Introduction: Among the bacterial causes, diarrheagenic Escherichia coli (DEC) is the most important etiologic agent of childhood diarrhoea and represents a major public health problem in developing countries. New evidence suggests that major differences in virulence among groups of DEC pathotypes may be related to the presence of specific pathogenicity islands (PAIs). Methodology: Multiplex and conventional PCR assays were used to identify the DEC pathotypes and PAIs respectively from 207 E. coli isolates. Results: The predominant DEC pathotype isolated was EPEC 19.3% (40/207), followed by ETEC 7.25% (15/207), EAEC 3.86% (8/207), STEC 0.97% (2/207) and EIEC 0.48% (1/207). The PAIs detected were enteropathogenic secreted protein C (EspC) 12.2% (8/66), locus of enterocyte effacement (LEE) 62.1% (41/66), and high pathogenicity island (HPI) 57.6% (38/66). Six percent (4/66) expressed only fyuA gene, 12.2% (8/66) irp2 only, and 39.4% (26/66) expressed both fyuA and irp2 genes. SHI-2 39.4% (26/66), she 6% (4/66) and O island 33.3% (22/66), 19.8% (13/66) expressed only efa/lifA gene, 7.6% (5/66) pagC gene only and 6.1% (4/66) expressed both efa/lifA and pagC genes. Toxigenic invasion A (TIA) PAI was not detected. Conclusion: This study revealed that in addition to eaeA, stx, aat, einv, st and lt virulence genes exhibited in the different DEC pathotypes there are numerous PAIs in the DEC pathotypes. The PAIs can increase gene mobility within various motile elements, which has implications for the spread of virulence factors from DEC to commensal E. coli.

f Bacterial adherence determines the virulence of many human-pathogenic bacteria. Experimental approaches elucidating this early infection event in greater detail have been performed using mainly methods of cellular microbiology. However, in vitro infections of cell monolayers reflect the in vivo situation only partially, and animal infection models are not available for many human-pathogenic bacteria. Therefore, ex vivo infection of human organs might represent an attractive method to overcome these limitations. We infected whole human umbilical cords ex vivo with Bartonella henselae or Acinetobacter baumannii under dynamic flow conditions mimicking the in vivo infection situation of human endothelium. For this purpose, methods for quantifying endotheliumadherent wild-type and trimeric autotransporter adhesin (TAA)-deficient bacteria were set up. Data revealed that (i) A. baumannii binds in a TAA-dependent manner to endothelial cells, (ii) this organ infection model led to highly reproducible adherence rates, and furthermore, (iii) this model allowed to dissect the biological function of TAAs in the natural course of human infections. These findings indicate that infection models using ex vivo human tissue samples ("organ microbiology") might be a valuable tool in analyzing bacterial pathogenicity with the capacity to replace animal infection models at least partially.T he analysis of adhesion to host cells is crucial for the elucidation of bacterial infection mechanisms. Animal infection models or cellular microbiology-based approaches are well established, and many important findings have thereby been gathered. By way of example, the protein injection machineries and the autotransporter adhesins (TAA) of Bartonella henselae and Acinetobacter baumannii have been elucidated in that manner (1-3). Although these methods are well established and widely accepted, they still are hampered by several limitations: animal models might reflect the course of human infections only partially (4) or might not even be available for many pathogens (e.g., B. henselae). Cellular infection models allow very detailed analyses of the interaction of bacteria with host cells under standardized conditions. However, they are usually done statically using cell monolayers, and this mimics the complexity of in vivo infection situation only to some extent. Methods to overcome the species barrier in infection models and to analyze host-pathogen interactions close to the dynamic human situation are urgently needed. Ex vivo infection models, using human organ grafts, might represent an attractive alternative or addition to animal or cellular microbiology experiments.B. henselae causes cat scratch disease and endocarditis, whereas immunosuppressed individuals can suffer from vasculoproliferative disorders such as bacillary angiomatosis. B. henselae is believed to be an endotheliotropic pathogen. Bartonella adhesin A (BadA) has been identified as the key factor involved in the adherence to endothelial cells (ECs) and to extracellular matrix (EC...

Background: Extended spectrum beta lactamases (ESBLs) producing Enterobacteriaceae cause infections that are often reported in both hospital and community setting. These infections are on the increase and jeopardize the achievement of modern medicine because of their clinical implications. There is need for surveillance measures to be taken, both by the health care personnel and the community at large. Methodology: We examined 330 diarrhea stool samples from children below the age of 5 years and processed them. A total of 96 (29%) samples were identified as Klebsiella pneumoniae out of the bacteria isolated. Identification of ESBL was done and 42 K. pneumoniae isolates were tested for the occurrence of bla CTX-M, bla OXA, bl aTEM and bla SHV resistant genes by PCR, gel electrophoresis and visualized by UV illumination. Results: Our results revealed that bla CTXM was the most frequent ESBL type 42 (100%), followed by bla TEM in 41 (97.6%) isolates and bla SHVin38 (90.4%) of the isolates. None of the tested isolates were found to be encoding bla OXA. There was occurrence of more than one gene in most of the isolates. The double combination was detected in bla CTX-M/ bla TEM (9.5%) and bla CTXM/SHV (2.4%). A triple combination was noted bla-TEM/ bla SHV/ bla CTX-M (88%). Conclusion: Our results indicate that there is Presence of Beta lactam genes associated with antimicrobial resistance among the K. pneumoniae isolates from Mukuru Slum, Kenya. The predominant ESBL genotype in Mukuru slums, Kenya was bla CTX-M followed by bla TEM and bla SHV respectively. There is need for surveillance measures to be taken so as to control the spread among the community.

Antimicrobial resistance (AMR) is a global threat to public health and particularly to children. This study aimed to determine the prevalence of multidrug resistance of fecal Klebsiella spp on selected beta lactam (3 rd generation cephalosporins and carbapenems) and fluoroquinolone classes of drugs in four health facilities serving the slum communities of Nairobi city in Kenya. Additionally, determine the genetic basis for the multidrug resistance observed. A cross sectional laboratory based study was undertaken where a total of 1171 children below 16 years were selected, from whom stool samples were collected, tested and analyzed. 395 (33.73%) Klebsiella spp were isolated, consisting of 365 (92.4%) Klebsiella pneumoniae and 30 (7.6%) Klebsiella oxytoca were isolated. The proportion of multi-drug resistance (MDR) K. pneumoniae and MDR K. oxytoca was 64.1% (234/365) and 96.67% (29/30) respectively. Third generation cephalosporins, cefotaxime ceftriaxone and ceftazidime showed the highest resistance of 30.7%, 29.9% and 27.4% respectively, whereas carbapenems including imipenem and meropenem had the least resistance of 1.6%, each, to K. pneumoniae. A significant association was observed in diarrheic children (OR = 1.88; p = 0.01) and those below 50 months (OR = 0.43; p = 0.002) and carrying K. pneumoniae resistance to one or more third generation cephalosporins. Genes associated with resistance included bla TEM 100%, bla CTX-M 95.2%, bla SHV 57.1%, bla OXA-1 66.7%,

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