Combining VITEK® 2 with colistin agar dilution screening assist timely reporting of colistin susceptibility.

OBJECTIVES: The rise in carbapenem resistance among Gram-negative bacteria has renewed interest in colistin. Recently, the EUCAST-CLSI Polymyxin Breakpoints Working Group declared that broth microdilution (BMD) is the only valid method for colistin susceptibility testing. BMD is not easily incorporated into the routine work of clinical laboratories, and usually this test is incorporated serially, resulting in delayed susceptibility reporting. We tested a strategy of combining VITEK® 2 with a 2 µg/mL colistin agar dilution (VITEK® 2/AD) screening plate to improve performance and time to reporting of colistin susceptibility. METHODS: Colistin susceptibility for 364 clinical isolates was determined by VITEK® 2/AD and compared with the reference standard BMD according to the ISO 20776-1:2007 and CLSI guidelines. The EUCAST colistin susceptibility breakpoint of ≤2 µg/mL was used. Escherichia coli NCTC 13846 served as quality control strain. Agreement, very major error (VME) and major error rates were determined using ISO 20776-2:2007. RESULTS: The VME rate for VITEK® 2 alone was 30.6% (15/49, 95% CI 18.3-45.4%), and was reduced to 10.2% (5/49, 95% CI 3.4-22.2%) using the VITEK® 2/AD combined testing. The combined testing had categorical agreement with BMD of 97% (354/364, 95% CI 95.0-98.7%), and a major error (ME) rate of 1.6% (5/315, 95% CI 0.5-3.7%). Using the combined testing, even against challenging strains, 349 (95.8%, 95% CI 93.3-97.7%) colistin susceptibility results could be reported, and only 15 isolates required further analysis by BMD. DISCUSSION: Our method is simple to apply and allows rapid reporting of colistin susceptibility.

The 3-day rule for stool cultures: should all patients with haematological malignancies be excluded?

OBJECTIVES: The '3-day rule' for stool culture ordering suggests that only selected inpatients with nosocomial diarrhoea should have stool cultures for enteropathogenic bacteria (EPBs). Patients with haematological malignancies are not included in this group. We have analysed the ordering of stool cultures at Laikon Hospital to investigate whether all patients with haematological malignancies should be excluded from the 3-day rule. METHODS: We have retrospectively analysed all inpatient stool specimens sent to the microbiology laboratory for enteropathogenic bacteria culture at Laikon Hospital, Athens, Greece, between January 1, 2014 and December 31, 2014. We classified stool cultures sent after the third day as 'appropriate', 'excluded' with standard rule, 'excluded' with haematological malignancies, and 'inappropriate'. RESULTS: During the study period, 1101/1593 inpatient stool cultures (69.1%) had been ordered after the third day of hospitalization. The total yield for inpatient EPB stool cultures was 0.7% (11/1593). The yield for 'appropriate' cultures was significantly higher than the yield of all 'excluded' specimens (3.7% (3/81) versus 0.3% (2/585), p 0.018) and to 'inappropriate' orders (3.7% (3/81) versus 0.0% (0/485), p 0.0028). There was no difference in the yield between specimens 'excluded' with the standard rule and 'excluded' with haematological malignancies. CONCLUSIONS: In our hospital, the yield of stool cultures from patients with haematological malignancies is similar to that of patients 'excluded' from the standard 3-day rule. If patients with haematological malignancies were not excluded from the rule, we would reduce the inpatient stool cultures by 13.6% (217/1593) at the cost of missing one positive stool culture.

Syndrome of Inappropriate Antidiuretic Hormone Secretion Complicating Systemic Nocardiosis in a Renal Transplant Recipient: A Case Report.

BACKGROUND: Infection by Nocardia species is an uncommon cause of severe clinical syndromes, particularly in immunocompromised patients, and solid-organ transplantation is the most common underlying condition. The syndrome of inappropriate antidiuretic hormone secretion (SIADH) has been described thus far in lung and stem cell transplants with systemic nocardiosis. CASE REPORT: We report the first case of SIADH in a female elderly renal transplant recipient diagnosed with systemic nocardiosis 2 years after transplantation. The SIADH was managed appropriately, and her immunosuppressive regimen remained unchanged but was adjusted at a lower level. The systemic Nocardia infection was successfully treated with intravenous administration of trimethoprim-sulfamethoxazole and imipenem for 2 weeks followed by oral trimethoprim-sulfamethoxazole for a total of 12 months. CONCLUSIONS: The SIADH syndrome is a recognizable complication of Nocardia infection in renal transplant recipients. Prompt identification along with proper management and prolonged antimicrobial treatment are essential to improve patients' outcome.

Risk factors for previously unknown meticillin-resistant Staphylococcus aureus carriage on admission to 13 surgical wards in Europe.

BACKGROUND: Early identification of meticillin-resistant Staphylococcus aureus (MRSA) carriers may be helpful for clinical and epidemiological reasons. AIM: To identify and compare risk factors of previously unknown MRSA carriage on admission to 13 surgical wards in France, Greece, Italy, and Spain. METHODS: The study was a prospective observational cohort study which enrolled consecutive patients screened for MRSA on admission to surgical wards. Sociodemographic data, comorbidities and possible risk factors for MRSA were recorded. A multivariate logistic regression model was used to predict probabilities of previously unknown MRSA colonization on admission based on patient characteristics. Prediction rules for MRSA carriage were developed and evaluated using the c-statistic. FINDINGS: Of 2901 patients enrolled, admission screening identified 111 (3.8%) new MRSA carriers. Independent risk factors for MRSA carriage were urinary catheterization (odds ratio: 4.4; 95% confidence interval: 2.0-9.9), nursing home residency (3.8; 1.9-7.7), chronic skin disease (2.9; 1.5-5.8), wounds/ulcers (2.4; 1.5-4.0), recent hospitalization (2.2; 1.5-3.3), diabetes (1.6, 1.02-2.5), and age >70 years (1.5; 1.03-2.3). However, risk factors varied between centres. The c-statistic for the common prediction rule for all centres was 0.64, indicating limited predictive power. CONCLUSIONS: Risk profiles for MRSA carriers vary between surgical wards in European countries. Identifying local risk factors is important, as a common European prediction rule was found to be of limited clinical value.

Disseminated zygomycosis with involvement of the central nervous system.

Zygomycosis of the central nervous system (CNS) can manifest in three distinct clinical forms, as rhinocerebral zygomycosis, as disseminated zygomycosis with CNS involvement, and as isolated cerebral zygomycosis. We present a case of a 2-year-old boy with leukaemia and disseminated zygomycosis, caused by Absidia corymbifera, involving the brain, spinal cord, lung and liver. The child received treatment with liposomal amphotericin B and posaconazole for 6 months. Although the lesions of the lungs and liver resolved, those of the CNS persisted and the child is in a vegetative state. A review of the literature after 2004 identified ten additional cases of disseminated zygomycosis with cerebral involvement, all but one of which had concurrent lung infection. The most common underlying disease in these cases was haematological malignancy and the mortality rate was 70%. Disseminated zygomycosis with cerebral involvement is a fatal disease. Early recognition and prompt intervention with combined medical and surgical treatment may improve the outcome.

Prevalence of macrolide resistance genes among staphylococci in Cyprus.

The aims of the present study were to evaluate the frequency of macrolide-resistant staphylococci in Cyprus and to examine the phenotypic and genotypic characteristics of these isolates. Antimicrobial susceptibility testing was performed by broth microdilution method and the macrolide resistance determinants were detected by PCR. The relatedness among the isolates was examined by pulsed-field gel electrophoresis. Ninety-six (67.61%) of the 142 Staphylococcus aureus and 19 (59.4%) of the 32 coagulase-negative staphylococci were resistant to erythromycin. Among the 115 erythromycin-resistant staphylococci, 70 expressed the MLSB-inducible phenotype, 38 the MLSB-constitutive, and 7 the MS. The predominant genes associated with macrolide resistance were the ermA for S. aureus and the ermC for coagulase-negative staphylococci, detected in 90.62% and 47.37% of the isolates respectively. Dissemination of one clone carrying the ermA gene accounted for macrolide resistance in the majority of S. aureus isolates.

Native valve Aspergillus endocarditis in two patients with aplastic anaemia.

Native valve fungal endocarditis is an uncommon disease with a high mortality rate. We present the clinical features, histological findings and outcome of 2 patients with native valve Aspergillus endocarditis. Both patients had aplastic anaemia as a predisposing disease. The diagnosis was made by Duke's criteria in 1 case and by histology in the other. Surgery was precluded owing to profound thrombocytopenia. Both patients had fatal outcome despite administration of liposomal amphotericin beta.

Long-term follow-up of children with vesicoureteral reflux with and without antibiotic prophylaxis.

The aim of the present study was to obtain data on the outcome of children with persistent vesicoureteral reflux (VUR) after cessation of antibiotic prophylaxis. Children with VUR who had been on antibiotic prophylaxis for at least 2 y and were free of urinary tract infections (UTI), had normal voiding patterns, and no hydronephrosis or new kidney scarring, had antibiotic prophylaxis discontinued, were followed up prospectively with urine cultures, voiding cystourethrography, and technecium-99m dimercaptosuccinate renal scintigraphy. The findings were compared with those of the same patients while they were on antibiotic prophylaxis. In 54 children (39 girls and 15 boys), antibiotic prophylaxis was discontinued. The mean follow-up time on and off antibiotic prophylaxis was 4.4+/-2.1 and 4.4+/-2.2 y, respectively. Nine UTI episodes occurred during the on- and 8 during the off-prophylaxis period. In 80 of 96 and in 68 of 74 ureters the reflux resolved or downgraded during the on- and off-prophylaxis periods, respectively. No new scar lesions were detected in any of the children. In conclusion, in children with persistent VUR and certain characteristics, antibiotic prophylaxis can be safely discontinued.

Brain abscesses complicating Staphylococcus aureus sepsis in a premature infant.

Brain abscess is a rare complication of staphylococcal bacteremia in infants. Here we present a case of a premature infant who developed multiple brain abscesses 12 weeks following an episode of inadequately treated Staphylococcus aureus sepsis. The abscess developed in the absence of trauma, prior surgery, cyanotic heart disease, or immune defect. The initial staphylococcal isolate exhibited identical pulsed-field gel electrophoresis pattern with that of the isolate cultured from abscess aspirate. The infant was successfully treated by surgical drainage and administration of antibiotics for 12 weeks, initially teicoplanin and meropenem followed by trimethoprim/sulfamethoxazole, without neurological or developmental sequelae. Staphylococcal bacteremia in neonates should be vigorously treated to prevent life-threatening complications.

Detection of tuberculostearic acid in serum and other biological fluids from patients with tuberculosis by electron capture-gas chromatography and chemical ionisation-mass spectrometry.

We analysed 37 clinical samples from 33 patients with bacteriologically confirmed tuberculosis, two cerebrospinal fluid samples from patients with cured tuberculous meningitis, and 14 serum samples from healthy individuals, for the presence of tuberculostearic acid (TSA) by frequency pulsed electron capture-gas chromatography (FPEC-GC) and chemical ionisation gas chromatography-mass spectrometry (CIGC-MS). TSA was detected in 36 of the 37 samples from patients with active tuberculosis and none of the patients with cured tuberculous meningitis; only one of 14 controls generated a similar chromatographic profile. Analysis of biological fluids by FPEC-GC and CIGC-MS for the presence of TSA may be a valuable method for rapid diagnosis of tuberculosis.

Electron-capture gas chromatographic-chemical ionization mass spectrometric study of sera from people vaccinated with bacille Calmette-Guerin for characteristic metabolites.

Serum samples from 26 individuals vaccinated with bacille Calmette-Guerin (BCG) and from 26 controls (10 patients with pulmonary tuberculosis and 16 non BCG-vaccinated healthy individuals) were analyzed by frequency-pulsed electron-capture gas chromatography (FPEC-GC) and chemical ionization gas chromatography-mass spectrometry (CIGC-MS) for the presence of characteristic metabolites. A distinct pattern consisted of tuberculostearic acid (TSA) and a peak, labeled peak 1, was observed in all BCG-vaccinated individuals, whereas only three of 26 controls generated this chromatography profile. TSA was detected in all patients with pulmonary tuberculosis but peak 1 was absent. Sera drawn from 12 individuals 11 to 14 days after BCG vaccination yielded three transitional FPEC-GC profiles. A permanent FPEC-GC profile consisting of TSA and of a full scale peak 1 appeared 28 days to a few months after BCG vaccination. Peak 1 was tentatively identified by CIGC-MS as 9-methyl-hexacosanol. The findings suggest that peak 1 may serve as a marker to detect Mycobacterium bovis BCG and to distinguish individuals infected with M. tuberculosis from individuals vaccinated with BCG.

Disseminated miliary tuberculosis of the skin in patients with AIDS: report of four cases.

We present clinical, bacteriologic, and pathological findings for four patients with AIDS and cutaneous miliary tuberculosis. All patients had generalized tuberculosis with hematogenous dissemination to multiple organs including the skin. Microscopic examination of the skin lesions revealed ill-formed or no granulomata, extensive necrosis, and numerous acid-fast bacilli. Mycobacterium tuberculosis was detected in the skin lesions by cultures for three patients and by polymerase chain reaction for one. Three of the isolates were resistant to at least isoniazid and rifampin, and one was susceptible to these drugs. The outcome was rapidly fatal for the three patients with multidrug-resistant tuberculosis. This report draws attention to the reappearance of a once-rare manifestation of disseminated tuberculosis which, in the setting of advanced human immunodeficiency virus disease, may offer the first indication of infection with multidrug-resistant M. tuberculosis and a poor prognosis.

An evaluation of oral ulcers in patients with AIDS and AIDS-related complex.

BACKGROUND: Patients with HIV infection can have recurrent and persistent oral ulcers, not attributable to known infectious agents. OBJECTIVE: Our aim was to evaluate prospectively oral ulcers in patients with HIV infection to determine whether an etiologic agent could be identified. METHODS: Sixteen patients with HIV infection who had oral ulcers not attributable to known causes had culture of the base and a biopsy specimen taken from the ulcer. Cultures were obtained for herpes simplex and varicella-zoster viruses, mycobacteria, and fungi. By polymerase chain reaction (PCR) analysis with primer/probe sets for herpes simplex viruses 1 and 2, varicella-zoster virus, cytomegalovirus, human papillomavirus, and Mycobacterium tuberculosis, each biopsy specimen was analyzed for the presence of DNA from these organisms. Specimens were also evaluated histologically. RESULTS: Histoplasmosis was detected histologically in one biopsy specimen, candidiasis in a second, and herpetic changes in a third. Viral cultures were positive for herpes simplex virus 1 in four cases and herpes simplex virus 2 in one case. PCR analysis detected DNA for herpes simplex virus 1 in one case and herpes simplex virus 2 in another; DNA from other pathogens was not identified. In the remaining eight patients, hematoxylin-and-eosin staining revealed eosinophilic ulcers in five cases and nonspecific changes in three cases. CONCLUSION: The etiologic agent of recurrent or persistent oral ulcers in patients with AIDS and AIDS-related complex was not identified in 50% of patients. PCR analysis was not useful. Herpes simplex virus or other pathogens were not detected in ulcers containing numerous eosinophils.

Clinical presentation and outcome of patients with HIV infection and tuberculosis caused by multiple-drug-resistant bacilli.

OBJECTIVE: To determine the clinical manifestations of patients with human immunodeficiency virus (HIV) infection and tuberculosis caused by multiple-drug-resistant bacilli compared with those with single-drug-resistant or susceptible bacilli. DESIGN: Descriptive, case-control, and cohort studies. SETTING: A large urban teaching hospital. PATIENTS: Sixty-two patients with tuberculosis caused by multiple-drug-resistant bacilli (cases) and 55 patients with tuberculosis caused by single-drug-resistant or susceptible bacilli (controls). MEASUREMENTS: Characteristics of clinical presentation, radiographs, pathologic abnormalities, antituberculosis treatment, and clinical course. RESULTS: Twenty cases (32%) had concomitant pulmonary and extrapulmonary disease at presentation compared with 9 controls (16%; odds ratio, 2.4; 95% CI, 1.0 to 5.9). More cases had alveolar infiltrates (76%; odds ratio, 3.6; CI, 1.2 to 11.4), interstitial infiltrates with a reticular pattern (67%; odds ratio, 7.8; CI, 1.0 to 83.5), and cavitations (18%; odds ratio, 6.6; CI, 0.8 to 315.3) on initial chest radiographs compared with controls (49%, 19%, and 3%, respectively). Pathologic specimens from cases showed extensive necrosis, poor granuloma formation, marked inflammatory changes with a predominance of neutrophils, and abundant acid-fast bacilli. Twenty-five cases received two or more effective antituberculosis drugs for more than 2 months. Only 2 cases had three consecutive negative cultures for Mycobacterium tuberculosis; one patient died within 1 day of the last negative culture, and the other had positive cultures 496 days later. The remaining 23 cases had persistently or intermittently positive cultures despite therapy. The clinical course of these cases suggested overwhelming miliary tuberculosis with involvement of the lungs (77%), pleura (15%), stool (34%), meninges (13%), bone marrow (16%), blood (10%), lymph nodes (10%), and skin (8%). The median survival time was 2.1 months for cases compared with 14.6 months for controls (P = 0.001, log-rank test). CONCLUSIONS: Tuberculosis caused by multiple-drug-resistant bacilli in patients with HIV infection is associated with widely disseminated disease, poor treatment response with an inability to eradicate the organism, and substantial mortality.