Authors: Michael O Alberti, Janet A Hindler, Romney M Humphries...

Nutritionally variant streptococci (NVS) are fastidious Gram-positive cocci comprised of the species Abiotrophia defectiva, Granulicatella adiacens, and Granulicatella elegans. NVS are an important cause of bacteremia and infective endocarditis (IE) associated with significant morbidity and mortality. Antimicrobial susceptibility testing (AST) was performed for 14 antimicrobials using the broth microdilution MIC method described in the Clinical and Laboratory Standards Institute (CLSI) M45 guideline. A total of 132 clinical NVS blood isolates collected from 2008 to 2014 were tested. Species level identification of NVS isolates was achieved by 16S rRNA gene sequencing and/or matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Ninety isolates were identified as G. adiacens, 37 as A. defectiva, and 5 as G. elegans. All isolates were susceptible to vancomycin (MIC90 = 1 μg/ml), and none displayed high-level resistance to aminoglycosides. G. adiacens was considerably more susceptible to penicillin than A. defectiva (38.9% versus 10.8% of isolates susceptible) but was less susceptible to cephalosporins than was A. defectiva (43.3% versus 100% of isolates susceptible to ceftriaxone). Several isolates were resistant to levofloxacin (6%), erythromycin (51%), and clindamycin (10%). The MIC90 for daptomycin was ≥ 4 μg/ml for G. adiacens and A. defectiva. G. elegans isolates were 100% susceptible to all antimicrobials tested, with the exception of erythromycin, to which only 20% were susceptible. This study provides antimicrobial susceptibility data for a recent collection of NVS and demonstrates important NVS species-related differences with respect to susceptibility to penicillin, cephalosporins, carbapenems, and daptomycin. Species-level identification of NVS organisms when susceptibility testing is not readily available may aid in treatment decisions.

Topics: Abiotrophia; Anti-Bacterial Agents; Carnobacteriaceae; Gram-Positive Bacterial Infections; Humans; Los Angeles; Microbial Sensitivity Tests; Molecular Typing; RNA, Ribosomal, 16S; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; beta-Lactams

PubMed: 26666926
DOI: 10.1128/AAC.02645-15

Review

Authors: Andrea Perna, Luca Ricciardi, Carmelo Lucio Sturiale...

BACKGROUND

is a nutritional variant of streptococcus (NVS), which has been rarely reported as an etiologic agent in spondylodiscitis (SD).

MATERIAL AND METHODS

We report a case of a 51-year-old male with from chronic low-back pain associated with right sciatica and ipsilateral monoparesis. Spinal MRI showed radiological signs on L1-L2 and L5-S1 discs consistent with SD. We also performed a systematic review of the pertinent literature in order to retrieve all the key information regarding microbiological and clinical features.

RESULTS

Including our patients, seven cases with a mean age 56 ± 10.2 years were reported in English literature. Six patients were conservatively managed with antibiotic therapy (66%), whereas three with surgery in combination with antibiotics (33%). An endocarditis was associated in three cases, and a pacemaker infection in one. All patients received targeted antibiotic therapy resulting in a quick improvement of clinical symptoms with favorable outcome. Our case is the only with a skip spontaneous SD, which needed a surgical decompression due to the associated neurological symptoms.

CONCLUSIONS

This incidence of SD sustained by could be underestimated due to their particular microbiological conditions requested for their cultures. However, this infection should be suspected in cases of culture-negative SD, especially when associated with endocarditis.

PubMed: 32879584
DOI: 10.1016/j.jcot.2019.07.002

Authors: Geetarani Purohit, Baijayantimala Mishra, Satyajeet Sahoo...

, a nutritionally variant (NVS), is part of the normal commensal flora of human mouth, genital, and intestinal tracts and rarely causes disease. It has been mostly reported from bacteremia and endocarditis cases, but rarely can cause vertebral osteomyelitis, pancreatic abscess, otitis media, and endovascular, central nervous system, ocular, oral, bone and joint, and genitourinary infections. Due to requirement of fastidious culture conditions and non-specific colony morphology, serious diagnostic difficulties may arise in cases of NVS infections. Here, we are reporting a rare fatal infection of presented with empyema complicated to sepsis and necrotizing fasciitis. Clinicians should be aware of the pathogenic potential of (a normal commensal flora of human mouth, genital and intestinal tracts). Appropriate supplemented media and a reliable detection system should be used to identify these fastidious organisms. We present this rare case to bring awareness among clinicians regarding such a rare but potentially fatal infection.

PubMed: 36119420
DOI: 10.1055/s-0042-1744236

Review

Authors: Fanny Quénard, Piseth Seng, Jean-Christophe Lagier...

BACKGROUND

Bone and joint infection involving Granulicatella adiacens is rare, and mainly involved in cases of bacteremia and infectious endocarditis. Here we report three cases of prosthetic joint infection involving G. adiacens that were successfully treated with surgery and prolonged antimicrobial treatment. We also review the two cases of prosthetic joint infection involving G. adiacens that are reported in the literature.

CASE PRESENTATION

Not all five cases of prosthetic joint infection caused by G. adiacens were associated with bacteremia or infectious endocarditis. Dental care before the onset of infection was observed in two cases. The median time delay between arthroplasty implantation and the onset of infection was of 4 years (ranging between 2 and 10 years). One of our cases was identified with 16srRNA gene sequencing, one case with MALDI-TOF mass spectrometry, and one case with both techniques. Two literature cases were diagnosed by 16srRNA gene sequencing. All five cases were cured after surgery including a two-stage prosthesis exchange in three cases, a one-stage prosthesis exchange in one case, and debridement, antibiotics, irrigation, and retention of the prosthesis in one case, and prolonged antimicrobial treatment.

CONCLUSION

Prosthetic joint infection involving G. adiacens is probably often dismissed due to difficult culture or misdiagnosis, in particular in the cases of polymicrobial infection. Debridement, antibiotics, irrigation, and retention of the prosthesis associated with prolonged antimicrobial treatment (≥ 8 weeks) should be considered as a treatment strategy for prosthetic joint infection involving G. adiacens.

Topics: Adult; Aged; Carnobacteriaceae; Female; Hip Prosthesis; Humans; Knee Prosthesis; Male; Middle Aged; Prosthesis-Related Infections

PubMed: 28645272
DOI: 10.1186/s12891-017-1630-1

Authors: Ammara Mushtaq, Kerryl E Greenwood-Quaintance, Nicolynn C Cole...

MICs of 25 Abiotrophia defectiva and 109 Granulicatella adiacens isolates were determined by broth microdilution. Using CLSI breakpoints, the susceptibilities of A. defectiva and G. adiacens isolates were, respectively, 24% and 34% to penicillin, 92% and 22% to ceftriaxone, 48% and 3% to cefepime, 72% and 87% to meropenem, 92% and 10% to cefotaxime, 100% and 97% to levofloxacin, 92% and 80% to clindamycin, and 24% and 50% to erythromycin. All isolates were susceptible to vancomycin. In the penicillin-susceptible subgroup, all A. defectiva isolates were susceptible to ceftriaxone; however, 62% of G. adiacens isolates were ceftriaxone nonsusceptible.

Topics: Abiotrophia; Anti-Infective Agents; Carnobacteriaceae; Cefepime; Cefotaxime; Cephalosporins; Clindamycin; Erythromycin; Levofloxacin; Microbial Sensitivity Tests; Penicillins; Vancomycin

PubMed: 27216060
DOI: 10.1128/AAC.00485-16

Authors: Maribasappa Karched, Radhika G Bhardwaj, Ali Tiss...

Despite reports on the occurrence of in infective endocarditis, few mechanistic studies on its virulence characteristics or pathogenicity are available. Proteins secreted by this species may act as determinants of host-microbe interaction and play a role in virulence. Our aim in this study was to investigate and functionally characterize the secretome of . Proteins in the secretome preparation were digested by trypsin and applied to nanoLC-ESI-MS/MS. By using a combined mass spectrometry and bioinformatics approach, we identified 101 proteins. Bioinformatics tools predicting subcellular localization revealed that 18 of the secreted proteins possessed signal sequence. More than 20% of the secretome proteins were putative virulence proteins including serine protease, superoxide dismutase, aminopeptidase, molecular chaperone DnaK, and thioredoxin. Ribosomal proteins, molecular chaperones, and glycolytic enzymes, together known as "moonlighting proteins," comprised fifth of the secretome proteins. By Gene Ontology analysis, more than 60 proteins of the secretome were grouped in biological processes or molecular functions. KEGG pathway analysis disclosed that the secretome consisted of enzymes involved in biosynthesis of antibiotics. Cytokine profiling revealed that secreted proteins stimulated key cytokines, such as IL-1β, MCP-1, TNF-α, and RANTES from human PBMCs. In summary, the results from the current investigation of the secretome provide a basis for understanding possible pathogenic mechanisms of .

Topics: Bacterial Proteins; Carnobacteriaceae; Computational Biology; Endocarditis; Humans; Proteomics; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry; Virulence Factors

PubMed: 31069174
DOI: 10.3389/fcimb.2019.00104

Review

Authors: S Macin, A Ç İnkaya, Ö Tuncer...

Infections due to nutritionally variant streptococci are diagnosed rarely due to difficulties encountered during identification and isolation. Mortality rate in these infections is high therefore appropriate supplemented media and reliable detection systems should be implemented to isolate these fastidious organisms. Here, we describe two cases of Granulicatella adiacens infections. All microbiologic identifications were made with MALDI-TOF Vitek MS (BioMerieux, France), and the results confirmed by 16S ribotyping.

Topics: Adolescent; Carnobacteriaceae; Gram-Positive Bacterial Infections; Humans; Male; Middle Aged; RNA, Bacterial; RNA, Ribosomal, 16S; Ribotyping; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

PubMed: 27934842
DOI: 10.4103/0255-0857.195377

Authors: Binoy Mathews Nedumgottil

AIMS AND OBJECTIVE

Oral biofilms in denture wearers are populated with a large number of bacteria, a few of which have been associated with medical conditions such as sepsis and infective endocarditis (IE). The present study was designed to investigate the relative presence of pathogenic bacteria in biofilms of denture wearers specifically those that are associated with IE.

METHODS

Biofilm samples from 88 denture wearers were collected and processed to extract total genomic DNA. Eight of these samples were subjected to 16S rRNA gene sequencing analysis to first identify the general bacterial occurrence pattern. This was followed by species-specific quantitative polymerase chain reaction (qPCR) on entire batch of 88 samples to quantify the relative copy numbers of IE-associated pathogens.

RESULTS

16S rRNA gene analysis of eight biofilm samples identified bacteria from , , , and species. Interestingly, , , and from , all known to be associated with early-onset sepsis and IE was present in five of eight biofilm samples. The other three samples carried bacteria from genus with and , which are known to be commensals, as dominant species. Species-specific qPCR of , and on 88 biofilm DNA samples identified the presence of in 83%, in 79%, and in 76% of samples.

CONCLUSION

The findings from the present study demonstrate co-occurrence of , , and in a majority of denture wearers, which is clinically significant as elderly patients with compromised immune system are more prone to develop IE. To the best of our knowledge, the co-occurrence of , , and is being reported for the first time in biofilms of denture wearers.

PubMed: 29430138
DOI: 10.4103/jips.jips_183_17

Review

Authors: Kanne Padmaja, Vemu Lakshmi, Sreevdya Subramanian...

Infective endocarditis (IE) caused by nutritionally variant Streptococci (NVS) is associated with high bacteriologic and treatment failure and mortality rates compared to endocarditis caused by other Streptococci. With automated blood culture systems, the rates of NVS-associated IE accounts for 5%-6% cases. We report a case of IE caused by NVS in an elderly female patient with no risk factors. The patient was successfully treated with combination antimicrobial therapy.

Topics: Carnobacteriaceae; Endocarditis, Bacterial; Female; Gram-Positive Bacterial Infections; Humans; Middle Aged

PubMed: 24727523
DOI: 10.3855/jidc.3689

Review

Authors: K E Vandana, C Mukhopadhyay, N R Rau...

The fastidious Gram-positive cocci Granulicatella adiacens, previously known as nutritionally variant streptococci (NVS) are unusual but significant cause of endocarditis due to increased mortality and morbidity. Difficulties in reaching correct bacteriological identification, increased resistance to beta-lactam antibiotics and macrolides and complicated clinical course have contributed to problems in management of cases of infective endocarditis caused by this bacterium. We present the first Indian case of endocarditis with arterial embolus by G. adiacens in an elderly male with no preexisting cardiac abnormality.

Topics: Aged; Endocarditis, Bacterial; Femoral Artery; Humans; Lactobacillaceae; Male; Streptococcal Infections; Thromboembolism

PubMed: 21340307
DOI: No ID Found