[Enzymatic mechanisms of resistance to aminoglycoside antibiotics in gram negative bacilli from Chilean hospitals]. / Mecanismos enzimáticos de resistencia a antibióticos aminoglicósidos en bacilos gram negativos de hospitales chilenos.

The presence of aminoglycoside modifying enzymes (AMEs) has been investigated, by an agar diffusion method, in 344 strains of aminoglycoside-resistant Gram negative bacilli isolated in different Chilean hospitals. Most of the strains exhibited a combination of enzymatic mechanism of resistance, but two acetylating (AAC(3)II and AAC(6')I) and one phosphorylating (APH(3')I) enzymes were the main mechanism detected in the strains. A significant increase in the frequency of strains producing AAC(6')I, possible due to wide use of amikacin, has been found when results were compared with those of a report published in 1985.

A diallel analysis of gregarious oviposition in Drosophila melanogaster.

Drosophila females exhibit gregarious oviposition. This behaviour was analysed by a diallel cross. The trait shows considerable additive genetic variation and a significant dominant effect. A variance and covariance analysis suggests that ebony and taxi strains contain the most dominant alleles. Some maternal effect may also be present. This genetical architecture is in line with previous studies of selection and hybridization of the lines selected for high and low gregarious oviposition in Drosophila melanogaster females.

Herpes simplex virus and cytomegalovirus in pregnant Chilean university students.

Virus isolation tests were performed during the first, second, and third trimesters of pregnancy on a group of 163 students who received prenatal care at the University of Chile's Student Medical and Dental Service to determine the possible existence of genital herpes or cytomegalovirus infections. Vaginal secretion samples tested for herpes simplex virus (HSV) and urine samples tested for cytomegalovirus (CMV) were inoculated onto cell cultures and examined by immunofluorescent procedures using monoclonal antibodies. HSV was detected in five subjects, only one of whom had herpetic lesions, and was identified as type 2 in all cases. Cytomegalovirus was detected in seven subjects.

[Herpes simplex virus and cytomegalovirus in pregnant Chilean university students]. / Virus del herpes simple y citomegalovirus en universitarias chilenas embarazadas.

Virus isolation tests were performed on a group of 163 students who received prenatal care at the Student Medical and Dental Service at the University of Chile (Santiago) during the 1st, 2nd, and 3rd trimesters of pregnancy to determine the possible existence of genital herpes infection (isolation from vaginal secretions) or cytomegalovirus infection (isolation from urine). The samples were inoculated on cell cultures and were then studied using immunofluorescence with monoclonal antibodies. The herpes simplex virus (HSV) was detected in the vaginal secretions of 5 pregnant women, only one of whom had herpes lesions; in all these cases, the virus isolated was HSV type 2. Cytomegalovirus was detected in 7 of the pregnant women.

[Characteristics of herpes genitalis in university women]. / Características del herpes genital en mujeres universitarias.

We analyzed 33 patients with herpes genitalis diagnosed at a student medical outpatient facility. 42% corresponded to a first herpetic infection. The HSV-1 was present in 43% of cases, the HSV-2 in the rest. Recurrence of infection was present in 39.5% of patients, 70% of them due to HSV-2. There was a relatively high rate of asymptomatic couples who were the source of primary herpetic infection.

[A combination of ampicillin and sulbactam: effect on aerobic and anaerobic gram-negative bacteria]. / Asociación ampicilina y sulbactam: actividad sobre bacilos gram negativos aerobios y anaerobios.

The antibacterial activity of the association of ampicillin and sulbactam (2:1) upon strains of aerobic and anaerobic Gram negative agents was assayed. Inhibition of B-lactamases from intact and disrupted cells of some selected strains by sulbactam was also determined. Susceptibility was found in 34% and partial inhibition in 48%; 18% were fully resistant. Synergy between ampicillin and sulbactam was found upon ampicillin susceptible strains. This effect might reflect higher degree of binding of the inhibitor to PBP's in the absence of a trapping effect produced by B-lactamases. Anaerobic microorganisms were found to be highly susceptible to this association of B-lactams. Adequate penetration of the inhibitor into periplasmic space of Gram negative bacilli was deduced by the similar decrease of B-lactamase activity observed in intact and disrupted cells treated with sulbactam.

[Genital herpes infection in Chilean female university students]. / Infección genital herpética en estudiantes universitarias Chilenas.

This article reports on the prevalence of genital herpes infection in a sample of 635 female university students who were seen at the Gynecology Center of the University of Chile Student Medical Service. Viral isolation of genital secretions yielded 18 students (2.8%) with positive results, of whom 28% were asymptomatic shedders. Of the positive cases, 61% were clinically classified as recurrent and 39% as first episodes of genital herpes. Fluorescent monoclonal antibody typing of the isolated strains revealed that 72% were herpes simplex type 2 and 28% were type 1. The results confirm the importance of type 2 virus in genital herpes infections. They also point to asymptomatic shedders as a potential source of infection, and show the importance of a history of genital herpes in the identification of this population.

Bacteriological studies with ampicillin/sulbactam on selected strains of gram-negative bacteria.

Antibacterial activity of sulbactam or ampicillin alone and in combination on ampicillin-resistant, beta-lactamase-producing Gram-negative bacteria (Citrobacter freundii and Escherichia coli) was studied. Inhibition of beta-lactamase activity by sulbactam was investigated using intact and disrupted cells. Minimal inhibitory concentrations of ampicillin were high but decreased significantly in the presence of sulbactam. Similar enzyme inhibition was observed with intact and disrupted bacterial cells, thus indicating efficient penetration by sulbactam into the periplasmic space. Bacterial killing was achieved in approximately 4 hrs with ampicillin/sulbactam at concentrations that neither killed nor inhibited the same strains when the drugs were used alone. Sulbactam was more effective against plasmid-cured strain of E. coli than the same plasmid-containing organism.

[Moraxella osloensis as pathogen in septicemia (author's transl)]. / Moraxella osloensis als Sepsis-Erreger

A case of septicemia caused by Moraxella osloensis is described. A 4-year old girl fell ill with symptoms similar to those described in cases of septicemia caused by Neisseria meningitidis. Two days after the commencement of treatment with penicillins, however, Moraxella osloensis could be isolated from cerebral fluid, which contained only a small number of cells. It is assumed that the delayed recovery of the child was directly related to the diminished susceptibility of this Moraxella strain to penicillins. Since Moraxella strains may be resistant to these antibiotics, it is necessary to distinguish between Moraxella and N. meningitidis by means of laboratory tests. The symptoms elicited by Moraxella are similar to those in septicaemia caused by N. meningitidis, but are considerably milder in character.

Pattern of spatial distribution in Drosophila melanogaster.

The effect of temperature and sex on spatial distribution of Drosophila melanogaster adults was studied in a specially designed apparatus. It was observed that individuals tend to aggregate in sections of the sphere independently of sex and temperature. Nevertheless, decrease in temperature increase aggregation. The mobility of both males and females indicates a negative geotactic tendency.