First report of bacteremia caused by Eggerthia catenaformis in a patient with gastric malignancy in China

Antimicrobial Susceptibility Profile of Rare Anaerobic Bacteria

Anaerobes play an important role in clinically relevant infections and resistance is increasing worldwide. We tested 120 rare anaerobic isolates belonging to 16 genera for antimicrobial resistance using the agar dilution method and compared those results to the time-saving E-test method. The susceptibility data for 12 antimicrobial substances (benzylpenicillin, ampicillin/sulbactam, piperacillin/tazobactam, imipenem, meropenem, cefoxitin, metronidazole, moxifloxacin, clindamycin, doxycycline, tigecycline, eravacycline) were collected. Susceptibility testing showed low resistance to β-lactam/β-lactamase inhibitor combinations and no resistance to carbapenems and tigecycline. We observed moderate to high rates of resistance to moxifloxacin and clindamycin which differed depending on the methodology used. The essential and categorical agreement was over 90% for ampicillin/sulbactam, meropenem, moxifloxacin, and tigecycline. For metronidazole and clindamycin, the essential agreement was below 90% but the categorical agreement was near or above 90%. Penicillin presented with the lowest categorical agreement of 86.7% and a very high very major error rate of 13.3%. The resistance rates reported in this study are concerning and show the importance of routine susceptibility testing. Further investigations are necessary to determine the reason for high error rates and how to improve susceptibility testing of fastidious anaerobes.

Lactobacilli Infection Case Reports in the Last Three Years and Safety Implications

Lactobacilli constitute the dominant microbiota in many fermented foods and comprise widely used probiotics. However, these bacteria cause rare infections mostly in diabetic and immunocompromised subjects in presence of risk factors such as prosthetic hearth valves and dental procedures or caries. The scope of this survey was re-assessing the pathogenic potential of lactobacilli based on the infection case reports published in the last three years. In 2019, 2020, and 2021, total of 17, 15, and 16 cases, respectively, including endocarditis, bacteremia, and other infections, were reported. These annual numbers are higher than those observed previously. Lacticaseibacillus rhamnosus (13 cases), comprising strain GG (ATCC 53103) with established applications in healthcare, L. paracasei (7 cases), Lactobacillus acidophilus (5 cases), L. jensenii (5 cases), Lactiplantibacillus plantarum (3 cases), L. paraplantarum, L. delbrueckii subsp. delbrueckii, L. gasseri, L. paragasseri, Limosilactobacillus fermentum, and L. reuteri (1 case each) were involved. Virulence characterization of two strains that caused infections, a derivative of L. rhamnosus GG and L. paracasei LP10266, indicated that increased biofilm-forming capacity favors pathogenicity and it is determined by variable genetic traits. This survey highlights that the strains of lactobacilli that cause infections are little characterized genetically. Instead, to avoid that these bacteria become a hazard, genetic stability should be periodically re-evaluated by whole genome sequencing (WGS) to ensure that only non-pathogenic variants are administered to vulnerable individuals.

The first case of septic arthritis of the knee caused by Eggerthia catenaformis

Eggerthia catenaformis has been reported as a human pathogen. We present the first case of the primary knee infection caused by Eggerthia catenaformis in a 23-year-old male patient with a knee infection, after primary anterior cruciate ligament reconstruction. Eggerthia catenaformis was confirmed by MALDI-TOF mass spectrometry from synovial fluid. The dental focus was excluded. The isolated bacterial strain showed sensitivity to all of the tested antimicrobials. However, for successful management of knee infection, besides culture-directed antibiotics therapy, arthroscopic debridement and lavage were necessary.

Severe deep neck space infection caused by Eggerthia catenaformis

A 64-year-old woman was acutely referred to the Department of Otorhinolaryngology, Head and Neck Surgery, Aalborg University Hospital due to rapidly progressing neck swelling, fever and dysphagia. Clinical examination revealed submental swelling, trismus and laryngeal inflammation. A contrast-enhanced CT scan showed infection in the deep neck spaces with multiple abscesses. The patient underwent acute surgery and antimicrobial therapy was initiated and she was transferred to an intensive care unit. Three additional surgical procedures were needed before sufficient drainage was achieved. There was growth of different oral commensals from four separate pus aspirates, while Eggerthia catenaformis was cultured in all samples. Due to the extent of the infection, the patient stayed in the intensive care unit for 16 days, but recovered completely due to adequate surgery and antimicrobial therapy for 4 weeks. Here we present the third reported case of a severe deep neck space infection with multiple abscesses due to E. catenaformis.