In recent years, MALDI-TOF Mass Spectrometry (MS) method has emerged as a promising and a reliable tool for bacteria identification. In this study we compared Bruker MALDI-TOF MS and conventional ...phenotypic methods to identify a collection of 333 Gram-positive clinical isolates comprising 22 genera and 60 species. 16S rRNA sequencing was the reference molecular technique, and rpoB gene sequecing was used as a secondary gene target when 16Sr RNA did not allow species identification of Corynebacterium spp. We also investigate if score cut-offs values of ≥ 1,5 and ≥ 1,7 were accurate for genus and species-level identification using the Bruker system. Identification at species level was obtained for 92,49% of Gram-positive rods by MALDI-TOF MS compared to 85,89% by phenotypic method. Our data validates the score ≥ 1,5 for genus level and ≥ 1,7 for species-level identification in a large and diverse collection of Gram-positive rods. The present study has proved the accuracy of MALDI-TOF MS as an identification method in Gram-positive rods compared to currently used methods in routine laboratories.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) to identify 396 Nonfermenting Gram-Negative Bacilli clinical isolates was evaluated in comparison with ...conventional phenotypic tests and/or molecular methods.
MALDI-TOF MS identified to species level 256 isolates and to genus or complex level 112 isolates. It identified 29 genera including uncommon species.
•MALDI-TOF MS had a good performance in the identification of 29 genera of NFGNB.•MALDI-TOF MS is a useful tool for the rapid diagnosis of NFGNB including rare species.•MALDI-TOF MS database needs to be expanded and updated for better performance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Desulfovibrio spp. are strict anaerobes that are ubiquitous in nature. They can reside in the human or animal gastrointestinal tract and, as they are also environmental bacteria, may be present in ...soil and water. They can persist asymptomatically in the intestine or behave as opportunistic pathogens associated with primary bacteremia and intraabdominal infections. Several Desulfovibrio spp. infections may be underestimated due to their slow growth rate and because many laboratories do not routinely perform anaerobic cultures. Simple tests such as motility detection on a fresh subculture, Gram stain to confirm cell morphology, presence of H
S in SIM agar and production of a red fluorescence in alkaline pH under UV light would be indicative of Desulfovibrio spp. Here we report the case of Desulfovibrio desulfuricans bacteremia in a woman with clinical picture of abdominal sepsis due to gangrenous appendicitis with multiple organ failure.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Acinetobacter johnsonii rarely causes human infections. While most A. johnsonii isolates are susceptible to virtually all antibiotics, strains harboring a variety of β-lactamases have recently been ...described. An A. johnsonii Aj2199 clinical strain recovered from a hospital in Buenos Aires produces PER-2 and OXA-58. We decided to delve into its genome by obtaining the whole genome sequence of the Aj2199 strain. Genome comparison studies on Aj2199 revealed 240 unique genes and a close relation to strain WJ10621, isolated from the urine of a patient in China. Genomic analysis showed evidence of horizontal genetic transfer (HGT) events. Forty-five insertion sequences and two intact prophages were found in addition to several resistance determinants such as blaPER-2, blaOXA-58, blaTEM-1, strA, strB, ereA, sul1, aacC2 and a new variant of blaOXA-211, called blaOXA-498. In particular, blaPER-2 and blaTEM-1 are present within the typical contexts previously described in the Enterobacteriaceae family. These results suggest that A. johnsonii actively acquires exogenous DNA from other bacterial species and concomitantly becomes a reservoir of resistance genes.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In the last years, an increasing number of untreatable infections caused by drug-resistant microbes have impacted the health care system. Worldwide, infections caused by carbapenem-resistant (CR) ...Gram-negative bacilli have dramatically increased. Among the CR-Gram-negative bacilli, those producing carbapenemases, such as NDM-1, are the main concern. Different
Enterobacterales
harboring NDM-1 have been reported lately.
Providencia stuartii
, a member of the
Morganellaceae
family, is ubiquitous in the environment, but is also known to cause nosocomial infections. Here we describe the genomic analysis of two NDM-1- producing
P. stuartii
strains recovered from the same patient as well as other carbapenem resistant strains recovered from the same hospital. As a result of the genomic analysis thirteen resistance genes, including three to β-lactams (
bla
OXA-1
,
bla
TEM-1
,
bla
NDM-1
), four to aminoglycosides (
aphA6, aac(3)-IId, aac(2′)-Ia
,
aac(6′)-Ib-cr5
), one to sulfonamides (
sul1
), two to chloramphenicol (
catB3, catA3
), one to rifampicin, one to bleomycin (
ble
), and one to tetracycline (
tet(B)
) were found. Moreover, a variety of mobile genetic elements, such as insertion sequences, plasmids and phage- related sequences, were found within
P. stuartii
genomes. The spread of carbapenem-resistant isolates remains a significant clinical and public health concern. Therefore, we considered that the detection of CR isolates is an essential step in addressing this problem.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Dolosigranulum pigrum in corneal abscess Roitman, Karina L; Almuzara, Marisa N; Fernández Rodriguez, Mario Javier ...
Revista argentina de microbiología,
04/2022
Journal Article
Peer reviewed
Open access
Dolosigranulum pigrum is a gram-positive, facultatively anaerobic coccus, which is part of the oral and upper respiratory tract microbiota. Although reports of infections by this microorganism are ...scarce, it has been associated with a wide spectrum of infectious diseases. The case of an elderly man with a lower corneal abscess, in which Dolosigranulum pigrum was isolated, is described. The microorganism was identified by mass spectrometry (MALDI-TOF MS) and by the sequencing of the 16S rRNA gene. Furthermore, the presumptive identification of the causative agent was achieved by using key phenotypic tests such as the cluster arrangement in Gram stain, the negative catalase test, the production of pyrrolidonyl arylamidase and leucine aminopeptidase activity, the growth in 6.5% NaCl and esculin hydrolysis. The data from the literature (and the present case) support the association of the microorganism with ocular infections, which often take a destructive course, mainly in elderly patients.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Non-diphtheria
Corynebacterium
species (NDC) belonging to the human skin and mucosa microbiota are frequently neglected as contaminants. However, reports of human infections by
Corynebacterium
spp. ...have increased considerably in recent years. In this study, a group of six NDC isolates of urine (
n
= 5) and sebaceous cyst (
n
= 1) from two South American countries were identified at genus level or misidentified based on API® Coryne and genetic/molecular analyses. The 16S rRNA (99.09–99.56%) and
rpo
B (96.18–97.14%) gene sequence similarities of the isolates were higher when compared with
Corynebacterium aurimucosum
DSM 44532
T
. Multilocus sequence analysis (MLSA) indicated that these six NDC isolates compose a distinctive phylogenetic clade. Genome-based taxonomic analysis with the whole-genome sequences was able to separate these six isolates from other known
Corynebacterium
type strains. Average nucleotide identity (ANI), average amino acid identity (AAI), and digital DNA–DNA hybridization (dDDH) values between closely related type strains and the six isolates were considerably lower than the currently recommended threshold values for species circumscription. Phylogenetic and genomic taxonomy analyses indicated these microorganisms as a novel
Corynebacterium
species, for which we formally propose the name
Corynebacterium guaraldiae
sp. nov. with isolate 13
T
(= CBAS 827
T
= CCBH 35012
T
) as type strain.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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