Clostridium difficile infection in cancer patients with hospital acquired diarrhea at the teaching hospitals in Iran: Multilocus sequence typing analysis (MLST) and Antimicrobial resistance pattern

BACKGROUND

This study aimed to investigate the phenotype and genotype characterization of Clostridium difficile isolates among cancer patients with hospital-acquired diarrhea in 4 teaching hospitals in Isfahan, Iran.

STUDY DESIGN

This was a cross sectional study conducted on adult (>18 years old) between April 2015 and May 2017.

METHODS

Over two years, 67 diarrheic fecal samples were collected. C. difficile isolates were characterized according to the presence of toxin genes and antibiotic resistance. Multilocus sequence typing (MLST) was performed to evaluate the genetic relationships between different lineages of toxigenic strains.

RESULTS

Seven toxigenic and 12 non- toxigenic strains were detected among stool samples. Patients with a history of previous surgery during hospitalization were more than 7 times likely to develop Clostridium difficile infection (CDI). All isolates were susceptible to metronidazole, vancomycin and fusidic acid. Toxigenic C. difficile strains were divided into 3 different sequence types. The detected types were ST-54, ST-2 and ST-37, while none of the isolates was identified as ST-1 or ST-11.

CONCLUSIONS

This is the first description of the MLST analysis of C. difficile strains isolated from cancer patients in Iran. All of the studied population were exposed to multiple antibiotics and chemotherapeutic agents. Further research and clinical studies are recommended in the treatment through good antimicrobial stewardship and prevention of C. difficile infection in all healthcare settings.

Surpass Streamline Flow-Diverter Embolization Device for Treatment of Iatrogenic and Traumatic Internal Carotid Artery Injuries

Iatrogenic and traumatic cerebral internal carotid artery injuries are uncommon but potentially lethal complications. Direct surgical repair of ICA injuries may be difficult in an acute setting. However, endovascular treatment with a flow-diverter embolization device is a feasible alternative technique that we experienced. In this clinical report, we describe demographic data, radiographic images, lesion characteristics, endovascular procedure notes, postprocedural hospital course, and follow-up digital subtraction angiography of 5 patients. At least 6-month follow-up was available in all patients without occurrence of rebleeding and other complications.

Mycobacterium arupense infection in HIV-infected patients from Iran

Here we report two cases of infection caused by Mycobacterium arupense in HIV-infected patients who had received Mycobacterium avium complex medication after primary treatment with antituberculous drugs. The causative agents were isolated from the respiratory and blood specimens of the patients. The identification was based on conventional and molecular tests. Our study provides further evidence on the role of this microorganism in clinical cases.

Molecular microbiological investigation of post-vaccination bacille Calmette-Guérin infection in Iranian patients

BACKGROUND

The World Health Organization (WHO) has called for closer monitoring of bacille Calmette-Guérin (BCG) complications with specific efforts to distinguish BCG infection from tuberculosis.

OBJECTIVES

To detect the presence of BCG infection using clinical and microbiological approaches.

STUDY DESIGN

Between 2006 and 2008, 32 cases, including 30 children with suspected BCG-related complications and two adults with local skin infections, were referred to our laboratory. The definitive identification of the isolates was based on phenotypic and molecular testing. The genotype profile of the isolates was determined to evaluate the relatedness of the cases.

RESULTS

Molecular microbiological results confirmed the presence of infection due to Mycobacterium bovis BCG in 11 patients, of whom 9 were aged 2 months to 6 years and 2 were aged > 40 years. Molecular fingerprinting revealed that all isolates were genetically related to each other and to M. bovis BCG Pasteur 1173P2.

CONCLUSION

A high incidence of adverse reactions to the BCG vaccine in the population studied clearly points to the need for a thorough study on the issue. We hope our study will be viewed as an evidence-based document for more precise risk-benefit evaluation of BCG immunisation in immunocompromised patients.

Lysis of a broad range of epithelial tumour cells by human gamma delta T cells: involvement of NKG2D ligands and T-cell receptor- versus NKG2D-dependent recognition

Human gammadelta T cells expressing a V gamma 9V delta 2 T-cell receptor (TCR) kill various tumour cells including autologous tumours. In addition to TCR-dependent recognition, activation of NKG2D-positive gammadelta T cells by tumour cell-expressed NKG2D ligands can also trigger cytotoxic effector function. In this study, we investigated the involvement of TCR versus NKG2D in tumour cell recognition as a prerequisite to identify tumour types suitable for gammadelta T-cell-based immunotherapy. We have characterized epithelial tumour cells of different origin with respect to cell surface expression of the known NKG2D ligands MHC class I-chain-related antigens (MIC) A/B and UL16-binding proteins (ULBP), and susceptibility to gammadelta T-cell killing. Most tumour cells expressed comparable levels of MICA and MICB as well as ULBP with the exception of ULBP-1 which was absent or only weakly expressed. Most epithelial tumours were susceptible to allogeneic gammadelta T-cell lysis and in the case of an established ovarian carcinoma to autologous gammadelta T-cell killing. Lysis of resistant cells was enhanced by pre-treatment of tumour cells with aminobisphosphonates or pre-activation of gammadelta T cells with phosphoantigens. A potential involvement of TCR and/or NKG2D was investigated by antibody blockade. These experiments revealed three patterns of inhibition, i.e. preferential inhibition by anti-TCR antibody, preferential inhibition by anti-NKG2D antibody, or additive blockade by anti-TCR plus anti-NKG2D antibodies. Our results indicate for the first time that the NKG2D pathway is involved in the lysis of different melanomas, pancreatic adenocarcinomas, squamous cell carcinomas of the head and neck, and lung carcinoma.

Mycobacterium elephantis sp. nov., a rapidly growing non-chromogenic Mycobacterium isolated from an elephant

A strain isolated from a lung abscess in an elephant that died from chronic respiratory disease was found to have properties consistent with its classification in the genus Mycobacterium. An almost complete sequence of the 165 rDNA of the strain was determined following the cloning and sequencing of the amplified gene. The sequence was aligned with those available on mycobacteria and phylogenetic trees inferred by using three tree-making algorithms. The organism, which formed a distinct phyletic line within the evolutionary radiation occupied by rapidly growing mycobacteria, was readily distinguished from members of validly described species of rapidly growing mycobacteria on the basis of its mycolic acid pattern and by a number of other phenotypic features, notably its ability to grow at higher temperatures. The type strain is Mycobacterium elephantis DSM 44368T.

The differentiation of Carnobacterium divergens using the random amplification of polymorphic DNA polymerase chain reaction technique

The potential of the randomly amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) technique to differentiate Carnobacterium divergens from other members of the genus Carnobacterium was examined. A numerical analysis of the genomic profiles obtained demonstrated that it was possible to differentiate the C. divergens strains from other Carnobacterium strains using this technique. The heterogeneity observed in the representatives of the species C. piscicola adds further weight to the suggestion in other taxonomic studies that subspecies of this species exist.

Nocardia, nocardiosis and mycetoma

The recent emergence of invasive infections due to Nocardia spp., including nosocomial outbreak, is now evident. Newer molecular diagnostic and typing methods are developed. Although sulfonamide-based therapy is generally effective, optimal treatment may be guided by antimicrobial susceptibility testing of isolates. The improved classification of nocardiae and other related genera such as actinomadurae, using the 16S ribosomal RNA sequencing, provide a sound basis for improved diagnostic methods for the identification of members of clinically significant species. The commonest cause of eumycetoma in Sudan is Madurella mycetomatis, and Streptomyces somaliensis and Actinomadura madurae for actinomycetoma. The humoral immunity response in actinomycetoma patients and in experimental mice was measured and significant titre of anti-P24 antibody was demonstrated.

Mycobacterium novocastrense sp. nov., a rapidly growing photochromogenic mycobacterium

A strain isolated from a biopsy sample taken from a slowly spreading skin granulation on a child's hand was found to have properties consistent with its classification in the genus Mycobacterium. An almost complete gene sequence of the 16S rRNA of the strain was determined following the cloning and sequencing of the amplified gene. The sequence was aligned with those available for mycobacteria, and phylogenetic trees were inferred with four tree-making algorithms. The organism, which formed a distinct phyletic line within the evolutionary radiation occupied by rapidly growing mycobacteria, was readily distinguished from members of validly described species of rapidly growing mycobacteria on the basis of its mycolic acid pattern and a number of other phenotypic features, notably its ability to form yellow pigmented colonies when incubated in the light. The name proposed for this new species is Mycobacterium novocastrense. The type strain is DSM 44203.