Multidrug-Resistant Proteus mirabilis Bloodstream Infections: Risk Factors and Outcomes

Abstract

Our aims were to identify (i) risk factors associated with the acquisition of multidrug-resistant (MDR, to 3 or more classes of antimicrobials) Proteus mirabilis isolates responsible for bloodstream infections (BSIs) and (ii) the impact on mortality of such infections. Risk factors for acquiring MDR P. mirabilis BSIs were investigated in a case-case-control study; those associated with mortality were assessed by comparing survivors and nonsurvivors in a cohort study. The population consisted of 99 adult inpatients with P. mirabilis BSIs identified by our laboratory over an 11-year period (1999 to 2009), 36 (33.3%) of which were caused by MDR strains, and the overall 21-day mortality rate was 30.3%. Acquisition of an MDR strain was independently associated with admission from a long-term care facility (odds ratio to which the isolate displayed in vitro resistance) more frequently than those with non-MDR infections; they also had increased mortality and (for survivors) longer post-BSI-onset hospital stays. In multivariate regression analysis, 21-day mortality was associated with septic shock at BSI onset (OR, 12.97; 95% CI, 32.2 to 52.23), P. mirabilis isolates that were MDR (OR, 6.62; 95% CI, 16.4 to 26.68), and IIAT (OR, 9.85; 95% CI, 26.7 to 36.25), the only modifiable risk factor of the 3. These findings can potentially improve clinicians' ability to identify P. mirabilis BSIs likely to be MDR, thereby reducing the risk of IIAT-a major risk factor for mortality in these cases-and facilitating the prompt implementation of appropriate infection control measures. The Gram-negative enteric bacterium Proteus mirabilis is an important cause of community-and health care-associated infections, including those involving the urinary tract, the abdominal cavity, and the bloodstream itself (13,19,50). Like many other members of the family Enterobacteriaceae, P. mirabilis can harbor numerous plasmid-and integron-mediated determinants of antimicrobial resistance (18). Multidrug-resistant (MDR) strains of P. mirabilis generally produce extended-spectrum ␤-lactamases (ESBLs) or the AmpC-type cephalosporinase and rarely carbapenemases, and their prevalence in some settings is relatively high (8,10,12,13,25,31,39,41).Over the past decade, the proportion of BSIs caused by Gramnegative bacteria has risen sharply (11,26,38,51). Although 1 to 3% of all BSIs are caused by P. mirabilis (11,26,38,51), the incidence of MDR in the strains responsible for these infections is a cause for concern. In general, MDR infections are known to have a significant impact on the prognosis and survival of hospitalized patients (9,14,24,42,43,46), but it is unclear whether MDR strains are associated with worse clinical outcomes in P. mirabilis BSIs. Endimiani et al. (13) found that treatment failure and death are likely to occur in ESBL-producing P. mirabilis BSIs. Unfortunately, this study was small, including 23 patients and only 9 patients with ESBL BSIs. However, we can reasonably assume that empirical therapy is even more likely to be inadequate...

Phenotypic detection and antibiogram of β-lactamase-producing proteus species in a tertiary care hospital, India

“…High antimicrobial resistance has also been observed in many studies. [12161718192021] Resistance to carbapenems in the present study was 12.5% which is in accordance with the studies of Datta et al . [21] and Bahashwan and Shafey;[14] however, other studies have reported a very low resistance of 0%–1%.…”

“…All P. penneri isolates were isolated from pus specimens which is similar to other studies[1119] whereas Kamga et al . in their study isolated 3%, all of which were from urine specimens.…”

Antimicrobial multiple resistance index, minimum inhibitory concentrations, and extended-spectrum beta-lactamase producers of Proteus mirabilis and Proteus vulgaris strains isolated from domestic animals with various clinical manifestations of infection

“…In humans, ESBL-producing enterobacteria are closely associated with nosocomial infections (GIGUÈRE et al, 2010). High hospital mortality was reported in 99 patients with septicemia resulting from multiple drug-resistant P. mirabilis infection; 50% of these patients were infected with ESBL-positive strains, and 30 of these individuals died from these infections (TUMBARELLO et al, 2012).…”

Emergence of Salmonella genomic island 1 (SGI1) among Proteus mirabilis clinical isolates in Dijon, France

“…P. mirabilis is a commensal enteric bacterium involved in community and health-acquired infections that can harbour many different mechanisms of antibiotic resistance. 16 To date there are five reports of SGI1-producing P. mirabilis concerning a patient from Palestine, humans and food in China and two French patients. 6,7,17 -19 In all but one case the genes contained in the MDR region are similar to those encountered in Salmonella from different serovars.…”