Multilocus sequence analysis reveals genetic diversity in Staphylococcus aureus isolate of goat with mastitis persistent after treatment with enrofloxacin

Staphylococcus aureus is one of the main bacterial agents responsible for cases of mastitis in ruminants, playing an important role in the persistence and chronicity of diseases treated with antimicrobials. Using the multilocus sequence typing technique, network approaches and study of the population diversity of microorganisms, we performed analyzes of S. aureus (ES-GPM) isolated from goats with persistent mastitis (GPM). The most strains of ES-GPM were categorically different phylogenetically from the others and could be divided into two lineages: one with a majority belonging to ES-GPM and the other to varied strains. These two lineages were separated by 27 nuclear polymorphisms. The 43 strains comprised 22 clonal complexes (CCs), of which the ES-GPM strains were present in CC133, CC5 and a new complex formed by the sequence type 4966. The genetic diversity of some alleles showed be greater diversity and polymorphism than others, such as of the aroE and yqiL genes less than glpF gene. In addition, the sequences ES-GPM to the arc gene and glpF alleles showed the greatest number of mutations for ES-GPM in relation to non-ES-GPM. Therefore, this study identified genetic polymorphisms characteristic of S. aureus isolated from milk of goats diagnosed with persistent mastitis after the failed treatment with the antibiotic enrofloxacin. This study may help in the future to identify and discriminate this agent in cases of mastitis, and with that, the most appropriate antibiotic treatment can be performed in advance of the appearance of persistent mastitis caused by the agent, reducing the chances of premature culling and animal suffering.

In Vitro Time-Kill of Common Ocular Pathogens with Besifloxacin Alone and in Combination with Benzalkonium Chloride

Background: Besifloxacin ophthalmic suspension 0.6% (w/v%) contains benzalkonium chloride (BAK) as a preservative. We evaluated the in vitro time-kill activity of besifloxacin, alone and in combination with BAK, against common bacteria implicated in ophthalmic infections. Methods: The activity of besifloxacin (100 µg/mL), BAK (10, 15, 20, and 100 µg/mL), and combinations of besifloxacin and BAK were evaluated against isolates of Staphylococcus epidermidis (n = 4), Staphylococcus aureus (n = 3), Haemophilus influenzae (n = 2), and Pseudomonas aeruginosa (n = 2) in time-kill experiments of 180 min duration. With the exception of one S. aureus isolate, all of the staphylococcal isolates were methicillin- and/or ciprofloxacin-resistant; one P. aeruginosa isolate was ciprofloxacin-resistant. The reductions in the viable colony counts (log10 CFU/mL) were plotted against time, and the differences among the time–kill curves were evaluated using an analysis of variance. Areas-under-the-killing-curve (AUKCs) were also computed. Results: Besifloxacin alone demonstrated ≥3-log killing of P. aeruginosa (<5 min) and H. influenzae (<120 min), and approached 3-log kills of S. aureus. BAK alone demonstrated concentration-dependent killing of S. epidermidis, S. aureus and H. influenzae, and at 100 µg/mL produced ≥3-log kills in <5 min against these species. The addition of BAK (10, 15, and 20 µg/mL) to besifloxacin increased the rate of killing compared to besifloxacin alone, with earlier 3-log kills of all species except P. aeruginosa and a variable impact on S. aureus. The greatest reductions in AUKC were observed among H. influenzae (8-fold) and S. epidermidis (≥5-fold). Similar results were found when the isolates were evaluated individually by their resistance phenotype. Conclusions: In addition to confirming the activity of 100 µg/mL BAK as a preservative in the bottle, these data suggest that BAK may help besifloxacin to achieve faster time-kills on-eye in the immediate timeframe post-instillation before extensive dilution against bacterial species implicated in ophthalmic infections, including drug-resistant S. epidermidis. Greater killing activity may help prevent resistance development and/or help treat resistant organisms.

Phänotypische Antibiotikaresistenzen von Bakterienisolaten aus Zier-, Zoo- und falknerisch gehaltenen Greifvögeln

Zusammenfassung Gegenstand und Ziel Die Prävalenz von antibiotikaresistenten Bakterien bei Zier-, Zoo- und falknerisch gehaltenen Greifvögeln ist noch weitgehend unbekannt. Daher sollten retrospektiv Antibiogramme schnellwachsender aerober Bakterienarten ausgewertet werden. Material und Methoden Im Auswertungszeitraum von 2007 bis 2016 standen 1036 Antibiogramme zur Verfügung. Die Bakterienisolate stammten vorzugsweise aus Süddeutschland und von 811 Vögeln aus 20 zoologischen Ordnungen (am häufigsten Papageienvögel [61,8 %] und Sperlingsvögel [14,5 %]) sowie aus Proben von klinischen Patienten und Sektionsmaterial. Die phänotypische In-vitro-Empfindlichkeit wurde mittels Plattendiffusionstest ermittelt. Ergebnisse Die meisten Antibiogramme lagen für E. coli (n = 386 Isolate) vor, gefolgt von Staphylococcus (S.). aureus (n = 150), Enterobacter cloacae (n = 122), Klebsiella pneumoniae (n = 86) und Pseudomonas aeruginosa (n = 64). Resistenzen gegen mindestens einen antibiotischen Wirkstoff zeigten 53,1 % der E. coli-Isolate, dabei am häufigsten gegen Doxycyclin (50,3 %) und Ampicillin (46,1 %). Bei 78,0 % der S. aureus-Isolate und bei 95,9 % der Enterococcus faecalis-Isolate wurden Resistenzen gegenüber mindestens einem Wirkstoff nachgewiesen. Multiresistenzen (Resistenz gegenüber ≥ 3 Antibiotikagruppen) traten bei 37,3 % der Isolate von S. aureus auf. Bei Isolaten von Zier- und Greifvögeln wurden höhere Resistenzraten festgestellt als bei Isolaten von Zoovögeln und bei Papageienvögeln höhere Resistenzraten als bei Sperlingsvögeln. Im Untersuchungszeitraum zeigte sich bei E. coli ein tendenzieller Anstieg der Resistenzrate für Fluorchinolone (Minimum von 0 % im Jahr 2013 und Maximum von 27,3 % im Jahr 2015) und bei S. aureus eine tendenzielle Abnahme der Resistenzraten für Tetrazykline (Maximum von 39,4 % im Jahr 2007 und Minimum von 0 % in den Jahren 2014 und 2015). Schlussfolgerung und klinische Relevanz Die Resistenzsituation von Bakterien aus Zier-, Zoo- und falknerisch gehaltenen Greifvögeln ist als problematisch zu bewerten und verdeutlicht die Wichtigkeit der Empfindlichkeitsprüfung für eine gewissenhafte Therapie. Im Fall einer Infektion mit S. aureus bei Zier-, Zoo- oder falknerisch gehaltenen Greifvögeln kann es zu einem Therapienotstand kommen.

Aktivitas Antibiotik terhadap Biofilm Staphylococcus aureus Isolat Preputium Sapi Aceh (Antibiotic Activities To Staphylococcus aureus Biofilms Of Aceh Cattle Preputium Isolate)

Biofilm is one of parameters for determining pathogenic pathways of a bacterium. Bacterial virulence activities can be attenuated by antibiotics with inhibiting biofilm. The aim of this study was to examine the characteristics and activities of antibiotics against the biofilm of Stapylococcus aureus isolate which taken from Aceh cattle prepuce. The study was exploratory and experimental, using a Completely Randomized Design (RAL) factorial pattern using three types of antibiotics, three concentrations and replications. Antibiotics were tetracycline, oxytetracycline and phosphomycin with concentrations of 10%, 20% and 30% (mg/mL), respectively. Therefore, the aim of this study was to examine the characteristics and activities of antibiotics to the biofilm of Stapylococcus aureus from Aceh cattle prepuce isolate. U-bottom polystyrene 96 wells microplate and Nutrient Broth (NB) medium were used to biofilm. Bacterial while biofilm was stained on crystals violet 1%. Optical Density (OD) of biofilm were λ 595 nm. Data were analyzed by using Analysis Of Variance (ANOVA). The results showed that the activity of Staphylococcus aureus was moderately positive, i.e 2,667cell/μL. It showed that antibiotics and concetrations have significant effect (P<0.05) to inhibit biofilm staphylococcus aureus. In additioon, tetracycline 30% (mg / mL) has the best ability to inhibit biofilms from 52,18% to 1,262 cell/μL. Based on that fact, it can be concluded that the virulence of Staphylococcus aureus was moderate positive to be false positive. Keywords: biofilm, antibiotics, Staphylococcus aureus, cows aceh. Abstrak Biofilm merupakan salah satu parameter untuk menentukan jalur patogenisitas suatu bakteri. Antibiotik dapat melemahkan aktivitas virulensi bakteri dengan menghambat pembentukan biofilm. Penelitian ini bertujuan untuk melihat karaksteristik dan aktivitas antibiotik terhadap biofilm Stapylococcus aureus isolat preputium sapi Aceh. Penelitian bersifat eksplorasi dan eksperimental, menggunakan Rancangan Acak Lengkap (RAL) pola faktorial dengan menggunakan tiga jenis antibiotik, tiga konsentrasi dan tiga kali ulangan. Antibiotik yang digunakan adalah tetrasiklin, oksitetrasiklin dan fosfomisin dengan konsentrasi masing-masing 10%, 20% dan 30% (mg/mL). Pengujian biofilm dilakukan pada media Nutrient Broth (NB), menggunakan mikroplat U-bottom polystyrene 96 wells. Pewarnaan biofilm menggunakan kristal violet 1%. Optical Density (OD) biofilm dibaca pada λ 595 nm. Data hasil penelitian dianalisis dengan menggunakan Analysis Of Variance (ANOVA). Hasil penelitian menunjukkan aktivitas virulensi Staphylococcus aureus isolat preputium sapi Aceh berdasarkan karaksteristik biofilm tergolong positif moderat, yaitu 2,667cell/µL. Uji Biofilm menunjukkan jenis dan konsentrasi antibiotik berpengaruh secara nyata (P<0,05) terhadap daya hambat biofilm Staphylococcus aureus isolat preputium sapi Aceh. Tetrasiklin 30% (mg/mL) mempunyai kemampuan paling baik menghambat pembentukan biofilm Staphylococcus aureus isolat preputium sapi Aceh sebesar 52,18% menjadi 1,262 cell/µL, sehingga aktivitas virulensi Staphylococcus aureus isolat preputium sapi Aceh berdasarkan karaksteristik biofilm dari positif moderat menjadi positif palsu. Kata Kunci: biofilm, antibiotik, Staphylococcus aureus, sapi aceh.

Complete Genome Sequence of a Staphylococcus aureus Isolate from a Nasopharyngeal Swab from a Mine Worker in South Africa

Here, we present the complete genome sequence of Staphylococcus aureus NP66, isolated from a South African mine worker.

Antibiotic Profile of Staphylococcus aureus on Table Eggs from Ezrad Farms in Iwo Area of Osun State

Surface swabs of the table eggs were carried out using sterile swab sticks. These were inoculated on Mannitol Salt Agar and incubated at 37°C for 24 hours. The isolates obtained were morphologically and biochemically characterized. 62% of the isolates obtained were identified as Staphylococcus aureus. 0.5 McFarland standard of each Staphylococcus aureus isolate was subjected to antibiotic susceptibility test on Muller Hinton Agar using the disc diffusion method. Antibiotic susceptibility was determined by observing and measuring clear zones in millimetres. The antibiogram pattern of Staphylococcus aureus on the surface of table eggs from Ezrad farms located in Iwo, Osun State was investigated. Staphylococcus aureus isolates were 100% resistant to Augmentin and Cloxacillin while resistance to Ceftazidime, Erythromycin, Gentamycin, Ofloxacin, Cefuroxime and Ceftriaxone were at 96%, 89%, 86%, 82%, 75% and 57% respectively. This study shows high resistance of Staphylococcus aureus isolated from eggshells to antibiotics which could pose a serious health problem.