[Resistance phenotypes and genotypes of 182 ampicillin-resistant Salmonella Typhymurium strains of human and animal origin.]

Among the Salmonellae, an increase in the frequency of antibiotic resistance is mainly observed for S. Typhimurium, one of the most common serotypes encountered in human and animal diseases. One hundred and eighty-two ampicillin-resistant strains of S. Typhimurium, including 82 of human and 100 of animal origin, have been compared. The frequency of tetracycline, sulfonamide, streptomycin and chloramphenicol resistance was high (> 84 %) in both groups, the most common resistance pattern including these four antibiotics. By dot-blotting and hybridization with DNA probes, the genes encoding three types of beta-lactamase were detected. The TEM-type was found in 20 % and 22 % of human and animal strains, the CARB-type in 73 % and 77 %, respectively. The TEM- and CARB-types were found associated in five strains (four from humans an one from animal), and the OXA-2-type in only one human strain. The presence of the CARB-type genes was strongly correlated with that of the integrase (TnpI), independently of the origin of the strains, while the integrase gene in animal strains was also found in ca. 50 % of the strains carrying only TEM-type genes. These results suggest the acquisition and concommittant diffusion, in S. Typhimurium of human and animal origin, of integrons carrying multiple resistance genes including blacarb.

First evidence of bacterial biofilms in the anaerobe part of scalp hair follicles: a pilot comparative study in folliculitis decalvans

BACKGROUND

The cause of folliculitis decalvans (FD) remains unknown. We hypothesized that a bacterial biofilm could be involved in its pathogenesis.

OBJECTIVE

To assess the presence or not of a bacterial biofilm in the hair roots of the scalp in FD.

PATIENTS AND METHODS

Hairs plucked from four patients and three controls were examined by field emission scanning electron microscopy (FESEM) and confocal laser scanning microscopy (CLSM).

RESULTS

Bacterial communities organized as biofilms were observed both by FESEM and CLSM in the under infundibular part of hair follicles in all patients and in two of the three controls. In patients and controls, these biofilms were formed exclusively of bacilli of comparable shapes.

CONCLUSION

This pilot study provides the first evidence of the presence of bacterial biofilms in the infra infundibular part of human scalp hair follicles. These biofilms were detected both in FD patients and controls, suggesting their ubiquity as a commensal biofilm with a possible pathogenic shift in FD.

Absence of community-acquired methicillin-resistant Staphylococcus aureus carriage or infection in a cohort of 300 men who have sex with men attending an inner-city sexually transmitted disease clinic in Paris, France

BACKGROUND

Community-acquired methicillin-resistant Staphylococcus aureus (caMRSA) skin and soft-tissue infections are a major cause for concern. Communities of men who have sex with men (MSM) in the USA being prone to caMRSA epidemics, we investigated whether MSM attending our sexually transmitted disease clinic were carriers of or infected by caMRSA.

METHODS

300 MSM were prospectively recruited, interrogated and examined. Swabs of their nares and of their pubic and perineal skin were taken and cultured.

RESULTS

No evidence of carriage or infection by caMRSA was found. Nasal carriage of methicillin-sensitive S. aureus was within French estimates. Perineal carriage significantly correlated with the number of sexual partners.

CONCLUSION

Although caMRSA carriage or infection does not seem to affect Paris MSM, prospective sampling may not be the best method to monitor them. The correlation between number of partners and perineal carriage suggests that thorough hygiene after intercourse could limit the spread of S. aureus in MSM with multiple partners.

Clostridium difficile infection after allogeneic hematopoietic stem cell transplantation: incidence, risk factors, and outcome

Clostridium difficile (C. difficile) infection was observed in 13% of recipients after hematopoietic stem cell transplantation (HSCT), mainly in the first month posttransplantation. Risk factors were cord blood as the source of stem cells, acute graft-versus-host disease (GVHD), and total body irradiation (TBI). No association was found with an increased risk of mortality. The purpose of this study was to evaluate the incidence, risk factors, and outcome of C. difficile infection (CDI) after HSCT. We conducted a single-center, retrospective, cohort study on all patients who received an allogeneic HSCT from January 2004 to December 2007. All patients with diarrhea in the first year after HSCT were tested for the presence of C. difficile in stools. Among the 407 assessable patients, 53 presented at least 1 CDI in the first year post-HSCT. The total incidence rate was 5.6 cases of CDI per 10,000 patient-days. Fifty percent of cases were diagnosed in the first month after HSCT, and 95% occurred during the first 6 months. Fewer than 5% of patients with CDI had severe diarrhea and severe complications were never observed. TBI in the conditioning regimen, cord blood as the source of stem cells, and acute graft-versus-host disease (aGVHD) were independently associated with CDI. Six patients (11%) had a recurrence of CDI. Four patients required second-line treatment with vancomycin. With a median follow-up of 22 months, the 2-year overall survival rates were similar between patients who presented a CDI and those who did not. CDI was observed in approximately 13% of recipients after HSCT, mainly in the first month posttransplantation and was associated with CB, aGVHD, and TBI. CDI was not associated either with severe complications or with an increased risk of mortality in this large cohort of patients.

[Systematic screening for methicillin-resistant Staphylococcus aureus (MRSA) in the nasal cavities of patients hospitalized in the dermatology departments of the Saint-Louis Hospital]

OBJECTIVES

In a bid to combat methicillin-resistant Staphylococcus aureus (MRSA) more efficiently in our department, we performed a study to 1) clarify the MRSA carriage rate in patients hospitalized in the department; 2) evaluate the rate of MRSA acquisition during hospitalization; 3) describe the MRSA carrier profile; 4) study the morbidity and mortality associated with MRSA.

PATIENTS AND METHODS

We conducted a three-month prospective study in all patients hospitalized for more than 24hours in the dermatology department of the Saint-Louis Hospital. Nasal swab cultures were performed on the day of admission, once a week thereafter and on the day of discharge. Clinical and epidemiological data were individually reviewed by means of a standardized questionnaire.

RESULTS

In 310 patients, the prevalence of nasal MRSA carriage at admission was 6.5%. During hospitalization, 1.9% of our patients became colonized with MRSA. MRSA carriers were significantly older than non-carriers and had been hospitalized more frequently over the previous 12 months, principally in intensive care or in intermediate or long-term care facilities, and erosive and/or ulcerated dermatitis was more common in this population. Of the 27 patients colonized with MRSA, only three had MRSA infections, and these were successfully treated with antibiotics.

DISCUSSION

The observed rate of MRSA carriage was close to that seen in intensive care units (7%). While systematic screening for MRSA in patients with erosive and/or ulcerated dermatitis would allow detection of twice as many cases of MRSA than the usual screening recommendations, this would be associated with little tangible benefit and high costs, and we therefore decided not to change the usual MRSA screening politic in our dermatology department.

Multiple-antibiotic resistance in Salmonella enterica serotype Paratyphi B isolates collected in France between 2000 and 2003 is due mainly to strains harboring Salmonella genomic islands 1, 1-B, and 1-C

This study was conducted to investigate the occurrence of multiple-antibiotic resistance among 261 clinical isolates of Salmonella enterica serotype Paratyphi B strains collected between 2000 and 2003 through the network of the French National Reference Center for Salmonella. The 47 multidrug-resistant (MDR) isolates identified (18%), were characterized on the basis of the presence of several resistance genes (bla(TEM), bla(PSE-1), bla(CTX-M), floR, aadA2, qacEdelta1, and sul1), the presence of Salmonella genomic island 1 (SGI1) by PCR mapping and hybridization, and the clonality of these isolates by several molecular (ribotyping, IS200 profiling, and pulsed-field gel electrophoresis [PFGE]) and phage typing methods. The results of PCR and Southern blot experiments indicated that 39 (83%) of the 47 S. enterica serotype Paratyphi B biotype Java MDR isolates possessed the SGI1 cluster (MDR/SGI1). Among these 39 MDR/SGI1 isolates, only 3 contained variations in SGI1, SGI1-B (n = 1) and SGI1-C (n = 2). The 39 MDR/SGI1 isolates showed the same specific PstI-IS200 profile 1, which contained seven copies from 2.6 to 18 kb. Two PstI ribotypes were found in MDR/SGI1 isolates, RP1 (n = 38) and RP6 (n = 1). Ribotype RP1 was also found in two susceptible strains. Analysis by PFGE using XbaI revealed that all the MDR/SGI1 isolates were grouped in two related clusters, with a similarity percentage of 82%. Isolation of MDR/SGI1 isolates in France was observed mainly between the second quarter of 2001 and the end of 2002. The source of the contamination has not been identified to date. A single isolate possessing the extended-spectrum beta-lactamase bla(CTX-M-15) gene was also identified during the study.

Evaluation of the automated phoenix system for potential routine use in the clinical microbiology laboratory

A comparative study was designed to evaluate the identification (ID) and antimicrobial susceptibility testing (AST) performances of the BD Phoenix Automated Microbiology System (Becton Dickinson Diagnostic Systems [BD], Pont de Claix, France). A total of 305 single clinical isolates were collected, and comparisons were made with routine manual methods in use in our microbiology laboratories. The percentages of correct IDs were 93.3, 89.4, 91.8, and 85.7% for enterobacteria, nonfermenting gram-negative bacilli, staphylococci, and streptococci-enterococci, respectively. The median ID time was 3 h, and the median time for AST was 10 h 30 min. AST results showed variable percentages of errors for the different antibiotics. None of the enterobacteria and 0.3% of Pseudomonas aeruginosa isolates showed a very major error (VME). Only one strain of Staphylococcus aureus showed a VME with oxacillin. We demonstrate here the efficiency of the Phoenix system, which can be used for the majority of strains encountered in a university-based laboratory, for ID and AST.

Fluoroquinolone resistance linked to GyrA, GyrB, and ParC mutations in Salmonella enterica typhimurium isolates in humans

We report two cases of infection with clonally unrelated, high-level ciprofloxacin-resistant, β-lactamase–producing strains of Salmonella enterica Typhimurium. Resistance was caused by four topoisomerase mutations, in GyrA, GyrB, and ParC and increased drug efflux. Ciprofloxacin treatment failed in one case. In the second case, reduced susceptibility to third-generation cephalosporins occurred after initial treatment with these drugs and may explain the treatment failure with ceftriaxone.

Salmonella enterica serovar Typhimurium bla(PER-1)-carrying plasmid pSTI1 encodes an extended-spectrum aminoglycoside 6'-N-acetyltransferase of type Ib

We have studied the aminoglycoside resistance gene, which confers high levels of resistance to both amikacin and gentamicin, that is carried by plasmid pSTI1 in the PER-1 beta-lactamase-producing strain of Salmonella enterica serovar Typhimurium previously isolated in Turkey. This gene, called aac(6')-Ib(11), was found in a class 1 integron and codes for a protein of 188 amino acids, a fusion product between the N-terminal moiety (8 amino acids) of the signal peptide of the beta-lactamase OXA-1 and the acetyltransferase. The gene lacked a plausible Shine-Dalgarno (SD) sequence and was located 45 nucleotides downstream from a small open reading frame, ORF-18, with a coding capacity of 18 amino acids and a properly spaced SD sequence likely to direct the initiation of aac(6')-Ib(11) translation. AAC(6')-Ib(11) had Leu118 and Ser119 as opposed to Gln and Leu or Gln and Ser, respectively, which were observed in all previously described enzymes of this type. We have evaluated the effect of Leu or Gln at position 118 by site-directed mutagenesis of aac(6')-Ib(11) and two other acetyltransferase gene variants, aac(6')-Ib(7) and -Ib(8), which naturally encode Gln118. Our results show that the combination of Leu118 and Ser119 confers an extended-spectrum aminoglycoside resistance, with the MICs of all aminoglycosides in clinical use, including gentamicin, being two to eight times higher for strains with Leu118 and Ser119 than for those with Gln118 and Ser119.

Evaluation of three techniques for detection of low-level methicillin-resistant Staphylococcus aureus (MRSA): a disk diffusion method with cefoxitin and moxalactam, the Vitek 2 system, and the MRSA-screen latex agglutination test

Very-low-level methicillin-resistant Staphylococcus aureus (MRSA), or class 1 MRSA, is often misdiagnosed as methicillin-susceptible S. aureus (MSSA). We evaluated the performances of three methods for detection of low-level methicillin resistance: the disk diffusion method using the cephamycin antibiotics cefoxitin and moxalactam, the Vitek 2 system (bioMérieux), and the MRSA-screen test (Denka). Detection of the mecA gene by PCR was considered to be the "gold standard." We also determined the sensitivity of the oxacillin disk diffusion method with 5- and 1-microg disks and that of the Oxascreen agar assay with 6 mg of oxacillin liter(-1) for detection of MRSA. We compared the distributions of MICs of oxacillin and cefoxitin by the E-test (AB Biodisk), and those of moxalactam by dilutions in agar, for MRSA and MSSA isolates. The 152 clinical isolates of S. aureus studied were divided into 69 MSSA (mecA-negative) and 83 MRSA (mecA-positive) isolates, including 63 heterogeneous isolates and 26 class 1 isolates (low-level resistance). The cefoxitin and moxalactam disk diffusion tests detected 100% of all the MRSA classes: cefoxitin inhibition zone diameters were <27 mm, and moxalactam inhibition zone diameters were <24 mm. The Vitek 2 system and the MRSA-screen test detected 94 and 97.6% of all MRSA isolates, respectively. The sensitivities of the 5- and 1-microg oxacillin disks were 95.2 and 96.4%, respectively, whereas that of the Oxascreen agar screen assay was 94%. All of the tests except the 1-microg oxacillin disk test were 100% specific. For the class 1 MRSA isolates, the sensitivity of the Vitek 2 test was 92.3%, whereas those of the MRSA-screen test and the disk diffusion method with cefoxitin and moxalactam were 100%. Therefore, the cefoxitin and moxalactam disk diffusion methods were the best-performing tests for routine detection of all classes of MRSA.

High prevalence of Mycoplasma genitalium in the lower genitourinary tract of women attending a sexually transmitted disease clinic in Paris, France

BACKGROUND

Previous studies have suggested that Mycoplasma genitalium is associated with cervicitis and may be a cause of pelvic inflammatory disease. This study attempted to investigate further the possible role of M genitalium in genital symptoms of women attending a sexually transmitted disease (STD) clinic.

GOAL

To determine the prevalence of and the association of clinical and microbiologic features with M genitalium in women presenting with genital symptoms.

STUDY DESIGN

Between April 1994 and June 1996 a prospective study of 170 consecutive women with abnormal vaginal discharge, with or without urethral itching, dysuria, or pelvic pain, was conducted at the STD clinic at Saint-Louis Hospital in Paris. Information was collected on each subject's characteristics, and a clinical vulvar, vaginal, and cervical examination was performed. Cervical, vaginal, and urethral samples were obtained to identify infecting organisms.

RESULTS

DNA of M genitalium was identified by polymerase chain reaction (PCR) at one or more genital sites in 65 women (38%; 95% CI, 31-46%) and was statistically more frequently detected in the vagina (39%) than in the cervix (21%) or urethra (28%) (P = 0.001 and 0.048, respectively). PCR inhibitors were detected in 17 specimens (4%). M genitalium was found in 6/14 (43%) positive for Chlamydia trachomatis, but no significant association between M genitalium and any demographic, clinical, or microbiologic data was noted in univariable or multivariable analysis.

CONCLUSION

This study indicates that M genitalium is frequently encountered in the female genital tract and is not associated with cervicitis or any particular clinical or microbiologic data.

An intrinsic control element for translational initiation in class 1 integrons

Integrons are genetic elements able to capture anti-biotic resistance and other genes and to promote their transcription. Here, we have investigated integron-dependent translation of an aminoglycoside 6'-N-acetyltransferase gene (aac(6')-Ib7) inserted at the attI1 site. N-terminal sequencing revealed that translation of this gene was initiated at a GTG codon, which is not part of a plausible translation initiation region (TIR). A short open reading frame (called ORF-11) overlapping the attI1 site was probed by site-directed mutagenesis for its contribution to aac(6')-Ib7 translation. When ORF-11 and its TIR were deleted en bloc, translational efficiency dropped by over 80%, as determined with an acetyltransferase- luciferase fusion product. Invalidation of the ATG start codon of ORF-11 or its putative Shine-Dalgarno sequence resulted in a decrease of over 60%, whereas the decrease was much less pronounced when the amino acid sequence of the putative ORF-11-encoded peptide was altered or when the distance between ORF-11 and aac(6')-Ib7 was doubled. This demonstrates that aac(6')-Ib7 translation is dependent upon the translation of ORF-11, but almost certainly not upon the corresponding peptide. These results lead us to conclude that an intrinsic short ORF present in the 5'-conserved segment of many class 1 integrons may substantially enhance expression at the translational level of captured TIR-deficient anti-biotic resistance genes.

Novel class A beta-lactamase Sed-1 from Citrobacter sedlakii: genetic diversity of beta-lactamases within the Citrobacter genus

Citrobacter sedlakii 2596, a clinical strain resistant to aminopenicillins, carboxypenicillins, and early cephalosporins such as cephalothin, but remaining susceptible to acylureidopenicillins, carbapenems, and later cephalosporins such as cefotaxime, was isolated from the bile of a patient treated with beta-lactam and quinolone antibiotics. The isolate produced an inducible class A beta-lactamase of pI 8.6, named Sed-1, which was purified. Characterized by a molecular mass of 30 kDa, Sed-1 preferentially hydrolyzed benzylpenicillin, cephalothin, and cloxacillin. The corresponding gene, bla(Sed-1), was cloned and sequenced. Its deduced amino acid sequence shared more than 60% identity with the chromosome-encoded beta-lactamases from Citrobacter koseri (formerly C. diversus) (84%), Klebsiella oxytoca (74%), Serratia fonticola (67%), and Proteus vulgaris (63%) and 71% identity with the plasmid-mediated enzyme MEN-1. A gene coding for a LysR transcriptional regulator was found upstream from bla(Sed-1). This regulator, named SedR, displayed 90% identity with the AmpR sequence of the chromosomal beta-lactamase from C. koseri and 63 and 50% identity with the AmpR sequences of P. vulgaris and Enterobacter cloacae, respectively. By using DNA-DNA hybridization, a bla(Sed-1)-like gene was identified in two reference strains, C. sedlakii (CIP-105037) and Citrobacter rodentium (CIP-104675), but not in the 18 strains of C. koseri studied. Two DNA fragments were amplified and sequenced from the reference strains of C. sedlakii CIP-105037 and C. rodentium CIP-104675 using two primers specific for bla(Sed-1). They shared 98 and 80% identity with bla(Sed-1), respectively, confirming the diversity of the chromosomally encoded class A beta-lactamases found in Citrobacter.

Antibiotic resistance in salmonellae isolated from humans and animals in France: comparative data from 1994 and 1997

Among 25526 recorded isolates of salmonellae, 5086 isolated from humans and 20440 from animals in 1994 and 1997 in France, the antibiotic resistance phenotype was determined for all human and 5336 animal isolates. In Salmonella enterica serovar typhimurium, one of the two most frequently isolated serovars from humans as well as animals, resistance to ampicillin was observed in 61% of both human and animal isolates in 1994 and in 73% of human and 53% of animal isolates in 1997. During these periods, resistance to co-amoxiclav was between 45% and 66% for both types of isolate. Resistance to ampicillin was associated with resistance to streptomycin, spectinomycin, sulphonamide, tetracycline and chloramphenicol in over 70% of isolates. Resistance to ampicillin as well as co-amoxiclav never exceeded 7% in Salmonella enteritidis. While Salmonella hadar was practically absent among the human isolates in 1994, this serovar was the third most frequent in 1997, and at that time 92% were resistant to nalidixic acid. Among the animal S. hadar isolates, the prevalence of resistance to nalidixic acid increased from 3% in 1994 to 72% in 1997. None of these isolates manifested high-level resistance to ofloxacin. The levels of resistance to aminoglycosides (< or =3%) and trimethoprim-suphamethoxazole (< or =14%) remained practically unchanged in all three serovars. The resistance markers of 463 ampicillin-resistant S. typhimurium isolated in 1997 were determined. Among the 24 phenotypes observed, six multiresistance phenotypes, representing 82% of these isolates (as compared with 80% in 1994), were associated with the PSE-1 gene typically found in the lysotype DT104 of this serovar.

In vitro activity of fusidic acid against streptococci isolated from skin and soft tissue infections

The in vitro activity of fusidic acid was evaluated against 242 strains of streptococci isolated from skin and soft tissue infections during a prospective multicentre study. Nearly 90% of strains were isolated from dermatology, emergency and medicine units. Groups A, B, C and G streptococci represented, respectively, 41.9, 20.6, 4.4 and 27.8% of the strains. The activity of fusidic acid was dependent on the media used. MICs were generally one dilution lower with heart infusion agar than with Mueller-Hinton agar supplemented with 5% horse blood (MIC(90) for the whole streptococcal population = 8 mg/L and 16 mg/L, respectively). The distribution of MICs was unimodal and only two strains displayed MICs of fusidic acid >/= 64 mg/L. In both media, fusidic acid was moderately active against streptococci. However, antibiotic concentrations obtained in the skin exceed the MIC(90) of fusidic acid for streptococci, possibly explaining its clinical efficacy in the treatment of common cutaneous infections.

Multidrug-resistant human and animal Salmonella typhimurium isolates in France belong predominantly to a DT104 clone with the chromosome- and integron-encoded beta-lactamase PSE-1

Epidemiologic relationships were investigated in 187 ampicillin-resistant Salmonella typhimurium strains (86 human, 101 animal) from >2000 strains isolated in 1994. Of 23 resistance patterns, the most frequent (ampicillin [Am], chloramphenicol [Cm], tetracycline [Tc], streptomycin and spectinomycin [Sm], and sulfonamides [Su]) was found in 69.5% of human and 64.8% of animal isolates. Four beta-lactamase genes were identified, blaTEM (24%), blaPSE-1 (78%), and blaSHV and oxa-2 (each <3%). blaPSE-1 and the integrase gene, intI1, but not blaTEM, blaSHV or oxa-2, were chromosomeborne and found almost exclusively in the AmCmTcSmSu strains. In these, polymerase chain reaction mapping revealed two distinct integrons carrying blaPSE-1 or aadA2. Lysotypes, plasmid profiles, and restriction fragment length polymorphisms (IS200) were determined for 50 representative isolates and for 3 DT104 strains from the United Kingdom (UK). The phage type of the PSE-1-producing AmCmTcSmSu strains was 12 atypic, indistinguishable from that of the DT104 strains. The combined data indicate that the same multiresistant clone has spread through human and animal ecosystems in the UK and France.

Novel OXA-10-derived extended-spectrum beta-lactamases selected in vivo or in vitro

A clinical isolate of Pseudomonas aeruginosa, PAe191, was found to be highly resistant to all anti-Pseudomonas beta-lactam antibiotics (except imipenem) and resistant also to aminoglycosides. It produced a beta-lactamase (with an apparent pI of 7.6) which was not inhibited by clavulanic acid. Cloning and characterization of the beta-lactamase gene showed that it coded for a novel extended-spectrum OXA-10 variant, called OXA-19, which differed from OXA-10 by nine amino acids and from OXA-13 by two, i.e., Asn in position 73 (Asn73) instead of Ser and Asp157 instead of Gly. Asparagine in position 157 is implicated in resistance to ceftazidime, while the amino acid in position 73, in this variant, seems to condition the level of resistance to penicillins. The oxa19 gene was found to be inserted, in a typical integron structure, immediately downstream from an aac(6')-Ib gene coding for an aminoglycoside acetyltransferase variant, which was called AAC(6')-Ib9.

Aminoglycoside 6'-N-acetyltransferase variants of the Ib type with altered substrate profile in clinical isolates of Enterobacter cloacae and Citrobacter freundii

Three clinical isolates, Enterobacter cloacae EC1562 and EC1563 and Citrobacter freundii CFr564, displayed an aminoglycoside resistance profile evocative of low-level 6'-N acetyltransferase type II [AAC(6')-II] production, which conferred reduced susceptibility to gentamicin but not to amikacin or isepamicin. Aminoglycoside acetyltransferase assays suggested the synthesis in the three strains of an AAC(6') which acetylated amikacin practically as well as it acetylated gentamicin in vitro. Both compounds, however, as well as isepamicin, retained good bactericidal activity against the three strains. The aac genes were borne by conjugative plasmids (pLMM562 and pLMM564 of ca. 100 kb and pLMM563 of ca. 20 kb). By PCR mapping and nucleotide sequence analysis, an aac(6')-Ib gene was found in each strain upstream of an ant(3")-I gene in a sulI-type integron. The size of the AAC(6')-Ib variant encoded by pLMM562 and pLMM564, AAC(6')-Ib7, was deduced to be 184 (or 177) amino acids long, whereas in pLMM563 a 21-bp duplication allowing the recruitment of a start codon resulted in the translation of a variant, AAC(6')-Ib8, of 196 amino acids, in agreement with size estimates obtained by Western blot analysis. Both variants had at position 119 a serine instead of the leucine typical for the AAC(6')-Ib variants conferring resistance to amikacin. By using methods that predict the secondary structure, these two amino acids appear to condition an alpha-helical structure within a putative aminoglycoside binding domain of AAC(6')-Ib variants.

Sternal abscess due to Bartonella (Rochalimaea) henselae in a renal transplant patient

Bartonella henselae, previously called Rochalimaea henselae, is the causative agent of cat scratch disease (CSD) in immunocompetent subjects and bacillary angiomatosis in immunocompromised ones. Bone lesions are common in bacillary angiomatosis, but not in CSD. We present the case of a patient with a renal transplant treated by immunosuppressive therapy who developed a sternal abscess with a histological pattern of CSD. The CT pattern was that of a lytic bone lesion with adjacent fluid collection. The diagnosis was made on the basis of a polymerase chain reaction amplification performed on bone material. Bartonella henselae is a newly described bacteria that causes CSD in a normal host and bacillary angiomatosis in immunocompromised patients. We report a case of an osteolytic lesions of the sternum with adjacent fluid collection related to CSD, which occurred in a patient with a renal transplant.

Prevalence of and risk factors for Clostridium difficile colonization at admission to an infectious diseases ward

A study of 240 consecutive admissions to a single hospital ward over a 6-month period was conducted to determine the prevalence of and risk factors for Clostridium difficile colonization at admission. The prevalence rate of C. difficile colonization at admission was 13.3%. Seventy-four percent of the patients admitted to the ward were infected with human immunodeficiency virus (HIV). Multivariate analysis identified three risk factors for C. difficile colonization: clindamycin use (adjusted odds ratio [OR], 9.4; P < .001), penicillin use (adjusted OR, 3.9; P = .018), and a history of cytomegalovirus infection (adjusted OR, 4.2; P = .02). C. difficile colonization at admission to our infectious diseases ward was common. Antibiotic treatments received before admission were the main risk factors for C. difficile colonization. HIV infection per se was not associated with C. difficile colonization. It is interesting that there was an association between C. difficile colonization and a history of cytomegalovirus infection.

Balanitis and balanoposthitis: a review

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A TEM-derived extended-spectrum beta-lactamase in Pseudomonas aeruginosa

A clinical strain of Pseudomonas aeruginosa, PAe1100, was found to be resistant to all antipseudomonal beta-lactam antibiotics and to aminoglycosides, including gentamicin, amikacin, and isepamicin. PAe1100 produced two beta-lactamases, TEM-2 (pI 5.6) and a novel, TEM-derived extended-spectrum beta-lactamase called TEM-42 (pI 5.8), susceptible to inhibition by clavulanate, sulbactam, and tazobactam. Both enzymes, as well as the aminoglycoside resistance which resulted from AAC(3)-IIa and AAC(6')-I production, were encoded by an 18-kb nonconjugative plasmid, pLRM1, that could be transferred to Escherichia coli by transformation. The gene coding for TEM-42 had four mutations that led to as many amino acid substitutions with respect to TEM-2: Val for Ala at position 42 (Ala42), Ser for Gly238, Lys for Glu240, and Met for Thr265 (Ambler numbering). The double mutation Ser for Gly238 and Lys for Glu240, which has so far only been described in SHV-type but not TEM-type enzymes, conferred concomitant high-level resistance to cefotaxime and ceftazidime. The novel, TEM-derived extended-spectrum beta-lactamase appears to be the first of its class to be described in P. aeruginosa.

Antimicrobial resistance and epidemiological study of Haemophilus influenzae strains isolated in Portugal. The Multicentre Study Group

In the course of a multicentric surveillance study, nine laboratories sent 375 isolates of Haemophilus influenzae to the Sector de Resistência aos Antibióticos (SRA) from the National Institute of Health in Lisbon, between 1 January and 31 December 1992. The majority of the H. influenzae isolates were from the respiratory tract (84.8%); only 5.1% were of invasive origin. Overall resistance for ampicillin was 11.7%, tetracycline 3.7%, and chloramphenicol 2.4%. All isolates tested were fully susceptible to cefotaxime, ceftriaxone, ciprofloxacin and rifampicin. Multiresistance was rare, occurring only in 2.4% of the isolates, although 50% of the ampicillin resistant strains had at least one additional resistance marker. Forty two isolates (11.2%) produced a TEM-1 type beta-lactamase, as shown by isoelectric focusing. beta-lactamase production was not detected in two of the ampicillin resistant strains. Fifteen of the 42 beta-lactamase producing strains (35.7%) contained detectable DNA plasmid: nine harboured large plasmids with an apparent molecular mass of 45 or 54 kb depending on their resistance phenotype and six harboured a small plasmid of 5 kb. In order to study transfer of resistance in both ampicillin and multiresistant strains conjugation experiments were performed for 14 isolates, seven of which harboured a large plasmid and seven had no detectable plasmid DNA. All 14 transferred their resistance phenotype but only a single large plasmid could be demonstrated in ten transconjugants. Restriction endonuclease analysis of plasmids from six representative transconjugants, isolated in different hospitals, revealed that there was no dissemination of a single R plasmid, which suggests an independent process of acquisition of resistance genes.

[Sexually transmitted diseases in men]

Sexually transmitted diseases (STD) constitute a frequent presenting complaint. The epidemiology of human immunodeficiency virus (HIV) infection is identical to that of STD and must therefore be systematically investigated in the presence of any STD. Chlamydia trachomatis (CT) is involved in the majority of cases of urethritis and epididymitis in young subjects and is present in the urethra of 10% of subjects with a genital ulcer. Genital ulcers are due to either Treponema Pallidum, Haemophilus ducreyi, or Herpes simplex virus: there is little clinicobacteriological correlation and it is therefore essential to perform laboratory examinations in order to establish the diagnosis. The prevalence of venereal vegetations due to HPV viruses has increased markedly over recent years and require effective treatment and surveillance because of the risk of carcinoma induced by viral oncogenesis. Other viral diseases such as hepatitis B are also classified as STD. The main diagnostic techniques used at the present time for each STD are reviewed and the consensually accepted therapeutic protocols are also proposed.

Genotypic identification of two groups within the species Bacteroides fragilis by ribotyping and by analysis of PCR-generated fragment patterns and insertion sequence content

Molecular typing allowed the separation of the species Bacteroides fragilis into two genotypically distinct groups. A unique set of 50 strains of B. fragilis carrying the chromosomal metallo-beta-lactamase gene cfiA was subjected to a comparative analysis with respect to sets of up to 250 randomly collected strains devoid of this gene. The two groups were found to be distinct on the basis of the following results: (i) ribotyping, after DNA digestion with AvaI, revealed a practically homogeneous DNA fragment pattern for the cfiA-positive strains and distinct multiple patterns for the cfiA-negative strains; (ii) PCR, arbitrarily primed with an experimentally selected decamer, generated fragment patterns typical for the strains of each group; (iii) the three insertion sequences described to date in the species B. fragilis, i.e., IS4351, IS942, and IS1186, were all but confined to the cfiA-positive group, in which they were capable of providing promoter sequences for the transcription of cfiA; and (iv) the cepA gene, encoding the so-called endogenous cephalosporinase of B. fragilis, was found exclusively in the cfiA-negative group, in which it was present in ca. 70% of the strains. The cfiA-, cepA-negative fraction was not characterized further. In a natural population of 500 randomly selected strains of B. fragilis, the cfiA-positive and cfiA-negative groups represented ca. 3 and 97% of the strains, respectively. Analysis of 82 metabolic traits revealed no difference between the two groups.

Campylobacter infections in HIV-infected patients: clinical and bacteriological features

OBJECTIVE

To study the clinical and bacteriological features of Campylobacter infections in HIV-infected patients.

DESIGN

A retrospective analysis (1989-1992), followed by a prospective analysis (1992-1994).

SETTING

Hospital HIV inpatient unit.

PATIENTS AND METHODS

All patients with Campylobacter spp. identified by the laboratory of microbiology at Saint-Louis Hospital, Paris were studied, and their clinical features as well as their response to therapy recorded.

RESULTS

During the study period, Campylobacter infection was documented in 38 HIV-infected patients, 76% of whom had AIDS. Campylobacter spp. was isolated from stools in 36 cases and from blood cultures in four cases. Species identification yielded C. jejuni (84%) and C. coli (16%). High-level resistance to quinolones was frequently observed (21%), but resistance to erythromycin (3%) and tetracycline (5%) was rare. Diarrhoea, fever and abdominal pain were the main clinical features of infection. Other intestinal pathogens were found in 42% of patients. Most patients had an acute illness with rapid resolution under appropriate antimicrobial therapy. However, eight patients (21%), experienced chronic diarrhoea with persistent isolation of Campylobacter and in vivo selection of resistant strains, requiring multiple courses of antibiotics.

CONCLUSIONS

Campylobacter usually cause acute diarrhoea in patients with HIV infection. Antimicrobial therapy should be guided on in vitro susceptibility testing because of the prevalence of antibiotic resistance. Despite appropriate therapy, some patients will present with prolonged diarrhoea and in vivo selection of multiresistant isolates.

Male urethritis with and without discharge: a clinical and microbiological study

BACKGROUND

The definition of male urethritis in the absence of urethral discharge has not been well established. The sensitivity of urethral swabs and first-catch urine is controversial.

GOAL OF THIS STUDY

To correlate clinical data (discharge or not), urethral swabs, and first-catch urine examinations with the microorganisms found within the urethra in a cohort of men attending the sexually transmitted disease clinic of Hôpital Saint Louis (Paris) for treatment of urethral symptoms with or without discharge.

STUDY DESIGN

Two-hundred-seventy-three consecutive male patients entered this prospective study between October 1, 1992 and November 30, 1992. Fifty-two patients were excluded because they had been treated with antibiotics in the previous 3 months. All patients were screened for Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Trichomonas vaginalis, Ureaplasma urealyticum, Mycoplasma hominis, and Candida albicans.

RESULTS

Two-hundred-nineteen patients were eligible for the study (122 with discharge and 97 with no discharge). The prevalence of microorganisms was as follows: Chlamydia trachomatis in 13%, Neisseria gonorrhoeae in 11%, Ureaplasma urealyticum in 7%, Mycoplasma genitalium in 17%, Trichomonas vaginalis in 1%, and indeterminate pathogens alone in 20%. All major pathogens and Mycoplasma genitalium were more common in patients with discharge. Stratification of results according to the presence of polymorphonuclear leukocytes on the urethral swab and first-catch urine showed a low sensitivity of both tests for Chlamydia trachomatis (29%), Mycoplasma genitalium (50% and 62%), and Ureaplasma urealyticum (33%) in patients with no discharge.

CONCLUSION

A specific and sensitive search for Chlamydia trachomatis should be done in every patient with urethral symptoms whether or not the classic symptoms of urethritis are present (discharge, presence of polymorphonuclear leukocytes in the urethra or first-catch urine).

Molecular epidemiology of Klebsiella pneumoniae strains that produce SHV-4 beta-lactamase and which were isolated in 14 French hospitals

Preliminary results suggested that the diffusion in France of the SHV-4 extended-spectrum beta-lactamase was probably due to the spread of one single epidemic strain of Klebsiella pneumoniae. In this study, we tested various phenotypic and genotypic markers to compare K. pneumoniae strains producing this enzyme isolated in 14 French hospitals between 1987 and 1989. All of the strains were of the same capsule serotype, K25. Twelve of them were of the same biotype: weak urease activity and no sucrose fermentation. Among the six plasmid profiles observed, one accounted for eight strains. Large plasmids of 170 kb encoding SHV-4 beta-lactamase were present in all strains of K. pneumoniae and could be transferred by conjugation with high frequency to Escherichia coli J53-2 or HB101 from all except one strain. Plasmid EcoRI restriction patterns suggested that these plasmids were closely related and similar to pUD18 encoding SHV-3 beta-lactamase, originally described in France and differing from SHV-4 by one amino acid substitution. Ribotyping with EcoRI and HindIII and genomic fingerprinting with XbaI by pulsed-field gel electrophoresis were concordant and suggested that 12 of the isolates recovered from the 14 hospitals were probably the same strain. Dissemination in France of the SHV-4 extended-spectrum beta-lactamase was thus essentially due to the diffusion of a single K. pneumoniae clone.

[Beta-lactamase-producing Haemophilus influenzae isolated in Portugal, 1989-1992]

Within the framework of a national multicentric study between 1989 and 1992, 118 strains of betalactamase producing Haemophilus influenzae were isolated. Biotyping demonstrated the predominance of biotypes I, II and III, with 22, 36 and 24% of the strains, respectively. Encapsulated strains accounted for 13% of the total; all, but one, were serotype b. The antimicrobial susceptibility test (dilution method) of the 118 ampicillin--resistant strains showed: 33.9% resistance to tetracycline, 29.7% to chloramphenicol, 10.2% to erythromycin, 9.3% to trimethoprim, 0.8% to rifampicin, and 29.7% of multiresistance. All strains were susceptible to augmentin, cefotaxime, ceftriaxone and ceprofloxacin. Ninety strains were screened for resistant plasmids. A large plasmid (30-50 Mdal) was isolated in 38.9% of the strains and a small plasmid (3-4.4 Mdal) in 10%. No plasmid was found in 51% of the strains. Isoelectric focusing of 54 beta-lactamases showed that all were type TEM-1 (pI = 5.4), with the exception of one, which was type TEM-2 (pI = 5.6).

Risk factors for Clostridium difficile-associated diarrhoea in HIV-infected patients

OBJECTIVE

To identify risk factors associated with a first episode of Clostridium difficile-associated diarrhoea (CDAD) in patients with HIV infection.

DESIGN

A case-control study.

SETTING

University teaching hospital HIV inpatient unit.

PATIENTS AND METHODS

Nineteen HIV-infected patients with CDAD, defined as diarrhoea with positive stool culture for Clostridium difficile (CD) and positive stool cytotoxin B assay, were compared with 38 randomly selected controls (HIV-infected patients hospitalized on the ward on the day the matched case was diagnosed). CD isolates were phenotyped by electrophoretic protein patterns.

RESULTS

The incidence of CDAD among HIV-infected patients was 4.1/100 of patient-admissions. On univariate analysis, cases were more likely to have used clindamycin [11 out of 19 compared with four out of 38; odds ratio (OR) 19; 95% confidence interval (CI), 2-160; P = 0.0007], and pyrimethamine (14 out of 19 compared with 13 out of 38; OR, 4.8; 95% CI, 1.4-16, P = 0.02) in the month before diagnosis, and to have had cerebral toxoplasmosis (12 out of 19 compared with 13 out of 38; OR, 2.8; 95% CI, 0.9-8.6; P = 0.09). There was also a significant increase of the risk of CDAD as duration of hospitalization in the ward increased (chi 2 for trend, P = 0.007). Multivariate models associated two risk factors with CDAD: clindamycin use (OR, 42; 95% CI, 2-813; P = 0.01), and prolonged hospitalization in the ward (OR, 3.6 per week in the ward; 95% CI, 1-13, P = 0.048). Of 18 available CD isolates, 15 (83%) had identical electrophoretic protein pattern.

CONCLUSIONS

Clindamycin use and prolonged hospitalization in the ward were the main risk factors associated with CDAD in this study. These observations, together with the occurrence of one major phenotype of CD, suggest nosocomial transmission of CD in the ward.

Intestinal microsporidiosis in human immunodeficiency virus-infected patients with chronic unexplained diarrhea: prevalence and clinical and biologic features

Eighteen patients infected with human immunodeficiency virus and with chronic unexplained diarrhea were prospectively studied to investigate the prevalence and clinical and biologic features of intestinal microsporidiosis. All patients underwent extensive evaluation for bacterial, viral, and parasitic pathogens. Enterocytozoon bieneusi was found in 9 patients (50%; 95% confidence interval, 27-73) in stools and duodenal and jejunal biopsies. In 8 patients, it was the sole pathogen found. Other pathogens were also isolated from the intestinal tracts of 4 patients, but diarrhea remained unexplained in 6. Patients with intestinal microsporidiosis had significantly lower mean Karnofsky scores (69.4 vs. 85.5, P = .009), CD4 cell counts (18.6 vs. 209.8/microL, P = .02), and D-xylose absorption tests (0.13 vs. 0.36 g/L, P < .001) than did patients without intestinal microsporidiosis. Intestinal microsporidiosis appears to be a frequent cause of unexplained chronic diarrhea in patients with AIDS and is associated with diminished D-xylose absorption.

[Microbiological study of male genital ulcers. Apropos of 75 cases]

Between November 1986 and June 1987, the microbial aetiology of genital ulcers was assessed in 75 male patients attending the Sexually Transmitted Disease (STD) clinic in Hôpital Saint-Louis, Paris. Evidence of Haemophilus ducreyi was found in 18 patients (24%), Herpes simplex virus in 19 (25.3%). Syphilis was diagnosed on the basis of dark field microscopy and/or positive serology test in 19 patients (25.3%). Lymphogranuloma venereum was not diagnosed in any patient. Primary pathogens were not identified from the remaining 19 (25.3%) men. Neisseria gonorrhoea was isolated in five patients, from the ulcer in three cases, from the urethra in two. Asymptomatic urethral carriage of Chlamydia trachomatis was culture proven in seven cases. The presence of IgM antibodies to C. trachomatis at a titre greater than 40 found in 17 patients was a indication of a current chlamydial infection. Three patients (4%) were discovered to be HIV-1 positive.

Lymphogranuloma venereum: 27 cases in Paris

Twenty-seven men with laboratory-confirmed lymphogranuloma venereum (LGV) were identified among 211 patients tested for LGV or chancroid during a 6-y period. The patients with LGV ranged in age from 17 to 73 y; most were from countries other than France. Twenty-five sought care because of inguinal adenopathy (with spontaneous draining fistulae in two patients) and two because of proctitis. Chlamydia trachomatis was isolated from nine patients; all isolates were the LGV biovar as demonstrated by biologic characterization and monoclonal antibody reactivity. In patients without isolation of C. trachomatis, the diagnosis was based on chlamydial complement fixation antibody titers greater than or equal to 1:32 (mean titer, 1:128). Genital herpes was an associated diagnosis in one patient and syphilis in two patients. Serologic evidence of exposure to human immunodeficiency virus (HIV) type 1 was present in five patients and to HIV-2 in one patient.

Serum antibody response to the 70,000-molecular-weight neisserial common antigen in humans infected by Neisseria gonorrhoeae

We evaluated the presence of antibodies directed against a 70,000-molecular-weight (70K) common neisserial antigen in sera from patients with first or repeated gonococcal infections and in sera from healthy controls. Sera were taken as soon as possible after the onset of disease, and anti-70K antibodies were detected by Western blot (immunoblot). Results show that significantly fewer patients with gonococcal infection possessed anti-70K antibodies than controls (P less than 0.001). This suggests a possible role of anti-70K antibodies in natural immunity against Neisseria gonorrhoeae.

Rapid determination of MICs of 15 antichlamydial agents by using an enzyme immunoassay (Chlamydiazyme)

An enzyme immunoassay (EIA), Chlamydiazyme (Abbott Laboratories), was evaluated for its determination of MICs of 15 antimicrobial agents against Chlamydia trachomatis (MRC-1, LB, TRIC/GB/MRC-1 Gf [ATCC VR-1]). The inoculum size, incubation time, and enhancers were defined for the assessment of chlamydial antigen synthesis in HeLa 229 cells seeded as monolayers in 96-well plates. MICs were determined and defined as the lowest antibiotic concentrations required to inhibit, after 24 or 48 h of incubation, antigen production as determined by the EIA. The MICs (after 48 h) were similar to those determined by the peroxidase-antiperoxidase staining of inclusions. MIC determinations after 24 h were suitable for screening the activities of quinolones, but less so for measuring the susceptibility of C. trachomatis to macrolides and tetracyclines. MIC determination by EIA was rapid, appropriate for standardization, and less cumbersome than determination by quantification of inclusions.

rRNA gene restriction patterns of Haemophilus influenzae biogroup aegyptius strains associated with Brazilian purpuric fever

The rRNA gene restriction patterns of 92 isolates of Haemophilus influenzae biogroup aegyptius, associated with conjunctivitis or Brazilian purpuric fever in the State of São Paulo, Brazil, were studied with 16 + 23S rRNA from Escherichia coli as a probe. All strains were classified into 15 patterns. Isolates from Brazilian purpuric fever cases were seen only in patterns 3 (most frequently) and 4 (rarely), whereas isolates from conjunctivitis were found in all 15 patterns. The study demonstrated that rRNA from E. coli can serve as a probe for molecular epidemiology.

Biotypes, serotypes, and susceptibility to antibiotics of 60 Haemophilus influenzae strains from genitourinary tracts

Sixty strains of Haemophilus influenzae were isolated from the genitourinary tracts of adults: 19 from cervicovaginal secretions, one from a woman with bartholinitis, 37 from urethral exudates, and three from urine. Non-capsulated strains were recovered predominantly, and biotype III accounted for 28 isolates and biotype IV for 25. Many of the H influenzae strains were found to be resistant to one or more of the antibiotics commonly used against sexually transmitted diseases. Resistance to tetracycline was prevalent and was found in 17 of the strains. Ten strains were ampicillin resistant and beta lactamase producing. Kanamycin resistance was less common (two strains). Trospectomycin (U-63366), a new spectinomycin analogue, was eight to 16 times more active than spectinomycin. All the quinolones tested were very active against all strains and may provide an effective alternative for the treatment of resistant H influenzae in genitourinary infections.

Sexual behavior and smoking: risk factor for urethritis in men

Two hundred men who had symptoms of urethritis and 207 controls were interviewed. Because 60% of the men were of foreign nationality, the analysis of risk factors for urethritis was undertaken separately for the French and foreign subpopulations. The risk factors for urethritis were different for the French and foreign men. For the French men who had smoked, the risk of infection was 2.9 times greater than that for men who had never smoked (95% confidence interval, 1.2-7.6), after taking type of sexual behavior into account. There is a significant increase in the risk of urethritis when the amount of tobacco consumed daily increases (P less than 0.02). This finding suggests that smoking is an independent risk factor.

[Characteristics of penicillinase-producing strains of Neisseria gonorrhoeae isolated in France, 1979-1986]

Penicillinase producing Neisseria gonorrhoeae PPNG, had been first isolated in France in 1979. Since, they regularly increased if we considered France on the whole. From 1979 to 1986, 284 strains had been collected by a multicentric group. The frequency of isolation was strongly different in France, unknown in some region they rose 12% in specific areas in Paris. The PPNG strains were more frequently isolated from male than female (sex ratio was higher with PPNG than for non producing strain). They were more often responsible of complicated infections in female than male at the same rate than the non producing strains. Auxotype distribution was different between producing and non producing strains. Plasmidic content from african type (Af) was almost the same than from asian type (As). Strains with Af type associated with the conjugative plasmid were increasing.