Diagnostic Value of Multiplex Polymerase Chain Reaction in Detection of Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia from Sepsis in Pediatrics
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Proper identification of the causative organism in pediatric sepsis is crucial for early diagnosis and prevention of septic shock and organ failure.The aim of the present study was to evaluate the multiplex polymerase chain reaction (PCR) for detection of Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia from positive blood cultures for these pathogens isolated from children with hospital- acquired sepsis compared to the conventional biochemical reactions for identification of these organisms.This study was a cross-sectional study performed on 100 isolates from pediatric blood cultures, including Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The study also included 100 isolates of Escherichia coli as a negative control. All isolates were identified by API 20NE and the multiplex PCR with primers specific to the 3 tested bacteria.Multiplex PCR was positive in 96% of isolates and 4 isolates had negative results. Falsepositive results were reported with three E. coli strains. Multiplex PCR identified all the isolates of Acinetobacter baumannii, 29 isolates of Pseudomonas aeruginosa and 27 isolates of Stenotrophomonas maltophilia. The diagnostic value of the multiplex PCR compared to the biochemical identification revealed sensitivity 96.04%, specificity 96.9%, positive predictive value 97.00%, negative predictive value 96.00% and accuracy 96.50%.The present study highlights the diagnostic value of multiplex PCR to identify Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia from positive blood cultures. Multiplex PCR was sensitive, specific and accurate. The accuracy differs according to the organisms with 100% accuracy for Acinetobacter baumannii.Keywords:
Stenotrophomonas maltophilia
Acinetobacter baumannii
Multiplex
Stenotrophomonas
The aim of this study was to examine the frequency and predictors of colonization of the respiratory tract by metallo- β -lactamase (MBL)-producing Gram-negative bacteria in patients admitted to a newly established intensive care unit (ICU) of a tertiary care hospital. Specimens of tracheobronchial aspirates for microbiological studies were obtained every day for the first 3 days of the ICU stay and subsequently every third day for the rest of the ICU stay. PCR analysis and nucleotide sequencing were performed to identify bacteria that had MBL genes. Thirty-five patients (20 male, 15 female) were hospitalized during the initial 3 month period of functioning of the ICU. Colonization of the lower respiratory tract by Gram-negative bacteria was found in 29 of 35 patients (83 %) during the first 6–20 days (median 13 days) following admission to the ICU (13 patients with Acinetobacter baumannii , ten with Pseudomonas aeruginosa , three with Enterobacter aerogenes , two with Klebsiella pneumoniae and one with Stenotrophomonas maltophilia ). Six of 29 patients (21 %) colonized with Gram-negative bacteria had bla VIM-2 -positive P. aeruginosa isolates; one of these patients developed clinical infection due to this micro-organism. Previous use of carbapenems ( P =0.01) or other β -lactams ( P =0.03), as well as a stay in the ICU of >20 days ( P <0.001), were associated with colonization with bla VIM-2 -producing P. aeruginosa . In conclusion, colonization by Gram-negative bacteria of the respiratory tract of patients in this newly established ICU was common (83 %). Use of β -lactams, including carbapenems, was associated with subsequent colonization of the respiratory tract with MBL-positive P. aeruginosa .
Stenotrophomonas maltophilia
Acinetobacter baumannii
Enterobacter aerogenes
Respiratory tract
Stenotrophomonas
Gram-Negative Bacteria
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Nonfermentative gram-negative bacilli are still a major concern in compromised individuals. By far the most important of these organisms is Pseudomonas aeruginosa, although Acinetobacter baumannii (previously Acinetobacter calcoaceticus), Stenotrophomonas maltophilia (previously Pseudomonas and Xanthomonas maltophilia), and Burkholderia cepacia (previously Pseudomonas cepacia) are also of substantative concern because of their similar high intrinsic resistances to antibiotics. The basis for the high intrinsic resistance of these organisms is the lower outer-membrane permeability of these species, coupled with secondary resistance mechanisms such as an inducible cephalosporinase or antibiotic efflux pumps, which take advantage of low outer-membrane permeability. Even a small change in antibiotic susceptibility of these organisms can result in an increase in the MIC of a drug to a level that is greater than the clinically achievable level. In this review, the major mechanisms of resistance observed in the laboratory and clinic are summarized.
Stenotrophomonas maltophilia
Acinetobacter baumannii
Stenotrophomonas
Xanthomonas
Membrane permeability
Gram-Negative Bacteria
Efflux
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Abstract In hospitals, Verona Integron-encoded Metallo-beta-lactamase (VIM)-positive Pseudomonas aeruginosa may colonize sink drains, and from there, be transmitted to patients. These hidden reservoirs are difficult to eradicate since P. aeruginosa forms biofilms that resist disinfection. However, little is known on the composition of these biofilms. Therefore, culturomics was used for the first time to investigate the viable microbiota in four hospital sink drain samples with longstanding VIM-positive P. aeruginosa drain reservoirs (inhabited by high-risk clone, sequence type ST111), and four drain samples where VIM-positive P. aeruginosa was not present. Microbial load and composition varied between samples, yielding between 471–18,904 distinct colonies and 8–20 genera. In two VIM-positive drain samples, P. aeruginosa was the most abundantly-isolated microorganism, and found in combination with other Gram-negative bacteria, Citrobacter , Enterobacter , or Stenotrophomonas . P. aeruginosa was in low abundance in the other two VIM-positive samples, and found with Gram-positive cocci ( Enterococcus and Staphylococcus ) or Sphingomonas . In VIM-negative drain samples, high abundances of Gram-negative non-fermenting bacteria, including Acinetobacter , non-aeruginosa Pseudomonas spp., Acidovorax , Chryseobacterium , Flavobacterium , and Sphingobium , as well as Candida , were cultured. Although additional experiments are needed to draw more firm conclusions on which microorganisms enable or inhibit VIM-positive P. aeruginosa persistence, our data provide unique insights into the microbial compositions of sink drain inlets.
Stenotrophomonas
Stenotrophomonas maltophilia
Enterococcus faecalis
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Acinetobacter baumannii
Stenotrophomonas maltophilia
Stenotrophomonas
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Proper identification of the causative organism in pediatric sepsis is crucial for early diagnosis and prevention of septic shock and organ failure.The aim of the present study was to evaluate the multiplex polymerase chain reaction (PCR) for detection of Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia from positive blood cultures for these pathogens isolated from children with hospital- acquired sepsis compared to the conventional biochemical reactions for identification of these organisms.This study was a cross-sectional study performed on 100 isolates from pediatric blood cultures, including Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The study also included 100 isolates of Escherichia coli as a negative control. All isolates were identified by API 20NE and the multiplex PCR with primers specific to the 3 tested bacteria.Multiplex PCR was positive in 96% of isolates and 4 isolates had negative results. Falsepositive results were reported with three E. coli strains. Multiplex PCR identified all the isolates of Acinetobacter baumannii, 29 isolates of Pseudomonas aeruginosa and 27 isolates of Stenotrophomonas maltophilia. The diagnostic value of the multiplex PCR compared to the biochemical identification revealed sensitivity 96.04%, specificity 96.9%, positive predictive value 97.00%, negative predictive value 96.00% and accuracy 96.50%.The present study highlights the diagnostic value of multiplex PCR to identify Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia from positive blood cultures. Multiplex PCR was sensitive, specific and accurate. The accuracy differs according to the organisms with 100% accuracy for Acinetobacter baumannii.
Stenotrophomonas maltophilia
Acinetobacter baumannii
Multiplex
Stenotrophomonas
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Synergistic interactions in mixed-species biofilms of pathogenic bacteria from the respiratory tract
Introduction Mixed-species biofilms are involved in a wide variety of infections. We studied the synergistic interactions during dual-species biofilm formation among isolates of Pseudomonas aeruginosa, Acinetobacter baumannii, and Stenotrophomonas maltophilia. Methods Isolates were cultured as single-species and all possible combinations of dual-species biofilms. Results The 61 A. baumannii biofilms increased by 26-fold when cultured with S. maltophilia isolates; 62 A. baumannii biofilms increased by 20-fold when cultured with S. maltophilia isolates; and 31 P. aeruginosa biofilms increased by 102-fold when cultured with S. maltophilia 106. Conclusions Synergy was observed between two isolates, including those that inherently lacked biofilm formation ability.
Stenotrophomonas maltophilia
Acinetobacter baumannii
Stenotrophomonas
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We tested the effects of various putative efflux pump inhibitors on colistin resistance in multidrug-resistant Gram-negative bacteria. Addition of 10 mg/liter cyanide 3-chlorophenylhydrazone (CCCP) to the test medium could significantly decrease the MICs of colistin-resistant strains. Time-kill assays showed CCCP could reverse colistin resistance and inhibit the regrowth of the resistant subpopulation, especially in Acinetobacter baumannii and Stenotrophomonas maltophilia These results suggest colistin resistance in Gram-negative bacteria can be suppressed and reversed by CCCP.
Colistin
Stenotrophomonas maltophilia
Efflux
Acinetobacter baumannii
Gram-Negative Bacteria
Stenotrophomonas
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OBJECTIVE To investigate the distribution and resistance of non-fermenting bacteria isolated from our hospital and offer the basis for the treatment of bacterial infection.METHODS Totally 2177 strains of non-fermenting bacteria were isolated from clinical sputum samples between Jan 2006 and Dec 2008.All of the isolated bacteria were identified with API identified test(API Inc,France) and Kirby-Bauer(K-B) test used for the antibiotics susceptive test.RESULTS From them the most common bacteria were Pseudomonas auruginosa(34.9%),followed by Acinetobacter baumannii(28.4%) and Stenotrophomonas maltophilia(11.4%).These bacteria had various resistances to the tested antibiotics.CONCLUSIONS Non-fermenting bacteria have high isolate rate and multi-antibiotic resistance,so antibiotics should be correctly used under the guidance of antibiotic susceptibility test.
Stenotrophomonas maltophilia
Acinetobacter baumannii
Stenotrophomonas
Pathogenic bacteria
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We used 62 strains initially identified as non fermenting gram-negative bacilli (NFGNB) isolated from patients with a nosoco- mial infection diagnosis with the purpose of identifying their genus and species. Forty five strains were identified as Acinetobacter baumannii, 10 as Pseudomonas aeruginosa, 3 as Stenotrophomonas maltophilia, 3 as Comamonas acidovorans and 1 as Achromobacter xylosoxidans subspecies xylosoxidans through the API 20NE. Regarding the Acinetobacter strains, the ARDRA allowed to identify 20 strains as A. baumannii and 23 as Acinetobacter genospecies 13TU, but 2 strains were not identified with this method. The ADNr 16S sequence of all the strains included in this study allowed to identify 20 strains as A. baumannii, 23 strains as Acinetobacter RUH1139, 10 as P. aeruginosa, 4 as A. xylosoxidans subsp. xylosoxidans (2 of these four strains strains had been identified as A. baumannii through API20NE), 3 as S. maltophilia, and 1 as C. acidovorans and 1 as β-Proteubacterium. The discrepancies between the biochemical identifi- cation by API 20NE and by ARDRA to differentiate the Acinetobacter genospecies was resolved by the ADNr16S sequencing, indicating that the identification of the Acinetobacter isolates, among other NFGNB, through API 20NE, should be confirmed through genetic tech- niques.
Achromobacter xylosoxidans
Acinetobacter baumannii
Stenotrophomonas maltophilia
Stenotrophomonas
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