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.

New anaerobic bacteria causing infection: Bacteremia due to Murdochiellaasaccharolytica.

Murdochiella asaccharolytica is a Gram-positive anaerobic coccus firstly isolated from wound specimens, since then, it was very rarely isolated from human infections. We report the first case of bloodstream infection due to this bacterium in a 90 years-old-man. The patient had a history of B-cell lymphoma and presented with pain and induration of the base of penis along with fever. A blood culture was obtained yielding M. asaccharolytica in pure culture. Only resistance to clindamycin was demonstrated. Treatment with metronidazole was started and the clinical evolution improved with antimicrobial treatment, being discharged after 6 days.

An uncommon case of bacteremia caused by Lancefieldella parvula in an oncological patient.

We report an uncommon case of bacteremia due to Lancefieldella parvula isolated in pure culture. We present a 72 year-old-man affected with cancer admitted with abdominal pain due to a parietal rupture of the urinary bladder. After surgical treatment, the patient developed fever and two sets of blood cultures yielded a pure culture of an anaerobic microorganism identified as L. parvula (formerly Atopobium parvulum) by MALDI-TOF MS, and confirmed by 16S rRNA gene sequencing. The isolate was susceptible to all antibiotics and the outcome was finally successful. Bacteremia due to L. parvula is an uncommon disease and, in that case, MALDI-TOF MS was an useful tool for the initial identification.

Brain abscesses caused by anaerobic bacteria.

OBJECTIVES: The objective of this study was to review the characteristics, causative bacteria, treatment and outcomes of brain abscesses due to anaerobes in our health setting. METHODS: A retrospective analysis of all brain abscesses caused by anaerobic bacteria over the period 2005-2021 was performed. RESULTS: Out of 300 brain abscesses identified during the study period, 31 were produced by anaerobic pathogens, either alone (monomicrobial infection) or together with aerobic and/or anaerobic bacteria (polymicrobial infection). The mean age of the 31 patients was 53 years, and 61.2% were male; 51.6% of infections were polymicrobial, with only four (12.9%) caused by anaerobic bacteria alone. Forty-three anaerobic bacteria were isolated: Cutibacterium acnes in thirteen (41.9%), Parvimonas micra in eight (25.8%), and Prevotella spp. in seven (22.5%). The most frequent etiologies were local neurosurgery (13/41.9%) and contiguous otogenic, oral, or sinus foci of infection (8/28.8%). Cancer was present in eight patients (28.8%), headaches in seventeen (54.8%), and fever in nine (28.8%). All patients received both surgery and antimicrobial therapy. The abscess was in the frontal region in 12 patients (38.7%) and in the parietal region in 11 (35.4%). A good outcome was obtained in all patients. CONCLUSIONS: Anaerobes were isolated in 10.3% of patients with brain abscesses in our health setting, similar to other reports. C. acnes was the most frequently detected anaerobe, especially in neurosurgical patients.

The association between Fusobacterium nucleatum and cancer colorectal: A systematic review and meta-analysis.

INTRODUCTION: The etiological factors of colorectal cancer (CRC) are not precisely known, although genetic and environmental factors have been implicated. A possible association with Fusobacterium nucleatum may provide opportunities for an early diagnosis. OBJECTIVE: To review studies that address the association between F. nucleatum and CRC. METHODS: The MEDLINE PubMed database was searched using the terms «colorectal cancer¼ and "Fusobacterium nucleatum", retrieving publications published up to January 1 2020. Stata software was used for a meta-analysis. RESULTS: The systematic review included 57 articles. Meta-analysis results indicated a more frequent presence of F. nucleatum in CRC tumour tissue samples in comparison to control samples of healthy tissue, with an odds ratio of 4.558 (95% CI: 3.312-6.272), and in comparison, to control samples of colorectal adenomas, with an odds ratio of 3.244 (95 % CI: 2.359-4.462). CONCLUSION: There is a more frequent resence of F. nucleatum in the CRC. However, further studies are needed to verify this relationship.

Bacteremia caused by Anaerococcus SPP: Is this an underdiagnosed infection?

The objectives of this study were to report 10 episodes of clinically significant bacteremia caused by species of the genus Anaerococcus isolated between July 2018 and February 2021 from the microbiology laboratory of a tertiary hospital in Granada (Spain). None of the isolates were identified by MALDI-TOF MS, and the definitive species identification was performed by 16 S rRNA gene sequencing. No reference spectra of the Anaerococcus species were present in the MALDI-TOF MS database. Eight isolates were finally identified as A. octavius, one isolate as A. tetradius and the other as A. urinomassiliensis. The majority of these infections were seen in patients aged >70 years. Risk factors for anaerobic infection were observed in eight patients, especially diabetes mellitus, surgery, and the presence of cancer. Fever was present in all patients. Three patients died, but only one death was attributed to the infection. Mean detection time of positive blood cultures was 47.5 h (range 24-92 h). Antimicrobial susceptibility to penicillin, amoxicillin-clavulanate, imipenem, moxifloxacin, clindamycin, metronidazole, and piperacillin-tazobactam was tested using the gradient diffusion technique and EUCAST breakpoints (except for moxifloxacin). No resistance to amoxicillin-clavulanate, metronidazole, imipenem, or piperacillin-tazobactam was detected; however, the majority of isolates were resistant to clindamycin. When MALDI-TOF MS does not provide a correct identification at genus or species level, as in some isolates of Gram-positive anaerobic cocci, microbiologists should perform an additional confirmatory technique, such as gene sequencing analysis, to obtain a definitive diagnosis.

The association between Fusobacterium nucleatum and cancer colorectal: a systematic review and meta-analysis. / La asociación entre Fusobacterium nucleatum y el cáncer colorrectal: una revisión sistemática y metaanálisis.

INTRODUCTION: The etiological factors of colorectal cancer (CRC) are not precisely known, although genetic and environmental factors have been implicated. A possible association with Fusobacterium nucleatum may provide opportunities for an early diagnosis. OBJECTIVE: To review studies that address the association between F. nucleatum and CRC. METHODS: The MEDLINE PubMed database was searched using the terms «colorectal cancer¼ and «Fusobacterium nucleatum¼, retrieving publications published up to January 1 2020. Stata software was used for a meta-analysis. RESULTS: The systematic review included 57 articles. Meta-analysis results indicated a more frequent presence of F. nucleatum in CRC tumor tissue samples in comparison to control samples of healthy tissue, with an odds ratio of 4.558 (95% CI: 3.312-6.272), and in comparison, to control samples of colorectal adenomas, with an odds ratio of 3.244 (95% CI: 2.359-4.462). CONCLUSION: There is a more frequent presence of F. nucleatum in the CRC. However, further studies are needed to verify this relationship.

Bacteremia caused by Veillonella dispar in an oncological patient.

Veillonella dispar is a Gram-negative anaerobic coccus involved in only a few human diseases. We report the second case of bacteremia due to this microorganism in an elderly patient. A 72-year-old man with a history of bladder cancer presented with diarrhea, vomiting, and fever for 48 hours. After the diagnosis of septic shock, four sets of blood cultures were taken, and three of them yielded V. dispar. Resistance to metronidazole, penicillin, and piperacillin-tazobactam was documented. Treatment with clindamycin was started, and the patient was discharged after improvement in his general condition.

Rhodotorula dairenensis fungemia in a patient with cancer.

BACKGROUND: Rhodotorula species were traditionally considered non-virulent environmental microorganisms, but are nowadays considered important human pathogens, especially in immunocompromised individuals. CASE REPORT: We present the case of a 73 year-old man with diarrhea, anorexia and fever. In the blood analyses, both aerobic blood culture bottles yielded the growth of Rhodotorula dairenensis. The MALDI-TOF MS score was inadequate to provide an identification, which was achieved by means of molecular techniques. Treatment with an echinocandin was started, but the patient died. CONCLUSIONS: Basidiomycetous yeast genera such as Rhodotorula can cause invasive and severe infections, e.g., fungemia, especially in patients with central venous catheter or another indwelling device.

Anaerobic bacteraemia: A score predicting mortality.

The objectives of this study were to report those variables which are readily identifiable at the bedside and that are able to predict mortality in patients with bacteraemia caused by anaerobes. Patients with clinically significant anaerobic bacteraemias detected between January 2016 and December 2019 in a tertiary hospital in Granada (Spain) were retrospectively included. Species identification was performed by MALDI-TOF MS and/or molecular methods. Finally, 136 cases of anaerobic bacteraemia were included, being the most frequent anaerobes Bacteroides (45.5%; n = 62), Clostridium (24.2%, n = 33), and Gram-positive anaerobic cocci (16.1%, n = 22). Crude mortality was 25.7%, corresponding to 35 patients who died, with 82.8% of deaths directly attributable to bacteraemia. A multivariable logistic regression model with non-parametric bootstrap estimation identified three variables that were independently and significantly associated with an increased risk of death: 1) hospitalization in the intensive care unit; 2) septic shock; and 3) presence of any kind of cancer. These variables were as recorded at the time that the first positive blood culture was obtained. An index score, obtained from these variables, was calculated and divided patients into two groups with increasing likelihood of mortality resulting from anaerobic bacteraemia. The sensitivity and specificity of a prediction of death based on this model were 65.2% and 97%, respectively.

Descripción de datos clínico-epidemiológicos de pacientes pediátricos con diarrea por Aeromonas spp. y estudio de la sensibilidad antibiótica de dicho agente / Epidemiological data description of pediatric patients with diarrhea by Aeromonas spp. and the antibiotic susceptibility of this agent

Resumen El objetivo de nuestro estudio fue describir las características clínico-epidemiológicas de los pacientes pediátricos con diarrea por Aeromonas spp. y estudiar lasensibilidad antibiótica de dicho agente, a partir del análisis de casos ocurridos en un períodode 7 anos. Aeromonas caviae fue identificada en 93 muestras de heces recuperadas de ninos,el 52,2% de ellos fueron varones y el 85,6% menores de 36 meses. La estación del ano conmenor cantidad de aislamientos fue el invierno (14,4%). Hubo coinfección con otros microorganismos diarreogénicos en el 31,1% de esas muestras. El mayor número de muestras procediódel servicio de urgencias de nuestro hospital (45,6%). El 43,3% de los pacientes presentaronfiebre; el 87,8%, diarrea (43% con productos patológicos) y el 67,8%, vómitos. El 73,3% de lospacientes no precisó ingreso hospitalario. Se encontró una sensibilidad superior al 87% frentea trimetoprima-sulfametoxazol, ciprofloxacina, cefotaxima y cefepime. Todos los pacientessuperaron el proceso infeccioso aun cuando el 63,3% no recibió ningún tratamiento antibiótico.Concluimos que el tratamiento antibiótico estaría indicado en casos seleccionados, cuandoexiste gravedad clínica.© 2019 Asociacion Argentina de Microbiologıa. Publicado por Elsevier Espana, S.L.U. Este es unartıculo Open Access bajo la licencia CC BY-NC-ND (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Abstract The aim of our study was to describe the epidemiological features of pediatric patients with diarrhea caused by Aeromonas spp. and to study the antibiotic susceptibility of this agent during a seven-year period. Aeromonas caviae was identified in 93 stool samples from 52.2% males and 85.6% patients younger than 36 months. The season with the lowest number of isolates was winter (14.4%). Coinfection with other diarrheagenic microorganisms was observed in 31.1% of the cases. The largest number of isolates was obtained from Emergency Department samples (45.6%); 43.3% of the patients presented with fever, 87.8% with diarrhea (43% of these cases were associated with pathological products) and 67.8% with vomiting, while 73.3% of the patients did not require hospital admission. Susceptibility higher than 87% was observed to trimethoprim-sulfamethoxazole, ciprofloxacin, cefotaxime and cefepime. All the patients overcame the infectious process and 63.3% of them did not receive any antibiotic treat-ment during the process. A. caviae was the isolated species associated with intestinal infection. Antibiotic treatment would be specifically indicated in cases selected for their clinical severity. © 2019 Asociación Argentina de Microbiología. Published by Elsevier España, S.L.U. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/).

A rare case of bacteremia caused by Propionibacterium (Propionimicrobium) lymphophilum.

Propionibacterium (Propionimicrobium) lymphophilum is a Gram-positive anaerobic rod involved in few human diseases. We report a rare case of bacteremia due to this microorganism in an elderly patient. A 95-year-old woman without a remarkable medical history presented with dyspnea, chest pain and fever for seven days. Blood cultures resulted in isolation of P. lymphophilum. Resistance only to metronidazole was found. Treatment with amoxicillin-clavulanic acid was established, and the patient was discharged and improvement of her general condition was documented.

First description of Anaerococcus octavius as cause of bacteremia.

Anaerococcus spp. are Gram-positive anaerobic cocci involved in human skin and soft-tissue infections, among other diseases. We report the first known case of bacteremia due to A. octavius, detected in an elderly patient. A 71-year-old woman with a history of breast cancer presented with fever and cognitive impairment for more than three days. A. octavius was isolated in blood cultures, and only resistance to clindamycin was reported. Her general condition improved after treatment with metronidazole and she was discharged.

Polymicrobial anaerobic bacteremia due to Atopobium rimae and Parvimonas micra in a patient with cancer.

Atopobium rimae and Parvimonas micra are both Gram-positive anaerobes involved infrequently in human infections. We report a polymicrobial anaerobic bacteremia caused by these microorganisms. A 43-year-old woman receiving coadjuvant chemotherapy due to a retroperitoneal leiomiosarcoma presented with nausea, vomiting, abdominal pain and fever (38 °C). The two blood cultures resulted in isolation of A. rimae and P. micra, being identified at species level by matrix assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS) technology with high log scores. The microorganisms were susceptible to penicilllin, amoxicillin-clavulanate, piperacillin-tazobactam, clindamycin, metronidazole, imipenem, and moxifloxacin. Treatment with levofloxacin was started and subsequently it was changed to piperacillin/tazobactam plus metronidazole and completed for 10 days, but the patient died days later due to her underlying disease.

Infections caused by Scedosporium/Lomentospora species: Clinical and microbiological findings in 21 cases.

The clinical and microbiological characteristics of infections caused by Scedosporium/ Lomentospora species in 21 patients are described. We searched retrospectively the records for Scedosporium/ Lomentospora species seen at the University Hospital Virgen de las Nieves from 2006 to 2017. Out of them, 16 were male; mean age at diagnosis was 57.8 (±SD 15) years; all patients had risk factors for fungal infection such as corticosteroids and/or immunosuppressive treatment in 18 (85.7%) patients, pulmonary diseases in seven (33.3%) cases, hematological malignancies in six (28.5%), and organ transplantation in three (14.2%) patients. Most patients had infection in the lung/pleura (17/80.9%); cough was present in 12 patients and dyspnea in another 12, and the mean interval until diagnosis was 13.6 days. The most frequent species was S. apiospermum/S. boydii in 14 patients (66.6%), followed by L. prolificans in seven. The diagnosis was obtained from sputum in 12 (57.1%) cases, followed by pleural fluid and bronchoalveolar lavage in two of each. The most frequently used antifungals were voriconazole and amphotericin B, but combination of more than one antifungal drug was only used in three patients. Ten patients were cured, and six patients died as a consequence of the infection; three patients had chronic infection. In general, infections caused by Scedosporium/Lomentospora species are rare, serious, and difficult to diagnose and treat, having a high index or mortality especially in those caused by L. prolificans.

Infected breast cyst due to Prevotella buccae resistant to metronidazole.

Prevotella buccae is a Gram-negative anaerobic rod involved in some human infections. We report the first case of an infected breast cyst in a non-puerperal women due to this pathogen. A 53-year-old woman presented with pain and a cystic lesion in the right breast. Culture of abscess drainage resulted in isolation of P. buccae. High level of resistance to metronidazole was documented. Treatment with drainage and amoxicillin-clavulanate was established, and improvement of this infection was observed.

Two Rare Cases of Wound Infections Caused by Trueperella bernardiae.

Trueperella bernardiae (T.bernardiae) is a gram-positive curved rod that is considered an uncommon pathogen involved in few infections. The true incidence of infections with this bacterium, and the clinical implications, remain unknown. We report 2 cases of wound infections in 2 patients who underwent different surgical procedures, although in the second case the microorganism was isolated in mixed culture. Culture of wound secretions resulted in isolation of T. bernardiae. Treatment was performed and resolution of the infections was documented.

Candida Prosthetic Joint Infection. A Review of Treatment Methods.

Fungal microorganisms are still a rare cause of bone and joint infections. We report a new case of knee prosthetic joint infection due to Candida albicans in a patient with a previous two-stage right knee arthroplasty for septic arthritis due to S. epidermidis occurred several months ago. Moreover, the treatment in 76 cases of Candida prosthetic joint infection has been discussed. Forty patients were female and mean age at diagnosis was 65.7 (± SD 18) yrs. No risk factors for candidal infection were found in 25 patients. Infection site was the knee in 38 patients and hip in 36; pain was present in 44 patients and swelling in 24. The most frequent species was C. albicans, followed by C. parapsilosis. Eleven patients were only treated with antifungal drugs being the outcome favourable in all of them. Two-stage exchange arthroplasty was performed in 30 patients, and resection arthroplasty in other 30; in three patients one-stage exchange arthroplasty was done. A favourable outcome was found in 58 patients after antifungal plus surgical treatment, in 11 after antifungal treatment alone and in one after surgery alone. The type of treatment is still not clearly defined and an algorithm for treatment in fungal PJI should be established, but various types of surgical procedures may be applied.

Candida-induced prosthetic joint infection. A literature review including 72 cases and a case report.

BACKGROUND: The clinical and microbiological characteristics of prosthetic joint infection (PJI) caused by Candida species is described, including 72 cases in the literature and a case of Candida glabrata infection handled at the present centre. METHODS: We describe one patient and using the key words 'fungal prosthetic joint infection' and 'candida prosthetic joint infection' we searched MEDLINE (National Library of Medicine, Bethesda, MD), Web of Science, CINAHL and Cochrane systematic review databases for case reports of this condition. RESULTS: Out of the 73 patients, 38 were female; mean age at diagnosis was 65.7 (± SD 18) yrs; 50 had risk factors for candidal infection such as systemic disease (e.g. rheumatoid arthritis, Sjogren's syndrome, systemic lupus erythematosus) and/or immunosuppressive therapy in 18 (24.6%) cases, diabetes mellitus in 14 (19.1%), immunosuppression due to malignant or chronic disease in 24 (32.8%) and long-term antibiotic use in four (5.4%) patients. Infection site was the knee in 36 patients and hip in 35; pain was present in 43 patients and swelling in 23 and the mean surgery-diagnosis interval was 32 months. The most frequent species was C. albicans, followed by C. parapsilosis. The diagnosis was obtained from joint fluid aspirate in 33 cases and intra-operative samples in 16. Susceptibility to antifungals was tested in only 21 isolates. The most frequently used antifungals were fluconazole and amphotericin B. Two-stage exchange arthroplasty was performed in 30 patients and resection arthroplasty in 31; 56 patients were cured with a combination of medical and surgical treatment; one patient died from the infection. CONCLUSION: PJI caused by Candida requires a high index of suspicion; surgery with long-term antifungal therapy is recommended.