Bacteremia Due to Viridans Group Streptococci with Diminished Susceptibility to Levofloxacin among Neutropenic Patients Receiving Levofloxacin Prophylaxis

Abstract

Despite the use of levofloxacin prophylaxis during the neutropenic period after autologous peripheral blood stem cell transplantation, viridans group (VG) streptococcal bacteremia developed in 6 (16.2%) of 37 patients who underwent transplantation between 1 January and 25 February 2001 at the Mayo Clinic in Rochester, Minnesota. All 6 patients presented with fever and mucositis after a mean of 4.5 days of neutropenia, and 3 developed septic shock. All 6 VG streptococcal isolates from these patients exhibited distinct patterns on pulsed-field gel electrophoresis. All isolates had diminished susceptibility to levofloxacin, 5 to gatifloxacin, and 4 to moxifloxacin. Quinolone resistance was associated with mutations in the quinolone resistance-determining region of GyrA and (for 1 isolate) of ParC. The use of levofloxacin may select VG streptococci with diminished susceptibility to levofloxacin and other quinolones with enhanced activity against gram-positive organisms and, therefore, may not be optimal for preventing VG streptococcal bacteremia in neutropenic patients.

Antibiotic prophylaxis in neutropenic patients

“…Many reports have documented the emergence of bacteria resistant to fluoroquinolones in units in which prophylaxis is practiced (e.g., see Cometta et al, Kern et al, Baum et al, and Razonable et al [24][25][26][27] ). There are no quantitative data indicating the extent to which patients came to harm as a result.…”

Impact of bloodstream infections on outcome and the influence of prophylactic oral antibiotic regimens in allogeneic hematopoietic SCT recipients

“…11,13,19 Despite the advantage of antibiotic prophylaxis, 13 a major concern remains on the potential of antibiotic prophylaxis to increase antibacterial resistance, particularly the influence of fluoroquinolone exposure. [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] For example, emergence of fluoroquinoloneresistant bacteria in neutropenic patients receiving fluoroquinolone prophylaxis has been well-documented. [21][22][23][24][25][26][27][28][29] Furthermore, the occurrence of cross-resistant or multiple-drug-resistant (MDR) pathogens, such as an increase in MDR Gram-negative bacteria (GNB), 30,[35][36][37][38] increase in nosocomial methicillin-resistant Staphylococcus aureus infections 31,33,34,38,39 and an emergence of extended spectrum beta-lactamase producers, 32 have all been reported in literature.…”

Viridans streptococcal septicaemia in neutropenic patients: role of proinflammatory cytokines

“…In contrast to what is seen in septicaemia due to coagulase-negative staphylococci, it has been described that 3-33% of cases of viridans streptococcal bacteraemia among neutropenic patients are associated with rapid onset of severe septic syndrome including shock and acute respiratory distress syndrome (ARDS). [3][4][5] Viridans streptococci are normally considered to be of low virulence even though they can occasionally cause infections such as subacute endocarditis and, some subgroups, in particular Streptococcus intermedius (milleri), even cause invasive pyogenic infections, including brain, pulmonary and abdominal abscesses, and osteomyelitis, in immunocompetent individuals. 6,7 Relatively little is known about the immunopathogenesis of these diseases.…”

“…7 In contrast, in neutropenic patients, bacteraemia is frequently seen and septic shock syndrome including ARDS has been described. 3,5,18 No cases of viridans streptococcal septic shock syndrome in immunocompetent hosts have been reported, thus, suggesting that host factors must be crucial in the development of septic shock/ARDS. However, in the majority of neutropenic patients, viridans streptococcal bacteraemia resolves without further complications, indicating that bacterial factors may also be relevant.…”