Phage vB_BveM-Goe7 represents a new genus in the subfamily Bastillevirinae.

Bacillus velezensis FZB42 is a Gram-positive, endospore-forming rhizobacterium that is associated with plant roots and promotes plant growth. It was used as host to isolate phage vB_BveM-Goe7 (Goe7). Goe7 exhibits a Myoviridae morphology with a contractile tail and an icosahedral head. Its genome is 158,674 bp in size and contains 5137-bp-long terminal repeats (LTRs). It also contains five tRNA-encoding genes and 251 coding DNA sequences (CDS), of which 65 were annotated. The adsorption constant of Goe7 is 6.1 ± 0.24 × 10-8 ml/min, with a latency period of 75 min and a burst size of 114 particles per burst. A BLASTn sequence comparison against the non-redundant nucleotide database of NCBI revealed that Goe7 is most similar to Bacillus subtilis phage vB_BsuM-Goe3.

Nonstable Staphylococcus aureus Small-Colony Variants Are Induced by Low pH and Sensitized to Antimicrobial Therapy by Phagolysosomal Alkalinization.

BACKGROUND: Staphylococcus aureus-infected patients treated with antibiotics that are effective in vitro often experience relapse of infection because the bacteria hide in privileged locations. These locations include abscesses and host cells, which contain low-pH compartments and are sites from which nonstable S. aureus small-colony variants (SCVs) are frequently recovered. METHODS: We assessed the effect of low pH on S. aureus colony phenotype and bacterial growth, using in vitro and in vivo models of long-term infection. RESULTS: We showed that low pH induced nonstable SCVs and nonreplicating persisters that are capable of regrowth. Within host cells, S. aureus was located in phagolysosomes, a low-pH compartment. Therapeutic neutralization of phagolysosomal pH with ammonium chloride, bafilomycin A1, or the antimalaria drug chloroquine reduced SCVs in infected host cells. In a systemic mouse infection model, treatment with chloroquine also reduced SCVs. CONCLUSIONS: Our results show that the acidic environment favors formation of nonstable SCVs, which reflect the SCVs found in clinics. They also provide evidence that treatment with alkalinizing agents, together with antibiotics, may provide a novel translational strategy for eradicating persisting intracellular reservoirs of staphylococci. This approach may also be extended to other intracellular bacteria.

Clonality and antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus at the University Hospital Zurich, Switzerland between 2012 and 2014.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is a global epidemic threat. The aim of this study was to determine which globally known MRSA lineages are currently present at our tertiary care hospital in Switzerland, a hospital with low MRSA prevalence. In light of the increasing prevalence of multi drug resistance including vancomycin resistance we also assessed antibiotic susceptibilities. METHODS: The 146 MRSA strains collected over two years (March 2012 until February 2014) at the University Hospital Zurich, Switzerland, were analyzed by PFGE analysis of SmaI digests in combination with spa-typing. In addition, representative isolates were analyzed by multi locus sequence typing (MLST). Susceptibilities to eight antibiotics were assessed using the Kirby-Bauer disc diffusion method. RESULTS: Isolates showed resistance to erythromycin (48%), ciprofloxacin (43%), clindamycin (31%), tetracycline (22%), and gentamicin (16%). All isolates were susceptible to vancomycin, 95% were susceptible to sulfamethoxazole/trimethoprim and rifampicin, respectively. PFGE analysis revealed 22 different patterns, with four major patterns that accounted for 53.4% of all MRSA isolates, and seven sporadic patterns. Spa typing revealed 50 different spa types with the predominant types being t008 (14%), t002 (10%), and t127 (9%). 82% of the MRSA isolates could be assigned to six clonal complexes (CCs) namely CC1 (10%), CC5 (23%), CC8 (18%), CC22 (17%), CC30 (11%), and CC45 (3%) based on spa-types, PFGE patterns, and MLST. Two isolates could not be typed by either PFGE analysis or spa-typing and three isolates had spa-types that have not yet been described. CONCLUSIONS: The combination of the two typing methods was more discriminatory as compared to the use of a single method. Several of the lineages that are predominant in Europe are present in our hospital. Resistances to antibiotics have decreased in comparison to a study conducted between 2004 and 2006.

USA300 methicillin-resistant Staphylococcus aureus in Zurich, Switzerland between 2001 and 2013.

USA300 methicillin-resistant Staphylococcus aureus (MRSA) is the most prevalent MRSA in the United States of America (USA) and a global epidemic threat. We investigated the prevalence of USA300 at a tertiary care hospital in Zurich, Switzerland, where all MRSA strains have been collected and PFGE typed since 1992. These strains were retrospectively compared to the PFGE pattern of USA300 strain JE2. Isolates with a respective PFGE pattern were spa-typed and tested for the presence of the arginine catabolic mobile element (ACME) arc gene cluster and Panton-Valentine Leucocidin (PVL) genes. The first MRSA strain with a USA300 PFGE pattern was isolated in 2001 from a patient visiting from the USA. USA300 strains represented between 0% (in 2002) and 9.2% (in 2012) of all MRSA isolates in our hospital. We identified various USA300 subtypes based on either the PFGE pattern, the spa-type or absence of either the PVL genes or ACME arc gene cluster. All the USA300 strains including the variants (n=47) accounted for 5.6% of all MRSA isolates typed between 2001 and 2013 and reached a maximum of 14.5% in 2009. They predominantly caused skin and soft tissue infections (74.4%). In conclusion, even though USA300 has been present in our hospital for over twelve years it has not become the predominant MRSA clone like in the USA. However, in light of the global burden of USA300, care must be taken to further contain the spread of this lineage and of MRSA in general in our hospital.