[Study of the betalactam resistance of Haemophilus influenzae conferred by the bla(ROB-1) gene]

Given the lack of information on the resistance to betalactams conferred by the bla(ROB-1) gene in our area, we decided to undertake a study to determine if and how often it appears in our isolates. We analyzed the presence of the gene in 177 strains of Haemophilus influenzae and compared the results with those from the biochemical tests (nitrocefin). Sixty-three strains tested positive in the nitrocefin test (35.6%). The presence of the bla(ROB-1) gene was detected in seven of the 177 strains (3.9%). All the strains expressing the gene also tested positive in the nitrocefin test. Of the 63 strains that showed biochemical resistance (positive to nitrocefin), seven were found to be caused by the presence of the bla(ROB-1) gene. An epidemiological follow-up for the presence of this gene in our area is therefore advisable.

Two cases of fungemia due to Candida lusitaniae and a literature review

Reported here are two cases of candidemia caused by Candida lusitaniae that occurred in two immunocompromised patients at Hospital Universitario "La Fe" in Valencia, Spain. Case 1 involved a low-birth-weight premature infant with congenital nephrotic syndrome who was successfully treated with amphotericin B, and case 2 involved a 50-year old woman with a high-grade malignancy lymphoma who succumbed to the infection. Antifungal susceptibility testing of the Candida lusitaniae isolates recovered from both patients revealed sensitivity to amphotericin, 5-flucytosine and fluconazole. Results are presented and discussed together with a comprehensive review of the literature, covering all previously reported cases of fungemia caused by this emerging pathogen.

[Correlation between in vitro susceptibility to antifungal drugs and the clinical evolution of patients with candidiasis and cryptococcosis]

The increase in the incidence of fungal infections and the emergence of resistance call for the development of techniques for measuring in vitro antifungal susceptibility that are useful for predicting clinical outcome in patients suffering from these infections. In the past, the lack of standardized testing techniques led to poor intra- and interlaboratory reproducibility. Recently, the National Committee for Clinical Laboratory Standards (NCCLS) has developed a reference method for antifungal susceptibility testing, document M27A. This document is a necessary and important step towards the standardization of antifungal susceptibility testing, which has important implications in the analysis of clinical and microbiological data. This article provides a comprehensive review of studies correlating in vitro antifungal susceptibility testing and clinical outcome. In general, it is possible to predict the therapeutic outcome, especially in HIV infected patients with oropharyngeal candidiasis treated with fluconazole. However, in other more heterogeneous groups of patients it is more difficult to correlate the in vitro and in vivo data.

[The activity of systemic antimycotic drug combinations]

The treatment of deep mycoses is complex, especially in immunosuppressive patients, owing to several factors: the scarcity of antimycotic drugs, the difficulty of carrying out antimycotic susceptibility tests, the scarcity of in vitro/in vivo correlation studies, the lesser response to therapy in comparison to antibacterial treatment, etc. Aside from this, the adverse effects, therapeutic failure and the appearance of resistance are serious problems that may emerge with the use of antimycotic drugs. These problems can be partly avoided by using combinations of antimycotics. In this article, the results obtained by different authors when using systemic antimycotics in combined therapy are reviewed. The effect of the combination of amphotericin B and azoles varies according to the moment of administration: when the azole is administered before amphotericin B, antagonism between the two has been observed; however, when they are administered simultaneously the effect is synergistic with the hydrophylic azoles (fluconazole), antagonistic with lipophilic azoles (itraconazole) or indifferent. The combination of flucytosine with azoles has been demonstrated to be synergistic on Candida albicans (itraconazole, fluconazole) and on Cryptococcus neoformans (fluconazole). With the combinations of an equinocandine and amphotericin B or fluconazole, synergism has been observed on C. neoformans.

Famciclovir treatment in transplant recipients with HBV-related liver disease: disappointing results

OBJECTIVE

Long-term administration of hepatitis B immune globulin is effective as prophylaxis for hepatitis B virus (HBV) reinfection but is limited by cost, side effects, availability and a failure rate of 20%. Famciclovir has been shown to be effective in the treatment of hepatitis B in the immunocompetent patient. Fewer data exist in the liver transplant setting, particularly regarding its efficacy in de novo HBV infection. The aims of this pilot study were to determine the effectiveness and safety of long-term administration of famciclovir in recurrent (n = 3) and de novo (n = 3) HBV infection after liver transplantation.

METHODS

Six patients with postransplant HBV infection (positivity of serum HBsAg and HBV DNA), four of whom were HBeAg positive, were treated with famciclovir (500 mg, 3 times a day) with a minimum follow-up period of 12 months. Biochemical, serological, virological (HBV DNA by hybridization assays and polymerase chain reaction), and histological (including HBV immunostaining) endpoints were evaluated.

RESULTS

None of the patients had a complete biochemical response, with a near complete normalization of ALT levels being observed in 3/6 patients. There was a lack of correlation between virological and biochemical responses. None of the patients seroconverted to anti-HBs or anti-HBe. A virological clearance was observed in only two patients, whereas a moderate reduction in HBV DNA levels was present in one. HBV DNA levels were higher than levels during pretreatment in the three remaining patients. Histological improvement was only observed in one patient.

CONCLUSION

Famciclovir alone appears of limited efficacy in the treatment of HBV infection after liver transplantation.

Repeated pulmonary infection by Nocardia asteroides complex in a patient with bronchiectasis

A rare case of pulmonary nocardiosis was presented in a nonimmunocompromised patient who had chronic airway obstruction and bronchiectasis without corticoid treatment. The microbial diagnosis was established after isolating Nocardia in bronchial aspirate and sputum samples. An in vitro study showed sensitivity only to imipenem, netilmicine, amikacin and ofloxacin. The evolution was chronic, with multiple clinical recurrences in spite of prolonged antibiotic treatment. Finally, the eradication of Nocardia was achieved with the combination of imipenem and amikacin.

Epidemiological, microbiological, clinical, and prognostic factors of bacteremia caused by high-level vancomycin-resistant Enterococcus species

A case-control study was performed between 1994 and 1996 in order to study the epidemiological, microbiological, clinical, and prognostic features of high-level vancomycin-resistant enterococcal bacteremia. Seventeen consecutive patients who had clinically significant bacteremia due to vancomycin-resistant enterococci (vanA genotype: 16 Enterococcus faecalis, 1 Enterococcus faecium) were compared with 169 who had vancomycin-susceptible enterococcal bacteremia. The following were selected by multivariate analysis as independent risk factors that influenced the development of high-level vancomycin-resistant enterococcal bacteremia: prior glycopeptide therapy (P=0.049); inclusion in a hemodialysis program (P=0.046); prior therapy with corticosteroids or antineoplastic agents (P=0.029); and prior surgical treatment (P=0.022). The following other factors were selected by univariate analysis: tracheostomy (P=0.002); prolonged hospitalization (P=0.01); and any kind of puncture (P=0.02). The crude associated-mortality rate was 13.4%. Gene amplification of vanA was positive for 17 strains of enterococci. Pulsed-field gel electrophoresis of genomic DNA after SmaI digestion of vanA isolates revealed that one strain predominated (10 isolates), though at least four similar banding patterns were identified (6 isolates). The 16 strains closely related to the outbreak were investigated further. The surgical intensive care unit was the first and most involved service. The hospital outbreak of vanA vancomycin-resistant enterococcal bacteremia occurred between 1994 and 1995 and was caused by Enterococcus faecalis. This is believed to be the first and only such outbreak described in a Spanish hospital thus far.

[ROC curve analysis of factors predictive of non-response to interferon treatment in patients with chronic hepatitis C, genotype 1]

The objectives of this study included: 1) to identify pretreatment variables predictive of absence of response in 107 patients with chronic hepatitis C, genotype 1, treated with interferon-a (IFN-a) at a dose of 3 MU three times weekly for 3-12 months and classified into two groups: group A, nonresponders vs. patients with a complete response, and group B, nonresponding and relapsing patients vs. patients with a sustained response; and 2) to establish a prognostic index using ROC curve analysis. The rate of sustained response was 6. 5% at the 24-month follow-up. The pretreatment characteristics with predictive value using ROC curves were as follows: in group A, age, GGT, serum ferritin, viral load, and grade and stage of the histological lesion; and in group B, known duration of infection, GPT, GGT, serum ferritin, viral load, and grade and stage of the histological lesion. In both group A and group B the positive predictive value (the probability of predicting an absence of response when the variable is present) was greater than the negative predictive value (mean: 84.3% vs. 41.1%, 99% vs. 16.5%, respectively). In group A, based on the prognostic index, the positive predictive value when three variables were present was 96% and the sensitivity was 63.5%, with the test being unequivocal in 6.5%, whereas when four or five variables were present, the positive predictive value was 97% and 100% and the sensitivity was 40.5% and 18%, respectively. In group B, the positive predictive value when two variables were present was 100% and the sensitivity was 87%, whereas when three, four, five and six variables were present the sensitivity was between 73% and 28%. In group A, age, GGT and ferritin were the predictive variables independently associated with an absence of response, with a relative risk of 6.5, 4.8 and 3.1, respectively, whereas in group B we did not find variables independently associated with an absence of response. It was concluded that in patients with genotype 1, it is possible to predict the absence of response to IFN therapy with a high degree of reliability.

[Comparative analysis of viral load by bDNA HCV RNA-2.0 and amplicor HCV monitor in patients with hepatitis C infection]

BACKGROUND

Two standardized techniques, Quantiplex (bDNA-2.0) and Amplicor Monitor have been evaluated for the quantification of virus load of HCV with these objectives: a) determinate the relationship between virus load and genotype, and b) evaluate the virus load in serial serum samples and in patients with normal or slightly increased liver enzymes in an area with a high prevalence of genotype 1.

RESULTS

A significant correlation of 0.7 (p < 0.0001) in virus load has been observed by both methods, but the virus load is smaller by Monitor than by Quantiplex and does not depend on genotype. The relationship Monitor/Quantiplex is smaller in patients with non-1 genotype than in patients with genotype 1a (p = 0.01) and 1b (p = 0.005). Virus characteristics are similar in patients with normal or slightly increased enzymes than in patients with high enzymes. Virus load by both methods is not related to the age, sex, know duration of the infection, transmission manner of the infection neither to the histologic activity index.

CONCLUSION

The virus load not depends on genotype. The determination of virus load in a single serum sample adequately reflects the virus load are in several serum samples in patients with chronic HCV infection. The genotype and the virus load are similar in patients with normal enzymes than in patients with high enzymes.

[Neonatal colonization by Ureaplasma urealyticum and the development of bronchopulmonary dysplasia]

OBJECTIVE

The study purpose was to investigate the association between neonatal Ureaplasma urealyticum isolation, and bronchopulmonary dysplasia (BDP), in infants who had birth weights < 1,500 g, admitted in the Pediatric Intensive Care Unit, La Fe Hospital, Valencia, Spain.

METHODS

A cohort study was designed, since March 1996 until April 1998, with a cohort of exposed and no exposed, determined by isolation of U. urealyticum in tracheal aspirate or pharyngeal cultures. 137 infants were admitted to the intensive care unit in this period, and 101 of them were enrolled in this study.

RESULTS

U. urealyticum was isolated in 27 (26.7%) patients. The infants with U. urealyticum positive culture had a significantly lower gestational age (mean 28.1, SD 2.4 vs 29.2, SD 2.4; p = 0.048) than negative culture infants. BDP occurred in 30 infants (29.7%), and was significantly associated with decreasing gestational age (mean 26.9, SD 1.7 vs 29.7, SD 2.2; p < 0.001) and lower birth weight (mean 965.8, SD 166.7 vs 1121.4, SD 232.1; p < 0.001). However, after correction for gestational age by logistic regression analysis, DBP was significantly related to decreasing gestational age, but not to the presence of a positive U. urealyticum culture. In the cohort of U. urealyticum positive infants, BPD occurred in 9 (33%) vs 21 (28%) in the not colonized cohort. The odds ratio associated with colonization was 1.3 (CI 95% 0.5-3.2; p = 0.63).

CONCLUSIONS

BPD was significantly associated with decreasing gestational age, independently of birth weight and U. urealyticum colonization.