Assessing and analysing contamination of a dairy products processing plant byStaphylococcus aureususing antibiotic resistance and PFGE

2000 ◽  
Vol 46 (12) ◽  
pp. 1108-1114 ◽  
Author(s):  
E C Tondo ◽  
MC M Guimarães ◽  
J AP Henriques ◽  
M AZ Ayub

A dairy product processing plant was studied for 2.5 years to examine contamination with Staphylococcus aureus and try to correlate the source of contamination. Cultures were submitted to an antibiotic susceptibility test (AST) and characterised by Pulsed-field Gel Electrophoresis (PFGE) analysis. Results showed that 35.2% (19/51) of food handlers were asymptomatic carriers of S. aureus, and that 90.4% (19/21) of raw milk sampled was contaminated. Staphylococcus aureus was isolated from only 10 samples among more than 3200 investigated dairy products. No S. aureus contamination was found on machinery. The AST analysis demonstrated sensitivity of tested S. aureus to oxacillin, cephalothin, vancomycin, gentamicin, and sulfamethoxazole/trimethoprim. AST analysis generated eight different phenotypic profiles, but did not allow us to identify the source of contamination in seven of ten final products. PFGE analysis proved to be a sensitive method as it generated 42 different DNA banding profiles among the 48 S. aureus investigated, demonstrating a lack of predominance of endemic strains in the plant, contrary to suggestions raised by antibiotic resistance typing. Based on PFGE genotyping, S. aureus strains isolated from four contaminated final products were similar to four S. aureus isolated from raw milk. Five final products contained S. aureus different from all other strains collected, and one showed similarity to a strain isolated from a food handler. These results suggest contamination by raw milk as the main source of contamination of the final dairy products.Key words: Staphylococcus aureus, dairy products, antibiotic susceptibility, PFGE.

2019 ◽  
Vol 6 ◽  
pp. 59-62
Author(s):  
Ranjana K.C. ◽  
Ganga Timilsina ◽  
Anjana Singh ◽  
Supriya Sharma

Objectives: To isolate methicillin resistant Staphylococcus aureus (MRSA) from anterior nares of dairy workers and dairy products and assess the antibiotic susceptibility pattern of the isolates. Methods: Swab samples collected from anterior nares of dairy workers and dairy product (butter) were inoculated into mannitol salt agar and incubated at 37ºC for 24 hours. Identification was done based on colony characteristics, Gram's staining, catalase, oxidase and coagulase test. Antibiotic susceptibility testing was done by modified Kirby Bauer disc diffusion method. MRSA was confirmed by using cefoxitin disc. Results: A total of 109 S. aureus (98 from dairy workers and 11 from butter samples) were isolated. Out of them 32 MRSA were isolated from dairy workers and 4 from butter samples. The association between age group and MRSA was found insignificant (p = 0.115). The association of MRSA between male and female workers was found significant (>0.05). About 86% of the MRSA isolates were susceptible to Gentamicin (86.11%) followed by Ciprofloxacin (77.78%). Conclusion: Detection of MRSA among dairy workers and dairy products warrants proper handling and adequate control measures to prevent transmission of MRSA from dairy industry.


2012 ◽  
Vol 36 (0A) ◽  
pp. 28-31
Author(s):  
نهاد عبدالحسين جعفر

The study was designed for isolation of Staphylococcus aureus from raw milk of cows at different regions of salah al-din province. A total number of 109 samples were collected form October (2010) to May (2011). The result of study showed that the number of isolates were (14) from (60) positive samples (82.22%). Antibiotic susceptibility test showed different results for susceptibility according to types of antibiotics that used in this study which include the followings: Amoxycillin, Ampicillin, Cefoxetine, Methcillin, Ciprofloxacin, Clavulinic acid and Erythromycin. The results showed that 50% of the isolates were susceptible for Methecillin, Cefoxetine, and Clavulanic acid-Amoxycillin), While Erythromycin was active against (79%) of the isolates, and Ampicillin was active against (57%), on the other hand, all isolates were susceptible to Ciprofloxacin which considered the most effective antibiotic against the bacteria in this study (100%).


2021 ◽  
Vol 3 (2) ◽  
pp. 60-64
Author(s):  
Ali Elshafei

Milk and milk-products represent the main basic nutritional healthy food in the human diet; however, milk is also a favorable source of microbial infection for human health when milk and milk products are consumed without applying hygiene milk practices methods such as pasteurization and other effective methods to avoid contamination risk. The presence of microorganisms in milk could result in spoilage and severe diseases to humans. Several recent preservation systems such as heating, refrigeration, and the addition of safe antimicrobial compounds can be used to reduce the risk of outbreaks of dairy product poisoning. Proper food control programs must be implemented in all countries around the world to ensure the safety of food and dairy products. Investigators reported the importance of applying effective hygiene practices during milking and handling of raw milk to reduce the risk of contamination on the farm and in the milk processing plant in the industry.


2020 ◽  
Vol 11 (2) ◽  
pp. 42-62
Author(s):  
Anas Almousawi ◽  
Abdullah Alhatami ◽  

Background: Staphylococcus aureus (S. aureus) causes a difficult problem in the poultry industry because it causes diseases that are difficult to treat due to the resistance of these bacteria to antibiotics and their possession of a battery of virulence and resistance genes in addition to their ability to produce thick biofilms. Method: A cross-sectional study conducted to collect a total of 53 samples from different clinical cases in broilers during the period from August 2019 to February 2020 in Al-Najaf and Karbala cities, The clinical isolates were determined by using the conventional standard biochemical tests. All the specimens cultured on blood agar medium supplemented with 5% blood for primary isolation and selected by using selective media mannitol salt agar (MSA) for confirmation the mannitol fermentation, then subjected to gram’s staining, catalase, oxidase, and further slide coagulase test, then all S. aureus isolates tested by antibiotic susceptibility test, and screened for the presence of mecA and mecC genes using PCR for the detection of MRSA isolates, then subjected to the detection of virulence genes (pvl and eta), antibiotic resistance gene (cfr), identification of integron class 1, biofilm formation assay, the multi-druge resistance profiles (MDR) and multible antibiotics resistance (MAR) indexes were calculated. Results: the isolation rate of S. aureus from the broilers' clinical samples was 37.7%. The antibiotic susceptibility test revealed that 85% of S. aureus isolates were resistant to one or more of the antibiotic tested. All 53 isolates were assessed for the presence of mecA and mecC genes by using PCR. The mecA gene-specific PCR product was seen in 7 (35%) isolates and considered as MRSA. Among all S. aureus isolates, two isolates were positive for the eta gene, and 15 (75%) isolates harboring integron class 1, while the biofilm formation test revealed that 7 (35%) was positive biofilm producers and three of them were strong producers, consequentlly, 13 (65%) of the isolates were resisted to three or more antibiotics and considered as MDR strains. While pvl, cfr, and mecC gene were not detected among S. aureus isolates. Conclusion: the current study revealed that S. aureus possess a real threat in the poultry industry reflecting a public health problem due to the large acquisition of antibiotic resistance genes by these bacteria, the results indicated a high percentage of isolates having MDR characteristic, and two of them were resistant to all antibiotics tested. In addition to the presence of two MRSA isolates carrying the eta gene, this indicating that they are of human origin.


2021 ◽  
Vol 11 (4) ◽  
pp. 642-657
Author(s):  
Shimaa Tawfeeq Omara ◽  
Ashraf Samir Hakim ◽  
Magdy Ali Bakry

Detailed information on the resistance patterns of Staphylococcus aureus (S. aureus) in milk and cheese is strongly required to facilitate risk assessment analysis in case of food poisoning context and to improve therapeutic approaches used in dairy farms. The present study aimed to perform phenotypic and genotypic antimicrobial characterizations of methicillin, vancomycin, and erythromycin-resistant S. aureus isolated from milk and dairy products through screening mecA, vanA, and ermC using molecular PCR amplification technology. Moreover, the association between each genotypic and its related antibiotic resistance phenotypic features within the isolated S. aureus strains were analyzed. Moreover, the current study aimed to study MRSA's ability to form biofilms. Out of 226 milk and dairy product samples collected from different retailers in Giza Governorate, 69.5% of the samples were positive for the presence of S. aureus. The isolation rate of S. aureus strains from cattle milk, sheep milk, white cheese, flamenco, and mesh samples were 79.7%, 76.5%, 56.0%, 40.0%, and 94.7%, respectively. Multidrug-resistant S. aureus (MDR) was detected in 51% of all isolated S. aureus strains. All tested S. aureus strains were sensitive to trimethoprim-sulfamethoxazole, linezolid, ciprofloxacin, and gentamycin. However, their resistance rates against penicillin, oxacillin, vancomycin, erythromycin, tetracycline, clindamycin and chloramphenicol were 62.4%, 65.0%, 44.6%, 45.9%, 21.0%, 14.0%, and 2.5%, respectively. Of the isolated S. aureus strains, 72.6%, 40.1%, and 48.4% were carriers for mecA, vanA, and ermC genes and the amplified products were at 310, 1030, and 295 bp, respectively. Methicillin-resistant S. aureus isolates were detected in 47.1% of all isolated S. aureus strains. The results indicated that 35.0% of the tested S. aureus strains were genotypic vanA gene carriers and phenotypic resistant to vancomycin representing vancomycin-resistant S. aureus strains. Moreover, 42.7% of all isolated S. aureus strains were carriers for ermC gene and were phenotypic resistant to erythromycin representing erythromycin-resistant S. aureus. The presence of mecA, vanA, and ermC genes in S. aureus was statistically associated with their related phenotypic resistance patterns against both penicillin and oxacillin, vancomycin, and erythromycin, respectively. Moreover, along with an increase in the frequency of mecA, vanA, and ermC genes, their phenotypic antibiotic resistance patterns sharply increased with an odd ratio >1. Of MRSA isolates, 6.8% indicated weak biofilm-formation ability, while 93.2% exhibit no biofilm-forming ability.


2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Fikirte Lemma ◽  
Haile Alemayehu ◽  
Andrew Stringer ◽  
Tadesse Eguale

Staphylococcus aureus is a contagious pathogen that can cause various diseases in both humans and animals. Antimicrobial-resistant S. aureus is becoming an extremely important global health problem. A cross-sectional study was conducted from December 2019 to May 2020 to assess the occurrence of S. aureus and its antimicrobial susceptibility profiles in milk and traditionally processed dairy products in selected subcities of Addis Ababa. A total of 255 dairy product samples (175 raw milk and 80 traditionally processed dairy products) were collected from farms and retail markets. Samples were cultured for S. aureus according to standard microbiology techniques, and the Kirby–Bauer disk diffusion method was used to assess antimicrobial susceptibility of isolates to a panel of 12 antimicrobials. Susceptibility to methicillin was determined based on the sensitivity of isolates to cefoxitin, and resistant isolates were investigated for the presence of mecA and mecC genes using PCR. Staphylococcus aureus was isolated from 43 (24.6%) of milk, 7 (17.5%) of yogurt, and 2 (5%) of cottage cheese. A significantly higher rate of contamination with S. aureus was recorded among milk samples compared to yogurt and cottage cheese ( p = 0.019 ). Out of 52 S. aureus isolates investigated for susceptibility to 12 antimicrobials, 49 (94.2%) of the isolates were resistant to ampicillin and 42 (80.8%) to amoxicillin+clavulanic acid. Twenty (38.5%) of the isolates were methicillin-resistant S. aureus (MRSA) based on susceptibility to cefoxitin. However, only one of these isolates (5%) was positive for mecA gene, and none of them were positive for the mecC gene. There was no significant difference ( p > 0.05 ) in the rate of occurrence of MRSA among isolates from different sources. In conclusion, this study demonstrated a significant level of contamination of milk and dairy products with S. aureus and most isolates were multidrug resistant. The occurrence of MRSA in raw milk and dairy products signifies a serious public health threat as the practice of consuming raw dairy products in the study area is widespread. The lack of agreement between phenotypic and genotypic detection of MRSA suggests the need for further study to identify the genetic basis for the observed resistance phenotype.


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


2015 ◽  
Vol 7 ◽  
pp. 169-177 ◽  
Author(s):  
Azar Asadollahi Dehkordi ◽  
Elahe Tajbakhsh ◽  
Forough Tajbakhsh ◽  
Faham Khamesipour ◽  
Manouchehr Momeni Shahraki ◽  
...  

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