Burden of antimicrobial resistance in European hospitals: excess mortality and length of hospital stay associated with bloodstream infections due to Escherichia coli resistant to third-generation cephalosporins.

OBJECTIVES: This study determined excess mortality and length of hospital stay (LOS) attributable to bloodstream infection (BSI) caused by third-generation-cephalosporin-resistant Escherichia coli in Europe. METHODS: A prospective parallel matched cohort design was used. Cohort I consisted of patients with third-generation-cephalosporin-resistant E. coli BSI (REC) and cohort II consisted of patients with third-generation-cephalosporin-susceptible E. coli BSI (SEC). Patients in both cohorts were matched for LOS before infection with patients free of the respective BSI. Thirteen European tertiary care centres participated between July 2007 and June 2008. RESULTS: Cohort I consisted of 111 REC patients and 204 controls and cohort II consisted of 1110 SEC patients and 2084 controls. REC patients had a higher mortality at 30 days (adjusted odds ratio = 4.6) and a higher hospital mortality (adjusted hazard ratio = 5.7) than their controls. LOS was increased by 8 days. For SEC patients, these figures were adjusted odds ratio = 1.9, adjusted hazard ratio = 2.0 and excess LOS = 3 days. A 2.5 times [95% confidence interval (95% CI) 0.9-6.8] increase in all-cause mortality at 30 days and a 2.9 times (95% CI 1.2-6.9) increase in mortality during entire hospital stay as well as an excess LOS of 5 days (95% CI 0.4-10.2) could be attributed to resistance to third-generation cephalosporins in E. coli BSI. CONCLUSIONS: Morbidity and mortality attributable to third-generation-cephalosporin-resistant E. coli BSI is significant. If prevailing resistance trends continue, high societal and economic costs can be expected. Better management of infections caused by resistant E. coli is becoming essential.

Carbapenem-resistant versus carbapenem-susceptible Acinetobacter baumannii bacteremia in a Greek intensive care unit: risk factors, clinical features and outcomes.

BACKGROUND: There has been an increasing incidence of carbapenem-resistant Acinetobacter baumannii (CRAB) infections in recent years. The objective of this study was to determine specific risk factors for and outcome of bacteremia due to CRAB isolates among our ICU patients with A. baumannii bacteremia. PATIENTS AND METHODS: Among 96 patients with ICU-acquired A. baumannii bacteremia, 30 patients with CRAB were compared with the remaining 66 with carbapenem-susceptible A. baumannii (CSAB) isolates. RESULTS: Recent ventilator-associated pneumonia (VAP) due to CRAB (OR 16.74, 95% CI 3.16-88.79, p = 0.001) and a greater number of intravascular devices (OR 3.93, 95% CI 1.9-13.0, p = 0.025) were independently associated with CRAB bacteremia acquisition. Patients with CRAB bacteremia had a lower severity of illness on admission than those with CSAB. Although, by univariate analysis, patients with CRAB were more likely to have had exposure to colistin, carbapenems and linezolid, multivariate analysis did not revealed any significant association. The mortality was not different between patients with CRAB and CSAB bacteremia (43.3 vs. 46.9%, p = 0.740). Severity of organ failure (OR 1.42, 95% CI 1.20-1.67, p = 0.001), and increased white blood cell (WBC) count (OR 1.09, 95% CI 1.01-1.19, p = 0.036), at bacteremia onset were independently associated with mortality. CONCLUSION: VAP due to CRAB and excess use of intravascular devices are the most important risk factors for CRAB bacteremia in our ICU. Severity of organ failure and WBC count at A. baumannii bacteremia onset are independently associated with mortality.

Prospective monitoring of BK virus replication in renal transplant recipients.

BACKGROUND: BK virus-associated nephropathy (BKVAN) can be diagnosed only with renal graft biopsy. Definitive diagnosis of BKVAN requires demonstration of BK virus (BKV) replication in renal allograft tissues. Non-invasive analysis of urine and blood is considered essential in screening renal transplant recipients. PATIENTS AND METHODS: This study evaluated prospectively the replication of BKV in plasma and urine with qualitative and quantitative real-time polymerase chain reaction in 32 de novo (group A) and 34 chronic (group B) renal transplant recipients and the long-term impact on graft function. RESULTS: In group A, 456 samples (228 plasma, 228 urine) were examined and BKV was detected in 31 (31/228, 14%) samples of plasma and 57 (57/228, 25%) samples of urine in 20 (20/32, 62.5%) and 23 (23/32, 72%) recipients, respectively. Incidence of viremia and viruria increased during the first 6 months presenting a peak the third postoperative month (viremia: 28% and viruria: 31%). Immune suppressive treatment with tacrolimus showed significant relation with viremia. Renal graft function in de novo renal transplant recipients remained stable throughout the follow-up period without influence of BKV replication. In group B, incidence of viremia and viruria were 3% (1/34) and 9% (3/34) correspondingly, indicating that after the first post-transplant year the risk of BKV re-activation is diminished. CONCLUSION: The highest incidence of BK viremia and viruria is observed the third post-transplantation month, confirming previously published studies in Europe and the United States, and long-term follow up shows that BKV replication decreases significantly after the third post-transplant month and even transient viremia or viruria does not have an impact on renal function.

Ongoing epidemic of blaVIM-1-positive Klebsiella pneumoniae in Athens, Greece: a prospective survey.

OBJECTIVES: To determine the current frequency and study the characteristics of VIM-1-producing Klebsiella pneumoniae isolates from bloodstream infections in Greek hospitals. METHODS: All blood isolates of K. pneumoniae were prospectively collected during 2004-06 in three teaching hospitals located in Athens. MICs of antibiotics were determined by the Etest. Extended-spectrum- (ESBL) and metallo-beta-lactamase (MBL) production was examined by clavulanate- and EDTA-based techniques, respectively. Isolates were typed by PFGE of XbaI-digested genomic DNA. Detection of bla(VIM-1) and mapping of the VIM-1-encoding integrons were performed by PCR and sequencing. Beta-lactamase activities were analysed by IEF and imipenem hydrolysis was assessed by spectrophotometry. VIM-1-encoding plasmids were transferred to Escherichia coli by conjugation and transformation and characterized by Inc/rep typing and RFLP. RESULTS: Sixty-seven (37.6%) of 178 K. pneumoniae blood isolates were bla(VIM-1)-positive (VPKP); 77.8% of these were from ICUs. All VPKP isolates were multidrug-resistant. The MICs of carbapenems for VPKP varied from the susceptible range to high-level resistance overlapping with those of MBL-negative isolates. The EDTA-imipenem synergy methods had reduced sensitivity in detecting VPKP isolates when the MICs were in the susceptible range. ESBL production was common among VPKP isolates (n = 45, 67.2%) as indicated by resistance to aztreonam and confirmed by a clavulanate-based double-disc synergy test. The responsible ESBL was always an SHV-5-type enzyme as indicated by IEF. PFGE identified eight clusters (A-H) of VPKP isolates with related (>80%) patterns, as well as four unique types. Both inter-hospital spread of several clones and genotypic similarities among susceptible, ESBL-positive and VPKP isolates were also observed. Location of bla(VIM-1) and expression of VIM-1 were studied in 12 isolates representing the eight PFGE clusters. In all isolates, bla(VIM-1) was part of a class 1 integron that also carried aacA4, dhfrI, aadA and sulI. In eight isolates (clusters C, D, G and H), the bla(VIM-1) integron was located in transferable IncN plasmids. A cluster F isolate carried a VIM-1-encoding, self-transferable plasmid that was not typeable by Inc/rep typing. VIM-1-encodingreplicons were not identified in three isolates (PFGE clusters A, B and E). VPKP isolates exhibited differences in imipenem-hydrolysing activities which, however, were not correlated with the respective carbapenem MICs. CONCLUSIONS: A multiclonal epidemic of bla(VIM-1)-carrying K. pneumoniae is under way in the majorhospitals in Greece. Microorganisms producing both VIM-1 and SHV-5 constitute the prevalent multidrug-resistant population of K. pneumoniae in this setting.

Efficacy of deoxycholate amphotericin B and unilamellar liposomal amphotericin B in prophylaxis of experimental Aspergillus fumigatus endocarditis.

OBJECTIVE: To evaluate and compare in vivo the protective efficacy of unilamellar liposomal amphotericin B (L-AmB) with that of deoxycholate amphotericin B (D-AmB) in experimental endocarditis. MATERIAL AND METHODS: In the rabbit model of experimental Aspergillus fumigatus endocarditis, two doses of each antifungal agent (1.5 mg/kg each) were administered intravenously at 4 hours and at 30 minutes before challenge with an inoculum of A. fumigatus. Three days later, the animals were sacrificed, and the aortic vegetations were analyzed. RESULTS: All 19 animals that did not receive chemoprophylaxis acquired endocarditis. In contrast, endocarditis developed in 2 of 10 animals pretreated with D-AmB (P < 0.01) and 3 of 8 animals pretreated with L-AmB (P < 0.01). Both D-AmB and L-AmB prevented the development of endocarditis due to A. fumigatus and decreased the concentration of fungi in the aortic vegetations by more than 1 log10. CONCLUSION: In the rabbit experimental model of Aspergillus endocarditis, D-AmB and L-AmB were equally effective in reducing the incidence of the infection and the tissue burden of fungi.

Comparative in vitro and in vivo efficacy of roxithromycin and erythromycin against a strain of methicillin-susceptible Staphylococcus epidermidis.

The in vitro and in vivo efficacy of roxithromycin was compared with that of erythromycin, against a methicillin-susceptible strain of Staphylococcus epidermidis. We performed standard in vitro testing (MIC, MBC, and time-kill kinetics) for roxithromycin, erythromycin, and rifampin. Both macrolides were bacteriostatic in vitro. There was no significant difference in microbial survival between erythromycin and roxithromycin groups in the time-kill kinetics (p = 0.3). For the in vivo experiments, using the rabbit experimental endocarditis model, roxithromycin was found to be inferior to erythromycin in decreasing the microbial burden of the endocardial vegetations (p < 0.05). Rifampin was highly effective, both in vitro and in vivo. In conclusion, the efficacy of roxithromycin was poor and inferior to erythromycin against a strain of methicillin-susceptible S. epidermidis.

Infective endocarditis in Greece: a changing profile. Epidemiological, microbiological and therapeutic data.

The epidemiology, and clinical and microbiological spectrum, of infective endocarditis (IE) in Greece was analysed in a prospective 4-year study in a tertiary hospital and a heart surgery centre in Athens. In total, 101 cases of IE (71 men, 30 women, aged 54.4 +/- 17.1 years) were studied, with a follow-up period of 3 months. Seventy-seven cases were definite and 24 possible; 59 involved native valves (native valve endocarditis; NVE), 31 prosthetic valves (prosthetic valve endocarditis; PVE), of which nine were early and 22 late, and 11 permanent pacemakers (pacemaker endocarditis; PME). There was a predominant involvement of aortic (48/101) and mitral (40/101) valves. Seven patients had rheumatic valvular disease, two had mitral valve prolapse, and eight had a previous history of IE. Thirteen and six patients had undergone dental and endoscopic procedures, respectively. In 13 patients, intravenous catheters were used within the 3 months before diagnosis of IE. There were three intravenous drug users among the patients. Staphylococcus aureus was the most important pathogen, isolated in 22% of cases, followed by viridans streptococci (19%) and coagulase-negative staphylococci (16%). Enterococcus spp. were responsible for 3%, HACEK group for 2%, and fungi for 6% of cases. Viridans streptococci were the leading cause of NVE (29%), Staphylococcus epidermidis of PVE (16%), and S. aureus of PME (54.5%). Six of 22 S. aureus and ten of 16 S. epidermidis isolates were methicillin-resistant. Surgical intervention, including total pacemaker removal, was performed in 51.5% of patients. Overall mortality was 16%, but was 29% with PVE, and was significantly higher with medical than with combined surgical and medical therapy (24.5% vs. 8%). Compared with previous studies, there were changing trends in the epidemiology, microbiology, treatment and prognosis of IE in Greece.

Extended-spectrum beta-lactamase types in Klebsiella pneumoniae and Escherichia coli in two Greek hospitals.

Seventy-nine Klebsiella pneumoniae and 124 Escherichia coli clinical strains, isolated consecutively during August-October 2001 in two Greek hospitals, were examined for production of extended-spectrum beta-lactamases (ESBLs). Seventy-one (35%) isolates (46 K. pneumoniae and 25 E. coli) were ESBL-positive by phenotypic methods. Isoelectric focusing of beta-lactamases and PCR assays for bla genes showed that SHV-5-type ESBLs were the most frequent (45 isolates, 22%) followed by CTX-M (24 isolates, 12%) and IBC (three isolates, 1.5%). The latter two ESBL types may have been established recently in this setting.

Management and outcome of severe diabetic foot infections.

We evaluated the bacteriological and clinical efficacy of the combination of ciprofloxacin/clindamycin in severe diabetic foot infections and we tried to elucidate the relationship between the vascular status of the lower limbs and the outcome of these infections. Initial empirical antibiotic therapy with ciprofloxacin (300 mg/12 hrs IV) and clindamycin (600 mg/8 hrs IV) was administered in 84 hospitalized diabetics with severe lower limb infections. This treatment was continued only in cases with primary clinical improvement. The major endpoints of treatment were: cure, improvement and failure. Evaluation of the vascular status of the lower extremities was performed by high resolution imaging coloured ultrasonography, US-Doppler and TcPO2 measurements. Polymicrobial flora was found in 83% of the cases with an average 2.8 species per specimen. Osteomyelitis was detected in 58 % of the patients. After five days of IV administration of ciprofloxacin and clindamycin the response rate was 95.2%. After three weeks of therapy the clinical outcome was: cure 54.8%, improvement 23.8%, and failure 21.4%. The long term follow up (mean duration 16 months) revealed complete healing of the skin lesions in 63 patients (75%). Unfavorable prognostic factors for these infections were: ankle systolic blood pressure <50 mmHg or toe systolic blood pressure < 30 mmHg and TcPO2 < 20 mmHg. The side effects of the combination of ciprofloxacin/clindamycin were mild and there were no cases of pseudomembranous enterocolitis. The combination of ciprofloxacin/clindamycin was found to provide an excellent empirical as well as definitive treatment of severe diabetic foot infections. The evaluation of the vascular status and the severity of ischaemia of the lower limbs has a strong predictive value in the outcome of these infections.

In vitro evaluation of cefodizime, cefuroxime, ceftriaxone against respiratory pathogens.

The in vitro activity of cefodizime and two comparative cephalosporins, cefuroxime and ceftriaxone were studied against respiratory pathogens. MIC90s of cefodizime were 0.06-0.512 microgram/ml for Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae. MIC50s of cefodizime for Klebsiella pneumoniae and Staphylococcus aureus isolates were 2 micrograms/ml and 8 micrograms/ml respectively. Cefuroxime and ceftriaxone at a concentration of 2 micrograms/ml and 1 microgram/ml inhibited 50% of Klebsiella pneumoniae and 50% of Staphylococcus aureus strains studied respectively. Cefodizime inhibited many of the important respiratory pathogens and can be suggested as an active antimicrobial agent for respiratory tract infections.

Occurrence and antibiotic-resistance of Pseudomonas species isolated from drinking water in southern Greece.

A total of 194 samples of drinking waters consisting of 88 tap waters and 106 non-carbonated bottled waters were processed for isolation of Pseudomonas species during a 4-month period according to standard methods. Pseudomonas aeruginosa was the predominant isolated Pseudomonas species. Twenty-eight (14.4%) P. aeruginosa were isolated from 194 samples. Eight (9%) were isolated from 88 tap water samples and 20 (18.8%) from 106 bottled water samples. Eight (9%) tap waters yielded non-P. aeruginosa strains while bottled waters yielded 22 (20.7%) non-P. aeruginosa strains (P < 0.05). Antibiotic-resistant strains of Pseudomonas species have been isolated from the drinking waters. All but Pseudomonas stutzeri species had a multiple chloramphenicol-erythromycin resistance phenotype. Streptomycin and tetracycline resistance for P. aeruginosa was invariably accompanied by chloramphenicol, tetracycline, erythromycin and nalidixic acid resistance. The susceptibility of Pseudomonas species to newer antimicrobial agents (beta lactams, aminoglycosides, third generation cephalosporins and quinolones) was also evaluated. Ceftazidime and ciprofloxacin seemed to be the most active molecules. There were no resistant P. aeruginosa and P. stutzeri strains to all newer antibiotics tested while Pseudomonas maltophilia was the most resistant among the tested species (69.2% resistance for the newer antibiotics).

Bacterial susceptibilities to piperacillin/tazobactam in a tertiary care hospital: 5-year review.

Several factors influence the speed of development of antibacterial resistance, among which is the amount of antibiotic consumption. During the 3-year period 1998-2000, the consumption of piperacillin/tazobactam (pip/tazo) increased by 85% in our hospital. Five years ago we conducted a comparative in vitro study to evaluate susceptibilities of microorganisms to pip/tazo. The objective of the present study was to re-evaluate in vitro susceptibilities to pip/tazo, compared to other beta-lactams, and the potential impact its increased consumption might have on its susceptibility patterns. The study was performed between November 2000 and April 2001. As in 1996, of the beta-lactams studied, pip/tazo and imipenem had the highest susceptibility rates against selected pathogens (>90% susceptibility rates). P. aeruginosa susceptibilities to both imipenem and pip/tazo were high (97% for both). P. aeruginosa susceptibilities to cefepime were lower. Despite its increased use, pip/tazo retained its initially observed high susceptibility rates for the study pathogens.

Comparative in vitro evaluation of piperacillin/tazobactam in a tertiary care hospital.

Bacterial resistance is usually a serious problem in tertiary care hospitals. The aim of this in vitro study was to evaluate the beta-lactamase inhibitor combination piperacillin/tazobactam in a hospital environment with high bacterial resistance rates and compare it with other beta-lactam agents. Three hundred and sixty-two isolates from various clinical materials were studied during the period March-August 1996. Material for culture was collected from patients of all the wards of our hospital, with the majority being from the Intensive Care Unit (45%). Pathogenic Gram-positive and Gram-negative bacteria with high resistance rates and beta-lactamase production were studied (staphylococci, enterococci, Enterobacteriaceae, Pseudomonas). Significant bacterial resistance rates were identified for ceftazidime (50% for Klebsiellae, 60% for Enterobacter spp, 60% for Proteus spp, 33% for Pseudomonas spp, 75% for Acinetobacter spp) and ciprofloxacin (33% for both Klebsiellae and Enterobacter spp, 67% for Pseudomonas spp, 50% Acinetobacter spp). Fifty percent of Enterococcus isolates were resistance to ciprofloxacin but all of them were susceptible to piperacillin/tazobactam, amoxicillin/clavulanate and imipenem. The antibacterial activity of piperacillin/tazobactam (susceptibility rates 83 to 100% for Enterobacteriaceae, 83% for Pseudomonas spp and 75% for Acinetobacter spp) was higher than that of ceftazidime, piperacillin and ciprofloxacin. Imipenem, being mostly a reserve product, showed higher activity against Acinetobacter, Klebsiella and Enterobacter species.

Ureaplasma urealyticum and infected renal calculi.

In a group of 41 patients with infection lithiasis, the presence of Ureaplasma urealyticum in urine and in the calculi was investigated. A control group of 27 patients with metabolic lithiasis was simultaneously evaluated. Ureaplasma urealyticum was detected in a total of 10 patients with infection lithiasis. In 7 of those patients, U. urealyticum was the only urease producing microorganism detected, while in the remaining 3 it was detected along with common bacteria. We believe that U. urealyticum may be considered as a possible causative factor of infection lithiasis.

Effect of transient BK viremia and viruria on long-term renal allograft survival and function.

INTRODUCTION: The purpose of this study is to present the five-year survival and function of the renal allograft of recipients who were diagnosed with BK viremia and viruria during the first year after renal transplantation. PATIENTS AND METHODS: BK virus was studied in 32 new renal allograft recipients, from the first postoperative day until 18 months after the transplantation. Real-time polymerase chain reaction was used to detect and quantitate BK viral load in serum and urine samples. RESULTS: Qualitative analysis with PCR for the DNA of BK virus showed 31 (31/228, 14%) positive serum samples originating from 20 (20/32, 62%) renal allograft recipients and 57 (57/228, 25%) positive urine samples originating from 23 (23/32, 72%) recipients. During the follow up period of 5 years, renal allograft function remained stable (eGFR 18(th) month: 53.9 ± 23.9 mL/min/1.73 m(2) and eGFR 5(th) year: 52.6 ± 20.6 mL/min/1.73 m(2)). Comparison of recipients that presented with either BK viremia or viruria with a group that did not present viral reactivation did not reveal a statistically significant difference in eGFR. Furthermore, recipients with significantly high viral load in serum or urine did not present renal allograft dysfunction. CONCLUSION: BK virus is potentially pathogenic in renal allograft recipients. It is certain that there is a reactivation of the virus in a high percentage of transplanted patients mostly in the first year after the surgery, without however a negative effect of the transient viremia and viruria in renal allograft function.

Risk factors for and influence of bloodstream infections on mortality: a 1-year prospective study in a Greek intensive-care unit.

To determine the incidence, risk factors for, and the influence of bloodstream infections (BSIs) on mortality of patients in intensive-care units (ICUs), prospectively collected data from all patients with a stay in an ICU >48 h, during a 1-year period, were analysed. Of 572 patients, 148 developed a total of 232 BSI episodes (incidence 16.3 episodes/1000 patient-days). Gram-negative organisms with high level of resistance to antibiotics were the most frequently isolated pathogens (157 strains, 67.8%). The severity of illness on admission, as estimated by APACHE II score (OR 1.07, 95% CI 1.04-1.1, P<0.001), the presence of acute respiratory distress syndrome (OR 3.57, 95% CI 1.92-6.64, P<0.001), and a history of diabetes mellitus (OR 2.37, 95% CI 1.36-4.11, P=0.002) were risk factors for the occurrence of BSI whereas the development of an ICU-acquired BSI was an independent risk factor for death (OR 1.76, 95% CI 1.11-2.78, P=0.015). Finally, the severity of organ dysfunction on the day of the first BSI episode, as estimated by SOFA score, and the level of serum albumin, independently affected the outcome (OR 1.44, 95% CI 1.22-1.7, P<0.001 and OR 0.47, 95% CI 0.23-0.97, P=0.04 respectively).