INFLUENCE OF BACTERIAL ADHERENCE TO INTRAVASCULAR CATHETERS ON IN-VITRO ANTIBIOTIC SUSCEPTIBILITY

ABSTRACT Recent outbreaks of cardiac surgery-associated Mycobacterium chimaera infections have highlighted the importance of species differentiation within the Mycobacterium avium complex and pointed to a lack of antibiotic susceptibility data for M. chimaera. Using the MGIT 960/EpiCenter TB eXiST platform, we have determined antibiotic susceptibility patterns of 48 clinical M. chimaera isolates and 139 other nontuberculous mycobacteria, including 119 members of the M. avium complex and 20 Mycobacterium kansasii isolates toward clofazimine and other drugs used to treat infections with slow-growing nontuberculous mycobacteria (NTM). MIC50, MIC90, and tentative epidemiological cutoff (ECOFF) values for clofazimine were 0.5 mg/liter, 1 mg/liter, and 2 mg/liter, respectively, for M. chimaera. Comparable values were observed for other M. avium complex members, whereas lower MIC50 (≤0.25 mg/liter), MIC90 (0.5 mg/liter), and ECOFF (1 mg/liter) values were found for M. kansasii. Susceptibility to clarithromycin, ethambutol, rifampin, rifabutin, amikacin, moxifloxacin, and linezolid was in general similar for M. chimaera and other members of the M. avium complex, but increased for M. kansasii. The herein determined MIC distributions, MIC90, and ECOFF values of clofazimine for M. chimaera and other NTM provide the basis for the definition of clinical breakpoints. Further studies are needed to establish correlation of in vitro susceptibility and clinical outcome.

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Evaluation of Antibiotic Treatment against “Candidatus Helicobacter suis” in a Mouse Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.49.11.4530-4535.2005 ◽

2005 ◽

Vol 49 (11) ◽

pp. 4530-4535 ◽

Cited By ~ 11

Author(s):

A. Hellemans ◽

A. Decostere ◽

F. Haesebrouck ◽

R. Ducatelle

Keyword(s):

Mouse Model ◽

Antibiotic Susceptibility ◽

Susceptibility Testing ◽

Bacterial Dna ◽

Urease Test ◽

Slaughter Pigs ◽

Cessation Of Treatment

ABSTRACT “Helicobacter heilmannii” (proposed name) type 1 colonizes the human stomach. It has been shown to be identical to“ Candidatus Helicobacter suis,” a Helicobacter species colonizing the stomachs of >60% of slaughter pigs. This bacterium has not been isolated in vitro until now. Antibiotic susceptibility testing of “Candidatus Helicobacter suis” has not been carried out so far. For the present study, a mouse model was adopted to evaluate the antibiotic susceptibility of this organism. Mice infected with“ Candidatus Helicobacter suis” were treated with amoxicillin and omeprazole, a therapy which is used to treat H. heilmannii infections in humans. Two different isolates of“ Candidatus Helicobacter suis” were tested. The excretion of bacterial DNA was assessed during treatment, using PCR on fecal samples. At the end of the experiment, 8 days after the cessation of treatment, the presence of infection was evaluated using a urease test and a PCR test on stomach samples. A marked decrease in the excretion of bacterial DNA was observed a few days after the onset of treatment, and the level remained low until the end of the experiment. A difference in susceptibility between the two“ Candidatus Helicobacter suis” isolates was pointed out. The in vivo mouse model infected with“ Candidatus Helicobacter suis” will be useful for further screening of potential therapeutic regimens.

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Machine Learning Analyses on Data including Essential Oil Chemical Composition and In Vitro Experimental Antibiofilm Activities against Staphylococcus Species

Molecules ◽

10.3390/molecules24050890 ◽

2019 ◽

Vol 24 (5) ◽

pp. 890 ◽

Cited By ~ 17

Author(s):

Alexandros Patsilinakos ◽

Marco Artini ◽

Rosanna Papa ◽

Manuela Sabatino ◽

Mijat Božović ◽

...

Keyword(s):

Machine Learning ◽

Opportunistic Pathogen ◽

Genetic Mutation ◽

Bacterial Biofilm ◽

Chemical Components ◽

Chemical Compositions ◽

Biofilm Production ◽

Major Interest ◽

Intravascular Catheters

Biofilm resistance to antimicrobials is a complex phenomenon, driven not only by genetic mutation induced resistance, but also by means of increased microbial cell density that supports horizontal gene transfer across cells. The prevention of biofilm formation and the treatment of existing biofilms is currently a difficult challenge; therefore, the discovery of new multi-targeted or combinatorial therapies is growing. The development of anti-bioﬁlm agents is considered of major interest and represents a key strategy as non-biocidal molecules are highly valuable to avoid the rapid appearance of escape mutants. Among bacteria, staphylococci are predominant causes of biofilm-associated infections. Staphylococci, especially Staphylococcus aureus (S. aureus) is an extraordinarily versatile pathogen that can survive in hostile environmental conditions, colonize mucous membranes and skin, and can cause severe, non-purulent, toxin-mediated diseases or invasive pyogenic infections in humans. Staphylococcus epidermidis (S. epidermidis) has also emerged as an important opportunistic pathogen in infections associated with medical devices (such as urinary and intravascular catheters, orthopaedic implants, etc.), causing approximately from 30% to 43% of joint prosthesis infections. The scientific community is continuously looking for new agents endowed of anti-biofilm capabilities to fight S. aureus and S epidermidis infections. Interestingly, several reports indicated in vitro efficacy of non-biocidal essential oils (EOs) as promising treatment to reduce bacterial biofilm production and prevent the inducing of drug resistance. In this report were analyzed 89 EOs with the objective of investigating their ability to modulate bacterial biofilm production of different S. aureus and S. epidermidis strains. Results showed the assayed EOs to modulated the biofilm production with unpredictable results for each strain. In particular, many EOs acted mainly as biofilm inhibitors in the case of S. epidermidis strains, while for S. aureus strains, EOs induced either no effect or stimulate biofilm production. In order to elucidate the obtained experimental results, machine learning (ML) algorithms were applied to the EOs’ chemical compositions and the determined associated anti-biofilm potencies. Statistically robust ML models were developed, and their analysis in term of feature importance and partial dependence plots led to indicating those chemical components mainly responsible for biofilm production, inhibition or stimulation for each studied strain, respectively.

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In Vitro Antibiotic Susceptibility of Shigella Isolated from U. S. Forces in South Vietnam

Military Medicine ◽

10.1093/milmed/132.12.975 ◽

1967 ◽

Vol 132 (12) ◽

pp. 975-977

Author(s):

E. M. K. Vaichulis ◽

H. G. Arm ◽

C. W. Halverson ◽

N. C. LaChapelle

Keyword(s):

Antibiotic Susceptibility ◽

South Vietnam

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