Infect. Dis. Rep., Volume 4, Issue 2 (April 2012) – 12 articles

Zoonotic infections are on the increase worldwide, but most research into the biological, environmental and life science aspects of these infections has been conducted in separation. In this review we bring together contemporary research in these areas to suggest a new, symbiotic framework which recognises the interaction of biological, economic, psychological, and natural and built environmental drivers in zoonotic infection and transmission. In doing so, we propose that some contemporary debates in zoonotic research could be resolved using an expanded framework which explicitly takes into account the combination of motivated and habitual human behaviour, environmental and biological constraints, and their interactions. Full article

Infections caused by Pseudomonas aeruginosa are becoming more common and increasingly more difficult to treat due to the continued development of drug resistance. While sensitivity to colistin (polymyxin E) is well known, it is frequently avoided due to concerns of nephrotoxicity. Reported here is a case of a multi-drug resistance pseudomonal typhlitis, bacteremia and pleural cavity infection that required significant intensive care, and serial abdominal washouts. Intra-peritoneal tobramycin in combination with broad-spectrum intravenous antibiotics including colistin were used. Several instillations of tobramycin into the abdominal cavity along with concomitant IV administration of colistin, ceftazidime and tobramycin and per os colistin, tobramycin and nystatin resulted in the clearance of the pseudomonal infection without any evidence of toxicity from the treatment. Intra-abdominal tobramycin with parenteral colistin therapy can be used in complicated clinical settings with appropriate nephroprotection. Full article

We evaluated diagnostic yield of third sputum smear in patients co infected with HIV for detection of pulmonary tuberculosis. Among 139 pulmonary tuberculosis cases confirmed with positive sputum culture, diagnostic yield of first smear of sputum with acid fast staining was 83.5%. Incremental yield of 2nd and 3rd samples was 11.2% and 5.2% respectively. So two sputum smears may be enough for primary evaluation of HIV infected patients suspected to TB. Full article

Klebsiella pneumoniae is a major cause of nosocomial pneumonia, septicemia and urinary tract infections, especially in newborns, blood cancer patients, and other immunocompromised candidates. The control of K. pneumoniae is a complicated issue due to its tight pathogenesis. Immuno-prophylactic preparations, especially those directed toward the bacterium O-antigen, showed to be the most successful way to prevent the infection incidence. However, all previously proposed preparations were either of limited spectrum or non-maternal, and hence not targeting the main Klebsiella patients. Moreover, all preparations were directed only to prevent the respiratory diseases due to that pathogen. This article addresses the development of a method originally used to purify the non-capsular bacterial- endotoxins, as a new and easy method for vaccine production against K. pneumoniae. The application of this method was preceded by a biotechnological control of capsular polysaccharide production in K. pneumoniae. The new produced natural conjugate between the bacterial O-antigen and its outer membrane proteins was evaluated by physicochemical and immunological methods to investigate its purity, integrity, safety and immunogenicity. It showed to be pure, stable, safe for use, and able to elicit a protective immunoglobulin titer against different Klebsiella infections. This immune-response proved to be transferable to the offspring of the vaccinated experimental rabbits via placenta. Full article

We sought to determine predictors of shingles reports in adults with common variable immunodeficiency or immunoglobulin (Ig) G subclass deficiency (CVID/IgGSD). We tabulated observations at diagnosis of CVID/IgGSD in 212 white adult index patients (165 women, 47 men) who responded to a question about having had shingles. None had been vaccinated for herpes zoster. We analyzed age, sex, and shingles reports; blood levels of CD19+, CD4+, CD8+, and CD56+ mononuclear cells; serum levels of IgG subclasses, IgA, and IgM; and positivity for human leukocyte antigen (HLA)-A and -B haplotypes. Cell counts and immunoglobulin levels were normalized with loge (ln) transformation for analyses. Thirty-one patients (14.6%) reported shingles; 11 reported recurrent or disseminated shingles. Patients with shingles reports had greater mean age at diagnosis of CVID/IgGSD [54±13 (standard deviation) years vs. 47±12 years; P=0.0130] and a greater prevalence of HLA-A*01, B*08 positivity (35.5% vs. 17.7%; P=0.0227). In a 13-factor logistic regression model, there was a positive association of age with shingles reports [P=0.0151; odds ratio (1.05, 95% confidence interval 1.01, 1.08)]. HLA-A*01, B*08 positivity was also positively associated with shingles reports [P=0.0480; odds ratio 2.61 (1.00, 6.81)]. During a mean followup interval of 7.5 years after CVID/IgGSD diagnosis, the prevalence of recurrent shingles was almost five-fold greater in patients with previous shingles reports. In conclusion, in white adults at CVID/IgGSD diagnosis, age at diagnosis and positivity for HLA-A*01, B*08 have significant positive associations with reports of previous shingles. Full article

Cases of chronic or prolonged hepatitis E virus (HEV) infections have been described in solid organ transplant recipients, HIV infected patients and in patients with malignancies or idiopathic CD4+ T lymphopenia. It is unknown if HEV infection also takes chronic courses in patients with common variable immunodeficiency (CVID). We studied a cohort of 73 CVID patients recruited in a low endemic Central European country. None of the subjects tested positive for HEV RNA or anti-HEV IgG. Immunoglobulin transfusions (n=10) tested negative for HEV RNA but all were anti-HEV positive. To verify that such pooled blood products contain anti-HEV protective antibodies we measured the anti-HEV IgG optical density (OD) values in patients before and after transfusion. Anti-HEV OD values increased after infusion but did not reach the cut-off considered as positive. Thus, chronic HEV infections seem to be rare events in CVID patients in Germany. Commercially available immuno globulin infusions contain anti HEV antibodies and may contribute to protection from HEV infection Full article

Pasteurella multocida is a rare cause of infective endocarditis with only a few cases described. This report involves a 38-year-old penicillin-allergic patient in an immunocompromised state with several co-morbidities. Two molecular microbiological techniques, 16S rRNA sequencing and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry were used to confirm the species identification as P. multocida. Previous reports in the literature are also reviewed. Full article

Leuconostoc lactis is a recognised cause of infection in immunocompromised hosts. It is intrinsically resistant to multiple antibiotics and treatment options may be limited. We report the safe and effective use of tigecycline in the treatment of Leuconostoc catheter-related line sepsis in a neutropenic patient. To our knowledge, this is the first reported case of successful use of tigecycline for Leuconostoc bacteremia. Full article

Entamoeba histolytica is a protozoan that causes amoebiasis. Recent studies demonstrated that natural killer T lymphocytes (NKT) are critical for preventing the development of amoebic liver abscess. In spite of that, there are only a handful of studies in the area. Herein, we explored the role of NKT cells in E. histolytica infection using C57BL/6 wild-type and CD1-/- mice. Animals were inoculated with E. histolytica and sacrificed 48 hours later to collect caecum samples that were used for quantitative analyses of lesions, trophozoites, NK1.1+ T lymphocytes and expression of the mucus protein MUC-2 by immunohistochemistry technique. Quantitative analyses confirmed that the frequency of NK1.1+ T cells was significantly lower in samples from C57BL/6 CD1-/- mice as compared to their wild type (WT) counterparts. The extension of necrotic mucosa was larger and the number of trophozoites higher in Entamoeba (Eh)-infected CD1-/- mice when compared with Eh-infected WT mice. In mice from both groups, noninfected (CTRL) and Eh-infected CD1-/-, there was a reduction in the thickness of the caecal mucosa and in the MUC-2-stained area in comparison with CTRL- and Eh-WT mice. Our results showed that NKT lymphocytes contribute to resistance against Entamoeba histolytica infection and to the control of inflammation in the colitis induced by infection. The presence of a normal epithelial layer containing appropriate levels of mucus had also a protective role against infection. Full article

In order to determine HIV-1 kinetics in cerebrospinal fluid (CSF) and plasma in patients with cryptococcal meningitis (CM), we undertook a prospective collection of paired CSF/plasma samples from antiretroviral therapy- free HIV-infected patients with CM. Samples were obtained at baseline (S1) and at the second (S2) and third (S3) weeks of antifungal therapy. HIV-1 CSF concentrations were significantly lower in both S2 and S3 with respect to S1. Plasma concentrations remained stable. HIV-1 concentrations were higher in plasma than CSF in all cases. Patients who survived the episode of CM (but not those who died) showed a decrease in CSF viral load, what suggests different viral kinetics of HIV-1 in the CSF according to the clinical course of this opportunistic disease. Full article

Streptococcus pneumoniae remains an important cause of bacteremia worldwide. Last years, a decrease of S. pneumoniae penicillin-resistant isolates has been observed. The objective of this study was to describe the episodes of bacteremia due to S. pneumoniae during a period of 11 years. Epidemiological and clinical data, serotypes causing bacteremia, antibiotic susceptibility and prognosis factors were studied. Over a period of 11 years, all the episodes of S. pneumoniae bacteremia were analysed. Their clinical and microbiological features were recorded. Statistical analysis was carried out to determine risk factors for pneumococcal bacteremia and predictors of fatal outcome. Finally, 67 S. pneumoniae bacteremia episodes were included in this study. The majority of cases were produced in white men in the middle age of their life. The main predisposing factors observed were smoking, antimicrobial and/or corticosteroids administration, chronic pulmonary obstructive disease and HIV infection, and the most common source of bacteremia was the low respiratory tract. The main serotypes found were 19A, 1, 14 and 7F. Seventy-seven percent of these isolates were penicillin-susceptible, and the mortality in this serie was really low. Statistical significance was observed between age, sex and race factors and the presence of bacteremia, and there was relationship between the patient’s condition and the outcome. In our study, S. pneumoniae bacteremia is mainly from community-acquired origin mainly caused in men in the median age of the life. 40% of bacteremias were caused by serotypes 19A, 1, 7F and 14. During the period of study the incidence of bacteremia was stable and the mortality rate was very low. Full article

Contact investigations around tuberculosis patients enable early detection of infection and disease, and prevention of secondary tuberculosis cases. We aim to identify risk factors for M. tuberculosis transmission to contacts of tuberculosis patients, based on unique data from routine contact investigations by the Public Health Service in Rotterdam, the Netherlands, collected between 2001 and 2006. Through logistic regression analysis, we determined the effect of various risk factors on the chance of finding a latent tuberculosis (TB) infection or overt tuberculosis case among contacts. A total of 1165 index patients with active tuberculosis were registered and at least one contact was investigated in 731, resulting in 21,540 contacts overall. Altogether, the contact investigations led to 91 cases of active tuberculosis. Of the 12,698 contacts eligible for screening by tuberculin skin test, 1091 (9%) were diagnosed with latent tuberculosis infections. Risk factors were old age of the contact, old age of the index patient, and the relationship to the index. A larger fraction of infected close contacts was strongly associated with infections among more distant contacts. Our findings emphasize the importance of including these personal and interpersonal risk factors in decision making in contact investigations. Full article