Late-onset sepsis due to Salmonella Typhi in a preterm infant in a French neonatal unit.

We report a case of late-onset sepsis caused by Salmonella Typhi in a one-month old preterm infant hospitalised in our neonatal unit. An investigation of the index case was undertaken to identify the source of contamination. The patient made a complete recovery.

Prevalence and characterization of extended-spectrum ß-lactamase-producing clinical Salmonella enterica isolates in Dakar, Senegal, from 1999 to 2009.

A total of 1623 clinical isolates of Salmonella belonging to 229 serotypes were received by the Senegalese Reference Center for Enterobacteria from January 1999 to December 2009. The most common serotypes were Enteritidis (19% of the isolates), Typhi (8%), Typhimurium (7%) and Kentucky (4%). A significant increase in the prevalence of resistance to amoxicillin (0.9% in 1999 to 11.1% in 2009) and nalidixic acid (0.9% in 1999 to 26.7% in 2009) was observed in non-typhoidal Salmonella serotypes. For critically important antibiotics, notably ciprofloxacin and extended-spectrum cephalosporins (ESCs), the rates of resistance were low: 0.3% and 0.5%, respectively. Seven ESC-resistant Salmonella strains and three additional ESC-resistant strains from Senegal (1990) and Mali (2007) were studied to identify the genetic basis of their antibiotic resistance. All ESC-resistant strains produced an extended-spectrum ß-lactamase (ESBL). These were CTX-M-15 (n = 6; 2000-2008), SHV-12 (n = 3; 2000-2001) and SHV-2 (n = 1; 1990). A large IncHI2 ST1 pK29-like plasmid was found in six strains (three producing SHV-12 and three CTX-M-15), whereas IncN and IncF plasmids were found in three strains and one strain, respectively. The association of plasmid-mediated quinolone resistance (PMQR) genes qnrB1 and aac(6')-Ib-cr was found in four ESBL-producing strains, leading to decreased susceptibility and even full resistance to ciprofloxacin (MIC range 0.75-2 mg/L) despite the absence of mutations in the quinolone resistance-determining region (QRDR) of gyrA, gyrB, parC and parE. This association of ESBL and multiple PMQR mechanisms within the same strains is therefore a serious concern as it hampers the use of both ESCs and fluoroquinolones for severe Salmonella infections.

[Aetiology of AFB negative pneumonias in hospitalized HIV patients in Dakar]. / Étiologie des pneumonies BAAR négatives chez les patients infectés par le VIH hospitalisés à Dakar (étude ANRS 1260).

A prospective study was carried out in two tertiary hospitals in Dakar to determine the main causes of sputum acid-fast bacillus (AFB) smear-negative pneumonia in HIV-infected patients. All clinical and microbiological records were reviewed by experts. Seventy patients were finally enrolled. Most of them were hospitalized at an advanced stage of AIDS. The median CD4 cell count was 62/mm(3) and the median body mass index (BMC) was 18 kg/m(2). Thirty-one patients (44 %) were known as seropositive for HIV infection prior to admission. Radiological opacities were localized in 70 % of patients and diffuse in 21 %. Fiberoptic bronchoscopy was performed in 50 patients (71 %). A definite or probable diagnosis was obtained in 55 patients (79 %). Bacterial pneumonia (usually due to Enterobacteriaceae and Pseudomonas aeruginosa), tuberculosis, Pneumocystis pneumoniae and other causes (Kaposi's sarcoma, atypical mycobacteria) were diagnosed in 67 %, 24 %, 5 %, and 13 % of these patients respectively. In conclusion, pneumonia of bacterial origin and tuberculosis can be incriminated in the majority of cases of AFB negative pneumonia observed in HIV patients in Dakar.

Antimicrobial Resistance in Outpatient Escherichia coli Urinary Isolates in Dakar; Senegal

Background: Data regarding the evolution of antimicrobial resistance are needed to suggest appropriate empirical treatment of urinary tract infections (UTI) in developing countries. To assess the antimicrobial susceptibility of Escherichia coli; the predominant pathogen in community-acquired UTI; a prospective multicenter study was carried out in Dakar; Senegal. Methodology: From February 2004 to October 2006; 1010 non-duplicate E. coli strains were collected from four centres. Antimicrobial susceptibility testing was performed using disk diffusion method according to the recommendations of the CA-SFM (2004). Results: Most of the isolates were resistant to amoxicillin (73.1); amoxicillin- clavulanic acid (67.5); cephalothin (55.8); and trimethoprim/sulfamethoxazole (68.1). Extended spectrum beta-lactamase was detected in 38 strains. The overall resistance rates to nalidixic acid; norfloxacin and ciprofloxacin were 23.9; 16.4and 15.5; respectively. Most of the strains were susceptible to gentamicin; nitrofurantoin and fosfomycin (respective susceptibility rates; 93.8; 89.9; and 99.3). During this period; a significant decrease in sensitivity was observed for cephalothin; fluoroquinolones and trimethoprim/sulfamethoxazole (p0.001). Conclusions: These data suggest that trimethoprim/sulfamethoxazole may no longer be used as empirical treatment for community- acquired UTI in Dakar. In order to preserve the activity of fluoroquinolones for future years; alternatives such as fosfomycin or nitrofurantoin should be considered

Class 2 integron-associated antibiotic resistance in Shigella sonnei isolates in Dakar, Senegal.

Forty-three Shigella sonnei isolates from adult patients with diarrhoea in Dakar were analysed for the presence of integrons. Isolates were resistant to sulphamethoxazole, trimethoprim, tetracycline, streptomycin and spectinomycin. A high prevalence of class 2 integrons (93%) was found. These integrons showed three distinct structures: a class 2 integron, part of the Tn7 family and its derivatives, carrying four cassettes in the order dfrA1-sat-aadA1-orfX; a truncated class 2 integron, without orfX; and a third type ca. 4 kb in size. These class 2 integrons probably play a role in the spread of multiresistance in S. sonnei isolates. To our knowledge, this is the first description of class 2 integrons in S. sonnei isolated in sub-Saharan Africa.

Biotyping, ribotyping and esterase electrophoresis as epidemiological tools for Acinetobacter baumannii.

An epidemiological survey was carried out over a one-week period to assess the spread of Acinetobacter baumannii in a medical intensive care unit. Fifty strains were isolated from patients colonized or infected by the organism and from a hospital environment. These strains belonged to biotypes 9 or 18. The rRNA gene restriction patterns (using EcoRI and PvuII as restriction endonucleases) and the esterase electrophoretic profiles were determined on 31 strains, using as comparison strain isolates from another intensive care unit of our hospital and from two other French hospitals. Four EcoRI ribotypes, four PvuII ribotypes and six esterase profiles were identified. All biotype 9 strains isolated in our hospital presented the same ribotype after EcoRI digestion, the same ribotype after PvuII digestion and the same zymotype. The same observation was made on most of the biotype 18 strains. Biotyping is an appropriate method for screening of strains, and ribotyping and esterase electrophoresis could be used as additional methods to delineate outbreaks of nosocomial infections caused by A. baumannii.

Continuous ambulatory peritoneal dialysis: evaluation of three new culture methods.

Out of 900 dialysates analysed over 15 months at the Rennes Regional Hospital, 116 cloudy specimens with a leucocyte count of more than 100/mm3 were studied. Three methods of laboratory diagnosis based on physical or chemical disruption of leucocytes were evaluated: saponin incorporated in the agar medium, sonication, and the Isolator lysis centrifugation system. Sensitivity was improved (52%) for the three methods combined compared with the standard method (37%). The Isolator system (51%, P < 0.05) gave the best results. Direct microscopic examination nevertheless remains essential for its indicative value (sensitivity 33% of positive dialysates). The leucocyte count was correlated with the percentage of culture positivity (43% from 100-200/mm3 compared with 62% from 500-1000/mm3); 80% of organisms were Gram-positive bacteria and most were coagulase-negative staphylococci. Opportunistic pathogens such as Corynebacterium jeikeium were frequently isolated.

Esterase electrophoresis compared with biotyping for epidemiological typing of Acinetobacter baumannii strains.

Forty-nine Acinetobacter baumannii strains belonging to three biotypes and isolated from four hospitals were differentiated by electrophoretic typing of their esterases. Six main kinds of esterases were distinguished by their spectra of hydrolytic activity toward seven synthetic substrates. The electrophoretic variations of these enzymes were used to define ten zymotypes among the three biotypes. Esterase electrophoresis appeared to be more sensitive than biotyping, and could represent an additional marker for epidemiological analysis.

Septicemia and hepatic abscess caused by Pediococcus acidilactici.

A case of postoperative Pediococcus acidilactici septicemia with parallel isolation of the organism from hepatic specimens is presented. Laboratory methods to identify this vancomycin-resistant gram-positive cocci are described. Very few cases of documented infections due to this bacterium have been reported in the literature.