Effectiveness of gloves in the prevention of hand carriage of vancomycin-resistant enterococcus species by health care workers after patient care.

Gloving reduces acquisition of vancomycin-resistant Enterococcus species (VRE) on the hands, and it should be considered for routine inpatient care, even for contact with the intact skin of patients who may be colonized with VRE. However, gloving does not completely prevent contamination of the hands, and hand washing is necessary after glove removal.

Epidemiology of ciprofloxacin resistance and its relationship to extended-spectrum beta-lactamase production in Klebsiella pneumoniae isolates causing bacteremia.

A prospective study of Klebsiella pneumoniae bacteremia was performed in 12 hospitals in 7 countries. Of 452 episodes of bacteremia, 25 (5.5%) were caused by K. pneumoniae that was resistant in vitro to ciprofloxacin. Extended-spectrum beta-lactamase (ESBL) production was detected in 15 (60%) of 25 ciprofloxacin-resistant isolates, compared with 68 (16%) of 427 ciprofloxacin-susceptible strains (P=.0001). Multivariate analysis revealed that risk factors for ciprofloxacin resistance in K. pneumoniae included prior receipt of a quinolone (P=.0065) and an ESBL-producing strain (P=.012). In all, 18% of ESBL-producing isolates were also ciprofloxacin-resistant. Pulsed-field gel electrophoresis showed that 11 of the 15 ciprofloxacin-resistant ESBL-producing strains belonged to just 4 genotypes, suggesting that patient-to-patient transmission of such strains occurred. The close relationship between ESBL production and ciprofloxacin resistance is particularly worrisome because the first reported instance of plasmid-mediated ciprofloxacin resistance has been in an isolate of K. pneumoniae also possessing an ESBL.

Prolonged suppressive antibiotic therapy for infected orthopedic prostheses.

Prolonged suppressive antibiotic therapy may be an alternative to removal of infected orthopedic prostheses in some patients. However, the efficacy of prolonged suppressive antibiotics is not well established. We retrospectively reviewed 18 patients with infected orthopedic prostheses who had been treated with prolonged antimicrobial suppression during the last 10 years. Eighteen episodes of infection were identified in these 18 patients. There were nine men and nine women, and the mean age was 66 years (range, 31-83 years). All patients had a functional prosthesis and were treated with surgical debridement, retention of the prosthesis, and administration of intravenous antibiotics for 6-8 weeks, followed by prolonged oral antibiotic suppression. Fifteen of the 18 patients appear to have had a good response and have been able to retain a functional prosthesis. Complications related to antibiotic suppression occurred in 22% but did not necessitate discontinuation of the antibiotic therapy. Prolonged antibiotic suppression is a reasonable alternative to surgery in selected patients with infected orthopedic prostheses.

Skin colonization with vancomycin-resistant enterococci among hospitalized patients with bacteremia.

To assess the prevalence of skin and rectal colonization by vancomycin-resistant enterococci (VRE) in hospitalized bacteremic patients and to determine the relation between colonization and bacteremia, we compared 14 case patients who had bacteremia due to VRE with 30 control patients who had bacteremia due to other pathogens. Rectal colonization and skin (inguinal area and/or antecubital fossa) colonization with VRE were common among both case patients (100% had rectal colonization, and 86% had skin colonization) and control patients (37% had rectal colonization and 23% had skin colonization). Among patients with rectal colonization, skin colonization was more common when diarrhea or fecal incontinence was present. The bloodstream cleared without appropriate antimicrobial therapy in nine of the 14 patients with bacteremia due to VRE. The high prevalence of skin colonization with VRE may increase the risk of catheter-related sepsis, cross-infection, or blood culture contamination (which may explain the frequent spontaneous resolution of bacteremia due to VRE).

Infectious complications in left ventricular assist device recipients.

The left ventricular assist device (LVAD) has revolutionized the care of patients with heart failure who are awaiting transplantation. Despite reports of significant infection rates associated with LVAD implantation, few data are available concerning the management of LVAD-related infections and their impact on transplantation. Eight (40%) of our first 20 LVAD recipients developed infections. LVAD-related bloodstream infection occurred in three (15%) patients; infection was due to Staphylococcus aureus in one case, coagulase-negative staphylococci in the second case, and S. aureus and Candida tropicalis in the third case. All three patients were treated with courses of antibiotics that were appropriate for prosthetic valve endocarditis and received antibiotics for at least 6 weeks. All infected patients underwent successful transplantation and had no evidence of recurrence of infection up to 16 months postoperatively. Our experience suggests that LVAD infections can be successfully treated without device removal and that cardiac transplantation can be performed in individuals with LVAD-related bloodstream infection.

Ceftazidime-resistant Klebsiella pneumoniae and Escherichia coli bloodstream infection: a case-control and molecular epidemiologic investigation.

In a molecular, microbiologic, and case-control study to describe the epidemiology of ceftazidime-resistant Klebsiella pneumoniae and Escherichia coli bloodstream infection, 32 unique isolates were recovered over 31 months from the blood of patients hospitalized in a 900-bed hospital in Chicago. Multivariate analysis revealed cases occurred more frequently in debilitated nursing home patients with central venous catheters than in younger, healthier patients. Mortality rates were similar for cases and controls. Case-patients were less likely to die if they received appropriate antibiotic treatment within 3 days of bacteremia onset (P = .02). Pulsed-field gel electrophoresis analysis indicated a polyclonal outbreak, with strain-specific temporal and geographic clustering. Isoelectric focusing results suggested that a predominant enzyme, TEM-10, was responsible for the ceftazidime resistance. The resistance gene was usually carried on a large conjugative plasmid. The polyclonality of the resistant strains suggests that ceftazidime resistance due to TEM-10 is now endemic in Chicago.

European Lyme borreliosis: 231 culture-confirmed cases involving patients with erythema migrans.

In 1994, we isolated Borrelia burgdorferi sensu lato from 231 patients with erythema migrans who presented to the University Medical Center in Ljubljana, Slovenia. Samples of erythema migrans-affected skin were placed in media to support the growth of Borrelia species and evaluated in Ljubljana and Chicago. Patients whose cultures were positive included 132 women and 99 men; 136 of these 231 patients recalled a tick bite. Patients noted a rash an average of 24 days after a bite and presented a mean of 34 days after the bite with erythema migrans (mean diameter. 16 cm). Itching (44%) burning (18%), and pain (11%) were the most common local symptoms. Systemic complaints (40%) included headache, fatigue, malaise, and arthralgia. Other than erythema migrans, findings on physical examination were minimal (< 5% had fever, and in < 10% local lymph nodes were affected). Serial serological studies using indirect immunofluorescence assay, ELISA, and Western blot methods were performed, and antibodies to B, burgdorferi sensu lato were detected in < 50% of samples from patients. This is the largest series reported to date of patients with culture-confirmed Lyme borreliosis. It highlights the deficiencies of serological tests in early disease, demonstrates the sensitivity of direct detection methods for evaluation of patients with erythema migrans, and suggests that patients with early Lyme borreliosis in Slovenia may suffer a milder illness than those in the United States.

Molecular characterization of Borrelia burgdorferi sensu lato from Slovenia revealing significant differences between tick and human isolates.

One hundred twenty-nine Slovenian isolates of Borrelia burgdorferi sensu lato derived from patients (69 strains) or Ixodes ricinus ticks (60 strains) were characterized. All of the strains were first- or second-passage isolates obtained in 1992 and 1993 from the same endemic region. The techniques used for the molecular analysis of strains included species-specific polymerase chain reaction (PCR) typing, and pulsed-field gel electrophoretic separation of undigested and MluI-digested genomic DNA. Isolates were identified to the species level by large restriction fragment pattern (LRFP) analysis and the results compared with the species-specific PCR result. Fifty-two patient isolates (75%) were typed as Borrelia afzelii (LRFP MLa1), 6 (9%) as Borrelia garinii (LRFPs MLg1-4), and 11 (16%) as Borrelia burgdorferi sensu stricto. The latter included 9 isolates (13%) with a new LRFP that is not typical of Borrelia burgdorferi sensu stricto and for which the designation MLx is suggested. In contrast, only 32 of 60 (53%) tick isolates were typed as Borrelia afzelii, while 20 strains (33%) were typed as Borrelia garinii and 8 strains (13%) as Borrelia burgdorferi sensu stricto. Three new LRFPs were found among the Borrelia garinii (MLg5 and 6) and Borrelia burgdorferi sensu stricto (MLb15) tick isolates. Large restriction fragment pattern analysis identified new groups of Borrelia burgdorferi sensu lato and revealed an apparent difference in the isolation frequency of different species from patients and ticks in the same endemic region.

Fever in the solid organ transplant patient.

Fever is common in the solid organ transplant patient and may be produced by a variety of processes. The approach to the febrile transplant patient must include an extensive search for infection, which may be aided by considering the organ transplanted, time after transplantation, and the patient's immunosuppressed state. In addition, a number of noninfectious causes of fever exist in this population, including allograft rejection, drug fever, and thromboembolic disease. A review of the pathogens commonly noted in posttransplant patients is presented, emphasizing risk factors for disease, typical time of presentation, and particular organ groups affected. In addition, the authors review the noninfectious causes of fever in the solid organ transplant patient.

Postantibiotic effect of clarithromycin alone and combined with ethambutol against Mycobacterium avium complex.

The postantibiotic effect (PAE) of clarithromycin alone and in combination with ethambutol was determined for two clinical blood isolates of Mycobacterium avium complex. An average PAE, ranging from 5.5 to 18.0 h, was noted for each isolate at each clarithromycin concentration except when isolate B was exposed to clarithromycin at the MIC. The addition of ethambutol did not enhance the PAE observed with clarithromycin alone. The clinical implications of the PAE of clarithromycin for M. avium complex remain to be determined.

Genotypic and phenotypic characterization of Borrelia burgdorferi isolated from ticks and small animals in Illinois.

We have characterized 33 isolates of Borrelia burgdorferi from northern Illinois (32 isolates) and Wisconsin (1 isolate) representing the largest series of midwestern isolates investigated to date. The techniques used for molecular analysis of strains included (i) genospecies typing with species-specific PCR primers, (ii) plasmid profiling by pulsed-field gel electrophoresis of total genomic DNA, (iii) large-restriction-fragment pattern (LRFP) analysis by pulsed-field gel electrophoresis of MluI-digested genomic DNA (J. Belfaiza, D. Postic, E. Bellenger, G. Baranton, and I. Saint Girons, J. Clin. Microbiol. 31:2873-2877, 1993), (iv) sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total proteins, (v) microsequencing of high-performance liquid chromatography-purified peptides derived from proteins showing high levels of expression, (vi) amino acid composition analysis of proteins, and (vii) immunological analysis of proteins with a polyclonal antiserum of human origin. Five reference strains as well as two atypical tick isolates from California (DN127) and New York (25015) were included for comparison. All of the Illinois and Wisconsin isolates were typed as B. burgdorferi sensu stricto with genospecies-specific PCR primers. The isolates were found to be heterogeneous with regard to their plasmid and protein profiles. One isolate from Illinois possessed two large-molecular-size plasmids instead of the usual 49-kb plasmid. Fragment patterns resulting from MluI digestion of genomic DNA from the 33 isolates and strains DN127 and 25015 were separable into six distinct LRFPs, five of which have not previously been described. Strain 25015 and an isolate from Illinois (CT39) shared an unusual LRFP that is not typical of other B. burgdorferi sensu stricto strains, suggesting that they may represent a fifth species of B. burgdorferi sensu lato. Five of the 33 isolates and strains DN127 and 25015 showed high-level expression of proteins with molecular masses of approximately 22 kDa. Investigation of these proteins by microsequencing of individual peptides and total amino acid composition analysis indicated that the 22-kDa proteins expressed by the seven strains were polymorphic OspC proteins. By using a polyclonal serum of human origin, expression of OspC could be detected in all 33 Illinois and Wisconsin isolates.

Comparison of the in vitro activity of levofloxacin and other antimicrobial agents against vancomycin-susceptible and vancomycin-resistant Enterococcus species.

The in vitro activities of levofloxacin and other antibiotics against 133 clinical isolates of vancomycin-resistant and vancomycin-susceptible enterococci were evaluated. Only 14 (39%) of the vancomycin-susceptible isolates and 11 (11%) of the vancomycin-resistant isolates were susceptible to levofloxacin. Levofloxacin exhibited a marked inoculum effect for all enterococci tested. These results suggest that levofloxacin may be of limited use in the treatment of serious enterococcal infections.

Antibiotic therapy in the allergic patient.

A variety of antimicrobial classes are now available. Thus, a careful history and skin testing for hypersensitivity reactions are often not done. It is often easier to give an alternative agent rather than to determine if the person does indeed have a hypersensitivity reaction to a particular drug. There remain situations (e.g., enterococcal endocarditis, neurosyphilis, syphilis in pregnant women), however, in which options for appropriate therapy are limited. In this setting, an accurate history accompanied by appropriate skin testing and desensitization is indicated.

In vitro activity of FK-037. A parenteral cephalosporin.

The in vitro activity of FK-037, a new extended spectrum cephalosporin, was determined against 398 recent clinical isolates consisting of ceftazidime-susceptible and -resistant, aerobic Gram-negative rods, penicillin-susceptible and resistant Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus, methicillin-susceptible S. aureus, methicillin-susceptible coagulase-negative staphylococci, and methicillin-resistant coagulase-negative staphylococci. Comparative drugs included ceftazidime, imipenem, and amikacin. Susceptibility testing was performed using a broth microdilution method. FK-037 showed greater activity than ceftazidime against ceftazidime-susceptible, aerobic Gram-negative rods. FK-037 showed enhanced activity compared with ceftazidime against Gram-positive organisms, including penicillin-resistant S. pneumoniae. Mutational frequencies for representative Gram-negative rods were comparable for FK-037 and ceftazidime.

Bactericidal activities of antibiotics against vancomycin-resistant Enterococcus faecium blood isolates and synergistic activities of combinations.

The effects of teicoplanin (8 micrograms/ml), ampicillin (64 micrograms/ml), imipenem (32 micrograms/ml), and gentamicin (4 micrograms/ml), alone and in combination, against 13 unique blood isolates of vancomycin-resistance (MIC for 90% of isolates tested [MIC90], 512 micrograms/ml), teicoplanin-susceptible (MIC90, 2.0 micrograms/ml), ampicillin-resistant (MIC90, 128 micrograms/ml), and non-beta-lactamase-producing Enterococcus facium (vancomycin-resistant enterococci [VRE] isolates) were evaluated by time-kill studies. All 13 isolates exhibited high-level resistance to streptomycin; 7 isolates exhibited high-level gentamicin resistance (HLGR). After 24 h of incubation, ampicillin (64 micrograms/ml) combined with gentamicin (4 micrograms/ml) was bactericidal against three of the VRE isolates that did not display HLGR. Synergy between ampicillin and gentamicin was not observed against these isolates. Teicoplanin (8 micrograms/ml) alone was bactericidal at 24 h against five of six VRE isolates that lacked HLGR, but was not bactericidal against any HLGR VRE isolate at that time point. The addition of ampicillin (64 micrograms/ml) or imipenem (32 micrograms/ml) to teicoplanin did not significantly enhance the killing of HLGR VRE isolates as a group (P = 0.335). However, there was a trend toward improved killing of some HLGR VRE isolates by teicoplanin plus imipenem. Vancomycin (32 micrograms/ml) combined with ampicillin (64 micrograms/ml) was neither bactericidal nor synergistic against HLGR VRE isolates. Overall, bactericidal activity was attainable against 7 of 13 VRE isolates at 24 h.

In vitro activity of new quinoxaline compounds against Campylobacter species and Clostridium difficile.

SC-44914 and SC-44942-A are two new quinoxaline compounds with a spectrum of activity similar to that of metronidazole. We studied the activity of SC-44914 and SC-44942-A against 35 Campylobacter jejuni, 30 C. coli, and 20 Clostridium (Cl.) difficile and compared it with that of metronidazole by utilizing an agar dilution method. The quinoxalines had little activity against the C. jejuni and C. coli [minimum inhibitory concentration (MIC)90 > or = 64 micrograms/ml]. SC-44914 and SC-44942-A had excellent activity against Cl. difficile (MIC90 < or = 0.06 micrograms/ml for SC 44914, and 0.5 micrograms/ml for SC-44942A).

In vivo development of teicoplanin resistance in a VanB Enterococcus faecium isolate.

Acquired vancomycin resistance in enterococci may be associated with teicoplanin susceptibility (VanB) or teicoplanin resistance (VanA). This paper characterizes the first instance of in vivo emergence of teicoplanin resistance in an Enterococcus faecium strain of VanB phenotype. Vancomycin-resistant (MIC, 256/512 micrograms/mL) E. faecium was isolated intermittently from a patient's blood over 4 months. The MIC of teicoplanin for the first 5 isolates was 1.0 micrograms/mL; it was 64 micrograms/mL for the final 2. Analysis of plasmid and chromosomal DNA revealed the isolates to be of clonal origin. Conjugal transfer of vancomycin resistance was not obtained. A vanB DNA probe hybridized with both teicoplanin-susceptible and resistant isolates, but a vanA probe failed to hybridize with any isolate. SDS-PAGE of membrane proteins from a teicoplanin-resistant isolate revealed constitutive production of a normally inducible 41-kDa protein. These findings challenge the ultimate utility of teicoplanin for treatment of infections caused by vancomycin-resistant enterococci.