Clostridium difficile-associated Enteric Disease

Gut microbiome and plasma lipidome analysis reveals a specific impact of Clostridioides difficile infection on intestinal bacterial communities and sterol metabolism

Clostridioides difficile infection (CDI) causes alterations in the intestinal microbiota, frequently associated with changes in the gut metabolism of bile acids and cholesterol. In addition to the impact on microbiome composition and given the metabolic changes occurring during CDI, our work focuses on the importance to know the effects at the local and systemic levels, both during the infection and its treatment, by paying particular attention to plasma lipid metabolism due to its relationship with CDI pathogenesis. Specific changes, characterized by a loss of microbial richness and diversity and related to a reduction in short-chain acid-producing bacteria and an increase in bile salt hydrolase-producing bacteria, were observed in the gut microbiota of CDI patients, especially in those suffering from recurrent CDI (RCDI). However, gut microbiota showed its ability to restore itself after treatment, resembling healthy individuals, in those patients treated by fecal microbiome transfer (FMT), in contrast with those treated with antibiotics, and displaying increased levels of Eubacterium coprostanoligenes, a cholesterol-reducing anaerobe. Interestingly, changes in plasma lipidome revealed a global depletion in circulating lipids in CDI, with the largest impact on cholesteryl esters. CDI patients also showed a specific and consistent decrease in the levels of lipid species containing linoleic acid-an essential fatty acid-which were only partially recovered after antibiotic treatment. Analysis of the plasma lipidome reflects CDI impact on the gut microbiota and its metabolism, evidencing changes in sterol and fatty acid metabolism that are possibly related to specific alterations observed in gut microbial communities of CDI patients.

IMPORTANCE

There is increasing evidence about the influence the changes in microbiota and its metabolism has on numerous diseases and infections such as Clostridioides difficile infection (CDI). The knowledge of these changes at local and systemic levels can help us manage this infection to avoid recurrences and apply the best therapies, such as fecal microbiota transfer (FMT). This study shows a better restoration of the gut in FMT-treated patients than in antibiotic-treated patients, resembling healthy controls and showing increased levels of cholesterol-reducing bacteria. Furthermore, it evidences the CDI impact on plasma lipidome. We observed in CDI patients a global depletion in circulating lipids, particularly cholesteryl esters, and a specific decrease in linoleic acid-containing lipids, an essential fatty acid. Our observations could impact CDI management because the lipid content was only partially recovered after treatment, suggesting that continued nutritional support, aiming to restore healthy lipid levels, could be essential for a full recovery.

Complete Genome Sequencing and Comparative Phenotypic Analysis Reveal the Discrepancy Between Clostridioides difficile ST81 and ST37 Isolates

Toxin A-negative, toxin B-positive Clostridioides difficile strains, which primarily include the ST81 and ST37 genotypes, are predominant in C. difficile infections leading to antibiotic-associated diarrhea in China. Recently, ST81 has been reported as the most prevalent genotype rather than ST37, although the genetic and functional characteristics of the two genotypes remain ambiguous. In this study, we conducted comprehensive comparative analysis of these two genotypes through complete genome sequencing and phenotypic profiling. The whole genome sequencing revealed that the ST81 and ST37 isolates were closely related genetically with similar gene compositions, and high rate of the core genome shared. The integrative and conjugative elements identified in ST81 were similar to those in ST37, albeit with more diverse and insertion regions. By characterizing the phenotypes related to colonization or survival in the host, we found that the ST81 isolates exhibited robust colonization ability and survival both in vitro and in vivo, enhanced spore production, and slightly increased motility, which may be attributable to the discrepancy in non-synonymous single-nucleotide polymorphisms in the relevant functional genes. Furthermore, the ST81 isolates displayed a significantly higher rate of resistance to fluoroquinolones compared with the ST37 isolates (94.12% vs. 62.5%) and mostly carried the amino acid substitution Asp426Val in GyrB. In summary, the results of our study indicate that ST81 isolates exhibit enhanced ability to transmit between hosts and survive in harsh environments, providing key genetic insights for further epidemiological investigations and surveillance of C. difficile infection.

Pragmatic Strategy for Fecal Specimen Storage and the Corresponding Test Methods for Clostridioides difficile Diagnosis

The quality of fecal specimens is one of the factors responsible for successful Clostridioides difficile infection (CDI) diagnosis. The quality depends largely on the storage conditions, including the temperature and time period. In this study, we organized the outputs of previous studies, filled experimental gaps in the knowledge of storage conditions, and introduced a pragmatic strategy for fecal storage for CDI diagnosis. A 5-step pathway was adopted to develop the fecal specimen storage strategy as follows: step 1, bibliomic analysis; step 2, experimental gap-filling; step 3, comparative evaluation; step 4, strategy development; step 5, internal review. Step 1 identified eight articles providing experimental information on the effects of fecal specimen storage conditions on the effectiveness of C. difficile detection methods. Step 2 provided additional quantitative data on C. difficile vegetative and spore cell viability and DNA stability. All previous and current results were compared (step 3). In step 4, fir general and nine special strategies were developed, followed by an internal review of the overall approaches (step 5). It is recommended to separate fecal samples into aliquots before testing and storing them. It is particularly recommended that fecal specimen samples be stored for CDI diagnosis at 4 °C for up to 60 days for all test methods.

Tilivalline- and Tilimycin-Independent Effects of Klebsiella oxytoca on Tight Junction-Mediated Intestinal Barrier Impairment

Klebsiella oxytoca causes antibiotic-associated hemorrhagic colitis and diarrhea. This was attributed largely to its secreted cytotoxins tilivalline and tilimycin, inductors of epithelial apoptosis. To study whether Klebsiella oxytoca exerts further barrier effects, T84 monolayers were challenged with bacterial supernatants derived from tilivalline/tilimycin-producing AHC6 or its isogeneic tilivalline/tilimycin-deficient strain Mut-89. Both preparations decreased transepithelial resistance, enhanced fluorescein and FITC-dextran-4kDa permeabilities, and reduced expression of barrier-forming tight junction proteins claudin-5 and -8. Laser scanning microscopy indicated redistribution of both claudins off the tight junction region in T84 monolayers as well as in colon crypts of mice infected with AHC6 or Mut-89, indicating that these effects are tilivalline/tilimycin-independent. Furthermore, claudin-1 was affected, but only in a tilivalline/tilimycin-dependent manner. In conclusion, Klebsiella oxytoca induced intestinal barrier impairment by two mechanisms: the tilivalline/tilimycin-dependent one, acting by increasing cellular apoptosis and a tilivalline/tilimycin-independent one, acting by weakening the paracellular pathway through the tight junction proteins claudin-5 and -8.

Changes in molecular epidemiology and antimicrobial resistance profiles of Clostridioides (Clostridium) difficile strains in the United States between 2011 and 2017

PCR ribotyping and antimicrobial susceptibility testing were used to characterize 940 Clostridioides (Clostridium) difficile isolates collected from 26 U S. hospitals over three time periods from 2011 to 2017. The proportion of ribotype (RT) 027 isolated during the three surveys decreased significantly over time from 31% in 2011-2012, to 22% in 2013-2014, and to 14% in 2015-2017 (p < 0.001 and p = 0.010, respectively), while we observed an increase in prevalence of RT106, that rose from 7% in our first survey to 19% of isolates in our last survey (p < 0.001). In addition, both RT056 and RT002 rose from 3% to 10% (p < 0.001). The proportions of all other ribotypes remained steady over time, and RT014/020 was the third most common strain type in our convenience sample in the final survey. Overall, resistance to moxifloxacin, rifampin, and vancomycin decreased during our studies, mainly due to the decline in RT027 isolates. A decrease in moxifloxacin resistance and an increase in tetracycline resistance were found among RT027 strains isolated in the last survey. Although the proportion of RT027 isolates declined, multidrug resistance among this ribotype continues to be common.

Phylogeny-corrected identification of microbial gene families relevant to human gut colonization

The mechanisms by which different microbes colonize the healthy human gut versus other body sites, the gut in disease states, or other environments remain largely unknown. Identifying microbial genes influencing fitness in the gut could lead to new ways to engineer probiotics or disrupt pathogenesis. We approach this problem by measuring the statistical association between a species having a gene and the probability that the species is present in the gut microbiome. The challenge is that closely related species tend to be jointly present or absent in the microbiome and also share many genes, only a subset of which are involved in gut adaptation. We show that this phylogenetic correlation indeed leads to many false discoveries and propose phylogenetic linear regression as a powerful solution. To apply this method across the bacterial tree of life, where most species have not been experimentally phenotyped, we use metagenomes from hundreds of people to quantify each species' prevalence in and specificity for the gut microbiome. This analysis reveals thousands of genes potentially involved in adaptation to the gut across species, including many novel candidates as well as processes known to contribute to fitness of gut bacteria, such as acid tolerance in Bacteroidetes and sporulation in Firmicutes. We also find microbial genes associated with a preference for the gut over other body sites, which are significantly enriched for genes linked to fitness in an in vivo competition experiment. Finally, we identify gene families associated with higher prevalence in patients with Crohn's disease, including Proteobacterial genes involved in conjugation and fimbria regulation, processes previously linked to inflammation. These gene targets may represent new avenues for modulating host colonization and disease. Our strategy of combining metagenomics with phylogenetic modeling is general and can be used to identify genes associated with adaptation to any environment.

Importance of Molecular Methods to Determine Whether a Probiotic is the Source of Lactobacillus Bacteremia

There has been an increasing interest in the use of probiotic products for the prevention of Clostridium difficile infection (CDI). Bio-K+(®) is a commercial probiotic product comprising three strains of lactobacilli--Lactobacillus acidophilus CL1285(®), Lact. casei LBC80R(®) and Lact. rhamnosus CLR2(®)--that have been applied to prevent CDI. Generally considered as safe, lactobacilli have potential to cause bacteremia, endocarditis and other infections. The source of Lactobacillus bacteremia can be normal human flora or lactobacilli-containing probiotic. The aim of this study was to assess whether probiotic lactobacilli caused bacteremia and to show the value of molecular identification and typing techniques to determine probiotic and patient strain relatedness. We report an episode of Lactobacillus bacteremia in a 69-year-old man admitted to a hospital with severe congestive heart failure. During his hospitalization, he required long-term antibiotic therapy. Additionally, the patient received Bio-K+(®) probiotic as part of a quality improvement project to prevent CDI. Subsequently, Lactobacillus bacteremia occurred. Two independent blinded laboratory evaluations, using pulse field gel electrophoresis, 16S rRNA gene sequencing and DNA fingerprint analysis (rep-PCR), were performed to determine whether the recovered Lact. acidophilus originated from the probiotic product. Ultimately, the patient strain was identified as Lact. casei and both laboratories found no genetic relation between the patient's strain and any of the probiotic lactobacilli. This clinical case of lactobacillus bacteremia in the setting of probiotic exposure demonstrates the value of using discriminatory molecular methods to clearly determine whether there were a link between the patient's isolate and the probiotic strains.

Low sensitivity of fecal toxin A/B enzyme immunoassay for diagnosis of Clostridium difficile infection in immunocompromised patients

The optimal approach in laboratory diagnosis of Clostridium difficile infection (CDI) is still not well defined. Toxigenic culture (TC) or alternatively fecal toxin assay by cell cytotoxicity neutralization assay are considered to be the reference standard, but these methods are time-consuming and labor intensive. In many medical centers, diagnosis of CDI is therefore still based on fecal toxin A/B enzyme immunoassay (EIA) directly from stool alone, balancing cost and speed against limited diagnostic sensitivity. The aim of the study was to assess in which patient population the additional workload of TC is justified. All consecutive stool specimens submitted for diagnosis of suspected CDI between 2004 and 2011 at a tertiary-care center were examined by toxin EIA and TC. Clinical data of patients with established diagnosis of CDI were collected in a standardized case-report form. From 12,481 stool specimens submitted to the microbiologic laboratory, 480 (3.8%) fulfilled CDI criteria; 274 (57.1%) were diagnosed by toxin EIA; and an additional 206 (42.9%) were diagnosed by TC when toxin EIA was negative. Independent predictors for negative toxin EIA but positive TC were high-dose corticosteroids (odds ratio (OR) 2.97, 95% confidence interval (CI) 1.50-5.90, p 0.002), leukocytopenia <1000/μL (OR 2.52, 95% CI 1.22-5.23, p 0.013) and nonsevere CDI (OR 2.21, 95% CI 1.39-3.50, p 0.001). There was no difference in outcomes such as in-hospital mortality and recurrence between both groups. In conclusion, negative toxin EIA does not rule out CDI in immunocompromised patients in the setting of relevant clinical symptoms. Methods with improved sensitivity such as TC or PCR should be used, particularly in this patient population.

An optimized, synthetic DNA vaccine encoding the toxin A and toxin B receptor binding domains of Clostridium difficile induces protective antibody responses in vivo

Clostridium difficile-associated disease (CDAD) constitutes a large majority of nosocomial diarrhea cases in industrialized nations and is mediated by the effects of two secreted toxins, toxin A (TcdA) and toxin B (TcdB). Patients who develop strong antitoxin antibody responses can clear C. difficile infection and remain disease free. Key toxin-neutralizing epitopes have been found within the carboxy-terminal receptor binding domains (RBDs) of TcdA and TcdB, which has generated interest in developing the RBD as a viable vaccine target. While numerous platforms have been studied, very little data describes the potential of DNA vaccination against CDAD. Therefore, we created highly optimized plasmids encoding the RBDs from TcdA and TcdB in which any putative N-linked glycosylation sites were altered. Mice and nonhuman primates were immunized intramuscularly, followed by in vivo electroporation, and in these animal models, vaccination induced significant levels of both anti-RBD antibodies (blood and stool) and RBD-specific antibody-secreting cells. Further characterization revealed that sera from immunized mice and nonhuman primates could detect RBD protein from transfected cells, as well as neutralize purified toxins in an in vitro cytotoxicity assay. Mice that were immunized with plasmids or given nonhuman-primate sera were protected from a lethal challenge with purified TcdA and/or TcdB. Moreover, immunized mice were significantly protected when challenged with C. difficile spores from homologous (VPI 10463) and heterologous, epidemic (UK1) strains. These data demonstrate the robust immunogenicity and efficacy of a TcdA/B RBD-based DNA vaccine in preclinical models of acute toxin-associated and intragastric, spore-induced colonic disease.

Intestinal alkaline phosphatase prevents antibiotic-induced susceptibility to enteric pathogens

OBJECTIVE

To determine the efficacy of oral supplementation of the gut enzyme intestinal alkaline phosphatase (IAP) in preventing antibiotic-associated infections from Salmonella enterica serovar Typhimurium (S. Typhimurium) and Clostridium difficile.

BACKGROUND

The intestinal microbiota plays a pivotal role in human health and well-being. Antibiotics inherently cause dysbiosis, an imbalance in the number and composition of intestinal commensal bacteria, which leads to susceptibility to opportunistic bacterial infections. Previously, we have shown that IAP preserves the normal homeostasis of intestinal microbiota and that oral supplementation with calf IAP (cIAP) rapidly restores the normal gut flora. We hypothesized that oral IAP supplementation would protect against antibiotic-associated bacterial infections.

METHODS

C57BL/6 mice were treated with antibiotic(s) ± cIAP in the drinking water, followed by oral gavage of S. Typhimurium or C. difficile. Mice were observed for clinical conditions and mortality. After a defined period of time, mice were killed and investigated for hematological, inflammatory, and histological changes.

RESULTS

We observed that oral supplementation with cIAP during antibiotic treatment protects mice from infections with S. Typhimurium as well as with C. difficile. Animals given IAP maintained their weight, had reduced clinical severity and gut inflammation, and showed improved survival.

CONCLUSIONS

Oral IAP supplementation protected mice from antibiotic-associated bacterial infections. We postulate that oral IAP supplementation could represent a novel therapy to protect against antibiotic-associated diarrhea (AAD), C. difficile-associated disease (CDAD), and other enteric infections in humans.

Antimicrobial susceptibility of clostridium difficile clinical isolates in iran

Background

Clostridium difficile infection (CDI) is major growing problem in hospitals and its high incidence has been reported in recent years.

Objectives

The aim of this study was to investigate the antimicrobial susceptibility patterns of C. difficile clinical isolates against antibiotics commonly used for treatment CDI in hospitalized patients.

Material and Methods

During a 12 month study, 75 C. difficile isolates were collected from 390 patients with CDI. All samples were treated with alcohol and yeast extract broth. The treated suspensions were cultured on a selective cycloserine cefoxitin fructose agar (CCFA) supplemented with 5% sheep blood and incubated in anaerobic conditions, at 37 °C for 5 days. Cdd-3, tcdA and tcdB genes were identified using PCR assay.

Results

The prevalence of A⁺B⁺ , A⁺ B^- and A^- B⁺ strains were 64(85.3%), 5(6.7%) and 6(8%) respectively. In vitro susceptibility of 75 clinical isolates of C. difficile to 5 antimicrobial agents, including metronidazole, vancomycin, clindamycin, erythromycin and cefotaxime were investigated by Clinical and Laboratory Standards Institute (CLSI) agar dilution method. Metronidazole and vancomycin had good activity against C. difficile isolates with MIC90s of 2 and 1 µg/ml, respectively. Seventy one (94.6%) of strains was inhibited by concentrations that did not exceed 2µg/ml for metronidazole. Resistant to metronidazole observed in 5.3% of isolates. Forty three (57.3%) of the isolates were resistant to erythromycin. Of 43 resistant strains to erythromycin, 9 (12%) isolates had high-level MIC of more than 64 µg/ml. All strains were resistant to cefotaxime. Sixty seven (89.3%) isolates were resistant to clindamycin (MIC90s > 256 µg/ml) and only 6.7% were sensitive to clindamycin. Multidrug-resistant (three or more antibiotics) was seen in 36(48%) isolates.

Conclusions

Metronidazole and vancomycin still seem to be most effective drugs for treatment CDI.

Detection of Clostridium difficile toxin A/B genes by multiplex real-time PCR for the diagnosis of C. difficile infection

Toxigenic Clostridium difficile culture is considered to be the standard diagnostic method for the detection of C. difficile infection (CDI). Culture methods are time-consuming and although enzyme immunoassay is rapid and easy to use, it has low sensitivity. In the present study, the AdvanSure CD real-time (RT)-PCR kit (LG Life Sciences) was evaluated for its ability to detect C. difficile toxin A (tcdA) and B (tcdB) genes, simultaneously. A total of 127 fresh diarrhoeal stool specimens, submitted to the clinical microbiology laboratory for C. difficile culture, were tested. C. difficile toxins and toxin genes were detected with a VIDAS C. difficile A&B (VIDAS-CDAB) enzyme-linked fluorescent immunoassay (ELFA) and the AdvanSure RT-PCR kit, respectively, according to the manufacturers' instructions. Their performance was compared with a standard toxigenic culture method as a reference. The sensitivity, specificity and positive and negative predictive values using the AdvanSure RT-PCR kit were 100 %, 98.3 %, 84.6 % and 100 %, respectively, while those of the VIDAS-CDAB system were 63.6 %, 100 %, 100 % and 96.6 %, respectively. Four tcdA(+)/tcdB(+) strains of C. difficile were detected with the AdvanSure RT-PCR kit, which offers comparable sensitivity and specificity to the reference method with a turnaround time of ~3 hours.

Clostridium difficile colonization in early infancy is accompanied by changes in intestinal microbiota composition

Clostridium difficile is a major enteric pathogen responsible for antibiotic-associated diarrhea. Host susceptibility to C. difficile infections results partly from inability of the intestinal microbiota to resist C. difficile colonization. During early infancy, asymptomatic colonization by C. difficile is common and the intestinal microbiota shows low complexity. Thus, we investigated the potential relationship between the microbiota composition and the implantation of C. difficile in infant gut. Fecal samples from 53 infants, ages 0 to 13 months, 27 negative and 26 positive for C. difficile, were studied. Dominant microbiota profiles were assessed by PCR-temporal temperature gradient gel electrophoresis (TTGE). Bacterial signatures of the intestinal microbiota associated with colonization by C. difficile were deciphered using principal component analysis (PCA). Resulting bands of interest in TTGE profiles were excised, sequenced, and analyzed by nucleotide BLAST (NCBI). While global biodiversity was not affected, interclass PCA on instrumental variables highlighted significant differences in dominant bacterial species between C. difficile-colonized and noncolonized infants (P = 0.017). Four bands were specifically associated with the presence or absence of C. difficile: 16S rRNA gene sequences related to Ruminococcus gnavus and Klebsiella pneumoniae for colonized infants and to Bifidobacterium longum for noncolonized infants. We demonstrated that the presence of C. difficile in the intestinal microbiota of infants was associated with changes in this ecosystem's composition. These results suggest that the composition of the gut microbiota might be crucial in the colonization process, although the chronology of events remains to be determined.

Clostridium difficile isolates resistant to fluoroquinolones in Italy: emergence of PCR ribotype 018

Recent evidence strongly suggests an association between the use of fluoroquinolones and Clostridium difficile infection (CDI). Resistance to fluoroquinolones has been described not only in the hypervirulent strain 027, but also in other important PCR ribotypes circulating in hospital settings. In a European prospective study conducted in 2005, strains resistant to moxifloxacin represented 37.5% of C. difficile clinical isolates. In this study, we investigated a sample of 147 toxigenic C. difficile isolates, collected in Italy from 1985 to 2008, for the presence of mutations in gyr genes that conferred resistance to fluoroquinolones based on a LightCycler assay. Results were confirmed by the determination of MICs for moxifloxacin. Strains resistant to moxifloxacin were also investigated for resistance to three other fluoroquinolones and for a possible association between fluoroquinolone and macrolide-lincosamide-streptogramin B resistance. C. difficile isolates were typed by PCR ribotyping. In total, 50 clinical isolates showed substitutions in gyr genes and were resistant to fluoroquinolones. Ninety-six percent of the C. difficile resistant isolates showed the substitution Thr82-to-Ile in GyrA, as already observed in the majority of resistant strains worldwide. A significant increase of resistance (P < 0.001) was observed in the period 2002 to 2008 (56% resistant) compared to the period 1985 to 2001 (10% resistant). Coresistance with erythromycin and/or clindamycin was found in 96% (48/50) of the isolates analyzed and, interestingly, 84% of resistant strains were erm(B) negative. The majority of the fluoroquinolone-resistant isolates belonged to PCR ribotype 126 or 018. PCR ribotype 126 was the most frequently found from 2002 to 2005, whereas PCR ribotype 018 was predominant in 2007 and 2008 and still represents the majority of strains typed in our laboratory. Overall, the results demonstrate an increasing number of C. difficile strains resistant to fluoroquinolones in Italy and changes in the prevalence and type of C. difficile isolates resistant to fluoroquinolones circulating over time.

Human intestinal microbiota gene risk factors for antibiotic-associated diarrhea: perspectives for prevention. Risk factors for antibiotic-associated diarrhea

Antibiotic-associated diarrhea (AAD) is associated with altered intestinal microflora and other symptoms that may lead to possibly death. In critically ill patients, diarrhea increases rates of morbimortality. Assessing diarrhea risks is thus important for clinicians. For this reason, we conducted a hypothesis-generating study focused on AAD to provide insight into methods of prevention. We evaluated the hypothesis of predisposing factors within the resident intestinal microbiota in a cohort of outpatients receiving antibiotherapy. Among the pool of tested variables, only those related to bacterial 16S rRNA genes were found to be relevant. Complex statistical analyses provided further information: amid the bacteria 16S rRNA genes, eight were determined to be essential for diarrhea predisposition and characterized from the most important to the least. Using these markers, AAD risk could be estimated with an error of 2%. This molecular analysis offers new perspectives for clinical applications at the level of prevention.

Diarréia nosocomial em unidade de terapia intensiva: incidência e fatores de risco

RACIONAL: Diarréia nosocomial parece ser comum em unidades de terapia intensiva, embora sua epidemiologia seja pouco documentada em nosso meio. OBJETIVO: Determinar a incidência e fatores de risco de diarréia entre pacientes adultos internados em unidade de terapia intensiva. MÉTODOS: Foram incluídos prospectivamente 457 pacientes no período entre outubro de 2005 e outubro de 2006. Dados demográficos, clínicos e bioquímicos, bem como aspecto e número de evacuações eram registrados diariamente até a saída do paciente do setor. RESULTADOS: Diarréia ocorreu em 135 (29,5%) pacientes, durando em média 5,4 dias. O tempo do seu início em relação à internação foi de 17,8 dias e casos similares de diarréia no mesmo período foram registrados em 113 (83,7%) pacientes. A mortalidade hospitalar foi maior nos pacientes com diarréia do que naqueles sem esta intercorrência. Na análise multivariada através de modelo de regressão logística, apenas o número de antibióticos (OR 1,65; IC 95% = 1,39-1,95) e o número de dias de antibioticoterapia (OR 1,16; IC 95% = 1,12-1,20) associaram-se estatisticamente com a ocorrência de diarréia. Cada dia de acréscimo a mais da antibioticoterapia aumentou em 16% o risco de diarréia (IC 12% a 20%), enquanto a adição de um antibiótico a mais ao esquema antimicrobiano aumentou as chances de ocorrência de diarréia em 65% (IC 39% a 95%). CONCLUSÃO: A incidência de diarréia nosocomial na unidade de terapia intensiva é elevada (29,5%). Os principais fatores de risco para sua ocorrência foram número de antibióticos prescritos e duração da antibioticoterapia. Além das precauções entéricas, a prescrição judiciosa e limitada de antimicrobianos, provavelmente reduzirá a ocorrência de diarréia neste setor.

Increasing seroprevalence of Clostridium difficile in an adult Danish general population

The incidence of Clostridium difficile-associated infections is increasing, but it remains to be defined whether any change in the seroprevalence of C. difficile has also occurred. In a population-based study of the general adult population, 734 subjects, aged 15-69 years, were examined on two occasions 8 years apart (1990 and 1998) for the presence of antibodies against C. difficile in serum. The overall seroprevalence of C. difficile increased significantly from 19% in 1990 to 27% in 1998 (P<0.0001). The seroprevalence increased with increasing age in both 1990 and 1998, but the increase was about four times higher in 1998 than in 1990. In conclusion, the observed increase in seroprevalence suggests a higher exposure to C. difficile in the general Danish adult population.

Detection of a Genetic Linkage Between Genes Coding for Resistance to Tetracycline and Erythromycin inClostridium difficile

Elements carrying more than one antibiotic resistance gene have never been found in Clostridium difficile, one of the major causes of nosocomial diarrheic diseases. In this study, C. difficile isolates were investigated for a possible genetic linkage between tet(M) and erm(B), the most frequent genes found in strains resistant to tetracycline and erythromycin. In the majority of C. difficile strains, tet(M) is carried by Tn5397. However, tet(M) genes carried by Tn916-like elements have been found in recent clinical isolates. As far as erythromycin resistance is concerned, the only completely characterized transposon harboring an erm(B) gene in C. difficile is Tn5398, even if ErmB determinants probably carried by other elements have been identified. Among the 100 C. difficile isolates screened in this study, 27 were positive for tet(M) and erm(B). Twenty five of these strains were positive for tndX, used as marker for Tn5397, whereas two were positive for int, used as marker for Tn916-like elements. The latter isolates showed two tet(M) genes: one was carried by a Tn916-like element, able to transfer to a recipient C. difficile strain, whereas the second was genetically linked to an erm(B) in a composite element probably unable to conjugate. Molecular analysis of C. difficile cd1911 tet(M)-erm(B) DNA sequence demonstrated that this region has arisen by recombination of DNA fragments from different plasmids and transposons. This is the first demonstration that C. difficile is able to accumulate and maintain antibiotic resistance genes, as observed in other pathogens.

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Prolonged ileus as a sole manifestation of pseudomembranous enterocolitis

BACKGROUND

Pseudomembranous colitis usually manifests as fever and diarrhea in hospitalized patients treated with systemic antibiotics. We present a case that represents a unique variant.

CASE PRESENTATION

The 44-year-old man suffered of several weeks of abdominal pain, low-grade fever, nausea, vomiting, and lack of bowel movements. Upper gastrointestinal barium swallow and passage series revealed evidence of severe intestinal hypomotility. A thorough evaluation for the cause of the patient's ileus and abdominal pain was unrevealing, and symptomatic treatment was ineffective. Following the administration of opiates and dietary fiber supplementation the patient's abdominal pain and distention rapidly worsened, requiring an urgent subtotal colectomy. The macroscopic and microscopic appearance of the excised colon as well as results of the colonic cytotoxin essay and fecal enzyme-linked immunosorbent assay essay confirmed the diagnosis of severe Clostridium difficile induced pseudomembranous colitis as the cause of the patient's illness.

CONCLUSION

To our knowledge, this is the first reported case of Clostridium-difficile induced disease consisting of prolonged ileus in the absence of diarrhea in a patient not previously taking antibiotics.

Boswell Award of the SAVA: 1991. Dr. D. G. Catton

Colonic diverticula are protrusions of the mucosa through the outer muscular layers, which are usually abnormally thickened, to form narrow necked pouches. Diverticular disease of the colon covers a wide clinical spectrum: from an incidental finding to symptomatic uncomplicated disease to diverticulitis. A quarter of patients with diverticulitis will develop potentially life-threatening complications including perforation, fistulae, obstruction or stricture. In Western countries diverticular disease predominantly affects the left colon, its prevalence increases with age and its causation has been linked to a low dietary fibre intake. Right-sided diverticular disease is more commonly seen in Asian populations and affects younger patients. Its pathogenesis and relationship to left-sided diverticular disease remains unclear. Diverticular disease of the colon is a significant cause of morbidity and mortality in the Western world and its frequency has increased throughout the whole of the 20th century. Since it is a disease of the elderly, and with an aging population, it can be expected to occupy an increasing portion of the surgical and gastroenterological workload. It is uncertain what symptoms uncomplicated diverticular disease gives rise to: there is an overlap with irritable bowel syndrome. Diagnosis is primarily by barium enema and colonoscopy, but more sophisticated imaging procedures such as computed tomography (CT) are increasingly being used to assess and treat complications such as abscess or fistula, or to provide alternative diagnoses if diverticulosis is not confirmed. Initial therapy for uncomplicated diverticulitis is supportive, including monitoring, bowel rest and antibacterials. CT is used to guide percutaneous drainage of abscesses to avoid surgery or allow it to be performed as an elective procedure. Surgery is indicated for complications of acute diverticulitis, including failure of medical treatment, gross perforation, and abscess formation that cannot be resolved by percutaneous drainage. Complications of chronic diverticulitis (fistula formation, stricture and obstruction) are also usually treated surgically. However, the indications for, and the timing and staging of operations for diverticular disease are often difficult decisions requiring sound clinical judgement. Factors such as the number of episodes of inflammation, the age of the patient, and his/her overall medical condition play a role in determining whether or not a patient should undergo surgical resection. Laparoscopic surgery may be associated with less pain, less morbidity and shorter hospital stays, but its exact role is yet to be defined. Diverticular disease of the colon is the most common cause of acute lower gastrointestinal haemorrhage, which can be massive. Although the majority of patients stop bleeding spontaneously, angiographic and surgical treatment may be required, while the place of endoscopic haemostasis remains to be established.