Effects of hyperosmolar agents--lactulose, lactitol, sodium phosphate and polyethylene glycol--on cecal coliform bacteria during traditional bowel cleansing: an experimental study in rats.

Mechanical bowel cleansing is considered to be necessary prior to colorectal surgery, some radiological or endoscopic procedures, and for fecal disimpaction. Traditional bowel cleansing (TBC) with cathartics and enemas is a method of mechanical bowel cleansing for patients who have restrictive factors for whole-bowel irrigation (WBI), such as excessive fecal impaction, cardiac, hepatic or renal disorders. In this experimental study, TBC with hyperosmolar agents was evaluated in terms of their effects on colonic flora and bacterial translocation (BT). Sprague-Dawley rats were divided into 6 groups. The animals, except controls, were not fed for 72 h but received tap water ad libitum. During this period, lactulose, lactitol, sodium phosphate (NaP), polyethylene glycol 3350 (PEG3350) and physiological saline gavages were administered to the rats in groups 1-5, respectively, once a day. All animals except controls (group 6) received enemas with 15 ml of warm saline twice a day. The cecum, mesenteric lymph nodes (MLNs) and portal vein blood were sampled for microbiological and histopathological analysis. The highest level of coliform bacterial overgrowth and BT to MLNs were observed in the lactulose group, although the others, except the saline and control groups, also caused some degree of BT. Portal vein cultures were negative for all groups. Histopathological damage was not associated with cecal bacterial count and BT. As a result of this study, PEG3350 seems to be safer and more effective than lactulose, lactitol and NaP during TBC.

Synergistic effect of cefepime on the phagocytic killing of Staphylococcus aureus by human polymorphonuclear leucocytes and the determination of this effect by means of nitrite production.

In this study the effect of cefepime on the phagocytosis and intracellular killing of Staphylococcus aureus by human polymorphonuclear leucocytes (PMNL) was determined. The opsonophagocytic killing of S. aureus was synergistically enhanced by cefepime at concentrations below 0.5 times the minimal inhibitory concentration (MIC), and four times the MIC at higher concentrations. The effect of cefepime on phagocytosis and the bactericidal activity of PMNL was also investigated by the measurement of nitrite levels using a Sievers analyser. According to the nitrite levels, cefepime enhanced not only the phagocytosis by PMNL 2.1-fold in the 0.5 MIC and 2.8-fold in the four MIC values but also the bactericidal activity of neutrophils 2.5-fold in the 0.5 MIC and 2.8-fold in the four MIC values, respectively. The beneficial cefepime-leucocyte interaction may explain the efficacy of cefepime against intracellular pathogens.

Prevalence of high level aminoglycoside and vancomycin resistance among enterococci in Turkey.

Enterococcus spp. have become the third most common cause of nosocomial infections. High-level aminoglycoside resistance (HLAR), an important clinical concern, has been associated with some species of enterococci. The synergistic effect obtained by the combination of aminoglycosides with penicillin or vancomycin disappears in strains that show high-level resistance (HLR) to the aminoglycosides. We evaluated the agar dilution and high content disk diffusion tests for the detection of HLAR for 60 isolated enterococci. In our study 4 strains of Enterococcus faecalis (6.6%) and 8 strains of Enterococcus faecium (13.3%), totally 20% were found to be highly resistant to gentamicin; 2 strains of E. faecalis (13.3%), 8 strains of E. faecium (3.3%), totally 16.6% showed HLR to streptomycin by agar dilution method and the same rates were found by high-content disk diffusion method. 2 strains of E. faecalis (3.3%), 4 strains of E. faecium (6.6%), totally 10% showed vancomycin resistance by agar dilution method. The ratio for beta lactamase activity was found to be 26.6% for E. faecalis and 3.3% for E. faecium. Our results demonstrate that high-content disk diffusion test should be performed by using both gentamicin and streptomycin in routine screening of HLAR among enterococci and the determination of beta lactamase activity at the same time is also useful for detecting resistance to a beta lactam agent.