High frequency of increased triclosan MIC among CC5 MRSA and risk of misclassification of the SCCmec into types.

BACKGROUND: Typing of staphylococcal cassette chromosome mec (SCCmec) elements is commonly used for studies on the molecular epidemiology of MRSA. OBJECTIVES: To perform an investigation centred on uncovering the reasons for misclassification of MRSA clonal complex 5 (CC5) SCCmec type II clinical isolates in our laboratory. METHODS: MRSA isolates from CC5 were subjected to WGS and SCCmec typing. RESULTS: This investigation led to the discovery that the classification failure was due to an insertion of IS1272 carrying the fabI gene on a transposable element (TnSha1) that confers increased MIC to the biocide triclosan. Genomic analysis revealed that fabI was present in 25% of the CC5 MRSA isolates sampled. The frequency of TnSha1 in our collection was much higher than that observed among publicly available genomes (0.8%; n = 24/3142 CC5 genomes). Phylogenetic analyses revealed that genomes in different CC5 clades carry TnSha1 inserted in different integration sites, suggesting that this transposon has entered CC5 MRSA genomes on multiple occasions. In at least two genotypes, ST5-SCCmecII-t539 and ST5-SCCmecII-t2666, TnSha1 seems to have entered prior to their divergence. CONCLUSIONS: Our work highlights an important misclassification problem of SCCmecII in isolates harbouring TnSha1 when Boye's method is used for typing, which could have important implications for molecular epidemiology of MRSA. The importance of increased-MIC phenotype is still a matter of controversy that deserves more study given the widespread use of triclosan in many countries. Our results suggest expanding prevalence that may indicate strong selection for this phenotype.

Mechanisms of carbapenem resistance in endemic Pseudomonas aeruginosa isolates after an SPM-1 metallo-ß-lactamase producing strain subsided in an intensive care unit of a teaching hospital in Brazil.

Carbapenem-resistance mechanisms are a challenge in the treatment of Pseudomonas aeruginosa infections. We investigated changes in P. aeruginosa carbapenem-resistance determinants over a time period of eight years after the emergence of São Paulo metallo-ß-lactamase in a university hospital in Rio de Janeiro, Brazil. Patients admitted to the intensive care unit (ICU) were screened for P. aeruginosa colonisation and followed for the occurrence of infections from April 2007 to April 2008. The ICU environment was also sampled. Isolates were typed using random amplified polymorphic DNA, pulsed-field gel electrophoresis and multilocus sequence typing. Antimicrobial susceptibility was determined by disk diffusion and E-test, production of carbapenemases by a modified-CarbaNP test and presence of carbapenemase-encoding genes by polymerase chain reaction. Non-carbapenemase resistance mechanisms studied included efflux and AmpC overexpression by PAßN and cloxacillin susceptibility enhancement, respectively, as well as oprD mutations. From 472 P. aeruginosa clinical isolates (93 patients) and 17 isolates from the ICU environment, high genotypic diversity and several international clones were observed; one environment isolate belonged to the blaSPM-1 P. aeruginosa epidemic genotype. Among isolates from infections, 10 (29%) were carbapenem resistant: none produced carbapenemases, three exhibited all non-carbapenemase mechanisms studied, six presented a combination of two mechanisms, and one exclusively displayed oprD mutations. Carbapenem-resistant P. aeruginosa displayed a polyclonal profile after the SPM-1 epidemic genotype declined. This phenomenon is connected with blaSPM-1 P. aeruginosa replaced by other carbapenem-resistant pathogens.

Can habits and behaviors predict colonization by community-associated MRSA in patients admitted to a Brazilian hospital?

This study aimed to identify factors associated with colonization by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in adult patients admitted to a Brazilian hospital. This is a cross-sectional study, in which patients underwent a nasal swab and were asked about hygiene behavior, habits, and clinical history. Among the 702 patients, 180 (25.6%) had S. aureus and 21 (2.9%) MRSA. The factors associated with MRSA colonization were attending a gym (OR 4.71; 95% CI; 1.42 - 15.06), smoking habit in the last year (OR 2.37; 95% CI; 0.88 - 6.38), previous hospitalization (OR 2.18; CI 95%; 0.89 - 5.25), and shared personal hygiene items (OR 1.99; 95% CI; 0.71 - 5.55). At the time of admission, colonization by CA-MRSA isolates was higher than that found in the general population. This can be an important public health problem, already endemic in hospitals, whose factors such as those associated with habits (smoking cigarettes) and behaviors (team sports practice and activities in gyms) have been strongly highlighted. These findings may help developing infection control policies, allowing targeting patients on higher-risk populations for MRSA colonization.

Neisseria gonorrhoeae ST-1901 in Rio de Janeiro from 2006 to 2022: Phylogeny and antimicrobial resistance evolution of a well-succeeded pathogen.

Neisseria gonorrhoeae is a global threat to public health due to the accumulation of antimicrobial resistance mechanisms. ST-1901 is an internationally important sequence type (ST) because of its high incidence and the usual occurrence of chromosomally determined resistance. In this study, we describe the evolution of the ST-1901 and its single locus variants in Rio de Janeiro from 2006 to 2022. We analyzed 82 N. gonorrhoeae isolates according to antimicrobial susceptibility profile, resistance mechanisms, molecular typing, and phylogenetics. Six different single locus variants were detected. Phylogenetic analysis identified five clades, which share similar characteristics. Resistance rates for penicillin and tetracycline decreased due to the lower occurrence of resistance plasmids, but intermediary resistance to penicillin rose. Resistance to ciprofloxacin remained high throughout all clades and the years of the study. Regarding resistance to azithromycin, alterations in mtrR promoter and gene, and 23S rRNA encoding gene rrl were detected, with a notable rise in the incidence of C2611T mutations in more recent years occurring in four of five clades. In contrast, ß-lactam resistance associated penA 34 mosaic was found only in one persisting clade (Clade D), and unique G45D and A39T mutations in mtrR gene and its promoter (Nm-Like) were found only in Clade B. Taken together, these data suggest that ST-1901, a persistently circulating lineage of N. gonorrhoeae in Rio de Janeiro, has undergone changes over the years and may evolve to develop resistance to the current recommended dual therapy adopted in Brazil, namely, ceftriaxone and azithromycin.

RdJ detection tests to identify a unique MRSA clone of ST105-SCCmecII lineage and its variants disseminated in the metropolitan region of Rio de Janeiro.

Hospital bloodstream infection (BSI) caused by methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of morbidity and mortality and is frequently related to invasive procedures and medically complex patients. An important feature of MRSA is the clonal structure of its population. Specific MRSA clones may differ in their pathogenic, epidemiological, and antimicrobial resistance profiles. Whole-genome sequencing is currently the most robust and discriminatory technique for tracking hypervirulent/well-adapted MRSA clones. However, it remains an expensive and time-consuming technique that requires specialized personnel. In this work, we describe a pangenome protocol, based on binary matrix (1,0) of open reading frames (ORFs), that can be used to quickly find diagnostic, apomorphic sequence mutations that can serve as biomarkers. We use this technique to create a diagnostic screen for MRSA isolates circulating in the Rio de Janeiro metropolitan area, the RdJ clone, which is prevalent in BSI. The method described here has 100% specificity and sensitivity, eliminating the need to use genomic sequencing for clonal identification. The protocol used is relatively simple and all the steps, formulas and commands used are described in this work, such that this strategy can also be used to identify other MRSA clones and even clones from other bacterial species.

Vernonia polyanthes Less. (Asteraceae Bercht. & Presl), a Natural Source of Bioactive Compounds with Antibiotic Effect against Multidrug-Resistant Staphylococcus aureus.

Vernonia polyanthes is a medicinal plant used to treat many disorders, including infectious diseases. This study investigated the chemical constituents and the antibacterial activity of V. polyanthes leaf rinse extract (Vp-LRE). The chemical characterization of Vp-LRE was established using ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC/Q-TOF-MS), and glaucolide A was identified through 1H and 13C nuclear magnetic resonance (NMR) and mass fragmentation. The cytotoxicity was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). The antibacterial activity was assessed by minimal inhibitory concentration and minimal bactericidal concentration. Interactions between ligands and beta-lactamase were evaluated via molecular docking. UHPLC/Q-TOF-MS detected acacetin, apigenin, chrysoeriol, isorhamnetin, isorhamnetin isomer, kaempferide, 3',4'-dimethoxyluteolin, 3,7-dimethoxy-5,3',4'-trihydroxyflavone, piptocarphin A and glaucolide A. Vp-LRE (30 µg/mL) and glaucolide A (10 and 20 µg/mL) were cytotoxic against RAW 264.7 cells. Glaucolide A was not active, but Vp-LRE inhibited the Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Escherichia coli, Salmonella Choleraesuis and Typhimurium, with a bacteriostatic effect. The compounds (glaucolide A, 3',4'-dimethoxyluteolin, acacetin and apigenin) were able to interact with beta-lactamase, mainly through hydrogen bonding, with free energy between -6.2 to -7.5 kcal/mol. These results indicate that V. polyanthes is a potential natural source of phytochemicals with a significant antibiotic effect against MRSA strains.

The influence of carbapenem resistance on mortality in solid organ transplant recipients with Acinetobacter baumannii infection.

BACKGROUND: Infection with carbapenem-resistant Acinetobacter baumannii has been associated with high morbidity and mortality in solid organ transplant recipients. The main objective of this study was to assess the influence of carbapenem resistance and other potential risk factors on the outcome of A. baumannii infection after kidney and liver transplantation. METHODS: Retrospective study of a case series of A. baumannii infection among liver and renal transplant recipients. The primary outcome was death associated with A. baumannii infection. Multivariate logistic regression was used to assess the influence of carbapenem resistance and other covariates on the outcome. RESULTS: Forty-nine cases of A. baumannii infection affecting 24 kidney and 25 liver transplant recipients were studied. Eighteen cases (37%) were caused by carbapenem-resistant isolates. There were 17 (35%) deaths associated with A. baumannii infection. In unadjusted analysis, liver transplantation (p = 0.003), acquisition in intensive care unit (p = 0.001), extra-urinary site of infection (p < 0.001), mechanical ventilation (p = 0.001), use of central venous catheter (p = 0.008) and presentation with septic shock (p = 0.02) were significantly related to a higher risk of mortality associated with A. baumannii infection. The number of deaths associated with A. baumannii infection was higher among patients infected with carbapenem-resistant isolates, but the difference was not significant (p = 0.28). In multivariate analysis, the risk of A. baumannii-associated mortality was higher in patients with infection acquired in the intensive care unit (odds ratio [OR] = 34.8, p = 0.01) and on mechanical ventilation (OR = 15.2, p = 0.04). Appropriate empiric antimicrobial therapy was associated with significantly lower mortality (OR = 0.04, p = 0.03), but carbapenem resistance had no impact on it (OR = 0.73, p = 0.70). CONCLUSION: These findings suggest that A. baumannii-associated mortality among liver and kidney transplant recipients is influenced by baseline clinical severity and by the early start of appropriate therapy, but not by carbapenem resistance.

Pandemic clone USA300 in a Brazilian hospital: detection of an emergent lineage among methicillin-resistant Staphylococcus aureus isolates from bloodstream infections.

BACKGROUND: Staphylococcus aureus is one of the leading causes of bloodstream infections (BSI) worldwide. In Brazil, the hospital-acquired methicillin-resistant S. aureus USA100/SCCmecII lineage replaced the previously well-established clones. However, the emergence of community-associated (CA) MRSA lineages among hospitalized patients is an increasing issue. METHODS: Consecutive S. aureus isolates recovered from BSI episodes of patients admitted between January 2016 and December 2018 in a Brazilian teaching hospital were tested for antimicrobial resistance, their genotypic features were characterized, and the clinical characteristics of the patients were evaluated. RESULTS: A total of 123 S. aureus isolates were recovered from 113 patients. All isolates were susceptible to linezolid, teicoplanin and vancomycin and 13.8% were not susceptible to daptomycin. Vancomycin MIC50 and MIC90 of 2 mg/L were found for both MRSA and MSSA isolates. The MRSA isolation rate was 30.1% (37/123), and 51.4% of them carried the SCCmec type II, followed by SCCmecIV (40.5%). Among the 37 MRSA isolates, the main lineages found were USA100/SCCmecII/ST5 and ST105 (53.7%) and USA800/ST5/SCCmecIV (18.9%). Surprisingly, six (16%) CA-MRSA isolates, belonging to USA300/ST8/SCCmecIVa that carried PVL genes and the ACME cassette type I, were detected. These six patients with USA300 BSI had severe comorbidities, including cancer, and most had a Charlson score ≥ 5; furthermore, they were in wards attended by the same health professionals. MRSA isolates were associated with hospital acquired infections (p = 0.02) in more elderly patients (p = 0.03) and those diagnosed with hematologic cancer (p = 0.04). Among patients diagnosed with MRSA BSI, 19 (54.3%) died. CONCLUSIONS: The pandemic MRSA USA300 was detected for the first time in the Brazilian teaching hospital under study, and its cross-transmission most probably occurred between patients with BSI. This lineage may already be circulating among other Brazilian hospitals, which highlights the importance of carrying out surveillance programs to fight multidrug resistant and hypervirulent isolates.

Mitracarpus frigidus (Rubiaceae) inhibits inflammatory and oxidative stress mediators in Salmonella sp. mouse infection.

OBJECTIVES: Evaluation of the in-vivo anti-inflammatory activity of the methanolic extract obtained from the aerial parts of Mitracarpus frigidus (MFM) in the infection caused by two Salmonella strains and its chemical fingerprint by UFLC-quadrupole time of flight-MS. METHODS: The efficacy of MFM was investigated in a classical in-vivo Salmonella infection mouse model. A Salmonella reference strain (ATCC 13311) and a clinical isolate were used to infect mice and then MFM was orally administered during 14 days. At the end of the treatment with MFM, the infection and inflammatory levels were assayed. KEY FINDINGS: MFM treatment showed a significant reduction in mice mortality by Salmonella infection and, also, did not cause alterations in the liver function. Inhibitions of inflammatory and oxidative stress mediators [malondialdehyde (MDA), catalase, and metalloproteinase] were possibly involved in the observed effects. Chlorogenic acid, clarinoside, quercetin-pentosylhexoside, rutin, kaempferol-3O-rutinoside, kaempferol-rhamnosylhexoside and 2-azaanthraquinone were identified in MFM. CONCLUSIONS: MFM was effective in some inflammatory parameters, in the experimental conditions that were used in the study. The results presented in this study and the previous in-vitro anti-Salmonella activity reported by our research group reinforce the importance of MFM studies to considerer it as an alternative treatment for salmonellosis.

Luz UVC como estratégia de desinfecção do ar e superfícies hospitalares / Luz UV-C como estrategia de desinfección del aire y superficies hospitalarias / UVC light as a strategy for disinfection of hospital air and surfaces

Resumo Objetivo Avaliar a eficácia antimicrobiana de um dispositivo fixo emissor de luz UV-C na desinfecção de diferentes superfícies do ambiente hospitalar e sua eficácia antifúngica na qualidade do ar. Métodos Estudo quase-experimental realizado em uma unidade de internação hospitalar, que utilizou o Bioamostrador de ar Andersen® de seis estágios para análise do ar; e na avaliação das superfícies, utilizaram-se três suspensões de microrganismos (Acinetobacter sp. MDR, Escherichia coli e Klebsiella pneumoniae produtora de KPC) para contaminar o ambiente. Para ambos foram feitas coletas pré (controle) e pós-acionamento da luz UV-C (teste). Resultados Na avaliação do ar houve uma redução importante da contagem de colônias após a luz UV-C e não foram encontrados fungos patogênicos ou toxigênicos em nenhum dos dois momentos. Em relação à desinfecção das superfícies, nenhum crescimento bacteriano foi observado após a intervenção da luz, demonstrando 100% de inativação bacteriana nas condições testadas. Conclusão A utilização da tecnologia com emissão de luz UV-C fixa foi eficaz e pode ser considerada uma intervenção promissora para protocolos de desinfecção de superfícies hospitalares.

Resumen Objetivo Evaluar la eficacia antimicrobiana de un dispositivo fijo emisor de luz UV-C para la desinfección de diferentes superficies del ambiente hospitalario y su eficacia antifúngica en la calidad del aire. Métodos Estudio cuasi experimental realizado en una unidad de internación hospitalaria, en que se utilizó el biomuestreador de aire Andersen® de seis etapas para el análisis del aire. En el análisis de las superficies, se utilizaron tres suspensiones de microorganismos (Acinetobacter sp. MDR, Escherichia coli y Klebsiella pneumoniae productora de KPC) para contaminar el ambiente. En ambos se tomó una muestra antes (control) y después de accionar la luz UV-C (prueba). Resultados En el análisis del aire hubo una reducción importante del recuento de colonias después de la luz UV-C y no se encontraron hongos patógenos ni toxigénicos en ninguno de los dos momentos. Con relación a la desinfección de las superficies, no se observó ningún crecimiento bacteriano después de la intervención de la luz, lo que demuestra un 100 % de inactivación bacteriana en las condiciones analizadas. Conclusión El uso de la tecnología con emisión de luz UV-C fija fue eficaz y puede ser considerada una intervención prometedora para protocolos de desinfección de superficies hospitalarias.

Abstract Objective To evaluate a fixed UV-C light emitting device for its antimicrobial effectiveness in the disinfection of distinct surfaces and its antifungal effectiveness on air quality in the hospital environment. Methods This quasi-experimental study was conducted in a hospital inpatient unit, in which a six-stage air Biosampler (Andersen®) was used for air analysis. In the evaluation of surfaces, three suspensions of microorganisms (Acinetobacter sp. multidrug-resistant, Escherichia coli, and KPC-producing Klebsiella pneumoniae) were used to contaminate the environment. In both evaluations, pre- (control) and post-activation of UV-C light (test) collections were made. Results In the air evaluation, an important reduction was observed in the colony count after irradiation with UV-C light, and pathogenic or toxigenic fungi were not found in either of the two moments. Regarding the disinfection of surfaces, no bacterial growth was observed after the application of UV-C light, showing 100% bacterial inactivation under the tested conditions. Conclusion The use of fixed UV-C light emission technology was effective and can be considered a promising intervention for hospital surface disinfection protocols.

Kalanchoe brasiliensis Cambess., a Promising Natural Source of Antioxidant and Antibiotic Agents against Multidrug-Resistant Pathogens for the Treatment of Salmonella Gastroenteritis.

Kalanchoe brasiliensis Cambess. is a native Brazilian plant popularly known as "saião", and the juice of its fresh leaves is traditionally used to treat several disorders, including inflammatory and infectious processes such as dysentery. The goals of this study were to characterize the phytochemical composition and investigate the antioxidant activity, the antibiotic effect, and the mode of action against Salmonella of the hydroethanolic extracts from K. brasiliensis leaves collected in the summer and spring Brazilian seasons. These extracts had their chemical composition established by high-performance liquid chromatography with diode-array detection. Total phenolic and flavonoid contents were spectrophotometrically determined. 2,2-Diphenyl-1-picryl-hydrazyl radical scavenging, phosphomolybdenum reducing power and ß-carotene bleaching assays were carried out to evaluate the antioxidant capacity. Antibiotic potential was assessed by minimal inhibitory concentration against 8 bacterial ATCC® and 5 methicillin-resistant Staphylococcus aureus and 5 Salmonella clinical strains. The mode of action was investigated by time-kill, bacterial cell viability, and leakage of compounds absorbing at 280 nm assays against Salmonella. Chromatographic profile and UV spectrum analyses suggested the significant presence of flavonoid type patuletin and eupafolin derivatives, and no difference between both periods of collection was noted. Significant amounts of total phenolic and flavonoid contents and a promising antioxidant capacity were observed. Hydroethanolic extracts (70%, summer and spring) were the most active against the tested Gram-positive and Gram-negative bacterial strains, showing the bacteriostatic action of 5000 µg/mL. Time-kill data demonstrated that these extracts were able to reduce the Salmonella growth rate. Cell number was reduced with release of the bacterial content. Together, these results suggest that K. brasiliensis is a natural source of antioxidant and antibacterial agents that can be applied in the research and development of new antibiotics for the treatment of Salmonella gastroenteritis because they are able to interfere in the Salmonella growth, probably due to cell membrane damage.

Can habits and behaviors predict colonization by community-associated MRSA in patients admitted to a Brazilian hospital?

ABSTRACT This study aimed to identify factors associated with colonization by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in adult patients admitted to a Brazilian hospital. This is a cross-sectional study, in which patients underwent a nasal swab and were asked about hygiene behavior, habits, and clinical history. Among the 702 patients, 180 (25.6%) had S. aureus and 21 (2.9%) MRSA. The factors associated with MRSA colonization were attending a gym (OR 4.71; 95% CI; 1.42 - 15.06), smoking habit in the last year (OR 2.37; 95% CI; 0.88 - 6.38), previous hospitalization (OR 2.18; CI 95%; 0.89 - 5.25), and shared personal hygiene items (OR 1.99; 95% CI; 0.71 - 5.55). At the time of admission, colonization by CA-MRSA isolates was higher than that found in the general population. This can be an important public health problem, already endemic in hospitals, whose factors such as those associated with habits (smoking cigarettes) and behaviors (team sports practice and activities in gyms) have been strongly highlighted. These findings may help developing infection control policies, allowing targeting patients on higher-risk populations for MRSA colonization.

Endemic extended-spectrum beta-lactamase-producing Klebsiella pneumoniae at an intensive care unit: risk factors for colonization and infection.

A prospective cohort study was undertaken to describe the epidemiology of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBLKp) acquisition at an intensive care unit (ICU) in a non-outbreak setting. Surveillance for ESBLKp colonization and infection was performed in patients admitted at the ICU from January, 2000, to May, 2001. Screening for ESBLKp intestinal colonization was done by culturing rectal swab specimens at admission, 72 hr after admission and weekly until discharge or detection of ESBLKp. The incidence of ESBLKp intestinal colonization was 5.8/1,000 patient-days (95%CI, 3.4-10.1), and of ESBLKp infection was 1.7/1,000 patient-days (95%CI, 0.7-4.2). Use of vancomycin (OR 6.6; 95%CI, 1.73-25.28), amphotericin B (OR 12.0; 95%CI, 1.79-80.51), metronidazole (OR 5.3; 95%CI, 1.10-25.65), and ciprofloxacin (OR 0.1; 95%CI, 0.01-0.97) were independently associated with ESBLKp intestinal colonization. Previous ESBLKp colonization (OR 60.6; 95%CI, 56.33-578.73) was independently associated with ESBLKp infection. Each ICU-acquired ESBLKp isolate belonged to a different genotype by ERIC-PCR or pulsed-field gel electrophoresis (PFGE) and had a different plasmid profile, suggesting that cross transmission was not the main source for ESBLKp acquisition. Factors associated with ESBLKp in the non-outbreak setting were different from those previously reported during outbreaks. Intestinal ESBLKp colonization was confirmed as a risk factor for infection by this pathogen.

Imported and intensive care unit-born Acinetobacter baumannii clonal complexes: one-year prospective cohort study in intensive care patients.

The main objective of this study was to assess the frequency and possible sources of colonization and infection by Acinetobacter in the intensive care unit (ICU) of a university hospital in Rio de Janeiro, Brazil, and characterize the isolates for relatedness to internationally and locally disseminated lineages. Patients consecutively admitted to the ICU from April 2007 to April 2008 were screened for colonization and infection. Species were identified by rpoB sequencing. The presence of acquired and intrinsic carbapenemase genes was assessed by polymerase chain reaction (PCR). Strains were typed by random amplification of polymorphic DNA (RAPD)-PCR, pulsed-field gel electrophoresis, and multilocus sequence typing (MLST) using the schemes hosted at the University of Oxford (UO) and Institut Pasteur (IP). Of 234 patients, 98 (42%) had at least one specimen positive for the Acinetobacter isolate, and 24 (10%) had infection. A total of 22 (92%) infections were caused by Acinetobacter baumannii and one each (4%) by Acinetobacter nosocomialis and Acinetobacter berezinae. A. baumannii isolates from 60 patients belonged to RAPD types that corresponded to MLST clonal complexes (CCs) 109/1 (UO/IP scheme, known as International Clone I), CC 110/110 (UO/IP), CC 113/79 (UO/IP), and CC 104/15 (UO/IP). Most CCs were carbapenem resistant and carried the bla(OXA-23)-like gene. Strains were introduced by patients transferred from other wards of the same hospital (11 patients, 18%) or acquired from cross-transmission within the ICU (49 patients, 82%). A. nosocomialis lineage sequence type 260 colonized 10% of the whole study population. A. baumannii have become established in this hospital as a part of a global epidemic of successful clones. Once introduced into the hospital, such clones have become entrenched among patients in the ICU.

Mechanisms of carbapenem resistance in endemic Pseudomonas aeruginosa isolates after an SPM-1 metallo-β -lactamase producing strain subsided in an intensive care unit of a teaching hospital in Brazil

Carbapenem-resistance mechanisms are a challenge in the treatment of Pseudomonas aeruginosa infections. We investigated changes in P. aeruginosa carbapenem-resistance determinants over a time period of eight years after the emergence of São Paulo metallo-β-lactamase in a university hospital in Rio de Janeiro, Brazil. Patients admitted to the intensive care unit (ICU) were screened for P. aeruginosa colonisation and followed for the occurrence of infections from April 2007 to April 2008. The ICU environment was also sampled. Isolates were typed using random amplified polymorphic DNA, pulsed-field gel electrophoresis and multilocus sequence typing. Antimicrobial susceptibility was determined by disk diffusion and E-test, production of carbapenemases by a modified-CarbaNP test and presence of carbapenemase-encoding genes by polymerase chain reaction. Non-carbapenemase resistance mechanisms studied included efflux and AmpC overexpression by PAβN and cloxacillin susceptibility enhancement, respectively, as well as oprD mutations. From 472 P. aeruginosa clinical isolates (93 patients) and 17 isolates from the ICU environment, high genotypic diversity and several international clones were observed; one environment isolate belonged to the blaSPM-1 P. aeruginosa epidemic genotype. Among isolates from infections, 10 (29%) were carbapenem resistant: none produced carbapenemases, three exhibited all non-carbapenemase mechanisms studied, six presented a combination of two mechanisms, and one exclusively displayed oprD mutations. Carbapenem-resistant P. aeruginosa displayed a polyclonal profile after the SPM-1 epidemic genotype declined. This phenomenon is connected with blaSPM-1 P. aeruginosa replaced by other carbapenem-resistant pathogens.

Polyclonal presence of non-multiresistant methicillin-resistant Staphylococcus aureus isolates carrying SCCmec IV in health care-associated infections in a hospital in Rio de Janeiro, Brazil.

Change in epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) was observed because of the emergence of infections by non-multiresistant MRSA (nMRSA) in our hospital in Rio de Janeiro, Brazil. Clinical characterization and molecular analysis of 20 nMRSA isolates recovered from 17 patients, between February 2005 and March 2006, were performed. The analysis included SCCmec (staphylococcal cassette chromosome mec), pulsed field gel electrophoresis (PFGE), multilocus restriction fragment, and multilocus sequence typing. MICs for oxacillin and vancomycin and presence of Panton-Valentine leukocidin (PVL) genes were also investigated. All but 1 of the 20 isolates presented SCCmec type IV. PFGE clustered all isolates into 9 genotypes. MIC < or = 16 microg/mL to oxacillin was found for 65% of the isolates, whereas 80% exhibited MIC of 2 microg/mL for vancomycin. PVL-encoding genes were observed in 3 isolates. Polyclonal presence of nMRSA SCCmec IV was observed in our institution, including community and health care-associated isolates, which belonged to the sequence types (STs) 1 (clonal complex [CC1]), ST5 (CC5), ST8 and ST72 (CC8), ST97 (CC97), and 2 ST singletons (SLV5 and SLV30).

First reported case of infective endocarditis caused by community-acquired methicillin-resistant Staphylococcus aureus not associated with healthcare contact in Brazil.

We report here the first case of endocarditis due to CA-MRSA not associated with healthcare contact in Brazil in Brazil. A previously healthy patient presented with history of endocarditis following a traumatic wound infection. Patient had multiple positive blood cultures within 72 h of admission and met modified Duke's criterion for infective endocarditis. The isolate was typed as Staphylococcal cassette chromosome (SCC) mec type IV and was positive for presence of Panton-Valentine leukocidin (PVL). Increased incidence of CA-MRSA endocarditis is a challenge for the internist to choose the best empirical therapy. Several authors have suggested an empirical therapy with both a beta-lactam and an anti-MRSA agent for serious S. aureus infections. Our patient was treated with Vancomycin and made complete recovery in 3 months.