Trends in bacterial infections in febrile neutropenic patients: 1986-1992

Infections in childhood acute lymphoblastic leukemia: an analysis of 222 febrile neutropenic episodes

A retrospective analysis was performed on febrile neutropenic episodes in patients with acute lymphoblastic leukemia (ALL) from 1992 to 2002. There were 222 febrile neutropenic episodes in 266 ALL patients with documented ANC < 500/mm(3). Of the 222 episodes, 98 (44%) had documented focus of infection; the rest were fever without focus. There were 274 different sites of infection in the 98 episodes of documented focus of infection; pulmonary infections were the commonest site of infection (27.3%) followed by HEENT (22.9%). Of 69 bacterial isolates, gram-negative bacteria (n = 46, 67%) were twice as common as gram-positive bacteria (n = 23, 33%). Most common site of isolation for gram-negative bacteria was blood (50%) followed by urine (32.6%). Blood (78.3%) was predominant site of isolation of gram-positive bacteria followed by HEENT (8.7%). Escherichia coli (45.7%) was the commonest gram-negative isolate, while Staphylococcus aureus (39%) was the commonest gram-positive bacterial isolate. There were a total of 22 fungal isolates, the majority from urine (n = 12) and HEENT (n = 9). Of the 22 fungal isolates, 19 were detected in induction phase of chemotherapy. A total of 95/222 (42.8%) febrile neutropenic episodes improved with first-line antibiotic therapy, while modification was required in 127 episodes (57.2%). Antifungal therapy was used in 86 episodes (38.7%). There were a total of 13 deaths, 6 each during induction and intensification/consolidation phases, while 1 died during maintenance phase. Of the 13 deaths, 10 had pneumonia, 8 had bacteremia, and 7 had fungal infection. The current study stresses the importance of frequent reviewing of type, frequency, severity, and outcome of infection complications over the years to detect changing epidemiological patterns. The majority of fungal infections were detected during induction chemotherapy, which highlights the need to consider this type of infection in the evaluation of patients.

Assessment of febrile neutropenia episodes in children with acute leukemia treated with BFM protocols

The authors overviewed 239 febrile neutropenia (FN) episodes in 82 pediatric leukemia cases treated with BFM treatment protocols. FN was observed mostly during consolidation therapy. Mucositis was the most identified focus; gram-negative microorganisms were the most identified pathogens. Five patients developed invasive fungal infections. Fever resolved after mean 5.3 days and mean antibiotic administration time was 12.7 days. Addition of G-CSF to antimicrobial therapy shortened the duration of neutropenia, but it did not affect duration of fever resolution and antibiotic administration. The duration of neutropenia, fever resolution, and antibiotic administration was significantly longer in children with acute myeloid leukemia. The authors conclude that children with acute leukemia have severe prolonged neutropenia and are in high risk. In these patients, prediction of the risk of bacteremia based on clinical and laboratory features is important for immediate empiric broad-spectrum antimicrobial therapy and for higher survival rate.

Risk factors for nosocomial urinary tract-related bacteremia: a case-control study

BACKGROUND

Risk factors for bacteremia in patients with hospital-acquired bacteriuria are largely unknown. Given the morbidity and costs associated with nosocomial bacteremia, determining risk factors could enhance the safety of hospitalized patients.

METHODS

We conducted a case-control study within the Veterans Affairs Puget Sound Health Care System. A patient hospitalized between 1984 and 1999 from whom a urine culture and a blood culture grew the same organism > or =48 hours after admission was considered a case. Control patients were those with significant bacteriuria detected > or =48 hours after admission who did not have a positive blood culture. We used logistic regression to determine independent risk factors for bacteremia.

RESULTS

There were 95 cases and 142 controls. Independent, statistically significant predictors of bacteremia included immunosuppressant therapy within 14 days of bacteriuria (odds ratio [OR], 8.13); history of malignancy (OR, 1.94); male sex (OR, 1.88); cigarette use in the past 5 years (OR, 1.26); number of hospital days before bacteriuria (OR, 1.03); and antibiotic use within 3 days of bacteriuria (OR, 0.76). Corticosteroid use within 7 days of bacteriuria predicted bacteremia in patients <70 years old (OR, 14.24). Similarly, patients <70 years old were more likely to develop bacteremia if they had diabetes mellitus (OR, 6.19).

CONCLUSION

Delineating risk factors for nosocomial urinary tract-related bacteremia can help target appropriate preventive practices at the highest risk patients.

Efficacy and safety of linezolid compared with vancomycin in a randomized, double-blind study of febrile neutropenic patients with cancer

BACKGROUND

Gram-positive pathogens can cause serious infections in neutropenic patients with cancer, and vancomycin therapy is often initiated empirically. Linezolid may offer an option for these patients.

METHODS

To compare the safety and efficacy of linezolid and vancomycin in febrile, neutropenic patients with cancer, we conducted a double-blind, multicenter equivalence study. Eligible patients with proven or suspected infection due to a gram-positive pathogen were randomized to receive linezolid or vancomycin.

RESULTS

Clinical success rates 7 days after completion of therapy (primary end point) were equivalent between groups in the intent-to-treat (ITT) analysis (linezolid, 219 [87.3%] of 251 patients; vancomycin, 202 [85.2%] of 237 patients; 95% CI, -4.1 to 8.1; P=.52), modified ITT analysis, clinically evaluable analysis, and microbiologically evaluable analysis, as well as between subsets analyzed by malignancy and infection type. Mean time to defervescence was shorter for linezolid than vancomycin in the modified ITT (6.6 vs. 8.5 days; P=.04) and microbiologically evaluable subsets (5.9 vs. 9.1 days; P=.01), although post hoc analyses revealed delayed recovery of absolute neutrophil counts for linezolid in these subsets (P<.05). There were no between-group differences in microbiologic success rates in the modified ITT subset (41 [57.7%] of 71 patients vs. 29 [50.0%] of 58 patients; P=.38) and microbiologically evaluable subsets, as well as in mortality rates in the ITT subset (17 [5.6%] of 304 patients vs. 23 [7.6%] of 301 patients; P=.31) and all subsets. Distribution of adverse events, including reported hematologic events, was similar between groups, except that linezolid was associated with fewer drug-related adverse events (52 [17.2%] of 303 patients vs. 72 [24.0%] of 300 patients; P=.04) and fewer cases of drug-related renal failure (1 [0.3%] of 303 patients vs. 7 [2.3%] of patients; P=.04).

CONCLUSIONS

Linezolid demonstrated efficacy and similar safety outcomes equivalent to those for vancomycin in febrile neutropenic patients with cancer.

Suspected infection in children with cancer

The microbiology and severity of suspected infections in children with cancer admitted to the John Hunter Children's Hospital was determined in order to assess whether any alteration to the infection treatment protocol was required. All children with cancer aged 1-17 years who had an episode of suspected or proven infection that required parenteral treatment at John Hunter Children's Hospital (JHCH) during 1994/95 were reviewed. Thirty-seven children were treated for cancer at JHCH; 62 admissions for suspected infection which involved 26 children were reviewed. Sixteen of these children had a permanent central line. Children with a central line had an increase in the number of days of inpatient treatment required for the treatment of suspected infection, and they had more episodes of infection. A pathogen was isolated more frequently with blood cultures being positive more often and gram-positive species were methicillin resistant more often. These differences were not statistically significant. A pathogen was isolated in 52% of admissions. Sixteen pathogens were gram positive; 12 were gram negative, two were fungal and two were viral. Blood cultures were positive in 21 of 62 admissions, skin swabs in four admissions, urine cultures in three admissions, stool in two admissions and one species was isolated from an epidural catheter tip and from the sputum. In 16% of admissions, the identified organism was resistant to the initial empirical therapy of tobramycin and piperacillin. In a further 13%, flucloxacillin was added to the empirical regimen when a sensitive Staphylococcus was identified. No significant differences between the culture-negative and culture-positive groups were observed in admission pulse, fever or admission neutrophil count. However, those patients with a central line had a higher incidence of having a pathogen isolated if their temperature was > 39.5 degrees C. The median length of stay was longer for patients with a pathogen isolated on blood culture. Admission blood cultures were positive in 53% of admissions with an initial neutrophil count > 1000 x 10(9)/mL. Each of these children had a central line. Only one child died of infection during the 2-year study period. This review supports the observations that gram-positive infection is now more common than gram-negative infection in children with cancer. Despite the management advantages a permanent central line affords it is clear those children with a central line have an increased rate of infection and there needs to be caution in their use. The most important is the observation that any fever > 39.5 degrees C in a child with a central line is likely to be associated with a documented infection irrespective of the neutrophil count. The clinical outcomes observed in the present study indicate that tobramycin and piperacillin are effective empirical treatments for suspected infection in children with cancer.

Fever in the neutropenic host

Fever in the neutropenic patient following myelosuppressive chemotherapy is a medical emergency. Appropriate antimicrobial therapy can dramatically reduce infection-related morbidity and mortality. This article reviews the rationale and methodology of treatment as well as its applicability to other neutropenic states. The utility of adjunct therapy with granulocyte- stimulating compounds is also discussed.

Hickman catheters: left-sided insertion, male gender, and obesity are associated with an increased risk of complications

BACKGROUND

Semipermanent tunnelled silicone rubber Hickman catheters are widely used to provide durable central venous access for patients with cancer or haematological disease.

AIMS

To document the frequency and severity of Hickman catheter related adverse events and to identify predisposing factors.

METHODS

A retrospective review was undertaken of 153 sequential Hickman catheters inserted into patients receiving treatment for cancer or haematological disease. All Hickman catheters were inserted percutaneously in a radiology department under local anaesthesia and fluoroscopic control. The exact position of the catheter tip was determined by reviewing post-insertion radiographs.

RESULTS

The median duration of catheter use was 55 days (range one-650). Complications led to the removal of 32% of catheters. Exit site infection complicated 22% of catheters, septicaemia 7%, migration or dislodgment 7%, and venous thrombosis 8%. Complications were more common in male patients (exit site infection and catheter loss), in patients with acute leukaemia (septicaemia) and in obese patients (catheter migration). Left sided catheters caused more venous thrombosis and were more likely to malfunction or block. Left sided catheters required removal more frequently than right sided catheters. Termination of the Hickman catheter within the high superior vena cava (SVC) resulted in loss of function earlier when compared to termination with the low SVC or right atrium (RA).

CONCLUSIONS

Right-sided Hickman catheters terminating in the low SVC/RA offer the best chance of durable function. The use of subcutaneously tunnelled catheters in obese patients poses unique problems with catheter migration. Vigilance in the placement and care of Hickman catheters remains essential.