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Introduction: Plasmid-mediated class C ß-lactamase (pAmpC) is a member of broad-spectrum ß-lactamase that spreads worldwide. However, its prevalence was under-evaluated. Objective: To characterize the prevalence and distribution of pAmpC types in 294 cefoxitin (FOX) and third-generation cephalosporin (3GC) resistant Enterobacteriaceae collected in several regions of Thailand and Vietnam in 2018 and 2020. Methods: Multiplex Polymerase Chain Reaction (PCR) for pAmpC identification was utilized to investigate prevalence and diversification of pAmpC among 294 cefoxitin and third-generation cephalosporin resistant Enterobacteriaceae isolated from Thailand (n= 197) and Vietnam (n= 97). Results: The prevalence of pAmpC was 37.1 % found in second and third-generation cephalosporin resistant Enterobacteriaceae. CMY-2 like was prominent in Thailand and Vietnam; however, prevalence of CMY-2 was varied in each hospital. DHA contributed 25.7 %, ACT/MIR rate was dominant in Chiang Rai hospital, reached 100 % in Thanh Hoa Pediatrics hospital. Worrisome, 3.7 % - isolates carried two types of pAmpC. The incidence of pAmpC in Vietnam was significantly higher than those in Thailand. Conclusions: These findings provide evidence-based of highly spreading and diversified distribution of transferable AmpC among Enterobacteriaceae in two Asia-Pacific countries.

CMY-2 ß-lactamase is an important cause of ß-lactam resistance in Enterobacteriaceae and constitutes the most widespread pAmpC. Although CMY-2 has been previously recognized in our region, the real prevalence and epidemiology of this resistance marker was uncertain. During August-October 2009, we conducted a multicenter, prospective study to determine pAmpC prevalence and to characterize CMY-2 producing Escherichia coli associated plasmids. Plasmid-encoded AmpC prevalence was 0.9 % in enterobacteria in this period, being CMY- 2 prevalent and to a lesser extent DHA. Molecular typing of CMY-2- producing Escherichia coli isolates showed several lineages. Moreover, replicon typing of cmy-2- containing plasmids displayed a broad diversity in Inc/cmy- 2 links. Therefore, association of cmy-2 with specific transposon elements may be responsible for the spread of this resistance marker in Enterobacteriaceae.La ß-lactamasa de tipo AmpC de codificación plasmídica CMY-2 es la de mayor diseminación a nivel mundial en Enterobacteriaceae. Esta ha sido comunicada esporádicamente en nuestro país. Entre agosto y octubre de 2009 se llevó a cabo un estudio prospectivo y multicéntrico con el objetivo de determinar la prevalencia de pAmpC en nuestro medio y de caracterizar a los microorganismos productores y a los plásmidos portadores de estos marcadores de resistencia. La prevalencia de pAmpC plasmídicas en enterobacterias en este período fue de 0,9 %. La ß-lactamasa CMY-2 fue la enzima prevalente y, en menor medida, la DHA. La tipificación molecular de los aislamientos de Escherichia coli productores de CMY-2 mostró la presencia de distintos linajes, y los plásmidos portadores de cmy-2 pertenecieron a una amplia diversidad de grupos de incompatibilidad. Se determinó la asociación corriente arriba de cmy-2 con ISEcp1, el cual podría ser responsable de la amplia diseminación de este marcador de resistencia en Enterobacteriaceae.

Introduction: There is a growing increase in prosthetic joint infection (PJI) incidence due to cephalosporin-resistant bacteria, used in surgical prophylaxis. The replacement of these with glycopeptides has not been shown to improve the results, but they have been shown to improve with their combination., Methods: Comparative study of combination of teicoplanin and cefazolin before arthroplasty surgery against cefazolin alone from a previous control group., Results: During the control period, there were 16 PJIs from 585 surgeries, while in the intervention group there were 6 from 579 (incidence 2.7% vs. 1.03%, RR 0.4, P=.04). In control group, 11 of the infections were caused by Gram-positive bacteria versus 4 in the intervention group (1.8% vs. 0.7%, P=.08)., Conclusions: The addition of teicoplanin to cefazolin in the prophylaxis of arthroplasty surgery was associated with a reduction in the incidence of PJI, thanks to a decrease in infections caused by Gram-positive bacteria., (Copyright © 2019 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.)

Introduction: Urinary tract infection (UTI) is a common disease in the community, and a matter of concern due to the increasing resistance of microorganisms to first line antibiotics and the emergence of multiresistant strains producing extended spectrum beta lactamases (ESBL) in the community., Methods: An analytical case-control study was conducted over twelve months in 9 hospitals in Colombia. We collected isolates of E. coli, Klebsiella spp. and Proteus spp. from patients with community-onset UTI. The presence of ESBL, AmpC and KPC beta-lactamases were characterized by microbiological and molecular methods. The aim of this study was to determine factors related to the presence of these mechanisms of the resistance to third generation cephalosporins., Results: A total of 325 isolates (287 E. coli, 29 Klebsiella spp. and 9 Proteus spp.) were included. The most frequent comorbidities among the patients were hypertension (n=82; 25.2%) and diabetes mellitus (n=68; 20.9%). Previous use of antimicrobials was found in 23% of patients, and 29% had a previous UTI. Resistance to third and fourth generation cephalosporins varied between 3.4% and 6.3% in E. coli and between 6.9% and 17.8% in K. pneumoniae. Seven (2.4%) CTX-M-15 ESBL-producing E. coli isolates were detected; four of them belonged to ST 131 clone. In K. pneumoniae we detected three KPC-3 carbapenemases (10.3%)., Conclusions: This study confirms the emergence of resistance to third generation cephalosporins enterobacteriaceae as a cause of community-onset UTI. We emphasize the presence of ST 131 clone and KPC carbapenemases circulating in Colombia outside the hospital environment., (Copyright © 2011 Elsevier España, S.L. All rights reserved.)

Objectives: Determining the frequency of antimicrobial resistance amongst bacterial isolates obtained from patients in Intensive Care Units (ICU)., Methods: Study data relating to 2001 to 2003 regarding microbiological isolates was obtained from a laboratory network for the ICUs of 14 third-level hospitals in Bogotá belonging to the Bogotá Bacterial Resistance Control Group (BBRCG). 27,301 isolates were obtained and their susceptibility profiles were analysed using WHONET 5.3., Results: Staphylococcus aureus, Escherichia coli, coagulase negative Staphylococci (CNS), Pseudomonas aeruginosa y Klebsiella pneumoniae were the most commonly found microorganisms. Oxacillin-resistance rate ranged from 61% at 63% during 2001 to 2003 amongst S. aureus isolates and 78% to 83% amongst coagulase negative Staphylococci (CNS). E. coli resistance to third generation cephalosporines was found to be about 10% and over 20% to ciprofloxacin. K. pneumoniae isolates' resistance to third-generation cephalosporines was found to be more than 30% in 2001. P. aeruginosa resistance to all but a few antibiotics was found to be over 30% and multirresistance frequency was found to be 16% to 24%., Conclusion: The antimicrobial resistance rates found in the ICU of hospitals in Bogotá were higher than those reported in surveillance studies in the USA, Europe or other Latin-American cities.

Introduction: The increasing prevalence of high-level cephalosporin-resistant strains of Streptococcus pneumoniae could complicate the treatment of severe infections such as meningitis. There are still questions as to the characteristics of these strains, their ability to produce severe infection, and the inflammatory response they induce in CSF., Methods: Using a rabbit model of meningitis, we sought to determine the pathogenicity and differences in inflammatory parameters in two serotype 23F S. pneumoniae strains with different susceptibility to betalactams. Minimal inhibitory concentrations of the two strains were as follows: strain A--PEN 4 micro g/mL, CRO/CTX 2 micro g/mL--and strain B--PEN 0.12 micro g/mL, CRO/CTX 32 micro g/mL., Results: Strain A resulted in a greater incidence of secondary bacteremia and higher inflammatory parameters during the early phases of infection. Strain B caused brain edema, a more severe inflammatory response and significantly higher mortality at the end of the experiment., Conclusions: Both strains induced meningitis in the animal model. The differences in inflammatory response produced by the two strains could be related to the variations that determine the betalactam resistance level.

Background: Diseases produced by Streptoccocus pyogenes are still a problem in Chile, as in the rest of the world. It exhibits in vitro susceptibility to different antimicrobials, but penicillin continues to be the treatment of choice. Alternative drugs have been developed for allergic patients, such as erythromycin, new macrolides and cephalosporins. Nevertheless, resistant strains are appearing due to the indiscriminate use of macrolides., Aim: To assess present antimicrobial susceptibility of S Pyogenes strains isolated from chilean patients., Material and Methods: The susceptibility to penicillin, macrolides, clindamycin, cephalotin and vancomycin of 153 S Pyogenes strains, obtained from different health centers of the Metropolitan Region and isolated between 1996 and 1998, was assessed using the Kirby-Bauer method. Agar dilution minimal inhibitory concentration was then determined to macrolide resistant strains., Results: All strains were susceptible to penicillin. There was a 7.2% cross-resistance to macrolides., Conclusions: These results confirm that S Pyogenes resistance to macrolides has increased considerably in the Metropolitan Region of Chile during the last years.

Background: The aim of the study was to determine the frequency of third-generation cephalosporins and aztreonam resistance in gram-negative bacteria with inducible chromosomal beta-lactamase (beta Lac-ind) after beta-lactam therapy in the medical-surgical intensive care unit (ICU) at a university-affiliated hospital., Patients and Methods: We studied 34 infections in 29 patients admitted to the ICU. All were infected by strains with beta Lac-ind and all were treated with beta-lactam antibiotics. Susceptibility was determined by disc-diffusion. The beta-lactamase activity of those strains showing constitutive beta-lactamase overproduction were characterized by isoelectrofocusing. When this derepression occurred during the therapy, the strains were compared by genomic macrorestriction (PGFE)., Results: In 29 out of 34 infections the initial strains was susceptible. In 11 cases, the culture were not negativized in spite of their susceptible pattern. In 4 cases there was derepression during therapy. In 5 cases the initial strains were derepressed. The microorganisms isolated more frequently were Pseudomonas aeruginosa (22 cases) and Enterobacter cloacae (5 cases). The beta-lactamase activity detected correspond well with a betaLac-ind. In those cases with derepression during therapy, the initial susceptible strain and the resistant strain were identical by PGFE.