Pharmacogenetic Associations Between Atazanavir/UGT1A1*28 and Efavirenz/rs3745274 (CYP2B6) Account for Specific Adverse Reactions in Chilean Patients Undergoing Antiretroviral Therapy

Background: Efavirenz (EFV), a non-nucleoside reverse transcriptase inhibitor, and atazanavir (ATV), a protease inhibitor, are drugs widely used in antiretroviral therapy (ART) for people living with HIV. These drugs have shown high interindividual variability in adverse drug reactions (ADRs). UGT1A1*28 and CYP2B6 c.516G>T have been proposed to be related with higher toxicity by ATV and EFV, respectively.

Objective: To study the association between genetic polymorphisms and ADRs related to EFV or ATV in patients living with HIV treated at a public hospital in Chile.

Methods: Epidemiologic, case–control, retrospective, observational study in 67 adult patients under EFV or ATV treatment was conducted, in the San Juan de Dios Hospital. Data were obtained from patients’ medical records. Genotype analyses were performed using rtPCR for rs887829 (indirect identification of UGT1A1*28 allele) and rs3745274 (CYP2B6 c.516G>T), with TaqMan® probes. The association analyses were performed with univariate logistic regression between genetic variants using three inheritance models (codominant, recessive, and dominant).

Results: In ATV-treated patients, hyperbilirubinemia (total bilirubin >1.2 mg/dl) had the main incidence (61.11%), and moderate and severe hyperbilirubinemia (total bilirubin >1.9 mg/dl) were statistically associated with UGT1A1*28 in recessive and codominant inheritance models (OR = 16.33, p = 0.028 and OR = 10.82, p = 0.036, respectively). On the other hand, in EFV-treated patients adverse reactions associated with CNS toxicity reached 34.21%. In this respect, nightmares showed significant association with CYP2B6 c.516G>T, in codominant and recessive inheritance models (OR = 12.00, p = 0.031 and OR = 7.14, p = 0.042, respectively). Grouped CNS ADRs (nightmares, insomnia, anxiety, and suicide attempt) also showed a statistically significant association with CYP2B6 c.516G > T in the codominant and recessive models (OR = 30.00, p = 0.011 and OR = 14.99, p = 0.021, respectively).

Conclusion: Our findings suggest that after treatment with ATV or EFV, UGT1A1*28 and CYP2B6 c.516G>T influence the appearance of moderate-to-severe hyperbilirubinemia and CNS toxicity, respectively. However, larger prospective studies will be necessary to validate these associations in our population. Without a doubt, improving adherence in patients living with HIV is a critical issue to the success of therapy. Hence, validating and applying international pharmacogenetic recommendations in Latin American countries would improve the precision of ART: a fundamental aspect to achieve the 95–95–95 treatment target proposed by UNAIDS.

[Nocardia cyriacigeorgica infection in AIDS patient]

Nocardiosis is a localized or systemic infection that mainly affects immunocompromised patients, with pulmonary localization being the most frequent site. The transmission comes mainly from the inhalation of spores or by direct inoculation into the skin and ocular mucosa. More than 90 species of nocardia are described, of which more than half are recognized as pathogens in humans. The best known species of medical importance are Nocardia farcinica, Nocardia abscessus, Nocardia nova y Nocardia brasiliensis. In Chile, there have been published cases of Nocardia asteroides and Nocardia farcinica infections. Nocardia cyriacigeorgica is considered an emerging species, there being no cases previously described in our country. We present a clinical case of pulmonary nocardiosis in an acquired immunodeficiency syndrome (AIDS) patient.

[Campylobacter jejuni bacteremia in a patient with HIV infection in AIDS stage]

Bacteremia is an atypical presentation of Campylobacter jejuni infection and it is more frequent in patients with advanced inmunodepression due to HIV or other sistemic diseases. Because of the highly active antiretroviral therapy, in the last decades the number of cases had declined. We report a case of a homeless woman with HIV in C3 stage who was diagnosed with the bacteremia during her hospitalization for pulmonary tuberculosis, and a brief review of C. jejuni bacteremia in HIV patients.

[Clinical utility of HIV viral load assessment in cerebral spinal fluid, a case report]

Detection of virus in cerebrospinal fluid (CSF) in HIV-infected patients with HIV viral load (VL) undetectable in plasma has been termed viral escape. These leaks may be asymptomatic from a neurological point of view, similar to plasma blips, or associated with neurological disease, with discordant VL between plasma and CSF, and may be evidence of a compartmentalization of the virus and the possibility of identifying quasispecies with mutations that confer resistance to ART. We present the case of a man with AIDS and disseminated tuberculosis who presented neurological symptomatology evidenced by headache and convulsive syndrome, who presented a discordance between plasma and CSF HIV VL; the genotypic test of the virus, obtained by lumbar puncture, identified new mutations that determined a change in ART with subsequent satisfactory evolution.

[Daptomycin: pharmacological characteristics and its role in the treatment of gram positive infections]

Daptomycin recently made available in Chile, belongs to a new family of antimicrobials known as lypopeptides. Daptomycin has a unique mechanism of action and a potent bactericidal activity over susceptible agents. It is active against a number of clinically significant Gram positive cocci, including strains of Staphylococcus aureus and Enterococcus spp., both susceptible and resistant to classic antimicrobials. Daptomycin has been approved for clinical use in skin and soft tissue infections, and for S. aureus bacteremia in adult patients. Ongoing trials suggest that daptomycin is also useful in the treatment of other infections such as osteomyelitis, biofilm producing infections, and in immunocompromised patients, particularly onco-hematologic patients. The main adverse reaction associated with daptomycin use is myopathy, usually mild and reversible.

Rapid molecular detection of pulmonary tuberculosis in HIV-infected patients in Santiago, Chile

SETTING

Santiago, Chile, has a mean annual tuberculosis (TB) rate of 13 per 100 000 population; however, TB incidence in human immunodeficiency virus (HIV) infected individuals is at least 20 times higher.

OBJECTIVE

To assess the accuracy of rapid molecular testing for pulmonary TB (PTB) detection in routine care in HIV-infected patients.

DESIGN

Cross-sectional study, conducted prospectively in five hospitals between March 2010 and June 2011. HIV-positive subjects with suspected PTB provided sputum or mouth wash samples that were directly processed for acid-fast smear, mycobacterial cultures and Xpert® MTB/RIF. Positive test results were reported on the same day.

RESULTS

We enrolled 166 subjects into the study; 50.6% provided two sputum samples, 33.1% only one sputum sample and 16.3% a mouth wash sample. The prevalence of TB was 8.1% (13/160). Diagnostic sensitivity increased from 66.7% (95%CI 39.1-86.2) for acid-fast smear to 91.7% (95%CI 64.6-98.5) for Xpert MTB/RIF, with comparable specificity at 98.6% (146/148, 95%CI 95.2-99.6) and 99.3% (147/148, 95%CI 96.3-99.9). Xpert MTB/RIF allowed early detection of rifampicin resistance in 16.6% of cases, with rapid adjustment to multidrug-resistant treatment.

CONCLUSION

Xpert MTB/RIF provided earlier TB diagnosis in 25% more cases than acid-fast smear alone. Its implementation should be considered for TB diagnosis in HIV-positive patients even outside TB-endemic areas.

[Scedosporium apiospermum rhinosinusal infection in an immunocompetent host]

Scedosporium species can cause colonization, superficial and deep localized infection or systemic disease, especially in immunocompromised hosts. We report a case of localized infection due to Scedosporium apiospermum in a 47 year old woman, with previous nasal surgery. She consulted for recurrent mucopurulent post-nasal discharge not responding to antibiotics. Computed tomography showed opacification of right maxillary sinus. Surgery was performed to removed abnormal tissue from sinus; biopsy revealed chronic sinusitis with aggregate of tightly packed hyphae suggestive of filamentous fungi. The microbiology fungal culture reported Scedosporium apiospermum.

[Presence of Bartonella henselae in cats: natural reservoir quantification and human exposition risk of this zoonoses in Chile]

BACKGROUND

The availability of a serologic test for cat scratch disease in humans has allowed the diagnosis of an increasing number of cases of this disease in Chile.

AIM

To perform a serological survey for Bartonella henselae among cats in Chile.

MATERIAL AND METHODS

Blood samples from 187 cats living in three Chilean cities were obtained. IgG antibodies against Bartonella henselae were measured using indirect immunofluorescence. Blood cultures were done in 60 samples. The presence of Bartonella henselae in positive cultures was confirmed by restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR).

RESULTS

The general prevalence of IgG antibodies against Bartonella henselae was 85.6%. No differences in this prevalence were found among cats younger or older than 1 year, or those infested or not infested with fleas. However domestic cats had a lower prevalence when compared with stray cats (73 and 90% respectively, p <0.01). Bartonella henselae was isolated in 41% of blood cultures. All the isolated were confirmed as Bartonella henselae by RFLP-PCR.

CONCLUSIONS

This study found an important reservoir of Bartonella henselae in Chilean cats and therefore a high risk of exposure in humans who have contact with them.

[Utility of stool culture in inpatient]

Several studies have concluded that it is inappropriate to perform stool cultures (SC) to inpatients that have stayed hospitalized three days or more because nosocomial diarrhea is not due to enteric pathogenic bacteria that are searched through this exam. The aim of this paper was to analyze the SC yield performed to patients hospitalized in the UC Health Net since January to December 2002 and the rate of positive results obtained depending on the length of hospitalization in order to define if international guidelines are useful to the national reality. During twelve months 3474 SC were evaluated, 458 (13.2%) belonged to inpatients. Of them 16 (3.5%) were positive, 13 were obtained on the first day, 2 at the second day and 1 at the fifth day of hospitalization. Only 1/190 (0.5) SC obtained after two days of hospitalization yielded a positive result. These results reinforce the international recommendation of not performing SC to inpatients that have stayed more than three days at the hospital; besides, considering previous figures, we suggest to make a cutoff at day two of hospitalization, after two days there is no a significant clinical impact. This strategy means to reduce 41% of these analyses and to save the corresponding money.

[Toxocariasis in an adult manifested as hypereosinophilic syndrome with predominant neurological involvement. Clinical case]

Hypereosinophilic syndrome is characterized by persistent hypereosinophilia and signs or symptoms due to organ involvement, specially nervous system, heart and skin. It can be primary or secondary to allergies, parasites or cancer. Toxocariasis is an uncommon parasitic disease in adults. There is a variant, called visceral larva migrans, that can involve different organs, and among those, the central nervous system. We report a 61 years old male, with a cerebrovascular disease. There were focalizing symptoms, the CAT scan showed multiple ischemic lesions and a peripheral eosinophilia of 12,152 cells/mm3 was present. Anti toxocara IgG antibody titers were 1/1000. The patient was treated with albendazole for 14 days. After a 2 years follow up the patients is in good conditions and, for the first time, his eosinophil count is within normal limits.