scholarly journals Staphylococcus aureus Bacteria Resistant to Methicillin in Raw Milk

Author(s):  
Farnush Kazemi ◽  
Shila Safaeian ◽  
Roxana Moogouei

The presence of antibiotic-resistant strains of Staphylococcus aureus (particularly methicillin-resistant strains) in food of animal origin is considered as a severe threat to human health due to numerous clinical complications. This study tended to determine the prevalence of methicillin-resistant S. aureus in samples of raw milk distributed in Tehran using antibiotic susceptibility testing methods. In the present study, 100 raw milk samples were taken from the centres of production and purchase of milk and its products in Tehran; the samples were evaluated by culture in terms of infection with coagulase-positive S. aureus. Finally, antibiotic resistance pattern of isolates was studied using disk diffusion agar. The average colony count was estimated. Raw milk cultures were estimated at 2×105-4×105 cfu/ml. Based on the results of culture, 36 samples of raw milk tested were icnfected with positive-coagulase S. aureus. The highest susceptibility was observed for ciprofloxacin and gentamicin (100%) and the highest resistance was observed to penicillin, tobramycin, oxacillin and ceftazidime. The results showed the prevalence of infection of raw milk with S. aureus. Moreover, prevalence of S. aureus resistant to a wide range of antibiotics, more importantly, methicillin resistant, was significant in the tested samples. Therefore, adherence to and control of sanitation in different stages of production, supply and consumption of milk can prevent human infection.

2010 ◽  
Vol 73 (7) ◽  
pp. 1325-1327 ◽  
Author(s):  
JAROSŁAW BYSTROŃ ◽  
MAGDALENA PODKOWIK ◽  
KAMILA KORZEKWA ◽  
ELŻBIETA LIS ◽  
JERZY MOLENDA ◽  
...  

In this study, the molecular characteristics of food-derived oxacillin-resistant Staphylococcus aureus were determined. Eight borderline oxacillin-resistant strains with MICs of 2 to 4 μg/ml were identified from 132 S. aureus isolates of food origin. One of the two isolates with a MIC of 4 μg/ml was methicillin-resistant determinant (mecA) gene positive, and the other six with MICs of 2 μg/ml were mecA negative. The mecA-positive isolate was classified as sequence type (ST)228, staphylococcal protein A (spa) type t041, and carried the staphylococcal cassette chromosome mec type I element. Two borderline oxacillin-resistant strains were classified as spa t008 and ST8, and the remaining five as spa t164 and ST20. The mecA-positive strain and four borderline oxacillin-resistant strains were found enterotoxigenic. The enterotoxin genes detected in these strains included selp, egc1, and sed-sej-selr. The borderline-resistant S. aureus isolates from a manually handled product, i.e., minced pork, were shown genetically related to strains associated with human infections. This suggests that humans can be considered as a source of contamination of this food with oxacillin-resistant S. aureus strains. The genotypes of the investigated milk borderline-resistant isolates were shown to occur not only in cows, but also in humans. Since manual handling is reduced in raw milk production, a human origin of S. aureus seems unlikely. Because knowledge of the genotypes of animal staphylococci is limited, more research is needed to address the question of the origin of antibiotic-resistant S. aureus strains in food.


2015 ◽  
Vol 78 (10) ◽  
pp. 1879-1884 ◽  
Author(s):  
KHALID IBRAHIM SALLAM ◽  
SAMIR MOHAMMED ABD-ELGHANY ◽  
MOHAMED ELHADIDY ◽  
TOMOHIRO TAMURA

The emergence of livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) in food-producing animals is of increasing interest, raising questions about the presence of MRSA in food of animal origin and potential sources of transmission to humans via the food chain. In this study, the prevalence, molecular characterization, virulence factors, and antimicrobial susceptibility patterns of MRSA isolates from 200 retail raw chicken samples in Egypt were determined. MRSA was detected by positive amplification of the mecA gene in 38% (76 of 200) of chicken samples analyzed. This represents a potential public health threat in Egypt, as this contamination rate seems to be the highest among other studies reported worldwide. Furthermore, genes encoding α-hemolysin (hla) and staphylococcal enterotoxins (sea, seb, and sec) were detected in all of the 288 MRSA isolates. Nonetheless, none of the strains tested carried tst, the gene encoding toxic shock syndrome toxin 1. Antimicrobial resistance of MRSA isolates was most frequently detected against penicillin (93.4%), ampicillin (88.9%), and cloxacillin (83.3%). These results suggest that retail chicken might be a significant potential source for transmission of multidrug-resistant and toxigenic S. aureus in Egypt. This underlines the need for stricter hygienic measures in chicken production in Egypt to minimize the risk of transmission of these strains to consumers. To the best of our knowledge, this is the first study that reports the isolation and molecular characterization of MRSA in retail chicken samples in Egypt.


2016 ◽  
Vol 2 (3) ◽  
pp. 396-401
Author(s):  
Mukta Talukder ◽  
HM Manir Ahmed

The extensive progress of dairy sectors in a developing country like Bangladesh, led to widespread use of antibiotics to improve the health and productivity of animals. Prolonged usage may lead to antibiotic residues in foods of animal origin; hence, the emergence of antimicrobial resistant microorganisms. Accurate data on the antibiotic usage in livestock treatment, antibiotic residues and antimicrobial resistances in raw milk in Bangladesh are lacking. This study aimed to investigate the types and usages of antibiotics in cattle, their potential microbial resistances in raw milk samples. To do so, a total of 54 raw milk samples were evaluated and the bacterial isolates were identified and measured for resistance to 4 antibiotics most commonly used during bacterial infection Bangladesh. Amongst all 54 (100%) isolates were positive to S. aureus and 36 (66.67%) isolates were positive to E coli. Determination of the antibiotic resistance pattern of isolates showed that all isolates of S. aureus were resistant to cefoxitin (81.48%), ampicillin (64.81%), ciprofloxacin (51.85%), and gentamycin (70.37%). E. coli showed resistance to cefoxitin (69.44%), ampicillin (83.33%), ciprofloxacin (77.78%), and gentamycin (86.11%). However multidrug resistance pattern was also found. The obtained results provide evidence that antimicrobial resistant strains of the above pathogens have become remarkably widespread in raw milk. This requires better management for antibiotic usages among livestock farmers to control sources of food contamination and reduce the health risks associated with the development of resistant microbial strainsAsian J. Med. Biol. Res. September 2016, 2(3): 396-401


2007 ◽  
Vol 12 (45) ◽  
Author(s):  
L Heggelund ◽  
H Holm Samdal ◽  
R Eggum ◽  
T Jacobsen ◽  
T Bruun ◽  
...  

Staphylococcus aureus, including methicillin-resistant strains (MRSA), may cause a wide range of infections involving skin and soft tissue, as well as bone, airways, and endovascular grafts.


2016 ◽  
Vol 79 (11) ◽  
pp. 1990-1994 ◽  
Author(s):  
BELGİN SİIRİKEN ◽  
TUBA YILDIRIM ◽  
AKİF KORAY GÜNEY ◽  
İRFAN EROL ◽  
BELMA DURUPINAR

ABSTRACT In the present study, 175 coagulase-positive Staphylococcus (CPS) isolates recovered from samples of beef (n = 110), raw milk n = 56), and fish (n = 9) were analyzed for methicillin resistance using MIC and PCR assays. Methicillin-resistant (MR) Staphylococcus aureus (SA) isolates were then characterized using pulsed-field gel electrophoresis (PFGE). According to findings, 62 (35.4%) of the isolates (44 from beef, 9 from milk, and 9 from fish) were identified as S. aureus based on the presence of the nuc gene. MRCPS was detected in 18 (10.3%) of 175 CPS isolates based on the presence of the mecA gene. Among these isolates, 15 (24.2%) were MRSA: 4 (26.7%) from beef, 2 (13.3%) from milk, and 9 (60%) from fish. However, based on the MIC assay, 21 (12.0%) of the CPS isolates (1 from beef, 15 from milk, and 5 from fish) were MRCPS, indicating a discrepancy between the results of these two methods. The PFGE results indicated genetic heterogeneity of the isolates; six PFGE clusters were found. These results confirm that MRSA is present in foods of animal origin, which is a concern to human health, and indicate the importance of method selection for determination of methicillin resistance. The identity of MR isolates should be verified by PCR to obtain more reliable results.


2020 ◽  
Vol 367 (23) ◽  
Author(s):  
Asima Zehra ◽  
Maliha Gulzar ◽  
Randhir Singh ◽  
Simranpreet Kaur ◽  
J P S Gill

ABSTRACT The aim of this study was to illustrate the relative pervasiveness of Borderline Oxacillin Resistant Staphylococcus aureus (BORSA) and Methicillin-Resistant Staphylococcus aureus (MRSA) in community and food of animal origin and their relationship with other genetic determinants. Staphylococcus aureus isolates were subjected to E-test using the antibiotics: oxacillin, ceftriaxone, cotrimoxazole, vancomycin, genotypic tests for the genes mecA, vanA, blaZ, pvl gene and SCCmec typing. The prevalence of S. aureus (MRSA) in the food of animal origin and community settings was 21% (1.8% MRSA) and 21.9% (7.4% MRSA), respectively. SCCmec type V was prevalent among the food of animal origin, while SCCmec type IVa among the community isolates. The likelihood of MRSA presence among community isolates was three times more than in isolates from chicken and milk samples. Likewise, the likelihood of detecting pvl positive MRSA (pvl+MRSA) isolates was 4-fold higher in the community setting than in the food of animal origin. The mecA negative BORSA (mecA−BORSA) was a frequently observed phenotype among S. aureus isolates. Also, co-detection of pvl and cotrimoxazol resistance was reported in this study although there was no noteworthy correlation of cotrimoxazol resistance with the type of sample. Isolates from milk and community settings exhibit higher minimum inhibitory concentration to vancomycin (Vancomycin MIC creep, 2–4 µg/mL). Significance Current study provides the information on the statistical relationship between the genetic determinants of S. aureus with respect to sample type, and additionally the correlation that exists between the pvl and MRSA, pvl and cotrimoxazol resistance, vancomycin MIC and MRSA/Methicillin-Susceptible S. aureus (MSSA).


2021 ◽  
Vol 22 (5) ◽  
pp. 2752
Author(s):  
Shu Wang ◽  
Ok-Hwa Kang ◽  
Dong-Yeul Kwon

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen worldwide and has acquired multiple resistance to a wide range of antibiotics. Hence, there is a pressing need to explore novel strategies to overcome the increase in antimicrobial resistance. The present study aims to investigate the efficacy and mechanism of plant-derived antimicrobials, trans-cinnamaldehyde (TCA) in decreasing MRSA’s resistance to eight conventional antibiotics. A checkerboard dilution test and time–kill curve assay are used to determine the synergistic effects of TCA combined with the antibiotics. The results indicated that TCA increased the antibacterial activity of the antibiotics by 2-16-fold. To study the mechanism of the synergism, we analyzed the mecA transcription gene and the penicillin-binding protein 2a level of MRSA treated with TCA by quantitative RT-PCR or Western blot assay. The gene transcription and the protein level were significantly inhibited. Additionally, it was verified that TCA can significantly inhibit the biofilm, which is highly resistant to antibiotics. The expression of the biofilm regulatory gene hld of MRSA after TCA treatment was also significantly downregulated. These findings suggest that TCA maybe is an exceptionally potent modulator of antibiotics.


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