John E. Corkill

Non-typhoidal salmonella bacteraemia among HIV-infected Malawian adults: high mortality and frequent recrudescence

ObjectiveNon-typhoidal salmonella (NTS) bacteraemia is a common, recurrent illness in HIV-infected African adults. We aimed to describe the presentation and outcome of NTS bacteraemia, the pattern of recurrence, and to determine whether recurrence results from re-infection or recrudescence. DesignOne hundred consecutive adult inpatients with NTS bacteraemia in Blantyre, Malawi, were treated with chloramphenicol. Survivors were prospectively followed to detect bacteraemic recurrence. MethodsIndex and recurrent isolates were typed by antibiogram, pulsed-field gel electrophoresis and plasmid analysis to distinguish recrudescence from re-infection. ResultsInpatient mortality was 47%, and 1-year mortality was 77%. A total of 77 out of 78 cases were HIV positive. Anaemia was associated with inpatient death, and several features of AIDS were associated with poor outpatient survival. Among survivors, 43% (19/44) had a first recurrence of NTS bacteraemia at 23–186 days. Among these, 26% (5/19) developed multiple recurrences up to 245 days. No recurrence was seen after 245 days, despite follow-up for up to 609 days (median 214). Suppurative infections were not found at presentation, and were only seen twice at recurrence. Index and recurrent paired isolates were identical by phenotyping and genotyping, consistent with recrudescence, rather than re-infection. ConclusionNTS bacteraemia has a high mortality (47%) and recurrence (43%) rate in HIV-infected African adults. Recurrence is caused by recrudescence rather than re-infection. As focal infections were rarely found, recrudescence may often be a consequence of intracellular tissue sequestration. There is an urgent need for improved primary treatment and secondary prophylaxis in Africa.

Methicillin-resistant staphylococci in companion animals

We determined the molecular characteristics of methicillin-resistant staphylococci from animals and staff at a small animal and equine hospital. Methicillin-resistant Staphylococcus aureus (MRSA) identical to human EMRSA-15 was found in dogs and hospital staff. In contrast, 5 distinct MRSA strains were isolated from horses but not from hospital staff.

Characterization, of epithelial IL-8 response to inflammatory bowel disease mucosal E-coli and its inhibition by mesalamine

Background: Mucosally adherent E. coli are found in inflammatory bowel disease (IBD) and colon cancer. They promote release of the proinflammatory cytokine interleukin‐8 (IL‐8). We explored mechanisms for this release and its inhibition by drugs. Methods: IL‐8 release from colon epithelial cells in response to mucosal E. coli isolates from IBD, colon cancer, and controls was characterized at the cellular and molecular level. Results: IL‐8 response of HT29 cells was greater with Crohns disease (689 ± 298 [mean ± SD] pg IL‐8/mL at 4 hours, n = 7) and colon cancer isolates (532 ± 415 pg/mL, n = 14) than with ulcerative colitis (236 ± 58 pg/mL, n = 6) or control isolates (236 ± 100 pg/mL, n = 6, P < 0.0001). Bacterial supernatants contained shed flagellin that triggered IL‐8 release. For whole bacteria the IL‐8 response to E. coli that agglutinate red blood cells (548 ± 428 pg IL‐8/mL, n = 16), a function that correlates with epithelial invasion, was greater than for nonhemagglutinators (281 ± 253 pg/mL, n = 17; P < 0.0001). This was particularly marked among E. coli that, although flagellate, could not release IL‐8 from TLR5‐transfected HEK293 cells. IL‐8 release was mediated by extracellular‐regulated kinase (ERK) and p38 mitogen‐activated protein kinase (MAPK) and inhibited by mesalamine, but not hydrocortisone, at therapeutic concentrations. Conclusions: Mucosa‐associated E. coli shed flagellin that elicits epithelial IL‐8 release but this may only become relevant when the mucosal barrier is weakened to expose basolateral TLR5. Adherent and invasive IBD and colon cancer E. coli isolates also elicit a flagellin‐independent IL‐8 response that may be relevant when the mucosal barrier is intact. The IL‐8 release is MAPK‐dependent and inhibited by mesalamine.

Excretion of vancomycin-resistant enterococci by wild mammals.

A survey of fecal samples found enterococcal excretion in 82% of 388 bank voles (Clethrionomys glareolus), 92% of 131 woodmice (Apodemus sylvaticus), and 75% of 165 badgers (Meles meles). Vancomycin-resistant enterococci, all Enterococcus faecium of vanA genotype, were excreted by 4.6% of the woodmice and 1.2% of the badgers, but by none of the bank voles.

Isolation of Waddlia malaysiensis ,A Novel Intracellular Bacterium, from Fruit Bat (Eonycteris spelaea)

A novel obligate intracellular bacterium was isolated from urine samples from fruit bats (Eonycterisspelaea) in peninsular Malaysia.

Oxacillinase-mediated resistance to carbapenems in Klebsiella pneumoniae from Lebanon

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A subset of mucosa-associated Escherichia coli isolates from patients with colon cancer, but not Crohn's disease, share pathogenicity islands with urinary pathogenic E. coli

Adherent and invasive mucosa-associated Escherichia coli have been implicated in the pathogenesis of colon cancer and inflammatory bowel diseases. It has been reported that such isolates share features of extraintestinal E. coli (ExPEC) and particularly uropathogenic E. coli (UPEC). We used suppression subtractive hybridization (SSH) to subtract the genome of E. coli K-12 from that of a colon cancer mucosal E. coli isolate. Of the subtracted sequences, 53 % were present in the genomes of one or more of three sequenced UPEC strains but absent from the genome of an enterohaemorrhagic E. coli (EHEC) strain. Of the subtracted sequences, 80 % matched at least one UPEC genome, whereas only 4 % were absent from the UPEC genomes but present in the genome of the EHEC strain. A further genomic subtraction against the UPEC strain 536 enriched for sequences matching mobile genetic elements, other ExPEC strains, and other UPEC strains or commensals, rather than strains associated with gastrointestinal disease. We analysed the distribution of selected subtracted sequences and UPEC-associated pathogenicity islands (PAIs) amongst a panel of mucosa-associated E. coli isolated from colonoscopic biopsies of patients with colon cancer, patients with Crohns disease and controls. This enabled us to identify a group of isolates from colon cancer (30-40 %) carrying multiple genes previously categorized as UPEC-specific and implicated in virulence.

Flagellin gene variation between clinical and environmental isolates of Burkholderia pseudomallei contrasts with the invariance among clinical isolates

The flagellin gene sequence from a clinical isolate of Burkholderia pseudomallei was used to design oligonucleotide primers for PCR/RFLP analysis of flagellin gene variation among clinical and environmental isolates of B. pseudomallei. Genes from four clinical and six environmental isolates were amplified and compared by RFLP. The clinical isolates were indistinguishable, but variation was detected among some of the environmental isolates. Sequence analysis of flagellin gene amplified products demonstrated high levels of conservation amongst the flagellin genes of clinical isolates (>99% similarity), compared to the variation observed between the clinical isolates and one of the environmental isolates (<90% similarity). Genomic comparisons with pulsed-field gel electrophoresis (PFGE) revealed differences between the relationships inferred by flagellin genotyping and PFGE, suggesting that a combination of molecular methods may be useful for the subtyping of B. pseudomallei strains.

Molecular Typing of, and Distribution of Genetic Markers among, Burkholderia cepacia Complex Isolates from Brazil

ABSTRACT PCR tests were used to assign genomovar status to 39 non-cystic fibrosis (non-CF) and 11 CF Burkholderia cepacia complex isolates from patients in hospitals in Recife, Brazil. Non-CF isolates were assigned to genomovar IIIA (71.8%), genomovar I (15.4%), B. vietnamiensis (7.7%), and B. multivorans (5.1%). CF isolates were assigned to genomovar IIIA (18.2%), B. vietnamiensis (18.2%), and genomovar I (9.1%). Six CF isolates sharing recA PCR-restriction fragment length polymorphism (RFLP) and randomly amplified polymorphic DNA (RAPD) patterns could not be assigned to a genomovar. 16S rDNA sequence obtained from these isolates indicated a closest relationship to B. anthina, but the recA sequence was equally divergent from several genomovars. PCR screening indicated the presence of cblA in only two isolates, whereas the B. cepacia epidemic strain marker was found in 22 of 28 genomovar IIIA isolates. A type III secretion gene was detected in all but genomovar I isolates. RAPD and PCR-RFLP assays, targeting both recA and fliC, indicated a large amount of genetic variability among the isolates, with many novel patterns being observed. Nine genomovar IIIA isolates from different non-CF patients and clinical sources had identical genotypes, indicating the presence of a common clone.

Plasmid encoded β-lactamases resistant to inhibition by clavulanic acid produced by calf faecal coliforms

Two new plasmid encoded beta-lactamase enzymes produced by a strain of Escherichia coli and a strain of Citrobacter freundii isolated from calf faeces have been characterised. Both enzymes were similar to TEM-1 in terms of substrate and inhibition profiles and physical properties but differed from TEM-1 in being far less susceptible to the beta-lactamase inhibitors clavulanic acid or tazobactam. In each case transfer of the plasmid E coli K12 rendered it clinically resistant to the combination of amoxycillin and clavulanic acid. The beta-lactamase from the E coli had an iso-electric point (pI) of 5.4 and was encoded on a plasmid of 95 Kbp which also mediated resistance to tetracycline, sulphonamides, apramycin, streptomycin and gentamicin. The beta-lactamase from the C freundii had a pI of 5.2 and was encoded on a 75 Kbp plasmid which also mediated resistance to trimethoprim, chloramphenicol, apramycin, gentamicin and tobramycin.