Risk factors for extended-spectrum beta-lactamase-producing Enterobacteriaceae in a neonatal intensive care unit.

Risk factors for colonization or infection with extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae during an outbreak in a neonatal intensive care unit (NICU) included low gestational age and exposure to third-generation cephalosporins. We also reviewed the existing medical literature regarding the clinical epidemiology of ESBLs in NICUs .

Sequence-based identification of aerobic actinomycetes.

We investigated the utility of 500-bp 16S rRNA gene sequencing for identifying clinically significant species of aerobic actinomycetes. A total of 28 reference strains and 71 clinical isolates that included members of the genera Streptomyces, Gordonia, and Tsukamurella and 10 taxa of Nocardia were studied. Methods of nonsequencing analyses included growth and biochemical analysis, PCR-restriction enzyme analysis of the 439-bp Telenti fragment of the 65 hsp gene, susceptibility testing, and, for selected isolates, high-performance liquid chromatography. Many of the isolates were included in prior taxonomic studies. Sequencing of Nocardia species revealed that members of the group were generally most closely related to the American Type Culture Collection (ATCC) type strains. However, the sequences of Nocardia transvalensis, N. otitidiscaviarum, and N. nova isolates were highly variable; and it is likely that each of these species contains multiple species. We propose that these three species be designated complexes until they are more taxonomically defined. The sequences of several taxa did not match any recognized species. Among other aerobic actinomycetes, each group most closely resembled the associated reference strain, but with some divergence. The study demonstrates the ability of partial 16S rRNA gene sequencing to identify members of the aerobic actinomycetes, but the study also shows that a high degree of sequence divergence exists within many species and that many taxa within the Nocardia spp. are unnamed at present. A major unresolved issue is the type strain of N. asteroides, as the present one (ATCC 19247), chosen before the availability of molecular analysis, does not represent any of the common taxa associated with clinical nocardiosis.

Disseminated Mycoplasma orale infection in a patient with common variable immunodeficiency syndrome.

Human infection with Mycoplasma species other than M. pneumoniae are infrequent, but may be encountered in patients with immunodeficiencies. We report a patient with combined variable immunodeficiency that developed multiple abscesses and destructive bone disease caused by M. orale, an organism generally considered to be non-pathogenic. Molecular laboratory methods, 16S rRNA sequence analysis, were used to detect the organism directly in the surgical specimen and confirmed following isolating of the organism. This case demonstrates the importance of molecular technology in the diagnosis of difficult infectious disease problems.

Extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella species: risk factors for colonization and impact of antimicrobial formulary interventions on colonization prevalence.

OBJECTIVE: The incidence of extended-spectrum beta-lactamase (ESbetaL)-mediated resistance has increased markedly during the past decade. Risk factors for colonization with ESbetaL-producing Escherichia coli and Klebsiella species (ESbetaL-EK) remain unclear, as do methods to control their further emergence. DESIGN: Case-control study. SETTING: Two hospitals within a large academic health system: a 725-bed academic tertiary-care medical center and a 344-bed urban community hospital. PATIENTS: Thirteen patients with ESbetaL-EK fecal colonization were compared with 46 randomly selected noncolonized controls. RESULTS: Duration of hospitalization was the only independent risk factor for ESbetaL-EK colonization (odds ratio, 1.11; 95% confidence interval, 1.02 to 1.21). Of note, 8 (62%) of the patients had been admitted from another healthcare facility. In addition, there was evidence for dissemination of a single K oxytoca clone. Finally, the prevalence of ESbetaL-EK colonization decreased from 7.9% to 5.7% following restriction of third-generation cephalosporins (P = .51). CONCLUSIONS: ESbetaL-EK colonization was associated only with duration of hospitalization and there was no significant reduction following antimicrobial formulary interventions. The evidence for nosocomial spread and the high percentage of patients with ESbetaL-EK admitted from other sites suggest that greater emphasis must be placed on controlling the spread of such organisms within and between institutions.