Ankara Üniv Vet Fak Derg, 59, 107-114, 2012 Antibiotic resistance phenotypes of Salmonella isolates of broiler meat and chicken origin Seran TEMELLI1, Serpil KAHYA2, Aysegul EYIGOR1, Kamil Tayfun CARLI2 1 Department of Food Hygiene and Technology, and 2Department of Microbiology, Uludag University, Faculty of Veterinary Medicine, Bursa, Turkey. Summary: This study aims to determine the antibiotic resistance phenotypes of Salmonella isolates of broiler meat and chicken samples against a total of 23 antimicrobial agents. For this, 64 meat and 79 chicken Salmonella isolates, which were obtained from retail meat and farm samples analyzed in our laboratory from February 2006 to January 2009, were used. All Salmonella isolates were resistant to at least 4 antimicrobials tested, with the common highest resistance rates to erythromycin (100.0%), bacitracin (99.3%), and rifampicin (98.6%), regardless of the sample type. Additionally, meat isolates were 100.0% resistant to bacitracin, clindamycin, erythromycin, rifampicin, and chicken isolates were 100.0% resistant to erythromycin, spiramycin, penicillin G, doxycycline hydrochloride, and tetracycline. Four to 7 Multi Drug Resistant (MDR) Salmonella conformed 82.83% of all meat isolates, and 10, 12, 15, and 17 MDR Salmonella conformed 55.68% of all chicken isolates analyzed. The B/DA/E/RD and N/B/CT/E/SP/P/RD/DO/OT/TE resistances were the most common patterns as 35.94% and 13.92% within meat and chicken isolates, respectively. The considerably high resistance rates and MDR types to commonly used antimicrobial agents among the Salmonella isolates tested pose a significant risk factor for the treatment of foodborne Salmonella infections in humans. Keywords: Salmonella, chicken, broiler meat, antimicrobial resistance. Tavuk eti ve tavuk orijinli Salmonella izolatlarında antibiyotik dirençlilik fenotipleri Özet: Bu çalışmada tavuk eti ve tavuk orijinli Salmonella izolatlarında 23 antimikrobiyal ajana karşı dirençlilik fenotiplerinin belirlenmesi amacı ile perakende satış yerleri ve çiftlik örneklerinden elde edilen 64 adet et ve 79 adet tavuk Salmonella izolatı, Şubat 2006 ile Ocak 2009 arasında laboratuvarımızda analiz edildi. Tüm Salmonella izolatlarının, örnek tipi göz önünde bulundurulmaksızın, test edilen antimikrobiyalleden en yüksek direnç oranı ile sırası ile eritromisin’e (%100.0), basitrasin’e (%99.3) ve rifampisin’e (%98.6) olmak üzere en az 4 antimikrobiyale dirençli olduğu belirlendi. Ayrıca, et izolatlarının basitrasin, klindamisin, eritromisin, rifampisin’e; tavuk izolatlarının ise eritromisin, spiramisin, penisilin G, doksisiklin hidroklorür ve tetrasiklin’e %100.0 dirençli olduğu bulundu. Tüm et izolatlarının %82.83’ü 4 ile 7 Çoklu İlaç Direnci (ÇİD) gösterirken, tüm tavuk izolatlarının %55.68’i 10, 12, 15 ve 17 antimikrobiyale ÇİD gösterdiği belirlendi. Et izolatlarında %35.94 oranında ve tavuk izolatlarında ise %13.92 oranında olmak üzere en sık rastlanan ÇİD paternleri sırasıyla B/DA/E/RD ve N/B/CT/E/SP/P/RD/DO/OT/TE olarak bulundu. Salmonella izolatlarında karşılaşılan bu yüksek dirençlilik oranlarının ve ÇİD paternlerinin insanlardaki Salmonella infeksiyonlarının tedavisinde risk oluşturabileceği belirtildi. Anahtar sözcükler: Salmonella, tavuk, broyler eti, antimikrobiyal direnç Introduction emergence, persistence and spread of these antimicrobial Salmonella enterica serovars, the etiological agents resistant strains in the food chain. of foodborne salmonellosis worldwide, are carried by In recent years, there are several reports on chicken and transmitted to humans mainly by Salmonella isolates that are resistant to several contaminated broiler meat (19). Treatment of these types antimicrobial agents (Multi Drug Resistant - MDR) both of infections becomes limited as a consequence of the in the developed and developing countries from chicken rising antimicrobial resistance, which appears to be a meat (4, 15, 17, 18, 21, 22, 23), and from chickens (3, 5, direct result of acquiring these increasingly resistant 7, 10, 12). The emergence of these MDR Salmonella has strains from farm animals, particularly by the significant outcomes for the safety of the food supply, consumption of chicken meat acquiring Salmonella (9). namely chicken meat, directly as a source of MDR Strategies applied in antimicrobial use both for treatment Salmonella, and indirectly as a reservoir of antimicrobial and for prophylactic/growth promoting purposes in genetic elements that can be exchanged between chicken production had significant roles in the intestinal bacteria (2). Also as the human exposure to 108 Seran Temelli - Serpil Kahya - Aysegul Eyigor - Kamil Tayfun Carli these MDR Salmonella via the food supply increases, Cephazolin (KZ, 30 µg, Oxoid CT0011B), Ciprofloxacin infections can frequently become harder to treat (2). In (CIP, 1 µg, Oxoid CT0623B), Clindamycin (DA, 10 µg, our country, up to our knowledge, there are only a few Oxoid CT0015B), Colistin sulphate (CT, 10 µg, Oxoid studies indicating the presence of antibiotic resistance in CT0017B), Doxycycline hydrochloride (DO, 30 µg, Oxoid Salmonella isolated from chicken meat (13) and from CT0018B), Enrofloxacin (ENR, 5 µg, Oxoid CT0639B), chickens (11, 14), showing requirement of more data by Erythromycin (E, 15 µg, Oxoid CT0020B), Gentamicin further studies. (CN, 120 µg, Oxoid CT0794B), Neomycin (N, 30 µg, In this study, antibiotic resistance phenotypes of Oxoid CT0033B), Oxytetracycline (OT, 30 µg, Oxoid 143 Salmonella isolates of broiler meat and chicken CT0041B), Penicillin G (P, 10 units, Oxoid CT0043B), origin were determined against a total of 23 Rifampicin (RD, 5 µg, Oxoid CT0207B), Spiramycin antimicrobials, which are widely used in veterinary and (SP, 100 µg, Oxoid CT0232B), Streptomycin (S, 10 µg, human medicine. Oxoid CT0047B), Sulphamethoxazole/Trimethoprim 19:1 (SXT, 25 µg, Oxoid CT0052B), Tetracycline (TE, Materials and Methods 10 µg, Oxoid CT0053B). The reference bacterial strains Salmonella isolates: Sixty four retail broiler meat, E. coli (ATCC 25922) and S. aureus (ATCC 25923) and 79 chicken farm samples (41 cloacal swab, 7 were used as quality control strains following the intestine, 22 caecum and 9 gizzard), which were recommendations of CLSI (6). determined as positive for Salmonella in our laboratory from February 2006 to January 2009 were the sources of Results these isolates. Isolates obtained from these sources had All broiler meat isolates were found 100.0% been subjected to both biochemical identification by API resistant to bacitracin, clindamycin, erythromycin and 20E (Biomerieux, 20100, France), and serological rifampicin, regardless of the serogroups tested. All identification using Salmonella group-specific antisera serogroup based antimicrobial resistance rates are (Becton-Dickinson, USA). summarized in Table 1. Chicken isolates, which all Antimicrobial susceptibility test: Antimicrobial belonged to serogroup D, were found 100.0% resistant to profile of each Salmonella isolate was determined by the erythromycin, spiramycin, penicillin G, doxycycline disk agar diffusion method according to the guidelines of hydrochloride, and tetracycline. Details of resistances to the Clinical and Laboratory Standards Institute (6) as other antimicrobials were provided in Table 1. follows: A loopful of the Salmonella stock culture was All broiler meat isolates were found multi resistant streaked onto 7% sterile sheep blood added Blood Agar from 4 to 13 out of 15 antimicrobials tested. The highest Base No:2 plate (Oxoid, CM0271) and incubated at 37°C MDR rate (35.94%) belonged to the 4 MDR group, with for 24 h. One colony per plate was transferred into 5 ml a sole pattern as B/DA/E/RD, which was also the of Tryptone Soya Broth (Oxoid, CM0129) and was common pattern within all the broiler meat isolates. incubated at 37°C for 6 h. After turbidity adjustment to Resistances to other antimicrobials over this pattern were 0.5 McFarland by dilution, a sterile swab was dipped into given in detail in Table 2. The chicken isolates, which all the inoculum and streaked onto Mueller-Hinton Agar belonged to serogroup D, showed antimicrobial (Oxoid, CM0337) plate three times, where the plate was resistance ranging from 8 to 20 drugs tested. The highest turned 120° each time. Plates were allowed to dry MDR rate (17.72%) in chicken isolates was observed in keeping the lid slightly apart for 1 h. The commercial both 10 MDR and 17 MDR groups, where 11 out of 14 in antibiotic discs were placed in such a way that their 10 MDR showed a main pattern as N/B/CT/E/SP/P/ centers were at least 30 mm apart and at least 10 mm RD/DO/OT/TE, and 9 out of 14 in 17 MDR revealed a away from the edge of the plate. Plates were incubated at pattern as N/CL/KZ/EFT/B/CT/CIP/ENR/E/SP/AMC/ 37°C and examined at 18 and 24 h. Zone diameters of AMP/P/RD/DO/OT/TE (Table 3). complete inhibition were measured and the interpretation was done following the recommendation of the disc Discussion and Conclusion manufacturer. The 23 antimicrobial agents tested and The high (100.0%) antimicrobial resistance their corresponding concentrations were as follows: observed in all of the broiler meat isolates to bacitracin, Amikacin (AK, 30 µg, Oxoid CT0107B), Amoxycillin/ clindamycin, erythromycin and rifampicin is a unique Clavulanic acid (AMC, 30 µg, Oxoid CT0223B), finding, since in current literature there is no study, Ampicillin (AMP, 10 µg, Oxoid CT0003B), Apramycin which had tested these antimicrobials on this type of (APR, 15µg, Oxoid CT0545B), Bacitracin (B, 10 units, isolates. Among these antimicrobials, in our country, Oxoid CT0005B), Ceftiofur (EFT, 30 µg, Oxoid bacitracin is the only one used as feed supplement and not CT1751B), Cephalexin (CL, 30 µg, Oxoid CT0007B), used for treatment purposes in poultry. Also, erythromycin, Ankara Üniv Vet Fak Derg, 59, 2012 109 Table 1. Antimicrobial resistance results of Salmonella isolated from broiler meat and chicken samples. Tablo 1. Tavuk etleri ve tavuklardan izole edilen salmonellaların antimikrobiyal dirençlilik sonuçları. Antimicrobials Sero group Aminoglycosides Cephalosporins Cyclic Fluoro polypeptides quinolones Macrolides Penicillins Rifamycin Sulfonamide Tetracyclines (n) AK APR CN N S CL KZ EFT B CT CIP ENR DA E SP AMC AMP P RD SXT DO OT TE B (11) 0 2 0 0 11 2 1 1 11 11 1 11 0 0 0 C1 (4) 0 4 4 0 4 4 4 4 4 4 0 4 4 4 3 C2 (7) 1 5 6 5 7 2 0 2 7 7 5 7 1 2 5 D (27) 0 13 3 0 27 3 5 7 27 27 0 27 0 1 2 E1 (1) 0 1 0 0 1 1 0 0 1 1 0 1 0 0 0 E4 (12) 0 3 0 1 12 3 0 3 12 12 0 12 0 0 0 F (1) 0 1 1 1 1 1 1 1 1 1 1 1 1 1 0 G (1) 0 0 1 0 1 1 0 0 1 1 0 1 0 0 0 Sub total 1 29 15 7 64 17 11 18 64 64 7 64 6 8 10 (64) % 1.6 45.3 23.4 10.9 100.0 26.6 17.2 28.1 100.0 100.0 10.9 100.0 9.4 12.5 15.6 D (79) 6 12 0 65 35 38 37 27 78 75 46 43 79 79 33 35 79 77 6 79 76 79 % 7.6 15.1 0.0 82.3 44.3 48.1 46.8 34.2 98.7 94.9 58.2 54.4 100.0 100.0 41.8 44.3 100.0 97.5 7.6 100.0 96.2 100.0 Total (143) 1 94 50 44 142 92 57 61 143 42 141 12 87 86 % 0.7 65.7 34.9 30.8 99.3 64.3 39.9 42.7 100.0 29.4 98.6 8.4 60.8 60.1 AK, Amikacin; APR, Apramycin; CN, Gentamicin; N, Neomycin; S, Streptomycin; CL, Cephalexin; KZ, Cephazolin; EFT, Ceftiofur; B, Bacitracin; CT, Colistin sulphate; CIP, Ciprofloxacin; ENR, Enrofloxacin; DA, Clindamycin; E, Erythromycin; SP, Spiramycin; AMC, Amoxycillin/Clavulanic acid; AMP, Ampicillin; P, Penicillin G; RD, Rifampicin; SXT, Sulphamethoxazole/ Trimethoprim 19:1; DO, Doxycycline hydrochloride; OT, Oxytetracycline; TE, Tetracycline C h i c k e n M e a t S o u r c e 110 Seran Temelli - Serpil Kahya - Aysegul Eyigor - Kamil Tayfun Carli Table 2. Antimicrobial resistance patterns of broiler meat Salmonella isolates Tablo 2. Tavuk eti Salmonella izolatlarının antimikrobiyal dirençlilik paternleri No. resistant No. isolates and serogroup No. isolates with same Antimicrobials antimicrobial / total (%) pattern and serogroup CN N S KZ B CT CIP ENR DA E AMP RD SXT DO OT 4 7B, 9D, 7E4 / 23 (35.94) 23 BDE4 B DA E RD 1 B B CT DA E RD 7 D N B DA E RD 5 1B, 10D, 2E4 2 D B ENR DA E RD / 13 (20.31) 1 D S B DA E RD 1 E4 B CT DA E RD 1 E4 B ENR DA E RD 1 B N B CT DA E RD 1 B N B CIP DA E RD 1 B B ENR DA E AMP RD 1 C2 N B CT DA E RD 1 D B CT CIP DA E RD 6 3B, 1C2, 4D, 1E1, 1E4, 1G / 11 (17.18) 1 D B CIP ENR DA E RD 1 D N S B DA E RD 1 D N B DA E RD OT 1 E1 N B CT DA E RD 1 E4 N B ENR DA E RD 1 G S B CT DA E RD 1 C2 N S B CT DA E RD 2 D N B CIP ENR DA E RD 7 1C2, 3D, 2E4 / 6 (9.40) 1 D N B CT ENR DA E RD 1 E4 N B CT ENR DA E RD 1 E4 N KZ B CT DA E RD 8 2C2 / 2 (3.12) 2 C2 S KZ B DA E AMP RD OT 9 1C2 / 1 (1.56) 1 C2 N S KZ B DA E AMP RD OT 11 1C1, 1D / 2 (3.12) 1 C1 N S B CT CIP ENR DA E RD SXT DO 1 D N S B CT CIP ENR DA E RD DO OT 3 C1 N S B CT CIP ENR DA E RD SXT DO OT 12 3C1, 2C2 / 5 (7.81) 1 C2 CN N S KZ B ENR DA E AMP RD DO OT 1 C2 N S KZ B ENR DA E AMP RD SXT DO OT 13 1F / 1 (1.56) 1 F N S KZ B CT CIP ENR DA E AMP RD SXT DO CN, Gentamicin; N, Neomycin; S, Streptomycin; KZ, Cephazolin; B, Bacitracin; CT, Colistin sulphate; CIP, Ciprofloxacin; ENR, Enrofloxacin; DA, Clindamycin; E, Erythromycin; AMP, Ampicillin; RD, Rifampicin; SXT, Sulphamethoxazole/Trimethoprim 19:1; DO, Doxycycline hydrochloride; OT, Oxytetracycline Ankara Üniv Vet Fak Derg, 59, 2012 111 Table 3. Antimicrobial resistance patterns of chicken Salmonella isolates Tablo 3. Tavuk Salmonella izolatlarının antimikrobiyal dirençlilik paternleri No. resistant antimicrobial No. isolates (%) No. İsolates with Antimicrobials same pattern AK APR CN N S CL KZ EFT B CT CIP ENR E SP AMC AMP P RD SXT DO OT TE 8 2 (2.53) 1 S B E SP P RD DO TE 1 B CT E SP P RD DO OT TE 9 4 (5.06) 3 B CT E SP P RD DO OT TE 1 N CT E SP P RD DO OT TE 11 N B CT E SP P RD DO OT TE 10 14 (17.72) 1 N S B E SP P RD DO OT TE 1 S B CT E SP P RD DO OT TE 1 B CT CIP E SP P RD DO OT TE 2 N S B CT E SP P RD DO OT TE 1 N S B CIP E SP P RD DO OT TE 11 6 (7.59) 1 N B CT ENR E SP P RD DO OT TE 1 N B CT CIP ENR E SP P DO OT TE 1 N CL B CT E SP P RD DO OT TE 2 N B CT CIP ENR E SP P RD DO OT TE 1 N CL B CT ENR E SP P RD DO OT TE 1 APR N S B CT E SP P RD DO OT TE 12 8 (10.12) 1 APR N S B CT E SP P RD DO OT TE 1 AK N S B CT E SP P RD DO OT TE 1 N S B CT E SP P RD SXT DO OT TE 1 N KZ B CT CIP E SP P RD DO OT TE 2 N S B CT CIP ENR E SP P RD DO OT TE 13 5 (6.32) 2 AK N S B CT E SP P RD SXT DO OT TE 1 APR N S B CT E SP P RD SXT DO OT TE 1 N CL KZ B CT CIP ENR E SP AMP P RD DO TE 14 3 (3.79) 1 N S B CT CIP ENR E AMC P RD DO OT TE 1 AK APR CL KZ B CT CIP ENR E SP AMC AMP P RD DO OT TE 1 CL KZ B CT CIP ENR E SP AMC AMP P RD DO OT TE 1 N S B CT CIP ENR E SP AMP P RD SXT DO OT TE 1 S KZ B CT CIP ENR E SP AMP P RD SXT DO OT TE 15 8 (10.12) 1 N CL KZ EFT B CIP E SP AMC AMP P RD DO OT TE 1 N CL KZ EFT B CT CIP E SP AMC AMP P RD DO TE 1 AK APR N S CL KZ B CT E SP P RD DO OT TE 1 APR N S CL B CT CIP ENR E SP P RD DO OT TE 1 S CL KZ B CT CIP ENR E SP AMP P RD DO OT TE 16 5 (6.32) 3 N CL KZ B CT CIP ENR E SP AMC AMP P RD DO OT TE 2 CL KZ EFT B CT CIP ENR E SP AMC AMP P RD DO OT TE 9 N CL KZ EFT B CT CIP ENR E SP AMC AMP P RD DO OT TE 1 N S CL KZ EFT B CT CIP E SP AMC AMP P RD DO OT TE 17 14 (17.72) 1 N S CL KZ EFT B CT CIP ENR E SP AMC AMP P DO OT TE 1 N S CL KZ EFT B CT ENR E SP AMC AMP P RD DO OT TE 1 APR N S CL KZ B CT CIP ENR E SP AMC P RD DO OT TE 1 S CL KZ EFT B CT CIP ENR E SP AMC AMP P RD DO OT TE 5 N S CL KZ EFT B CT CIP ENR E SP AMC AMP P RD DO OT TE 18 7 (8.86) 1 APR S CL KZ EFT B CT CIP ENR E SP AMC AMP P RD DO OT TE 1 APR N CL KZ EFT B CT CIP ENR E SP AMC AMP P RD DO OT TE 19 2 (2.53) 2 APR N S CL KZ EFT B CT CIP ENR E SP AMC AMP P RD DO OT TE 20 1 (1.26) 1 AK APR N S CL KZ EFT B CT CIP ENR E SP AMC AMP P RD DO OT TE AK, Amikacin; APR, Apramycin; CN, Gentamicin; N, Neomycin; S, Streptomycin; CL, Cephalexin; KZ, Cephazolin; EFT, Ceftiofur; B, Bacitracin; CT, Colistin sulphate; CIP, Ciprofloxacin; ENR, Enrofloxacin; E, Erythromycin; SP, Spiramycin; AMC, Amoxycillin/Clavulanic acid; AMP, Ampicillin; P, Penicillin G; RD, Rifampicin; SXT, Sulphamethoxazole/Trimethoprim 19:1; DO, Doxycycline hydrochloride; OT, Oxytetracycline; TE, Tetracycline 112 Seran Temelli - Serpil Kahya - Aysegul Eyigor - Kamil Tayfun Carli which was being used as supplement and for treatment in sulphamethoxazole/trimethoprim 19:1 was relatively poultry between 1980s and 1990s, is not an antimicrobial lower than previously reported by Ishihara et al. (10) in of current use. The isolates were also checked for chicken isolates. resistance status against clindamycin and rifampicin, Among recent reports of antimicrobial resistance in specific drugs particularly used in human medicine, and Salmonella isolated from chicken meat and chickens, the it was interesting to find out high resistance against these results vary widely among antimicrobials tested and important antimicriobials in all the isolates tested. The according to the origin of the isolates. When our isolates’ intermediate resistance to neomycin, and relatively lower resistance results are compared based on the common but notable resistances to enrofloxacin, colistin sulphate, antimicrobials used in these studies, relatively lower streptomycin, ciprofloxacin, oxytetracycline, doxycycline resistance rates to streptomycin (3, 15, 17, 18, 23), hydrochloride, ampicillin, and sulphamethoxazole/ sulphamethoxazole/trimethoprim 19:1 (4, 10, 17, 22, 23) trimethoprim 19:1, all of which are the members of drug and to oxytetracycline (10) were found in our study to classes that have widely been used in poultry medicine those previously reported. and/or production for years were remarkable. Our results The resistance rates obtained in this study were higher than earlier reports of Miranda et al. (17) and are in parallel to the previous studies reporting resistance to Zewdu and Cornelius (23) for ciprofloxacin; of Capita et these antimicrobials, namely for streptomycin and al. (4) and Van et al. (21) for enrofloxacin; of Ishihara et ampicillin (15, 17, 18, 21, 22, 23), enrofloxacin (4,21), al. (10), Kang et al. (12), Kasimoglu et al. (13), Lestari et ciprofloxacin and sulphamethoxazole/trimethoprim 19:1 al. (15) and Yan et al. (22) for cephazolin; and of Bekele (4, 17, 22, 23). Also, resistance results to doxycycline and Ashenafi (3) for doxycycline hydochloride. There hydrochloride and oxytetracycline were similar to the were almost equivalent number of studies reporting previously reported tetracycline resistance results of higher (17, 18, 22, 23) and lower (10, 15, 16, 21) others (13, 15, 17, 21, 22, 23). resistances compared to our ampicillin resistance rates. The high resistance of our serogroup C1 meat The resistance of the Salmonella isolates in this isolates particularly to streptomycin, ciprofloxacin, study was substantially higher for the antimicrobials, sulphamethoxazole/trimethoprim 19:1 were similar to the which are in use for human and veterinary medicine for findings of Little et al. (16). For the serogroup C2 longer time, with the exceptions of the following drugs isolates’ resistances, two studies from the USA showed previously reported with lower resistance similar to ours: similarity to our results as: by Lestari et al. (15), who ampicillin (10, 14, 15, 16, 21), sulphamethoxazole/ found high resistance to ampicillin, oxytetracycline and trimethoprim 19:1 (12, 15), and gentamicin (11, 14). The streptomycin, and by Parveen et al. (18), who reported reasons behind these relatively lower resistances in our high resistance to cephazolin, ampicillin and oxytetracycline Salmonella isolates for these 3 antimicrobials, which also in their meat isolates of serovars belonging to serogroup have been used in the treatment of various poultry C2. Also, another study from Algeria reported high diseases for a long time need to be investigated in further resistance to tetracycline and streptomycin in their meat studies. isolates belonging to serovar C2 (7). These results Overall evaluation of the resistance rates of broiler indicate that presence of these types of isolates in meat meat and chicken isolates indicated prominent resistance causing human infections would definitely pose risk in to erythromycin, bacitracin, and rifampicin, the latter two treatments, since they show resistance to several antimicrobials with restricted use in large animal practice important groups of antimicrobials. (20). Also, results of 11 common antimicrobials tested The high antimicrobial resistance of the chicken for these isolates showed that resistance rates of the isolates to bacitracin, erythromycin and rifampicin in this chicken isolates were almost always higher than those of study is similar to the findings obtained for the broiler broiler meat isolates except for sulphamethoxazole/ meat isolates. Previously, high resistance to erythromycin trimethoprim 19:1. All these results imply that the in broiler Salmonella isolates was reported by Bekele and isolates showed resistance to one or more antimicrobial Ashenafi (3), who similarly had detected high resistance tested, except to gentamicin, to which all but one isolates results for penicillin G, doxycycline hydrochloride in were found susceptible. This very low overall resistance parallel to our findings. Also, the resistance rates to gentamicin (with 100% susceptibility in all chicken determined in this study for the chicken isolates were in Salmonella isolates) shows similarity to previous data by agreement with previous reports for tetracycline (5, 12), Kalender and Muz (11), and Kilinc and Aydin (14). oxytetracycline (10), ciprofloxacin and enrofloxacin (5), The significantly high antimicrobial resistance rates enrofloxacin and penicillin G (14), cephalexin and in our Salmonella isolates were probably an indication of cephazolin (3), streptomycin and ampicillin (3, 5, 12), their intense use in practice without paying required amoxycillin/clavulanic acid (3), and ceftiofur (10). The attention to the following issues: (I) indiscriminate use of resistance rate observed in the broiler isolates for antimicrobials with improper administration periods and Ankara Üniv Vet Fak Derg, 59, 2012 113 doses (8) both in poultry and human medicine (II) self- 19:1, doxycycline hydrochloride and oxytetracycline. medication by easy access to antimicrobials without This type of a tendency in the studied serogroups is an prescription (1) in human medicine, (III) use of sub- interesting note open to further genotype based therapeutic dose of antimicrobials for prophylactic/ investigations, due to the absence of serovar information nutritional purposes in poultry sector; (IV) unintended of our isolates, and since one serogroup is comprised of violations in withdrawal periods of antimicrobials in many serovars, which can definitely exhibit different poultry production. All these practices can cause antimicrobial resistance phenotypes, and even under a emergence and dissemination of resistant Salmonella in specific serovar, number of resistant antimicrobials can humans, livestock and their products, such as chicken vary in great extent for different isolates as seen in meat (19). previous reports (13, 21). Also, in the broiler meat versus Another very striking outcome of our study is that chicken isolate comparisons, limited to antimicrobials all of our broiler meat and chicken Salmonella isolates tested in both groups of isolates, revealed that there were were MDR to 4-13 out of 15, and 8-20 out of 22 substantially more chicken isolates (92.4%) than broiler antimicrobials tested, respectively. The 100% MDR to a meat isolates (25.0%) showing MDR with resistance to ≥ minimum of 4 antimicrobials that was detected in our 7 antimicrobials (data not shown in detail). At this point, study for the broiler meat isolates surpasses the MDR this finding should be left as entirely coincidental, since rates reported in similar recent studies as follows: MDR it is restricted to observations in these isolates. to ≥ 1: 62.1% (23), 88.9% (21); MDR to ≥ 2: 27.8% (21), The considerably high resistance rates and MDR 40% (4), 52.4% (15), 68.75% (13), 72.5% (18), 89.6% types to commonly used antimicrobial agents among the (22); MDR to ≥ 3: 35.7% (15), 53.4% (18). Within these Salmonella isolates tested in our study once more studies, several had results with MDR Salmonella indicated strict implementation of pertinent regulations in isolates with ≥4 antimicrobials still with lower rates conjunction with reliable control systems, to establish compared to ours as: 6.25% (13), 52.7% (22), 85.4% prudent use of these antimicrobials in veterinary and (17), and some indicated resistance in some of their human medicine. isolates up to 10 antimicrobials (15, 23), which is similar to our up to 13 MDR finding. MDR results of our References chicken Salmonella isolates showed that our 100% MDR 1. Acha PN, Szyfres B (2001): Zoonoses and Communicable rate (minimum to 8 antimicrobials) was higher than Diseases Common to Man and Animals. 3rd edn., previous reports of Elgroud et al. (7) and Ishihara et al. Washington DC: Pan American Health (10) (MDR to ≥2 antimicrobials: 51.7% and 91.3%, Organization,Vol.1, pp. 233-246. respectively), and of Bekele and Ashenafi (3) (MDR to 2. Angulo FJ, Nargund VN, Chiller TC (2004): Evidence ≥3 antimicrobials: 24.6%), who also reported resistance of an association between use of anti-microbial agents in food animals and anti-microbial resistance among up to 6 antimicrobials in their broiler Salmonella isolates, bacteria isolated from humans and the human health in contrast to our results. consequences of such resistance. J Vet Med B, 51, 374- The MDR pattern common to all meat isolates as 379. B/DA/E/RD, and the main pattern of N/B/CT/E/SP/P/ 3. Bekele B, Ashenafi M (2010): Distribution of drug RD/DO/OT/TE in most of the chicken isolates showed resistance among enterococci and Salmonella from poultry no one to one similarity/commonality to the previous and cattle in Ethiopia. Trop Anim Health Pro, 42, 857- reports on chicken meat (13, 15, 17, 18, 23) and chicken 864. (10, 12). As one should expect, this could be mainly 4. Capita R, Alonso-Calleja C, Prieto M (2007): related to the differences in the specific antimicrobials Prevalence of Salmonella enterica serovars and genovars from chicken carcasses in slaughterhouses in Spain. J used in different studies, serovar/serogroup differences of Appl Microbiol, 103, 1366-1375. the isolates, country or regional origin of the isolates, and 5. Chiu LH, Chiu CH, Horn YM, Chiou CS, Lee CY, Yeh the source or type of the isolate. CM, Yu CY, Wu CP, Chang CC, Chu C (2010): In our study, the number of antimicrobials/ Characterization of 13 multi-drug resistant Salmonella antimicrobial families that our broiler meat isolates were serovars from different broiler chickens associated with MDR to were questioned, and it was observed that those of human isolates. BMC Microbiol, 10, 86. serogroup B, D and E4 isolates showed relatively lower 6. Clinical and Laboratory Standards Institute (CLSI) MDR (4 to 6 antimicrobials in all B; 4 to 7 antimicrobials (2006): Performance Standards for Antimicrobial Disk th in all E4; 4 to 7 antimicrobials in all but one D), than C1 Susceptibility Tests. Approved Standard, 10 edn. Documents M02-A10, M7-A8, M100-S19, Vol. 26, No. 1. and C2 isolates. Additionally, most/all C1 and/or C2 Pennsylvania, PA, USA. serogroup isolates, with relatively higher MDRs (mostly 7. 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Appl Environ Microb, 73, 6885- Enteritidis isolated from chickens and humans in Korea. J 6890. Vet Med Sci, 71, 1433-1438. 22. Yan H, Li L, Alam MJ, Shinoda S, Miyoshi S, Shi L 13. Kasimoglu Dogru A, Ayaz ND, Gencay YE (2009): (2010): Prevalence and antimicrobial resistance of Serotype identification and antimicrobial resistance Salmonella in retail foods in Northern China. Int J Food profiles of Salmonella spp. isolated from chicken Microbiol, 143, 230-234. carcasses. Trop Anim Health Pro, 42, 893-897. 23. Zewdu E, Cornelius P (2009): Antimicrobial resistance 14. Kilinc U, Aydin F (2006): Antibiotic susceptibility of pattern of Salmonella serotypes isolated from food items Salmonella spp. isolated chicken from poultry enterprises and personnel in Addis Ababa, Ethiopia. Trop Anim in Kayseri region. J Health Sci, 15, 35-40. Health Pro, 41, 241-249. 15. Lestari SI, Han F, Wang F, Ge B (2009): Prevalence and antimicrobial resistance of Salmonella serovars in Geliş tarihi: 07.09.2011 / Kabul tarihi: 17.11.2011 conventional and organic chickens from Louisiana retail Address for correspondence: stores. J Food Prot, 72, 1165-1172. Prof. Dr. Aysegul Eyigor 16. Little CL, Richardson JF, Owen RJ, De Pinna E, Department of Food Hygiene and Technology Threlfall EJ (2008): Prevalence, characterisation and Faculty of Veterinary Medicine antimicrobial resistance of Campylobacter and Salmonella Uludag University 16059, Görükle Campus in raw poultry meat in the UK, 2003-2005. Int J Environ Bursa, Turkey Heal R, 18, 403-414. Email: aeyigor@uludag.edu.tr 17. Miranda JM, Mondragon AC, Martinez B, Guarddon Phone: +90.224.2941334 M, Rodriguez JA (2009): Prevalence and antimicrobial Fax: +90.224.294 1202 resistance patterns of Salmonella from different raw foods in Mexico. J Food Prot, 72, 966-971.