Randomized, double-blind, multicenter trial comparing clinafloxacin with imipenem as empirical monotherapy for febrile granulocytopenic patients

Detection of Pathogenic Bacteria From Septic Patients Using 16S Ribosomal RNA Gene-Targeted Metagenomic Sequencing

BACKGROUND

Conventional blood cultures were compared to plasma cell-free DNA-based 16S ribosomal RNA (rRNA) gene polymerase chain reaction (PCR)/next-generation sequencing (NGS) for detection and identification of potential pathogens in patients with sepsis.

METHODS

Plasma was prospectively collected from 60 adult patients with sepsis presenting to the Mayo Clinic (Minnesota) Emergency Department from March through August 2019. Results of routine clinical blood cultures were compared to those of 16S rRNA gene NGS.

RESULTS

Nineteen (32%) subjects had positive blood cultures, of which 13 yielded gram-negative bacilli, 5 gram-positive cocci, and 1 both gram-negative bacilli and gram-positive cocci. 16S rRNA gene NGS findings were concordant in 11. For the remaining 8, 16S rRNA gene NGS results yielded discordant detections (n = 5) or were negative (n = 3). Interestingly, Clostridium species were additionally detected by 16S rRNA gene NGS in 3 of the 6 subjects with gastrointestinal sources of gram-negative bacteremia and none of the 3 subjects with urinary sources of gram-negative bacteremia. In the 41 remaining subjects, 16S rRNA gene NGS detected at least 1 potentially pathogenic organism in 17. In 15, the detected microorganism clinically correlated with the patient's syndrome. In 17 subjects with a clinically defined infectious syndrome, neither test was positive; in the remaining 7 subjects, a noninfectious cause of clinical presentation was identified.

CONCLUSIONS

16S rRNA gene NGS may be useful for detecting bacteria in plasma of septic patients. In some cases of gram-negative sepsis, it may be possible to pinpoint a gastrointestinal or urinary source of sepsis based on the profile of bacteria detected in plasma.

Distribution and clinical determinants of time-to-positivity of blood cultures in patients with neutropenia

OBJECTIVES

Blood cultures (BCs) are essential in the evaluation of neutropenic fever. Modern BC systems have significantly reduced the time-to-positivity (TTP) of BC. This study explores the probability of bacteraemia when BCs have remained negative for different periods of time.

METHODS

All adult patients with neutropenia and bacteraemia were included (January 2012-February 2016). Predictive clinical factors for short (≤16 hours) and long (>24 hours) TTP were determined. The residual probability of bacteraemia was estimated for the scenario of negative BC 24 hours after collection.

RESULTS

The cohort consisted of 154 patients, accounting for 190 episodes of bacteraemia. Median age of 61 years, 60.5% were male. In 123 (64.7%) episodes, BC yielded a single Gram-positive micro-organism and in 49 (25.8%) a Gram-negative micro-organism (median TTP 16.7, 14.5 hours respectively, P < .01). TTP was ≤24 hours in 91.6% of episodes. Central line-associated bacteraemia was associated with long TTP. The probability of bacteraemia if BC had remained negative for 24 hours was 1%-3%.

CONCLUSIONS

The expected TTP offers guidance in the management of patients with neutropenia and suspected bacteraemia. The knowledge of negative BC can support a change in working diagnosis, and impact clinical decisions as soon as 24 hours after BC collection.

Clostridium difficile infection following systemic antibiotic administration in randomised controlled trials: a systematic review and meta-analysis

Antibiotics have been the most important risk factor for Clostridium difficile infection (CDI). However, only data from non-randomised studies have been reviewed. We sought to evaluate the risk for development of CDI associated with the major antibiotic classes by analysing data from randomised controlled trials (RCTs). The PubMed, Cochrane and Scopus databases were searched and the references of selected RCTs were also hand-searched. Eligible studies should have compared only one antibiotic versus another administered systemically. Inclusion of studies comparing combinations of antibiotics was allowed only if the second antibiotic was the same or from the same class or if it was administered in a subset of the enrolled patients who were equally distributed in the two arms. Only a minority of the selected RCTs (79/1332; 5.9%) reported CDI episodes. Carbapenems were associated with more CDI episodes than fluoroquinolones [risk ratio (RR) = 2.44, 95% confidence interval (CI) 1.32-4.49] and cephalosporins (RR = 2.24, 95% CI 1.46-3.42), but not penicillins (RR = 2.53, 95% CI 0.87-7.41). Cephalosporins were associated with more CDIs than penicillins (RR = 2.36, 95% CI 1.32-4.23) and fluoroquinolones (RR = 2.84, 95% CI 1.60-5.06). There was no difference in CDI frequency between fluoroquinolones and penicillins (RR = 1.34, 95% CI 0.55-3.25). Finally, clindamycin was associated with more CDI episodes than cephalosporins and penicillins (RR = 3.92, 95% CI 1.15-13.43). In conclusion, data from RCTs showed that clindamycin and carbapenems were associated with more CDIs than other antibiotics.

Clinafloxacin for Treatment of Burkholderia cenocepacia Infection in a Cystic Fibrosis Patient

Respiratory infection with Burkholderia cenocepacia is associated with accelerated decline in lung function and increased mortality in cystic fibrosis (CF) patients (A. M. Jones, M. E. Dodd, J. R. W. Govan, V. Barcus, C. J. Doherty, J. Morris, and A. K. Webb, Thorax 59:948-951, 2004, http://dx.doi.org/10.1136/thx.2003.017210). B. cenocepacia often possesses innate resistance to multiple antimicrobial classes, making eradication uncommon in established infection (P. B. Davis, Am J Respir Crit Care Med 173:475-482, 2006, http://dx.doi.org/10.1164/rccm.200505-840OE). We report the use of clinafloxacin in a CF patient with advanced B. cenocepacia infection, present pharmacokinetic (PK) data, and discuss the potential therapeutic role of clinafloxacin in patients with this condition.

Clinafloxacin for Treatment of Burkholderia cenocepacia Infection in a Cystic Fibrosis Patient

Respiratory infection with Burkholderia cenocepacia is associated with accelerated decline in lung function and increased mortality in cystic fibrosis (CF) patients (A. M. Jones, M. E. Dodd, J. R. W. Govan, V. Barcus, C. J. Doherty, J. Morris, and A. K. Webb, Thorax 59:948-951, 2004, http://dx.doi.org/10.1136/thx.2003.017210). B. cenocepacia often possesses innate resistance to multiple antimicrobial classes, making eradication uncommon in established infection (P. B. Davis, Am J Respir Crit Care Med 173:475-482, 2006, http://dx.doi.org/10.1164/rccm.200505-840OE). We report the use of clinafloxacin in a CF patient with advanced B. cenocepacia infection, present pharmacokinetic (PK) data, and discuss the potential therapeutic role of clinafloxacin in patients with this condition.

Evaluation of Bloodstream Infections During Chemotherapy-Induced Febrile Neutropenia in Patients with Malignant Hematological Diseases: Single Center Experience

From year to year, it is important to get an overview of the occurrence of causative agents in febrile neutropenic patients to determine the empiric treatment. Thus our aims were to evaluate a four-year period regarding the prevalence of bloodstream infections and the most important causative agents. During this period, 1,361 patients were treated in our hematology ward because of various hematological disorders. 812 febrile episodes were recorded in 469 patients. At that time, 3,714 blood culture (BC) bottles were sent for microbiological investigations, 759 of them gave positive signal. From the majority of positive blood culture bottles (67.1%), Gram-positive bacteria, mainly coagulase-negative staphylococci (CNS), were grown. Gram-negative bacteria were isolated from 32.9% of the positive blood culture bottles, in these cases the leading pathogen was Escherichia coli. The high prevalence of CNS was attributed to mainly contamination, while lower positivity rate for Gram-negative bacteria was associated with the use of broad-spectrum empiric antibiotic treatment.

Secondary Infections in Febrile Neutropenia in Hematological Malignancies: More Than Another Febrile Neutropenic Episode

Objective:

Febrile neutropenic episodes (FNEs) are among the major causes of mortality in patients with hematological malignancies. Secondary infections develop either during the empirical antibiotic therapy or 1 week after cessation of therapy for a FNE. The aim of this study was to investigate the risk factors associated with secondary infections in febrile neutropenic patients.

Materials and Methods:

We retrospectively analyzed 750 FNEs in 473 patients between January 2000 and December 2006.

Results:

Secondary infections were diagnosed in 152 (20%) of 750 FNEs. The median time to develop secondary infection was 10 days (range: 2-34 days). The duration of neutropenia over 10 days significantly increased the risk of secondary infections (p<0.001). The proportion of patients with microbiologically documented infections was found to be higher in primary infections (271/750, 36%) compared to secondary infections (43/152, 28%) (p=0.038). Age; sex; underlying disease; antibacterial, antifungal, or antiviral prophylaxis; blood transfusion or bone marrow transplantation; central venous catheter; and severity of neutropenia did not differ significantly between primary and secondary infections (p>0.05). While fever of unknown origin (p=0.005) and catheter-related bacteremia (p<0.001) were less frequently observed in secondary infections, the frequency of microbiologically (p=0.003) and clinically (p<0.001) documented infections, fungal pneumonias (p<0.001), infections related to gram-positive bacteria (p=0.04) and fungi (p<0.001), and 30-day mortality rate (p<0.001) were significantly higher in cases of secondary infections (p<0.001).

Conclusion:

Secondary infections should be regarded as life-threatening complications of febrile neutropenia. Secondary infections represent a more severe and mortal complication and cannot be regarded just as another FNE.

The risk of seizures among the carbapenems: a meta-analysis

OBJECTIVES

A consensus exists among clinicians that imipenem/cilastatin is the most epileptogenic carbapenem, despite inconsistencies in the literature.

METHODS

We conducted a meta-analysis of all randomized controlled trials comparing carbapenems with each other or with non-carbapenem antibiotics to assess the risk of seizures for imipenem, meropenem, ertapenem and doripenem.

RESULTS

In the risk difference (RD) analysis, there were increased patients with seizure (2 per 1000 persons, 95% CI 0.001, 0.004) among recipients of carbapenems versus non-carbapenem antibiotics. This difference was largely attributed to imipenem as its use was associated with an additional 4 patients per 1000 with seizure (95% CI 0.002, 0.007) compared with non-carbapenem antibiotics, whereas none of the other carbapenems was associated with increased seizure. Similarly, in the pooled OR analysis, carbapenems were associated with a significant increase in the risk of seizures relative to non-carbapenem comparator antibiotics (OR 1.87, 95% CI 1.35, 2.59). The ORs for risk of seizures from imipenem, meropenem, ertapenem and doripenem compared with other antibiotics were 3.50 (95% CI 2.23, 5.49), 1.04 (95% CI 0.61, 1.77), 1.32 (95% CI 0.22, 7.74) and 0.44 (95% CI 0.13, 1.53), respectively. In studies directly comparing imipenem and meropenem, there was no difference in epileptogenicity in either RD or pooled OR analyses.

CONCLUSIONS

The absolute risk of seizures with carbapenems was low, albeit higher than with non-carbapenem antibiotics. Although imipenem was more epileptogenic than non-carbapenem antibiotics, there was no statistically significant difference in the imipenem versus meropenem head-to-head comparison.

Incidence and management of infections in patients with acute leukemia following chemotherapy in general wards

We hypothesise that treating patients with acute leukaemia in general wards, with proper hygienic and sanitary practices, would result in the minimum utilisation of resources as compared with the corresponding patients receiving ICU support. For this study, the acute leukaemia patients on induction chemotherapy were kept in general wards and observed for the incidence of neutropenia, resultant neutropenic febriles, the causative organism, and the effect of empirical antimicrobial treatment protocol on the outcome of such infections. Prophylactic anti-fungal therapy and cotrimoxazole therapy improved the outcome of infections. The therapy of neutropenic fever and infections must be adapted according to the risk factors and should include early empiric antifungal therapy. It was observed that the treatment of such patients in general wards could be managed effectively, with the added advantage of optimum utilisation of resources and in a patient-friendly environment, at a reasonable cost to the patients.

Epileptogenic potential of carbapenem agents: mechanism of action, seizure rates, and clinical considerations

Antimicrobials are the most frequently implicated class of drugs in drug-induced seizure, with β-lactams being the class of antimicrobials most often implicated. The seizure-inducing potential of the carbapenem subclass may be directly related to their β-lactam ring structure. Data on individual carbapenems and seizure activity are scarce. To evaluate the available evidence on the association between carbapenem agents and seizure activity, we conducted a literature search of the MEDLINE (1966-May 2010), EMBASE (1974-May 2010), and International Pharmaceutical Abstracts (1970-May 2010) databases. Reference citations from the retrieved articles were also reviewed. Mechanistically, seizure propensity of the β-lactams is related to their binding to γ-aminobutyric acid (GABA) receptors. There are numerous reports of seizure activity associated with imipenem-cilastatin, with seizure rates ranging from 3-33%. For meropenem, doripenem, and ertapenem, the seizure rate for each agent is reported as less than 1%. However, as their use increases and expands into new patient populations, the rate of seizures with these agents may increase. High-dose therapy, especially in patients with renal dysfunction, preexisting central nervous system abnormalities, or a seizure history increases the likelihood of seizure activity. Although specific studies have not been conducted, data indicate that carbapenem-associated seizure is best managed with benzodiazepines, followed by other agents that enhance GABA transmission. Due to the drug interaction between carbapenems and valproic acid, resulting in clinically significant declines in valproic acid serum concentrations, the combination should be avoided whenever possible. Clinicians should be vigilant regarding the possibility of carbapenem-induced seizures when selecting and dosing antimicrobial therapy.

Clostridium difficile-associated diarrhea in a tertiary care medical center

This retrospective, case-control study aimed to identify variables associated with the incidence of Clostridium difficile-associated diarrhea (CDAD) in acute care facilities and to specifically identify the relationship of fluoroquinolones and acid suppressive agents in the development of CDAD. Seventy-one symptomatic patients positive for C. difficile toxin A or B hospitalized for at least 72 hours were compared with 142 control patients hospitalized for at least 72 hours who were not positive for C. difficile toxin A or B. Two controls were matched to one case patient for age within 5 years, unit of admission, and date of admission. The mean ages for cases and controls were 63.5 and 62.7 years, respectively. After adjusting for two confounding variables-hospital stay within 3 months and Charlson Comorbidity Index-conditional multiple logistic regression identified six risk factors for development of CDAD: gastrointestinal procedures within 60 days (odds ratio [OR] 9.1, P < 0.013), levofloxacin exposure (OR 8.2, P < 0.033), moxifloxacin exposure (OR 4.1, P < 0.026), imipenem exposure (OR 14.9, P < 0.014), laxative use (OR 20.2, P < 0.0001), and immunosuppressive use (OR 20.7, P < 0.034). The risk of CDAD after exposure to levofloxacin or moxifloxacin was not significantly different. Acid suppressive therapy was not a risk factor for CDAD development.

Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 update by the infectious diseases society of america

This document updates and expands the initial Infectious Diseases Society of America (IDSA) Fever and Neutropenia Guideline that was published in 1997 and first updated in 2002. It is intended as a guide for the use of antimicrobial agents in managing patients with cancer who experience chemotherapy-induced fever and neutropenia. Recent advances in antimicrobial drug development and technology, clinical trial results, and extensive clinical experience have informed the approaches and recommendations herein. Because the previous iteration of this guideline in 2002, we have a developed a clearer definition of which populations of patients with cancer may benefit most from antibiotic, antifungal, and antiviral prophylaxis. Furthermore, categorizing neutropenic patients as being at high risk or low risk for infection according to presenting signs and symptoms, underlying cancer, type of therapy, and medical comorbidities has become essential to the treatment algorithm. Risk stratification is a recommended starting point for managing patients with fever and neutropenia. In addition, earlier detection of invasive fungal infections has led to debate regarding optimal use of empirical or preemptive antifungal therapy, although algorithms are still evolving. What has not changed is the indication for immediate empirical antibiotic therapy. It remains true that all patients who present with fever and neutropenia should be treated swiftly and broadly with antibiotics to treat both gram-positive and gram-negative pathogens. Finally, we note that all Panel members are from institutions in the United States or Canada; thus, these guidelines were developed in the context of North American practices. Some recommendations may not be as applicable outside of North America, in areas where differences in available antibiotics, in the predominant pathogens, and/or in health care-associated economic conditions exist. Regardless of venue, clinical vigilance and immediate treatment are the universal keys to managing neutropenic patients with fever and/or infection.

Executive Summary: Clinical Practice Guideline for the Use of Antimicrobial Agents in Neutropenic Patients with Cancer: 2010 Update by the Infectious Diseases Society of America

This document updates and expands the initial Infectious Diseases Society of America (IDSA) Fever and Neutropenia Guideline that was published in 1997 and first updated in 2002. It is intended as a guide for the use of antimicrobial agents in managing patients with cancer who experience chemotherapy-induced fever and neutropenia.

Recent advances in antimicrobial drug development and technology, clinical trial results, and extensive clinical experience have informed the approaches and recommendations herein. Because the previous iteration of this guideline in 2002, we have a developed a clearer definition of which populations of patients with cancer may benefit most from antibiotic, antifungal, and antiviral prophylaxis. Furthermore, categorizing neutropenic patients as being at high risk or low risk for infection according to presenting signs and symptoms, underlying cancer, type of therapy, and medical comorbidities has become essential to the treatment algorithm. Risk stratification is a recommended starting point for managing patients with fever and neutropenia. In addition, earlier detection of invasive fungal infections has led to debate regarding optimal use of empirical or preemptive antifungal therapy, although algorithms are still evolving.

What has not changed is the indication for immediate empirical antibiotic therapy. It remains true that all patients who present with fever and neutropenia should be treated swiftly and broadly with antibiotics to treat both gram-positive and gram-negative pathogens.

Finally, we note that all Panel members are from institutions in the United States or Canada; thus, these guidelines were developed in the context of North American practices. Some recommendations may not be as applicable outside of North America, in areas where differences in available antibiotics, in the predominant pathogens, and/or in health care–associated economic conditions exist. Regardless of venue, clinical vigilance and immediate treatment are the universal keys to managing neutropenic patients with fever and/or infection.

Clinical review: balancing the therapeutic, safety, and economic issues underlying effective antipseudomonal carbapenem use

Antipseudomonal carbapenems have played a useful role in our antimicrobial armamentarium for 20 years. However, a review of their use during that period creates concern that their clinical effectiveness is critically dependent on attainment of an appropriate dosing range. Unfortunately, adequate carbapenem dosing is missed for many reasons, including benefit/risk misconceptions, a narrow therapeutic window for imipenem and meropenem (due to an increased rate of seizures at higher doses), increasingly resistant pathogens requiring higher doses than are typically given, and cost containment issues that may limit their use. To improve the use of carbapenems, several initiatives should be considered: increase awareness about appropriate treatment with carbapenems across hospital departments; determine optimal dosing regimens for settings where multidrug resistant organisms are more likely encountered; use of, or combination with, an alternative antimicrobial agent having more favorable pharmacokinetic, pharmacodynamic, or adverse event profile; and administer a newer carbapenem with lower propensity for resistance development (for example, reduced expression of efflux pumps or greater stability against carbapenemases).

Comparative study of clinical characteristics of neutropenic and non-neutropenic adult cancer patients with bloodstream infections

A total of 399 consecutive episodes of bloodstream infections in adult patients with haematologic malignancies and solid tumours were evaluated prospectively over a 26-month period, with the aim of determining the clinical characteristics and the microbiological profile of the patients relative to neutrophil count. The overall 30-day mortality rate was 32% (35% in non-neutropenic patients vs. 26% in neutropenic patients, p=0.05). Main diagnoses were solid tumours (33%) and lymphoma (29%). Most of the episodes of bloodstream infection (58%) occurred in non-neutropenic patients. Acute leukaemia and bone marrow transplantation predominated in the neutropenic group. Non-neutropenic patients tended to be older and to have a higher frequency of solid tumours and advanced or uncontrolled diseases. Indwelling central venous catheters were present in 51% of the episodes, with a predominance of long-term catheters in neutropenic haematologic patients. Concomitant infections were observed more frequently in non-neutropenic patients. There were 1,040 noninfectious comorbid conditions, most of which were present in non-neutropenic patients. The causative pathogens were predominantly gram-negative bacilli (56%). Escherichia coli and Klebsiella pneumoniae were isolated more frequently from neutropenic patients, while Staphylococcus aureus and Acinetobacter spp. were more frequent in non-neutropenic patients. Seventy-four percent of the episodes of candidaemia occurred in patients with central venous catheters, with non-albicans strains predominating. The results of this study highlight the heterogeneity of cancer patients with bloodstream infections and the value of stratifying risk factors and aetiologic agents according to neutrophil count.

Fluoroquinolones vs beta-lactams for empirical treatment of immunocompetent patients with skin and soft tissue infections: a meta-analysis of randomized controlled trials

OBJECTIVE

To compare the effectiveness and safety of fluoroquinolones with beta-lactams in the treatment of patients with skin and soft tissue infections (SSTIs).

METHODS

We searched the PubMed database, Cochrane Database of Controlled Trials, and references of relevant articles for study reports published between January 1980 and February 2006.

RESULTS

Twenty randomized controlled trials that enrolled 4817 patients were included in the analysis. Fluoroquinolones as empirical treatment of patients with SSTIs were more effective than beta-lactams for the clinically evaluable patients (90.4% vs 88.2%; odds ratio [OR], 1.29; 95% confidence interval [CI], 1.00-1.66). This was also true in subset analyses of randomized controlled trials that studied ciprofloxacin (OR, 2.49; 95% CI, 1.45-4.26) and for patients with mild to moderate infections (OR, 1.83; 95% CI, 1.13-2.96). In contrast, no difference was found between the compared regimens for patients with moderate to severe infections (OR, 1.12; 95% CI, 0.80-1.55), for patients who did not receive third-generation cephalosporins as the comparator antibiotic (OR, 0.99; 95% CI, 0.73-1.34), or for the microbiologically evaluable patients (OR, 1.19; 95% CI, 0.89-1.59). Fluoroquinolones were also associated with more adverse effects (19.2% vs 15.2%; OR, 1.33; 95% CI, 1.13-1.57).

CONCLUSION

The high proportion of successfully treated patients in the compared groups of antibiotics and the development of more adverse effects associated with fluoroquinolone use suggest that these antibiotics do not have substantial advantages compared with beta-lactams for empirical treatment of patients with SSTIs.

In vitro activities of 11 fluoroquinolones against 816 non-typhoidal strains of Salmonella enterica isolated from Finnish patients with special reference to reduced ciprofloxacin susceptibility

Background

The number of Salmonella strains with reduced susceptibility to fluoroquinolones has increased during recent years in many countries, threatening the value of this antimicrobial group in the treatment of severe salmonella infections.

Methods

We analyzed the in vitro activities of ciprofloxacin and 10 additional fluoroquinolones against 816 Salmonella strains collected from Finnish patients between 1995 and 2003. Special attention was focused on the efficacy of newer fluoroquinolones against the Salmonella strains with reduced ciprofloxacin susceptibility.

Results

The isolates represented 119 different serotypes. Of all 816 Salmonella strains, 3 (0.4%) were resistant to ciprofloxacin (MIC ≥ 4 μg/ml), 232 (28.4%) showed reduced susceptibility to ciprofloxacin (MIC ≥ 0.125 – 2 μg/ml), and 581 (71.2%) were ciprofloxacin-susceptible. The MIC₅₀ and MIC₉₀ values of ciprofloxacin for these strains were 0.032 and 0.25 μg/ml, respectively, being lower than those of the other fluoroquinolone compounds presently on market in Finland (ofloxacin, norfloxacin, levofloxacin, and moxifloxacin). For two newer quinolones, clinafloxacin and sitafloxacin, the MIC₅₀ and MIC₉₀ values were lowest, both 0.016 and 0.064 μg/ml, respectively. Moreover, clinafloxacin and sitafloxacin exhibited the lowest MIC₅₀ and MIC₉₀ values, 0.064 and 0.125 μg/ml, against the 235 Salmonella strains with reduced susceptibility and strains fully resistant to ciprofloxacin.

Conclusion

Among the registered fluoroquinolones in Finland, ciprofloxacin still appears to be the most effective drug for the treatment salmonella infections. Among the newer preparations, both clinafloxacin and sitafloxacin are promising based on in vitro studies, especially for strains showing reduced ciprofloxacin susceptibility. Their efficacy, however, has not been demonstrated in clinical investigations.

Changes in the etiology of bacteremia in febrile neutropenic patients and the susceptibilities of the currently isolated pathogens

The etiology of bacteremia in febrile neutropenic patients in the past few decades has shifted from gram-negative to gram-positive organisms. Potential reasons include the use of indwelling catheters, local environmental conditions, and the administration of specific antibiotic agents, especially as prophylaxis. Other factors may emerge from new studies, such as the categorization of febrile neutropenic patients into groups at low risk and at high risk of developing serious complications, continuing changes in resistance in the community, the use of antibiotic-coated catheters, and future changes in cytotoxic chemotherapy or antineoplastic therapy. In addition, there has been a drift in susceptibility patterns, with resistance issues seen in the general population of hospitalized patients now emerging in febrile neutropenic patients, as well as some issues specific to these patients. These changes affect empirical therapy as it was practiced a decade ago. Among the most commonly used agents, cefepime and carbapenems continue to show the highest rates of in vitro susceptibility, providing coverage against most gram-positive and gram-negative organisms and reducing the need for glycopeptides. Older agents continue to show degradation of their effectiveness. Among Pseudomonas aeruginosa strains, susceptibility to all agents continues to decline.

Clinafloxacin for the Treatment of Bacterial Endocarditis

We report the results of a prospective, multicenter trial assessing intravenous and oral clinafloxacin treatment for infective endocarditis. Sixty-six patients constituted the final study population. Among the 53 patients with native valve infection, Staphylococcus aureus and Streptococcus viridans were the most common pathogens. Twelve patients with native valve infection required surgery, at which time all valve tissue culture results were negative. The overall success rate for native valve infection was 87%. Single valves were involved in 11 of 13 patients with prosthetic valve endocarditis (PVE), and multiple valves were involved in 2 cases. Enterococcus faecalis was the most common pathogen, causing 4 of the PVE cases. The overall success rate for treatment of PVE was 69%. Patients with PVE who did not respond to treatment presented with complications that predict poor prognosis. Clinafloxacin may be effective for both native and PVE, but further studies are indicated.

Infections in patients with cancer undergoing chemotherapy: aetiology, prevention, and treatment

Patients with cancer who are undergoing chemotherapy are highly susceptible, especially if neutropenic, to almost any type of bacterial or fungal infection. These infections cause substantial morbidity and mortality. Prophylactic use of antibiotics should be avoided, however, since this practice is associated with a risk of emergence of resistant bacteria and it does not lower the risk of death. However, chemoprophylaxis has a role for candidal fungal infections. Because infection in a neutropenic host can be rapidly fatal if not treated, the empirical administration of broad-spectrum intravenous antibiotics is generally indicated for these patients, and the local frequencies, susceptibility, and resistance patterns of various pathogens must be taken into account. Once therapy has been initiated, changes in antibiotic regimens during the first 5 days are useless unless the patient's clinical condition deteriorates substantially. The treatment of invasive fungal infections is particularly difficult. Many unsolved questions remain, and studies are proposed here that may shed light on these issues.

Vancomycin versus placebo for treating persistent fever in patients with neutropenic cancer receiving piperacillin-tazobactam monotherapy

This prospective, double-blind trial assessed whether the addition of a glycopeptide would be able to reduce the time to defervescence in neutropenic patients with cancer who had persistent fever 48-60 h after the initiation of empirical piperacillin-tazobactam monotherapy. Of 763 eligible patients, 165 with persistent fever were randomized to receive piperacillin-tazobactam therapy plus either vancomycin therapy or placebo. Defervescence was observed in 82 (95%) of 86 patients in the vancomycin group and in 73 (92%) of 79 patients in the placebo group (P=.52). The distributions of the time to defervescence were not statistically significant between the 2 groups (estimated hazard ratio, 1.03; 95% confidence interval, 0.75-1.43; P=.75). The number of additional episodes of gram-positive bacteremia and the percentage of patients for whom amphotericin B was empirically added to their therapy regimen were also similar in both groups. This study failed to demonstrate that the empirical addition of vancomycin therapy to the treatment regimen is of benefit to persistently febrile neutropenic patients with cancer.

Evaluation of imipenem 1.5 g daily in febrile patients with short duration neutropenia after chemotherapy for non-leukemic hematologic malignancies and solid tumors: personal experience and review of the literature

Numerous studies have demonstrated efficacy of imipenem-cilastatin, 50 mg/kg/day, as first line therapy in febrile patients with neutropenia of short duration consecutive to cytostatic chemotherapy. However, only two studies used low dosage of this antibiotic as 1.5 g/day, in prospective, double blind, randomized clinical trials, in this indication. Efficacy and tolerability of imipenem-cilastatin 0.5 g three times daily IV in 30-min infusions, as first-line empiric therapy, were retrospectively evaluated in our hematological unit. From January 1996 to September 2000, 30 neutropenic patients (12 females) with 45 febrile episodes were included. Median age was 57.5 years (31-75). Twenty-four of them had lymphomas, 4 solid tumors and 2 myelomas. There were 13 clinically documented infections, (CD, 28.8%), 16 microbiologically documented infections, (MD, 35.6%) and 16 febrile episodes corresponding to fever of unknown origin, (FUO, 35.6%). The median neutrophils count on nadir (n = 44), was 67/mm3 (8-369). The median duration of neutropenia was 5 days (3-15). Bacteremia was observed in 10 patients, urinary tract infection in 3 patients. The most frequently isolated microorganism was Escherichia coli. The overall success rate of the first line therapy was 66.7%. Adverse events were observed in 11.1% of the patients without necessity to stop treatment. The MD infections showed a lower rate of success compared with CD infections and FUO. These data were in accordance with the previous studies. The importance of number of microorganisms (p = 0.007) and of infected sites (p = 0.01) appeared as prognostic factors (univariate analysis). Although imipenem-cilastatin has been used in numerous studies as empiric broad-spectrum antibiotic therapy in the treatment of febrile neutropenic cancer patients, the exact dosage of this antibiotic is still not standardized. However, utilization of this antibiotic in monotherapy at low dosage seems to us to be safe and effective as usual dosage in the antimicrobial treatment ofthe febrile patients with post chemotherapy neutropenia of short duration.

Infections in the neutropenic patient--new views of an old problem

Infection in the neutropenic patient has remained a major clinical challenge for over three decades. While diagnostic and therapeutic interventions have improved greatly during this period, increases in the number of patients with neutropenia, changes in the etiologic agents involved, and growing antibiotic resistance have continued to be problematic. The evolving etiology of infections in this patient population is reviewed by Dr. Donowitz. Presently accepted antibiotic regimens and practices are discussed, along with ongoing controversies. In Section II, Drs. Maki and Crnich discuss line-related infection, which is a major infectious source in the neutropenic. Defining true line-related bloodstream infection remains a challenge despite the fact that various methods to do so exist. Means of prevention of line related infection, diagnosis, and therapy are reviewed. Fungal infection continues to perplex the infectious disease clinician and hematologist/oncologist. Diagnosis is difficult, and many fungal infections will lead to increased mortality even with rapid diagnosis and therapy. In Section III, Dr. Pappas reviews the major fungal etiologies of infection in the neutropenic patient and the new anti-fungals that are available to treat them. Finally, Dr. Rolston reviews the possibility of outpatient management of neutropenic fever. Recognizing that neutropenics represent a heterogeneous group of patients, identification of who can be treated as an outpatient and with what antibiotics are discussed.

In-vitro activity of clinafloxacin compared to ciprofloxacin against Acinetobacter baumannii strains isolated from intensive care unit patients

The activity of clinafloxacin was compared to that of ciprofloxacin against 154 Acinetobacter baumannii strains isolated from patients treated in Intensive Care Units. Minimum inhibitory concentrations (MICs) were determined by the Epsilometer test method. The majority (87.6%) of the A. baumannii strains tested were resistant to ciprofloxacin (MIC range 0.125->32, MIC50 = >32, MIC90 = >32). On the contrary, only 9.7% of the strains tested were resistant to clinafloxacin (MIC range 0.023->4, MIC50 = 0.75, MIC90 = 2). Due to its superior activity shown against A. baumannii strains, compared to ciprofloxacin, clinafloxacin may be added to the therapeutic armamentarium for hospital-acquired infections caused by A. baumannii in Intensive Care Units.

A prospective, randomized, multicenter comparative study of clinafloxacin versus a ceftriaxone-based regimen in the treatment of hospitalized patients with community-acquired pneumonia

In an open-label, phase 3, randomized, multicenter study, clinafloxacin (200 mg/d) was compared to ceftriaxone (2 g/d; with or without erythromycin) in 527 patients with acute community-acquired bacterial pneumonia (CAP). Primary efficacy parameters were clinical cure rate and microbiologic eradication rates (by pathogen and by patient) determined 5-9 d post-therapy (test of cure; TOC). Clinical cure rates at TOC for the 2 treatment groups were equivalent in the intention-to-treat (clinafloxacin 79.3, ceftriaxone 78.6%), clinically evaluable (clinafloxacin 88.1, ceftriaxone 85.0%), modified intention-to-treat (clinafloxacin 82.6, ceftriaxone 86.9%) and microbiologically evaluable populations (clinafloxacin 86.2, ceftriaxone 86.2%). Microbiologic eradication rates were similar in the 2 treatment groups. Both drugs were tolerated. Treatment of hospitalized CAP patients with clinafloxacin is a reasonable choice, especially when a resistant pathogen is anticipated.