Risk assessment of the mechanical spread of bacterial pathogens due to Lasius neglectus ants infesting a tertiary hospital.

INTRODUCTION: Mechanical spread of microbial pathogens has been investigated in cockroaches, but less well in ants. Considerably less information is available for ants. An investigation into ant-borne mechanical pathogen transmission was triggered by an infestation of a tertiary care hospital with Lasius neglectus ants. METHODS: The L. neglectus infestation of the orthopaedic surgery department, the ear-nose-throat clinic and the eye clinic as well as of outdoor areas was monitored and correlated with seasonal and weather influences. Microbial colonization on the ants' exoskeleton as well as in homogenates of complete insects and decolonization dynamics of artificial Staphylococcus aureus colonization on the exoskeleton was assessed. RESULTS: In a low-level infestation setting, L. neglectus activity showed seasonal variations and was positively correlated with temperature (r = 0.7515; P=0.0368) but not with precipitation (r = 0.4699, P=0.2431). Colonization with environmental commensals dominated, while exoskeleton colonization with bacteria with potential aetiological relevance for nosocomial infections was higher for ants from the inpatient setting (6%) than from outdoor areas (0%). Artificial colonization of the exoskeleton with S. aureus vanished to values statistically indistinguishable from baseline within 72 h. CONCLUSIONS: Low colonization rates with aetiologically relevant bacteria and rapid spontaneous decolonization in the case of contamination make ant-borne transmissions to patients unlikely.

Introducing "Rapid phage susceptibility testing" (RPST): an accelerated lytic phage activity test for routine diagnostic laboratories within eight hours.

Phage therapy, particularly for infections due to multi-drug-resistant bacteria, is increasingly gaining in importance. Consecutively, there is a rising need for phage testing in routine diagnostic laboratories. The incubation time of phage susceptibility testing for detecting lytic phage activity on phage/host strain combinations was evaluated. A standardized approach for routine diagnostic laboratories provided reliably detectable lysis zones within 8 hours.

Influence of bed making on loads of airborne and surface-associated drug-resistant bacteria in patient rooms.

INTRODUCTION: Limited information is available on the kinetics of airborne multi-drug-resistant bacteria after making patients' beds. Previous experience of bed making on loads of meticillin-resistant Staphylococcus aureus (MRSA) was re-evaluated with a substantial sample size and, for the first time, simultaneous examination of the environmental load of multi-drug-resistant Gram-negative bacteria (MDRGN) was undertaken. METHODS: Airborne pathogen measurement was carried out in 26 rooms with patients with MRSA and 25 rooms with patients with MDRGN before (-1 min) and after (1 min, 15 min, 60 min) bed making at distances of 0 m and 3 m from the bed. Surface sampling was performed in the patients' surroundings. Factors of potential influence were recorded. RESULTS: Gram-positive non-pathogenic species dominated the air samples, while Gram-negative organisms constituted only 1.4%. Bed making shifted the proportions towards coagulase-negative staphylococci and S. aureus. A transient increase in MRSA in room air was detected in most samples 1 min and 15 min after bed making. MDRGN were detected in the air of two patient rooms. Surface samples showed that MRSA, but not MDRGN, was isolated regularly in the patient environment. Correlation between airborne and surface pathogen loads after bed making was demonstrated. CONCLUSIONS: The study results indicate the importance of wearing a face mask in combination with cautious handling techniques when making the beds of patients carrying multi-drug-resistant bacteria. If the carrier status of a patient is unknown, consideration should be given to protective measures for staff and other patients present during and shortly after bed making. Surface disinfection should not be started until at least 30 min after bed making.

Molecular epidemiology study of a nosocomial Moraxella catarrhalis outbreak in a neurological rehabilitation unit.

BACKGROUND: Moraxella catarrhalis is a common agent causing upper and lower respiratory tract infections, particularly of ventilated patients. The bacteria are transmitted between humans by direct and indirect contacts. However, reports of nosocomial outbreaks by this pathogen are scarce. AIM: To analyse M. catarrhalis strains isolated during an outbreak in a medical rehabilitation centre to reveal their clonal relationship and to elucidate potential transmission routes. METHODS: Extensive environmental and medical staff sampling was performed. Phenotypic and genotypic analyses of 15 isolates were executed, including repetitive element palindromic polymerase chain reaction (repPCR) and whole-genome sequencing. Furthermore, an intensified hygiene regimen was installed. FINDINGS: The clonal nature of nine patient isolates and a simultaneous presence of separate entities including a strain isolated from a physician during staff screening was confirmed. Although neither asymptomatic carriers among the staff persons nor outbreak strain-contaminated fomites were identified for a specific intervention, the outbreak ceased due to maximum general and specific hygiene precautions. Retrospective analysis showed the increasing prevalence of M. catarrhalis strains over a period of two years before the incidence. Since then and after returning to the regular hygiene regimen, only one patient with a phenotypically diverse M. catarrhalis isolate has been documented. CONCLUSION: The first M. catarrhalis outbreak involving nine patients of a neurological and trauma rehabilitation centre was reported. Potential transmission pathways were discussed. Comprehensive outbreak analyses insinuated the extension of routine laboratory storage time for defined species.

Comparing a single-day swabbing regimen with an established 3-day protocol for MRSA decolonization control.

OBJECTIVES: Success of methicillin-resistant Staphylococcus aureus (MRSA) decolonization procedures is usually verified by control swabs of the colonized body region. This prospective controlled study compared a single-day regimen with a well-established 3-day scheme for noninferiority and adherence to the testing scheme. METHODS: Two sampling schemes for screening MRSA patients of a single study cohort at a German tertiary-care hospital 2 days after decolonization were compared regarding their ability to identify MRSA colonization in throat or nose. In each patient, three nose and three throat swabs were taken at 3- to 4-hour intervals during screening day 1, and in the same patients once daily on days 1, 2 and 3. Swabs were analysed using chromogenic agar and broth enrichment. The study aimed to investigate whether the single-day swabbing scheme is not inferior to the 3-day scheme with a 15% noninferiority margin. RESULTS: One hundred sixty patients were included, comprising 105 and 101 patients with results on all three swabs for decolonization screening of the nose and throat, respectively. Noninferiority of the single-day swabbing scheme was confirmed for both pharyngeal and nasal swabs, with 91.8% and 89% agreement, respectively. The absolute difference of positivity rates between the swabbing regimens was 0.025 (-0.082, 0.131) for the nose and 0.006 (-0.102, 0.114) (95% confidence interval) for the pharynx as calculated with McNemar's test for matched or paired data. Compliance with the single-day scheme was better, with 12% lacking second-day swabs and 27% lacking third-day swabs from the nostrils. CONCLUSIONS: The better adherence to the single-day screening scheme with noninferiority suggests its implementation as the new gold standard.

Validated measurements of microbial loads on environmental surfaces in intensive care units before and after disinfecting cleaning.

AIMS: Preanalytic aspects can make results of hygiene studies difficult to compare. Efficacy of surface disinfection was assessed with an evaluated swabbing procedure. METHODS AND RESULTS: A validated microbial screening of surfaces was performed in the patients' environment and from hands of healthcare workers on two intensive care units (ICUs) prior to and after a standardized disinfection procedure. From a pure culture, the recovery rate of the swabs for Staphylococcus aureus was 35%-64% and dropped to 0%-22% from a mixed culture with 10-times more Staphylococcus epidermidis than S. aureus. Microbial surface loads 30 min before and after the cleaning procedures were indistinguishable. CONCLUSIONS: The quality-ensured screening procedure proved that adequate hygiene procedures are associated with a low overall colonization of surfaces and skin of healthcare workers. Unchanged microbial loads before and after surface disinfection demonstrated the low additional impact of this procedure in the endemic situation when the pathogen load prior to surface disinfection is already low. SIGNIFICANCE AND IMPACT OF THE STUDY: Based on a validated screening system ensuring the interpretability and reliability of the results, the study confirms the efficiency of combined hand and surface hygiene procedures to guarantee low rates of bacterial colonization.

Predictors of colonization with Staphylococcus species among patients scheduled for cardiac and orthopedic interventions at tertiary care hospitals in north-eastern Germany-a prevalence screening study.

As methicillin-resistant Staphylococcus aureus (MRSA) colonization and infection in humans are a global challenge. In Mecklenburg and Western Pomerania (Germany) 1,517 patients who underwent surgical interventions were systematically screened for MRSA and MSSA colonization on the day of hospital admission and discharge. Demographic data, risk factors and colonization status of the (i) nose, (ii) throat, (iii) groin, and (iv) thorax or site of surgical intervention were determined. Of the 1,433 patients who were included for further evaluation, 331 (23.1%) were colonized with MSSA, while only 17 (1.2%) were MRSA carriers on the day of hospital admission. A combination of nose, throat and groin swabs returned a detection rate of 98.3% for MSSA/MRSA. Trauma patients had lower prevalence of MRSA/MSSA (OR 0.524, 95% CI: 0.37-0.75; p < 0.001) than patients with intended orthopedic interventions. Males showed significantly higher nasal S. aureus carrier rates than females (odds ratio (OR) = 1.478; 95% CI: 1.14-1.92; p = 0.003). Nasal S. aureus colonization was less frequent among male smokers as compared to non-smokers (chi2 = 16.801; phi = 0.154; p < 0.001). Age, gender and smoking had a significant influence on S. aureus colonization. Combining at least three different swabbing sites should be considered for standard screening procedure to determine S. aureus colonization at patients scheduled for cardiac or orthopedic interventions at tertiary care hospitals.

Difficulties in species identification within the genus Haemophilus - A pilot study addressing a significant problem for routine diagnostics.

Diagnostic misidentifications of commensalic Haemophilus haemolyticus as pathogenic Haemophilus influenzae are frequent. This pilot study evaluates whether isolations of H. haemolyticus are frequent enough in Germany to cause a relevant diagnostic problem, considering the fact that even H. influenzae is a mere colonizer in about 30% of isolations. In microbiological laboratories of two hospitals located in Northern and Southern Germany, the distribution of Haemophilus spp. was analyzed during a six-month-period. Site of infection, sex, and age of the patients was taken into consideration. A total of 77 Haemophilus spp. isolates was acquired and discriminated on species level, comprising: 48 H. influenzae, 25 Haemophilus parainfluenzae, 3 H. haemolyticus, and 1 Haemophilus parahaemolyticus. The proportion of H. haemolyticus was calculated to range between 1.2% and 16.2 % within the 95% confidence limits. Commensalic Haemophilus spp. were isolated from oropharynx-associated sites only. H. influenzae, in contrast, was detected in clinically relevant materials like lower respiratory materials and conjunctiva swabs. Altogether, there was a low proportion of clinical H. haemolyticus isolates. Accordingly, the problem of unnecessary antibiotic therapies due to misidentifications of H. haemolyticus as H. influenzae is quantitatively negligible compared with the risk of confusing H. influenzae colonizations with infections.

[Surveillance reports on pathogens and their antibiotic resistance patterns - a recommendation for standardization]. / Surveillanceberichte zu Erregern und Antibiotikaresistenzen - eine Empfehlung zur Standardisierung.

Surveillance reports on infectious agents and their antibiotic resistance patterns as well as on the usage of antibiotics are now enforced by law for many medical institutions in Germany. However, specific practice-oriented recommendations concerning the appropriate extent and informative mode of presentation are lacking. This consensus statement resulted from the experience from five German university hospitals in handling data from infection epidemiology and in the various possibilities for the presentation of surveillance reports. The consensus statement provides recommendations for the preparation of the legally demanded surveillance reports, extending the existing regulations. The relevance of statements on frequency and quality of microbiological tests is included. Furthermore, modes for the standardization of the data analysis are suggested in order to achieve a regional and national comparability of the results on a high quality level, similarly to the established standardized surveillance of nosocomial infections. This consensus statement describes the form in which the legally enforced reports can be presented in an informative and standardized way in order to facilitate the deduction and realization of preventive measurements.

Ciprofloxacin reduces the risk of hemolytic uremic syndrome in patients with Escherichia coli O104:H4-associated diarrhea.

BACKGROUND: Whether antibiotic treatment in patients with enterohemorrhagic Escherichia coli (EHEC)-associated diarrhea influences the risk of hemolytic uremic syndrome (HUS) has still to be elucidated. PATIENTS AND METHODS: During the EHEC epidemic which occurred in northern Germany in spring 2011, 24 patients with E. coli O104:H4 infection were treated at our hospitals, 19 of whom developed HUS. The use of antibiotics before and after the onset of HUS was documented, and the outcome in patients with and without antibiotic treatment was evaluated. RESULTS: Of the 24 patients with EHEC-associated diarrhea, seven received antibiotics before any signs of HUS were present (ciprofloxacin, cefotaxime, amoxicillin and/or metronidazole). Four of these seven patients (57 %) and 15 of the 17 patients (88 %) who were treated without antibiotics developed HUS (p = 0.12). Microbiological testing showed all E. coli O104:H4 to be extended-spectrum beta lactamase producers and thus susceptible only to fluoroquinolones, aminoglycosides and carbapenems. Two of the five patients (40 %) treated with ciprofloxacin and 17 of the 19 patients (89 %) treated without ciprofloxacin developed HUS (p = 0.043). CONCLUSION: In our E. coli O104:H4-infected patients, treatment of diarrhea with antibiotics did not increase the risk of HUS. Significantly fewer patients treated with ciprofloxacin developed HUS than patients who did not receive ciprofloxacin.

Low-grade infection after a total knee arthroplasty caused by Actinomyces naeslundii.

Here, we present a case of an 85-year-old woman with a low-grade-infection caused by Actinomyces naeslundii after total-knee arthroplasty (TKA) followed by septic loosening. Actinomyces naeslundii was cultured from a tissue sample from the knee joint capsule/synovial tissue obtained after the initial TKA. A review of the literature revealed two cases of periprosthetic infection and another three cases of arthritis due to Actinomyces naeslundii. So far, no standard treatment for periprosthetic infections caused by Actinomyces species has been established.

Evaluation of antimicrobial effects of novel implant materials by testing the prevention of biofilm formation using a simple small scale medium-throughput growth inhibition assay.

Staphylococcal colonization of implants is a serious complication of orthopaedic surgery. Anti-infectious modification of implant surfaces may serve to prevent bacterial colonization. The authors set out to develop an in vitro test system for the analysis of prevention of biofilm formation by Staphylococcus epidermidis and Staphylococcus aureus on implant materials. Biofilm growth was monitored over 10 days on titanium disks in order to develop appropriate test parameters. Bacterial cell counts following ultrasonic treatment of the colonized samples were compared with scanning electron microscope images of the specimens. Copper ion containing surfaces (ie copper [Cu] and inter-metallic Ti-Cu films) were used for growth inhibition assays: copper ion releasing specimens led to reduced bacterial numbers in biofilms and decreased bacterial persistence in the model used. The assay used represents an inexpensive and quick in vitro screen for the antibacterial effects of novel implant surface materials.

The current role of pulsed-field gel electrophoresis in methicillin-resistant Staphylococcus aureus (MRSA) typing and the retrospective identification of outbreaks.

The objective of this paper was to investigate whether retrospective pulsed-field gel electrophoresis (PFGE) of methicillin-resistant Staphylococcus aureus (MRSA) isolates at two-year intervals is suitable and sufficient to demonstrate changes in the clonal composition of MRSA isolates and to identify previously undetected local outbreaks. PFGE patterns of 400 MRSA isolates were collected between 2004 and 2008 at the University of Rostock Hospital in Germany, and were used to assess the prevalence of MRSA clones at different time points. Only minor changes were detected. The combined analysis of all isolates that were collected per year reduced the time needed to perform this laborious procedure. The retrospective identification of outbreaks may require shorter intervals. Improved infection prevention and control measures prevented further outbreaks in previously affected hospital departments. In conclusion, PGFE at two-year intervals is sufficient to detect changes in the clonal composition of local MRSA isolates. If time for identification is important during outbreak investigations, more rapid methods with a similarly high discriminatory power such as spa typing should be used.

[Prophylaxis against infections after needle stick injuries]. / Infektionsprophylaxe nach Nadelstichverletzung.

BACKGROUND: Needle stick injuries are associated with a risk of infection. The aim of this study was to collate the reasons for the failure to carry out prophylactic measures from the perspective of those affected. METHODS: An anonymous internet questionnaire was designed to record the experiences of health care workers at the University Hospital Rostock with secondary infection prophylaxis after needle stick injuries. RESULTS: During the investigation period 106 questionnaires were returned. There were deficiencies in the acceptance of prophylactic measures due to job-associated lack of time and social pressure. CONCLUSION: The study suggests reorganization of work-flows and additional educational measures about the necessity of prophylactic procedures after needle stick injuries.

Bartonella quintana endocarditis of the tricuspid and mitral valves.

Bartonella quintana is a gram-negative microorganism that can lead to culture-negative infective endocarditis (IE) in immunocompromised patients. Here, we present an exceptionally rare case of a 70-year-old male with Bartonella quintana-associated IE primarily limited to the tricuspid valve that spread to the mitral valve after tricuspid valve replacement. This was then complicated by infective spondylodiscitis of the thoracic vertebrae, ultimately resulting in death due to cardiac arrest.

[Periprosthetic infections following total hip replacement with ESBL-forming bacteria: importance for clinical practice]. / Periprothetische Infektionen nach Hüfttotalendoprothese mit ESBL-bildenden Bakterien: Bedeutung für die klinische Praxis.

Implant infections remain feared and severe complications after total hip replacement. An even higher rate of periprosthetic infections can be observed after revision surgery in comparison to primary total hip replacement. An additional threat for patients with artificial joints arises from the fact that bacteria resistant to a multitude of antibiotics are encountered with increasing frequency in the hospital setting.Among these the enterobacteria producing extended spectrum ß-lactamases (ESBL) are the second most frequent group of multiresistant pathogens. ESBLs are enzymes which possess the ability to hydrolyse third and fourth generation cephalosporins resulting in a distinctive resistance against these antibiotics. Even though ESBLs were first described in the early 1980's and now represent pathogens of utmost importance in intensive care units, they have been hardly considered in orthopedic and trauma surgery.In the present manuscript we provide an overview of the epidemiology and diagnostics of ESBL-expressing bacteria and demonstrate the difficulties in managing implant-associated infections with resistant bacteria. Furthermore, we emphasize the importance of recognizing ESBL-positive bacteria as increasingly important pathogens which require special precautions and treatment. Clinical evaluations suggest that ESBLs in orthopedic and trauma surgery are not a rare phenomenon any more.

[Management of an Outbreak with Cases of Nosocomial Pneumonia Caused by a Novel Multi-Drug-Resistant Acinetobacter baumannii Clone]. / Management eines Ausbruchs nosokomialer Pneumonien durch einen neuen multiresistenten Acinetobacter baumannii-Klon1.

We describe the detection and investigation of an outbreak involving a multi-drug-resistant acinetobacter (A.) baumannii clone in the neurological intensive care unit (ICU) at the University hospital Rostock (Germany). The bacteria were isolated from 7 ICU patients within 20 weeks, six of them showing signs of pneumonia. Among 24 tested antibiotics, the isolates were only susceptible to colistin. An epidemiological investigation revealed the presence of multi-drug-resistant A. BAUMANNII isolates in 13 of 37 samples from medical devices, patient-associated objects and room equipment from the patients' environment. When investigating the source of this strain in our hospital, we found that it first appeared three years before. Since then it has caused sporadic infections in the medical and neurological ICUs prior to the presented outbreak. The identity of all isolated strains with the novel clone was demonstrated with pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). A multimodal intervention program was introduced by the hygiene staff on the affected ICU. It included consequent enforcement of standard hygiene precautions, repeated staff education and elaborated disinfection protocols specifically addressing the patients' environment. The procedures led to cessation of A. baumannii detection in environmental samples. Thereafter, the outbreak was cleared within 20 weeks.

[Antibiotic prophylaxis for patients with joint prostheses undergoing dental treatment--a topic for discussion]. / Infektionsprophylaxe für Gelenkprothesenträger bei zahnärztlichen Behandlungen--ein Diskussionsbeitrag.

AIM: In accordance with international guidelines, the German Society for Cardiology and the Paul Ehrlich Society for Chemotherapy recently adapted their recommendations for antibiotic prophylaxis of infectious endocarditis. The new version reflected the statistically lower risk for such infections as compared to former considerations and reduced the group of patients who would benefit from the prophylaxis. That paper as well as an increasing number of statements of orthopaedic/traumatologic or dental societies stimulated our contribution on the prevention of prosthesis infections after dental care. With this article we intend to stimulate a position paper of the German Society for Orthopaedics and Traumatology. METHOD: For our study we screened the international literature on the association between bacteremia and dental treatment, bacteremia and prosthesis infections as well as on the availability and risks of antibiotic prophylaxis for prosthesis infections. In addition, we included data on the responsible microorganisms and the importance of biofilms both in the oral cavity and on the infected prosthesis. RESULTS: Generally, the risk of prosthesis infections after bacteremia is lower than that of endocarditis. Also, the range of involved microorganisms only partially overlaps in both diseases. Of note, bacteremia regularly occurs due to normal dental hygiene measures or even after chewing. Because of this high background risk and because of the extended latency period between dental care and symptomatic prosthesis infections, the causality of professional dental measures for prosthesis infections has never conclusively been demonstrated, e.g., by employing molecular methods. However, the association remains plausible and the consequences for such patients are severe. CONCLUSION: We suggest an oral prophylaxis with an aminopenicillin plus beta-lactamase inhibitor or clindamycin shortly before and 4 hours after dental care depending on the tissue invasiveness of the dental measures and the personal risk profile of the patient (prosthesis recently implanted, history of prosthesis infection, natural or iatrogenic conditions severely affecting the immune status).

[Recurrent tonsillopharyngitis associated with Burkholderia cenocepacia : two case reports]. / Chronisch rezidivierende Tonsillopharyngitis infolge einer Burkholderia-cenocepacia-Infektion : 2 Fallberichte.

The Burkholderia cepacia complex comprises bacteria typically responsible for respiratory infections in immunocompromised and cystic fibrosis patients. However, these bacteria are rarely associated with infections in immunocompetent patients. In the presented case reports of two nonhospitalized immunocompetent female patients who underwent tonsillectomy as the ultimate therapy for recurrent tonsillopharyngitis, Burkholderia cenocepacia were demonstrated in the surgically removed tonsils. The clinical, histological, and microbiological findings of both cases are presented. The etiological relevance and the probable success of antibiotic treatment versus surgical measures are discussed.