Respiratory infection by Corynebacterium striatum: epidemiological and clinical determinants

Isolation and identification of a novel phage targeting clinical multidrug-resistant Corynebacterium striatum isolates

Introduction

Over the past decade, Corynebacterium striatum (C. striatum), an emerging multidrug-resistant (MDR) pathogen, has significantly challenged healthcare settings, especially those involving individuals with weakened immune systems. The rise of these superbugs necessitates innovative solutions.

Methods

This study aimed to isolate and characterize bacteriophages targeting MDR-C. striatum. Utilizing 54 MDR-C. striatum isolates from a local hospital as target strains, samples were collected from restroom puddles for phage screening. Dot Plaque and Double-layer plate Assays were employed for screening.

Results

A novel temperate bacteriophage, named CSP1, was identified through a series of procedures, including purification, genome extraction, sequencing, and one-step growth curves. CSP1 possesses a 39,752 base pair circular double-stranded DNA genome with HK97-like structural proteins and potential for site-specific recombination. It represents a new species within the unclassified Caudoviricetes class, as supported by transmission electron microscopy, genomic evolutionary analysis, and collinearity studies. Notably, CSP1 infected and lysed 21 clinical MDR-C. striatum isolates, demonstrating a wide host range. The phage remained stable in conditions ranging from -40 to 55°C, pH 4 to 12, and in 0.9% NaCl buffer, showing no cytotoxicity.

Discussion

The identification of CSP1 as the first phage targeting clinical C. striatum strains opens new possibilities in bacteriophage therapy research, and the development of diagnostic and therapeutic tools against pathogenic bacteria.

A case report: Severe disseminated infection caused by Strongyloides stercoralis in an immunocompromised patient by metagenomic next-generation sequencing

Background

Strongyloides stercoralis (S. stercoralis) is a nematode that is widely distributed in the tropical and subtropical regions of the world and which can cause severe disseminated infection in immunocompromised individuals. However, strongyloidiasis, the disease caused by S. stercoralis, is difficult to diagnose because of its non-specific clinical presentation and the inadequate performance of conventional diagnostic methods.

Case description

We report the case of a 75-year-old male patient with severe disseminated infection caused by S. stercoralis. The patient had a medical history of seasonal bronchitis and, as a consequence, had taken prednisone for many years. Initial clinical tests failed to detect any pathogens, but metagenomic next-generation sequencing (mNGS) resulted in the identification of S. stercoralis in the patient's bronchoalveolar lavage fluid (BALF) and blood. Subsequently, routine testing repeatedly detected nematode larvae in the patient's stool and sputum. Through a combination of mNGS results and clinical symptoms, the patient was finally diagnosed with severe disseminated infection caused by S. stercoralis.

Conclusion

The clinical manifestations of disease caused by infection with S. stercoralis are not specific; therefore, early and accurate diagnosis is very important. mNGS can detect S. stercoralis even when it is present at only a low level. This case report supports the notion that mNGS is a valuable tool in the diagnosis of severe disseminated infections caused by S. stercoralis in immunocompromised patients.

Targeted Antibiotics for Lower Respiratory Tract Infection with Corynebacterium striatum

Purpose

To assess the impact of targeted antibiotic therapy on clinical outcomes of patients with lower respiratory tract (LRT) infection with Corynebacterium striatum (C. striatum).

Methods

A new propensity score-inverse probability of treatment weighting (IPTW) cohort study was conducted by using 10-year data. The study included LRT infection patients with respiratory secretions cultured positive for C. striatum simultaneously. The primary outcome was all-cause hospital mortality; the secondary outcomes included hospital stay, ICU stay and ventilation time. The safety outcomes were drug-related serum creatinine (Cr) increase and thrombocytopenia.

Results

A total of 339 patients were included in the cohort, and 84 (24.78%) initiated vancomycin or linezolid therapy. In the new IPTW cohort, targeted antibiotic therapy did not improve all-cause hospital mortality (P=0.632), and the OR (95% CI) was 0.879 (0.519-1.488). Moreover, targeted antibiotic therapy was not associated with hospital stay (P=0.415), ICU stay (P=0.945) or ventilation time (P=0.885). The side effects of drug-related higher serum Cr (P=0.044) and thrombocytopenic levels (P=0.038) cannot be ignored.

Conclusion

Clinical benefits by vancomycin or linezolid targeted against LRT infection with C. striatum were limited and with drug-related side effects. A prospectively designed study is needed to further confirm the results.

Gut microbiota composition in COVID-19 hospitalized patients with mild or severe symptoms

Background and aim

COVID-19, the infectious disease caused by SARS-CoV-2 virus that has been causing a severe pandemic worldwide for more than 2 years, is characterized by a high heterogeneity of clinical presentations and evolution and, particularly, by a varying severity of respiratory involvement. This study aimed to analyze the diversity and taxonomic composition of the gut microbiota at hospital admission, in order to evaluate its association with COVID-19 outcome. In particular, the association between gut microbiota and a combination of several clinical covariates was analyzed in order to characterize the bacterial signature associate to mild or severe symptoms during the SARS-CoV-2 infection.

Materials and methods

V3–V4 hypervariable region of 16S rRNA gene sequencing of 97 rectal swabs from a retrospective cohort of COVID-19 hospitalized patients was employed to study the gut microbiota composition. Patients were divided in two groups according to their outcome considering the respiratory supports they needed during hospital stay: (i) group “mild,” including 47 patients with a good prognosis and (ii) group “severe,” including 50 patients who experienced a more severe disease due to severe respiratory distress that required non-invasive or invasive ventilation. Identification of the clusters of bacterial population between patients with mild or severe outcome was assessed by PEnalized LOgistic Regression Analysis (PELORA).

Results

Although no changes for Chao1 and Shannon index were observed between the two groups a significant greater proportion of Campylobacterota and Actinobacteriota at phylum level was found in patients affected by SARS-CoV-2 infection who developed a more severe disease characterized by respiratory distress requiring invasive or non-invasive ventilation. Clusters have been identified with a useful early potential prognostic marker of the disease evolution.

Discussion

Microorganisms residing within the gut of the patients at hospital admission, were able to significantly discriminate the clinical evolution of COVID-19 patients, in particular who will develop mild or severe respiratory involvement. Our data show that patients affected by SARS-CoV-2 with mild or severe symptoms display different gut microbiota profiles which can be exploited as potential prognostic biomarkers paving also the way to new integrative therapeutic approaches.

Identification and Evolutionary Relationship of Corynebacterium striatum Clinical Isolates

Corynebacterium striatum has developed into a new community-acquired and hospital-acquired multi-drug resistance (MDR) bacterium, and is a potential target pathogen for infection control and antibacterial management projects. In this study, non-duplicate samples of inpatients were collected from a local central hospital. Mass spectrometry showed that 54 C. striatum isolates mainly appeared in secretion and sputum from 14 departments. Protein fingerprint cluster analysis showed that the isolates were divided into four groups, most of which appeared in summer. The drug resistance test showed that all strains had multi-drug resistance, with high resistance rates to lincosamides, quinolones and tetracycline detected. Further analysis of the phylogenetic tree of C. striatum was conducted by cloning the 16S rRNA gene. It was found that isolates in the same department had high homology and tended to be located in the same branch or to be crossed in the same main branch. The strains in the same evolutionary branch group had the same drug resistance. Screening of site-specific recombinant elements revealed that 18 strains had integrase genes with the same sequence. This study shows that there may be mobile genetic elements in clinical isolates that drive gene exchange among strains, thus causing the cross-infection, spread and evolution of pathogenic bacteria in the hospital.

Intestinal Flora: A Potential Mechanism by Which Yinlai Decoction Treats Lipopolysaccharide-Induced Pneumonia

Background. We intended to explore the mechanism of Yinlai decoction in the treatment of lipopolysaccharide (LPS)-induced pneumonia from the perspective of intestinal flora. Methods. Thirty Sprague–Dawley rats were randomly assigned to the blank control group (N), the pneumonia group (P), and the Yinlai decoction group (PT). The rat pneumonia model was established using LPS inhalation (0.5 mg/mL, 5 mL, 30 min/day, 3 days). Yinlai decoction was administered intragastrically (2 mL/100 g, 3 days). Lung tissue pathology, organ indexes, serum inflammatory factors, tumor necrosis factor-alpha (TNF-α), and intestinal flora changes were measured. Results. Lung tissue inflammation was prevented by Yinlai decoction. IL-6 levels showed a higher tendency to be higher, and IL-12 and TNF-α were significantly higher in the PT group than in the P group. The structure of the intestinal flora in the P differed from that in the N. The relative abundance of 10 out of 12 microflora was significantly higher in the P group than in the N and PT groups. In the PT group, the structure and the distribution of microbial groups were like those of the N group. Conclusions. Yinlai decoction inhibited LPS-induced lung and systemic inflammation in rats and may help the intestinal flora restore equilibrium by inhibiting the colonization of pathogenic bacteria and adjusting the ratio between probiotics and pathogenic bacteria. Intestinal flora may serve as a mediator of Yinlai decoction’s effect on LPS-induced pneumonia.

Non-diphtheriae Corynebacterium species are associated with decreased risk of pneumococcal colonization during infancy

Streptococcus pneumoniae (pneumococcus) is a leading cause of severe infections among children and adults. Interactions between commensal microbes in the upper respiratory tract and S. pneumoniae are poorly described. In this study, we sought to identify interspecies interactions that modify the risk of S. pneumoniae colonization during infancy and to describe development of the upper respiratory microbiome during infancy in a sub-Saharan African setting. We collected nasopharyngeal swabs monthly (0-6 months of age) or bimonthly (6-12 months of age) from 179 mother-infant dyads in Botswana. We used 16S ribosomal RNA gene sequencing to characterize the nasopharyngeal microbiome and identified S. pneumoniae colonization using a species-specific PCR assay. We detect S. pneumoniae colonization in 144 (80%) infants at a median age of 71 days and identify a strong negative association between the relative abundance of the bacterial genera Corynebacterium within the infant nasopharyngeal microbiome and the risk of S. pneumoniae colonization. Using in vitro cultivation experiments, we demonstrate growth inhibition of S. pneumoniae by secreted factors from strains of several Corynebacterium species isolated from these infants. Finally, we demonstrate that antibiotic exposures and the winter season are associated with a decline in the relative abundance of Corynebacterium within the nasopharyngeal microbiome, while breastfeeding is associated with an increase in the Corynebacterium relative abundance. Our findings provide novel insights into the interspecies interactions that contribute to colonization resistance to S. pneumoniae and suggest that the nasopharyngeal microbiome may be a previously unrecognized mechanism by which environmental factors influence the risk of pneumococcal infections during childhood. Moreover, this work lays the foundation for future studies seeking to use targeted manipulation of the nasopharyngeal microbiome to prevent infections caused by S. pneumoniae.

Dysbiosis and structural disruption of the respiratory microbiota in COVID-19 patients with severe and fatal outcomes

The COVID-19 outbreak has caused over three million deaths worldwide. Understanding the pathology of the disease and the factors that drive severe and fatal clinical outcomes is of special relevance. Studying the role of the respiratory microbiota in COVID-19 is especially important as the respiratory microbiota is known to interact with the host immune system, contributing to clinical outcomes in chronic and acute respiratory diseases. Here, we characterized the microbiota in the respiratory tract of patients with mild, severe, or fatal COVID-19, and compared it to healthy controls and patients with non-COVID-19-pneumonia. We comparatively studied the microbial composition, diversity, and microbiota structure between the study groups and correlated the results with clinical data. We found differences in the microbial composition for COVID-19 patients, healthy controls, and non-COVID-19 pneumonia controls. In particular, we detected a high number of potentially opportunistic pathogens associated with severe and fatal levels of the disease. Also, we found higher levels of dysbiosis in the respiratory microbiota of patients with COVID-19 compared to the healthy controls. In addition, we detected differences in diversity structure between the microbiota of patients with mild, severe, and fatal COVID-19, as well as the presence of specific bacteria that correlated with clinical variables associated with increased risk of mortality. In summary, our results demonstrate that increased dysbiosis of the respiratory tract microbiota in patients with COVID-19 along with a continuous loss of microbial complexity structure found in mild to fatal COVID-19 cases may potentially alter clinical outcomes in patients. Taken together, our findings identify the respiratory microbiota as a factor potentially associated with the severity of COVID-19.

Clinical characteristics of Corynebacterium simulans

Corynebacterium simulans was first reported in 2000. Its characteristics such as isolation frequency, specimen types, and antimicrobial susceptibilities are poorly understood, because identification is difficult using conventional methods. We performed a retrospective observational study of 13 and 317 strains of C. simulans and C. striatum, respectively, isolated from consecutive patients at Nagoya University Hospital from January 2017 to December 2018. We analyzed patients' backgrounds, types of specimens, and antimicrobial susceptibilities. Antimicrobial susceptibilities were compared with those of C. striatum. The frequencies of isolation of C. simulans and C. striatum were 3.9% and 96%, respectively. C. simulans was not detected in specimens associated with mucous membranes, such as sputum and secretions from the craniocervical region, which were frequent for C. striatum. C. simulans was mainly detected in the skin (61.5%). All C. simulans isolates were susceptible to anti-MRSA drugs, as well as to numerous other antibiotics, including those that are orally administered. For example, C. simulans was significantly more susceptible to penicillin G, ceftriaxone, and ciprofloxacin than C. striatum (respective susceptibilities: 66.7% vs 5.4%, 50.0% vs 4.0%, 66.7% vs 5.9%). There was no significant difference between meropenem and erythromycin, although susceptibility to each was relatively high (100.0% vs 31.7%, 50.0% vs 11.9%). C. simulans was susceptible to numerous orally administered antibiotics and more susceptible to antimicrobial drugs than C. striatum. C. simulans was detected less frequently than C. striatum and was infrequently detected in specimens associated with mucous membranes. These characteristics will aid the selection of optimal antimicrobial therapies.

Virulence of clinically relevant multidrug resistant Corynebacterium striatum strains and their ability to adhere to human epithelial cells and inert surfaces

Corynebacterium striatum is a nosocomial pathogen which is increasingly associated with serious infections in both immunocompetent and immunocompromised patients. However, little is known about virulence factors and mechanisms that may enhance the establishment and long-term survival of Corynebacterium striatum. in the hospital environment. In this study, we investigated the ability of 22 multidrug-resistant C. striatum clinical isolates to adhere to human epithelial cells and to produce biofilm on polystyrene plates, glass and various tracheostomy tubes. We also tested the virulence of these strains on the nematode Caenorhabditis elegans. They showed good adhesion to epithelial human cells after 180 min of infection. The 22 C. striatum were able to produce biofilms on positively and negatively charged abiotic surfaces at 37 °C. They were also able to infect and to kill Caenorhabditis elegans after 5 days of infection. The virulence condition was associated with the presence of SpaDEF operon encoding pili in all strains. This study provides new insights on virulence mechanisms that may contribute to the persistence of C. striatum in the hospital environment, increasing the probability of causing nosocomial infections.

Resistance to Antiseptics and Disinfectants of Planktonic and Biofilm-Associated Forms of Corynebacterium striatum

Disinfection and antisepsis are of primary importance in controlling nosocomial infections and outbreaks by pathogens expressing multiple resistance to antimicrobial agents (multidrug-resistant [MDR]) used in therapy. Nowadays, infections related to health services (HAIs) due to MDR and multidrug-susceptible (MDS) Corynebacterium striatum should not be underestimated, including patients using invasive medical devices. The virulence potential of C. striatum needs further investigation. Currently, susceptibility profiles of planktonic and/or sessile forms of four C. striatum strains of different pulsed-field gel electrophoresis types were examined as biocides based on the manufacturer's recommendations: 2% glutaraldehyde (GA), 2% peracetic acid (PA), 1% potassium monopersulfate (Virkon^®; VK), 1% sodium hypochlorite (SH), and 70% ethyl alcohol (ET). Time-kill assays using 2% bovine serum albumin (BSA) were performed for evaluation of influence of organic matter on biocides effects. Planktonic forms expressed GA resistance at different levels. C. striatum viability was observed until 2, 4, 20, and 30 min for MDR 2369/II, MDS 1954/IV, MDR 1987/I, and MDS 1961/III strains, respectively. In contrast to GA, the biocides PA, VK24h, SH, and ET had higher effective bacterial mortality. However, storage of VK (48 hr) reduced their biocide activities. Moreover, mature biofilms were produced on abiotic substrates, including steel surfaces. Post-treatment with GA (30 min), survival of sessile forms was ≥100% than planktonic forms of all C. striatum tested strains. Independent of biocides tested, BSA increased the survival of planktonic and sessile forms (p ≤ 0.005). Present data indicated that hospital staff should be aware of dissemination and eradication of HAIs by C. striatum presenting resistance to biocides, including high-level disinfectants, such as GA.

Chronic Corynebacterium striatum Septic Arthritis in a Patient Referred for Total Knee Arthroplasty

Background

While Corynebacterium striatum and other Corynebacterium species were historically considered contaminants, they are recently being identified as pathogens with increasing frequency. Case Summary. We report the case of a 78-year-old gentleman with a three-year history of knee pain and established diagnosis of osteoarthritis referred for consideration for total knee arthroplasty. He had no knee pain with passive range-of-motion. Plain films demonstrated bony erosions atypical for osteoarthritis. Joint aspiration white blood cell count was 30,548/mm³, but multiple cultures were positive for C. striatum. The infection was successfully treated with open irrigation and debridement, complete synovectomy, and six weeks of intravenous daptomycin.

Conclusion

To our knowledge, this is the first report of chronic C. striatum septic arthritis of a native joint and only the third case of C. striatum septic arthritis of the knee.C. striatum. The infection was successfully treated with open irrigation and debridement, complete synovectomy, and six weeks of intravenous daptomycin. C. striatum. The infection was successfully treated with open irrigation and debridement, complete synovectomy, and six weeks of intravenous daptomycin.

Antimicrobial Resistance and Molecular Epidemiology of Corynebacterium striatum Isolated in a Tertiary Hospital in Turkey

Although Corynebacterium striatum is part of the human flora, it has recently drawn attention both for its multidrug resistance and its role as an invasive infection/outbreak agent. This cross-sectional study aimed to determine the antimicrobial resistance and clonal relationships among C. striatum strains. In total, 81 C. striatum strains were identified using Phoenix-100^TM (BD, Sparks, MD, USA). The antimicrobial resistance of the strains was determined using the Kirby–Bauer disk diffusion method. Clonal relatedness among the strains was performed via arbitrarily primed polymerase chain reaction (AP-PCR). All 81 C. striatum strains were resistant to penicillin, cefotaxime, ciprofloxacin, and tetracycline, but susceptible to vancomycin and linezolid. The resistance rates to gentamicin, erythromycin, and clindamycin were 34.6%, 79%, and 87.7% respectively. AP-PCR results showed no predominant clone among the C. striatum strains. Corynebacterium striatum is reportedly the cause of an increasing number of invasive infections/outbreaks. Moreover, treatment options are limited. The study showed that vancomycin, linezolid, and gentamicin can be selected for the empirical treatment of C. striatum infections. Although no single-clone outbreak was observed in our hospital, small clonal circulations were observed within some units, indicating cross-contamination. Therefore, a comprehensive infection control program is warranted in future.

Whole-Genome Sequencing Reveals a Prolonged and Persistent Intrahospital Transmission of Corynebacterium striatum, an Emerging Multidrug-Resistant Pathogen

Corynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen that occurs primarily among immunocompromised and chronically ill patients. However, little is known about the genomic diversity of C. striatum, which contributes to its long-term persistence and transmission in hospitals. In this study, a total of 192 C. striatum isolates obtained from 14 September 2017 to 29 March 2018 in a hospital in Beijing, China, were analyzed by antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE). Whole-genome sequencing was conducted on 91 isolates. Nearly all isolates (96.3%, 183/190) were MDR. The highest resistance rate was observed for ciprofloxacin (99.0%, 190/192), followed by cefotaxime (90.6%, 174/192) and erythromycin (89.1%, 171/192). PFGE separated the 192 isolates into 79 pulsotypes, and differences in core genome single-nucleotide polymorphisms (SNPs) partitioned the 91 isolates sequenced into four clades. Isolates of the same pulsotype were identical or nearly identical at the genome level, with some exceptions. Two dominant subclones, clade 3a, and clade 4a, were responsible for the hospital-wide dissemination. Genomic analysis further revealed nine resistance genes mobilized by eight unique cassettes. PFGE and whole-genome sequencing revealed that the C. striatum isolates studied were the result mainly of predominant clones spreading in the hospital. C. striatum isolates in the hospital progressively acquired resistance to antimicrobial agents, demonstrating that isolates of C. striatum may adapt rapidly through the acquisition and accumulation of resistance genes and thus evolve into dominant and persistent clones. These insights will be useful for the prevention of C. striatum infection in hospitals.

Bloodstream and catheter-related infections due to different clones of multidrug-resistant and biofilm producer Corynebacterium striatum

BACKGROUND

Corynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen associated with immunocompromised and chronically ill patients, as well as nosocomial outbreaks. In this study, we characterized 23 MDR C. striatum isolated of bloodstream and catheter-related infections from a hospital of Rio de Janeiro.

METHODS

C. striatum isolates were identified by 16S rRNA and rpoB genes sequencing. The dissemination of these isolates was accomplished by pulsed-field gel electrophoresis (PFGE). All isolates were submitted to antimicrobial susceptibility testing by disk diffusion and by minimum inhibitory concentration using E-test strips methods. Antimicrobial resistance genes were detected by polymerase chain reaction. Quantitative tests were performed on four different abiotic surfaces and the ability to produce biofilm on the surface of polyurethane and silicone catheter was also demonstrated by scanning electron microscopy.

RESULTS

Eleven PFGE profiles were found. The PFGE profile I was the most frequently observed among isolates. Five different MDR profiles were found and all PFGE profile I isolates presented susceptibility only to tetracycline, vancomycin, linezolid and daptomycin. Only the multidrug-susceptible isolate did not show mutations in the quinolone-resistance determinant region (QRDR) of the gyrA gene and was negative in the search of genes encoding antibiotic resistance. The other 22 isolates were positive to resistance genes to aminoglycoside, macrolides/lincosamides and chloramphenicol and showed mutations in the QRDR of the gyrA gene. Scanning electron microscopy illustrated the ability of MDR blood isolate partaker of the epidemic clone (PFGE profile I) to produce mature biofilm on the surface of polyurethane and silicone catheter.

CONCLUSIONS

Genotyping analysis by PFGE revealed the permanence of the MDR PFGE profile I in the nosocomial environment. Other new PFGE profiles emerged as etiologic agents of invasive infections. However, the MDR PFGE profile I was also found predominant among patients with hematogenic infections. The high level of multidrug resistance associated with biofilm formation capacity observed in MDR C. striatum is a case of concern.

A novel isothermal amplification-based method for detection of Corynebacterium striatum

Corynebacterium striatum is an emerging multidrug-resistant pathogen causing increasing numbers of infections and nosocomial outbreaks worldwide. Thus, a simple, rapid and accurate method for C. striatum is urgently required for improving diagnosis efficiency. In this study, a C. striatum-multiple cross displacement amplification (MCDA) with visual detection reagent (VR) assay (C. striatum-MCDA-VR), which was a novel isothermal amplification-based method, was established to detect the species-specific ftr1 gene of C. striatum. Amplification was performed at a constant temperature (68 °C) for only 40 min, and the reaction results could be easily elucidated by observation of reaction mixture color when employing the VR. The limit of detection of this method was 10 fg of pure C. striatum DNA. No cross-reaction was observed with non-C. striatum strains. In testing of clinical sputum samples, the C. striatum-MCDA-VR assay showed excellent sensitivity and specificity when compared with sputum smear tests and PCR. The C. striatum-MCDA-VR assay is a simple, rapid and cost-effective approach for identifying C. striatum in microbiological laboratories, especially in resource-limited settings.

Molecular analysis of the endobronchial stent microbial biofilm reveals bacterial communities that associate with stent material and frequent fungal constituents

Endobronchial stents are increasingly used to treat airway complications in multiple conditions including lung transplantation but little is known about the biofilms that form on these devices. We applied deep sequencing to profile luminal biofilms of 46 endobronchial stents removed from 20 subjects primarily with lung transplantation-associated airway compromise. Microbial communities were analyzed by bacterial 16S rRNA and fungal ITS marker gene sequencing. Corynebacterium was the most common bacterial taxa across biofilm communities. Clustering analysis revealed three bacterial biofilm types: one low diversity and dominated by Corynebacterium; another was polymicrobial and characterized by Staphylococcus; and the third was polymicrobial and associated with Pseudomonas, Streptococcus, and Prevotella. Biofilm type was significantly correlated with stent material: covered metal with the Staphylococcus-type biofilm, silicone with the Corynebacterium-dominated biofilm, and uncovered metal with the polymicrobial biofilm. Subjects with sequential stents had frequent transitions between community types. Fungal analysis found Candida was most prevalent, Aspergillus was common and highly enriched in two of three stents associated with airway anastomotic dehiscence, and fungal taxa not typically considered pathogens were highly enriched in some stents. Thus, molecular analysis revealed a complex and dynamic endobronchial stent biofilm with three bacterial types that associate with stent material, a central role for Corynebacterium, and that both expected and unexpected fungi inhabit this unique niche. The current work provides a foundation for studies to investigate the relationship between stent biofilm composition and clinical outcomes, mechanisms of biofilm establishment, and strategies for improved stent technology and use in airway compromise.

Dirty Money on Holy Ground: Isolation of Potentially Pathogenic Bacteria and Fungi on Money Collected from Church Offerings

BACKGROUND

Fomites (including money) can transmit diseases to humans. How the nature of money influences contamination has not been adequately demonstrated. Moreover, such studies in church settings are non-existent. Thus, we studied how money collected from a church could serve as human disease transmission vehicles.

METHODS

Overall, 284 money samples (currency notes and coins) were collected during two Sundays in the months of Nov and Dec 2015 from a church congregation in Pretoria, Gauteng, South Africa. The presence of potentially pathogenic bacteria and fungi were investigated using culture (Colilert^® method) and molecular methods (Sanger sequencing). Scanning Electron Microscopy (SEM) was used to visualize the possible positions of the bacteria on various parts of a currency note.

RESULTS

Of the 192 samples (first sampling round), 76 (39.6%) were positive for E. coli. Smaller notes (R10) recorded the highest E. coli counts per note. Of the 92 notes analyzed for potentially pathogenic bacteria and fungi (second sampling round), 76 (82%) showed growth on at least one of the six culture media used. Sequencing revealed three bacterial (Bacillus, Staphylococcus and Corynebacterium) and two fungal (Clavispora and Rhodotorula) genera. SEM revealed that microorganisms could enter cracks of creased notes.

CONCLUSION

Unlike previous studies conducted where recent contamination could occur, the current study shows that microorganisms can survive on money; samples were collected from a church, where little or no exchange takes place. Moreover, using SEM demonstrates that aged and creased notes favor attachment of bacteria to money and could be of public health concern by transmitting disease within a given population.

Molecular epidemiology and clinical significance of Corynebacterium striatum isolated from clinical specimens

Purpose

This study investigated the clinical epidemiology, antimicrobial susceptibility, and molecular epidemiology of Corynebacterium striatum isolates.

Patients and methods

An observational study was conducted at a university hospital in the Republic of Korea from August to December 2016. All subjects were patients who tested positive for C. striatum clinically. Clinical data were analyzed to evaluate the microbiological and genotypic characteristics of C. striatum strains.

Results

Sixty-seven C. striatum isolates recovered from non-duplicated patients were characterized. Patients were classified into three groups according to the infection type: nosocomial infection (71.6%), health care-associated infection (8.7%), and community-acquired infection (18.8%). The most common clinical specimens were urine (35.8%) and skin abscesses (32.8%). Fifty-two (77.6%) isolates showed multidrug resistance, defined as resistance to ≥3 different antibiotic families. All strains were susceptible to vancomycin and linezolid. Resistance to other antibiotics varied: penicillin (n=65; 97.0%), ampicillin (n=63; 94.0%), cefotaxime (n=64; 95.5%), and levofloxacin (n=61; 91.0%). Phylogenetic analysis identified all 16 S rRNA gene sequences of the 67 isolates as those of C. striatum, where 98%–99% were homologous to C. striatum ATCC 6940. In multilocus sequence typing for internal transcribed spacer region, gyrA, and rpoB sequencing, the most predominant sequence types (STs) were ST2, ST3, ST6, and ST5.

Conclusion

C. striatum isolates may cause opportunistic infections associated with nosocomial infections through horizontal transmission. The presence of multidrug resistance and intra-hospital dissemination implicate C. striatum isolates as a potential target pathogen for infection control and antimicrobial stewardship programs.

Corynebacteria as a cause of pulmonary infection: a case series and literature review

Background

In most cases of community-acquired pneumonia (CAP), an etiologic agent is not determined; the most common report from the microbiological evaluation of sputum cites “normal respiratory flora.” Non-diphtheria Corynebacterium spp., a component of this flora, is commonly viewed as a contaminant, but it may be the cause of pneumonia and the frequency with which it causes CAP may be underestimated.

Case presentations

This report present 3 cases of CAP in which Corynebacterium spp. was clearly the predominant isolate; identification was confirmed by matrix-assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry. Two cases were caused by C. propinquum and one by C. striatum. Two patients had a tracheostomy and one was on hemodialysis. Patients who received an appropriate antibiotic responded well.

Conclusion

When identified as the predominant isolate in sputum from a patient with CAP, Corynebacterium spp. should be considered as a potential cause of the infection. In cases with patients who have compromised airway clearance or who are immunocompromised, microaspiration may be responsible. While some Corynebacterium spp. are suspectible to antibiotics usually prescribed for CAP, others are susceptible only to vancomycin or aminoglycosides. Vancomycin is thus the appropriate empiric antibiotic, pending speciation and susceptibility test results. The number of reported cases with result of antibiotic susceptibility testing, however, remains limited, and further investigation is needed. Non-diphtheria Corynebacterium spp. represent a noteworthy clinical cause of pneumonia. Identification by Gram stain and as a predominant organism on culture demands careful consideration for management.

Clinical Characteristics and Outcome of Lung Transplant Recipients with Respiratory Isolation of Corynebacterium spp

Although chronic respiratory disease and immunosuppression are risk factors for Corynebacterium species respiratory infection, data are scarce regarding this disease in lung transplantation. Our aim was to describe the clinical characteristics and outcomes of lung transplant recipients (LTR) with respiratory isolation of Corynebacterium spp. This was a retrospective observational study performed at a referral center in Barcelona, Spain (2014 to 2016). We included all LTR in whom Corynebacterium spp. were isolated in at least one good-quality lower respiratory tract specimen. Overall, 24 of 527 (4.6%) LTR at risk during the study period were included. The main epidemiological, clinical, and microbiological data were analyzed. The most frequently isolated species were C. striatum (11/24), C. pseudodiphtheriticum (3/24), and C. amycolatum (3/24). All 19 (76%) patients who underwent bronchoscopy showed abnormalities, mainly mucosal plaques at the bronchial suture and purulent secretions. Clinical cure was achieved in 8/12 (67%) patients who fulfilled the CDC definition of lower respiratory tract infection (LRTI). To assess the clinical relevance of Corynebacterium spp., only patients with monomicrobial isolation (n = 18) were evaluated. LRTI was diagnosed in 9, and a nonsignificant association was found with a significant number of Corynebacterium sp. CFU/ml (7/9 LRTI versus 2/9 non-LRTI, P = 0.057). Persistent infection was associated with metallic bronchial stent implantation (4/4 versus 2/14, P = 0.005). The isolation of Corynebacterium spp. in respiratory specimens of lung transplant recipients may herald a respiratory tract infection or bronchial suture damage. Bronchial stent implantation is a risk factor for the persistence of Corynebacterium species infection.

Genome sequence of a multidrug-resistant Corynebacterium striatum isolated from bloodstream infection from a nosocomial outbreak in Rio de Janeiro, Brazil

Multidrug-resistant (MDR) Corynebacterium striatum has been cited with increased frequency as pathogen of nosocomial infections. In this study, we report the draft genome of a C. striatum isolated from a patient with bloodstream infection in a hospital of Rio de Janeiro, Brazil. The isolate presented susceptibility only to tetracycline, vancomycin and linezolid. The detection of various antibiotic resistance genes is fully consistent with previously observed multidrug-resistant pattern in Corynebacterium spp. A large part of the pTP10 plasmid of MDR C. striatum M82B is present in the genome of our isolate. A SpaDEF cluster and seven arrays of CRISPR-Cas were found.

Factors affecting the clinical relevance of Corynebacterium striatum isolated from blood cultures

This study aimed to identify clinical or microbiological factors affecting the clinical relevance of Corynebacterium striatum isolated from blood cultures. A total of 64 isolates from 51 patients identified as C. striatum by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing were assessed. More than two blood cultures were positive in 25 (48.1%) patients. Diabetes, solid tumor, and a history of previous exposure to antibiotics were more common in patients with multiple positive blood cultures. Charlson comorbidity scores were also higher, and more isolates were recovered after 48 hours of hospital stay in patients with multiple positive blood cultures. Strains recovered from patients with multiple positive blood cultures produced significantly more biofilm. Based on multilocus sequence typing (MLST), sequence type (ST) 20 (31.3%) was the most dominant, followed by ST2 (20.3%) and ST23 (10.9%). There was no relationship between the number of positive blood culture sets and sequence typing. In multivariate analyses, Carlson comorbidity score (odds ratio [OR], 1.91; 95% confidence interval [CI], 1.09–3.36; P = 0.03) and biofilm formation were associated with multiple positive blood cultures (OR, 17.43; 95% CI, 3.71–81.91; P = 0.03). This study provides evidence that the biofilm phenotype could contribute to determining the clinical significance of C. striatum in patients with severe underlying conditions. The predominance of certain STs suggests the relatedness of C. striatum infection and the nosocomial environment.

Dust at Various Workplaces-Microbiological and Toxicological Threats

The aim of the present study was to evaluate the relation between the chemical (analysis of elements and pH) and microbiological composition (culture and metagenomics analysis) of the dust at various workplaces (cement plant, composting plant, poultry farm, and cultivated area) and the cytotoxicity effect on the human adenocarcinoma lung epithelial adherent cell line A-549 (MTT assay test). Analysis of the Particulate Matter (PM) fraction showed that the dust concentration in cultivated areas exceeded the OELs. For the remaining workplaces examined, the dust concentration was lower than OELs limits. The number of microorganisms in the dust samples was 3.8 × 10²–1.6 × 10⁸ CFU/g bacteria and 1.5 × 10²–6.5 × 10⁶ CFU/g fungi. The highest number of microorganisms was noted for dust from cultivated areas (total number of bacteria, actinomycetes, P. fluorescens) and composting plants (xerophilic fungi and staphylococci), while the least number of microorganisms was observed for dust from cement plants. Many types of potentially pathogenic microorganisms have been identified, including bacteria, such as Bacillus, Actinomyces, Corynebacterium, Prevotella, Clostridium, and Rickettsia, and fungi, such as Alternaria, Cladosporium, Penicillium, and Aspergillus. The most cytotoxic to the human lung cell line A-549 was dust from cultivated areas (IC₅₀ = 3.8 mg/mL after 72 h). The cytotoxicity of the tested dust samples depends on the PM concentration, the number of microorganisms, including potentially pathogenic genera, and the exposure time.

Clinical characteristics and predictive factors for mortality in coryneform bacteria bloodstream infection in hematological patients

BACKGROUND

We examined the clinical characteristics and predictive factors for mortality in coryneform bacteria bloodstream infection in hematological patients.

METHODS

We searched for hematological patients who had positive blood cultures for coryneform bacteria at our center between April 2007 and January 2016. Patients with definite bloodstream infections were included. We started species identification in April 2014.

RESULTS

Twenty of twenty-eight cases with a positive blood culture for coryneform bacteria were regarded as definite infections. Sixteen and two patients were allogeneic and autologous hematopoietic stem cell transplantation (HSCT) recipients, respectively. Corynebacterium striatum was identified in all nine of the cases tested and one patient was co-infected with Corynebacterium amycolatum. None of the patients died directly due to coryneform bacteria infection. The survival rates at 30, 60 and 180 days were 100%, 73.7% and 51.3%, respectively. Causes of mortality included progression of the underlying disease (n = 6), other infections (n = 4) and HSCT complications (n = 2). Mixed infection (hazard ratio (HR) 5.47, 95% confidence interval (CI) 1.30-23.0), renal impairment (HR 6.31, 95% CI 1.06-37.4) and absence of a central venous (CV) catheter at the onset (HR 6.39, 95% CI 1.04-39.45) were identified as predictive factors for mortality.

CONCLUSION

Most of the coryneform bacteria bloodstream infections occurred in HSCT recipients. Contamination seemed to be less common when coryneform bacteria were detected in blood in hematological patients. Although coryneform bacteria bloodstream infection seemed to mostly be manageable, the prognosis was not desirable, particularly in patients with mixed infection, renal impairment and absence of a CV catheter.

Clinical and bacteriological analyses of bacteremia due to Corynebacterium striatum

BACKGROUND

Corynebacterium striatum was recently recognized as a potential pathogen of various infectious diseases. However, the clinical entity of this microorganism has not been clearly identified. Therefore, we analyzed C. striatum isolates from blood culture and explored their clinical determinants.

METHODS

We reviewed the medical records of all patients from whom C. striatum isolates were recovered from blood culture for analysis of the patients' backgrounds and clinical course including response to antimicrobial therapy and prognosis.

RESULTS

During the 5-year study period (January 2010 to December 2014), 24 C. striatum strains were isolated from blood samples, and the frequency of C. striatum bacteremia increased. The majority of the strains were multidrug resistant. All of the tested strains were susceptible to only vancomycin. The age at onset of C. striatum bacteremia encompassed all adult age groups, and at least one underlying condition was documented in all patients. Thirteen of the 24 patients were cured using appropriate antibiotics (true infection group); however, 11 of the 24 patients were cured using inappropriate antibiotic therapy or no antibiotics (contamination group). Malignancy and neutropenia significantly increased the odds of true C. striatum bloodstream infection.

CONCLUSIONS

The Corynebacterium species is often considered a contaminant when isolated in culture. Instead, particularly when the strain is isolated from blood, the species should be considered clinically relevant and identified to the species level; in addition, antimicrobial susceptibility testing is recommended.

Characteristics of Multidrug-Resistant Corynebacterium spp. Isolated from Blood Cultures of Hospitalized Patients in Japan

Corynebacterium is a genus consisting of Gram-positive, rod-shaped bacteria, that is wildly distributed in nature. We report the epidemiological characterization of Corynebacterium spp. isolated from blood specimens at the Kurume University Hospital, between June 2008 and November 2011. Twenty-two strains that were likely Corynebacterium spp. were isolated from 22 hospitalized patients, of which 12 (54.5%) were identified as Corynebacterium striatum. Minimum inhibitory concentration tests were performed after biochemical and genotypic identifications. Biofilm production was detected using a 96-well microplate assay. The dissemination of C. striatum was investigated using pulsed-field gel electrophoresis (PFGE). All strains showed the tendency to be resistant to multiple drugs except vancomycin. Fourteen (82.4%) strains, including 9 C. striatum strains were capable of producing biofilms. Four distinct PFGE patterns were detected among C. striatum strains; 6 of which were identified as dominant pattern A (defined in this study) and had high biofilm production ability. During the 3-year monitoring period, these strains might have repeatedly infected the patients or could have readily colonized the hospital environments. C. striatum appeared to be a potential risk factor for bloodstream infections in hospitalized patients. More surveillance and enhanced control strategies are necessary to decrease Corynebacterium spp. infections in hospitals.

A case of fatal sepsis due to multidrug-resistant Corynebacterium striatum

BACKGROUND

Although non-diphtheria corynebacteria have traditionally been regarded as avirulent members of human bacterial flora, their pathogenic potential is increasingly recognized in our time. Reasons for this include the prolonged survival of severely ill and immunocompromised patients, the development of more invasive diagnostic and therapeutic procedures and the sub-optimal use of antibiotics that disrupts normal microbial balance and favors superinfections.

CASE REPORT

We present a rare case of sepsis due to multidrug-resistant Corynebacterium striatum in a 76-year-old host. The patient suffered from myelodysplastic syndrome and was on corticosteroid treatment due to atopic dermatitis. He had, also, a recent hospital admission and received a course of broad-spectrum antibiotics due to lower respiratory infection. The patient responded neither to empiric nor to targeted treatment and finally succumbed.

CONCLUSION

Diphtheroids are emerging pathogens capable of causing severe opportunistic infections. Their multidrugresistant nature renders treatment problematic and poses a threat to the currently established antimicrobial stewardship programs. Hippokratia 2016, 20(1): 67-69.

Draft Genome Sequence of Corynebacterium striatum 1961 BR-RJ/09, a Multidrug-Susceptible Strain Isolated from the Urine of a Hospitalized 37-Year-Old Female Patient

Corynebacterium striatum commonly colonizes the normal skin and nasopharyngeal tract of humans; however, this potentially pathogenic bacterium has been identified as the causative agent of several nosocomial infections. The current study describes the draft genome of strain 1961 BR-RJ/09, isolated from the urine of a hospitalized patient from Brazil.

AAC(3)-XI, a new aminoglycoside 3-N-acetyltransferase from Corynebacterium striatum

Corynebacterium striatum BM4687 was resistant to gentamicin and tobramycin but susceptible to kanamycin A and amikacin, a phenotype distinct among Gram-positive bacteria. Analysis of the entire genome of this strain did not detect any genes for known aminoglycoside resistance enzymes. Yet, annotation of the coding sequences identified 12 putative acetyltransferases or GCN5-related N-acetyltransferases. A total of 11 of these coding sequences were also present in the genomes of other Corynebacterium spp. The 12th coding sequence had 55 to 60% amino acid identity with acetyltransferases in Actinomycetales. The gene was cloned in Escherichia coli, where it conferred resistance to aminoglycosides by acetylation. The protein was purified to homogeneity, and its steady-state kinetic parameters were determined for dibekacin and kanamycin B. The product of the turnover of dibekacin was purified, and its structure was elucidated by high-field nuclear magnetic resonance (NMR), indicating transfer of the acetyl group to the amine at the C-3 position. Due to the unique profile of the reaction, it was designated aminoglycoside 3-N-acetyltransferase type XI.