33 (4) ◽  
pp. 465-473
Author(s):  
Annamaria Galfi ◽  
Miodrag Radinovic ◽  
Ivana Davidov ◽  
Mihajlo Erdeljan ◽  
Zorana Kovacevic

Control of udder health is an essential element in the process of safe milk production. Thus through the mastitis control program dairy farms regularly conduct measures of detection and prevention of udder diseases. Subclinical mastitis is an important disease of dairy cows causing economic losses and physical and chemical changes in milk. The aim of this research was to evaluate the usefulness of the California and the Draminski mastitis test to detect the subclinical mastitis in dairy cows. The efficacy of indirect mastitis tests for diagnosis of the subclinical mastitis was determined by comparing results of mastitis tests with bacteriological findings. The experiment was conducted on two dairy farms (farm A and farm B) Holstein - Friesian breed. A total of 245 quarter milk samples were examined, 95 quarter milk samples with the California mastitis test from farm A and 150 quarter milk samples with the Draminski mastitis test from farm B. A quarter milk samples for bacteriological analysis were taken aseptically during the morning milking in sterile test tubes. On farm A, bacteria growth has not been detected in 46.32% (44/95) quarter milk samples, while on farm B negative bacteriological findings have been found in 50.67% samples (76/150). In present study, sensitivity of the California mastitis test (78.57%) is higher than sensitivity of the Draminski mastitis test (74.32%). The specificity of the California mastitis test and the Draminski mastitis test is 82.05% and 30.26%, respectively. Efficacy of the California mastitis test in detection of the subclinical mastitis in dairy cows is better than that of the Draminski mastitis test, since accuracy of the California mastitis test has been higher.


2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Asmita Shrestha ◽  
Rebanta Kumar Bhattarai ◽  
Himal Luitel ◽  
Surendra Karki ◽  
Hom Bahadur Basnet

Abstract Background The threat of methicillin-resistant Staphylococcus aureus (MRSA) exists globally and has been listed as a priority pathogen by the World Health Organization. One of the sources of MRSA emergence is livestock and its products, often raised in poor husbandry conditions. There are limited studies in Nepal to understand the prevalence of MRSA in dairy animals and its antimicrobial resistance (AMR) profile. A cross-sectional study was conducted in Chitwan, one of the major milk-producing districts of Nepal, from February 2018 to September 2019 to estimate the prevalence of MRSA in milk samples and its AMR profile. The collected milk samples (n = 460) were screened using the California Mastitis Test (CMT) and positive samples were subjected to microbiological analysis to isolate and identify S. aureus. Polymerase Chain Reaction (PCR) was used to identify the presence of the mecA gene and screen for MRSA. Results In total, 41.5% (191/460) of milk samples were positive in the CMT test. Out of 191 CMT positive milk samples, the biochemical tests showed that the prevalence of S. aureus was 15.2% (29/191). Among the 29 S. aureus isolates, 6.9% (2/29) were identified as MRSA based on the detection of a mecA gene. This indicates that that 1.05% (2/191) of mastitis milk samples had MRSA. The antibiotic sensitivity test showed that 75.9% (22/29) and 48.3% (14/29) S. aureus isolates were found to be sensitive to Cefazolin and Tetracycline respectively (48.3%), whereas 100% of the isolates were resistant to Ampicillin. In total 96.6% (28/29) of S. aureus isolates were multidrug-resistant (MDR). Conclusions This study revealed a high prevalence of S. aureus-mediated subclinical mastitis in dairy herds in Chitwan, Nepal, with a small proportion of it being MRSA carrying a mecA gene. This S. aureus, CoNS, and MRSA contaminated milk poses a public health risk due to the presence of a phenotype that is resistant to very commonly used antibiotics. It is suggested that dairy herds be screened for subclinical mastitis and treatments for the animals be based on antibiotic susceptibility tests to reduce the prevalence of AMR. Furthermore, future studies should focus on the Staphylococcus spp. to explore the antibiotic resistance genes in addition to the mecA gene to ensure public health.


2020 ◽  
Author(s):  
Erick Vitus Komba ◽  
Isaac Pastory Kashoma

Abstract Background: Three dairy farms were investigated for occurrence of retained placenta and subclinical mastitis, and the economic impacts attributable to the conditions. Reproductive performance data from 1169 calvings of dairy cows for five consecutive years spanning from 2014 to 2018 were used in this study. A total of 167 cows were screened with the California Mastitis Test (CMT), and udder quarters with CMT score of ≥ 3 (scale 1–5) were milk sampled for culture and final bacteriological identification. Results: Overall prevalences of subclinical mastitis and retained fetal membranes were 35.93% and 10.35%, respectively. The prevalence of bacterial isolates at animal level was 38.92%. Individual bacteria prevalence rates were 66.15% for Staphylococcus aureus, 13.85% for Escherichia coli, 6.15% for Bacillus spp., 6.15% for Streptococcus agalactiae and 7.69% for none typed microorganisms. Overall loss from subclinical mastitis was estimated at 10,603,800/= Tanzanian shillings (Tshs) equivalent to USD $ 4,700 with major losses (81.75%) attributable to the production loss followed by treatment expenditure (18.25%). Average loss attributed to mastitis per quarter was estimated at 49,320/= Tshs (USD $21.5). Retained placenta resulted in an increase (P<0.05) in the period from parturition to conception (148.7 vs. 96.0 days), number of services per conception (2.9 vs. 1.9) and calving interval (434.7 vs. 374.0 days). Conclusion: These findings point out to the economic importance of subclinical mastitis and retained fetal membranes in the dairy industry. This calls for improved milking hygiene, proper attention to health of mammary glands, regular screening tests and application of biosecurity measures as intervention strategies to lower the prevalence of subclinical mastitis and minimize the spread of pathogens in dairy farms. Since retained fetal membrane is an important problem causing great economic losses, appropriate control measures have to be instituted including cow comfort, proper immunization and careful nutritional management (mineral supplementation), particularly during the transition period.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3431 ◽  
Author(s):  
Woranich Hinthong ◽  
Natapol Pumipuntu ◽  
Sirijan Santajit ◽  
Suphang Kulpeanprasit ◽  
Shutipen Buranasinsup ◽  
...  

Subclinical mastitis is a persistent problem in dairy farms worldwide. Environmental Escherichia coli is the bacterium predominantly responsible for this condition. In Thailand, subclinical mastitis in dairy cows is usually treated with various antibiotics, which could lead to antibiotic resistance in bacteria. E. coli is also a reservoir of many antibiotic resistance genes, which can be conveyed to other bacteria. In this study, the presence of E. coli in milk and water samples was reported, among which enteropathogenic E. coli was predominant, followed by enteroaggregative E. coli and enterohemorrhagic E. coli, which was found only in milk samples. Twenty-one patterns of antibiotic resistance were identified in this study. Ampicillin- and carbenicillin-resistant E. coli was the most common among the bacterial isolates from water samples. Meanwhile, resistance to ampicillin, carbenicillin, and sulfamethoxazole-trimethoprim was the pattern found most commonly in the E. coli from milk samples. Notably, only the E. coli from water samples possessed ESBL phenotype and carried antibiotic resistance genes, blaTEM and blaCMY-2. This indicates that pathogenic E. coli in dairy farms is also exposed to antibiotics and could potentially transfer these genes to other pathogenic bacteria under certain conditions.


Author(s):  
SMMR Sumon ◽  
MA Ehsan ◽  
MT Islam

Subclinical mastitis is an economically important disease of dairy cows and has a prominent place amongst the factors that limit milk production. This study was undertaken to determine the association of somatic cell counts (SCC) and occurrence of bacteria with SCM in smallholder dairy cows in Mymensingh, Bangladesh. A total number of 240 quarters milk samples from apparently healthy lactating cows were subjected to SCC using NucleoCounter® SCC-100 ™ (Chemo Metec). A quarter was considered SCM positive if the quarter had SCC>100 x 103 cells/ml. All subclinical mastitis positive quarter milk samples were subjected to bacteriological examination and isolates were classified into major, minor, uncommon and mixed pathogens. The overall quarter-level prevalence of subclinical mastitis of dairy cows in Mymensingh district was 25% (95% CI, 19.52% to 30.48%). The most frequently isolated bacterial species were Staphylococcus aureus (18.33%) followed by coagulase-negative staphylococci (10%), Enterobacter spp. (6.67%), Escherichia coli (5%), Bacillus spp. (5%) and Pseudomonas aeruginosa (5%). Different bacterial isolates were associated with 90% cases of subclinical mastitis as mono infections or mixed infections. Mono and mixed infections significantly influenced SCC and were the most prominent factors responsible for increasing SCC. Mean SCC was the highest for Bacillus spp. (713.67 x 103 cells/ml) followed by Enterobacter spp. (395.75 x 103 cells/ml), Escherichia coli (386.00 x 103 cells/ml), Staphylococcus aureus (373.82 x 103 cells/ml), coagulase-negative staphylococci (182.67 x 103 cells/ml) and Pseudomonas aeruginosa (138.67 x 103 cells/ml). Major pathogens induced higher SCC (380.72 x 103cells/ml) than minor and other pathogen groups.J. Bangladesh Agril. Univ. 15(2): 266-271, December 2017


2016 ◽  
Vol 19 (3) ◽  
pp. 639-646 ◽  
Author(s):  
I. Klimiene ◽  
M. Virgailis ◽  
A. Pavilonis ◽  
R. Siugzdiniene ◽  
R. Mockeliunas ◽  
...  

AbstractThe objectives of this study were to determine the prevalence and antimicrobial resistance of coagulase-negative staphylococci (CNS) isolated from dairy cows with subclinical mastitis. Antimicrobial resistance in staphylococci were evaluated by breakpoint values specific to the species (EU-CAST). The presence of resistance-encoding genes was detected by multiplex PCR. A total of 191 CNS isolates were obtained. The CNS isolates were typically resistant to penicillin (67.4%), tetracyc-line (18.9%), and erythromycin (13.7%). CNS isolates (78.0%) were resistant to at least one antimicrobial compound, and 22.0% were multiresistant. The multiresistant isolates were predominantlyStaphylococcus chromogenes(28.6%),Staphylococcus warneri(19%) andStaphylococcus haemolyticus(14.3%). According to MIC pattern data, multiresistant isolates showed the highest resistance (p<0.05) rates to penicillin (85.7%), tetracycline (66.7%), and erythromycin (48.2%), but all of them were sensitive to daptomycin, oxacillin, qiunupristin/dalfopristin, and vancomycin.S. chromogenes (9.5%),S. haemolyticus(4.8%), andS. capitis ss capitis(2.4%) strains were resistant to methicillin; their resistance to oxacillin and penicillin was more than 8 mg/l. A high rate of resistance to penicillin was linked to ablaZ gene found in 66.6% of the isolated multiresistant CNS strains. Resistance to tetracycline via thetetK (38.1%) gene and penicillin via themecA (23.8%) gene were detected less frequently. GenemsrAB was responsible for macrolides and lincosamides resistance and detected in 28.6% of the CNS isolates. Antimicrobial resistance genes were identified more frequently inS. epidermidis,S. chromogenes, andS. warneri.


2020 ◽  
Vol 13 (6) ◽  
pp. 1193-1198
Author(s):  
Rania M. Ewida ◽  
Amira A. T. Al-Hosary

Background and Aim: Milk production is one of the main props for the national economy. One of the crucial problems in this industry is subclinical mastitis, which harms this industry that considered the backbone of the economy. It is an infectious and zoonotic disease; the infection can spread between dairy animals through milkers' hands, and milking machines, while the human infection occurs due to the consumption of apparently hygienic milk. Staphylococcus aureus is one of the main causative agents of clinical and subclinical mastitis. It is also considered one of the bacteria incriminated in food intoxication of humans due to its virulence factors as enterotoxins and toxic shock syndrome. The current study was designed to assess the prevalence of S. aureus and its enterotoxins, as well as, its other virulence factors in milk collected from cows that suffer from subclinical mastitis. Materials and Methods: Sixty cows were collected from different dairy farms located in Assiut Governorate, Egypt. These cows were subjected to the clinical examination of the udder and its lymph nodes before sampling. Milk samples were collected from clinically healthy udders. All the milk samples were examined by California mastitis test (CMT), polymerase chain reaction (PCR), and enzyme-linked immunosorbent assay (ELISA) for confirmation subclinical mastitis, presence of S. aureus and its enterotoxins genes and other virulence factors in the examined milk samples. Results: The cows included in the current study had healthy udders. The sixty collected milk samples were tested by CMT. 48/60 (80.0%) were positive samples; from the 48 positive samples, 46 (95.83%) samples were confirmed positive by S. aureus 16s rRNA PCR assay. Multiplex PCRs confirmed the presence of staphylococcus enterotoxin gene C (sec) in one sample, staphylococcus enterotoxin gene D (sed) in 23 samples, while ELISA assay confirmed the presence of the same enterotoxin in only two samples. On the other hand, other groups of genes responsible for some other virulence factors of S. aureus like the extracellular thermostable nuclease (nuc) gene were found in 33 samples, while toxic shock syndrome (tsst) gene and methicillin restraint S. aureus (mecA) gene were not detected in this study. Conclusion: Subclinical mastitis is one of the hidden factors that adversely affect the health of both animals and humans. The milk is usually appeared good and may be consumed by humans especially children; however, it causes severe public health problems. In addition, the infected animals with this form of mastitis can spread the infection to other dairy animals and may be turned to a clinical case of contagious mastitis that may be ended by animal culling or death. S. aureus is one of the main causes of subclinical mastitis in cattle. In addition to extracellular thermostable nuclease (nuc) gene, staphylococcus enterotoxin gene C (sec) and staphylococcus enterotoxin gene D (sed) are the most common virulence genes confirmed in subclinical mastitis milk. These results highlighted the need to apply more hygienic measures in the dairy farms to avoid spreading the infection between animals to ensure the production of safe and healthy food to humans.


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