Identification of patellar tendon reflex based on simple kinematic measurement

This paper presents a method for quantifying tendon reflex dynamics addressing kinematical characteristics of the patellar tendon reflex. The method uses a limb-mounted three-dimensional motion sensor and an instrumented hammer to assess input-output relations of the patellar tendon reflex. A healthy adult male subject participated in our experiment. A simple rigid-body physical model was introduced to obtain viscoelastic and inertial responses of kinetic motion of the lower leg. This model is used to estimate knee extension torque by indicating the reflex responses of the muscle. A system identification method was then applied to describe the reflex responses to the hammer tapping by considering a second-order mathematical model with a delay term. Iterative prediction-error minimization was applied to the cascaded data for three tapping conditions: weak, medium, and strong. Good consistency was obtained between the analysis from the model and the measurement results. The results suggest that the proposed method was sufficiently feasible to characterize the reflex responses with a few characterized system parameters, which will be useful to provide additional quantitative assessment capability for neuromuscular diagnosis

Multidrug-resistant Pseudomonas Aeruginosa: An Endemic Problem In Brazil [pseudomonas Aeruginosa Multirresistente: Um Problema Endêmico No Brasil]

Global reports have documented the endemicity of multidrug-resistant (MDR) Pseudomonas aeruginosa associated with high levels of morbidity/mortality. In Brazil, outbreaks of MDR P. aeruginosa have been related to clonal dissemination. Currently, therapeutic options for the treatment of these infections are restricted to carbapenemic antibiotics (i.e., imipenem [IPM]). Thus, carbapenem resistance is a public health issue, since carbapenems are considered the last resort to nosocomial infections caused by MDR Gram-negative bacteria. In Brazil, the main mechanisms associated with MDR P. aeruginosa phenotypes are metallo-betalactamase (MBL) production (SPM-1 enzyme), presence of 16S rRNA methylase RmtD, loss of OprD porin, and overexpression of efflux pumps, which may explain the high level of carbapenem and aminoglycoside resistance. Accordingly, the emergence and dissemination of MDR strains is worrisome. Finally, based on national reports published by different groups of investigators, it is deduced that the convergence of multiple mechanisms of P. aeruginosa resistance has played a major role in the selection of endemic MDR clones widespread in Brazil.474409420Aedekerk, S., Characterization of a new efflux pump, MexGHI-OpmD, from Pseudomonas aeruginosa that confers resistance to vanadium (2002) Microbiology, 148 (8), pp. 2371-2381Aeschlimann, J.R., The role of multidrug efflux pumps in the antibiotic resistance of Pseudomonas aeruginosa and other gram-negative bacteria insights from the society of infectious diseases pharmacists (2003) Pharmacotherapy, 23 (7), pp. 916-924. , DOI 10.1592/phco.23.7.916.32722Andrade, S.S., Jones, R.N., Gales, A.C., Sader, H.S., Increasing prevalence of antimicrobial resistance among Pseudomonas aeruginosa isolates in Latin American medical centres: 5 year report of the SENTRY Antimicrobial Surveillance Program (1997-2001) [2] (2003) Journal of Antimicrobial Chemotherapy, 52 (1), pp. 140-141Andrade, S.S., Picao, R.C., Campana, E.H., Nicoletti, A.G., Pignatari, A.C.C., Gales, A.C., Influence of disk preparation on detection of metallo-β-lactamase- producing isolates by the combined disk assay (2007) Journal of Clinical Microbiology, 45 (6), pp. 2058-2060. , DOI 10.1128/JCM.02467-06Arakawa, Y., Shibata, N., Shibayama, K., Kurokawa, H., Yagi, T., Fujiwara, H., Goto, M., Convenient test for screening metallo-β-lactamase-producing gram- negative bacteria by using thiol compounds (2000) Journal of Clinical Microbiology, 38 (1), pp. 40-43Blair, J., Structure, function and inhibition of RND efflux pumps in Gram-negative bacteria: An update (2009) Current Opinion in Microbiology, 12 (5), pp. 512-519Butaye, P., Cloeckaert, A., Schwarz, S., Mobile genes coding for efflux-mediated antimicrobial resistance in Gram-positive and Gram-negative bacteria (2003) International Journal of Antimicrobial Agents, 22 (3), pp. 205-210. , DOI 10.1016/S0924-8579(03)00202-4Castanheira, M., Toleman, M.A., Jones, R.N., Schmidt, F.J., Walsh, T.R., Molecular characterization of a β-lactamase gene, bla GIM.1, encoding a new subclass of metallo-β-lactamase (2004) Antimicrobial Agents and Chemotherapy, 48 (12), pp. 4654-4661. , DOI 10.1128/AAC.48.12.4654-4661.2004Davies, J., Wright, G.D., Bacterial resistance to aminoglycoside antibiotics (1997) Trends in Microbiology, 5 (6), pp. 234-240. , DOI 10.1016/S0966-842X(97)01033-0De Freitas, A.L., Barth, A.L., Antibiotic resistance and molecular typing of Pseudomonas aeruginosa: Focus on imipenem (2002) Braz J Infect Dis, 6 (1), pp. 1-7Denny, B.J., Novotny, L., West, P.W.J., Blesova, M., Zamocka, J., Antimicrobial activity of a series of 1-alkyl-2-(4-pyridyl)pyridinium bromides against gram-positive and gram-negative bacteria (2005) Medical Principles and Practice, 14 (6), pp. 377-381. , DOI 10.1159/000088108Doi, Y., De Oliveira Garcia, D., Adams, J., Paterson, D.L., Coproduction of novel 16S rRNA methylase RmtD and metallo-β- lactamase SPM-1 in a panresistant Pseudomonas aeruginosa isolate from Brazil (2007) Antimicrobial Agents and Chemotherapy, 51 (3), pp. 852-856. , DOI 10.1128/AAC.01345-06Doi, Y., Adams-Haduch, J.M., Paterson, D.L., Genetic environment of 16S rRNA methylase gene rmtD (2008) Antimicrobial Agents and Chemotherapy, 52 (6), pp. 2270-2272. , DOI 10.1128/AAC.00037-08Doi, Y., Ghilardi, A.C.R., Adams, J., De Oliveira Garcia, D., Paterson, D.L., High prevalence of metallo-β-lactamase and 16S rRNA methylase coproduction among imipenem-resistant Pseudomonas aeruginosa isolates in Brazil (2007) Antimicrobial Agents and Chemotherapy, 51 (9), pp. 3388-3390. , DOI 10.1128/AAC.00443-07Doi, Y., Yokoyama, K., Yamane, K., Wachino, J.-I., Shibata, N., Yagi, T., Shibayama, K., Arakawa, Y., Plasmid-Mediated 16S rRNA Methylase in Serratia marcescens Conferring High-Level Resistance to Aminoglycosides (2004) Antimicrobial Agents and Chemotherapy, 48 (2), pp. 491-496. , DOI 10.1128/AAC.48.2.491-496.2004Doi, Y., Arakawa, Y., 16S ribosomal RNA methylation: Emerging resistance mechanism against aminoglycosides (2007) Clinical Infectious Diseases, 45 (1), pp. 88-94. , DOI 10.1086/518605El Salabi, A., (2009) Novel Subclase of a Group B1 Metallobeta-lactamase, TMB-1, in Clinical and Non-clinical Gram-negative Bacteria from Libya, , 49 th Interscience Conference in Antimicrobial Agentes and Chemotherapy ICAAC. San Francisco, CA, USA, n. C1-1365Evans, J.C., Segal, H., A novel insertion sequence, ISPa26, in oprD of Pseudomonas aeruginosa is associated with carbapenem resistance [2] (2007) Antimicrobial Agents and Chemotherapy, 51 (10), pp. 3776-3777. , DOI 10.1128/AAC.00837-07Fehlberg, L.C.C., (2010) Estudo Comparativo dos Mecanismos de Resistência Aos Beta-lactâmicos em Amostras Clínicas de Pseudomonas Aeruginosa Isoladas de Infecção de Corrente Sanguínea No Brasil e Nos Estados Unidos da América, , Dissertação Mestrado - Escola Paulista de Medicina, Universidade Federal de São PauloFigueiredo-Mendes, C.M., Sinto, S., Mello-Sampaio, J.L., Cardoso-Leao, S., Paz Oplustil, C., Turner, P., Veiga-Kiffer, C.R., Ykko, S., Pseudomonas aeruginosa clonal dissemination in Brazilian intensive care units (2005) Enfermedades Infecciosas y Microbiologia Clinica, 23 (7), pp. 402-405. , DOI 10.1157/13078798Filho, L.S., Determinação da produção de metalo-B-lactamases em amostras de P. aeruginosa isoladas em João Pessoa, Paraíba (2002) J Bras Patol Med Lab, 38 (4), pp. 291-296Fukuda, H., NfxC-type quinolone resistance in a clinical isolate of Pseudomonas aeruginosa (1995) Antimicrobial Agents and Chemotherapy, 39 (3), pp. 790-792Fung-Tomc, J.C., Activity of carbapenem BMS-181139 against Pseudomonas aeruginosa is not dependent on porin protein D2 (1995) Antimicrob Agents Chemother, 39 (2), pp. 386-393Furtado, G.H.C., D'Azevedo, P.A., Santos, A.F., Gales, A.C., Pignatari, A.C.C., Medeiros, E.A.S., Intravenous polymyxin B for the treatment of nosocomial pneumonia caused by multidrug-resistant Pseudomonas aeruginosa (2007) International Journal of Antimicrobial Agents, 30 (4), pp. 315-319. , DOI 10.1016/j.ijantimicag.2007.05.017, PII S0924857907002622Gales, A.C., Carbapenem-resistant Pseudomonas aeruginosa outbreak in an intensive care unit of a teaching hospital (2004) Braz J Infect Dis, 8 (4), pp. 267-271Gales, A.C., Menezes, L.C., Silbert, S., Sader, H.S., Dissemination in distinct Brazilian regions of an epidemic carbapenem-resistant Pseudomonas aeruginosa producing SPM metallo-β- lactamase (2003) Journal of Antimicrobial Chemotherapy, 52 (4), pp. 699-702. , DOI 10.1093/jac/dkg416Galimand, M., Plasmid-mediated high-level resistance to aminoglycosides in Enterobacteriaceae due to 16S rRNA methylation (2005) Antimicrob Agents Chemother, 47 (8), pp. 2565-2571Gonçalves, D.C., Detection of metallo-betalactamase in Pseudomonas aeruginosa isolated from hospitalized patients in Goiânia, state of Goiás (2009) Rev Soc Bras Med, 42 (4), pp. 411-414Huang, H., Hancock, R.E.W., The role of specific surface loop regions in determining the function of the imipenem-specific pore protein OprD of Pseudomonas aeruginosa (1996) Journal of Bacteriology, 178 (11), pp. 3085-3090Kaatz, G.W., Inhibition of bacterial efflux pumps: A new strategy to combat increasing antimicrobial agent resistance (2002) Expert Opinion on Emerging Drugs, 7 (2), pp. 223-233. , DOI 10.1517/14728214.7.2.223Khan, T.Z., Early pulmonary inflammation in infants with cystic fibrosis (1995) Am J Respir Crit Care Med, 151 (4), pp. 1075-1082Kiffer, C., Hsiung, A., Oplustil, C., Sampaio, J., Sakagami, E., Turner, P., Mendes, C., Antimicrobial susceptibility of gram-negative bacteria in Brazilian hospitals: The MYSTIC Program Brazil 2003 (2005) Brazilian Journal of Infectious Diseases, 9 (3), pp. 216-224. , http://www.scielo.br/pdf/bjid/v9n3/a04v9n3.pdfKohler, T., Michea-Hamzehpour, M., Epp, S.F., Pechere, J.-C., Carbapenem activities against Pseudomonas aeruginosa: Respective contributions of OprD and efflux systems (1999) Antimicrobial Agents and Chemotherapy, 43 (2), pp. 424-427Kohler, T., Epp, S.F., Curty, L.K., Pechere, J.-C., Characterization of MexT, the regulator of the MexE-MexF-OprN multidrug efflux system of Pseudomonas aeruginosa (1999) Journal of Bacteriology, 181 (20), pp. 6300-6305Kohler, T., Michea-Hamzehpour, M., Plesiat, P., Kahr, A.-L., Pechere, J.-C., Differential selection of multidrug efflux systems by quinolones in Pseudomonas aeruginosa (1997) Antimicrobial Agents and Chemotherapy, 41 (11), pp. 2540-2543Kokis, V.M., Moreira, B.M., Pellegrino, F.L.P.C., Silva, M.G., Long, J.B., Bastos, C.C.R., Santos, K.R.N., Identification of an imipenem-resistant Pseudomonas aeruginosa clone among patients in a hospital in Rio de Janeiro (2005) Journal of Hospital Infection, 60 (1), pp. 19-26. , DOI 10.1016/j.jhin.2004.11.019, PII S0195670105000022Kriengkauykiat, J., Porter, E., Lomovskaya, O., Wong-Beringer, A., Use of an efflux pump inhibitor to determine the prevalence of efflux pump-mediated fluoroquinolone resistance and multidrug resistance in Pseudomonas aeruginosa (2005) Antimicrobial Agents and Chemotherapy, 49 (2), pp. 565-570. , DOI 10.1128/AAC.49.2.565-570.2005Lauretti, L., Riccio, M.L., Mazzariol, A., Cornaglia, G., Amicosante, G., Fontana, R., Rossolini, G.M., Cloning and characterization of bla(VIM), a new integron-borne metallo- β-lactamase gene from a Pseudomonas aeruginosa clinical isolate (1999) Antimicrobial Agents and Chemotherapy, 43 (7), pp. 1584-1590Lee, K., Lim, Y.S., Yong, D., Yum, J.H., Chong, Y., Evaluation of the Hodge test and the imipenem-EDTA double-disk synergy test for differentiating metallo-β-lactamase-producing isolates of Pseudomonas spp. and Acinetobacter spp. (2003) Journal of Clinical Microbiology, 41 (10), pp. 4623-4629. , DOI 10.1128/JCM.41.10.4623-4629.2003Lee, K., Yum, J.H., Yong, D., Lee, H.M., Kim, H.D., Docquier, J.-D., Rossolini, G.M., Chong, Y., Novel acquired metallo-β-lactamase gene, bla SIM-1, in a class 1 integron from Acinetobacter baumannii clinical isolates from Korea (2005) Antimicrobial Agents and Chemotherapy, 49 (11), pp. 4485-4491. , DOI 10.1128/AAC.49.11.4485-4491.2005Levin, A.S., Barone, A.A., Penco, J., Santos, M.V., Marinho, I.S., Arruda, E.A.G., Manrique, E.I., Costa, S.F., Intravenous colistin as therapy for nosocomial infections caused by multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii (1999) Clinical Infectious Diseases, 28 (5), pp. 1008-1011Li, X.-Z., Poole, K., Nikaido, H., Contributions of MexAB-OprM and an EmrE homolog to intrinsic resistance of Pseudomonas aeruginosa to aminoglycosides and dyes (2003) Antimicrobial Agents and Chemotherapy, 47 (1), pp. 27-33. , DOI 10.1128/AAC.47.1.27-33.2003Li, X.Z., Zhang, L., Poole, K., Interplay between the MexA-MexB-OprM multidrug efflux system and the outer membrane barrier in the multiple antibiotic resistance of Pseudomonas aeruginosa (2000) Journal of Antimicrobial Chemotherapy, 45 (4), pp. 433-436Li, X.-Z., Livermore, D.M., Nikaido, H., Role of efflux pump(s) in intrinsic resistance of Pseudomonas aeruginosa: Resistance to tetracycline, chloramphenicol, and norfloxacin (1994) Antimicrobial Agents and Chemotherapy, 38 (8), pp. 1732-1741Li, X., Nikaido, H., Efflux-mediated drug resistance in bacteria an update (2009) Drugs, 69 (12), pp. 1555-1623Li, Y., Mima, T., Komori, Y., Morita, Y., Kuroda, T., Mizushima, T., Tsuchiya, T., A new member of the tripartite multidrug efflux pumps, MexVW-OprM, in Pseudomonas aeruginosa (2003) Journal of Antimicrobial Chemotherapy, 52 (4), pp. 572-575. , DOI 10.1093/jac/dkg390Lincopan, N., Balanoposthitis caused by Pseudomonas aeruginosa co-producing metallo-betalactamase and 16S rRNA methylase in children with hematological malignancies (2010) Int J Infect Dis, 14 (4), pp. e344-e347Lincopan, N., McCulloch, J.A., Reinert, C., Cassettari, V.C., Gales, A.C., Mamizuka, E.M., First isolation of metallo-β-lactamase-producing multiresistant Klebsiella pneumoniae from a patient in Brazil (2005) Journal of Clinical Microbiology, 43 (1), pp. 516-519. , DOI 10.1128/JCM.43.1.516-519.2005Lincopan, N., Trabulsi, L.R., Pseudomonas aeruginosa (2008) Microbiologia, 5, pp. 369-381. , TRABULSI, L. R.ALTERTHUM, F, ed. São Paulo: AtheneuLister, P.D., Antibacterial-resistant Pseudomonas aeruginosa: Clinical impact and complex regulation of chromosomally encoded resistance mechanisms (2009) Clin Microbiol Rev, 22 (4), pp. 582-610Livermore, D.M., Bacterial resistance: Origins, epidemiology, and impact (2003) Clinical Infectious Diseases, 36 (SUPPL. 1), pp. S11-S23. , DOI 10.1086/344654Livermore, D.M., Interplay of impermeability and chromosomal beta-lactamase activity in imipenemresistant Pseudomonas aeruginosa (1992) Antimicrob Agents Chemother, 36 (9), pp. 2046-2048Livermore, D.M., Multiple mechanisms of antimicrobial resistance in Pseudomonas aeruginosa: Our worst nightmare? (2002) Clinical Infectious Diseases, 34 (5), pp. 634-640. , DOI 10.1086/338782Livermore, D.M., Of Pseudomonas, porins, pumps and carbapenems (2001) Journal of Antimicrobial Chemotherapy, 47 (3), pp. 247-250Livermore, D.M., Woodford, N., Carbapenemases: A problem in waiting? (2000) Current Opinion in Microbiology, 3 (5), pp. 489-495Llanes, C., Hocquet, D., Vogne, C., Benali-Baitich, D., Neuwirth, C., Plesiat, P., Clinical Strains of Pseudomonas aeruginosa Overproducing MexAB-OprM and MexXY Efflux Pumps Simultaneously (2004) Antimicrobial Agents and Chemotherapy, 48 (5), pp. 1797-1802. , DOI 10.1128/AAC.48.5.1797-1802.2004Lomovskaya, O., Warren, M.S., Lee, A., Galazzo, J., Fronko, R., Lee, M., Blais, J., Lee, V.J., Identification and characterization of inhibitors of multidrug resistance efflux pumps in Pseudomonas aeruginosa: Novel agents for combination therapy (2001) Antimicrobial Agents and Chemotherapy, 45 (1), pp. 105-116. , DOI 10.1128/AAC.45.1.105-116.2001Luzzaro, F., Endimiani, A., Docquier, J.-D., Mugnaioli, C., Bonsignori, M., Amicosante, G., Rossolini, G.M., Toniolo, A., Prevalence and characterization of metallo-β-lactamases in clinical isolates of Pseudomonas aeruginosa (2004) Diagnostic Microbiology and Infectious Disease, 48 (2), pp. 131-135. , DOI 10.1016/j.diagmicrobio.2003.09.005Marchiaro, P., Mussi, M.A., Ballerini, V., Pasteran, F., Viale, A.M., Vila, A.J., Limansky, A.S., Sensitive EDTA-based microbiological assays for detection of metallo-β-lactamases in nonfermentative gram-negative bacteria (2005) Journal of Clinical Microbiology, 43 (11), pp. 5648-5652. , DOI 10.1128/JCM.43.11.5648-5652.2005Maseda, H., Yoneyama, H., Nakae, T., Assignment of the substrate-selective subunits of the MexEF-OprN multidrug efflux pump of Pseudomonas aeruginosa (2000) Antimicrobial Agents and Chemotherapy, 44 (3), pp. 658-664. , DOI 10.1128/AAC.44.3.658-664.2000Masuda, N., Sakagawa, E., Ohya, S., Gotoh, N., Tsujimoto, H., Nishino, T., Substrate specificities of MexAB-OprM, MexCD-OprJ, and MexXY-OprM efflux pumps in Pseudomonas aeruginosa (2000) Antimicrobial Agents and Chemotherapy, 44 (12), pp. 3322-3327. , DOI 10.1128/AAC.44.12.3322-3327.2000Masuda, N., Ohya, S., Cross-resistance to meropenem, cephems, and quinolones in Pseudomonas aeruginosa (1992) Antimicrob Agents Chemother, 36 (9), pp. 1847-1851Mendes, C., Oplustil, C., Sakagami, E., Turner, P., Kiffer, C., Antimicrobial susceptibility in intensive care units: MYSTIC Program Brazil 2002 (2005) Brazilian Journal of Infectious Diseases, 9 (1), pp. 44-51. , http://www.scielo.br/pdf/bjid/v9n1/24444.pdfMendes, R.E., Metalo-β-lactamases (2006) J Bras Patol Med Lab, 42 (2), pp. 103-113Mesaros, N., Glupczynski, Y., Avrain, L., Caceres, N.E., Tulkens, P.M., Van Bambeke, F., A combined phenotypic and genotypic method for the detection of Mex efflux pumps in Pseudomonas aeruginosa (2007) Journal of Antimicrobial Chemotherapy, 59 (3), pp. 378-386. , DOI 10.1093/jac/dkl504Mima, T., Sekiya, H., Mizushima, T., Kuroda, T., Tsuchiya, T., Gene cloning and properties of the RND-type multidrug efflux pumps MexPQ-OpmE and MexMN-OprM from Pseudomonas aeruginosa (2005) Microbiology and Immunology, 49 (11), pp. 999-1002. , http://www.jstage.jst.go.jp/article/mandi/49/11/999/_pdfMima, T., Joshi, S., Gomez-Escalada, M., Schweizer, H.P., Identification and characterization of TriABC-OpmH, a triclosan efflux pump of Pseudomonas aeruginosa requiring two membrane fusion proteins (2007) Journal of Bacteriology, 189 (21), pp. 7600-7609. , DOI 10.1128/JB.00850-07Mine, T., Morita, Y., Kataoka, A., Mizushima, T., Tsuchiya, T., Expression in Escherichia coli of a new multidrug efflux pump, MexXY, from Pseudomonas aeruginosa (1999) Antimicrobial Agents and Chemotherapy, 43 (2), pp. 415-417Muller-Premru, M., Lejko-Zupanc, T., Epidemiological typing of imipenem-resistant Pseudomonas aeruginosa (2002) International Journal of Antimicrobial Agents, 20 (5), pp. 380-383. , DOI 10.1016/S0924-8579(02)00193-0, PII S0924857902001930Murphy, T.A., Crystal structure of Pseudomonas aeruginosa SPM-1 provides insights into variable zinc affinity of metallo-b-lactamases (2006) Journal of Molecular Biology, 357 (3), pp. 890-903Neves, P.R., (2010) Alterações da Permeabilidade e Expressão de Bombas de Efluxo em Isolados Clínicos de Pseudomonas Aeruginosa Resistente ao Imipenem, , Tese Doutoramento - Faculdade de Ciências Farmacêuticas, Universidade de São PauloNeves, P.R., Multirresistência mediada por metalo-beta-lactamases, porinas, bombas de efluxo e metilases, em isolados clínicos de Pseudomonas aeruginosa (2008) XI CONGRESSO Brasileiro de Controle de Infecção e Epidemiologia Hospitalar, 12, p. 30. , Rio de Janeiro. Braz J Infec DisNicasio, A.M., The current state of multidrugresistant Gram-negative bacilli in North America (2008) Pharmacotherapy, 28 (2), pp. 235-249Nikaido, H., Porins and specific diffusion channels in bacterial outer membranes (1994) Journal of Biological Chemistry, 269 (6), pp. 3905-3908Nikaido, H., Nikaido, K., Harayama, S., Identification and characterization of porins in Pseudomonas aeruginosa (1991) Journal of Biological Chemistry, 266 (2), pp. 770-779Ochis, M., Negative regulation of the Pseudomonas aeruginosa outer membrane porin OprD selective for imipenem and basic amino acids (1999) Antimicrob Agents Chemother, 43 (5), pp. 1085-1090Oh, E.J., Prevalence of metallo-β-lactamase among Pseudomonas aeruginosa and Acinetobacter baumannii in a Korean university hospital and comparison of screening methods for detecting metallo-β-lactamase (2003) J Microbiol Methods, 54 (3), pp. 411-418Oliveira, M.S., Polymyxin B and colistimethate are comparable as to efficacy and renal toxicity (2009) Diagn Microbiol Infect Dis, 65 (4), pp. 431-434Pagès, J.M., The porin and the permeating antibiotic: A selective diffusion barrier in Gram-negative bacteria (2008) Nat Rev Microbiol, 6 (12), pp. 893-903Pearson, J.P., Van Delden, C., Iglewski, B.H., Active efflux and diffusion are involved in transport of Pseudomonas aeruginosa cell-to-cell signals (1999) Journal of Bacteriology, 181 (4), pp. 1203-1210Costa Pellegrino, F.L.P., Martins Teixeira, L., Siqueira Carvalho, M.D.G., Aranha Nouer, S., Pinto De Oliveira, M., Mello Sampaio, J.L., D'Avila Freitas, A., Meurer Moreira, B., Occurrence of a multidrug-resistant Pseudomonas aeruginosa clone in different hospitals in Rio de Janeiro, Brazil (2002) Journal of Clinical Microbiology, 40 (7), pp. 2420-2424. , DOI 10.1128/JCM.40.7.2420-2424.2002Picao, R.C., Andrade, S.S., Nicoletti, A.G., Campana, E.H., Moraes, G.C., Mendes, R.E., Gales, A.C., Metallo-β-lactamase detection: Comparative evaluation of double-disk synergy versus combined disk tests for IMP-, GIM-, SIM-, SPM-, or VIM-producing isolates (2008) Journal of Clinical Microbiology, 46 (6), pp. 2028-2037. , DOI 10.1128/JCM.00818-07Piddock, L.J., Clinically relevant chromosomally encoded multidrug resistance efflux pumps in bacteria (2006) Clin Microbiol Rev, 19 (2), pp. 382-402Poirel, L., Collet, L., Nordmann, P., Carbapenem-hydrolyzing metallo-β-lactamase from a nosocomial isolate of Pseudomonas aeruginosa in France [2] (2000) Emerging Infectious Diseases, 6 (1), pp. 84-85Poirel, L., Characterization of bla DIM-1, a novel integronlocated metallo-β-lactamase gene from a Pseudomonas stutzeri clinical isolate in the Netherlands (2009) 19 th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID), O309. , Helsinki, FinlandPoole, K., Efflux-mediated antimicrobial resistance (2005) Journal of Antimicrobial Chemotherapy, 56 (1), pp. 20-51. , DOI 10.1093/jac/dki171Poole, K., Tetro, K., Zhao, Q., Neshat, S., Heinrichs, D.E., Bianco, N., Expression of the multidrug resistance operon mexA-mexB-oprM in Pseudomonas aeruginosa: mexR encodes a regulator of operon expression (1996) Antimicrobial Agents and Chemotherapy, 40 (9), pp. 2021-2028Poole, K., Krebes, K., McNally, C., Neshat, S., Multiple antibiotic resistance in Pseudomonas a

Carbapenem-resistant Acinetobacter baumannii outbreak at university hospital Caracterização de cepas de Acinetobacter baumannii durante um surto de infecção hospitalar

Nineteen clonally related imipenem-resistant Acinetobacter baumannii isolates were recovered from eight intensive care unit patients. All isolates harboured blaOXA-51-like &#946;-lactamase genes and showed the absence of 22 kDa fraction in outer membrane porin profile analysis. It suggests a combination of two mechanisms as responsible for carbapenemresistant phenotypes.<br>Foram isoladas 19 cepas monoclonais de 8 pacientes da unidade de terapia intensiva, resistentes aos carbapenêmicos. Todas as cepas apresentaram o gene blaOXA-51-like e por análise do perfil de proteínas de membrana notou-se ausência da fração de 22 kDa, sugerindo a combinação de dois mecanismos de resistência aos carbapenêmicos

Detection of metallo-beta-lactamases-encoding genes in environmental isolates of Aeromonas hydrophila and Aeromonas jandaei

Aims: To determine the prevalence and expression of metallo-beta-lactamases (MBL)-encoding genes in Aeromonas species recovered from natural water reservoirs in southeastern Brazil. Methods and Results: Eighty-seven Aeromonas isolates belonging to Aeromonas hydrophila (n = 41) and Aer. jandaei (n = 46) species were tested for MBL production by the combined disk test using imipenem and meropenem disks as substrates and EDTA or thioglycolic acid as inhibitors. The presence of MBL genes was investigated by PCR and sequencing using new consensus primer pairs designed in this study. The cphA gene was found in 97.6% and 100% of Aer. hydrophila and Aer. jandaei isolates, respectively, whereas the acquired MBL genes bla(IMP), bla(VIM) and bla(SPM-1) were not detected. On the other hand, production of MBL activity was detectable in 87.8% and 10.9% of the cphA-positive Aer. hydrophila and Aer. jandaei isolates respectively. Conclusions: Our results indicate that cphA seems to be intrinsic in the environmental isolates of Aer. hydrophila and Aer. jandaei in southeastern Brazil, although, based on the combined disk test, not all of them are apparently able to express the enzymatic activity. Significance and Impact of the Study: These data confirm the presence of MBL-producing Aeromonas species in natural water reservoirs. Risk of water-borne diseases owing to domestic and industrial uses of freshwater should be re-examined from the increase of bacterial resistance point of view.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[2007/02266-7]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[2007/02238-3]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Financiadora de Estudos e Projetos (FINEP)Financiadora de Estudos e Projetos (FINEP)[0934/07

Risk factors for colonisation of newborn infants during an outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in an intermediate-risk neonatal unit

We describe a cross-sectional, survey to identify risk factors for colonisation of neonates by extended-spectrum P-Lactamase (ESBL)-producing Klebsiella pneumoniae. This occurred following exposure to a colonised healthcare worker during an outbreak in an intermediate-risk neonatal. unit. In total, 120 neonates admitted consecutively during a three-month period were screened for ESBL-producing K. pneumoniae by rectal swabbing and 27 were identified as colonised. Multivariate analysis showed colonisation to be independently associated with use of antibiotics and absence of breastfeeding. Previous use of antibiotics presented an odds ratio (OR) of 12.3 [95% confidence interval. (Cl): 3.66-41.2, P < 0.001]. The most commonly used antibiotics were penicillin and amikacin. Breastfeeding was associated with reduced risk for colonisation (OR: 0.22; 95% Cl: 0.05-0.99; P = 0.049). Nine isotates recovered during the first stage of the outbreak and 27 isolates from surveillance cultures were typed thereafter by pulsed-field gel electrophoresis, revealing six different profiles (A-F). Clones A, C, and E were implicated in the first stage of the outbreak, whereas among the 27 strains recovered from surveillance cultures, all six clones were identified. Clone A was also found on the hand of a nursing auxiliary with onychomycosis. We concluded that prior antimicrobial use predisposed to colonisation. The possible role of breastfeeding as a protective factor needs to be further elucidated. Detection of different genotypes of ESBL-producing K. pneumonioe suggests that dissemination of mobile genetic elements bearing the ESBL gene may have been superimposed on the simple dissemination of a clone during the outbreak. (c) 2008 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.CNPqConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CECOVISACECOVISAFAPESPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP