Beta-lactamase production in Prevotella and in vitro susceptibilities to selected beta-lactam antibiotics [corrected].

This study looked for beta-lactamase production in 100 Prevotella isolates. MICs were determined for amoxycillin, ticarcillin, amoxycillin+clavulanate, cephalothin, cefuroxime, cefixime, cefpodoxime and cefotaxime using the reference agar dilution method (standard M11 A4, NCCLS). Beta-lactamase activity was detected in 58 of the 100 isolates, 24 of 46 black-pigmented Provotella and 34 of 54 non-pigmented Prevotella. All beta-lactamase-negative strains were susceptible to all beta-lactam antibiotics with the exception of cefuroxime and cefixime. Overall, resistance rates of Prevotella strains were lower for ticarcillin (8%) and celefotaxime (12%) than for the other cephalosporins. All Prevotella isolates were susceptible to amoxycillin and were all inhibited by 2 mg/l or less amoxycillin [corrected].

Survey of anaerobic susceptibility patterns: a French multicentre study.

In 1996, the in vitro antibiotic susceptibility of 463 anaerobes was measured in five hospitals using the reference agar dilution method. None of the 209 B. fragilis group strains showed resistance to imipenem or ticarcillin-clavulanic acid. High resistance rates (29%) were observed for cefotetan and clindamycin. beta-Lactamase production was detected respectively in 64% of the Prevotella and 7% of the Fusobacterium strains. Because the same standardized methods were used for many years, the authors were able to evaluate the evolution of antibiotic resistance. Clindamycin resistance had increased within the B. fragilis group (from 14% in 1992 to 29% in 1996) and also among strains of clostridia (32%), P. acnes (18%) and Peptostreptococcus (28%). In the B. fragilis group multidrug resistance was unlikely to occur.

Bacteriology of the adult middle meatus.

The aim of this work was to assess the commensal flora in the adult middle meatus. Thus, 139 samples were taken from subjects of both sexes, over 16 years of age, seen in the community or hospitalized for less than 72 hours for non-rhinological conditions. They had had no nasal or sinus conditions in the previous three months. One hundred and thirteen samples contained at least one aerobic or anaerobic bacterium. Fifty-nine samples yielded a single organism in culture. A maximum of five organisms were isolated from a given patient. These results show that the adult middle meatus contains a mixed commensal flora and should prove useful in interpreting endonasal swab cultures during acute and chronic sinus infection.

Prevalence and pathogenicity of Clostridium difficile in hospitalized patients. A French multicenter study.

BACKGROUND: Although Clostridium difficile is the main agent responsible for nosocomial diarrhea in adults, its prevalence in stool cultures sent to hospital microbiology laboratories is not clearly established. OBJECTIVES: To determine the prevalence of C difficile in inpatient stools sent to hospital microbiology laboratories and to assess the relationship between serotypes and toxigenicity of the strains isolated and the clinical data. METHODS: From January 18, 1993, to July 31, 1993, the presence of C difficile was systematically investigated in a case-control study on 3921 stool samples sent for stool culture to 11 French hospital microbiology laboratories. The prevalence of C difficile in this population (cases) was compared with that of a group of 229 random hospital controls matched for age, department, and length of stay (controls). Stool culture from controls was requested by the laboratory although not prescribed by the clinical staff. Serotype and toxigenesis of the strains isolated were compared. RESULTS: The overall prevalence of C difficile in the cases was twice the prevalence in the controls (9.7% vs 4.8%; P < .001) and was approximately 4 times as high in diarrheal stools (ie, soft or liquid) as in normally formed stools from controls (11.5% vs 3.3%; P < .001). The strains isolated from diarrheal stools were more frequently toxigenic than those isolated from normally formed stools. Serogroup D was never toxigenic, and its proportion was statistically greater in the controls than in the cases (45% vs 18%; chi 2 = 5.2; P < .05). Conversely, serogroup C was isolated only from the cases. Clostridium difficile was mainly found in older patients ( > 65 years), suffering from a severe disabling disease, who had been treated with antibiotics and hospitalized for more than 1 week in long-stay wards or in intensive care. CONCLUSIONS: This multicenter period prevalence study clearly supports the hypothesis of a common role of C difficile in infectious diarrhea in hospitalized patients. Disease associated with C difficile should therefore be systematically evaluated in diarrheal stools from inpatients.

Value of routine stool cultures in hospitalized patients with diarrhea.

In a prospective study conducted over a six-month period, the relative yield of 721 routine cultures of stool from adult inpatients as a function of the time after hospital admission was assessed. Salmonella, Campylobacter, Shigella or Yersinia spp. were recovered from 10.9% (41/377) of patients within three days of hospitalization and from only 1.5% (5/344) after three days. However, a review of these patients' charts did not suggest nosocomial transmission but rather a delay in stool collection or asymptomatic carriage. Clostridium difficile was isolated with a high frequency in patients both within and after three days of hospitalization (10.3% and 10.2%, respectively). Thus, stool specimens from adults hospitalized for more than three days should not be cultured except for Clostridium difficile unless there are plausible clinical or epidemiological reasons to do so.

[In vitro activity of carbapenems (biapenem, imipenem and meropenem) and some other antibiotics against strict anaerobic bacteria]. / Activité in vitro des carbapénèmes (biapénème, imipénème et méropénème) et de quelques antibiotiques sur les anaérobies stricts.

During 1994, the in vitro antibiotic susceptibility of 306 anaerobic bacteria was performed in 4 hospitals, by the reference agar dilution method. Among the 129 B. fragilis group strains, only two B. fragilis strains were resistant to the three carbapenems and all beta-lactams, even combined with beta-lactamase-inhibitors while metronidazole resistance could not be detected. Evolution in antibiotic resistance rates could be assessed only for piperacillin whose resistance rates increased to 20%. beta-lactamase production was detected respectively for 27% of Prevotella and 17% of Fusobacterium strains. No beta-lactamase activity was seen among Gram positive anaerobes. On the whole anaerobic strains resistance rates were: biapenem, imipenem, meropenem and piperacillin-tazobactam 0.7, amoxicillin-clavulanic acid or metronidazole 2, piperacillin 11.3, amoxicillin 31%, respectively. The three carbapenems demonstrated a good in vitro activity against most anaerobes with few differences between them.

Penicillin G/ofloxacin versus erythromycin/amoxicillin-clavulanate in the treatment of severe community-acquired pneumonia.

In a prospective, randomized, multicenter trial, the efficacy of penicillin plus ofloxacin was compared to that of amoxicillin-clavulanate plus erythromycin in the treatment of community-acquired pneumonia. One hundred seventeen hospitalized patients presenting with severe community-acquired pneumonia received either penicillin 3 x 10(6) U/6 h plus ofloxacin 200 mg twice daily (group A) or amoxicillin-clavulanate 1 g/6 h plus erythromycin 1 g/8 h (group B). Initial assessment included clinical examination, determination of simplified acute physiology score (SAPS), chest X-ray and evaluation of microbiological data obtained from blood, sputum and/or bronchoscopy. Follow-up was documented at 72 h and at 30 days. Both groups were comparable for age, sex, SAPS, chest X-ray, hypoxemia and microbiological data. The causative pathogen was identified in 54 cases (53%), Streptococcus pneumoniae being most frequent isolate (54.7%). All organisms cultured were susceptible to at least one of the antibiotics of each combination of the protocol, with the exception of two strains of Pseudomonas aeruginosa. A favorable outcome was observed in 76% of the patients, equally distributed between the two groups. After completion of therapy there were 12 clinical failures in each group (20.5%). Six patients in each group (10.3%) died of infection. Tolerance was similar for both regimens, apart from an increased rate of superficial thrombophlebitis in patients receiving intravenous erythromycin. The combination of penicillin with ofloxacin is as effective and as safe as a previously recommended regimen combining amoxicillin-clavulanate and erythromycin in treating patients with community-acquired pneumonia.

[Susceptibility of strict anaerobic bacteria to antibiotics in France: a multicenter study]. / Sensibilité aux antibiotiques des anaérobies stricts en France: étude multicentrique.

During 1992, the in vitro antibiotic susceptibility of 462 anaerobic bacteria was performed in 7 hospitals, by the reference agar dilution method. Among the 222 Bacteroides fragilis group strains, only one Bacteroides fragilis strain was resistant to imipenem and all bêtalactams, even combined with bêtalactamase-inhibitors while metronidazole resistance could not be detected. One major outer membrane protein (probably a porin) was lacking in some of the six amoxicillin-clavulanic acid resistant Bacteroides fragilis group strains. Evolution in antibiotic resistance rates could be assessed only for clindamycin and piperacillin whose resistance rates increased to 14 and 15.8 p. cent, respectively. On the whole anaerobic strains resistance rates were: imipenem 0.2, ticarcillin-clavulanic acid 0.5, amoxicillin-clavulanic acid or metronidazole 1.5, piperacillin 9.1, cefotaxime-sulbactam 9.7, cefoxitin 12.8, clindamycin 13.7, cefotaxime 27.2, amoxicillin 45 and ciprofloxacin 70, respectively.

[Survey with three epidemiological markers after 22 cases of diarrhea caused by Clostridium difficile in a geriatric hospital]. / Enquête a l'aide de trois marqueurs épidémiologiques après 22 diarrhées a Clostridium difficle dans un hôpital gériatrique.

In a geriatric hospital of Saint-Etienne (Charité), among 153 patients having presented a nosocomial diarrhea from September 1990 to August 1991 Clostridium difficile (C.d.) has been isolated in 22 cases. Two of the nine units of the hospital had the highest incidence rates: 4.6 and 3.7%. In the faeces of 16 patients, C.d. was toxinogenic. In all cases, except one, antibiotic preceded diarrhea. Amoxicillin + clavulanic acid treatment was the most frequently responsible (65%). For detecting an eventual outbreak, several epidemiologic markers were evaluated: Clindamycin MIC, protein profiles, serotyping. Clindamycin susceptibility differentiated two Cd. types, but has no epidemiologic value. Protein profiles, performed by SDS-Page, individualized 6 different profiles, but 10 strains gave no classifiable profiles. Serotyping, applied by M. Delmée, appeared as the most interesting marker. Inquiry allowed to eliminate an outbreak but revealed two episodes of cross contaminations in the 3 units, 2 of them having the highest incidence rates. Markers proved persistence of the same C.d. strain in some patients who were correctly treated by metronidazole.

Survey of the susceptibility patterns of Bacteroides fragilis group strains in France from 1977 to 1992.

Rates of antibiotic resistance within the Bacteroides fragilis group were monitored over a 15-year period in France by examining studies that employed the same methodology to test susceptibility of anaerobic bacteria. Chloramphenicol, metronidazole, beta-lactam/beta-lactamase inhibitor combinations and imipenem remained very active against Bacteroides fragilis. There was little or no change in rates of resistance to these antibiotics. Resistance to clindamycin increased from 1% in 1977 to a peak of 19% in 1987, and since then has remained at 8 to 12%. There was some evidence that resistance to most beta-lactam agents increased during the same period. These results emphasize the need for periodic surveys of resistance patterns of the Bacteroides fragilis group in each country.

[Role of mycoplasmas in the last month of pregnancy and postpartum pathology. Prospective study of 577 pregnancies]. / Rôle des mycoplasmes dans la pathologie du dernier mois de gestation et du post-partum. Etude prospective de 577 grossesses.

The authors report the findings of a prospective study of 577 pregnancies. The purpose of this study was to determine the influence of mycoplasma on peri-post-natal illness arising during the last month of gestation and during the immediate post-partum period. The incidence of contamination was 29% of Ureaplasma urealyticum and 2.3% for Mycoplasma hominis. This showed little change post partum. The rate of transmission to the fetus or placenta is low. No difference in end-of-term fetal weight was detected in comparison with a control population. Ureaplasma urealyticum was significantly associated with premature breaking of the membranes. Mycoplasma hominis was highly significantly associated with post-partum endometritis.

[Clostridium difficile: a typing method for epidemiological studies]. / Clostridium difficile: mise au point d'une méthode de typage pour les études épidémiologiques.

One hundred and twenty two strains of Clostridium difficile were studied: 33 strains were isolated from stools of neonates or children, 89 cases of antibiotic associated diarrhea. The strains were identified by biochemical tests and gaz liquid chromatography of the fermentation products. A typing scheme for Clostridium difficile were proposed by using a polyacrylamide gel electrophoresis of whole cell proteins. We studied the correlation between this typing and the serogrouping scheme based on slide agglutination with a rabbit antisera and previously described by Delmée. The serogrouping defines 10 groups, PAGE allows the differentiation of 12 profiles, with a good correlation between the two methods for some serogroups except for the heterogenous serogroup A.

[Strict anaerobic bacteria: comparative study of various beta-lactam antibiotics in combination with tazobactam or sulbactam]. / Anaérobies stricts: activités comparées de diverses associations de bêtalactamines avec le tazobactam ou le sulbactam.

The minimal inhibitory concentrations of piperacillin (PIP) or cefotaxime (CTX) alone or in combination with tazobactam (TAZ) were determined against 168 anaerobes. All the strains were inhibited by PIP + TAZ, but certain strains resistant to CTX + TAZ were found among B. fragilis, Eubacterium and Peptostreptococcus. The second investigations included 30 strains of Bacteroides fragilis. Concentrations of 2, 4 and 8 mg/l of TAZ and sulbactam (SUL) were combined with piperacillin or cefotaxime. The two beta-lactamase-inhibitors had similar activities when used at 2 or 4 mg/l, but at 8 mg/l TAZ was more active than SUL. All B. fragilis strains were inhibited by PIP + TAZ or PIP + SUL, whereas resistance was observed with CTX + SUL or CTX + TAZ. On the same strains the activities of 6 beta-lactams (PIP, mezlocillin, ticarcillin (TIC), CTX, ceftriaxone and ceftazidime) were determined in combination with either SUL 4 mg/l or TAZ 8 mg/l. Only PIP or TIC + SUL or TAZ were able to inhibit at least 90% of tested strains. No resistance could be detected with PIP + TAZ combination. As conclusion, the two inhibitors when combined with PIP or TIC offered greater activity against both Gram positive or negative anaerobes and PIP + TAZ remained the more potent combination.

A collaborative study of French laboratories to assess any evolution of antibiotic resistance within the Bacteroides fragilis group.

Antibiotic susceptibility testing of anaerobes by a same methodology allows the authors to draw up suggestions about the evolution of antibiotic resistance within the B. fragilis group. Cefoxitin resistance rates were stable until 1985 and were slowly increasing later. Until 1985 piperacillin was able to inhibit all tested strains. In 1987 the two groups noticed an increasing resistance to piperacillin (4 to 9%). During the 1970's clindamycin resistance was a minor event (less than 1%) then the resistance rate increased rapidly to 10% in 1980. MICs determinations from 1981 to 1985 demonstrated well that clindamycin resistance was stable at this 10% rate. Since 1987 the clindamycin resistance was again increasing and reached respectively 14 to 19% for the two groups of investigators. Metronidazole has kept a good activity against Bacteroides fragilis group strains but some strains with reduced susceptibility (MIC 2 to 8 mg/l) have been described since 1983. Three strains with MIC greater than 8 mg/l were recently described by one of the groups. Until 1987, the clavulanic amoxicillin combination was able to inhibit all strains of the B. fragilis group but only imipenem remained still active on all investigated strains with no change at all for the values of MIC50 and MIC90 determined by the investigators of this study. All these results emphasize the need for periodical surveys within the B. fragilis group in each country.

[Azithromycin versus josamycin: treatment of 89 cases of acute pneumonia]. / Azithromycine versus josamycine: traitement de quatre-vingt-neuf pneumopathies aiguës.

In an open, multicenter randomized clinical trial on patients with acute pneumonia, 5-day therapy using a new oral macrolide antibiotic, azithromycin (Az), was compared with standard 10-day therapy using another macrolide, josamycin (J). Eighty-nine patients were treated (46 Az, 43 J); both groups were comparable, except in terms of the sex ratios. The causative agent was determined in 31 cases; streptococcal pneumonia was the most common diagnosis (48%). Cure rates were 93% for J and 80% for Az (p greater than 0.30), as judged by a fall in body temperature and an improvement in clinical condition and in radiographic findings. Among 6 failures, there were 4 cases of empyema (1 J, 3 Az). Of 6 deaths, 2 were pneumonia-dependent (1 J and 1 Az, Haemophilus and Streptococcus pneumoniae, respectively). We conclude that 5-day Az is as effective as 10-day J and that such short-course therapy is an advantage in the treatment of pneumonia caused by macrolide susceptible pathogens.

[Comparative antibacterial activity of cefpodoxime, cefuroxime and cefaclor against strict anaerobic bacteria]. / Activité antibactérienne comparée du cefpodoxime, du cefuroxime et du céfaclor envers les anaérobies stricts.

The in vitro activity of a new cephalosporin (CPX) was assessed against 260 strains of anaerobic bacteria. A comparison was done with two other oral cephalosporins cefaclor (CFA) and cefuroxime (CXM). MICs were determined by an agar-dilution method on wilkins chalgren agar. The three antibiotics had little activity against Bacteroïdes fragilis group. Cefpodoxime was more active than the two other cephalosporins against Fusobacterium and Bacteroïdes spp. At 4 mg/l concentration the percentages of susceptibility were respectively CFA 8% CXM 11% for all the Gram negative bacilli. Inversely, a better activity was detected against Gram positive anaerobes; the three cephalosporins inhibiting respectively CFA 65% CXM 75% CFX 46% of 94 tested strains. All Veillonella spp. and Propionibacteria were inhibited by cefpodoxime 4 mg/l. The activity of the three cephalosporins were similar weak against Gram negative anaerobes but greater against Gram positive strict anaerobes.

[Detection of beta-lactamases in the Bacteroides fragilis group]. / Détection des bêta-lactamases des Bacteroïdes du groupe fragilis.

One hundred and thirty three strains of Bacteroides fragilis group isolated from clinical specimen were tested for beta-lactamase activity against five beta-lactam antibiotics, ampicillin, cefaloridin, cefuroxime, cefotaxime and cefoxitin. The Minimal Inhibitory Concentration of antibiotics was determined using the agar dilution method. Beta-lactamase production was detected by a microbiological method in 128 of the 133 (96%) strains. The detected beta-lactamases had a broad-spectrum activity, hydrolyzing both penicillins and cephalosporins (101 strains). Some strains had a wide activity against beta-lactam antibiotics, including cefoxitin (7 strains); among these strains, 3 were found hydrolyzing imipenem.

Evolution in antibiotic susceptibility of Bacteroides fragilis group strains in France based on periodic surveys.

Anaerobic antibiotic susceptibility testing with standardized methods enabled the authors to speculate on the evolution of antibiotic resistance within the Bacteroides fragilis group strains. Cefoxitin resistance was stable (0-5%) until 1985 and gradually increased later. Clindamycin resistance emerged in 1980 with a stable 10% resistance rate until 1986. An increase in clindamycin resistance developed in three institutions in 1987. No change was detected for imipenem and metronidazole, while piperacillin resistance increased since 1986. A comparison of antibiotic resistance rates is discussed for anaerobes in different countries.

[In vitro activity of a combination of amoxicillin-clavulanic acid on anaerobic bacteria]. / Activité in vitro de l'association amoxicilline-acide clavulanique sur les bactéries anaérobies.

One hundred and one anaerobes isolated from clinical specimen were examined for their susceptibility to amoxicillin, alone or in combination with clavulanic acid, cefoxitin, cefotetan, cefotaxime, piperacillin and metronidazole. Tested strains were as follow: 90 Bacteroides fragilis group, 16 Bacteroides bivius and 5 Clostridium difficile. For 54 strains combination amoxicillin-sulbactam were also studied. Minimal inhibitory concentrations (MICs) were determined by agar dilution method on Wilkins-Chalgren agar. All the strains were susceptible to the combination amoxicillin-clavulanic acid. The mode MIC was 0.5 microgram/ml and 16 micrograms/ml for amoxicillin alone.

[In vitro activity of beta-lactams, clindamycin and metronidazole on Clostridium difficile]. / Activité in vitro des bêtalactamines, de la clindamycine et du métronidazole sur Clostridium difficile.

In one year and a half period 47 Clostridium difficile were isolated from stool samples. Isolates with questionable morphologic features were identified using sugars fermentation, gaz liquid chromatography (GLC). Cytotoxin assay was performed on Mac Coy cells. The comparative susceptibilities to amoxicillin-clavulanic acid (AMC), cefotetan (CTT), cefoxitin (FOX), cefotaxime (CTX), latamoxef (MOX), mezlocillin (MEZ), piperacillin (PIP), clindamycin (CLIN) and metronidazole was tested using minimal inhibition concentration (MIC) determination on Wilkins-Chalgren blood agar. CLIN, FOX, CTX, MOX were inactive, CTT is moderately inactive. All strains were susceptible to AMX, MEZ, PIP and metronidazole.