Extraintestinal salmonellosis in a general hospital (1991 to 1996): relationships between Salmonella genomic groups and clinical presentations

An Atypical Pathogen at an Atypical Location: A Rare Case of Salmonella-Associated Submandibular Abscess

Salmonella infections commonly cause gastroenteritis and enteric fever but can also result in extraintestinal infections, especially in immunocompromised individuals. Although rare, Salmonella infection in the head and neck region was found to be more common in diabetics and patients with malignancy. We present a unique case of a 52-year-old immunocompromised man with uncontrolled diabetes who developed a submandibular abscess due to Salmonella Paratyphi B. The patient initially presented with pain, swelling, and difficulty swallowing, which worsened over a week. Diagnostic imaging revealed a well-defined abscess with lymphadenopathy. Management included incision and drainage, followed by identification of Salmonella Paratyphi B and targeted antibiotic therapy based on culture and sensitivity analysis. This case highlights the importance of early recognition, appropriate diagnostic imaging, and targeted antimicrobial therapy in managing uncommon manifestations of Salmonella infection in the head and neck. Continued vigilance and multidisciplinary management are essential for favorable patient outcomes in such cases.

Salmonella Typhi: a rare cause of parotid abscess

The incidence of extraintestinal infection caused by Salmonella spp has been increased during the past decade. Here we report a case of a parotid abscess caused by Salmonella enterica subspecies enterica serotype Typhi (S Typhi) in an individual without any significant abnormality of the parotid gland. A 68-year-old man presented to the surgical department with high-grade intermittent fever associated with painful swelling over the right side of the face, extending into the neck. An ultrasound of the neck revealed an abscess of the right parotid gland. S Typhi was isolated from the pus drained from the parotid gland. The patient was treated with intravenous followed by oral cephalosporin for a period of 7 days. This case gives an insight into one of the rarer aetiological agents causing parotid abscess.

The cellulose synthase BcsA plays a role in interactions of Salmonella typhimurium with Acanthamoeba castellanii genotype T4

Pathogenic bacteria share their natural habitat with many other organisms such as animals, plants, insects, parasites and amoeba. Interactions between these organisms influence not only the life style of the host organisms, but also modulate bacterial physiology. Adaptation can include biofilm formation, capsule formation, and production of virulence factors. Although biofilm formation is a dominant mode of bacterial life in environmental settings, its role in host-pathogen interactions is not extensively studied. In this work, we investigated the role of molecular pathways involved in rdar biofilm formation in the interaction of Salmonella typhimurium with the Acanthamoeba castellanii genotype T4. Genes coding for the rdar biofilm activator CsgD, the cellulose synthase BcsA, and curli fimbriae subunits CsgBA were deleted from the genome of S. typhimurium. Assessment of interactions of wild-type and mutant strains of S. typhimurium with A. castellanii revealed that deletion of the cellulose synthase BcsA promoted association and uptake by A. castellanii, whereas the interactions with csgD and csgBA mutants were not changed. Our findings suggest that cellulose synthase BcsA inhibits the capabilities of S. typhimurium to associate with and invade into A. castellanii.

An unusual case of Salmonella Enteritidis causing pneumonia, septic shock and multiple organ failure in an immunocompetent patient

Salmonella species are facultative intracellular pathogens that most frequently cause self-limiting gastrointestinal disease, often acquired through the ingestion of contaminated food. We report the case of a 33-year-old otherwise healthy, not overtly immunosuppressed, man who was transferred to our facility with the chief complaint of respiratory failure and septic shock. Computed tomography of the chest revealed multifocal pneumonia in both lungs. A bronchial alveolar lavage was performed in the right middle lobe and cultures predominantly grew Salmonella enterica serovar Enteritidis. The patient received a prolonged course of antimicrobials, ultimately changing to oral levofloxacin. The etiology of the salmonella infection likely occurred through an aspiration event. Salmonella species are not a typical respiratory pathogen in immunocompetent hosts; however, clinicians should be aware of the possibility that salmonella species may be a pathogenic source of infection in the lungs; a prolonged course of antimicrobials may be warranted.

Invasive Salmonellosis in Humans

Human salmonellosis is generally associated with Salmonella enterica from subspecies enterica (subspecies I). Acute infections can present in one of four ways: enteric fever, gastroenteritis, bacteremia, or extraintestinal focal infection. As with other infectious diseases, the course and outcome of the infection depend on a variety of factors, including the infecting organism, the inoculating dose, and the immune status and genetic background of the host. For serovarsTyphi and Paratyphi A there is a clear association between the genetic background of the serovar and systemic infection in humans. For serovars Paratyphi B and Paratyphi C, a good clinical description of the host and detailed population genetics of the pathogen are necessary before more detailed genetic studies of novel virulence factors,or host factors,can be initiated. For the nontyphoidalserovars (NTS) the situation is less clear. Serovars Typhimurium and Enteritidis are the most common within the food chain, and so the large number of invasive infections associated with these serovars is most likely due to exposure rather than to increased virulence of the pathogen. In Africa, however, a closely related group of strains of serovar Typhimurium, associated with HIV infection, may have become host adapted tohumans, suggesting that not all isolates called "Typhimurium" should be considered as a single group. Here we review current knowledge of the salmonellae for which invasive disease in humans is an important aspect of their population biology.

A Case Report of Acute Acalculous Cholecystitis and Acute Hemorrhagic Cystitis due to Salmonella Typhi

Acute acalculous cholecystitis and acute hemorrhagic cystitis due to Salmonella Typhi are a rare condition. A 24-year-old female patient was admitted to our clinic with abdominal pain, nausea, fever, headache, urinary burning, and bloody urine. Based on clinical, laboratory, and radiological evaluations, the patient was diagnosed with acute acalculous cholecystitis and acute hemorrhagic cystitis due to Salmonella Typhi. The patient was treated with intravenous ceftriaxone for two weeks. After the treatment, the patient's clinical and laboratory findings improved. Acute acalculous cholecystitis due to Salmonella Typhi concomitant with acute hemorrhagic cystitis is very rare and might be difficult to diagnose. Infectious agents such as Salmonella Typhi should be considered when acute acalculous cholecystitis and acute hemorrhagic cystitis are detected in adult patients with no underlying diseases.

Bilateral Breast Abscesses due to Salmonella Enterica Serotype Typhi

Focal infection is an uncommon complication of Salmonella septicemia, particularly in immunocompetent patients. The localization of Salmonella infection to breast tissue is regarded as a rare event. We report a case of bilateral breast abscesses due to Salmonellaenterica serotype Typhi in a nonlactating female and highlight the fact that Salmonella spp. should be included in differential diagnosis of abscesses in individuals coming from endemic areas with the history of recent typhoid fever and should be treated accordingly.

Clinical manifestations of nontyphoid salmonellosis in children younger than 2 years old--experiences of a tertiary hospital in southern Taiwan

BACKGROUND

Few published studies have explored the clinical manifestations of nontyphoid salmonellosis in children <2 years of age. The aim of this study was to investigate the clinical manifestations, microbiological features, complications, fecal excretion time, and responses to treatment in children <2 years of age with nontyphoid salmonellosis.

METHODS

Between January 2005 and December 2009, pediatric patients who were admitted to Kaohsiung Veterans General Hospital with positive cultures for nontyphoid Salmonella were enrolled. The following data were recorded: demographic, clinical, and microbiological features, underlying diseases, treatment regimen, complications, responses to treatment, and fecal excretion time. The clinical manifestations were compared between patients <2 years of age and patients >2 years of age.

RESULTS

Of a total 279 enrolled patients, 179 were >2 years of age. Compared with the patients who were ≥2 years of age, patients <2 years of age demonstrated a significantly higher incidence of bloody stool, mixed infection, extraintestinal infection, longer course of antibiotics, longer course of diarrhea after admission, and more days spent in the hospital. The rates of insusceptibility of nontyphoid Salmonella to ampicillin, chloramphenicol, trimethoprim/sulfamethoxazole, ceftriaxone, and ciprofloxacin in patients <2 years of age were 37.87%, 29.09%, 23.73%, 3.26%, and 2.25%, respectively. Younger patients were generally more susceptible to antibiotics than patients ≥2 years of age, although this result was not statistically significant.

CONCLUSION

The clinical manifestations of nontyphoid salmonellosis are more severe in younger children <2 years of age than older children. Local susceptibility patterns could serve as a guide for the prescription of antibiotics by clinicians.

Breast abscess in a man due to Salmonella enterica serotype Enteritidis

Nontyphoidal salmonellae can cause breast infection only exceptionally. A case of breast abscess in a 70-year-old man due to Salmonella enterica serotype Enteritidis (Salmonella Enteritidis) is reported. The infection was successfully treated with a combination of surgical and antibiotic treatment.

Cell invasion of poultry-associated Salmonella enterica serovar Enteritidis isolates is associated with pathogenicity, motility and proteins secreted by the type III secretion system

Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major cause of food-borne gastroenteritis in humans worldwide. Poultry and poultry products are considered the major vehicles of transmission to humans. Using cell invasiveness as a surrogate marker for pathogenicity, we tested the invasiveness of 53 poultry-associated isolates of S. Enteritidis in a well-differentiated intestinal epithelial cell model (Caco-2). The method allowed classification of the isolates into low (n = 7), medium (n = 18) and high (n = 30) invasiveness categories. Cell invasiveness of the isolates did not correlate with the presence of the virulence-associated gene spvB or the ability of the isolates to form biofilms. Testing of representative isolates with high and low invasiveness in a mouse model revealed that the former were more invasive in vivo and caused more and earlier mortalities, whereas the latter were significantly less invasive in vivo, causing few or no mortalities. Further characterization of representative isolates with low and high invasiveness showed that most of the isolates with low invasiveness had impaired motility and impaired secretion of either flagella-associated proteins (FlgK, FljB and FlgL) or type III secretion system (TTSS)-secreted proteins (SipA and SipD) encoded on Salmonella pathogenicity island-1. In addition, isolates with low invasiveness had impaired ability to invade and/or survive within chicken macrophages. These data suggest that not all isolates of S. Enteritidis recovered from poultry may be equally pathogenic, and that the pathogenicity of S. Enteritidis isolates is associated, in part, with both motility and secretion of TTSS effector proteins.

Molecular cloning and characterization of clyA genes in various serotypes of Salmonella enterica

Cytolysin A (ClyA) is a pore-forming hemolytic protein encoded by the clyA gene. It has been identified in Salmonella enterica serovars Typhi and Paratyphi A. To identify and characterize the clyA genes in various Salmonella enterica strains, 21 different serotypes of strains isolated from clinical specimens were presently examined. Full-length clyA genes were found in S. enterica serovar Brandenburg, Indiana, Panama, and Schwarzengrund strains by polymerase chain reaction amplification. The ClyA proteins from these four strains showed >97% amino acid identity to that of S. enterica serovar Typhi. Although all four serovars expressed detectable levels of ClyA as determined by Western blot analysis, they did not show a strong hemolytic effect on blood agar, indicating that ClyA may not be efficiently expressed or secreted. Escherichia coli transformed with clyA genes from the four serovars enhanced production of ClyA proteins and hemolytic activities to a level similar to S. enterica serovar Typhi ClyA. The present results suggest that ClyA may play a role in the pathogenesis of S. enterica serovar Brandenburg, Indiana, Panama and Schwarzengrund.

Erythema nodosum and bilateral breast abscesses due to Salmonella enterica serotype Poona

A woman presented with erythema nodosum followed by bilateral breast abscesses without a gastrointestinal manifestation, due to a rare serotype of Salmonella, namely, Salmonella enterica serotype Poona. This is the first reported case of erythema nodosum presumably associated with Salmonella infection without a gastrointestinal manifestation.

Salmonella osteomyelitis in an immunocompromized patient presenting as a primary lymphoma of the bone

During the past few decades, an increasing number of immunosuppressive drugs have been developed to treat autoimmune and rheumatic diseases, as well as post-transplant patients. In parallel, the incidence of immunocompromized patients in the general population has risen, for example, patients who are HIV positive, undergoing hemodialysis or suffering from diabetes mellitus. In such predisposed patients, infections with organisms of even reduced invasive potential can result in atypical invasive manifestations. In industrialized countries, an increase in the number of human non-typhoid Salmonella infections was observed in the 1980-1990s [Shimoni Z, Pitlik S, Leibovici L, Samra Z, Konigsberger H, Drucker M, et al. Nontyphoid Salmonella bacteremia: age-related differences in clinical presentation, bacteriology, and outcome. Clin Infect Dis 1999;28:822-7]. Beyond the main clinical manifestation of gastroenteritis, there is an increasing prevalence of extra-intestinal infections by this pathogen. We report a patient with acute osteomyelitis due to Salmonella typhimurium without any previous signs of gastroenteritis.

Non-typhoidal Salmonella septic arthritis in an immunocompetent child with a pharyngeal streptococcal infection

We report the case of an immunocompetent child who showed monoarticular arthritis and fever, preceded by pharyngitis and arthralgias. Because group A beta-hemolytic Streptococcus had been detected in the pharyngeal swab, erythromycin was given on admission. However, based on ultrasound examination, therapy with ceftriaxone and joint fluid drainage were promptly performed, and a rapid and full recovery followed. Meanwhile, Salmonella enterica infection was revealed in blood and joint fluid. Our case suggests that septic arthritis caused by a non-typhoidal Salmonella infection may occur without gastrointestinal manifestations and concomitantly with a pharyngeal streptococcal infection.

Septic arthritis of the hip with psoas abscess caused by Non-typhi Salmonella infection in an immunocompetent patient

Osteoarticular infections caused by Non-typhi Salmonella are exceptionally encountered. We report a case of a bacteriologically documented hip infection associated with a psoas abscess due to Non-typhi Salmonella. A 64-year-old immunocompetent male was admitted in our department for pain and motion range limitation in the right hip with fever. Non-typhi Salmonella was recovered in joint fluid obtained by needle aspiration. Antimicrobial chemotherapy combined with surgical intervention was necessary for eradication of the infection. Physicians should be aware of this rare manifestation of Non-typhi Salmonella infections in non-debilitated patients.

A cell-permeable fusion toxin as a tool to study the consequences of actin-ADP-ribosylation caused by the salmonella enterica virulence factor SpvB in intact cells

The virulence factor SpvB is a crucial component for the intracellular growth and infection process of Salmonella enterica. The SpvB protein mediates the ADP-ribosylation of actin in infected cells and is assumed to be delivered directly from the engulfed bacteria into the host cell cytosol. Here we used the binary Clostridium botulinum C2 toxin as a transport system for the catalytic domain of SpvB (C/SpvB) into the host cell cytosol. A recombinant fusion toxin composed of the enzymatically inactive N-terminal domain of C. botulinum C2 toxin (C2IN) and C/SpvB was cloned, expressed, and characterized in vitro and in intact cells. When added together with C2II, the C2IN-C/SpvB fusion toxin was efficiently delivered into the host cell cytosol and ADP-ribosylated actin in various cell lines. The cellular uptake of the fusion toxin requires translocation from acidic endosomes into the cytosol and is facilitated by Hsp90. The N- and C-terminal domains of SpvB are linked by 7 proline residues. To elucidate the function of this proline region, fusion toxins containing none, 5, 7, and 9 proline residues were constructed and analyzed. The existence of the proline residues was essential for the translocation of the fusion toxins into host cell cytosol and thereby determined their cytopathic efficiency. No differences concerning the mode of action of the C2IN-C/SpvB fusion toxin and the C2 toxin were obvious as both toxins induced depolymerization of actin filaments, resulting in cell rounding. The acute cellular responses following ADP-ribosylation of actin did not immediately induce cell death of J774.A1 macrophage-like cells.

Invasive non-typhoidal salmonellosis in immunocompetent infants and children

OBJECTIVE

To investigate the extraintestinal manifestations of non-typhoidal Salmonellae (NTS) infection in immunocompetent infants and children.

METHOD

The study took place at the University General Hospital at Heraklion, Crete. Over a 10-year period from 1993-2002 we studied 1087 patients, of whom 443 were children less than 14 years old, with a culture-proven diagnosis of NTS infection. Stool and blood cultures were routinely obtained in patients presenting with fever and diarrhea. The cases of invasive infection in otherwise well children, including bacteremia and/or extraintestinal focal infections were further analyzed.

RESULTS

Invasive cases were less common in children than adults (4.06% vs. 8.7%; relative risk 0.467; 95% confidence intervals (CI) 0.279-0.784; p=0.0033). Furthermore, invasive cases were much less common in the otherwise well than in immunocompromised children (3.5% vs. 21.4%; relative risk 0.163; 95% CI 0.053-0.500; p=0.0008). The 15 otherwise well children with invasive NTS infection were aged from 3 weeks to 7.5 years, and nine were aged less than 12 months. Among them, 11 presented with bacteremia, and four with focal extraintestinal infections (rectal abscess, deep neck abscess, urinary tract infection, elbow arthritis). Salmonella enterica subsp. enterica serovars Enteritidis and Virchow were the most common invasive serotypes. All invasive strains were susceptible to beta-lactams including ampicillin, and to cotrimoxazole. All patients made a complete recovery with intravenous antibiotics and did not present with relapses or major infections during long-term follow-up.

CONCLUSION

Invasive non-typhoidal salmonellosis in immunocompetent children is less frequent than in both immunocompromised children and in adulthood. However, invasive cases may well occur in otherwise healthy children, especially during infancy. In these patients, prompt appropriate treatment leads to favorable outcomes.

Nontyphoidal Salmonella causing focal infections in patients admitted at a Spanish general hospital during an 11-year period (1991–2001)

In focal infections (FI) caused by nontyphoidal Salmonella serotypes and recorded at a Spanish hospital 1991-2001, clinical and microbiological features were analyzed. Thirty-five revised episodes were related to infections of the digestive (10), urinary (10), pulmonar (4), vascular (4), osteoarticular (3) and central nervous (3) systems, and with a submaxillary lymph node. At least 16 episodes were associated with previous or concomitant gastroenteritis, 19 with primary or secondary bacteremia, and 18 with underlying diseases of different severity. Eighteen patients were male and 14 female (data were not available for three patients), while 1, 4, 12 and 15 patients were, respectively, categorized as children, young adults, senior adults and elderly. Sources of Salmonella strains were urine (13), blood (11), purulent abscess (8), cerebrospinal fluid (3), peritoneal fluid, pleural fluid, wound exudates, aneurism (2 of each), ascitic fluid, sputum, tracheal aspirate, needle aspirate, bone and lymph node (1 of each) samples. Only 28 Salmonella strains involved in FIs were available for further analysis. They were discriminated into 6 serotypes, and into 13 XbaI macrorestriction, 6 virulence, 11 antimicrobial resistance, 5 integron and 10 plasmid profiles. Broadly, the pattern of serotype distribution of salmonellas involved in FIs matched that of those causing gastroenteritis, with the pandemic Enteritidis and Typhimurium (18 and 6 strains, respectively) being clearly predominant. Within serotype, the same lineages (as revealed by XbaI-macrorestriction analysis as well as R- and V-profiles) were represented in both disease groups, with host-related factors apparently playing a more critical role than the individual strain in the outcome of the disease.

Detection of virulence determinants in clinical strains of Salmonella enterica serovar Enteritidis and mapping on macrorestriction profiles

A total of 80 strains of Salmonella enterica serovar Enteritidis, causing gastroenteritis (G) or bacteraemia (B), and three control strains (C), were subjected to: (i) detection of 14 chromosomally and 1 plasmid-located virulence genes by PCR, (ii) detection of DNA polymorphisms by XbaI and BlnI PFGE, and cluster analysis, (iii) mapping of the 15 screened sequences on macrorestriction profiles and (iv) comparison of the screening and mapping results with data available for other Salmonella strains. Identical virulence genotypes and very similar macrorestriction profiles were shown by most S. Enteritidis strains. However, a number of B strains belonged to genomic types with polymorphisms affecting fragments carrying (SPI2-slyA), (SPI2-slyA-phoP/Q-agfA), (SPI4 and/or stn) and spvC. The information obtained provides the basis for further studies on the genetic background of virulence and the molecular epidemiology of S. Enteritidis.

[Salmonellosis in a maternity-children's hospital in Barcelona over a 10-year period (1992-2001)]

BACKGROUND

We performed a retrospective study of Salmonella spp. strains, as well as of serotypes and resistance to antimicrobial agents that could be useful in salmonellosis requiring antibiotic treatment.

MATERIAL AND METHODS

All Salmonella strains isolated in a maternity-children's hospital in Barcelona (Spain) during a 10-year period (1992-2001) were serotyped. The susceptibility of the strains isolated from 1994 to ampicillin, amoxicillin-clavulanic acid, chloramphenicol, trimethoprim-sulfamethoxazole and cefotaxime was analyzed. Ciprofloxacin substituted chloramphenicol in the analysis of strains isolated during the last 2 years of the study period.

RESULTS AND DISCUSSION

A total of 860 isolates from 31 distinct serotypes were analyzed. The most frequent serotypes were S. enteritidis (48.7 %), S. typhimurium (33.4 %), S. virchow (5 %), S. hadar (1.8 %) and S. typhi (1.5 %). We found a high percentage of strains resistant to ampicillin (44.6 % in 2001) and chloramphenicol (28.7 % in 1999) and a lower percentage of strains resistant to amoxicillin-clavulanic acid and trimethoprim-sulfamethoxazole (2.2 % and 6.5 % respectively, among the strains isolated in 2001). Only one cefotaxime-resistant strain was found, and all isolates were susceptible to ciprofloxacin. Our results provide useful epidemiological information for the control of these infections, which remain a serious public health problem all over the world.

Characterization of Salmonella-induced cell death in human macrophage-like THP-1 cells

Salmonella strains are facultative intracellular pathogens that produce marked cytopathology during infection of host cells. Different forms of cytopathic effects have been associated with the virulence systems encoded by the two Salmonella pathogenicity islands (SPI-1 and SPI-2) and the spv locus. We used Salmonella enterica serovar Dublin to investigate the induction of cytopathology during infection of the human macrophage-like cell line THP-1. Analysis of host cells by flow cytometry using a fluorescent terminal deoxynucleotidyltransferase dUTP-biotin nick end labeling (TUNEL) assay revealed that 70% of THP-1 cells showed DNA fragmentation after 4 h of infection, increasing to greater than 90% by 5.5 h. Moreover, the results showed that gentamicin-killed or chloramphenicol-treated bacteria did not induce DNA fragmentation. Serovar Dublin strains with mutations in SPI-1, SPI-2, or spvB induced these cytopathic effects similar to wild-type bacteria. In contrast, a mutation in the phoP regulatory gene abolished DNA fragmentation in the TUNEL assay. Caspase-3 activation was detected during Salmonella infection of THP-1 cells, but caspase-8 and caspase-9 activities were not found. However, inhibition of caspase-3 did not block Salmonella-induced DNA fragmentation. These results identify a previously undetected apoptotic effect in Salmonella-infected cells that is dependent on phoP gene function.

A purulent pericarditis caused by Salmonella typhimurium

A case of Salmonella typhimurium pericarditis is reported. The diagnosis was based on blood and pericardial effusion cultures.

Uptake and replication of Salmonella enterica in Acanthamoeba rhysodes

The ability of salmonellae to become internalized and to survive and replicate in amoebae was evaluated by using three separate serovars of Salmonella enterica and five different isolates of axenic Acanthamoeba spp. In gentamicin protection assays, Salmonella enterica serovar Dublin was internalized more efficiently than Salmonella enterica serovar Enteritidis or Salmonella enterica serovar Typhimurium in all of the amoeba isolates tested. The bacteria appeared to be most efficiently internalized by Acanthamoeba rhysodes. Variations in bacterial growth conditions affected internalization efficiency, but this effect was not altered by inactivation of hilA, a key regulator in the expression of the invasion-associated Salmonella pathogenicity island 1. Microscopy of infected A. rhysodes revealed that S. enterica resided within vacuoles. Prolonged incubation resulted in a loss of intracellular bacteria associated with morphological changes and loss of amoebae. In part, these alterations were associated with hilA and the Salmonella virulence plasmid. The data show that Acanthamoeba spp. can differentiate between different serovars of salmonellae and that internalization is associated with cytotoxic effects mediated by defined Salmonella virulence loci.

Regional dissemination of Salmonella enterica serovar Enteritidis is season dependent

OBJECTIVE

To carry out epidemiological typing of clinical isolates of Salmonella enterica serovar Enteritidis by pulsed-field gel electrophoresis (PFGE), random amplified polymorphic DNA (RAPD) and analysis of their antibiotic resistance.

METHODS

Over a 12-month period, 44 Salmonella Enteritidis isolates, recovered from 40 patients admitted to the University Hospital Center of Amiens, France and from three outpatients, were characterized by the analysis of phenotypic and genotypic traits and clinical data from medical reports.

RESULTS

Forty nontyphoidal salmonellosis episodes were diagnosed in hospitalized patients (34 episodes of gastroenteritis, two episodes of bacteremia not affecting other organs, one episodes of bacteremia plus urinary infection, one episodes of bacteremia plus gastroenteritis, one episodes of chronic colitis plus gastroenteritis and one episode of peritonitis), and three carriers were observed in outpatients. By means of PFGE, RAPD and antibiotic susceptibility patterns 44 isolates were subdivided into 16 clonally related groups. Two of them were predominantly implicated in the course of these infections, being responsible for two successive waves of infection, while the others were encountered sporadically.

A pilot with pain in his leg: thigh abscess caused by Salmonella enterica serotype Brandenburg

Salmonella enterica serotype Brandenburg is one of the more uncommon serotypes isolated from patients with gastroenteritis. Few cases of extraintestinal infections with serotype Brandenburg have been documented. The first case of a serotype Brandenburg-dependent thigh abscess originating from an atherosclerotic pseudoaneurysm of the femoral artery is reported.

Outbreaks and sporadic cases of Salmonella serovar panama studied by DNA fingerprinting and antimicrobial resistance

In the Principality of Asturias (PA), Spain. three Salmonella serovar Panama outbreaks were registered in August 1998. In order to achieve an accurate identification of the strains implicated in the outbreaks and to study the molecular epidemiology of this serovar in the PA, the isolates collected over 1990-1999 were examined by DNA fingerprinting and antimicrobial resistance analysis. The origin of the isolates was: human (65, of which 20 were associated with the three outbreaks), octopus (2), beef (2), eggs (7), poultry faeces (2), sea water (5), sewage (2) and unknown (1). Sixteen lineages were defined by ribotyping, enterobacterial repetitive intergenic consensus sequences analysis, and randomly amplified polymorphic DNA segment analysis. One lineage was endemic in the PA and was also represented by isolates from other Spanish regions. The organisms of this lineage can be differentiated (by resistance-, plasmid- and integron-profiles) into 19 types. The three outbreaks were caused by organisms falling into a single type (nalidixic acid-resistant, plasmid- and integron-free) belonging to the endemic lineage, which was associated with poultry as the reservoir. Isolates showing drug-resistance (71%) fell into six lineages and 23 types. Ten multidrug-resistant types carried class I integrons with three types of variable regions containing resistance gene cassettes.

Actin is ADP-ribosylated by the Salmonella enterica virulence-associated protein SpvB

The Salmonella enterica virulence-associated protein SpvB was recently shown to contain a carboxy-terminal mono(ADP-ribosyl)transferase domain. We demonstrate here that the catalytic domain of SpvB as well bacterial extracts containing full-length SpvB modifies a 43 kDa protein from macrophage-like J774-A.1 and epithelial MDCK cells as shown by label transfer from [32P]-nicotinamide adenine dinucleotide (NAD) to the 43 kDa protein. When analysed by two-dimensional gel electrophoresis, the same protein was modified in cells infected with S. enterica serovariant Dublin strain SH9325, whereas infection with an isogenic spvB mutant strain did not result in modification. Immunoprecipitation and immunoblotting experiments using SH9325-infected cells identified the modified protein as actin. The isolated catalytic domain of SpvB mediated transfer of 32P from [32P]-NAD to actins from various sources in vitro, whereas isolated eukaryotic control proteins or bacterial proteins were not modified. In an in vitro actin polymerization assay, the isolated catalytic SpvB domain prevented the conversion of G actin into F actin. Microscopic examination of MDCK cells infected with SH9325 revealed morphological changes and loss of filamentous actin content, whereas cells infected with the spvB mutant remained virtually unaffected. We conclude that actin is a target for an SpvB-mediated modification, most probably ADP-ribosylation, and that the modification of G actin interferes with actin polymerization.

Severe lung lesions caused by Salmonella are prevented by inhibition of the contact system

Vascular damage induced by trauma, inflammation, or infection results in an alteration of the endothelium from a nonactivated to a procoagulant, vasoconstrictive, and proinflammatory state, and can lead to life-threatening complications. Here we report that activation of the contact system by Salmonella leads to massive infiltration of red blood cells and fibrin deposition in the lungs of infected rats. These pulmonary lesions were prevented when the infected animals were treated with H-D-Pro-Phe-Arg-chloromethylketone, an inhibitor of coagulation factor XII and plasma kallikrein, suggesting that inhibition of contact system activation could be used therapeutically in severe infectious disease.