Molecular detection of antibiotic resistance genes in identified of Coagulase Negative Staphylococci from chickens flocks and hatcheries in Egypt.

Document Type : Original Article

Authors

1 Faculty of Veterinary medicine, Cairo University

2 Professor and head of Bacteriology , Mycology and Immunology Department, Faculty of Veterinary Medicine, Bani-suif University

3 Poultry and Rabbit disease Department/Faculty of veterinary medecine / Cairo University

4 Professor of Poultry Diseases Faculty of Veterinary Medicine, Cairo University

Abstract

The collected 942 samples (6 organ/bird) from 157 birds  taken from  34  broiler chicken farms aged 2- 31 days including 13 and 21 clinical diseased and apparently health flock as well as 221 hatchery samples. Samples were tested for isolation of Coagulase negative staphylococcus (CoNS).
 Results of isolation from chicken flocks with clinical signs are 9/13(69.23%) were positive.  Positive samples (11/354, 3.11%) including : 3liver, 4 kidney, 2 intestine, 1 air sac and 1  nasal sinus.   Out of apparent healthy flocks 8/21 (38.95%) were positive.  Positive samples (15/ 588, 2.55%)  including 3 liver, 2 kidney, 4 intestine, 3 lung, 2 air sac and  1 nasal sinus. Results showed that  15 positive flocks out of 34 flocks (34.09%) with 26 Staphylococcus isolates  from 942 samples (2.77%) including 6 liver, 6 kidney, 6 intestine, 4 lung, 2 air-sacs and 2 nasal sinus with rate of 3.82%,  3.82%, 3.82%, 2.55%, 1.27% and 1.27%; respectively.  Also12  isolates out of 26 (46.15%) were CoNS include  8 S. xylosus (75 %), 2 S. scuiri (16.67%)  and 2 S. lentus (16.67%).
 Hatchery samples reveals the isolation of 26 staphylococcus isolates (11.76%). The tested  108 fertile eggs and dead in shell embryos resulted in  14  and 12 isolates in rate of 12.96% and 13.79%; respectively. Ten isolates were CoNS (38.46%) and represented 4.52% out of total samples including  8 S. xylosus and 2 S. scuiri. Eight S. xylosus was 6 (5.55%) from infertile eggs and 2 (2.29 %) from dead in shell, While the  2 S. scuiri (1.85%) were obtained from infertile eggs. 
 The tested CoNS isolates showed 100% resistance to Oxytetracycline 30 µg/ml (T30), Trimethoprime   + Sulphamethexole 2.25/23.75 µg/ml (SXT) , Calindamycin 2 µg/ml (DA) and  Oxacillin 30 µg/ml (OX).  All isolates  were 100% susceptible to Vancomycin  30 µg/ml (VA) and 90%  susceptibility to   Enrofloxacin 5 µg/ml (ENR). Multidrug resistance was detected in form of resistance  to 9, 4 and 5 out of tested 13 antibiotics in 2 S.lentus , 5 S. scuiri and 15  S. xylosis; respectively.
 Ten isolates were tested for the presence of  7 resistance gens including:  mecA , tetK, blaZ , kan , ermC, icaD, bab gene. Seven isolates from the tested 10 (70%) having 4 resistance gens. The most detected gens are mecA tetK,  blaZ and ermC where it was detected in 90, 80, 60 and 90% respectively. Kan , icaD  and bab gens were detected in rate of 30.0 and 0 %; respectively.
In conclusion: CoNS could isolated from healthy and diseased chicken flocks as well as from chicken hatchery. The obtained isolates were multidrug either phenotypic and /or genotypic resistant. Good hygienic measures in both chicken farms  and  hatchery with monitoring of drug resistance of CoNS those act as source for resistance genes to bacterial pathogens and their importance to the poultry and public health are recommended .

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