Bovine subclinical mastitis-associated methicillin-resistant Staphylococcus aureus, selective genotyping and antimicrobial susceptibility profile of the isolates in Kurdistan province of Iran

Background and Objectives: Staphylococcus aureus is frequently involved in bovine subclinical mastitis worldwide. Besides, the methicillin-resistant S. aureus (MRSA) carrier state of animals is a matter of worrisome. This study aimed to evaluate the frequency of MRSA, discriminatory geno-analysis and antibiotic resistance scheme of the strains isolated from bovine subclinical mastitis in Kurdistan province of Iran. Materials and Methods: A total of 283 samples were collected and analyzed for S. aureus phenotypically and molecularly. SCCmec and coa types, and pvl gene were evaluated using polymerase chain reaction (PCR). Finally, the restriction fragment length polymorphism (RFLP) patterns of coa types and the antimicrobial susceptibility profile of the isolates were assessed. Results: Among the 95 isolates of S. aureus, 11 (11.57%) strains were recognized as MRSA. Six, one, and four SCCmec types represented for IVa, IVc, and V were determined, respectively, among which an individual IVa and V determinant harboured pvl gene. Restriction digestion products of 490 bp, 680 bp, and 730 bp of coa bands were generated. Tobramycin, mupirocin, fusidic acid, clindamycin, and chloramphenicol were the most effective drugs against the MRSA isolates. Conclusion: The detrimental involvement of S. aureus in bovine subclinical mastitis is proved herein. Besides, the contribution of MRSA and potential contamination of milk and dairy products with the bacterium may impose a serious public health risk. This demands serious and long-lasting efforts to control the infection. The results may be effective in the implementation of accurate controlling strategies.

Diversity of Nonribosomal Peptide Synthetase Genes in the AnticancerProducing Actinomycetes Isolated from Marine Sediment in Indonesia

Marine actinomycetes is a group of bacteria that is highly potential in producing novel bioactivecompound. It has unique characteristics and is different from other terrestrial ones. Extreme environmentalcondition is suspected to lead marine actinomycetes produce different types of bioactive compoundfound previously. The aim of this study was to explore the presence and diversity of NRPS genes in 14anticancer-producing actinomycetes isolated from marine sediment in Indonesia. PCR amplificationand restriction fragment analysis of NRPS genes with HaeIII from 14 marine actinomycetes were doneto assess the diversity of NRPS genes. Genome mining of one species of marine actinomycetes (strainGMY01) also was employed towards this goal. The result showed that NRPS gene sequence diversity in 14marine actinomycetes could be divided into 4 groups based on NRPS gene restriction patterns. Analysisof 16S rRNA gene sequences of representatives from each group showed that all isolates belong to genusof Streptomyces. Genome mining result showed that strain GMY01 harboring 10 different NRPS geneclusters that encode secondary metabolites, as pure NRPS or hybrid between NRPS and other compounds.These results indicated that marine actinomycetes having a high potential to be developed as source ofanticancer drugs development.

High Prevalence of Panton-Valentine Leukocidin (PVL) Genes in Nosocomial-AcquiredStaphylococcus aureusIsolated from Tertiary Care Hospitals in Nepal

Methicillin-resistantStaphylococcus aureus(MRSA) carrying the important virulence determinant, Panton-Valentine leukocidin (PVL), is an emerging infectious pathogen associated with skin and soft tissue infections as well as life-threatening invasive diseases. In carrying out the first PVL prevalence study in Nepal, we screened 73 nosocomial isolates ofS. aureusfrom 2 tertiary care Nepali hospitals and obtained an overall PVL-positivity rate of 35.6% among the hospital isolates: 26.1% of MRSA and 51.9% of methicillin sensitiveS. aureus(MSSA) isolates were found to be positive for the PVL genes. PVL prevalence was not associated with a specific (i) infection site, (ii) age group, or (iii) hospital of origin. It was found to be positively associated with heterogeneous MRSA (73.3%) compared to homogeneous MRSA (3.2%) and MSSA (51.9%); negatively associated with multiresistant MRSA (22%) compared to nonmultiresistant MRSA (60%) and MSSA (51.9%); and positively associated with macrolide-streptogramin B resistance (93.8%) compared to macrolide-lincosamide-streptogramin B resistance (0%) and no-resistance (45.8%) types. Macrolide-streptogramin B resistance was confirmed by the presence ofmsr(A) gene. Restriction pattern analyses provided evidence to support the circulation of a limited number of clones of PVL-positive MRSA, arguing for the adaptability of these isolates to a hospital setting.

Mesophilic Fermentation of Renewable Biomass: Does Hydraulic Retention Time Regulate Methanogen Diversity?

ABSTRACT The present long-term study (about 1,100 days) monitored the diversity of methanogens during the mesophilic, anaerobic digestion of beet silage. Six fermentor samples were analyzed by ribosomal RNA gene restriction analysis, fluorescence in situ hybridization, and fluorescence microscopy. Hydrogenotrophic methanogens dominated within the population in all samples analyzed. Multidimensional scaling revealed that a rapid decrease in hydraulic retention time resulted in increased species richness, which in turn led to slightly higher CH4 yields.

Anaerobic Digestion of Renewable Biomass: Thermophilic Temperature Governs Methanogen Population Dynamics

ABSTRACT Beet silage and beet juice were digested continuously as representative energy crops in a thermophilic biogas fermentor for more than 7 years. Fluorescence microscopy of 15 samples covering a period of 650 days revealed that a decrease in temperature from 60°C to 55°C converted a morphologically uniform archaeal population (rods) into a population of methanogens exhibiting different cellular morphologies (rods and coccoid cells). A subsequent temperature increase back to 60°C reestablished the uniform morphology of methanogens observed in the previous 60°C period. In order to verify these observations, representative samples were investigated by amplified rRNA gene restriction analysis (ARDRA) and fluorescence in situ hybridization (FISH). Both methods confirmed the temperature-dependent population shift observed by fluorescence microscopy. Moreover, all samples investigated demonstrated that hydrogenotrophic Methanobacteriales dominated in the fermentor, as 29 of 34 identified operational taxonomic units (OTUs) were assigned to this order. This apparent discrimination of acetoclastic methanogens contradicts common models for anaerobic digestion processes, such as anaerobic digestion model 1 (ADM1), which describes the acetotrophic Euryarchaeota as predominant organisms.

Antimicrobial Susceptibility of Mycoplasma pneumoniae Isolates and Molecular Analysis of Macrolide-Resistant Strains from Shanghai, China

ABSTRACT Fifty-three Mycoplasma pneumoniae strains were isolated from pediatric patients in Shanghai, China, from October 2005 to February 2008. Of 53 clinical isolates, 44 (83%) were resistant to erythromycin (MICs of >128 μg/ml for all 44 strains), azithromycin, and clarithromycin. All macrolide-resistant M. pneumoniae strains harbored an A-to-G transition mutation at position 2063 in 23S rRNA genes. Forty-five (85%) clinical isolates were classified into the P1 gene restriction fragment length polymorphism type I, and six (11%) were type II.