Phenotypic and molecular characterization of resistance to macrolides, lincosamides and type B streptogramin of clinical isolates of Staphylococcus spp. of a university hospital in Recife, Pernambuco, Brazil

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• 作者：Jussyê ; gles Niedja da Paz Pereira ; ^{ju-biomed@hotmail.com" class="auth_mail" title="E-mail the corresponding author} ; Marcelle Aquino Rabelo ; Jailton Lobo da Costa Lima ; Armando Monteiro Bezerra Neto ; Ana Catarina de Souza Lopes ; Maria Amé ; lia Vieira Maciel
• 关键词：Staphylococcus ; Clindamycin ; Inducible resistance ; erm genes
• 刊名：The Brazilian Journal of Infectious Diseases
• 出版年：2016
• 出版时间：May-June 2016
• 年：2016
• 卷：20
• 期：3
• 页码：276-281
• 全文大小：720 K

文摘

There is a mechanism of macrolide resistance in Staphylococcus spp. which also affects the lincosamides and type B streptogramins characterizing the so-called MLS_B resistance, whose expression can be constitutive (cMLS_B) or inducible (iMLS_B) and is encoded mainly by ermA and ermC genes. The cMLS_B resistance is easily detected by susceptibility testing used in the laboratory routine, but iMLS_B resistance is not. Therapy with clindamycin in cases of infection with isolated iMLS_B resistance may fail.

Objective

To characterize the phenotypic (occurrence of cMLS_B and iMLS_B phenotypes) and molecular (occurrence of ermA and ermC genes) profiles of MLS_B resistance of clinical isolates of susceptible and methicillin-resistant Staphylococcus aureus and CNS (coagulase-negative Staphylococcus) from patients of a university hospital, in Pernambuco.

Methods

The antimicrobial susceptibility of 103 isolates was determined by the disk diffusion technique in Mueller–Hinton agar followed by oxacillin screening. The iMLS_B phenotype was detected by D test. Isolates with cMLS_B and iMLS_B phenotypes were subjected to polymerase chain reaction (PCR) for the detection of ermA and ermC genes.

Results

The cMLS_B and iMLS_B phenotypes were respectively identified in 39 (37.9%) and five (4.9%) isolates. The iMLS_B phenotype was found only in four (10.8%) methicillin-susceptible S. aureus and one (4.5%) methicillin-resistant S. aureus. In the 44 isolates subjected to PCR, four (9.1%) only ermA gene was detected, a lower frequency when compared to only ermC 17 (38.6%) gene and to one (2.3%) isolate presenting both genes.

Conclusion

In the Staphylococcus spp. analyzed, the ermC gene was found more often than the ermA, although the iMLS_B phenotype had been less frequent than the cMLS_B. It was important to perform the D test for its detection to guide therapeutic approaches.