Tetralone Derivatives From a Deep-Sea-Derived Fungus Cladosporium Sp. HDN17-58

One new tetralone derivative, named aladothalen (1), and one known biogenetically related compound, (3 S,4 S)−3,4,8-trihydroxy-3,4-dihydronaphthalen-1(2 hours)-one (2), were isolated from a deep-sea-derived-fungal Cladosporium sp. HDN17-58. Their structures, including absolute configurations, were elucidated by extensive NMR, MS, and ECD analyses. Compound 1 exhibited potent bacteriostatic activity against Bacillus cereus, Mycobacterium phlei and methicillin-resistant coagulase-negative Staphylococci, with a MIC value of 25 µM.

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Antibacterial Polyketides from Antarctica Sponge-Derived Fungus Penicillium sp. HDN151272

Marine Drugs ◽

10.3390/md18020071 ◽

2020 ◽

Vol 18 (2) ◽

pp. 71 ◽

Cited By ~ 2

Author(s):

Mudassir Shah ◽

Chunxiao Sun ◽

Zichao Sun ◽

Guojian Zhang ◽

Qian Che ◽

...

Keyword(s):

Antibacterial Activity ◽

Absolute Configuration ◽

Spectroscopic Data ◽

Coagulase Negative Staphylococci ◽

Methicillin Resistant ◽

Penicillium Sp ◽

Mycobacterium Phlei ◽

The Absolute

Three new polyketides, ketidocillinones A–C (1–3), were discovered from the extract of an Antarctica sponge-derived fungus Penicillium sp. HDN151272. All the structures were deduced by spectroscopic data, including NMR and HRESIMS. The absolute configuration of compound 3 was established by using ECD calculation. Compounds 1−3 can be slowly oxidized to quinone form when exposed to air. Ketidocillinones B and C (2 and 3) exhibited potent antibacterial activity against Pseudomonas aeurigenosa, Mycobacterium phlei, and MRCNS (methicillin-resistant coagulase-negative staphylococci) with MIC values ranging from 1.56 to 25.00 µg/mL.

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Nasopharyngeal Carriage of Methicillin-Resistant Staphylococcus aureus (MRSA) among Sickle Cell Disease (SCD) Children in the Pneumococcal Conjugate Vaccine Era

Infectious Disease Reports ◽

10.3390/idr13010022 ◽

2021 ◽

Vol 13 (1) ◽

pp. 191-204

Author(s):

Nicholas T. K. D. Dayie ◽

Deborah N. K. Sekoh ◽

Fleischer C. N. Kotey ◽

Beverly Egyir ◽

Patience B. Tetteh-Quarcoo ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Sickle Cell Disease ◽

Conjugate Vaccine ◽

Sickle Cell ◽

Pneumococcal Conjugate Vaccine ◽

Diffusion Method ◽

Nasopharyngeal Carriage ◽

Cell Disease ◽

Coagulase Negative Staphylococci ◽

Methicillin Resistant

The aim of this cross-sectional study was to investigate Staphylococcus aureus nasopharyngeal carriage epidemiology in relation to other nasopharyngeal bacterial colonizers among sickle cell disease (SCD) children about five years into pneumococcal conjugate vaccine 13 (PCV-13) introduction in Ghana. The study involved bacteriological culture of nasopharyngeal swabs obtained from 202 SCD children recruited from the Princess Marie Louise Children’s Hospital. S. aureus isolates were identified using standard methods and subjected to antimicrobial susceptibility testing using the Kirby-Bauer disc diffusion method. Cefoxitin-resistant S. aureus isolates were screened for carriage of the mecA, pvl, and tsst-1 genes using multiplex polymerase chain reaction. The carriage prevalence of S. aureus was 57.9% (n = 117), and that of methicillin-resistant S. aureus (MRSA) was 3.5% (n = 7). Carriage of the mecA, pvl, and tsst-1 genes were respectively demonstrated in 20.0% (n = 7), 85.7% (n = 30), and 11.4% (n = 4) of the cefoxitin-resistant S. aureus isolates. PCV-13 vaccination (OR = 0.356, p = 0.004) and colonization with coagulase-negative staphylococci (CoNS) (OR = 0.044, p < 0.0001) each protected against S. aureus carriage. However, none of these and other features of the participants emerged as a determinant of MRSA carriage. The following antimicrobial resistance rates were observed in MRSA compared to methicillin-sensitive S. aureus: clindamycin (28.6% vs. 4.3%), erythromycin (42.9% vs. 19.1%), tetracycline (100% vs. 42.6%), teicoplanin (14.3% vs. 2.6%), penicillin (100% vs. 99.1%), amoxiclav (28.6% vs. 3.5%), linezolid (14.3% vs. 0.0%), ciprofloxacin (42.9% vs. 13.9%), and gentamicin (42.9% vs. 13.0%). The proportion of S. aureus isolates that were multidrug resistant was 37.7% (n = 46). It is concluded that S. aureus was the predominant colonizer of the nasopharynx of the SCD children, warranting the continuous monitoring of this risk group for invasive S. aureus infections.

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In Vitro activity of a Novel Benzoquinolizine Antibiotic, Levonadifloxacin (WCK 771) against Blood Stream Gram-Positive Isolates from a Tertiary Care Hospital

Journal of Laboratory Physicians ◽

10.1055/s-0040-1720944 ◽

2020 ◽

Vol 12 (03) ◽

pp. 230-232

Author(s):

Dhruv Mamtora ◽

Sanjith Saseedharan ◽

Ritika Rampal ◽

Prashant Joshi ◽

Pallavi Bhalekar ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Tertiary Care Hospital ◽

Tertiary Care ◽

Blood Stream ◽

Tolerability Profile ◽

Care Hospital ◽

Coagulase Negative Staphylococci ◽

Gram Positive ◽

Methicillin Resistant

Abstract Background Blood stream infections (BSIs) due to Gram-positive pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) are associated with high mortality ranging from 10 to 60%. The current anti-MRSA agents have limitations with regards to safety and tolerability profile which limits their prolonged usage. Levonadifloxacin and its oral prodrug alalevonadifloxacin, a novel benzoquinolizine antibiotic, have recently been approved for acute bacterial skin and skin structure infections including diabetic foot infections and concurrent bacteremia in India. Methods The present study assessed the potency of levonadifloxacin, a novel benzoquinolizine antibiotic, against Gram-positive blood stream clinical isolates (n = 31) collected from January to June 2019 at a tertiary care hospital in Mumbai, India. The susceptibility of isolates to antibacterial agents was defined following the Clinical and Laboratory Standard Institute interpretive criteria (M100 E29). Results High prevalence of MRSA (62.5%), quinolone-resistant Staphylococcus aureus (QRSA) (87.5%), and methicillin-resistant coagulase-negative staphylococci (MR-CoNS) (82.35%) were observed among bacteremic isolates. Levonadifloxacin demonstrated potent activity against MRSA, QRSA, and MR-CoNS strains with significantly lower minimum inhibitory concentration MIC50/90 values of 0.5/1 mg/L as compared with levofloxacin (8/32 mg/L) and moxifloxacin (2/8 mg/L). Conclusion Potent bactericidal activity coupled with low MICs support usage of levonadifloxacin for the management of BSIs caused by multidrug resistant Gram-positive bacteria.

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Methicillin-Resistant Staphylococcus aureus (MRSA) Infection of Diabetic Foot Ulcers at a Tertiary Care Hospital in Accra, Ghana

Pathogens ◽

10.3390/pathogens10080937 ◽

2021 ◽

Vol 10 (8) ◽

pp. 937

Author(s):

Ramzy B. Anafo ◽

Yacoba Atiase ◽

Nicholas T. K. D. Dayie ◽

Fleischer C. N. Kotey ◽

Patience B. Tetteh-Quarcoo ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Multidrug Resistance ◽

Teaching Hospital ◽

Diabetic Foot ◽

Foot Ulcer ◽

Foot Ulcers ◽

Diabetic Foot Ulcers ◽

Coagulase Negative Staphylococci ◽

Methicillin Resistant ◽

Mrsa Infection

Aim: This study investigated the spectrum of bacteria infecting the ulcers of individuals with diabetes at the Korle Bu Teaching Hospital in Accra, Ghana, focusing on Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA), with respect to their prevalence, factors predisposing to their infection of the ulcers, and antimicrobial resistance patterns. Methodology: This cross-sectional study was conducted at The Ulcer Clinic, Department of Surgery, Korle Bu Teaching Hospital, involving 100 diabetic foot ulcer patients. The ulcer of each study participant was swabbed and cultured bacteriologically, following standard procedures. Antimicrobial susceptibility testing was done for all S. aureus isolated, using the Kirby-Bauer method. Results: In total, 96% of the participants had their ulcers infected—32.3% (n = 31) of these had their ulcers infected with one bacterium, 47.9% (n = 46) with two bacteria, 18.8% (n = 18) with three bacteria, and 1.0% (n = 1) with four bacteria. The prevalence of S. aureus and MRSA were 19% and 6%, respectively. The distribution of the other bacteria was as follows: coagulase-negative Staphylococci (CoNS) (54%), Escherichia coli (24%), Pseudomonas spp. (19%), Citrobacter koseri and Morganella morgana (12% each), Klebsiella oxytoca (11%), Proteus vulgaris (8%), Enterococcus spp. (6%), Klebsiella pneumoniae (5%), Proteus mirabilis and Enterobacter spp. (4%), Klebsiella spp. (2%), and Streptococcus spp. (1%). The resistance rates of S. aureus decreased across penicillin (100%, n = 19), tetracycline (47.4%, n = 9), cotrimoxazole (42.1%, n = 8), cefoxitin (31.6%, n = 6), erythromycin and clindamycin (26.3% each, n = 5), norfloxacin and gentamicin (15.8% each, n = 3), rifampicin (10.5%, n = 2), linezolid (5.3%, n = 1), and fusidic acid (0.0%, n = 0). The proportion of multidrug resistance was 47.4% (n = 9). Except for foot ulcer infection with coagulase-negative Staphylococci, which was protective of S. aureus infection of the ulcers (OR = 0.029, p = 0.001, 95% CI = 0.004–0.231), no predictor of S. aureus, MRSA, or polymicrobial ulcer infection was identified. Conclusions: The prevalence of S. aureus and MRSA infection of the diabetic foot ulcers were high, but lower than those of the predominant infector, coagulase-negative Staphylococci and the next highest infecting agent, E. coli. Diabetic foot ulcers’ infection with coagulase-negative Staphylococci protected against their infection with S. aureus. The prevalence of multidrug resistance was high, highlighting the need to further intensify antimicrobial stewardship programmes.

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Comparative activity of linezolid and other new agents against methicillin-resistant Staphylococcus aureus and teicoplanin-intermediate coagulase-negative staphylococci

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/48.6.911 ◽

2001 ◽

Vol 48 (6) ◽

pp. 911-913 ◽

Cited By ~ 25

Author(s):

C. Betriu

Keyword(s):

Staphylococcus Aureus ◽

Methicillin Resistant Staphylococcus Aureus ◽

Coagulase Negative Staphylococci ◽

New Agents ◽

Methicillin Resistant ◽

Comparative Activity

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Can the Xpert MRSA/SA BC assay be used as an antimicrobial stewardship tool? A prospective assay validation and descriptive impact assessment study in a South African setting

BMC Infectious Diseases ◽

10.1186/s12879-021-05857-7 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Kessendri Reddy ◽

Andrew Whitelaw

Keyword(s):

Bloodstream Infection ◽

South African ◽

Antimicrobial Stewardship ◽

Antibiotic Use ◽

Rapid Identification ◽

Western Cape ◽

Beta Lactams ◽

Coagulase Negative Staphylococci ◽

Methicillin Resistant ◽

Potential Impact

Abstract Background Positive blood cultures showing Gram positive cocci in clusters signifies either Staphylococcus aureus or the less-virulent coagulase-negative staphylococci. Rapid identification and methicillin susceptibility determination with the Xpert MRSA/SA BC assay can improve management of S. aureus bloodstream infection and reduce inappropriate antibiotic use. Methods We prospectively evaluated the Xpert MRSA/SA BC assay in comparison with culture, on samples referred to our laboratory in the Western Cape, South Africa. We interviewed attending clinicians upon culture result availability, to assess antibiotic choices and estimate potential impact of the assay. Results Of the 231 samples included, there was 100% concordance between the Xpert MRSA/SA BC assay and culture (methicillin-resistant S. aureus 15/15, methicillin-susceptible S. aureus 42/42, coagulase-negative staphylococci 170/170). Time to final result could be reduced by approximately 30 h with the assay. Of the 178 patients with adequate antibiotic history, optimisation of antistaphylococcal therapy could have occurred more than 1 day sooner in 68.9% with S. aureus bloodstream infection (31/45, 95% CI 53.2–81.4%). Six of the 11 patients with methicillin-resistant S. aureus bloodstream infection (54.5%) could have received anti-MRSA cover sooner. Fifty-four days of antibiotic therapy could have been spared, equating to 0.3 days (95% CI, 0.2–0.4) saved per patient, driven by broad-spectrum beta-lactams (32 days, in 18.0% of the cohort). Conclusion This assay has potential as an antimicrobial stewardship tool; costing and impact on clinical outcome in patients with S. aureus bloodstream infection should be assessed.

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Species-Specific Sensitivity of Coagulase-Negative Staphylococci to Single Antibiotics and Their Combinations

Polish Journal of Microbiology ◽

10.33073/pjm-2011-022 ◽

2011 ◽

Vol 60 (2) ◽

pp. 155-161 ◽

Cited By ~ 4

Author(s):

GRAŻYNA SZYMAŃSKA ◽

MAGDALENA SZEMRAJ ◽

ELIGIA M. SZEWCZYK

Keyword(s):

University Hospital ◽

Hospital Environment ◽

Beta Lactam ◽

Coagulase Negative Staphylococci ◽

Methicillin Resistant ◽

Beta Lactam Antibiotics ◽

Resistant Strains ◽

Staphylococcus Hominis ◽

Species Specific

The activity of beta-lactam antibiotics (oxacillin, cloxacillin, cephalotin), vancomycin, gentamicin and rifampicin applied in vitro individually and in combination against 37 nosocomial methicillin-resistant strains of coagulase-negative staphylococci (CNS) was assessed to demonstrate the heterogeneity of this group of bacteria and estimate the chance of the efficacy of such therapy. The strains belonged to four species: Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus cohnii, Staphylococcus hominis. They originated from a hospital environment and from the skin of medical staff of the intensive care unit of a paediatric ward at a university hospital. All strains were methicillin-resistant, according to CLSI standards, but individual strains differed in MIC(ox) values. Susceptibility to other tested antibiotics was also characteristic for the species. The increased susceptibility to antibiotics in combinations, tested by calculating the fractional inhibitory concentration (FIC) index, concerned 26 out of 37 investigated strains and it was a feature of a particular species. Combinations of vancomycin and cephalotin against S. epidermidis and oxacillin with vancomycin were significant, as well as cephalotin and rifampicin in growth inhibition of multiresistant S. haemolyticus strains.

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Outbreak of Mupirocin-Resistant Staphylococci in a Hospital in Warsaw, Poland, Due to Plasmid Transmission and Clonal Spread of Several Strains

Journal of Clinical Microbiology ◽

10.1128/jcm.37.9.2781-2788.1999 ◽

1999 ◽

Vol 37 (9) ◽

pp. 2781-2788 ◽

Cited By ~ 31

Author(s):

Tomasz A. Łe˛ski ◽

Marek Gniadkowski ◽

Anna Skoczyńska ◽

Elz˙bieta Stefaniuk ◽

Krzysztof Trzciński ◽

...

Keyword(s):

Resistance Mechanisms ◽

Hospital Environment ◽

Coagulase Negative Staphylococci ◽

Large Hospital ◽

Methicillin Resistant ◽

Inappropriate Use ◽

Clonal Spread ◽

High Level ◽

Almost All ◽

Level Resistance

An outbreak of mupirocin-resistant (MuR) staphylococci was investigated in two wards of a large hospital in Warsaw, Poland. Fifty-three MuR isolates of Staphylococcus aureus, S. epidermidis, S. haemolyticus, S. xylosus, and S. capitis were identified over a 17-month survey which was carried out after introduction of the drug for the treatment of skin infections. The isolates were collected from patients with infections, environmental samples, and carriers; they constituted 19.5% of all staphylococcal isolates identified in the two wards during that time. Almost all the MuR isolates were also resistant to methicillin (methicillin-resistant S. aureus and methicillin-resistant coagulase-negative staphylococci). Seven of the outbreak isolates expressed a low-level-resistance phenotype (MuL), whereas the remaining majority of isolates were found to be highly resistant to mupirocin (MuH). The mupA gene, responsible for the MuH phenotype, has been assigned to three different polymorphic loci among the strains in the collection analyzed. The predominant polymorph, polymorph I (characterized by a mupA-containingEcoRI DNA fragment of about 16 kb), was located on a specific plasmid which was widely distributed among the entire staphylococcal population. All MuR S. aureus isolates were found to represent a single epidemic strain, which was clonally disseminated in both wards. The S. epidermidis population was much more diverse; however, at least four clusters of closely related isolates were identified, which suggested that some strains of this species were also clonally spread in the hospital environment. Six isolates of S. epidermidis were demonstrated to express the MuL and MuH resistance mechanisms simultaneously, and this is the first identification of such dual MuR phenotype-bearing strains. The outbreak was attributed to a high level and inappropriate use of mupirocin, and as a result the dermatological formulation of the drug has been removed from the hospital formulary.

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