Microbiological characteristics of bloodstream infections in a reference hospital in northeastern Brazil

Routine blood culture is used for the detection of bloodstream infections by aerobic and anaerobic bacteria and by common pathogenic yeasts. A retrospective study was conducted in a public hospital in Maceió-AL, by collecting data of all medical records with positive blood cultures. Out of the 2,107 blood cultures performed, 17% were positive with Staphylococcus coagulase negative (51.14%), followed by Staphylococcus aureus (11.21%) and Klebsiella pneumoniae (6.32%). Gram-positive bacteria predominated among positive blood cultures, highlighting the group of Staphylococcus coagulase-negative. While Gram-negative bacteria had a higher number of species among positive blood cultures.

Impact of SARS-COV-2 on the diagnosis of community bacteremia in a tertiary hospital

Objective. We carry out an analysis of the bacteremia diagnosed in the Emergency Department during 2020, coinciding with the period of the pandemic. Method. We performed a retrospective analysis from March 4, 2020 to December 31, 2020. Results. The number of patients who went to the Emergency Department during the study period and the number of extracted blood cultures decreased by 46.79% and 35.7% compared to the same period in 2019 (p <0.05). 320 bacteremia occurred while 507 occurred in 2019, assuming a decrease of 36.8% (p <0.05). The positivity rate of blood cultures was 7.09% in 2020 and 7.23% in 2019 and the contamination rate was 7.07 % in 2020 and 5.67% in 2019. The most frequently isolated microorganism was Escherichia coli, followed by Staphylococcus aureus and Klebsiella pneumoniae. A 6.62% of the isolated E. coli were carriers of extended-spectrum beta-lactamases (ESBL). The percentage of methicillin-resistant S. aureus was 12.9 % and that of K. pneumoniae ESBL was 11.54%. Conclusion. During the SARS-CoV-2 pandemic there has been a decrease in the number of bacteremia diagnoses, it is possible that attention was focused especially on COVID, forgetting other diseases, such as bacteremia.

Role of Clostridium Perfringens in Neonatal Necrotizing Enterocolitis and the Utility of Anaerobic Blood Cultures

Introduction: Clostridium perfringens is a gram-positive anaerobic bacillus that causes various clinical diseases, including necrotizing enterocolitis in newborns. The progression could be fulminant and lethal. Presentation of the cases: We report 3 cases of necrotizing enterocolitis due to C. perfringens from 2 high-complexity public centers in Chile. Conclusion: Strong clinical suspicion combined with early microbiological identification may modify patient evolution. Anaerobic blood cultures have become a fundamental diagnostic method; therefore, having this tool in neonatal units would be useful

Colistin Dependency among Colistin-Heteroresistant Acinetobacter baumannii Isolates

Colistin dependent (CD) isolates are dependent on colistin for optimal growth. Here we aimed to systematically determine the emergence of CD among colistin-heteroresistant carbapenem-resistant Acinetobacter baumannii (CRAB) isolates. We also examined the phenotypic characteristics of CD and the evolution of CD strains to overt resistance. Additionally, we examined whether detection of growth in blood cultures was impaired by CD. Heteroresistant isolates, as determined by population analysis profiling, were exposed to colistin; when the colony count with colistin was significantly higher than without, isolates were suspected to be CD. CD was confirmed by Etest and growth curves. CD strains with colistin minimum inhibitory concentrations > 2 mg/L after growth in colistin-free media were considered colistin-resistant. Of the 65 heteroresistant strains tested, eight became CD after colistin exposure. These strains attained higher colony counts and growth rates with colistin vs. without, and grew adjacent to the colistin Etest strip. CD strains exhibited increased susceptibilities to multiple antibiotics compared to their parent heteroresistant strains. All CD strains tested became colistin-resistant following growth without colistin. CD strains were detected in blood culture bottles, but time to detection was significantly prolonged compared with parent strains, suggesting that CD may lead to delay in detection of CRAB bacteremia.

Identification of Peptoniphilus harei From Blood Cultures in an Infected Aortic Aneurysm Patient: Case Report and Review Published Literature

Gram-positive anaerobic cocci (GPAC) are a commensal part of human flora but are also opportunistic pathogens. This is possibly the first study to report a case of Peptoniphilus harei bacteremia in an abdominal aortic aneurysm (AAA) patient. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) failed to identify the isolate and molecular analysis confirmed it as P. harei. A comprehensive literature review revealed that P. harei is an emergent pathogen. This study serves as a reminder for practicing clinicians to include anaerobic blood cultures as part of their blood culture procedures; this is particularly important situations with a high level of suspicion of infection factors in some noninfectious diseases, as mentioned in this publication. Clinical microbiologists should be aware that the pathogenic potential of GPAC can be greatly underestimated leading to incorrect diagnosis on using only one method for pathogen identification. Upgradation and correction of the MALDI-TOF MS databases is recommended to provide reliable and rapid identification of GPAC at species level in medical diagnostic microbiology laboratories.

Systematic Evaluation of the Accelerate Pheno System for Susceptibility Testing of Gram-Negative Bacteria Isolated from Blood Cultures

Bacteremia is a major cause of morbidity and mortality. Rapid identification of pathogens for early targeted antimicrobial therapy is crucial for detecting emergence of antibiotic resistance and improving outcomes.