Results from the Survey of Antibiotic Resistance (SOAR) 2015-17 in Latin America (Argentina, Chile and Costa Rica): data based on CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints.

OBJECTIVES: To determine antibiotic susceptibility of Streptococcus pneumoniae and Haemophilus influenzae isolates from community-acquired respiratory tract infections (CA-RTIs) collected in 2015-17 from Argentina, Chile and Costa Rica. METHODS: MICs were determined by CLSI broth microdilution and susceptibility was assessed using CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints. RESULTS: A total of 170 S. pneumoniae and 218 H. influenzae isolates were collected at five centres in Argentina, Chile and Costa Rica in 2015-17. Small S. pneumoniae isolate numbers from Costa Rica (n = 2) meant that these could only be included in the penicillin susceptibility analysis; they were excluded from further country analyses. Around one-third of pneumococcal isolates from Argentina and two-thirds from Chile were non-susceptible to penicillin by CLSI oral or EUCAST low-dose IV breakpoints, but most (≥89%) were susceptible by CLSI IV or EUCAST high-dose breakpoints. Amongst pneumococci from Argentina, about 80% or more were susceptible to most other antibiotics except cefaclor (all breakpoints), cefixime (PK/PD breakpoints), cefuroxime (EUCAST breakpoints) and trimethoprim/sulfamethoxazole (CLSI and PK/PD breakpoints). S. pneumoniae isolates from Chile showed significantly lower susceptibility (P < 0.05) using CLSI breakpoints compared with those from Argentina for many of the antibiotics tested. Among isolates of H. influenzae from Latin America, more than 90% were susceptible to amoxicillin/clavulanic acid (high dose), cefixime, cefpodoxime, ceftriaxone and fluoroquinolones, irrespective of the breakpoints used. The application of different EUCAST breakpoints for low and higher doses for some of the antibiotics (amoxicillin, amoxicillin/clavulanic acid, ampicillin, penicillin, ceftriaxone, clarithromycin, erythromycin, levofloxacin and trimethoprim/sulfamethoxazole) allowed, for the first time in a SOAR study, the effect of raising the dosage on susceptibility to be quantified. CONCLUSIONS: Antibiotic susceptibility of H. influenzae isolates was generally high in the Latin American countries studied; however, susceptibility profiles varied for S. pneumoniae by country and depending on the breakpoints used, especially for cefaclor. These factors are important in decision making for empirical therapy of bacterial infections.

Oropharyngeal candidosis in AIDS patients: an epidemiological study using restriction analysis of Candida albicans total genomic DNA.

This study investigates the epidemiology of Candida albicans strains isolated from oral and rectal swabs obtained before and after treatment with antifungal drugs in hospitalized AIDS patients. Twenty-one health care workers from the hospital unit were also studied. Samples were obtained from the oral cavity and hands. The molecular fingerprinting restriction endonuclease-digested genomic DNA technique was used. A total of 94 C. albicans strains were isolated: 76 from patients and 18 from the health care workers. Each sample was digested independently with EcoRI and HinfI restriction enzymes, electrophoresed on 0.8% agarose gels and stained with ethidium bromide. The strains were sorted into groups according to patterns. Analysis of the different restriction patterns suggests that most of the infective strains had an endogenous source, whereas the recurrences of candidosis, after antifungal therapy, could be considered as persistence or reinfection by a different strain. Our data show that horizontal transmission by strains carried by health care workers does not play an important role in the overall epidemiology of candidosis.