Successful Treatment of Brevibacterium Bacteremia Solely With Antimicrobial Therapy.

Brevibacterium is a large genus that is not often involved in pathogenesis, however, since 1991 there have been several case reports of Brevibacterium-associated illness, most often due to bacteremia in the setting of an immunocompromised patient with a central venous catheter (CVC). Here we detail the case of an elderly woman with many comorbidities and a peripherally inserted central catheter (PICC) line for over four years, who presented with septic shock and Brevibacterium bacteremia. In nearly all previous cases of Brevibacterium bacteremia it was thought to be due to a CVC which was removed as part of the treatment in conjunction with antibiotics. In this case, the patient was treated with empiric antibiotics and her blood cultures cleared within 48 hours without catheter removal or antibiotic-lock therapy. The clinical outcome was favorable at 50 days follow-up.

Panton valentine leukocidin (PVL) toxin positive MRSA strains isolated from companion animals.

Methicillin-resistant Staphylococcus aureus (MRSA) is a highly pathogenic multiple-drug resistant (MDR) microorganism that has recently become more prevalent in the community. It has been found that MRSA strains can also contain genes that encode the panton valentine leukocidin toxin (PVL). The PVL toxin has been shown to be responsible for many of the severe clinical symptoms of infection with MRSA, such as furunculosis, severe necrotizing pneumonia, and necrotic lesions of the skin and soft tissues. The aim of this study was to determine the presence of the S. aureus PVL toxin genes (lukS-PV and lukF-PV) in MRSA strains isolated from companion animals. Eleven MRSA isolates, from a total of 23 tested, were shown to possess the mecA gene and the PVL toxin genes. Pulsed-field gel electrophoresis showed that the 11 PVL toxin positive MRSA strains were highly clonal.

Vancomycin for the treatment of methicillin-resistant staphylococcal and enterococcal infections in 15 horses.

We retrospectively reviewed the cases of 15 foals and adult horses in which vancomycin was used, alone or in combination with an aminoglycoside, to treat methicillin-resistant staphylococcal and enterococcal infections. Signalment, presenting complaint, history (including history of treatment for the current complaint), results of bacterial culture and antimicrobial susceptibility testing, treatment, and outcome were reviewed. The average vancomycin dosage was 7.5 mg/kg q8h, administered by intravenous infusion over 30 min. The infection resolved in all 7 horses with soft tissue infections and in 6 of the 8 horses with infections involving a bone or a joint, or both. No adverse effects of vancomycin therapy were noted. Although the number of cases is small, our findings suggest that vancomycin, alone or in combination with an aminoglycoside, is safe and effective for the treatment of resistant staphylococcal and enterococcal infections in horses and foals. However, owing to the importance of staphylococci and enterococci in human medicine and the problems with emerging resistance, we recommend that the use of vancomycin in horses be limited to cases in which culture and susceptibility results clearly indicate that this agent is likely to be effective and in which there is no reasonable alternative.

The role of disinfectant resistance of Salmonella enterica serotype enteritidis in recurring infections in Pennsylvania egg quality assurance program monitored flocks.

The Pennsylvania egg quality assurance program (PEQAP) has made major gains in the reduction of Salmonella enterica serotype enteritidis (S. enteritidis). However, S. enteritidis continues to be a major food safety concern for the commercial egg laying industry. Despite intensive control efforts through PEQAP, some commercial egg layer houses still remain positive for S. enteritidis. The primary objective of this study was to determine whether S. enteritidis isolates obtained from historically environmentally S. enteritidis-positive houses were resistant to commonly used disinfectants. Archived S. enteritidis isolates (environmental, rodent, or egg) were compared with recently obtained isolates from the environment, rodents, or eggs from the same S. enteritidis-positive house. In addition, the isolates were compared with archived isolates from those premises that appeared to have eliminated S. enteritidis from their layer facilities. The official methods of the use-dilution analysis of the Association of Official Analytical Chemists were used to evaluate each disinfectant product. Two phenolic, one quaternary ammonium, and one combination product containing quaternary ammonium and formaldehyde were evaluated, in addition to one sodium hypochlorite detergent. All products diluted according to the manufacturers' recommendations killed the S. enteritidis isolates in this test system. There was no difference in susceptibility or resistance to the disinfectants used between the isolates from those facilities that remained S. enteritidis-positive and those that appeared to have eliminated S. enteritidis from their facility.

Survival of Salmonella enterica serovar Newport in manure and manure-amended soils.

Salmonella enterica serovar Newport has undergone a rapid epidemic spread in dairy cattle. This provides an efficient mechanism for pathogen amplification and dissemination into the environment through manure spreading on agricultural land. The objective of this study was to determine the survival characteristics of Salmonella serovar Newport in manure and manure-amended soils where the pathogen may be amplified. A multidrug-resistant (MDR) Salmonella serovar Newport strain and a drug-susceptible (DS) strain, both bovine isolates, were inoculated into dairy manure that was incubated under constant temperature and moisture conditions alone or after being mixed with sterilized or nonsterilized soil. Salmonella serovar Newport concentrations increased by up to 400% in the first 1 to 3 days following inoculation, and a trend of steady decline followed. With manure treatment, a sharp decline in cell concentration occurred after day 35, possibly due to microbial antagonism. For all treatments, decreases in Salmonella serovar Newport concentrations over time fit a first-order kinetic model. Log reduction time was 14 to 32 days for 1 log(10), 28 to 64 days for 2 log(10), and 42 to 96 days for 3 log(10) declines in the organisms' populations from initially inoculated concentrations. Most-probable-number monitoring data indicated that the organisms persisted for 184, 332, and 405 days in manure, manure-amended nonsterilized soil, and manure-amended sterilized soil, respectively. The MDR strain and the DS strain had similar survival patterns.

Detection of a bla(SHV) extended-spectrum {beta}-lactamase in Salmonella enterica serovar Newport MDR-AmpC.

Salmonella enterica serovar Newport MDR-AmpC expressing TEM-1b and extended-spectrum beta-lactamase SHV-12 was isolated from affected animals during an outbreak of salmonellosis that led to a 3-month closure of one of the largest equine hospitals in the United States.

Environmental Survey by Manure Drag Sampling for Salmonella enteritidis in Chicken Layer Houses.

The Salmonella enteritidis Pilot Project (SEPP) was started in April 1992 as a cooperative effort between federal and state agencies, university laboratories, and the poultry industry in Pennsylvania to identify on-farm management practices which would reduce the S. enteritidis threat to public health. The SEPP evolved into the Pennsylvania Egg Quality Assurance Program (PEQAP) in 1994. This program uses many production practices and testing protocols outlined in the SEPP. A survey was conducted in 1995 to help evaluate the effectiveness of the program in reducing the prevalence of S. enteritidis in layer flocks. Forty-seven egg laying houses that had been in the SEPP since 1992 were evaluated in 1995 for the presence of S. enteritidis in the environment. Six of 47 houses (13%) were found positive for S. enteritidis on the basis of data collected by manure drag sampling, whereas in 1992 18 of the 47 houses (38%) had been positive for S. enteritidis . The percentage of S. enteritidis -positive samples declined from 21% in 1992 to 3.2% in 1995. This survey provides some evidence that the on-farm risk-reduction management practices identified in the SEPP and subsequently incorporated into the PEQAP have reduced S. enteritidis infections in Pennsylvania flocks.

Molecular characterization of cephalosporin-resistant Salmonella enterica serotype Newport isolates from animals in Pennsylvania.

Multidrug-resistant (MDR) strains of Salmonella enterica serotype Newport have been described for many years. However, the recognition of Newport strains with resistance to cephalosporin antibiotics is more recent. Plasmid-mediated CMY-2 AmpC beta-lactamases have been identified in Salmonella in the United States, and the bla(CMY-2) gene has been shown to be present in Salmonella serotype Newport. This organism is currently undergoing epidemic spread in both animals and humans in the United States, and this is to our knowledge the first description of the molecular epidemiology of this Salmonella strain in animals. Forty-two isolates were included in this study. All isolates were characterized by pulsed-field gel electrophoresis, plasmid analysis, and antibiogram. Four pulsed-field profiles with XbaI were observed. Plasmid analyses showed that although the majority of isolates harbored a single plasmid of 140 kb, this plasmid was not identical in all strains. All isolates showed the presence of the bla(CMY) gene by PCR. Integrons were detected in 16 of the 42 isolates; a fragment of approximately 1,000 bp, amplified with the intI-F and aadAI-R primers, confirmed the presence of the aadAI gene cassette within an integron in these 16 isolates. The potential for coselection of the bla(CMY) gene, if located on an MDR replicon, may not be dependent on any particular antibiotic but rather may be the result of more general antimicrobial use. If this replicon is mobile, it is to be expected that similar MDR strains of additional Salmonella serotypes will be recognized in due course.