Multiresistant Gram Research Articles

Antimicrobianos en Unidades de Cuidados Intensivos: Uso empírico

Infections are a main cause of mortality in the Intensive Care Units. At the present moment in Chile there is a predominance of Gram positive species (methicillin resistant Staphylococcus aureus, coagulase negative Staphylococci and vancomycin resistant Enterococcus) and multiresistant Gram negative rods (Klebsiella pneumoniae). A late or incorrect prescription of antibiotics enhances significantly the mortality of these infectious episodes. The introduction of automated blood culture and of rapid identification methods allows the indication of broad spectrum antimicrobial agents as initial empirical prescription making adequate and prompt adjustments for each patient. We summarize the advantages and limitations of new drugs potencially active against these multiresistant isolates: cefepime, carbapenems, the new quinolones, pristinamycin, teicoplanin and linezolid. The prescription of antibiotics must be based in the local epidemiology of nosocomial infections and its pattern of resistance.

Current approaches to screening for Multi-resistant Organisms (MRO) in acute care Australian and selected New Zealand hospitals and recommendations for a minimum standard

This article provides information regarding current screening practices. Draft recommendations have been compiled to foster debate regarding a national approach to multi-resistant organisms (MRO) screening in acute care Australian and New Zealand hospitals. There is no consensus internationally as to the best manner in which to conduct screening for MROs. The AICA National Advisory Board decided that to facilitate a consensus approach towards MRO screening, it was useful to describe current screening practices in detail.Hospital infection control practitioners and microbiologists were invited to respond to a survey questionnaire distributed bye-mail to infection control, infectious diseases and microbiology specialists with involvement in infection control. In order to improve response rates, where necessary, individuals in each state were approached directly.Surveys were completed by representatives from a majority of large public hospitals and a significant number of private and district hospitals. There was wide variation in practice in Australian hospitals with regard to screening of patients for MROs. The approaches (clinical and microbiological) taken in different hospital settings, different clinical services and to each of the different MROs - MRSA, VRE and multi-resistant Gram negatives (MRGN) - are described. Approaches to ‘clearing’ previously colonised patients are also described.

Colistin in the treatment of infections from multiresistant Gram (-) bacilli

Colistin in the treatment of infections from multiresistant Gram (-) bacilli

Antibiotic resistance in postoperative infections.

Postoperative infections at the site of an operation often have serious consequences. This is particularly true of postoperative intra-abdominal infections, in which the identified organisms are typically multiresistant Gram negatives, Gram positives, and yeast. There is considerable evidence that the adequacy of empiric therapy will have substantial impact on the outcome. Current recommendations for such therapy are reviewed.

A Conserved Residue at the Extreme C-Terminus of FtsZ Is Critical for the FtsA-FtsZ Interaction in Staphylococcus aureus

FtsZ, a tubulin-like protein with GTPase activity, and FtsA, an actin-like protein with ATPase activity, are two proteins known to play critical roles in the later stages of the bacterial cell cycle. It is well documented that FtsA-FtsZ co-localization at the septum of dividing bacteria is essential for successful cell division in E. coli. We have validated and characterized this interaction by co-expressing FtsA and FtsZ, from both E. coli and S. aureus, in the yeast two-hybrid system. We demonstrate for the first time a specific association between S. aureus FtsA and FtsZ proteins and self interaction of S. aureus FtsZ. These observations are consistent with the conserved role of FtsA and FtsZ in bacterial cell division. Using deletion mutagenesis, we have shown that a highly conserved motif as small as 10 residues in the extreme C-terminus of S. aureus FtsZ is critical for the interaction with FtsA. Further dissection of this motif by alanine scanning mutagenesis showed that Phe376 likely plays a major role in the FtsA-FtsZ interaction. This work has important implications for the design of antagonists and agonists of the FtsA-FtsZ interaction as such agents could provide a novel approach for tackling multi-resistant Gram positive pathogens.

The In Vitro and In Vivo Activity of Ciprofloxacin

DOI: http://dx.doi.org/10.5915/21-1-5517 The third generation quinolones represent a new development and a possible alternative to the more conventional B-lactam and aminoglycosides for the management of difficult nosocomial infections. This study compared the in vitro and in vivo antibacterial activity of ciprofloxacin, a new fluroquinolone. The in vitro antibacterial activity of ciprofloxacin was compared with three quinolones, three aminoglycosides and three cephalosporins against 500 clinical isolates, including 100 gentamicin and 30 nalidixic acid resistant gram negative organisms. The latter were also tested against amifloxacin, ofloxacin and enoxacin. Minimum inhibitory concentration (MICs) were performed by agar dilution method using a final inoculum of 10 4 colony forming units (CFU)/ml. The results showed that ciprofloxacin was the most active drug against aerobic gram negative bacteria. Aminoglycoside and cephalosporin resistance did not affect the MIC 90, however resistance to nalidixic acid showed a four fold increase in MIC 90 of all the quinolones. The efficiency and safety of ciprofloxacin was determined in an open prospective study in 57 hospitalized patients with injections caused by multi-resistant gram-negative bacteria. A variable dosage was used, dependent on the site of infection. Clinical and bacteriological success occurred in 49 patients which included 12 bacteremias. Eight patients were classed as failures; although clinical improvement occurred, the organisms persisted to the end of therapy. Persistence was associated with presence of prostheses. Two patients had minor side effects. We conclude that ciprofloxacin has good in vitro and in vivo activity against a wide range of aerobes including multi-resistant gram negative bacteria.

Aztreonam: The First Monobactam

There are several areas in which the use of aztreonam seems logical. Infections caused by organisms sensitive to aztreonam that are known to be multiresistant to other agents can be treated directly with aztreonam in single, directed therapy, thus making the use of more toxic agents unnecessary. In types of infection in which both gram positive and gram negative bacteria are present, aztreonam can replace the usual aminoglycoside component of the therapeutic regimen. In settings of mixed infections suspected of being caused by drug-resistant strains of Enterobacteriaceae and/or P. aeruginosa, aztreonam can be combined with an agent active against gram positive organisms or with one active against anaerobes. Aztreonam has proven to be effective, safe therapy for serious and life-threatening infections caused by multiresistant aerobic gram negative bacteria. It should be used in combination with drugs that inhibit gram positive species if the etiology of the infection is not known, particularly in the immunocompromised, neutropenic patient. Doses of 1 g every 8 to 12 hours will be adequate for treatment of infections caused by most Enterobacteriaceae. Whether 2 g doses every 8 hours would be preferred for treatment of systemic Pseudomonas infections remains to be determined. Urinary infections caused by gram negative bacteria can be treated with 500 mg administered IM once or twice daily. The dosage of aztreonam should be adjusted in patients with renal failure. Clearly, aztreonam is a useful addition to the antimicrobial agents available to the physician.

Aztreonam: The First Monobactam

There are several areas in which the use of aztreonam seems logical. Infections caused by organisms sensitive to aztreonam that are known to be multiresistant to other agents can be treated directly with aztreonam in single, directed therapy, thus making the use of more toxic agents unnecessary. In types of infection in which both gram positive and gram negative bacteria are present, aztreonam can replace the usual aminoglycoside component of the therapeutic regimen. In settings of mixed infections suspected of being caused by drug-resistant strains of Enterobacteriaceae and/or P. aeruginosa, aztreonam can be combined with an agent active against gram positive organisms or with one active against anaerobes. Aztreonam has proven to be effective, safe therapy for serious and life-threatening infections caused by multiresistant aerobic gram negative bacteria. It should be used in combination with drugs that inhibit gram positive species if the etiology of the infection is not known, particularly in the immunocompromised, neutropenic patient. Doses of 1 g every 8 to 12 hours will be adequate for treatment of infections caused by most Enterobacteriaceae. Whether 2 g doses every 8 hours would be preferred for treatment of systemic Pseudomonas infections remains to be determined. Urinary infections caused by gram negative bacteria can be treated with 500 mg administered IM once or twice daily. The dosage of aztreonam should be adjusted in patients with renal failure. Clearly, aztreonam is a useful addition to the antimicrobial agents available to the physician.