European Journal of Clinical Microbiology Infectious Diseases

Eyre, D.; Kenkre, J.; Bowler, I.; McBride, S.

doi: 10.1007/s10096-010-1037-5pmid: 20820836

A case is described of a 79-year-old man, trampled by his horses, who subsequently developed a wound infection and, later, meningitis. Streptococcus equi subsp. zooepidemicus was isolated as the causative organism. S. equi subsp. zooepidemicus, which carries the Lancefield Group C antigen, is an uncommon human pathogen but is commonly isolated from bacterial infections in animals, particularly horses. It is most commonly acquired by humans following animal contact. A review of the literature identified 20 previously described cases of S. equi subsp. zooepidemicus meningitis. Crude mortality following infection was 24%. All of the patients who died were over 70 years of age and the ingestion of unpasteurised dairy products was associated with all but one of the fatal cases. Hearing loss was a frequent complication, occurring in 19% of cases. Only 38% of patients made a complete recovery. Treatment regimes commonly included benzylpenicillin or a third-generation cephalosporin, with a mean treatment duration in survivors of 23 days.

Porto, A.; Lammers, A.; Bennink, R.; Berge, I.; Speelman, P.; Hoekstra, J.

doi: 10.1007/s10096-010-1049-1pmid: 20853172

Hyposplenic patients are at risk of overwhelming post-splenectomy infection (OPSI), which carries mortality of up to 70%. Therefore, preventive measures are warranted. However, patients with diminished splenic function are difficult to identify. In this review we discuss immunological, haematological and scintigraphic parameters that can be used to measure splenic function. IgM memory B cells are a potential parameter for assessing splenic function; however, more studies are necessary for its validation. Detection of Howell–Jolly bodies does not reflect splenic function accurately, whereas determining the percentage of pitted erythrocytes is a well-evaluated method and seems a good first-line investigation for assessing splenic function. When assessing spleen function, 99mTc-labelled, heat-altered, autologous erythrocyte scintigraphy with multimodality single photon emission computed tomography (SPECT)-CT technology is the best approach, as all facets of splenic function are evaluated. In conclusion, although scintigraphic methods are most reliable, they are not suitable for screening large populations. We therefore recommend using the percentage of pitted erythrocytes, albeit suboptimal, as a first-line investigation and subsequently confirming abnormal readings by means of scintigraphy. More studies evaluating the value of potentially new markers are needed.

Shime, N.; Kosaka, T.; Fujita, N.

doi: 10.1007/s10096-010-1024-xpmid: 20711623

The purpose of this investigation was to examine the impact of antimicrobial regimens administered for hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia on the all-cause, 14-day mortality. We retrospectively examined the characteristics of the most effective empiric antimicrobial therapy in 87 consecutive patients, hospitalised at a single institution between April 2003 and March 2008, who presented with clinically and microbiologically confirmed MRSA bacteraemia. The all-cause mortality was measured 14 days after the diagnosis was made. The administration of an effective antimicrobial against MRSA <48 h after the collection of blood cultures was the single, significant predictor of survival (odds ratio 3.85; 95% confidence interval 1.37–10.80; p = 0.01). The survival of patients treated with vancomycin versus other antimicrobial agents was similar. Among subgroups treated with vancomycin, the lowest mortality (6%) was observed among patients treated (a) within 48 h after the collection of blood cultures and (b) with doses sufficient to keep the blood concentrations in the area under the 0–24 h curve >400 μg h/ml (≥2.0 g/day). The empiric administration of antimicrobials effective against MRSA bacteraemia within 48 h after the collection of blood cultures increased the 14-day survival. If vancomycin is chosen, ≥2.0 g/day should be administered, starting within 48 h.

Madhumathi, J.; Pradiba, D.; Prince, P.; Jeyaprita, P.; Rao, D.; Kaliraj, P.

doi: 10.1007/s10096-010-1026-8pmid: 20803227

Lymphatic filariasis is a tropical disease, with over 40 million people seriously incapacitated due to lymphangitis and elephantiasis. Over 99% of infections are caused by the nematode Wuchereria bancrofti. Expressed sequence tag (EST) analysis of filarial genome identified novel infective larval (L3) stage-specific antigen, abundant larval transcript (ALT-2), which was shown to be highly essential for parasite establishment and survival in the host. The unique structural features and immunological characteristics of ALT-2 indicate the presence of critical motifs that needs to be explored in natural human infection for understanding and management of the disease. In order to dissect the epitopes of ALT protein recognized in humans, eight peptides spanning the entire protein sequence were selected based on in-silico epitope prediction and synthesized. Analysis of the reactivity of W. bancrofti ALT-2 synthetic peptides with clinical sera (n = 40) from endemic areas identified epitopes recognized by putatively immune sera, of which two comprise the highly variable acidic domain (21–60). Interestingly, our study also revealed crucial epitopes recognized by microfilaremic (MF) sera with significantly high IgG4 isotype (p < 0.001), implicated in immunomodulation. The epitope peptides identified were highly specific for MF sera and, thus, have the potential to be exploited as diagnostic markers.

Zhang, M.; Li, Q.; Zhang, X.-Y.; Ding, X.; Zhu, D.; Zhou, X.

doi: 10.1007/s10096-010-1027-7pmid: 20725845

The objective of this investigation was to verify the hypothesis that the presence of lower airway bacterial colonization (LABC) can be a stimulating factor of airway inflammation, more frequent exacerbation, and impact on pulmonary function, independent of current tobacco smoking in the stable phase of chronic obstructive pulmonary disease (COPD). A total of 46 ex-smokers with moderate to severe COPD, 19 healthy non-smokers, and 17 ex-smokers without COPD were included in this study. Their sputum specimens were collected at the first baseline visit and at the second visit after a follow-up of one year. The samples were analyzed for bacterial growth by culture, and the levels of interleukin (IL)-6, IL-8, and tumor necrosis factor alpha (TNF-α) were measured by enzyme-linked immunosorbent assay (ELISA). The frequencies of exacerbations and pulmonary function were compared at visit 2. At visit 1, 37.0% (17/46) were found to have LABC with bacterial loads ≥106 CFU/ml in their sputum specimens. Haemophilus influenzae was the predominant pathogenic organism isolated. IL-8, IL-6, and TNF-α in these patients’ sputum were significantly higher than those without LABC (p < 0.05). It was the presence of LABC that contributed to the significantly elevated IL-8 and IL-6 at the 1-year period (p < 0.05). LABC was also associated with significantly increased frequencies of exacerbations and declined forced expiratory volume in 1 s (FEV1) (p < 0.05). LABC was documented in a subpopulation of stable COPD patients; it may be responsible for the deterioration of pulmonary function of COPD patients by promoting airway inflammation and/or increased frequency of exacerbations independently of tobacco smoking.

Roy, S.; Viswanathan, R.; Singh, A.; Das, P.; Basu, S.

doi: 10.1007/s10096-010-1030-zpmid: 20730467

Infections caused by Acinetobacter baumannii are a threat to neonates because of its resistance to antimicrobials, including carbapenems. In 2007, A. baumannii emerged as an important aerobic Gram-negative bacillus (12.5%, 4/32) that caused sepsis in our unit. A. baumannii from the gut of the neonates was analyzed, as this could be indicative of the antibiotic resistance of the organisms. The study attempts to understand the gut colonization with multidrug-resistant A. baumannii among hospitalized neonates with special reference to carbapenem resistance. A. baumannii was found in the gut of 11% of babies. Interestingly, 60.7% (17/28) and 21.4% (6/28) of the isolates from the gut were multidrug-resistant and carbapenem-resistant, respectively. The number of multidrug-resistant and carbapenem-resistant isolates from blood cultures were 3/4 and 1/4, respectively. The study reports for the first time OXA-23 and OXA-58 carbapenemases in A. baumannii from India. Pulsed field gel electrophoresis (PFGE) patterns indicated that the strains were diverse and no epidemic clone existed. Though A. baumannii gut colonization could not be implicated as a risk factor for subsequent sepsis, the high rate of isolation of multidrug-resistant and carbapenem-resistant isolates indicates that these therapeutic options might be drastically reduced among neonates in the future.

Kennedy, K.; Collignon, P.

doi: 10.1007/s10096-010-1031-ypmid: 20835879

Antimicrobial resistance among community-acquired isolates of Escherichia coli is increasing globally, with international travel emerging as a risk for colonisation and infection. The aim was to determine the rate and duration of colonisation with resistant E. coli following international travel. One hundred and two adult hospital staff and contacts from Canberra, Australia, submitted perianal/rectal swabs before and following international travel. Swabs were cultured selectively to identify E. coli resistant to gentamicin, ciprofloxacin and/or third-generation cephalosporins. Those with resistant E. coli post-travel were tested monthly for persistent colonisation. Colonisation with antibiotic-resistant E. coli increased significantly from 7.8% (95% confidence interval [CI] 3.8–14.9) pre-travel to 49% (95% CI 39.5–58.6) post-travel. Those colonised were more likely to have taken antibiotics whilst travelling; however, travel remained a risk independent of antibiotic use. Colonisation with resistant E. coli occurred most frequently following travel to Asia. While over half of those carrying resistant E. coli post-travel had no detectable resistant strains two months after their return, at least 18% remained colonised at six months. Colonisation with antibiotic-resistant E. coli occurs commonly after international travel, and can be persistent. Medical practitioners should be aware of this risk, particularly when managing patients with suspected Gram-negative sepsis.

Han, Qunying; Zhang, Lei; Liu, Zhengwen; Kang, Wen; Lou, Sai; Qiu, Jianming; Li, Zhu; Zhang, Guoyu; Wang, Yawen; Li, Man; Li, Na

doi: 10.1007/s10096-010-1032-xpmid: 20725844

Pliaka, V.; Kyriakopoulou, Z.; Tsakogiannis, D.; Ruether, I.; Gartzonika, C.; Levidiotou-Stefanou, S.; Krikelis, A.; Markoulatos, P.

doi: 10.1007/s10096-010-1033-9pmid: 20820837

Attenuated strains of Sabin poliovirus vaccine replicate in the human gut and, in rare cases, may cause vaccine-associated paralytic poliomyelitis (VAPP). The genetic instability of Sabin strains constitutes one of the main causes of VAPP, a disease that is most frequently associated with type 3 and type 2 Sabin strains, and more rarely with type 1 Sabin strains. In the present study, the growth phenotype of eight oral poliovirus vaccine (OPV) isolates (two non-recombinants and six recombinants), as well as of Sabin vaccine strains, was evaluated using two different assays, the reproductive capacity at different temperatures (Rct) test and the one-step growth curve test in Hep-2 cells at two different temperatures (37°C and 40°C). The growth phenotype of isolates was correlated with genomic modifications in order to identify the determinants and mechanisms of reversion towards neurovirulence. All of the recombinant OPV isolates showed a thermoresistant phenotype in the Rct test. Moreover, both recombinant Sabin-3 isolates showed significantly higher viral yield than Sabin 3 vaccine strain at 37°C and 40°C in the one-step growth curve test. All of the OPV isolates displayed mutations at specific sites of the viral genome, which are associated with the attenuated and temperature-sensitive phenotype of Sabin strains. The results showed that both mutations and recombination events could affect the phenotype traits of Sabin derivatives and may lead to the reversion of vaccinal strains to neurovirulent ones. The use of phenotypic markers along with the genomic analysis may shed additional light on the molecular determinants of the reversed neurovirulent phenotype of Sabin derivatives.

Mendes, F.; Oliveira, L.; Faria, E.; Alvarenga, D.; Pinto, M.; Taborda, C.; Soares, B.; Cisalpino, P.; Santos, D.

doi: 10.1007/s10096-010-1034-8pmid: 20803047

Forty Cryptococcus gattii strains were submitted to antifungal susceptibility testing with fluconazole, itraconazole, amphotericin B and terbinafine. The minimum inhibitory concentration (MIC) ranges were 0.5–64.0 for fluconazole, <0.015–0.25 for itraconazole, 0.015–0.5 for amphotericin B and 0.062–2.0 for terbinafine. A bioassay for the quantitation of fluconazole in murine brain tissue was developed. Swiss mice received daily injections of the antifungal, and their brains were withdrawn at different times over the 14-day study period. The drug concentrations varied from 12.98 to 44.60 μg/mL. This assay was used to evaluate the therapy with fluconazole in a model of infection caused by C. gattii. Swiss mice were infected intracranially and treated with fluconazole for 7, 10 or 14 days. The treatment reduced the fungal burden, but an increase in fungal growth was observed on day 14. The MIC for fluconazole against sequential isolates was 16 μg/mL, except for the isolates obtained from animals treated for 14 days (MIC = 64 μg/mL). The quantitation of cytokines revealed a predominance of IFN-γ and IL-12 in the non-treated group and elevation of IL-4 and IL-10 in the treated group. Our data revealed the possibility of acquired resistance during the antifungal drug therapy.