Silvana Oliveira dos Santos

Evaluation of constitutive and inducible resistance to clindamycin in clinical samples of Staphylococcus aureus from a tertiary hospital

INTRODUCTION Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) have become common in hospitals and the community environment, and this wide resistance has limited patient treatment. Clindamycin (CL) represents an important alternative therapy for infections caused by S. aureus. Antimicrobial susceptibility testing using standard methods may not detect inducible CL resistance. This study was performed to detect the phenotypes of resistance to macrolides-lincosamides-streptogramin B (MLSB) antibiotics, including CL, in clinical samples of S. aureus from patients at a tertiary hospital in Santa Maria, State of Rio Grande do Sul, Brazil. METHODS One hundred and forty clinical isolates were submitted to the disk diffusion induction test (D-test) with an erythromycin (ER) disk positioned at a distance of 20mm from a CL disk. The results were interpreted according to the recommendations of the Clinical and Laboratory Standards Institute (CLSI). RESULTS In this study, 29 (20.7%) of the 140 S. aureus samples were resistant to methicillin (MRSA), and 111 (79.3%) were susceptible to methicillin (MSSA). The constitutive resistance phenotype (cMLSB) was observed in 20 (14.3%) MRSA samples and in 5 (3.6%) MSSA samples, whereas the inducible resistance phenotype (iMLSB) was observed in 3 (2.1%) MRSA samples and in 8 (5.8%) MSSA samples. CONCLUSIONS The D-test is essential for detecting the iMLSB phenotype because the early identification of this phenotype allows clinicians to choose an appropriate treatment for patients. Furthermore, this test is simple, easy to perform and inexpensive.

PREVALÊNCIA E PERFIL DE SENSIBILIDADE DE Staphylococcus aureus ISOLADOS EM UM HOSPITAL ESCOLA NA CIDADE DE SANTA MARIA, BRASIL

Objetivou-se caracterizar a prevalencia e o perfil de suscetibilidade de Staphylococcus aureus isolados no Hospital Universitario de Santa Maria (HUSM), atraves de levantamento de dados junto ao Laboratorio de Analises Clinicas, durante o periodo de abril a junho de 2009. Foram solicitadas 3270 culturas, sendo que 1123 (34%) resultaram positivas. A prevalencia de S. aureus em relacao as culturas positivas foi de 89 (7,93%). Verificou-se que 33% das cepas foram resistentes a oxacilina e que 34,45% apresentaram resistencia relacionada ao gene erm. Elevada sensibilidade ao sulfametoxazol-trimetoprima (72/80%) foi evidenciada pela automacao e nenhuma cepa mostrou-se resistente a vancomicina. Portanto, a prevalencia de S. aureus no HUSM e a resistencia a oxacilina foram inferiores ao observado em outros hospitais terciarios brasileiros. The objective ofthis study was to characterize the prevalence and susceptibility prof ile ofStaphylococcus aureus isolates at University Hospital ofSantaMaria, through data collection at the Laboratory ofClinicalAnalysis, duringApril to June 2009. Were requested 3270 cultures and 1123 (34%) were positive. The prevalence of S. aureus in relation to positive cultures was 89 (7,93%). It was f ound that these strains, 33% were resistant to oxacillin and 34.45% showed resistance related erm gene. High sensitivity to trimethoprim-sulf amethoxazole (72/80%) was detected f or the automation and no strain showed resistance to vancomycin. Theref ore, the prevalence of S. aureus and oxacillin resistance at HUSM were lower than observed in other tertiary hospitals in Brazil. Descritors: Prevalence; Staphylococcus aureus; Bacterial inf ection, Oxacillin.

Colistin resistance in non-fermenting Gram-negative bacilli in a university hospital

Indiscriminate use of antimicrobials has caused the worldwide emergence of multidrug resistant bacteria (MDR). Glucose non-fermenting Gram-negative bacilli (NF-GNB) that show resistance to several antimicrobials, including colistin, have been reported. The highest rates of this type of resistance have been registered in Asia and Europe.1 This fact has created problems in therapy, since the colistin is used as last alternative to treat infections caused by MDR bacteria.2 Pseudomonas aeruginosa is a skilful microorganism that causes severe opportunistic infections in immunocompromised patients due to its metabolic versatility.3 Isolation of P. aeruginosa resistant to almost all available antimicrobials is increasing in Intensive Care Units (ICU), leading to an increase in the number of healthcare-associated infections (HAI), significantly influencing morbidity, mortality, and high costs of treatment of infected patients.1 In a prospective study developed between August 2015 and January 2016 we isolated 293 NF-GNB of various clinical specimens from patients admitted to a university hospital in the central region of Rio Grande do Sul, Brazil. Identification and antimicrobials sensitivity test were performed through the automated system VITEK®2 (bioMérieux). Data were interpreted according to the document M100-S25 of the Clinical and Laboratory Standards Institute [CLSI, 2015], considering resistant the isolated specimens which showed intermediate or resistant colistin profiles. From the 293 NF-GNB assessed in this study, only two genera were identified: 78.83% (231) P. aeruginosa and 21.16% (62) Acinetobacter spp. Colistin resistance was identified in nine isolated strains of P. aeruginosa (9/231-3,89%) and none in Acinetobacter spp. The predominant age group of patients in whom colistin-resistant strains were identified was 41–69 years old (77.77%); this age-range also showed expressive resistance to carbapenems (66.67%) (Table 1). Colistin-resistant P. aeruginosa were predominantly isolated from clinical specimens obtained from soft tissues (3/9-33.33%) and respiratory (sputum and tracheal secretion – 2/9-22.22%) secretions. The hospital wards in which resistant strains were initially identified were internal medicine Table 1 – Sensitivity profile of 9 P. aeruginosa isolates resistant to colistin.

Phenotypic methods for screening carbapenem-resistant Enterobacteriaceae and assessment of their antimicrobial susceptibility profile

INTRODUCTION: In this study, we used phenotypic methods to screen carbapenem-resistant Enterobacteriaceae (CREs) and evaluated their antimicrobial sensitivity profile. METHODS: One hundred and seventy-eight CREs were isolated at a university hospital in south Brazil in a one-year period. Samples were assessed using disk diffusion tests with inhibitors of β-lactamases such as phenylboronic acid (AFB), cloxacillin (CLOXA), and ethylenediaminetetraacetic acid (EDTA). Strains with differences in zone diameters ≥ 5mm for disks supplemented or not were considered producers of carbapenemases. RESULTS: Klebsiella pneumoniae was the most prevalent CRE, which appeared in 80.3% cases (n = 143). Among clinical materials, the rectal swab was responsible for 43.4% of the isolations (n = 62), followed by urine (18.9%; n = 27). Among the CREs identified in this study, the growth of 56.7% (n = 101) isolates, which were putative producers of Klebsiella pneumoniae carbapenemase (KPC), were inhibited by AFB, whereas 7.3% (n = 13) isolates were inhibited by both AFB and CLOXA and were considered as putative producers of plasmid-mediated AmpC; approximately 3.4% (n = 6) were inhibited by EDTA, which possibly produced metallo-β-lactamase. Lastly, 32.6% (n = 58) cases showed negative results for AFB, CLOXA, and EDTA sensitivity, and represented another class of β-lactamases and/or mechanism of resistance. CONCLUSIONS: Phenotypic screening of CREs is important for clinical laboratories that monitor outbreaks of resistant microbes. Phenotypic tests that use carbapenemase inhibitors and enhancers such as AFB, CLOXA, and EDTA are necessary since they are good screening methods for the detection of carbapenemases.

Staphylococcal scalded skin syndrome in a premature newborn caused by methicillin-resistant Staphylococcus aureus: case report

CONTEXT Staphylococcal scalded skin syndrome is an exfoliative skin disease. Reports of this syndrome in newborns caused by methicillin-resistant Staphylococcus aureus are rare but, when present, rapid diagnosis and treatment is required in order to decrease morbidity and mortality. CASE REPORT A premature newly born girl weighing 1,520 g, born with a gestational age of 29 weeks and 4 days, developed staphylococcal scalded skin syndrome on the fifth day of life. Cultures on blood samples collected on the first and fourth days were negative, but Pseudomonas aeruginosa and Enterococcus sp. (vancomycin-sensitive) developed in blood cultures performed on the day of death (seventh day), and Pseudomonas aeruginosa and Serratia marcescens were identified in cultures on nasopharyngeal, buttock and abdominal secretions. In addition to these two Gram-negative bacilli, methicillin-resistant Staphylococcus aureus was isolated in a culture on the umbilical stump (seventh day). The diagnosis of staphylococcal scalded skin syndrome was based on clinical criteria.

Prevalence of methicillin-resistant Staphylococcus aureus in a University Hospital in the South of Brazil

Methicillin-resistant Staphylococcus aureus (MRSA) stand out as one of the main agents causing nosocomial and community infections. This retrospective study aimed to analyze the MRSA predominance in a university hospital in the south of Brazil and it was carried out for five years (from 2007 to 2011). 616 MRSA (33,3% of the total) were isolated and an important reduction in the MRSA predominance was observed along the study. Although it was registered a reduction in the MRSA predominance, male adult patients (41-70 years old), who were in the Medical Clinic and Adult ICU, had the highest infection rates and concerning MRSA isolates rates, these were higher in blood and tracheal aspirates. In conclusion, studies of this type are becoming relevant to recognize pathogens like MRSA and to determine its predominance.

Carbapenem-resistant Acinetobacter spp. and Pseudomonas aeruginosa at the University Hospital of Santa Maria, Rio Grande do Sul state, Brazil

AIMS: To evaluate the characteristics of antimicrobial susceptibility of carbapenem-resistant Acinetobacter spp. and Pseudomonas aeruginosa isolated from August 2011 to January 2012 from inpatients at the University Hospital of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil. METHODS: A retrospective study was conducted by consulting the database of the Microbiology Laboratory, which included all isolates of Acinetobacter spp. and P. aeruginosa from different clinical specimens collected from hospitalized patients who had resistant or intermediate profile to carbapenemic antimicrobials used in this hospital (imipenem, meropenem and ertapenem) verified through conventional methodology by disc diffusion (Kirby-Bauer) or automated method (MicroScan ® - Siemens) according to the standards recommended by the Clinical and Laboratory Standards Institute. RESULTS: In the studied period 58 samples of nonfermenters Gram-negative bacilli resistant to carbapenems were found, 32 of the genus Acinetobacter and 26 of P. aeruginosa. Acinetobacter spp. was more isolated in the intensive care unit, while P. aeruginosa prevailed in the emergency and outpatient departments. Both microorganisms came mainly from respiratory secretions. CONCLUSIONS: In this study, Acinetobacter spp. and P. aeruginosa showed high antimicrobial resistance. Polymyxin B was a good antimicrobial for the treatment of infections caused by microorganisms resistant to carbapenems in this hospital.

CARACTERIZAÇÃO DE CULTURAS DE URINA REALIZADAS NO LABORATÓRIO DE ANÁLISES CLÍNICAS DO HOSPITAL UNIVERSITÁRIO DE SANTA MARIA – SANTA MARIA, RS, NO PERÍODO DE 2007 À 2010

A infeccao do trato urinario (ITU) e considerada uma das doencas mais comuns de origem bacteriana. Objetivou-se determinar a prevalencia de ITU em pacientes atendidos no Hospital Universitario de Santa Maria, o agente mais isolado, a incidencia entre os sexos e a faixa etaria mais acometida. Realizou-se um estudo retrospectivo das uroculturas solicitadas no HUSM, no periodo de 2007 a 2010, as quais foram cultivadas no setor de Microbiologia do Laboratorio de Analises Clinicas. Dos 34.898 exames solicitados, 6.190 (17,74%) foram positivos. O sexo feminino apresentou o maior percentual de positividade (72,94%) e a faixa etaria feminina mais acometida foi entre 14 a 40 anos (37,6%) e a masculina entre 41 a 64 anos (10,6%). O microrganismo prevalente foi a Escherichia coli com 31,9%. A partir deste estudo pode-se verificar que os bacilos gram-negativos (BGN) foram os patogenos prevalentes, alem disso, ocorreu um significativo numero de isolados de Candida sp.

ABORDAGEM DAS DOENÇAS SEXUALMENTE TRANSMISSÍVEIS NA ADOLESCÊNCIA: REVISÃO DE LITERATURA

O estudo objetivou reportar sobre os riscos de contagio das Doencas Sexualmente Transmissiveis (DSTs), apresentando as principais formas de transmissao, sinais e sintomas associados, tratamento e prevencao. Realizou-se uma revisao bibliografica no periodo de abril a junho de 2015, por meio das bases de dados (SciELO, PubMed, LILACS e BIREME), cartilhas e materiais do Ministerio da Saude, publicados entre 2003 a 2015 envolvendo os descritores: “doencas sexualmente transmissiveis”, “adolescente”, “sexualidade” e “vulnerabilidade em saude” no idioma ingles e portugues. A busca resultou em 63 publicacoes das quais 58 foram selecionadas a partir da leitura dos resumos dos materiais para elaboracao deste trabalho por abordarem o tema proposto. Pode se observar que a disseminacao das DSTs entre a populacao jovem e crescente, sendo necessario investir continuamente em acoes de carater educativo que visem a reducao dos fatores de riscos e possam contribuir para sua cidadania. Descritores: Doencas Sexualmente Transmissiveis; Adolescente; Sexualidade; Vulnerabilidade em Saude.