Foodborne pathogens are not only the key source of foodborne disease and also the main issue of global food safety. They are emerging and becoming a significant public health problem worldwide. It is the etiological agent responsible for animal and human listeriosis
In addition, a further concern is due to the augmented detection of antimicrobial-resistant
Currently, in India, lack of information about the antimicrobial susceptibility and predominance of
In our study, a total of 105 different samples from RTE foods were randomly collected from departmental stores and street vendors in and around Kanchipuram, Tamil Nadu. All the RTE samples were carried in polythene bags and kept at (4°C) on an icebox and shifted to the laboratory and the bacteriological analysis was made within 2 hours.
1g of each sample was transferred aseptically to 9 ml of half Fraser broth (HFB) (Himedia, India) for primary enrichment and incubated for 24h at 37°C. After that, 0.1ml of culture from HFB was again inoculated into 10ml of Fraser broth (FB) and allowed to incubate for 24 to 48hrs at 37°C. The culture was then streaked over Polymyxin Acriflavin Lithium chloride Ceftazidime Aesculin Mannitol (PALCAM) agar in a loop (Himedia, India) and incubated at 37°C for 24 to 48hrs. After incubation, about 3 to 5 selected
All the suspected colonies of
The antimicrobial-resistance pattern of all
DNA was isolated by QIAamp DNA mini kit from Qiagen Germany. In PCR analysis, the Taq PCR Master Mix Kit from Qiagen, Germany was used. A 50 µL reaction mixture was prepared which includes 25 µL PCR Master Mix, 1 µL of each primer, 2 µL of DNA, and finally, the reaction mixture was adjusted to 50 µL using distilled water. The approached thermal profile was applied during PCR. The sequence for Forward primer was 5’- GTGCCAGCAGCCGCGGTAA -3’, and the sequence for reverse primer was 5’- AGGGTTGCGCTCGTTG -3′. PCR cycle: preliminary denaturation at about 95°C for 3 min; every 35 cycles consist of denaturation at 94°C for the 30s, annealing at 53°C for 15s, extension at 72°C for 90 s, and at 72 °C for 7 min for a final extension. Agarose gel (0.7 %) electrophoresis was used to analyse PCR products (15 µL) and envisioned in a gel documentation system under UV light
The 16S rRNA gene was sequenced from
RTE foods are mostly associated with the outbreak of various diseases and rare cases of listeriosis. In particular,
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1 |
Banana Milkshake |
15 |
2(13.3%) |
13(86.6%) |
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2 |
Chocolate Milkshake |
10 |
1(10.0%) |
9(90.0%) |
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3 |
Rose milk |
15 |
0 |
15(100%) |
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4 |
Vanilla Milkshake |
15 |
0 |
15(100%) |
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5 |
Strawberry Milkshake |
10 |
1(10.0%) |
9(90.0%) |
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6 |
Almond milk |
20 |
5(25.0%) |
15(75.0%) |
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7 |
Curd |
10 |
3(30.0%) |
7(70.0%) |
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8 |
Cheese |
10 |
3(30.0%) |
7(70.0%) |
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Total |
105 |
15(14.3%) |
90(85.7%) |
No = Serial number; 0 = Not Detected
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1 |
SELM01 |
Banana milkshake - I |
ENR |
2 |
SELM02 |
Banana milkshake - I |
ENR |
3 |
SELM03 |
Banana milkshake - II |
WBD |
4 |
SELM04 |
Banana milkshake - II |
WBD |
5 |
SELM05 |
Chocolate milkshake - I |
ENR |
6 |
SELM06 |
Strawberry milkshake - II |
ENR |
7 |
SELM07 |
Almond milk – I |
ENR |
8 |
SELM08 |
Almond milk – I |
ENR |
9 |
SELM09 |
Almond milk – I |
WBD |
10 |
SELM10 |
Almond milk – I |
WBD |
11 |
SELM11 |
Almond milk – III |
KPM |
12 |
SELM12 |
Almond milk – II |
ENR |
13 |
SELM13 |
Almond milk – II |
ENR |
14 |
SELM14 |
Almond milk – III |
WBD |
15 |
SELM15 |
Curd – II |
ENR |
16 |
SELM16 |
Curd - II |
ENR |
17 |
SELM17 |
Curd - I |
KPM |
18 |
SELM18 |
Curd -I |
WBD |
19 |
SELM19 |
Curd - I |
WBD |
20 |
SELM20 |
Cheese - I |
WBD |
21 |
SELM21 |
Cheese - I |
WBD |
22 |
SELM22 |
Cheese - III |
WBD |
23 |
SELM23 |
Cheese - III |
WBD |
24 |
SELM24 |
Cheese - II |
KPM |
25 |
SELM25 |
Cheese - II |
KPM |
WBD - Walajabad, KPM -Kanchipuram, ENR– Enathur
In our study, ten varieties of curd samples were considered for studying the prevalence rate of
In the current study,
The antimicrobial susceptibility of 25 isolates against 12 antibiotics was examined using the Kirby-Bauer method. A susceptibility test was assigned through the disk diffusion method using CLSI guidelines value and the results are summarized in
Of the total isolates, 40% exhibited resistance to clindamycin. 44% of the isolate showed resistance to Lincomycin and 80% of isolates exhibited sensitivity to the Vancomycin antibiotic. The susceptibility pattern of
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1 |
P |
6 |
24 |
2 |
AMX |
6 |
24 |
3 |
CB |
9 |
36 |
4 |
MET |
13 |
52 |
5 |
AZM |
7 |
28 |
6 |
CD |
10 |
40 |
7 |
L |
11 |
44 |
8 |
VA |
5 |
20 |
9 |
RF |
13 |
52 |
10 |
RO |
9 |
36 |
11 |
TEI |
14 |
56 |
12 |
LZ |
6 |
24 |
Subsequently, 52% of isolates exhibited resistance to Rifampicin, and 36% of isolates showed resistance to Roxithromycin antibiotics. 56% of isolates found resistance to Teicoplanin antibiotics and 24% resistant against linezolid. In detail 6 isolates exhibited resistance to 1 antibiotic, 7 isolates showed resistance to 2 antibiotics and 1 isolate showed resistance to many antibiotics
Genetic comparison of
From this sequencing result, it has been evidenced that the species isolated from RTE food was the
The phylogenetic tree grouped clustered was compared with our
In India, no clear documentation regarding the epidemics of human listeriosis was studied, the current study showed about a 14.3% prevalence of
The author Sankaradoss Elavarasi acknowledges Prof. K. R. Venkatesan, Principal, Sri Sankara Arts and Science College (Autonomous), and the management of SSASC for providing lab facilities to carry out the experiments and Dr. P. Saravanan, Assistant Professor, Department of Biotechnology, Sri Sankara Arts and Science College 208 (Autonomous) for his support in manuscript preparation.