Cryptosporidium species in HIV patients in Alexandria, Egypt: distribution and associated clinical findings

@#Cryptosporidium sp. cause opportunistic infections in HIV patients. Molecular differentiation provides a better understanding of the epidemiology and clinical variations of cryptosporidiosis. The present work studied the species of Cryptosporidium in HIV patients and their associated demographic and clinical features. The study included 100 adult HIV patients receiving antiretroviral therapy in Egypt. Cryptosporidium infection was diagnosed by modified ZiehlNeelsen (MZN) stain and PCR amplification of COWP gene. The infecting species were molecularly identified by restriction fragment length polymorphism (RFLP) and DNA sequencing. Data were analyzed using Kappa (K) agreement, Mann–Whitney U, odds ratio and the 95% confidence interval, Chi-squared and Monte Carlo significance (MCp) tests. The statistical significance was judged at the 5% level. A total of 16 Cryptosporidium positive cases were detected (16%), with good agreement between PCR and MZN (K = 0.763). Among 11 PCR positive samples, RFLP identified C. hominis in five samples, C. parvum in three samples, C. meleagridis in two samples, and mixed C. hominis and C. meleagridis in one sample. Eight samples were successfully sequenced and the results confirmed the RFLP classification. C. hominis was found mainly in urban residents while C. parvum and C. meleagridis were significantly associated with rural areas (MCp =0.01). Diarrhoea and nausea/vomiting were recorded only in the presence of C. hominis infection while abdominal pain was the main symptom in C. parvum and C. meleagridis infections. Drinking water sources, contact with animals, and CD4+ count were not related to infection with a particular species. In conclusion, infection with Cryptosporidium sp. is common and frequently symptomatic in HIV patients in Egypt. The predominant species, C. hominis, C. parvum, and C. meleagridis show a distinct distribution in urban and rural residents.

Intestinal protozoan infections among Egyptian neutropenic patients with acute leukemia

@#Several enteric protozoan species are linked to diarrhea in humans, with some causing debilitating illnesses, essentially in immunocompromised and neutropenic patients as in acute leukemias. The aim of this study was to detect intestinal protozoa in Egyptian neutropenic patients with acute leukemia. The study comprised two groups; 40 newly diagnosed neutropenic acute leukemia patients and 30 controls. Stool samples were collected from all participants and subjected to routine microscopic examination, special staining and detection of copro-antigen using rapid diagnostic test (RDT) RIDA®QUICK Entamoeba/ Giardia/ Cryptosporidium Combi. Cases were tested post-chemotherapy at the nadir of neutropenia (absolute neutrophil count ANC< 0.5x109/L) and 19 cases were also tested initially prior to chemotherapy. Of examined patients, 15/40 (37%) were positive for Blastocystis hominis by wet mount, 10/40 (25%) had microsporidia using modified trichrome stain and only 2 cases (5%) of Cryptosporidium spp. by Ziehl-Neelsen stain. By RDT, 8/40 cases (20%) were positive compared to entirely negative controls. The positive cases included 4 patients with G. intestinalis 2 with Entamoeba and 2 with Cryptosporidium.19/40 cases were tested both pre- and post-chemotherapy. microsporidian spp. was diagnosed in 6/19 cases at the nadir of neutropenia compared to none of the cases pre-chemotherapy and the difference was statistically significant (p= 0.031*). Intestinal protozoa in acute leukemia patients post-chemotherapy are common especially B. hominis. Furthermore, RDT might be helpful for diagnosing intestinal protozoa in acute leukemia. Attention is highly required as intestinal protozoa infection can emerge after chemotherapy such as microsporidia.

Enzymatic and biochemical characterization of Bungarus sindanus snake venom acetylcholinesterase

This study analyses venom from the elapid krait snake Bungarus sindanus, which contains a high level of acetylcholinesterase (AChE) activity. The enzyme showed optimum activity at alkaline pH (8.5) and 45ºC. Krait venom AChE was inhibited by substrate. Inhibition was significantly reduced by using a high ionic strength buffer; low ionic strength buffer (10 mM PO4 pH 7.5) inhibited the enzyme by 1. 5mM AcSCh, while high ionic strength buffer (62 mM PO4 pH 7.5) inhibited it by 1 mM AcSCh. Venom acetylcholinesterase was also found to be thermally stable at 45ºC; it only lost 5% of its activity after incubation at 45ºC for 40 minutes. The Michaelis-Menten constant (Km) for acetylthiocholine iodide hydrolysis was found to be 0.068 mM. Krait venom acetylcholinesterase was also inhibited by ZnCl2, CdCl2, and HgCl2 in a concentrationdependent manner. Due to the elevated levels of AChE with high catalytic activity and because it is more stable than any other sources, Bungarus sindanus venom is highly valuable for biochemical studies of this enzyme.(AU)