Induced and Constitutive Clindamycin Resistance in Staphylococcus spp. Strains Isolated from a Neonatal Intensive Care Unit

Aims: The hospital environment can act as a reservoir for microorganisms, which in turn can contaminate a range of hospital equipment and survive for long periods of time. One of these environments the Neonatal Intensive Care Unit (NICU), for the initial post partum period serving as a home for newborns of low birth weight and needing invasive procedures for administration of nutritional and medicinal substances, which makes the NICU a critical area for housing individuals with immune system. Thus, the aim of this study was to evaluate the phenotypic appearance of resistance of the Staphylococcus spp. compared to erythromycin and clindamycin, originating from isolated areas of a NICU in the city of Campina Grande - PB.
Place and Duration of Study: Sample: Neonatal Intensive Care Unit of a public hospital in the city of Campina Grande – PB, Brazil. Processing and Analysis of Samples: Clinical Analysis Laboratory of the State University of Paraíba, between August and October 2012.
Methodology: Samples were collected from surfaces present at the NICU. The samples were identified and strains of Staphylococcus spp. were subjected to sensitivity, and to verify erythromycin-induced resistance the D-test was used, following the CLSI standards-M100-S22 (2012).
Results: Bacterial strains from all surfaces analyzed were isolated, 59.02% of isolates belong to the genus Staphylococcus spp., representing 36 bacterial strains, of which 31 were subspecies Staphylococcus aureus and 5 were coagulase-negative staphylococcus (CoNS). There was found more than 70% resistance to the group of penicillins and more than 30% to methicillin. Among the 36 strains of Staphylococcus spp. 19.45% were resistant to erythromycin. The rate found for constitutive resistance to macrolides (MLSBc) was 5.56% and was observed induced resistance to the macrolide type (MLSBi) in 2.78% the strains.
Conclusion: The resistotyping of isolated strains for inducible and constitutive resistance may be considered a test of substantial importance not only as an epidemiologic marker in view of analyzing possible dissemination of hospital strains, but with respect to adequate, and precise determination of the antibiotic treatment of neonates.