الفهرس 
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Abstract
The lack of fully understanding of how ESBL PE was raised at the interfaces of livestock, wildlife, and the environment, inhibits our ability to develop mitigation strategies. There is limited information available to determine the critical natural carrier/reservoir of ESBL PE Effective mitigation strategies such as farm management, biosecurity, and hygiene might facilitate the reduction of ESBL PE in livestock also new strategies are needed to combine knowledge of the environmental, animal, and bacterial aspects to tackle this global issue. To achieve the aims of the current study, the research plan was divided into two sections; a cross sectional study and a retrospective study.
Cross sectional study was carried out in Alexandria, Behera and Kafr El-sheikh Provinces for a period of 5 months from January to May 2020. The study population consisted of dairy cattle farms and poultry farms beside farm workers (human at risk for assessment of zoonotic potential of extended spectrum beta lactamase producing Enterobacteriaceae). A total of 111 different samples were collected including rectal swabs from dairy cattle and calves beside milk, water, ration and milking machine swabs. In addition, 177 cloacal swabs were collected from poultry farms beside litter, ration and water samples. Finally, a total of 25 hand swabs were collected from workers in cattle and poultry farm.
A retrospective study was conducted on confirmed patients with ESBL PE infection during the period extended from January, 2019 to August, 2020. Data was kindly obtained from two hospitals; the first was located in Kafr El- Zayat district, Gharbya Province, while the other was located in Alexandria Province. In addition, data was obtained from a private laboratory in Damanhur, Beheira Province. Archival records of 320 patients with ESBL PE results were available for reviewing at the time of this study. Demographic data obtained included age, gender, type of examined samples and results of antibiotic sensitivity.
6.1. Cross section study on ESBL PE in cattle and poultry farms as well as human in contact:
It was recorded that the overall of estimated prevalence of ESBL PE in the examined samples was 85.6. The prevalence of ESBL PE in cattle farms, poultry farms and human was 70.2, 96.3 and 68%, respectively. It was noticed that the total prevalence of ESBL PE in cattle farm was 70.2% and the prevalence in cows’ rectal swabs, calves rectal swabs, milk, milking machine swabs and ration was 70.9, 61.2, 71, 100 and 100%, respectively.
The prevalence of ESBL PE in cow rectal swabs was 70.9 %; E.coli (45.4%), Klebsiella (31.8%) and mixed infections (Sample was positive for both E.coli and Klebsiella) (22.7 %).
This higher prevalence of ESBL PE in cattle farms in the current study clarified the potential zoonotic risk for farm workers beside the risk of dissemination of bacteria through human community outside farms.
The prevalence of ESBL PE in calves’ rectal swabs was 61.2%; E.coli was 52.6% followed by Klebsiella (36.8%) and 10.5% of samples showed mixed infections. This finding reflected a contamination from the environment, companion animals, workers, feeding equipment and ration.
The prevalence of ESBL PE in apparently healthy calves (62.5%) was higher than in diseased calves (57.1%). ESBL PE isolated from apparently healthy calves was E.coli (60%), followed by Klebsiella (33.3%) then mixed infection (6.6%), while ESBL PE isolated from diseased calves was Klebsiella (50%) followed by E.coli and mixed infection (25% for each).
The prevalence of ESBL PE in calves in relation to sex showed higher prevalence in males than females (70.5% and 50%, respectively). Also, it was recorded that the prevalence of ESBL PE E.coli was higher in males (66.6%) while ESBL PE Klebsiella was higher in females (42.8%).
The prevalence of ESBL PE in apparently healthy cows was 84.6% and the prevalence of E.coli, Klebsiella and mixed infection was 45.4%, 31.8% and 22.7%, respectively.
The prevalence of ESBL PE in samples of normal milk (73%) was higher than in samples of mastitic (66.6%). In addition, the prevalence of E.coli, Klebsiella and mixed infection in normal milk samples was 26.3%, 21.03% and 52.6%, respectively. While, in mastitic milk, the prevalence of E.coli and Klebsiella was 87.5% and 12.5%, respectively.
Concerning the antibiotic susceptibility testing for E.coli ESBL PE isolates obtained from cattle farms revealed that 94.4% were resistant to AMC, followed by 58.3% to CAZ and 41.6% to CL, 33.3% for LE, 25% to CTX, 23% to CPM then 9% to IPM, while for Klebsiella isolates, they were totally resistant to AMC and CPM followed by 78.9% to CAZ, 68.4% to CTX, 63.15% to CL, 47.36% to LE then 50% to IPM.
Most of isolates recovered from dairy cattle was phenotypically related to ESBL molecular type class C which mean that it show high resistance to extended spectrum cephalosporin with no inhibition mentioned to penicillin and clavulanic acid (beta lactamase inhibitor) and this resistance was higher in Klebsiella than E.coli. And this resistance may be attributed to several enzymes as AmpC enzymes (ACT-1, CMY-2, FOX-1, MIR-1, GCI and CMY-37) and ESBL enzymes as TEM-50.
The prevalence of ESBL PE in poultry farms was 96.8 %. In addition, the prevalence in cloacal swabs was 97.1 % including; E.coli (66.8%), Klebsiella (22.6%) and mixed infection (10.4%) while in ration samples was 100% including; E.coli (40%), Klebsiella (40%) and mixed infection (20%). Also in water samples, it was 100% including; E.coli (20%) and Klebsiella (80%) and finally in litter samples, it was 75%.
Concerning the antimicrobial sensitivity testing of E.coli isolates, it was detected that 98% were resistant to AMC, 97% to LE, 95.2% to CL, 88.6% to CTX, 77.3% to CAZ and 26.6% to IPM while for Klebsiella isolates, it was found that all isolates were totally resistant to AMC, CL and CPM, 93% were resistant to both CAZ and CTX, 89.6% to LE and finally high resistant to imipenem 72.7% was noticed.
The prevalence of ESBL PE farm workers was 68% including; Klebsiella (47.1%), E.coli (29.4%) and mixed infection (23.5%). Also, it was noticed that the prevalence of ESBL Klebsiella in human was higher than E.coli.
The prevalence of ESBL PE in farm workers in relation to gender clarified that the prevalence in males was 65.2% including; Klebsiella (46.6%), E.coli (26.6%) and mixed infection (26.6%). Only two females were included in the study and both was ESBL PE positive; one for Klebsiella and the other for E.coli.
The age wise positivity of ESBL PE in the examined farm workers cleared that the age group (45 - <55 years) scored the highest ESBL PE prevalence (100%) followed by the age group (35 - <45 years) and the age group (> 55 years) then age group (25 - <35 years) and finally, the age group (15 - <25 years).
It was observed that farm workers that were in contact with equine, cattle and poultry scored the highest prevalence (100%) followed by those who had contact with bovine and poultry (60%) then those who had contact with pets and poultry (50%) and finally, those who had contact with bovine (44.4%).
The results of phenotypic testing compared to PCR detection of ESBL/AmpC and Mcr-1 genes clarified that only 57.8% of represented isolates of E.coli were positive for Ctx-M, 89.4% were positive for SHV and 79% were positive for TEM while, only 10.5% were positive for AmpC and 68.4% for Mcr-1. On the other hand, for Klebsiella represented isolates, only 85% were positive for Ctx-M and all 14 samples were positive for SHV and TEM while, only 21.4% were positive for AmpC and 78.5% were positive for Mcr-1. Sequence analysis based on CTX-M gene revealed that all samples were genetically related to CTX-M 15 while only one sample represented E.coli isolated from human was related to CTX-M 14.
6.2. Retrospective study on ESBL PE in hospitalized patients based on hospital records:
The prevalence of ESBL PE in females (54.1%) was higher than in males (45.9%). The highest prevalence of ESBL PE was recorded in the age group > 65 years (49.1%) followed by the age group 45 > 65 years ( 25%) then age group 26 - < 45 years (13.8%) and the age group 13 - < 25 years (7.7%). Finally, the lower prevalence was recorded in age group 1 - < 13 years (4.4%).
Concerning E.coli isolates, the highest frequency was observed in urine samples (78.5%) then wound swab (10.4%), blood (5.2%), sputum (4.6%) followed by laryngeal (0.6%) and vaginal swabs (0.6%). Regarding K. pneumoniae isolates, the highest frequency was observed in urine (58.3%) followed by sputum (25.4%), wound swab (9.9%), blood (4.9%) while lower frequency was recorded in laryngeal and vaginal swabs (0.6% for each).