Biochemical and molecular characterization of erthromycin-resistant avian Staphylococcus spp. isolated from chickens.
The epidemiology of the two common erythromycin-resistant methylase (erm) genes ermC and ermA was analyzed in 12 coagulase-negative Staphylococcus spp. and 34 coagulase-positive Staphylococcus spp. isolated from chicken. Southern hybridization indicated that only 2 of the 12 coagulase-negative Staphylococcus spp. strains contained the ermC gene on the plasmid; 1 strain of Staphylococcus xylosus harbored the ermC gene on a 2.5-kb plasmid, and 1 strain of Staphylococcus cohnii harbored the gene on a 4.0-kb plasmid. Twelve of the 34 strains of Staphylococcus aureus contained the ermC gene. Eleven of these strains had the ermC gene on a 2.5-kb plasmid, and 1 strain had the gene on a 4.0-kb plasmid. Ten of the 12 coagulase-negative Staphylococcus spp. and 22 of the 34 coagulase-positive Staphylococcus spp. harbored the ermA gene exclusively on the chromosome. Two different ermA EcoRI restriction fragment length polymorphisms (RFLP) were identified. A majority of the isolates was found to have two chromosomal inserts (8.0- and 6.2-kb EcoRI fragments) of ermA. One strain of S. aureus had different chromosomal inserts (6.4- and 5.8-kb EcoRI fragments) of ermA. Our results indicate that either the ermC or ermA gene, homologous to those described in human isolates, was present in all avian Staphylococcus spp. and that ermA was the predominant gene in coagulase-negative and coagulase-positive avian Staphylococcus spp. The size and copy numbers of the ermA gene were different from its human counterpart.
Nawaz
M S
MS
Division of Microbiology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, Arkansas 72079, USA. MNAWAZ@NCTR.FDA.GOV
Khan
A A
AA
Khan
S A
SA
Paine
D D
DD
Pothuluri
J V
JV
Cerniglia
C E
CE
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002645:Chickens / Q000235:genetics* / Q000382:microbiology; D004269:DNA, Bacterial / Q000235:genetics*; D004352:Drug Resistance, Microbial; D004917:Erythromycin / Q000494:pharmacology*; D008969:Molecular Sequence Data; D011201:Poultry Diseases / Q000235:genetics / Q000382:microbiology*; D013203:Staphylococcal Infections / Q000235:genetics*; D013210:Staphylococcus / Q000472:pathogenicity
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004917:Erythromycin