In vitro activity of delafloxacin against anaerobic bacteria compared with other antimicrobials.

The aim of this study was to describe the in vitro activity of delafloxacin against 230 anaerobic isolates and compare it with the activity of other antimicrobials used against infections caused by anaerobic microorganisms. Minimal inhibitory concentrations (MICs) were lower for delafloxacin than for all other antibiotics tested with the exception of piperacillin-tazobactam and meropenem against Gram-positive anaerobic cocci. Only two (0.8 %) isolates of Bacteroides spp. showed a MIC ≥4 µg/mL. With some exceptions, the present results show lower MICs for delafloxacin in comparison to the other antibiotics used against anaerobes.

Comparative evaluation of MALDI-TOF MS and 16S rRNA gene sequencing for the identification of clinically relevant anaerobic bacteria: critical evaluation of discrepant results.

OBJECTIVES: The main study objective was to evaluate the correlation between matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing results for the identification of anaerobes. METHODS: A retrospective study was conducted of all anaerobic bacteria isolated from clinically significant specimens. MALDI-TOF (Bruker Byotyper) and 16S rRNA gene sequencing were performed in all strains. Identifications were considered correct when the concordance with gene sequencing was ≥99%. RESULTS: The study included 364 isolates of anaerobic bacteria: 201 (55.2%) Gram-negative and 163 (44.8%) Gram-positive, mostly belonging to the genus Bacteroides. Isolates were largely obtained from blood cultures (128/35.4%) and intra-abdominal samples (116/32.1%). Overall, 87.3% of isolates were identified at species level using the version 9 database (89.5% of Gram-negative and 84.6% of Gram-positive anaerobic bacteria). All isolates belonging to the species B. fragilis sensu stricto were correctly identified by MALDI-TOF MS, but five cases of Phocaeicola (Bacteroides) dorei were misidentified as Phocaeicola (Bacteroides) vulgatus; all Prevotella isolates were correctly identified at the genus level, and most were correctly identified at the species level. Among Gram-positive anaerobes, 12 Anaerococcus species were not identified by MALDI-TOF MS, while six cases identified as Peptoniphilus indolicus were found to belong to other genera/species. CONCLUSIONS: MALDI-TOF is a reliable technique for identifying most anaerobic bacteria, although the database needs frequent updating to identify rare, infrequent, and newly discovered species.

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.

Do specific antimicrobial stewardship interventions have an impact on carbapenem resistance in Gram-negative bacilli? A multicentre quasi-experimental ecological study: time-trend analysis and characterization of carbapenemases.

BACKGROUND: Carbapenem-resistant Gram-negative bacilli (CR-GNB) are among the most threatening microorganisms worldwide and carbapenem use facilitates their spread. Antimicrobial stewardship programmes (ASPs) can help to optimize the use of antibiotics. This study evaluates the impact of a multifaceted educational ASP on carbapenem use and on the epidemiology of CR-GNB. METHODS: We conducted a quasi-experimental, time-series study in seven hospitals, from January 2014 to September 2018. The key intervention was composed of educational interviews promoting the appropriate use of carbapenems. The primary endpoints were carbapenem consumption and incidence density (ID) of CR-GNB. All non-duplicated CR-GNB clinical isolates were tested using phenotypic assays and PCR for the presence of carbapenemases. Joinpoint regression and interrupted time-series analyses were used to determine trends. RESULTS: A decrease in carbapenem consumption throughout the study period [average quarterly percentage change (AQPC) -1.5%, P < 0.001] and a -8.170 (-16.064 to -0.277) level change following the intervention were observed. The ID of CR-Acinetobacter baumannii decreased (AQPC -3.5%, P = 0.02) and the overall ID of CR-GNB remained stable (AQPC -0.4%, P = 0.52). CR-GNB, CR-Pseudomonas aeruginosa and CR-A. baumannii IDs per hospital correlated with the local consumption of carbapenems. The most prevalent carbapenem resistance mechanisms were OXA-23 for CR-A. baumannii (76.1%), OXA-48 for CR-Klebsiella pneumoniae (66%) and no carbapenemases for CR-P. aeruginosa (91.7%). The epidemiology of carbapenemases was heterogeneous throughout the study, especially for carbapenemase-producing Enterobacteriaceae. CONCLUSIONS: In conclusion, a multifaceted, educational interview-based ASP targeting carbapenem prescribing reduced carbapenem use and the ID of CR-A. baumannii.

First case of abdominal infection caused by bacteroides fluxus.

Bacteroides fluxus is a Gram-negative anaerobic bacillus isolated from human faeces in healthy individuals. Until now, this bacterium had not been involved in human diseases. We report the first case of abdominal infection due to this microorganism in an elderly patient. A 76-year-old man with a history of chronic pulmonary obstructive disease presented with dyspnea, orthopnea and cough. The clinical evolution worsened with both a colonic ischemia and further diffuse peritonitis of pancreatic origin. Peritoneal fluid was obtained and the culture yielded B. fluxus in pure culture. Resistance to penicillin, amoxicillin-clavulanate, clindamycin and moxifloxacin was documented. Treatment with meropenem + linezolid was started, but the patient finally died due to a multiorganic failure.

First description of abdominal infection due to Alistipes onderdonkii.

Alistipes spp is a genus of Gram-negative anaerobic rods involved in very few human diseases. We report the first case of abdominal infection due to Alistipes onderdonkii in a 58-year-old man with a history of chronic obstructive pulmonary disease. He presented with abdominal pain and general malaise after retrogastric drainage for a pancreatitis episode a few days earlier. After the diagnosis of diffuse peritonitis with perforation and necrotizing pancreatic collection, abundant pancreatic fluid was drained and yielded the isolation of A. onderdonkii in pure culture. Resistance to penicillin and moxifloxacin was documented for this strain. Treatment with metronidazole was prescribed, and the patient was discharged after improvement of his general condition.

Eggerthia catenaformis bacteremia in a patient with an odontogenic abscess.

Eggerthia catenaformis is a Gram-positive anaerobic rod, which has been rarely reported in human diseases. We report the second case of bacteremia due to this microorganism in an elderly patient. A 73-year-old man, without underlying diseases presented with fever, odynophagia and swelling of the cervical lymph node for several days. Culture of drained cervical fluid resulted in the isolation of Raoultella ornithinolytica and Streptococcus anginosus. Anaerobic blood cultures yielded a rare anaerobic microorganism, identified as Eggerthia catenaformis. No resistance to tested antimicrobials was documented. Treatment with drainage and several antibiotic regimens was established, and the general condition of the patient improved, at two months of follow-up.

Outbreaks by Klebsiella oxytoca in neonatal intensive care units: Analysis of an outbreak in a tertiary hospital and systematic review.

OBJECTIVE: Klebsiella oxytoca can cause nosocomial infections, affecting vulnerable newborns. There are few studies describing nosocomial outbreaks in the neonatal intensive care units (NICU). In this study, a systematic review of the literature was carried out to know the main characteristics of these outbreaks and the evolution of one is described. METHODS: We conducted a systematic review in the Medline database up to July 2022, and present a descriptive study of an outbreak with 21 episodes in the NICU of a tertiary hospital, between September 2021 and January 2022. RESULTS: 9 articles met the inclusion criteria. The duration of outbreaks was found to be variable, of which 4 (44.4%) lasted for a year or more. Colonization (69%) was more frequent than infections (31%) and the mortality rate was 22.4%. In studies describing sources, the most frequent was the environmental origin (57.1%). In our outbreak there were 15 colonizations and 6 infections. The infections were mild conjunctivitis without sequelae. Molecular typing analysis made it possible to detect 4 different clusters. CONCLUSIONS: There is an important variability in the evolution and results of the published outbreaks, highlighting a greater number of colonized, use of PFGE (pulsed-field gel electrophoresis) techniques for molecular typing and implementation of control measures. Finally, we describe an outbreak in which 21 neonates were affected with mild infections, resolved without sequelae and whose control measures were effective.

Nosocomial outbreak caused by Serratia marcescens in a neonatology intensive care unit in a regional hospital. Analysis and improvement proposals.

OBJECTIVES: Serratia marcescens (SM) may cause nosocomial outbreaks in Neonatal Intensive Care Units (NICU). We describe an outbreak of SM in a NICU and propose additional prevention and control recommendations. METHODS: Between March 2019 and January 2020, samples were taken from patients in the NICU (rectal, pharyngeal, axillary and other locations) and from 15 taps and their sinks. Control measures were implemented including thorough cleaning of incubators, health education to staff and neonates'relatives, and use of single-dose containers. PFGE was performed in 19 isolates from patients and in 5 environmental samples. RESULTS: From the first case in March 2019 to the detection of the outbreak, a month elapsed. Finally, 20 patients were infected and 5 colonized. 80% of infected neonates had conjunctivitis, 25% bacteremia, 15% pneumonia, 5% wound infection, and 5% urinary tract infection. Six neonates had two foci of infection. Among the 19 isolates studied, 18 presented the same pulsotype and only one of the isolates from the sinkhole showed a clonal relationship with those of the outbreak. Initial measures established were ineffective to control de outbreak and were implemented with exhaustive cleaning, use of individual eye drops, environmental sampling and changing sinks. CONCLUSION: This outbreak presented a high number of neonates affected due to its late detection and torpid evolution. The microorganisms isolated from the neonates were related to an environmental isolate. Additional prevention and control measures are proposed, including routine weekly microbiological sampling.

[Serum C-reactive protein as a marker of outcome and infection in critical care patients]. / Valor de la determinación de la proteína C reactiva como marcador pronóstico y de infección en pacientes críticos.

BACKGROUND AND OBJECTIVE: C-reactive protein (CRP) has been considered a marker for infection and an aid for diagnosing sepsis. We analyze the relation of CRP to infection and outcome in intensive care units (ICU) patients. PATIENTS AND METHOD: Prospective study on 77 ventilated patients. Expected short ICU stay or (suspected or confirmed) infection at admission were excluding criteria. 55 admissions after elective surgery were the controls. CRP measurement the first (CRP-1), third (CRP-3) and sixth (CRP-6) day of stay. APACHE II (Acute Physiology Score and Chronic Health Evaluation), SOFA (Sepsis-related Organ Failure Assessment), shock, respiratory or renal failure, leucocytes, platelets and albumin were registered. Follow-up until day 9 for infection and ICU discharge for outcome. RESULTS: CRP-1 in controls was 5.3 (3.9) mg/l and cases 67.8 (77.4) (p < 0.001). Shock on admission was related to CRP-1: patients in shock had higher CRP-1 levels (118.6 [82.8] vs 62.8 [75.6]; p = 0.06). 40.25% of cases developed infection, and CRP-1 levels were higher in this patients (88.8 [93.9] vs 53.8 [60.9]; p < 0.05). ROC area under curve was 0.6 with a sensibility of 23% and a specificity of 89% for a level of CRP-1 > 100. Mortality was 23.4% in cases and 1.8% in controls. Age, shock, APACHE II and SOFA were related to mortality, but CRP-1 did not. ROC area under curve for CRP-1 as mortality predictor in all patients was 0.62 (0.76 for APACHE II and 0.77 for SOFA) but only in cases was of 0.49 (0.69 for APACHE II and 0.67 for SOFA). CONCLUSIONS: CRP level on admission is an useful marker for early infection but not for outcome in critically ill patients admited to the ICU.

Listeria monocytogenes, a rare cause of endophthalmitis / Listeria monocytogenes, una rara causa de endoftalmitis

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Valor de la determinación de la proteína C reactiva como marcador pronóstico y de infección en pacientes críticos / Serum C-reactive protein as a marker of outcome and infection in critical care patients

Fundamento y objetivo: Analizar la utilidad de la proteína C reactiva (PCR) como marcador pronóstico y de infección en pacientes ingresados en unidades de cuidados intensivos (UCI). Pacientes y método: Se ha realizado un estudio prospectivo en 77 pacientes ventilados mecánicamente sin infección (sospechada o confirmada) en el momento del ingreso; el grupo control estuvo formado por 55 ingresos tras cirugía electiva. Determinamos el valor de PCR los días 1 (PCR-1), 4 (PCR-4) y 7 (PCR-7). Se registraron el APACHE-II (Acute Physiology Score and Chronic Health Evaluation) y SOFA (Sepsis-related Orgam Failure Assessment) al ingreso y la presencia de shock, fallo respiratorio o renal, así como la cifra de leucocitos, plaquetas y albúmina sérica durante el seguimiento (10 días para el análisis de infecciones y hasta el alta de la UCI para el del pronóstico). Resultados: El valor medio (desviación estándar) de la PCR-1 en los controles fue de 5,3 (3,9) mg/l, frente a 67,8 (77,4) mg/l en los casos (p < 0,001). Los casos con shock en el momento del ingreso presentaron valores más elevados de PCR-1 (118,6 [82,8] frente a 62,8 [75,6] mg/l, p = 0,06). El 40,25% de los casos desarrolló infección y presentó valores de PCR-1 más elevados (88,8 [93,9] comparado con 53,8 [60,9] mg/l, p < 0,05). La sensibilidad fue del 23% y la especificidad del 89% para un valor de PCR-1 superior a 100 (area bajo la curva de 0,6). Las mortalidad en los casos fue del 23,4%. La PCR-1 no se relacionó con el pronóstico en este grupo: el área bajo la curva para PCR-1 mayor de 100 como predictor de mortalidad en toda la población fue de 0,62, pero en los casos fue sólo de 0,49 (0,69 para APACHE-II y 0,67 para SOFA). Conclusiones: El valor sérico de la PCR en el momento del ingreso es un marcador temprano de infección pero no es útil como marcador pronóstico en pacientes críticos sometidos a ventilación mecánica al ingresar en la UCI