Multicentre investigation of carbapenemase-producing Escherichia coli and Klebsiella pneumoniae in German hospitals.

Aim of this study was to determine the incidence and molecular epidemiology of carbapenemase-producing Escherichia coli and Klebsiella pneumoniae in Germany. E. coli and K. pneumoniae isolates from clinical samples which were non-susceptible to carbapenems were collected in laboratories serving 20 hospitals throughout Germany from November 2013 to April 2014. The isolates were tested for the presence of carbapenemases by PCR and phenotypic methods and typed by multilocus sequence typing. Risk factors including a previous hospitalization abroad were analysed. Carbapenemases were detected in 24 isolates from 22 patients out of 464,514 admissions. Carbapenemases included OXA-48 (n=14), KPC-2 (n=8) and NDM-1 (n=2). Except for two K. pneumoniae isolates with ST101, all OXA-48 producing strains belonged to different clones. In contrast, half of KPC-2 producing K. pneumoniae were of ST258 and both NDM-1 producing strains were of ST11. Compared to carbapenem-susceptible controls, patients with carbapenemase-producing strains differed by a significantly higher proportion of males, a higher proportion of isolates from wound samples and a more frequent previous stay abroad in univariate analysis. This multicentre study demonstrated an incidence of carbapenemase-producing E. coli and K. pneumoniae from clinical samples in Germany of 0.047 cases per 1000 admissions. OXA-48 was more frequent than KPC-2 and NDM-1 and showed a multiclonal background.

Emergence of OXA-48-type carbapenemase-producing Enterobacteriaceae in German hospitals.

Nine carbapenem-resistant Enterobacteriaceae isolates collected from eight patients in five German hospitals were investigated. Six isolates produced the OXA-48 carbapenemase, and three isolates produced OXA-162, which is a point mutant form of OXA-48. Both carbapenemase genes were located on IncL/M-type conjugative plasmids. Insertion sequence IS1999 (truncated or not by IS1R) was located upstream of the bla(OXA-48) and bla(OXA-162) genes in all of the isolates. Pulsed-field gel electrophoresis typing indicated the clonal transmission of an OXA-48-producing Klebsiella pneumoniae strain in two hospitals.

Validation of the Microbiological Testing of Tissue Preparations Using the BACTEC™ Blood Culture System.

BACKGROUND: Since blood culture bottles are validated by the manufacturer for blood only, an additional validation for the use with fluids of tissue preparations is necessary. METHODS: Two 10-ml samples of cornea culture medium, histidine-tryptophan-ketoglutarate (HTK) solution, or Ringer solution at the end of femur head thermo-disinfection were given into blood culture bottles (BD BACTEC™ Plus Aerobic/F, Anaerobic/F for cornea culture medium and BD BACTEC™ Standard Aerobic/Anaerobic for HTK and Ringer solution) and subsequently spiked with 10-100 colony forming units (CFU) of bacteria or fungi (aerobic bacteria: Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa; anaerobic bacteria: Clostridium sporogenes; fungi: Candida albicans, Aspergillus brasiliensis) according to the European Pharmacopoeia Chapter 2.6.1. RESULTS: All tested bacteria and fungi could be detected in all solutions. All positive and negative controls were tested correctly. Compared to the positive controls, the microbial growth was delayed in the antibiotic-containing cornea culture medium, and negative in two cases of B. subtilis spiking. CONCLUSION: The use of BACTEC™ blood culture bottles seems to be a suitable method for microbiological testing of HTK solution, Ringer solution, and, with limitations, also for testing of the antibiotic-containing cornea culture medium.

Intraabdominal bacterial infections significantly alter regeneration and function of the liver in a rat model of major hepatectomy.

BACKGROUND: No systematic investigations of interactions of postoperative infections and liver regeneration after resection are available. MATERIALS AND METHODS: Male Sprague-Dawley rats underwent sham operation, 70% partial hepatectomy (PH), cecal ligation and puncture (CLP), or synchronous PH + CLP and were killed at regular intervals. Liver regeneration and function were measured by the mitotic index, Bromo-deoxy-uridine labeling, and Ki-67 as well as bilirubin, albumin, and indocyanine green plasma disappearance rate. The inflammatory response was evaluated by determination of IL-1beta and myeloperoxidase (MPO) activity. Bacterial concentrations in different organs were quantified. RESULTS: Simultaneous CLP + PH resulted in a significantly delayed regeneration kinetic, which was most pronounced at 24 h. This was preceded by hyperinflammation with increased liberation of pro-inflammatory cytokines in the PH + CLP group at 6 h. After 48 h, the pro-inflammatory response declined, and regeneration proceeded also in the PH + CLP group. Liver function was found impaired in both groups; however, it was significantly worse in the PH + CLP group. Especially after 48 h, when regeneration peaked in this group, liver function significantly declined. At 96 h, only minor differences were seen, but the persistently elevated proliferative activity indicated the delay of regeneration after PH + CLP. CONCLUSION: The present analysis shows that infectious conditions delay liver regeneration. Our data suggest a cross-linkage of both conditions via the functional liver capacity. A direct role of microorganisms seems unlikely; however, the inhibitory effect of the pro-inflammatory cytokines may be involved.

How many infections are caused by patient-to-patient transmission in intensive care units?

OBJECTIVE: The proportion of intensive care unit (ICU)-acquired infections that are a consequence of nosocomial cross-transmission between patients in tertiary ICUs is unknown. Such information would be useful for the implementation of appropriate infection control measures. DESIGN: A prospective cohort study during 18 months. SETTING: Five ICUs from two university hospitals. PATIENTS: All patients admitted for >/=48 hrs. MEASUREMENT: ICU-acquired infections were ascertained during daily bedside patient and chart reviews. Episodes of potential cross-transmission were identified by highly discriminating genetic typing of all clinical and surveillance isolates of the ten bacterial species most frequently associated with nosocomial infections in ICUs. Isolation of indistinguishable isolates in two or more patients defined potential transmission episodes. MAIN RESULTS: During 28,498 patient days, 431 ICU-acquired infections and 141 episodes of nosocomial transmissions were identified. A total of 278 infections were caused by the ten species that were genotyped, and 41 of these (14.5%) could be associated with transmissions between patients. CONCLUSION: Infections acquired during treatment in modern tertiary ICUs are common, but a causative role of direct patient-to-patient transmission can only be ascertained for a minority of these infections on the basis of routine microbiological investigations.

Supply of pre- and probiotics reduces bacterial infection rates after liver transplantation--a randomized, double-blind trial.

Bacterial infections frequently occur early after liver transplantation. We recently reported significant progress with a synbiotic composition, consisting of one lactic acid bacteria (LAB) and one fiber, which reduced the infection rate from 48% (with selective bowel decontamination) to 13%. Now, our aim is to study if a combination of different LAB and fibers would further improve outcome. A prospective randomized double-blind trial was undertaken in 66 liver transplant recipients. All patients received enteral nutrition immediately post-operatively. Comparison was made between one group (A) receiving a composition of four LAB and four fibers and another group (B) receiving the fibers only. The treatment started the day before surgery and continued for 14 days. Thirty-day infection rate, length of hospital stay, duration of antibiotic therapy, non-infectious complications and side effects of enteral nutrition were recorded. The incidence of post-operative bacterial infections was significantly reduced; being 48% with only fibers and 3% with LAB and fibers. In addition, the duration of antibiotic therapy was significantly shorter in the latter group. In both groups, mainly mild or moderate infections occurred. Fibers and LAB were well tolerated. Early enteral nutrition supplemented with a mixture of LAB and fibers reduces bacterial infection rates following liver transplantation. Treatment with only fibers led to a low incidence of severe infections.

In situ antimicrobial effectiveness of chlorhexidine and calcium hydroxide: gel and paste versus gutta-percha points.

The aim of this study was to determine the antibacterial effectiveness of either chlorhexidine or calcium hydroxide integrated in gutta-percha points compared with chlorhexidine or calcium hydroxide delivered as gel or paste, respectively. A total of 70 initially sterile roots with open accesses were carried for 1 week in the oral cavities of two volunteers. The roots were then removed, and samples were taken from the root canals for microbial analysis. The roots were medicated with calcium hydroxide paste, 5% chlorhexidine gel, or a chlorhexidine- or calcium hydroxide-containing gutta-percha point. The accesses were closed with bonding material, and the roots incubated for 1 week. After removal of the antimicrobial agents, roots were again checked for bacterial growth. One thioglycolate-soaked paper point was then introduced into each canal, and roots were incubated for 1 week more to observe bacterial regrowth. After 1 week of medication, the absolute bacterial count revealed significant differences compared with the controls. However, only the chlorhexidine-gel and the calcium hydroxide paste group showed no microbial colonization in a considerable number of samples after 1 and 2 weeks.