Pulsed-field gel electrophoresis was used to compare 34 isolates of Enterococcus faecium from six different geographic locations. This procedure generated an average of 13 discernible fragment bands per isolate (range, 10 to 19 fragment bands) of 34 to 485 kb. The resulting restriction endonuclease digestion patterns were quite heterogeneous and were able to differentiate 27 of 34 isolates from each other, as defined by one or more mismatched fragment bands. Five patterns were shared by two or more isolates, and each set of isolates with matching patterns (shared pattern) originated in the same medical center, suggesting a common epidemiologic background, including highly penicillin resistant isolates in Richmond and Philadelphia. We conclude that pulsed-field gel electrophoresis of DNA digested with low-frequency-cleavage restriction enzymes offers a relatively simple method of comparing E. faecium for the purpose of epidemiologic study.

BackgroundThe human immunodeficiency virus (HIV) fuels tuberculosis (TB) epidemics. In controlled clinical trials, antiretroviral therapy (ART) reduces TB incidence in HIV-infected patients. In this study we determine if, under programmatic conditions, Brazil's policy of universal ART access has impacted TB incidence among HIV-infected patients.MethodsWe abstracted clinical information from records of HIV-infected patients managed in the public sector in 11 Brazilian states between 1/1/1995 and 12/31/2001. Case ascertainment (TB and HIV) utilized guidelines (with added stringency) published by Brazil's Ministry of Health. We determined TB incidence and hazards ratio (HR) for ART-naïve and ART-treated [including highly active ART (HAART)] patients employing Cox proportional hazards analysis.ResultsInformation from 463 HIV-infected patients met study criteria. The median age of the study population was 34 years, 70% were male, and mean follow-up to primary endpoints—TB, death, and last clinic visit—was 330, 1059, and 1125 days, respectively. Of the 463 patients, 76 (16%) remained ART-naïve. Of the patients who never received HAART (n = 157) 81 were treated with ART non-HAART. Of the patients who received any ART (n = 387), 306 were treated with HAART (includes those patients who later switched from ART non-HAART to HAART). Tuberculosis developed in 39/463 (8%) patients. Compared to HAART- and ART non-HAART-treated patient groups, TB incidence was 10- (p<0.001) and 2.5-fold (p = 0.03) higher in ART-naïve patients, respectively. The median baseline absolute CD4+ T-lymphocyte count for patients who developed TB was not significantly different from that of patients who remained TB free. In multivariate analysis, the incidence of TB was statistically significantly lower in HAART-treated [HR 0.2; 95% (CI 0.1, 0.6); p<0.01] compared to ART naïve patients. A baseline CD4+ T-lymphocyte count <200 cells/mm3 [HR 2.5; (95% CI 1.2, 5.4); p<0.01], prior hospitalization [HR 4.2; (95% CI 2.0, 8.8); p<0.001], prior incarceration [HR 4.1; 95% CI 1.6, 10.3); p<0.01], and a positive tuberculin skin test [HR 3.1; (95% CI 1.1, 9.0); p = 0.04] were independently and positively associated with incident TB.ConclusionIn this population-based study we demonstrate an 80% reduction in incident TB, under programmatic conditions, in HAART-treated HIV-infected patients compared to ART-naïve patients.

Two pairs of oligonucleotide primers were designed to amplify fragments of the genes for Shiga-like toxin I (SLT-I) and SLT-II in a single reaction. A 370-bp segment and a 283-bp segment were amplified for SLT-I and SLT-II, respectively. The specificities of the polymerase chain reaction (PCR) amplification products were confirmed by using radioactively labeled oligonucleotide probes. SLT sequences were amplified from DNA isolated from 13 previously characterized enterohemorrhagic Escherichia coli (EHEC) strains. No amplification product was produced by using DNA from 20 non-EHEC strains. As little as one bacterial genome was detectable. PCR was then applied to DNA isolated directly from stool samples. We had to remove inhibitors of PCR that were present in lysates prepared from stool samples before amplification was achieved. First, we evaluated the sensitivity of PCR for the detection of known numbers of EHEC added to normal stools. Second, three children with SLT in their stools were shown to have SLT sequences in their stools by PCR. Two of these children had hemolytic-uremic syndrome, and a third child was asymptomatic. Stool specimens collected from another 26 asymptomatic children were negative by PCR for SLT sequences. PCR can be used to diagnose EHEC infections without prior culture of stool specimens.

We examined the in vitro activity of PD 127391, an investigational fluoroquinolone antibacterial agent, against staphylococci (including methicillin-resistant Staphylococcus aureus), enterococci (including beta-lactamase-producing and highly gentamicin-resistant isolates), and streptococci. The compound was active against all organisms tested and compared favorably with antimicrobial agents routinely used to treat infections with these organisms. On the basis of MICs for 90% of the strains tested, PD 127391 was 32-fold more active against all staphylococci, 16-fold more active against methicillin-resistant S. aureus, 8-fold more active against all streptococci, and 4-fold more active against all enterococci than ciprofloxacin. PD 127391 was shown to be more active than sparfloxacin, which in turn was shown to be more active than ciprofloxacin, against these gram-positive cocci. PD 127391 shows promise for the treatment of infections with gram-positive cocci, including organisms which are resistant to other commonly used antimicrobial agents.

Pulsed-field gel electrophoresis was used to determine the chromosomal size of three different strains of Enterococcus faecalis and one strain of Enterococcus faecium. The size determinations of OG1X, a strain of E. faecalis widely used in many laboratories for genetic studies, using Sma I, Not I, and Sfi I alone or in combination, ranged from 2,750 to 2,761 kb. Using the same enzymes as with OG1X, the size of HH-67, a plasmid-free clinical isolate of E. faecalis, was determined to be 2,170-2,288 kb and the size of JH2-2, an E. faecalis recipient strain, ranged from 2,008 to 2,135 kb. The size range generated for GE-1, a plasmid-free E. faecium strain, with the use of Sma I, Not I, and Apa I was 2,045-2,155 kb. Although OG1X differed in size from the other three enterococci, each individual enterococcal strain generated reproducible results in different experiments. However, for both E. faecalis OG1X and E. faecium GE-1, one of the enzymes used generated a considerably smaller molecular size than that generated by the other two enzymes. The discrepancy was due to visually undiscernible comigrating fragments, and serves to point out a potential source of error if fewer than two enzymes are used to size a genome. The size discrepancies were resolved by digesting individual fragments with a second enzyme. The molecular sizes of these enterococcal strains are larger than that recently reported for Campylobacter, smaller than that of Escherichia coli and Pseudomonas aeruginosa, and similar (OG1X) or smaller (JH2-2, HH67, and GE-1) than the 2,819-kb reported for Streptococcus mutans.

Targeted tuberculin testing and LTBI treatment is feasible and likely to reduce TB rates over time. Yield and cost-effectiveness are maximized by prioritizing foreign-born persons, a large population with high TB risk.

With prompt initiation of anti-tuberculosis treatment and access to ART, excellent outcomes were achieved in a public health setting in HIV-infected adults who developed TB disease.