Marcelle Aquino Rabelo

Prevalence and risk factors for Staphylococcus aureus in health care workers at a University Hospital of Recife-PE

Staphylococcus aureus is the main human pathogen that colonizes individuals in general population. The objective of the study was evaluate the epidemiological and sensitivity profile of S. aureus lineage, isolated in health care workers (HCW) of a University Hospital in Pernambuco state, Brazil. Biological samples of hands and nasal cavities were sown in agar sheep blood. Colonies under suspicion of being S. aureus were identified using Gram staining, catalase test and coagulase, mannitol-salty agar fermentation and DNAse agar. The resistance to mupirocin was analyzed through the Kirby Bauer technique. In relation to methicillin and vancomycin the determination was by the minimum inhibitory concentration method (E-test). From the 202 HCW evaluated, 52 were colonized by S. aureus (25,7%). The factors associated to the colonization by S. aureus were: age-group, professional category, use of individual protection equipments (frequency and numbers). All S. aureus isolate lineages were sensitive to mupirocin and vancomycin, and three of them were identified as methicillin-resistant. The prevalence of MSSA and MRSA among HCW was considered low and was below the results described in the literature. The isolate S. aureus lineages have shown low resistance profile.

Colonização pelo Staphylococcus aureus em profissionais de enfermagem de um hospital escola de Pernambuco

Estudio realizado para identificar prevalencia de colonizacion por Staphylococcus aureus en profesionales de enfermeria de hospital universitario de Pernambuco, asi como evaluar el perfil de resistencia de la bacteria aislada. Se realizo un estudio transversal en el que se recolectaron muestras biologicas de manos y cavidad nasal. La identificacion del S. aureus se realizo mediante cultivo en agar-sangre, agar-manitol salado y mediante pruebas de catalasa y coagulasa. El perfil de sensibilidad se determino por tecnica de Kirby Bauer y para la determinacion de resistencia a meticilina se realizo screening en placa con oxalacina, con adicion de 4% de NaCl. De 150 profesionales evaluados, 39 estaban colonizados, lo que demostro prevalencia de 25,8%. Entre las variables estudiadas, faja etaria y cantidad de EPI se presentaron asociadas con la colonizacion por la bacteria. De todas las cepas aisladas, apenas cinco presentaron resistencia a meticilina.This study was performed with the objective to identify the prevalence of colonization by Staphylococcus aureus in nursing professionals from a teaching hospital in Pernambuco, and evaluate the resistance profile of these isolates. To do this, we performed a cross-sectional study where biological samples were collected from the hands and nasal cavities of the subjects. S. aureus was identified using agar (blood agar and mannitol salt) via catalase and coagulase tests. The sensitivity profile was determined by Kirby Bauer technique and determination of methicillin resistance was performed with oxacillin screening with sodium chloride (NaCl) addition. Of the 151 professionals evaluated, 39 were colonized which showed a prevalence of 25.8%. Among the variables studied, age and use of PPE were associated with colonization by the organism. Of all the isolates, only five were resistant to methicillin.

Colonization by Staphylococcus aureus among the nursing staff of a teaching hospital in Pernambuco

Estudio realizado para identificar prevalencia de colonizacion por Staphylococcus aureus en profesionales de enfermeria de hospital universitario de Pernambuco, asi como evaluar el perfil de resistencia de la bacteria aislada. Se realizo un estudio transversal en el que se recolectaron muestras biologicas de manos y cavidad nasal. La identificacion del S. aureus se realizo mediante cultivo en agar-sangre, agar-manitol salado y mediante pruebas de catalasa y coagulasa. El perfil de sensibilidad se determino por tecnica de Kirby Bauer y para la determinacion de resistencia a meticilina se realizo screening en placa con oxalacina, con adicion de 4% de NaCl. De 150 profesionales evaluados, 39 estaban colonizados, lo que demostro prevalencia de 25,8%. Entre las variables estudiadas, faja etaria y cantidad de EPI se presentaron asociadas con la colonizacion por la bacteria. De todas las cepas aisladas, apenas cinco presentaron resistencia a meticilina.This study was performed with the objective to identify the prevalence of colonization by Staphylococcus aureus in nursing professionals from a teaching hospital in Pernambuco, and evaluate the resistance profile of these isolates. To do this, we performed a cross-sectional study where biological samples were collected from the hands and nasal cavities of the subjects. S. aureus was identified using agar (blood agar and mannitol salt) via catalase and coagulase tests. The sensitivity profile was determined by Kirby Bauer technique and determination of methicillin resistance was performed with oxacillin screening with sodium chloride (NaCl) addition. Of the 151 professionals evaluated, 39 were colonized which showed a prevalence of 25.8%. Among the variables studied, age and use of PPE were associated with colonization by the organism. Of all the isolates, only five were resistant to methicillin.

The occurrence and dissemination of methicillin and vancomycin-resistant Staphylococcus in samples from patients and health professionals of a university hospital in Recife, State of Pernambuco, Brazil

INTRODUCTION Methicillin-resistant Staphylococcus aureus (MRSA) strains have been responsible for many nosocomial outbreaks. Within hospitals, colonized employees often act as reservoirs for the spread of this organism. This study collected clinical samples of 91 patients admitted to the intensive care unit (ICU), hemodialysis/nephrology service and surgical clinic, and biological samples from the nasal cavities of 120 professionals working in those environments, of a University Hospital in Recife, in the State of Pernambuco, Brazil. The main objective of this study was to determine the occurrence and dissemination of methicillin- and vancomycin-resistant Staphylococcus spp. METHODS The isolates obtained were tested for susceptibility to oxacillin and vancomycin and detection of the mecA gene. In addition, the isolates were evaluated for the presence of clones by ribotyping-polymerase chain reaction (PCR). RESULTS MRSA occurrence, as detected by the presence of the mecA gene, was more prevalent among nursing technicians; 48.1% (13/27) and 40.7% (11/27) of the isolates were from health professionals of the surgical clinic. In patients, the most frequent occurrence of mecA-positive isolates was among the samples from catheter tips (33.3%; 3/9), obtained mostly from the hemodialysis/nephrology service. Eight vancomycin-resistant strains were found among the MRSA isolates through vancomycin screening. Based on the amplification patterns, 17 ribotypes were identified, with some distributed between patients and professionals. CONCLUSIONS Despite the great diversity of clones, which makes it difficult to trace the source of the infection, knowledge of the molecular and phenotypic profiles of Staphylococcus samples can contribute towards guiding therapeutic approaches in the treatment and control of nosocomial infections.

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

INTRODUCTION There is a mechanism of macrolide resistance in Staphylococcus spp. which also affects the lincosamides and type B streptogramins characterizing the so-called MLSB resistance, whose expression can be constitutive (cMLSB) or inducible (iMLSB) and is encoded mainly by ermA and ermC genes. The cMLSB resistance is easily detected by susceptibility testing used in the laboratory routine, but iMLSB resistance is not. Therapy with clindamycin in cases of infection with isolated iMLSB resistance may fail. OBJECTIVE To characterize the phenotypic (occurrence of cMLSB and iMLSB phenotypes) and molecular (occurrence of ermA and ermC genes) profiles of MLSB 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 iMLSB phenotype was detected by D test. Isolates with cMLSB and iMLSB phenotypes were subjected to polymerase chain reaction (PCR) for the detection of ermA and ermC genes. RESULTS The cMLSB and iMLSB phenotypes were respectively identified in 39 (37.9%) and five (4.9%) isolates. The iMLSB 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 iMLSB phenotype had been less frequent than the cMLSB. It was important to perform the D test for its detection to guide therapeutic approaches.

Antimicrobial resistance profile of Staphylococcus aureus isolates obtained from skin and soft tissue infections of outpatients from a university hospital in Recife -PE, Brazil

BACKGROUND Staphylococcus aureus has a notable ability to acquire resistance to antibiotics, and methicillin resistance represents a growing public health problem. Methicillin-resistant S. aureus (MRSA) has also become important outside the hospital environment, particularly in the United States. In Brazil, since 2005, cases of community skin infections caused by MRSA have been reported, but resistance studies involving outpatients are scarce. OBJECTIVE To know the resistance profile of S. aureus involved in skin and soft tissue infections of patients seen at the Dermatology outpatient clinic of a university hospital in Recife, Pernambuco State, northeastern Brazil. METHODS Prospective study involving 30 patients with skin and soft tissue infections, seen at the Dermatology outpatient clinic from May until November 2011. To evaluate the susceptibility of S. aureus to antibiotics, the disk diffusion method and oxacillin screening agar were used. RESULTS From a total of 30 samples of skin lesions, 19 (63%) had positive culture for S. aureus. The following resistance patterns of S. aureus were observed: penicillin, 95%; tetracycline, 32%; erythromycin, 21%; gentamicin, 16%; cefoxitin, 11%; oxacillin, 11%; trimethoprim-sulfamethoxazole, 11%; chloramphenicol, 11%; clindamycin, 5% ; and ciprofloxacin, 0%. One of the identified MRSA was obtained from a patient without risk factors for its acquisition, and was resistant, beyond to the beta-lactams, only to tetracycline. CONCLUSIONS With regard to the resistance patterns of S. aureus, resistances to tetracycline, erythromycin and gentamicin were the highest. It was documented, for the first time in Pernambuco, a case of skin infection caused by community-associated MRSA.

Phenotypic methods for determination of methicillin resistance in Staphylococcus spp. from health care workers

INTRODUCTION: Staphylococcus spp. is an important healthcare-associated pathogen and the identification of methicillin-resistant strains in samples of colonization may provide data to assist in the antimicrobial therapy success. OBJECTIVES: To determine the occurrence of colonization by methicillin-resistant Staphylococcus spp. (MRS), through the detection of the mecA gene and to evaluate different phenotypic methods for the presumptive detection of methicillin resistance in samples of the anterior nasal cavity and hands of the health care personnel of a university hospital in the state of Pernambuco, Brazil. METHODS: We selected the 28 isolates of Staphylococcus spp., which showed an intermediate or resistant phenotypic profile for oxacillin, detected by the Kirby Bauer technique. The methods used were disk-diffusion tests for cefoxitin, minimal inhibitory concentration by E-test for oxacillin, screening for oxacillin resistance and mecA gene detection by polymerase chain reaction (PCR). RESULTS: About the phenotypic methods utilized, only the E-test of oxacillin did not show a statistically significant difference in relation to PCR for the mecA gene detection, considered the gold standard. CONCLUSION: The E-test of oxacillin was the best of the phenotypic methods utilized. It is necessary to correctly detect MRS in healthy individuals, because they can act as carriers and can therefore be a potential source of microorganisms involved in hospital infections.

Occurrence of the vanA gene in Staphylococcus epidermidis from nasopharyngeal secretion of Health-Care Workers, Recife, Brazil

INTRODUCTION The increasing reports of vancomycin-resistant Staphylococcus strains (VRS) haves caused concern worldwide, from the laboratory detection to patient management. This study aimed to identify the occurrence of VRS strains among healthcare professionals from a university hospital. METHODS A total of 102 Staphylococcus sp. isolates from healthcare professionals, obtained in a previous study were evaluated according to standard techniques for VRS detection. RESULTS After screening inoculation of plates containing 6µg/ml of vancomycin, 19 resistant isolates were identified. The susceptibility profile to other antimicrobials revealed 18 multidrug resistant isolates. The minimum inhibitory concentration (MIC) was determined by E-test and broth microdilution. According to E-tests, of 19 isolates grown in BHI-V6, four isolates presented MIC ≥ 128 µg/ml, seven with MIC ranging from 4 to 8 µg/ml, and eight with MIC ≤ 2µg/ml. By broth microdilution, 14 isolates presented MIC ≤ 2 µg/ml and five with MIC ≥ 16µg/ml. The presence of the gene vanA was determined by PCR in the five resistant isolates, and this gene was detected in one of the strains. Furthermore, among the 19 strains, the gene mecA was found in 13 (39,4%) isolates, including the strain carrying the gene vanA. CONCLUSIONS Based on these results, we highlight the presence of one strain carrying both vanA and the mecA genes, as well as multidrug-resistant strains colonizing healthcare professionals, and their importance as potential vectors to spread strains carrying resistance genes in the hospital environment.

Colonización por Staphylococcus aureus en profesionales de enfermería de un hospital escuela de Pernambuco

Estudio realizado para identificar prevalencia de colonizacion por Staphylococcus aureus en profesionales de enfermeria de hospital universitario de Pernambuco, asi como evaluar el perfil de resistencia de la bacteria aislada. Se realizo un estudio transversal en el que se recolectaron muestras biologicas de manos y cavidad nasal. La identificacion del S. aureus se realizo mediante cultivo en agar-sangre, agar-manitol salado y mediante pruebas de catalasa y coagulasa. El perfil de sensibilidad se determino por tecnica de Kirby Bauer y para la determinacion de resistencia a meticilina se realizo screening en placa con oxalacina, con adicion de 4% de NaCl. De 150 profesionales evaluados, 39 estaban colonizados, lo que demostro prevalencia de 25,8%. Entre las variables estudiadas, faja etaria y cantidad de EPI se presentaron asociadas con la colonizacion por la bacteria. De todas las cepas aisladas, apenas cinco presentaron resistencia a meticilina.This study was performed with the objective to identify the prevalence of colonization by Staphylococcus aureus in nursing professionals from a teaching hospital in Pernambuco, and evaluate the resistance profile of these isolates. To do this, we performed a cross-sectional study where biological samples were collected from the hands and nasal cavities of the subjects. S. aureus was identified using agar (blood agar and mannitol salt) via catalase and coagulase tests. The sensitivity profile was determined by Kirby Bauer technique and determination of methicillin resistance was performed with oxacillin screening with sodium chloride (NaCl) addition. Of the 151 professionals evaluated, 39 were colonized which showed a prevalence of 25.8%. Among the variables studied, age and use of PPE were associated with colonization by the organism. Of all the isolates, only five were resistant to methicillin.