Prevalence and Characteristics of Staphylococcus aureus Isolated From Retail Raw Milk in Northern Xinjiang, China

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.

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Enterotoxins production, biofilm formation and antimicrobial resistance of Staphylococcus aureus strains isolated from refrigerated raw cow milk

Acta Scientiarum Technology ◽

10.4025/actascitechnol.v42i1.45231 ◽

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

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Resistance ◽

Biofilm Formation ◽

Raw Milk ◽

Cow Milk ◽

In Vitro Assays ◽

Vitro Assay ◽

Milk Samples ◽

Adherence Ability

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.

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Risk from Staphylococcus aureus in informally marketed raw cow milk

Food Science and Applied Biotechnology ◽

10.30721/fsab2019.v2.i1.67 ◽

2019 ◽

Vol 2 (1) ◽

pp. 74 ◽

Cited By ~ 1

Author(s):

Desislava Bangieva ◽

Valentin Rusev

Keyword(s):

Staphylococcus Aureus ◽

16S Rrna ◽

Pcr Amplification ◽

Raw Milk ◽

Cow Milk ◽

Pcr Analysis ◽

Milk Samples ◽

Staphylococcus Spp ◽

And Staphylococcus Aureus

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.

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Occurrence of Enterotoxic Staphylococcus aureus in Raw Milk from Yaks and Cattle in Mongolia

Journal of Food Protection ◽

10.4315/0362-028x-70.7.1726 ◽

2007 ◽

Vol 70 (7) ◽

pp. 1726-1729 ◽

Cited By ~ 8

Author(s):

URANCHIMEG TSEGMED ◽

GIOVANNI NORMANNO ◽

MARIT PRINGLE ◽

KAREL KROVACEK

Keyword(s):

Staphylococcus Aureus ◽

Dairy Products ◽

Food Poisoning ◽

Raw Milk ◽

Latex Agglutination ◽

Animal Origin ◽

Foodborne Illnesses ◽

First Report ◽

Milk Samples ◽

Milk And Dairy Products

Staphylococcal food poisoning is considered one of the leading foodborne illnesses in humans worldwide and is associated with contaminated foods of animal origin, such as milk and dairy products. In this study, we investigated the occurrence of staphylococci and the enterotoxigenic properties of Staphylococcus aureus isolated from raw milk from yaks (Bos mutus) and cattle in Mongolia. Staphylococci were isolated from 72 (74%) of the 97 raw milk samples. Of the samples containing staphylococci, 69% (50 of 72) were from yaks and 30.5% (22 of 72) were from cattle. S. aureus was detected in 10% of yak (7 of 72) and 21% of cattle (15 of 72) milk samples. Staphylococcal enterotoxin C was detected in 23% (5 of 22) of the S. aureus strains investigated, based on the reverse passive latex agglutination technique. Three of the five enterotoxigenic strains were from yaks and two were from cattle. None of the S. aureus strains tested produced staphylococcal enterotoxins A, B, or D. To our knowledge, this is the first report of the occurrence of staphylococci and enterotoxigenic S. aureus in milk from yaks and cattle in Mongolia.

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Methicillin-Resistant Staphylococcus aureus (MRSA) in Artisanal Cheeses in México

International Journal of Microbiology ◽

10.1155/2018/8760357 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6 ◽

Cited By ~ 4

Author(s):

Roberto Adame-Gómez ◽

Jeiry Toribio-Jimenez ◽

Amalia Vences-Velazquez ◽

Elvia Rodríguez-Bataz ◽

Maria Cristina Santiago Dionisio ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Methicillin Resistance ◽

Food Poisoning ◽

Raw Milk ◽

Cow Milk ◽

Dot Blot ◽

Mannitol Salt Agar ◽

Methicillin Resistant ◽

Dairy Foods ◽

Dot Blot Analysis

Milk and dairy foods have frequently been implicated in staphylococcal food poisoning, and contaminated raw milk is often involved. The aim of the study was to determine the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) in raw cow milk cheese produced in Mexico. A total of 78 unpasteurized cow milk cheese samples were screened for S. aureus. The isolates were identified as S. aureus based on morphology, Gram stain, catalase test, coagulase test, and mannitol salt agar fermentation. Isolates were subjected to biotyping, the methicillin resistance was analyzed using the disk diffusion, and the Staphylococcus enterotoxin A (SEA) production was examined by a dot-blot analysis. From a total of 78 samples of unpasteurized cheeses analyzed in this study, 44 cheeses were positive for S. aureus; however, a differential contamination between the different types of cheeses was observed, with high risk of contamination in adobero cheese (12, 95% CI 1.75 to 94.20; p=0.002). In this study, the frequency of methicillin-resistant Staphylococcus aureus (MRSA) was 18.1% (8/44) and of enterotoxin A producers was 18.1% (8/44). When classified by biotypes, MRSA only belongs to the human ecovar biotype (2/8, 25%) and the D biotype (4/8, 50%). S. aureus producers of enterotoxin A were distributed in specific nonhost biotypes.

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Antimicrobial resistance of Staphylococcus aureus strains isolated from cow raw milk samples from Albania and Serbia

Mljekarstvo ◽

10.15567/mljekarstvo.2021.0404 ◽

2021 ◽

pp. 248-256

Author(s):

Erinda Lika ◽

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Resistance ◽

Prevalence Rate ◽

Antibiotic Sensitivity ◽

Raw Milk ◽

Cow Milk ◽

Milk Samples ◽

Minimum Inhibitory Concentrations ◽

Antibiotics Residues ◽

Cattle Farms

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.

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Production of Staphylococcus aureus Enterotoxin A in Raw Milk at High Temperatures

Journal of Food Protection ◽

10.4315/0362-028x.jfp-13-527 ◽

2014 ◽

Vol 77 (9) ◽

pp. 1612-1616 ◽

Cited By ~ 12

Author(s):

I. I. SABIKE ◽

H. FUJIKAWA ◽

M. Z. SAKHA ◽

A. M. EDRIS

Keyword(s):

Staphylococcus Aureus ◽

High Temperatures ◽

Elevated Temperatures ◽

Food Poisoning ◽

Raw Milk ◽

The Other ◽

Milk Samples ◽

Natural Microflora ◽

Processing And Storage ◽

And Storage

Improper processing and storage of raw milk contaminated with Staphylococcus aureus at elevated temperatures can result in the production of staphylococcal enterotoxins, especially type A (SEA), which is most frequently associated with food poisoning outbreaks such as the large one in Osaka, Japan, in 2000. In this study, the characteristics of S. aureus growth and SEA production at various high temperatures in raw milk samples were studied using two raw milk samples naturally containing low and high levels of natural microflora. The optimal temperatures found for SEA production in the two milk types were as high as 40 and 44°C (range, 36 to 48°C), and SEA production was dependent on the initial dose of S. aureus. These high temperatures were close to that of the outbreak in Japan. Thus, it was concluded that temperature was critical for SEA production in raw milk. It was also observed that natural microflora in the milk samples considerably suppressed SEA production but not staphylococcal growth. On the other hand, the amount of toxin in most milk samples decreased after peaking during storage.

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Pathogenic Potential and Antimicrobial Resistance Profile of Staphylococcus aureus in Milk and Beef from the Northwest and Southwest Regions of Cameroon

BioMed Research International ◽

10.1155/2020/6015283 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Marie Ebob Agbortabot Bissong ◽

Brandon Fonyuy Tahnteng ◽

Collins Njie Ateba ◽

Jane-Francis Tatah Kihla Akoachere

Keyword(s):

Staphylococcus Aureus ◽

Virulence Gene ◽

Raw Milk ◽

Cow Milk ◽

Animal Origin ◽

Diffusion Method ◽

Potential Hazard ◽

Disk Diffusion Method ◽

Cross Sectional ◽

Pathogenic Potential

Staphylococcus aureus is a major foodborne pathogen and commensal of the skin and mucous membranes of animals and humans. Its virulence relies on the production of a variety of toxins resistant to denaturing conditions. Increasing reports of S. aureus food poisoning and contamination of foods of animal origin elsewhere necessitates the investigation of these foods in Cameroon, to implement safety measures. This cross-sectional study evaluated S. aureus contamination in milk and beef in the Northwest and Southwest Regions of Cameroon, where cow milk is usually not pasteurized before consumption, and beef is the main source of protein. The distribution of antibiotic-resistant isolates and those with enterotoxin-producing potential was also investigated to provide data of public health and food safety benefit. S. aureus was isolated from 39 raw milk and 250 beef samples by standard methods. Confirmation of isolates was by PCR to detect the nuc gene. S. aureus was investigated for classical staphylococcal enterotoxin (SE) genes (sea, seb, sec, sed, and see) by PCR. Their susceptibility to 9 antibiotics was tested by the disk diffusion method. The chi-square test was used to compare the contamination of samples, antibiotic resistance, and the distribution of SE genes. S. aureus was isolated from 11.1% of samples. Contamination was higher in milk (48%) than in beef (5.2%) ( P < 0.001 ). The sea was the most frequently (90%) harboured gene. A large proportion of isolates (88%) harboured more than one virulence gene. Isolates were generally resistant to erythromycin (82%), vancomycin (80%), tetracycline (76%), and oxacillin (74%). Multidrug resistance (MDR) was common (92%). Milk and beef samples in study area were contaminated with MDR enterotoxigenic S. aureus strains and may constitute a potential hazard to consumers. Thus, the need for implementation of proper hygienic measures when handling these products and pasteurization of milk cannot be overemphasized.

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Phylogeny Characterization of Seb Gene Encoding Enterotoxins in Staphylococcus aureus Isolated from Raw Milk and Cheese

International Journal of Drug Delivery Technology ◽

10.25258/ijddt.v9i3.13 ◽

2019 ◽

Vol 9 (o3) ◽

Author(s):

Fatima N. Aziz ◽

Laith Abdul Hassan Mohammed-Jawad

Keyword(s):

Staphylococcus Aureus ◽

Food Poisoning ◽

Raw Milk ◽

Staphylococcal Enterotoxin B ◽

Human Pathogen ◽

Conventional Pcr ◽

Biochemical Tests ◽

Specific Primers ◽

Gene Encoding

Food poisoning due to the bacteria is a big global problem in economically and human's health. This problem refers to an illness which is due to infection or the toxin exists in nature and the food that use. Milk is considered a nutritious food because it contains proteins and vitamins. The aim of this study is to detect and phylogeny characterization of staphylococcal enterotoxin B gene (Seb). A total of 200 milk and cheese samples were screened. One hundred ten isolates of Staphylococcus aureus pre-confirmed using selective and differential media with biochemical tests. Genomic DNA was extracted from the isolates and the SEB gene detects using conventional PCR with specific primers. Three staphylococcus aureus isolates were found to be positive for Seb gene using PCR and confirmed by sequencing. Sequence homology showed variety range of identity starting from (100% to 38%). Phylogenetic tree analyses show that samples (6 and 5) are correlated with S. epidermidis. This study discovered that isolates (A6-RLQ and A5-RLQ) are significantly clustered in a group with non- human pathogen Staphylococcus agnetis.

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Prevalence and antibiotic susceptibility profile of Staphylococcus aureus from milk and milk products in Nasarawa State, Nigeria

Sokoto Journal of Veterinary Sciences ◽

10.4314/sokjvs.v18i1.1 ◽

2020 ◽

Vol 18 (1) ◽

pp. 1-12

Author(s):

A. Yakubu ◽

I.O Abdullahi ◽

C.Z. Whong ◽

B. Olayinka

Keyword(s):

Staphylococcus Aureus ◽

Antibiotic Susceptibility ◽

Hazard Analysis ◽

Raw Milk ◽

Fermented Milk ◽

Milk Products ◽

Milk Samples ◽

Critical Control Points ◽

Agar Disc ◽

Resistance Patterns

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

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Molecular Detection of Staphylococcal Enterotoxins and mecA Genes Products in Selected Food Samples Collected from Different Areas in Khartoum State

International Journal of Microbiology ◽

10.1155/2021/5520573 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

Mohammed Yahya Ahmed ◽

Hashim Abdalbagi Ali ◽

Babbiker Mohammed Taher Gorish ◽

Sara Omer Ali ◽

Eman Saif Aldein Abdalrhim ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Meca Gene ◽

Food Poisoning ◽

Meat Products ◽

Low Frequency ◽

Raw Milk ◽

Food Samples ◽

Increased Risk ◽

Enterotoxin B ◽

Staphylococcus Aureus Enterotoxins

Staphylococcal food poisoning is an intoxication that results from the consumption of improperly prepared or stored foods containing sufficient amounts of one or more preformed S. aureus enterotoxins. Nowadays, many researchers worldwide noted an emergence of resistant strains such as Staphylococci particularly for the antibiotic methicillin. Therefore, this study was aimed to determine the existence of Staphylococcus aureus and its enterotoxins, mecA genes, in selected food samples. A total of 400 selected food samples were collected from different areas in Khartoum State. The selected foods included cheese, meat products, fish, and raw milk. One hundred samples from each type of food were cultivated, and the resultant growth yielded 137 (34.25%) S. aureus, 126 (31.5%) bacteria other than S. aureus, and 137 (34.25%) yielded no growth. Eighty-four of the 137 S. aureus isolates were randomly selected and tested for the presence of mecA and enterotoxin genes. The oxacillin sensitivity test showed that 15 (11%) of 137 S. aureus isolates were oxacillin resistant. The PCR assay showed that the mecA gene was detected in 15 of 84 (17%) S. aureus isolates. Simultaneously, only 2 (2.385%) out of 84 S. aureus isolates showed an enterotoxin B gene product. There was a relatively moderate prevalence of methicillin-resistant Staphylococcus aureus with very low frequency of enterotoxin B gene in different kinds of selected food samples collected from Khartoum State. These findings elucidate the increased risk on public in Khartoum being affected by Staphylococcal food poisoning upon consumption of dairy or meat products prepared in unhygienic conditions that could lead to intoxication by Staphylococcus aureus enterotoxins.

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