Bacteremia due to fluoroquinolone-resistant Escherichia coli in two immunocompromised patients

Host impairments in patients with neoplastic diseases

Healthy individuals possess an immune system comprising physical barriers, innate and acquired immunity as well as the indigenous microflora that populate the body surfaces. The immune system maintains constant vigilance over the body at the cellular level as well as at the interface between the host integument and the resident microflora. However, neoplastic diseases and their treatment often lead to impaired immunity resulting in an increased risk of infections due to viruses, bacteria, fungi, and protozoa. This chapter explores the various aspects of host impairment focusing on the components of immunity and the interplay between them to explain why it is that these patients succumb to infections per se. In so doing, we hope that the reader will be better equipped to understand the risks patients face so as to anticipate potential infectious complications and implement appropriate measures to help attain successful remission of the neoplastic diseases and maintain the best quality of life for the patient.

The outpatient management of low-risk febrile patients with neutropenia: risk assessment over the telephone

OBJECTIVE

The purpose of this retrospective study is to evaluate the feasibility of the risk assessment over the telephone in the outpatient management of low-risk febrile patients with neutropenia.

MATERIALS AND METHODS

Febrile patients with neutropenia were eligible for outpatient management with oral ciprofloxacin if they demonstrated the following characteristics: resolution of neutropenia expected in <10 days, good performance status, controlled cancer, no symptoms or signs suggesting systemic infection other than fever, and no comorbidity requiring hospitalization. Eligible patients received oral ciprofloxacin (400 mg, three times daily) and were monitored as far as possible by telephone. Risk assessment concerning general condition was carried out over the telephone.

RESULTS

Of the 60 consecutive patients who received neoadjuvant chemotherapy as a phase II trial of docetaxel (60 mg/m(2)) and doxorubicin (50 mg/m(2)) for primary breast cancer, 30 low-risk febrile patients received oral ciprofloxacin. Twenty-seven of these patients (90%) recovered uneventfully without hospitalization and the use of granulocyte colony-stimulating factor. Treatment was considered to have failed in the remaining three (10%) on the account of the need to modify or change their regimens.

CONCLUSIONS

For carefully selected low-risk febrile patients with neutropenia, risk assessment over the telephone may be convenient, and close daily medical scrutiny may be not routinely required in the outpatient.

Antibiotic prophylaxis with meropenem after allogeneic stem cell transplantation

In the present study, we analyze the efficacy of prophylaxis with meropenem in patients receiving a matched related donor allogeneic transplant. In total, 38 patients were sequentially treated with meropenem starting on the day of the first febrile episode (n=17, group A) vs prophylactic meropenem starting on the first day with <500/mm(3) granulocytes (n=21, group B), and maintained until resolution of fever or after granulocyte count >500/mm(3). Of these, 16 (94%) patients in group A developed fever as compared to 16 (76%) in group B (P=0.02). While only one patient in group A did not require first-line antibiotherapy, there were seven (33%) in group B who did not require it (P=0.01) since fever lasted less than 72 h. In addition, 52% patients in group B did not require second-line antibiotics as compared to 11% among patients in group A (P=0.04). In multivariate analysis prophylaxis with meropenem (HR=2.83, 95% CI (1-8.02); P=0.04) and disease status at transplant (HR for early stage=0.15, 95% CI (0.04-0.62); P=0.04) significantly influenced the development of fever. In conclusion, the current pilot study suggests that the use of prophylaxis with meropenem during the period of neutropenia in patients undergoing allogeneic transplantation favorably affects the morbidity of the procedure by reducing febrile episodes.

Ciprofloxacin prophylaxis in patients with acute leukemia and granulocytopenia in an area with a high prevalence of ciprofloxacin-resistant Escherichia coli

BACKGROUND

Infection remains the major cause of morbidity and mortality in patients with neutropenia, and the beneficial effects of oral prophylaxis remain controversial.

METHODS

From 1993 to December 1999, the authors analyzed the clinical and microbiologic outcomes of 144 episodes of febrile neutropenia among adult patients with acute leukemia.

RESULTS

Forty-three consecutive episodes occurred among patients who were on ciprofloxacin prophylaxis during 1993-1996 (ciprofloxacin group), and 101 subsequent episodes occurred among patients who were not exposed to ciprofloxacin prophylaxis (control group). There were no differences in clinical presentation, antibiotic treatment received for the episode, or a worse outcome between groups. The rate of bacteremia was similar (12 of 43 patients [28%] vs. 26 of 101 patients [26%], respectively). There was a trend toward a higher rate of Gram positive bacteremia in the control group (12 of 101 patients [12%] vs. 2 of 43 patients [5%]) and a higher rate of Gram negative bacteremia in the ciprofloxacin group (11 of 43 patients [26%] vs. 15 of 101 patients [15%]). Resistance to fluoroquinolones was greater in Escherichia coli blood isolates from patients in the ciprofloxacin group (7 of 8 patients vs. 2 of 9 patients; P = 0.02).

CONCLUSIONS

The current results suggest that fluoroquinolone prophylaxis for patients with febrile neutropenia may be abandoned safely in areas with a high prevalence of ciprofloxacin-resistant enterobacteria.

The MYSTIC (meropenem yearly susceptibility test information collection) programme

The primary objective of the MYSTIC study is to monitor the performance of meropenem over a period of at least 3 years during which this carbapenem is prescribed in different hospital units thus allowing profiles to be established within individual hospitals. Monitoring is being carried out by assessing the antibiotic susceptibility of bacterial pathogens isolated from patients with a predominate problem of intraabdominal infections (IAI) and/or lower respiratory tract infections (LRTI), treated in specialist centres (haematology wards, the Intensive Care Unit [ICU], cystic fibrosis units) and non-specialised centres. Samples will be collected over each year and tested against meropenem and a set of comparators. The data obtained from the first year of the study (1997) come from 33 centres spread mainly throughout Europe but also in Israel and Mexico. The results shows that meropenem retains its broad spectrum and potency whilst there is evidence that the activity of comparator antibiotics is being eroded by a variety of resistance mechanisms. Data from subsequent years of the programme will determine whether these trends continue and will allow a series of individual centre profiles to be compiled and presented.

Clinical applications of quinolones

The quinolone antimicrobials are the class of inhibitors of bacterial topoisomerases that has been developed most fully for clinical use in human medicine. Initial members of the class had their greatest potency against Gram-negative bacteria, but newly developed members have exhibited increased potency against Gram-positive bacteria and soon agents will be available with additional activity against anaerobic bacteria, providing a broad spectrum of potency. After nalidixic acid, the earliest member of the class which was used for treatment of urinary tract infections, the later fluoroquinolone congeners have had sufficient potency, absorption, and distribution into tissue for additional uses in treatment of sexually transmitted diseases, infections of the gastrointestinal tract, respiratory tract, skin, and bones and joints. Tolerability of these agents in usual doses has been good. Acquired bacterial resistance resulting from clinical uses has occurred in particular among staphylococci and Pseudomonas aeruginosa. Intense drug use and ability of resistant pathogens to spread have also contributed to development of resistance in initially more susceptible pathogens such as Escherichia coli and Neisseria gonorrhoeae in certain settings. Preservation of the considerable clinical utility of the quinolone class for the long term will be affected by the extent to which their use is judicious.

Ciprofloxacin-resistant Escherichia coli emerging in a rehabilitation medical center

A retrospective review of laboratory records from 1988 to 1996 has shown an increased rate of ciprofloxacin-resistant (cip(r)) Escherichia coli in our rehabilitation center. Resistance increased from 0.6% in 1989 to 5.9% in 1996. Of 7870 E. coli strains isolated during this period, 257 cip(r)-E. coli were recovered from 257 patients. The majority (96%) of these resistant strains were isolated from the urine samples. One hundred and twenty strains of cip(r)-E. coli were also resistant to four other fluoroquinolones. MICs ranging from 64 to 512 micrograms/mL were observed in 75% of the strains and > or = 1028 micrograms/mL in 6.4% of the strains. Resistance to ciprofloxacin was due to possible mutations in topoisomerase gyrA.

Characterization of clinical isolates of Escherichia coli showing high levels of fluoroquinolone resistance

During the years 1992 to 1994, an increase in fluoroquinolone-resistant Escherichia coli was observed at the Medical Center of the Technical University in Munich, Germany. Nineteen strains were collected and were thus available for further analysis. Pulsed-field gel electrophoresis showed clonal diversity in all but two strains. The majority of the patients from whom the strains were isolated had been previously treated with fluoroquinolones. Quinolone resistance was associated with mutations of the quinolone resistance-determining region of the gyrA gene in all cases. Direct sequencing of gyrA PCR amplification products revealed a mutation in codon 83 of the gyrA gene. In some instances the Ser-83-->Leu mutation was accompanied by an Asp-87-->Asn or Asp-87-->Gly mutation. Furthermore, the strains exhibited two different genotypes: in almost half of the fluoroquinolone-resistant E. coli strains as well as in the fluoroquinolone-susceptible E. coli reference strains ATCC 25922 and 35218, silent mutations were detected at bases 255, 273, 300, and 333. Although fluoroquinolones solved major problems in antimicrobial chemotherapy, in certain departments of our hospital the number of resistant E. coli isolates has become so high that susceptibility to fluoroquinolones can no longer be taken for granted.

Relationship between quinolone use and emergence of ciprofloxacin-resistant Escherichia coli in bloodstream infections

From 1988 to 1992, 27 of 855 cases of Escherichia coli bacteremia in nonneutropenic adult patients observed at our hospital were due to ciprofloxacin-resistant (CIPRO-R) strains. Eighteen episodes (67%) were community acquired, and nine (33%) were nosocomially acquired. Overall, the rates of E. coli bacteremia caused by CIPRO-R strains increased steadily from 0% in 1988 to 7.5% in 1992 (P < 0.01). There was a statistically significant correlation between the incidence of CIPRO-R E. coli bacteremia and the upward trend in fluoroquinolone (norfloxacin and ciprofloxacin) use in the community (r = 0.974; P = 0.005) as well as in the hospital (r = 0.975; P = 0.005). When we compared the 27 case patients with 54 simultaneous control patients who had ciprofloxacin-susceptible E. coli bacteremia, the case patients more frequently had chronic underlying diseases (71 versus 37%; P = 0.004), urinary tract infection (74 versus 50%; P = 0.03), prior surgery (22 versus 6%; P = 0.02), and prior fluoroquinolone use (63 versus 4%; P < 0.001). A logistic regression analysis identified prior quinolone use as the only independent risk factor for CIPRO-R E. coli bacteremia. In conclusion, our study shows a significant correlation between ciprofloxacin resistance and fluoroquinolone use and indicates that prior fluoroquinolone use seems to be the most important risk factor for CIPRO-R E. coli bacteremia.