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.

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.

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.

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.

Native joint septic arthritis due to Clostridium tarantellae

Clostridium is a diverse genus including more than 200 species involved in varied clinical presentations in infectious diseases. Septic arthritis caused by Clostridium sp. are however uncommon. We report here the first septic arthritis due to Clostridium tarantellae, formerly called Eubacterium tarantellae, in a patient under anti-TNF therapy.

The Occurrence of Metronidazole-Induced Encephalopathy in Cancer Patients: A Hospital-Based Retrospective Study

Background:

Metronidazole-induced encephalopathy (MIE) is a rare but serious complication caused by metronidazole, a widely used antianaerobic drug. Previous studies prescribed MIE including dysarthria, cerebellar ataxia, and confusion after long-term use of metronidazole. Malignancy has been proposed one of the predisposing conditions for MIE. However, the occurrence of MIE in cancer patients remains unknown.

Methodology:

We investigated the occurrence of MIE and analyzed retrospectively by hospital-based data of 4160 cancer patients from January 2014 to December 2016.

Results:

Findings in 793 cancer patients who underwent metronidazole therapy for anaerobic infection revealed two cases of MIE. One had renal cell carcinoma and the other had bladder urothelial carcinoma. Both of their initial presentation were cerebellar dysfunction. The occurrence of MIE was 8.6% for cases who received >30 g of cumulative dose. Hypertension was the most common comorbidity, followed by chronic renal disease and diabetes mellitus.

Conclusion:

In cancer patients, MIE should be monitored in those with genitourinary cancer, especially with renal dysfunction. Longer duration with more cumulative dose also has a greater risk of MIE. Early consideration of MIE with prompt cessation of metronidazole may result in better outcome.

Outcomes associated with Clostridium difficile infection in patients with chronic liver disease

Patients with chronic liver disease (CLD) have frequent exposure to Clostridium difficile infection (CDI) risk factors but the incidence and aetiology of CDI on this population is poorly understood. The aim of this study was to assess the incidence, disease presentation and outcomes of CDI in patients with underlying CLD. The Health Care and Utilization Project National Inpatient Sample (HCUP-NIS) 2009 dataset was used to identify patients with CLD who developed CDI along with matched non-CLD patients with CDI. Using the NIS dataset, the incidence rate of CDI was 189.4/10 000 discharges in CLD patients vs. 83.7/10 000 discharges in the non-CLD matched cohort (P < 0.001). Compared with non-CLD, comorbidity-matched controls with CDI, CLD patients with CDI had higher likelihood of in-hospital mortality (8.8% vs. 18.6%, P < 0.001), increased length of stay by 1.19 days (P < 0.001) and increased total costs by $8632 (P < 0.001). In separate analyses using a tertiary case database of hospitalised patients in Houston, Texas (2006-2016) with CLD and CDI (n = 41) compared with patients with CDI but not CLD (n = 111), CLD patients had significantly higher Charlson comorbidity index (P < 0.0001) but similar risk factors for CDI and CDI-related disease presentation compared with non-CLD patients. In conclusion, CDI-related risk factors were almost universally present in the CLD population. CDI resulted in worse outcomes in this population.

Multicentre derivation and validation of a simple predictive index for healthcare-associated Clostridium difficile infection

OBJECTIVES

Clostridium difficile infection (CDI) is the most common cause of healthcare-associated infections in the United States. Despite well-established risk factors, little research has focused on use of these variables to identify a patient population at high risk for CDI to target with primary prevention strategies. A predictive index for healthcare-associated CDI could improve clinical care and guide research for primary prevention trials. Our objective was to develop a predictive index to identify patients at high risk for healthcare-associated CDI.

METHODS

We performed a secondary database analysis in a five-hospital health system in Houston, Texas. Our cohort consisted of 97 130 hospitalized patients admitted for more than 48 hours between October 2014 and September 2016. The derivation cohort consisted of the initial 80% of admissions (75 545 patients), with the remainder being used in the validation cohort.

RESULTS

CDI rates in the derivation and validation cohorts were 1.55% and 1.43%, respectively. Thirty-day predictors of CDI were increased number of high-risk antibiotics, Charlson comorbidity index score, age and receipt of a proton pump inhibitor. These variables were incorporated into a simple risk index with a score range of 0 to 10. The final model demonstrated good discrimination and calibration with the observed CDI incidence ranging from 0.1% to 20.4%.

CONCLUSIONS

We developed a predictive index for 30-day risk of healthcare-associated CDI using readily available and clinically useful variables. This simple predictive risk index may be used to improve clinical decision making and resource allocation for CDI stewardship initiatives, and guide research design.

A case of relapsed lung abscess caused by Eubacterium brachy infection following an initial diagnosis of pulmonary actinomycosis

We report a rare case of lung abscess due to Eubacterium brachy. In this case, an analysis of the aspirate from frank pus revealed Gram-positive coccobacilli. We initially strongly suspected lung abscess associated with actinomycosis because of the chronic/recurrent clinical course and radio-pathological findings such as a granuloma lesion. Although a biochemical analysis revealed Actinomyces sp., 16S rRNA gene sequencing and a phylogenetic tree analysis of the isolated strain confirmed the presence of E. brachy. Some cases previously diagnosed as actinomycosis might be correctly diagnosed as E. brachy infection. Clinicians should be aware that additional studies using 16S rRNA gene sequencing are needed to clarify whether pulmonary infection associated with E. brachy is a similar entity to that of chronic granulomatous infection disease in pulmonary actinomycosis.

First report of metronidazole resistant, nimD-positive, Bacteroides stercoris isolated from an abdominal abscess in a 70-year-old woman

We here present the first case of a metronidazole resistant nimD positive Bacteroides stercoris. The isolate originated from a polymicrobial intra-abdominal abscess in a 70-year-old woman. The nimD gene was detected by use of whole-genome shotgun sequencing and the subsequent use of the ResFinder 2.1 web service.

Occlusive bandaging of wounds with decreased circulation promotes growth of anaerobic bacteria and necrosis: case report

Background

Topical occlusive/semi-occlusive dressings that induce a damp and trapped environment are widely used in wound treatment. Subjecting the wound with impaired circulation to such trapped/air-free environment potentiates the growth of anaerobic bacteria and risk for serious infection.

Case presentation

We present a case of previously healthy Swedish male that had a muscle contusion after heavy trauma that induced impaired circulation. The application of an occlusive bandage to the post-traumatic wound on the patient resulted in a poly-microbial anaerobic infection and necrosis. These complications were treated successfully with antibiotics and open dressing of the wound.

Conclusion

The pathophysiology of difficult- to- treat ulcers should be reviewed by the physician and occlusive dressing should be avoided when treating wounds with impaired circulation.

Delayed infection with Parvimonas micra following spinal instrumentation

BACKGROUND CONTEXT

Delayed-onset surgical site infections following spinal instrumentation are uncommon and often present with chronic pain and implant failure. Anaerobic organisms are rarely implicated and identified with difficulty in these infections.

PURPOSE

We report a case of vertebral osteomyelitis and epidural abscess due to Parvimonas micra, an anaerobic bacterium, six months following spinal instrumentation.

STUDY DESIGN/SETTING

Case Report.

RESULTS

P. micra was identified from multiple intraoperative tissue and hardware specimens. With hardware explant and antibiotic therapy, the patient had a successful outcome.

CONCLUSIONS

To our knowledge, this is the first report of a P. micra hardware-associated spinal infection.

Aspiration pneumonia: a review of modern trends

PURPOSE

The purpose was to describe aspiration pneumonia in the context of other lung infections and aspiration syndromes and to distinguish between the main scenarios commonly implied when the terms aspiration or aspiration pneumonia are used. Finally, we aim to summarize current evidence surrounding the diagnosis, microbiology, treatment, risks, and prevention of aspiration pneumonia.

MATERIALS AND METHODS

Medline was searched from inception to November 2013. All descriptive or experimental studies that added to the understanding of aspiration pneumonia were reviewed. All studies that provided insight into the clinical aspiration syndromes, historical context, diagnosis, microbiology, risk factors, prevention, and treatment were summarized within the text.

RESULTS

Despite the original teaching, aspiration pneumonia is difficult to distinguish from other pneumonia syndromes. The microbiology of pneumonia after a macroaspiration has changed over the last 60 years from an anaerobic infection to one of aerobic and nosocomial bacteria. Successful antibiotic therapy has been achieved with several antibiotics. Various risks for aspiration have been described leading to several proposed preventative measures.

CONCLUSIONS

Aspiration pneumonia is a disease with a distinct pathophysiology. In the modern era, aspiration pneumonia is rarely solely an anaerobic infection. Antibiotic treatment is largely dependent on the clinical scenario. Several measures may help prevent aspiration pneumonia.

Lemierre's syndrome: An often missed life-threatening infection

Lemierre's syndrome is an uncommon, but fatal infection of the internal jugular vein (IJV) that is usually caused by Fusobacteirum necrophorum although a wide range of bacteria has been reported as causative agents. Typical symptoms include fever, sore throat, neck swelling, pulmonary symptoms and arthralgia; however, the diagnosis of this infection is frequently overlooked as initial manifestation might be subtle and non-specific. Definite diagnosis requires positive blood culture and radiological evidence of thrombus in the IJV. We describe a case of a patient with Lemierre's syndrome who was initially misdiagnosed with viral upper respiratory tract infection. High index of suspicion is pivotal to the diagnosis of this infection and Lemierre's syndrome should always be considered as a potential cause of sepsis in an otherwise healthy patient.

Fournier's gangrene caused by Actinomyces funkei, Fusobacterium gonidiaformans and Clostridium hathewayi

We report the first case of Fournier's gangrene caused by three unusual anaerobic organisms: Actinomyces funkei, Fusobacterium gonidiaformans and Clostridium hathewayi. The infection occurred in a 73-year-old man without typical risk factors for the development of Fournier's gangrene. Clinical outcome was good after prolonged antibiotic treatment and extensive debridement of the perineum. The case suggests that A. funkei, F. gonidiaformans and C. hathewayi should be considered as potential pathogens of Fournier's gangrene. Human infections caused by these organisms are very rare but can be underestimated because correct identification is very difficult, especially in polymicrobial infections such as Fournier's gangrene.