Community-acquired methicillin-resistant invasive infections: a case series from Central-South Chile.

The emergence of community-acquired methicillin-resistant (CA-MRSA) infections at the end of the 20th century represents a significant shift in the epidemiology of staphylococcal infections and, consequently, their clinical management. There are diverse CA-MRSA clones that are widely spread worldwide, showing differences in their regional dissemination, which has been dynamically changing over time. Although the first CA-MRSA description occurred about 30 years ago, its epidemiology in certain regions, such as South America, has been poorly explored, resulting in a gap in the understanding of the epidemiology of CA-MRSA in under-represented countries/regions.

[Molecular basis of methicillin-resistance in Staphylococcus aureus].

Staphylococcus aureus isolates resistant to several antimicrobials have been gradually emerged since the beginning of the antibiotic era. Consequently, the first isolation of methicillin-resistant S. aureus occurred in 1960, which was described a few years later in Chile.

[Monoarticular tuberculosis of the wrist: a case report].

Monoarticular tuberculosis of the wrist is a rare presentation of primary tuberculosis, being more common skeletal forms involving the spine. Extraspinal tuberculous osteomyelitis is rare and comprises only 2 to 3% of all cases of osteoarticular Mycobacterium tuberculosis infections. We present a case of a 49 years old female patient, who worked as an hospital cleaning employed without other comorbidity.

[Colistin in the post-antibiotic era].

One of the most important features of the post-antibiotic era in the late 20th century is the resurgence of colistin for the treatment of extensively drug resistant gram-negative bacteria (XDR). Colistin is a narrow spectrum anti-biotic, active against microorganisms with clinical significance such as Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae. Nowadays its toxicity is lower, partly explained by better pharmaceuticals and management of the critically ill patients.

[Isolation of Staphylococcus aureus hetero-resistant to vancomycin (hVISA) in the Regional Hospital of Concepción, Chile].

Methicillin-resistant Staphylococcus aureus (MRSA) is widely distributed in hospital environments, causing serious infections, mainly the bloodstream, surgical site infection and pneumonia. Vancomycin (VAN) is the antibiotic of choice for treating severe MRSA infections; however, nowadays worldwide resistant strains (VRSA), with intermediate susceptibility (VISA) and decreased susceptibility or hetero-resistance to VAN (hVISA) have been reported, related to treatment failure and increased mortality. This report describes the first confirmed isolation of MRSA with hVISA phenotype in a public hospital in Chile.

[The pneumococcal connection].

The resistance of gram-negative bacilli is one of the most important areas in modern medicine, however it hasn't been highlighted the role of the third generation cephalosporins and in particularly ceftriaxone in the selection of gram-negative bacilli resistant to these agents. Paradoxically, ceftriaxone, like the rest of the molecules of this generation, whose initial indication were gram- negative infections began to be used as an agent of choice in pneumococcal infections. The broad spectrum activity of this molecule with its favorable pharmacokinetic properties replaces other agents by this antibiotic in the treatment of a wide range of community acquired infections.

[Copper activity against multiresistant Gram negative bacilli isolated from Chilean hospitals].

Introduction: Multiresistant nosocomial pathogens, especially Gram-negative bacilli (GNB), are a serious problem for public health systems worldwide. Due to their antimicrobial properties, copper alloys have been suggested as an alternative for the control of bacterial burden in surfaces in hospital environment. However, antibiotic multiresistance and copper resistance could be associated in GNB, and there is evidence that both kind of resistance genes (antibiotic and copper) can be located on the same genetic structures.

[Evolution of use of antibiotics of restricted prescription and trend of bacterial susceptibility in Concepcion Regional Hospital, Chile].

The aim of this study was analyze the use of restricted antibiotics by patients hospitalized between 2004 and 2008 in Guillermo Grant Benavente Hospital in Concepcion. Also we attempted to identify possible correlations between antibiotic consumption and patterns of bacterial susceptibility. We performed a retrospective observational study that quantified the use of restricted antibiotics using DDD/100-bed-days, and cumulative susceptibility reports informed by the hospital's microbiology laboratory for bacterial susceptibility.

[Multi-drug efflux pumps and antibiotic resistance in Acinetobacter baumannii].

Bacterial multi-drugs systems contribute to the development of multi-resistance patterns of Acinetobacter baumannii, a nosocomial pathogen of increasing importance due to its emerging resistance to carbapenems. The multi-resistance phenomena is generated by a combination of mechanisms, one of which the efflux pump system. Many of these multiresistant isolates of A.

[Molecular identification of aminoglycoside-modifying enzymes among strains of Enterococcus spp. isolated in hospitals of the VIII Region of Chile].

Background: Infectious diseases produced by Enterococcus spp, must be treated with a synergistic combination between a penicillin and an aminoglycoside. High level resistance to aminoglycosides is a serious therapeutic problem, since it predicts the loss of synergistic activity of this antimicrobial combination.

Aim: To investigate the presence of genes encoding aminoglycoside-modifying enzymes (AMEs) among strains of Enterococcus spp with high level of resistance to aminoglycosides.

[Resistance to gentamicin, amikacin and ciprofloxacin among nosocomial isolates of klebsiella pneumoniae subspecie pneumoniae producing extended spectrum beta-lactamases].

Background: Klebsiella pneumoniae is a pathogenic bacterium frequently isolated from nosocomial samples, specially the subspecie pneunonlae, with extensive antibiolic resistance profiles, including third generation cepbhalosporiis, aminoglycosides and quinolones. This is specially true for those strains producing extended spectrum beta lactamases (ESBL).

Aim: To investigate the susceptibility to gentamicin, amikacin and ciprofloxacin and the presence of some aminogloycoside modifying enzyme (AMEs) among nosocomial strains of K pneumoniae subspecie pneumoniae producing ESBL.

[Integrons and resistance gene cassettes: structure and role against antimicrobials].

Bacteria have developed sophisticated and successful genetic mechanisms to evade the action of antimicrobials. Bacterial multiresistance has caused serious problems in the treatment of nosocomial infections. Integrons and gene cassettes are considered the main genetic elements in the evolution of plasmids and transposons that actively participate in the mobilization of genes, codifying different bacterial resistance mechanisms.

[Integrons and antimicrobial resistance gene cassettes in Shigella flexneri strains ].

Background: The resistance of Shigella flexneri to antimicrobial agents can be associated to the presence of integrons that may contain and express antimicrobial resistance gene cassettes.

Aim: To study antimicrobial resistance and the presence of integrons and antimicrobial gene cassettes in Shigella flexneri strains.

Material And Methods: In vitro susceptibility to 27 antimicrobials was studied in twenty four Shigella flexneri strains isolated from stools.

[Classic and molecular methodologies for the identification of Enterococcus species].

Background: Enterococcus is a bacterial genus with low virulence. However, in the last years, the importance of some enterococcus species as nosocomial pathogens has increased, specially due to their resistance to some antimicrobial.

Aim: To identify enterococcus strains using classical biochemical techniques and genomic amplification with Polymerase Chain Reaction (PCR).