BMC Infectious Diseases - Latest Articles

Performance of the tuberculin skin test and interferon-gamma release assay for detection of tuberculosis infection in immunocompromised patients in a BCG-vaccinated population

Eun Young Kim — 2009-12-15T00:00:00Z

Background: Interferon-gamma release assay (IGRA) may improve diagnostic accuracy for latent tuberculosis infection (LTBI). This study compared the performance of the tuberculin skin test (TST) with that of IGRA for the diagnosis of LTBI in immunocompromised patients in an intermediate TB burden country where BCG vaccination is mandatory. Methods: We conducted a retrospective observational study of patients given the TST and an IGRA, the QuantiFERON-TB Gold In-Tube (QFT-IT), at Severance Hospital, a tertiary hospital in South Korea, from December 2006 to May 2009. Results: Of 211 patients who underwent TST and QFT-IT testing, 117 (55%) were classified as immunocompromised. Significantly fewer immunocompromised than immunocompetent patients had positive TST results (10.3% vs. 27.7%, p 0.001), whereas the percentage of positive QFT-IT results was comparable for both groups (21.4% vs. 25.5%). However, indeterminate QFT-IT results were more frequent in immunocompromised than immunocompetent patients (21.4% vs. 9.6%, p 0.021). Agreement between the TST and QFT-IT was fair for the immunocompromised group (kappa = 0.38), but moderate agreement was observed for the immunocompetent group (kappa = 0.57). Indeterminate QFT-IT results were associated with anaemia, lymphocytopenia, hypoproteinemia, and hypoalbuminemia. Conclusion: In immunocompromised patients, the QFT-IT may be more sensitive than the TST for detection of LTBI, but it resulted in a considerable proportion of indeterminate results. Therefore, both tests may maximise the efficacy of screening for LTBI in immunocompromised patients.

Severity of Giardia infection associated with post-infectious fatigue and abdominal symptoms two years after

Kristine Morch — 2009-12-15T00:00:00Z

Background: A high rate of post-infectious fatigue and abdominal symptoms two years after a waterborne outbreak of giardiasis in Bergen, Norway in 2004 has previously been reported. The aim of this report was to identify risk factors associated with such manifestations. Methods: All laboratory confirmed cases of giardiasis (n = 1262) during the outbreak in Bergen in 2004 received a postal questionnaire two years after. Degree of post-infectious abdominal symptoms and fatigue, as well as previous abdominal problems, was recorded. In the statistical analyses number of treatment courses, treatment refractory infection, delayed education and sick leave were used as indices of protracted and severe Giardia infection. Age, gender, previous abdominal problems and symptoms during infection were also analysed as possible risk factors. Simple and multiple ordinal logistic regression models were used for the analyses. Results: The response rate was 81 % (1017/1262), 64% were women and median age was 31 years (range 3-93), compared to 61% women and 30 years (range 2-93) among all 1262 cases. Factors in multiple regression analysis significantly associated with abdominal symptoms two years after infection were: More than one treatment course, treatment refractory infection, delayed education, bloating and female gender. Abdominal problems prior to Giardia infection were not associated with post-infectious abdominal symptoms. More than one treatment course, delayed education, sick leave more than 2 weeks, and malaise at the time of infection, were significantly associated with fatigue in the multiple regression analysis, as were increasing age and previous abdominal problems. Conclusion: Protracted and severe Giardia infection seemed to be a risk factor for post-infectious fatigue and abdominal symptoms two years after the infection had been cleared.

Early severe morbidity and resource utilization in South African adults on antiretroviral therapy

Teresa Smith de Cherif — 2009-12-15T00:00:00Z

Background: High rates of mortality and morbidity have been described in sub-Saharan African patients within the first few months of starting highly active antiretroviral therapy (HAART). There is limited data on the causes of early morbidity on HAART and the associated resource utilization. Methods: A cross-sectional study was conducted of medical admissions at a secondary-level hospital in Cape Town, South Africa. Patients on HAART were identified from a register and HIV-infected patients not on HAART were matched by gender, month of admission, and age group to correspond with the first admission of each case. Primary reasons for admission were determined by chart review. Direct health care costs were determined from the provider's perspective. Results: There were 53 in the HAART group with 70 admissions and 53 in the no-HAART group with 60 admissions. The median duration of HAART was 1 month (interquartile range 1-3 months). Median baseline CD4 count in the HAART group was 57 x 106 cells/L (IQR 15-115). The primary reasons for admission in the HAART group were more likely to be due to adverse drug reactions and less likely to be due to AIDS events than the no-HAART group (34% versus 7%; p<0.001 and 39% versus 63%; p=0.005 respectively). Immune reconstitution inflammatory syndrome was the primary reason for admission in 10% of the HAART group. Lengths of hospital stay per admission and inpatient survival were not significantly different between the two groups. Five of the 15 deaths in the HAART group were due to IRIS or adverse drug reactions. Median costs per admission of diagnostic and therapeutic services (laboratory investigations, radiology, intravenous fluids and blood, and non-ART medications) were higher in the HAART group compared with the no-HAART group (US$190 versus US$111; p=0.001), but the more expensive non-curative costs (overhead, capital, and clinical staff) were not significantly different (US$1199 versus US$1128; p=0.525). Conclusions: Causes of early morbidity are different and more complex in HIV-infected patients on HAART. This results in greater resource utilization of diagnostic and therapeutic services.

A changing picture of shigellosis in Southern Vietnam; shifting species dominance, antimicrobial susceptibility and clinical presentation

Ha Vinh — 2009-12-15T00:00:00Z

Background: Shigellosis remains considerable public health problem in some developing countries. The nature of Shigellae suggests that they are highly adaptable when placed under selective pressure in a human population. This is demonstrated by variation and fluctuations in serotypes and antimicrobial resistance profile of organisms circulating in differing setting in endemic locations. Antimicrobial resistance in Shigellae is a constant threat, with reports of organisms in Asia being resistant to multiple antimicrobials and new generation therapies. Methods: Here we compare microbiological, clinical and epidemiological data from patients with shigellosis over three different periods in Southern Vietnam spanning14 years. Results: Our data demonstrates a shift in dominant infecting species (S. flexneri to S. sonnei) and resistance profile of the organisms circulating in Southern Vietnam. We find that there was no significant variation in the syndromes associated with either S. sonnei or S. flexneri, yet the clinical features of the disease are more severe in later observations. Conclusions: Our findings show a change in clinical presentation of shigellosis in this setting, as the disease may be now more pronounced, this is concurrent with a change in antimicrobial resistance profile. These data highlight the socio-economic development of Southern Vietnam and should guide future vaccine development and deployment strategies.Trial Registration Current Controlled Trials ISRCTN55945881

Hepatic profile analyses of tipranavir in Phase II and III clinical trials

Jaromir Mikl — 2009-12-14T00:00:00Z

Background: The risk and course of serum transaminase elevations (TEs) and clinical hepatic serious adverse event (SAE) development in ritonavir-boosted tipranavir (TPV/r) 500/200mg BID recipients, who also received additional combination antiretroviral treatment agents in clinical trials (TPV/r-based cART), was determined. Methods: Aggregated transaminase and hepatic SAE data through 96 weeks of TPV/r-based cART from five Phase IIb/III trials were analyzed. Patients were categorized by the presence or absence of underlying liver disease (+LD or -LD). Kaplan-Meier (K-M) probability estimates for time-to-first US National Institutes of Health, Division of AIDS (DAIDS) Grade 3/4 TE and clinical hepatic SAE were determined and clinical actions/outcomes evaluated. Risk factors for DAIDS Grade 3/4 TE were identified through multivariate Cox regression statistical modeling. Results: Grade 3/4 TEs occurred in 144/1299 (11.1%) patients; 123/144 (85%) of these were asymptomatic; 84% of these patients only temporarily interrupted treatment or continued, with transaminase levels returning to Grade [less than or equal to]2. At 96 weeks of study treatment, the incidence of Grade 3/4 TEs was higher among the +LD (16.8%) than among the -LD (10.1%) patients. K-M analysis revealed an incremental risk for developing DAIDS Grade 3/4 TEs; risk was greatest through 24 weeks (6.1%), and decreasing thereafter (>24-48 weeks: 3.4%, >48 weeks-72 weeks: 2.0%, >72-96 weeks: 2.2%), and higher in +LD than -LD patients at each 24-week interval. Treatment with TPV/r, co-infection with hepatitis B and/or C, DAIDS grade >1 TE and CD4+ > 200 cells/mm3 at baseline were found to be independent risk factors for development of DAIDS Grade 3/4 TE; the hazard ratios (HR) were 2.8, 2.0, 2.1 and 1.5, respectively. Four of the 144 (2.7%) patients with Grade 3/4 TEs developed hepatic SAEs; overall, 14/1299 (1.1%) patients had hepatic SAEs including six with hepatic failure (0.5%). The K-M risk of developing hepatic SAEs through 96 weeks was 1.4%; highest risk was observed during the first 24 weeks and decreased thereafter; the risk was similar between +LD and -LD patients for the first 24 weeks (0.6% and 0.5%, respectively) and was higher for +LD patients, thereafter. Conclusion: Through 96 weeks of TPV/r-based cART, DAIDS Grade 3/4 TEs and hepatic SAEs occurred in approximately 11% and 1% of TPV/r patients, respectively; most (84%) had no significant clinical implications and were managed without permanent treatment discontinuation. Among the 14 patients with hepatic SAE, 6 experienced hepatic failure (0.5%); these patients had profound immunosuppression and the rate appears higher among hepatitis co-infected patients. The overall probability of experiencing a hepatic SAE in this patient cohort was 1.4% through 96 weeks of treatment. Independent risk factors for DAIDS Grade 3/4 TEs include TPV/r treatment, co-infection with hepatitis B and/or C, DAIDS grade >1 TE and CD4+ > 200 cells/mm3 at baseline.US-NIH Trial registration number: NCT00144170

The role of beta-lactamase-producing-bacteria in mixed infections

Itzhak Brook — 2009-12-14T00:00:00Z

Beta-lactamase-producing bacteria (BLPB) can play an important role in polymicrobial infections. They can have a direct pathogenic impact in causing the infection as well as an indirect effect through their ability to produce the enzyme beta-lactamase. BLPB may not only survive penicillin therapy but can also, as was demonstrated in in vitro and in vivo studies, protect other penicillin-susceptible bacteria from penicillin by releasing the free enzyme into their environment. This phenomenon occurs in upper respiratory tract, skin, soft tissue, surgical and other infections. The clinical, in vitro, and in vivo evidence supporting the role of these organisms in the increased failure rate of penicillin in eradication of these infections and the implication of that increased rate on the management of infections is discussed.

Association of HLA-A, B, DRB1 alleles and haplotypes with HIV-1 infection in Chongqing, China

Xia Huang — 2009-12-12T00:00:00Z

Background: The human immunodeficiency virus type 1(HIV-1) epidemic in Chongqing, China, is increasing rapidly with the dominant subtype of CRF07_BC over the past 3 years. Since human leukocyte antigen (HLA) polymorphisms have shown strong association with susceptibility/resistance to HIV-1 infection from individuals with different ethnic backgrounds, a recent investigation on frequencies of HLA class I and class II alleles in a Chinese cohort also indicated that similar correlation existed in HIV infected individuals from several provinces in China, however, such information is unavailable in Chongqing, southwest China. Methods: In this population-based study, we performed polymerase chain reaction analysis with sequence-specific oligonucleotide probes (PCR-SSOP) for intermediate-low-resolution HLA typing in a cohort of 549 HIV-1 infected individuals, another 2475 healthy subjects from the Han nationality in Chongqing, China, were selected as population control. We compared frequencies of HLA-A, B, DRB1 alleles, haplotypes and genotypes between the two groups, and analyzed their association with HIV-1 susceptibility or resistance. Results: The genetic profile of HLA (A, B, DRB1) alleles of HIV-1 infected individuals from Chongqing Han of China was obtained. Several alleles of HLA-B such as B*46 (P=0.001, OR=1.38, 95%CI=1.13-1.68), B*1501G(B62) (P=0.013, OR=1.42, 95%CI=1.08-1.88), B*67 (P=0.022, OR=2.76, 95%CI=1.16-6.57), B*37 (P=0.014, OR=1.93, 95%CI=1.14-3.28) and B*52 (P=0.038, OR=1.64, 95%CI=1.03-2.61) were observed to have association with susceptibility to HIV-1 infection in this population. In addition, the haplotype analysis revealed that A*11-B*46, A*24-B*54 and A*01-B*37 for 2-locus, and A*11-B*46-DRB1*09, A*02-B*46-DRB1*08, A*11-B*4001G-DRB1*15, A*02-B*4001G-DRB1*04, A*11-B*46-DRB1*08 and A*02-B*4001G-DRB1*12 for 3-locus had significantly overrepresented in HIV-1 infected individuals, whereas A*11-B*1502G, A*11-B*1502G-DRB1*12 and A*33-B*58-DRB1*13 were underrepresented. However, the low-resolution homozygosity of HLA-A, B, DRB1 loci and HLA-Bw4/Bw6 genotypes did not differ significantly between the two groups. Conclusion: These results may contribute to the database of HLA profiles in HIV-1 infected Chinese population, consequently, the association of certain HLA alleles with susceptibility or resistance to HIV-1 infection would provide with clues in choosing proper preventive strategies against HIV-1 infection and developing effective HIV-1 vaccines in Chinese population, especially for those in southwest China.

Destructive arthritis in a patient with chikungunya virus infection with persistent specific IgM antibodies

Denis Malvy — 2009-12-10T00:00:00Z

Background: Chikungunya fever is an emerging arboviral disease characterized by an algo-eruptive syndrome, inflammatory polyarthralgias, or tenosynovitis that can last for months to years. Up to now, the pathophysiology of the chronic stage is poorly understood.Case presentationWe report the first case of CHIKV infection with chronic associated rheumatism in a patient who developed progressive erosive arthritis with expression of inflammatory mediators and persistence of specific IgM antibodies over 24 months following infection. Conclusions: Understanding the specific features of chikungunya virus as well as how the virus interacts with its host are essential for the prevention, treatment or cure of chikungunya disease.

Cryptic Leishmania infantum infection in Italian HIV infected patients

Claudia Colomba — 2009-12-10T00:00:00Z

Background: Visceral leishmaniasis (VL) is a protozoan diseases caused in Europe by Leishmania (L.) infantum. Asymptomatic Leishmania infection is more frequent than clinically apparent disease. Among HIV infected patients the risk of clinical VL is increased due to immunosuppression, which can reactivate a latent infection. The aims of our study were to assess the prevalence of asymptomatic L. infantum infection in HIV infected patients and to study a possible correlation between Leishmania parasitemia and HIV infection markers. Methods: One hundred and forty-five HIV infected patients were screened for the presence of anti-Leishmania antibodies and L. infantum DNA in peripheral blood. Statistical analysis was carried out by using a univariate regression analysis. Results: Antibodies to L. infantum were detected in 1.4% of patients. L. infantum DNA was detected in 16.5% of patients. Significant association for PCR-Leishmania levels with plasma viral load was documented (p=0.0001). Conclusions: In our area a considerable proportion of HIV infected patients are asymptomatic carriers of L. infantum infection. A relationship between high HIV viral load and high parasitemic burden, possibly related to a higher risk of developing symptomatic disease, is suggested. PCR could be used for periodic screening of HIV patients to individuate those with higher risk of reactivation of L. infantum infection.

Combination antiretroviral drugs in PLGA nanoparticle for HIV-1

Christopher Destache — 2009-12-09T00:00:00Z

Background: Combination antiretroviral (AR) therapy continues to be the mainstay for HIV treatment. However, antiretroviral drug nonadherence can lead to the development of resistance and treatment failure. We have designed nanoparticles (NP) that contain three AR drugs and characterized the size, shape, and surface charge. Additionally, we investigated the in vitro release of the AR drugs from the NP using peripheral blood mononuclear cells (PBMCs). Methods: Poly-(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) containing ritonavir (RTV), lopinavir (LPV), and efavirenz (EFV) were fabricated using multiple emulsion-solvent evaporation procedure. The nanoparticles were characterized by electron microscopy and zeta potential for size, shape, and charge. The intracellular concentration of AR drugs was determined over 28 days from NPs incubated with PBMCs. Macrophages were imaged by fluorescent microscopy and flow cytometry after incubation with fluorescent NPs. Finally, macrophage cytotoxicity was determined by MTT assay. Results: Nanoparticle size averaged 262 + 83.9 nm and zeta potential -11.4 + 2.4. AR loading averaged 4% (w/v). Antiretroviral drug levels were determined in PBMCs after 100 mcg of NP in 75 mcL PBS was added to media. Intracellular peak AR levels from NPs (day 4) were RTV 2.5 + 1.1; LPV 4.1 + 2.0; and EFV 10.6 + 2.7 mcg and continued until day 28 (all AR > 0.9 mcg). Free drugs (25 mcg of each drug in 25 mcL ethanol) added to PBMCs served as control were eliminated by 2 days. Fluorescence microscopy and flow cytometry demonstrated phagocytosis of NP into monocytes-derived macrophages (MDMs). Cellular MTT assay performed on MDMs demonstrated that NPs are not significantly cytotoxic. Conclusions: These results demonstrated AR NPs could be fabricated containing three antiretroviral drugs (RTV, LPV, EFV). Sustained release of AR from PLGA NP show high drug levels in PBMCs until day 28 without cytotoxicity.