Hungatella hathewayi bacteremia due to acute appendicitis: A case report and a narrative review.

Hungatella species, including Hungatella hathewayi and Hungatella effluvii, previously identified as part of the Clostridium genus, are anaerobic bacteria primarily residing in the gut microbiome, with infrequent implications in human infections. This article presents the case of an 87-year-old Asian male admitted for a hyperosmolar hyperglycemic state with septic shock secondary to Hungatella hathewayi bacteremia originating from acute appendicitis. Remarkably, the bacterium was detected in the blood 48 hours before the emergence of clinical and radiographic evidence of acute appendicitis. Additionally, we conducted a literature review to identify all documented human infections caused by Hungatella species. Timely microbial identification in such cases is essential for implementing targeted antibiotic therapy and optimizing clinical outcomes.

Use of pus metagenomic next-generation sequencing for efficient identification of pathogens in patients with sepsis.

The positive detection rate of blood metagenomic next-generation sequencing (mNGS) was still too low to meet clinical needs, while pus from the site of primary infection may be advantageous for identification of pathogens. To assess the value of mNGS using pus in patients with sepsis, thirty-five samples were collected. Pathogen identification and mixed infection diagnosis obtained by use of mNGS or cultivation methods were compared. Fifty-three aerobic or facultative anaerobes, 59 obligate anaerobes and 7 fungi were identified by the two methods. mNGS increased the accuracy rate of diagnosing aerobic or facultative anaerobic infections from 44.4% to 94.4%; mNGS also increased the sensitivity of diagnosing obligate anaerobic infections from 52.9% to 100.0%; however, mNGS did not show any advantage in terms of fungal infections. Culture and mNGS identified 1 and 24 patients with mixed infection, respectively. For obligate anaerobes, source of microorganisms was analyzed. The odontogenic bacteria all caused empyema (n = 7) or skin and soft tissue infections (n = 5), whereas the gut-derived microbes all caused intra-abdominal infections (n = 7). We also compared the clinical characteristics of non-obligate anaerobic and obligate anaerobic infection groups. The SOFA score [9.0 (7.5, 14.3) vs. 5.0 (3.0, 8.0), P = 0.005], procalcitonin value [4.7 (1.8, 39.9) vs. 2.50 (0.7, 8.0), P = 0.035], the proportion of septic shock (66.7% vs. 35.3%, P = 0.044) and acute liver injury (66.7% vs. 23.5%, P = 0.018) in the non-obligate anaerobic infection group were significantly higher than those in the obligate anaerobic infection group. In patients with sepsis caused by purulent infection, mNGS using pus from the primary lesion may yield more valuable microbiological information.

Unbridled Threat of Gas Gangrene in a Patient With Uncontrolled Diabetes Mellitus: A Compelling Case Report of Clostridium perfringens Infection.

Clostridium perfringens, a Gram-positive anaerobic bacterium, is well-known for its association with gas gangrene, a severe and rapidly progressing infection characterized by tissue gas production and necrosis. In this case report, we present the instance of a 64-year-old male with poorly controlled diabetes mellitus who developed a C. perfringens-related infection following a traumatic foot wound. The report emphasizes the critical significance of early diagnosis and aggressive treatment in C. perfringens infections, particularly in patients with underlying risk factors. Detailed accounts of clinical findings, laboratory results, computed tomography, and surgical interventions are provided. A multidisciplinary approach proved essential for successful management. The inherent scholarly value of this case is substantiated by its meticulous documentation of the clinical trajectory, diagnostic modalities, and treatment modalities employed. The intricate collaboration across diverse medical disciplines, the uncommon manifestation of the infection following a traumatic foot wound, and the favorable outcome achieved through prompt and multidisciplinary intervention collectively contribute to the exceptional nature and didactic significance of this case. The dissemination of such clinical experiences assumes paramount importance in advancing medical scholarship, cultivating awareness, and engendering a profound comprehension of the complexities associated with C. perfringens infections, thereby enriching the wider scientific and medical community.

Metronidazole prescribing practices in Australian hospitals: Measuring guideline compliance and appropriateness to support antimicrobial stewardship.

BACKGROUND: Metronidazole is a commonly prescribed antimicrobial in Australian hospitals. Inappropriate use may increase risks to patient care, such as toxicities and antimicrobial resistance. To date, there is limited information on the quality of metronidazole prescriptions to inform antimicrobial stewardship and quality improvement initiatives. This study aims to describe the quality of metronidazole prescribing practices in Australian hospitals. METHODS: Retrospective data analysis of the Hospital National Antimicrobial Prescribing Survey (Hospital NAPS). Data were collected by auditors at each participating hospital using a standardised auditing tool. All data from 2013 to 2021 were de-identified and analysed descriptively. Variables included were antimicrobial prescribed, indication, guideline compliance and appropriateness. RESULTS: Metronidazole was the fifth most prescribed antimicrobial in the Hospital NAPS dataset (2013-2021), accounting for 5.7 % (n = 14,197) of all antimicrobial prescriptions (n = 250,863). The proportion of metronidazole prescriptions declined by 2 % from 2013 to 2021 (p < 0.001). The most common indications were surgical prophylaxis (15.3 %), diverticulitis (9.4 %), aspiration pneumonia (7.3 %). Over half (53.5 %) of metronidazole prescriptions were deemed compliant with prescribing guidelines and 67.8 % were deemed appropriate. These rates were comparatively lower than the overall results of all antimicrobials. The primary documented reason for inappropriateness was that the spectrum was too broad (34.2 %). Surgical prophylaxis had the lowest rates of guideline compliance (53.8 %) and appropriateness (54.3 %). CONCLUSIONS: Metronidazole remains widely used in Australian hospitals with suboptimal rates of guideline compliance and appropriateness. A noted area for improvement that we identified was using metronidazole when its spectrum was too broad, possibly when anaerobic therapy is unnecessary. With increasing international adoption of the Hospital NAPS programme, future comparative studies will be critical to identify global trends of antimicrobial prescribing quality. Antimicrobial stewardship (AMS) programmes have proven to be effective in improving prescribing quality and should be considered to specifically target improvements in metronidazole prescribing.

A rare anaerobic cause of vertebral osteomyelitis and psoas abscess: A case study.

Parvimonas micra is an obligate anaerobe that forms part of the normal gastrointestinal flora. The advent of matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF) and 16s ribosomal RNA gene sequencing has led to increased detection of many rare anaerobic isolates, including Parvimonas micra. Typical risk factors for Parvimonas micra bacteremia include dental procedures or spinal instrumentation. Here, we report a case of Parvimonas micra spondylodiscitis and psoas abscess in a patient with no obvious antecedent risk factors and explore the challenges in isolation of the organism from tissue samples.

First periprosthetic hip infection caused by Eggerthella lenta.

Periprosthetic joint infection (PJI) caused by anaerobic, Gram-positive bacilli is rare. We present here a case of an 83-year-old female patient who was admitted to our tertiary referral arthroplasty center to treat a complex PJI of her right hip joint after multiple failed surgeries. External and intraoperative cultures reveald growth of Eggerthella lenta (E. lenta). Microbiological identification was fast but in a very few samples. A successful management, comprising of radical debridement with one-stage exchange and an antibiotic treatment with multiple antibiotics, has been achieved at 24-month follow-up. To the best of our knowledge, we have provided the first case study of a hip PJI caused by E. lenta successfully treated with one-stage exchange and an adequate antibiotic treatment.

Actinomyces europaeus as an emerging cause of necrotizing fasciitis.

Necrotizing fasciitis is a type of necrotizing soft tissue infection (NSTI) that can be polymicrobial or monomicrobial in origin. Polymicrobial infections typically involve anaerobes of the Clostridium or Bacteroides family. This case report highlights necrotizing fasciitis caused by an unusual culprit, Actinomyces europaeus, which is a gram-positive anaerobic filamentous bacillus that has only been documented in one prior report to cause NSTI. Currently, about half of the hospitals in the United States are equipped to perform antibiotic susceptibility testing for anaerobes, but less than one-quarter of hospitals actually utilize these tests routinely. Thus, it is common for polymicrobial actinomycoses to be blindly treated with antibiotics that are beta-lactamase resistant and active against anaerobes, such as with piperacillin-tazobactam. Here we examine the potential impact of this lack of testing, as well as the evolution of A. europaeus to cause necrotizing fasciitis.

Microbiological Characterization of Actinotignum schaalii Strains Causing Invasive Infections during a Multiyear Period in a Large Canadian Health Care Region.

Actinotignum schaalii is an underrecognized Gram-positive bacillus that is associated with urinary tract infections and cutaneous abscesses. The role of A. schaalii in invasive infections continues to be unappreciated because the bacteria can be isolated from a diverse spectrum of clinical specimens, ranging from being a single pathogen in urine and blood cultures to being deemed a colonizer in polymicrobial anaerobic cultures of sterile fluids and tissues. We conducted a microbiological analysis of clinical isolates obtained from 2012 through 2019. A total of 86 isolates were analyzed; 37 (43%) were from blood cultures, 35 (41%) were from deep wounds and abscesses, 6 (7%) were from urine samples, and the rest were recovered from peritoneal, kidney, and scrotal fluid samples. Urinary tract infections were clinically identified as the source of most cases of bacteremia, although no simultaneous urine cultures yielded positive results. The 16S rRNA gene sequences were available for 32 isolates (37%). Phylogenetic analysis revealed that AS.1/AS.2 strains caused a larger proportion of bloodstream infections (BSIs) (100% versus 52% [P = 0.01]) and trended toward a higher rate of hospitalization (91% versus 76% [P = 0.18]) but had a lower clindamycin MIC90 (0.12 versus >256 µg/mL). Our study emphasizes the emergence of A. schaalii as a pathogen in human urine samples, BSIs, and skin and soft tissue infections. It highlights the pitfalls of current laboratory methods in recovering and identifying this organism from clinical specimens, particularly urine samples. Phylogenetic analysis showed unique genotypic sequences for A. schaalii AS.1/AS.2 strains causing urosepsis, which requires further study to identify potential virulence factors. IMPORTANCE Actinotignum schaalii is an underrecognized Gram-positive bacillus due to its special growth requirements and prior phenotypic identification methods, and it is often mistaken as a contaminant. It has been associated with various clinical syndromes, from urinary tract infections to cutaneous infections. The widespread use of molecular diagnostic methods allowed for improved detection. However, its role in invasive infections remains underappreciated. We conducted a detailed microbiological analysis to improve our understanding of this organism's genotypic and phenotypic characteristics. Our results highlight the pitfalls of clinical laboratory recovery, particularly from urine cultures. Although most BSIs were caused by urinary tract infections, no simultaneous urine cultures identified A. schaalii, largely due to the failure of phenotypic methods to reliably isolate and identify this organism. Additionally, this is the first study demonstrating A. schaalii strains with differences in clinical and microbiological characteristics, raising the possibility of potential bacterial virulence factors contributing to invasive infections.

Development of multiplex PCR panel for detection of anaerobic bacteria in clinical samples.

OBJECTIVE: Although anaerobic bacteria are important agents of a wide variety of serious infections, they are overlooked often in the etiology of infection due to difficulties in isolation and detection. The aim of this study was to develop a new multiplex PCR panel that could detect Bacteroides, Fusobacterium, Prevotella, Veillonella, Clostridium, Peptostreptococcus, and Actinomyces bacteria, which are the most frequently isolated from anaerobic infections, at the genus level. METHOD: Aerobic and anaerobic cultures were performed on 46 clinical specimens, with suspicion of anaerobic infection and were sent to the laboratory. DNA isolation was performed with the same samples and anaerobic bacteria were detected by the multiplex PCR test developed in the study. RESULT: The analytical sensitivity of the multiplex PCR assay was found to be 1-103 CFU/ml, depending on the bacterial species. In this study, anaerobic growth was observed in eight (17.4%) of 46 clinical samples. The multiplex PCR test detected 35 anaerobic bacteria from 20 (43.5%) of 46 clinical samples. The most common anaerobes isolated from clinical specimens by the multiplex PCR assay were Prevotella spp. (37.1%) and Fusobacterium spp. (22.9%) while Clostridium spp. (14.3%), Peptostreptococcus spp. (11.4%), Bacteroides spp. (8.6%), and Veillonella spp. (5.7%) followed these genera. CONCLUSION: As a result, it was concluded that the multiplex PCR panel developed in this study eliminates problems in the detection of anaerobes based on culture, provides more accurate detection of anaerobic bacteria from clinical specimens, takes a shorter time, and allows more accurate infection treatment.

A tale of two habitats: Bacteroides fragilis, a lethal pathogen and resident in the human gastrointestinal microbiome.

Bacteroides fragilis is an obligately anaerobic Gram-negative bacterium and a major colonizer of the human large colon where Bacteroides is a predominant genus. During the growth of an individual clonal population, an astonishing number of reversible DNA inversion events occur, driving within-strain diversity. Additionally, the B. fragilis pan-genome contains a large pool of diverse polysaccharide biosynthesis loci, DNA restriction/modification systems and polysaccharide utilization loci, which generates remarkable between-strain diversity. Diversity clearly contributes to the success of B. fragilis within its normal habitat of the gastrointestinal (GI) tract and during infection in the extra-intestinal host environment. Within the GI tract, B. fragilis is usually symbiotic, for example providing localized nutrients for the gut epithelium, but B. fragilis within the GI tract may not always be benign. Metalloprotease toxin production is strongly associated with colorectal cancer. B. fragilis is unique amongst bacteria; some strains export a protein >99 % structurally similar to human ubiquitin and antigenically cross-reactive, which suggests a link to autoimmune diseases. B. fragilis is not a primary invasive enteric pathogen; however, if colonic contents contaminate the extra-intestinal host environment, it successfully adapts to this new habitat and causes infection; classically peritoneal infection arising from rupture of an inflamed appendix or GI surgery, which if untreated, can progress to bacteraemia and death. In this review selected aspects of B. fragilis adaptation to the different habitats of the GI tract and the extra-intestinal host environment are considered, along with the considerable challenges faced when studying this highly variable bacterium.

Cyanobacteria-based self-oxygenated photodynamic therapy for anaerobic infection treatment and tissue repair.

Photodynamic therapy (PDT) is an important technique to deal with drug-resistant bacterial infections in the post-antibiotic era. However, the hypoxic environment in intractable infections such as refractory keratitis and periodontitis, makes PDT more difficult. In this work, spontaneous oxygen-producing cyanobacteria were used as the carrier of photosensitizer (Ce6), and ultrasmall Cu5.4O nanoparticles (Cu5.4O USNPs) with catalase activity for infection and inflammation elimination and rapid tissue repair (CeCycn-Cu5.4O). The loading of Ce6 and Cu5.4O USNPs onto cyanobacteria surface were confirmed by transmission electron microscopy, nano particle size analyzer, scanning electron microscopy. In vitro sterilization and biofilm removal experiments demonstrated that the restriction of hypoxic environment to PDT was significantly alleviated due to the oxygen production of cyanobacteria. Under laser irradiation, the close transfer of energy photons to oxygen produced by cyanobacteria reduced more than 90% of Ce6 dosages (660 nm, 200 mW/cm2, 2 min). It is worth mentioning that both rapid sterilization through PDT and long-term oxidized free radicals elimination were achieved by adjusting the ratio of Ce6 and Cu5.4O USNPs. Both periodontitis and refractory keratitis animal models proved the excellent self-oxygenation enhanced antibacterial property and promotion of tissue repair.

Porphyromonas pasteri and Prevotella nanceiensis in the sputum microbiota are associated with increased decline in lung function in individuals with cystic fibrosis.

Although anaerobic bacteria exist in abundance in cystic fibrosis (CF) airways, their role in disease progression is poorly understood. We hypothesized that the presence and relative abundance of the most prevalent, live, anaerobic bacteria in sputum of adults with CF were associated with adverse clinical outcomes. This is the first study to prospectively investigate viable anaerobic bacteria present in the sputum microbiota and their relationship with long-term outcomes in adults with CF. We performed 16S rRNA analysis using a viability quantitative PCR technique on sputum samples obtained from a prospective cohort of 70 adults with CF and collected clinical data over an 8 year follow-up period. We examined the associations of the ten most abundant obligate anaerobic bacteria present in the sputum with annual rate of FEV1 change. The presence of Porphyromonas pasteri and Prevotella nanceiensis were associated with a greater annual rate of FEV1 change; -52.3 ml yr-1 (95 % CI-87.7;-16.9), -67.9 ml yr-1 (95 % CI-115.6;-20.1), respectively. Similarly, the relative abundance of these live organisms were associated with a greater annual rate of FEV1 decline of -3.7 ml yr-1 (95 % CI: -6.1 to -1.3, P=0.003) and -5.3 ml yr-1 (95 % CI: -8.7 to -1.9, P=0.002) for each log2 increment of abundance, respectively. The presence and relative abundance of certain anaerobes in the sputum of adults with CF are associated with a greater rate of long-term lung function decline. The pathogenicity of anaerobic bacteria in the CF airways should be confirmed with further longitudinal prospective studies with a larger cohort of participants.

Clinical Relevance of the Microbiome in Odontogenic Abscesses.

Odontogenic abscesses are usually caused by bacteria of the oral microbiome. However, the diagnostic culture of these bacteria is often prone to errors and sometimes fails completely due to the fastidiousness of the relevant bacterial species. The question arises whether additional pathogen diagnostics using molecular methods provide additional benefits for diagnostics and therapy. Experimental 16S rRNA gene analysis with next-generation sequencing (NGS) and bioinformatics was used to identify the microbiome of the pus in patients with severe odontogenic infections and was compared to the result of standard diagnostic culture. The pus microbiome was determined in 48 hospitalized patients with a severe odontogenic abscess in addition to standard cultural pathogen detection. Cultural detection was possible in 41 (85.42%) of 48 patients, while a pus-microbiome could be determined in all cases. The microbiomes showed polymicrobial infections in 46 (95.83%) cases, while the picture of a mono-infection occurred only twice (4.17%). In most cases, a predominantly anaerobic spectrum with an abundance of bacteria was found in the pus-microbiome, while culture detected mainly Streptococcus, Staphylococcus, and Prevotella spp. The determination of the microbiome of odontogenic abscesses clearly shows a higher number of bacteria and a significantly higher proportion of anaerobes than classical cultural methods. The 16S rRNA gene analysis detects considerably more bacteria than conventional cultural methods, even in culture-negative samples. Molecular methods should be implemented as standards in medical microbiology diagnostics, particularly for the detection of polymicrobial infections with a predominance of anaerobic bacteria.

Microbiome of Odontogenic Abscesses.

Severe odontogenic abscesses are regularly caused by bacteria of the physiological oral microbiome. However, the culture of these bacteria is often prone to errors and sometimes does not result in any bacterial growth. Furthermore, various authors found completely different bacterial spectra in odontogenic abscesses. Experimental 16S rRNA gene next-generation sequencing analysis was used to identify the microbiome of the saliva and the pus in patients with a severe odontogenic infection. The microbiome of the saliva and the pus was determined for 50 patients with a severe odontogenic abscess. Perimandibular and submandibular abscesses were the most commonly observed diseases at 15 (30%) patients each. Polymicrobial infections were observed in 48 (96%) cases, while the picture of a mono-infection only occurred twice (4%). On average, 31.44 (±12.09) bacterial genera were detected in the pus and 41.32 (±9.00) in the saliva. In most cases, a predominantly anaerobic bacterial spectrum was found in the pus, while saliva showed a similar oral microbiome to healthy individuals. In the majority of cases, odontogenic infections are polymicrobial. Our results indicate that these are mainly caused by anaerobic bacterial strains and that aerobic and facultative anaerobe bacteria seem to play a more minor role than previously described by other authors. The 16S rRNA gene analysis detects significantly more bacteria than conventional methods and molecular methods should therefore become a part of routine diagnostics in medical microbiology.

What we actually know about the pathogenicity of Bacteroides pyogenes.

The aim of the study was to evaluate the pathogenic potential of Bacteroides pyogenes, rarely identified in clinical laboratories anaerobic bacteria. To increase the knowledge about this poorly understood anaerobic microorganism, the study also includes cases of infections described so far in the literature. Only the use of 16S rRNA sequencing and mass spectrometry technique allowed the identification of B. pyogenes from clinical specimens. We reported 13 severe human infections caused by B. pyogenes. Bacteria were cultured from the wound after biting by animals, chronic infections within the oral cavity, from patients with histologically or radiological proven osteomyelitis, surgical site infection, and from urine sample collected after a urological procedure. Most (9/13) of the patients required hospitalization. Almost 70% of them needed urgent admission via the emergency room. Two inpatients due to a life-threatening condition were admitted to the intensive care unit. Almost 50% of isolates were resistant to penicillin. All resistant to penicillin strains were isolated from skin and mucous membrane infections.

Hyperbaric oxygen treatment is associated with a decrease in cytokine levels in patients with necrotizing soft-tissue infection.

BACKGROUND: The pathophysiological understanding of the inflammatory response in necrotizing soft-tissue infection (NSTI) and its impact on clinical progression and outcomes are not resolved. Hyperbaric oxygen (HBO2 ) treatment serves as an adjunctive treatment; however, its immunomodulatory effects in the treatment of NSTI remains unknown. Accordingly, we evaluated fluctuations in inflammatory markers during courses of HBO2 treatment and assessed the overall inflammatory response during the first 3 days after admission. METHODS: In 242 patients with NSTI, we measured plasma TNF-α, IL-1ß, IL-6, IL-10, and granulocyte colony-stimulating factor (G-CSF) upon admission and daily for three days, and before/after HBO2 in the 209 patients recieving HBO2 . We assessed the severity of disease by Simplified Acute Physiology Score (SAPS) II, SOFA score, and blood lactate. RESULTS: In paired analyses, HBO2 treatment was associated with a decrease in IL-6 in patients with Group A-Streptococcus NSTI (first HBO2 treatment, median difference -29.5 pg/ml; second HBO2 treatment, median difference -7.6 pg/ml), and overall a decrease in G-CSF (first HBO2 treatment, median difference -22.5 pg/ml; 2- HBO2 treatment, median difference -20.4 pg/ml). Patients presenting with shock had significantly higher baseline cytokines values compared to non-shock patients (TNF-α: 51.9 vs. 23.6, IL-1ß: 1.39 vs 0.61, IL-6: 542.9 vs. 57.5, IL-10: 21.7 vs. 3.3 and G-CSF: 246.3 vs. 11.8 pg/ml; all p < 0.001). Longitudinal analyses demonstrated higher concentrations in septic shock patients and those receiving renal-replacement therapy. All cytokines were significantly correlated to SAPS II, SOFA score, and blood lactate. In adjusted analysis, high baseline G-CSF was associated with 30-day mortality (OR 2.83, 95% CI: 1.01-8.00, p = 0.047). CONCLUSION: In patients with NSTI, HBO2 treatment may induce immunomodulatory effects by decreasing plasma G-CSF and IL-6. High levels of inflammatory markers were associated with disease severity, whereas high baseline G-CSF was associated with increased 30-day mortality.

The Prevalence and Clinical Significance of Anaerobic Bacteria in Major Liver Resection.

(1) Background: Anaerobic infections in hepatobiliary surgery have rarely been addressed. Whereas infectious complications during the perioperative phase of liver resections are common, there are very limited data on the prevalence and clinical role of anaerobes in this context. Given the risk of contaminated bile in liver resections, the goal of our study was to investigate the prevalence and outcome of anaerobic infections in major hepatectomies. (2) Methods: We retrospectively analyzed the charts of 245 consecutive major hepatectomies that were performed at the department of General, Visceral, and Transplantation Surgery of the University Hospital of Tuebingen between July 2017 and August 2020. All microbiological cultures were screened for the prevalence of anaerobic bacteria and the patients' clinical characteristics and outcomes were evaluated. (3) Results: Of the 245 patients, 13 patients suffered from anaerobic infections. Seven had positive cultures from the biliary tract during the primary procedure, while six had positive culture results from samples obtained during the management of complications. Risk factors for anaerobic infections were preoperative biliary stenting (p = 0.002) and bile leaks (p = 0.009). All of these infections had to be treated by intervention and adjunct antibiotic treatment with broad spectrum antibiotics. (4) Conclusions: Anaerobic infections are rare in liver resections. Certain risk factors trigger the antibiotic coverage of anaerobes.

Clinical Presentation and Incidence of Anaerobic Bacteria in Surgically Treated Biliary Tract Infections and Cholecystitis.

(1) Background: Cholecystitis and cholangitis are among the most common diseases treated by general surgery. Gallstones lead to inflammation and bacterial infection of the biliary tract. Biliary infections can lead to live threatening bacteremia and liver abscesses. The true role of anaerobes remains unclear. (2) Methods: We retrospectively analyzed bacterial cultures from biliary samples obtained from bile ducts and gallbladders at our tertiary care center. Patient characteristics and clinical outcomes were analyzed. (3) Results: In our database of 1719 patients, 365 patients had microbial testing, of which 42 grew anaerobic bacteria. Anaerobes were more frequently cultured in patients with hepatic abscesses and gallbladder perforation. These patients were older and had more comorbidities than the control group. The overall outcomes of all patients were favorable and the resistance rate to commonly used antibiotics remained low. (4) Conclusions: Anaerobes in biliary tract infections appear to be underdiagnosed and more prevalent in the elderly with advanced disease. Due to low antibiotic resistance, the combination of source control and adjunct anti-infective treatment leads to favorable outcomes.

The uroS and yifB Genes Conserved among Tetrapyrrole Synthesizing-Deficient Bacteroidales Are Involved in Bacteroides fragilis Heme Assimilation and Survival in Experimental Intra-abdominal Infection and Intestinal Colonization.

The human intestinal anaerobic commensal and opportunistic pathogen Bacteroides fragilis does not synthesize the tetrapyrrole protoporphyrin IX in order to form heme that is required for growth stimulation and survival in vivo Consequently, B. fragilis acquires essential heme from host tissues during extraintestinal infection. The absence of several genes necessary for de novo heme biosynthesis is a common characteristic of many anaerobic bacteria; however, the uroS gene, encoding a uroporphyrinogen III synthase for an early step of heme biosynthesis, is conserved among the heme-requiring Bacteroidales that inhabit the mammalian gastrointestinal tract. In this study, we show that the ability of B. fragilis to utilize heme or protoporphyrin IX for growth was greatly reduced in a ΔuroS mutant. This growth defect appears to be linked to the suppression of reverse chelatase and ferrochelatase activities in the absence of uroS In addition, this ΔuroS suppressive effect was enhanced by the deletion of the yifB gene, which encodes an Mg2+-chelatase protein belonging to the ATPases associated with various cellular activities (AAA+) superfamily of proteins. Furthermore, the ΔuroS mutant and the ΔuroS ΔyifB double mutant had a severe survival defect compared to the parent strain in competitive infection assays using animal models of intra-abdominal infection and intestinal colonization. This shows that the presence of the uroS and yifB genes in B. fragilis seems to be linked to pathophysiological and nutritional competitive fitness for survival in host tissues. Genetic complementation studies and enzyme kinetics assays indicate that B. fragilis UroS is functionally different from canonical bacterial UroS proteins. Taken together, these findings show that heme assimilation and metabolism in the anaerobe B. fragilis have diverged from those of aerobic and facultative anaerobic pathogenic bacteria.

Severe sepsis caused by Parvimonas micra identified using 16S ribosomal RNA gene sequencing following patient death.

An 83-year-old man visited an orthopedic hospital for his lower back pain. A compression fracture was noted in his second lumbar vertebra. He had taken pain medication for approximately five weeks, but the pain had worsened and he was unable to walk by himself. He was transferred to our hospital and diagnosed with lumbar spondylodiscitis, an iliopsoas abscess, gas gangrene of his left lower limb, and left massive pleural effusion. He was admitted to the intensive care unit. We drained the abscess and pleural effusion, provided continuous hemodiafiltration under ventilator control, and administered intravenous antibiotics. However, he died from sepsis and multiple organ failure three days following admission. Several days after his death, gram-positive cocci were identified in blood culture, pus from the abscess, and pleural exudate; although the causative organism could not be identified. Two weeks subsequent to his death, 16S ribosomal RNA gene sequencing identified Parvimonas micra in specimens taken from his body.