Clinical and microbiological features of bacteraemia with Gram-positive anaerobic cocci: a population-based retrospective study

Description of Anaerococcus kampingiae sp. nov., Anaerococcus groningensis sp. nov., Anaerococcus martiniensis sp. nov., and Anaerococcus cruorum sp. nov., isolated from human clinical specimens

OBJECTIVES

To improve the identification of anaerobic bacteria, the identity of clinical isolates which could not be identified using MALDI-TOF MS was assessed using whole genome sequencing (WGS) and in-house made main spectral profiles (MSPs) were created. Four novel Anaerococcus species, each represented by at least two isolates, were encountered.

METHODS

The novelty of the isolates was confirmed by comparing the 16S rRNA gene sequences and the WGS with their closest relatives. Phylogenetic and phylogenomic relationships were determined using MEGA X and DSMZ TYGS. Biochemical features were determined and the clustering of the created MSPs was calculated. Possible clinical relevance was assessed.

RESULTS

The novelty of the four different species was confirmed by the ANI value, and phylogenetic/phylogenomic clustering. Three of these species shared the same biochemical features, while one showed a different pattern. Only this latter species can be differentiated from other Anaerococcus spp. Remarkebly, six of the ten isolates were obtained from a positive blood culture, of which in five cases the bacterium was the only species encountered.

CONCLUSIONS

We propose to name these novel species: Anaerococcus kampingiae (ENR0874T = DSM 117234T, CCUG 77487T (accession numbers PP192775/JBGMEF000000000)), Anaerococcus groningensis (ENR1011T = DSM 117232T, CCUG 77488T (accession numbers PP192777/JBGMEG000000000)), Anaerococcus martiniensis (ENR0831T = DSM 117233T, CCUG 77486T (accession numbers PP192776/JBGMEI000000000)), and Anaerococcus cruorum (ENR1039T = DSM 117235T, CCUG 77489T (accession numbers PP192778/JBGMEH000000000)).

Anaerobic bacteria dominate the cholesteatoma tissue of chronic suppurative otitis media patients

The aim of this study was to investigate both the microbial composition and absolute abundance of clinically relevant bacteria in tissue specimens from patients with chronic suppurative otitis media with cholesteatoma (CSOM with cholesteatoma). Mastoid mucosa and cholesteatoma tissue from eleven subjects with CSOM with cholesteatoma, and mastoid mucosa from ten controls were examined using standard hospital culture swabs, Gram staining, bacterial 16S rRNA gene sequencing, Droplet Digital PCR (ddPCR), and multiplex PCR. Positive results from culture swabs were reported in half the CSOM with cholesteatoma samples and 1 control sample. In contrast, ddPCR detected bacterial genes copies in all 11 mucosa and cholesteatoma of CSOM subjects and 3 control samples. The average bacterial gene copies in tissue samples with CSOM with cholesteaotoma (1.6 ± 0.7 log10) was significantly higher compared to healthy controls (0.3 ± 1.6). These results were corroborated with Gram-staining that identified the large presence of Gram-positive cocci cells in the cholesteatoma tissue of CSOM subjects which were not seen in the mucosa of controls. The most abundant genus detected by sequencing in the mucosa and cholesteatoma of CSOM samples was Anaerococcus (93.5 % of all reads), and genus Meiothermus (0.9 %) in the control sample. The 3 samples with the highest sequencing reads (>300) were further analysed using multiplex PCR to identify the dominant Anaerococcus species. Anaerococcus hydrogenalis was the dominant species identified in these samples. In contract, commonly named ear pathogens, genera Staphylococcus and Pseudomonas, were detected in low numbers (<0.001 % of all sequencing reads) and low prevalence (2/16 samples) in the tissue samples of this study. The results show that culture severely underestimated the bacterial diversity in CSOM samples and investigating tissue rather than standard culture swabs might be advantageous to understanding the disease process. The high abundance of bacteria and the large presence of Gram-positive cells detected in the cholesteatoma tissue of CSOM compared to mucosa of CSOM or controls could be members from the genus Anaerococcus. Anaerococcus may well be a pathogen in CSOM with cholesteatoma, but their role in this condition requires further investigation.

Target next-generation sequencing for the accurate diagnosis of Parvimonas micra lung abscess: a case series and literature review

Background

Parvimonas micra (P. micra) has been identified as a pathogen capable of causing lung abscesses; however, its identification poses challenges due to the specialized culture conditions for anaerobic bacterial isolation. Only a few cases of lung abscesses caused by P. micra infection have been reported. Therefore, we describe the clinical characteristics of lung abscesses due to P. micra based on our case series.

Methods

A retrospective analysis was conducted on eight patients who were diagnosed with lung abscesses attributed to P. micra. Detection of P. micra was accomplished through target next-generation sequencing (tNGS). A systematic search of the PubMed database using keywords "lung abscess" and "Parvimonas micra/Peptostreptococcus micros" was performed to review published literature pertaining to similar cases.

Results

Among the eight patients reviewed, all exhibited poor oral hygiene, with four presenting with comorbid diabetes. Chest computed tomography (CT) showed high-density mass shadows with necrosis and small cavities in the middle. Bronchoscopic examination revealed purulent sputum and bronchial mucosal inflammation. Thick secretions obstructed the airway, leading to the poor drainage of pus, and the formation of local abscesses leading to irresponsive to antibiotic therapy, which finally protracted recovery time. P. micra was successfully identified in bronchoalveolar lavage fluid (BALF) samples from all eight patients using tNGS; in contrast, sputum and BALF bacterial cultures yielded negative results, with P. micra cultured from only one empyema sample. Following appropriate antibiotic therapy, seven patients recovered. In previously documented cases, favorable outcomes were observed in 77.8% of individuals treated with antibiotics and 22.2% were cured after surgical interventions for P. micra lung abscesses.

Conclusions

This study enriches our understanding of the clinical characteristics associated with lung abscesses attributed to P. micra. Importantly, tNGS has emerged as a rapid and effective diagnostic test in scenarios where traditional sputum cultures are negative. Encouragingly, patients with lung abscesses caused by P. micra infection exhibit a favorable prognosis with effective airway clearance and judicious anti-infective management.

Fannyhessea vaginae causing bacteraemia and vertebral osteomyelitis: first report of invasive disease in a male

Introduction.Fannyhessea vaginae (formerly Atopobium vaginae) is an anaerobic organism commonly associated with female genital flora, with rare cases of invasive disease reported in females. Case report. We discuss the case of an 81-year-old male who presented with an acute history of back pain and signs of urinary tract infection in the context of intermittent self-urinary catheterisation. Multiple blood cultures grew Fannyhessea vaginae with a later finding of lumbar vertebral osteomyelitis as the cause of back pain. Treatment was commenced with ampicillin, later switched to ceftriaxone, with improvement of acute signs of infection. Conclusion. Gram-positive anaerobic organisms including Fannyhessea vaginae are possibly under-recognised causes of urinary tract particularly in older males. These bacteria may prove challenging to grow in standard protocols for urine culture; anaerobic or extended incubation could be considered particularly in complicated cases of urinary tract infection without an identifiable pathogen.

Hemoptysis caused by Parvimonas micra: case report and literature review

Background

Parvimonas micra (P. micra), a Gram-positive anaerobic bacterium, exhibits colonization tendencies on oral mucosal and skin surfaces, potentially evolving into a pathogenic entity associated with diverse diseases. The diagnostic trajectory for P. micra-related diseases encounters delays, often with severe consequences, including fatality, attributed to the absence of symptom specificity and challenges in culture. The absence of a consensus on the diagnostic and therapeutic approaches to P. micra exacerbates the complexity of addressing associated conditions. This study aims to elucidate and scrutinize the clinical manifestations linked to P. micra, drawing insights from an extensive literature review of pertinent case reports.

Case presentation

A 53-year-old male sought medical attention at our institution presenting with recurrent hemoptysis. Empirical treatment was initiated while awaiting pathogen culture results; however, the patient's symptoms persisted. Subsequent metagenomic next-generation sequencing (mNGS) analysis revealed a pulmonary infection attributable to P. micra. Resolution of symptoms occurred following treatment with piperacillin sulbactam sodium and moxifloxacin hydrochloride. A comprehensive literature review, utilizing the PubMed database, was conducted to assess case reports over the last decade where P. micra was identified as the causative agent.

Conclusion

The literature analysis underscores the predilection of P. micra for immunocompromised populations afflicted by cardiovascular diseases, diabetes, orthopedic conditions, and tumors. Risk factors, including oral and periodontal hygiene, smoking, and alcohol consumption, were found to be associated with P. micra infections. Clinical manifestations encompassed fever, cough, sputum production, and back pain, potentially leading to severe outcomes such as Spondylodiscitis, septic arthritis, lung abscess, bacteremia, sepsis, and mortality. While conventional bacterial culture remains the primary diagnostic tool, emerging technologies like mNGS offer alternative considerations. In terms of treatment modalities, β-lactam antibiotics and nitroimidazoles predominated, exhibiting recovery rates of 56.10% (46/82) and 23.17% (19/82), respectively. This case report and literature review collectively aim to enhance awareness among clinicians and laboratory medicine professionals regarding the intricacies of P. micra-associated infections.

Characteristics of the gut microbiota of patients with symptomatic carotid atherosclerotic plaques positive for bacterial genetic material

Background

The gut microbiota (GM) is believed to be closely associated with symptomatic carotid atherosclerosis (SCAS), yet more evidence is needed to substantiate the significant role of GM in SCAS. This study, based on the detection of bacterial DNA in carotid plaques, explores the characteristics of GM in SCAS patients with plaque bacterial genetic material positivity, aiming to provide a reference for subsequent research.

Methods

We enrolled 27 healthy individuals (NHF group) and 23 SCAS patients (PFBS group). We utilized 16S rDNA V3-V4 region gene sequencing to analyze the microbiota in fecal samples from both groups, as well as in plaque samples from the carotid bifurcation extending to the origin of the internal carotid artery in all patients.

Results

Our results indicate significant differences in the gut microbiota (GM) between SCAS patients and healthy individuals. The detection rate of bacterial DNA in plaque samples was approximately 26%. Compared to patients with negative plaques (PRSOPWNP group), those with positive plaques (PRSOPWPP group) exhibited significant alterations in their GM, particularly an upregulation of 11 bacterial genera (such as Klebsiella and Streptococcus) in the gut, which were also present in the plaques. In terms of microbial gene function prediction, pathways such as Fluorobenzoate degradation were significantly upregulated in the GM of patients with positive plaques.

Conclusion

In summary, our study is the first to identify significant alterations in the gut microbiota of patients with positive plaques, providing crucial microbial evidence for further exploration of the pathogenesis of SCAS.

Empyema and bacteremia caused by Parvimonas micra: A case report

Parvimonas micra is a gram-positive anaerobic coccus (GPAC) that colonizes the oral cavity and gastrointestinal tract. Recent advances in bacterial identification have confirmed the clinical importance of Parvimonas micra. Here, we report a case of empyema with bacteremia caused by Parvimonas micra. We successfully treated the patient with the appropriate antibiotics and drainage. Parvimonas micra can cause respiratory infections, including empyema, which can progress to bacteremia if treatment is delayed. In Parvimonas micra infections, not only the oral cavity but also the entire body must be investigated to clarify the entry mechanism.

Parvimonas micra a new potential pathogen in hospitalized patients: a case series from 2015-2022

Parvimonas micra isolations are usually part of polymicrobial infections and the pathogenic role of this microrganism is still debated. We describe here a large series of hospitalized patients diagnosed with Parvimonas micra infections and discuss the clinical and therapeutic management and the outcome of these infections.

Fusobacterium ulcerans. From tropical ulcers to gut commensal and bacterial translocation?

The genusFusobacterium contains currently 13 species presenting as non-spore-forming, obligate anaerobic, gram-negative fusiform rods. Fusobacterium ulcerans was discovered in 1988 causing tropical ulcers. We present the case of a patient with diverticulitis complicated with bacteremia. Both aerobic bottles were positive at 20 and 24 h, while one anaerobic bottle was positive at 36 h. Escherichia coli and Fusobacterium ulcerans were identified from subcultures by MALDI-TOF MS with a score of 2.02 and 2.35, respectively. The 16S rRNA gene was sequenced in order to confirm the identification of F. ulcerans with a 100% homology to the reference strain. The patient was treated with 4 g/0,5 g of IV piperacillin/tazobactam and later with 1 g/0,2 g of amoxicillin/clavulanic during 7 days with good clinical evolution.

Differences between bloodstream infections involving gram-positive and gram-negative anaerobes

BACKGROUND

The objectives of this study were to describe differences between bloodstream infections involving Gram-positive (GP) and Gram-negative (GN) anaerobic bacteria.

METHODS

Patients with clinically significant anaerobic bacteremia detected between October 2016 and July 2022 in a tertiary hospital in Granada (Spain) were retrospectively included. Species identification was performed by MALDI-TOF MS and/or molecular methods. The association between variables was analyzed using contingency tables, applying the chi-square test when expected frequencies were adequate and the Fisher exact test when not. Variables were gathered at the time of the first positive blood culture.

RESULTS

Out of 237 cases of anaerobic bloodstream infections detected, 127 (53.6%) were GN. Crude mortality was 20.3%, corresponding to 48 patients who died of causes directly attributable to bacteremia. The presence of malignant disease (p = 0.011), abdominal and/or pelvic surgery (p = 0.001), and transplantation (p = 0.008) were significantly associated with bacteremia due to GN bacteria, while the presence of diabetes mellitus was significantly associated with bacteremia due to GP bacteria (p = 0.022). The presence of both septic shock and mortality was more frequently associated with bacteremia due to GN versus GP bacteria.

CONCLUSIONS

The association of certain variables with the presence of bloodstream infections due to GP or GN anaerobic bacteria may assist in selecting the optimal empirical therapeutic approach and improving the outcome of patients with these types of infection.

A Cryptic Case of an Anaerobic Hepatic Abscess Following a Cesarean Section

Postpartum infectious complications can present with a wide range of nonspecific symptoms. Herein, we describe a complicated late postpartum presentation of recurrent fever following a cesarean delivery complicated by chorioamnionitis. Following discharge, the patient experienced cyclical fever and was treated with antipyretics as an outpatient. The patient continued to experience symptoms and reported to the hospital for further evaluation. Initially thought to be septic pelvic thrombophlebitis, the patient was trialed on clindamycin and gentamycin without resolution of symptoms. After extensive evaluation, the fevers were found to be the result of an infected periuterine hematoma and a concomitant subcapsular inferior hepatic abscess. Bacterial cultures isolated two rare anaerobic organisms: Peptoniphilus ssp. and Finegoldia magna. Source control was achieved by drainage of the two abscesses followed by antibiotic treatment with ertapenem and metronidazole, and the patient recovered successfully. This is the first reported case, to the authors' knowledge, of this complicated postpartum picture due to these anaerobic organisms.

Gut Microbiota Composition Can Predict Colonization by Multidrug-Resistant Bacteria in SARS-CoV-2 Patients in Intensive Care Unit: A Pilot Study

The SARS-CoV-2 infection has increased the number of patients entering Intensive Care Unit (ICU) facilities and antibiotic treatments. Concurrently, the multi-drug resistant bacteria (MDRB) colonization index has risen. Considering that most of these bacteria are derived from gut microbiota, the study of its composition is essential. Additionally, SARS-CoV-2 infection may promote gut dysbiosis, suggesting an effect on microbiota composition. This pilot study aims to determine bacteria biomarkers to predict MDRB colonization risk in SARS-CoV-2 patients in ICUs. Seventeen adult patients with an ICU stay >48 h and who tested positive for SARS-CoV-2 infection were enrolled in this study. Patients were assigned to two groups according to routine MDRB colonization surveillance: non-colonized and colonized. Stool samples were collected when entering ICUs, and microbiota composition was determined through Next Generation Sequencing techniques. Gut microbiota from colonized patients presented significantly lower bacterial diversity compared with non-colonized patients (p < 0.05). Microbiota in colonized subjects showed higher abundance of Anaerococcus, Dialister and Peptoniphilus, while higher levels of Enterococcus, Ochrobactrum and Staphylococcus were found in non-colonized ones. Moreover, LEfSe analysis suggests an initial detection of Dialister propionicifaciens as a biomarker of MDRB colonization risk. This pilot study shows that gut microbiota profile can become a predictor biomarker for MDRB colonization in SARS-CoV-2 patients.

Analysis of Neutrophil and Monocyte Inflammation Markers in Response to Gram-Positive Anaerobic Cocci

The impact of anaerobic bacteria on the human host is sparsely investigated due to cultivation challenges. Nonetheless, in the last decade increasing research demonstrated the importance of paying attention to these overlooked pathogens. In this chapter, we provide an overview of analyzing surface and intracellular inflammation markers of neutrophils and monocytes in response to Gram-positive anaerobic cocci (GPAC) species Peptoniphilus (P.) harei.

Epidemiology and outcome of anaerobic bacteremia in a tertiary hospital

Despite a low incidence, anaerobic bacteremia remains a serious and often underestimated condition. This retrospective study aims to describe the epidemiology of anaerobic bacteremia and to identify risk factors affecting mortality and the impact of treatment. We included all positive anaerobic blood cultures from January 2018 to December 2019 at the University Hospital of Charleroi (Belgium). We identified 105 episodes of clinically significant anaerobic bacteremia (mean age of patients: 66.4 +/- 16.8 years). The main comorbidities were hypertension, chronic kidney disease, and diabetes. Bacteremia was community-acquired in 70.5% of the episodes. Two thirds of the blood cultures were mono-microbial, and the commonest bacteria found were Bacteroides fragilis group (31.4%), Fusobacterium spp. (17.1%) and Clostridium spp. (15.2%). The main sources of bacteremia were abdominal (35.2%), urinary (17.1%), osteoarticular (14.2%) and pulmonary (12.3%). Surgery within 30 days before hospitalization was more frequent in patients with nosocomial bacteremia (45.2% vs 2.7%, p &lt; 0.0001). An appropriate empirical antibiotic therapy was initiated in 74.7% of patients, and the median duration of antibiotic therapy was 10 [5 - 15] days. One third of patients had a surgical management. Patients who did not survive at day 30 (n = 23 [21.9%]) had significantly lower time to positivity (TTP) values than patients alive at day 30, presented more often with sepsis, had higher Charlson scores and chronic kidney disease, and were more likely to suffer from Clostridium spp. bacteremia. In a Cox proportional hazard analysis, sepsis (OR: 7.32 [95% CI: 2.83- 18.97], p&lt; 0.0001) was identified as an independent risk factors for 30-day mortality, whereas time to positivity ≥ 30 h (OR: 0.24 [95% CI: 0.07 - 0.84], p = 0.025) and an adequate empirical antibiotic therapy (OR: 0.37 [95% CI: 0.15 - 0.94], p = 0.037) were associated with better outcomes. Anaerobic bacteremia has a high mortality rate which justifies the maintenance of empirical antibiotic therapy.

Peptoniphilus indolicus infection in a pregnant woman: a case report

BACKGROUND

Peptoniphilus indolicus belongs is a gram-positive anaerobic coccus (GPAC), which can cause bacterial vaginitis. However, only a few studies have reported severe infection of P. indolicus. This study presented the first case of severe infection of P. indolicus during pregnancy. It aimed to help to fill the gap in the literature, find out the factors that accelerate infection and discuss the significance of the GPAC test.

CASE PRESENTATION

A 35-year-old woman was admitted due to unbearable abdominal pain with dilation of the cervical opening at 22+ weeks of gestation. A blood test revealed electrolyte disturbance and hypoproteinemia. A day before admission, the patient developed pain in the lower abdomen accompanied by yellow-green vaginal discharge. Two hours after admission, the patient suddenly presented with hyperpyrexia and chills. Timely and adequate antibiotic and cooling treatments were administered. After 14 h, the patient again developed chills that lasted for approximately 20 min, accompanied by uterine contractions and membrane rupture. After 3 h, she had a miscarriage and rapidly developed septic shock. She was transferred to the intensive care unit for further infection control, shock correction, and circulatory stabilization. The cultures of blood, secretion specimen, and amniotic fluid indicated P. indolicus infection using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, an advanced tool for bacterial species identification.

CONCLUSIONS

P. indolicus is an opportunistic pathogen in pregnant women. Poor physical conditions and pregnancy may accelerate disease progression and lead to severe inflammation.

Antibiotic Resistance and Mechanisms of Pathogenic Bacteria in Tubo-Ovarian Abscess

A tubo-ovarian abscess (TOA) is a common type of inflammatory lump in clinical practice. TOA is an important, life-threatening disease, and it has become more common in recent years, posing a major health risk to women. Broad-spectrum antimicrobial agents are necessary to cover the most likely pathogens because the pathogens that cause TOA are polymicrobial. However, the response rate of antibiotic treatment is about 70%, whereas one-third of patients have poor clinical consequences and they require drainage or surgery. Rising antimicrobial resistance serves as a significant reason for the unsatisfactory medical outcomes. It is important to study the antibiotic resistance mechanism of TOA pathogens in solving the problems of multi-drug resistant strains. This paper focuses on the most common pathogenic bacteria isolated from TOA specimens and discusses the emerging trends and epidemiology of resistant Escherichia coli, Bacteroides fragilis, and gram-positive anaerobic cocci. Besides that, new methods that aim to solve the antibiotic resistance of related pathogens are discussed, such as CRISPR, nanoparticles, bacteriophages, antimicrobial peptides, and pathogen-specific monoclonal antibodies. Through this review, we hope to reveal the current situation of antibiotic resistance of common TOA pathogens, relevant mechanisms, and possible antibacterial strategies, providing references for the clinical treatment of drug-resistant pathogens.

Septic Shock, Renal Abscess, and Bacteremia Due to Peptoniphilus asaccharolyticus in a Woman with Nephrosis and Diabetes Mellitus: Case Report and Literature Review

Peptoniphilus asaccharolyticus is a Gram-positive anaerobic coccus, which forms part of the normal flora and the human commensals of the skin, genitourinary system, and gut. It can cause opportunistic infections in immunocompromised patients and is frequently isolated as part of polymicrobial spectra. Severe monomicrobial infections caused by the genus rarely occur. In this study, we report on septic shock, renal abscess, and bacteremia due to P. asaccharolyticus in a woman with nephrosis and diabetes mellitus. To the best of our knowledge, this report is the first to describe P. asaccharolyticus isolated from both renal abscess and blood cultures purely. The underlying diseases of the host and the removal of the double J tube were significant predisposing factors in this infection.

Identification of Peptoniphilus harei From Blood Cultures in an Infected Aortic Aneurysm Patient: Case Report and Review Published Literature

Gram-positive anaerobic cocci (GPAC) are a commensal part of human flora but are also opportunistic pathogens. This is possibly the first study to report a case of Peptoniphilus harei bacteremia in an abdominal aortic aneurysm (AAA) patient. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) failed to identify the isolate and molecular analysis confirmed it as P. harei. A comprehensive literature review revealed that P. harei is an emergent pathogen. This study serves as a reminder for practicing clinicians to include anaerobic blood cultures as part of their blood culture procedures; this is particularly important situations with a high level of suspicion of infection factors in some noninfectious diseases, as mentioned in this publication. Clinical microbiologists should be aware that the pathogenic potential of GPAC can be greatly underestimated leading to incorrect diagnosis on using only one method for pathogen identification. Upgradation and correction of the MALDI-TOF MS databases is recommended to provide reliable and rapid identification of GPAC at species level in medical diagnostic microbiology laboratories.

Sepsis caused by Anaerococcus nagyae after transarterial-chemoembolization for hepatocellular carcinoma: Case report and literature review

Hepatocellular carcinoma (HCC) is more common in patients with chronic viral hepatitis infection and cirrhosis. Transarterial chemoembolization (TACE) is an effective treatment method for unresectable HCC. A rare complication of TACE is the development of bloodstream infection. We present a fatal case of sepsis due to Anaerococcus nagyae after TACE.

In Vitro Antimicrobial Susceptibility Profiles of Gram-Positive Anaerobic Cocci Responsible for Human Invasive Infections

The aim of this multicentre study was to determine the in vitro susceptibility to anti-anaerobic antibiotics of Gram-positive anaerobic cocci (GPAC) isolates responsible for invasive infections in humans. A total of 133 GPAC isolates were collected in nine French hospitals from 2016 to 2020. All strains were identified to the species level (MALDI-TOF mass spectrometry, 16S rRNA sequencing). Minimum inhibitory concentrations (MICs) of amoxicillin, piperacillin, cefotaxime, imipenem, clindamycin, vancomycin, linezolid, moxifloxacin, rifampicin, and metronidazole were determined by the reference agar dilution method. Main erm-like genes were detected by PCR. The 133 GPAC isolates were identified as follows: 10 Anaerococcus spp., 49 Finegoldia magna, 33 Parvimonas micra, 30 Peptoniphilus spp., and 11 Peptostreptococcus anaerobius. All isolates were susceptible to imipenem, vancomycin (except 3 P. micra), linezolid and metronidazole. All isolates were susceptible to amoxicillin and piperacillin, except for P. anaerobius (54% and 45% susceptibility only, respectively). MICs of cefotaxime widely varied while activity of rifampicin, and moxifloxacin was also variable. Concerning clindamycin, 31 were categorized as resistant (22 erm(A) subclass erm(TR), 7 erm(B), 1 both genes and 1 negative for tested erm genes) with MICs from 8 to >32 mg/L. Although GPACs are usually susceptible to drugs commonly used for the treatment of anaerobic infections, antimicrobial susceptibility should be evaluated in vitro.

A tale of two unusual anaerobic bacterial infections in an immunocompetent man: A case report and literature review

We report a case of an immunocompetent man who presented with Desulfovibrio fairfieldensis bacteremia, followed by an epidural abscess due to Parvimonas micra. Only few cases have described unique clinical features related to both organisms, and this report illustrates two distinct sequential, if not concurrent, syndromes due to these anaerobes.

Application of MALDI-TOF MS to assess clinical characteristics, risk factors, and outcomes associated with anaerobic bloodstream infection: a retrospective observational study

Background

Correctly identifying anaerobic bloodstream infections (BSIs) is difficult. However, a new technique, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), enables more accurate identification and appropriate treatment. Anaerobic BSIs identified by MALDI-TOF MS were retrospectively analyzed to determine the clinical and microbiological features and patient outcomes based on the anaerobic genera or group.

Methods

Medical records of patients with anaerobic BSIs were used to conduct a single-center retrospective cohort study from January 2016 to December 2020 in Nagoya, Japan. Multivariate logistic regression analysis was performed to determine the independent risk factors for in-hospital mortality.

Results

Of the 215 patients with anaerobic BSIs, 31 had multiple anaerobic organisms in the blood culture, including 264 total episodes of anaerobic BSIs. Bacteroides spp. were isolated the most (n = 74), followed by gram-positive non-spore-forming bacilli (n = 57), Clostridium spp. (n = 52), gram-positive anaerobic cocci (GPAC) (n = 27), and gram-negative cocci (n = 7). The median patient age was 76 years; 56.7% were male. The most common focal infection site was intra-abdominal (36.7%). The in-hospital mortality caused by anaerobic BSIs was 21.3%, and was highest with Clostridium spp. (36.5%) and lowest with GPAC (3.7%). Age, solid tumors, and Clostridium spp. were independent risk factors for in-hospital mortality.

Conclusions

We identified current anaerobic BSI trends using MALDI-TOF MS and reported that mortality in patients with anaerobic BSIs patients was highest with Clostridium spp. infections.

Multiple hepatic and brain abscesses caused by Parvimonas micra: A case report and literature review

Gram-positive anaerobic cocci (GPAC) are responsible for 30% of anaerobic infections. Parvimonas micra is an emergent pathogen that is part of the oral and gastrointestinal commensal flora, and its role in several infection processes has recently emerged thanks to the improvement of diagnostic techniques. P. micra bacteraemia is reported in immunocompromised patients and is often complicated by abscesses. Here, we present a case study of multiple hepatic and brain abscesses caused by P. micra bacteraemia in a patient with complicated diverticulitis.

Clinical Characteristics of Chronic Lung Abscess Associated with Parvimonas micra Diagnosed Using Metagenomic Next-Generation Sequencing

Purpose

Parvimonas micra (P. micra) is a Gram-positive anaerobic bacterium distributed in the oral cavity, with a potential to become pathogenic causing lung abscess. Due to the lack of specificity of symptoms and the difficulty in culture, the diagnosis of lung abscess associated with P. micra is delayed. It is essential to elucidate the clinical characteristics of lung abscess associated with P. micra.

Methods

From January 2019 to July 2020, five patients with chronic lung abscess associated with P. micra diagnosed by pathological biopsy and metagenomic next-generation sequencing (mNGS) were analyzed in this retrospective study.

Results

Among the five patients, four had a history of smoking, three had periodontitis, and two had a history of drinking. The average course of the disease was 6.5 months. High-density flake-like or mass shadows with irregular boundaries were observed in the chest computed tomography (CT) images of the five patients, and liquefactive necrosis was detected in the middle of the lesions; however, no gas-liquid plane or cavity was noted, making it difficult to distinguish a lung cancer. The pathological biopsy of the five patients showed chronic inflammation of lung tissue, and P. micra was detected by mNGS in the biopsy or bronchoalveolar lavage fluid samples. Two patients were treated with amoxicillin-clavulanate, two had metronidazole, and one had moxifloxacin. Among them, four recovered after receiving antibiotic treatment, and the remaining one underwent surgical resection due to poor antibiotic treatment effect.

Conclusion

Chronic lung abscess associated with P. micra, common in elderly male smokers with poor oral hygiene, is often diagnosed in a delayed manner and misdiagnosed as lung cancer. The mNGS technology is beneficial to the rapid determination of P. micra.

Healthcare-Associated Laboratory-Confirmed Bloodstream Infections-Species Diversity and Resistance Mechanisms, a Four-Year Retrospective Laboratory-Based Study in the South of Poland

INTRODUCTION

Regardless of the country, advancements in medical care and infection prevention and control of bloodstream infections (BSIs) are an enormous burden of modern medicine.

OBJECTIVES

The aim of our study was to describe the epidemiology and drug-resistance of laboratory-confirmed BSI (LC-BSIs) among adult patients of 16 hospitals in the south of Poland.

PATIENTS AND METHODS

Data on 4218 LC-BSIs were collected between 2016-2019. The identification of the strains was performed using MALDI-TOF. Resistance mechanisms were investigated according to European Committee on Antimicrobial Susceptibility Testing, EUCAST recommendations.

RESULTS

Blood cultures were collected from 8899 patients, and LC-BSIs were confirmed in 47.4%. The prevalence of Gram-positive bacteria was 70.9%, Gram-negative 27.8% and yeast 1.4%. The most frequently isolated genus was Staphylococcus (50% of all LC-BSIs), with a domination of coagulase-negative staphylococci, while Escherichia coli (13.7%) was the most frequent Gram-negative bacterium. Over 4 years, 108 (2.6%) bacteria were isolated only once, including species from the human microbiota as well as environmental and zoonotic microorganisms. The highest methicillin resistant Staphylococcus aureus (MRSA) prevalence was in intensive care units (ICUs) (55.6%) but S. aureus with resistance to macrolides, lincosamides and streptogramins B (MLSB) in surgery was 66.7%. The highest prevalence of E. faecalis with a high-level aminoglycoside resistance (HLAR) mechanism was in ICUs, (84.6%), while E. faecium-HLAR in surgery was 83.3%. All cocci were fully glycopeptide-sensitive. Carbapenem-resistant Gram-negative bacilli were detected only in non-fermentative bacilli group, with prevalence 70% and more.

CONCLUSIONS

The BSI microbiology in Polish hospitals was similar to those reported in other studies, but the prevalence of MRSA and enterococci-HLAR was higher than expected, as was the prevalence of carbapenem-resistant non-fermentative bacilli. Modern diagnostic techniques, such as MALDI-TOF, guarantee reliable diagnosis.

Microecological investigation and comparison of two clinical methods to evaluate axillary osmidrosis

Axillary osmidrosis (AO) is a common disease that causes patients to develop malodor and occurs worldwide. There is a lack of uniform standards to evaluate the severity of the odor and identify a sensitive and convenient method to determine the therapeutic effect of AO treatments in a clinical setting. In the present study, the association between pH value and disease severity was investigated and the potential pathogenic bacteria and probiotic pathogens of AO were further examined. A total of 32 patients with bilateral AO and 32 normal healthy controls were recruited for the present study. The odor was investigated using the traditional method (TM) and our groups newly developed Lu swab method (LSM) and according to the results, the cases were assigned a score on a 4-point scale. The patients' scores and pH value were recorded. The microbiological compositions of the affected sites were determined using 16S rDNA sequencing. The mean LSM score was higher compared with the mean TM score (P<0.05). Furthermore, the mean axillary pH value was higher in patients with AO compared with that in healthy subjects (P<0.0001), and the mean pH value of patients with high disease severity was higher compared with that in patients with moderate disease severity (P<0.001). In the microecological flora, the proportion of Staphylococcus species on patients with AO was significantly lower compared with that on normal controls (P<0.0001), while the proportion of Corynebacterium and Anaerococcus was significantly higher compared with that on normal controls (P<0.01 and P<0.001, respectively). In conclusion, LSM provided a higher sensitivity for evaluating odor severity than the TM and may be suitable for use in a clinical setting. The pH value was positively associated with AO severity. Staphylococcus may be an appropriate probiotic for the treatment of AO, while Corynebacterium and Anaerococcus may be causative pathogens of AO. The present study was registered in the Chinese Clinical Trial Registry (registration no. ChiCTR2000037275).

A rare case of emphysematous pyelonephritis caused by Candida parapsilosis and Finegoldia magna complicated by medical care avoidance

Emphysematous pyelonephritis (EPN) is a necrotizing gas producing infection of the renal parenchyma that commonly occurs in patients with diabetes. EPN requires early diagnosis and treatment due to the possible life-threatening septic complications. We report a rare case of EPN caused by an unfavorable mixed infection of Candida parapsilosis and Finegoldia magna. To our knowledge, this is the first reported case of EPN caused by Finegoldia magna. A 62-year-old male with diabetes mellitus (DM) presented with abdominal pain, shortness of breath, and nausea in which a diagnosis of septic shock was made due to EPN. Our patient first noticed abdominal pain 3 weeks prior to hospital presentation; however, he avoided getting treatment due to a fear of contracting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This patient exhibited deterioration and expired after surgical intervention despite uneventful nephrectomy. This case suggests that medical care avoidance behaviors among patients could potentially complicate their clinical course.

Clinical characteristics of bloodstream infection by Parvimonas micra: retrospective case series and literature review

Background

Gram-positive anaerobic (GPA) bacteria inhabit different parts of the human body as commensals but can also cause bacteremia. In this retrospective observational study, we analyzed GPA bacteremia pathogens before (2013–2015) and after (2016–2018) the introduction of the matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS).

Method

We conducted a retrospective observational study by searching the microbiology database to identify all positive GPA blood cultures of patients with GPA bacteremia diagnosed using the new technique, MALDI-TOF MS, between January 1, 2016 and December 31, 2018; and using a conventional phenotypic method between January 1, 2013 and December 31, 2015 at a single tertiary center in Japan. Parvimonas micra (P. micra) (17.5%) was the second most frequently identified GPA (MALDI-TOF MS); we then retrospectively reviewed electronic medical records for 25 P. micra bacteremia cases at our hospital. We also conducted a literature review of published cases in PubMed from January 1, 1980, until December 31, 2019; 27 cases were retrieved.

Results

Most cases of P. micra bacteremia were identified after 2015, both, at our institute and from the literature review. They were of mostly elderly patients and had comorbid conditions (malignancies and diabetes). In our cases, laryngeal pharynx (7/25, 28%) and gastrointestinal tract (GIT; 6/25, 24%) were identified as the most likely sources of bacteremia; however, the infection source was not identified in 9 cases (36%). P. micra bacteremia were frequently associated with spondylodiscitis (29.6%), oropharyngeal infection (25.9%), intra-abdominal abscess (14.8%), infective endocarditis (11.1%), septic pulmonary emboli (11.1%), and GIT infection (11.1%) in the literature review. Almost all cases were treated successfully with antibiotics and by abscess drainage. The 30-day mortalities were 4 and 3.7% for our cases and the literature cases, respectively.

Conclusions

Infection sites of P. micra are predominantly associated with GIT, oropharyngeal, vertebral spine, intra-abdominal region, pulmonary, and heart valves. Patients with P. micra bacteremia could have good prognosis following appropriate treatment.

Relevance of anaerobic bacteremia in adult patients: A never-ending story?

Obligate anaerobic bacteria are considered important constituents of the microbiota of humans; in addition, they are also important etiological agents in some focal or invasive infections and bacteremia with a high level of mortality. Conflicting data have accumulated over the last decades regarding the extent in which these pathogens play an intrinsic role in bloodstream infections. Clinical characteristics of anaerobic bloodstream infections do not differ from bacteremia caused by other pathogens, but due to their longer generation time and rigorous growth requirements, it usually takes longer to establish the etiological diagnosis. The introduction of matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) has represented a technological revolution in microbiological diagnostics, which has allowed for the fast, accurate and reliable identification of anaerobic bacteria at a low sample cost. The purpose of this review article is to summarize the currently available literature data on the prevalence of anaerobic bacteremia in adults for physicians and clinical microbiologists and to shed some light on the complexity of this topic nowadays.

Anaerobic blood culture positivity at a University Hospital in Hungary: A 5-year comparative retrospective study

Anaerobic bacteremia (AB) is usually detected in about 0.5-13% of positive blood cultures. The aim of this study was to determine prevalence of anaerobic bacteremia over a 5-year period (2013-2017), to identify current trends at our University Hospital and to compare the results to those in a similar study (2005-2009) in the same region. During the study period, an average of 23,274 ± 2,756 blood cultures were received per year. Out of the positive blood cultures, 3.3-3.6% (n = 423) yielded anaerobic bacteria, representing 3.5-3.8 anaerobic isolates/1000 blood culture bottles (including both aerobic and anaerobic bottles) per year for hospitalized patients. Mean age of affected patients was 70-73 years (range: 18-102 years) with a male-to-female ratio: 0.60. Most isolated anaerobes were Cutibacterium spp. (54.0 ± 8.5%; n = 247), while among anaerobes other than Cutibacterium spp., Bacteroides and Parabacteroides and Clostridium spp. were the most prevalent. Blood culture time-to-positivity (TTP) for clinically relevant bacteria was 31.4 ± 23.4 h, while for Cutibacterium spp., TTP values were 112.9 ± 37.2 h (p < 0.0001). In conclusion, the prevalence of anaerobic bacteremia should be determined on institutional basis.