Pneumonia in mechanically ventilated patients: no diagnostic and prognostic value of different quantitative tracheal aspirates thresholds

BACKGROUND

Diagnosis of pneumonia in ventilated patients is challenging due to the lack of specific and definitive clinical symptoms, laboratory data or radiological abnormalities.

METHODS

Based on quantitative tracheal aspirate (QTA) results, three groups of patients were compared: <10⁵ cfu/ml, ≥10⁵ cfu/ml and <10⁶ cfu/ml, and ≥10⁶ cfu/ml. We recorded demographic variables, underlying diseases and severity of illness at ICU admission. On the day of pneumonia diagnosis, we registered temperature, leukocyte count, C-reactive protein, Sequential Organ Failure Assessment (SOFA) score, clinical pulmonary infection score (CPIS) and adequacy of empirical antimicrobial therapy.

RESULTS

In 231 episodes, clinical presentation, laboratory data, severity of illness, CPIS, the presence of bacteremia and radiological score did not differ among the three groups. ICU and hospital mortalities were also similar in the three groups. Factors independently associated with in-hospital mortality were age, SOFA score and inappropriate antimicrobial therapy. The bacterial burden in the QTA was not included in the model.

CONCLUSIONS

Quantification of tracheal aspirate samples may not be necessary in ventilated patients clinically suspected of having nosocomial pneumonia.

Phagocytosis, oxidative burst, and produced reactive species are affected by iron deficiency anemia and anemia of chronic diseases in elderly

Iron and oxidative stress have a regulatory interplay. During the oxidative burst, phagocytic cells produce free radicals such as hypochlorous acid (HOCl). Nevertheless, scarce studies evaluated the effect of either iron deficiency anemia (IDA) or anemia of chronic disease (ACD) on phagocyte function in the elderly. The aim of the present study was to determine the oxidative burst, phagocytosis, and nitric oxide (*NO) and HOCl, reactive species produced by monocytes and neutrophils in elderly with ACD or IDA. Soluble transferrin receptor, serum ferritin, and soluble transferrin receptor/log ferritin (TfR-F) index determined the iron status. The study was constituted of 39 patients aged over 60 (28 women and 11 men) recruited from the Brazilian Public Health System. Oxidative burst fluorescence intensity per neutrophil in IDA group and HOCl generation in both ACD and IDA groups were found to be lower (p < 0.05). The percentages of neutrophils and monocytes expressing phagocytosis in ACD group were found to be higher (p < 0.05). There was an overproduction of *NO from monocytes, whereas the fundamental generation of HOCl appeared to be lower. Phagocytosis, oxidative burst, and *NO and HOCl production are involved in iron metabolism regulation in elderly patients with ACD and IDA.

Changes in amounts of total salivary gland proteins of Lutzomyia longipallpis (Diptera: Psychodidae) according to age and diet

Saliva plays important roles in facilitation of a bloodmeal, lubrication of mouthparts, and parasite transmission for some vector insects. Salivary composition changes during the lifetime of an insect, and differences in the salivary profile may influence its functions. In this report, the amount and profile of salivary gland protein of the American visceral leishmaniasis vector Lutzomyia longipalpis (Lutz & Neiva, 1912) were analyzed at different times of insect development and diet. Protein content from unfed female sand flies increased significantly with age, and a significant difference was observed in sugar-fed females during the first 10 d of adult life. Salivary protein content sharply decreased 1 d after blood feeding, with gradual increase in concentration the following days. SDS-polyacrylamide gel electrophoresis analysis revealed that most polypeptides present in the saliva of sugar-fed also were present in the saliva of blood-fed females. Understanding changes in sand fly's saliva contents at distinct days after emergence and the influence of a bloodmeal in this aspect may reveal the role played by saliva during leishmaniasis transmission.

Morphometric and phenetic studies of five geographical populations of Lutzomyia whitmani (Diptera: Psychodidae) in Brazil

A morphometric survey examined adult specimens of Lutzomyia whitmani (Antunes & Coutinho) captured at 5 municipalities in southeastern and northeastern Brazil to compare the populations. The localities were Ilhéus (Bahia), Martinho Campos (Minas Gerais), Corte de Pedra (Bahia), Baturité (Ceará), and Amaraji (Pernambuco): all are known foci of American cutaneous leishmaniasis. Fifteen males and 15 females from each population were analyzed morphometrically for 42 and 37 characters, respectively. Statistical data alone were insufficient to discriminate among the 5 populations. Further analysis generated phenograms that indicated there were 2 spatial clusters: the 1st was composed of specimens from Ilhéus (Bahia) and Baturité (Ceará) and the 2nd of specimens from Martinho Campos (Minas Gerais), Corte de Pedra (Bahia), and Amaraji (Pernambuco). Although insufficient to define the taxonomic status of the populations studied, the results delineated the existence of biogeographical structuring within L. whitmani. Complementary studies on the susceptibility to Leishmania braziliensis infection in the 5 populations are in progress to clarify the relationship between the 2 biogeographical clusters and American cutaneous leishmaniasis transmission in those Brazilian regions.

[Outbreak of American cutaneous leishmaniasis in Canoa, Santo Amaro, Bahia, Brazil]

An outbreak of American cutaneous leishmaniasis (ACL) was detected in the village of Canoa in 1993. A prospective observational study was outlined to determine the frequency rates and to clinically characterize the disease. A total of 555 people were followed up. There were 29 cases of ACL, 11 cases of probably previous ACL (scars) and 529 healthy individuals. Of these 529 individuals, 65 had a positive Montenegro reaction without any present or past evidence of leishmaniasis. The prevalence of ACL during the two years was 5.2% (29/555). The leishmania involved was Leishmania braziliensis and the vector, Lutzomyia intermedia. Evidence of infection was detected in dogs and horses. The high frequency of the disease among children under ten years, the similar sex distribution of cases and a component of familial aggregation suggest a peri- or intra-domiciliary transmission.

Comparison of the polymerase chain reaction and serology for the detection of canine visceral leishmaniasis

The polymerase chain reaction (PCR) and serology was evaluated for the diagnosis of canine visceral leishmaniasis in Bahia, Brazil in a study of 125 dogs. The PCR was 100% sensitive in 25 dogs that had Leishmania demonstrated by either culture or hamster inoculation. It was 100% specific for 35 dogs from the northeastern United States, all were PCR negative. However, 22 of 54 Brazilian dogs that were culture-hamster inoculation-negative were positive by PCR. The nature of the PCR product was identified by hybridization with specific Leishmania probes. Whereas the sensitivity of serology in relationship to infection, as determined by hamster or culture assay was more than 80%, sensitivity of serology was only 63% when compared with PCR. These results raise questions about the use of serology to detect Leishmania infection in dogs, and suggest that the PCR might serve as a better gold standard to define Leishmania infection than culture or hamster inoculation.

[Intestinal geohelminthosis in man and domestic animals in the riverside sections of the Valdivia River Basin, Chile]

In March-October 1987 were analyzed 1295 coprological specimens in a sample of the human population who lives in riverside localities in the Valdivia River Basin, Chile. A 23.6% of examined persons presented infection by one or more helminth species. The prevalence of infection by Ascaris lumbricoides, Trichuris trichiura and Trichostrongylidae gen. sp. were 15.5, 12.7 and 0.2%, respectively. The prevalence of human ascariosis and trichuriosis were greater in pre-school and school children. The sex of the host and prevalence of geohelminthosis did not show any relationship. Prevalences of ascariosis and trichuriosis were higher in persons from houses with no sanitary fecal and water disposal. Over 35% and 20.7% of family groups showed infection by A. lumbricoides and T. trichiura, respectively in over 40% of the members of each group. Fecal samples from domestic mammals revealed the following prevalences rates for helminth infections: in dogs 19.0 and 15.2% for Toxocara canis and Uncinaria stenocephala respectively, in cats 65.1% for Toxocara cati, and in pigs 25.4 and 3.2% for Ascaris suum and Trichuris suis respectively. Some of these species are clearly demonstrated agents of zoonoses.

[Blastocystosis and other intestinal protozoan infections in human riverside communities of the Valdivia River basin, Chile]

Between March and October 1987, the prevalence of infection by Blastocystis hominis and other intestinal protozoan, their relationship with the age and sex of the hosts, and the percentage of infected persons in family groups were determined in riverside communities of Valdivia River Basin, Chile. One or more intestinal protozoan species were determined in 72.5% of the examined persons. The prevalence was greater for B. hominis (61.8%). The prevalences of B. hominis, Endolimax nana and Entamoeba coli were greater in relation to the age of the host. The sex of the host and prevalence of infections by B. hominis and other species of intestinal protozoans did not show association. Prevalence of B. hominis was greater in persons from houses with no sanitary faeces disposal. Over 60% of the members of family groups showed infection by B. hominis in 53.1% of the groups compared to 2.4%-21.8% of infections by other protozoan species. Faecal samples of 45 pigs revealed 22.2% of infection by Blastocystis.

Ecological aspects of nematode parasites of introduced salmonids from Valdivia river basin, Chile

Between 1986 and 1987, 666 fishes distributed among the following species introduced in Chile, and from different sectors of the Valdivia river basin (39 degrees 30'-40 degrees 00'S, 73 degrees 30'-71 degrees 45'W), were examined: 348 Salmo trutta, 242 Salmo gairdneri, 24 Cyprinus carpio and 52 Gambusia affinis holbrooki. The presence of Camallanus corderoi and Contracaecum sp. in S. gairdneri and of C. corderoi in S. trutta is recorded in Chile for the first time. Cyprinus carpio and G. a. holbrooki did not present infections by nematodes. The prevalence and mean intensity of the infections by nematodes presented significant differences among some sectors of the Valdivia river basin. In general, the prevalence and intensity of the infections by C. corderoi were greater than those by Contracaecum sp. The infections in S. gairdneri were higher than in S. trutta. The sex of the hosts had no influence on the prevalence and intensity of the infections by both nematodes. The length of the hosts did have an influence, except in the case of the infections by Contracaecum sp. in S. gairdneri. The infrapopulations of both nematode species showed over-dispersion in most cases. The diet of the examined salmonids suggests that they would become infected principally through the consumption of autochthonous fishes.

[Epidemiology of diphyllobothriasis in the Valdivia river basin, Chile]

In the Valdivia (Chile) river basin 1,295 inhabitants of 6 riverside districts were examined between March and October 1987 and showed a 1.2% of prevalence by Diphyllobothrium in the districts of Riñihue and Las Huellas. Prevalence of 5.3% and 9.8% respectively were registered in dogs of the districts of Riñihue and Malihue. No cat or pig infection was observed in the different districts. The parasites recovered after the treatment were identified as Diphyllobothrium latum. Human infection by D. latum in the districts affected results from the consumption of smoked or insufficiently cooked fish. The investigation of 1,450 fish (4 exotic species and 11 autochthonous ones), caught in the Valdivia river basin in 1986 and 1987, showed the existence of plerocercoids of D. latum and/or Diphyllobothrium dendriticum in Salmo gairdneri and Salmo trutta among exotic fish and in some autochthonous species. Prevalence and mean intensity in the infection of fish as well as the degree of aggregation in the infrapopulations varied in the different districts. Some species of fish would act as intermediary hosts and others as paratenic hosts in the life cycles of Diphyllobothrium spp. in the Valdivia river basin. An improvement in the conditions of basic sanitation, in sanitary education and in the treatment of infected persons is proposed as a means for the control of diphyllobothriasis in the districts affected.

Junctional specializations in the seminiferous epithelium of an insect (Triatoma infestans): a freeze fracture and lanthanum tracer study

Intercellular junctions in the seminiferous epithelium of the testis of Triatoma infestans were examined by conventional electron microscopy, tannic acid fixation, electron-opaque tracers, and freeze-fracture techniques. Distinctive aspects of the intercellular junctions are described in different regions of the testis follicles. In the basal region, close to the basal lamina, smooth septate junctions intermingled with gap junctions were observed between sustentacular cells. In the parabasal regions of the seminiferous epithelium, plated septate junctions, 'molluscous and arthropod' type (according to the classification of Green, 1981), were observed. Over the above junctions, in the central regions, also located between sustentacular cell membranes, parallel rows of intramembrane particles form successive belts of widely spaced septate junctions in an atypical configuration. Invertebrate gap junctions were also observed between adjacent spermatocyte membranes.

[Observations on kala azar in Jacobina, Bahia. VI. Investigations on sylvatic and commensal mammals]

Durante os anos de 1982 a 1986, a investigação sobre mamíferos comensais e silvestres, da periferia da cidade de Jacobina, Bahia, mostrou, ao lado do escasso número de exemplares, uma reduzida variedade específica dessa fauna. Capturou-se apenas 11 espécies, entre as quais, predominou o Didelphis albiventris, que abrangeu 44% dos 213 espécimens capturados. Entre os 193 com exames já concluídos, 84 eram exemplares de D. albiventris e 2 estavam infectados pela Leishmania donovani senso lato, 1 por L. mexicana amazonensis, 1 por L. braziliensis, subespécie e 3 por Trypanosoma cruzi Também foram observadas formas suspeitas de serem amastigotas de leishmanics, nos esfregaços de órgãos de 3 exemplares de Dasyprocta aguti, 1 Cercomys cunicularius - e 1 Oryzomys eliurus. 0 restante dos exemplares, inclusive 14 de Lycalopex vetulus, estava negativo para flagelados. Apesar de reforçado por outros indicadores epidemiológicos, como a predominância específica, a freqüência domiciliar, a atratividade para a vetora Lutzomyia longipalpis, e a concomitância com casos humanos nos mesmos locais, o índice de 2,3% de infecção natural do Didelphis albiventris, não autoriza a conclusão definitiva de ser o marsupial o mais importante reservatório natural da leishmaniose visceral em Jacobina.

Natural infection of the opossum Didelphis albiventris (Marsupialia, Didelphidae) with Leishmania donovani, in Brazil

An opossum, Didelphis albiventris, from Jacobina, Bahia State, was found naturally infected with Leishmania donovani, being the first non-canid wild mammal to be detected with the agent of kala-azar in the New World.

Gentamicin absorption during prophylactic use for necrotizing enterocolitis

Gentamicin absorption was measured after oral administration in 18 neonates treated prophylactically in an attempt to decrease the incidence of necrotizing enterocolitis. Patients were given 10 mg/kg/day in four divided doses via nasogastric tube for a total of 10 days. Levels were assayed using the Emit system. Serum levels ranged between 0 and 2.2 micrograms/ml. Mean levels over 10 days were 0.42 +/- (SD) 0.47 micrograms/ml and did not vary significantly from day to day. From these data we conclude that enterally administered gentamicin is not absorbed to a degree that would result in toxic or even therapeutic serum concentrations.

Chromaffin reactions and fluorometric determination of catecholamines in the neonatal adrenal medulla of the rat

Adrenaline and noradrenaline fluorometric determinations were simultaneously made in adrenal glands of 2-to-10 day-old rat with the histochemical localization of total catecholamines and noradrenaline. In 10-day-old-rats the increase is three times higher for adrenaline and four times higher for noradrenaline compared to 2nd day of age. Chromaffin cells of 2-to-10-day-old rats showed a low granular population preferentially located in the periphery of the cells. Seven days after birth the chromaffin granules were numerous and dispersed in extense areas of the cytoplasm. The dichromate reactions for total catecholamines were positive from the 5th day of age when the fluorometric determination was 250 ng of catecholamines (CA) per gland. The glutaraldehyde silver technique for noradrenaline was positive from the 7th day when the fluorometric determination was 35 ng of noradrenaline (NA) per gland. However, at the electron microscope level, this last reaction shows the same silver precipitates on the chromaffin granules in adrenal glands obtained from 4-to-6-day-old rats. These results indicate that the appearance and evolution of the chromaffin positive reaction during post natal development is a direct expression of molecular changes during maturation of the granular complex.

Effect of dexamethasone on the neonatal adrenal medulla

Newborn male rats were injected with a single dose of dexamethasone on the first day of life. Controls received only the diluent. Two to ten days later the experimental and control animals were sacrificed, and the adrenal medullae were processed for electron microscopy and for histochemical demonstration of catecholamines. Rats that received dexamethasone, as compared to controls showed (1) an earlier appearance of the catecholamine reactions, and (2) a pronounced development of Golgi complex. These results are further indication that glucocorticoid stimulates the maturation of the chromaffin complex. The Golgi apparatus may play some role in this inductive mechanism.