Serotype distribution of penicillin-resistant pneumococci and their susceptibilities to seven antimicrobial agents

A total of 229 clinical isolates of Streptococcus pneumoniae recovered from 225 patients were serotyped and tested for susceptibility to penicillin G, ampicillin, mezlocillin, cefazolin, erythromycin, clindamycin, chloramphenicol, and sulfamethoxazole-trimethoprim. Of all the isolates, 48 (21.0%) showed intermediate resistance and 17 (7.4%) showed resistance to penicillin G. Penicillin-resistant strains had higher minimal inhibitory concentrations of ampicillin, mezlocillin, and cefazolin than did penicillin-susceptible strains. Resistance to erythromycin and clindamycin was rare (1.3 and 0.9%, respectively). Of the isolates, 8.7% were resistant to sulfamethoxazole-trimethoprim, and all were susceptible to chloramphenicol. Penicillin resistance was associated with 13 serotypes. Serotypes 14, 19F, 19A, and 23F were both highly prevalent and frequently penicillin resistant.     

Pharmacokinetics of ertapenem in healthy young volunteers

Ertapenem (INVANZ) is a new once-a-day parenteral beta-lactam antimicrobial shown to be effective as a single agent for treatment of various community-acquired and mixed infections. The single- and multiple-dose pharmacokinetics of ertapenem at doses up to 3 g were examined in healthy young men and women volunteers. Plasma and urine samples collected were analyzed using reversed-phase high-performance liquid chromatography with UV detection. Ertapenem is highly bound to plasma protein. The protein binding changes from approximately 95% bound at concentrations of <50 micro g/ml to approximately 92% bound at concentrations of 150 micro g/ml (concentration at the end of a 30-min infusion following the 1-g dose). The nonlinear protein binding of ertapenem resulted in a slightly less than dose proportional increase in the area under the curve from 0 h to infinity (AUC(0- infinity )) of total ertapenem. The single-dose AUC(0- infinity ) of unbound ertapenem was nearly dose proportional over the dose range of 0.5 to 2 g. The mean concentration of ertapenem in plasma ranged from approximately 145 to 175 micro g/ml at the end of a 30-min infusion, from approximately 30 to 34 micro g/ml at 6 h, and from approximately 9 to 11 micro g/ml at 12 h. The mean plasma t(1/2) ranged from 3.8 to 4.4 h. About 45% of the plasma clearance (CL(P)) was via renal clearance. The remainder of the CL(P) was primarily via the formation of the beta-lactam ring-opened metabolite that was excreted in urine. There were no clinically significant differences between the pharmacokinetics of ertapenem in men and women. Ertapenem does not accumulate after multiple once-daily dosing.     

Treatment of bone, joint, and vascular-access-associated gram-positive bacterial infections with teicoplanin.

Teicoplanin, a glycopeptide antibiotic, was evaluated for safety and efficacy in the treatment of vascular-access-associated bacteremias and of bone and joint infections due to susceptible gram-positive organisms. Of 35 patients enrolled, 26 had osteomyelitis, 8 had vascular-access-associated bacteremias, and 1 had a joint infection. A total of 38 gram-positive isolates were identified: 23 Staphylococcus aureus and 6 coagulase-negative staphylococcus and 9 streptococcus isolates. After at least 6 months of follow-up, 17 patients were evaluable for efficacy: 10 of 14 (71%) with osteomyelitis and 3 of 3 with vascular-access-associated bacteremias had full resolution of their infections. Inadequate debridement, the presence of metal, and inadequate dosing were likely causes of two failures and two relapses in patients with osteomyelitis. For all but two organisms, teicoplanin MICs were less than or equal to 2 micrograms/ml. Patients who responded had median peak and trough serum bactericidal levels at serum dilutions of 1:64 and 1:16; trough levels of teicoplanin in serum were greater than 30 micrograms/ml. Patients did not respond as expected to daily doses of 4 mg/kg of body weight, which consequently were increased to greater than or equal to 15 mg/kg. Audiology testing of 20 patients found 2 with a mild loss of high-frequency hearing; 1 patient complained of tinnitus. Patients tolerated peak levels in serum as high as 127 micrograms/ml and trough levels of 49 micrograms/ml. However, 5 of 18 patients (28%) whose daily dose was greater than or equal to 12 mg/kg developed drug fever and rash and had teicoplanin discontinued. Further study of the antibiotic at such higher doses is needed.     

Treatment of bone, joint, and soft-tissue infections with oral ciprofloxacin.

We treated 52 patients with orally administered ciprofloxacin. In this study of 34 men and 18 women who completed therapy and who could be evaluated, there were 29 patients with nonhematogenous osteomyelitis, 20 patients with skin or soft-tissue infections, and 3 patients with joint infections. During the study, 92 isolates of pathogenic facultative aerobic bacteria, including 37 members of the family Enterobacteriaceae, 30 Staphylococcus aureus isolates, and 21 Pseudomonas aeruginosa isolates, were recovered, and 88 (96%) of the isolates were found to be susceptible to ciprofloxacin. Of the 29 patients with osteomyelitis, 14 have not experienced relapse after a follow-up of at least 1 year. Overall, 61% of infections were resolved, as judged by both clinical and microbiological criteria, during therapy. One patient developed Streptococcus salivarius sepsis during ciprofloxacin therapy, and one patient developed a rash which required discontinuation of ciprofloxacin. Otherwise, there were no serious reactions or complications.     

Requirements for Both Rac1 and Cdc42 in Membrane Ruffling and Phagocytosis in Leukocytes

Specific pathways linking heterotrimeric G proteins and Fc_γ receptors to the actin-based cytoskeleton are poorly understood. To test a requirement for Rho family members in cytoskeletal events mediated by structurally diverse receptors in leukocytes, we transfected the full-length human chemotactic peptide receptor in RAW 264.7 cells and examined cytoskeletal alterations in response to the chemotactic peptide formyl-methionyl-leucyl-phenylalanine (FMLP), colony stimulating factor–1 (CSF-1), IgG-coated particles, and phorbol 12-myristate 13-acetate (PMA). Expression of Rac1 N17, Cdc42 N17, or the GAP domain of n-chimaerin inhibited cytoskeletal responses to FMLP and CSF-1, and blocked phagocytosis. Accumulation of F-actin– rich “phagocytic cups” was partially inhibited by expression of Rac1 N17 or Cdc42 N17. In contrast, PMA-induced ruffling was not inhibited by expression of Rac1 N17, but was blocked by expression of Cdc42 N17, indicating that cytoskeletal inhibition by these constructs was nonoverlapping. These results demonstrate differential requirements for Rho family GTPases in leukocyte motility, and indicate that both Rac1 and Cdc42 are required for Fc_γ receptor– mediated phagocytosis and for membrane ruffling mediated by structurally distinct receptors in macrophages.     

Predicting maternal and behavioral measures of infant pain: the relative contribution of maternal factors

The Sociocommunication Model of Infant Pain [Craig KD, Pillai Riddell R. Social influences, culture and ethnicity. In: Finley GA, McGrath PJ, editors. Pediatric pain: biological and social context, Seattle: IASP Press; 2003.] theorizes that maternal variables influence the pained infant and that the pained infant reciprocally influences maternal responses to the infant. The current analysis examines the relative predictive utility of maternal behavioral and psychosocial variables for both maternal judgments of her infant's pain and behavioral measures of infant pain, after infant factors have been controlled. A convenience sample of 75 mother-infant dyads was videotaped during a routine immunization in a pediatrician's office. Mothers were interviewed on the telephone, within two weeks, to complete a series of questionnaires. Infants were between the ages of 5 and 20 months. Infant pain was measured directly after the immunization using subjective maternal judgments. In addition, both maternal soothing behaviors and infant pain behaviors post-immunization were measured using objective coding systems. During the telephone interview, mothers were asked to recall infant pain levels for the day after the immunization and were also assessed for level of acculturative stress, perceived social support, general relationship style, feelings towards her infant and endorsed psychopathology. Regression analyses suggested that the role of maternal behavioral and psychosocial variables was highly dependent on the infant pain measure being predicted. These results imply that given the dependence of infants on their primary caregivers, quite often mothers, it is important to understand the dynamic influence of infants' behavior on maternal judgments of infants' pain and maternal psychosocial variables on infants' expression of pain.     

Phenotypic changes in influenza-specific CD8+ T cells after immunization of children and adults with influenza vaccines

The effect of trivalent inactivated influenza vaccine (TIV) or live attenuated influenza vaccine (LAIV) on the phenotypes of circulating influenza-specific CD8+ T cells was analyzed by interferon (IFN)-gamma flow cytometry and tetramer staining. In adults, the expression of the T cell differentiation marker CD27 on virus-specific CD8+ T cells decreased after LAIV but increased after TIV. In children, expression of the cytotoxicity molecule perforin in influenza-specific CD8+ T cells increased after TIV but not after LAIV. Among children aged 6 months to 4 years who had not been vaccinated previously and who received 2 doses of TIV, CD27 expression decreased after each dose, whereas perforin expression increased after the second dose. These findings indicate that the phenotypic changes of influenza-specific CD8+ T cells differ depending on the type of vaccine and the age of the vaccinee. These differences are potentially affected by the different routes of vaccination and pathways of antigen presentation for TIV and LAIV.     

Effect of priming polymorphonuclear leukocytes with cytokines (granulocyte-macrophage colony-stimulating factor [GM-CSF] and G-CSF) on the host resistance to Streptococcus pneumoniae in chinchillas infected with influenza A virus

Patients infected with influenza A virus (IAV) are at increased risk for bacterial superinfections, and this occurs in association with depressed polymorphonuclear leukocyte (PMNL) function. Recently, we reported that in vitro exposure of human PMNL to granulocyte-macrophage colony-stimulating factor (GM-CSF) reverses IAV-induced cell dysfunction. The present study used an established animal model of IAV infection to examine whether G-CSF and/or GM-CSF can overcome IAV- induced PMNL dysfunction and thereby prevent secondary infections. Preliminary studies determined a dosing schedule of these cytokines that caused significant priming of chinchilla PMNL. In subsequent studies, animals were inoculated intranasally with IAV (day 1) followed 3 days later by Streptococcus pneumoniae, and administered daily intraperitoneal injections with a cytokine or placebo on days 3 through 9. Animals had blood obtained on multiple occasions for PMNL studies, and were followed-up for evidence of pneumococcal disease. Both cytokines caused significant priming of the PMNL chemiluminescence response and this was associated with reversal of the IAV-induced PMNL dysfunction. However, neither cytokine decreased the incidence of pneumococcal disease.     

Adoptive T cell therapy using antigen-specific CD8+ T cell clones for the treatment of patients with metastatic melanoma: in vivo persistence,migration, and antitumor effect of transferred T cells

Adoptive T cell therapy, involving the ex vivo selection and expansion of antigen-specific T cell clones, provides a means of augmenting antigen-specific immunity without the in vivo constraints that can accompany vaccine-based strategies. A phase I study was performed to evaluate the safety, in vivo persistence, and efficacy of adoptively transferred CD8+ T cell clones targeting the tumor-associated antigens, MART1MelanA and gp100 for the treatment of patients with metastatic melanoma. Four infusions of autologous T cell clones were administered, the first without IL-2 and subsequent infusions with low-dose IL-2 (at 0.25, 0.50, and 1.0 x 10(6) unitsm(2) twice daily for the second, third, and fourth infusions, respectively). Forty-three infusions of MART1MelanA-specific or gp100-specific CD8+ T cell clones were administered to 10 patients. No serious toxicity was observed. We demonstrate that the adoptively transferred T cell clones persist in vivo in response to low-dose IL-2, preferentially localize to tumor sites and mediate an antigen-specific immune response characterized by the elimination of antigen-positive tumor cells, regression of individual metastases, and minor, mixed or stable responses in 8 of 10 patients with refractory, metastatic disease for up to 21 mo.