Mirabilis Bacteremia Research Articles

Haemophilus influenzae Endophthalmitis Associated With Intravitreal Pegcetacoplan Injection

Purpose: To describe a case of endophthalmitis caused by Haemophilus influenzae, an encapsulated bacterium, after intravitreal (IVT) injection of pegcetacoplan. Methods: A single retrospective case was evaluated. Results: An 88-year-old woman with a history of diabetes mellitus, on dialysis for chronic kidney disease, hypertension, hypothyroidism, diffuse large B-cell lymphoma, and geographic atrophy in both eyes received an IVT injection of pegcetacoplan in both eyes. She subsequently developed endophthalmitis in the right eye caused by H influenzae. Further bloodwork showed Proteus mirabilis bacteremia. Conclusions: Pegcetacoplan, a complement inhibitor, may be associated with intraocular infections with encapsulated organisms, especially in immunocompromised patients.

FRI212 Adrenalitis Caused By Proteus Mirabilis In An Immunocompetent Patient

Abstract Disclosure: J.O. Abdelkarim: None. U. Tarabichi: None. M. Jakoby: None. Infectious adrenalitis with Mycobacterium tuberculosis remains the leading cause of primary adrenal insufficiency in developing countries, but the incidence of adrenalitis from infection with other bacterial species is quite low. We present a patient with radiographic evidence of adrenalitis during an infection with Proteus mirabilis that resolved after antimicrobial treatment.An 86-year-old male with an indwelling Foley catheter presented to the hospital for evaluation of abdominal pain and distension. The patient was afebrile and normotensive. Examination was notable for a distended bladder and obstructed urinary catheter. Computed tomography (CT) revealed a dense right lower lobe infiltrate and bilaterally enlarged, hypointense adrenal glands with irregular margins. Radiographic findings were new compared to a CT scan obtained approximately 10 weeks before admission to hospital. Turbid and malodorous urine was drained after replacement of the patient’s urinary catheter, and urine culture grew > 105 CFU/mL Proteus mirabilis. Antibiotics were dosed before blood cultures were drawn, and no organisms were grown from blood cultures. Since there was no clinical or biochemical evidence (e.g. hyponatremia or hyperkalemia) of primary adrenal insufficiency, an ACTH stimulation test was deferred. The patient responded well to replacement of his urinary catheter and antibiotics and was discharged to his extended care facility three days later. A CT scan obtained 10 days after treatment showed resolution of the changes to the patient’s adrenal glands observed on admission imaging.The radiographic changes are most plausibly due to P. mirabilis bacteremia and adrenalitis. The patient had urine culture confirmed infection with P. mirabilis and radiographic evidence of disseminated infection in the right lung and adrenal glands. Adrenal enlargement is well described in cases of acute M. tuberculosis adrenalitis, and radiographic changes of adrenalitis resolved after successful treatment of the patient’s infection. P. mirabilis has been documented as an etiology of Waterhouse-Friderichsen syndrome and cultured from an adrenal abscess. Blood cultures in this case were almost certainly negative due to timing relative to initial antibiotic doses. Injury to the adrenals in bacterial adrenalitis is thought to occur due to multiple mechanisms including direct infection of the glands, endotoxemia, vasculitis, and disseminated intravascular coagulation (DIC). Hemorrhage appears to occur in about 60% of cases. Elevated ACTH level is postulated as a factor predisposing to adrenal hemorrhage, and this prompted deferral of stimulation testing to evaluate adrenal function since there was no clinical evidence of primary adrenal insufficiency. Early management of the patient’s infection likely prevented the occurrence of adrenal insufficiency and deterioration of his clinical status. Presentation: Friday, June 16, 2023

Clinical Impact and Risk Factors of Nonsusceptibility to Third-Generation Cephalosporins Among Hospitalized Adults with Monomicrobial Enterobacteriaceae Bacteremia in Southern Taiwan: A Multicenter Study.

BackgroundReducing the effectiveness of broad-spectrum cephalosporins against Enterobacteriaceae infections has been recognized. This study aimed to investigate risk factors and clinical significance of third-generation cephalosporin nonsusceptibility (3GC-NS) among the cases of monomicrobial Enterobacteriaceae bacteremia (mEB) at regional or district hospitals.MethodsThe study was conducted at three hospitals in southern Taiwan between Jan. 2017 and Oct. 2019. Only the first episode of mEB from each adult (aged ≥20 years) was included. The primary outcome was in-hospital crude mortality.ResultsOverall there were 499 episodes of adults with mEB included, and their mean age was 74.5 years. Female predominated, accounting for 53% of all patients. Escherichia coli (62%) and Klebsiella pneumoniae (21%) were two major causative species. The overall mortality rate was 15% (73/499), and patients infected by 3GC-NS isolates (34%, 172/499) had a higher mortality rate than those by 3GC-susceptible isolates (66%, 327/499) (21% vs 11%, P=0.005). By the multivariate analysis, 3GC-NS was the only independent prognostic determinant (adjusted odds ratio [AOR], 1.78; P=0.04). Of note, male (AOR 2.02, P=0.001), nosocomial-acquired bacteremia (AOR 2.77, P<0.001), and usage of nasogastric tube (AOR 2.01, P=0.002) were positively associated with 3GC-NS, but P. mirabilis bacteremia (AOR 0.28, P=0.01) and age (AOR 0.98, P=0.04) negatively with 3GC-NS.ConclusionFor adults with Enterobacteriaceae bacteremia, 3GC-NS signifies a significant prognostic impact. Efforts to rapid identification of such antimicrobial resistance profiles should be incorporated into antimicrobial stewardship programs to achieve favorable outcomes.

Definitive Cefazolin Therapy for Stabilized Adults with Community-Onset Escherichia coli, Klebsiella Species, and Proteus mirabilis Bacteremia: MIC Matters.

Background: Cefazolin is in vitro active against wild isolates of Escherichia coli, Klebsiella species, and Proteus mirabilis (EKP), but clinical evidence supporting the contemporary susceptibility breakpoint issued by the Clinical and Laboratory Standards Institute (CLSI) are limited. Methods: Between 2010 and 2015, adults with monomicrobial community-onset EKP bacteremia with definitive cefazolin treatment (DCT) at two hospitals were analyzed. Cefazolin minimum inhibitory concentrations (MICs) were correlated with clinical outcomes, including primary (treatment failure of DCT) and secondary (30-day mortality after bacteremia onset, recurrent bacteremia, and mortality within 90 days after the end of DCT) outcomes. Results: Overall, 466 bacteremic episodes, including 340 (76.2%) episodes due to E. coli, 90 (20.2%) Klebsiella species, and 16 (3.6%) P. mirabilis isolates, were analyzed. The mean age of these patients was 67.8 years and female-predominated (68.4%). A crude 15- and 30-day mortality rate was 0.7% and 2.2%, respectively, and 11.2% experienced treatment failure of DCT. A significant linear-by-linear association of cefazolin MICs, with the rate of treatment failure, 30-day crude mortality, recurrent bacteremia or 90-day mortality after the DCT was present (all γ = 1.00, p = 0.01). After adjustment, the significant impact of cefazolin MIC breakpoint on treatment failure and 30-day crude mortality was most evident in 2 mg/L (>2 mg/L vs. ≤2 mg/L; adjusted hazard ratio, 3.69 and 4.79; p < 0.001 and 0.02, respectively). Conclusion: For stabilized patients with community-onset EKP bacteremia after appropriate empirical antimicrobial therapy, cefazolin might be recommended as a definitive therapy for cefazolin-susceptible EKP bacteremia, based on the contemporary CLSI breakpoint.

Primary and Secondary Bacteremia Caused by Proteus spp.: Epidemiology, Strains Susceptibility and Biofilm Formation.

Proteus spp. is an etiological factor of urinary tract and bloodstream infections. The aim of this study was the retrospective analysis of susceptibility of Proteus spp. strains isolated from bloodstream infections (BSIs) as well as similarity evaluation of the strains isolated from different clinical samples. Proteus spp. strains were isolated in 2009–2017 from hospital patients. Identification was based on the colony’s morphology and biochemical or MALDI-TOF MS analyzes. The antibiotic susceptibility test was done using the diffusion method. Biofilm formation was evaluated with microplate method using TTC. Bacteremia caused by Proteus spp. was found in 97 patients, mainly secondary to urinary tract infection. Most of the strains were susceptible to piperacillin with tazobactam (95.9%) and amikacin (86.7%). Elderly patients have a higher risk of mortality after BSIs caused by Proteus spp. A detailed analysis was made for randomly chosen 26 strains isolated from 11 patients with Proteus mirabilis bacteremia. Using PFGE, we found that 10 (90.9%) isolates, collected from different clinical specimens of the same patient, were genetically identical.

Clinical benefits of antimicrobial de-escalation in adults with community-onset monomicrobial Escherichia coli, Klebsiella species and Proteus mirabilis bacteremia

The clinical benefits of an antimicrobial de-escalation strategy were compared with those of a no-switch strategy in bacteremic patients. Adults with community-onset monomicrobial Escherichia coli, Klebsiella species and Proteus mirabilis bacteremia treated empirically using broad-spectrum beta-lactams, including third-generation cephalosporins (GCs), fourth-GC or carbapenems, were treated definitively with first- or second-GCs (de-escalation group), the same regimens as empirical antibiotics (no-switch group), or antibiotics with a broader-spectrum than empirical antibiotics (escalation group). The eligible 454 adults were categorized as the de-escalation (231 patients, 50.9%), no-switch (177, 39.0%), and escalation (46, 10.1%) groups. Patients with de-escalation therapy were more often female, had less critical illness and fatal comorbidity, and had a higher survival rate than patients in the other two groups. After propensity score matching in the de-escalation and no-switch groups, critical illness at onset (Pitt bacteremia score ≥ 4; 16.5% vs. 12.7%; P = 0.34) or day 3 (2.5% vs. 2.5%; P = 1.00), fatal comorbidity (16.5% vs. 21.5%; P = 0.25), time to defervescence (4.6 vs. 4.7 days; P = 0.89), hospital stays (11.5 vs. 10.3 days; P = 0.13) and 4-week crude mortality rate (4.4% vs. 4.4%; P = 1.00) were similar. However, lower antibiotic cost (mean: 212.1 vs. 395.6 US$, P < 0.001) and fewer complications of bloodstream infections due to resistant pathogens (0% vs. 5.1%, P = 0.004) were observed in the de-escalation group. De-escalation to narrower-spectrum cephalosporins is safe and cost-effective for adults with community-onset EKP bacteremia stabilized by empirical broad-spectrum beta-lactams.

Propensity-matched analysis of the impact of extended-spectrum β-lactamase production on adults with community-onset Escherichia coli, Klebsiella species, and Proteus mirabilis bacteremia.

The presence of extended-spectrum β-lactamase (ESBL) in Escherichia coli, Klebsiella species, and Proteus mirabilis (EKP) is of great microbiological and clinical importance. The study dealing with the direct impact of ESBL producers on the outcome of patients with community-onset bacteremia is lacking. Adults with community-onset EKP bacteremia were recruited retrospectively during a 6-year period. ESBL producers were determined according to ESBL phenotype. ESBL patients were compared on a 1:2 basis with non-ESBL patients by using propensity-score matching (PSM) calculated based on independent predictors of 28-day mortality. Of the 1141 eligible adult patients, 65 (5.7%) caused by ESBL producers. Significant differences between the two groups were discovered in the proportions of patients with critical illness (a Pitt bacteremia score≥4) at bacteremia onset, inappropriate empirical antibiotic therapy, bacteremia because of urosepsis and pneumonia, and several comorbidities. In a PSM analysis after controlling for six independent predictors-critical illness at bacteremia onset, underlying fatal comorbidities (McCabe classification), inappropriate empirical antibiotic therapy, comorbidities with liver cirrhosis, bacteremia because of urosepsis and pneumonia-a appropriate matching between two groups (ESBL group, 60 patients; non-ESBL group, 120) were observed in age, causative microorganism, bacteremia severity, major comorbidities, comorbidity severity, and major bacteremia source. Consequently, a strong relationship between ESBL producers and poor prognosis was highlighted. The adverse influence of ESBL producers on clinical outcomes was presented with respect to adults with community-onset EKP bacteremia. Establishing a predictive scoring algorithm for identifying patients at risk of ESBL-producer infections is crucial.

The impact of production of extended-spectrum \u03b2-lactamases on the 28-day mortality rate of patients with Proteus mirabilis bacteremia in Korea

BackgroundThe incidence of Proteus mirabilis antimicrobial resistance, especially that mediated by extended-spectrum β-lactamases (ESBLs), has increased. We investigated the impact of ESBL production on the mortality of patients with P. mirabilis bacteremia in Korea.MethodsPatients diagnosed with P. mirabilis bacteremia between November 2005 and December 2013 at a 2000-bed tertiary care center in South Korea were included in this study. Phenotypic and molecular analyses were performed to assess ESBL expression. Characteristics and treatment outcomes were investigated among ESBL-producing and non-ESBL-producing P. mirabilis bacteremia groups. A multivariate analysis of 28-day mortality rates was performed to evaluate the independent impact of ESBLs.ResultsAmong 62 P. mirabilis isolates from 62 patients, 14 expressed ESBLs (CTX-M, 2; TEM, 5; both, 6; other, 1), and the 28-day mortality rate of the 62 patients was 17.74%. No clinical factor was significantly associated with ESBL production. The 28-day mortality rate in the ESBL-producing group was significantly higher than that in the non-ESBL-producing group (50% vs. 8.3%, p = 0.001). A multivariate analysis showed that ESBL production (odds ratio [OR], 11.53, 95% confidence interval [CI], 2.11–63.05, p = 0.005) was independently associated with the 28-day mortality rate in patients with P. mirabilis bacteremia.ConclusionsESBL production is significantly associated with mortality in patients with bacteremia caused by P. mirabilis. Rapid detection of ESBL expression and prompt appropriate antimicrobial therapy are required to reduce mortality caused by P. mirabilis bacteremia.

An Unusual Cause of Infective Endocarditis: Proteus mirabilis Bacteremia from an Infected Pressure Ulcer

Proteus species is a common cause of urinary tract and wound infections in humans. We herein present the case of a 71-year-old male who had fever, a new-onset heart murmur, bacteremia, and a vegetation over his native aortic valve in echocardiography. This rare case demonstrated that infective endocarditis could be caused by Proteus mirabilis from an infected pressure ulcer.

Carbapenems and piperacillin/tazobactam for the treatment of bacteremia caused by extended-spectrum β-lactamase–producing Proteus mirabilis

This study was intended to delineate the role of carbapenems and piperacillin/tazobactam in treating bacteremia caused by extended-spectrum β-lactamase (ESBL)–producing Proteus mirabilis. We performed a multicenter and retrospective study of the patients with ESBL-producing P. mirabilis bacteremia. The outcomes of the patients treated by piperacillin/tazobactam or a carbapenem for at least 48 hours and the MICs of the prescribed drugs for these isolates were analyzed. Forty-seven patients with available clinical data were included. The overall 30-day mortality rate was 29.8%. All available isolates (n = 44) were susceptible to ertapenem, meropenem, and doripenem, and 95.6% were susceptible to piperacillin/tazobactam; however, only 11.4% of the isolates were susceptible to imipenem. Among the 3 patients infected with isolates exhibiting non-susceptibility to imipenem (MIC ≥2 mg/L) who were treated with imipenem, none died within 28 days. The 30-day (14.3% versus 23.1%, P = 0.65) or in-hospital (19.1% versus 30.8%, P = 0.68) mortality rate of 21 patients treated by a carbapenem was lower than that of 13 treated by piperacillin/tazobactam. However, among those treated by piperacillin/tazobactam, the mortality rate of those infected by the isolates with lower piperacillin/tazobactam MICs (≤0.5/4 mg/L) was lower than that of the isolates with MICs of ≥1/4 mg/L (0%, 0/7 versus 60%, 3/5; P = 0.045). ESBL-producing P. mirabilis bacteremia is associated with significant mortality, and carbapenem therapy could be regarded as the drugs of choice. The role of piperacillin/tazobactam, especially for the infections due to the isolates with an MIC ≤0.5/4 mg/L, warrants more clinical studies.

Characteristics of bacteremia caused by extended-spectrum beta-lactamase-producing Proteus mirabilis

Although Proteus mirabilis is a common human pathogen, bacteremia caused by the organism, especially strains producing extended-spectrum beta-lactamase (ESBL), has rarely been investigated. We examined 64 cases of P. mirabilis bacteremia identified in the Minami Ibaraki Area, Japan, between 2001 and 2010 and compared the characteristics of cases with ESBL-producing and ESBL-non-producing strains (13 and 51 cases, respectively). All ESBL-producing strains with the gene encoding the CTX-M-2-group were genetically nonidentical. Isolation of ESBL-producing strains was significantly associated with onset in a hospital (p=0.030), receiving hemodialysis (p=0.0050), and previous antibiotic use within 1month (p=0.036; especially penicillin and/or cephalosporin (p=0.010) and fluoroquinolone (p=0.0069)). Isolation was also associated with inappropriate antibiotic therapy on the 1st and 4th days (p=0.011 and 0.032, respectively) but not with mortality on the 30th day. These findings indicate that, for P. mirabilis bacteremia, isolation of ESBL-producing strains causes delay of initiating appropriate antimicrobial therapy but may not be associated with mortality.

Proteus mirabilis urinary tract infection and bacteremia: Risk factors, clinical presentation, and outcomes

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. 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. 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. 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.

Epidemiology of Ciprofloxacin Resistance and Its Relationship to Extended-Spectrum β-Lactamase Production inProteus mirabilisBacteremia

Background/AimsWe evaluated the clinical features of ciprofloxacin-resistant Proteus mirabilis bacteremia and risk factors for ciprofloxacin resistance.MethodsFrom October 2000 to July 2009, 37 patients with clinically significant P. mirabilis bacteremia were identified and data from patients with ciprofloxacin-resistant and ciprofloxacin-susceptible P. mirabilis bacteremia were compared.ResultsThe most common underlying diseases were neurologic disease (37.8%) and solid tumors (29.7%). The most common site of infection was the urinary tract (35.1%). Ten of the 37 patients (27.0%) were infected with ciprofloxacin-resistant isolates, and univariate analysis revealed a significant relationship between ciprofloxacin-resistant P. mirabilis bacteremia and neurologic disease, recent operation, L-tube insertion, percutaneous tube use, and extended-spectrum β-lactamase (ESBL) production (all p < 0.05). ESBL was detected in six of 10 (60%) ciprofloxacin-resistant isolates, while only three of 27 (11%) ciprofloxacin-susceptible isolates produced ESBL (p = 0.005). In a logistic regression analysis, ESBL production remained a significant factor associated with ciprofloxacin resistance, after adjusting for other variables.ConclusionsThese data indicate a close association between ciprofloxacin resistance and ESBL-production in P. mirabilis bacteremia. This association is particularly troublesome because the therapeutic options for serious infections caused by ESBL-producing P. mirabilis are severely restricted.

Orbital cellulitis and endogenous endophthalmitis secondary to Proteus mirabilis cholecystitis

We report the first case of orbital cellulitis and endogenous endophthalmitis secondary to Proteus mirabilis bacteremia that resulted from a calculus cholecystitis. Despite resolution of the gallbladder infection with antimicrobial therapy, the patient required evisceration of the affected eye. The pathogenesis of hematogenous endophthalmitis due to Gram-negative bacilli is discussed.

Proteus mirabilis Bacteremia: A Review of 176 Cases During 1980–1992

Patients with Proteus mirabilis bacteremia at a large community teaching hospital during a 13-year period (1980-1992) were retrospectively reviewed. There were 176 patients whereof 44 (25%) had polymicrobial bacteremia. The median age of patients was 75 years and 64.2% were 70 years or older. Of the patients 56.8% came from a nursing home, 64.2% had an indwelling Foley catheter, and 20.5% nosocomial bacteremia. The most common source of bacteremia was the urinary tract (52.8%) whereas the lower respiratory tract was an uncommon source. Hypotension was present in 30.1% of patients. The overall mortality rate was 29.0% with an attributable mortality rate of 25.6%. The mortality rate of polymicrobial bacteremia (38.6%) was higher than that of monomicrobial bacteremia (25.8%). For patients with monomicrobial bacteremia, significant increase in mortality was found in patients who had nosocomial infection (p < 0.02), whose source of bacteremia was other than the urinary tract (p < 0.01), who had ultimately fatal underlying conditions (p < 0.01), who had hypotension (p < 0.001), who had increase in serum creatinine (p < 0.05), or who had increase in serum bilirubin (p < 0.05).

Phialophora gougerotii: an opportunistic fungus in a patient treated with steroids.

A 53 year old Negro male with rheumatoid arthritis received various steroid compounds intermittently for 9 years and continuously for 5 years. After an intramuscular injection in the right buttock, he developed subcutaneous abscesses and sinus tracts at the site of inoculation. Incision and drainage were performed twice, 4 years later. After an exacerbation of the abscesses, microscopic examination of the purulent material revealed hyphal elements. Culture of this material yielded Phialophora gougerotii in pure culture. Total excision of the infected area was performed and skin grafts were successfully applied. The patient died 3 months post-operatively from Proteus mirabilis bacteremia. At autopsy there was no evidence of fungal dissemination. This case is presented as a report of P. gougerotii causing infection secondary to 5 years continuous steroid therapy for rheumatoid arthritis.