Recurrent outbreaks of Serratia marcescens among neonates and infants at a pediatric department: an outbreak analysis.

PURPOSE: Serratia marcescens is a known cause of bloodstream infections (BSIs) and outbreaks in neonates receiving intensive care. Our aim was to analyze clinical and epidemiological characteristics of two outbreaks detected in our unit to prevent and control further epidemic infections. METHODS: Two episodes of BSI outbreaks in neonates have been investigated in a 20-month period at a pediatric department of a medical university in Hungary. We collected all S. marcescens strains that were isolated in the study period, and two strains that were isolated before the outbreaks. Strains were analyzed by pulsed-field gel electrophoresis (PFGE). Clinical data were collected for the BSIs during and between the outbreaks (n = 14). RESULTS: Out of the 28 S. marcescens isolates investigated by PFGE, 16 were blood isolates. All isolates represented four PFGE types. Pathogenic strains that caused epidemic BSIs were related to a single PFGE type (SM009). Strains with the same pulsotype could be detected before, between, and after the outbreak periods from surveillance cultures of neonates, and a water tap in the infant care unit despite intensive infection control measures. Case fatality rate of BSIs was 29%. Rate of complications in central nervous system was high: 3/14 neonates developed meningitis. CONCLUSIONS: Rapid spread and high mortality rate of S. marcescens infections necessitate a high suspicion when isolating this species in neonatal intensive care. Early identification of outbreaks is essential, that can be facilitated by determination of clonal relatedness using molecular methods, and with regular surveillance cultures of patients and environment.

Fitness cost associated with resistance to fluoroquinolones is diverse across clones of Klebsiella pneumoniae and may select for CTX-M-15 type extended-spectrum ß-lactamase.

Lowered fitness cost associated with resistance to fluoroquinolones was recently demonstrated to influence the clonal dynamics of methicillin-resistant Staphylococcus aureus (MRSA) in the health care setting. We investigated whether or not a similar mechanism impacts Klebsiella pneumoniae. The fitness of K. pneumoniae isolates from major international hospital clones (ST11, ST15, ST147) already showing high-level resistance to fluoroquinolones and of strains from three minor clones (ST25, ST274, ST1028) in which fluoroquinolone resistance was induced in vitro was tested in a propagation assay. Strains from major clones showed significantly less fitness cost than three of four fluoroquinolone-resistant derivatives of minor clone isolates. In addition, plasmids with CTX-M-15 type extended-spectrum ß-lactamase (ESBL) genes were all retained in both major and minor clone isolates, irrespective of the strains' level of fluoroquinolone resistance, while each plasmid harboring SHV-type ESBLs had been lost during the induction of resistance. Major clone K. pneumoniae strains harbored more amino acid substitutions in the quinolone resistance determining regions (QRDRs) of the gyrA and parC genes than minor clone isolates. The presence of an active efflux system could be demonstrated in all fluoroquinolone-resistant derivatives of originally SHV-producing minor clone isolates but not in any CTX-M-15-producing strain. Further investigations are needed to expand and confirm our findings on a larger sample. In addition, a long-term observation of our ciprofloxacin-resistant minor clone isolates is required in order to elucidate whether or not they are capable of restoring their fitness while concomitantly retaining high minimum inhibitory concentration (MIC) values.

Emergence of VIM-4 metallo-ß-lactamase-producing Klebsiella pneumoniae ST15 clone in the Clinical Centre University of Pécs, Hungary.

Since November 2009 carbapenemase-producing Klebsiella pneumoniae isolates have been detected in increasing numbers at the Clinical Centre University of Pécs. Molecular typing was performed for 102 clinical isolates originating from different time periods and various departments of the Clinical Centre. Pulsed-field gel electrophoresis revealed the predominance of a single clone (101/102), identified as sequence type ST15. PCR and sequencing showed the presence of blaCTX-M-15 and blaVIM-4 genes. The blaVIM-4 was located on a class 1 integron designated In238b. To our knowledge, this is the first description of a blaVIM-4 gene in the predominant CTX-M-15 extended spectrum ß-lactamase-producing Hungarian Epidemic Clone/ST15.

From farm to fork follow-up of thermotolerant campylobacters throughout the broiler production chain and in human cases in a Hungarian county during a ten-months period.

A study tracking thermotolerant campylobacters from the setting of the broilers throughout the whole rearing period, slaughter and sale of chicken products in five consecutive broiler rotations of the same henhouse as well as in two different other farms was conducted in a well-defined geographic area (Hajdú-Bihar county, Hungary) between March 2006 and Feb 2007. All notified cases of human campylobacteriosis in this area during the study period were also included. One hundred and one, 44, 23 and 282 Campylobacter jejuni and 13, 15, 20 and 60C. coli were isolated from broiler houses, slaughterhouses, retail shops and human samples, respectively. Sixty-two isolates collected from broilers or their environment selected from different flocks (57C. jejuni, 5C. coli), 92 isolates collected from abattoirs and retail shops (72C. jejuni, 20C. coli), as well as 85 randomly selected human isolates (74C. jejuni, 11C. coli) were subjected to PFGE analysis using restriction enzymes KpnI and SmaI. Sixty-six of the isolates produced unique Sma-Kpn profiles; the majority (46) of these were of human origin. The remaining isolates formed PFGE clusters of between 2-25 isolates with 14 (12C. jejuni and 2C. coli) main clusters comprised of five or more isolates with identical KpnI-SmaI patterns. Two genetic clones of C. jejuni (clone A, n=25; clone B, n=20) included 18% of isolates from different sources. Generally, isolates from one cluster were found in 1-3 different flocks, notably, clone B was present in three rotations including those from the two independent farms. Six of the seven investigated flocks had one or two characteristic prevalent clones. Transmission of clones between consecutive flocks was frequently seen. Spread of both C. jejuni and C. coli was traced multiple times along the food chain; eight C. jejuni, but no C. coli clones were detected both in broilers and humans. These data suggest that broilers were the major source for C. jejuni but not for C. coli in the studied area and period. For C. jejuni the carryover of strains between consecutive flocks may be a common event, but the strain is eventually replaced by another and consecutive carryover events seem to be infrequent. The majority of the human disease was due to nonepidemic strains; some clones were transmitted from more than one broiler flocks (including epidemiologically unrelated flocks) to humans multiple times.

Dissemination of ST274 Klebsiella pneumoniae epidemic clone in newborn and adult hospital settings harbouring SHV-2A or CTX-M-15 type extended spectrum ß-lactamases-producing known plasmids.

Molecular epidemiology and genetic features of an extended-spectrum ß-lactamase (ESBL) producing Klebsiella pneumoniae epidemic clone (KP-EC) with elevated ciprofloxacin MIC (minimum inhibitory concentration) values from multiple nosocomial outbreaks and sporadic cases between 2006 and 2008 in Hungary were investigated. As a result of continuous monitoring of ESBL-producing KP-ECs, 27 isolates collected from five healthcare facilities were selected for macrorestriction profile analysis by PFGE (pulsed field gel electrophoresis). Of these, 12 strains were isolated from adult inpatients, while 15 strains were from newborns. The MIC values for several antibiotics were determined by agar dilution technique. Molecular typing was further performed by PCR (polymerase chain reaction) and sequencing of several antibiotic resistance genes, plasmid profile analysis, transfer of resistance determinants and multilocus sequence typing (MLST). All isolates showed moderate resistance to ciprofloxacin (MICs ranged from 0.5 to 8 mg L(-1)). PFGE revealed the existence of only one genetic cluster defined as EC IV. PstI digestion of plasmid DNA revealed two highly diverse restriction patterns in "adult" and "newborn" isolates corresponding to plasmids from the Hungarian Epidemic Clone and plasmids isolated from a neonatal nosocomial outbreak in 1998, respectively. Sequence analysis of ß-lactamase genes from plasmids of 14 selected isolates detected bla SHV-2a in strains isolated exclusively from newborns and bla CTX-M-15 in strains isolated exclusively from adult inpatients. MLST established that strains of the PFGE cluster belonged to a novel sequence type ST274. ESBL-producing K. pneumoniae isolates belonging to the novel sequence type ST274 appeared in the newborn and adult hospital settings in Hungary and acquired SHV-2a or CTX-M-15 type enzymes, respectively. Thus, a new antimicrobial resistance strategy for successful conformation to distinct hospital settings was found.

Emergence of a colistin-resistant KPC-2-producing Klebsiella pneumoniae ST258 clone in Hungary.

Nine Klebsiella pneumoniae isolates showing non-susceptibility to carbapenems were collected from three centres in the north-eastern region of Hungary. The minimum inhibitory concentrations (MICs) of antibiotics were determined by Etest. The putative production of a carbapenemase was tested by the modified Hodge test. The presence of bla (KPC) genes was verified by polymerase chain reaction (PCR) and sequencing. Furthermore, molecular typing was performed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). All isolates showed extensively drug-resistant (XDR) phenotype, and of these, eight isolates were highly resistant to colistin. The isolates carried bla (KPC-2), bla (SHV-12), bla (TEM-1) and bla (SHV-11). PFGE analysis of the nine KPC-2-producing Hungarian ST258 K. pneumoniae isolates, two KPC-2-producing Norwegian ST258 isolates and 33 CTX-M-15-producing ST11 isolates revealed the existence of one genetic cluster at an 88% similarity level. The overall results of the PFGE clustering, MLST and the presence of SHV-11 in both ST11 and ST258 suggest that this is the first hyperepidemic clonal complex of multidrug-resistant K. pneumoniae, probably CC258/CC340, possibly undergoing worldwide spread.