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MSphere Jan 2021nasal carriage provides the bacterial reservoir for opportunistic infection. In comparing the nasal microbiomes of culture-defined persistent carriers versus...
nasal carriage provides the bacterial reservoir for opportunistic infection. In comparing the nasal microbiomes of culture-defined persistent carriers versus noncarriers, we detected DNA in all noses, including those with an established history of negativity based on culture. Colonization with , including , , , and select spp., was associated with noncarriage. We next developed physiological competition assays for testing anti- activity of isolated nasal species, utilizing medium modeling the nutrient-limited fluid of the nasal mucosa, polarized primary nasal epithelia, and nasal secretions. from the nose of an noncarrier demonstrated >99% inhibition of recovery in all assays, even when was coincubated in 9-fold excess. Secreted inhibitory proteins from and were heat-stable and <30 kDa, fitting the profile of antimicrobial peptides. , , , and inhibited recovery on nasal epithelia in a contact-dependent manner, while several other species either had no effect or promoted growth. Collectively, this project is one of the first to identify resident nasal microbial species that impede survival, and it implies that detectable nasal results from shifts in microbial community composition. Nasal carriage of is a risk factor for infection, but it is not yet understood why some individuals carry nasal persistently, intermittently, or seemingly not at all when tested via culture methods. This study compared the nasal microbiomes of established carriers and noncarriers, identified species associated with noncarriage, and tested them for anti- activity using assays developed to model the nutrient-limited nasal mucosa. We determined that all nostril swabs contain DNA, even swabs from hosts considered to be long-term noncarriers. Select members of the class were more prevalent in noncarrier than carrier nostrils and demonstrated potent activity against multiple strains of The results described here provide a better understanding of how the nasal microbiome controls growth and viability and may be useful in the design of improved decolonization strategies.
Topics: Anti-Bacterial Agents; Antibiosis; Carrier State; Cells, Cultured; Epithelial Cells; Gammaproteobacteria; Humans; Microbiota; Nasal Cavity; Staphylococcus aureus
PubMed: 33408227
DOI: 10.1128/mSphere.01015-20 -
Journal of Global Antimicrobial... Dec 2020The aim of this study was to identify Acinetobacter spp. strains from paediatric patients, to determine their genetic relationship, to detect antibiotic resistance genes...
OBJECTIVES
The aim of this study was to identify Acinetobacter spp. strains from paediatric patients, to determine their genetic relationship, to detect antibiotic resistance genes and to evaluate the role of efflux pumps in antibiotic resistance.
METHODS
A total of 54 non-duplicate, non-consecutive Acinetobacter spp. isolates were collected from paediatric patients. Their genetic relationship, antibiotic resistance profile, efflux pump activity, antibiotic resistance genes and plasmid profile were determined.
RESULTS
The isolates were identified as 24 Acinetobacter haemolyticus, 24 Acinetobacter calcoaceticus-baumannii (Acb) complex and 1 strain each of Acinetobacter junii, Acinetobacter radioresistens, Acinetobacter indicus, Acinetobacter lwoffii, Acinetobacter ursingii and Acinetobacter venetianus. The 24 A. haemolyticus were considered genetically unrelated. One strain was resistant to carbapenems, two to cephalosporins, two to ciprofloxacin and sixteen to aminoglycosides. The antibiotic resistance genes bla (29%), bla (4%), bla (8%), bla (29%), bla (4%), aac(6')-Ig (38%) and the novel variants bla (13%), bla (75%), aac(6')-Iga (4%), aac(6')-Igb (13%) and aac(6')-Igc (42%) were detected. Among 24 Acb complex, 5 were multidrug-resistant, carbapenem-resistant strains carrying bla and bla; they were genetically related and had the same plasmid profile. Other species were susceptible. In some strains of A. haemolyticus and Acb complex, the role of RND efflux pumps was evidenced by a decrease in the MICs for cefotaxime, amikacin and ciprofloxacin in the presence of an efflux pump inhibitor.
CONCLUSIONS
This study identified isolates of A. haemolyticus carrying new β-lactamase variants and shows for the first time the contribution of efflux pumps to antibiotic resistance in this species.
Topics: Acinetobacter; Acinetobacter Infections; Acinetobacter baumannii; Child; Hospitals, Pediatric; Humans; Mexico
PubMed: 32916332
DOI: 10.1016/j.jgar.2020.08.014 -
Huan Jing Ke Xue= Huanjing Kexue May 2020Due to the problems of low nitrogen removal efficiency and unclear electron transfer during biological denitrification treatment of an oligotrophic drinking water...
Due to the problems of low nitrogen removal efficiency and unclear electron transfer during biological denitrification treatment of an oligotrophic drinking water reservoir, the nitrogen removal characteristics, environmental adaptability, and electron transfer during denitrification were systematically studied using the aerobic denitrifier ZMF5, which has efficient nitrogen removal ability. The results showed that:① Strain ZMF5 exhibited efficient heterotrophic nitrification and aerobic denitrification ability, with an ammonia removal rate of 0.211 mg·(L·h) and a nitrate removal rate of 0.236 mg·(L·h), and the nitrification intermediates were not accumulated during the treatment process. ② According to analysis of the nitrogen removal efficiency and growth kinetics of strain ZMF5, the strain can effectively utilize different types of carbon source, and show efficient nitrogen removal efficiency under the conditions of low C/N, low pH, and low temperature. ③ Analysis of nitrogen balance showed that carboxylate compound, compared with carbohydrate, could promote the process of aerobic denitrification and change the nitrogen removal pathway of strain ZMF5, i.e., 38.81% of nitrogen was transformed into gas, higher than the 29.81% for assimilation. ④ Analysis of carbon balance indicated that most carbon sources were used as electron donors in the denitrification process, but fewer electrons were used for nitrate reduction, and with respect to different carbon sources, electron transfer to the nitrate respiratory chain was regulated by different reduction potentials, electron donor abundance, and molecular weight. ZMF5 could be used to control nitrogen pollution in drinking water reservoirs.
Topics: Acinetobacter; Aerobiosis; Carbon; Denitrification; Heterotrophic Processes; Nitrates; Nitrification; Nitrites; Nitrogen
PubMed: 32608852
DOI: 10.13227/j.hjkx.201911201 -
AMB Express Jun 2020Deltamethrin and its major metabolite 3-phenoxybenzoic acid (3-PBA) have caused serious threat to the environment as well as human health, yet little is known about...
Deltamethrin and its major metabolite 3-phenoxybenzoic acid (3-PBA) have caused serious threat to the environment as well as human health, yet little is known about their degradation pathways by bacterial co-cultures. In this study, the growth and degradation kinetics of Acinetobacter junii LH-1-1 and Klebsiella pneumoniae BPBA052 during deltamethrin and 3-PBA degradation were established, respectively. When the inoculum proportion of the strains LH-1-1 and BPBA052 was 7.5:2.5, and LH-1-1 was inoculated 24 h before inoculation of strain BPBA052, 94.25% deltamethrin was degraded and 9.16 mg/L of 3-PBA remained within 72 h, which was 20.36% higher and 10.25 mg/L lesser than that in monoculture of LH-1-1, respectively. And the half-life of deltamethrin was shortened from 38.40 h to 24.58 h. Based on gas chromatography-mass spectrometry, 3-phenoxybenzaldehyde, 1,2-benzenedicarboxylic butyl dacyl ester, and phenol were identified as metabolites during deltamethrin degradation in co-culture. This is the first time that a co-culture degradation pathway of deltamethrin has been proposed based on these identified metabolites. Bioremediation of deltamethrin-contaminated soils with co-culture of strains LH-1-1 and BPBA052 significantly enhanced deltamethrin degradation and 3-PBA removal. This study provides a platform for further studies on deltamethrin and 3-PBA biodegradation mechanism in co-culture, and it also proposes a promising approach for efficient bioremediation of environment contaminated by pyrethroid pesticides and their associated metabolites.
PubMed: 32495133
DOI: 10.1186/s13568-020-01043-1 -
Indian Journal of Medical Microbiology 2019As reports on colistin resistance are slowly emerging from different parts of the world, it is imperative that the clinical microbiology laboratories should generate... (Comparative Study)
Comparative Study
Comparative evaluation of microscan walkaway 96 plus ID/AST system and mikrolatest broth microdilution kit in assessing colistin susceptibility of carbapenem-resistant clinical gram-negative bacterial isolates: Experience from a tertiary care teaching hospital in Rishikesh, Uttarakhand.
CONTEXT
As reports on colistin resistance are slowly emerging from different parts of the world, it is imperative that the clinical microbiology laboratories should generate accurate in vitro colistin susceptibility results.
AIM
The aim is to generate preliminary data on the diagnostic utility of MicroScan WalkAway 96 Plus Identification ID/ Antimicrobial susceptibility testing AST system in determining in vitro colistin susceptibility of carbapenem-resistant clinical Gram-negative bacterial isolates.
SETTINGS AND DESIGN
A pilot study was conducted in a tertiary care teaching hospital located in Rishikesh, Uttarakhand, between May and June 2019.
MATERIALS AND METHODS
Thirty-four carbapenem-resistant Escherichia coli, Pseudomonas aeruginosa and Acinetobacter spp. isolated from various non-repetitive clinical samples during the study period, were subjected to antibiotic susceptibility testing using MicroScan ID/AST system. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry was used to confirm identity of these isolates. Additional colistin susceptibility testing of all test isolates was performed using Mikrolatest minimum inhibitory concentration antibiotic susceptibility testing kit (reference method), which is based on broth micro dilution (BMD) principle.
STATISTICAL ANALYSIS USED
Fisher's exact test.
RESULTS
11.8% (4/34) of the test isolates (100% [2/2] Acinetobacter junii, 10% [1/10] E. coli and 14.3% [1/7] P. aeruginosa respectively) exhibited in vitro colistin resistance by BMD method. Categorical agreement between MicroScan ID/AST system and Mikrolatest kit w. r. t in vitro colistin susceptibility test results was as follows: 71.4% (Acinetobacter baumannii), 85.7% (P. aeruginosa) and 100% (A. junii, A. johnsonii, E. coli and Klebsiella pneumoniae), respectively. Two major errors (MEs) for A. baumannii and one very ME for P. aeruginosa respectively were observed.
CONCLUSIONS
Data generated by this study will be of help to the clinicians who are often faced with the dilemma of treating multi drug resistant infections with limited treatment options.
Topics: Anti-Bacterial Agents; Carbapenem-Resistant Enterobacteriaceae; Carbapenems; Colistin; Drug Resistance, Multiple, Bacterial; Female; Gram-Negative Bacteria; Hospitals, Teaching; Humans; India; Male; Microbial Sensitivity Tests; Middle Aged; Pilot Projects; Tertiary Healthcare
PubMed: 32436871
DOI: 10.4103/ijmm.IJMM_19_437 -
Urology Case Reports Sep 2020is one of more than 50 different species belonging to the genus . This bacterium is rarely reported to cause human infections. Here we described a rare case of , which...
is one of more than 50 different species belonging to the genus . This bacterium is rarely reported to cause human infections. Here we described a rare case of , which grew in urine culture approximately one month after the patient was discharged from the hospital with antibiotics for a urinary tract infection, which caused left obstructing renal calculi requiring nephrostomy tube placement.
PubMed: 32322533
DOI: 10.1016/j.eucr.2020.101209 -
Applied and Environmental Microbiology May 2020Resistance to the "last-resort" antibiotics, such as carbapenems, has led to very few antibiotics being left to treat infections by multidrug-resistant bacteria. Spread...
Resistance to the "last-resort" antibiotics, such as carbapenems, has led to very few antibiotics being left to treat infections by multidrug-resistant bacteria. Spread of carbapenem resistance (CR) has been well characterized for the clinical environment. However, there is a lack of information about its environmental distribution. Our study reveals that CR is present in a wide range of Gram-negative bacteria in the coastal seawater environment, including four phyla, eight classes, and 30 genera. These bacteria were likely introduced into seawater via stormwater flows. Some CR isolates found here, such as , , , , , , and , are further relevant to human health. We also describe a novel metallo-β-lactamase (MBL) for marine isolates with CR, which has likely been horizontally transferred to or In contrast, another MBL of the New Delhi type was likely acquired by environmental isolates from , , or utilizing a plasmid. Our findings add to the growing body of evidence that the aquatic environment is both a reservoir and a vector for novel CR genes. Resistance against the "last-resort" antibiotics of the carbapenem family is often based on the production of carbapenemases, and this has been frequently observed in clinical samples. However, the dissemination of carbapenem resistance (CR) in the environment has been less well explored. Our study shows that CR is commonly found in a range of bacterial taxa in the coastal aquatic environment and can involve the exchange of novel metallo-β-lactamases from typical environmental bacteria to potential human pathogens or vice versa. The outcomes of this study contribute to a better understanding of how aquatic and marine bacteria can act as reservoirs and vectors for CR outside the clinical setting.
Topics: Anti-Bacterial Agents; Aquatic Organisms; Carbapenems; Drug Resistance, Multiple, Bacterial; Fresh Water; Gram-Negative Bacteria; New South Wales
PubMed: 32198174
DOI: 10.1128/AEM.02939-19 -
Journal of Burn Care & Research :... Jan 2020This paper describes the wound microbiology and outcome of using systemic antibiotic prophylaxis (SAP) in mass burn casualties (MBC). The charts of 31 patients (mean...
This paper describes the wound microbiology and outcome of using systemic antibiotic prophylaxis (SAP) in mass burn casualties (MBC). The charts of 31 patients (mean age: 21 years, mean burn area: 42% of the total body surface area) injured in a dust explosion were reviewed for 1 month after the burn. Polymicrobial and rare pathogen wound infections (Acinetobacter junii, Aeromonas sobri, et al) were common in MBC due to sterility breech. Following the use of SAP for 2 to 14 days after admission, there was a reduction in wound infection rate from 45% at week 1 postburn to 10% at week 4. In addition, no blood stream infection occurred in the first week after the burns. Multidrug-resistant Acinetobacter baumannii, Klebsiella pneumoniae, and Candida albicans were the top three wound pathogens cultured. Multidrug-resistant microorganism infections were found in 39% of the patients, and the odds ratios for the these infections in burn patients with more than ≥40% total body surface area and in patients receiving two or more classes of antibiotics were 41.7 (95% confidence interval [CI] = 2.1-810.7, P = .01) and 9.9 (95% CI= 1.0-92.7, P = .04), respectively. Although SAP did not prevent wound or blood stream infections, no mortality occurred in our patients. A randomized controlled study is needed to investigate the impact of SAP on burn mortality in MBC.
Topics: Adolescent; Adult; Anti-Bacterial Agents; Antibiotic Prophylaxis; Burns; Cohort Studies; Explosions; Female; Humans; Male; Mass Casualty Incidents; Taiwan; Wound Infection; Young Adult
PubMed: 31999335
DOI: 10.1093/jbcr/irz077 -
Huan Jing Ke Xue= Huanjing Kexue Aug 2019Due to the problems of traditional biological nitrogen and phosphorus removal, including long process duration and high infrastructural and operational costs, the...
Due to the problems of traditional biological nitrogen and phosphorus removal, including long process duration and high infrastructural and operational costs, the simultaneous nitrogen and phosphorus removal capabilities, influencing factors and kinetic characteristics were systematically studied using the heterotrophic nitrifier NP1 which possesses efficient simultaneous nitrogen and phosphorus removal ability. The results showed that strain NP1 exhibited efficient heterotrophic nitrification ability with a maximum ammonia removal rate of 99.12%. Furthermore, only small amounts of nitrification intermediates were accumulated during the reaction process. Strain NP1 also adapted well to higher ammonia nitrogen loading. In addition, strain NP1 had efficient aerobic denitrification characteristics, and could utilize nitrite and nitrate for growth and metabolism, achieving a maximum removal rate of 91.40% and 95.10%, respectively. The heterotrophic nitrification process of strain NP1 was accompanied by simultaneous phosphorus accumulation, and the appropriate ratio of nitrogen to phosphorus was beneficial for the simultaneous removal of nitrogen and phosphorus. When the ratio of nitrogen to phosphorus was 5:1, the maximum ammonia nitrogen and phosphate removal rates reached 99.21% and 88.35%, respectively. The bacterial growth process of stain NP1 matched the Logistic model (>0.99), and the nitrogen and phosphate degradation conformed to the Compertz model (>0.99). The maximum conversion rates of nitrogen and phosphate () obtained by model fitting were in the order ammonia>nitrate>nitrite, and lag time (0) was in the order nitrate>nitrite>ammonia. According to the analysis of the degradation kinetics of the matrix and the removal rate of nitrogen and phosphorus, the optimal conditions were found to be sodium succinate, C/N=10, =30℃, and =160 r·min.
Topics: Acinetobacter; Aerobiosis; Denitrification; Heterotrophic Processes; Kinetics; Nitrification; Nitrites; Nitrogen; Phosphorus; Water Purification
PubMed: 31854780
DOI: 10.13227/j.hjkx.201901208 -
Journal of Medical Entomology May 2020Pediculosis capitis caused by Pediculus humanus capitis (De Geer) is endemic all over the world, and children are mostly affected, particularly those living in...
Pediculosis capitis caused by Pediculus humanus capitis (De Geer) is endemic all over the world, and children are mostly affected, particularly those living in overcrowded institutions. Several studies have shown that P. h. capitis carried human pathogenic bacteria, suggesting the potential role of head lice in the transmission of pathogens to humans. In this study, we determined the genetic diversity of head lice collected from welfare homes sheltering underprivileged children by using DNA barcoding and demonstrated the presence of Acinetobacter spp., Serratia marcescens, and Staphylococcus aureus in head lice, which have never been investigated before in Malaysia. Cox1 DNA barcoding identified the head lice, P. h. capitis collected from welfare homes across two geographical areas of Peninsular Malaysia as belonging to clades A, B, and D. Acinetobacter bacteria: Acinetobacter guillouiae, Acinetobacter junii, Acinetobacter baumannii, and Acinetobacter nosocomialis were detected in head lice belonging to clades A and also D. In addition, DNA from S. marcescens and S. aureus were also detected in both clades A and D. To our knowledge, this is the first report on the genetic diversity of head lice in Malaysia through DNA barcoding, as well as the first to provide molecular evidence on the type of bacteria occurring in head lice in Malaysia. It is anticipated that the DNA barcoding technique used in this study will be able to provide rapid and accurate identification of arthropods, in particular, medically important ectoparasites.
Topics: Animals; Bacteria; DNA Barcoding, Taxonomic; Genetic Variation; Housing; Humans; Lice Infestations; Malaysia; Pediculus; Social Class
PubMed: 31828310
DOI: 10.1093/jme/tjz234