Rapid identification and antimicrobial susceptibility testing of Gram-negative rod on positive blood cultures using MicroScan panels

Shortening the turnaround time of antimicrobial susceptibility testing (AST) of bacteria permits a significant reduction of patient morbidity, mortality, and cost. Conventional blood culture methods are the gold standard diagnostic test to guide management of patient with sepsis, but the conventional process requires at least 12 to 24 h after the blood culture has been flagged as positive due to requirement for pure colonies. We describe a simple and inexpensive method to obtain faster AST with MicroScan system (Beckman Coulter) directly from positive blood cultures. Conventional and direct identification and AST were performed simultaneously by both methods in 1070 blood cultures, and 9106 MICs were determinated. About 96.5% were correctly identified with the direct method. Overall, categorical agreement was 92.86%. We found 46 very major errors, but globally the results showed a good correlation with the standard method, particularly favorable for E. coli and K. pneumoniae, except amoxicillin-clavulanate and piperacillin-tazobactam. For P. mirabilis, betalactams antibiotics (except second- and third-generation cephalosporines) showed a good correlation, and also a good correlation was found for ciprofloxacine and gentamicine in P. aeruginosa and amoxicillin-clavulanate, ciprofloxacine, gentamicine, and cotrimoxazole in E. cloacae. This method has the main advantage of providing reliable results 1 day earlier, being a simple, fast, and cheap method for identification and antimicrobial susceptibility testing results from positive blood cultures.

[Thoracic actinomycosis: an old disorder with new clinical manifestations]

Three cases of thoracic actinomycosis are described, two associated to bronchial obstruction (foreign body and bronchogenic carcinoma) and one in a patient with empyema. The clinical and radiological manifestations and diagnostic criteria are reviewed and all published cases in the Spanish literature are thoroughly analyzed.

Cutaneous hyalohyphomycosis caused by Paecilomyces lilacinus in an immunocompetent host successfully treated with itraconazole: case report and review

Paecilomyces lilacinus is an emerging fungal pathogen that is highly resistant to many antifungal drugs. Skin and subcutaneous soft tissue infections caused by this organism are very unusual. Most cases occur in patients with impaired host defenses or following surgical procedures. There has been only one previous report of a histologically confirmed cutaneous infection due to Paecilomyces lilacinus in a patient without predisposing factors. Described here is the second histopathologically proven case of Paecilomyces lilacinus cutaneous infection in a healthy patient without any apparent portal of entry. Prolonged antifungal chemotherapy with itraconazole led to resolution of the skin lesion. This case of sporadic cutaneous infection due to Paecilomyces lilacinus is believed to be the first reported in Europe and the first histopathologically proven case successfully treated with itraconazole.

Corynebacterium pseudodiphtheriticum pneumonia in an immunocompetent patient

Corynebacterium pseudodiphtheriticum is a coryneform and diphtheromorphic bacteria rarely found as a cause of pneumonia in immunocompetent hosts. A case of an immunocompetent patient with C. pseudodiphtheriticum pneumonia is presented. This infection responded well to initial empirical treatment with cefotaxime. Very few cases of pneumonia associated with C. pseudodiphtheriticum have been described in the medical literature, this organism mainly being found in immunocompromised hosts. We report a case of pneumonia in an immunocompetent patient in which C. pseudodiphtheriticum was the only micro-organism isolated.

Corynebacterium pseudodiphtheriticum: an easily missed respiratory pathogen in HIV-infected patients

Despite being a well-known respiratory pathogen for immunocompromised patients, Corynebacterium pseudodiphtheriticum has uncommonly been reported to occur in persons with infection attributable to HIV virus. We report three cases of respiratory tract infection attributable to C. pseudodiphtheriticum in HIV-infected patients and review the four previous cases from the medical literature. All of them were male with a median CD4 lymphocyte count of 110 cells/mm3 (range, 18-198/mm3); five of the seven cases occurred in persons for whom AIDS was diagnosed previously. The onset of symptomatology was usually acute and the most common radiographic appearance was alveolar infiltrate (six patients) with cavitation (two patients) and pleural effusion (two patients). In five of the seven cases, C. pseudodiphtheriticum was isolated from bronchoscopic samples and in the remaining two cases was recovered from lung biopsy (one patient) and sputum (one patient). In the three patients reported herein and in one previous case from the medical literature, quantitative culturing of bronchoscopic samples obtained through either bronchoalveolar lavage or protected brush catheter procedures yielded more than 10(3) CFU/mL. All the strains tested were susceptible to penicillin and vancomycin. Resistance to macrolides was common. Recovery was observed in six of the seven patients. C. pseudodiphtheriticum should be regarded as a potential respiratory pathogen in HIV-infected patients. This infection presents late in the course of HIV disease and it seems to respond well to appropriate antibiotic treatment in most of the cases. This easily overlooked pathogen should be added to the list of organisms implicated in respiratory tract infections in this population.

Endocarditis caused by Stenotrophomonas maltophilia: case report and review

Stenotrophomonas (Xanthomonas) maltophilia is a rare cause of endocarditis. The extensive resistance of this organism to several antibiotics leaves few options for antimicrobial therapy. In vitro synergism of the combination of trimethoprim-sulfamethoxazole (TMP-SMZ) and ticarcillin/clavulanic acid (TIC/CA) has been demonstrated. To our knowledge, we report the first case of ventriculoatrial cerebrospinal fluid shunt-associated endocarditis due to S. maltophilia. The patient was cured with combination therapy with TMP-SMZ and TIC/CA along with catheter removal. This is also the first report of S. maltophilia endocarditis successfully treated with this antibiotic combination. In a review of the medical literature, only 16 cases of S. maltophilia endocarditis were found. Most patients were intravenous drug users (43.8%) or had either prosthetic heart valves (50%) or an indwelling vascular catheter (18.8%). Although S. maltophilia is usually considered a nosocomial pathogen, about one-half of the cases were community-acquired. Twelve of sixteen patients had left-sided endocarditis. Therapy with a combination of two or more antibiotics was employed in most cases. Seven patients had been given TMP-SMZ therapy, but none had been treated with TIC/CA before. One-half of the patients required cardiac surgery. The overall mortality rate was 33%. Although the optimal antibiotic treatment for S. maltophilia endocarditis remains unknown, the case reported herein reinforces in vitro findings that the combination of TMP-SMZ and TIC/CA may be effective therapy.

Staphylococcus lugdunensis as a cause of abscesses in the perineal area

The first two patients with skin infections in the perineal area due to Staphylococcus lugdunensis are described. One had an abscess of the Bartholin gland, and the other presented with several cutaneous abscesses in the pubic area, which had a prolonged and recurrent clinical course despite appropriate antibiotic treatment. This report emphasizes the pathogenic role of Staphylococcus lugdunensis and the importance of identifying coagulase-negative staphylococci to species level in some instances.

[Spontaneous bacterial peritonitis due to Listeria monocytogenes]

We present a case of spontaneous bacterial peritonitis (SBP) caused by Listeria monocytogenes in a patient previously diagnosed as alcoholic liver cirrhosis. The clinical presentation, biochemical data and outcome of the patient are compared with those of cases of SBP caused by Listeria monocytogenes in patients with cirrhosis published in the Spanish and English literature. Twelve out of 20 cases described in the literature were published by Spanish authors. This greater proportion could be related to dietary habits (greater consumption of fruits and vegetables), climatic or demographic factors. We underline the importance of pursuing a microbiological diagnosis since Listeria monocytogenes is intrinsically resistant to cefotaxime, the antimicrobial often selected to empirically treat SBP episodes.

Risk factors for acquisition of urinary tract infections caused by ciprofloxacin resistant Escherichia coli

From January 1990 to December 1992, ciprofloxacin resistant Escherichia coli was isolated in 125 of 1,946 urine cultures (6.4%) with more than 10(5) colony-forming units per ml. To determine the risk factors for acquisition of urinary tract infections caused by ciprofloxacin resistant E. coli a retrospective chart review was done. Data from 54 patients with urinary tract infections caused by ciprofloxacin resistant E. coli were compared with 51 controls matched by temporal occurrence and randomly selected among 540 patients with urinary tract infections caused by ciprofloxacin susceptible E. coli. Patients had greater proportions of asymptomatic bacteriuria or lower urinary tract symptoms (85% versus 61%, p = 0.01) and of relapse (22% versus 0%, p = 0.001) than controls. Urinary tract abnormalities (odds ratio 7.98, 95% confidence interval 2.7 to 3.1, p < 0.001), patient age 65 years or older (odds ratio 6.48, 95% confidence interval 2.2 to 19.1, p < 0.001), previous treatment with quinolones (odds ratio 19.09, 95% confidence interval 2.2 to 166.5, p = 0.008) and urinary catheterization (odds ratio 2.92, 95% confidence interval 1.1 to 8.5, p = 0.048) were independently associated with infections caused by ciprofloxacin resistant strains. Our results suggest that patients with urological abnormalities previously treated with quinolones are especially prone to urinary tract infection caused by ciprofloxacin resistant strains.

Review of pulmonary brucellosis: a case report on brucellar pulmonary empyema

In certain geographic areas, among which most South European countries are included, brucellosis continues to be an important health problem. Despite the disease's continued high prevalence, the advances made in its diagnosis and treatment have contributed to the rarity of different focal locations, such as the lung. Formerly, these occurrences were much more frequent. The present work offers a review of the literature on pulmonary brucellar affection and describes a case report of brucellar pulmonary empyema with isolation of Brucella melitensis from the pleural exudate. This constitutes an exceptional circumstance even in areas considered hyperendemic, such as a large part of Spain.