Detección de portadores de gérmenes multiresisttentes en la unidad de cuidado intensivo medico fundación cardioinfantil

Introducción: En Colombia la prevalencia de Staphylococcus aureus resistente a la meticilina (SARM) oscila entre 6% y 15% para el personal medico, entre el 13 % y el 26 % de SARM en pacientes atendidos en la unidades de cuidado intensivo, no se reportan gérmenes productores de Betalactamasas de espectro extendido (ESBL) en fosas nasales y se reportan cifras alarmantes para Enterococcus resistente a la Vancomicina (VRE). Objetivo: Determinar la prevalencia de portadores de microorganismos multiresistentes en pacientes que ingresan a la unidad de cuidado intensivo médico, y en personal asistencial dedicado su cuidado. Metodología: estudio descriptivo de corte transversal, se estudiaron 114 sujetos, se llevo a cabo toma de muestra nasal, faringe y rectal. Resultados: se encontró una prevalencia de 18 % en los pacientes (muestra nasal) y 12.5 % (muestra nasal) en el personal medico y paramédico para el SARM, y en muestra faringe para el personal asistencial una prevalencia de 6.3 % y 25.6 % para los pacientes, la prevalencia de ESBL fue 0% en muestra nasal y faringe para los dos grupos, en la muestra rectal se encontró una prevalencia de 7.3 % y 13.4 % para Klebsiella pneumoniae ESBL positivo y Escherichia coli ESBL respectivamente. Discusión: Las prevalencias encontradas en este estudio en comparación con datos publicados reflejan el uso racional de los antibióticos en la FCI-IC y la adherencia a los protocolos de vigilancia epidemiológica; lo cual no significa que no pueda existir una exposición del personal medico y paramédico al paciente colonizado. Palabras claves: Gérmenes multiresistentes – Infecciones Intrahospitalarias – SARM – ERV- BLEE Key words : multiresistant germs, hospital infections, ESBL, VRE, MRSA

Avaliação do impacto de uma intervenção restritiva do emprego de antimicrobianos para o controle de infecção hospitalar em pacientes internados em Unidade de Terapia Intensva

Medidas restritivas de controle de antimicrobianos têm sido propostas para controlar surtos epidêmicos de infecção por germes multirresistentes em hospitais, mas são escassas as publicações a respeito de sua eficácia. Em um estudo quaseexperimental com controles históricos, avaliou-se a efetividade de uma intervenção restritiva ao uso de antimicrobianos para controlar a emergência de germes multirresistentes em uma unidade de cuidados intensivos (UTI) de um hospital geral. Os Serviços de Controle de Infecção e Comissão de Medicamentos restringiu o uso de drogas antimicrobianas em pacientes hospitalizados na UTI a não mais que dois agentes simultaneamente, exceto em casos autorizados por aqueles serviços. A incidência de eventos clínicos e bacteriológicos foi comparada entre o ano que precedeu a intervenção e o ano que a seguiu. No total, 225 pacientes com idade igual ou maior de 15 anos , com infecção, internados na UTI por pelo menos 48 horas, foram estudados no ano precedente a intervenção e 263 no ano seguinte a ela. No ano seguinte à intervenção, um percentual menor de pacientes foi tratado simultaneamente com mais de dois antimicrobianos, mas não houve modificação no número total de antimicrobianos prescritos, na duração e no custo do tratamento. Mortalidade e tempo de internação foram similares nos dois períodos de observação. O número de culturas positivas aumentou depois da intervenção, tanto para germes Gram positivos, quanto para germes Gram negativos, principalmente devido ao aumento do número de isolados do trato respiratório. A maioria dos isolados foi Staphylococcus aureus dentre os Gram positivos e Acinetobacter sp dentre os germes Gram negativos. No ano seguinte à intervenção, a sensibilidade dos microorganismos Gram negativos para carbenicilina, ceftazidima e ceftriaxona aumentou, e para o imipenem diminuiu. A ausência de resposta dessa intervenção sobre desfechos clínicos pode ser em conseqüência da insuficiente aderência ou a sua relativa ineficácia. A melhora da sensibilidade microbiana de alguns germes, semaumento de custos ou a incidência de efeitos adversos, encoraja o uso de protocolos similares de restrição de drogas antimicrobianas para reduzir a taxa de resistência bacteriana na UTI.

Molecular characterization of clinical multiresistant isolates of Acinetobacter sp. from hospitals in Porto Alegre, State of Rio Grande do Sul, Brazil

INTRODUCTION: Hospitals around the world have presented multiresistant Acinetobacter sp. outbreaks. The spread of these isolates that harbor an increasing variety of resistance genes makes the treatment of these infections and their control within the hospital environment more difficult. This study aimed to evaluate the occurrence and dissemination of Acinetobacter sp. multiresistant isolates and to identify acquired resistance genes. METHODS: We analyzed 274 clinical isolates of Acinetobacter sp. from five hospitals in Porto Alegre, RS, Brazil. We evaluated the susceptibility to antimicrobial, acquired resistance genes from Ambler's classes B and D, and performed molecular typing of the isolates using enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) technique. RESULTS: A high (68%) percentage of multiresistant isolates of Acinetobacter sp. was observed, and 69% were resistant to carbapenems. We identified 84% of isolates belonging to species A. baumannii because they presented the gene blaOXA-51. The gene blaOXA-23 was detected in 62% of the isolates, and among these, 98% were resistant to carbapenems. Using the ERIC-PCR technique, we identified clones of Acinetobacter sp. spread among the four hospitals analyzed during the sampling period. CONCLUSIONS: The data indicate the dissemination of Acinetobacter sp. isolates among hospitals and their permanence in the hospital after one year.

Susceptibility of clinical isolates of multiresistant Pseudomonas aeruginosa to a hospital disinfectant and molecular typing

The aim of this study was to evaluate the susceptibility of 35 resistant Pseudomonas aeruginosa clinical isolates to a quaternary ammonium hospital disinfectant. The methodology was the AOAC Use-Dilution Test, with disinfectant at its use-concentration. In addition, the chromosomal DNA profile of the isolates were determined by macro-restriction pulsed field gel electrophoresis (PFGE) method aiming to verify the relatedness among them and the behavior of isolates from the same group regarding the susceptibility to the disinfectant. Seventy one percent of the isolates were multiresistant to antibiotics and 43% showed a reduced susceptibility to the disinfectant. The PFGE methodology detected 18 major clonal groups. We found isolates with reduced susceptibility to the disinfectant and we think that these are worrying data that should be further investigated including different organisms and chemical agents in order to demonstrate that microorganisms can be destroyed by biocide as necessary. We also found strains of the same clonal groups showing different susceptibility to the disinfectant. This is an interesting observation considering that only few works are available about this subject. PFGE profile seems not to be a reliable marker for resistance to disinfectants.

Biofilm production by multiresistant Corynebacterium striatumassociated with nosocomial outbreak

Corynebacterium striatum is a potentially pathogenic microorganism that causes nosocomial outbreaks. However, little is known about its virulence factors that may contribute to healthcare-associated infections (HAIs). We investigated the biofilm production on abiotic surfaces of multidrug-resistant (MDR) and multidrug-susceptible (MDS) strains of C. striatum of pulsed-field gel electrophoresis types I-MDR, II-MDR, III-MDS and IV-MDS isolated during a nosocomial outbreak in Rio de Janeiro, Brazil. The results showed that C. striatum was able to adhere to hydrophilic and hydrophobic abiotic surfaces. The C. striatum1987/I-MDR strain, predominantly isolated from patients undergoing endotracheal intubation procedures, showed the greatest ability to adhere to all surfaces. C. striatumbound fibrinogen to its surface, which contributed to biofilm formation. Scanning electron microscopy showed the production of mature biofilms on polyurethane catheters by all pulsotypes. In conclusion, biofilm production may contribute to the establishment of HAIs caused by C. striatum.

In vitro activities of tigecycline combined with other antimicrobials against multiresistant gram-positive and gram-negative pathogens.

OBJECTIVES: To test the activity of tigecycline combined with 16 antimicrobials in vitro against 22 gram-positive and 55 gram-negative clinical isolates. METHODS: Antibiotic interactions were determined by chequerboard and time-kill methods. RESULTS: By chequerboard, of 891 organism-drug interactions tested, 97 (11%) were synergistic, 793 (89%) were indifferent and 1 (0.1%) was antagonistic. Among gram-positive pathogens, most synergisms occurred against Enterococcus spp. (7/11 isolates) with the tigecycline/rifampicin combination. No antagonism was detected. Among gram-negative organisms, synergism was observed mainly with trimethoprim/sulfamethoxazole against Serratia marcescens (5/5 isolates), Proteus spp. (2/5) and Stenotrophomonas maltophilia (2/5), with aztreonam against S. maltophilia (3/5), with cefepime and imipenem against Enterobacter cloacae (3/5), with ceftazidime against Morganella morganii (3/5), and with ceftriaxone against Klebsiella pneumoniae (3/5). The only case of antagonism occurred against one S. marcescens with the tigecycline/imipenem combination. Selected time-kill assays confirmed the bacteriostatic interactions observed by the chequerboard method. Moreover, they revealed a bactericidal synergism of tigecycline with piperacillin/tazobactam against one penicillin-resistant Streptococcus pneumoniae and with amikacin against Proteus vulgaris. CONCLUSIONS: Combinations of tigecycline with other antimicrobials produce primarily an indifferent response. Specific synergisms, especially against enterococci and problematic gram-negative isolates, might be worth investigating in in vitro models and/or in animal models simulating the human environment.

Variation in clonality and antibiotic-resistance genes among multiresistant Salmonella enterica serotype typhimurium phage-type U302 (MR U302) from humans, animals, and foods

Since 1990 multiresistant (MR) Salmonella enterica serotype Typhimurium definitive phage-type (DT) 104 (MR DT104) and closely related phage types have emerged as a worldwide health problem in humans and food animals. In this study the presence of the bla(CARB-2) (ampicillin), cmlA (chloramphenicol), aadA2 (streptomycin/spectinomycin), sul1 (sulphonamide), and tetG (tetracycline) resistance genes in isolates of one such phage type, U302, have been determined. In addition bla(TEM) I primers have been used for the detection of TEM-type beta-lactamases. Isolates have also been characterized by plasmid profile and pulsed field gel electrophoresis (PFGE). Thirty-three of 39 isolates were positive for blaCARB-2, cmlA, aadA2, sul1 and tetG, four for bla(TEM), aadA2 and sul1, one for aadA2 and sul1, and one for blaTEM only. bla(TEM)-mediated ampicillin resistance was transferred to Escherichia coli K12 from three isolates along with other resistance markers, including resistance to chloramphenicol, streptomycin, spectinomycin, sulphonamides, and tetracyclines. Strains carried up to 6 plasmids and 34 plasmid profiles were identified. Although the majority of strains (33/39) produced a PFGE profile identical to that predominant in MR DT104, six different patterns were generated demonstrating the presence of various clones within MR U302. The results show that the majority of the MR U302 strains studied possessed the same antibiotic resistance genes as MR DT104. However, isolates with distinctive PFGE patterns can have different mechanisms of resistance to ampicillin, chloramphenicol, streptomycin, sulphonamides, and tetracyclines. Such resistance genes may be borne on transmissible plasmids.

Use of a LightCycler gyrA mutation assay for rapid identification of mutations conferring decreased susceptibility to ciprofloxacin in multiresistant Salmonella enterica serotype typhimurium DT104 isolates

A LightCycler-based PCR-hybridization gyrA mutation assay (GAMA) was developed to rapidly detect gyrA point mutations in multiresistant (MR) Salmonella enterica serotype Typhimurium DT104 with decreased susceptibility to ciprofloxacin (MIC, 0.25 to 1.0 mg/liter). Ninety-two isolates (49 human, 43 animal) were tested with three individual oligonucleotide probes directed against an Asp-87-to-Asn (GAC --> AAC) mutation, an Asp-87-to-Gly (GAC --> GGC) mutation, and a Ser-83-to-Phe (TCC --> TTC) mutation. Strains homologous to the probes could be distinguished from strains that had different mutations by their probe-target melting temperatures. Thirty-seven human and 30 animal isolates had an Asp-87-to-Asn substitution, 6 human and 6 animal isolates had a Ser-83-to-Phe substitution, and 5 human and 2 animal isolates had an Asp-87-to-Gly substitution. The remaining six strains all had mismatches with the three probes and therefore different gyrA mutations. The sequencing of gyrA from these six isolates showed that one human strain and two animal strains had an Asp-87-to-Tyr (GAC --> TAC) substitution and two animal strains had a Ser-83-to-Tyr (TCC --> TAC) substitution. One animal strain had no gyrA mutation, suggesting that this isolate had a different mechanism of resistance. Fifty-eight of the strains tested were indistinguishable by several different typing methods including antibiograms, pulsed-field gel gel electrophoresis, and plasmid profiling, although they could be further subdivided according to gyrA mutation. This study confirmed that MR DT104 with decreased susceptibility to ciprofloxacin from humans and food animals in England and Wales may have arisen independently against a background of clonal spread of MR DT104.

Finite determinacy and Whitney equisingularity of map germs from C(n) to C(2n-1)

We show that a holomorphic map germ f : (C(n), 0) -> (C(2n-1), 0) is finitely determined if and only if the double point scheme D(f) is a reduced curve. If n >= 3, we have that mu(D(2)(f)) = 2 mu(D(2)(f)/S(2))+C(f)-1, where D(2)(f) is the lifting of the double point curve in (C(n) x C(n), 0), mu(X) denotes the Milnor number of X and C(f) is the number of cross-caps that appear in a stable deformation of f. Moreover, we consider an unfolding F(t, x) = (t, f(t)(x)) of f and show that if F is mu-constant, then it is excellent in the sense of Gaffney. Finally, we find a minimal set of invariants whose constancy in the family f(t) is equivalent to the Whitney equisingularity of F. We also give an example of an unfolding which is topologically trivial, but it is not Whitney equisingular.

M-deformations of A-simple germs from R(n) to R(n+1)

All A-simple corank-1 germs from R(n) to R(n+1), where n not equal 4, have an M-deformation, that is a deformation in which the maximal numbers of isolated stable singular points are simultaneously present in the image.

A note on finite determinacy for corank 2 map germs from surfaces to 3-space

We study properties of finitely determined corank 2 quasihomogeneous map germs f: (C(2), 0) -> (C(3), 0). Examples and counter examples of such map germs are presented.

Real map germs and higher open book structures

The paper focusses on the existence of higher open book structures defined by real map germs psi : (R(m), 0) -> (R(p), 0) such that Sing psi boolean AND psi(-1)(0) subset of {0}. A general existence criterion is proved, with view to weighted-homogeneous maps.

Bi-Lipschitz A-triviality of map germs and Newton filtrations

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)