Unresolved issues in the epidemiology and diagnosis of bacteremia: an opinion paper.

Bacteremia is an important cause of morbidity and mortality worldwide and, despite the diagnostic and therapeutic advances of the last decades, the evidence supporting many diagnostic aspects of bacteremia is scarce. Information on the epidemiological evolution of this entity is limited and many methodological aspects of blood culture collection and analysis are under discussion. Furthermore, the recommendations of the main scientific societies on many of these aspects are variable and, in many cases, have not been updated recently. In this scenario, we have arranged a series of questions on different aspects of bacteremia and reviewed the literature trying to find proper answers for them. We offer our opinion on the topics where the evidence was weak. The topics covered include epidemiological aspects of bacteremia, indications for blood culture extraction, methods for obtaining and incubating samples, or ways of transmitting results from the microbiology laboratory. We do not intend to summarize the current clinical practice guidelines, nor will we deal with the therapeutic management of this entity. The aim of this paper is to review the current perspective on the diagnosis of bacteremia with a critical approach, to point out the gaps in the literature, to offer the opinion of a team dedicated to infectious diseases and clinical microbiology, and to identify some areas of knowledge on which future studies should focus.

Prevalence of Multidrug-Resistant Pathogens Causing Bloodstream Infections in an Intensive Care Unit.

Introduction: Bloodstream infections are the most severe infections that cause the highest mortality rate, especially in patients admitted to the intensive care unit (ICU). In this study, we aimed to analyze the distribution, resistance patterns and prevalence of MDR (multidrug-resistant) pathogens isolated in blood samples collected from patients with severe invasive infections hospitalized in the ICU. Methods: A retrospective study of bacterial pathogens was performed on 490 patients admitted to the ICU between 2017 and 2020. The resistance patterns were analyzed using Vitek 2 Compact system. Results: In total, 617 bacterial isolates were obtained. Four hundred and twenty-seven isolates (69.21%) were Gram positive and 190 isolates (30.79%) were Gram negative bacteria. The most frequently isolated micro-organisms identified in the blood samples for the entire period (2017-2020) were Coagulase-negative staphylococci (CoNS) (318-51.54%), followed by Klebsiella pneumoniae (70-11.34%), Methicillin-Resistant Staphylococcus aureus (MRSA) (58-9.40%), Acinetobacter baumannii (45-7.29%) and Enterococcus faecalis (42-6.80%). The number of Klebsiella pneumoniae strains significantly increased in 2020, compared to the previous year (p < 0.05). The Acinetobacter baumannii prevalence was significantly higher in the age group of 20-64 years (10.89%) and over 65 years (3.53%) (p < 0.001). The difference between the prevalence of CoNS in the elderly (67.84%) and in adults (20-64 years) (52.47%) was also statistically significant (p < 0.001). High rates of MDR were found for Acinetobacter baumannii (97.77%), Pseudomonas aeruginosa (65%), Klebsiella pneumoniae (50%), Enterococcus faecalis (47.61%) and MRSA (46.55%). More than 60% of the Klebsiella pneumoniae strains were found to be resistant to carbapenems. Conclusion: The study revealed an alarming prevalence of MDR strains isolated in blood samples of the patients admitted to the ICU, indicating the necessity of consistent application of the measures to control.

MDR BACTERIAL INFECTIONS IN CRITICALLY ILL COVID-19 PATIENTS IN A TERTIARY CARE HOSPITAL (OF PAKISTAN)

Objective: To identify antimicrobial susceptibility pattern of multidrug resistant bacteria causing secondary infections in COVID-19 patients in ICU's of a tertiary care hospital. Study Design: Cross-sectional study. Place and Duration of Study: Department of Microbiology, Pak Emirates Military Hospital, Rawalpindi, from Apr to Jul 2020. Methodology: This study included blood samples and endotracheal aspirates from 114 critically ill COVID-19 patients. Peripheral blood specimens were collected from the patients with secondary bacterial blood stream infections and endotracheal aspirates were collected from patients with ventilator associated pneumonia for culture and sensitivity. The results were interpreted according to Clinical and Laboratory Standard Institute (CLSI) 2020. Results: A total of 114 COVID-19 patients were admitted in ICU during that time period. Fourteen (12.28%) were female and 100 (87.71%) were male, age distribution was between 36-82 years. Sixty six paired blood samples were sent to the microbiology lab out of which 51 (77.2%) showed bacterial growth while 15 (22.7%) samples were negative. Out of 50 endotracheal aspirates, 42 showed bacterial growth (84%) and 8 samples did not show any significant bacterial growth (16%). Most of the endotracheal aspirates showed growth of >1 bacterial isolates. The most common gram-negative organisms were Acinetobacter baumannii (n=54) and Klebsiella Pneumoniae (n=26) and most common gram-positive organism isolated was Enterococcus faecium (n=9). All isolated organisms were multidrug resistant. Conclusion: Poor antimicrobial stewardship particularly in critical care units resulted in secondary bacterial infections in COVID-19 patients. The pathogens isolated were multidrug resistant including Acinetobacter baumannii, Klebsiella Pneumoniae and Enterococcus faecium.

Beating the Bio-Terror Threat with Rapid Antimicrobial Susceptibility Testing.

A bioterror event using an infectious bacterium may lead to catastrophic outcomes involving morbidity and mortality as well as social and psychological stress. Moreover, a bioterror event using an antibiotic resistance engineered bacterial agent may raise additional concerns. Thus, preparedness is essential to preclude and control the dissemination of the bacterial agent as well as to appropriately and promptly treat potentially exposed individuals or patients. Rates of morbidity, death, and social anxiety can be drastically reduced if the rapid delivery of antimicrobial agents for post-exposure prophylaxis and treatment is initiated as soon as possible. Availability of rapid antibiotic susceptibility tests that may provide key recommendations to targeted antibiotic treatment is mandatory, yet, such tests are only at the development stage. In this review, we describe the recently published rapid antibiotic susceptibility tests implemented on bioterror bacterial agents and discuss their assimilation in clinical and environmental samples.