Environmental survival of vancomycin-sensitive ampicillin-resistant Enterococcus faecium (AREfm).

Ampicillin-resistant Enterococcus faecium (AREfm) has gained increased footholds in many hospital intensive care units (ICUs) and belongs to specific hospital-adapted E. faecium sub-populations. Three AREfm strains survived in an in vitro survival setting for approximately 5.5 years. These findings have important consequences for the epidemiology of AREfm in hospital settings and stress the importance of maintaining a good level of hospital hygiene.

Ciprofloxacin-induced hemorrhagic vasculitis.

Ciprofloxacin-induced hemorrhagic vasculitis is a rare side effect. It has only been described in 10 case reports since 1989. However, recently we were confronted with two cases within 1 month. In one patient the vasculitis resolved after termination of the ciprofloxacin therapy; in the other patient the ciprofloxacin-induced hemorrhagic vasculitis was superimposed on a severe forefoot infection, leading to progressive gangrene and a below-knee amputation. Ciprofloxacin is among the standard treatments for infected ischemic ulcers; in the rare case of ciprofloxacin-induced hemorrhagic vasculitis, it might be interpreted as progression of infection, instead of a complication of the treatment, thus leading to faulty diagnosis and treatment. The intention of this case report is to raise awareness for anyone prescribing ciprofloxacin as treatment for infected diabetic and ischemic ulcers.

Amoxicillin/clavulanate (Augmentin) resistant Escherichia coli in bacterial peritonitis after abdominal surgery--clinical outcome in ICU patients.

Bacterial resistance to antimicrobial agents is of great concern to clinicians. Patient outcome after infection is mainly dependent on the sensitivity of the bacterium to the agent used. We retrospectively studied 89 postoperative intensive care unit (ICU) patients with proven Escherichia coli peritonitis and investigated the clinical consequences of the E. coli resistance to amoxicillin/clavulanate. Significantly increased mortality, days of ventilation and ICU stay were noted in the co-amoxicillin/clavulanate resistant group. Furthermore, our results demonstrate that the sensitivity of E. coli to amoxicillin/clavulanate in the postoperative ICU setting has decreased in recent years. We can conclude that the current antibiotic regimen for the empirical treatment of ICU patients with peritonitis, as used in our hospital, needs to be changed. A switch, for instance, to ceftriaxone (Rocephin) in combination with metronidazole and gentamicin, instead of the present regimen of amoxicillin/clavulanate in combination with gentamicin, seems preferable.

Concentration-dependency of beta-lactam-induced filament formation in Gram-negative bacteria.

Ceftazidime and cefotaxime are beta-lactam antibiotics with dose-related affinities for penicillin-binding protein (PBP)-3 and PBP-1. At low concentrations, these antibiotics inhibit PBP-3, leading to filament formation. Filaments are long strands of non-dividing bacteria that contain enhanced quantities of endotoxin molecules. Higher concentrations of ceftazidime or cefotaxime cause inhibition of PBP-1, resulting in rapid bacterial lysis, which is associated with low endotoxin release. In the present study, 37 isolates of Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa and Acinetobacter spp. were studied over a 4-h incubation period in the presence of eight concentrations of ceftazidime or cefotaxime. As resistance of Gram-negative bacteria is an emerging problem in clinical practice, 14 isolates of E. coli and Klebsiella pneumoniae that produced extended-spectrum beta-lactamases (ESBLs) were also investigated. Morphological changes after exposure to the beta-lactam antibiotics revealed recognisable patterns in various bacterial families, genera and isolates. In general, all isolates of Enterobacteriaceae produced filaments within a relatively small concentration range, with similar patterns for E. coli and K. pneumoniae. Pseudomonas and Acinetobacter spp. produced filaments in the presence of clinically-relevant concentrations of both antibiotics as high as 50 mg/L. In all genera, filament-producing capacity was clearly related to the MIC. Ceftazidime induced filament production in more isolates and over wider concentration ranges than did cefotaxime. Interestingly, ESBL-producing isolates were not protected against filament induction. The induction of filament production may lead to additional risks during empirical treatment of severe infections.

Comparison of an enrichment broth-enhanced commercial PCR procedure versus bacteriological culture for separating non-colonized from suspected or colonized MRSA individuals.

The aim of the study presented here was to evaluate an enrichment broth-enhanced commercial PCR procedure for excluding the presence of meticillin-resistant Staphylococcus aureus (MRSA) in patient samples in less than 36 h. In The Netherlands to date, all MRSA epidemics have been successfully controlled with the Dutch search-and-destroy policy. However, PCR facilitates more rapid screening for MRSA than traditional culture. One commercial PCR option is the hyplex StaphyloResist(R) PCR assay (Biologische Analysensystem GmbH, Lich, Germany), which detects Staphylococcus aureus and the mecA gene in MRSA as well as in coagulase-negative staphylococci (CoNS). This assay was used to test a total of 939 specimens obtained from 346 individuals. Following resolution of all discrepancies, the prevalence, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for all separate specimens were 9.0, 97.6, 83.7, 37.4 and 99.7%, respectively, and for specimens grouped according to daily episode submitted per individual, they were 7.5, 97.4, 77.2, 26.2 and 99.7%, respectively. These results led to the introduction of this PCR into the hospital laboratory's routine for the purpose outlined above.

[An outbreak of scarlet fever, impetigo and pharyngitis caused by the same Streptococcus pyogenes type T4M4 in a primary school]. / Een epidemie van roodvonk, impetigo en faryngitis veroorzaakt door dezelfde Streptococcus pyogenes type T4M4 op een basisschool.

UNLABELLED: EPIDEMIC: Following the notification of an unusual number of scarlet fever cases within the same primary school, the epidemiological and clinical features of the outbreak were investigated. Questionnaire information about the cases was collected from parents and general practitioners per telephone. Throat specimens were taken, before and after treatment, for culturing and specific typing of streptococci was performed to determine transmission. Within a period of one month, 21 schoolchildren in a class of 29 pupils, with a mean age of 5 years, presented with symptoms caused by streptococcal infection (attack rate: 72%). Eight had scarlet fever, 5 suffered from impetigo and 8 had pharyngitis. A further 6 children, outside of this class, had complaints of scarlet fever, impetigo or pharyngitis. For 90% (26/29) of the schoolchildren a throat culture was established. Twelve positive cultures of the same strain of beta-haemolytic group A streptococcus, T4M4 exotoxin C gene positive, were found. The advice given was to treat all positive children for 3 days with azithromycin to prevent complications and further spreading of the disease. After two weeks only one child, that had not taken the antibiotics, still had a positive throat culture. No further cases or complications were reported. DISCUSSION: The pattern of the outbreak was typical of a person-to-person transmission. This was confirmed by typing of the isolates. The results of this study demonstrate the importance of mandatory notification of infectious clusters by institutions, such as schools, as introduced in the new Dutch Infectious Disease Act. On the one hand, the notification gives the municipal health authority the opportunity to analyse source and transmission dynamics and on the other to prevent disease and complications.

Better environmental survival of outbreak vs. sporadic MRSA isolates.

Environmental sources have been associated with prolonged epidemics of methicillin-resistant Staphylococcus aureus (MRSA). Our objective was to evaluate whether outbreak MRSA strains differ in their environmental survival from sporadic MRSA strains. The strains were detected in five adult patients unknowingly colonized by MRSA. The MRSA strains from patients No. 1 (phage pattern; III-29) and No. 2 (III-215) caused extensive outbreaks in our hospital. Contact tracing after detection of the different MRSA strains in the three other patients did not reveal further spread. Suspensions of MRSA with and without added hospital dust were made in sterile PBS. Surviving counts of MRSA were made by culture at two-weekly or longer intervals up to approximately one year. For each MRSA strain the ultimate day of viability was ascertained. The environmental survival patterns of the five MRSA strains showed qualitative and quantitative differences between the two outbreak and three sporadic strains. A gradual decline was noted for all strains. All survived longer than 6 months, but the two outbreak strains survived significantly better (P<0.01), i.e. in higher quantities (circa 1000-fold) and for a 1-3 months longer period. The survival patterns of the MRSA strains with and without added dust were similar.