Confirmed cases and report of clusters of severe infections due to Clostridium difficile PCR ribotype 027 in Germany

Evaluation of risk factors for a fulminant Clostridium difficile infection after cardiac surgery: a single-center, retrospective cohort study

Background

Clostridium difficile (CD) is the most common pathogen causing nosocomial diarrhea. The clinical presentation ranges from mild diarrhea to severe complications, including pseudomembranous colitis, toxic megacolon, sepsis, and multi-organ failure. When the disease takes a fulminant course, death ensues rapidly in severe and complex cases. Preventive screening or current prophylactic therapies are not useful. Therefore, this study was conducted to detect risk factors for a fulminant CD infection (CDI) in patients undergoing cardiac surgery.

Methods

Between April 1999 and April 2011, a total of 41,466 patients underwent cardiac surgery at our institution. A review of our hospital database revealed 1256 patients (3.0%) with post-operative diarrheal disease who tested positive for CD; these patients comprised the cohort of this observational study. A fulminant CDI occurred in 153 of these patients (12.2%), which was diagnosed on the basis of gastrointestinal complications, e.g. pseudomembranous colitis, and/or the need for post-cardiac surgery laparotomy. Demographic, peri-operative, and survival data were analyzed, and predictors of a fulminant CDI were assessed by binary logistic regression analysis.

Results

The 30-day mortality was 6.1% (n = 77) for the entire cohort, with significantly higher mortality among patients with a fulminant CDI (21.6% vs. 4.0%, p <  0.001). Overall mortality (27.7%, n = 348) was also higher for patients with a fulminant course of the disease (63.4% vs. 22.8%, p <  0.001), and a laparotomy was required in 36.6% (n = 56) of the fulminant cases. Independent predictors of a fulminant CDI were: diabetes mellitus type 2 (OR 1.74, CI 1.15–2.63, p = 0.008), pre-operative ventilation (OR 3.52, CI 1.32–9.35, p = 0.012), utilization of more than 8 units of red blood cell concentrates (OR 1.95, CI 1.01–3.76, p = 0.046) or of more than 5 fresh-frozen plasma units (OR 3.38, CI 2.06–5.54, p <  0.001), and a cross-clamp time > 130 min (OR 1.93, CI 1.12–3.33, p = 0.017).

Conclusions

We identified several independent risk factors for the development of a fulminant CDI after cardiac surgery. Close monitoring of high-risk patients is important in order to establish an early onset of therapy and thus to prevent a CDI from developing a fulminant course after cardiac surgery.

[Clostridium difficile in visceral surgery]

BACKGROUND

For surgeons the early identification of patients with clostridium difficile infections (CDI) is important, because the incidence and virulence of this potentially life-threatening disease are increasing.

OBJECTIVES

The aim of this study was to describe the frequency of CDI among surgical patients, to analyze which treatment was successful and to define which factors were associated with mortality.

METHODS

A retrospective analysis of patients with CDI was performed.

RESULTS

From January 2004 to June 2012 the overall incidence of CDI among all departments at the St. Josef Hospital, Ruhr University Bochum was 0.6 % (1669 out of 301,919 patients). In 2004 the number of surgical patients with CDI was 1 which increased to 41 in 2011. Before the diagnosis of CDI was made 84 % (151 out of 179) of patients had received an antibiotic treatment. Conservative management of CDI was performed with metronidazole in 75 % (134 out of 179), 60 % (107 out of 179) received vancomycin, while 44 % (79 out of 179) received a combination of metronidazole and vancomycin, tygecycline or fidaxomidin. The overall mortality was 7 % (12 out of 179). There was a significant association with mortality for patients with sepsis, readmission to the intensive care unit (ICU), requirement for vasopressor therapy and intubation with mechanical ventilation. In 4 % of patients (7 out of 179) colectomy was carried out. Despite maximum intensive care management, 86 % (6 out of 7) of patients who underwent colectomy ultimately died.

CONCLUSION

Although conservative management is successful for most patients with CDI, the mortality is high for patients who require intensive care management secondary to CDI. Mortality after colectomy for CDI is almost 100 %, mostly because the operation is usually only performed as a last resort in patients with sepsis. The most important risk factor for CDI is a prior antibiotic therapy.

Tracing the Spread of Clostridium difficile Ribotype 027 in Germany Based on Bacterial Genome Sequences

We applied whole-genome sequencing to reconstruct the spatial and temporal dynamics underpinning the expansion of Clostridium difficile ribotype 027 in Germany. Based on re-sequencing of genomes from 57 clinical C. difficile isolates, which had been collected from hospitalized patients at 36 locations throughout Germany between 1990 and 2012, we demonstrate that C. difficile genomes have accumulated sequence variation sufficiently fast to document the pathogen's spread at a regional scale. We detected both previously described lineages of fluoroquinolone-resistant C. difficile ribotype 027, FQR1 and FQR2. Using Bayesian phylogeographic analyses, we show that fluoroquinolone-resistant C. difficile 027 was imported into Germany at least four times, that it had been widely disseminated across multiple federal states even before the first outbreak was noted in 2007, and that it has continued to spread since.

Increased incidence of Clostridium difficile PCR ribotype 027 in Hesse, Germany, 2011 to 2013

After the first outbreak of Clostridium difficile PCR ribotype (RT) 027 in Germany in 2007, no further outbreaks were reported until the recent re-emergence of RT 027 in Hesse, a federal state with 6 million inhabitants located in south-west Germany. We undertook a survey to determine the prevalence of RT 027 and other strains in a prospective study. From January 2011 to July 2013, we analysed 291 specimens from patients diagnosed with C. difficile infection (CDI) in 40 healthcare facilities in Hesse. The mean incidence of CDI in hospitals including at least 10 patients in the survey was 9.9 per 10,000 patient days (range 4.8-22.8) in November 2012. We obtained 214 toxigenic C. difficile isolates. RT 001 was the most prevalent (31.8%). RT 027, the second most common type (26.6%), was prevalent in all hospitals (n=14) from which at least seven isolates were available for typing, but its frequency varied considerably (range: 9.1–70%). The annual frequency of RT 027 increased from 21.4% in 2011 to 30.0% in 2013 (p=0.04). Our study indicates that infections with C. difficile RT 027 are now prevalent in Hesse. It underscores the need for surveillance programmes to analyse the molecular epidemiology of C. difficile.

Seasonality of Clostridium difficile infections in Southern Germany

Between 2000 and 2009, the total number of patients with Clostridium difficile infections increased considerably in Southeastern Germany. A clear seasonality was observed with a higher number of affected patients occurring in the winter months (January-March). Moxifloxacin and erythromycin-resistant C. difficile PCR ribotypes 001 (72%) and 027 (4·6%) were the most commonly isolated strains.

Clostridium difficile infection: monoclonal or polyclonal genesis?

Clostridium difficile is considered to be a leading cause of hospital-acquired diarrhea. C. difficile (CDI) infection shows a high rate of recurrence. There would have to be a predominantly monoclonal mechanism of CDI within individual patients in order for molecular epidemiologic tools such as polymerase chain reaction (PCR) ribotyping to be useful in outbreak investigation or differentiation between infection relapse versus re-infection. It was the aim of our study to determine whether CDI is of monoclonal or of polyclonal genesis. Between December 2009 and June 2010, 11 patients with nosocomial CDI were chosen arbitrarily. Five individual colonies of C. difficile were picked from each of the primary culture plates. Of 55 isolates gained, 47 were available for PCR ribotyping (eight isolates failed attempts to re-culture). Among these 47 isolates, eight different PCR ribotypes were identified. Only one of the 11 patients had a stool sample that yielded more than one ribotype (PCR ribotypes 438 and 232); this 67-year-old female cancer patient was already suffering from recurring diarrhea prior to the fatal episode of colitis which was subsequently investigated. We conclude that polyclonal infections may occasionally occur in patients with CDI. Our findings of predominantly monoclonal origin of CDI within patients suggest that molecular epidemiologic investigations can be used reliably for outbreak investigations or discrimination between relapse and re-infection.

Fluoroquinolone resistance and Clostridium difficile, Germany

We characterized 670 Clostridium difficile isolates collected from patients in 84 hospitals in Germany in 2008. PCR ribotyping showed high prevalence of ribotype 001 and restricted dissemination of ribotype 027 strains. Fluoroquinolone resistance and associated gyrase mutations were frequent in various ribotypes, but no resistance to metronidazole or vancomycin was noted.

Clostridium difficile PCR ribotype 027: assessing the risks of further worldwide spread

Highly virulent strains of Clostridium difficile have emerged since 2003, causing large outbreaks of severe, often fatal, colitis in North America and Europe. In 2008–10, virulent strains spread between continents, with the first reported cases of fluoroquinolone-resistant C difficile PCR ribotype 027 in three Asia-Pacific countries and Central America. We present a risk assessment framework for assessing risks of further worldwide spread of this pathogen. This framework first requires identification of potential vehicles of introduction, including international transfers of hospital patients, international tourism and migration, and trade in livestock, associated commodities, and foodstuffs. It then calls for assessment of the risks of pathogen release, of exposure of individuals if release happens, and of resulting outbreaks. Health departments in countries unaffected by outbreaks should assess the risk of introduction or reintroduction of C difficile PCR ribotype 027 using a structured risk-assessment approach.

[Clostridium difficile-associated infections. How dangerous are the new strains?]

In recent years, a global increase of Clostridium difficile-associated infections (CDI) and the emergence of new hypervirulent strains causing numerous outbreaks was noticed. The appearance of these strains was accompanied by increased morbidity and mortality, affecting patients previously unknown to be at risk for CDI. Meanwhile, these hypervirulent strains occur in Germany as well. So far, the changing epidemiology of CDI did neither change diagnosis nor therapy of CDI but necessitates a series of preventive measures like the surveillance of CDI and contact precautions while caring for affected patients. If there are complicated or severe cases of CDI, the hypervirulent strains should be suspected and stool culture for isolation of C. difficile should be aimed.

Molecular analysis of the gyrA and gyrB quinolone resistance-determining regions of fluoroquinolone-resistant Clostridium difficile mutants selected in vitro

Recent studies have suggested that exposure to fluoroquinolones represents a risk factor for the development of Clostridium difficile infections and that the acquisition of resistance to the newer fluoroquinolones is the major reason facilitating wide dissemination. In particular, moxifloxacin (MX) and levofloxacin (LE) have been recently associated with outbreaks caused by the C. difficile toxinotype III/PCR ribotype 027/pulsed-field gel electrophoresis type NAP1 strain. In this study, we evaluated the potential of MX and LE in the in vitro development of fluoroquinolone resistance mediated by GyrA and GyrB alterations. Resistant mutants were obtained from five C. difficile parent strains, susceptible to MX, LE, and gatifloxacin (GA) and belonging to different toxinotypes, by selection in the presence of increasing concentrations of MX and LE. Stable mutants showing substitutions in GyrA and/or GyrB were obtained from the parent strains after selection by both antibiotics. Mutants had MICs ranging from 8 to 128 microg/ml for MX, from 8 to 256 microg/ml for LE, and from 1.5 to > or = 32 microg/ml for GA. The frequency of mutation ranged from 3.8 x 10(-6) to 6.6 x 10(-5) for MX and from 1.0 x 10(-6) to 2.4 x 10(-5) for LE. In total, six different substitutions in GyrA and five in GyrB were observed in this study. The majority of these substitutions has already been described for clinical isolates or has occurred at positions known to be involved in fluoroquinolone resistance. In particular, the substitution Thr82 to Ile in GyrA, the most common found in resistant C. difficile clinical isolates, was observed after selection with LE, whereas the substitution Asp426 to Val in GyrB, recently described in toxin A-negative/toxin B-positive epidemic strains, was observed after selection with MX. Interestingly, a reduced susceptibility to fluoroquinolones was observed in colonies isolated after the first and second steps of selection by both MX and LE, with no substitution in GyrA or GyrB. The results suggest a relevant role of fluoroquinolones in the emergence and selection of fluoroquinolone-resistant C. difficile strains also in vivo.

Rapid detection of the Clostridium difficile ribotype 027 tcdC gene frame shift mutation at position 117 by real-time PCR and melt curve analysis

The emergence of the hypervirulent strain Clostridium difficile PCR ribotype 027 has increased the necessity for rapid C. difficile typing tests for clinical and epidemiological purposes. We developed a rapid real-time polymerase chain reaction (PCR) test for the detection of C. difficile. As the target, we chose the tcdC gene, which encodes for a negative regulator in toxin production. A deletion at position 117 of the tcdC gene, which is associated with severe tcdC truncation, is well conserved in all PCR ribotype 027 isolates. Probe sequences of the real-time PCR test were designed to result in distinct melt profiles for sequence variations at positions 117 to 120 of the tcdC gene. The tcdC gene deletion at position 117 was easily detected with real-time PCR and melt curve analysis in all C. difficile ribotype 027 isolates. In five non-027 strains and 46 hospitalised patient samples, melt curve analysis detected no deletion. PCR results were confirmed by DNA sequencing. The combination of real-time PCR and melt curve analysis is a rapid and accurate method for the detection of C. difficile DNA and simultaneous screening for the tcdC gene deletion at position 117, which is closely related to the C. difficile PCR ribotype 027 strain.