Antimicrobial susceptibility profiles of anaerobic bacteria, isolated from human clinical specimens, within different European and surrounding countries. A joint ESGAI study.

OBJECTIVES: Studies on the antimicrobial susceptibility profile of anaerobic bacteria are underrepresented in the literature. Within this study we aim to give an extensive overview of the differences in antimicrobial susceptibility profiles between different European and surrounding countries. METHODS: Minimal inhibitory concentration (MIC) data of different antibiotics were collected from 10 participating laboratories, representing an equal number of countries. All MIC's were determined using Etest, according to the protocol used by the participating laboratory. Anaerobic genera represented by at least 10 clinical isolates were included in the study. RESULTS: Each country tested different antibiotics, sometimes depending on the kind of infection and/or the anaerobic species isolated. All countries tested clindamycin and metronidazole. Resistance rates differed remarkably between the different countries. Especially in Kuwait, resistance was high for all tested antibiotics. Unexpected metronidazole resistance was observed for Finegoldia magna isolates, Peptoniphilus isolates and Eggerthella lenta isolates. CONCLUSIONS: Due to the extensive differences in antimicrobial susceptibility profile of anaerobic bacteria isolated within different countries, we strongly recommend to perform this kind of study on a regular basis.

Review of the prevalence and drug resistance of tuberculosis in prisons: a hidden epidemic.

SUMMARY The prison setting has been often cited as a possible reservoir of tuberculosis (TB) including multidrug-resistant (MDR)-TB. This is particularly true in low-income, high TB prevalence countries in Sub-Saharan Africa. A systemic literature review was done to assess the prevalence, drug resistance and risk factors for acquiring TB in the prison population. Our review indicated a high prevalence of TB in prisons which is reported to be 3- to 1000-fold higher than that found in the civilian population, indicating evidence and the need for public health policy formulation. In addition, high levels of MDR and extensively drug-resistant (XDR)-TB have been reported from prisons, which is a warning call to review prison TB control strategy. Multiple risk factors such as overcrowding, poor ventilation, malnutrition, human immunodeficiency virus (HIV), and others have fuelled the spread of TB in prisons. Furthermore, the impact extends beyond the prison walls; it affects the civilian population, because family visits, prison staff, and members of the judiciary system could be potential portals of exit for TB transmission. The health of prisoners is a neglected political and scientific issue. Within these background conditions, it is suggested that political leaders and scientific communities should work together and give special attention to the control of TB and MDR-TB in prisons. If not, TB in prisons will remain a neglected global problem and threatens national and international TB control programmes. Further researches are required on the prevalence and drug resistance of smear-negative TB in prisons. In addition, evidence of the circulating strains and transmission dynamics inside prisons is also warranted.

[Clinical impact of infections with carbapenem-resistant enterobacteriaceae in liver transplant recipients]. / Klinische Bedeutung von Infektionen durch Carbapenem-resistente Enterobakterien bei Lebertransplantierten.

Infections with carbapenem-resistant Enterobacteriaceae (CRE) are an emerging cause of morbidity and mortality among liver transplant recipients (LTR) worldwide, particularly Klebsiella pneumoniae carbapenemase (KPC)-producing organisms. Approximately 3 - 13 % of solid organ transplant recipients in CRE-endemic areas develop CRE infections, and the infection site correlates with the transplanted organ. The cumulative 30-day mortality rate of LTR infected with carbapenem-resistant K. pneumoniae is 36 %, and the 180-day mortality rate is 58 %. Awareness of the high vulnerability of LTR to fatal bacterial infection leads to the more frequent use of ultrabroad-spectrum empirical antibiotic therapy, which further contributes to the selection of extreme drug resistance. Moreover, it comprises a relevant risk of failure to initiate adequate empirical treatment due to the fact that culture-based techniques used to identify CRE imply a 48- to 72-hour delay from blood culture collection until administration of the targeted therapy. This vicious circle is difficult to avoid and leads to increased clinical intricacy and narrowed antimicrobial therapeutic options. Because available options are extremely limited, infection prevention measures have gained outstanding importance, particularly in the phase after liver transplant requiring intense immunosuppression early on. Improving clinical outcomes is a major challenge and involves a multi-targeted approach combining strictly applied hygiene measures, active surveillance tests, the use of modern, time-saving methods of molecular biology, and enforced antibiotic stewardship. This article reviews the current literature regarding the incidence and outcome of CRE infections in LTR, and it summarises current preventive and therapeutic recommendations to minimise the threat by CRE in real-life clinical transplant settings.

Colonization of liver transplant recipients with KPC-producing Klebsiella pneumoniae is associated with high infection rates and excess mortality: a case-control analysis.

PURPOSE: From mid-2010 to early 2013 there was a large single-center (Leipzig University Hospital, Germany) outbreak of Klebsiella pneumoniae carbapenemase (KPC) type 2 producing K. pneumoniae (KPC-2-KP) involving a total of 103 patients. The aim of this study was to compare KPC-positive liver transplant recipients (LTR) and KPC-negative controls to determine both the relative risk of infection following colonization with KPC-2-KP and the case fatality rate associated with KPC-2-KP. METHODS: The study cohort of this retrospective observational study comprised nine patients who had undergone orthotopic liver transplantation (LTx) (median age of 52 years, range 28-73 years) with confirmed evidence of colonization with KPC-2-KP. The data from these nine LTR were matched to 18 LTR (1:2) in whom carbapenem-resistant pathogens were not present and compared for clinical outcomes. RESULTS: Of these nine cases, eight (89 %) progressed to infection due to KPC-2-KP, and five (56 %) were confirmed to have bloodstream infection with KPC-2-KP. Matched-pair analysis of KPC-positive LTR and KPC-negative controls revealed a substantially increased relative risk of 7.0 (95 % confidence interval 1.8-27.1) for fatal infection with KPC-2-producing K. pneumoniae after transplantation with a mortality rate of 78 % (vs. 11 %, p = 0.001). CONCLUSIONS: Colonization with KPC-2-KP in LTR leads to high infection rates and excess mortality. Therefore, frequent screening for carbapenem-resistant bacteria in patients on LTx waiting lists appears to be mandatory in an outbreak setting. Patients with evidence of persistent colonization with KPC-producing pathogens should be evaluated with extreme caution for LTx.

Invasive cardiac aspergillosis after orthotopic liver transplantation.

Invasive aspergillus infection occurs in 5 - 42 % of liver-transplanted recipients and is a dangerous complication, associated with high mortality if untreated. However, the early diagnosis of invasive aspergillosis can be elusive, as clinical signs are unspecific and the pathogenic agent is difficult to demonstrate. We here report about a 58-year-old man with acute liver failure caused by newly diagnosed chronic hepatitis B infection who underwent liver transplantation. The postoperative course was uneventful, and the patient was discharged after 30 days. After 105 days the patient was readmitted because of fever, recurrent chest and abdominal pain. Computed tomography revealed a cardiac lesion; other diagnostic steps including bone-marrow and endomycordial biopsy, virological and microbiological investigations gave no clear findings. To exclude a malignant process, thoracotomy with mass and simultaneous lower left lobe resection were performed. Histopathological findings revealed an invasive perimyocardial aspergillosis. Immediate intravenous therapy with voriconazole and caspofungin was initiated and monitoring of the mass was performed with transesophageal echocardiography and Cardio-MRI. Due to slightly increase of the lesion, medication was switched to posaconazole and caspofungin. Under this dual fungal treatment the lesion regressed and the patient could be discharged after two months in good clinical condition. Frequent Cardio-MRI scan after discharge showed further mass-regression. Therefore antifungal treatment was switched to oral posaconazole mono-therapy. After one year, complete reduction of the mass was achieved and antifungal therapy was discontinued. Recent diagnostic imaging follow-up showed no pathological finding.

Results from the ARTEMIS DISK Global Antifungal Surveillance Study, 1997 to 2007: a 10.5-year analysis of susceptibilities of Candida Species to fluconazole and voriconazole as determined by CLSI standardized disk diffusion.

Fluconazole in vitro susceptibility test results for 256,882 isolates of Candida spp. were collected from 142 sites in 41 countries from June 1997 to December 2007. Data were collected for 197,619 isolates tested with voriconazole from 2001 to 2007. A total of 31 different species of Candida were isolated. Increased rates of isolation of the common non-albicans species C. glabrata (10.2% to 11.7%), C. tropicalis (5.4% to 8.0%), and C. parapsilosis (4.8% to 5.6%) were noted when the time periods 1997 to 2000 and 2005 to 2007 were compared. Investigators tested clinical isolates of Candida spp. by the CLSI M44-A disk diffusion method. Overall, 90.2% of Candida isolates tested were susceptible (S) to fluconazole; however, 13 of 31 species identified exhibited decreased susceptibility (<75% S), similar to that seen with the resistant (R) species C. glabrata and C. krusei. Among 197,619 isolates of Candida spp. tested against voriconazole, 95.0% were S and 3% were R. About 30% of fluconazole-R isolates of C. albicans, C. glabrata, C. tropicalis, C. rugosa, C. lipolytica, C. pelliculosa, C. apicola, C. haemulonii, C. humicola, C. lambica, and C. ciferrii remained S to voriconazole. An increase in fluconazole resistance over time was seen with C. parapsilosis, C. guilliermondii, C. lusitaniae, C. sake, and C. pelliculosa. Among the emerging fluconazole-R species were C. guilliermondii (11.4% R), C. inconspicua (53.2% R), C. rugosa (41.8% R), and C. norvegensis (40.7% R). The rates of isolation of C. rugosa, C. inconspicua, and C. norvegensis increased by 5- to 10-fold over the 10.5-year study period. C. guilliermondii and C. rugosa were most prominent in Latin America, whereas C. inconspicua and C. norvegensis were most common in Eastern European countries. This survey identifies several less-common species of Candida with decreased susceptibility to azoles. These organisms may pose a future threat to optimal antifungal therapy and underscore the importance of prompt and accurate species identification and antifungal susceptibility testing.

A real-time PCR assay for the differentiation of Candida species.

AIMS: We established a real-time PCR assay for the detection and strain identification of Candida species and demonstrated the ability to differentiate between Candida albicans the most common species, and also Candida parapsilosis, Candida glabrata, Candida tropicalis and Candida dubliniensis by LightCycler PCR and melting curve analysis. METHODS AND RESULTS: The DNA isolation from cultures and serum was established using the QIAmp Tissue Kit. The sensitivity of the assay was ≥ 2 genome equivalents/assay. It was possible to differentiate all investigated Candida species by melting curve analysis, and no cross-reaction to human DNA or Aspergillus species could be observed. CONCLUSIONS: The established real-time PCR assay is a useful tool for the rapid identification of Candida species and a base technology for more complex PCR assays. SIGNIFICANCE AND IMPACT OF THE STUDY: We carried out initial steps in validation of a PCR assay for the detection and differentiation of medically relevant Candida species. The PCR was improved by generating PCR standards, additional generation of melting curves for species identification and the possibility to investigate different specimens simultaneously.

[Tuberculosis and travelling]. / Tuberkulose und Reisen.

Tuberculosis (TB) in Germany in the year 2007 with 5020 reported cases (incidence: 6.1 newly diagnosed cases per 100 000 inhabitants) was continuously in decline. 43.1 % of these persons were from countries with a higher TB incidence as compared to Germany. However, not only migration but also personal journeys from low- to high-incidence countries carries an increased risk of infection with M. tuberculosis (MTB). An early active TB follows only rarely, more common, however, is a latent TB infection (LTBI). Not only the active form of TB but also LTBI, with a potential for reactivation years or decades later, can be of enormous relevance for the individual and the social environment. The early detection of an MTB infection and its possible sequelae are decisive for a continued successful battle against tuberculous diseases, especially in view of increasing travel activities.

Comparative analysis of antimicrobial susceptibility among organisms from France, Germany, Italy, Spain and the UK as part of the tigecycline evaluation and surveillance trial.

As part of the tigecycline evaluation and surveillance trial (TEST), bacterial isolates were collected from 39 centres in France, Germany, Italy, Spain and the UK between January 2004 and August 2006. Antimicrobial susceptibilities were determined according to CLSI guidelines. Italy had the highest rate of methicillin-resistant Staphylococcus aureus (36.4%), and was the only country to report vancomycin-resistant Enterococcus faecalis (8.6%). Tigecycline was the only agent to which all Gram-positive isolates were susceptible. For many of the Gram-negative organisms collected, antimicrobial susceptibilities were lowest among isolates from Italy and highest among isolates from Spain. The notable exception was Acinetobacter baumannii, where the poorest susceptibility profile was among isolates from Spain. For A. baumannii, MIC(90)s of imipenem varied from 1 mg/L for isolates in France and Germany to > or =32 mg/L for isolates from Italy and Spain. Tigecycline was the only agent to maintain an MIC(90) of < or =1 mg/L against isolates from all five countries. The in-vitro activity of tigecycline against both Gram-positive and Gram-negative isolates may make it valuable in the treatment of hospital infections, including those caused by otherwise antimicrobial-resistant organisms.

Rapid identification of oral anaerobic bacteria cultivated from subgingival biofilm by MALDI-TOF-MS.

INTRODUCTION: To facilitate the identification of anaerobes cultivated from periodontal disease, whole cell bacterial identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was evaluated. METHODS: A total of 84 strains (nine reference strains and 75 recent clinical isolates from 33 patients with aggressive periodontitis) previously identified with phenotypic methods were used. All the references and 10 clinical isolates belonging to the same species as the reference strains were genotypically identified by sequence analysis of the 16S ribosomal RNA gene. All the strains were then analyzed using MALDI-TOF-MS. RESULTS: The reference strains of anaerobic bacteria used showed characteristic MALDI-TOF-MS spectra with peaks between m/z 2000 and up to about m/z 13,000. On visual inspection, the similarity of spectra produced by strains of a single genus could be recognized. Obvious differences between spectra produced by strains of different species were also easily noticed. The reproducibility of the method was proved by the similarity of spectra belonging to the same species. The spectra of the Prevotella intermedia strains identified with MALDI clustered together and clustered separately from the spectra of Prevotella nigrescens, proving that MALDI-TOF-MS is an accurate method that is capable of separating these two species. The quality of clustering was characterized by calculating an inconsistency coefficient (Mathworks:/Matlab Reference Manual v2007a/, Statistical toolbox). CONCLUSION: Our results suggest that MALDI-TOF-MS might become a useful method for the identification of anaerobic bacteria, especially for those that cannot be readily identified by biochemical analysis. It may become an attractive system even for the routine identification of clinical isolates.

High-yield amplification of Cryptosporidium parvum in interferon gamma receptor knockout mice.

To date, large-scale production of Cryptosporidium parvum oocysts has only been achieved by amplification in neonatal calves and sheep. Many laboratories currently depend on supplies from external sources and store oocysts for prolonged periods which results in progressive loss of viability. Six to 8-week-old interferon gamma receptor knockout (IFN gamma R-KO) mice on a C57BL/6 background were inoculated by gavage (2000 oocysts/animal). Fecal pellets were collected daily from 7 days post-infection (p.i.) up to 2 weeks p.i. Intestinal oocyst yield was assessed at days 11, 12 and 14 p.i. by homogenization of intestinal tissues. Ether extraction and one or more NaCl flotations were used to purify oocysts. Total recoveries averaged 2.6 x 10(6) oocysts/mouse from fecal material and 3.8 x 10(7) oocysts/mouse from intestinal tissues. Overall, 2.3 x 10(9) purified oocysts were obtained from 60 mice. Recovered oocysts were capable of sporulation and were shown to be infectious both in vitro and in vivo. Oocyst amplification was achieved in only 11-14 days with minimal expense. The simplicity of this method presents a practical alternative for the routine passage, maintenance and storage of C. parvum in biomedical laboratories.

[Antimicrobial and antimycotic therapy of intra-abdominal infections]. / Antibiotika- und Pilztherapie bei intraabdominellen Infektionen.

Antimicrobial chemotherapy is a cornerstone in the treatment of intra-abdominal infections (IAI). The initiation of initial antibiotic therapy must immediately follow the diagnosis of IAI. Selection of the antimicrobial agent is based on the expected pathogenic bacterial spectrum as a calculated empirical therapy. It is impossible to give general recommendations concerning the selection of a certain class of antimicrobial chemotherapeutics, since all available clinical trials were designed to prove noninferiority to the comparator product. Nevertheless several societies developed guidelines and recommendations based on the multitude of clinical trials investigating antimicrobial chemotherapeutics. The antibiotic therapy of postoperative peritonitis has to be implemented according to the patient's risk profile (antibiotic pretreatment, multiresistant pathogens, hospital epidemiology). The development of invasive peritoneal mycoses is rare. The therapy should be guided by the results of the microbiological work-up of the intraperitoneal cultures.

[Clinical features and diagnosis of bronchopulmonary infections in the elderly]. / Klinik und Diagnose bronchopulmonaler Infektionen im Alter.

Diseases of the lung are one of the main causes of morbidity and mortality in the elderly. The risk of respiratory infections is increased due to structural changes, malnutrition, co-morbidity, and a variety of other factors. Bacterial and viral pathogens cause acute bronchitis and exacerbations of chronic bronchitis (AECB). Community acquired pneumonias (CAP) show a different spectrum of pathogens and clinical course in comparison to nosocomial pneumonias (hospital acquired pneumonia, HAP). Institutionalised patients are at risk of a health care associated pneumonia (HCAP), with often a different spectrum of pathogens in comparison to CAP and HAP. Elderly patients with cerebrovascular disease and impairment of swallowing or cough reflexes often suffer from aspiration pneumonias. The mortality is highest in the elderly, comorbid, and immunocompromised patient with nosocomial pneumonia. Important preventive measures include influenza and pneumococcal vaccination, avoidance of immobility, oral hygiene, and sufficient nutrition.

Efficacy of sodium hypochlorite against multidrug-resistant Gram-negative bacteria.

BACKGROUND: Increased antimicrobial resistance has been observed among many bacteria leading to treatment failures in human and veterinary medicine. Disinfection is a prerequisite for infection control and prevention in healthcare settings. Chlorine compounds are cost-effective and accessible worldwide. AIM: To determine the efficacy of sodium hypochlorite (NaOCl) against multidrug-resistant Gram-negative bacteria (MDR-GNB). METHODS: Minimum inhibitory concentrations (MICs) were determined using broth macro-dilution. Bactericidal efficacy was measured by qualitative and quantitative suspension tests followed by practical tests without mechanical action on stainless steel carriers. The guidelines of the German Association for Applied Hygiene were followed. FINDINGS: Results varied remarkably depending on the method. MICs were 0.1% or 0.2% NaOCl. Qualitative suspension tests revealed up to 500-fold lower bactericidal concentrations. Pseudomonas aeruginosa (P = 0.0025) was significantly less susceptible in these tests whereas quantitative suspension tests revealed no significant differences between strains (P > 0.05). Practical tests determined bactericidal concentrations of 0.8-0.32% NaOCl at 1 min of contact and even lower concentrations for longer contact times. At 1 min, five Klebsiella were significantly less susceptible (P = 0.0124), whereas the lower susceptibility of P. aeruginosa was not confirmed. Organic load inhibited bactericidal activity significantly, whereas contact time had a marginal effect. Differing test results underline that MIC determination and qualitative suspension tests may be insufficient approaches to evaluate bacterial susceptibility or resistance. CONCLUSION: NaOCl efficiently reduced Pseudomonas aeruginosa, Acinetobacter spp., and Klebsiella spp., most notably in the absence of organic matter. Strain- and species-specific differences in susceptibility were noticed, but in general MDR-GNB revealed no higher tolerance to NaOCl.

European Committee on Antimicrobial Susceptibility Testing (EUCAST) Technical Notes on antimicrobial susceptibility testing.

The main objectives of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) are to harmonise breakpoints for antimicrobial agents in Europe, and to act as the breakpoint committee for the European Medicines Agency (EMEA) during the registration of new antimicrobial agents. Detailed EUCAST procedures for harmonising and setting breakpoints for antimicrobial agents are available on the EUCAST website. Beginning with the current issue, a series of EUCAST Technical Notes will be published in CMI, based on the rationale documents produced by EUCAST for each of the antimicrobial agents studied, with the aim of highlighting important background information underlying decisions on breakpoints made by EUCAST.

[Infections of hip and knee endoprostheses. Spectrum of pathogens and the role of multiresistant bacteria]. / Infektionen von Hüft- und Knieendoprothesen. Erregerspektrum und die Rolle multiresistenter Bakterien.

BACKGROUND: Because of the rise in primary implantations in elective knee and hip arthroplasty, the number of complications, particularly due to prosthetic infections has increased. Partly due to multimorbidities, an increase in geriatric patients and often unnecessary use of antibiotics, a change in the spectrum of bacteria with an increase in multi-drug resistant pathogens is to be expected. For physicians this creates not only new medical and economic but also sociopolitical challenges. QUESTION: Has the spectrum of bacteria in prosthetic joint infections after total hip arthroplasty (THA) and total knee arthroplasty (TKA) changed during the 12-year period 2001-2012 in our hospital and what role do multi-drug resistant bacteria play? INVESTIGATION COLLECTIVE: A total of 320 patients with prosthetic joint infections (PJI) following TKA or THA could be identified and were included in this study. The sample consisted of 172 patients with an infection after THA (56 % females n = 96 and 44 % males n = 76) with a mean age of 70.9 years (range 39-92 years) and 148 patients with an infection after TKA (55 % females n = 82 and 45 % males n = 66) with a mean age of 70.7 years (range 15-87 years). The bacteria detected and the development over the course of time were evaluated. RESULTS: An increase was found in the occurrence of coagulase negative staphylococci (CNS), in particular Staphylococcus epidermidis (2001-2003 n = 10 and 2010-2012 n = 27). The proportion of oxacillin and methicillin-resistant Staphylococcus epidermidis (MRSE) was also found to increase (0 % in 2001-2003 and 74 % in 2010-2012). A substantial increase in methicillin-resistant Staphylococcus aureus (MRSA) infections could not be found and there was a tendency towards reduction in the total number of Staphylococcus aureus infections. A total of five extended spectrum beta-lactamase (ESBL)-producing bacteria were isolated. CONCLUSION: The spectrum of bacteria has only slightly changed over the years from 2001 to 2012, whereby an increase was only found in the number of CNS infections. Multi-drug resistant bacteria, in particular MRSE have increased. The changes in MRSE found in this study do not appear to warrant a general rethinking of antibiotic prophylaxis.

Activities of various beta-lactams and beta-lactam/beta-lactamase inhibitor combinations against Acinetobacter baumannii and Acinetobacter DNA group 3 strains.

Acinetobacter baumannii and Acinetobacter DNA group 3 are members of the so-called A. calcoaceticus-A. baumannii complex and are important nosocomial pathogens. Multiresistance in these organisms is increasingly frequent, and alternative treatment options are needed. The beta-lactamase inhibitors clavulanate, sulbactam and tazobactam have intrinsic activity against Acinetobacter strains. In the present study, broth microdilution was used to assess the in-vitro activities of currently available beta-lactam/beta-lactamase inhibitor combinations and sulbactam alone against 469 Acinetobacter isolates (A. baumannii, n=395; Acinetobacter DNA group 3, n=74) collected from various laboratories in Germany. Fixed concentrations and fixed ratios of beta-lactamase inhibitors were used. Sulbactam-containing combinations (susceptibility rates of 90.4-92.7% for A. baumannii and 97.3-100% for Acinetobacter DNA group 3) and sulbactam alone were superior to clavulanate- and tazobactam-containing combinations. The activity of sulbactam-containing combinations against members of the A. calcoaceticus-A. baumannii complex was conferred exclusively by the intrinsic activity of the beta-lactamase inhibitor and did not result from enhanced beta-lactam activity. Testing with the inhibitor added at a fixed ratio of inhibitor to beta-lactam appeared to give more reliable results than testing at a fixed concentration of the inhibitor. Resistance to carbapenems (0.3%) remains low in Germany.

Large hospital outbreak of KPC-2-producing Klebsiella pneumoniae: investigating mortality and the impact of screening for KPC-2 with polymerase chain reaction.

BACKGROUND: Multi-drug-resistant Klebsiella pneumoniae carbapenemase (KPC)-2-producing K. pneumoniae are an increasing cause of healthcare-associated infections worldwide. AIMS: To investigate the impact of clinical infection on mortality, and examine the effect of use of KPC-2-specific polymerase chain reaction (PCR) on the time to contact isolation during an outbreak. METHODS: Cases were defined as patients clinically infected or colonized with KPC-2-producing K. pneumoniae between June 2010 and July 2012. Cases were described by demographic and health characteristics, and the association between infection and mortality, adjusted for comorbidities and demographic characteristics, was determined using Poisson regression with robust standard errors. A comparison was made between the time to contact isolation with a culture-based method and PCR using Wilcoxon's rank sum test. FINDINGS: Of 72 cases detected, 17 (24%) had undergone transplantation and 21 (29%) had a malignancy. Overall, 35 (49%) cases were clinically infected, with pneumonia and sepsis being the most common infections. Infection was an independent risk factor for mortality (risk ratio 1.67, 95% confidence interval 0.99-2.82). The median time to contact isolation was 1.5 days (range 0-21 days) using PCR and 5.0 days (range 0-39 days) using culture-based methods (P = 0.003). Intermittent negative tests were observed in 48% (14/29) of cases tested using culture-based methods. CONCLUSION: KPC-2-producing K. pneumoniae mainly affect severely ill patients. Half of the cases developed clinical infection, associated with increased risk of death. As PCR accelerates isolation and provides the opportunity for preventive measures in colonized cases, its use should be implemented promptly during outbreaks. Further studies are needed to enhance knowledge about KPC detection patterns and to adjust screening guidelines.

Isolation of Clostridium innocuum from cases of recurrent diarrhea in patients with prior Clostridium difficile associated diarrhea.

Clostridium innocuum isolates resistant to vancomycin (MIC values of 16-24 microg/mL) were isolated from three patients with recurrent Clostridium difficile -associated diarrhea (CDAD). We discuss the clinical significance and problems associated with the identification and differentiation of these two clostridial species, which may result in misdiagnosis of patients.

Interpretive criteria of ceftibuten disk diffusion susceptibility tests according to the DIN 58 940 method.

OBJECTIVE: This study aimed to establish interpretive criteria for agar diffusion tests with ceftibuten disks according to DIN standards. METHODS: Minimal inhibitory concentrations (MICs) and inhibition zones produced by ceftibuten in the disk diffusion test were determined for 275 recent bacterial isolates, including 11 species with 25 strains each. Regression analysis was performed for two disk loads (10 microg and 30 microg). RESULTS: Correlation of MICs and zone diameters was good, with correlation coefficients of r = - 0.97 for both tested disk loads. Evaluation of the calculated zone size criteria for all species showed no very major discrepancies or no major discrepancies. The 30-microg disks, however, produced unacceptably large inhibition zones for very susceptible strains, so that usage of 10-microg disks must be recommended when testing according to DIN standards. CONCLUSION: Based on the MIC breakpoints recommended by the DIN (> or =8 mg/L and < or = 1 mg/L), the following interpretive breakpoints for disk diffusion susceptibility tests with 10-microg ceftibuten disks were calculated using regression line analysis: < or =19 mm for resistance and > or = 27 mm for susceptiblity. Proposed inhibition zone diameters for the reference strain Escherichia coli ATCC 25922 are between 31 and 36 mm.