Erratum to: Antimicrobials: a global alliance for optimizing their rational use in intra-abdominal infections (AGORA).

[This corrects the article DOI: 10.1186/s13017-016-0089-y.].

A pseudoepidemic due to laboratory contamination deciphered by molecular analysis.

OBJECTIVE: A clinical, microbiological, and molecular analysis to identify the source of a cluster of pseudoinfections. DESIGNS: Retrospective analysis of the cases, prospective epidemiologic survey, and laboratory investigation. Molecular analysis of the isolates was performed using pulsed-field gel electrophoresis (PFGE). SETTING: A tertiary Veterans Affairs medical center. PATIENTS: Three patients admitted over a 2-week period with musculoskeletal complaints had one or more joint fluid specimens submitted for culture. In each case, anaerobic chopped meat-glucose broth (CMGB) tubes yielded one or more organisms not typically associated with septic arthritis (Enterobacter cloacae, Enterococcus faecium, Enterococcus casseliflavus, Enterococcus faecalis, Escherichia hermannii, and Pseudomonas diminuti). The first three organisms were isolated from specimens from multiple patients. Two patients had multiple positive cultures; for two patients, separate cultures yielded additional organisms on solid media. RESULTS: Laboratory investigation yielded an isolate of E faecium from 1 of 30 sham-inoculated CMGB tubes. PFGE analysis demonstrated that a single strain of E cloacae was isolated from four CMGB tubes representing all three patients, and a single strain of E faecium was isolated from CMGB tubes representing two patients and the sham-inoculated tube. CONCLUSIONS: The application of molecular typing clearly demonstrated clonality among the isolates and indicated that a common source of contamination, most likely the CMGB tubes, was responsible for these cases.

Nosocomial septicemia with CDC group IV c-2, an unusual gram-negative Bacillus.

A 55-year-old man with severe peripheral vascular disease developed nosocomial septicemia which was caused by the gram-negative bacterium CDC group IV c-2, presumably from a plantar abscess on the left foot. Recovery followed amputation of the infected extremity and antibiotic therapy. This is the first reported case of nosocomial acquisition of this organism.

Relationship between host age and susceptibility to oral colonization by Actinomyces viscosus in Sprague-Dawley rats.

The colonization of Actinomyces viscosus strain Ny-1R on the molar teeth of conventional and ex-germfree rats of various ages fed either a high-sucrose diet, a high-glucose diet, or laboratory chow was studied. Conventional rats directly after weaning and up to 30 days of age are less susceptible to experimental infection by strain Ny-1R than are older rats regardless of the test diet. The relationship between host age and susceptibility to infection is also demonstrable in ex-germfree rats fed a high-sucose diet. Host factors responsible for the differences in susceptibility were investigated. The results from these studies do not implicate host antibodies, host indigenous flora, or host saliva. In other studies, it was demonstrated that within the mouths of rats, strain Ny-1R preferentially colonizes in the pits and fissures of the molar teeth rather than on the dorsum of the tongue or on the vestibular mucosa. In short-term experiments, it was found that strain Ny-1R attaches to the first molars of 40-day-old conventional rats to a greater extent than it attaches to the first molars of 20-day-old rats. The differences in attachment and subsequent colonization of strain Ny-1R in 20- and 40-day-old rats may be related to the varying amounts of the reduced enamel epithelium and connective tissue present in the fissures of the molar teeth.

Role of colonization in the virulence of Actinomyces viscosus strains T14-Vi and T14-Av.

Germfree rats fed a high-sucrose diet were inoculated with Actinomyces viscosus strain T14-Vi (virulent) or T14-Av (avirulent). The mean recovery of strain T14-Vi from six extracted finely ground molars of rats sacrificed after 90 days was 1.1 x 10(8) colony-forming units (CFU). The mean recovery of strain T14-Av was 5.7 x 10(7) CFU, which was significantly less. Strain T14-Vi caused severe alveolar bone loss, but only minimal bone loss occurred in rats infected with strain T14-Av. Scanning electron microscopy of teeth of germfree rats revealed that strain T14-Vi colonized in the fissures as well as on tooth surface areas near the gingiva; strain T14-Av also colonized in fissures but was unable to colonize the teeth near the gingiva. In studies with conventional rats fed a high-sucrose diet, streptomycin-resistant strain T14-Vi colonized on the teeth of all rats inoculated with in the order of 10(8) or 10(7) CFU and on the teeth of about half of the rats inoculated with 10(6) or 10(5) CFU. In contrast, streptomycin-resistant strain T14-Av could not be detected on the teeth of any of the rats in groups similarly inoculated. In vitro "resting" cells of both strains suspended in conventional or germfree rat saliva survived to comparable degrees. [(3)H]thymidine-labeled T14-Vi cells adhered well to hydroxyapatite (HA) beads and to HA beads pretreated with saliva obtained from germfree or conventional rats. In contrast, T14-Av cells adhered less well than did T14-Vi cells to HA, whereas their adherence to saliva-coated HA was negligible. Transmission electron microscopy of negatively stained T14-Vi and T14-Av cells repeatedly passed in 1% phosphotungstic acid revealed fibrils on cells of both strains. T14-Av cells were covered by large amounts of extracellular material which was presumably heteropolysaccharide; little extracellular material was present on the surface of T14-Vi cells. T14-Vi cells had a relatively low affinity for the heteropolysaccharide synthesized by strain T14-Av. Other evidence also suggested that this polysaccharide had a relatively low affinity for saliva-coated HA. Collectively, the evidence indicates that the difference in periodontopathic potential between strains T14-Vi and T14-Av results from their different abilities to colonize teeth. This difference is probably due to the lower adherence of T14-Av cells to teeth rather than to their ability to grow in the mouth. The low affinity of T14-Av cells for tooth surfaces may be due, in part, to the presence of large amounts of cell-surface-associated polysaccharide.

Polymicrobial bacterial pericarditis after transbronchial needle aspiration. Case report with an investigation on the risk of bacterial contamination during fiberoptic bronchoscopy.

A 63-yr-old man developed pericardial effusion with tamponade after transbronchial needle aspiration (TBNA) of a subcarinal mass. A diagnosis of polymicrobial bacterial pericarditis was made when pericardiocentesis revealed purulent fluid that grew a mixed culture of anaerobes and aerobes, organisms that constitute part of the normal upper respiratory tract flora. To examine the possibility that contamination of the transbronchial needle (TBN) could lead to purulent pericarditis by inoculation of bacteria into the mediastinum, quantitative cultures of the TBN content were performed in seven consecutive patients. Abundant growth of multiple anaerobic and aerobic organisms was demonstrated in all seven cultures. We conclude that subcarinal TBNA is another potential cause of purulent pericarditis. This results from upper respiratory tract contamination of the open distal end of the TBN as it passes through the suction channel of the bronchoscope.

Sensitivity and specificity of an improved rapid latex agglutination test for identification of methicillin-sensitive and -resistant Staphylococcus aureus isolates.

The performance of a second-generation rapid agglutination kit, Slidex Staph Plus (SSP; bioMérieux), was compared to those of the Slidex Staph (SS; bioMérieux), Staphaurex (SRX; Murex Diagnostics), and BBL Staphyloslide (BBL; Becton Dickinson) kits by using 508 clinical isolates composed of 150 methicillin-sensitive Staphylococcus aureus (MSSA) organisms, 154 methicillin-resistant S. aureus (MRSA) organisms, and 204 non-S. aureus Staphylococcus spp. Of the 508 isolates tested, 75% were fresh clinical isolates, with the remainder taken from five different freezer collections. All four agglutination tests had comparable sensitivities for MSSA and MRSA. However, the SS kit was significantly less specific (93.1%) than the three other tests (P > 0.05, McNemar test). These results demonstrate that the new rapid latex agglutination kit, SSP, was more specific for the identification of S. aureus than the previous version and performed comparably to the SRX and BBL kits.

Relationship between indole production and differentiation of Klebsiella species: indole-positive and -negative isolates of Klebsiella determined to be clonal.

Klebsiellae are an important cause of nosocomial infections. The two clinically relevant species, Klebsiella pneumoniae and Klebsiella oxytoca, are differentiated by the ability to produce indole from tryptophan, K. oxytoca being indole positive. We report here the detailed biochemical and molecular analysis of two isolates of Klebsiella, cultured from the same urine specimen, that differed only in their ability to produce indole. The two isolates were identical as determined by ribotyping and pulsed-field gel electrophoresis, and they differed from 10 epidemiologically unrelated strains. Probing with the Escherichia coli tryptophanase operon, tna, revealed seven restriction fragment length polymorphisms (RFLP) among the 12 strains. The two index strains had identical RFLP; no single RFLP could account for all of the indole-positive or -negative strains. Thus, the identification of epidemiologically related strains of Klebsiella differing only in indole production may warrant further examination to determine whether the strains are clonal.

Molecular confirmation of bacillus Calmette-Guérin as the cause of pulmonary infection following urinary tract instillation.

Instillation into the urinary tract of the bacillus Calmette-Guérin (BCG), a strain of Mycobacterium bovis, is associated only rarely with severe side effects. We report here two cases of culture-proven pulmonary infection due to therapy with BCG. The first patient, who was seropositive for the human immunodeficiency virus, developed bilateral interstitial pneumonitis after instillation of BCG into the bladder. The second patient developed a right-lower-lobe infiltrate and empyema after instillation of BCG into the right renal pelvis. The clinical isolates from these two patients and from a third patient with a psoas abscess following intravesical instillation were analyzed with use of pulsed field gel electrophoresis (PFGE) to resolve chromosomal restriction fragment polymorphisms. The clinical isolates were confirmed to be BCG by comparison with known vaccine strains that differed from M. bovis isolates. We conclude that the potential for subsequent dissemination be considered prior to the intravesical administration of BCG. Analysis with PFGE may be useful for identifying species of the Mycobacterium tuberculosis complex.

Biodistribution and genetic stability of the novel antitumor agent VNP20009, a genetically modified strain of Salmonella typhimurium.

VNP20009 is a genetically modified strain of Salmonella typhimurium possessing an excellent safety profile, including genetically stable attenuated virulence (a deletion in the purI gene), reduction of septic shock potential (a deletion in the msbB gene), and antibiotic susceptibility. VNP20009 is genetically stable after multiple generations in vitro and in vivo. In mice, VNP20009 is rapidly cleared from the blood from a peak level of 1x104 cfu/mL to undetectable levels in 24 h. In tumor-bearing mice, VNP20009 accumulates preferentially in tumors over livers at a ratio of 1000&rcolon;1. In nonhuman primates, VNP20009 was also rapidly cleared from the blood, from a peak level of 1.0x106 cfu/mL to undetectable levels in 24 h. VNP20009 was detected in the liver, spleen, and bone marrow of monkeys; the amount decreased over time, and VNP20009 was cleared from all organs by day 41; no VNP20009 could be detected in the urine or feces of the monkeys. VNP20009 is genetically stable after many generations of growth (>140) both in vitro and in vivo.