Prevalence of <Emphasis Type="Italic">Blastocystis hominis</Emphasis> and <Emphasis Type="Italic">Strongyloides stercoralis</Emphasis> infection in Okinawa,Japan

This study was conducted to clarify the prevalence of Blastocystis hominis and Strongyloides stercoralis infection in Ryukyu University Hospital, Okinawa, Japan, between January 2004 and November 2006. Stool samples collected from 3,292 patients were examined by the direct smear method, formalin–ether sedimentation method, and agar plate culture method. The prevalence rate of B. hominis and S. stercoralis infection was 1.0 and 3.4%, respectively. The prevalence rate of B. hominis infection in patients aged >80 years old was significantly higher than that in patients <80 years old (P < 0.001). The prevalence rate of S. stercoralis infection was significantly higher in patients with B. hominis infection compared with those without (P < 0.001). This study demonstrated a prevalence rate for B. hominis and S. stercoralis infection and an association between B. hominis and S. stercoralis infection in Okinawa, Japan.     

Epidemiology of invasive neonatal <Emphasis Type="Italic">Cronobacter</Emphasis> (<Emphasis Type="Italic">Enterobacter sakazakii</Emphasis>) infections

About 120–150 neonatal Cronobacter spp. (Enterobacter sakazakii) infections have been described. An analysis of current case numbers, epidemiological measures and risk factors is warranted. Data of microbiologically confirmed cases, published between 2000 and 2008, have been analysed statistically. More than 100 neonatal Cronobacter infections have been reported in this period. The overall lethality of the 67 invasive infections was 26.9%. The lethality of Cronobacter meningitis, bacteraemia and necrotising enterocolitis (NEC) was calculated to be 41.9% (P < 0.0001), <10% and 19.0% (P < 0.05), respectively. Logistic regression models (P < 0.0001) revealed a higher gestational age at birth and parentage not from Europe as significant factors for a higher reporting probability of neonatal Cronobacter meningitis. Neonates with Cronobacter meningitis not originating from North America have a higher risk for lethal outcome than other neonatal Cronobacter infections (P < 0.0001). Continental differences of risk factors for Cronobacter meningitis and for the lethal outcome of neonatal meningitis should be elucidated. Neonatal Cronobacter infections are mainly associated with the contamination of infant formula and of the relevant cleaning and preparation equipment. Eleven neonatal Cronobacter infections, not caused by contaminated infant formula, have been retrieved. Other environmental sources of infection should be considered. Consistent and sufficiently informative data of invasive neonatal Cronobacter infections should be recorded in a centralized reporting system.     

Detection of <Emphasis Type="Italic">Helicobacter pylori</Emphasis>, <Emphasis Type="Italic">Enterococcus faecalis</Emphasis>, and <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> in the subgingival biofilm of HIV-infected subjects undergoing HAART with chronic periodontitis

This study compared the frequency of Helicobacter pylori, Enterococcus faecalis, and Pseudomonas aeruginosa in the subgingival microbiota of HIV-seropositive and HIV-seronegative subjects with periodontitis or clinically healthy periodontal tissues. Fifty-four subjects were distributed into two HIV-seropositive groups (chronic periodontitis [HCP = 13] and periodontal health [HH = 10]) and two HIV-seronegative groups (chronic periodontitis [CP = 17] and periodontal health [H = 14]). The detection of bacterial species was carried out by polymerase chain reaction (PCR). CP patients showed significantly more periodontal destruction, inflammation, and supragingival plaque than HCP patients (P < 0.05). All species were detected at a higher prevalence in CP and HCP than H individuals (P < 0.01). In the HIV groups, H. pylori was significantly more prevalent in periodontitis compared to healthy patients (P < 0.01). A higher frequency of E. faecalis and P. aeruginosa was observed in the subgingival biofilm of HH than H subjects (P < 0.01). Moreover, E. faecalis was detected significantly more often in HIV-seropositive compared to HIV-seronegative patients, regardless of periodontal status (P < 0.01). These data indicate that H. pylori is frequently detected in the subgingival microbiota of periodontitis subjects. In contrast, HIV-seropositive patients with either periodontitis or periodontal health present a high prevalence of E. faecalis.     

In vitro and in vivo efficacies of amlodipine against <Emphasis Type="Italic">Listeria monocytogenes</Emphasis>

Listeria monocytogenes causes suppurative gastritis in BALB/c mice. We investigated the effect of the antihypertensive drug amlodipine (Aml) on the growth of L. monocytogenes in vitro and in vivo. Aml showed noteworthy inhibitory action (minimum inhibitory concentration, MIC₉₀ 32 μg/ml) against Listeria strains and demonstrated cidal (minimum bactericidal concentration, MBC 64 μg/ml) activity. Aml administered orally at 2.5 μg/g in female BALB/c mice for 7 days, commencing 4 days before oral challenge (1 × 10⁸ CFU/ml with L. monocytogenes ATCC 51774), significantly reduced bacterial counts in the stomach (P < 0.01), liver (P < 0.01), and spleen (P < 0.05), and decreased (P < 0.05) gastric lesions, neutrophilic infiltration, edema, vascular degeneration, and necrosis of gastric tissues. It caused the down-regulation of expression of inflammatory cytokines (IFN-γ, IL-1β, and TNF-α) compared to drug-free control. Aml may be used in the presence of an antibiotic as adjunct therapy that boosts the host immunity against Listeria. Further, QSAR studies might contribute in manipulating it as a lead compound for the synthesis of new, more effective non-antibiotics (helper compounds), perhaps devoid of side-effects, that could be recommended as compassionate therapy for listeriosis.     

Occupational risk of human <Emphasis Type="Italic">Cytomegalovirus</Emphasis> and <Emphasis Type="Italic">Parvovirus</Emphasis> B19 infection in female day care personnel in the Netherlands; a study based on seroprevalence

Cytomegalovirus (CMV) and Parvovirus B19 infections acquired during pregnancy may result in developmental disabilities of the foetus. This study evaluates the occupational risk of these infections in female day care personnel. IgG seroprevalence was determined in 310 Dutch day care workers and 158 nursing school students. CMV seroprevalence was age-related, starting at 21% in those <20 years and reaching 65% in those >35 years. Between the ages of 20 and 24 years the CMV prevalence was higher in day care personnel than in controls, 50% versus 31% (p = 0.03). In the first 2 years of employment the risk of attracting CMV was significantly increased (OR_adj = 3.80; p < 0.001) and the occupational risk was also increased (OR_adj 2.19; p < 0.001). Parvovirus seropositivity (71–77%) was not related to age or working at a day care centre. In conclusion, an occupational risk was observed for CMV, but not for Parvovirus infection in female day care personnel. The fieldwork was performed at the Department of Infectious Diseases, South Limburg Public Health Service. Analyses and editing were finalised at the Department of Medical Microbiology, University Hospital Maastricht.     

Reinfections and <Emphasis Type="Italic">Trypanosoma cruzi</Emphasis> strains can determine the prognosis of the chronic chagasic cardiopathy in mice

Chronic Chagas’ disease represents the result of the interaction between the host and the parasite, producing different clinical features: from a mild disease to a severe heart failure. In the present investigation, we analyzed whether Trypanosoma cruzi strain and/or reinfections in the acute stage, determine changes in the chronic phase (135 days postinfection, d.p.i) that could explain the diverse evolution of cardiac lesions. After infection of albino Swiss mice (n = 170) with 50 blood trypomastigote of the T. cruzi, strain Tulahuen (n = 80) and the isolate SGO-Z12 (n = 90), respectively, and reinfections at 10 and 20 d.p.i. Parasitemia, survival, electrocardiography, affinity and density of cardiac β-receptors and histopathology of the heart were studied. Parasitemias in reinfected mice were significantly higher than those in single-infected mice. Survival of SGO-Z12-infected group was significantly higher than the other groups (p < 0.01). All Tulahuen-reinfected mice and 55–67% of the infected and SGO-Z12-reinfected groups presented some electrocardiographic abnormality (p < 0.01). Hearts from single-infected mice presented fibber disorganization and necrosis; reinfected groups also exhibited fibber fragmentation and a diminished affinity and a higher beta-adrenergic receptors’ density than the other groups (p < 0.05). Therefore, parasite strain and reinfections determine different cardiac damage, and either (or both) of these factors are involved in the severity of the clinical picture and the prognosis of the chronic cardiac disease.     

Occurrence of <Emphasis Type="Italic">Cryptosporidium parvum</Emphasis> and <Emphasis Type="Italic">Giardia duodenalis</Emphasis> in healthy adult domestic ruminants

To determine the prevalence and intensity of infection of Cryptosporidium spp. and Giardia duodenalis in healthy adult domestic ruminants, faecal samples were collected from 379 cattle of between 3 and 13 years old, 446 sheep and 116 goats selected at random from 60 dairy farms and 38 and 20 herds, respectively, in Galicia (NW Spain). Cryptosporidium spp. oocysts were detected in 32 cows (8.4%), 24 sheep (5.3%) and in nine goats (7.7%) from, respectively, 48.3% of the farms and 34.2 and 30.0% of the herds. The intensity of infection in cows ranged between 25 and 5,924 oocysts per gram of faeces (OPG), whereas in sheep and goats, the number of oocysts shed ranged from 8–515 OPG and from 17–782 OPG, respectively. Parasitization by Cryptosporidium spp. was significantly higher (P < 0.05) in cows than in sheep and goats. G. duodenalis cysts were identified in 101 cows (26.6%), 86 sheep (19.2%) and 23 goats (19.8%) from, respectively, 96.6% of the farms and 92.1 and 90% of the herds. The number of cysts shed by cows ranged between 15 and 3,042 cyst per gram of faeces (CPG), whereas the intensity of infection in sheep and goats ranged from 16–3010 CPG and from 15–1845 CPG, respectively, and was significantly lower (P < 0.05) than in cows and sheep. The number of Cryptosporidium spp. oocysts isolated from sheep and goats was insufficient for successful polymerase chain reaction analysis. Nevertheless, gene sequence analysis of the hsp70 and 18SrRNA genes of Cryptosporidium revealed the presence of only C. parvum in faecal samples from cows. Genotyping studies of the β-giardin and glutamate dehydrogenase genes of G. duodenalis revealed mainly assemblage E of Giardia in cows, sheep and goat faecal samples. Assemblage B of G. duodenalis was also detected in one sheep sample. These animals should be considered as a possible source of cryptosporidiosis and giardiosis, thereby maintaining the infections on farms and in herds.     

Serum protein alterations in dogs naturally infected with <Emphasis Type="Italic">Toxoplasma gondii</Emphasis>

We conducted this study to describe the serum electrophoretic pattern in dogs associated with the infection of Toxoplasma gondii (T. gondii). The serum protein pattern of 25 dogs with confirmed T. gondii infection and 15 clinically healthy dogs were evaluated using native polyacrylamide gel electrophoresis. Albumin, alpha-1 globulin, alpha-2 globulin, beta globulin, and gamma globulin bands were seen from the serum electrophoresis of infected and healthy dogs. Compared to the control group, significant decreases in the mean percentages of albumin (from 46.1 ± 7.2 to 40.8 ± 4.5%, P < 0.05), alpha-1 globulin (from 3.9 ± 0.4 to 0.8 ± 0.2%, P < 0.001), alpha-2 globulin (from 9.0 ± 0.4 to 8.3 ± 0.8%, P < 0.01), and beta globulin (from 18.4 ± 1.2 to 12.1 ± 0.6%, P < 0.001) in the infected group were determined. In contrast, gamma globulin fraction was significantly higher in infected dogs (38.1 ± 4.6%) than in control dogs (22.7 ± 7.2%; P < 0.001). Moreover, significant correlations were determined between the percentages of the albumin and gamma globulin fractions and liver enzyme tests including aspartate aminotransferase and alanine aminotransferase in infected dogs; however, no correlation was observed for the other protein fractions. In conclusion, marked alterations in serum protein pattern associated with strong modifications of serum protein concentrations are in accordance with the hepatic injury as affirmed by liver enzyme tests that were demonstrated in the canine toxoplasmosis. These findings showed that serum protein electrophoresis can be used in the diagnosis and prognosis of canine toxoplasmosis as a supplementary analysis in combination with serological, clinical, and laboratory findings of this disease.     

Cloning,expression, and characterization of <Emphasis Type="Italic">Schistosoma japonicum</Emphasis> tegument protein phosphodiesterase-5

The tegument proteins of schistosomes are regarded as potential vaccine candidates and drug targets to control schistosomiasis. Nucleotide pyrophosphatase/phosphodiesterase-5 (NPP-5), which belongs to a multigene family of nucleotide pyrophosphatase/phosphodiesterases (NPPs), is important in the hydrolysis of pyrophosphate or phosphodiester bonds in nucleotides and their derivatives. In the present study, SjNPP-5, identified as one of the tegument proteins of Schistosoma japonicum in our previous proteomic studies, was cloned on a fragment of 1,371 bp and expressed as a recombinant protein of 69 kDa. Real-time RT-PCR analysis showed that SjNPP-5 was up-regulated at 21–42 days, and the expression level in 42-day-old male worms was almost nine times higher than that in females. Western blot analysis revealed that rSjNPP-5 had good antigenicity. Immunofluorescence analysis found that SjNPP-5 was a membrane-associated antigen mainly distributed on the surface of the male adult worm of S. japonicum. BALB/c mice vaccinated with rSjNPP-5 three times showed a 29.90% worm reduction (P < 0.05) and a 26.21% egg count reduction (P > 0.05). Immunization with rSjNPP-5 induced a mixed Th1/Th2 response in which Th1 was dominant. The response was characterized by a reduced IgG1/IgG2a ratio and elevated production of cytokines IFN-γ and IL-4. This study suggested that SjNPP-5 may be important in schistosome development, and further investigations are required to fully understand the function of this molecule.     

Differential larvicidal efficacy of four species of <Emphasis Type="Italic">Vitex</Emphasis> against <Emphasis Type="Italic">Culex quinquefasciatus</Emphasis> larvae

The early fourth instar larvae of Culex quinquefasciatus, reared in the laboratory were used for larvicidal assay with leaf extracts of Vitex negundo, Vitex trifolia, Vitex peduncularis and Vitex altissima. The methanol extracts of the four species possessed varying levels of larvicidal nature. The highest larvicidal activity was found with the extract of V. trifolia (LC₅₀ = 41.41 ppm) followed by V. peduncularis (LC₅₀ = 76.28 ppm), V. altissima (LC₅₀ = 128.04 ppm) and V. negundo (LC₅₀ = 212.57 ppm).     

Anti-<Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> Antibodies are Frequent in Type 1 Diabetes

Anti-Saccharomyces cerevisiae antibodies (ASCA) have been described in many autoimmune diseases in which there is an increased intestinal permeability. Also in type 1 diabetes (T1D), there is an increased intestinal permeability. Since no data are available about ASCA in T1D, we evaluated, retrospectively, the frequency of ASCA in this disease. ASCA, IgG, and IgA, were determined by ELISA in sera of 224 T1D patients in which coeliac disease has been excluded and 157 healthy control group. The frequency of ASCA (IgG or IgA) was significantly higher in T1D patients than in the control group (24.5% vs. 2.5%, p < 10⁻⁷). The same observation was found in children and in adult patients when we compare them to healthy children and blood donors group respectively. Compared to children, adult patients with T1D showed significantly higher frequencies of ASCA of any isotype (38% vs. 13.7%, p < 10⁻⁴), both ASCA IgG and IgA (12% vs. 1.6%, p = 0.002), ASCA IgG (35% vs. 9.8%, p < 10⁻⁵) and ASCA IgA (15% vs. 5.6%, p = 0.001). The frequency of ASCA was statistically higher in females of all T1D than in males (30.8% vs.17.7%, p = 0.03), in girls than in boys (22% vs.6.2%, p = 0.017), and significantly higher in men than in boys (35.7% vs. 6.2%, p < 10⁻⁴). The frequency of ASCA IgG was significantly higher than that of ASCA IgA in all T1D patients (21% vs. 9.8%, p < 0.002), in all females (26.5% vs. 10.2%, p < 0.002), in women (37.9% vs. 12%, p < 0.001). The frequency of ASCA was significantly higher in all long-term T1D than in an inaugural T1D (29% vs. 14.5%, p = 0.019). The same observation was found in adults (45.8% vs. 17.8%, p = 0.01). In long-term T1D patients, ASCA were significantly more frequent in adults than children (45.8% vs. 14.5%, p < 10⁻⁴). The frequency of ASCA IgG was significantly higher in long-term T1D than in an inaugural T1D (25.2% vs. 11.6%, p = 0.03). Patients with T1D had a high frequency of ASCA.     

Clinical features and treatment outcomes of vancomycin-intermediate <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> (VISA) and heteroresistant vancomycin-intermediate <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> (hVISA) in a tertiary care institution in Singapore

This retrospective case–control study was undertaken to review the clinical features associated with heteroresistant vancomycin-intermediate Staphylococcus aureus (hVISA) and vancomycin-intermediate S. aureus (VISA) infections and the local impact they have on clinical outcome. Compared with vancomycin-susceptible S. aureus (n = 30), hVISA and VISA infections (n = 10) are found to be associated with a longer period of prior glycopeptide use (P = 0.01), bone/joint (P < 0.01) and prosthetic infections (P = 0.04), as well as treatment failure, as evidenced by longer bacteremic (P < 0.01) and culture positivity (P < 0.01) periods. This was observed to have resulted in longer hospital length of stay (P < 0.01) and total antibiotic therapy duration (P = 0.01). There was, however, no significant difference in the overall patient mortality or the hospitalization cost (P = 0.12) in both groups. Clinicians should be cognizant of the association between hVISA/VISA with high bacterial load deep-seated infections. We recommend targeted and even universal screening for hVISA/VISA in methicillin-resistant S. aureus (MRSA) infections.     

<Emphasis Type="Italic">Toxocara canis</Emphasis> larvae reinfecting BALB/c mice exhibit accelerated speed of migration to the host CNS

Using a small animal imaging system, migratory activity of Toxocara canis larvae stained by carboxyfluorescein succinimidyl ester (CFSE) was observed post primary infection (PPI) and post reinfection (PR) of BALB/c mice. Each infection was performed with 1,000 larvae per mouse. Primary infections were performed with labeled larvae, while for challenge infections the reinfecting larvae were stained by CFSE. The worm burden in mouse organs was determined during a period from 6 h to 21 days and 4 months PPI and PR. In comparison with primary infections that led to the first larvae appearance in the brain after 60 h, greatly accelerated migration of the parasites administered 3 weeks PPI to the CNS and eyes of challenged mice was noted—in both organs the larvae appeared 6 h PR. In all challenged mice, reinfecting larvae prevailed in the resident parasite population. Preliminary experiments with Toxocara cati larvae also revealed early brain involvement in primarily infected mice. Staining of T. canis larvae by CFSE had no effect on the development of a humoral antibody response against T. canis excretory–secretory antigens. In ELISA, elevated levels of specific IgG and IgG1 were noted on day 14 PPI and the levels of antibodies increased till the end of experiment. Reinfection induced an increase in the levels of both antibodies. In terms of optical density, IgG1 antibodies gave higher values in all sera examined. In ELISA for IgG antibodies, an increase in the avidity index of around 50% was detected 1 month PPI; higher-avidity antibodies were also detected in sera of reinfected animals.     

Comparison of the sensitivity of the <Emphasis Type="Italic">Legionella</Emphasis> urinary antigen EIA kits from Binax and Biotest with urine from patients with infections caused by less common serogroups and subgroups of <Emphasis Type="Italic">Legionella</Emphasis>

The detection of urinary antigen is the most widely used method to diagnose Legionnaires’ disease (LD), so it is important that these assays have a high sensitivity for the disease. In this study, we compare two kits for their ability to detect urinary antigen in urine samples from patients infected with Legionella species and L. pneumophila sero- and subgroups not considered as the most common causes of LD. Urine samples (n = 33) from 30 culture-proven cases of L. pneumophila serogroup (sg) 1, subgroup non-Pontiac infection, and urine samples (n = 35) from 32 cases of non-L. pneumophila species or non-sg 1 infection were examined using the Binax EIA and Biotest EIA kits. For both groups, the overall diagnostic sensitivity of the Binax kit was significantly better than the sensitivity of the Biotest kits (P < 0.0001). For the non-Pontiac group, the sensitivity was 81.8 and 42.4%, respectively, and for the non-sg1 group, it was 51.4 and 28.6%, respectively. It was concluded that the Binax kit was more suitable for the general diagnosis of LD than the Biotest kit, but we still need urinary antigen detection methods with higher sensitivity for non-sg1 LD.     

Evaluation of larvicidal and nymphicidal potential of plant extracts against <Emphasis Type="Italic">Anopheles subpictus</Emphasis> Grassi, <Emphasis Type="Italic">Culex tritaeniorhynchus</Emphasis> Giles and <Emphasis Type="Italic">Aphis gossypii</Emphasis> Glover

The acetone, chloroform, ethyl acetate, hexane and methanol extracts of peel and leaf extracts of Citrus sinensis, Ocimum canum, Ocimum sanctum and Rhinacanthus nasutus were tested against fourth instar larvae of malaria vector, Anopheles subpictus Grassi, Japanese encephalitis vector, Culex tritaeniorhynchus Giles (Diptera: Culicidae) and feeding deterrence to nymphs of cotton pest, Aphis gossypii Glover (Homoptera: Aphididae). The larval and nymph mortality were observed after 24 h of exposure. All extracts showed moderate larvicidal and nymphicidal effects; however, the highest mortality was found in peel chloroform extract of C. sinensis, leaf ethyl acetate extracts of O. canum and O. sanctum and leaf chloroform extract of R. nasutus against the larvae of A. subpictus (LC₅₀ = 58.25, 88.15, 21.67 and 40.46 ppm; LC₉₀ = 298.31, 528.70, 98.34 and 267.20 ppm), peel methanol extract of C. sinensis, leaf methanol extract of O. canum, ethyl acetate extracts of O. sanctum and R. nasutus against the larvae of C. tritaeniorhynchus (LC₅₀ = 38.15, 72.40, 109.12 and 39.32 ppm; LC₉₀ = 184.67, 268.93, 646.62 and 176.39 ppm), peel hexane extract of C. sinensis, leaf methanol extracts of O. canum and R. nasutus and leaf ethyl acetate extract of O. sanctum against the nymph of A. gossypii (LC₅₀ = 162.89, 80.99, 73.27 and 130.19 ppm; LC₉₀ = 595.40, 293.33, 338.74 and 450.90 ppm), respectively. These results suggest that the peel methanol extracts of C. sinensis and O. canum, ethyl acetate leaf extract of O. sanctum and leaf chloroform and ethyl acetate extract of R. nasutus have the potential to be used as an ideal eco-friendly approach for the control of the A. subpictus, C. tritaeniorhynchus and A. gossypii.     

Fate of <Emphasis Type="Italic">Cryptosporidium parvum</Emphasis> and <Emphasis Type="Italic">Cryptosporidium hominis</Emphasis> oocysts and <Emphasis Type="Italic">Giardia duodenalis</Emphasis> cysts during secondary wastewater treatments

This study investigates the fate of Cryptosporidium parvum and C. hominis oocysts and Giardia duodenalis cysts at four Irish municipal wastewater treatment plants (i.e., Plant A, B, C, and D) that utilize sludge activation or biofilm-coated percolating filter systems for secondary wastewater treatment. The fate of these pathogens through the sewage treatment processes was determined based on their viable transmissive stages, i.e., oocysts for Cryptosporidium and cysts for Giardia. Analysis of final effluent indicated that over 97% of viable oocysts and cysts were eliminated, except at Plant C, which achieved only 64% of oocyst removal. A significant correlation between the removal of oocysts and cysts was found at Plants A, B, and D (R = 0.98, P < 0.05). All sewage sludge samples were positive for C. parvum and C. hominis, and G. duodenalis, with maximum concentrations of 20 oocysts and eight cysts per gram in primary sludge indicating the need for further sludge sanitization treatments. This study provides evidence that C. parvum and C. hominis oocysts and G. duodenalis cysts are present throughout the wastewater processes and in end-products, and can enter the aquatic environment with consequent negative implications for public health.     

Combination antibiotic susceptibility of biofilm-grown <Emphasis Type="Italic">Burkholderia cepacia</Emphasis> and <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> isolated from patients with pulmonary exacerbations of cystic fibrosis

We identified double and triple antibiotic combinations effective against biofilm-grown Burkholderia cepacia and Pseudomonas aeruginosa sampled from cystic fibrosis (CF) patients undergoing acute pulmonary exacerbations. Sputum bacteria from 110 CF patients were grown as biofilms. Combination antibiotic susceptibility testing was used to test 94 double and triple antibiotic combinations. Biofilm-grown bacterial isolates were less susceptible to antibiotic combinations compared to the same bacterial isolates grown planktonically (P < 0.001). Fifty-nine percent of biofilm-grown B. cepacia isolates and 29% of P. aeruginosa isolates were resistant to all double antibiotic combinations tested. Triple antibiotic combinations were more effective than double antibiotic combinations against biofilms (P < 0.0001). For P. aeruginosa biofilms, the addition of azithromycin or rifampin to otherwise effective antibiotic combinations was frequently associated with antagonism. Bacterial biofilms of CF organisms are highly resistant to antibiotics. This study identified potentially effective antibiotic combinations to guide the empirical treatment of CF pulmonary exacerbations.     

Age-influenced population kinetics and immunological responses of <Emphasis Type="Italic">Leishmania donovani</Emphasis> in hamsters

Susceptibility of animals to infections depends upon various factors including sex and age of the host, which plays a pivotal role. In this communication, we have investigated the “intake” of Leishmania donovani infection in young (3–4 weeks old) and adult (15–16 weeks old) golden hamsters. The splenic parasite load in young hamsters on day 15 post infection (p.i.) was 54 ± 4 amastigotes/100 macrophage nuclei and increased to 106.3 ± 3.5 on day 30 p.i. However, adult group showed 2.2-(P < 0.001) and 1.75-fold (P < 0.001) lesser parasite burden on these days, respectively. But as the disease progresses further, differences in parasite burden become less significant, as revealed by comparable levels of parasite loads at 2 months p.i. Spleen weight measurements correspond to the above observations. In the young group, the levels of antileishmanial antibody rise two and 4.5 times on days 15 and 30 p.i., respectively, as compared to only 1.3 and 2.3 times increase in their respective adult counterparts. However, after 2 months of infection both groups recorded analogous (12-fold) rise in antibody levels. Both mitogenic and antigenic responses in adult hamsters were less suppressed compared to young hamsters on days 15 and 30 p.i. However, both groups exhibited highly suppressed cell-mediated immune (CMI) responses after 2 months of infection. These findings implicate that age of the host may influence the susceptibility and resistance to Leishmania infection.     

Anthelmintic activity of <Emphasis Type="Italic">Spigelia anthelmia</Emphasis> extract against gastrointestinal nematodes of sheep

In vitro (larval development assay) and in vivo studies were conducted to determine possible direct anthelmintic effect of ethanolic and aqueous extracts of Spigelia anthelmia towards different ovine gastrointestinal nematodes. The effect of extracts on development and survival of infective larvae stage (L₃) was assessed. Best-fit LC₅₀ values were computed by global model of non-linear regression curve fitting (95% confidence interval). Therapeutic efficacy of the ethanolic extracts administered orally at a dose rate of 125, 250, and 500 mg/kg, relative to a non-medicated control group of sheep harbouring naturally acquired infection of gastrointestinal nematodes, was evaluated in vivo. The presence of S. anthelmia extracts in the cultures decreased the survival of L₃ larvae. The LC₅₀ of aqueous extract (0.714 mg/ml) differ significantly from the LC₅₀ of the ethanolic extract (0.628 mg/ml) against the strongyles (p < 0.05, paired t-test). Faecal egg counts on day 12 after treatment showed that the extract is effective, relative to control (one-way analysis of variance [ANOVA], Dunnett’s multiple comparison test) at 500 mg/kg against Strongyloides spp. (p < 0.01), 250 mg/kg against Oesophagostomum spp., Trichuris spp. (p < 0.05), and 125 mg/kg against Haemonchus spp. and Trichostrongylus spp. (p < 0.01). The effect of the doses is significant in all cases, the day after treatment is also extremely significant in most cases, whereas interaction between dose and day after treatment is significant (two-way ANOVA). S. anthelmia extract could, therefore, find application in the control of helminth in livestock, by the ethnoveterinary medicine approach.     

Characterization of <Emphasis Type="Italic">Taenia solium</Emphasis> cysticerci microsomal glutathione <Emphasis Type="Italic">S</Emphasis>-transferase activity

Glutathione S-transferase activity has been shown to be associated with the microsomal fraction of Taenia solium. Electron microscopy and subcellular enzyme markers indicate the purity of the microsomal fraction that contains the glutathione S-transferase activity. T. solium microsomes were solubilized under conditions used to solubilize integral microsomal proteins. This procedure proved necessary to obtain enzymatic activity. To characterize this parasite enzyme activity, several substrates and inhibitors were used. The optimum activity for microsomal glutathione S-transferase was found to be pH 6.6, with a specific enzyme activity of 0.9, 0.1, 0.067, 0.03, and 0.05 μmol min⁻¹ mg⁻¹ with the substrates 1-chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4-nitrobenzene, 4-hydroxynonenal, 2,4-hexadienal, and trans-2-nonenal, respectively. No activity of glutathione peroxidase was observed. T. solium microsomes had an _app K _{m (GSH)} = 0.161 μM, _app K _{m (CDNB)} = 14.5 μM, and _app V _max of 0.15 and 27.9 μmol min⁻¹ mg⁻¹ for GSH and CDNB, respectively. T. solium microsomes were inhibited by several glutathione S-transferase enzyme inhibitors, and it was possible to establish a simple inhibition system as well as corresponding K _i ’s for each inhibitor. These results indicate that the T. solium microsomal glutathione S-transferase is different from the parasite cytoplasmic enzymes that catalyze similar reactions.