Shigella and Salmonella strains isolated from children under 5 years in Gaborone, Botswana, and their antibiotic susceptibility patterns. (25/669)

We isolated Shigella from 43/221 (21%) and Salmonella 8/221 (3%) rectal swabs from children under 5 years with diarrhoea, and found Shigella in two of 100 specimens from children without diarrhoea. Sh. boydii (13%) was the most prevalent Shigella species followed by Sh. flexneri (6%) and Sh. sonnei (2%). The prevalence of various types of Sh. boydii was type 7, 5%; type 9, 3%; type 12 and 16, 2%; and type 18, 1%. Other Shigella serotypes encountered were Sh. flexneri type 6 (4%), type 4 (2%), with Sh. sonnei phase II isolated from 2% of the specimens. The Salmonella species were S. typhimurium and S. paratyphi. The high rate of isolation of Shigella species from children with diarrhoea is indicative of a definite role of this enteropathogen in causing endemic diarrhoea in Gaborone, Botswana. Antibiograms of the predominant isolates showed that most Shigella species were resistant to ampicillin but susceptible to chloramphenicol, and with the exception of Sh. flexneri type 6, also susceptible to gentamicin. The Salmonella species were susceptible to chloramphenicol, collistin-sulphate, gentamicin, cotrimoxazole, and ampicillin.  (+info)

Multicenter evaluation of resistance patterns of Klebsiella pneumoniae, Escherichia coli, Salmonella spp and Shigella spp isolated from clinical specimens in Brazil: RESISTNET Surveillance Program. (26/669)

Surveillance programs are essential to detect the increase of antimicrobial resistance, and several different programs are being conducted in many countries. The RESISTNET is a surveillance program for bacterial resistance against several antimicrobial agents initiated in 1998 among Latin American countries. In Brazil, several centers were invited to join this surveillance and a total of 11 centers (6 from Sao Paulo and 5 from other states) participated in the study. All results were analyzed using the WHONET program. A total of 894 Escherichia coli, 386 Klebsiella pneumoniae, 70 Shigella spp and 57 Salmonella spp strains were analyzed in this study from April, 1998, to April, 1999. Susceptibility testing was performed by the disk diffusion method using NCCLS 1998 guidelines for several different drugs. For all strains, imipenem was the most effective drug (100% of the strains were susceptible). Klebsiella pneumoniae presented a high resistance rate to ampicillin (96.4%). The rate of probable ESBL producers among K. pneumoniae strains was 36.3%, most of them being isolated from catheters (58.8%). Among all Escherichia coli strains analyzed, the highest resistance rate was found for trimethoprim/sulfamethoxazole (46.9%) and the majority of the resistant strains were isolated from urine samples (47.8%). Among Salmonella spp, the resistance rates were low for all antibiotics tested. For Shigella spp strains there was a high resistance to trimethoprim/sulfamethoxazole (80.0%). No resistance to ceftriaxone was observed in these strains. Surveillance of antimicrobial resistance is critical for the successful management of infectious diseases. The results of this survey show significant resistance rates among these bacteria which are responsible for several types of human infections.  (+info)

Serum factors capable of opsonizing Shigella for phagocytosis by polymorphonuclear neutrophils. (27/669)

Twenty-five Shigella strains were tested for their susceptibility to phagocytosis and killing by polymorphonuclear neutrophils (PMN). The studies identified several serum factors that could participate in opsonization. The strains varied remarkably in their susceptibility to killing when heat-stable opsonins were employed, but all strains were killed when exposed to heat-labile opsonins and PMN. The heat-stable opsonin was shown to be IgG, whereas IgM was ineffective in the absence of complement, and 11S IgA was never effective. Heat labile opsonization required immunoglobulin as well as complement, but IgM was the only immunoglobulin demonstrated to participate in this reaction. The alternative C3 activating pathway is required for efficient heat-labile opsonization of Shigella, but some opsonization also appeared to occur through the C1-C4-C2 pathway of C3 activation.  (+info)

Antimicrobial-resistant bacterial diarrhea in rural western Kenya. (28/669)

Bacterial diarrheal diseases cause substantial morbidity and mortality in sub-Saharan Africa, but data on the epidemiology and antimicrobial susceptibility patterns of enteric bacterial pathogens are limited. Between May 1997 and April 1998, a clinic-based surveillance for diarrheal disease was conducted in Asembo, a rural area in western Kenya. In total, 729 diarrheal specimens were collected, and 244 (33%) yielded >or=1 bacterial pathogen, as determined by standard culture techniques; 107 (44%) Shigella isolates, 73 (30%) Campylobacter isolates, 45 (18%) Vibrio cholerae O1 isolates, and 33 (14%) Salmonella isolates were identified. Shigella dysenteriae type 1 accounted for 22 (21%) of the Shigella isolates. Among 112 patients empirically treated with an antimicrobial agent and whose stool specimens yielded isolates on which resistance testing was done, 57 (51%) had isolates that were not susceptible to their antimicrobial treatment. Empiric treatment strategies for diarrheal disease in western Kenya need to be reevaluated, to improve clinical care.  (+info)

Shigella protein IpaH(9.8) is secreted from bacteria within mammalian cells and transported to the nucleus. (29/669)

Various pathogenic bacteria such as Shigella deliver effector proteins into mammalian cells via the type III secretion system. The delivered Shigella effectors have been shown to variously affect host functions required for efficient bacterial internalization into the cells. In the present study, we investigated the IpaH proteins for their ability to be secreted via the type III secretion system and their fate in mammalian cells. Upon incubation in a medium containing Congo red, the bacteria secrete IpaH into the medium, but secretion of IpaH occurs later than that of IpaBCD. Immunofluorescence microscopy indicated that IpaH(9.8) is secreted from intracellular bacteria and transported into the nucleus. On microinjection of the protein, intracellular IpaH(9.8) is accumulated at one place around the nucleus and transported into the nucleus. This movement seems to be dependent on the microtubule network, since nuclear accumulation of IpaH(9.8) is inhibited in cells treated with microtubule-destabilizing agents. In nuclear import assay, IpaH(9.8) was efficiently transported into the nucleus, which was completely blocked by treatment with wheat germ agglutinin. The nuclear transport of IpaH(9.8) does not depend on host cytosolic factors but is partially dependent on ATP/GTP, suggesting that, like beta-catenin, IpaH(9.8) secreted from intracellular Shigella can be transported into the nucleus.  (+info)

Antimicrobial agent resistance in bacterial isolates from patients with diarrhea and urinary tract infection in the Sudan. (30/669)

Antimicrobial sensitivity tests were performed on four-hundred and ninety-seven bacterial isolates from Sudanese patients with diarrhea or urinary tract infections. Shigella dysenteriae type I and enteropathogenic Escherichia coli showed high resistance rates (percentage of isolates showing antibiotic resistance) against the commonly-used antimicrobial agents: ampicillin, amoxicillin, chloramphenicol, tetracycline, cotrimoxazole, nalidixic acid, sulfonamide, and neomycin, and were completely sensitive to ciprofloxacin. Eighteen resistance patterns against nine antimicrobial agents tested were observed in enteric pathogens. Resistance to ampicillin, amoxicillin, tetracycline, cotrimoxazole, and sulfonamide was the most frequent pattern. The common urinary pathogens, E. coli, Klebsiella pneumoniae, and Proteus mirabilis showed high rates of resistance to ampicillin, amoxicillin, cotrimoxazole, tetracycline, sulfonamide, trimethoprim, streptomycin, and carbenicillin. We recommend that physicians seek updated knowledge of the common antibiotic-sensitivity patterns when starting empirical antibiotic therapy in Sudanese patients with diarrhea or urinary tract infection.  (+info)

A comparison of the isolation rates of Salmonella and thermophilic Campylobacter species after direct inoculation of media with a dilute faecal suspension and undiluted faecal material. (31/669)

Regardless of media used, dilution of faecal samples before direct plating may improve isolation rates and reduce subcultures by freeing organisms from the faecal mass and diminishing competing flora. Despite the routine use of dilution in many laboratories, it has never been established properly whether direct or dilute inocula should be used in primary plating of faeces. A total of 3764 faecal samples was examined in four laboratories with a standardised methodology. The isolation rates, competing flora and confirmatory work performed for Salmonella spp. and Campylobacter spp. from primary plating media with a dilute faecal inoculum were compared with those after direct inoculation of faecal material. Inoculum effects on the isolation of Shigella spp. could not be assessed as only one isolate occurred during the study period. The overall isolation rates of both major enteric pathogens were unaffected by the inoculum. However, significantly fewer wasted subcultures were recorded with a dilute inoculum for Campylobacter spp., and competing florawas reduced in all cases without diluting out small numbers of the pathogen.  (+info)

Sensitivity and performance characteristics of a direct PCR with stool samples in comparison to conventional techniques for diagnosis of Shigella and enteroinvasive Escherichia coli infection in children with acute diarrhoea in Calcutta, India. (32/669)

As the sensitivity of the conventional techniques for identifying Shigella spp. and enteroinvasive Escherichia coli (EIEC) causing dysentery cases is low, a PCR assay was evaluated in this study. Analytical sensitivity (2 x 10(2) cfu) of the PCR technique was obtained by artificially spiking negative stool samples with a standard strain of S. flexneri type 2, then determining the detection limit. Specificity (100%) of the method was determined by testing a number of known Shigella and EIEC strains and organisms other than Shigella spp. A total of 300 stool samples collected from children with acute diarrhoea was plated on to two selective agar media after enrichment in Luria broth. Shigella spp. were isolated from 7.7% (23 of 300) and EIEC from 1% (3 of 300) patients. All enriched stool samples were subjected to PCR to amplify the target sequence of invasive plasmid antigen (ipa)H locus, a multicopy element found on the chromosome and invasion plasmid. The stool PCR was positive in 24 of the 26 culture-positive and in 22 culture-negative stools, thus detecting the presence of Shigella spp. or EIEC in 15.3% (46 of 300) of diarrhoea cases. When an ial probe was used for colony hybridistion with enriched stool cultures blotted on to membranes, 9.6% (29 of 300) of dysentery cases were identified as being caused by Shigella spp. or EIEC. Thus the sensitivity of enriched stool culture, colony hybridisation and enriched stool PCR was found to be 54%, 60% and 96%, respectively, when each of the methods was compared to the total microbiologically confirmed cases of dysentery. It was also observed that only 38% (48 of 126) of acute bloody dysentery cases actually had shigella or EIEC infection, as confirmed by laboratory methods. Moreover, this PCR assay could identify a number of untypable Shigella strains (Sh OUT), which would have remained undiagnosed had this assay not been used.  (+info)