Clinical relevance and antimicrobial susceptibility profile of the unknown human pathogen Corynebacterium aurimucosum

2021 ◽  
Vol 70 (3) ◽  
Author(s):  
Charles R. Lefèvre ◽  
Romain Pelletier ◽  
Alban Le Monnier ◽  
Stéphane Corvec ◽  
Emmanuelle Bille ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Clinical Relevance ◽  
Type Species ◽  
Clinical Isolates ◽  
Penicillin G ◽  
University Hospitals ◽  
Content Type ◽  
Link Type ◽  
Antimicrobial Susceptibility Profile ◽  
Tract Infections

Introduction. Even though Corynebacterium aurimucosum has been described in 2002, this species has long been underestimated due to the unreliability of conventional identification methods and only a few cases of infections have been reported. Hypothesis/Gap Statement. Little is known about clinical significance and antimicrobial susceptibility profile of this uncommon species. Aim. To evaluate the clinical relevance of C. aurimucosum and its antimicrobial susceptibility profile. Methodology. All C. aurimucosum isolates, collected from 2010 to 2019 in 10 French university hospitals, were retrospectively included. Demographic, clinical and microbiological data were collected for all cases. Antimicrobial susceptibility testing was performed according to the 2019 EUCAST guidelines. Results. Fifty-seven clinical isolates of C. aurimucosum were collected in 57 patients (median age, 65.8 years; male/female sex ratio, 1.1), mostly from urine (28 %), blood culture (28 %) and bone/synovial fluid (19 %) samples. Of them, 14 cases of infection were confirmed, mainly bone and joint infections (50 %) followed by urinary tract infections (UTIs) (21 %), bacteremia (14 %), skin and soft-tissue infections (14 %). C. aurimucosum was recovered in pure culture in 36 % of cases (UTIs and bacteremia) while mixed cultures were observed for other infections. By testing 52 clinical isolates in vitro, this species appeared to be fully susceptible to linezolid and vancomycin while most isolates (>80 %) were susceptible to amoxicillin (MIC90, 2 µg ml−1), gentamicin, tetracycline and rifampicin. Both cefotaxime and ciprofloxacin seemed to have a limited activity (ca. 50 % of susceptible strains). The MIC distribution for ciprofloxacin showed a bimodal profile with a population of highly-resistant strains with MICs >2 µg ml−1. Most isolates (>90 %) were categorized as resistant to penicillin G and clindamycin. Conclusion. C. aurimucosum should be considered as an actual opportunistic pathogen, and treatment with amoxicillin, vancomycin or linezolid should be preferred.

scholarly journals Nasopharyngeal carriage and antimicrobial susceptibility profile of Haemophilus influenzae among patients infected with HIV in Jakarta, Indonesia

2020 ◽  
Vol 2 (12) ◽  
Author(s):  
Dodi Safari ◽  
Agatha Nabilla Lestari ◽  
Miftahuddin Majid Khoeri ◽  
Wisnu Tafroji ◽  
Ernawati A. Giri-Rachman ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Hiv Infection ◽  
Antimicrobial Susceptibility ◽  
Type Species ◽  
Nasopharyngeal Carriage ◽  
Content Type ◽  
Link Type ◽  
Antimicrobial Susceptibility Profile

In this study, the prevalence of nasopharyngeal carriage and the antimicrobial susceptibility profile of Haemophilus influenzae were investigated in children and adults with HIV infection in Jakarta, Indonesia. Thirty-four H. influenzae isolates were identified in the children (n=16/90; 18%) and adults (n=18/200; 9%) infected with HIV. All isolates were nontypeable H. influenzae and were less susceptible to ampicillin (62%) and trimethoprim/sulfamethoxazole (41%). In this study, the H. influenzae strains carried by patients infected with HIV were dominated by non-capsulated types.

Antibiotic resistance and the presence of bla CfxA and bla CSP genes in β-lactamase-producing clinical Capnocytophaga isolates from a university hospital in Japan

2021 ◽  
Vol 70 (10) ◽  
Author(s):  
Takehisa Matsumoto ◽  
Miki Matsumoto-Matsubara ◽  
Kazuki Horiuchi ◽  
Eriko Arai ◽  
Tatsuya Negishi ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Type Species ◽  
Southern Hybridization ◽  
Test Method ◽  
Clinical Isolates ◽  
University Hospital ◽  
Clinical Samples ◽  
Content Type ◽  
Link Type ◽  
Hybridization Assays

Introduction . Capnocytophaga species are common inhabitants of the oral cavity and can be responsible for systemic diseases in immunocompromised patients with granulocytopenia. Furthermore, it has been reported that some clinical isolates of Capnocytophaga species produce extended-spectrum β-lactamases (ESBLs). Gap statement. Information is lacking about the types of β-lactamase genes possessed by Capnocytophaga spp. and the antimicrobial susceptibility of Capnocytophaga spp. possessing each β-lactamase gene. Aim. The aim of this study was to investigate the presence of β-lactamase genes in clinical strains of β-lactamase-producing Capnocytophaga species isolated from clinical samples acquired at Shinshu University Hospital and examine the antimicrobial susceptibility of those strains. Methodology. The β-lactamase-producing Capnocytophaga species (n=49) were obtained from clinical specimens. PCR assays were used to detect bla CfxA, bla CSP, bla TEM, bla CepA/CblA and transposon Tn4555 genes. Southern hybridization assays were used to detect bla CfxA and bla CSP. The minimum inhibitory concentration of some β-lactams was determined using the E-test method. Results. PCR analysis indicated that the bla CfxA gene was present in 15 (30.6 %) and the bla CSP gene in 35 (69.3 %) of the 49 Capnocytophaga strains investigated, . Both bla CfxA and bla CSP genes were detected in a Capnocytophaga gingivalis strain. The PCR results were confirmed by Southern hybridization assays. Transposon Tn4555 was only detected in Capnocytophaga spp. harbouring the bla CfxA gene. All the β-lactamase-producing Capnocytophaga isolates were susceptible to ceftazidime–clavulanic acid, cefoxitin and imipenem. In contrast, most of the isolates were resistant to amoxicillin. Conclusions. The clinical isolates of Capnocytophaga spp. showed a high prevalence of the bla CSP gene in Japan. The presence of the bla CSP gene was distributed in Capnocytophaga sputigena as well as other Capnocytophaga spp. These results seem to suggest the dissemination of bla CfxA and bla CSP β-lactamase genes among Capnocytophaga species.

Difference in drug susceptibility distribution and clinical characteristics between Mycobacterium avium and Mycobacterium intracellulare lung diseases in Shanghai, China

2021 ◽  
Vol 70 (5) ◽  
Author(s):  
Weiping Wang ◽  
Jinghui Yang ◽  
Xiaocui Wu ◽  
Baoshan Wan ◽  
Hongxiu Wang ◽  
...  
Keyword(s):  
Mycobacterium Avium ◽  
Antimicrobial Susceptibility ◽  
Type Species ◽  
Clinical Characteristics ◽  
Radiographic Findings ◽  
Content Type ◽  
Mycobacterium Intracellulare ◽  
Link Type ◽  
Broth Microdilution Method ◽  
Significant Difference

Introduction. Mycobacterium avium complex (MAC) has been reported as the most common aetiology of lung disease involving nontuberculous mycobacteria. Hypothesis. Antimicrobial susceptibility and clinical characteristics may differ between Mycobacterium avium and Mycobacterium intracellulare . Aim. We aimed to evaluate the differences in antimicrobial susceptibility profiles between two major MAC species ( Mycobacterium avium and Mycobacterium intracellulare ) from patients with pulmonary infections and to provide epidemiologic data with minimum inhibitory concentration (MIC) distributions. Methodology. Between January 2019 and May 2020, 45 M. avium and 242 M . intracellulare isolates were obtained from Shanghai Pulmonary Hospital. The demographic and clinical characteristics of patients were obtained from their medical records. The MICs of 13 antimicrobials were determined for the MAC isolates using commercial Sensititre SLOWMYCO MIC plates and the broth microdilution method, as recommended by the Clinical and Laboratory Standards Institute (CLSI; Standards M24-A2). MIC50 and MIC90 values were derived from the MIC distributions. Results. M. intracellulare had higher resistance rates than M. avium for most tested antimicrobials except clarithromycin, ethambutol, and ciprofloxacin. Clarithromycin was the most effective antimicrobial against both the M. avium (88.89 %) and M. intracellulare (91.32 %) isolates, with no significant difference between the species (P=0.601). The MIC90 of clarithromycin was higher for M. avium (32 µg ml−1) than M. intracellulare (8 µg ml−1). The MIC50 of rifabutin was more than four times higher for M. intracellulare (1 µg ml−1) than M. avium (≤0.25 µg ml−1). The percentages of patients aged >60 years and patients with sputum, cough, and cavitary lesions were significantly higher than among patients with M. intracellulare infection than M. avium infections. Conclusions. The pulmonary disease caused by distinct MAC species had different antimicrobial susceptibility, symptoms, and radiographic findings.

scholarly journals Antibacterial activity of high-dose nitric oxide against pulmonary Mycobacterium abscessus disease

2020 ◽  
Vol 2 (9) ◽  
Author(s):  
Kristijan Bogdanovski ◽  
Trisha Chau ◽  
Chevalia J. Robinson ◽  
Sandra D. MacDonald ◽  
Ann M. Peterson ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Antibacterial Activity ◽  
Type Species ◽  
Mycobacterium Abscessus ◽  
Clinical Isolates ◽  
Content Type ◽  
Link Type ◽  
Susceptibility Tests ◽  
Inhaled No

Introduction. Mycobacterium abscessus is an emerging pulmonary pathogen with limited treatment options. Nitric oxide (NO) demonstrates antibacterial activity against various bacterial species, including mycobacteria. In this study, we evaluated the effect of adjunctive inhaled NO therapy, using a novel NO generator, in a CF patient with pulmonary M. abscessus disease, and examined heterogeneity of response to NO in vitro. Methods. In the compassionate-use treatment, a 24-year-old CF patient with pulmonary M. abscessus was treated with two courses of adjunctive intermittent NO, first at 160 p.p.m. for 21 days and subsequently by escalating the dose up to 240 p.p.m. for 8 days. Methemoglobin, pulmonary function, 6 min walk distance (6MWD), qualify of life and sputum microbiology were assessed. In vitro susceptibility tests were performed against patient’s isolate and comparison clinical isolates and quantified by Hill’s slopes calculated from time–kill curves. Results. M. abscessus lung infection eradication was not achieved, but improvements in selected qualify of life domains, lung function and 6MWD were observed during the study. Inhaled NO was well tolerated at 160 p.p.m. Dosing at 240 p.p.m. was stopped due to adverse symptoms, although methemoglobin levels remained within safety thresholds. In vitro susceptibility tests showed a dose-dependent NO effect on M. abscessus susceptibility and significant heterogeneity in response between M. abscessus clinical isolates. The patient’s isolate was found to be the least susceptible strain in vitro. Conclusion. These results demonstrate heterogeneity in M. abscessus susceptibility to NO and suggest that longer treatment regimens could be required to see the reduction or eradication of more resistant pulmonary strains.

scholarly journals Brachybacterium ginsengisoli sp. nov., isolated from soil of a ginseng field

2014 ◽  
Vol 64 (Pt_9) ◽  
pp. 3063-3068 ◽  
Author(s):  
Van-An Hoang ◽  
Yeon-Ju Kim ◽  
Ngoc-Lan Nguyen ◽  
Deok-Chun Yang
Keyword(s):  
Type Species ◽  
Diaminopimelic Acid ◽  
Penicillin G ◽  
Rrna Gene ◽  
Aerobic Bacterium ◽  
Content Type ◽  
Link Type ◽  
Gram Staining ◽  
Diamino Acid ◽  
The Republic

A novel Gram-staining-positive, aerobic bacterium, designed DCY80T, was isolated from soil of a ginseng field in the Republic of Korea. 16S rRNA gene sequence analysis revealed that strain DCY80T belonged to the genus Brachybacterium (95.8–98.2 % similarity) and was most closely related to Brachybacterium faecium DSM 4810T (98.2 %). Colonies were circular, entire, low-convex, opaque and 0.5–1.0 mm in diameter after growth for 2 days on TSA at 30 °C. Growth occurred at 4–34 °C (optimum, 25 °C), at pH 5.0–10.0 (optimum, pH 6.5–7.0) and in the presence of 0–7.0 % NaCl. Strain DCY80T produced siderophores and was sensitive to penicillin G, erythromycin, cefazolin, oleandomycin, ceftazidime, vancomycin, tetracycline, novobiocin, carbamicillin, rifampicin and neomycin. The DNA G+C content was 71.0 mol%. Levels of DNA–DNA relatedness between strain DCY80T and B. faecium DSM 4810T, B. paraconglomeratum KCTC 9916T, B. saurashtrense DSM 23186T and B. conglomeratum KCTC 9915T were 46.9±0.5, 28.9±0.6, 20.4±0.9 and 17.3±0.4 %, respectively. The cell-wall peptidoglycan of strain DCY80T contained meso-diaminopimelic acid as the diagnostic diamino acid. The menaquinones were MK-7 (85.8 %) and MK-8 (14.2 %). The major cellular fatty acids were anteiso-C15 : 0 (69.1 %) and anteiso-C17 : 0 (12.2 %). Phosphatidylglycerol, diphosphatidylglycerol, an unidentified glycolipid, two unidentified phospholipids and five unidentified polar lipids were found. On the basis of our phenotypic and genotypic analyses, strain DCY80T represents a novel species of the genus Brachybacterium , for which the name Brachybacterium ginsengisoli sp. nov. is proposed (type strain DCY80T = KCTC 29226T = JCM 19356T).

scholarly journals Highly multidrug-resistant Morganella morganii clinical isolates from Nepal co-producing NDM-type metallo-β-lactamases and the 16S rRNA methylase ArmA

2020 ◽  
Vol 69 (4) ◽  
pp. 572-575
Author(s):  
Shovita Shrestha ◽  
Tatsuya Tada ◽  
Jatan B. Sherchan ◽  
Hiroki Uchida ◽  
Tomomi Hishinuma ◽  
...  
Keyword(s):  
16S Rrna ◽  
Control Systems ◽  
Type Species ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Morganella Morganii ◽  
Content Type ◽  
Link Type ◽  
16S Rrna Methylase ◽  
Multiple Antibiotics

Morganella morganii can harbour extended-spectrum β-lactamases and carbapenemases, resulting in increased resistance to multiple antibiotics and a high mortality rate. This study describes the emergence of highly multidrug-resistant clinical isolates of M. morganii from Nepal co-producing NDM-type metallo-β-lactamases, including NDM-1 and NDM-5, and the 16S rRNA methylase ArmA. This is the first report of M. morganii clinical isolates from Nepal co-producing NDM-1/-5 and ArmA. It is important to establish infection control systems and effective treatments against multidrug-resistant M. morganii .

scholarly journals A novel hemA mutation is responsible for a small-colony-variant phenotype in Escherichia coli

Microbiology ◽  
2020 ◽  
Author(s):  
Alasdair T. M. Hubbard ◽  
Issra Bulgasim ◽  
Adam P. Roberts
Keyword(s):  
Escherichia Coli ◽  
Mammalian Cells ◽  
Type Species ◽  
Fitness Cost ◽  
Growth Media ◽  
Content Type ◽  
Small Colony Variant ◽  
Link Type ◽  
Small Colony ◽  
Tract Infections

We identified a small colony variant (SCV) of an amoxicillin/clavulanic acid-resistant derivative of a clinical isolate of Escherichia coli from Malawi, which was selected for in vitro in a subinhibitory concentration of gentamicin. The SCV was auxotrophic for hemin and had impaired biofilm formation compared to the ancestral isolates. A single novel nucleotide polymorphism (SNP) in hemA, which encodes a glutamyl-tRNA reductase that catalyses the initial step of porphyrin biosynthesis leading to the production of haem, was responsible for the SCV phenotype. We showed the SNP in hemA resulted in a significant fitness cost to the isolate, which persisted even in the presence of hemin. However, the phenotype quickly reverted during sequential sub-culturing in liquid growth media. As hemA is not found in mammalian cells, and disruption of the gene results in a significant fitness cost, it represents a potential target for novel drug development specifically for the treatment of catheter-associated urinary tract infections caused by E. coli .

Rifampin-resistance-associated mutations in the rifampin-resistance-determining region of the rpoB gene of Mycobacterium tuberculosis clinical isolates in Shanghai, PR China

2021 ◽  
Author(s):  
Yinjuan Guo ◽  
Xingwei Cao ◽  
Jinghui Yang ◽  
Xiaocui Wu ◽  
Yin Liu ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Type Species ◽  
Mutation Frequency ◽  
Rpob Gene ◽  
Clinical Isolates ◽  
Content Type ◽  
Link Type ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Rifampin Resistance

Introduction. Resistance to rifampin (RIF) in Mycobacterium tuberculosis infection is associated with mutations in the rpoB gene coding for the β-subunit of RNA polymerase. The contribution of various rpoB mutations to the development and level of RIF resistance remains elusive. Hypothesis/Gap Statement. Various rpoB mutations may be associated with differential levels of RIF resistance. Aim. This study aimed to investigate the relationship between specific rpoB mutations and the MICs of RIF and rifabutin (RFB) against M. tuberculosis . Methodology. Of the 195 clinical isolates, 105 and 90 isolates were randomly selected from isolates resistant to RIF and sensitive to RIF, respectively. The MICs of 12 agents for M. tuberculosis isolates were determined using commercial Sensititre M. tuberculosis MIC plates and the broth microdilution method. Strains were screened for rpoB mutations by DNA extraction, rpoB gene amplification and DNA sequence analysis. Results. One hundred isolates (95.24 %) were found to have mutations in the RIF-resistance-determining region (RRDR) of the rpoB gene. Three rpoB mutations were identified in 90 RIF-susceptible isolates. Out of 105 isolates, 86 (81.90 %) were cross-resistant to both RIF and RFB. The most frequent mutation occurred at codons 450 and 445. We also found a novel nine-nucleotide (ATCATGCAT) deletion (between positions 1543 and 1551) in the rpoB gene in two strains (1.90 %) with resistance to RIF, but susceptibility to RFB. In addition, the mutation frequency at codon 450 was significantly higher in RIF-resistant/RFB-resistant (RIFR/RFBR) strains than in RIFR/RFBS strains (75.58 % versus 21.05 %, P<0.01), whereas the mutation frequency at codon 435 was significantly lower in RIFR/RFBR strains than in RIFR/RFBS strains (1.16 % versus 26.32 %, P<0.01). Conclusion. Our data support previous findings, which reported that various rpoB mutations are associated with differential levels of RIF resistance. The specific mutations in the rpoB gene in RIFR/RFBR isolates differed from those in the RIFR/RFBS isolates. A novel deletion mutation in the RRDR might be associated with resistance to RIF, but not to RFB. Further clinical studies are required to investigate the efficacy of RFB in the treatment of infections caused by M. tuberculosis strains harbouring these mutations.

scholarly journals Pathogenomic analyses of Mycobacterium microti, an ESX-1-deleted member of the Mycobacterium tuberculosis complex causing disease in various hosts

2021 ◽  
Vol 7 (2) ◽  
Author(s):  
Mickael Orgeur ◽  
Wafa Frigui ◽  
Alexandre Pawlik ◽  
Simon Clark ◽  
Ann Williams ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Guinea Pig ◽  
Type Species ◽  
Clinical Isolates ◽  
Recent Common Ancestor ◽  
Genome Sequences ◽  
Content Type ◽  
Link Type ◽  
Vaccine Potential ◽  
Mycobacterium Microti

Mycobacterium microti is an animal-adapted member of the Mycobacterium tuberculosis complex (MTBC), which was originally isolated from voles, but has more recently also been isolated from other selected mammalian hosts, including occasionally from humans. Here, we have generated and analysed the complete genome sequences of five representative vole and clinical M. microti isolates using PacBio- and Illumina-based technologies, and have tested their virulence and vaccine potential in SCID (severe combined immune deficient) mouse and/or guinea pig infection models. We show that the clinical isolates studied here cluster separately in the phylogenetic tree from vole isolates and other clades from publicly available M. microti genome sequences. These data also confirm that the vole and clinical M. microti isolates were all lacking the specific RD1mic region, which in other tubercle bacilli encodes the ESX-1 type VII secretion system. Biochemical analysis further revealed marked phenotypic differences between isolates in type VII-mediated secretion of selected PE and PPE proteins, which in part were attributed to specific genetic polymorphisms. Infection experiments in the highly susceptible SCID mouse model showed that the clinical isolates were significantly more virulent than the tested vole isolates, but still much less virulent than the M. tuberculosis H37Rv control strain. The strong attenuation of the ATCC 35872 vole isolate in immunocompromised mice, even compared to the attenuated BCG (bacillus Calmette–Guérin) vaccine, and its historic use in human vaccine trials encouraged us to test this strain’s vaccine potential in a guinea pig model, where it demonstrated similar protective efficacy as a BCG control, making it a strong candidate for vaccination of immunocompromised individuals in whom BCG vaccination is contra-indicated. Overall, we provide new insights into the genomic and phenotypic variabilities and particularities of members of an understudied clade of the MTBC, which all share a recent common ancestor that is characterized by the deletion of the RD1mic region.

scholarly journals Genomic insights into the diversity, virulence and resistance of Klebsiella pneumoniae extensively drug resistant clinical isolates

2021 ◽  
Vol 7 (8) ◽  
Author(s):  
Amy H. Y Lee ◽  
William F. Porto ◽  
Célio de Faria Jr ◽  
Simoni C. Dias ◽  
Sérgio A. Alencar ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Genome Size ◽  
Type Species ◽  
Target Function ◽  
Clinical Isolates ◽  
Drug Resistant ◽  
Content Type ◽  
Link Type ◽  
Extensively Drug Resistant ◽  
Class B

Klebsiella pneumoniae has been implicated in wide-ranging nosocomial outbreaks, causing severe infections without effective treatments due to antibiotic resistance. Here, we performed genome sequencing of 70 extensively drug resistant clinical isolates, collected from Brasília’s hospitals (Brazil) between 2010 and 2014. The majority of strains (60 out of 70) belonged to a single clonal complex (CC), CC258, which has become distributed worldwide in the last two decades. Of these CC258 strains, 44 strains were classified as sequence type 11 (ST11) and fell into two distinct clades, but no ST258 strains were found. These 70 strains had a pan-genome size of 10 366 genes, with a core-genome size of ~4476 genes found in 95 % of isolates. Analysis of sequences revealed diverse mechanisms of resistance, including production of multidrug efflux pumps, enzymes with the same target function but with reduced or no affinity to the drug, and proteins that protected the drug target or inactivated the drug. β-Lactamase production provided the most notable mechanism associated with K. pneumoniae . Each strain presented two or three different β-lactamase enzymes, including class A (SHV, CTX-M and KPC), class B and class C AmpC enzymes, although no class D β-lactamase was identified. Strains carrying the NDM enzyme involved three different ST types, suggesting that there was no common genetic origin.

Sign in / Sign up

Export Citation Format

Share Document