Comparative in vitro activity of carbapenems against clinical isolates of Acinetobacter baumannii.

AIMS: The aim of this multi-hospital study was to assess the in vitro activity of doripenem and its comparators, imipenem and meropenem, using the new CLSI breakpoints against a large population of a frequently isolated nosocomial pathogen, Acinetobacter baumannii. METHODS AND RESULTS: During a 2-year period, four referral or tertiary hospitals submitted 400 isolates of Ac. baumannii for susceptibility testing using imipenem, meropenem and doripenem via disc diffusion and E-test methods. A subset of 390 isolates was resistant to all three tested carbapenems. Doripenem and meropenem (MIC50 , 32 µg ml(-1) ) had comparable activity, albeit doripenem's activity was greater than imipenem (MIC50 , >32 µg ml(-1) ). A significantly higher proportion of the isolates were inhibited by doripenem than by imipenem at MIC values of 12, 16, 24 and 32 µg ml(-1) (P < 0·05). The cumulative percentage of imipenem MICs was lower compared to its comparators. The comparison of resistance rate to imipenem and meropenem based on old and new breakpoints showed <1% difference. The overall agreement between the two susceptibility testing methods was ≥95%. CONCLUSION: Doripenem has a slightly greater in vitro activity than imipenem in terms of zone breakpoints and MIC values, but its activity is comparable to meropenem. SIGNIFICANCE AND IMPACT OF THE STUDY: Doripenem should be considered as a therapeutic option for monotherapy or combination therapy, particularly when the therapeutic options are limited.

Tumour Necrosis Factor-alpha (TNF-α) and its soluble receptor type 1 (sTNFR I) in human active and healed leishmaniases.

The role of tumour necrosis factor-alpha (TNF-α) is not fully understood in human leishmaniasis. We analysed the alterations in the levels of TNF-α, soluble TNF receptor type 1 (sTNFR I), IL-17 and IL-22 productions in active and healed leishmaniases. Blood samples were collected from volunteers with active cutaneous leishmaniasis (ACL), the same subjects after lesion healing (healed CL = HCL), volunteers with active visceral leishmaniasis (AVL), healed VL (HVL) and healthy controls. Levels of cytokines were titrated on Leishmania Ag-stimulated PBMC culture. The mean level of TNF-α production from stimulated cells was significantly higher in ACL than controls (P < 0·001) and significantly reduced after treatment in HCL volunteers (P < 0·05). The mean level of sTNFR I production was significantly higher in ACL than controls (P < 0·001) and significantly reduced after treatment in HCL volunteers (P < 0·05). The mean level of IL-22 production in AVL was significantly higher than controls (P < 0·05) and was significantly lower in HVL compared with AVL (P < 0·001) and controls (P < 0·05). The levels of TNF-α (P = 0·0025) and sTNFR I (P < 0·01) productions from PBMCs showed significant decreasing trend after treatment in each CL volunteer. Reduction in TNF-α is associated with clinical response to treatment and healing of CL lesions due to L. major.

Plasma levels of tumor necrosis factor-alpha (TNF-α), TNF-α soluble receptor type 1 (sTNFR I) and IL-22 in human leishmaniasis.

The role of pro-inammatory cytokine tumor necrosis factor-alpha (TNF-α) in human leishmaniasis is not fully understood. We analyzed the alterations in the plasma levels of TNF- α, soluble TNF receptor type 1 (sTNFR I), IL-17 and IL-22 in the volunteers with leishmaniasis. Blood samples were collected from patients with active cutaneous leishmaniasis (CL), the same CL patients after standard antimonial therapy as healed CL, active visceral leishmaniasis (VL) and healed VL volunteers. Levels of the cytokines were titrated on plasma samples by sandwich ELISA method. The mean level of TNF-α was significantly higher in active CL patients than healthy controls (P<0.001) and significantly reduced after treatment in the same volunteers (P<0.001). The mean level of sTNFR I was significantly higher in active CL patients than healthy controls (P<0.05). The mean level of IL-22 in plasma of the AVL patients was significantly higher than that of healthy control group (P<0.05). There is a negative correlation between the levels of TNF-α and sTNFR I and healing of CL. Measurement of cytokines in plasma samples is more feasible than cell culture in evaluation of immune response in human leishmaniasis.

Plasma levels of tumor necrosis factor-alpha (TNF-α), TNF-α soluble receptor type 1 (sTNFR I) and IL-22 in human leishmaniasis

The role of pro-inammatory cytokine tumor necrosis factor-alpha (TNF-α) in human leishmaniasis is not fully understood. We analyzed the alterations in the plasma levels of TNF- α, soluble TNF receptor type 1 (sTNFR I), IL-17 and IL-22 in the volunteers with leishmaniasis. Blood samples were collected from patients with active cutaneous leishmaniasis (CL), the same CL patients after standard antimonial therapy as healed CL, active visceral leishmaniasis (VL) and healed VL volunteers. Levels of the cytokines were titrated on plasma samples by sandwich ELISA method. The mean level of TNF-α was significantly higher in active CL patients than healthy controls (P<0.001) and significantly reduced after treatment in the same volunteers (P<0.001). The mean level of sTNFR I was significantly higher in active CL patients than healthy controls (P<0.05). The mean level of IL-22 in plasma of the AVL patients was significantly higher than that of healthy control group (P<0.05). There is a negative correlation between the levels of TNF-α and sTNFR I and healing of CL. Measurement of cytokines in plasma samples is more feasible than cell culture in evaluation of immune response in human leishmaniasis.

Isospora belli associated recurrent diarrhea in a child with AIDS.

Persistent diarrhea is a major manifestation of Acquired Immunodeficiency Syndrome (AIDS) which might be more complicated in Human Immunodeficiency Virus (HIV) infected children especially those from developing countries. There are numerous reports showing the emergence of intestinal opportunistic coccidian parasites, mostly Cryptosporidium parvum and Isospora belli in HIV-infected individuals. The prevalence of isosporiasis is probably underestimated in developing countries because routinely not all HIV-infected patients are examined for the presence of this protozoan infection. Here we report a case of HIV-infected isosporiasis presenting with failure to thrive and persistent diarrhea. Since I. belli infection in children responds well to therapy with trimethoprim-sulfamethoxazole, isosporiasis should be considered as a treatable infection in AIDS, if it is detected at proper time.

Immune response of BALB/c mice against an experimental vaccine of Alum precipitated autoclaved Leishmania major (Alum-ALM) mixed with BCG or Mycobacterium vaccae.

Immune response in BALB/c mice immunized 3 times with different doses (50 µg or 200 µg of protein) of Alum precipitated autoclaved Leishmania major (Alum-ALM) mixed with either BCG (1x10(7); CFU) or different doses of killed Mycobacterium vaccae (1x10(6), 1x10(7)) was assessed. Mice immunized with low dose of Alum-ALM mixed with either BCG or low M. vaccae showed a significantly higher IFN-gamma production and a lower IL-4 level and a significantly lower parasite burden compared to the control PBS injected group. It seems that immunization with a low dose of Alum-ALM mixed with an adjuvant induces a Th1 type of immune response in susceptible BALB/c mice.

Differential in vitro CD4+/CD8+ T-cell response to live vs. killed Leishmania major.

Clinical trials of killed Leishmania vaccines showed a limited efficacy compared with leishmanization (LZ). The reason for this difference in protection against cutaneous leishmaniasis (CL) is not known and in vivo studies on T-cell function may provide valuable information. Nevertheless, there are limited studies on the nature of the stimulatory effects of live vs. killed parasites on human T cells in vitro. A total of nine Leishmanin Skin Test+ volunteers with a history of self-healing CL (HCL) and seven healthy volunteers were included in this study. 5,6-carboxyfluroescein diacetate succinimidyl ester-labelled CD4(+)/CD8(+) lymphocytes were cultured with killed Leishmania Lysate (Killed LL) or live Leishmania major (Live LM) and analysed for proliferation using flow cytometry. Culture supernatants were used for cytokine titration. In HCL volunteers, upon stimulation with killed LL, the number of proliferated CD4(+)/CD8(+) cells was significantly more than that of unstimulated (P < 0.001) or live LM stimulated (P < 0.05) cells, or cells from controls (CD4(+)/CD8(+): P < 0.05/P < 0.001). Stimulation of CD4(+) cells with Live LM (P < 0.001) or Killed LL (P < 0.05) induced a significantly higher IFN-gamma production compared with that of controls, but Live LM induced significantly (P < 0.05) more IFN-gamma than Killed LL. A significantly (P < 0.05) higher IFN-gamma production was observed when CD8(+) cells were stimulated with Live LM. Cells from HCL volunteers showed significantly more IL-10 production to Live LM stimulation compared with that of controls (CD4(+): P < 0.05 /CD8(+): P < 0.001) or cells stimulated with Killed LL (CD4(+)/CD8(+): P < 0.001/P < 0.0005). Whereas Killed LL induced more proliferation response in purified T cells, Live LM induced cytokine production without significant induction of proliferation. The results from healed CL volunteers in this study could be implicated in further studies on T-cell response in vaccinated individuals.

Immune response of BALB/c mice against an experimental vaccine of Alum precipitated autoclaved Leishmania major (Alum-ALM) mixed with BCG or Mycobacterium vaccae

Immune response in BALB/c mice immunized 3 times with different doses (50 mug or 200 mug of protein) of Alum precipitated autoclaved Leishmania major (Alum-ALM) mixed with either BCG (1 x10(7); CFU) or different doses of killed Mycobacterium vaccae (1 x10(6), 1 x10(7)) was assessed. Mice immunized with low dose of Alum-ALM mixed with either BCG or low M. vaccae showed a significantly higher IFN-gamma production and a lower IL-4 level and a significantly lower parasite burden compared to the control PBS injected group. It seems that immunization with a low dose of Alum-ALM mixed with an adjuvant induces a Th1 type of immune response in susceptible BALB/c mice.