Colonization by Staphylococcus species resistant to methicillin or quinolone on hands of medical personnel in a skilled-nursing facility

Bacterial growth and recovery on hospital biometric devices: effect of two types of disinfectants

Objectives:

The aim of the study was to evaluate the presence of bacterial contamination on biometric identification devices in a public hospital; identify the species of bacteria implicated in the contamination and assess bacterial recovery after the use of 2 types of disinfectants: alcohol 70% and isopropyl alcohol chlorhexidine.

Design:

Before and after trial.

Setting:

Public hospital, tertiary referral center.

Participants:

All existing biometric identification devices in the hospital (n = 20).

Methods:

Collection of 2 microbiological samples from the fingerprint reading surface of biometric devices immediately before and after applying the solution with alcohol 70% and in separate time periods with isopropyl alcohol chlorhexidine.

Results:

It have been identified 21 different bacterial species in a total of 78 samples, mostly Staphylococcus epidermidis (32 samples) and S aureus (7 samples). S epidermidis was eliminated in 61.5% of the samples after disinfecting with alcohol 70% and in 92.3% of the samples disinfected with isopropyl alcohol chlorhexidine. S aureus was eliminated in 33.3% and 100% of the samples, respectively. We found no bacterial growth in 10% of the devices after disinfection with 70% alcohol and in 78.9% of devices after disinfection with isopropyl alcohol chlorhexidine. We also found that there was a decrease in the frequency of species isolated after using both disinfection solutions, although isopropyl alcohol chlorhexidine appeared to be more effective.

Conclusions:

The biometric identification devices used in this hospital seem to be safe regardless of the products used for its cleaning. The majority of the bacteria found are commensal skin microorganisms. We did not find pathogenic bacteria for immunocompetent individuals, in particular methicillin-resistant S aureus.

How often are health care personnel hands colonized with multidrug- resistant organisms? A systematic review and meta-analysis

BACKGROUND

Hands of health care personnel (HCP) can transmit multidrug-resistant organisms (MDROs), resulting in infections. Our aim was to determine MDRO prevalence on HCP hands in adult acute care and nursing facility settings.

METHODS

A systematic search of PubMed/MEDLINE, Web of Science, CINAHL, Embase, and Cochrane CENTRAL was performed. Studies were included if they reported microbiologic culture results following HCP hands sampling; included prevalent MDROs, such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus, Clostridium difficile, Acinetobacter baumannii, or Pseudomonas aeruginosa, and were conducted in acute care or nursing facility settings.

RESULTS

Fifty-nine articles comprising 6,840 hand cultures were included. Pooled prevalence for MRSA, P aeruginosa, A baumannii, and vancomycin-resistant Enterococcus were 4.26%, 4.59%, 6.18%, and 9.03%, respectively. Substantial heterogeneity in rates of pathogen isolation were observed across studies (I² = 81%-95%). Only 4 of 59 studies sampled for C difficile, with 2 of 4 finding no growth. Subgroup analysis of MRSA revealed the highest HCP hand contamination rates in North America (8.28%). Sample collection methods used were comparable for MRSA isolation (4%-7%) except for agar direct contact (1.55%).

CONCLUSIONS

Prevalence of common MDROs on HCP hands vary by pathogen, care setting, culture acquisition method, study design, and geography. When obtained at an institutional level, these prevalence data can be utilized to enhance knowledge, practice, and research to prevent health care-associated infections.

Coagulase-negative staphylococcal skin carriage among neonatal intensive care unit personnel: from population to infection

Coagulase-negative staphylococci (CoNS) are a major cause of sepsis in neonatal intensive care units (NICU) worldwide. Infecting strains of these commensal bacteria may originate from NICU personnel. Therefore, we studied the characteristics of CoNS isolates from NICU personnel and compared them to those of isolates from the general population and from sepsis patients. Furthermore, we studied the epidemiological effect on CoNS carriage of NICU personnel after a period of absence. In our study, we isolated CoNS from the thumbs of NICU personnel every 2 weeks during the summer of 2005 and sampled personnel returning from vacation and a control group from the general population. Furthermore, we collected sepsis isolates from this period. Isolates were tested for antibiotic resistance, mecA and icaA carriage, biofilm production, and genetic relatedness. We found that mecA and icaA carriage as well as penicillin, oxacillin, and gentamicin resistance were significantly more prevalent in CoNS strains from NICU personnel than in community isolates. Similar trends were observed when postvacation strains were compared to prevacation strains. Furthermore, genetic analysis showed that 90% of the blood isolates were closely related to strains found on the hands of NICU personnel. Our findings revealed that CoNS carried by NICU personnel differ from those in the general population. Hospital strains are replaced by community CoNS after a period of absence. NICU personnel are a likely cause for the cross-contamination of virulent CoNS that originate from the NICU to patients.

Antimicrobial resistance patterns of colonizing flora on nurses' hands in the neonatal intensive care unit

BACKGROUND

The Centers for Disease Control and Prevention recommends the use of an alcohol-based handrub for health care worker hand hygiene. The purpose of this study was to examine effects of hand hygiene product and skin condition on the antimicrobial resistance patterns of colonizing hand flora among nurses.

METHODS

Colonizing hand flora of 119 nurses working in 2 neonatal intensive care units was compared during a 22-month crossover study using alcohol handrub or antiseptic soap.

RESULTS

Altogether, 1442 isolates from 834 hand cultures (mean, 7 cultures/nurse) were obtained. In 3 of 9 regression analyses modeling for resistant staphylococcal flora, the use of antiseptic soap was a significant predictor of resistance, and nurses with damaged skin were 2.79 times more likely to carry Staphylococcus warneri isolates resistant to gentamicin.

CONCLUSION

Hand hygiene product and skin condition may influence resistance patterns of hand flora of care providers.

Prevalence and clinical relevance of Staphylococcus warneri in the neonatal intensive care unit

OBJECTIVE

To describe the prevalence of Staphylococcus warneri on the hands of nurses and the clinical relevance of this organism among neonates in the neonatal intensive care unit (NICU).

DESIGN

Prospective cohort study that examined the microbial flora on the hands of nurses and clinical isolates recovered from neonates during a 23-month period (March 1, 2001, through January 31, 2003).

SETTING

Two high-risk NICUs in New York City.

PARTICIPANTS

All neonates hospitalized in the NICUs for more than 24 hours and all full-time nurses from the same NICUs who volunteered to participate.

INTERVENTION

At baseline and then every 3 months, samples for culture were obtained from each nurse's cleaned dominant hand. Pulsed-field electrophoresis compared S. warneri isolates from neonates and staff.

RESULTS

Samples for culture (n=834) were obtained from the hands of 119 nurses; 520 (44%) of the 1,195 isolates of coagulase-negative staphylococci recovered were identified as S. warneri. Of the 647 clinically relevant isolates recovered from neonates, 17 (8%) of the 202 isolates that were identified to species level were S. warneri. Pulsed-field electrophoresis revealed a common strain of S. warneri that was shared among the nurses and neonates. Furthermore, 117 (23%) of 520 S. warneri isolates from nurses' hands had minimum inhibitory concentrations for vancomycin of 4 mu g/mL, which indicate decreasing susceptibility.

CONCLUSIONS

Our findings that S. warneri can be pathogenic in neonates, is a predominant species of coagulase-negative staphylococci cultured from the hands of nurses, and has decreased vancomycin susceptibility underscore the importance of continued surveillance for vancomycin resistance and pathogenicity in pediatric care settings.

Molecular epidemiology of clinical and carrier strains of methicillin resistant Staphylococcus aureus (MRSA) in the hospital settings of north India

BACKGROUND

The study was conducted between 2000 and 2003 on 750 human subjects, yielding 850 strains of staphylococci from clinical specimens (575), nasal cultures of hospitalized patients (100) and eye & nasal sources of hospital workers (50 & 125 respectively) in order to determine their epidemiology, acquisition and dissemination of resistance genes.

METHODS

Organisms from clinical samples were isolated, cultured and identified as per the standard routine procedures. Susceptibility was measured by the agar diffusion method, as recommended by the National Committee for Clinical Laboratory Standards (NCCLS). The modified method of Birnboin and Takahashi was used for isolation of plasmids from staphylococci. Pulsed-field gel electrophoresis (PFGE) typing of clinical and carrier Methicillin resistant Staphylococcus aureus (MRSA) strains isolated during our study was performed as described previously.

RESULTS

It was shown that 35.1% of Staphylococcus aureus and 22.5% of coagulase-negative staphylococcal isolates were resistant to methicillin. Highest percentage of MRSA (35.5%) was found in pus specimens (n = 151). The multiple drug resistance of all MRSA (n = 180) and Methicillin resistant Coagulase-negative Staphylococcus aureus (MRCNS) (n = 76) isolates was detected. In case of both methicillin-resistant as well as methicillin-sensitive Saphylococcal isolates zero resistance was found to vancomycin where as highest resistance was found to penicillin G followed by ampicillin. It was shown that the major reservoir of methicillin resistant staphylococci in hospitals are colonized/infected inpatients and colonized hospital workers, with carriers at risk for developing endogenous infection or transmitting infection to health care workers and patients. The results were confirmed by molecular typing using PFGE by SmaI-digestion. It was shown that the resistant markers G and T got transferred from clinical S. aureus (JS-105) to carrier S. aureus (JN-49) and the ciprofloxacin (Cf) and erythromycin (E) resistance seemed to be chromosomal mediated. In one of the experiments, plasmid pJMR1O from Staphylococcus aureus coding for ampicillin (A), gentamicin (G) and amikacin (Ak) resistance was transformed into Escherichia coli. The minimal inhibitory concentrations (MICs) for A and G were lower in E. coli than in S. aureus. However, the MIC for Ak was higher in E. coli transformants than in S. aureus.

CONCLUSION

There is a progressive increase in MRSA prevalence and multi-drug resistance in staphylococci. Vancomycin is still the drug of choice for MRSA infections. The major reservoir of methicillin resistant staphylococci in hospitals is colonized/infected inpatients and colonized hospital workers. Resistance transfer from staphylococci to E. coli as well as from clinical to carrier staphylococci due to antibiotic stress seemed to be an alarming threat to antimicrobial chemotherapy.

Epidemiologic background of hand hygiene and evaluation of the most important agents for scrubs and rubs

The etiology of nosocomial infections, the frequency of contaminated hands with the different nosocomial pathogens, and the role of health care workers' hands during outbreaks suggest that a hand hygiene preparation should at least have activity against bacteria, yeasts, and coated viruses. The importance of efficacy in choosing the right hand hygiene product is reflected in the new Centers for Disease Control and Prevention guideline on hand hygiene (J. M. Boyce and D. Pittet, Morb. Mortal. Wkly. Rep. 51:1-45, 2002). The best antimicrobial efficacy can be achieved with ethanol (60 to 85%), isopropanol (60 to 80%), and n-propanol (60 to 80%). The activity is broad and immediate. Ethanol at high concentrations (e.g., 95%) is the most effective treatment against naked viruses, whereas n-propanol seems to be more effective against the resident bacterial flora. The combination of alcohols may have a synergistic effect. The antimicrobial efficacy of chlorhexidine (2 to 4%) and triclosan (1 to 2%) is both lower and slower. Additionally, both agents have a risk of bacterial resistance, which is higher for chlorhexidine than triclosan. Their activity is often supported by the mechanical removal of pathogens during hand washing. Taking the antimicrobial efficacy and the mechanical removal together, they are still less effective than the alcohols. Plain soap and water has the lowest efficacy of all. In the new Centers for Disease Control and Prevention guideline, promotion of alcohol-based hand rubs containing various emollients instead of irritating soaps and detergents is one strategy to reduce skin damage, dryness, and irritation. Irritant contact dermatitis is highest with preparations containing 4% chlorhexidine gluconate, less frequent with nonantimicrobial soaps and preparations containing lower concentrations of chlorhexidine gluconate, and lowest with well-formulated alcohol-based hand rubs containing emollients and other skin conditioners. Too few published data from comparative trials are available to reliably rank triclosan. Personnel should be reminded that it is neither necessary nor recommended to routinely wash hands after each application of an alcohol-based hand rub. Long-lasting improvement of compliance with hand hygiene protocols can be successful if an effective and accessible alcohol-based hand rub with a proven dermal tolerance and an excellent user acceptability is supplied, accompanied by education of health care workers and promotion of the use of the product.

Emergence of resistant staphylococci on the hands of new graduate nurses

OBJECTIVE

To describe the aerobic microbial flora on the hands of experienced and new graduate nurses over time.

DESIGN

A prospective cohort design that examined the relationship between duration of employment in an intensive care unit (ICU) and the microbial flora on the hands of experienced and new graduate nurses during a 23-month period.

SETTING

A 50-bed, level III-IV neonatal ICU in New York City.

PARTICIPANTS

Twelve experienced nurses and 9 new graduate nurses working full time in the NICU.

INTERVENTION

One hundred fifty samples were obtained from the clean, dominant hands of the nurses. Cultures were performed at baseline and then quarterly for each experienced and new graduate nurse. Baseline and final cultures of Staphylococcus epidermidis were further examined using pulsed-field gel electrophoresis.

RESULTS

At baseline, a significantly larger proportion of the experienced nurses had methicillin-resistant, coagulase-negative staphylococci isolated from their hands compared with the new graduate nurses (95% and 33%, respectively; P = .0004). For a second culture, performed 1 to 4 months later, there were no longer significant differences between the two groups (82% and 54%, respectively; P = .12). By the last culture, all staphylococcal isolates were methicillin resistant in both groups of nurses; 3 were methicillin-resistant S. aureus.

CONCLUSIONS

Colonization with methicillin-resistant staphylococci occurred after brief exposure to the hospital environment, despite the use of antiseptic hand hygiene agents. Furthermore, at final culture, the two groups shared one dominant hospital-acquired strain of S. epidermidis.

Antibacterial activity of vegetables and juices

OBJECTIVE

We evaluated the antibacterial activities of various fruit and vegetable extracts on common potential pathogens including antibiotic-resistant strains.

METHODS

Standardized bacterial inocula were added to serial dilutions of sterile vegetable and fruit extracts in broth, with final bacterial concentrations of 10(4-5) cells/mL. After overnight incubation at 35 degrees C, antibacterial activity was measured by minimum inhibitory and minimum bactericidal dilutions (for raw juices) or concentrations (for tea).

RESULTS

Among the vegetable and fruit extracts tested, all green vegetables showed no antibacterial activity on Staphylococcus epidermidis and Klebsiella pneumoniae. All purple and red vegetable and fruit juices had antibacterial activities in dilutions ranging from 1:2 to 1:16. Garlic juice had significant activity, with bactericidal action in dilutions ranging up to 1:128 of the original juice. Tea also had significant activity, with bactericidal action in concentrations ranging up to 1.6 mg/mL, against a spectrum of pathogens including resistant strains such as methicillin- and ciprofloxacin-resistant staphylococci, vancomycin-resistant enterococci, and ciprofloxacin-resistant Pseudomonas aeruginosa.

CONCLUSIONS

Tea and garlic have the potential for exploration of broader applications as antibacterial agents.

A comparison of the bacteria found on the hands of 'homemakers' and neonatal intensive care unit nurses

This prevalence study was conducted to compare the counts, types and antimicrobial resistance profiles of bacterial flora on the hands of individuals in the community to that of nurses at a nearby university teaching hospital, with an intense hand hygiene regimen. Hand cultures were obtained from 204 individuals during a home visit and 119 nurses in two neonatal intensive care units (NICUs). The mean total log counts of organisms were 5.73 and 5.24 for the homemakers [defined as the person (usually the mother) who is the primary person responsible for arranging childcare, cooking, cleaning etc] and nurse hands, respectively (P<0.0001). Significantly more homemakers had Acinetobacter lwoffii, Enterobacter cloacae, Klebsiella pneumoniae, Pseudomonas aeruginosa, P. fluorescens/putida, and Staphylococcus aureus on their hands compared with the nurses (all P<0.05). However, significantly more nurses had Enterococcus faecalis, S. epidermidis, and S. warneri on their hands (P<0.05). Of note, the hands of nurses harboured significantly more S. epidermidis strains resistant to amoxicillin/clavulanate, cefazolin, clindamycin, erythromycin, and oxacillin and S. warneri resistant to amoxicillin/clavulanate, cefazolin, clindamycin, and oxacillin (P<0.05). Surprisingly, significantly more trimethoprim/sulfamethoxazole-resistant S. epidermidis and ciprofloxacin-resistant S. warneri was recovered from the hands of homemakers (P<0.05). This study demonstrates differences in prevalence, bacterial composition and antimicrobial resistance of hand flora of hospital personnel compared with homemakers. Moreover, the hands of homemakers may serve as community reservoirs for antimicrobial resistant strains of clinical importance.

Microbial flora of hands of homemakers

OBJECTIVES AND METHODS

Because of increasing concern about antimicrobial resistance in the community, aerobic flora of hands of 224 healthy homemakers in northern Manhattan, New York, were examined.

RESULTS

Mean log colony-forming unit counts before and after handwashing were 5.72 and 5.69, respectively, P =.60; mean number of species identified/sample was 3.6 before washing and 3.3 after (P =.02). After handwashing gram-negative bacteria were isolated from 75.1% of subjects; yeast from 32.9%; and Staphylococcus aureus from 18.5%, 1 of which (2.4%) was oxacillin-resistant. Generally, these community isolates were more sensitive than isolates from inpatients in the local hospital, although community isolates of Pseudomonas aeruginosa were significantly more resistant than inpatient isolates for 4/10 agents tested.

CONCLUSIONS

Hands of healthy persons in the community were usually colonized with gram-negative bacteria, a single handwash had little impact on microbial counts, and hands of healthy adults may increasingly become one reservoir for antimicrobial resistance.

Rapid PCR detection of the methicillin resistance gene, mecA, on the hands of medical and non-medical personnel and healthy children and on surfaces in a neonatal intensive care unit

The hands of medical personnel are the chief vectors for transmission of antibiotic-resistant bacteria and probably serve as an important reservoir for antibiotic resistance genes in hospitals. In this survey we examined different reservoirs of the methicillin resistance gene, mecA, using a simplified PCR method. Samples (n = 151) were taken from the hands of medical and non-medical personnel and healthy children and from surfaces in a neonatal intensive care unit (NICU). We also performed sampling from 4 different body sites in 5 of the medical personnel. Fifteen out of 16 nurses (94%) from the ICU carried the mecA gene on their hands, whereas only 35% of the paediatric nurses were mecA-positive. Of all medical personnel, 44% carried the mecA gene on their hands. There was a significant difference (p < 0.015) between medical and non-medical personnel in terms of the carriage rate of mecA. Four samples from surfaces in a NICU--2 ventilators, 1 bench and 1 telephone--were positive for mecA. Our results are comparable with those from previous studies on reservoirs of methicillin-resistant coagulase-negative staphylococci using conventional culture techniques.

Nasal colonization by methicillin-resistant coagulase-negative staphylococcus in community skilled nursing facility patients

BACKGROUND

Methicillin-resistant coagulase-negative staphylococci (MRCNS) are increasing nosocomial pathogens in acute care hospital patients. However, there is little information on the epidemiology of MRCNS in skilled nursing facilities (SNFs). We report a pilot survey of the prevalence of MRCNS colonization in SNF patients.

METHODS

Anterior nasal swabs were plated on oxacillin salt screening agar for selection of MRCNS. Suspected MRCNS were confirmed by coagulase and catalase tests and standard disc-diffusion antimicrobial susceptibility tests.

RESULTS

The overall prevalence of MRCNS was 40% for in-house continuing SNF patients, 49% for newly admitted patients, and 60% for SNF nursing personnel. The prevalence was 13% in a "control" group of nonmedical personnel. Forty-six percent of MRCNS were resistant to ciprofloxacin. The frequency of colonization with MRCNS increased over time. After an average 17 months of facility stay, 32% of noncarriers acquired MRCNS. High frequency of colonization was associated with greater disability.

CONCLUSION

Colonization with MRCNS is common among SNF patients, who can serve as a reservoir for transfer of such strains to acute care hospitals. Careful infection control practice, including judicious use of antibiotics with frequent handwashing, will remain critical policies for limiting spread of such strains.

Ciprofloxacin. An updated review of its pharmacology, therapeutic efficacy and tolerability

Ciprofloxacin is a broad spectrum fluoroquinolone antibacterial agent. Since its introduction in the 1980s, most Gram-negative bacteria have remained highly susceptible to this agent in vitro; Gram-positive bacteria are generally susceptible or moderately susceptible. Ciprofloxacin attains therapeutic concentrations in most tissues and body fluids. The results of clinical trials with ciprofloxacin have confirmed its clinical efficacy and low potential for adverse effects. Ciprofloxacin is effective in the treatment of a wide variety of infections, particularly those caused by Gram-negative pathogens. These include complicated urinary tract infections, sexually transmitted diseases (gonorrhoea and chancroid), skin and bone infections, gastrointestinal infections caused by multiresistant organisms, lower respiratory tract infections (including those in patients with cystic fibrosis), febrile neutropenia (combined with an agent which possesses good activity against Gram-positive bacteria), intra-abdominal infections (combined with an antianaerobic agent) and malignant external otitis. Ciprofloxacin should not be considered a first-line empirical therapy for respiratory tract infections if penicillin-susceptible Streptococcus pneumoniae is the primary pathogen; however, it is an appropriate treatment option in patients with mixed infections (where S. pneumoniae may or may not be present) or in patients with predisposing factors for Gram-negative infections. Clinically important drug interactions involving ciprofloxacin are well documented and avoidable with conscientious prescribing. Recommended dosage adjustments in patients with impaired renal function vary between countries; major adjustments are not required until the estimated creatinine clearance is < 30 ml/min/1.73m2 (or when the serum creatinine level is > or = 2 mg/dl). Ciprofloxacin is one of the few broad spectrum antibacterials available in both intravenous and oral formulations. In this respect, it offers the potential for cost savings with sequential intravenous and oral therapy in appropriately selected patients and may allow early discharge from hospital in some instances. In conclusion, ciprofloxacin has retained its excellent activity against most Gram-negative bacteria, and fulfilled its potential as an important antibacterial drug in the treatment of a wide range of infections. Rational prescribing will help to ensure the continued clinical usefulness of this valuable antimicrobial drug.

Infections and antibiotic resistance in nursing homes

Infections occur frequently in nursing home residents. The most common infections are pneumonia, urinary tract infection, and skin and soft tissue infection. Aging-associated physiologic and pathologic changes, functional disability, institutionalization, and invasive devices all contribute to the high occurrence of infection. Antimicrobial agent use in nursing homes is intense and usually empiric. All of these factors contribute to the increasing frequency of antimicrobial agent-resistant organisms in nursing homes. Programs that will limit the emergence and impact of antimicrobial resistance and infections in nursing homes need to be developed.