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Proteus mirabilis urinary tract infection and bacteremia: risk factors, clinical presentation, and outcomes
Chi-Yu Chen1, Yen-Hsu Chen, Po-Liang Lu
1Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. infectionman@gmail.com
Background/Purpose:
Proteus mirabilis is a common pathogen responsible for complicated urinary tract infections (UTIs) that sometimes causes bacteremia. Most cases of P. mirabilis bacteremia originate from a UTI; however, the risk factors for bacteremia and mortality rates from P. mirabilis UTI have not been determined.
Methods:
A retrospective, case-control study was performed between May 2008 and November 2010 to identify the risk factors and markers for P. mirabilis bacteremic UTI. Each subject in the case group (all patients were diagnosed with P. mirabilis bacteremia from a urinary tract source) was matched by age and gender to two subjects in the control group (patients diagnosed with P. mirabilis UTI but with negative blood culture results). Clinical presentation and laboratory data were analyzed to determine the risk factors and markers of P. mirabilis bacteremic UTI.
Results:
Sixty-seven bacteremic UTIs and 124 nonbacteremic UTIs were included in this study. Community-acquired infection (p=0.017), hydronephrosis (p=0.017), band neutrophils accounting for >10% of the white blood cell count (p=0.001), hyperthermia or hypothermia (p=0.047), and a serum C-reactive protein concentration >100mg/L (p=0.002) were identified as independent risk factors for P. mirabilis bacteremic UTI. Seventeen patients died in hospital, including 11 in the bacteremic group and 6 in the nonbacteremic group. The bacteremic group had a higher mortality rate (p=0.016). Bacteremic UTI (p=0.049), shock (p=0.014), and a low body mass index (BMI) <18 kg/m(2) (p=0.033) were identified as independent risk factors for mortality.
Conclusion:
Because bacteremic P. mirabilis UTIs are associated with higher mortality, clinicians should carefully manage cases that present with the risk factors for bacteremia, including community-acquired infection, hydronephrosis, band neutrophils accounting for >10% of the white blood cell count, hyperthermia or hypothermia, and a high level of C-reactive protein.
Insights
Proteus mirabilis urinary tract infections (UTIs) with bacteremia have higher mortality. Risk factors for bacteremia include community-acquired infection and hydronephrosis. Early identification and management of these risk factors are crucial.
Area of Science:
- Urology
- Infectious Diseases
- Clinical Microbiology
Background:
- Proteus mirabilis is a frequent cause of complicated urinary tract infections (UTIs).
- Bacteremia can arise from UTIs, but risk factors and mortality for P. mirabilis bacteremia remain unclear.
Purpose of the Study:
- To identify risk factors and markers associated with P. mirabilis bacteremic UTI.
- To determine factors influencing mortality in patients with P. mirabilis UTI.
Main Methods:
- Retrospective case-control study (May 2008-November 2010).
- Matched cases (P. mirabilis bacteremic UTI) with controls (P. mirabilis UTI, negative blood cultures).
- Analyzed clinical presentation and laboratory data.
Main Results:
- Community-acquired infection, hydronephrosis, elevated band neutrophils (>10%), hyper/hypothermia, and high C-reactive protein (>100mg/L) were risk factors for bacteremic UTI.
- Bacteremic UTI was associated with higher mortality.
- Shock and low BMI (<18 kg/m²) were independent risk factors for mortality.
Conclusions:
- Bacteremic P. mirabilis UTIs carry a higher mortality risk.
- Clinicians should monitor patients with risk factors like community-acquired infection, hydronephrosis, specific neutrophil counts, temperature dysregulation, and elevated CRP.
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