Molecular identification of bacteria in tracheal aspirate fluid from mechanically ventilated preterm infants

Background

Despite strong evidence linking infections to the pathogenesis of bronchopulmonary dysplasia (BPD), limitations of bacterial culture methods have precluded systematic studies of airway organisms relative to disease outcomes. Application of molecular bacterial identification strategies may provide new insight into the role of bacterial acquisition in the airways of preterm infants at risk for BPD.

Methods

Serial (within 72 hours, 7, 14, and 21 days of life) tracheal aspirate samples were collected from 10 preterm infants with gestational age ≤34 weeks at birth, and birth weight of 500–1250 g who required mechanical ventilation for at least 21 days. Samples were analyzed by quantitative real time PCR assays for total bacterial load and by pyrosequencing for bacterial identification.

Results

Subjects were diagnosed with mild (1), moderate (3), or severe (5) BPD. One patient died prior to determination of disease severity. 107,487 sequences were analyzed, with mean of 3,359 (range 1,724–4,915) per sample. 2 of 10 samples collected <72 hours of life contained adequate bacterial DNA for successful sequence analysis, one of which was from a subject exposed to chorioamnionitis. All other samples exhibited bacterial loads >70copies/reaction. 72 organisms were observed in total. Seven organisms represented the dominant organism (>50% of total sequences) in 31/32 samples with positive sequences. A dominant organism represented>90% of total sequences in 13 samples. Staphylococcus, Ureaplasmaparvum, and Ureaplasmaurealyticum were the most frequently identified dominant organisms, but Pseudomonas, Enterococcus, and Escherichia were also identified.

Conclusions

Early bacterial colonization with diverse species occursafter the first 3 days of life in the airways of intubated preterm infants, and can be characterized by bacterial load and marked species diversity. Molecular identification of bacteria in the lower airways of preterm infants has the potential to yield further insight into the pathogenesis of BPD.     

Aspergillus taichungensis,a new species from Taiwan

Aspergillus taichungensis isolated from a soil sample collected in Taiwan is described as a new species. The new species is characterized by its restricted growth on Czapek's and malt extract agars and its white to light yellow colonies, radiate conidial heads, smooth and often diminutive conidiophores, hemispherical to elongate vesicles with biseriate aspergilla (conidiogenous cells), globose, micro-verrucose conidia and dark brown sclerotia. The species somewhat resemblesA. versicolor, A. terreus andA. flavipes, but differs in cultural and morphological details, and is considered to represent an interface species in the subgenusNidulantes.     

Talaromyces euchlorocarpius, a new species from soil

A new species ofTalaromyces, characterized by development of unusual deep green ascomata on common media, is described and given the nameTalaromyces euchlorocarpius. This species, isolated from soil, also produces ellipsoidal, spinose ascospores, typically biverticillate penicilli, large ellipsoidal, smooth-walled conidia, and is assigned to the seriesLutei of the sectionTalaromyces.     

Fusarium nisikadoi, a new species from Japan

A new species ofFusarium, F. nisikadoi, isolated fromPhyllostachys nigra var.henonis (bamboo) andTriticum aestivum (wheat) in Japan, is described, illustrated and discussed. This species is differentiated from other known species of the genus by the following characteristics: whitish colony color, long zigzag-like chains of 0–3(-5)-septate clavate conidia, intermixed with pyriform conidia, produced mostly from monophialides and rarely from polyphialides in the aerial mycelium, very long and slender sporodochial conidia, and no chlamydospores. The long chains of septate conidia are known only in this species of the genusFusarium. The conidiophores on the aerial mycelium sometimes proliferate sympodially. The species is tentatively placed in the form-sectionLiseola.     

Bovista sclerocystis, a new species from Mexico

Bovista sclerocystis is described as a new species. It was found in Mexico, growing on rich soil of a tropical forest. It belongs to section Globaria, series Albosquamosa. The most striking character of this taxon is the exoperidium composed of polymorphous mycosclereids.     

Herberta borealis,a new species from Scotland and Norway

Abstract

The reproduction of Pohlia nutans (Hedw.) Lindb. and Pleurozium schreberi (Brid.) Mitt. were compared in the surroundings of copper smelters at Harjavalta, Finland. Samples of both species were collected from 16 sample plots, which were situated on a 12-km transect at intervals of half a kilometre from the smelters. As a result of pollution the production of gametangia decreased in P. schreberi, and near the smelters most of the shoots were sterile. The biomass of shoots seems to have an effect on the production of perichaetia; reproducing females were always the largest ones in the colonies. The reproductive strategy of Pohlia nutans also varied. While, in moderately clean areas, colonies reproduced sexually and formed sporophytes, in the vicinity of the smelters caducous shoot apices were produced. The numbers of sporophytes in colonies were highest in moderately polluted areas and decreased further away from the smelters. The numbers of spores per capsule in P. nutans decreased at polluted sites and the proportion of aborted spores increased.     

A new species of Pseudorobillarda, an endophyte from Thuja occidentalis in Canada, and a key to the species

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Fissidens traversii,a new species from Queensland,Australia

Abstract

Fissidens traversii, a new species from Queenslahd, Australia, is characterised by the rounded leaf apex, costa papillose and finishing short of the apex, mamillose, multipapillose cells, short dorsal lamina and vaginant laminae (which usually have a marginal strip of transversely elongated calls in the lower half), reaching almost to the apex of the leaf.     

Description of a new species of Wormaldia from Sardinia and a new Drusus species from the Western Balkans (Trichoptera,Philopotamidae, Limnephilidae)

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Coprinol, a new antibiotic cuparane from a Coprinus species

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Aspergillus salviicola,a new species from imported spice

A new species ofAspergillus, A. salviicola, has been isolated from Turkish sage, an imported spice in Japan. The species, characterized by white to rosy buff conidial heads, pinkish smooth-walled conidiophores, large biseriate aspergilla, globose smooth-walled conidia, absence of sclerotia and thermotolerant growth, is considered to represent an interface species in the subgenusCircumdati.     

Emericella appendiculata, a new species from Chinese soil

Emericella appendiculata, a new species isolated from soil of the Pamire Plateau, is described and illustrated. It is characterized by grayish green non-ostiolate ascomata surrounded by a thick layer of hülle cells, membranaceous peridium, prototunicate asci, violet-brown, lenticular ascospores which are ornamented by two stellate equatorial crests, capitate convex surfaces, and long filiform appendages, and anAspergillus anamorph with biseriate conidiogenous cells.     

Talaromyces lagunensis,a new species from Philippine soil

A new species ofTalaromyces (Ascomycetes; Trichocomaceae) with aPenicillium anamorph,T. lagunensis, is described and illustrated. This fungus is characterized by its extremely restricted growh on Czapek-yeast extract agar, light yellow to light orange ascomata with a telaperidium, catenate, pyriform or ellipsoidal asci, ellipsoidal or subglobose ascospores with a microtuberculate wall, short conidiophores with an irregular, mostly monoverticillate to biverticillate penicillus, and subglobose to ovoid conidia. The holotype was isolated from forest soil in the Philippines.     

Spiromastix saturnispora,a new species from indonesian soil

Spiromastix saturnispora, isolated from a soil sample collected from central Java in Indonesia, is described and illustrated as a new species. The new species was compared with the type ofSpiromastix, S. warcupii, and is similar in having brownish ascomata with a peridium of a loose network of delicate hyphae, peridial appendages which are curved in the manner of a scimitar and never completely coiled, and the absence of an anamorph. The ascospores ofS. saturnispora are characterized as large oblate, 3.2–4.8 × 2.5–3µm, punctate, and with an equatorial rim, which serves to distinguish the species fromS. warcupii and other known species.     

Thielavia aurantiaca, a new species from Japanese soil

A new species ofThielavia (T. aurantiaca) isolated from field soil collected from Osaka is described and illustrated. The fungus is distinguished from other known species by having ascomata covered with yellowish orange mycelium and smaller size of ascomata and ascospores. A chlamydospore-like anamorph is formed.     

Aristolochia translucida,a new species from Costa Rica

A new species from Costa Rica,Aristolochia translucida, is described and its relationships to other species detailed.