Diversity of Listeria monocytogenes Strains of Clinical and Food Chain Origins in Belgium between 1985 and 2014.

Listeriosis is a rare but severe disease, mainly caused by Listeria monocytogenes. This study shows the results of the laboratory-based surveillance of Listeriosis in Belgium over the period 1985-2014. Besides the incidence and some demographic data we present also more detailed microbiological and molecular characteristics of human strains isolated since 2000. The strains from the latter period were compared to food and animal strains from the same period. Our study shows that different food matrices were commonly contaminated with L. monocytogenes presenting the same PFGE profile as in patient's isolates. Since 1985, we observed a significant decrease in incidence of the Materno-Neonatal cases (from 0.15 to 0.04 cases /100,000 inhabitants-year), which is probably to be attributed to active prevention campaigns targeting pregnant women. Despite the strengthening of different control measures by the food industry, the incidence of non-Materno-Neonatal listeriosis increased in Belgium (from 0.3 to 0.7 cases /100,000 inhabitants-year), probably due to the rise of highly susceptible patients in an aging population. This significant increase found in non-Materno-Neonatal cases (slope coefficient 7.42%/year, P<0.0001) can be attributed to significant increase in incidence of isolates belonging to serovars 1/2a (n = 393, slope coefficient 6.62%/year, P<0.0001). Although resistance to antimicrobials is rare among L. monocytogenes isolates, a trend to increasing MIC values is evident with chloramphenicol, amoxicillin, tetracycline and ciprofloxacin. We show that fluoroquinolone resistance is not linked to chromosomal mutations, but caused by a variety of efflux pumps. Our study also shows that huge majority of known underlying pathologies (426 out of 785 cases) were cancers (185/426, 43.1%) and haematological malignancies (75/185, 40.5%). Moreover the risk population is susceptible to low levels of contamination in food stressing the need of prevention campaigns specifically targeting these persons.

Epidemic increase in Salmonella bloodstream infection in children, Bwamanda, the Democratic Republic of Congo.

Salmonella enterica is the leading cause of bloodstream infection in children in sub-Saharan Africa, but few data are available from Central-Africa. We documented during the period November 2011 to May 2012 an epidemic increase in invasive Salmonella bloodstream infections in HGR Bwamanda, a referral hospital in Equateur Province, DR Congo. Salmonella spp. represented 90.4 % (103 out of 114) of clinically significant blood culture isolates and comprised Salmonella Typhimurium (54.4 %, 56 out of 103), Salmonella Enteritidis (28.2 %, 29 out of 103) and Salmonella Typhi (17.5 %, 18 out of 103), with Salmonella Enteritidis accounting for most of the increase. Most (82 out of 103, 79.6 %) isolates were obtained from children < 5 years old. Median ages of patients infected with Salmonella Typhimurium and Salmonella Enteritidis were 14 months (14 days to 64 years) and 19 months (3 months to 8 years) respectively. Clinical presentation was non-specific; the in-hospital case fatality rate was 11.1 %. More than two thirds (69.7 %, 53 out of 76) of children < 5 years for whom laboratory data were available had Plasmodium falciparum infection. Most (83/85, 97.6 %) non-typhoid Salmonella isolates as well as 6/18 (33.3 %) Salmonella Typhi isolates were multidrug resistant (i.e. resistant to the first-line oral antibiotics amoxicillin, trimethoprim-sulfamethoxazole and chloramphenicol), one (1.0 %) Salmonella Typhimurium had decreased ciprofloxacin susceptibility owing to a point mutation in the gyrA gene (Gly81Cys). Multilocus variable-number tandem-repeat (MLVA) analysis of the Salmonella Enteritidis isolates revealed closely related patterns comprising three major and four minor profiles, with differences limited to one out of five loci. These data show an epidemic increase in clonally related multidrug-resistant Salmonella bloodstream infection in children in DR Congo.

[Hooping cough in adults, think about it!]. / Coqueluche chez l'adulte, pensez-y!

We report the case of a 47 year old patient who had been suffering from persistent cough for more than three weeks. Patient coughed predominantly during night time, without fever. The amoxicillin-clavulanic acid initially prescribed was not effective. A series of complementary investigations were performed before serology finally identified Bordetella pertussis infection after two months of symptoms which improved slowly without evident benefit of macrolide treatment. The diagnosis of whooping cough was also established for the wife of the patient with fast resolution of the symptoms after rapid unset of treatment with macrolides.

Favourable outcome in a patient bitten by a rabid bat infected with the European bat lyssavirus-1.

The classic rabies virus (genotype 1) has been eliminated in Western Europe, but related lyssaviruses still circulate in local bats. In August 2010, a Belgian photographer was bitten upon provocation of a disoriented Eptesicus serotinus bat in Spain. The bat was infected with European bat lyssavirus-1 (genotype 5). The isolate proved highly neurovirulent in mice. The patient had received preventive rabies immunisations years before the incident and received two boosters with the HDCV rabies vaccine afterwards. Available vaccines are based on the classic rabies virus, which is significantly divergent from the European bat lyssavirus-1. Fortunately, the patient's serological immune response demonstrated satisfactory neutralisation of the 2010 EBLV-1 isolate, using an intracerebral challenge model in mice. Most likely, the patient's life was saved thanks to vaccination with the classic rabies vaccine, which proved sufficiently protective against European bat lyssavirus-1. This case highlights the need for preventive rabies vaccination in people, who come in contact with bats and to seek medical council after a scratch or bite from a bat.

Transmission of multiple resistant Salmonella Concord from internationally adopted children to their adoptive families and social environment: proposition of guidelines.

Since 2004, an increasing number of multidrug-resistant Salmonella serovar Concord infections have been isolated in Belgium among children adopted from Ethiopia. The patients or their family were interviewed and the isolates were subtyped. Between 2004 and 2009, a total of 39 Salmonella Concord infections were isolated from patients. Thirty-four isolates presented a multidrug resistance including resistance to extended-spectrum cephalosporins. Thirty-six cases involved children and 30 of these were adopted from Ethiopia. One case was due to contact with an adopted child and for the other 5 cases no direct epidemiological link with Ethiopia could be found, although four isolates displayed the same patterns observed on the adoptees' isolates, strongly suggesting a phylogenetic relationship with the Ethiopian isolates. Our study confirmed the emergence in Europe of S. Concord isolates resistant to third-generation cephalosporin among Ethiopian adoptees. We have demonstrated that transmission (intra- and extra familial) can happen even if the frequency seems to be low. The presence and the transmission of such a multidrug-resistant Salmonella infection constitute a major concern, since such strains could jeopardize classical antibiotic therapy in patients at risk. This study provides useful information for parents adopting children and for their family practitioner.

The use of spa and phage typing for characterization of a MRSA population in a Belgian hospital: comparison between 2002 and 2007.

UNLABELLED: TARGET OF THE STUDY: Strain typing of pathogens is essential to pinpoint the sources and routes of transmission and to forecast future trends. In a general hospital, we studied possible changes in the MRSA population. PATIENTS AND METHODS: MRSA isolates received from a Belgian general hospital, during 2002 (n=150) and the second half of 2007 (n=105), were compared by phage and spa typing. RESULTS: In 2002, [J]* phage types characterized 45% of the MRSA isolates, 13% belonged to the [O]* phage types, 12% to a local phage type 29/42E/54/D11* and 28% were not assigned to a defined group. Thirteen different spa types were found among the isolates: 39% belonged to t038, 27% to t121, 14% to t041, 5% to t740, and 4% to t002 and t024 each. Two spa types were found respectively in two and three isolates, five were unique. In 2007, 35% belonged to [J]*, 23% to [O]* and 39% could not be put in a defined group. Eighteen different spa types were found: 30% belonged to t740, 29% to t121, 13% to t038 and 10% to t002. Three spa types were represented in two isolates, eleven were unique. The t041 spa type was specific for the 29/42E/54/D11* and the majority of the t121 isolates were related to [J]*. CONCLUSION: [J]* remained the dominant phage types group but decreased whereas [O]*, the second phage types group, increased. As to the spa types, t740 became dominant while t121 remained second. Phage and spa typing point to some quantitative changes among the Belgian MRSA population.

10th survey of antimicrobial resistance in noninvasive clinical isolates of Streptococcus pneumoniae collected in Belgium during winter 2007-2008.

OBJECTIVES: The aim of the study was to evaluate the antibiotic resistance in noninvasive clinical isolates of Streptococcus pneumoniae collected in Belgium during winter 2008-2007. METHOD: Four hundred and forty eight unduplicated isolates collected by 15 laboratories were tested by microdilution following CLSI. RESULTS: Insusceptibility rates (I+R) were as follows: penicillin G (PEN) 11.6% (4.0% R), ampicillin 11.4% (4.0% R), amoxicillin+/-clavulanic acid 0, cefaclor 10.3% (9.6% R), cefuroxime 9.2% (8.7% R), cefuroxime-axetil 8.7% (7.8% R), cefotaxime, ceftazidime and cefepime 2.0% (0% R), imipenem 2.5% (0% R), ciprofloxacin and ofloxacin 5.1% (0.4% R), levofloxacin 0.7% (0.4% R), moxifloxacin 0.4% (0.2% R), erythromycin (ERY) 29.7% (29.2% R), azithromycin 29.7% (28.8% R), telithromycin 0%, clindamycin 26.3% (25.4% R) and tetracycline (TET) 21.9% (16.5% R). From 2001 to 2008, a significant decrease in penicillin-insusceptibility (21.0% to 11.6%), penicillin-resistance (9.7% to 4.0%) and ciprofloxacin-insusceptibility (11.2% to 5.1%) was found. Cross-resistance between penicillin and other betalactams in penicillin-insusceptible isolates was incomplete: all these isolates remained fully susceptible to amoxicillin. Erythromycin-insusceptibility was significantly higher in children than in adults (43.9%/27.4%), while penicillin-insusceptibility significantly higher in Brussels than in the Flanders (22.9%/8.1%). The commonest resistance phenotype was ERY-TET (12.7%) followed by ERY (7.4%) and PEN-ERY-TET (5.8%). Capsular types 19 (25%), 14 (19.3%), 23 (15.4%) and 15 (13.5%) were the most important in penicillin-insusceptible. CONCLUSION: We noted a decrease in resistance to the majority of the compounds. Insusceptibility rates were higher in children than in adults and the difference between the north and the south of Belgium became less marked.

New phage type among methicillin-resistant Staphylococcus aureus associated with a local outbreak in Belgium during 2002.

In total, 150 methicillin-resistant Staphylococcus aureus (MRSA) isolates collected during 2002 from a general Belgian hospital were phage-typed at routine test dilution x 100. The majority (45%) belonged to phage group (J)*, while 10% were classified as a new phage type 29/(42E)/54/(D11)*. The isolates belonging to this new type carried the aac(6')-aph(2'') and the aph(3') aminoglycoside resistance genes and showed high-level resistance to oxacillin. Molecular typing revealed that they belonged to the multiresistant clonal pulsed-field gel electrophoresis (PFGE) type D8. PFGE group D, characterised as genotype ST228-MRSA-I, has been present in Belgian hospitals since 1999.

Surveillance of antibiotic resistance in non invasive clinical isolates of Streptococcus pneumoniae collected in Belgium during winters 2003 and 2004.

A total of 391 and 424 non-invasive isolates of Streptococcus pneumoniae collected by 15 laboratories during the 2003 and 2004 survey were tested for their susceptibility by a microdilution technique following NCCLS recommendations. Insusceptibility rates (IR) in the two surveys (2003/2004) were as follows: penicillin 15.0/14.7% [8.4/6.4% Resistance (R)], ampicillin 17.4/14.6% (R 9.0/7.1%), amoxicillin +/- clavulanic acid 2.6/1.2 % (R 0/0%), cefaclor 14.3/14.1% (R 11.5/13.4%), cefuroxime 13.6/12.7% (R 10.5/11.8%), cefuroxime-axetil 10.5/11.8% (R 10.0/9.2%) (breakpoints based on 250 mg), cefotaxime 4.9/6.2% (R 1.3/2.4%), ceftazidime NotTested (NT)/6.4 (R NT/2.6%), cefepime NT/6.4 (R NT/2.6%), imipenem 7.7/8.9 % (R 1.8/1.4%), ertapenem 0.8/NT% (R O/NT%), ciprofloxacin 13.8/9.0% (R 4.3/2.4%), levofloxacin 3.3/2.8% (R 1.5/0.2%), moxifloxacin 0.6/0.2% (R 0.3/0%), ofloxacin 13.5/9.0% (R 4.3/2.4%), erythromycin 26.1/24.7% (R 25.3/24.5%), azithromycin 25.4/24.7% (R 24.6/24.5%), telithromycin 0.8/0.2% (R 0.5/0%), clindamycin 21.2/18.4% (R 19.2/17.7%) and tetracycline 32.3/22.1% (R 29.2/19.3%). There were only minor differences in resistance rates according to age, sample site, admission type (i.e. ambulatory, hospitalized or long-term care facility patients), gender and geographic origin. Overall, telithromycin (MIC50, MIC90 in 2003/2004: 0.015 microg/ml, 0.12 microg/ml/ 0.008,0.06 respectively), ertapenem (0.03; 0.25/NT), moxifloxacin (0.06; 0.25/0.06, 0.12), and amoxicillin +/- clavulanic acid (0.03; 0.25/0.015, 0.5) were the most active compounds in both surveys. In 2003, the most common resistance phenotype was isolated insusceptibility to tetracycline (10.5%) followed by combined insusceptibility to erythromycin and tetracycline (9.3%). Erythromycin-tetracycline resistance (10.4%) was the most common in 2004. Isolates showing resistance to an antibiotic were significantly more present in 2003 than in 2004 (50.4% versus 40.8%). In penicillin-insusceptible isolates, MICs of all beta-lactams were increased but cross-resistance between penicillin and other beta-lactams in the penicillin-insusceptible isolates was not complete. In the 2003 survey, most of these isolates remained fully susceptible to ertapenem (94.9%) and amoxicillin +/- clavulanic acid (83.1%). In the 2004 survey, 91.9% of the penicillin insusceptible isolates remained susceptible to amoxicillin +/- clavulanic acid. In both surveys, the most common serotypes in penicillin insusceptible isolates were 14, 23,19 and 9 (20.0%, 20.0%, 16.4% and 10.9% respectively in 2003; 41.6%, 11.7%, 15.0% and 18.3% respectively in 2004).

A change in Belgian epidemic methicillin-resistant Staphylococcus aureus phage types in 2000: phenotypic and genotypic characterization of isolates from a general hospital.

During 2000, new methicillin-resistant Staphylococcus aureus (MRSA) epidemic phage types became preponderant in Belgium. In the present study, phenotypic and genotypic characteristics of 130 MRSA isolates from a general Belgian hospital were investigated. The MRSA nature of the isolates was confirmed by coagulase test, oxacillin screen plate test and detection of the mecA gene by polymerase chain reaction. Phage typing categorized the MRSA strains into two main groups: the [O]* types and the [J]* types. SmaI macrorestriction analysis by pulsed-field gel electrophoresis gave the same pulsotype in the majority of strains. All strains of the [O]* and [J]* groups, except one, belonged to this pulsotype. Aminoglycoside-modifying-enzyme genes could only be detected in a minority of strains. Although the epidemic phage types of the mid-1990s appear to have been supplanted by the [O]* and [J]* groups, the MRSA population examined showed a remarkably uniform profile corresponding to the previous major clone B.

High prevalence of penicillin resistance and comparative in vitro activity of various antibiotics in clinical isolates of streptococcus pneumoniae isolated in the Province of Hainaut during winter 2004.

A total of 154 isolates of Streptococcus pneumoniae obtained from 8 different centres in the province of Hainaut were included in this study. The susceptibilities to penicillin, amoxicillin, cefuroxime, ciprofloxacin, moxifloxacin, erythromycin and tetracycline were determined by a microdilution technique following NCCLS recommendations. Decreased susceptibility to penicillin was 32.5% (23.4% intermediate and 9.1% high-level). The other insusceptibility rates were as follows: amoxicillin 1.9% [0% Resistance (R)], cefuroxime 23.4% (R 22.1%), ciprofloxacin 9.1% (R 1.3%), erythromycin 39.6% (R 38.3%), and tetracycline 31.8% (R 30.5%). No decreased susceptibility was found for moxifloxacin. MICs of amoxicillin, cefuroxime, erythromycin and tetracycline rose with those of penicillin for penicillin-insusceptible isolates. Most penicillin-insusceptible isolates remained fully susceptible to amoxicillin (94%), while moxifloxacin and ciprofloxacin kept an activity on 100% and 92% of these isolates respectively. Phenotypes with triple or quadruple insusceptibility were present in 31.2% of the isolates. Penicillin-insusceptible isolates showed a co-insusceptibility of 36.7% to erythromycin, 30.0% to tetracycline and 3.3% to ciprofloxacin.

Antimycobacterial activity of synthetic pamamycins.

OBJECTIVES: Early studies have indicated that pamamycins, a group of macrodiolides first isolated from Streptomyces alboniger, have potent antimicrobial activity against Gram-positive bacteria, fungi and mycobacteria but not against Gram-negative bacteria. The recent availability of highly purified and reasonable quantities of several pamamycins through their total syntheses has rendered possible more extensive studies on their effects on mycobacteria. METHODS: Bioluminescent strains of Mycobacterium tuberculosis, Mycobacterium bovis BCG and Mycobacterium smegmatis, expressing the luxA and luxB genes from Vibrio harveyi were used for the comparison of the antimycobacterial activity of the two synthetic macrodiolides pamamycin-607 and pamamycin-621A and a non-naturally occurring cyclic dimer of pamamycin-607, i.e. yukomycin. RESULTS: Pamamycin-607 was the most active of the three macrocycles and was more active against M. tuberculosis than against M. smegmatis. Twenty-five clinical isolates of M. tuberculosis were susceptible to pamamycin-607 in a narrow MIC range of 1.5-2.0 mg/L. The new assay was also validated by comparison with the BACTEC radiometric test. CONCLUSION: Rapid screening of a new class of macrocyclic antimycobacterials using bioluminescent mycobacteria identified pamamycin-607 as a potential antituberculous agent. The latter was active against clinical isolates of M. tuberculosis within a narrow MIC range of 1.5-2.0 mg/L irrespective of their resistance to isoniazid or rifampicin. Our findings warrant further investigations.

Ten years phage-typing of Belgian clinical methicillin-resistant Staphylococcus aureus isolates (1992-2001).

Gradual changes have been observed in the phage-types of methicillin-resistant Staphylococcus aureus (MRSA) isolates from Belgian hospitals. A total of 6551 isolates, collected in 93 Belgian hospitals over 10 years (1992-2001), was examined. A decreasing incidence of the main early Belgian epidemic phage-types ([A], [B], [H]*, Jo*) was observed. Since 1997 and 2000, a new series of phage-types ([Hv]*, [J]*, [O]*), which were likely related to the previous group [H]*, have been noted. The general trends were confirmed in two particular hospitals. Local epidemic and/or endemic phage-types were also encountered.

Surveillance of antibiotic resistance in clinical isolates of Streptococcus pneumoniae collected in Belgium during winter 2000-2001.

A total of 314 isolates of Streptococcus pneumoniae collected by 10 different laboratories were tested for their susceptibility by using a microdilution technique following NCCLS recommendations. The following antibiotics were included: penicillin, ampicillin, amoxicillin, amoxicillin/clavulanate, cefaclor, cefuroxime, cefotaxime, imipenem, ciprofloxacin, gemifloxacin, levofloxacin, erythromycin, clarithromycin, azithromycin, miocamycin, clindamycin and tetracycline. The insusceptibility rate (IR) to penicillin was 21.0% [10.8% intermediate (> or = 0.12-1 microgram/mL) and 10.2% high-level (> or = 2 micrograms/mL)], to cefotaxime 7.3% [3.5% intermediate (> or = 1 microgram/mL) and 3.8% high-level (> or = 2 micrograms/mL)], to imipenem 3.8% [3.8% intermediate (> or = 0.25-0.5 microgram/mL) and 0% high-level (> or = 1 microgram/mL)], to ciprofloxacin 11.2% [8.3% intermediate (2 micrograms/mL) and 3.9% high-level (> or = 4 micrograms/mL)], to erythromycin 30.3% [3.5% intermediate (0.5 microgram/mL) and 26.8% high-level (> or = 1 microgram/mL)] and to tetracycline 38.5% [0.9% intermediate (4 micrograms/mL) and 37.6% high-level (> or = 8 micrograms/mL)]. No decreased susceptibility was found for gemifloxacin (> or = 0.5 microgram/mL). This compound was the most active with MIC50, MIC90 and an IR of 0.015 microgram/mL, 0.03 microgram/mL and 0% respectively, followed by amoxicillin/clavulanate, amoxicillin and imipenem (MIC50, MIC90 and IR: 0.015 microgram/mL, 1 microgram/mL, 1.6%/0.015 microgram/mL, 1 microgram/mL, 1.9%/0.008 microgram/mL, 0.12 microgram/mL, 3.8% respectively). Compared to the 1999 surveillance, penicillin and tetracycline-insusceptibility increased with 4.9% and 15.6% respectively, while cefotaxime, erythromycin and ciprofloxacin insusceptibility decreased with 5.4%, 5.8% and 4.4% respectively. MICs of all beta-lactams rose with those of penicillin for penicillin-insusceptible isolates. Imipenem, cefotaxime, amoxicillin and amoxicillin/clavulanate were generally 4, 2, 1 and 1 doubling dilutions respectively more potent than penicillin on these isolates while ampicillin, cefuroxime and cefactor were generally 1, 2 and 4 dilutions respectively [table: see text] less potent. Most penicillin-insusceptible isolates remained fully susceptible to amoxicillin/clavulanate (92.4%), amoxicillin (90.9%) and imipenem (81.8%). Erythromycin-tetracycline insusceptibility was the most common resistance phenotype (14.3%). Three- and four-fold resistance was found in 12.4% and 1.6% respectively of the isolates. Most penicillin-insusceptible isolates were of capsular types 14 (22.7%), 23 (21.2%), 6 (18.2%), 9 (13.6%) and 19 (12.1%).

Study of the in vitro activity of amoxicillin/clavulanic acid and other beta-lactam antibiotics against Escherichia coli isolated from urine specimens.

A total of 205 serial, unduplicated urinary isolates of Escherichia coli was collected from June through August 1998 in 2 community and 3 hospital laboratories. By using the NCCLS broth microdilution technique, their in vitro susceptibility to ampicillin, amoxicillin/clavulanic acid, cefuroxime, cefuroxime axetil, ticarcillin/clavulanic acid and piperacillin/tazobactam was determined. One hundred and twenty isolates were from hospitalised patients, 85 from ambulatory, 129 community acquired and 76 nosocomial. Half of the nosocomial isolates were obtained from naturally produced and half from alternatively produced urine specimens. In general, the highest susceptibility rates, following NCCLS criteria, were found for piperacillin/tazobactam (93.2%) followed by cefuroxime (92.2%) and amoxicillin/clavulanic acid (82.9%). Ampicillin showed a clear bimodal distribution with a clear peak for the resistant population. The highest degree of ampicillin resistance was found in nosocomial isolates. Overall, ampicillin showed the lowest degree of susceptibility. Most of the ampicillin resistant isolates remained susceptible to piperacillin/tazobactam, cefuroxime and amoxicillin/clavulanic acid. In general, the community acquired isolates had higher susceptibility rates than the nosocomial isolates.

Comparative in vitro activity of temocillin and other antimicrobial agents against Enterobacteriaceae isolated from patients admitted to five Belgian hospitals.

Temocillin, a methoxy-derivative of the broad-spectrum penicillin, ticarcillin, has been introduced into clinical practice in Belgium in 1988. Since then, not many surveys of its in vitro activity have been published. This study addresses this issue in a prospective collection of 300 consecutive Gram-negative isolates originating from in-patients in five general hospitals throughout Belgium. In addition to temocillin, seven common antibiotics were tested: amoxicillin-clavulanate, piperacillin-tazobactam, cefotaxime, aztreonam, meropenem, ciprofloxacin and amikacin. Meropenem appeared to exhibit the best activity overall, whereas amoxicillin-clavulanate scored the worst. Cumulative MIC plot for two subsets of organisms are given: temocillin, meropenem and cefotaxime are the most active on E. coli and Klebsiella spp., while a significant percentage is resistant to ciprofloxacin and amoxicillin-clavulanate. In the group of inducible Enterobacteriaceae, temocillin, meropenem and amikacin are the most active drugs, while the activity of amoxicillin-clavulanate, piperacillin-tazobactam, cefotaxime and ciprofloxacin is largely decreased. Taking this well preserved in vitro activity of temocillin into account, and looking at its convenient pharmacokinetics and low cost of acquisition, this drug may prove a useful alternative in the treatment of severe nosocomial infections.

In vitro study on the antimicrobial activity of various antibiotics against clinical isolates of Streptococcus pneumoniae from Belgium collected during winter 1998-1999.

A total of 205 isolates of Streptococcus pneumoniae obtained from 10 different centres were included in this study. The susceptibilities to penicillin, ampicillin, amoxicillin, amoxicillin/clavulanic acid, cefaclor, cefuroxime, cefotaxime, imipenem, ciprofloxacin, gemifloxacin, grepafloxacin, levofloxacin, trovafloxacin, erythromycin, clarithromycin, miocamycin, clindamycin and tetracycline were determined by a microdilution technique following NCCLS recommendations. Decreased susceptibility to penicillin was 16.1% [6.8% intermediate (0.12-1 microgram/mL) and 9.3% high-level (> or = 2 micrograms/mL)], cefotaxime insusceptibility (> or = 1 microgram/mL) 12.7%, ciprofloxacine insusceptibility (> or = 2 micrograms/mL) 15.6% with 1.5% of high level resistance (> or = 4 micrograms/mL), erythromycin insusceptibility (> or = 0.5 microgram/mL) 36.1% and tetracycline insusceptibility (> or = 4 micrograms/mL) 22.9%. Decreased susceptibility to cefotaxime was found in 78.8% of the penicillin-insusceptible isolates. No decreased susceptibility was found for gemifloxacin (> or = 0.5 microgram/mL) and trovafloxacin (> or = 1 microgram/mL). Compared to the 1996-1997 surveillance, penicillin, cefotaxime and erythromycin insusceptibility rose by 3.8%, 5.2% and 5.0% respectively, while tetracycline insusceptibility decreased with 8.2%. MICs of all beta-lactams rose with those of penicillin for penicillin-insusceptible isolates. Amoxicillin +/- clavulanate, cefotaxime and imipenem were generally 1, 1 and 5 doubling dilutions respectively more potent than penicillin on these isolates. Penicillin, ampicillin and cefuroxime were equally active while cefaclor was generally 5 dilutions less potent. Most penicillin-insusceptible isolates remained fully susceptible to amoxicillin +/- clavulanate and imipenem. The penicillin-insusceptible isolates were 36.4%, 27.3% and 3.0% co-insusceptible to erythromycin, erythromycin plus tetracycline and tetracycline respectively. A subpopulation of 52 isolates obtained from children aged < or = 3 years was also studied. Compared to the other isolates we found a statistically significant increase in insusceptibility for penicillin, cefaclor, cefuroxime, erythromycin, clarithromycin and tetracycline while a significant decrease was found for ciprofloxacin.

Aminoglycoside resistance in Gram-negative blood isolates from various hospitals in Belgium and the Grand Duchy of Luxembourg. Aminoglycoside Resistance Study Group.

A total of 1102 consecutive clinical blood isolates, including 897 Enterobacteriaceae and 205 non-fermenting bacilli, were obtained from 13 university and university-affiliated hospitals, which were divided into a Northern and a Southern group. Resistance to gentamicin, tobramycin, netilmicin, amikacin and isepamicin was determined using a microdilution technique according to NCCLS procedures. The overall mean resistance level was 5.9% for gentamicin, 7.7% for tobramycin, 7.5% for netilmicin, 2.8% for amikacin and 1.2% for isepamicin. Resistance to amikacin and isepamicin was significantly higher in the Northern hospitals than in the Southern hospitals. In total, 157 isolates were found not to be susceptible to aminoglycosides. By PCR, 179 aminoglycoside resistance mechanisms, i.e. 150 genes encoding modifying enzymes and 29 permeability mechanisms, were detected in 148 isolates. A resistance mechanism could not be detected in nine isolates. Moreover, in a further 14 isolates the resistance profile was not fully explained by the detected genes. The aac(6')-I genes were found to be the most predominant resistance mechanism in both the Northern and Southern isolates, followed by aac(3) genes and permeability resistance. A total of 29 non-susceptible isolates harboured a combination of genes, 72.4% of which were a combination with the aac(6')-lb gene. The majority of these combinations were broad-spectrum combinations which represented 9.0% of the resistance mechanisms in non-susceptible Enterobacteriaceae and 19.3% in the non-fermenting bacilli.

Surveillance of pneumococcal resistance in Belgium during winter 1996-1997.

This study tested 212 pneumococcal isolates from 9 institutions for their susceptibilities to penicillin, ampicillin, amoxycillin, amoxycillin/clavulanate, cefaclor, cefuroxime, cefotaxime, imipenem, tetracycline, erythromycin, and clarithromycin using NCCLS-standardized microdilution. Penicillin-insusceptibility was 12.3% [5.7% intermediate (0.12-1 microgram/ml) and 6.6% high-level (> or = 2 micrograms/ml)], tetracycline-insusceptibility (> or = 4 micrograms/ml) 31.1%, and erythromycin-insusceptibility (> or = 0.5 microgram/ml) 31.1% as well. Erythromycin-insusceptible isolates showed cross-insusceptibility to clarithromycin. Penicillin-susceptible isolates were susceptible to all beta-lactams. MICs of all beta-lactams rose with those of penicillin for penicillin-insusceptible isolates. Ampicillin and penicillin were equally potent against penicillin-insusceptible isolates, imipenem, cefotaxime, and amoxycillin +/- clavulanate were more potent (generally 5, 1, and 1 doubling dilution, respectively), and cefuroxime and cefaclor less potent (generally 1 and 6 doubling dilutions, respectively). Most penicillin-insusceptible isolates were high-level resistant to cefaclor (> or = 32 micrograms/ml). Although MICs of all beta-lactams rose with those of penicillin, resistance to penicillin was not absolute in terms of cross-resistance. Most penicillin-intermediate and high-level penicillin-resistant isolates remained fully susceptible and intermediate, respectively, to amoxycillin +/- clavulanate, cefotaxime, and imipenem, but not to cefuroxime. Penicillin-susceptible isolates were 76.9%, 42.3%, and 34.6% co-insusceptible to tetracycline, erythromycin, and tetracycline plus erythromycin, respectively. Most penicillin-, tetracycline-, and erythromycin-insusceptible isolates were of capsular types 23 >> 6 > 19 > 32, 19 > 6 > 28 > 23, and 19 > 6 > 14 > 23, respectively. Compared to winter 1994-1995, insusceptibility to penicillin, tetracycline, and erythromycin rose by some 4%, 4%, and 13%, respectively.