Outbreak of SHV-5 β-Lactamase-ProducingKlebsiella pneumoniaein a Neonatal-Pediatric Intensive Care Unit in Spain

Gut acquisition of Extended-spectrum β-lactamases-producing Klebsiella pneumoniae in preterm neonates: Critical role of enteral feeding, and endotracheal tubes in the neonatal intensive care unit (NICU)

BACKGROUND

Klebsiella spp. can colonize the intestine of preterm neonates, and over-growth has been associated with necrotizing enterocolitis, hospital-acquired infections, and late-onset sepsis. This could lead us to suggest that the clinical pertinence of intestinal colonization with ESBL in preterm neonates appears to be important. We conducted this study to characterize the genetic proprieties of ESBL-producing Klebsiella pneumoniae (ESBL-KP) under clinical isolates and to describe the risk factors for the intestinal tract acquisition event during hospitalization.

METHODS

One hundred and thirteen premature infants were recruited from the neonatal intensive care unit (NICU). All newborns are issued from the birth suites of the pregnancy department. Two rectal swabs were planned to define K. Pneumoniae intestinal carriage status. ESBL-KP was confirmed by Brilliance ESBL selective chromogenic Agar. Antimicrobial susceptibility testing including phenotypic testing and genotypic detection of the most commonly described ESBL genes was done. Logistic regression models were performed to find the variables associated with the acquisition event of ESBL-KP.

RESULTS

A total of 62 (54.86%) premature neonates were colonized with ESBL-KP. The rate of blaSHV, blaTEM, blaCTX-M1, blaCTX-M2, blaCTX-M9, and blaOXA-48 genes among the isolates was 82, 48, 93.5, 4.8, 11.2 and 3.22%, respectively. We found that ESBLs K. Pneumoniae isolates were 100% resistant to amoxicillin, clavulanic acid-amoxicillin, cefotaxime, ceftazidime, and gentamicin. The regression model is for a given significant association between the tract intestinal of ESBL-KP acquisition events and the use of enteral tube feeding (OR = 38.46, 95% CI: 7.86-188.20, p-Value: 0.001), and endotracheal tubes (OR = 4.86, 95% CI: 1.37-17.19, p-Value 0.014).

CONCLUSION

Our finding supposes that the enteral feeding tube and endotracheal tube might have a critical role in colonizing the intestinal tract of preterm infants. This highlights the current status of both practices that will require updated procedures in the NICU.

Identification and molecular characterization of Escherichia coli blaSHV genes in a Chinese teaching hospital

Escherichia coli (E. coli) commonly reside in human intestine and most E. coli strains are harmless, but some serotypes cause serious food poisoning. This study identified and molecularly characterized bla_SHV genes from 490 E. coli strains with multi-drug resistance in a hospital population. PCR and molecular cloning and southern blot were performed to assess functions and localizations of this resistant E. coli gene and the pulsed-field gel electrophoresis (PFGE) was utilized to demonstrate the clonal relatedness of the positive E. coli strains. The data showed that 4 of these 490 E. coli strains (4/499, 0.8%) carried bla_SHV genes that included EC D2485 (bla_SHV-5), EC D2487 (bla_SHV-5), EC D2684 (bla_SHV-11) and EC D2616 (bla_SHV-195, a novel bla_SHV). Analysis of bla_SHV open-reading frame showed that bla_SHV-5 had a high hydrolysis activity to the broad-spectrum penicillin (ampicillin or piperacillin), ceftazidime, ceftriaxone, cefotaxime and aztreonam. bla_SHV-195 and bla_SHV-11 had similar resistant characteristics with high hydrolysis activities to ampicillin and piperacillin, but low activities to cephalosporins. Moreover, the two bla_SHV-5 genes were located on a transferable plasmid (23kb), whereas the other two bla_SHV variants (bla_SHV-11 and bla_SHV-195) seemed to be located in the chromosomal material. Both EC D2485 and EC D2487 clones isolated in 2010 had the same DNA finger printing profile and they might be the siblings of clonal dissemination. The data from the current study suggest that the novel bla_SHV and clonal dissemination may be developed, although bla_SHV genes were infrequently identified in this hospital population. The results of the work demonstrate the necessity for molecular surveillance in tracking bla_SHV-producing strains in large teaching hospital settings and emphasize the need for epidemiological monitoring.

Clinical and Molecular Epidemiology of Extended-Spectrum Beta-Lactamase-Producing Klebsiella spp.: A Systematic Review and Meta-Analyses

Healthcare-related infections caused by extended-spectrum beta-lactamase (ESBL)-producing Klebsiella spp. are of major concern. To control transmission, deep understanding of the transmission mechanisms is needed. This systematic review aimed to identify risk factors and sources, clonal relatedness using molecular techniques, and the most effective control strategies for ESBL-producing Klebsiella spp. A systematic search of PubMed, Embase, and Outbreak Database was performed. We identified 2771 articles from November 25th, 1960 until April 7th, 2014 of which 148 were included in the systematic review and 23 in a random-effects meta-analysis study. The random-effects meta-analyses showed that underlying disease or condition (odds ratio [OR] = 6.25; 95% confidence interval [CI] = 2.85 to 13.66) generated the highest pooled estimate. ESBL-producing Klebsiella spp. were spread through person-to-person contact and via sources in the environment; we identified both monoclonal and polyclonal presence. Multi-faceted interventions are needed to prevent transmission of ESBL-producing Klebsiella spp.

Antibiotics and Antifungals in Neonatal Intensive Care Units: A Review

The incidence of infections is higher in the neonatal period than at any time of life. The basic treatment of infants with infection has not changed substantially over the last years. Antibiotics (with or without supportive care) are one of the most valuable resources in managing sick newborn babies. Early-onset (ascending or transplacental) or late-onset (hospital acquired) infections present different chronology, epidemiology, physiology and outcome. Some classes of antibiotics are frequently used in the neonatal period: penicillins, cephalosporins, aminoglycosides, glycopeptides, monobactams, carbapenems. Other classes of antibiotics (chloramphenicol, cotrimoxazole, macrolides, clindamycin, rifampicin and metronidazole) are rarely used. Due to emergence of resistant bacterial strains in Neonatal Intensive Care Units (NICU), other classes of antibiotics such as quinolones and linezolid will probably increase their therapeutic role in the future. Although new formulations have been developed for treatment of fungal infections in infants, amphotericin B remains first-line treatment for systemic Candida infection. Prophylactic antibiotic therapy is almost always undesirable. Challenges from pathogens and antibiotic resistance in the NICU may warrant modification of traditional antibiotic regimens. Knowledge of local flora and practical application of different antibiotic characteristics are key to an effective and safe utilization of antibiotics and antifungals in critical newborns admitted to the NICU, and especially in very low birth weight infants.

Molecular analysis of a prolonged spread of Klebsiella pneumoniae co-producing DHA-1 and SHV-12 β-lactamases

The study investigated molecular mechanisms for prolonged nosocomial spread of multidrug-resistant Klebsiella pneumoniae co-producing plasmid-mediated AmpC β-lactamase DHA-1 and extended-spectrum β-lactamase SHV-12. Forty-eight clinical isolates of K. pneumonia, resistant to the extended-spectrum cepha-losporins, were collected in a 750-bed university hospital over a year. The isolates were characterized for PCR-based β-lactamase genotypes, isoelectric focusing and pulsed-field gel electrophoresis (PFGE) profiles. Resistance transfer was performed by plasmid conjugation and confirmed by a duplex-PCR and Southern hybridization. On β-lactamase typing, the strains producing only the DHA-1 enzyme (n=17) or co-producing DHA-1 and SHV-12 enzymes (n=15) were predominant. Judging from a one year-distribution of PFGE profiles, the co-producer was spread primarily with single clonal expansion of the PFGE-type A with subtypes (n=14), whereas the strains producing only DHA-1 enzyme were spread simultaneously with the PFGE-type A (n=ll) and other PFGE types (n=6). Transconjugants of the co-producers were confirmed to harbor either both bla (DHA-1) and bla (SHV-12) or only the bla (DHA-1). In conclusion, this study indicated that the persistent nosocomial spread of multidrug-resistant K. pneumoniae strains was primarily associated with expansion of a clone harboring both the bla (DHA-1) and bla (SHV-12) or the bla (DHA-1) only, and to a lesser extent with the horizontal transfer of the resistant plasmids. Our observations have clinical implication for the control and prevention of nosocomial dissemination of multidrug-resistant K. pneumoniae strains.

Outbreak caused by a multi-resistant Klebsiella pneumoniae strain of new sequence type ST341 carrying new genetic environments of aac(6')-Ib-cr and qnrS1 genes in a neonatal intensive care unit in Spain

An outbreak due to a Klebsiella pneumoniae clone occurred in a neonatal intensive care unit of a Spanish Hospital in which three newborns were infected (all with gestational age ≤29 weeks; two of them died) and seven were colonized (gestational age >32 weeks; none died). One K. pneumoniae strain per patient was further characterized. The 10 strains showed an indistinguishable pulsed-field-gel-electrophoresis pattern, were typed in the phylogenetic group KpI and were ascribed into a new sequence type registered as ST341. All 10 strains presented the same multiple-antibiotic-resistant phenotype, showed extended-spectrum-beta-lactamase production, and harbored the bla(CTX-M-15), bla(SHV-11), bla(OXA-1,)aac(6')-Ib-cr, qnrS1, aac(3)-II, aph(3')-Ia and aadA5 resistance genes. No class 1 or class 2 integrons were detected. The bla(CTX-M-15) gene presented the following genetic environment: ISEcp1-bla(CTX-M-15)-orf477. These strains contained two copies of the aac(6')-Ib-cr gene included in the following new genetic environments: aac(3)-II-IS26-aac(6')-Ib-cr-bla(OXA-1) and aac(3)-II-IS26-ΔcatB3-bla(OXA-1)-aac(6')-Ib-cr (registered at GenBank with accession numbers GQ438247 and GQ438248, respectively). The genetic environment of the qnrS1 gene (IS26-ΔISEcl2-qnrS1) (GenBank accession number GQ438249) was also not described previously. The aac(6')-Ib-cr, qnrS1, bla(CTX-M-15), aac(3)-II, and bla(OXA-1) genes, located in a plasmid of 33.5 kb, could be transferred to Escherichia coli by transformation.

[CTX-M-15-producing Klebsiella pneumoniae: a change in the epidemiology of ESBL]

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.

Multidrug-resistant bacteria in hospitalized children: a 5-year multicenter study

OBJECTIVE

The objective of this study was to determine the incidence of multidrug-resistant bacteria in hospitalized children.

METHODS

This multicenter study was conducted in 5 hospitals in the Paris area from 1999 to 2003. We recorded all isolations of multidrug-resistant bacteria from clinical samples that were obtained from hospitalized children. Strains that were isolated during systematic screening for carriers were excluded.

RESULTS

The mean incidences were 0.9 per 1000 hospitalization-days for methicillin-resistant Staphylococcus aureus, 0.45 for extended-spectrum beta-lactamase-producing Klebsiella pneumoniae, 0.32 for extended-spectrum beta-lactamase-producing Enterobacteriaceae other than Klebsiella pneumoniae, 0.40 for Enterobacter species with derepressed cephalosporinase, and 0.01 for vancomycin-resistant Enterococcus. The incidences per 1000 hospitalization-days of methicillin-resistant Staphylococcus aureus, extended-spectrum beta-lactamase-producing Klebsiella pneumoniae, extended-spectrum beta-lactamase-producing Enterobacteriaceae other than Klebsiella pneumoniae, and Enterobacter species with derepressed cephalosporinase decreased significantly from 1999 to 2003, whereas the incidence of vancomycin-resistant Enterococcus remained very low. The proportion of resistant strains within the species did not vary significantly for methicillin-resistant Staphylococcus aureus (11% to 9.6%), extended-spectrum beta-lactamase-producing Enterobacteriaceae other than Klebsiella pneumoniae (1.1%), and vancomycin-resistant Enterococcus (0.03% to 0.023%). In contrast, the frequency of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae decreased from 31.6% to 7.4%, and that of Enterobacter species with derepressed cephalosporinase decreased from 38.8% to 18.5%.

CONCLUSIONS

We report significant decreases in the incidence of methicillin-resistant Staphylococcus aureus, extended-spectrum beta-lactamase-producing Klebsiella pneumoniae, extended-spectrum beta-lactamase-producing Enterobacteriaceae other than Klebsiella pneumoniae, and Enterobacter species with derepressed cephalosporinase in hospitalized children during a 5-year period.