Occurrence of E. coli isolates
In this investigation, on screening a total of 405 raw fresh meat samples collected from several butcher shops in the Udgir city, Maharashtra altogether 39 samples were found positive for
E. coli suggesting the overall occurrence of
E. coli to the tune of 9.63%. Chicken and chevon samples exhibited 12% (24/200) and 7.32% (15/205) occurrences of target organism, respectively.
In vitro pathogenicity assessment
All 39 presumed
E. coli isolates tested positive in the Congo red dye binding experiment and haemolysis assay used to assess the pathogenicity of bacteria. The positive isolates developed intense brick red colonies on Congo red agar and showed haemolysis in haemolysis assay.
Antibiogram profiling of recovered E. coli isolates
The results showed that the majority of the isolates had multidrug resistance characteristics (Table 3). Two individual isolates recovered from raw chicken meat sample demonstrated resistance against 12 and 11 antibiotics respectively. while, two other isolates recovered from chicken samples and 3 isolates recovered from chevon samples showed resistance against 10 antibiotics (Table 3). Similar trends were also seen in the current study’s observation of sample group-wise antibiotic resistance of
E. coli isolates. As shown in Table 2, a significant percentage of
E. coli isolates obtained from chicken and chevon exhibited antibiotic resistance to several drugs. The majority of these isolates were found to be resistant to antibiotic classes based on the data obtained are β-lactams (94.87%), lincosamides (84.62%), 4
th Generation cephalosporins (82.05% each), DHFR Inhibitors (64.10%), glycopeptides (51.28%) followed by fluoroquinolones, quinolones, 2
nd and 3
rd generation cephalosporins (48.72% each) (Table 1).
Multiple drug resistance (MAR) index
The multi-drug resistant (MDR) isolates in the present study showed resistance to a minimum of 4 and a maximum of 12 antibiotics. Thus, 9 resistance patterns were observed ranging from 4 to 12 antibiotics with maximum multiple antibiotic resistance (MAR) index of 0.8 and a minimum MAR index of 0.27 in MDR isolates as depicted in Table 3. A MAR greater than 0.2 indicates that places with high usage of antibiotics are the source of contamination (
Davis and Brown, 2016).
Escherichia coli organism is also regarded as an indicator of faecal contamination in food and water. It is a commonly found commensal bacterium in humans and the environment
(Rahman et al., 2017). In this study, the overall occurrence of
E. coli was observed to the tune of 9.63% in raw fresh meat samples collected from different butcher shops in the Udgir city, Maharashtra. These findings can be corroborated with
Suryawanshi et al., (2023) and
Deshmukh et al., (2023) who made similar observations, reporting an overall prevalence of
E. coli of 9.17% and 12%, respectively, in raw fresh meats collected from same geographic area.
In current investigation, chicken and chevon samples revealed 12% (24/200) and 7.32% (15/205) occurrence of target organism.
Suryawanshi et al., (2023) screened 425 samples of fresh meats comprising chicken, mutton, chevon and carabeef. Researchers found that the occurrence of
E. coli was 12.50% (15/120) in chicken and 9.52% (10/105) in chevon, which is consistent with the results of the present study. However, these results contradict with the findings reported by
Bhoomika et al., (2016) and
Mawia et al., (2012). Bhoomika et al., (2016) reported 66.32% (65/98) and 46.34% (38/82) occurrence of
E. coli in chicken meat and chevon samples collected in Chhattisgarh, India. While,
Mawia et al., (2012) also obtained 47 (28.14%)
E. coli isolates comprising 22 (25.88%) from chevon samples and 25 (30.49%) from chicken on screening 167 meat samples collected from local markets of Jammu, India. These values of higher prevalence of
E. coli from chicken and chevon samples reported can be attributed to the variation of sampling methods, detection protocols, poor sanitary practices adopted during handling of meat with the use of microbiologically contaminated water and difference of area of sample collection.
Berkhoff and Vinal (1986) and
Roy et al., (2006) confirmed the recovery of 100% Congo red dye-binding isolates in their investigations. Based on their findings, researchers suggested using the Congo red binding assay as a phenotypic marker to discriminate between pathogenic and non-pathogenic isolates. In current investigation, all 39
E. coli isolates were tested positive in the Congo red dye binding experiment and also showed haemolysis in haemolysis assay, suggesting their invasive character.
Microbiologists and public health veterinarians are urged all over the world to survey the antibiotic resistances of key foodborne pathogens in order to deliver epidemiological data to the professionals in charge of public health in order to make recommendations on the appropriate use of antibiotics. For current experiment, the most frequently used antibiotics in both human and animal health were chosen to be tested against recovered
E. coli isolates. The investigation’s findings showed that the majority of the isolates had a pattern of multidrug resistance. All 39 isolates recovered were found to be resistant to at least four of the antibiotics that were tested against them. Occurrence of two isolates from chicken showing resistance against 12 and 11 antibiotics respectively was also noted. While, 06 isolates including 03 from chicken and remaining 03 from chevon, displayed resistance against 10 different antibiotics. In our investigation, a very high percentage of antibiotic resistance was noted against amoxycillin-clavulanic acid (94.87%), lincomycin (84.62%), cefepime (82.05%), trimethoprim (64.10%), vancomycin (51.28%), ofloxacin, nalidixic acid, cefotaxime, cefaclor and tetracycline (48.72% each) followed by other antibiotics with resistance levels under 40%. Similar high multidrug resistance pattern was also reported by other researchers like
Deshmukh et al., (2023), Adzitey (2015) and
Uzeh et al., (2021). The results of present study are consistent with that of observed by
Deshmukh et al., (2023) who screened
E. coli isolates recovered from poultry farms environment, chicken meat retailers shop, raw chickens from Udgir city of Maharashtra, wherein they reported high percentage of antibiotic resistance against lincomycin and tetracycline (85.29%), nalidixic acid and vancomycin (82.35% each), ofloxacin (67.64%), amoxycillin-clavulanic acid (61.76%), cefepime (41.17%), trimethoprim (38.23%) and cefaclor (47.05%) with similar MDR pattern of each isolate showing resistance to at least four antibiotics. Adzitey (2015) screened 45
E. coli isolates from Beef and its related samples of Ghana and observed a very high resistance to amoxycillin-clavulanic acid (86.67%), trimethoprim (82.22%) and vancomycin (88.89%). Similarly,
Uzeh et al., (2021) studied
E. coli isolates from raw meats and revealed MDR in 22% of the isolates, as well as resistance against ampicillin (57%), tetracycline (45%) and sulfamethoxazole-trimethoprim (21%).
Despite the lack of antibiotic usage histories to link with susceptibility data, findings of this study might be interpreted as reflecting, at least in part, the selective pressures exerted by antimicrobial use in food animal production and processing contexts. It is hypothesised that increasing levels of resistance in food animals are attributable in part to modern production practises, in which antibiotics for disease prevention and control are provided through water as well as feed. Resistance to expanded-spectrum cephalosporins, as observed in current experiment, is of particular concern because these antimicrobials are used as first-line therapy for a variety of Gram-negative infections, especially systemic and paediatric salmonellosis.
In this study, it was noted that a noteworthy percentage of
E. coli isolates recovered from chicken as well as chevon samples exhibiting virtually identical trend of MDR pattern to set of antibiotics It may be the result of a meat-selling strategy used by retailers in India, in which the same shops sell both chicken and chevon meat, based on the preferences of the customers., It additionally introduces the chance that
E. coli bacteria may appear as a secondary contamination while cutting chicken and chevon meats with the same contaminated cutting boards or knives and/or washing water. Insufficiently cleaned chopping boards and post-processing meat handling equipment have been linked to cross-contamination, according to
Suryawanshi et al., (2023). Uzeh et al., (2021) also speculated the possibility of contamination of raw meats with antibiotic resistant pathogenic organisms at unhygienic slaughter as well as sale points.
Finding regarding MDR isolates in the present study showing resistance to a minimum of 4 and a maximum of 12 antibiotics with minimum MAR index of 0.27 and maximum MAR index of 0.8 and 9 resistance patterns are comparable with
Adzitey (2015), who observed MAR index ranging from 0.11to 0.78 shown by
E. coli isolates recovered from meats. Multidrug resistant
E. coli was also discovered by
Hassanien et al., (2016), Adzitey et al., (2020), Abass et al., (2020), Jaja et al., (2020), Mir et al., (2022) Ahmed et al., (2023), with MAR indices ranging from 0.14-1, 0.13-1, 0.22-0.78, 0.2–0.5, 0.45-0.81 and 0.32-0.95, respectively.