Risk from Staphylococcus aureus in informally marketed raw cow milk

2019 ◽  
Vol 2 (1) ◽  
pp. 74 ◽  
Author(s):  
Desislava Bangieva ◽  
Valentin Rusev

This study aimed to investigate the presence of Staphylococcus spp. and Staphylococcus aureus in raw cow milk samples taken from peddlers of five regions in Bulgaria. The results showed that all 44 samples tested were positive for Staphylococcus spp. All isolates were tested for coagulase production and subjected to PCR analysis. PCR amplification of 16S rRNA and nuc genes found the presence of Staphylococcus aureus in 23 (52.3%) of a total of 44 raw milk samples. The number of Staphylococcus spp. ranged from 3x102 to 1.08x106 cfu/ml, and that of Staphylococcus aureus from 1.5x102 to 3.19x105 cfu/ml. It is concluded that control over the hygiene of handling and processing raw milk is essential for its safety.

2019 ◽  
Vol 42 ◽  
pp. e45231
Author(s):  
Camila Lampugnani ◽  
Maike Taís Maziero Montanhini ◽  
Maria Emilene Martino Campos‐Galvão ◽  
Luis Augusto Nero ◽  
Luciano dos Santos Bersot

This study aimed to isolate Staphylococcus aureus in refrigerated raw cow milk, and identify the presence of enterotoxin-expression genes, enterotoxin production and adherence ability, and antimicrobial resistance potential of the isolated strains. Fifty raw milk samples obtained in different dairy farms were analyzed for S. aureus and evaluated in the isolates the presence of genes associated with the production of major staphylococcal enterotoxins and biofilm formation. In vitro assays were also performed to evaluate the production of enterotoxins and adherence ability, and the antimicrobial resistance. One half (25/50) of raw milk samples presented coagulase-positive staphylococci and 95.2% of the isolates were confirmed to be S. aureus. Among them, 42.4% were carrying genes for enterotoxins production; however, only one isolate was able to produce enterotoxins. All S. aureus isolates were carrying at least two genes associated with biofilm formation and 95.2% isolates was able to adhere upon the in vitro assay. All isolates demonstrated antimicrobial resistance potential to one or more of the tested antibiotics.


2017 ◽  
Vol 7 (1) ◽  
pp. 21-27
Author(s):  
Ahmed Reda Belmamoun ◽  
Abdelkader Ammam ◽  
Imene Berrabah ◽  
Karima Bereksi Reguig

The study was conducted to identify and characterize Staphylococcus aureus in raw milk derived from subclinical mastitis in Sidi-Bel-Abbes Algeria. In this paper, we explore the possibility of detection of the coagulase gene (coa), which encodes the coagulase enzyme, by PCR analysis in antibiotic-resistant isolates, with the latex agglutination phenotype and free coagulase.Out of 336 samples of raw milk examined with California mastitis test (CMT) posi-tive; a total of 142 samples were bacteriologically positive with 56.34% Staphylococcus isolates, 21 (26.25%) isolates were confirmed as S.aureus. Nineteen (90.48%) isolates of S.aureus showed free coagulase on the tube agglutination test. Two atypical S.aureus strains (9.52%) were defective for the clumping factor and / or protein A , determined with the Staphytect plus test and the tube coagulase test. The isolates of S.aureus were resistant to penicillin and tetracycline with 76.19%. Two isolates (9.52%) of S.aureus re-sistant to meticillin (MRSA) were detected in this study, with a MIC of ≥4 μg / liter and a cefoxitin screen test with a MIC of ≥8 μg / liter, and 13 (61.9%) isolates were with a multiresistance phenotype. The 21 isolates were sub-jected to PCR amplification of the 3' end of the coa gene, 18 (85.71%) were revealed on a 1% agarose gel with a single band between 547 bp and 875 bp. The use of the PCR genotypic test to identify the profile of the coa gene can be used as an appropriate identification criterion for differentiating coagulases from S.aureus and for understanding their epidemiology.


2018 ◽  
Vol 12 (07) ◽  
pp. 533-541 ◽  
Author(s):  
Walid Elmonir ◽  
Etab Abo-Remela ◽  
Azza Sobeih

Introduction: Milk is an important food in Egypt and most of it is sold as raw milk in informal markets. Methodology: This study was conducted to investigate the public health risks of Escherichia coli and Staphylococcus aureus in milk sold in informal markets in Egypt. A total of 121 milk samples were analyzed for occurrence, virulence genes and antibiotic resistance of E. coli and S. aureus. Results: A total of 35/121 (28.9%) of milk samples were contaminated with 16/121 (13.2%) E. coli, 22/121 (18.2%) S. aureus, and 3/121 (2.5%) both isolates. Shiga-toxin producing E. coli (STEC), Enterotoxigenic E. coli (ETEC) and Enterotoxigenic S. aureus were detected in 5/121 (4.1%), 2/121 (1.7%) and 8/121 (6.6%) of the examined milk samples, respectively. Multiple drug resistances (MDRs) were showed by 14/16 (87.5%) and 21/22 (95.5%) of E. coli and S. aureus isolates, respectively. E. coli isolates showed high resistance for cephalothin (87.5%), ampicillin (68.8%) and tetracycline (68.8%), but were sensitive for gentamicin and chloramphenicol. Resistance phenotypes of E. coli were diverse; however, STEC isolates were significantly associated with co-resistance to cephalothin, ampicillin and tetracycline (P< 0.05). Two (9.1%) of S. aureus isolates were methicillin-resistant (MRSA) but sensitive to gentamicin (GS-MRSA). Five (22.7%) of S. aureus isolates were gentamicin-resistant methicillin-sensitive S. aureus (GR-MSSA). S. aureus isolates also showed high resistance for ampicillin (100%), tetracycline (90.1%) and sulfamethoxazole-trimethoprim (90.1%). Conclusion: These findings highlighted the potential public health hazards of E. coli and S. aureus pathogens in raw milk sold in informal markets in Egypt.


2020 ◽  
Vol 8 (3) ◽  
pp. 82-86
Author(s):  
Shyamala Rai ◽  
Barsha Karki ◽  
Sujita Humagain ◽  
Sandesh Rimal ◽  
Sandhya Adhikari ◽  
...  

The emergence of antibiotic resistance in microorganisms and the presence of such isolates in milk pose a great risk to public health. Therefore, this study aims to determine the antibiotic susceptibility pattern of Escherichia coli and Staphylococcus aureus isolated from milk and assess the microbial quality of milk. For this, a total of 70 milk samples were collected and the total bacterial count (TBC) was determined. E. coli and S. aureus were isolated using their respective selective media while antibiotic susceptibility testing was carried out by Kirby Bauer Disc Diffusion method. The TBC showed that the raw milk samples contained two-fold higher microbial load while the pasteurized milk samples contained four-fold higher microbial loads than the standard guidelines. A total of 62 isolates were identified from culture-positive milk samples of which 32 were E. coli and 30 were S. aureus. A significant correlation was observed between microbial load and the organism isolated (r = 0.339, p<0.01). All S. aureus isolates were susceptible to Chloramphenicol while 40% were resistant to Cefoxitin, indicating the presence of Methicillin resistant S. aureus (MRSA). Also, 12 multidrug resistant (MDR) S. aureus were identified. While for E. coli, all were susceptible to Chloramphenicol but resistant to Ampicillin. Also, 9 MDR E. coli were detected. Higher resistance was observed among isolates from the raw milk samples than the pasteurized milk. It can be concluded that the milk produced by small-scale farms and dairy industries of Kathmandu district are of poor quality. Hence, routine microbial quality assessment and antimicrobial resistance monitoring should be followed to safeguard public health.


2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaomeng Kou ◽  
Huixue Cai ◽  
Shudi Huang ◽  
Yongqing Ni ◽  
Baolong Luo ◽  
...  

Staphylococcus aureus is one of the main pathogens causing mastitis in dairy animals worldwide. It is an important opportunistic pathogen of raw milk, and the enterotoxin causes significant food poisoning. Monitoring the antibiotic resistance of S. aureus in raw milk is helpful for a risk assessment of S. aureus. In this study, 62 strains (43.1%) of S. aureus were isolated from 144 retail raw milk samples of different varieties from four regions in northern Xinjiang, China. Among them, the isolation rates at Shihezi, Hami, Altay, and Tacheng were 58.1% (54/93), 12.9% (4/31), 18.2% (2/11), and 22.2% (2/9), respectively. The isolation rate of positive strains in cow milk samples was the highest (61.7%, 37/60), followed by camel milk (35.9%, 23/64), and horse milk (10.0%, 2/20). The results of the classical virulence genes test showed that 12.9% (8/62) of the isolates carried at least one virulence gene. The main genotype was see (6.5%, 4/62), followed by sea+sec (3.2%, 2/62), sea (1.6%, 1/62), and sec (1.6%, 1/62). The analysis of 13 resistance genes and the susceptibility to 12 different antibiotics of 62 isolates showed that 80.6% (50/62) of the strains were resistant to at least one antibiotic, and 46.8% (29/62) were resistant to three or more antibiotics. The isolated strains had the highest resistance rate to penicillin (72.6%, 45/62), and 25.8% (16/62) of the isolates carried the blaZ resistance gene. In addition, 32 strains (51.6%, 32/62) of methicillin-resistant S. aureus were detected. All isolates had the ability to form biofilms. The pulsed-field gel electrophoresis results showed that the 47 isolates revealed 13 major pulsotypes (P1–P13) and 26 subtypes with 80% similarity, indicating the overall genetic diversity in the distribution area and sources of the samples. These findings indicate that S. aureus causes serious pollution of raw milk in northern Xinjiang, which has a negative effect on public health. Therefore, control measures and continuous monitoring should be undertaken to ensure the quality and safety of raw milk.


Mljekarstvo ◽  
2021 ◽  
pp. 248-256
Author(s):  
Erinda Lika ◽  

This research aimed to determine the prevalence rate of antimicrobial resistance (AMR) of Staphylococcus aureus isolated from raw cow milk samples in Albania and Serbia. A total of 100 raw milk samples, 50 from Albania and 50 from Serbia, have been collected from randomly selected cattle farms. Twelve samples (12 %) were positive for S. aureus, five of those originating from Albania (41.66 %) and seven from Serbia (58.33 %). Resistance of isolated S. aureus strains to ampicillin in milk samples from Albania (36.7 %) and Serbia (34.1 %) was the most common. Some of S. aureus strains from milk samples from Albania were resistant to tetracycline (16.9 %), while isolates from milk samples from Serbia were more resistant towards oxacillin (18 %). The recorded resistance towards erythromycin (13.2 %; 13.1 %), and sulfatrim (7.6 %; 6.9 %) was similar between both milk samples, respectively. The obtained results have shown higher resistance of S. aureus strains towards cephalothin in milk samples from Serbia (3.9 %) compared to milk samples from Albania (1.6 %), respectively. All isolates tested for antibiotic sensitivity were susceptible to methicillin, vancomycin, chloramphenicol, and ciprofloxacin. The obtained results regarding the minimum inhibitory concentrations (MICs) of antibiotics indicated that isolates were resistant to tetracycline, oxacillin, erythromycin, and ampicillin, respectively. Results of our investigation have shown that the found antibiotics residues are related to the usage of erythromycin (72.6 % and 73.9 %), followed by ampicillin (70.4 % and 71.2 %) while residues of ciprofloxacin in the analysed milk samples was not registered.


Author(s):  
Khondaker Wahid Hasan ◽  
Nourin Tarannum ◽  
Sahana Parveen

The increase of pathogens in milk is threatening for the human beings. This is an investigation on overall microbiological analysis of raw and pasteurized milk as well as the milk-based beverages and also determining the antibiotic resistance pattern of isolated Escherichia coli and Staphylococcus aureus. A total of 100 samples (raw milk, pasteurized milk, mattha, lassi and laban) were taken from various locations of the capital city of Bangladesh, Dhaka. Total Viable Count, Total Coliform Count and Yeast and Moulds Count were performed as the microbiological inspection of selected samples. E.coli and Staphylococcus aureus were identified by conducting morphological analysis, gram-staining and biochemical tests. Antibiotic resistance pattern of isolated Escherichia Coli and Staphylococcus aureus were also detected with 11 commonly used antibiotics by conducting disc-diffusion method, following the CLSI guideline. The TVC range was the highest in raw milk samples (3.8×104 – 4.1×108 cfu/ml), and the lowest in pasteurized milk samples (1.2×102 – 5.4×103 cfu/ml), while 70% raw milk and 10% pasteurized milk samples strains were above the acceptable limit of Food and Drug Administration (FDA). Thirty-six Escherichia coli and thirty-two Staphylococcus aureus were isolated from all the 100 milk and milk-based beverage samples. The isolated Escherichia coli strains were most resistant to Penicillin G (81.58%), Erythromycin (78.94%) and Ampicillin (73.68%), and isolated Staphylococcus aureus strains were most resistant to Penicillin G (90.62%), Ampicillin (81.25%) and Methicillin (71.87%). respectively. Public awareness is needed to reduce the redundant use of antibiotics.


2020 ◽  
Vol 8 (3) ◽  
pp. 368 ◽  
Author(s):  
Alexandre J. Kennang Ouamba ◽  
Gisèle LaPointe ◽  
Simon Dufour ◽  
Denis Roy

The temporal instability of raw milk microbiota drastically affects the reliability of microbiome studies. However, little is known about the microbial integrity in preserved samples. Raw cow milk samples were preserved with azidiol or bronopol and stored at 4 °C, or with dimethyl sulfoxide (DMSO) or a mixture of azidiol and DMSO and stored at −20 °C for up to 30 days. Aliquots of 5-, 10-, and 30-day post-storage were treated with propidium monoazide (PMA), then analyzed by sequencing the 16S rRNA gene V3-V4 and V6-V8 regions. The V6-V8 gave a higher richness and lower diversity than the V3-V4 region. After 5-day storage at 4 °C, the microbiota of unpreserved samples was characterized by a drastic decrease in diversity, and a significant shift in community structure. The treatment with azidiol and DMSO conferred the best community stabilization in preserved raw milk. Interestingly, the azidiol treatment performed as well for up to 10 days, thus appearing as a suitable alternative. However, neither azidiol nor bronopol could minimize fungal proliferation as revealed by PMA-qPCR assays. This study demonstrates the preservative ability of a mixture of azidiol and DMSO and provides deeper insights into the microbial changes occurring during the cold storage of preserved raw milk.


2020 ◽  
Vol 18 (1) ◽  
pp. 1-12
Author(s):  
A. Yakubu ◽  
I.O Abdullahi ◽  
C.Z. Whong ◽  
B. Olayinka

This study determined the prevalence and antibiotic susceptibility profile of Staphylococcus aureus isolated from milk and milk products in Nasarawa State, Nigeria. A total of 180 samples comprising of fresh raw milk, bulk milk, Nono, and Kindirmo were collected over a period of 6 months. Standard microbiological procedures were employed in the isolation, identification, characterization and determination of the antibiogram of S. aureus from the milk samples. Characterization was achieved by morphological, biochemical characteristics using conventional methods and Microgen® STAPH-ID kits. The isolates were tested for susceptibility or resistance to a panel of 11 commonly used antibiotics using the agar disc diffusion technique. Out of the 180 milk samples examined, nine (9) S. aureus were isolated giving a prevalence of 5.0%. The occurrence of S. aureus was higher in Nono (12.1%) and Kindirmo (10.6%) than in fresh raw milk (5.9%). The kind of water (well water) used for cleaning utensils at the Nono and Kindirmo selling points was found to be a risk factor associated with the occurrence of S. aureus in the products. All of the isolates were resistant to cefoxitin (100%), ampicillin (100%), and amoxicillin/clavulanic acid (100%). The isolates displayed various rates of resistance to erythromycin (22.2%), sulphamethoxazole/trimethoprim (22.2%), and tetracycline (44.4%). Five (5) antibiotic resistance patterns were recorded among the isolates an indication of different levels of use and misuse of antibiotics in the areas studied. The detection of Staphylococcus aureus in fresh and fermented milk in the areas studied suggests that consumption of dairy products especially those produced using traditional methods, constitute a hazard to consumers. It is recommended that since compliance with basic hygiene requirements is not guaranteed, hazard analysis and critical control points (HACCP) concepts should be seen as a part of an effective total hygiene concept at the selling points. Keywords: Antibiotic susceptibility profile, Milk, Nasarawa State, Nigeria, Prevalence, Staphylococcus aureus


2018 ◽  
Vol 38 (8) ◽  
pp. 1577-1583 ◽  
Author(s):  
José C. Ribeiro Júnior ◽  
Pedro I. Teider Junior ◽  
André L.M. Oliveira ◽  
Edson A. Rios ◽  
Ronaldo Tamanini ◽  
...  

ABSTRACT: Pseudomonas, the main genus of gram-negative microorganisms isolated from milk, is psychrotrophic, biofilm-forming, and thermo-resistant deteriorating enzyme producers. The aim of this study was to quantify Pseudomonas spp. in goat’s and cow’s milk produced in the Paraná state, Brazil, to evaluate the deteriorating activity of the isolates at mesophilic and psychrotrophic conditions and to identify, at the species level, the isolates with alkaline metalloprotease (aprX gene) production potential. Microbiological, biochemical and molecular methods were used for isolating, confirming and identifying of isolates. The mean counts were 1.6 (±6.3)x104 and 0.89(±3)x102 CFU/mL for goat and bovine milk samples, respectively, immediately after milking. Of the Pseudomonas colonies isolated from goat milk (n=60), 91.7% showed proteolytic potential when incubated at 35°C/48 h and 80% at 7°C/10 days, and lipolytic potential was observed in 95% of the isolates incubated in mesophilic and 78.3% at refrigeration conditions. From the isolates of bovine milk (n=20), 35% showed proteolytic activity only when incubated at 35°C/48 h, and lipolytic potential was observed in 25% of the isolates incubated at 7°C/10d and 35°C/48h. It was observed that 83.3% and 25% of the isolates genetically confirmed as Pseudomonas spp. of goat and bovine milk showed the potential for alkaline metalloprotease production, with the species P. azotoformans, P. koreensis, P. gessardii, P. monteilii and P. lurida being the most frequent in goat milk and P. aeruginosa the only species identified in cow milk.


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