Clostridial infection in children

Bacteremia due to Clostridium innocuum: Analysis of four cases and literature review

Clostridium innocuum is a Gram-positive anaerobic spore-forming bacillus that has been identified as part of the normal intestinal microbiota. This bacterium has been rarely associated with human infections, and only few severe infections have been reported until now. In this work, we report on four patients with bacteremia due to C. innocuum, which were well identified by MALDI-TOF MS. Moreover, a review of the previous published cases of bacteremia due to this anaerobic bacterium has been performed.

Two cases of Clostridium ramosum bacteremia with intestinal perforation: The antimicrobial susceptibility of clinical strains

Clostridium ramosum is one of the obligate anaerobes that constitute the intestinal flora, and one of the rare Clostridia. With Clostridium ramosum, very few data have been reported to investigate antimicrobial susceptibility for clinical isolates that have caused bacteremia. Here, we report two cases of Clostridium ramosum bacteremia. The first case was a 54-year-old Japanese man with taking 20mg hydrocortisone for hypopituitarism. He presented to the emergency department for an unknown cause cardiopulmonary arrest. At the hospital day 36, he had fever and a drop in blood pressure. Abdomen computed tomography (CT) revealed free air around the ascending colon, we diagnosed with intestinal perforation, and peritonitis. Blood culture revealed Clostridium ramosum. We administered conservative management by 6-week of antibiotic treatment. The second case was a 78-year-old Japanese man with no significant medical history. He was referred to our hospital with fever and abdominal pain. Abdomen CT revealed perforated appendicitis, and blood cultures revealed Clostridium ramosum. We performed emergency surgery, and administered one-week course of antibiotic treatment. This report demonstrates two cases of Clostridium ramosum bacteremia with intestinal perforation, and the antimicrobial susceptibility of each clinical strain. For the future, it is necessary to accumulate data on the susceptibility of clinical isolates in order to find an appropriate treatment.

Clostridium innocuum: Microbiological and clinical characteristics of a potential emerging pathogen

Clostridium innocuum is an anaerobic, gram-positive, spore-forming bacterium identified by Smith and King in 1962 after being isolated from a patient with an appendiceal abscess. Its name, C. innocuum, reflected its clinically "innocuous" nature based on observed lack of virulence in animal models of infection. Since that time, C. innocuum has been identified as both part of the normal intestinal flora and the cause of a rare, intrinsically vancomycin-resistant opportunistic infection in immunocompromised patients. More recently, reports from Taiwan suggest that C. innocuum, in addition to being a known extraintestinal pathogen, may also be a diarrheal pathogen that causes a C. difficile infection-like antibiotic-associated diarrheal illness. However, unanswered questions about the clinical relevance of C. innocuum remain. Here we review the microbiological and clinical characteristics of this emerging pathogen.

Antimicrobial treatment of Erysipelatoclostridium ramosum invasive infections: a systematic review

The aim of this systematic review was to determine the causal role of Erysipelatoclostridium ramosum in specific invasive infections in humans, and to assess the clinical outcome of antibiotic therapy used to treat them. Several electronic databases were systematically searched for clinical trials, observational studies or individual cases on patients of any age and gender with a systemic inflammatory response syndrome (SIRS) due to E. ramosum isolated from body fluids or tissues in which it is not normally present. Only reports identifying E. ramosum as the only microorganism isolated from a patient with SIRS were included. This systematic review included 15 studies reporting 19 individual cases in which E. ramosum caused invasive infections in various tissues, mainly in immunocompromised patients. E. ramosum was most often isolated by blood cultures and identified by specific biochemical tests. Severe infections caused by E. ramosum were in most cases effectively treated with antibiotics, except in two patients, one of whom died. More than one isolate of E. ramosum exhibited 100% susceptibility to metronidazole, amoxicillin/clavulanate and piperacillin/tazobactam. On the other hand, individual resistance of this bacterium to penicillin, ciprofloxacin, clindamycin, imipenem and ertapenem was reported. This systematic review confirmed the clinical relevance of E. ramosum as a cause of a number of severe infections mainly in immunocompromised inpatients. Metronidazole and meropenem appear to be the antibiotics of choice that should be used in combination or as monotherapy to treat E. ramosum infections, depending on the type and severity of the infection.

The Depletion of Carbohydrate Metabolic Genes in the Gut Microbiome Contributes to the Transition From Central Obesity to Type 2 Diabetes

Obesity, especially central obesity, is a strong risk factor for developing type 2 diabetes (T2D). However, the mechanism underlying the progression from central obesity to T2D remains unknown. Therefore, we analyzed the gut microbial profiles of central obese individuals with or without T2D from a Chinese population. Here we reported both the microbial compositional and gene functional alterations during the progression from central obesity to T2D. Several opportunistic pathogens were enriched in obese T2D patients. We also characterized thousands of genes involved in sugar and amino acid metabolism whose abundance were significantly depleted in obese T2D group. Moreover, the abundance of those genes was negatively associated with plasma glycemia level and percentage of individuals with impaired plasma glucose status. Therefore, our study indicates that the abundance of those depleted genes can be used as a potential biomarker to identify central obese individuals with high risks of developing T2D.

Rapidly Fatal Postlaparoscopic Liver Infection from the Rarely Isolated Species Clostridium butyricum

We report a case of a rapidly fatal postlaparoscopic cholecystectomy liver infection from the rarely isolated species Clostridium butyricum. Liver examination at autopsy showed cystic spaces, necrosis, and spore-forming Gram-positive rods. 16sRNA gene sequencing of the cystic liver tissue identified the organism as C. butyricum.

Clostridium ramosum rapidly identified by MALDI-TOF MS. A rare gram-variable agent of bacteraemia

Clostridium ramosum is an enteric anaerobic, endospore-forming, gram-positive rod with a low GC content that is rarely associated with disease in humans. We present a case of C. ramosum bacteraemia. To the best of our knowledge, this is the second case of C. ramosum bacteraemia in an elderly patient presenting with fever, abdominal pain and bilious emesis. We highlight the Gram stain variability, the lack of visualization of spores and the atypical morphology of the colonies that showed C. ramosum in a polymicrobial presentation that initially appeared to show monomicrobial bacteraemia. The microorganism was rapidly identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). We present a comprehensive literature review of 32 cases of clinical infections by C. ramosum in which we describe, if available, sex, age, clinical symptoms, predisposing conditions, other organisms present in the blood culture, other samples with C. ramosum , identification methodology, treatment and outcome.

Clostridium Ramosum-A Rare Cause of Peritoneal Dialysis-Related Peritonitis

We present the first report of a patient with peritoneal dialysis (PD)-related peritonitis due to Clostridium ramosum, an anaerobe bacterium that is commonly found in normal fecal flora. On rare occasions, it can be pathogenic in immunocompromised individuals. Clostridium species, including Clostridium ramosum, should be included in the differential diagnosis of PD-related peritonitis.

Genomic Characterization of Sulphite Reducing Bacteria Isolated From the Dairy Production Chain

Anaerobic sporeformers, specifically spoilage and pathogenic members of the genus Clostridium, are a concern for producers of dairy products, and of powdered dairy products in particular. As an alternative to testing for individual species, the traditional, and still current, approach to detecting these sporeformers, including non-spoilage/non-pathogenic species, in dairy products has involved testing for a sulphite reducing phenotype [Sulphite reducing Clostridia (SRCs)] under anaerobic conditions. This phenotype is conserved throughout the Order Clostridia. Unfortunately, however, this phenotype is exhibited by other sulphite reducing bacteria (SRBs) also, potentially leading to potential for false positives. Here, this risk was borne out through the identification of several SRBs from industry samples that were identified as Proteus mirabilis and various Bacillus/Paenibacillus sp. Genome wide comparison of a number of representative SRCs and SRBs was employed to determine phylogenetic relationships, especially among SRCs, and to characterize the genes responsible for the sulphite reducing phenotype. This screen identified two associated operons, i.e., asrABC in SRCs, and cysJI in Bacillus/Paenibacillus spp. and P. mirabilis. This screen identified spp. belonging to sensu stricto, Lachnospiraceae and Cluster XIV of the Clostridia all producing the SRC phenotype. This study highlights the inaccuracy of the industry standard SRC test but highlights the potential to generate an equivalent molecular test designed to detect the genes responsible for this phenotype in clostridia.

Clostridium paraputrificum septicemia and liver abscess

We report the first case of a healthy 23-year-old female who underwent an interventional radiology-guided embolization of a hepatic adenoma, which resulted in a gas forming hepatic liver abscess and septicemia by Clostridium paraputrificum. A retrospective review of Clostridial liver abscesses was performed using a PubMed literature search, and we found 57 clostridial hepatic abscess cases. The two most commonly reported clostridial species are C. perfringens and C. septicum (64.9% and 17.5% respectively). C. perfringens cases carried a mortality of 67.6% with median survival of 11 h, and 70.2% of the C. perfringens cases experienced hemolysis. All C. septicum cases were found to have underlying liver malignancy at the time of the presentation with a mortality of only 30%. The remaining cases were caused by various Clostridium species, and this cohort’s clinical course was significantly milder when compared to the above C. perfringens and C. septicum cohorts.

Preterm Infant-Associated Clostridium tertium, Clostridium cadaveris, and Clostridium paraputrificum Strains: Genomic and Evolutionary Insights

Clostridium species (particularly Clostridium difficile, Clostridium botulinum, Clostridium tetani and Clostridium perfringens) are associated with a range of human and animal diseases. Several other species including Clostridium tertium, Clostridium cadaveris, and Clostridium paraputrificum have also been linked with sporadic human infections, however there is very limited, or in some cases, no genomic information publicly available. Thus, we isolated one C. tertium strain, one C. cadaveris strain and three C. paraputrificum strains from preterm infants residing within neonatal intensive care units and performed Whole Genome Sequencing (WGS) using Illumina HiSeq. In this report, we announce the open availability of the draft genomes: C. tertium LH009, C. cadaveris LH052, C. paraputrificum LH025, C. paraputrificum LH058, and C. paraputrificum LH141. These genomes were checked for contamination in silico to ensure purity, and we confirmed species identity and phylogeny using both 16S rRNA gene sequences (from PCR and in silico) and WGS-based approaches. Average Nucleotide Identity (ANI) was used to differentiate genomes from their closest relatives to further confirm speciation boundaries. We also analysed the genomes for virulence-related factors and antimicrobial resistance genes, and detected presence of tetracycline and methicillin resistance, and potentially harmful enzymes, including multiple phospholipases and toxins. The availability of genomic data in open databases, in tandem with our initial insights into the genomic content and virulence traits of these pathogenic Clostridium species, should enable the scientific community to further investigate the disease-causing mechanisms of these bacteria with a view to enhancing clinical diagnosis and treatment.

Clostridium innocuum is a vancomycin-resistant pathogen that may cause antibiotic-associated diarrhoea

OBJECTIVES

Clostridium innocuum can cause extraintestinal infection in patients with underlying diseases. The role of C. innocuum in antibiotic-associated diarrhoea (AAD) remains unknown.

METHODS

Clinical information of 103 patients from whom C. innocuum was isolated was reviewed. We carried out cellular and animal experiments to examine the pathogenic potential of C. innocuum in AAD.

RESULTS

Eighty-eight per cent (91/103) of the 103 patients received antibiotics within 2 weeks of diarrhoea onset. Patients were further classified into two groups, severe colitis and diarrhoea, according to clinical severity level. The mortality rate was 13.6% (14/103) among the patients from whom C. innocuum was isolated. The lowest concentrations at which 90% of the isolates were inhibited for metronidazole and vancomycin were 0.5 and 16 mg/L, respectively. All isolates tested were susceptible to metronidazole but resistant to vancomycin. Nineteen randomly selected isolates (ten from severe colitis group, nine from diarrhoea group) were subjected to further in vitro cellular examinations. The level of cytotoxicity to Vero cells was significantly higher in isolates from the severe colitis group at both 24 and 48 hours after inoculation (24 and 48 hours, p 0.042 and 0.033, respectively). We observed apoptotic changes that subsequently led to cell death in C. innocuum-infected Vero cells. Tissue damages, necrotic changes and oedema were observed in the mouse ileal loop infected by C. innocuum.

CONCLUSIONS

Vancomycin-resistant C. innocuum may play a potential role as a causative agent of AAD. The clinical manifestations of AAD caused by C. innocuum were diarrhoea or severe colitis, including pseudomembranous colitis.

Gut dysbiosis following C-section instigates higher colonisation of toxigenic Clostridium perfringens in infants

Herein we investigated the intestinal carriage of α-toxigenic and enterotoxigenic Clostridium perfringens during infancy, focusing on its association with other gut microbes and mode of delivery and feeding. Faecal samples from 89 healthy term infants were collected at age 7 days, 1 month, 3 months, 6 months and 3 years. C. perfringens was quantified by qPCR; other gut bacteria were quantified by reverse-transcription-qPCR. Alpha-toxigenic C. perfringens was detected in 3.4% infants at day 7 but was present in 35-40% infants at subsequent time-points, with counts ranging from 10³-10⁷ cells/g faeces. Enterotoxigenic C. perfringens remained undetected at day 7 but was detected in 1.1, 4.5, 10.1 and 4.5% infants at 1 month, 3 months, 6 months and 3 years, respectively. Intriguingly, infants carrying α-toxigenic C. perfringens had lower levels of Bacteroides fragilis group, bifidobacteria, lactobacilli and organic acids as compared to non-carriers. Further analyses revealed that, compared to vaginally-born infants, caesarean-born infants had higher carriage of C. perfringens and lower levels of B. fragilis group, bifidobacteria, lactobacilli and faecal organic acids during first 6 months. Compared to formula-fed infants, breast-fed infants were slightly less often colonised with C. perfringens; and within caesarean-born infants, breast-fed infants had slightly lower levels of C. perfringens and higher levels of B. fragilis group, bifidobacteria, and lactobacilli than formula-fed infants. This study demonstrates the quantitative dynamics of toxigenic C. perfringens colonisation in infants during the early years of life. Caesarean-born infants acquire a somewhat perturbed microbiota, and breast-feeding might be helpful in ameliorating this dysbiosis. Higher carriage of toxigenic C. perfringens in healthy infants is intriguing and warrants further investigation of its sources and clinical significance in infants, particularly the caesarean-born who may represent a potential reservoir of this opportunistic pathogen and might be more prone to associated illnesses.

Abortion and mortality in farm mink (Neovison vison) associated with feed-born Clostridium limosum

Disease in mink clinically characterized by abortion and increased mortality among pregnant female mink on 28 Danish farms was observed during April and May 2015. Most of these farms suffered extensive disease problems, including a significant increase in the number of mated females without litters. Pathological, microbiological and molecular biological methods were applied to investigate the cause of disease. Necropsies of animals found dead revealed fragile and partially dissolved (liquefying) uterine tissue, with the presence of Gram positive rod-shaped bacteria. These slow growing bacteria were isolated by anaerobic culturing and identified as Clostridium limosum by both MALDI-TOF mass spectrometry analysis and 16S rRNA gene sequencing. All the performed tests for relevant differential diagnoses were negative. Foodborne disease was indicated because all the affected farms were served by the same feed factory. A specific PCR-based analysis was developed for positive identification of C. limosum and used to screen archived feed samples from the implicated feed factory. Both C. limosum 16S rRNA genes and C. limosum collagenase genes were identified in both mixed feed and more specifically in raw chicken carcass used as one of the components in the mixed feed, which was therefore identified as the most likely source of contamination. Based on the results of this investigation it is concluded that C. limosum can be associated with abortion and increased mortality in pregnant mink females and it is consequently recommended that raw materials contaminated with C. limosum should be avoided in mink feed, in particular during the whelping season.

Further analysis reveals new gut microbiome markers of type 2 diabetes mellitus

In recent years, metagenome-wide association studies have revealed potential relationships between intestinal microbiomes and the pathogenesis of type 2 diabetes mellitus (T2DM). However, considering the increase in volume of gene catalogues and algorithms, an updated analysis would be expected to confirm previous discoveries and provide new knowledge. We therefore constructed new profiles after mapping the recent catalogue of reference genes in the human gut microbiome to reanalyze samples from T2DM cases and controls in the Chinese population. We identified different compositions between Chinese controls and T2DM patients at the species and genus levels, especially in the case of butyrate-producing bacteria, Haemophilus, and Lactobacillus. An effective metagenomic linkage group random forest model was built to differentiate controls from T2DM cases in different cohorts. Functional markers from the Kyoto Encyclopedia of Genes and Genomes database were identified using new annotations. We also report 16 virulence factor markers and 22 antibiotic resistance markers associated with T2DM.

Sensitive quantification of Clostridium perfringens in human feces by quantitative real-time PCR targeting alpha-toxin and enterotoxin genes

BACKGROUND

Clostridium perfringens is a widespread pathogen, but the precise quantification of this subdominant gut microbe remains difficult due to its low fecal count (particularly in asymptomatic subjects) and also due to the presence of abundant polymerase-inhibitory substances in human feces. Also, information on the intestinal carriage of toxigenic C. perfringens strains in healthy subjects is sparse. Therefore, we developed a sensitive quantitative real-time PCR assays for quantification of C. perfringens in human feces by targeting its α-toxin and enterotoxin genes. To validate the assays, we finally observed the occurrence of α-toxigenic and enterotoxigenic C. perfringens in the fecal microbiota of healthy Japanese infants and young adults.

METHODS

The plc-specific qPCR assay was newly validated, while primers for 16S rRNA and cpe genes were retrieved from literature. The assays were validated for specificity and sensitivity in pre-inoculated fecal samples, and were finally applied to quantify C. perfringens in stool samples from apparently healthy infants (n 124) and young adults (n 221).

RESULTS

The qPCR assays were highly specific and sensitive, with a minimum detection limit of 10(3) bacterial cells/g feces. Alpha-toxigenic C. perfringens was detected in 36% infants and 33% adults, with counts ranging widely (10(3)-10(7) bacterial cells/g). Intriguingly, the mean count of α-toxigenic C. perfringens was significantly higher in infants (6.0±1.5 log10 bacterial cells/g), as compared to that in adults (4.8±1.2). Moreover, the prevalence of enterotoxigenic C. perfringens was also found to be significantly higher in infants, as compared to that in adults. The mean enterotoxigenic C. perfringens count was 5.9±1.9 and 4.8±0.8 log10 bacterial cells/g in infants and adults, respectively.

CONCLUSIONS

These data indicate that some healthy infants and young adults carry α-toxigenic and enterotoxigenic C. perfringens at significant levels, and may be predisposed to related diseases. Thus, high fecal carriage of toxigenic C. perfringens in healthy children warrants further investigation on its potential sources and clinical significance in these subjects. In summary, we present a novel qPCR assay for sensitive and accurate quantification of α-toxigenic and enterotoxigenic C. perfringens in human feces, which should facilitate prospective studies of the gut microbiota.

Clostridial Infections in Children: Spectrum and Management

Clostridia can cause unique histotoxic syndromes produced by specific toxins (e.g., gas gangrene and food poisoning) as well as non-syndromic infections (e.g., abscess, local infections, and blood born infection). Clostridia can also be recovered from various body sites as part of polymicrobial aerobic-anaerobic infection. These include intra-abdominal (peritonitis and abscess), biliary tract, female genital tract, abscess (rectal area and oropharyngeal), pleuropulmonary, central nervous system, and skin and soft-tissue infections. Clostridia were recovered from children with bacteremia of gastrointestinal origin, necrotizing enterocolitis, and sickle cell disease. They have also been isolated in acute and chronic otitis media, chronic sinusitis and mastoiditis, peritonsillar abscesses, and neonatal conjunctivitis. Early and aggressive surgical debridement, decompression, and drainage of affected tissues are critical to successful outcome of histotoxic infections. Effective antimicrobials include penicillin, clindamycin, chloramphenicol, third-generation cephalosporins, carbapenems, and vancomycin.

Clostridium perfringens surgical site infection after osteotomy for knee deformity correction in a non-immunocompromised child

BACKGROUND

Clostridium perfringens myonecrosis following an elective surgical procedure in a previously healthy child is a rare incident.

METHODS

Case report and literature review.

RESULTS

A two-year old boy admitted for elective bilateral osteotomies of tibiae was detected to be febrile at day one post-operatively with crepitus felt at his left ankle. An emergency wound debridement was performed followed by a course of antibiotics. Clostridium perfringens was isolated from tissue culture. His wound was later covered with a split-thickness skin graft.

CONCLUSION

Clostridium perfringens infection following a surgical procedure in a healthy child is rare. A high index of suspicion is important to recognize this debilitating infection.

Clostridium ramosum bacteremia: case report and literature review

BACKGROUND

Clostridium ramosum is a common enteric anaerobe but infrequently also a cause of pathologic infection.

METHODS

Case report and literature review.

RESULTS

We reviewed 12 case reports describing infection with C. ramosum. When pathogenic, C. ramosum is cultured most commonly from the inner ear, anaerobic blood samples, or abscesses. Patients with such infections fall into two demographic groups, consisting of young children with ear infections or immunocompromised adults with bacteremia. Resistance of C. ramosum to antibiotics is uncommon.

CONCLUSION

Clostridium ramosum is a common but generally commensal bacterial species. Rarely, it becomes pathogenic in young children or immunosuppressed adults.

A metagenome-wide association study of gut microbiota in type 2 diabetes

Assessment and characterization of gut microbiota has become a major research area in human disease, including type 2 diabetes, the most prevalent endocrine disease worldwide. To carry out analysis on gut microbial content in patients with type 2 diabetes, we developed a protocol for a metagenome-wide association study (MGWAS) and undertook a two-stage MGWAS based on deep shotgun sequencing of the gut microbial DNA from 345 Chinese individuals. We identified and validated approximately 60,000 type-2-diabetes-associated markers and established the concept of a metagenomic linkage group, enabling taxonomic species-level analyses. MGWAS analysis showed that patients with type 2 diabetes were characterized by a moderate degree of gut microbial dysbiosis, a decrease in the abundance of some universal butyrate-producing bacteria and an increase in various opportunistic pathogens, as well as an enrichment of other microbial functions conferring sulphate reduction and oxidative stress resistance. An analysis of 23 additional individuals demonstrated that these gut microbial markers might be useful for classifying type 2 diabetes.

Clostridia in premature neonates' gut: incidence, antibiotic susceptibility, and perinatal determinants influencing colonization

BACKGROUND

Although premature neonates (PN) gut microbiota has been studied, data about gut clostridial colonization in PN are scarce. Few studies have reported clostridia colonization in PN whereas Bacteroides and bifidobacteria have been seldom isolated. Such aberrant gut microbiota has been suggested to be a risk factor for the development of intestinal infections. Besides, PN are often treated by broad spectrum antibiotics, but little is known about how antibiotics can influence clostridial colonization based on their susceptibility patterns. The aim of this study was to report the distribution of Clostridium species isolated in feces from PN and to determine their antimicrobial susceptibility patterns. Additionally, clostridial colonization perinatal determinants were analyzed.

RESULTS

Of the 76 PN followed until hospital discharge in three French neonatal intensive care units (NICUs), 79% were colonized by clostridia. Clostridium sp. colonization, with a high diversity of species, increased throughout the hospitalization. Antibiotic courses had no effect on the clostridial colonization incidence although strains were found susceptible (except C. difficile) to anti-anaerobe molecules tested. However, levels of colonization were decreased by either antenatal or neonatal (during more than 10 days) antibiotic courses (p = 0.006 and p = 0.001, respectively). Besides, incidence of colonization was depending on the NICU (p = 0.048).

CONCLUSION

This study shows that clostridia are part of the PN gut microbiota. It provides for the first time information on the status of clostridia antimicrobial susceptibility in PN showing that strains were susceptible to most antibiotic molecules. Thus, the high prevalence of this genus is not linked to a high degree of resistance to antimicrobial agents or to the use of antibiotics in NICUs. The main perinatal determinant influencing PN clostridia colonization appears to be the NICU environment.

Modulation of bacterial translocation in mice mediated through lactose and human milk oligosaccharides

Massive resection of the small intestine in infants is imposed to the regulation of several intestinal pathological situations, as intestinal adaptation cannot be relied upon. Many nutritional disturbances are occurring following surgery procedure. In this vein, long-term parenteral feeding is adopt to improve prognosis not always successfully. Clostridia and more specifically Clostridium perfringens, are suspected to participate in the physiopathology of the rising situation. In order to investigate the effect of lactose and human milk neutral oligosaccharides (HMNOs) on Clostridia, germfree mice were inoculated either with enterotoxigenic C.perfringens strain isolated from a patient with NEC, or with a human microbiota harboring C.clostridioforme group(HF). In this vein, different doses of lactose were administrated during 2 weeks in adult mice on an attempt to evaluate the lactase activity. Intake of lactose (70 g/L) and HMNOs (7 g/L) in C.perfringens monoassociated mice induced mortality within a week. In HF mice, no mortality was observed. An increase in Clostridia occurrence was observed in the median ileum after intake of 7 g lactose (p = 0.017). Higher clostridial numbers occurred in caecum following intake of 70 g lactose (p < 0.05) and HMNOs (p < 0.025). Bifidobacteria were found increased from distal ileum to colon following 70 g of lactose intake, whereas they decreased in the caecum of mice drinking lower lactose concentrations. Finally, bacteremia was more frequent in 70 g lactose/L mice (p < 0.02), whereas at lower doses of lactose bifidobacterial translocation was observed. As a result, human milk oligosaccharides could favor clostridial population when reaching the lower intestine. The shortness of the small intestine in infants underwent massive intestinal resection seems to be associated to an incomplete breakdown of lactose. Enteral feeds formulas deprived in lactose would be more suitable in enteral feeding of infants.

Spore-forming Bacilli and Clostridia in human disease

Many Gram-positive spore-forming bacteria in the Firmicute phylum are important members of the human commensal microbiota, which, in rare cases, cause opportunistic infections. Other spore-formers, however, have evolved to become dedicated pathogens that can cause a striking variety of diseases. Despite variations in disease presentation, the etiologic agent is often the spore, with bacterially produced toxins playing a central role in the pathophysiology of infection. This review will focus on the specific diseases caused by spores of the Clostridia and Bacilli.

Selective growth inhibitory effect of biochanin A against intestinal tract colonizing bacteria

Both bifidobacteria and clostridia are part of the natural gut microflora and while clostridia may be responsible for severe intestinal infections, bifidobacteria are probiotic microorganisms belonging to the most important prospective bacteria in the bowel. The antimicrobial activity of biochanin A was tested in vitro against six Bifidobacterium spp., and eight Clostridium spp. using the broth microdilution method. Biochanin A showed an inhibition against all clostridia in the range of minimum inhibitory concentrations (MIC) from 64 microg/mL (for Cl. clostridioforme, strains DSM 933 and I3) to 1,024 microg/mL (for Cl. perfringens, DSM 11778). No bifidobacteria were suppressed at four-fold higher concentration (MICs > 4,096) than MIC of Cl. perfringens. These results indicate selective growth inhibition of biochanin A and its potential use in antimicrobial prevention and/or protection.

Clostridium butyricum sepsis in an injection drug user with an indwelling central venous catheter

Clostridium novyi has been associated with a large outbreak of severe infections in injection drug users. A case of bacteraemia with Clostridium butyricum in an injection drug user is reported. During treatment for Staphylococcus aureus osteomyelitis, the patient used an indwelling central venous catheter to inject cocaine. He was admitted with C. butyricum sepsis that responded to broad spectrum antibiotics, including vancomycin. Local investigation for other cases was unrevealing; however, growth of an unusual pathogen in clinical specimens should be investigated as it may represent a sentinel event with public health implications.

First isolation of Clostridium amygdalinum from a patient with chronic osteitis

We describe a case of osteitis caused by a new and unusual Clostridium species, Clostridium amygdalinum, an environmental, moderately thermophilic bacterium. This is the first documented report of human infection caused by this organism.

Detection and quantification of four species of the genus Clostridium in infant feces

To determine the composition of Clostridium in the feces of infants approximately 30 days old, we have developed a detection and quantification method of Clostridium paraputrificum, Clostridium perfringens, Clostridium tertium, and Clostridium difficile by species-specific primers. C. perfringens and C. difficile were detected in four fecal samples from 22 infants (18.2%), whereas C. paraputrificum was detected in three samples (16.7%). C. tertium was detected in two samples (9.1%). Moreover, the occurrences of the four species in bottle-and mix-fed infants were relatively higher than in breast-fed infants (P< 0.05). Subsequently, positive samples detected by nested PCR (polymerase chain reaction) were subjected to realtime PCR. The results showed that the numbers of C. paraputrificum, C. perfringens, C. tertium, and C. difficile ranged from about 1x10(5) to 3x10(7) cells/g wet feces.

Bacterial contamination of nonsterile disposable gloves before use

BACKGROUND

After Bacillus cereus recovery in opened boxes of disposable gloves, the bacteriological contamination of disposable nonsterile gloves kept stored in native packages was investigated prospectively.

METHODS

Thirty-six commercially available nonsterile nonpowdered disposable gloves made of latex, vinyl, or nitrile were cultured.

RESULTS

A large variety of spore-forming and non-spore-forming bacteria was recovered, including Bacillus cereus and Clostridium perfringens.

CONCLUSION

This finding must be taken into consideration for care involving gloves in very immunocompromised patients.

Differences between the gut microflora of children with autistic spectrum disorders and that of healthy children

Children with autistic spectrum disorders (ASDs) tend to suffer from severe gastrointestinal problems. Such symptoms may be due to a disruption of the indigenous gut flora promoting the overgrowth of potentially pathogenic micro-organisms. The faecal flora of patients with ASDs was studied and compared with those of two control groups (healthy siblings and unrelated healthy children). Faecal bacterial populations were assessed through the use of a culture-independent technique, fluorescence in situ hybridization, using oligonucleotide probes targeting predominant components of the gut flora. The faecal flora of ASD patients contained a higher incidence of the Clostridium histolyticum group (Clostridium clusters I and II) of bacteria than that of healthy children. However, the non-autistic sibling group had an intermediate level of the C. histolyticum group, which was not significantly different from either of the other subject groups. Members of the C. histolyticum group are recognized toxin-producers and may contribute towards gut dysfunction, with their metabolic products also exerting systemic effects. Strategies to reduce clostridial population levels harboured by ASD patients or to improve their gut microflora profile through dietary modulation may help to alleviate gut disorders common in such patients.

Spondylodiscitis due to Clostridium ramosum infection in an immunocompetent elderly patient

The first ever case of spondylodiscitis caused by Clostridium ramosum in an elderly immunocompetent patient has been reported. C. ramosum is usually an intestinal bacterium but may occasionally be isolated in clinical specimens as an opportunistic pathogen. This report shows that this anaerobic organism can cause bone tropism without there having been any contamination due to spinal surgery. The infection cleared after empirical therapy using intravenous amoxicillin and oral metronidazole.

Bacterial superinfection in human tungiasis

Tungiasis is caused by penetration of the female sand flea Tunga penetrans into the epidermis of its host. It is endemic in many countries in Latin America, the Caribbean and sub-Saharan Africa. Although superinfection is a common clinical observation, the frequency and the pattern of bacterial pathogens associated with tungiasis have never been investigated systematically. We conducted a prospective clinico-bacteriological study with patients living in a shantytown in Fortaleza, capital of Ceará State (Northeast Brazil), where tungiasis is hyperendemic. Swabs were taken from 78 patients with multiple lesions after surgical extraction of the parasite, and the specimens were cultured for aerobic and anaerobic microorganisms. Ninety-nine specimens were investigated for aerobic bacteria, from which 146 pathogens were identified. The most common species were Staphyloccous aureus (35.5%) and various enterobacteriaceae (29.5%). Bacillus sp., Enteroccous faecalis, Streptococcus pyogenes and Pseudomonas sp. were also isolated. Eighty-four anaerobic cultures yielded 20 pathogens: in eight cases we detected Peptostreptococcus sp., in seven cases Clostridium sp., and in five cases non-identifiable gram-negative bacilli. These results show that secondary infection is very common in tungiasis, and caused by a variety of highly pathogenic microorganisms. It is proposed that T. penetrans acts as a foreign body facilitating biofilm formation within the epidermis. To prevent spreading of pathogens to the surrounding tissue and/or the systemic circulation, sand fleas should be surgically extracted immediately after penetration.

The Clostridium ramosum IgA proteinase represents a novel type of metalloendopeptidase

Clostridium ramosum is part of the normal flora in the human intestine. Some strains produce an IgA proteinase that specifically cleaves human IgA1 and the IgA2m(1) allotype. This prolylendopeptidase was purified from a broth culture supernatant, and N-terminal sequences of the native protein and tryptic fragments thereof were determined. A fragment of the iga gene encoding the IgA proteinase was isolated using degenerate primers in PCR, and the complete gene was obtained by inverse PCR. The identity of the iga gene was confirmed by heterologous expression in Escherichia coli. The deduced amino acid sequence indicated a signal peptide of 30 residues and a secreted proteinase of 133,828 Da. A typical Gram-positive cell wall anchor motif was identified in the C terminus. The presence of a putative zinc-binding motif His-Glu-Phe-Gly-His together with inhibition studies indicate that the proteinase belongs to the zinc-dependent metalloproteinases. However, the sequence of the C. ramosum IgA proteinase shows no overall similarity to other proteins except for significant identity around the zinc-binding motif with family M6 of metalloendopeptidases, and the unique sequence of the IgA proteinase in this area presumably establishes a new subfamily. The GC percentage of the iga gene is significantly higher than that for the entire genome of C. ramosum, suggesting that the gene was acquired recently in evolution.

Acute necrotizing bacterial tonsillitis with Clostridium perfringens

Bacterial infection with Clostridium perfringens in children less than 2 years of age is frequently associated with meningitis, necrotizing gastrointestinal infection, and postoperative infections. However, a review of the literature reveals no reports of these bacteria infecting the tonsils. A 9-month old black female was found unresponsive at the baby-sitter's and was rushed to the hospital. Shortly after admission to the emergency department death was pronounced. An autopsy performed on this otherwise healthy infant revealed shock and acute necrotizing bacterial tonsillitis. The initial report of this infant's death was questionable sudden infant death syndrome and questionable smothering. Postmortem cerebrospinal fluid, blood, and lung cultures grew pure colonies of C. perfringens. The necrotizing tonsil revealed no significant gross lesions. Microscopically, large numbers of gram-positive rods were easily recognized and were compatible with C. perfringens. Because the oropharynx is a common portal of entry for infectious agents, it is essential to sample tissues of Waldeyer's ring and especially the tonsils to find infectious diseases that may become systemic.

Extraintestinal Clostridium difficile: 10 years' experience at a tertiary-care hospital

OBJECTIVE

To determine the clinical characteristics of patients with extraintestinal Clostridium difficile (ECD).

MATERIAL AND METHODS

All cultures obtained during a 10.5-year period (from Jan. 1, 1985, to Jun. 30, 1995) at a tertiary-care hospital were retrospectively examined. The medical records of patients from whom ECD was isolated were then reviewed.

RESULTS

Fourteen patients from whom ECD was cultured were identified. Thirteen of these patients (93%) had underlying systemic disease. All but one patient had recent exposure to antibiotics, and all had major bowel pathologic conditions. Nine patients had colon perforation. Of the eight patients in whom the colonic mucosa was directly inspected at operation or endoscopy, only two had evidence of pseudomembranous colitis. Five patients (36%) had documentation of recent diarrhea. ECD was isolated from intraperitoneal sites (in nine patients), blood cultures (in three), a perianal abscess, and a prosthetic hip joint. In 13 patients (93%), the infection was polymicrobial. Seven of the 13 inpatients (54%) survived to dismissal.

CONCLUSION

C. difficile is a rare isolate outside of the gastrointestinal tract. ECD is found in patients with systemic illness who have been hospitalized (usually for an extended period), have intestinal pathologic conditions, and have received antibiotics. The isolation of ECD portends a poor prognosis.

Clostridial infection in children

A survey of the isolation of Clostridium spp. from 1543 specimens sent to anaerobic microbiology laboratories revealed 113 isolates from 107 specimens (7.0% of all specimens) from 96 children. The isolates comprised 43 (38%) unidentified Clostridium spp., 37 (33%) C. perfringens, 13 (12%) C. ramosum, five (4%) C. innocuum, six (5%) C. botulinum, three (3%) C. difficile, two (2%) C. butyricum, and one isolate each of C. bifermentans, C. clostridiiforme, C. limosum and C. paraputrificum. Most clostridial isolates were from abscesses (38), peritonitis (26), bacteraemia (10), and chronic otitis media (7). Predisposing or underlying conditions were present in 31 (32%) cases. These were immunodeficiency (12), malignancy (9), diabetes (7), trauma (7), presence of a foreign body (6) and previous surgery (6). The clostridia were the only bacterial isolates in 14 (15%) cases; 82 (85%) cases had mixed infection. The species most commonly isolated with clostridia were anaerobic cocci (57); Bacteroides spp. (B. fragilis group) (50), Escherichia coli (22), pigmented Prevotella or Porphyromonas spp. (18) and Fusobacterium spp. (10). Most Bacteroides and Escherichia coli isolates with clostridia were from abdominal infections and skin and soft tissue infections adjacent to the rectal area; most pigmented Prevotella and Porphyromonas isolates were from oropharyngeal, pulmonary, and head and neck sites. Antimicrobial therapy was given to all patients, in conjunction with surgical drainage in 34 (35%). Only two patients died. These data illustrate the importance of Clostridium spp. in paediatric infections.