Klebsiella pneumoniae CTX-M-15 : vers une modification de l’épidémiologie des ß-lactamases à spectre étendu

Klebsiella pneumoniae is frequently involved in nosocomial outbreaks worldwide. High level of resistance is common for these bacteria leading to reduce antibiotic treatments and prolonged hospital stay for patients. Resistance determinants are often located on plasmids. During the 1980-1990s, ESBL encoding genes belonged to the TEM and SHV type. From the early 2000s, a new trend was observed with ESBL of the CTX-M type being increasingly described in K. pneumoniae, and more particularly CTX-M-15.     

Characteristics of Enterobacter cloacae prosthetic joint infections

ObjectivesEnterobacter cloacae prosthetic joint infections (PJI) are rare and poorly documented.Patients and methodsWe conducted a retrospective and monocentric study in an orthopedic unit supporting complex bone and joint infections. Between 2012 and 2016 we collected background, clinical, biological, and microbiological data from 20 patients presenting with prosthetic joint infection and positive for E. cloacae, as well as data on their surgical and medical treatment and outcome.ResultsInfections were localized in the hip (n = 14), knee (n = 5), or ankle (n = 1). The median time between arthroplasty and septic revision was three years. Fourteen patients (70%) had undergone at least two surgeries due to previous prosthetic joint infections. The median time between the last surgery and the revision for E. cloacae infection was 31 days. Eleven patients (55%) were infected with ESBL-producing strains. The most frequently used antibiotics were carbapenems (n = 9), cefepime (n = 7), quinolones (n = 7), and fosfomycin (n = 4). The infection was cured in 15 patients (78.9%) after a 24-month follow-up. Five patients had a recurrent infection with another microorganism and four patients had a relapse of E. cloacae infection. The global success rate was 52.7% (58.3% for DAIR and 75% for DAIR + ciprofloxacin).ConclusionProsthetic joint infections due to E. cloacae usually occur early after the last prosthetic surgery, typically in patients with complex surgical and medical histories. The success rate seems to be increased when DAIR is associated with ciprofloxacin.     

Faecal carriage of extended‐spectrum β‐lactamase‐producing Enterobacteriaceae among humans in Java,Indonesia, in 2001–2002

Objective To characterise commensal Escherichia coli and other Enterobacteriaceae with reduced susceptibility to cefotaxime that were collected in a large survey carried out among 3995 patients and healthy persons in two urban regions on Java, Indonesia, in 2001–2002. Methods The putative extended‐spectrum β‐lactamase (ESBL)‐producing Enterobacteriaceae were analysed using double‐disk synergy tests, isoelectric focusing, PCR assays, DNA sequencing, and pulsed‐field gel electrophoresis (PFGE). Results On the day of discharge after five or more days of hospitalisation, at least 95 of 999 (9.5%) patients carried ESBL‐positive Enterobacteriaceae as dominant faecal flora. Six patients were simultaneously colonised with E. coli and Klebsiella pneumoniae isolates with ESBL activity. On admission, only 6 of 998 (0.6%) patients were colonised. Faecal carriage of ESBL‐producing Enterobacteriaceae among healthy persons or persons visiting a public health centre was not detected. The 107 ESBL‐positive strains included 68 E. coli, 35 K. pneumoniae, and four other Enterobacteriaceae. bla_CTX‐M‐15 was the most prevalent ESBL in both E. coli (47.1%) and K. pneumoniae (45.7%), but the E. coli O25b‐ST131 clone was virtually absent. Other ESBL types found were: SHV‐2, ‐2a, ‐5, ‐12, CTX‐M‐3, ‐9, ‐14, and TEM‐19. PFGE revealed extensive genetic diversity among the isolates. Conclusions In 2001–2002, faecal carriage of ESBL‐producing Enterobacteriaceae as dominant flora in Indonesia was almost exclusively hospital‐associated. The presence of various bla_ESBL genes and the extensive genetic diversity among isolates argue against a single/dominant strain outbreak.     

Travel and acquisition of multidrug-resistant Enterobacteriaceae

Bacterial resistance to antibiotics is considered a major threat to health. Enterobacteriaceae have increasingly become resistant to antibiotics through the acquisition and dissemination of extended-spectrum beta-lactamases (ESBL) that confer resistance to most beta-lactams. While ESBL-producing Enterobacteriaceae were formerly restricted to hospitals, they have now spread to community settings, especially in developing countries. The tremendous expansion of international travels contributed to the importation of multidrug-resistant Enterobacteriaceae (MRE) to low prevalence countries. Several studies reported that 21 to 51% of healthy travelers acquire a MRE when travelling abroad, depending on the visited region (Asia, and especially South Asia being associated with the highest risk – up to 85%). Traveling to Africa or the Middle East is associated with lower but still disturbing rates (13–44%). In addition, the occurrence of digestive disorders and/or diarrhea and antibiotic intake increase the risk of MRE acquisition by 2–3 folds. After traveling though, the length of MRE carriage seems to be short (< 1 month) and the risk of transmission within the household appears to be low. Nonetheless and beyond the intestinal carriage of MRE, traveling to endemic areas has also been pointed as a risk factor for infections involving MRE, mainly urinary tract infections.     

Characterization of resistance genes in 68 ESBL-producing Klebsiella pneumonia in Lebanon

AimWe studied 68 ESBL-producing Klebsiella pneumoniae strains isolated in Lebanon, determined their profile of resistance to antibiotics, and identified 6 ESBL genes.MethodologyThe susceptibility to antibiotics was determined by the disk diffusion method. The MIC of carbapenems and cefepime was determined by the agar dilution method. ESBL genes were detected by PCR.ResultsA percentage of 88.2% and 86.7% of isolates carried the SHV and CTX-M gene respectively; combinations of more than 1 gene of resistance were detected in several isolates. Five strains were resistant to carbapenems; 4/5 carried the OXA-48 gene.ConclusionOur study revealed the emergence of K. pneumoniae ESBL (+) strains carrying several types of genes involved in this phenotype; we also identified carbapenem-resistant strains due to the OXA-48 gene, which are a real threat for public health, especially in Lebanon.     

Résistance aux quinolones de types qnr, aac (6′)-Ib-cr chez les entérobactéries isolées à Annaba en Algérie

Aim of the study

To show the emergence of the qnr and aac (6′)-Ib-cr genes in nalidixic acid resistant enterobacteria isolated at Annaba city in Algeria.

Materials and methods

Enterobacterial strains (n = 25) resistant to nalidixic acid have been isolated at the microbiology laboratory of the Annaba city hospital in Algeria Antibiotic susceptibility (disc diffusion method and MIC) and screening for Extended Spectrum Beta-Lactamase (ESBL) were performed according to the French Society for Microbiology guidelines. Characterization of quinolone resistance genes (qnrA, qnrB, qnrS, aac(6′)-Ib-cr) was investigated by PCR. Identification of ESBL (TEM, SHV, CTX-M1, CTX-M2, CTX-M8 and CTX-M9 groups) was performed by PCR. Identification of plasmid AmpC beta-lactamases was performed by multiplex PCR. All PCR products were sequenced on both strands. Conjugation experiments were performed using azide-resistant Escherichia coli K₁₂J₅ as a recipient strain.

Results

Among the 25 strains selected, 24 were resistant to at least four antibiotics. Six strains showed an ESBL phenotype. The qnr gene (B1 type) was found in two ESBL producing strains with at least two types of bla gene. The aac (6′)-Ib gene was detected in three strains, one with the aac (6′) Ib-cr variant. With specific primers, we have shown that qnrB1, CTX-M-28, TEM1, aac (6′)-Ib-cr was cotransferred together and that these genes are carried by conjugative plasmids of high molecular weight.

Conclusion

The emergence of combination of resistance genes may pose a public health problem. Thus, a policy of surveillance of resistance seems necessary.     

Emergence of SHV-12 extended spectrum beta-lactamase among clinical isolates of Enterobacter cloacae in Tunisia

A collection of seven multidrug-resistant clinical isolates of Enterobacter cloacae with reduced susceptibility to ceftazidime and cefepime recovered from 2009 to 2010 at the University Hospital of Mahdia, Tunisia, was analysed. PCR analysis and sequencing demonstrated that all study isolates harbored SHV-12 β-lactamase that was transferred by conjugation. Characterization of the regions surrounding the bla_SHV-12 showed that this gene was ?anked by two IS26 elements. pulsed-field gel electrophoresis (PFGE) revealed differents profiles indicating that the study isolates were not clonally related. Diffusion of E. cloacae producing SHV-12 ESBL in our hospital is the consequence of disseminations of plasmids harboring the SHV-12 gene.