An outbreak of extended spectrum beta-lactamase producing Klebsiella pneumoniae in a neonatal intensive care unit

Klebsiella pneumoniae has long been a prominent cause of nosocomial infections and outbreaks have been observed in the intensive care units and in high risk groups. We present here a brief report on an outbreak of Klebsiella pneumoniae which occurred in a neonatal intensive care unit in our teaching hospital. As neonates are at highest risk for acquisition of Klebsiella pneumoniae producing extended spectrum beta-lactamase, infection control policies and procedures should be strictly followed to prevent such outbreaks.     

Nosocomial outbreak caused by Salmonella enterica serotype Livingstone producing CTX-M-27 extended-spectrum beta-lactamase in a neonatal unit in Sousse, Tunisia

In this study, we report an outbreak of Salmonella enterica serotype Livingstone resistant to extended-spectrum cephalosporins that occurred in a neonatal ward of the maternity department of Farhat Hached Hospital, Sousse, Tunisia, in 2002. A total of 16 isolates were recovered from 16 babies hospitalized in the ward during the period 1 to 16 July. All these babies developed diarrhea, and three of them developed septicemia. All the isolates demonstrated resistance to ceftriaxone and ceftazidime due to the production of an extended-spectrum beta-lactamase (ESBL). The isolates were also resistant to aminoglycosides (kanamycin, tobramycin, netilmicin, gentamicin, and amikacin) and sulfamethoxazole-trimethoprim. DNA profiles were determined by pulsed-field gel electrophoresis using the XbaI and SpeI endonucleases and by ribotyping with PstI digestion. They yielded the same patterns, showing that the outbreak was caused by a single clone. The ESBL was identified as CTX-M-27 by sequencing of PCR products and by isoelectric focusing. The ESBL resistance was transferred by a 40-kb conjugative plasmid. The mobile insertion sequence ISEcp1 was found to be located upstream of bla(CTX-M-27) in the same position as that known for a bla(CTX-M-14) sequence. A new gene named dfrA21, encoding resistance to trimethoprim and carried by a 90-kb plasmid, was characterized. The dfrA21 gene was inserted as a single resistance cassette in a class I integron. The babies were treated with colistin, and all except two recovered. The outbreak came to an end when appropriate actions were taken: patient isolation, hand washing, and disinfection of the ward.     

Nosocomial outbreak due to extended-spectrum-beta-lactamase- producing Enterobacter cloacae in a cardiothoracic intensive care unit

Enterobacter cloacae has been associated with several outbreaks, usually involving strains that overproduce chromosomal beta-lactamase or, uncommonly, strains expressing extended-spectrum beta-lactamases (ESBL). Only sporadic cases of ESBL-producing E. cloacae have been identified in our hospital in recent years. We describe the epidemiology and clinical and microbiological characteristics of an outbreak caused by ESBL-producing E. cloacae in a cardiothoracic intensive care unit (CT-ICU). Prospective surveillance of patients with infection or colonization by ESBL-producing E. cloacae among patients admitted to the CT-ICU was performed during the outbreak. Production of ESBL was determined by decreased susceptibility to expanded-spectrum cephalosporins and a positive double-disk test result. Clone relatedness was determined by pulsed-field gel electrophoresis (PFGE). From July to September 2005, seven patients in the CT-ICU with ESBL-producing E. cloacae were identified (four males; median age, 73 years; range, 45 to 76 years); six patients had cardiac surgery. Four patients developed infections; three had primary bacteremia, one had ventilator-associated pneumonia, and one had tracheobronchitis. ESBL-producing E. cloacae showed resistance to quinolones and aminoglycosides. PFGE revealed two patterns. Five isolates belonged to clone A; two carried a single ESBL (pI 8.2 and a positive PCR result for the SHV type), and three carried two ESBLs (pIs 8.1 and 8.2 and positive PCR results for the SHV and CTX-M-9 types). Isolates belonging to clone B carried a single ESBL (pI 5.4 and a positive PCR result for the TEM type). Review of antibiotic consumption showed increased use of cefepime and quinolones during June and July 2005. The outbreak was stopped by the implementation of barrier measures and cephalosporin restriction. ESBL production could be increasingly common in nosocomial pathogens other than Escherichia coli or Klebsiella pneumoniae.     

Streptococcus faecium outbreak in a neonatal intensive care unit

An outbreak of bacteremia and meningitis in a neonatal intensive care unit is described. Seven cases occurred in premature infants with severe underlying diseases. An epidemiological investigation failed to document the reservoir of the epidemic strain but suggested that its transmission among the infants was via the hands of hospital personnel. All patients had nasogastric tubes and multiple intravascular devices, and the portal of entry may have been either the gastrointestinal tract or the sites of the intravascular devices. Conventional biotyping of isolates failed to differentiate between isolates from infected patients and isolates recovered from prevalence surveys and from the environment. However, rapid identification systems (API-20S [Analytab Products, Plainview, N.Y.] and the AutoMicrobic system [Vitek Systems, Inc., Hazelwood, Mo.]) were able to distinguish isolates recovered from infected patients and hands of hospital personnel from isolates recovered during prevalence and environmental surveys and 29 isolates from widespread geographical areas. This is the first known report of a nosocomial neonatal outbreak of bacteremia and meningitis due to Streptococcus faecium; it underscores the importance of identifying streptococci to species level.     

Nosocomial outbreak of neonatal gastroenteritis caused by a new serotype 4, subtype 4B human rotavirus

A nosocomial outbreak of rotavirus gastroenteritis involving 52 newborns occurred between June and September 1988 at the University Children's Hospital of Freiburg, Federal Republic of Germany. Stools from 27 representative patients were examined for rotavirus serotypes, using a monoclonal antibody-based enzyme-linked immunosorbent assay. The electropherotype was also examined by polyacrylamide gel electrophoresis of genomic RNA. As many as 18 patients were found to be infected by serotype 4, subtype 4B strain, and in all of them the same electropherotype was detected. Although rotavirus from the remaining nine patients could not be typed, the electropherotype in four was identical to that of the serotype 4, subtype 4B strain. Thus, most of the patients in the outbreak were infected by the same rotavirus strain. Retrospective epidemiological studies showed that the 4B strain began to circulate at the hospital in January 1988, whereas only rotavirus serotypes 1, 3, and 4A were detected in 1985-1987. The primary case of the outbreak was presumably a newborn with acute gastroenteritis, admitted to the hospital from a small maternity unit in the same urban area. During the outbreak, 12 of 44 healthy newborns in the nurseries of the Children's Hospital and other maternity hospitals were found to be asymptomatic rotavirus carriers, and in three of the newborns the same 4B strain was detected. This is the first reported outbreak caused by a serotype 4, subtype 4B strain.     

Successful management of an MRSA outbreak in a neonatal intensive care unit

We report an MRSA outbreak in our 25-bed tertiary neonatal intensive care unit (NICU), which was successfully contained. Methods include a retrospective review of patient files, microbiology records and meeting protocols. During the seven months of outbreak, 27 patients and seven health care workers (HCWs) had positive cultures for MRSA. The outbreak was caused by the epidemic Rhine-Hessen strain; cultured isolates were monoclonal. After a sharp increase of the number of new MRSA-cases the installation of an outbreak management team (OMT) and implementation of comprehensive measures (extensive screening and decolonization strategy including orally applied vancomycin, isolation wards, intensive disinfection regimen) successfully terminated the outbreak within one month. Ten (53%) of 19 patients with completed follow-up and all of the HCWs were decolonized successfully. Gastrointestinal colonization was present in 15 of 27 (56%) neonates, and was associated with poor decolonization success (30% vs. 78% in absence of gastrointestinal colonization). A comprehensive outbreak management can terminate an outbreak in a NICU setting within a short time. Thorough screening of nares, throat and especially stool is necessary for correct cohorting. Gastrointestinal decolonization in neonates seems difficult.     

Molecular epidemiology of a cluster of cases due to Klebsiella pneumoniae producing SHV-5 extended-spectrum beta-lactamase in the premature intensive care unit of a Hungarian hospital

Fifteen nosocomial cases of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae occurred among 132 neonates in a premature intensive care unit in Hungary in June through November 1998. Fourteen strains were indistinguishable by molecular biological typing and harbored the same single conjugative extended-spectrum beta-lactamase-encoding plasmid that was spontaneously found in a Serratia marcescens strain in the same patient.     

Cholestasis in a neonatal intensive care unit

A retrospective study of 17 babies admitted to the neonatal intensive care unit of the Royal Maternity Hospital, Belfast, was undertaken to determine the causes and prognosis of conjugated hyperbilirubinaemia (direct fraction greater than 20% of total) over a five year period. Mean gestational age was 29 weeks and mean birth weight was 1,240g with a 2:1 male preponderance. All babies had a complicated clinical course involving prolonged periods of parenteral nutrition and many episodes of sepsis. Liver damage was not found to be a contributory factor to death in any baby who died before the age of one year. Bilirubin levels in the survivors had returned to normal within one year. No permanent pathological cause of cholestasis, such as biliary atresia, was ascribable to any of the cases, indicating that extensive investigation to exclude anatomical causes in this population is unlikely to prove rewarding.     

Nosocomial spread of a Staphylococcus capitis strain with heteroresistance to vancomycin in a neonatal intensive care unit

A premature infant in a neonatal intensive care unit (NICU) developed a bloodstream infection caused by coagulase-negative staphylococci (CoNS) sensitive to vancomycin. The infection persisted for 3 weeks, despite therapy with vancomycin and replacement of all intravenous catheters. The neonate died due to necrotizing enterocolitis which developed during the ongoing sepsis. We screened this strain and 216 other strains of CoNS from cultures of blood obtained from neonates between 1997 and 2000 for heteroresistance to vancomycin. Forty-eight isolates, including the strain that caused ongoing sepsis, proved heteroresistant. All isolates were identified as Staphylococcus capitis and were identical, just as their resistant stable subcolonies were, when they were genetically fingerprinted by amplified-fragment length polymorphism analysis. The heteroresistant phenotype of this endemic strain was confirmed by population analysis. We conclude that heteroresistance to vancomycin occurs in S. capitis and might be the cause of therapeutic failures in NICUs. Moreover, heteroresistant strains can become endemic in such units.     

Case control study of extended-spectrum betalactamase producing Serratia marcescens outbreak in a paediatric intensive care unit

OBJECTIVES: To identify patient-related risk factors of infection and ways of transmission of extended-spectrum betalactamase (ESBL) producing Serratia marcescens in the paediatric intensive care unit (PICU) of Amiens university hospital (France) between June and July 2002. METHODS: Five cases (four pulmonary infected and one stool contaminated symptom-free neonates) and 35 controls, admitted in the PICU, are included. S. marcescens ESBL analysed are isolated from respiratory tract and faecal samples for cases and urine and pus samples from two non-paediatric other patients. Univariate and multivariate analysis are performed on EPI INFO 6.04 dFr and SPSS 11.0.1. RESULTS: S. marcescens ESBL infections or colonisations rate is 12.5% [4.7-27.6]. The incidence is 8.8 [6.7-11.6] per 1000 hospital-stay days. By univariate analysis, cases and controls don't differ with respect of age, sex, and weight at admission or preterm delivery. Cases don't have more often invasive nursing care than controls. But, they were intubated (P <0.03) and hospitalised (P <0.03) for a longer time than controls. Linear regression analysis showed that duration of intubation was independent predictor of acquisition of S. marcescens ESBL (P <0.008). S. marcescens ESBL strains implicated in pulmonary infections, showed the same pattern of multidrug resistant and ERIC-PCR profile. This clone differs from others isolated from stool or other samples from other hospital wards. CONCLUSION: As S. marcescens cross-colonization appears to be due to lake of hand hygiene and asepsis during invasive nursing care, reinforcing hygiene measures permit to contain the outbreak.     

Outbreak of septicaemic cases caused by Acinetobacter ursingii in a neonatal intensive care unit

Neonatal infections may be caused by various microorganisms, but as far as we are aware, Acinetobacter ursingii has not yet been reported in connection with nosocomial infections of premature infants. During 2 months, 3 premature babies were treated with nosocomial infection caused by A. ursingii at the same ward, and on the basis of molecular typing results the same strain was responsible for all of these cases. Traditional biochemical methods and automatic identification systems failed to identify this bacterium on the species level, and only 16S rDNA sequencing gave acceptable species identifications. The isolated strains proved to be susceptible to all of the tested antimicrobials, including ampicillin/sulbactam, doxycyclin, netilmicin, ciprofloxacin, piperacillin/tazobactam, ceftazidime, imipenem, meropenem, trimethoprim/sulfametoxazole, gentamicin, tobramycin, amikacin, and levofloxacin according to the CLSI standard. In spite of the environmental screening, the source of the infection could not be clarified. One of 3 neonates died, the others recovered and were discharged home after several months of hospitalization.     

一起由札如病毒引起的急性胃肠炎暴发疫情的分子流行病学研究

目的 调查深圳市某幼儿园发生的一起急性胃肠炎暴发疫情的病原体,并分析病原体的分子流行病学特征.方法 收集患病幼儿及相关人员的粪便标本16份,剩余食物6份,采用国家卫生行业标准规定方法检测肠道致病菌、实时荧光RT-PCR法检测诺如病毒、札如病毒、轮状病毒核酸,逆转录RT-PCR法对病毒衣壳区和聚合酶区序列进行扩增,对PCR产物进行序列测定.序列用Clustalx软件进行多重比对、Mega 5.0软件绘制系统进化树.结果 16份样本中检出11例札如病毒核酸阳性,对其中3例阳性标本进行札如病毒衣壳区和聚合酶区序列测定,3株札如病毒与GII.3型参考株AY603425衣壳区核苷酸同源性为86.3％,聚合酶区核苷酸同源性为90.2％,3株札如病毒与GII.3型参考株AY603425、AB455793同属于GII.3型遗传分支.结论 此起急性胃肠炎爆发是由GII.3型札如病毒导致,GII.3型引起的急性胃肠炎暴发属广东省首次报道.     

Healthcare-associated infections in a neonatal intensive care unit

Introduction

Healthcare-associated infection is a common problem in patients from neonatal intensive care units and it is one of the leading causes of death in this group of patients. Healthcare-associated infections are associated with increases in mortality, morbidity, and prolonged length of hospital stay. The aim of the study was to assess the incidence, clinical presentation, mortality and aetiology of healthcare-associated infections in newborns in a neonatal intensive care unit between 2005 and 2010.

Material and methods

The research involved documentation of 2610 neonates hospitalized in this period in the Neonatal Intensive Care Unit, Dr Jan Biziel University Hospital No. 2 in Bydgoszcz. The incidence, clinical presentation, mortality and causative factors of healthcare-associated infections were assessed.

Results

The prevalence of healthcare-associated infections was 7.32%. The most frequent healthcare-associated infections were bloodstream infection (65.4%) and urinary tract infection (22.5%). The mortality rate was 2.1%. The most frequent pathogens were coagulase-negative staphylococci (36.1%) and Klebsiella pneumoniae (29.3%).

Conclusions

The rate of healthcare-associated bloodstream infections in the analysed department is low, taking into consideration the specificity of the department. There is a necessity to establish convenient definitions of various kinds of healthcare-associated infecions in neonates, especially those born preterm.     

Emergence of VIM-4- and SHV-12-producing Enterobacter cloacae in a neonatal intensive care unit

In order to reveal colonization with multidrug-resistant bacteria early, routine screening is done on samples of all patients of the neonatal intensive care units at Semmelweis University, Hungary. Due to the extended-spectrum β-lactamase (ESBL) screening examinations, emergence of multidrug-resistant Enterobacter cloacae isolates was found with suspicion of clonal transmission, therefore active microbiological surveillance was initiated. The aim of our study was to characterize 60 E. cloacae isolates recovered in a 7-month period in 2010. MIC values of antibiotics were determined and ESBL and carbapenemase production was tested. Metallo-β-lactamase (MBL) genes, ESBL genes, and class-1 integrons were characterized, and the possible clonal relationship between isolates was investigated. The isolates showed increased MIC values for carbapenems and cephalosporins. All 60 E. cloacae strains recovered from 16 neonates proved to be VIM-4 MBL producers. Fifty-three strains were SHV-12 ESBL producers also. In all cases, the bla_VIM-4 gene was a part of class-1 integron, In238a. XbaI-macrorestriction analysis by pulsed-field gel electrophoresis (PFGE) revealed identical patterns for the isolates. Our study supports the importance of active microbiological surveillance as well as molecular epidemiology at the NICUs as a part of infection control.     

Nosocomial spread of a Staphylococcus hominis subsp. novobiosepticus strain causing sepsis in a neonatal intensive care unit

From 2002 to 2003, 32 isolates of Staphylococcus hominis subsp. novobiosepticus (SHN) were recovered from 21 patients, 18 of whom were neonates, with 13 considered to have late-onset SHN sepsis. All isolates from neonates had an indistinguishable pulsed-field gel electrophoresis pattern. Our data support SHN as an important nosocomial pathogen in neonates.     

First outbreak of multidrug-resistant Klebsiella pneumoniae producing both SHV-12-type extended-spectrum beta-lactamase and DHA-1-type AmpC beta-lactamase at a Korean hospital

PURPOSE: Coexistence of different classes of beta-lactamases in a single bacterial isolate may pose diagnostic and therapeutic challenges. We investigated a spread of Klebsiella pneumoniae isolates co-producing an AmpC beta-lactamase and an extended-spectrum beta-lactamase (ESBL) in a university hospital. MATERIALS AND METHODS: Over a three-month period, a total of 11 K. pneumoniae isolates, which exhibited resistance to cefotaxime, aztreonam, and cefoxitin, were isolated. These isolates showed positive to ESBLs by double disk tests. Minimal inhibitory concentrations (MICs) were determined by broth microdilution testing. All isolates were examined by isoelectric focusing, PCR and sequence analysis to identify bla(SHV) and bla(DHA), and molecular typing by pulsed-field gel electrophoresis (PFGE). RESULTS: All 11 isolates were highly resistant (MIC, > or = 128microg/ml) to ceftazidime, aztreonam, and cefoxitin, while they were susceptible (MIC, < or = 2microg/ml) to imipenem. The bla(SHV-12) and bla(DHA-1) genes were detected by PCR and sequence analysis. PFGE revealed a similar pattern in 10 of the 11 strains tested. CONCLUSION: This is the first outbreak report of K. pneumoniae in Korea which co-produced SHV-12 and DHA-1 beta-lactamase, and we suggest a clonal spread of multidrug-resistant K. pneumoniae at a hospital.     

Methicillin-resistant Staphylococcus caprae in a neonatal intensive care unit

Staphylococcus caprae, a hemolytic coagulase-negative staphylococcus that is infrequently associated with humans, was initially detected in specimens from six infants in our neonatal intensive care unit due to phenotypic characteristics common to methicillin-resistant Staphylococcus aureus. These isolates were subsequently identified as S. caprae by the Automated RiboPrinter microbial characterization system. This prompted an 8-month retrospective investigation in our neonatal intensive care unit. S. caprae was the cause of 6 of 18 episodes of coagulase-negative staphylococcal bacteremia, was the most common coagulase-negative staphylococcus recovered from the nares of 6 of 32 infants surveyed in a methicillin-resistant S. aureus surveillance program, and was isolated from 1 of 37 health care providers' hands. Of 13 neonatal intensive care unit isolates tested, all were methicillin resistant and positive for the mecA gene. All 21 isolates were found to be a single strain by Automated RiboPrinter and pulsed-field gel electrophoresis with ApaI or SmaI digestion; ApaI was more discriminating in analyzing epidemiologically unrelated strains than Automated RiboPrinter or electrophoresis with SmaI. These findings extend the importance of S. caprae, emphasize its similarities to methicillin-resistant S. aureus, and demonstrate its ability to persist in an intensive care unit setting.     

Nosocomial infection in newborns by Pichia anomala in a Brazilian intensive care unit.

Disseminated candidiasis is the most common nosocomial fungal infection, and Candida albicans has been reported to account for 50% to more than 70% of cases of invasive candidiasis. However, recent reports have also suggested the emergence of infections caused by non-albicans species. In addition, less-common pathogenic yeasts (Malassezia, Trichosporon, Rhodotorula, Debaryomyces and Pichia) have recently been reported, with increased frequency, as causes of nosocomial infections with high mortality. This article describes two cases of fungemia caused by Pichia anomala in newborns that occurred in an intensive care unit (ICU), in November 2004 at the Instituto da Crian?a (Pediatric Institute) of the Hospital das Clínicas of the School of Medicine, S?o Paulo University, Brazil. The principal factors related to virulence (proteinase and phospholipase) and the susceptibility of the isolated strains to antifungal agents were also evaluated, and the biotype of each strain was determined through the use of an epidemiological marker (killer biotype).