Dissemination of extended-spectrum beta-lactamase-producing bacteria: the food-borne outbreak lesson.

OBJECTIVES: Commensal and opportunistic bacteria producing extended-spectrum beta-lactamases (ESBL-PB) have undergone a broad and rapid spread within the general population; however, the routes of dissemination have not been totally elucidated. The aim of this study was to determine whether individuals involved in an outbreak of acute gastroenteritis, in addition to the enteropathogenic microorganism, share an ESBL-PB as indirect demonstration of its transmission from a common food source. METHODS: From 2003 to 2004 in Barcelona, Spain, stool samples from 905 people involved in 132 acute gastroenteritis outbreaks and 226 food handlers related to the outbreaks were investigated. RESULTS: In 31 outbreaks, 58 diners carrying one or more ESBL-PB were detected. In 10 outbreaks, two or more diners shared the same ESBL-PB, and in four of them, the strain was shared with the food handlers. CONCLUSIONS: This study provides circumstantial evidence that foods can be a transmission vector for ESBL-PB, probably from two reservoirs, food animals and food handlers.

Prevalence of qnr genes among extended-spectrum beta-lactamase-producing enterobacterial isolates in Barcelona, Spain.

OBJECTIVES: To evaluate the presence of qnr genes among enterobacterial isolates carrying extended-spectrum beta-lactamases (ESBLs) in Barcelona, Spain. METHODS: Screening for the qnrA, qnrB and qnrS genes was carried out by PCR amplification with specific primers in 305 non-duplicate, clinically relevant ESBL-producing enterobacterial isolates obtained from February 2003 to August 2004. ESBLs from all qnr-positive isolates were characterized by isoelectric focusing, PCR amplification and DNA sequencing. Plasmid analysis was performed by S1 digestion and hybridization with specific probes for the qnr and bla genes. Plasmids containing qnr genes were transferred by conjugation or transformation. The genetic environment of qnrA1 in selected isolates was characterized by cloning experiments. RESULTS: Fifteen isolates, each from a different individual, carried qnr. Among them, 14 had qnrA1 (6 Klebsiella pneumoniae, 6 Enterobacter cloacae and 2 Escherichia coli isolates) and 1 had qnrS1 (K. pneumoniae). None of the isolates carried qnrB. Among the qnrA1-carrying isolates, 10 possessed both bla(CTX-M-9) and bla(SHV-12), 2 had both bla(CTX-M-9) and bla(SHV-92) and 2 had bla(CTX-M-9) alone. The isolate with qnrS1 possessed bla(SHV-12). The qnrA1 and ESBL genes were located together on plasmids ranging in size from 40 to 320 kb. qnrS1 and bla(SHV-12) were not located on the same plasmid. Transfer of quinolone resistance was successfully achieved from all but three isolates. The cloned region surrounding qnrA in two K. pneumoniae isolates revealed a novel genetic organization. CONCLUSIONS: The prevalence of qnr among enterobacterial clinical isolates carrying ESBLs between 2003 and 2004 in Barcelona was 4.9%. qnrA1 was the most prevalent, whereas only one qnrS and no qnrB were detected.

In vivo reversion to the wild-type beta-lactam resistance phenotype mediated by a plasmid carrying ampR and qnrA1 in Enterobacter cloacae.

Resistance to beta-lactams and quinolones in two isogenic Enterobacter cloacae isolates was studied. One was susceptible to cefoxitin and amoxicillin-clavulanate. The other one showed its natural beta-lactam resistance pattern. Both isolates had a nonfunctional AmpR regulator. However, within the second one, the presence of a plasmid carrying ampR and qnrA1 allowed reversion to the wild-type beta-lactam resistance phenotype and decreased susceptibility to fluoroquinolones.

[Role of Lactobacillus as protector against vaginal candidiasis]. / Papel de Lactobacillus como factor protector de la candidiasis vaginal.

BACKGROUND: To evaluate the possible protector role of Lactobacillus against vaginal candidiasis. PATIENTS AND METHOD: In vitro studies performed to assess the capacity of 15 Lactobacillus strains to block the adhesion of two Candida albicans and one C. glabrata strain to vaginal epithelial cells and to inhibit the growth of these yeasts. Moreover, the presence of Lactobacillus was analyzed in 115 vaginal exudates from women with vaginal candidiasis. RESULTS: Only 8 of the 15 lactobacilli studied significantly blocked the adhesion of C. albicans Y18 to vaginal cells. Lactobacilli from group III showed the greatest blocking capacity (62.9%), followed by group II (50.6%) and group I (26.1%). In solid assays, none of the 15 Lactobacillus strains studied was able to inhibit growth of the 3 yeasts. However, in liquid assays some lactobacilli evidenced a certain degree of inhibitory power against C. albicans Y17 (35.7%, 41.7% and 38.1% of light transmittance for Lactobacillus groups I, II and III, respectively). Lactobacillus was detected in 89.6% of women with vaginal candidiasis (by microscopy in 87.8% and by culture in 72.2%). CONCLUSIONS: These results lead us to suggest that probably Lactobacillus provides protection against vaginal candidiasis.

Assessment of the capacity of Lactobacillus to inhibit the growth of uropathogens and block their adhesion to vaginal epithelial cells.

To gain insight into the mechanisms by which Lactobacillus blocks the adherence of uropathogens to vaginal epithelial cells and inhibits their growth, 15 Lactobacillus strains and 22 uropathogens were studied. Lactobacilli from hemagglutination group III, identified as Lactobacillus crispatus, showed greater capacity to block uropathogen adherence than those from hemagglutination groups II and I (61.9%, 49.5%, and 52.6% of blockage, respectively). Pseudomonas aeruginosa PA5 and Klebsiella pneumoniae KP7 were the uropathogens most susceptible to blockage, and Staphylococcus aureus SA11 and Proteus mirabilis PM1 were the most resistant. Lactobacillus inhibited uropathogen growth better in liquid assays; the 3 Lactobacillus groups showed similar inhibitory power (72.3%, 71.9%, and 74.2% of light transmittance). P. aeruginosa PA5 was the most inhibited, and Enterococcus species E15 was the least inhibited. There is considerable variation among Lactobacillus strains regarding their adherence to uroepithelium, blockage of uropathogen attachment, and inhibition of uropathogen growth. Although these properties are independent, they may coincide and therefore allow for these strains to balance the vaginal ecosystem and to make them useful as probiotics.

[Maternal-fetal vertical transmission of Haemophilus influenzae and Haemophilus parainfluenzae]. / Transmisión vertical maternofetal de Haemophilus influenzae y Haemophilus parainfluenzae.

BACKGROUND: Maternal-fetal transmission of Haemophilus influenzae (HI) and Haemophilus parainfluenzae (HPI) as well as characteristics of the infection in the neonate have been poorly described. METHODS AND RESULTS: From 1982 to 1994 18 HI and 12 HPI from vaginal secretion of 30 women obtained intrapartum or immediately post partum were isolated. The following was observed in the 18 patients in whom HI was isolated: 1 abortion, 2 antepartum death, 1 post partum death, and 14 live neonates from whom 10 were suspect a infection with 5 cases being confirmed with isolation of HI in blood culture. Mortality was 40%. The rate of vertical transmission of HI was 80% (8/10) and neonatal sepsis 50% (5/10) (71.4% of the infants whose mothers did not receive intrapartum antibiotics and 0% in those who did). Twenty-seven point seven percent of the strains of HI were beta-lactamase producers with II and III being the most frequent biotypes observed. Of the 12 patients from whom HPI was isolated the following was reported: 1 antepartum death, and 12 live neonates of whom 10 were suspect a infection, but no case was confirmed because HPI was not isolated from blood culture. The vertical transmission of HPI was 20% (2/10). CONCLUSIONS: The isolation of HI in the vagina of pregnant women should be considered as being potentially very virulent since despite a low prevalence, the rate of vertical transmission and, overall, neonatal sepsis, is high.

[Multi-resistant strains of Salmonella typhi in Spain]. / Estudio de cepas multirresistentes de Salmonella typhi en España.

Most Salmonella typhi isolated in Spain are susceptible to antibiotics commonly used in its treatment as chloramphenicol, ampicillin and cotrimoxazole. Three multiresistant strains have been isolated from different patients the last two years. Two phage type M1, biotype xylose tetrationate + strains were isolated from blood of two patients in Bembibre (León). One phage type E1a biotype xylose + tetrationate reductase + strain was isolated from blood and faeces of one patient in Barcelona. All strains harboured a 79 Mdal plasmid responsible for multiresistance, chloramphenicol acetyl transferase production and conjugative.

[Acute gastroenteritis due to Vibrio parahaemolyticus in Spain. Presentation of 8 cases]. / Gastroenteritis aguda por Vibrio parahaemolyticus en España. Presentación de 8 casos.

Eight cases of acute gastroenteritis caused by Vibrio parahaemolyticus in humans are described; to our knowledge, they are the first such reported cases in Spain. All cases appeared between August 20th and October 15th, with a frequency of 8.3% regarding the overall adult patients with acute gastroenteritis, and 11.5% regarding the overall patients with positive stool culture for any enteropathogenic organism. The eight strains were Kanagawa positive and in three patients other enteropathogenic organisms were isolated in addition to Vibrio parahaemolyticus, i.e. Aeromonas hydrophila in two and Salmonella serovariety enteritidis in another. In all cases fish or shellfish had been ingested outside the patients' homes; except for one patient, who ate living clams in the seaside of Galicia, all patients ingested them at seaside restaurants from the Barcelona province. The clinical features of acute gastroenteritis were definite in all patients, but no patients had significant electrolyte losses or required hospital admission. Recovery was spontaneous and no antimicrobial agents were required. All strains were sensitive to tetracyclines, aminoglycosides, cefotaxime, ceftazidime and nearly always to co-trimoxazole.