Cristina Pitart

Candida species bloodstream infection: epidemiology and outcome in a single institution from 1991 to 2008.

Candidaemia remains a major cause of morbidity and mortality in the healthcare setting. Candida spp. bloodstream infection episodes prospectively recorded through a blood culture surveillance programme in a single institution from 1991 to 2008 were included in the study. Data regarding candidaemia episodes were analysed, including specific fungal species and patient survival at 30 days after diagnosis. There were 529 candidaemia episodes during the study period (495 were nosocomial infections). The incidence of candidaemia caused by non-Candida albicans Candida spp. (52%) was higher than the incidence of candidaemia caused by C. albicans (48%). The overall crude 30 day mortality rate was 32%. Patients with Candida parapsilosis candidaemia had the lowest mortality rate (23%). Candida krusei candidaemia was most commonly associated with haematological malignancy (61%; P < 0.001), stem cell transplantation (22%; P = 0.004), neutropenia (57%; P = 0.001) and prior use of antifungal azole agents (26%; P < 0.001). Patients with C. krusei candidaemia had the highest crude 30 day mortality in this series (39%). Epidemiological studies are important to define clinical and microbiological candidaemia characteristics and to guide empirical treatment in every setting.

First Outbreak of a Plasmid-Mediated Carbapenem-Hydrolyzing OXA-48 β-Lactamase in Klebsiella pneumoniae in Spain

ABSTRACT Twenty Klebsiella pneumoniae isolates producing OXA-48 were collected from April 2009 to September 2010. Strains were clonally related and coproduced a CTX-M-15 β-lactamase. A conjugative plasmid of circa 70 kb carrying blaOXA-48 was identified. Eleven isolates showed low-level resistance to carbapenems, whereas nine showed high-level resistance. Decreased expression of OmpK36 was related to high-level resistance to carbapenems. The isolates belonged to sequence type 101 (ST101). This is the first outbreak caused by an OXA-48-producing K. pneumoniae strain in Spain.

First Description of an Escherichia coli Strain Producing NDM-1 Carbapenemase in Spain

ABSTRACT A carbapenem-resistant Escherichia coli strain (DVR22) was recovered from a stool specimen from a patient with travelers diarrhea who had traveled to India. Molecular screening led to the first identification of NDM-1 in Spain. The blaNDM-1 gene was located in a conjugative plasmid of ca. 300 kb that also contained the blaCTX-M-15, blaTEM-1, ΔblaDHA-1, and armA genes. In addition, blaNDM-1 was preceded by an ISAba125 insertion element only found in Acinetobacter spp.

Influence of Empiric Therapy with a β-Lactam Alone or Combined with an Aminoglycoside on Prognosis of Bacteremia Due to Gram-Negative Microorganisms

ABSTRACT Evidence supporting the combination of aminoglycosides with β-lactams for Gram-negative bacteremia is inconclusive. We have explored the influence on survival of empirical therapy with a β-lactam alone versus that with a β-lactam-aminoglycoside combination by retrospectively analyzing a series of bacteremic episodes due to aerobic or facultative Gram-negative microorganisms treated with single or combination therapy. The outcome variable was a 30-day mortality. Prognostic factors were selected by regression logistic analysis. A total of 4,863 episodes were assessed, of which 678 (14%) received combination therapy and 467 (10%) were fatal. Factors independently associated with mortality included age greater than 65 (odds ratio [OR], 2; 95% confidence interval [CI], 1.6 to 2.6), hospital acquisition (OR, 1.5; 95% CI, 1.2 to 1.9), a rapidly or ultimately fatal underlying disease (OR, 2.5; 95% CI, 2 to 3.2), cirrhosis (OR, 1.9; 95% CI, 1.4 to 2.6), prior corticosteroids (OR, 1.5; 95% CI, 1.1 to 2), shock on presentation (OR, 8.8; 95% CI, 7 to 11), pneumonia (OR, 2.8; 95% CI, 1.9 to 4), and inappropriate empirical therapy (OR, 1.8; 95% CI, 1.3 to 2.5). Subgroup analysis revealed that combination therapy was an independent protective factor in episodes presenting shock (OR, 0.6; 95% CI, 0.4 to 0.9) or neutropenia (OR, 0.5; 95% CI, 0.3 to 0.9). Combination therapy improved the appropriateness of empirical therapy in episodes due to extended-spectrum β-lactamase (ESBL)- or AmpC-producing Enterobacteriaceae and Pseudomonas aeruginosa. In patients with Gram-negative bacteremia, we could not find an overall association between empirical β-lactam-aminoglycoside combination therapy and prognosis. However, a survival advantage cannot be discarded for episodes presenting shock or neutropenia, hence in these situations the use of combination therapy may still be justified. Combination therapy also should be considered for patients at risk of being infected with resistant organisms, if only to increase the appropriateness of empirical therapy.

Evolution of antimicrobial resistance in enteroaggregative Escherichia coli and enterotoxigenic Escherichia coli causing traveller's diarrhoea

OBJECTIVES Enteroaggregative Escherichia coli (EAEC) and enterotoxigenic E. coli (ETEC) are among the most frequent microorganisms causing travellers diarrhoea. The aim of this study was to investigate the evolution of antimicrobial resistance in EAEC and ETEC causing diarrhoea in patients who had travelled to different developing countries, comparing two periods of time, 1994-97 and 2001-04. METHODS Overall, 134 EAEC and 190 ETEC clinical isolates were studied. The MICs of ampicillin, chloramphenicol, nalidixic acid, tetracycline, trimethoprim/sulfamethoxazole, ciprofloxacin and amoxicillin/clavulanic acid were determined by the Etest method. Detection of mutations in the quinolone-resistance determining region of the gyrA and parC genes was performed by PCR and DNA sequencing. RESULTS When antimicrobial resistance in EAEC and ETEC isolates was compared between the two periods of time, a statistically significant increase in resistance (P < 0.01) was observed in EAEC for chloramphenicol and amoxicillin/clavulanic acid, whereas in ETEC it was for trimethoprim/sulfamethoxazole, nalidixic acid, ciprofloxacin and amoxicillin/clavulanic acid. Mutations in the gyrA gene were found in all nalidixic acid-resistant isolates, whereas mutation(s) in both gyrA and parC genes were found in the ciprofloxacin-resistant isolates. CONCLUSIONS The high percentage of resistance to quinolones in ETEC and EAEC isolated from travellers to North Africa and India is a matter for concern. These agents should therefore be used with caution in patients with travellers diarrhoea returning from these geographical areas.

A comparative study of two different methods of sample preparation for positive blood cultures for the rapid identification of bacteria using MALDI-TOF MS

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has lately been implemented as a solid technology for rapid microorganism identification in microbiology laboratories. This study compares two methods for bacterial separation from 85 positive blood culture before MALDI-TOF MS: (1) a conventional method that we used in our laboratory to prepare bacteria for susceptibility testing and (2) a new commercialized technique (Sepsityper). There were no significant differences in the identification of Gram-negative bacilli regardless of the bacterial separation method used. However, identification was greater for Gram-positive cocci when the Sepsityper method was used (84.15% vs. 100% in the identification to a genus level in staphylococci and 57.14% vs. 85.71% in the identification to a genus level of enterococci with the in-house and Sepsityper methods, respectively). Therefore, the Sepsityper method to prepare bacteria from a positive blood culture is more adequate for the further identification of Gram-positive cocci by MALDI-TOF MS.

Candida spp. bloodstream infection: influence of antifungal treatment on outcome

OBJECTIVES To assess the influence of new antifungal treatments on candidaemia outcome. METHODS Candidaemia episodes prospectively collected through a blood culture surveillance programme in a single institution. The study was divided into two periods of time, 1994-2003 (A) and 2004-2008 (B), according to the introduction of echinocandin treatment. Non-conditional logistic regression methods with mortality as the dependent variable were used. RESULTS Four hundred and thirty-three (3%) candidaemias out of 15 628 bloodstream infection episodes were analysed. Candida albicans was the most frequent species (211; 49%). Mortality was noted in 132 cases (30%). A total of 262 and 171 candidaemias were reported in period A and B, respectively. There were 94 deaths in period A (36%) and 38 in period B (22%, P = 0.03). Treatment in period A was amphotericin B in 89 patients (41 dead, 46%) and fluconazole in 151 (41 dead, 27%, P = 0.003). In period B, 113 patients received a triazole (26 dead, 23%), 30 an echinocandin (3 dead, 10%, P = 0.08) and 9 (0 dead) were treated with combined therapy (echinocandin and triazole). Mortality was higher in period A (94 dead, 36%) than in period B (38 dead, 27%), P = 0.03. Independent risk factors associated with mortality in period B were: age, chronic renal failure, ultimately or rapidly fatal prognosis of underlying disease and shock. Echinocandin alone or in combination therapy was associated with better outcome (odds ratio = 0.22, 95% confidence interval = 0.06-0.81, P = 0.02). CONCLUSIONS In patients with candidaemia, echinocandin therapy results in a better outcome.

Epidemiology and prognostic determinants of bacteraemic catheter-acquired urinary tract infection in a single institution from 1991 to 2010

OBJECTIVES To determine the epidemiology of bacteraemic Catheter-Acquired Urinary Tract Infection (CA-UTI) and to identify independent predictors of mortality. METHODS This study was part of a bloodstream infection surveillance study that prospectively collected data on consecutive patients with bacteraemia in our institution from 1991 to 2010. Factors associated with 30-day mortality were determined. RESULTS CA-UTI was the confirmed source of 1007 bacteraemias. The most common microorganisms isolated were Escherichiacoli (42%), Klebsiella spp (15%), Enterococcus faecalis (12%) and Pseudomonas aeruginosa (12%). Along the 2006-2010 periods, antibiotic-resistant E. coli and Klebsiella spp isolates accounted for 49% of the bacteraemia due to CA-UTI. Shock and mortality accounted for 125 and 92 cases, respectively (12% and 9%). Factors associated with mortality were: inappropriate empirical treatment (OR: 1.86, 95% CI: 1.48-2.44), ultimately or rapidly fatal prognosis of underlying disease (OR: 2.56, 95% CI: 1.48-4.44) and shock on presentation (OR: 12.62, 95% CI: 7.61-20.95). Inappropriate empirical treatment was most frequent in cases of bacteraemia produced by antibiotic-resistant E. coli or Klebsiella spp, Enterococcus spp. and P. aeruginosa. Factors associated with the isolation of a microorganism of this type were previous antibiotic therapy and healthcare-associated bacteraemia (OR: 1.50, 95% CI: 1.16-2.14 and OR: 3.03, 95% CI: 2.22-4.01, respectively). CONCLUSIONS In cases of previous antibiotic therapy or healthcare-associated bacteraemic CA-UTI may indicate the need to initiate empirical therapy activity against antibiotic-resistant Enterobacteriaceae, E. faecalis and P. aeruginosa.

Epidemiology and prognostic determinants of bacteraemic biliary tract infection

OBJECTIVES To determine the epidemiology of bacteraemia due to biliary tract infection (BTI) and to identify independent predictors of mortality. METHODS This study was part of a bloodstream infection surveillance study that prospectively collected data on consecutive patients with bacteraemia in our institution from 1991 to 2010. BTI was the confirmed source of 1373 patients with bacteraemia, and the independent prognostic factors of 30 day mortality were determined. RESULTS The mean age of patients with biliary sepsis was 71 years (± 14 years). The most frequent comorbidities were biliary lithiasis and solid-organ cancer [484 cases (35%) and 362 cases (26%), respectively]. The BTI was healthcare-associated in 33% of patients. Shock and mortality accounted for 209 and 126 cases, respectively (15% and 9%). The most frequent microorganisms isolated were Escherichia coli (749, 55%), Klebsiella spp. (240, 17%), Enterococcus spp. (171, 12%), Pseudomonas aeruginosa (86, 6%) and Enterobacter spp. (63, 5%). There were 47 (3%) cefotaxime-resistant (CTX-R) E. coli or Klebsiella spp. Inappropriate empirical antibiotic treatment was an independent factor associated with mortality (OR 1.4, 95% CI 1.1-1.7). Inappropriate empirical treatment was more frequent in P. aeruginosa and CTX-R Enterobacteriaceae bacteraemia. These microorganisms were significantly more common in patients with previous antibiotic therapy, solid-organ cancer or transplantation and in healthcare-associated bacteraemia. CONCLUSIONS In patients with bacteraemic BTI, inappropriate empirical therapy was more frequent in P. aeruginosa and CTX-R Enterobacteriaceae infection and was associated with a higher mortality rate. In patients with bacteraemia due to BTI and solid-organ cancer or transplantation, healthcare-associated infection or previous antibiotic treatment, initial therapy with piperacillin/tazobactam or a carbapenem would be advisable.

Molecular Characterization of blaNDM-5 Carried on an IncFII Plasmid in an Escherichia coli Isolate from a Nontraveler Patient in Spain

ABSTRACT A carbapenem-resistant Escherichia coli isolate (sequence type 448 [ST448]) was recovered from a urine culture of a female patient with no recent record of traveling. PCR screening identified the presence of blaNDM-5, blaTEM-1, blaOXA-1, blaCMY-42, and rmtB. blaNDM-5 was carried in a conjugative IncFII-type plasmid (90 kb) together with blaTEM-1 and rmtB. The genetic environment of blaNDM-5 showed a structure similar to those of pMC-NDM and pGUE-NDM, identified in Poland and France in E. coli of African and Indian origin, respectively.