Dimitra Dimopoulou

Aerosolized plus Intravenous Colistin versus Intravenous Colistin Alone for the Treatment of Ventilator-Associated Pneumonia: A Matched Case-Control Study

OBJECTIVES The incidence of ventilator-associated pneumonia (VAP) due to multidrug-resistant (MDR) organisms is increasing. Intravenous (IV) colistin or aerosolized (AS) plus IV colistin have been recently used to treat these life-threatening infections. The purpose of this study was to compare the efficacy and safety of AS plus IV colistin versus IV colistin alone for patients with MDR VAP due to gram-negative bacteria. METHODS A retrospective matched case-control study was performed at the Intensive Care Unit of the University Hospital of Heraklion, Greece, from January 2005 through December 2008. Forty-three patients with VAP due gram-negative MDR pathogens received AS plus IV colistin and were matched on the basis of age and Acute Physiology and Chronic Health Evaluation II score with 43 control patients who had received IV colistin alone. RESULTS Demographic characteristics, clinical status, and gram-negative isolated pathogens were similar between the 2 treatment groups. Acinetobacter baumannii (66 cases [77%]) was the most common pathogen, followed by Klebsiella pneumoniae (12 cases [14%]) and Pseudomonas aeruginosa (8 cases [9.3%]). No colistin-resistant strains were isolated from patients in either group. No significant differences between the 2 groups were observed regarding eradication of pathogens (P = .679), clinical cure (P = .10), and mortality (P = .289). Eight patients (19%) in each treatment group developed reversible renal dysfunction. No AS colistin-related adverse events were recorded. CONCLUSIONS Addition of AS colistin to IV colistin did not provide additional therapeutic benefit to patients with MDR VAP due to gram-negative bacteria.

Stenotrophomonas maltophilia infections in a general hospital: patient characteristics, antimicrobial susceptibility, and treatment outcome.

Introduction Stenotrophomonas maltophilia is acquiring increasing importance as a nosocomial pathogen. Methods We retrospectively studied the characteristics and outcome of patients with any type of S. maltophilia infection at the University Hospital of Heraklion, Crete, Greece, between 1/2005–12/2010. S. maltophilia antimicrobial susceptibility was tested with the agar dilution method. Prognostic factors for all-cause in-hospital mortality were assessed with multivariate logistic regression. Results Sixty-eight patients (median age: 70.5 years; 64.7% males) with S. maltophilia infection, not related to cystic fibrosis, were included. The 68 patients were hospitalized in medical (29.4%), surgical (26.5%), hematology/oncology departments (23.5%), or the intensive care units (ICU; 20.6%). The most frequent infection types were respiratory tract (54.4%), bloodstream (16.2%), skin/soft tissue (10.3%), and intra-abdominal (8.8%) infection. The S. maltophilia-associated infection was polymicrobial in 33.8% of the cases. In vitro susceptibility was higher to colistin (91.2%), trimethoprim/sulfamethoxazole and netilmicin (85.3% each), and ciprofloxacin (82.4%). The empirical and the targeted treatment regimens were microbiologically appropriate for 47.3% and 63.6% of the 55 patients with data available, respectively. Most patients received targeted therapy with a combination of agents other than trimethoprim/sulfamethoxazole. The crude mortality and the mortality and the S. maltophilia infection-related mortality were 14.7% and 4.4%, respectively. ICU hospitalization was the only independent prognostic factor for mortality. Conclusion S. maltophilia infection in a general hospital can be associated with a good prognosis, except for the patients hospitalized in the ICU. Combination reigmens with fluoroquinolones, colistin, or tigecycline could be alternative treatment options to trimethoprim/sulfamethoxazole.

Risk factors for carbapenem-resistant Klebsiella pneumoniae infection/colonization: A case–case-control study

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is increasingly reported worldwide. The aim of the present study was to identify risk factors associated with the development of CRKP infections. A retrospective, case-case-control study was performed at the University Hospital of Heraklion, Greece. The study population included 83 patients from whom CRKP was isolated, 79 from whom carbapenem-sensitive K. pneumoniae (CSKP) was isolated and 161 (control group) from whom K. pneumoniae was not isolated. The median age of CRKP and CSKP patients was 79 (28-101) and 80 (39-97) years, respectively, while that of the controls was 75 (18-100) years. K. pneumoniae was isolated predominantly from urine in both case groups, followed by blood. Independent risk factors for CRKP infection/colonization were admission to ICU (p = 0.004), prior surgical procedure (p = 0.036) and presence of renal disease (p = 0.037), while for CSKP were neurological disease (p = 0.007), and older age (p = 0.011). No association between CRKP and prior antimicrobial exposure was found. Of the entire cohort 40 patients (12%) died; 22 (27%) in the CRKP, 12 (15%) in the CSKP and 6 (4%) in the control group. Isolation of any K. pneumoniae strain was associated with higher mortality compared to the control group (21% vs. 4%; p < 0.005). Mortality was not statistically different between those infected/colonized/with a CRKP or a CSKP strain (p = 0.084). According to these results prior ICU stay, prior surgical procedure and renal disease were independent risk factors for the development of a CRKP infection/colonization.

Trends of isolation of intrinsically resistant to colistin Enterobacteriaceae and association with colistin use in a tertiary hospital.

The objective of this investigation was to evaluate the association between colistin consumption and the isolation of intrinsically resistant to colistin Enterobacteriaceae (IRCE) in a university hospital in Crete, Greece. The database of the microbiological laboratory was reviewed retrospectively during 2006–2010. All positive cultures for IRCE were retrieved. We assessed the total consumption of colistin in medical, surgical, and intensive care units (ICUs). A total of 1,304 single-patient IRCE isolates were recorded. Of these, 466 (35.7%) were hospital-acquired, while 838 (64.3%) were community-acquired. Proteus spp. accounted for 72% of them, Serratia spp. for 16.6%, Morganella morganii for 8.4%, and Providencia spp. for 3%. Urine (44.8%), pus (20.4%), and lower respiratory tract specimens (12.8%) accounted for the majority of specimens. IRCE isolated during the first half (2006 to 1st semester of 2008) and second half (2nd semester of 2008 to 2010) of the study period accounted for 5.8% and 7.4% of Gram-negative isolates, respectively (p < 0.001). Colistin consumption was not different in the two periods in the hospital, but in the ICU, it was higher in the second half of the study period (p = 0.013). Colistin consumption was associated with the isolation of hospital-acquired IRCE (p = 0.037); a trend was noted between colistin consumption and the isolation of IRCE in the ICU (p = 0.057). In this study, colistin consumption was associated with the isolation of hospital-acquired IRCE. The use of colistin increased in the ICU during the study period. Prudent use of colistin is essential for the prevention of nosocomial outbreaks due to resistant IRCE.

Effects of carbapenems and their combination with amikacin on murine gut colonisation by Candida albicans

Carbapenems are broad‐spectrum antibiotics increasingly used for the treatment of severe infections. We evaluated the effects of four carbapenems given as monotherapies or in combination with amikacin on the level of gastrointestinal colonisation by Candida albicans in a previously established mouse model. Adult male Crl : CD1 (ICR) BR mice were fed chow containing C. albicans or regular chow. The mice fed with Candida chow had their gut colonised by the yeast. Both groups were subsequently given imipenem, meropenem, ertapenem, doripenem or their combination with amikacin or normal saline subcutaneously for 10 days. Stool cultures were performed immediately before, at the end and 1 week after discontinuation of treatment. Candida‐colonised mice treated with the antibiotics had higher counts of the yeast in their stools than control C. albicans‐colonised animals treated with saline. All four carbapenems and their combination with amikacin caused a significant increase in C. albicans concentration. Mice fed regular chow and treated with the study antibiotics or saline did not have any Candida in their stools. Dissemination of Candida was not detected in any animal. These data suggest that carbapenems and carbapenem plus amikacin induce substantial increases in the murine intestinal concentration of C. albicans.

Skin and soft tissue infections in patients with solid tumours.

Background. Skin and soft tissue infections (SSTIs) in cancer patients represent a diagnostic challenge, as etiologic diagnosis is often missing, and clinical assessment of severity is difficult. Few studies have described (SSTIs) in patients with solid tumours (STs). Patients and Methods. Records of patients with ST and SSTI, cared for at the University Hospital of Heraklion, from 2002 to 2006 were retrospectively studied. Results. A total of 81 episodes of SSTIs, occurring in 71 patients with ST, have been evaluated. Their median age was 65 years (34–82). The most common underlying malignancy was breast cancer in 17 patients (24%). Most episodes (89%) occurred in nonneutropenics. Cellulitis/erysipelas was the most common clinical presentation (56; 69%). Bacterial cultures were possible in 29 (36%) patients. All patients received antimicrobial therapy, while in 17 episodes (21%) an incision and drainage was required. Treatment failure occurred in 20 episodes (25%). Five patients (7%) died due to sepsis. None was neutropenic. Severe sepsis on admission (P = 0.002) and prior blood transfusion (P = 0.043) were independent predictors of treatment failure. Conclusion. SSTIs can be life threatening among patients with ST. Early diagnosis and appropriate treatment are of the utmost importance, since sepsis was proven a significant factor of unfavourable outcome.

Study on the comparative activity of echinocandins on murine gut colonization by Candida albicans

Colonization of the gastrointestinal (GI) tract by Candida species is a principal pathogenetic event for development of invasive candidiasis. Importantly, the effect of echinocandins, the preferred antifungal agents for treatment of invasive candidiasis, on GI tract colonization by Candida spp. is currently unknown. Herein, we used an established model of persistent murine GI tract colonization by Candida albicans to test the ability of different echinocandins to eradicate the yeast from murine gut. Adult male Crl:CD1 (ICR) BR mice were fed with chow containing C. albicans and subsequently treated with different echinocandins or normal saline via daily intraperitoneal injections for 10 days. Quantitative stool cultures were performed immediately before (week one), and weekly for three months after discontinuation of treatment. Notably, treatment with all three echinocandins used (caspofungin, anidulafungin, and micafungin) resulted in eradication of Candida albicans from the stools, as evidenced by the significant reduction of yeast cells from a mean of 4.2 log10 CFU/g of stool before treatment (week one of colonization) to undetectable (<2 log10 CFU/g of stool) levels (week 12, P < 0.0001). In contrast, there was no significant reduction of Candida yeast cells in the stools of control mice. Collectively, the ability of echinocandins to eradicate C. albicans from the stools could have important implications in prophylaxis of high-risk patients for development of invasive candidiasis originating from the GI tract.

Anidulafungin versus Caspofungin in a Mouse Model of Candidiasis Caused by Anidulafungin-Susceptible Candida parapsilosis Isolates with Different Degrees of Caspofungin Susceptibility

ABSTRACT Candida parapsilosis isolates occasionally display resistance in vitro to echinocandins and cause breakthrough infections to echinocandins. The degree of the in vivo cross-resistance among echinocandins and the fitness loss associated with caspofungin (CAS) resistance of C. parapsilosis are not well studied. We compared the activities of CAS and anidulafungin (ANF), each given at 2 dosing schedules (high dose or low dose) in a nonneutropenic mouse model of invasive candidiasis (IC) caused by ANF-susceptible isolates of C. parapsilosis with different degrees of susceptibility to CAS (CAS resistant [CAS-R], MIC, >16 mg/liter; CAS intermediate [CAS-I], MIC, 4 mg/liter; and CAS susceptible [CAS-S], MIC, 2 mg/liter). We analyzed tissue fungal burden, histopathology, and weight loss patterns. Increasing CAS resistance was associated with reduced virulence of C. parapsilosis isolates (mortality rates for CAS-S versus CAS-I versus CAS-R, 100% versus 11.1% versus 0%, respectively; P < 0.001). High doses of either echinocandin were active against infection with the CAS-I isolate when assessed by fungal burden reduction and weight gain. In contrast to CAS-S and CAS-I isolates, there was no reduction in fungal burden in mice infected with the CAS-R isolate following treatment with either echinocandin, each given at a high or low dose. Nevertheless, mice infected with the CAS-R isolate had reduced disease severity following echinocandin treatment, suggesting that echinocandins have activity in vivo, even against echinocandin-resistant strains. A complex interplay of residual echinocandin activity, decreased virulence, and/or fitness of isolates with altered cell wall and possible immunomodulatory effects can be encountered in vivo during infection with CAS-resistant C. parapsilosis isolates.

Susceptibility of Glycopeptide-Resistant Enterococci to Linezolid, Quinupristin/dalfopristin, Tigecycline and Daptomycin in a Tertiary Greek Hospital.

We investigated the antibiotic susceptibility of glycopeptide-resistant enterococci (GRE). Seventy consecutive GRE were tested. Sixty-two isolates were identified as Enterococcus faecium (88.6%), and 8 (11.4%) as Enterococcus faecalis. All strains were susceptible to linezolid and daptomycin, while 17.1% (12/70) and 11.4% (8/70) were resistant to quinupristin/dalfopristin (QD) and tigecycline, respectively. All E. faecalis isolates were resistant to QD, while 4 of 62 (6.5%) E. faecium isolates were resistant to QD. All E. faecalis isolates were susceptible to tigecycline, while 14.5% (9/62) E. faecium isolates were resistant. Continued surveillance of GRE antibiotic susceptibilities is important for combating these multi-resistant nosocomial pathogens.

Delayed-Onset Mycobacterium tuberculosis Prosthetic Joint Infection after Hip Hemiarthroplasty: A Case Report and Review of the Literature

Prosthetic joint infection (PJI) due to Mycobacterium tuberculosis (MTB) without previous history of tuberculosis is an extremely rare complication. We report the case of an 80-year-old man, with no prior history of tuberculosis. The patient underwent replacement arthroplasty and the infection was successfully treated with combination of oral anti-tuberculous drugs for one year.