Brain abscess caused by Actinomyces turicensis in a non-immunocompromised adult patient: a case report and systematic review of the literature.

BACKGROUND: Actinomyces turicensis is rarely responsible of clinically relevant infections in human. Infection is often misdiagnosed as malignancy, tuberculosis, or nocardiosis, therefore delaying the correct identification and treatment. Here we report a case of a 55-year-old immunocompetent adult with brain abscess caused by A. turicensis. A systematic review of A. turicensis infections was performed. METHODS: A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The databases MEDLINE, Embase, Web of Science, CINAHL, Clinicaltrials.gov and Canadian Agency for Drugs and Technology in Health (CADTH) were searched for all relevant literature. RESULTS: Search identified 47 eligible records, for a total of 67 patients. A. turicensis infection was most frequently reported in the anogenital area (n = 21), causing acute bacterial skin and skin structure infections (ABSSSI) including Fournier's gangrene (n = 12), pulmonary infections (n = 8), gynecological infections (n = 6), cervicofacial district infections (n = 5), intrabdominal or breast infections (n = 8), urinary tract infections (n = 3), vertebral column infections (n = 2) central nervous system infections (n = 2), endocarditis (n = 1). Infections were mostly presenting as abscesses (n = 36), with or without concomitant bacteremia (n = 7). Fever and local signs of inflammation were present in over 60% of the cases. Treatment usually involved surgical drainage followed by antibiotic therapy (n = 51). Antimicrobial treatments most frequently included amoxicillin (+clavulanate), ampicillin/sulbactam, metronidazole or cephalosporins. Eighty-nine percent of the patients underwent a full recovery. Two fatal cases were reported. CONCLUSIONS: To the best of our knowledge, we hereby present the first case of a brain abscess caused by A. turicensis and P. mirabilis. Brain involvement by A. turicensis is rare and may result from hematogenous spread or by dissemination of a contiguous infection. The infection might be difficult to diagnose and therefore treatment may be delayed. Nevertheless, the pathogen is often readily treatable. Diagnosis of actinomycosis is challenging and requires prompt microbiological identification. Surgical excision and drainage and antibiotic treatment usually allow for full recovery.

Closing the Gap in Proteomic Identification of Histoplasma capsulatum: A Case Report and Review of Literature.

Histoplasmosis is a globally distributed systemic infection caused by the dimorphic fungus Histoplasma capsulatum (H. capsulatum). This fungus can cause a wide spectrum of clinical manifestations, and the diagnosis of progressive disseminated histoplasmosis is often a challenge for clinicians. Although microscopy and culture remain the gold standard diagnostic tests for Histoplasma identification, matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) has emerged as a method of microbial identification suitable for the confirmation of dimorphic fungi. However, to our knowledge, there are no entries for H. capsulatum spectra in most commercial databases. In this review, we describe the case of disseminated histoplasmosis in a patient living with HIV admitted to our university hospital that we failed to identify by the MALDI-TOF method due to the limited reference spectrum of the instrument database. Furthermore, we highlight the utility of molecular approaches, such as conventional polymerase chain reaction (PCR) and DNA sequencing, as alternative confirmatory tests to MALDI-TOF technology for identifying H. capsulatum from positive cultures. An overview of current evidence and limitations of MALDI-TOF-based characterization of H. capsulatum is also presented.

Laboratory Automation in Microbiology: Impact on Turnaround Time of Microbiological Samples in COVID Time.

BACKGROUND: Laboratory Automation (LA) is an innovative technology that is currently available for microbiology laboratories. LA can be a game changer by revolutionizing laboratory workflows through efficiency improvement and is also effective in the organization and standardization of procedures, enabling staff requalification. It can provide an important return on investment (time spent redefining the workflow as well as direct costs of instrumentation) in the medium to long term. METHODS: Here, we present our experience with the WASPLab® system introduced in our lab during the COVID-19 pandemic. We evaluated the impact due to the system by comparing the TAT recorded on our samples before, during, and after LA introduction (from 2019 to 2021). We focused our attention on blood cultures (BCs) and biological fluid samples (BLs). RESULTS: TAT recorded over time showed a significant decrease: from 97 h to 53.5 h (Δ43.5 h) for BCs and from 73 h to 58 h (Δ20 h) for BLs. Despite the introduction of the WASPLab® system, we have not been able to reduce the number of technical personnel units dedicated to the microbiology lab, but WASPLab® has allowed us to direct some of the staff resources toward other laboratory activities, including those required by the pandemic. CONCLUSIONS: LA can significantly enhance laboratory performance and, due to the significant reduction in reporting time, can have an effective impact on clinical choices and therefore on patient outcomes. Therefore, the initial costs of LA adoption must be considered worthwhile.

Ceftazidime/Avibactam-Resistant Klebsiella pneumoniae subsp. pneumoniae Isolates in a Tertiary Italian Hospital: Identification of a New Mutation of the Carbapenemase Type 3 (KPC-3) Gene Conferring Ceftazidime/Avibactam Resistance.

Several Klebsiella pneumoniae carpabenemase (KPC) gene mutations are associated with ceftazidime/avibactam (CAZ-AVI) resistance. Here, we describe four Klebsiella pneumoniae subsp. pneumoniae CAZ-AVI-resistant clinical isolates, collected at the University Hospital of Tor Vergata, Rome, Italy, from July 2019 to February 2020. These resistant strains were characterized as KPC-3, having the transition from cytosine to thymine (CAC-TAC) at nucleotide position 814, with histidine that replaces tyrosine (H272Y). In addition, two different types of KPC gene mutations were detected. The first one, common to three strains, was the D179Y (G532T), associated with CAZ-AVI resistance. The second mutation, found only in one strain, is a new mutation of the KPC-3 gene: a transversion from thymine to adenine (CTG-CAG) at nucleotide position 553. This mutation causes a KPC variant in which glutamine replaces leucine (Q168L). None of the isolates were detected by a rapid immunochromatographic assay for detection of carbapenemase (NG Biotech, Guipry, France) and were unable to grow on a selective chromogenic medium Carba SMART (bioMerieux, Firenze, Italy). Thus, they escaped common tests used for the prompt detection of Klebsiella pneumoniae KPC-producing.

Co-infections observed in SARS-CoV-2 positive patients using a rapid diagnostic test.

Rapid diagnostic tests are tools of paramount impact both for improving patient care and in antimicrobial management programs. Particularly in the case of respiratory infections, it is of great importance to quickly confirm/exclude the involvement of pathogens, be they bacteria or viruses, while obtaining information about the presence/absence of a genetic target of resistance to modulate antibiotic therapy. In this paper, we present our experiences with the use of the Biofire® FilmArray® Pneumonia Panel Plus (FAPP; bioMérieux; Marcy l'Etoile, France) to assess coinfection in COVID-19 patients. A total of 152 respiratory samples from consecutive patients were examined, and 93 (61%) were found to be FAPP positive, with the detection of bacteria and/or viruses. The patients were 93 males and 59 females with an average age of 65 years who were admitted to our hospital due to moderate/severe acute respiratory symptoms. Among the positive samples were 52 from sputum (SPU) and 41 from bronchoalveolar lavage (BAL). The most representative species was S. aureus (most isolates were mecA positive; 30/44, 62%), followed by gram-negative pathogens such as P. aeruginosa, K. pneumoniae, and A. baumannii. Evidence of a virus was rare. Cultures performed from BAL and SPU samples gave poor results. Most of the discrepant negative cultures were those in which FAPP detected pathogens with a microbial count ≤ 105 CFU/mL. H. influenzae was one of the most common pathogens lost by the conventional method. Despite the potential limitations of FAPP, which detects a defined number of pathogens, its advantages of rapid detection combined with predictive information regarding the antimicrobial resistance of pathogens through the detection of some relevant markers of resistance could be very useful for establishing empirical targeted therapy for the treatment of patients with respiratory failure. In the COVID era, we understand the importance of using antibiotics wisely to curb the phenomenon of antibiotic resistance.

An in-depth analysis of nosocomial bloodstream infections due to Gram-negative bacilli: clinical features, microbiological characteristics and predictors of mortality in a 1 year, prospective study in a large tertiary care Italian hospital.

BACKGROUND: Bloodstream infections (BSI) due to Gram negative bacilli (GNB) represent a major concern among nosocomial infections, since they are noticeably associated with a high mortality rates, increase of healthcare costs and prolongation of hospital stay. METHODS: Over a 12-month period (2014-2015) all the adult patients admitted to a university-based Italian hospital were monitored for development of BSIs due to GNB. Multiple logistics regression models were performed to assess the impact of patients' risk factors on the in-hospital and 14-day mortality. RESULTS: During the study period 208 patients were diagnosed with at least a BSI due to a Gram negative species for an incidence rate of 12.8 cases/1,000 admissions (95%CI: 11.2-14.7). Multivariate analyses showed that multiple organ dysfunctions along with immune deficit and inadequate therapy in the first 48hrs were associated with a higher risk of death. CONCLUSIONS: A thorough evaluation of both immune status and organ dysfunction at the onset of septic events, along with adequate antimicrobial therapy appear to be the most reliable factors in predicting the outcome in these infections. SOFA score can be efficaciously substituted to the single organ dysfunctions analysis in predicting mortality after these events.

Rapid and cost-effective identification and antimicrobial susceptibility testing in patients with Gram-negative bacteremia directly from blood-culture fluid.

Rapid pathogen identification (ID) and antimicrobial susceptibility testing (AST) in bacteremia cases or sepsis could improve patient prognosis. Thus, it is important to provide timely reports, which make it possible for clinicians to set up appropriate antibiotic therapy during the early stages of bloodstream infection (BSI). This study evaluates an in-house microbiological protocol for early ID as well as AST on Gram negative bacteria directly from positive monomicrobial and polymicrobial blood cultures (BCs). A total of 102 non-duplicated positive BCs from patients with Gram-negative bacteremia were tested. Both IDs and ASTs were performed from bacterial pellets extracted directly from BCs using our protocol, which was applied through the combined use of a MALDI-TOF MS and Vitek2 automated system. The results of our study showed a 100% agreement in bacterial ID and 98.25% categorical agreement in AST when compared to those obtained by routine conventional methods. We recorded only a 0.76% minor error (mE), 0.76% major error (ME) and a 0.20% very major error (VME). Moreover, the turnaround time (TAT) regarding the final AST report was significantly shortened (ΔTAT = 8-20 h, p < 0.00001). This in-house protocol is rapid, easy to perform and cost effective and could be successfully introduced into any clinical microbiology laboratory. A final same-day report of ID and AST improves patient management, by early and appropriate antimicrobial treatment and could potentially optimize antimicrobial stewardship programs.

Emergence of KPC-producing Klebsiella pneumoniae in Italy.

BACKGROUND: The emergence of KPC-producing K. pneumoniae has now become a global concern. KPC beta-lactamases are plasmid-borne and, like extended spectrum beta lactamases (ESBLs), can accumulate and transfer resistance determinants to other classes of antibiotics. Therefore, infection control guidelines on early identification and control of the spread of organisms carrying these resistant determinants are needed. FINDINGS: Klebsiella pneumoniae carbapenemase (KPC) was detected in two isolates of carbapenem-resistant K. pneumoniae obtained from patients at an Italian teaching hospital. The first strain was isolated from a culture drawn from a central venous device (CVC) in a patient with Crohn's disease who was admitted to a gastroenterology ward. The second was isolated from a urine sample collected from an indwelling urinary catheter in an intensive care unit (ICU) patient with a subdural haematoma. The patients had not travelled abroad. Both isolates were resistant to all beta-lactams and were susceptible to imipenem and meropenem but resistant to ertapenem. Isolates also showed resistance to other classes of non-beta-lactam antibiotics, such as quinolones, aminoglycosides (with the exception for amikacin), trimethoprim-sulfamethoxazole (TMP-SMX) and nitrofurantoin. They were determined to contain the plasmid encoding the carbapenemase gene bla-KPC and were also positive in the Hodge test. CONCLUSIONS: This is the second report of KPC-producing isolates in Italy, but the first concerning KPC type 2 gene, and it may have important implications for controlling the transmission of microorganisms resistant to antibiotics.

A novel culturing system for fluid samples.

BACKGROUND: Large-volume culture methods for sterile body fluids employing automated blood-culture systems increase the recovery of microorganisms compared with traditional plate medium methods. However, in many instances a laboratory receives only small-volume samples. MATERIAL/METHODS: The URO-QUICK system (now HBandL), originally used to process urine samples, was evaluated for organism enrichment and determination of microbial count of fluid samples. Fluid specimens were also evaluated for their residual antimicrobial activity (RAA). The procedures were compared with results from a conventional culture procedure. The 546 samples included 106 endotracheal aspirate, 63 bronchoalveolar lavage, 139 sputum, 47 blood, 105 pleural fluid, 26 cerebrospinal fluids, and 41 peritoneal fluid samples as well as 19 other fluids including synovial fluid (n=5), ascitic fluid (n=9), fluids from the drainage of an infected central venous catheter (n=3), abdominal drainage fluid (n=1), and cholecystic fluid (n=1). RESULTS: The URO-QUICK system allowed the culture of an additional 44 samples (8%, p=0.007) compared with the traditional culturing method. The RAA test demonstrated good concordance with the reference method, showing specificity and positive predictive value of 100% for each, while the sensitivity and the negative predictive value were 67% and 76%, respectively. The microbial counts evaluated using the URO-QUICK system showed excellent agreement with traditional enumeration methods. CONCLUSIONS: The URO-QUICK system may well represent an excellent alternative to solid medium-based recovery and enumeration methods.