Related Experiment Videos
Polymicrobial bacteremia: clinical and microbiologic patterns
A G Reuben1, D M Musher, R J Hamill
1Department of Medicine, Houston Veterans Administration Medical Center, Texas 77030.
Abstract:
Between 1971 and 1987, 97 patients with polymicrobial bacteremia (PMB) were seen by a consulting infectious disease service. Seventy-four had severe underlying illnesses, and infection was hospital acquired in 80. PMB resulted from intraabdominal, urinary tract, or soft tissue infection in 45 patients, but a wide range of sources were implicated in the rest. Eleven patients had more than one source for the bacteremia, and, despite intensive diagnostic efforts, 24 had no identifiable source for at least one blood isolate. Bacteremia due to gram-negative bacilli most commonly occurred in intraabdominal, urinary tract, and wound infections; Escherichia coli and Klebsiella species were most frequently isolated. Streptococcus faecalis and Staphylococcus aureus were the predominant gram-positive isolates. Certain bacterial combinations seemed to provide a clue for predicting the source of PMB: for example, S. aureus together with gram-negative facultative rods usually arose from a skin or soft tissue source, whereas S. faecalis together with a gram-negative bacillus could often be traced to an intraabdominal infection. No unique clinical features appeared to predict the occurrence of bacteremia due to multiple rather than to a single organism. The mortality in patients was 21%, lower than has previously been described in PMB but similar to that reported for bacteremia due to a single organism.
Insights
Polymicrobial bacteremia (PMB) in severe illness often originates from intraabdominal or urinary sources. Specific bacterial combinations can help predict infection origin, with a 21% mortality rate observed.
Area of Science:
- Infectious Diseases
- Clinical Microbiology
Background:
- Polymicrobial bacteremia (PMB) presents diagnostic and therapeutic challenges.
- Understanding PMB sources and outcomes is crucial for patient management.
Purpose of the Study:
- To analyze the sources, causative organisms, and outcomes of PMB.
- To identify predictors for PMB source and clinical presentation.
Main Methods:
- Retrospective review of 97 patients with PMB treated by an infectious disease service from 1971-1987.
- Analysis of patient demographics, underlying illnesses, infection sources, and microbial isolates.
- Correlation of bacterial species combinations with infection sources.
Main Results:
- Most patients (74/97) had severe underlying illnesses, and 80% of infections were hospital-acquired.
- Common sources included intraabdominal (45 patients), urinary tract, and soft tissue infections.
- Escherichia coli and Klebsiella species were frequent gram-negative isolates; Streptococcus faecalis and Staphylococcus aureus predominated gram-positive isolates.
- Specific combinations like S. aureus with gram-negative rods suggested skin/soft tissue sources, while S. faecalis with gram-negative bacilli indicated intraabdominal origins.
- Mortality was 21%, lower than previously reported for PMB.
Conclusions:
- PMB in severely ill patients frequently arises from intraabdominal and urinary sources.
- Certain bacterial combinations can aid in identifying the PMB source.
- The observed mortality rate for PMB is comparable to that of monomicrobial bacteremia.