Clostridium difficile. A review on an emerging infection.

Clostridium difficile causes antibiotic-associated diarrhoea and pseudomembranous colitis. The main virulence factors of C. difficile are the toxins A (TcdA) and B (TcdB). A third toxin, binary toxin (CDT), which pathogenetic role had been remained largely overlooked until few years ago, nowadays have been detected in 5%-23% of strains. C. difficile has spread around world. Clostridium difficile infection (CDI) is one of the most common health-care associated infections and a significant cause of morbidity and mortality among older adult hospitalized patients. Diagnosis of CDI is often difficult and has a substantial impact on the management of patients with disease. It is usually based on a clinical history of recent antimicrobial usage and diarrhoea in combination with laboratory tests. Although the conventional methods are crucial for the diagnosis and the subsequent treatment of CDI, a timely laboratory diagnosis is essential for the detection of toxigenic strains providing either to an effective and immediately treatment or to the prevention of further disease transmission. In this review we provide general recommendations for testing of samples collected from patients with suspected CDI.

Monoclonal gammopathy of undetermined significance in pediatric kidney transplant: a possible role of Epstein-Barr virus.

MG is a common event of hematologic malignancies. There are many papers regarding kidney transplantation patients with MGUS in adults, while data in pediatrics are scarce. The etiology and clinical significance of MGUS are unclear both in adults and children. Immunosuppressive drugs, graft antigenicity, and viral infection could play a possible role. The viruses most frequently implicated seem to be EBV or CMV in particular, but their role has to be defined better. However, many investigators have emphasized an impaired balance between an adequate immune response and reactivation of viral infection.

Evaluation of a rapid test for the diagnosis of pneumococcal pneumonia.

We evaluated the usefulness of a rapid immunochromatographic pneumococcal urinary antigen test (UAT) for the diagnosis of pneumonia over a period of five years. The UAT was positive in 32 (2.3%) urine samples obtained from 1414 patients. In 46 of these 1414 patients results of UAT and/or sputum/pleural fluid culture and/or blood culture and/or procalcitonin levels were available and therefore the study was concentrated on these patients. A concordance between UAT positivity and the presence of Streptococcus pneumoniae in the sputum was observed in only 4 of 46 (8.7%) patients for which both urine and sputum samples were analyzed. A discordant result (UAT positive and absence of S. pneumoniae in sputum samples) was recorded in 8 of 46 (17.4 %) patients. UAT negative results with sputum culture positive for S. pneumoniae were recorded in 28.3% of patients. In 20 patients, UAT tested positive but sputum culture was not performed. A concordance between UAT positivity and the isolation of S. pneumoniae from blood was seen in 2 of 46 patients whereas a discordant result (UAT positive and blood culture negative) was seen in 12 (26.1%) patients. A concordance between the UAT and high levels (≥2ng/ml) of procalcitonin was observed in 4 out of 46 patients, whereas a positive UAT result and a procalcitonin negative result were observed in 2 patients. In our experience the UAT allows the detection of the etiological agent of pneumonia, and also when sputum and/or blood cultures are negative for S. pneumoniae, when the clinical picture is suggestive of alveolar pneumonia.

Antimicrobial resistance among uropathogens responsible for community-acquired urinary tract infections in an Italian community.

This study aimed to establish the pattern of the antimicrobial resistance among the leading uropathogens causing community-acquired UTIs in an area of the region of Apulia, Southern Italy. Twenty-one thousand and two hundred outpatients, 6,893 males and 14,307 females, were enrolled. Urinary isolates were identified by conventional methods and the susceptibility to 18 antimicrobials determined. Recognized uropathogens Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis were isolated from 3175 positive samples, E. coli accounting for 68.04% of positive cultures. Most overall resistance was to ampicillin, while the resistance rate to cephalothin was higher than that of third generation cephalosporins. Although to a different degree, all the bacteria had an overall good susceptibility rate to quinolones as well as to fosfomycin but increased resistance to sulfamethoxazole/trimethoprim. Our results confirm that E. coli is the leading uropathogen and provide information about the antimicrobial susceptibility patterns of the main pathogens causing community-acquired UTIs. These findings should be taken into account to help maintain the safety and efficacy of treatment for community-acquired UTIs.

In vitro antimicrobial activity of benzalkonium chloride against clinical isolates of Streptococcus agalactiae.

OBJECTIVES: Despite antibiotic prophylaxis for at-risk mothers during labour and delivery, Streptococcus agalactiae (group B Streptococcus; GBS) still causes substantial morbidity and mortality among newborns. In addition to the well-known side effects of the administration of antibiotics, resistance to drugs recommended for penicillin-allergic pregnant women, such as erythromycin and clindamycin, has increased, thus raising concern about the possibility of inadequate prophylaxis. On this basis we evaluated the antimicrobial activity of benzalkonium chloride against GBS, which has been described as an antimicrobial agent for the topical treatment of vaginal infections. METHODS: A total of 52 GBS from pregnant women have been studied. The capacity of benzalkonium chloride as well as of penicillin, erythromycin, clindamycin, vancomycin, chloramphenicol and tetracycline to inhibit GBS was evaluated using broth macrodilution and microdilution methods, respectively. RESULTS: While all the strains were penicillin- and vancomycin-susceptible, 19.2% were resistant to both erythromycin and clindamycin. In contrast, all GBS isolates were either inhibited or killed by benzalkonium chloride at not only low but also very similar concentrations (MIC90 = 3.12 mg/L). CONCLUSIONS: Benzalkonium chloride might represent an alternative strategy that is useful in reducing vaginal GBS colonization in pregnant women before delivery by topical treatment.

Serological study on Chlamydophila pneumoniae in patients with community-acquired pneumonia.

This study aimed to evaluate the incidence of Chlamydophila pneumoniae antibodies in patients with community acquired pneumonia (CAP) by a new ELISA test (EIA CP-IgG, IgA, IgM--Eurospital, Trieste, Italy). From January 1999 to July 2001 141 patients with clinical signs of CAP were enrolled in sixteen Italian Hospitals. Specific IgM and IgG antibodies anti-C. pneumoniae in serum and IgA in both serum and sputum were detected. At a primary inspection (time T-0) serum and sputum samples were taken from 115/141 patients, whereas serum was collected from only 100/141 patients after 30 days (time T-30). At T-0 24/115 (20.8%) patients showed serological markers thus suggesting an acute C. pneumoniae infection. In 23/24 patients the overall serological pattern found at T-0 was confirmed at T-30. In 32/115 patients (27.8%) serological markers of C. pneumoniae past infection were found positive and were confirmed 30 days later. These data support the role of C. pneumoniae as an important aetiological agent of CAP throughout different geographic areas of Italy. The test was suitable for the laboratory diagnosis of C. pneumoniae infection. In particular, the presence of specific IgA anti- C. pneumoniae in both serum and sputum proved useful to define different stages and evolution of infection.

[Nasopharyngeal colonization of Streptococcus pneumoniae in healthy children: percentage of carriers, serotypes distribution and antibiotic resistance]. / Colonizzazione nasofaringea di Streptococcus pneumoniae in bambini sani: percentuale di portatori, distribuzione dei sierotipi e antibiotico-resistenza.

AIM: The nasopharyngeal carriage of Streptococcus pneumoniae is an important risk factor for pneumococcal diseases. Data regarding prevalence and serotype distribution of this pathogen are lacking in our population. EXPERIMENTAL DESIGN: longitudinal observational cohort study. SETTING: healthy children aged 1-7 years attending day-care centers and schools of a district of a Southern Italy city. MEASURES: the nasopharyngeal colonization rate of Streptococcus pneumoniae as well as its antibiotic susceptibility was determined. RESULTS: Of 317 nasopharyngeal cultures obtained, 18.29% of the cultures were positive for Streptococcus pneumoniae; 60.34% of the isolates were serotypes 19A, 19F, 14, 6B, or 23F; 8.62% of the strains were intermediately resistant to penicillin. Erythromycin-resistance was observed in 65.51% of the micro-organisms isolated and particularly serotypes 19, 14, and 6 were more erythromycin-resistant than organisms of other serotypes. Co-trimoxazole resistance was detected in 17.24% of the strains. All the strains resulted uniformly susceptible to cefotaxime and ceftriaxone. CONCLUSION: The high rate of nasopharyngeal carriage of Streptococcus pneumoniae, along with the resistance to antibiotics widely used in the community, suggests the importance of an epidemiological surveillance as well as the application of new vaccine strategies.

Streptococcus pneumoniae nasopharyngeal colonization in young healthy children: rate of carriage, serotype distribution, and antibiotic resistance.

The nasopharyngeal colonization rate of Streptococcus pneumoniae and its antibiotic susceptibility was determined in a given population of 317 young children (ages 1-7 years) in the area of Bari, Italy. 18.29% of the cultures were positive for S. pneumoniae. 8.62% of the strains were intermediately resistant to penicillin. Erythromycin-(65.51%) and cotrimoxazole-(17.24%) resistance was also observed whereas all the strains resulted uniformely susceptible to cefotaxime and ceftriaxone. The high rate of nasopharyngeal carriage of Streptococcus pneumoniae along with the resistance to antibiotics widely used in the community suggests the importance of epidemiological surveillance as well as the application of new vaccine strategies.

BCG septicemia after radical cystectomy: a rare postoperative complication following BCG therapy.

It is reported a case of life-threatening septic shock due to BCG septicemia after radical cystectomy in a patient with a previous treatment with BCG therapy. In the absence of response to standard antimicrobial therapy and a negative CT scan, a PCR-based technique detected the presence of BCG bacilli in bloodstream. Immediate antimycobacterial therapy resolved the sepsis, thus suggesting either the awareness of this infection or the prompt antimycobacterial therapy as the key for the appropriate management. Furthermore, isoniazid prophylaxis should be taken into consideration in patients with history of intravesical BCG therapy undergoing cystectomy.

"Matrioska head". Case report of calcified chronic subdural hematoma.

We report an asymptomatic case of a large calcified chronic subdural hematoma (CCSH). Skull X-ray examination, computer tomography (CT) and magnetic resonance imaging (MRI), showed an adhering calcification extending to the whole cerebral cortex, as if the skull had another concentric skull inside it. These radiological findings recall the famous Russian doll named "Matrioska"; for this reason we defined this case "Matrioska head". The patient was absolutely asymptomatic and we discuss the causes that may give the calcification of chronic subdural hematoma (CSH).

Seroprevalence of chronic Chlamydia pneumoniae infection in patients affected by chronic stable asthma.

OBJECTIVE: To evaluate the seroprevalence of Chlamydia pneumoniae and age, gender and smoking habits in stable asthmatic patients. METHODS: Over a period of 3 months, 197 adult patients affected by intermittent-to-severe chronic asthma were enrolled from 16 respiratory disease units in the south of Italy. As a control group, we tested 185 healthy, non-asthmatic subjects matched for age and gender, recruited among hospital staff. All patients were submitted to clinical examination, spirometry and blood collection for C. pneumoniae serology. The presence of infection was investigated by microimmunofluorescence (Micro-IF Test) for C. pneumoniae-specific IgG, IgM and IgA antibodies. RESULTS: C. pneumoniae IgG titers > or =1 : 64 were detected in 30.4% of asthmatics and in 30.8% of controls. Correlation of age, gender and smoking habit with C. pneumoniae seropositivity was evaluated by linear regression analysis. Age was significantly associated with C. pneumoniae IgG titer > or =1 : 64 when seropositive asthmatics were tested. Moreover, C. pneumoniae seroprevalence was higher among smokers with a diagnosis of chronic asthma. CONCLUSIONS: The seroprevalence of C. pneumoniae in stable asthmatics was comparable with the controls; therefore, the study does not support the association between C. pneumoniae antibody titers and stable asthma. However, the analysis for likely confounders such as age, gender and smoking status suggests a possible association of enhanced susceptibility to C. pneumoniae infection with age and smoking habitus.

Antibiotic prescribing for dental conditions: a community-based study in southern Italy.

The aim of this study was to investigate for which conditions antibiotics are being used in community dental practice, and which clinical features represent the most common reason for an antibacterial approach to the treatment of dental conditions. The study was carried out from November 1998 to June 1999. Dentists were selected according to the different areas of southern Italy, from a list provided by the Italian Society of Dentists. Out of 87 selected dentists, 33 agreed to participate and filled in 1615 questionnaires for each therapeutic intervention ending with antibiotic treatment. Analysis of data indicated that alveolar-gingival abscesses were the most commonly treated infection, accounting for 23.6% of total treatments, followed by acute periodontitis (20.6%) and disodontiasis of the 3rd molar (18.5%). Parenteral antibiotics were chosen in 7.8% of cases. Penicillins were the most commonly used group, 40.1% of total treatments, followed by macrolides (30.2%) and cephalosporins (13.4%). Moreover, penicillins were widely used for post-surgery therapy (52.1%) and disodontiasis of the 3rd molar (50.8%), while macrolides were the most commonly used group for gingivitis (44.1%) and parodontal diseases (55.0%). The choice of parenteral antibiotics was related to severe general symptoms (odds ratios [OR], 4.4; 95% CI: 2.2-9.0), pain (OR, 2.7; 95% CI: 1.2-6.1) and lymphonodal involvement (OR, 6.4; 95% CI: 2.7-15.1). In conclusion, our study demonstrates that antibiotic treatment is often based on the eradication of as many microorganisms as possible, and on the clinical assessment of the patients, rather than on any knowledge of the pathogens involved.

Bacterial agents of lower respiratory tract infections (LRTIs), beta-lactamase production, and resistance to antibiotics in elderly people. DEDALO Study Group.

This study determined the etiology of lower respiratory tract infections in the elderly and assessed whether the growth of beta-lactamase producing bacteria is particularly favoured in these patients. Between December 1998 and May 1999, 187 patients with community-acquired pneumonia (CAP), and 887 patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) were enrolled. The mean age was 74 years (range of 65-94 year). Sputum and bronchial aspirate for microbiological investigation were obtained. Besides organisms commonly involved in bacterial infections of the lower respiratory tract (i.e. Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis), Enterobacteriaceae and Pseudomonas spp. were also found. A high percentage of these bacteria were beta-lactamase producers. These data along with the clinical presentation, severity of infection, and epidemiological knowledge, might represent a guide for the choice of empiric antimicrobial treatment.

Polymerase chain reaction detection of Bartonella henselae bacteraemia in an immunocompetent child with cat-scratch disease.

UNLABELLED: A case of Bartonella henselae bacteraemia is reported in an immunocompetent 8-year-old boy with cat-scratch disease. Serology to B. henselae, diagnosed by polymerase chain reaction, was positive. DNA was extracted from peripheral whole blood and amplified with specific primers targeting the htrA gene of B. henselae. A non-isotopic hybridization assay with a species-specific oligonucleotide probe was used to detect the amplified product. CONCLUSION: The polymerase chain reaction can be used for the rapid laboratory diagnosis of bacteraemia in cat-scratch disease.

Detection of Bartonella henselae and Afipia felis DNA by polymerase chain reaction in specimens from patients with cat scratch disease.

Polymerase chain reaction (PCR) amplification and colorimetric identification of amplicons were performed to detect Bartonella henselae and Afipia felis DNA in specimens from patients who were clinically and histologically suspected of having cat scratch disease. PCR products were revealed using 2% ethidium bromide agarose-gel electrophoresis and identified with specific probes in a commercial colorimetric hybridization assay (DEIA) (GEN-ETI-K; DiaSorin, Italy). Six paraffin-embedded lymph node biopsies from 18 patients as well as 18 samples of peripheral whole blood and 18 sera were investigated. Bartonella henselae DNA was recovered from the whole blood of four patients, and Bartonella henselae and Afipia felis DNA were detected in one patient's lymph node biopsy. This study suggests that PCR-DEIA is sufficiently sensitive to be considered feasible for the molecular diagnosis of cat scratch disease.

Prevalence of antibodies to Bartonella henselae in patients with suspected cat scratch disease (CSD) in Italy.

Cat scratch disease (CSD) is a relatively new diagnosed illness with clinical signs of self-limiting regional lymphadenopathy accompanied by symptoms of fever and malaise, to encephalopathy and neuropathy, occurring after a cat scratch or flea bite. Bartonella henselae is now accepted as the etiologic agent of CSD. From January 1994 to September 1998, 412 patients were evaluated for suspect CSD in Italy. Sera were tested for antibodies to B. henselae by a commercially available indirect immunofluorescent assay (IFA), based on B. henselae-infected Vero-cells as the antigen substrate. Of the 412 patients, 26 (6.3%) were considered positive having titers of immunoglobulin G (IgG) to B. henselae of 64 or higher. In these patients CSD was indeed confirmed by either histopathologic examination of lymph nodes biopsy or fourfold raise in antibody titers. Nevertheless, sera were tested by IFA for Afipia felis and one showed a double reactivity to B. henselae and A. felis. Finally, three sera, negative to B. henselae serology, were positive to A. felis. Three hundred and eighty-six patients received alternative diagnoses. One hundred and twenty-five serum samples from control subjects were negative by IFA for either B. henselae or A. felis. Moreover, a cross-reactivity with sera from patients affected by other diseases was not observed. Our study shows that the ascertained cases of CSD are etiologically determined by B. henselae, IFA assay is confirmed as a useful tool in the laboratory diagnosis and, over a 5 years period of study, the incidence of CSD in Italy has been low.

Detection of anti-lipoarabinomannan antibodies for the diagnosis of active tuberculosis.

SETTING: A serological test that contributes in diagnosing tuberculosis would aid patient management. OBJECTIVE: To evaluate MycoDot, a new commercially available serological test, for the detection of immunoglobulin G antibodies to lipoarabinomannan (LAM), a glycolipid common to mycobacteria. DESIGN: Serum samples from 102 non-human immunodeficiency virus (HIV)-infected patients with no previous history of tuberculosis and with suspected active pulmonary (66) and/or extra-pulmonary (36) tuberculosis were investigated; 50 HIV-negative healthy subjects, sputum culture-negative, tuberculin skin test negative and with no history of tuberculosis, were used as controls. RESULTS AND CONCLUSION: In 28 patients with microbiologically ascertained tuberculosis 25/28 serum samples were positive, whereas the test was negative in two patients with renal tuberculosis and in one with pulmonary tuberculosis. The remaining 74 serum samples were negative. The follow-up of these patients excluded a mycobacterial infection. Control subjects were negative. On the basis of our design, the MycoDot test, with its rapidity and degree of sensitivity, is suitable for routine use in laboratory diagnosis of both pulmonary and extrapulmonary tuberculosis.

Cellular fatty acid composition, soluble-protein profile, and antimicrobial resistance pattern of Eubacterium lentum.

Phenotypic heterogeneity among isolates of Eubacterium lentum has been recognized for many years. To better delineate their taxonomic relatedness, 29 clinical isolates of E. lentum were examined for soluble-protein content, cellular fatty acid profile, and antimicrobial resistance pattern in order to ascertain whether differences in these characteristics could be correlated with differences in biochemical activities. Among 29 isolates we could identify 6 that were different from all the others. These strains were coccobacilli with translucent colonies; they were catalase and H2S negative, not fluorescent under UV light, and susceptible to beta-lactam drugs; growth was not stimulated by arginine; and fatty acid analysis revealed the presence of straight-chain fatty acids. The remainder of the strains, including the type species, were pleomorphic bacilli with speckled colonies and were catalase and H2S positive; all but two were fluorescent under UV light; they were resistant to beta-lactam antibiotics; growth was greatly stimulated by arginine; and they demonstrated saturated branched-chain fatty acids. Our data suggest that E. lentum can be further differentiated into different types.

Detection of Mycobacterium tuberculosis DNA in blood of patients with acute pulmonary tuberculosis by polymerase chain reaction and non-isotopic hybridisation assay.

The detection of Mycobacterium tuberculosis DNA in peripheral blood mononuclear cells (PBMC) by PCR and non-isotopic hybridisation assay was evaluated for the laboratory diagnosis of pulmonary M. tuberculosis infection. The PCR technique was based on the presence of IS6110, a DNA sequence specific for M. tuberculosis, and performed on PBMC from 30 patients belonging to the fifth group of the American Thoracic Society (ATS) classification of tuberculosis. The identification of amplification products was confirmed after electrophoresis by hybridisation with a non-isotopic probe in a DNA enzyme immunoassay (DEIA). Of the 30 blood samples studied by the PCR-DEIA technique, 26 gave positive results and four gave negative results. Blood samples from 30 subjects in a control group were negative by this technique. The data suggest that PCR-DEIA of blood may provide a sensitive, specific and useful means of diagnosing mycobacterial infection.