This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Huys, G.
Right arrow Articles by Swings, J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Huys, G.
Right arrow Articles by Swings, J.
Agricola
Right arrow Articles by Huys, G.
Right arrow Articles by Swings, J.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, January 2005, p. 574-579, Vol. 71, No. 1
0099-2240/05/$08.00+0     doi:10.1128/AEM.71.1.574-579.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Molecular Diversity and Characterization of Tetracycline-Resistant Staphylococcus aureus Isolates from a Poultry Processing Plant{dagger}

Geert Huys,1* Klaas D'Haene,1 Johan Van Eldere,2 Alexander von Holy,3 and Jean Swings1,4

Laboratory of Microbiology,1 BCCM/LMG Bacteria Collection, Ghent University, Ghent,4 Rega Institute, Department of Microbiology and Immunology, Katholieke Universiteit Leuven, Leuven, Belgium,2 School of Molecular and Cell Biology, University of the Witwatersrand, Wits, South Africa3

Received 4 June 2004/ Accepted 23 August 2004


arrow
ABSTRACT
 
DNA fingerprinting and molecular characterization showed that the tetracycline-resistant Staphylococcus aureus population of a South African poultry processing plant comprised one or possibly several tet(K)-containing endemic clones that contaminated chicken and machinery surfaces at all sampled processing stages. The tet(K) gene was transferable by filter mating to S. aureus recipient 80CR5 and was located on a pT181-like plasmid.


arrow
INTRODUCTION
 
Poultry processing plants (PPPs) are favorable environments for the survival and transmission of various commensal, spoilage, and potentially pathogenic bacteria throughout the human food chain. As one of the most predominant groups along the slaughtering and processing line of poultry, staphylococci have been recovered from air samples (13), neck skin of chicken carcasses (1, 15, 34), and equipment and machinery surfaces (15). After coagulase-negative Staphylococcus spp. (28), Staphylococcus aureus is the most widespread staphylococcus that can survive, colonize, and persist at various processing stages in commercial PPPs due to its expression of various key properties, including adhesion (7, 27) and chlorine resistance (6). In addition, S. aureus associated with poultry processing are also notorious as reservoir organisms of multiple antibiotic resistance traits (5, 16, 25, 31). Whereas there exists ample evidence demonstrating that clonal spread has significantly contributed to the dissemination of (multi)resistant staphylococci such as methicillin-resistant S. aureus in clinical settings (33, 36), it is far less clear if genotypically highly related or clonal lineages also occur among resistant S. aureus associated with food industry environments such as PPPs. The genotypic diversity of S. aureus from poultry abattoirs has been assessed by pulsed-field gel electrophoresis (PFGE) and/or plasmid profiling (11, 20), but very few studies have actually attempted to correlate strain types with antibiotic resistance patterns (5). Recently, Geornaras and von Holy (16) reported that most carcass and equipment surface S. aureus isolates from a South African PPP exhibited resistance to two tetracycline (TC) compounds. Triggered by the intensive and long-time use of chlortetracycline and oxytetracycline as growth promoters in poultry farming (44), TC resistance is one of the most frequently occurring resistance phenotypes among S. aureus from farming, processing, and storage environments of poultry. Combined with the fact that TC resistance in S. aureus is mainly disseminated by transmissible plasmids such as members of the pT181 family carrying the tet(K) gene (18) or by conjugative transposons such as Tn916 harboring the tet(M) gene (10), TC resistance thus provides an interesting marker to investigate the genotypic diversification of resistant Staphylococcus populations from food. As a follow-up to an earlier study (16), it was our objective to assess the genotypic diversity of TC-resistant (Tcr) S. aureus strains previously isolated from a South African PPP by repetitive DNA element-PCR (rep-PCR), PFGE, and plasmid profiling and to investigate the molecular basis of TC resistance in the different S. aureus genotypes.

The 38 S. aureus isolates under study originated from a PPP located in Sundra, South Africa, in which ca. 25,000 birds were slaughtered daily (16). Isolates were obtained from neck skins of carcasses after defeathering (CAD), evisceration (CAE), and immersion chilling (CAI), and from rubber fingers (RF) at the exit of the defeathering machine during four separate sampling surveys (designated 1, 2, 3, and 4) as described previously (16). Neck skin samples were composite samples made up from subsamples of 20 randomly selected carcasses collected at a specific step of the processing line within 2 min. A 20-g composite sample was homogenized in 180 ml of peptone-supplemented saline (PSS; 0.1% peptone and 0.85% saline) for 2 min. Rubber fingers were sampled after a routine cold water rinse by swabbing adjacent surface areas of ca. 5 cm2 for 30 s each by using five replicate swabs moistened in sterile PSS. The set of five swabs were suspended in a vial containing 10 ml of sterile neutralizing buffer by vigorous shaking for 30 s. For the isolation of S. aureus, all samples were subjected to the enrichment procedure of Bergdoll (4), after which 0.1 ml of the enriched sample was spread on Baird-Parker agar (Oxoid) and incubated at 37°C for 48 h. Up to three presumptive S. aureus isolates per sample plate were retained for antimicrobial susceptibility testing in which most isolates exhibited resistance to chlortetracycline and oxytetracycline (16). The identity of these isolates as S. aureus was confirmed in the present study using the ID 32 STAPH identification system (bioMérieux) according to the manufacturer's instructions. MICs of TC and minocycline were determined by microbroth dilution with cation-adjusted Mueller-Hinton II broth (Becton-Dickinson catalog no. 212322), including control strain S. aureus LMG 10147 (ATCC 29213 from the American Type Culture Collection) according to guidelines of the National Committee for Clinical Laboratory Standards (NCCLS) (30). Additional phenotypic resistances were determined with agar disk diffusion by using the following disks: gentamicin (10 µg), ampicillin (10 µg), rifampin (30 µg), kanamycin (30 µg), erythromycin (15 µg), chloramphenicol (30 µg), and methicillin (5 µg). Inhibition zones were interpreted according to NCCLS guidelines (30). For the purpose of rep-PCR fingerprinting and PCR detection assays, total genomic DNA was prepared by using a protocol based on the guanidium thiocyanate method of Pitcher et al. (37). Isolation of plasmid DNA was based on conventional alkaline lysis (3). rep-PCR fingerprinting with the (GTG)5 primer 5'-GTGGTGGTGGTGGTG-3' [(GTG)5-PCR] (17), PFGE analysis with SmaI (42) using a clamped homogeneous electric fields (CHEF) Mapper system (Bio-Rad, Hercules, Calif.), and plasmid profiling in 0.7% agarose at 100 V for 3.5 h (3) were performed as described previously. Digitized DNA fingerprinting data were analyzed and compared by using BioNumerics software v3.5 (Applied Maths, St-Martens-Latem, Belgium). For all PCR detection assays, a PCR core mix (total volume, 50 µl) was used consisting of 1x PCR buffer (Applied Biosystems, Warrington, United Kingdom), deoxynucleoside triphosphates (dATP, dCTP, dGTP, and dTTP) (Applied Biosystems) at a concentration of 200 µM each, 1 U of AmpliTaq DNA polymerase (Applied Biosystems), and 20 pmol of each primer (Sigma-Genosys, Ltd., Cambridgeshire, United Kingdom). A 50-ng portion of intact total DNA was used as a PCR template. For all isolates, the presence of the efflux genes tet(K) and tet(L) and of tet genes of the ribosomal protection (RP) family was assessed. One RP-positive isolate was further subjected to PCR detection of tet(M) and tet(O), and for the tet(M)-positive isolate the presence of conjugative transposons of the Tn916-Tn1545 family was determined by using primers targeting the integrase gene int-Tn1545. Erythromycin-resistant isolates were screened for the presence of staphylococcal erm(A) and erm(C) genes. Details on the PCR primers and positive controls for tet and erm gene detection are given in Table 1. All PCR amplifications were performed in a GeneAmp 9600 PCR system (Perkin-Elmer) by using the following temperature program: an initial denaturation at 94°C for 5 min, followed by 30 cycles of 94°C for 1 min, annealing (see Table 1) for 1 min, and 72°C for 2 min, with a final extension step at 72°C for 10 min. For detection of RP-type tet genes with primers Ribo2-FW and Ribo2-RV, the following touchdown PCR program was used: initial denaturation at 94°C for 5 min, followed by 22 cycles of denaturation at 94°C for 30s, annealing for 30 s with 1°C decrements at 72 to 50°C, and extension at 72°C for 30 s; 20 cycles of 94°C for 30 s, 50°C for 30 s, and 72°C for 30 s; and a final extension at 72°C for 7 min. PCR amplicons were checked electrophoretically on 1% agarose and visualized by using ethidium bromide fluorescence. A selection of genotypically diverse Tcr isolates was included in conjugation experiments with the TC-susceptible recipient S. aureus 80CR5 (14). The protocol was based on a previously described filter-mating procedure (22) in which overnight-grown cultures of donor and recipient were mixed in 1:1 and 1:3 ratios and filtered through a sterile membrane filter with a pore size of 0.45 µm (MF-Millipore membrane filter HAWP 2500; Millipore, Bedford, Mass.). After a filter rinsing with 2 ml of sterile peptone physiological saline (PPS) solution (8.5 g of NaCl and 1 g of neutralized bacteriological peptone [Oxoid]/liter), filters were incubated on brain heart infusion agar (Difco) for 24 h at 37°C and, after mating, the cells were washed from the filter with 2 ml of PPS. Transconjugants were selected by plating serial dilutions in PPS of the mating suspension on brain heart infusion agar supplemented with 10 µg of TC, 200 µg of rifampin, and 100 µg of fusidic acid/ml. Likewise the control plates containing individual donor and recipient strains, mating plates were incubated at 37°C for 24 to 72 h. Presumptive transconjugants were confirmed by disk diffusion and MIC testing, (GTG)5-PCR and plasmid profiling, and PCR-based detection of tet genes as described above. The presence of plasmids belonging to the pT181 family was verified by enzymatic digestion of the plasmid content of selected 80CR5 transconjugants with HindIII (9.38 U/µg of DNA) according to the manufacturer's instructions (Amersham Pharmacia Biotech). Plasmid restriction fragments were extracted and purified from an 1.5% agarose gel electrophoresed at 70 V for 2.5 h by using the Nucleospin kit (Macherey-Nagel, Düren, Germany) and were subsequently used as a template DNA for PCR detection of tet(K) as described above.


View this table:
[in this window]
[in a new window]
  		TABLE 1. Primers used for PCR detection of antibiotic resistance and int genes

Prior to studying the genotypic diversity of S. aureus isolates originating from a South African PPP (16), the presence of TC resistance and other resistance phenotypes was investigated by using MIC and disk diffusion testing. Based on a MIC cutoff value for resistance to tetracyclines of ≥16 µg/ml (30), 31 of the 38 S. aureus PPP isolates were considered Tcr (MIC range, 32 to 128 µg/ml), but all isolates were classified as minocycline susceptible (MIC range, <0.5 to 4 µg/ml) (Fig. 1). In disk diffusion testing, the 38 isolates were also uniformly susceptible to gentamicin, kanamycin, rifampin, chloramphenicol, and methicillin, whereas susceptibility to ampicillin and erythromycin was variable (Fig. 1). Genotyping with the rapid DNA fingerprinting method (GTG)5-PCR revealed that all but two of the 38 isolates grouped into six clusters containing two or more isolates, but this set of isolates was further reduced to 27 potentially unique strains when isolates originating from the same sample plate and displaying indistinguishable (GTG)5-PCR fingerprints and plasmid profiles were considered as duplicates. This dereplication step resulted in the delineation of four (GTG)5-PCR clusters (A to D) at a ≥85% Pearson correlation that grouped strains isolated at different processing stages and/or during different surveys (Fig. 1), whereas four strains remained ungrouped. Tcr strains of clusters A, C, and D were clearly different from the TC susceptible (MIC < 4 µg/ml) strains SA 04 and 37 and cluster B members. Overall, strains within each of these four clusters exhibited highly similar if not identical PFGE patterns, indicating that they are clonally related. This is in particular the case for the large cluster C that comprised the majority of the Tcr strains (n = 15), including strain SA 23 that may represent a subclonal variant within this cluster as demonstrated by its slightly atypical (GTG)5-PCR and PFGE fingerprints. The fact that members of cluster C were recovered from CAD and CAI samples during surveys 2 to 4 and surveys 1 to 4, respectively, and from RF samples during surveys 2 and 3 seems to indicate that these strains represent a resident or endemic clonal genotype within the PPP system. Although no samples were analyzed from the final processing steps such as carcass packaging, it can be speculated that this Tcr S. aureus clone was probably disseminated throughout the entire processing line and may thus end up in the final product. Previously, Dodd et al. (11) reported that the S. aureus populations from poultry carcasses and from equipment surfaces were markedly different on the basis of plasmid profiling. In the present study, all members of cluster C shared three plasmid bands (with estimated sizes of >16 kb, 4.2 to 4.4 kb, and <2 kb, respectively), but some strains also harbored additional plasmids or exhibited erythromycin resistance (Fig. 1). These findings again highlight that plasmid profiling cannot function as a stand-alone method to study bacterial population diversity but needs to be combined polyphasically with more robust DNA fingerprinting methods such as (GTG)5-PCR and PFGE. In contrast to cluster C, plasmid profiles and resistance phenotypes were highly similar or identical in clusters A (from CAI samples), B (from RF samples), and D (from CAD, CAE, and CAI samples). Although the strains within each of these three clusters were isolated from various sampling points and/or during different surveys, it is not possible to hypothesize that clusters A, B, or D represent additional S. aureus clonal genotypes within the PPP system given the low number of strains per cluster.



View larger version (68K):
[in this window]
[in a new window]
  		FIG. 1. Dendrogram based on clustering of digitally inverted (GTG)5-PCR fingerprints of 27 dereplicated S. aureus PPP isolates, with adjacent the corresponding SmaI macrorestriction and plasmid profiles. Four (GTG)5-PCR clusters (A to D) were delineated at 85% Pearson product-moment correlation. The dendrogram was obtained by using the unweighted paired group method with arithmetic averages. Sample codes consist of the source abbreviation (as defined in the text), followed by the sampling survey number (1 to 4). Strains that could successfully transfer TC resistance to recipient 80CR5 by filter mating have underlined numbers, and the plasmids that were acquired by 80CR5 in these matings are indicated by an asterisk at the top left of the respective plasmid band. The bold arrow below indicates the pT181-like 4.2- to 4.4-kb plasmid common to all tet(K)-containing strains. Strain numbers in boldface, i.e., SA 07, 08, 17, 23, and 34, were deposited in the public BCCM/LMG Bacteria Collection, Ghent University, Ghent, Belgium (http://www.belspo.be/bccm/db/bacteria_search.htm) as LMG 22522, 22523, 22524, 22525, and 22526, respectively. nd, none of the tested tet or erm genes were detected. AM, ampicillin; ER, erythromycin; MC, minocycline.

In the second part of the study, we aimed to determine the molecular basis of TC resistance in strains of clusters A, C, and D and the ungrouped strains. First, the presence of the four specific TC resistance genes thus far found in staphylococci, i.e., the efflux genes tet(K) and tet(L) and the RP-type genes tet(M) and tet(O) (8) was verified. The majority of the dereplicated Tcr S. aureus strains (n = 22) in the present study possessed tet(K), whereas one strain (SA 34) contained both tet(L) and tet(M). The fact that tet genes of the RP type such as tet(M) offer protection against both TC and minocycline was reflected by the higher MIC for minocycline of strain SA 34 (4 µg/ml) compared to the MICs of the tet(K)-containing strains (MIC < 0.5 µg/ml). Whereas the genes tet(K) and tet(M) have been repeatedly reported to occur together in strains of S. aureus (41, 43), strain SA 34 probably represents a rare case of a tet(L)/tet(M) combination in staphylococci. The tet(K) gene was detected in all members of the three Tcr (GTG)5-PCR clusters A, C, and D but, as expected, was not present in the TC-susceptible strains. Mainly because of its omnipresence in the widely disseminated cluster C strains, our data suggest that tet(K) has been established as an endemic resistance determinant in the PPP system and that various points of the processing line can be considered as potential reservoirs of TC resistance. In the five Tcr strains that also exhibited erythromycin resistance, tet genes were joined by the widespread erm(C) gene (Fig. 1). It is noteworthy that this gene has previously been shown to be located on small staphylococcal plasmids that were transferable from poultry to human clinical strains of S. aureus presumably by transformation (25).

The wide distribution of tet(K) and tet(M) among S. aureus strains has been linked to the fact that these genes are located on mobile genetic elements such as small plasmids and conjugative transposons (8), respectively. The only tet(M)-carrying strain in the present study, i.e., SA 34, was found to contain the transposon integrase gene int of the Tn916-Tn1545 family, indicating that the tet(M) gene of this strain is integrated in a conjugative transposon (10). From plasmid profiling, it was observed that all tet(K)-positive strains shared a plasmid with an estimated size of 4.2 to 4.4 kb which could indicate the presence of a pT181-like plasmid. The tet(K)-containing plasmid pT181 (GenBank accession no J01764) is regarded as the prototype of a family of small (4.3- to 4.7-kb) naturally occurring transmissible plasmids that are known to occur not only in clinical S. aureus (32) but also in Tcr Staphylococcus strains from environmental origins such as polluted waters (24) and wild rodents and insectivores (19). Filter-mating experiments with 11 selected donor isolates from (GTG)5-PCR clusters A, C, and D demonstrated that three isolates of cluster C and two isolates of cluster D were able to transfer tet(K) to the plasmid-free recipient strain 80CR5 at frequencies in the range of 10–7 to 10–8 per recipient. Plasmid profiling showed that all confirmed 80CR5 transconjugants had received the small 4.2- to 4.4-kb plasmid together with one or more additional plasmids (Fig. 1). Restriction enzyme analysis of the 4.2- to 4.4-kb plasmid from these transconjugants with HindIII yielded three fragments with estimated sizes of 0.5, 1.5, and 2.4 kb (data not shown) which matches with the HindIII restriction map of pT181 composed of 0.56-, 1.53-, and 2.35-kb fragments, respectively (26). Moreover, the finding that tet(K) was detected by PCR in all purified extracts of the 2.35-kb fragment which is known to contain the complete tet(K) gene in pT181 (18) suggests that the small plasmid common to all tet(K)-positive S. aureus isolates is a member of the pT181 family. In addition to previously reported food-associated sources such as the skin of pigs (38) and raw milk cheeses and meat products (35), our data provide possible evidence that PPP environments are also among the natural reservoirs of pT181 plasmids. The fact that pT181 and analogous plasmids are not self-transmissible (26) but can be mobilized by conjugative plasmids suggests that further work beyond the scope of the present study such as the molecular dissection of the additional plasmid(s) acquired by 80CR5 transconjugants is needed to unravel the transfer mechanism of pT181(-like) plasmids by S. aureus PPP isolates.

In conclusion, molecular typing and characterization showed that the Tcr S. aureus population of the investigated PPP system consisted of one or possibly several tet(K)-containing endemic clones that contaminated chicken and machinery surfaces at all sampled processing stages. To our knowledge, this is the first study to demonstrate that tet(K)-harboring plasmids of the pT181 family can also be disseminated by environmental S. aureus clones. Possibly, such clonal genotypes may represent important sources of pT181 that have contributed to the epidemiologically successful integration of this plasmid into the staphylococcal cassette chromosome mec (SCCmec) of the globally transmitted methicillin-resistant S. aureus clonotype III-A (21). In this respect, it would certainly be useful to aim future monitoring studies at the genetic diversification of Tcr S. aureus clones associated with the production and processing of food into carriers of multiple resistance elements.


arrow
ACKNOWLEDGMENTS
 
This study was supported by the Fund for Scientific Research-Flanders (Belgium; F.W.O.-Vlaanderen; contract G.0309.01). G.H. is a postdoctoral fellow of the Fund for Scientific Research-Flanders.

We thank G. Dasen (Institut für Lebensmittelwissenschaft, Zürich, Switzerland) and I. Klare (Robert Koch Institute, Wernigerode Branch, Germany) for the gifts of strains S. aureus 80CR5 and 694/01, respectively.


arrow
FOOTNOTES
 
* Corresponding author. Mailing address: Laboratory of Microbiology, Ghent University, K.L. Ledeganckstr. 35, B-9000 Ghent, Belgium. Phone: 32-9-2645131. Fax: 32-9-2645092. E-mail: geert.huys{at}UGent.be. Back

{dagger} This study is dedicated to Emily Huys. Back


arrow
REFERENCES
 
    1
  1. Aburuwaida, A. S., W. N. Sawaya, B. H. Dashti, M. Murad, and H. A. Alothman. 1994. Microbiological quality of broilers during processing in a modern commercial slaughterhouse in Kuwait. J. Food Prot. 57:887-892.
    2. 2
  2. Aminov, R. I., N. Garrigues-Jeanjean, and R. I. Mackie. 2001. Molecular ecology of tetracycline resistance: development and validation of primers for detection of tetracycline resistance genes encoding ribosomal protection proteins. Appl. Environ. Microbiol. 67:22-32.[Abstract/Free Full Text]
    3. 3
  3. Anderson, D. G., and L. L. McKay. 1983. Simple and rapid method for isolating large plasmid DNA from lactic streptococci. Appl. Environ. Microbiol. 46:549-552.[Abstract/Free Full Text]
    4. 4
  4. Bergdoll, M. S. 1989. Staphylococcus aureus, p. 463-523. In M. P. Doyle (ed.), Foodborne bacterial pathogens. Marcel Dekker, New York, N.Y.
    5. 5
  5. Bertolatti, D., F. G. O'Brien, and W. B. Grubb. 2003. Characterization of drug-resistant Staphylococcus aureus isolated from poultry processing plants in Western Australia. Int. J. Environ. Health Res. 13:43-54.[CrossRef][Medline]
    6. 6
  6. Bolton, K. J., C. E. R. Dodd, G. C. Mead, and W. M. Waites. 1988. Chlorine resistance of strains of Staphylococcus aureus isolated from poultry-processing plants. Lett. Appl. Microbiol. 6:31-34.
    7. 7
  7. Chaffey, B. J., and W. M. Waites. 1987. The adhesion of Staphylococcus aureus isolates from poultry-processing plants. J. Appl. Bacteriol. 63:R17-R17.
    8. 8
  8. Chopra, I., and M. Roberts. 2001. Tetracycline antibiotics: mode of action, applications, molecular biology, and epidemiology of bacterial resistance. Microbiol. Mol. Biol. Rev. 65:232-260.[Abstract/Free Full Text]
    9. 9
  9. Clermont, D., O. Chesneua, G. DeCespedes, and T. Horaud. 1997. New tetracycline resistance determinants coding for ribosomal protection in streptococci and nucleotide sequence of tet(T) isolated from Streptococcus pyogenes A498. Antimicrob. Agents Chemother. 41:112-116.[Abstract]
    10. 10
  10. Clewell, D. B., S. E. Flannagan, and D. D. Jaworski. 1995. Unconstrained bacterial promiscuity: the Tn916-Tn1545 family of conjugative transposons. Trends Microbiol. 3:229-236.[CrossRef][Medline]
    11. 11
  11. Dodd, C. E. R., B. J. Chaffey, and W. M. Waites. 1988. Plasmid profiles as indicators of the source of contamination of Staphylococcus aureus endemic within poultry-processing plants. Appl. Environ. Microbiol. 54:1541-1549.[Abstract/Free Full Text]
    12. 12
  12. Doucet-Populaire, F., P. Trieu-Cuot, I. Dosbaa, A. Andremont, and P. Courvalin. 1991. Inducible transfer of conjugative transposon Tn1545 from Enterococcus faecalis to Listeria monocytogenes in the digestive tracts of gnotobiotic mice. Antimicrob. Agents Chemother. 35:185-187.[Abstract/Free Full Text]
    13. 13
  13. Ellerbroek, L. 1997. Airborne microflora in poultry slaughtering establishments. Food Microbiol. 14:527-531.[CrossRef]
    14. 14
  14. Engel, H. W., N. Soedirman, J. A. Rost, W. J. van Leeuwen, and J. D. van Embden. 1980. Transferability of macrolide, lincomycin, and streptogramin resistances between groups A, B, and D streptococci, Streptococcus pneumoniae, and Staphylococcus aureus. J. Bacteriol. 142:407-413.[Abstract/Free Full Text]
    15. 15
  15. Geornaras, I., A. Dejesus, E. Vanzyl, and A. von Holy. 1995. Microbiological survey of a South-African poultry-processing plant. J. Basic Microbiol. 35:73-82.[Medline]
    16. 16
  16. Geornaras, I., and A. von Holy. 2001. Antimicrobial susceptibilities of isolates of Staphylococcus aureus, Listeria species and Salmonella serotypes associated with poultry processing. Int. J. Food Microbiol. 70:29-35.[CrossRef][Medline]
    17. 17
  17. Gevers, D., G. Huys, and J. Swings. 2001. Applicability of rep-PCR fingerprinting for identification of Lactobacillus species. FEMS Microbiol. Lett. 205:31-36.[CrossRef][Medline]
    18. 18
  18. Guay, G. G., S. A. Khan, and D. M. Rothstein. 1993. The tet(K) gene of plasmid pT181 of Staphylococcus aureus encodes an efflux protein that contains 14 transmembrane helices. Plasmid 30:163-166.[CrossRef][Medline]
    19. 19
  19. Hauschild, T., C. Kehrenberg, and S. Schwarz. 2003. Tetracycline resistance in staphylococci from free-living rodents and insectivores. J. Vet. Med. Series B Infect. Dis. Vet. Publ. Health. 50:443-446.
    20. 20
  20. Hennekinne, J. A., A. Kerouanton, A. Brisabois, and M. L. De Buyser. 2003. Discrimination of Staphylococcus aureus biotypes by pulsed-field gel electrophoresis of DNA macro-restriction fragments. J. Appl. Microbiol. 94:321-329.[CrossRef][Medline]
    21. 21
  21. Hiramatsu, K., L. Cui, M. Kuroda, and T. Ito. 2001. The emergence and evolution of methicillin-resistant Staphylococcus aureus. Trends Microbiol. 9:486-493.[CrossRef][Medline]
    22. 22
  22. Huys, G., K. D'Haene, J.-M. Collard, and J. Swings. 2004. Prevalence and molecular characterization of tetracycline resistance in Enterococcus isolates from food. Appl. Environ. Microbiol. 70:1555-1562.[Abstract/Free Full Text]
    23. 23
  23. Jensen, L. B., N. Frimodt-Moller, and F. M. Aarestrup. 1999. Presence of erm genes classes in gram-positive bacteria of animal and human origin in Denmark. FEMS Microbiol. Lett. 170:151-158.[CrossRef][Medline]
    24. 24
  24. Kessie, G., M. Ettayebi, A. M. Haddad, A. M. Shibl, F. J. Al-Shammary, A. F. Tawfik, and M. N. Al-Ahdal. 1998. Plasmid profile and antibiotic resistance in coagulase-negative staphylococci isolated from polluted water. J. Appl. Microbiol. 84:417-422.[CrossRef][Medline]
    25. 25
  25. Khan, S. A., M. S. Nawaz, A. A. Khan, and C. E. Cerniglia. 2000. Transfer of erythromycin resistance from poultry to human clinical strains of Staphylococcus aureus. J. Clin. Microbiol. 38:1832-1838.[Abstract/Free Full Text]
    26. 26
  26. Khan, S. A., and R. P. Novick. 1983. Complete nucleotide sequence of pT181, a tetracycline-resistance plasmid from Staphylococcus aureus. Plasmid 10:251-259.[CrossRef][Medline]
    27. 27
  27. Mead, G. C., C. Gibson, and D. B. Tinker. 1995. A model system for the study of microbial colonization in poultry defeathering machines. Lett. Appl. Microbiol. 20:134-136.
    28. 28
  28. Mead, G. C., and M. J. Scott. 1994. Coagulase-negative staphylococci and coliform bacteria associated with mechanical defeathering of poultry carcasses. Lett. Appl. Microbiol. 18:62-64.[CrossRef]
    29. 29
  29. Morse, S. A., S. R. Johnson, J. W. Biddle, and M. C. Roberts. 1986. High-level tetracycline resistance in Neisseria gonorrhoeae is a result of acquisition of streptococcal tetM determinant. Antimicrob. Agents Chemother. 30:664-670.[Abstract/Free Full Text]
    30. 30
  30. National Committee for Clinical Laboratory Standards. 2003. Performance standards for antimicrobial susceptibility testing. Thirteenth informational supplement. Approved standard M100-S13. National Committee for Clinical Laboratory Standards, Wayne, Pa.
    31. 31
  31. Nawaz, M. S., S. A. Khan, A. A. Khan, F. M. Khambaty, and C. E. Cerniglia. 2000. Comparative molecular analysis of erythromycin-resistance determinants in staphylococcal isolates of poultry and human origin. Mol. Cell. Probes 14:311-319.[CrossRef][Medline]
    32. 32
  32. Needham, C., M. Rahman, K. G. H. Dyke, and W. C. Noble. 1994. An investigation of plasmids from Staphylococcus aureus that mediate resistance to mupirocin and tetracyline. Microbiology 140:2577-2583.[Abstract/Free Full Text]
    33. 33
  33. Oliveira, D. C., A. Tomasz, and H. de Lencastre. 2001. The evolution of pandemic clones of methicillin-resistant Staphylococcus aureus: identification of two ancestral genetic backgrounds and the associated mec elements. Microb. Drug Resist. 7:349-361.[CrossRef][Medline]
    34. 34
  34. Olivier, M., C. M. Veary, T. E. Cloete, and A. von Holy. 1996. Microbiological status of selected chicken carcasses from a nonautomated poultry processing plant. J. Basic Microbiol. 36:41-49.[Medline]
    35. 35
  35. Perreten, V., N. Giampa, U. Schuler-Schmid, and M. Teuber. 1998. Antibiotic resistance genes in coagulase-negative staphylococci isolated from food. Syst. Appl. Microbiol. 21:113-120.[Medline]
    36. 36
  36. Pfaller, M. A., J. Acar, R. N. Jones, J. Verhoef, J. Turnidge, and H. S. Sader. 2001. Integration of molecular characterization of microorganisms in a global antimicrobial resistance surveillance program. Clin. Infect. Dis. 32:S156-S167.
    37. 37
  37. Pitcher, D. G., N. A. Saunders, and R. J. Owen. 1989. Rapid extraction of bacterial genomic DNA with guanidium thiocyanate. Lett. Appl. Microbiol. 8:151-156.
    38. 38
  38. Schwarz, S., and W. C. Noble. 1994. Tetracycline resistance genes in staphylococci from the skin of pigs. J. Appl. Bacteriol. 76:320-326.[Medline]
    39. 39
  39. Sougakoff, W., B. Papadopoulou, P. Nordmann, and P. Courvalin. 1987. Nucleotide sequence and distribution of gene tet(O) encoding tetracycline resistance in Campylobacter coli. FEMS Microbiol. Lett. 44:153-159.
    40. 40
  40. Strommenger, B., C. Kettlitz, G. Werner, and W. Witte. 2003. Multiplex PCR assay for simultaneous detection of nine clinically relevant antibiotic resistance genes in Staphylococcus aureus. J. Clin. Microbiol. 41:4089-4094.[Abstract/Free Full Text]
    41. 41
  41. Trzcinski, K., B. S. Cooper, W. Hryniewicz, and C. G. Dowson. 2000. Expression of resistance to tetracyclines in strains of methicillin-resistant Staphylococcus aureus. Antimicrob. Agents Chemother. 45:763-770.
    42. 42
  42. Van Eldere, J., W. E. Peetermans, M. Struelens, A. Deplano, and H. Bobbaers. 2000. Polyclonal staphylococcal endocarditis caused by genetic variability. Clin. Infect. Dis. 31:24-30.[CrossRef][Medline]
    43. 43
  43. Warsa, U., M. Nonoyama, T. Ida, R. Okamoto, T. Okubo, C. Shimauchi, A. Kuga, and M. Inoue. 1996. Detection of tet(K) and tet(M) in Staphylococcus aureus of Asian countries by the polymerase chain reaction. J. Antibiot. 49:1127-1132.[Medline]
    44. 44
  44. Witte, W. 2000. Selective pressure by antibiotic use in livestock. Int. J. Antimicrob. Agents 16:S19-S24.
    45. 45
  45. Zilhao, R., B. Papadopoulou, and P. Courvalin. 1988. Occurrence of the Campylobacter resistance gene tet(O) in Enterococcus and Streptococcus spp. Antimicrob. Agents Chemother. 32:1793-1796.[Abstract/Free Full Text]

Applied and Environmental Microbiology, January 2005, p. 574-579, Vol. 71, No. 1
0099-2240/05/$08.00+0     doi:10.1128/AEM.71.1.574-579.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Pepe, O., Blaiotta, G., Bucci, F., Anastasio, M., Aponte, M., Villani, F. (2006). Staphylococcus aureus and Staphylococcal Enterotoxin A in Breaded Chicken Products: Detection and Behavior during the Cooking Process.. Appl. Environ. Microbiol. 72: 7057-7062 [Abstract] [Full Text]  
  • Malhotra-Kumar, S., Lammens, C., Piessens, J., Goossens, H. (2005). Multiplex PCR for Simultaneous Detection of Macrolide and Tetracycline Resistance Determinants in Streptococci. Antimicrob. Agents Chemother. 49: 4798-4800 [Abstract] [Full Text]  

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Huys, G.
Right arrow Articles by Swings, J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Huys, G.
Right arrow Articles by Swings, J.
Agricola
Right arrow Articles by Huys, G.
Right arrow Articles by Swings, J.

Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»