Proteus mirabilis Keratitis: Risk Factors, Clinical Features, Treatment Outcomes, and Microbiological Characteristics.

PURPOSE: To characterize the risk factors, clinical presentations, management choices, and outcomes of Proteus mirabilis keratitis. METHODS: In this retrospective study, 26 culture-proven cases of P. mirabilis infections were diagnosed and treated between 1998 and 2019 at the University of Pittsburgh Medical Center. Medical records were available for 14 keratitis cases and were reviewed for demographic information, ocular risk factors, and treatment outcomes. RESULTS: Sixteen eyes of 14 patients were included in the study. The average age was 47.8 ± 19.3 years, with a median follow-up time of 6 months. The most common ocular risk factors were poor ocular surface and contact lens use in 57.1% and 42.9% of cases, respectively. Eleven of the 14 patients (78.6%) had positive corneal cultures, and 13 of the 14 patients (92.9%) had positive conjunctiva or eyelid cultures. All isolates were susceptible to ciprofloxacin, ofloxacin, moxifloxacin, gatifloxacin, and cefazolin. Surgical intervention was required in 4 patients (28.6%). Average LogMAR visual acuity was 1.3 ± 1.0 at presentation and 0.9 6 ± 1.0 at the most recent follow-up visit. CONCLUSIONS: Proteus mirabilis is an uncommon cause of microbial keratitis. Patients with poor ocular surface and those who use contact lens are at increased risk for developing this cause of keratitis. Empiric treatment with fortified antibiotics or fluoroquinolones seemed to provide effective coverage for P. mirabilis.

Proteus mirabilis bloodstream infections: risk factors and treatment outcome related to the expression of extended-spectrum beta-lactamases.

Bloodstream infection (BSI) due to Proteus mirabilis strains is a relatively uncommon clinical entity, and its significance has received little attention. This study was initiated to evaluate risk factors and treatment outcome of BSI episodes due to P. mirabilis producing extended-spectrum beta-lactamases (ESBLs). Twenty-five BSI episodes caused by P. mirabilis occurred at our hospital (Ospedale di Circolo e Fondazione Macchi, Varese, Italy) over a 7.5-year period. Phenotypic and molecular methods were used to assess ESBL production. Clinical records of BSI patients were examined retrospectively. Demographic data, underlying diseases (according to McCabe and Jackson classification and Charlson weighted index), risk factors, and treatment outcome were investigated by comparing cases due to ESBL-positive strains to cases due to ESBL-negative strains. Eleven isolates were found to express ESBLs (TEM-52 or TEM-92). The remaining 14 isolates were ESBL negative and were uniformly susceptible to extended-spectrum cephalosporins and monobactams. Comparison of the two groups showed that previous hospitalization in a nursing home (P = 0.04) and use of bladder catheter (P = 0.01) were significant risk factors for infections due to ESBL-positive strains. In addition, cases due to ESBL-positive strains showed a significantly higher mortality attributable to BSI (P = 0.04). BSI cases due to ESBL-negative isolates uniformly responded to therapy, whereas 5/11 cases due to ESBL-positive isolates failed to respond (P < 0.01). Use of carbapenems was associated with complete response independently of ESBL production. Therapeutic failure and mortality may occur in BSI episodes caused by ESBL-positive P. mirabilis isolates. Thus, recognition of ESBL-positive strains appears to be critical for the clinical management of patients with systemic P. mirabilis infections.

[Bacterial pathogens, resistance patterns and treatment options in community acquired pediatric urinary tract infection]. / Bakterielle Erreger, Resistenzentwicklung und Behandlungsoptionen beim ambulant erworbenen Harnwegsinfekt im Kindesalter.

BACKGROUND: Epidemiology and resistance patterns of bacterial pathogens in pediatric UTI show large interregional variability and rates of bacterial resistances are changing due to different antibiotic treatment. We intended to evaluate data from northern Germany. PATIENTS AND METHODS: In 100 children (53 female, 47 male, mean age 4.4 +/- 4.2 years) with community acquired UTI, who presented in the emergency department of our medical school from 2000 - 2002, urine cultures were performed. Inclusion criteria were: acute voiding symptoms, significant bacteriuria with growth of at least 10 (5) colony-forming units/ml urine, leukocyturia > 50/ micro l. Exclusion criteria were underlying renal diseases, anatomic abnormalities of the urinary tract, age < 2 months and recurrent UTI. RESULTS: Patients presented with a mean rectal temperature of 38.6 +/- 1.3 degrees C, mean CRP of 66 +/- 68 mg/dl, mean WBC 13 500 +/- 5 600/ micro l and mean urinary leukocytes of 425 +/- 363/ micro l. In urine cultures E. coli was found in 47 % of the cases, Enterococcus faecalis 23 %, Proteus mirabilis 8 %, Klebsiella oxytoca 4 %, Pseudomonas aeruginosa 5 % and others 13 %. In 76 % one and in 24 % two different bacterial species (60 % Enterococcus faecalis) were cultured. Mean resistance rates were in all bacteria (in E. coli): Ampicillin 53 % (69 %), Ampicillin and Sulbactam 51 % (61 %), Cefalosporin 1 (st) generation (Cefaclor) 48 % (24 %), Cefalosporin 2 (nd) generation (Cefuroxim) 40 % (3 %), Cefalosporin 3 (rd) generation (Cefuroxim) 33 % (0 %), Tobramycin 30 % (2 %), Ciprofloxacine 0 %, Cotrimoxazole 40 % (42 %), Nitrofurantoin 12 % (0 %). CONCLUSION: The resistance rates to Ampicillin (+/- Sulbactam) did not increase as compared to previous analyses (1990 - 1995), however, resistance rates to Cotrimoxazole and 1 (st) generation Cefalosporines increased about 20 %. We conclude that the policies for treatment of UTI in children should be re-evaluated every 5 years according to local resistance rates.