Including Methicillin Resistant Strains Research Articles

Antimicrobial Susceptibility Profiles and Molecular Characterisation of Staphylococcus aureus from Pigs and Workers at Farms and Abattoirs in Zambia.

Pigs have been shown to be a reservoir for recently emerging livestock-associated Staphylococcus aureus (LA-SA), including methicillin resistant strains in many countries worldwide. However, there is sparse information about LA-SA strains circulating in Zambia. This study investigated the prevalence, phenotypic and genotypic characteristics of S. aureus from pigs and workers at farms and abattoirs handling pigs in Lusaka Province of Zambia. A total of 492 nasal pig swabs, 53 hand and 53 nasal human swabs were collected from farms and abattoirs in selected districts. Standard microbiological methods were used to isolate and determine antimicrobial susceptibility patterns of S. aureus. Polymerase Chain Reaction was used to confirm the species identity and detect antimicrobial resistance and virulence genes of isolates, whereas genetic diversity was evaluated using spa typing. Overall prevalence of S. aureus was 33.1%, 37.8% for pigs and 11.8% for humans. The isolates were resistant to several antibiotics with resistance ranging from 18% to 98% but were all susceptible to vancomycin. Typical LA-SA spa types were detected. The presence of plasmid mediated resistance genes such as tetM (12.8%), other resistance determinants and immune evasion cluster genes among the isolates is of great public health concern. Thus, continuous surveillance of S. aureus using a “One health” approach is warranted to monitor S. aureus infections and spread of antimicrobial resistance.

Polyphenolic profile, antibacterial activity and brine shrimp toxicity of leaf extracts from six Tunisian spontaneous species

The aim of this study was to investigate the polyphenolic profile and biological properties of leaves acetonic extracts from six Tunisian spontaneous plants of Marrubium vulgare L., Rhus tripartita (Ucria) D.C., Hernaria fontanesii J. Gay subsp. fontanesii, Ziziphus lotus L., Plantago ovata Forsk., Thymelaea hirsuta (L.) Endl. Bioassay-guided and HPLC-PDA-ESI-MS procedures demonstrated that R. tripartita contained the highest amount of phenolic compounds (1475.1 µg/g), followed by Z. lotus (1087.8 µg/g) and P. ovata (1027.6 µg/g). Interestingly, in R. tripartita myricetin‐3-O-galactoside turned out to be the most abundant one. The plant extracts showed antimicrobial efficacy against Listeria monocytogenes, Staphylococcus aureus and S. epidermidis including methicillin resistant strains; no activity was detected against Gram-negative bacteria. R. tripartita revealed the best MIC and MBC values and caused significant decrease of S. aureus biofilm. Both R. tripartita and Z. lotus did not display any toxicity against Artemia salina Leach (LC50 > 1000 μg/mL).

Antibiotic Sensitivity Tests of Staphylococcus aureus Isolated from Different Clinical Specimens

The importance of Staphylococcus aureus as a persistent nosocomial and community acquired pathogen has become a global health concern. It has a remarkable capability of evolving different mechanisms of resistance to most antimicrobial agents. of the present study is to establish the incidence of S. aureus in different clinical specimens with theirantibiotic sensitivity pattern to various antibiotics in this locality.Sixty five consecutive isolates of S. aureus obtained from various clinical specimens between January and April 2016 sent to the Medical Microbiology Laboratory Department of Al-Hilla Teaching Hospital was confirmed by standard bacteriological procedures. An antibiotic sensitivity pattern was carried out by disc diffusion method. The female sex has the highest rate of infection (57%) compared to males (43%). Urine and wound infection had the highest frequency of S. aureus isolates (35.3) and (26.1) respectively in the study. The results show that S. aureus bacterium mostly sensitive to amikacin AK and rifampicin RA (65.7%) and (58.6%). S. aureus shows resistance to vancomycin and tetracycline antibiotics mostly (66%) and (64%)The results of the present study show that the aminoglycosides are effective in the management of Staphylococcus aureus infections including methicillin resistant strains in this environment.

Prevalence and molecular characteristics of Staphylococcus aureus, including methicillin resistant strains, isolated from bulk can milk and raw milk products in pastoral communities of South-West Uganda

BackgroundStaphylococcus aureus strains are now regarded as zoonotic agents. In pastoral settings where human-animal interaction is intimate, multi-drug resistant microorganisms have become an emerging zoonotic issue of public health concern. The study of S. aureus prevalence, antimicrobial resistance and clonal lineages in humans, animals and food in African settings has great relevance, taking into consideration the high diversity of ethnicities, cultures and food habits that determine the lifestyle of the people. Little is known about milk carriage of methicillin resistant S. aureus strains (MRSA) and their virulence factors in Uganda. Here, we present the prevalence of MRSA in bulk can milk and raw milk products in pastoral communities of south-west Uganda. We also present PFGE profiles, spa-types, as well as frequency of enterotoxins genes.MethodsS. aureus was identified by the coagulase test, susceptibility testing by the Kirby-Bauer disc diffusion and E-test methods and MRSA by detection of the mecA gene and SCCmec types. The presence of Panton – Valentine Leucocidin (PVL) genes and staphylococcal enterotoxins was determined by PCR, while genotyping was by PFGE and spa typing.ResultsS. aureus were isolated from 30/148 (20.3%) milk and 11/91(12%) sour milk samples. mecA gene carriage, hence MRSA, was detected in 23/41 (56.1%) of the isolates, with 21 of the 23 (91.3%) being SCCmec type V; while up to 30/41 (73.2%) of the isolates were resistant to tetracycline. Only five isolates carried the PVL virulence gene, while PFGE typing revealed ten clusters (ranging from two seven isolates each) that comprised 83% of the sample, and only eight isolates with unique pulsotypes. The largest PFGE profile (E) consisted of seven isolates while t7753, t1398, and t2112 were the most common spa-types. Thirty seven of the 41 strains (90.2%) showed at least one of the eight enterotoxin genes tested, with sem 29 (70.7%), sei 25 (61%) and seg 21 (51.2%) being the most frequently observed genes.ConclusionThis is the first study to demonstrate MRSA and enterotoxin genes in raw milk and its products in Uganda. The fact that over 90% of the isolates carried at least one gene encoding enterotoxins shows a high risk of spread of foodborne diseases through milk in this setting.

Antibacterial in vitro effects of preparations from Anthroposophical Medicine.

BackgroundMedications from Anthroposophical Medicine (AM) are clinically used for the treatment of infections within a whole medical system but have not yet been evaluated regarding antibacterial effects. The aims of this study was to investigate antibacterial activity of AM medications in cell culture.MethodsScreening of AM drug registers for preparations used to treat any kind of infection and being available in dilutions ≤ D2 and without alcoholic content. Selected medications were screened for antimicrobial activity against Bacillus subtilis, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa using the agar diffusion method. For antimicrobial active preparations growth kinetics (drop plate method) and minimal inhibitory concentrations (MIC, macrodilution method) were determined.ResultsThirty-three preparations matched the selection criteria and were chosen for own experiments. One of them (Berberis Decoctum D2) exhibited bactericidal activities against Bacillus subtilis and Staphylococcus aureus, including methicillin resistant strains. The MIC could be determined as 5 mg/ml. The effects could be related to the content of berberine in the extract. No activity towards gram-negative bacteria was found. The other tested extracts had no antibacterial effects.ConclusionBerberis Decoctum D2 which is used in AM to treat infections exhibits bactericidal effects on Staphylococcus aureus, including methicillin resistant strains.

Global analysis of the impact of linezolid onto virulence factor production in S. aureus USA300

The translation inhibitor linezolid is an antibiotic of last resort against Gram-positive pathogens including methicillin resistant strains of the nosocomial pathogen Staphylococcus aureus. Linezolid is reported to inhibit production of extracellular virulence factors, but the molecular cause is unknown. To elucidate the physiological response of S. aureus to linezolid in general and the inhibition of virulence factor synthesis in particular a holistic study was performed.Linezolid was added to exponentially growing S. aureus cells and the linezolid stress response was analyzed with transcriptomics and quantitative proteomics methods. In addition, scanning and transmission electron microscopy experiments as well as fluorescence microscopy analyses of the cellular DNA and membrane were performed.As previously observed in studies on other translation inhibitors, S. aureus adapts its protein biosynthesis machinery to the reduced translation efficiency. For example the synthesis of ribosomal proteins was induced. Also unexpected results like a decline in the amount of extracellular and membrane proteins were obtained. In addition, cell shape and size changed after linezolid stress and cell division was diminished. Finally, the chromosome was condensed after linezolid stress and lost contact to the membrane. These morphological changes cannot be explained by established theories. A new hypothesis is discussed, which suggests that the reduced amount of membrane and extracellular proteins and observed defects in cell division are due to the disintegration of transertion complexes by linezolid.

Factores relacionados con la colonización por Staphylococcus aureus

Staphylococcus aureus tiene gran capacidad para colonizar la piel y las mucosas de los seres humanos y de diferentes animales. Varios estudios evidencian el papel de dicha colonización en la patogénesis y la epidemiología de las infecciones causadas por S. aureus. Se ha demostrado que los portadores nasales constituyen una fuente importante de propagación de la bacteria; una amplia proporción de las infecciones estafilocócicas invasivas asociadas al cuidado de la salud son de origen endógeno, y la colonización por cepas de S. aureus resistentes a meticilina (SARM), aún mal entendida, origina mayores complicaciones. La importancia de la colonización se ha definido con más profundidad en ambientes hospitalarios, pero recientemente se han hecho estudios en la comunidad con resultados contradictorios sobre la relación colonización-infección. En esta revisión se presentan algunas características relevantes del proceso de colonización por S. aureus, incluyendo las cepas de SARM, y se consideran los factores humanos y del microorganismo que influyen en él. Asimismo, se hace una revisión de los estudios colombianos al respecto.

Staphylococcus haemolyticus prophage ΦSH2 endolysin relies on cysteine, histidine-dependent amidohydrolases/peptidases activity for lysis ‘from without’

Staphylococcus aureus is an important pathogen, with methicillin-resistant (MRSA) and multi-drug resistant strains becoming increasingly prevalent in both human and veterinary clinics. S. aureus causing bovine mastitis yields high annual losses to the dairy industry. Conventional treatment of mastitis by broad range antibiotics is often not successful and may contribute to development of antibiotic resistance. Bacteriophage endolysins present a promising new source of antimicrobials. The endolysin of prophage ΦSH2 of Staphylococcus haemolyticus strain JCSC1435 (ΦSH2 lysin) is a peptidoglycan hydrolase consisting of two catalytic domains (CHAP and amidase) and an SH3b cell wall binding domain. In this work, we demonstrated its lytic activity against live staphylococcal cells and investigated the contribution of each functional module to bacterial lysis by testing a series of deletion constructs in zymograms and turbidity reduction assays. The CHAP domain exhibited three-fold higher activity than the full length protein and optimum activity in physiological saline. This activity was further enhanced by the presence of bivalent calcium ions. The SH3b domain was shown to be required for full activity of the complete ΦSH2 lysin. The full length enzyme and the CHAP domain showed activity against multiple staphylococcal strains, including MRSA strains, mastitis isolates, and CoNS.

Antibiotic sensitivity pattern of <i>Staphylococcus aureus</i> from clinical isolates in a tertiary health institution in Kano, Northwestern Nigeria

The importance of Staphylococcus aureus as a persistent nosocomial and community acquired pathogen has become a global health concern. It has a remarkable capability of evolving different mechanisms of resistance to most antimicrobial agents. The aim of the present study is to establish the incidence of S. aureus in clinical specimens and its antibiotic sensitivity pattern to various antibiotics in this locality. One hundred and fifty consecutive isolates of S. aureus obtained from various clinical specimens between January and December 2009 sent to the Medical Microbiology Laboratory Department of Aminu Kano Teaching Hospital (AKTH) were confirmed by standard bacteriological procedures. Antibiotic sensitivity pattern was carried out by disc diffusion method. The age group with the highest number of isolates was (0-10) yrs while wound infection had the highest frequency of S. aureus isolates (30.7%) in the study. Males (62.0%) were more infected than females (38.0%). The sensitivity pattern of S. aureus to the following antibiotics; Gentamicin, Amoxycillin/clavulanate, Streptomycin, Cloxacillin, Erythromycin, Chloramphenicol, Cotrimoxazole, Tetracycline, Penicillin, Ciprofloxacin, Ofloxacin, Levofloxacin, Ceftriaxone, Amoxycillin and vancomycin were 92.4%, 63.0%, 44.2%, 35.8%, 52.4%, 61.9%, 15.5%, 31.2%, 7.1%, 78.9%, 76.6%, 100%, 71.4%, 30.7% and 100% respectively. Methicillin resistant isolates were sensitive to Levofloxacin 93.7% and Ofloxacin 68.7%. The results of the present study show that the fluoroquinolones are effective in the management of Staphylococcus aureus infections including methicillin resistant strains in this environment.

Antimicrobial activity and phenolic content of natural site and micropropagated Limonium avei (De Not.) Brullo & Erben plant extracts

This study reported the antimicrobial activity and phenolic content of natural site and micropropagated Limonium avei (De Not.) Brullo & Erben inflorescences. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ethanolic extracts were determined according to the Clinical Laboratory Standards Institute guidelines. Individual phenolic acids and flavonoids were detected by a high performance liquid chromatography (HPLC-DAD) method. The samples showed a comparable antimicrobial activity, although the natural site extract possessed the lower MIC values. The best activity was detected against Gram-positive bacteria, such as Staphylococcus aureus including methicillin resistant strains (MIC and MBC values ranging from 7.81 to 62.50 µg mL−1 and from 500 to 2000 µg mL−1 respectively). In contrast, a low activity was found on Gram-negative bacteria and Candida albicans. The HPLC-DAD analysis revealed ten phenolic acids and four flavonoids with a major amount of m-coumaric acid, naringin and quercetin in the natural site extract.

SASP gene delivery: A novel antibacterial approach

Antibiotic resistance is a global problem, and with bacteria having developed resistance to all approved antibacterial agents there is a growing need for innovative solutions. Phico Therapeutics has developed a new class of antibacterial agent, a platform technology called SASPject. SASPject comprises modified, disabled bacterial viruses (bacteriophages) injecting a gene encoding an antibacterial protein, SASP, into target bacteria. SASP, or Small, Acid-soluble Spore Protein(s), inactivate bacterial DNA in a non-sequence-specific manner so their activity is unaffected by DNA mutations. Selected pathogens can be targeted, avoiding the normal flora. A Staphylococcus aureus-targeted SASPject, PT1.2, developed for the nasal decolonization of S. aureus, including methicillin-resistant (MRSA) strains, is expected to complete phase I in 2009. SASPject PT1.2 shows good in vitro activity against a wide range of diverse clinical S. aureus isolates, including MRSA strains. A systemic SASPject PT1.2, and SASPjects targeted against Clostridium difficile and multidrug-resistant Gram-negative organisms are in development. The SASPject technology could represent a new paradigm in antibacterial therapeutics.