Drug-resistance mutations in antiretroviral-naive patients with established HIV-1 infection in Mexico

OBJECTIVES

To describe the prevalence of baseline drug-resistance mutations, resistance to antiretroviral drugs, and the subsequent virological response to therapy in treatment-naïve patients from Mexico with established HIV-1 infection.

METHODS

Resistance testing was performed on plasma samples from antiretroviral-naïve patients. Data on mutations associated with antiretroviral drug resistance were obtained using Stanford software (http://hivdb.stanford.edu).

RESULTS

Ninety-six treatment-naïve individuals were enrolled in the study during 2002-2003. Of these, 83 patients (86%) had at least one resistance mutation and 15 (16%) had drug resistance. At baseline, the mean plasma viral load was 299 834 HIV-1 RNA copies/mL, and at follow-up it was 37 620 copies/mL (P<0.0001). Primary mutations in the reverse transcriptase region were observed in 15% of patients. For nucleoside inhibitors, mutations T215Y/C and F77L (3%) and D67N/S, T69N and M184V (2%), were detected. For nonnucleoside inhibitors, mutations K103N/R (6%), Y181C (3%) and G190A (2%) were detected. Overall, 6% of patients showed resistance to delavirdine and nevirapine, 4% to efavirenz, and 2% to lamivudine and nelfinavir. Twelve patients showed no response to treatment and three of these patients had antiretroviral drug resistance.

CONCLUSIONS

The prevalence of baseline drug-resistance mutations found in this study was similar to that found in previous reports for newly HIV-infected individuals, although access to and management of antiretrovirals in Mexico are different.

Primary and acquired resistance of Mycobacterium tuberculosis in Western Mexico

Resistance of Mycobacterium tuberculosis to antimycobacterial agents is a worldwide problem. The proposite of this study was to analyze the current resistance patterns of patients with initial episodes, as well as relapses, due to M. tuberculosis in western Mexico. From January 1993 to February 1999 a total of 237 strains of M. tuberculosis (120 from initial cases and 117 from relapse cases) were analyzed. Two hundred and four (86%) strains were isolated from the lower respiratory tract, and 33 strains (14%) from extrapulmonary sites. Twenty-three percent of M. tuberculosis isolated from patients with initial episodes were resistant to both isoniazid and rifampin, and 52% of M. tuberculosis isolated from relapse cases were also resistant to both isoniazid and rifampin.

Asymptomatic bacteriuria and inflammatory response to urinary tract infection of elderly ambulatory women in nursing homes

BACKGROUND

Bacteriuria > or = 10(5) CFU/ml is evidence of urinary tract infection in the absence of associated signs or symptoms. The presence of pyuria with asymptomatic bacteriuria established the response of elderly women against microorganisms capable of causing invasiveness or tissue injury of the urinary tract.

METHODS

The association between bacteriuria and pyuria was determined in 178 elderly, ambulatory women without symptoms of urinary tract infection in seven nursing homes. Urine culture results were subsequently analyzed in conjunction with absolute leukocyte count in urine. In this cross-sectional study, asymptomatic bacteriuria in elderly women was classified with and without pyuria.

RESULTS

The prevalence of asymptomatic bacteriuria was found in 44 (24.7%) elderly women. The presence of pyuria had a sensitivity of 63.6% for bacteriuria and a specificity of 91%. The positive predictive value for the presence of pyuria predicting those with bacteriuria was 70%, and the negative predictive value for the absence of pyuria predicting those without bacteriuria was 88.4%. Escherichia coli was the most common organism isolated in 81.8% of the women.

CONCLUSIONS

Bacteriuria > or 10(5) CFU/ml associated with pyuria was detected in 77% of elderly women with asymptomatic urinary tract infections. Bacteriuria of < 10(5) CFU/ml with pyuria proves less sensitive as an indicator of urinary tract infection. Elderly women with pyuria but without bacteriuria should be studied for other causes of urinary tract inflammation.

Once-daily azithromycin in the treatment of adult skin and skin-structure infections

The aim of this prospective, blinded, randomized study was to demonstrate the efficacy and safety of oral azithromycin and dicloxacillin in the treatment of adults with acute skin and skin-structure infections. Sixty-two patients were included in the intent-to-treat group and 60 were evaluable for analysis. Azithromycin was given as a 500 mg once-daily dose for three days and dicloxacillin as 250 mg qid for seven days. Isolated pathogens included primarily Staphylococcus aureus, Streptococcus spp., and coagulase-negative staphylococci. Clinical resolution was 83.3% in the azithromycin group and 83.9% in the dicloxacillin group, with bacteriological eradication of 90.0% in the azithromycin group and 87.1% in the dicloxacillin group. Persistence of infection was recorded in one patient in the dicloxacillin group and superinfection in one patient in the azithromycin group. Azithromycin appears to be a safe and effective antibiotic for the treatment of adult patients with acute skin and skin-structure infections.

Quinolones in the treatment of Salmonella carriers

Infections caused by Salmonella typhi are commonly followed by a chronic carrier state despite positive clinical and initial bacteriologic responses. The use of primary antibiotics like chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole has several major drawbacks, including in some instances the failure to prevent the carrier state. The appearance worldwide of strains with multiple resistance to the most commonly used regimens has prompted the search for new forms of therapy. Among the agents studied have been third-generation cephalosporins and quinolones, which are active in vitro against bacterial enteropathogens like S. typhi. Resolution of chronic carriage of S. typhi and other salmonellae is difficult, and regimens commonly fail (including those that combine antibiotic administration with removal of the gallbladder). In addition to being active in vitro against Salmonella species, the newer quinolones adequately penetrate the intestinal lumen, liver, bile, and gallbladder. Initial experience with norfloxacin and ciprofloxacin in oral treatment of the chronic S. typhi carrier state in adults has been promising.