Fatal sepsis caused by mecA-positive oxacillin-susceptible Staphylococcus aureus: First report in a tertiary hospital of southern Brazil.

mecA-positive oxacillin phenotypically susceptible Staphylococcus aureus (OS-MRSA) is increasingly reported worldwide. This bacterium poses a therapeutic threat, as it can be misidentified as an oxacillin-susceptible organism by phenotypic methods that are routinely used in the majority of clinical microbiology laboratories. Herein, we report the first case of fatal sepsis in a 43-year-old female patient caused by an OS-MRSA SCCmec type IVa/ST1/CC1 in a tertiary hospital in southern Brazil, which highlights the difficulties involved in diagnosing this bacterium. Blood cultures and phenotypic susceptibility tests on admission yielded a penicillin-resistant S. aureus. Although vancomycin therapy was initiated, this antibacterial was replaced by oxacillin, based on the susceptibility result. However, the clinical conditions of the patient deteriorated rapidly evolving to fatal septic shock. Clinical microbiology laboratories should consider the use of additional tests to accurately distinguish between various antimicrobial phenotypes of S. aureus.

Development of a melting-curve based multiplex real-time PCR assay for simultaneous detection of Streptococcus agalactiae and genes encoding resistance to macrolides and lincosamides.

BACKGROUND: Streptococcus agalactiae or Group B Streptococcus (GBS) remains the leading cause of infections in newborns worldwilde. Prenatal GBS screening of pregnant women for vaginal-rectal colonization is recommended in many countries to manage appropriate intrapartum antimicrobial prophylaxis for those identified as carriers. In this study, a novel melting-curve based multiplex real-time PCR assay for the simultaneous detection of GBS and macrolide and lincosamide resistance markers was developed. The usefulness of the assay was evaluated for rapid and accurate prenatal GBS screening. METHODS: One hundred two pregnant women who were at 35-37 weeks of gestation were enrolled in this study. The analytical performance of the multiplex real-time PCR was first tested using a panel of reference and clinical bacterial and fungal strains. To test the clinical performance, vaginal-rectal swabs were obtained from pregnant women who were seen at the teaching hospital for regular prenatal care. The results of real-time were compared with those obtained from microbiological analyses. RESULTS: The real-time PCR assay showed 100% specificity and a limit of detection of 104 colony forming units equivalent per reaction. The prevalence of GBS colonization among the population studied was 15.7% (16/102) based on a positive culture and the real-time PCR results. Agreement between the two assays was found for 11 (68.75%) GBS colonized women. Using the culture-based results as a reference, the multiplex real-time PCR had a sensitivity of 91.7% (11/12, CI 59.7-99.6%), a specificity of 95.5% (86/90, CI 89.8-98.7%), a positive predictive value of 73.3% (11/15, CI 44.8-91.1%) and a negative predictive value of 98.9% (86/87, CI 92.9-99.9%). CONCLUSION: The multiplex real-time PCR is a rapid, affordable and sensitive assay for direct detection of GBS in vaginal-rectal swabs.

Phenotypic and genotypic characteristics of mecA - positive oxacillin-sensitive Staphylococcus aureus isolated from patients with bloodstream infection in a tertiary hospital in Southern Brazil.

Staphylococcus aureus are extremely important microorganisms, either from an epidemiological point of view or as a pathogen, responsible for causing a series of infectious processes, whether simple, restricted to the skin, or invasive infections such as bacteremia. The emergence of Oxacillin Sensitive-Methicillin Resistant S.aureus (OS-MRSA) isolates has imposed difficulties in the treatment of patients with staphylococcal infection, as such isolates can be mistakenly classified as sensitive and lead to failure of the therapy used. Thus, the objective of this study is to evaluate the prevalence, and genotypic and phenotypic characteristics, of OS-MRSA isolates, from bloodstream infections, collected from patients admitted to a hospital in southern Brazil, as well as to evaluate the treatment used. For this, 801 unique isolates of S. aureus, collected from blood cultures, between January 2011 and December 2020 were evaluated. Of these, 96 isolates were classified as sensitive to oxacillin. The isolates were identified and had their sensitivity profile performed by manual and automated methods. The minimum inhibitory concentration for vancomycin, daptomycin, oxacillin, linezolid and teicoplanine was performed by e-test. The mecA, vanA genes, typing of the SCCmec elements, as well as the search for the icaA, tst-1 and pvl virulence genes were performed by PCR. Biofilm formation was performed using the crystal violet technique. The Sequence Type (ST), as well as the Clonal Complex (CC) of the isolates was evaluated by the RTq -PCR. The clinical characteristics of the patients were evaluated through an active search in medical records. After investigating the mecA gene, 27.1% (26/96) of the isolates were considered OS-MRSA, with SCCmec type I being the most prevalent, 46.1% (12/26). Among the evaluated isolates, 41% (9/22) were included in CC5 and ST9. As for virulence, all isolates were positive for the icaA gene and characterized as strong biofilm formers. The pvl gene was found in 92.3% (24/26) of the isolates and the toxic shock syndrome toxin was present in 61.5% of the isolates (16/26). All isolates were negative for the presence of the van A gene. As for the clinical outcome, 73% (19/26) of the patients were discharged from the hospital and 27% (7/26) died. It was possible to observe a high frequency of OS-MRSA isolates causing bloodstream infections. Furthermore, such isolates contain several virulence genes, which may contribute to a worse clinical outcome.

Commensal Streptococcus agalactiae isolated from patients seen at University Hospital of Londrina, Paraná, Brazil: capsular types, genotyping, antimicrobial susceptibility and virulence determinants.

BACKGROUND: Streptococcus agalactiae or Group B Streptococci (GBS) have the ability to access various host sites, which reflects its adaptability to different environments during the course of infection. This adaptation is due to the expression of virulence factors that are involved with survival, invasion and bacterial persistence in the host. This study aimed to characterize GBS isolates from women of reproductive age seen at University Hospital of Londrina, according to capsular typing, genetic relatedness, antimicrobial susceptibility profile and occurrence of virulence determinants. RESULTS: A total of 83 GBS isolates were enrolled in this study. Capsular types Ia (42.2%), II (10.8%), III (14.5%) and V (30.1%) were identified in most GBS. One isolate each was classified as type IX and non-typeable.A total of 15 multiple locus variable number of tandem repeat analysis (MLVA) types were identified among the isolates, seven were singletons and eight were represented by more than four isolates. All isolates were susceptible to penicillin, ampicillin, cefepime, cefotaxime, chloramphenicol, levofloxacin and vancomycin. Resistance to erythromycin and clindamycin was observed in 19.3 and 13.3% of isolates, respectively. All isolates resistant to clindamycin were simultaneously resistant to erythromycin and were distributed in the capsular types III and V. One isolate showed the constitutive macrolide-lincosamide-streptogramin B (cMLS(B)) phenotype and ten showed the inducible MLS(B) (iMLS(B)) phenotype. The mechanism of resistance to erythromycin and clindamycin more prevalent among these isolates was mediated by the gene ermA, alone or in combination with the gene ermB. The isolates displaying resistance only to erythromycin belonged to capsular type Ia, and showed the M phenotype, which was mediated by the mefA/E gene. All isolates harbored the gene hylB and at least one pilus variant, PI-1, PI-2a or PI-2b. Although cylE was observed in all GBS, four isolates were classified as gamma-hemolytic and carotenoid pigment non-producers. CONCLUSIONS: Our results indicate the potential virulence of commensal GBS isolates, reinforcing the need for continued screening for this bacterium to prevent infections. The distribution of capsular and pili antigens, and MLVA profiles was also identified, which may contribute to the development of new strategies for the prevention and treatment of GBS infection.

High Prevalence of Panton-valentine Leukocidin-encoding Genes in Methicillin-resistant Staphylococcus aureus Isolated from Inpatients with Invasive Infections at a University Hospital in Southern Brazil.

BACKGROUND: Staphylococcus aureus is a major cause of a wide diversity of infections in humans, and the expression of Panton-Valentine Leukocidin (PVL) has been associated with severe clinical syndromes. OBJECTIVES: The present study aimed to investigate the prevalence of PVL-encoding genes in S. aureus isolated from clinical samples of inpatients with invasive infections in a teaching hospital in Southern Brazil. Furthermore, phenotypic and genotypic characteristics of bacterial isolates were analyzed. METHODS: A total of 98 S. aureus isolates recovered from different body sites were characterized according to their antimicrobial susceptibility profile, methicillin-resistance and SCCmec typing, genetic relatedness and occurrence of virulence-encoding genes, such as icaA, lukS-PV/lukF-PV, and tst. RESULTS: Sixty-eight (69.4%) isolates were classified as methicillin-resistant, and among them, four (5.9%) did not harbor the mecA gene. The mecA-harboring methicillin-resistant S. aureus (MRSA) isolates were grouped into SCCmec types I (6.3%), II (64.1%), III (6.3%), IV (15.6%), V (4.7%), and VI (1.6%). One isolate (1.6%) was classified as non-typeable (NT). Seventy isolates (71.4%) were classified as multidrug-resistant. The overall prevalence of virulence-encoding genes was as follows: icaA, 99.0%; tst, 27.5%; and lukS-PV/lukF-PV, 50.0%. The presence of tst gene was significantly higher (p < 0.001) in methicillin-susceptible S. aureus (MSSA) compared to MRSA isolates. CONCLUSION: The present study reports a high prevalence of multidrug-resistant S. aureus harboring lukS-PV/lukF-PV and tst genes in invasive infections. The continuous monitoring of the antimicrobial susceptibility profile and virulence of S. aureus is an important measure for the control of infections caused by this bacterium.

Development of a Melting-Curve-Based Multiplex Real-Time PCR Assay for the Simultaneous Detection of Viruses Causing Respiratory Infection.

The prompt and accurate identification of the etiological agents of viral respiratory infections is a critical measure in mitigating outbreaks. In this study, we developed and clinically evaluated a novel melting-curve-based multiplex real-time PCR (M-m-qPCR) assay targeting the RNA-dependent RNA polymerase (RdRp) and nucleocapsid phosphoprotein N of SARS-CoV-2, the Matrix protein 2 of the Influenza A virus, the RdRp domain of the L protein from the Human Respiratory Syncytial Virus, and the polyprotein from Rhinovirus B genes. The analytical performance of the M-m-qPCR underwent assessment using in silico analysis and a panel of reference and clinical strains, encompassing viral, bacterial, and fungal pathogens, exhibiting 100% specificity. Moreover, the assay showed a detection limit of 10 copies per reaction for all targeted pathogens using the positive controls. To validate its applicability, the assay was further tested in simulated nasal fluid spiked with the viruses mentioned above, followed by validation on nasopharyngeal swabs collected from 811 individuals. Among them, 13.4% (109/811) tested positive for SARS-CoV-2, and 1.1% (9/811) tested positive for Influenza A. Notably, these results showed 100% concordance with those obtained using a commercial kit. Therefore, the M-m-qPCR exhibits great potential for the routine screening of these respiratory viral pathogens.

Methicillin-Resistant Staphylococcus haemolyticus Displaying Reduced Susceptibility to Vancomycin and High Biofilm-Forming Ability.

BACKGROUND: Staphylococcus haemolyticus is one of the most frequently coagulasenegative staphylococci isolated from healthcare-associated infections, mainly those related to implanted medical devices. OBJECTIVES: This study aimed to determine the antimicrobial susceptibility profile and biofilm forming capacity of S. haemolyticus isolated from bloodstream infections. METHODS: A total of 40 S. haemolyticus isolates were characterized according to their genetic relatedness by repetitive element sequence based-PCR (REP-PCR), antimicrobial susceptibility profile, SCCmec typing, ability to form biofilm on abiotic surface and occurrence of putative genes related to biofilm formation. RESULTS: One S. haemolyticus was susceptible to all antimicrobials. The other isolates (n=39) were resistant to cefoxitin; and among them 34 (87.2%) harbored the mecA gene into the SCCmec type I (5.9%), type III (29.4%), type IV (5.9%) and type V (20.6%); and 38.2% isolates were designated as NT. Apart from cefoxitin, 94.9% of the isolates were resistant to at least four antimicrobial classes, and 32.5% displayed minimal inhibitory concentration (MIC) values higher than 4.0 µg/mL for vancomycin. All isolates formed biofilm on polystyrene surface and were classified as strong biofilm-producers, except for one isolate. All isolates were negative for icaA gene, and the prevalence of the other genes was as follows: atl, 100%; fbp, 92.5%; aap, 90.0%; and bap, 20.0%. CONCLUSION: This study reports a high prevalence of methicillin-resistant S. haemolyticus displaying decreased susceptibility to vancomycin with the ability to form strong biofilms on abiotic surface. The results support the importance of controlling the adequate use of antimicrobials for the treatment of staphylococcal infections.

Nasal Carriage by Staphylococcus aureus among Healthcare Workers and Students Attending a University Hospital in Southern Brazil: Prevalence, Phenotypic, and Molecular Characteristics.

BACKGROUND: Staphylococcus aureus can asymptomatically colonize the human anterior nares and skin, and nasal colonization by this bacterium represents a potential risk for development of invasive infections. The aim of this study was to determine the prevalence of S. aureus nasal carriage among healthcare workers and students attending a university hospital and to characterize the isolates phenotypically and molecularly. METHODS: A cross-sectional study was performed with 324 volunteers. Cultures from nasal samples were obtained and S. aureus isolates were characterized according to their antimicrobial susceptibility profile and four virulence factors-encoding genes. MRSA isolates were characterized regarding their oxacillin/cefoxitin susceptibility, SCCmec, and REP-PCR types. Potential risks for S. aureus and MRSA carriage were analyzed. RESULTS: Of 324 nasal samples, 42.9% were identified as S. aureus, of which 28.8% were MRSA. S. aureus carriers were significantly higher in males and students (OR = 2.898, 95%CI 1.553-5.410); however, no variables were associated with MRSA carriage. All isolates were susceptible to vancomycin and the highest rate of resistance was observed for penicillin (90.6%). All isolates harbored the coa gene, and 97.8%, the icaA gene; 15.8% and 6.5% were positive for tst and lukS-PV/lukF-PV genes, respectively. Among MRSA isolates, 45% carried the mecA gene but were phenotypically susceptible to oxacillin/cefoxitin; two harbored the tst and none had lukS-PV/lukF-PV genes. All MRSAs were distributed into six SCCmec types and type I (62.5%) was the most frequent. REP-PCR typing identified four main clusters among MRSA isolates. CONCLUSION: High prevalence of healthcare workers and students were identified as nasal carriers of S. aureus exhibiting different antimicrobial resistance profiles, including mecA-positive oxacillin-susceptible S. aureus (OS-MRSA) and the presence of virulence-encoding genes. Both cohorts may represent potential sources for the emergence of a successful S. aureus strain highly adapted to the hospital environment.

Colonization by multidrug-resistant microorganisms of hospitalized newborns and their mothers in the neonatal unit context.

INTRODUCTION: The mother plays a fundamental role in the constitution and regulation of her child's healthy microbiota, however, preterm newborns are separated from their mothers soon after birth and transferred to Neonatal Intensive Care Units, being exposed the constant risk for the development of multidrug-resistant microorganisms' infections. The aim of this study was to explore the multidrug-resistant microorganism colonization of hospitalized babies and their mothers in the neonatal unit context. METHODOLOGY: A prospective case study conducted with hospitalized babies and their mothers in the Neonatal Unit at a university hospital. The sample was composed of 433 binomials (mother-child). Colonization culture samples were taken at the moment of the baby's discharge, via two swabs in the oral, nasal, axillary, inguinal, and rectal regions. RESULTS: The colonization incidence among the binomials, 30 (6.9%) were both colonized by multi-resistant microorganisms. Mothers of colonized babies (24.4%) demonstrated a higher chance of colonization in comparison to mothers of non-colonized babies (11.9%) (p = 0.002). Relationships were drawn between baby colonization and prematurity, extremely low birth weight, and non-exclusive maternal breastfeeding (p<0.05). ESBL-producing Gram-negative microorganisms were more frequent in the cultures of the binomials, with 35.9% of the babies colonized with Klebsiella spp. ESBL and 42.0% of the mothers with Escherichia coli ESBL. Furthermore, 50% of the binomials were colonized with E. coli ESBL. CONCLUSION: The prematurity, extremely low birth weight, and non-exclusive breastfeeding at hospital discharge were associated with baby colonization by multidrug-resistant microorganism. Furthermore, mothers of colonized children presented higher chances of colonization.

Colonization profile and duration by multi-resistant organisms in a prospective cohort of newborns after hospital discharge.

The aim of this study was to determine the spontaneous decolonization period and characteristics in a prospective cohort of newborns colonized by multidrug-resistant organisms, after their discharge from the neonatal intensive care unit. Multidrug resistance is defined as bacterial non-susceptibility to ≥ 1 agent of ≥ 3 antimicrobial categories. In total, 618 newborns were included in the study, of which 173 (28.0%) presented a positive culture for multidrug-resistant microorganisms, and of these, 52 (30.1%) were followed up in this study. The most frequent intrinsic factors were be born by cesarean section (86.5%), prematurity (84.6%), and very low birth weight (76.9%). The extrinsic factors were having remained hospitalized for an average of 27 days, during which 67.3% were submitted to invasive procedures and 88.5% received antimicrobials. The intrinsic and extrinsic factors of newborns were not associated to a decolonization period longer or shorter than 3 months, which was the average period of decolonization found in the present study. From the totality of colonization cultures sampled at hospital discharge, the Gram-negative Extended Spectrum ß-lactamase producing bacteria were the most common, with 28.9% of babies colonized by Klebsiella spp. The median period of decolonization by multidrug-resistant microorganisms in the newborns population after hospital discharge was 3 months, but was highly dependent on the microbial species, and this period was not associated to any intrinsic and extrinsic factors of the newborn.

Escherichia coli Bloodstream Infections in Patients at a University Hospital: Virulence Factors and Clinical Characteristics.

Extraintestinal pathogenic Escherichia coli (ExPEC) isolates are responsible for many bloodstream infections. The aim of this study was to characterize E. coli isolated from the bloodstreams of patients (n = 48) at the University Hospital in Brazil. Epidemiological data were obtained through the analysis of medical records and laboratory tests. By PCR analysis, we investigated the presence of virulence factors (VFs), pathogenicity islands (PAIs), extended-spectrum ß-lactamase (ESBL), phylogenetic classifications (A, B1, B2, C, D, E, and F) and molecular genotype by enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). The mortality analysis showed that 33.3% of the deaths were associated with bacteraemia due to E. coli infections; in addition, an age between 60 and 75 years (p < 0.001; OR = 6.3[2.1-18.9]) and bacteraemia with an abdominal origin (p = 0.02; OR = 5[1.2-20.5]) were risk factors for the severity of the infection. Additionally, the presence of the afa gene was associated with mortality due to E. coli bacteraemia (p = 0.027; OR = 11.4[1.5-85.7]). Immunosuppression (27.1%), intestinal diseases (25.0%) and diabetes (18.8%), were prevalent among patients, and most of the bacteraemia cases were secondary to urinary tract infections (50.0%). The serum resistance gene traT was present in 77.1% of isolates, group capsular 2 (kpsMT II) was present in 45.8% and the K5 capsule was present in 20.8% of isolates. The isolates also showed a high prevalence for the siderophore yersiniabactina (fyuA) (70.8%) and PAI IV536 (77.1%). Phylogenetic analysis showed that group B2 (45.8%) was the most prevalent, and was the phylogroup that had a higher prevalence of VFs and PAIs. However, in this study, a considerable number of isolated bacteria were classified as group B1 (18.8%) and as group E (14.6%). Eight (16.7%) isolates were resistant to third and fourth generation cephalosporin and group CTX-M-1 (CTX-M-15) was the most prevalent ESBL type. The molecular genotyping showed two clonal lineages and several isolates that were not related to each other. This study provides additional information on the epidemiological and molecular characteristics of E. coli bloodstream infections in Brazil.

Draft Genome Sequence of Vancomycin-Resistant Enterococcus faecium UEL170 (Sequence Type 412), Isolated from a Patient with Urinary Tract Infection in a Tertiary Hospital in Southern Brazil.

Enterococcus faecium is a leading cause of health care-associated infections, with specific lineages circulating in hospital settings worldwide. Here, we report the draft genome sequence of the multidrug-resistant and biofilm-producing E. faecium UEL170, sequence type 412 (ST412), isolated from an inpatient with a urinary tract infection. This strain is a member of clonal complex 17 (CC17), a globally hospital-associated clone.

Disseminated Clonal Complex 5 (CC5) methicillin-resistant Staphylococcus aureus SCCmec type II in a tertiary hospital of Southern Brazil.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of human infections worldwide, with major dominant lineage circulating in particular geographical regions. The Brazilian Epidemic Clone (BEC, SCCmec III, ST 239) has been predominant in most Brazilian hospitals. Here, we report the prevalence of MRSA SCCmec type II exhibiting different STs, most of them belonging to CC5 in a tertiary hospital in Southern Brazil.

Microbiological environmental contamination in a Pediatric Intensive Care Unit / Contaminação ambiental microbiológica em Unidade de Terapia Intensiva Pediátrica / Contaminación ambiental microbiológica en una Unidad de Cuidados Intensivos Pediátricos

Background and objectives: inanimate surfaces and equipment in the hospital environment are considered reservoirs of resistant and pathogenic microorganisms. In Pediatric Intensive Care Units, the risk of infection is also related to the severity of pathologies associated with the immaturity of the immune system of this population. This study aimed to investigate microbiological environmental contamination in a Pediatric Intensive Care Unit. Method: this is an exploratory cross-sectional study, carried out in a Pediatric Intensive Care Unit of a highly complex university hospital, located in southern Brazil. To assess environmental contamination, sterile swabs were rubbed on surfaces corresponding to the patient unit and in the common area. Results: twenty-eight surfaces were analyzed, 12 of which were located in units occupied by patients at the time of collection and 16 surfaces in the common use area. In the total number of surfaces analyzed by microbiological cultures, the patient unit showed 66.67% contamination by microorganisms, while surfaces in the common area showed 56.25%. Regarding the microbiological profile, all isolated microorganisms were Gram-positive and showed resistance, namely Staphylococcus aureus and coagulase-negative Staphylococcus. Conclusion: there was evidence of a high frequency of contamination on inanimate surfaces and equipment near and far from patients, essentially by pathogenic and multi-resistant microorganisms to antimicrobials.(AU)

Justificativa e objetivos: superfícies e equipamentos inanimados no ambiente hospitalar são considerados reservatórios de microrganismos resistentes e patogênicos. Nas Unidades de Cuidados Intensivos Pediátricos, o risco de infeção também está relacionado com a gravidade das patologias associadas à imaturidade do sistema imunitário desta população. Este estudo teve como objetivo investigar a contaminação microbiológica ambiental em uma Unidade de Terapia Intensiva Pediátrica. Método: trata-se de um estudo exploratório transversal, realizado em uma Unidade de Terapia Intensiva Pediátrica de um hospital universitário de alta complexidade, localizado no Sul do Brasil. Para avaliar a contaminação ambiental, foram esfregados swabs estéreis nas superfícies correspondentes à unidade do paciente e na área comum. Resultados: foram analisadas vinte e oito superfícies, sendo 12 localizadas em unidades ocupadas por pacientes no momento da coleta e 16 superfícies em área de uso comum. No total de superfícies analisadas por culturas microbiológicas, a unidade paciente apresentou 66,67% de contaminação por microrganismos, enquanto as superfícies da área comum apresentaram 56,25%. Quanto ao perfil microbiológico, todos os microrganismos isolados eram Gram-positivos e apresentavam resistência, nomeadamente Staphylococcus aureus e Staphylococcus coagulase-negativa. Conclusão: houve evidência de elevada frequência de contaminação em superfícies inanimadas e equipamentos próximos e distantes dos pacientes, essencialmente por microrganismos patogênicos e multirresistentes aos antimicrobianos.(AU)

Fundamento y objetivos: las superficies y equipos inanimados del ambiente hospitalario son considerados reservorios de microorganismos resistentes y patógenos. En las Unidades de Cuidados Intensivos Pediátricos el riesgo de infección también se relaciona con la gravedad de patologías asociadas a la inmadurez del sistema inmunológico de esta población. Este estudio tuvo como objetivo investigar la contaminación ambiental microbiológica en una Unidad de Cuidados Intensivos Pediátricos. Método: se trata de un estudio exploratorio transversal, realizado en una Unidad de Cuidados Intensivos Pediátricos de un hospital universitario de alta complejidad, ubicado en el sur de Brasil. Para evaluar la contaminación ambiental se frotaron hisopos estériles en las superficies correspondientes a la unidad de pacientes y en el área común. Resultados: se analizaron veintiocho superficies, 12 de las cuales estaban ubicadas en unidades ocupadas por los pacientes en el momento de la recogida y 16 superficies en el área de uso común. Del total de superficies analizadas por cultivos microbiológicos, la unidad de pacientes presentó un 66,67% de contaminación por microorganismos, mientras que las superficies del área común presentaron un 56,25%. En cuanto al perfil microbiológico, todos los microorganismos aislados fueron Gram positivos y presentaron resistencia, concretamente Staphylococcus aureus y Staphylococcus coagulasa negativo. Conclusión: se evidenció alta frecuencia de contaminación en superficies inanimadas y equipos cercanos y lejanos de los pacientes, esencialmente por microorganismos patógenos y multirresistentes a los antimicrobianos.(AU)

Antimicrobial activity evaluation and comparison of methods of susceptibility for Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacter spp. isolates.

The production of KPC (Klebsiella pneumoniae carbapenemase) is the major mechanism of resistance to carbapenem agents in enterobacterias. In this context, forty KPC-producing Enterobacter spp. clinical isolates were studied. It was evaluated the activity of antimicrobial agents: polymyxin B, tigecycline, ertapenem, imipenem and meropenem, and was performed a comparison of the methodologies used to determine the susceptibility: broth microdilution, Etest® (bioMérieux), Vitek 2® automated system (bioMérieux) and disc diffusion. It was calculated the minimum inhibitory concentration (MIC) for each antimicrobial and polymyxin B showed the lowest concentrations for broth microdilution. Errors also were calculated among the techniques, tigecycline and ertapenem were the antibiotics with the largest and the lower number of discrepancies, respectively. Moreover, Vitek 2® automated system was the method most similar compared to the broth microdilution. Therefore, is important to evaluate the performance of new methods in comparison to the reference method, broth microdilution.

Comparison of HRM analysis and three REP-PCR genomic fingerprint methods for rapid typing of MRSA at a Brazilian hospital.

INTRODUCTION: Infections caused by multidrug-resistant bacteria are increasingly common and represent a serious problem for public health. Staphylococcus aureus is one of the major agents of infections, and methicillin-resistant S. aureus (MRSA) has spread worldwide. The aim of this study was to phenotypically and genotypically characterize 55 MRSAs isolated in the University Hospital of Londrina, Paraná, Brazil, during 2010. METHODOLOGY: Bacterial isolates were characterized based on their antimicrobial susceptibility profile, biofilm production capacity, and staphylococcal chromosome cassette mec (SCCmec) type. Determination of clonal groups was performed by polymerase chain reaction using the RW3A, JB1, and BOX A1R primers and high-resolution melting (HRM) analysis. RESULTS: The majority of isolates harbored SCCmec type II. SCCmec III, characteristic of the Brazilian endemic clone, was observed in four strains. Only two isolates harbored SCCmec type IV, which is common in community-acquired MRSA strains. Most isolates also showed resistance to more than four of the tested antimicrobials, and 30 isolates exhibited the ability to produce biofilm. DNA polymorphism analysis showed a higher discriminatory power for the JB1 primer, but RW3A revealed several clonal groups of MRSA with similar genotypic and phenotypic characteristics. HRM analysis showed eight different sequence types. CONCLUSIONS: These results are important for epidemiological studies involving MRSA infections.

Molecular and phenotypic characteristics of methicillin-resistant Staphylococcus aureus isolated from hospitalized patients.

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of infections acquired in both community and hospital settings. In this study, MRSA isolated from different sources of hospitalized patients was characterized by molecular and phenotypic methods. METHODOLOGY: A total of 123 S. aureus isolates were characterized according to their genetic relatedness by repetitive element sequence based-PCR (REP-PCR), in vitro antimicrobial susceptibility profile, SCCmec typing and presence of seven virulence factor-encoding genes. RESULTS: REP-PCR fingerprinting showed low relatedness between the isolates, and the predominance of one specific lineage or clonal group was not observed. All isolates were susceptible to teicoplanin and linezolide. All isolates were resistant to cefoxitin and penicillin, and the majority were also resistant to one or more other antimicrobials. Fifty isolates (41.7%) were intermediately resistant to vancomycin. Most isolates harbored SCCmec type II (53.7%), followed by type I (22.8%), type IV (8.1%) and type III (1.6%). All isolates harbored at least two virulence factor-encoding genes, and the prevalence was as follows: coa, 100%; icaA, 100%; hla, 13.0%; hlb, 91.1%, hld, 91.1%; lukS-PV and lukF-PV, 2.4%; and tst, 34.1%. A positive association with the presence of hla and SCCmec type II, and tst and SCCmec type I was observed. CONCLUSION: This study showed the high virulence potential of multidrug-resistant MRSA circulating in a teaching hospital. A high prevalence of MRSA showing intermediate vancomycin resistance was also observed, indicating the urgent need to improve strategies for controlling the use of antimicrobials for appropriate management of S. aureus infections.

Effect of Eugenol against Streptococcus agalactiae and Synergistic Interaction with Biologically Produced Silver Nanoparticles.

Streptococcus agalactiae (group B streptococci (GBS)) is an important infections agent in newborns associated with maternal vaginal colonization. Intrapartum antibiotic prophylaxis in GBS-colonized pregnant women has led to a significant reduction in the incidence of early neonatal infection in various geographic regions. However, this strategy may lead to resistance selecting among GBS, indicating the need for new alternatives to prevent bacterial transmission and even to treat GBS infections. This study reported for the first time the effect of eugenol on GBS isolated from colonized women, alone and in combination with silver nanoparticles produced by Fusarium oxysporum (AgNPbio). Eugenol showed a bactericidal effect against planktonic cells of all GBS strains, and this effect appeared to be time-dependent as judged by the time-kill curves and viability analysis. Combination of eugenol with AgNPbio resulted in a strong synergistic activity, significantly reducing the minimum inhibitory concentration values of both compounds. Scanning and transmission electron microscopy revealed fragmented cells and changes in bacterial morphology after incubation with eugenol. In addition, eugenol inhibited the viability of sessile cells during biofilm formation and in mature biofilms. These results indicate the potential of eugenol as an alternative for controlling GBS infections.

Bacteremia causada por Staphylococcus aureus: Uma análise de quinze anos da sensibilidade a antimicrobianos em um hospital terciário do Brasil / Bacteremia caused by Staphylococcus aureus: a fifteen-year analysis of antimicrobial susceptibility in a tertiary hospital in Brazil / Bacteremia causada por Staphylococcus aureus: Un análisis de quince años de la sensibilidad a los antimicrobianos en un hospital terciario de Brasil

Justificativa e Objetivos: Infecções da corrente sanguínea por Staphylococcus aureus constituem uma das principais causas de morbidade e mortalidade em todo mundo. O tratamento de infecções por S. aureus é complexo, em parte, devido à elevada prevalência de resistência aos antimicrobianos. Compreender a epidemiologia e os padrões de resistência deste microrganismo é um ponto crítico para a prescrição empírica adequada de antimicrobianos. Assim, este estudo teve por objetivo avaliar a evolução de resistência antimicrobiana de S. aureus em um período de quinze anos. Métodos: Foram analisados os perfis de sensibilidade para os antimicrobianos ciprofloxacina (5µg); clindamicina (2µg); eritromicina (15µg); gentamicina (10µg); oxacilina (30µg); penicilina (10U); rifampicina (5µg); sulfametoxazol-trimetoprima (23.75/1.25µg) e tetraciclina (30µg) em 720 isolados de S. aureus provenientes de hemoculturas em um hospital terciário do sul do Brasil. Os valores de sensibilidade adotados foram aqueles contidos no CLSI, 2017. Os dados foram obtidos do Sistema de Informação AGTA Healthcare, módulo LABHOS®. Resultados: A frequência média de S. aureus resistente a meticilina foi de 43,74%. Com exceção de penicilina, ocorreu variação significativa da resistência para todos os antimicrobianos no período avaliado (ρ<0,001). Ciprofloxacina (51,14%), eritromicina (44,99%) e clindamicina (39,85%) apresentaram os maiores índices de resistência com tendência de aumento. Surpreendentemente, gentamicina (4%) e sulfametoxazol-trimetoprima (4%) apresentaram queda significativa nos percentuais de resistência. Para vancomicina, do ano 2010 a 2015, observou-se um aumento das concentrações inibitórias mínimas. Conclusão: Embora o índice de resistência tenha aumentado nos quinze anos para a maioria dos antimicrobianos, para sulfametoxazol-trimetoprima e gentamicina ocorreu redução significativa. Este estudo evidenciou, ainda, a emergência do fenótipo S. aureus com resistência intermediária a vancomicina.(AU)

Background and Objectives: Bloodstream infections caused by Staphylococcus aureus are a major cause of morbidity and mortality worldwide. Treatment of S. aureus infections is complex, in part, due to the high prevalence of antimicrobial resistance. Understanding the epidemiology and resistance patterns of this microorganism is a critical point for the proper empirical prescription of antimicrobials. Thus, this study aimed to evaluate the evolution of antimicrobial resistance of S. aureus in a period of fifteen years. Methods: Antimicrobial susceptibility profiles was determined for cefoxitin (30µg), penicillin (10 U), erythromycin (15 µg), clindamycin (2 µg), gentamycin (10 µg),ciprofloxacin (5 µg), sulfamethoxazole-trimethoprim (23.75/1.25 µg), rifampicin (5 µg), and tetracycline (30µg) in 720 S. aureus isolated from blood cultures in a tertiary hospital in southern Brazil were analyzed. Sensiblity values was determined according to Clinical Laboratory Standards Institute (CLSI, 2017).The data were obtained from the AGTA Healthcare Information System, LABHOS® module. Results: The mean frequency of methicillin-resistant S. aureus was 43.74%. Except for penicillin, there was a significant variation of resistance for all antimicrobials in the period evaluated (ρ<0.001). Ciprofloxacin (51.14%), erythromycin (44.99%) and clindamycin (39.85%) had the highest rates of resistance, with tendency to increase. Surprisingly, gentamicina (4%) and sulfamethoxazole-trimethoprim (4%) showed a significant percentage decrease in resistance. For vancomycin, from 2010 to 2015, it was observed an increase in minimum inhibitory concentrations. Conclusion: Although the resistance rate increased in the fifteen years for most antimicrobials, for sulfamethoxazole-trimethoprim and gentamicin a significant reduction occurred, indicating a possible clonal change. This study also evidenced the emergence of S. aureus with intermediate resistance to vancomycin phenotype.(AU)

Justificación y objetivos: Infecciones del flujo sanguíneo por Staphylococcus aureus constituyen una de las principales causas de morbilidad y mortalidad en todo el mundo. El tratamiento de las infecciones por S. aureus es complejo, en parte debido a la elevada prevalencia de resistencia a los antimicrobianos. Comprender la epidemiología y los patrones de resistencia de este microorganismo es un punto crítico para la prescripción empírica adecuada de antimicrobianos. Así, este estudio tuvo por objetivo evaluar la evolución de resistencia antimicrobiana de S. aureus en un período de quince años. Métodos: Se analizaron los perfiles de sensibilidad a los antimicrobianos ciprofloxacino (5µg); clindamicina (2µg); eritromicina (15 µg); gentamicina (10µg); oxacilina (30µg); penicilina (10U); rifampicina (5µg); sulfametoxazol-trimetoprima (23.75 / 1.25 µg) y tetraciclina (30µg) de 720 S. aureus aislados de hemocultivos de un hospital terciario del sur de Brasil. Los valores de sensibilidad adoptados fueron aquellos contenidos en el Clinical Laboratory Standards Institute (CLSI, 2017). Los datos fueron obtenidos del Sistema de Información AGTA Healthcare, módulo LABHOS®. Resultados: La frecuencia media de S. aureus resistente a meticilina fue de 43,74%. Con excepción de la penicilina, hubo variación significativa de la resistencia para todos los antimicrobianos en el período evaluado (ρ<0,001). Ciprofloxacino (51,14%), eritromicina (44,99%) y clindamicina (39,85%) presentaron los mayores índices de resistencia con tendencia de aumento. Sorprendentemente, gentamicina (4%) y sulfametoxazol-trimetoprim (4%) presentaron una caída significativa en los porcentajes de resistencia. Para vancomicina del año 2010 a 2015 se puede evidenciar un aumento de las concentraciones inhibitorias mínimas. Conclusiones: Aunque la resistencia a antimicrobianos aumentó en los quince años para la mayoría de los antimicrobianos, para sulfametoxazol-trimetoprim y gentamicina se produjo una reducción significativa, indicando un posible cambio clonal. Este estudio evidenció, además, la emergencia del fenotipo S. aureus con resistencia intermedia a vancomicina.(AU)