Microbiologic survey of long-term care facilities

The Clinical Profile of Patients With Culture-Positive Urinary Tract Infections Admitting to a Tertiary Hospital in Sri Lanka

Introduction Urinary tract infections (UTIs) are globally prevalent. This study explores the clinical and pathological profile of culture-positive UTI patients at Sri Jayewardenepura General Hospital. Method In this descriptive cross-sectional study conducted at Sri Jayewardenepura General Hospital from December 2020 to May 2021, we evaluated patients over 14 years with positive urine culture reports. Excluding those with HIV, undergoing chemotherapy, or pregnant, we used consecutive sampling. Data were collected via interviewer-administered questionnaires and analyzed using SPSS version 21.0 (IBM Inc., Armonk, New York), employing descriptive statistics and Fisher's exact tests to identify factors associated with urinary tract infections. Results The study involved approximately 278 participants. The mean age remained 60 ± 20.279 years, with over half of the participants being female. Common symptoms like fever and lower abdominal pain were observed in 22.30% of cases. The incidence of acute kidney injury was 30.58%. Escherichia coli (36%) and Klebsiella pneumoniae (26%) were the predominant organisms found. Indwelling catheters and other urinary tract conditions were considered risk factors. Patients with at least one risk factor were more likely to receive antibiotics before the urine culture. Similarly, males exhibited a higher prevalence of at least a risk factor than females. Conclusion UTIs are a significant clinical issue in older populations, with females being more susceptible. Fever and abdominal pain were common symptoms. Escherichia coli and Klebsiella pneumoniae were the most frequent causative agents. Further research is necessary to identify risk factors and predictors of antimicrobial resistance in UTI patients.

Incidence and Outcomes of Staphylococcus aureus Bacteriuria: A Population-based Study

BACKGROUND

Staphylococcus aureus bacteriuria (SABU) may represent multiple processes ranging from asymptomatic colonization to a marker of S. aureus bacteremia (SAB). Our objective was to describe SABU at a population-based level and determine patient characteristics associated with SAB.

METHODS

A retrospective study was performed using electronic databases. All urine cultures positive for S. aureus between 2010 and 2013 within the Calgary Health Zone were included. Patient characteristics were compared among patients with and without SAB and risk factors identified using multiple logistic regression modeling.

RESULTS

A total of 2540 urine cultures positive for S. aureus from 2054 patients were analyzed. The incidence of SABU was greatest among geriatric males with multiple comorbidities. SAB occurred in 175 (6.9%) of SABU patients. Those with SAB were more likely to be hospitalized, male, have a recent urinary procedure, have pure S. aureus culture in urine, and have laboratory findings suggesting systemic infection. Patients with isolated SABU were more likely to be ≥65 years, have dementia, and have abnormal urinalyses with pyuria and urine nitrites. In-hospital mortality in patients with SABU and SABU+SAB was 9.2% and 17.5%, respectively. Patients with SABU detected ≥48 hours before SAB had the highest risk of death.

CONCLUSIONS

Less than 7% of patients with SABU have or will develop SAB. Characteristics associated with SABU were identified that established higher risk for systemic infection. Investigating SABU patients with these characteristics for systemic infection is warranted because a delay in diagnosis is associated with increased mortality.

Breaking the Chain of Infection in Older Adults: A Review of Risk Factors and Strategies for Preventing Device-Related Infections

Device-related infections (DRIs) are a significant cause of morbidity and mortality among older adults. Indwelling devices (urinary catheters, percutaneous feeding tubes, and central venous catheters) are frequently used in this vulnerable population. Indwelling devices provide a portal of entry for pathogenic organisms to invade a susceptible host and cause infection and are an important target for infection prevention and antimicrobial stewardship efforts. Within the "Chain of Infection" that leads to DRIs in older adults, multiple opportunities exist to implement interventions that "break the links" and reduce colonization with multidrug-resistant organisms, reduce infections, and improve antimicrobial use.

Nursing Home-Acquired Bloodstream Infection

Objectives:

This article reviews published studies of nursing home-acquired BSI in North America to determine whether there have been changes in the epidemiology of this infection in the past 20 years and to define indications for blood cultures in the nursing home setting.

Methods:

A Medline search was conducted for the period from 1980 to August 2003.

Results:

Seven studies of nursing home-acquired BSI were identified. The incidence of nursing home-acquired BSI was low (0.3 episode per 1,000 resident care-days). Sources of BSI changed little during the past two decades, with urinary tract infection representing approximately 50% of the episodes. The bacteriology also did not change substantially during the past 20 years; gram-negative bacilli were isolated in approximately 50% of the episodes and Escherichia coli was the most commonly isolated organism. In the most recent study, covering the period 1997-2000, resistance to fluoroquinolones and broad-spectrum penicillins and cephalosporins was uncommon among gram-negative blood isolates; MRSA was the most common resistant organism causing nursing home-acquired BSI. Case-fatality rates changed little during the past 20 years; urinary tract infection was associated with the lowest mortality and pneumonia had the highest case-fatality rate.

Conclusion:

There has been little change in the epidemiology of nursing home-acquired BSI in the past 20 years. Given the low incidence of BSI and the low overall yield of positive results of blood cultures (probably ≤ 6%), there is currently no support for the routine use of blood cultures in the nursing home setting.

[Healthcare-associated infections and antimicrobial use in long term care facilities (HALT-2): German results of the second European prevalence survey]

Prevention of infections and strategies for the prudent use of antimicrobials in long-term care facilities have gained importance in view of the demographic changes, not only in Germany. To generate appropriate data and to identify relevant aspects of infection prevention in this field, the European Centre for Disease Prevention and Control (ECDC) launched the second point prevalence survey of healthcare-associated infections and antimicrobial use in European long-term care facilities in 2013 (HALT-2). Despite methodical adjustments in the collection of data on healthcare-associated infections, in this second survey healthcare workers in the participating facilities were intensively trained in methodology and data collection. Overall, 221 German facilities participated and collected data from 17,208 residents. Well-established structures of regional networks facilitated the recruitment of participants as well as the preparations for training and survey. The median prevalence of residents receiving at least one antimicrobial agent was 1.1% (95 %-CI 0,7-1,6)), which is remarkably low. However, the most frequently used antimicrobials in German facilities beside beta-lactams (penicillins 18.2%, other beta-lactams 17.2%) were quinolones (28.2%). Data collection of infections was performed based on signs and symptoms in detailed decision algorithms according to the recently updated McGeer surveillance criteria and yielded a median prevalence of 1.7% (95 %-CI 1,1-2,2). Symptomatic urinary tract infections (28.4%), skin and soft tissue infection (27.9%), and respiratory tract infections (24.7%) were identified both as the most common types of infections and the most common indications for the use of systemic antimicrobials. Clinical implications evolve mainly from the high use of quinolones. In terms of infection prevention measures, compliance of health care workers with a hand hygiene regimen revealed further potential for improvement.

Prevention of infections in nursing homes: antibiotic prophylaxis versus infection control and antimicrobial stewardship measures

Because of the lack of structural and human resources for implementing more effective and safe preventive procedures, antimicrobial prophylaxis is often used to prevent infections in nursing homes. However, if data on the efficacy of antibiotic prophylaxis in nursing homes are null, there is a plenty of evidence that the inappropriate use of antimicrobials in this setting is associated with a high rate of colonization and infection with multi-drug-resistant organisms (MDROs), and of Clostridium difficile infection (CDI). Here, we have reviewed the infection epidemiology, the burden of MDROs and CDI, the antibiotic use and some potential infection preventive measures in nursing homes, pointing up the peculiarities of this setting and the absolute need of a more prudential use of antimicrobials.

Long-Term Carriage of Ciprofloxacin-Resistant Escherichia coli Isolates in High-Risk Nursing Home Residents

BACKGROUND Rates of multidrug-resistant gram-negative organisms are surpassing those of methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci in nursing homes (NHs). OBJECTIVE To characterize the incidence and duration of carriage of ciprofloxacin-resistant Escherichia coli (CipREc) in NHs and identify those in the O25b-ST131 lineage. METHODS We collected 227 CipREc isolates obtained by routine and regular surveillance of high-risk NH residents with indwelling devices. Repetitive element palindromic (REP)-polymerase chain reaction assay and multiplex polymerase chain reaction amplification for O25b-ST131 E. coli detection were performed using (GTG)5-primers and O25pabBspe and trpA2 primer pairs, respectively. RESULTS We found a high period prevalence of CipREc colonization (21.5%), high rates of recolonization with the same strain following clearing (0.46 recolonizations/ person/ year), and an acquisition incidence of 1.05 cases/1,000 person-days. Almost three-quarters of colonized residents carried strains in the O25b-ST131 E. coli lineage. Compared with isolates not in the lineage, O25b-ST131 isolates were carried significantly longer (10 vs 3 months). We identified 18 different REP-types; 2 occurred in 55% of the residents colonized with CipREc, and in more than 1 NH. Duration of CipREc carriage varied by REP-type and averaged 6 months. CONCLUSION CipREc occurred frequently in NH residents and is carried for long durations, and reacquisition following clearance is common Trial registration. ClinicalTrials.gov identifier: NCT01062841.

Enhancing Resident Safety by Preventing Healthcare-Associated Infection: A National Initiative to Reduce Catheter-Associated Urinary Tract Infections in Nursing Homes

Preventing healthcare-associated infection (HAI) is a key contributor to enhancing resident safety in nursing homes. In 2013, the U.S. Department of Health and Human Services approved a plan to enhance resident safety by reducing HAIs in nursing homes, with particular emphasis on reducing indwelling catheter use and catheter-associated urinary tract infection (CAUTI). Lessons learned from a recent multimodal Targeted Infection Prevention program in a group of nursing homes as well as a national initiative to prevent CAUTI in over 950 acute care hospitals called "On the CUSP: STOP CAUTI" will now be implemented in nearly 500 nursing homes in all 50 states through a project funded by the Agency for Healthcare Research and Quality (AHRQ). This "AHRQ Safety Program in Long-Term Care: HAIs/CAUTI" will emphasize professional development in catheter utilization, catheter care and maintenance, and antimicrobial stewardship as well as promoting patient safety culture, team building, and leadership engagement. We anticipate that an approach integrating technical and socio-adaptive principles will serve as a model for future initiatives to reduce other infections, multidrug resistant organisms, and noninfectious adverse events among nursing home residents.

Empirical Antimicrobial Prescriptions in Patients with Clostridium difficile Infection at Hospital Admission and Impact on Clinical Outcome

Objective.

To determine, among patients with Clostridium difficile infection (CDI) at hospital admission, the impact of concurrent use of systemic, non-CDI-related antimicrobials on clinical outcomes and the risk factors associated with unnecessary antimicrobial prescribing.

Design.

Retrospective cohort study.

Setting.

University-affiliated community hospital.

Methods.

We reviewed computerized medical records for all patients with CDI at hospital admission during a 24-month period (January 1, 2008, through December 31, 2009). Colectomy, discharge to hospice, and in-hospital mortality were considered to be adverse outcomes. Antimicrobial use was considered unnecessary in the absence of physical signs and laboratory or radiological findings suggestive of an infection other than CDI or in the absence of antimicrobial activity against the organism(s) recovered from clinical cultures.

Results.

Among the 94 patients with CDI at hospital admission, 62% received at least one non-CDI-related antimicrobial during their hospitalization for CDI. Severe complicated CDI (odds ratio [OR], 7.1 [95% confidence interval {CI}, 1.8–28.5]; P = .005), duration of non-CDI-related antimicrobial exposure (OR, 1.2 [95% CI, 1.03–1.36]; P = .016), and age (OR, 1.1 [95% CI, 1.0–1.1]; P = .043) were independent risk factors for adverse clinical outcomes. One-third of the patients received unnecessary antimicrobial therapy. Sepsis at hospital admission (OR, 5.3 [95% CI, 1.8–15.8]; P = .003) and clinical suspicion of urinary tract infection (OR, 9.7 [95% CI, 2.9–32.3]; P< .001) were independently associated with unnecessary antimicrobial prescriptions.

Conclusions.

Empirical use of non-CDI-related antimicrobials was common. Prolonged exposure to non-CDI-related antimicrobials was associated with adverse clinical outcomes, including increased in-hospital mortality. Minimizing non-CDI-related antimicrobial exposure in patients with CDI seems warranted.

Biofilm-based infections in long-term care facilities

The recent trend in the early admittance to long-term care facilities (LTCFs) of severely injured patients transferred from general hospitals has given a new dynamic to the incidence of healthcare-associated infections, including biofilm-based infections related to the implant of urinary and intravascular catheters, and the onset of pressure ulcers. Catheter-associated urinary tract infections lead in most of the surveys on LTCFs, approximately 80% of urinary tract infections in these settings being due to the short- or long-term insertion of a urinary catheter. Furthermore, the implantation of intravascular catheters is often responsible for catheter-related bloodstream infections caused by the development of an intraluminal biofilm. Pressure ulcers, frequently occurring in bedridden patients admitted to LTCFs, are also susceptible to infection by biofilm-growing aerobic and anaerobic bacteria, the biofilm formation on the wound being the main reason for its delayed healing.

Reducing inappropriate antibiotic prescribing in the residential care setting: current perspectives

Residential aged care facilities are increasingly identified as having a high burden of infection, resulting in subsequent antibiotic use, compounded by the complexity of patient demographics and medical care. Of particular concern is the recent emergence of multidrug-resistant organisms among this vulnerable population. Accordingly, antimicrobial stewardship (AMS) programs have started to be introduced into the residential aged care facilities setting to promote judicious antimicrobial use. However, to successfully implement AMS programs, there are unique challenges pertaining to this resource-limited setting that need to be addressed. In this review, we summarize the epidemiology of infections in this population and review studies that explore antibiotic use and prescribing patterns. Specific attention is paid to issues relating to inappropriate or suboptimal antibiotic prescribing to guide future AMS interventions.

[The challenge of infections and multiresistant bacteria among the elderly living in long-term care facilities]

Healthcare-associated infections not only affect patients in acute care hospitals but also patients in need of long-term care. As the elderly are generally most affected, the demographic change in Germany faces a range of increasing challenges in the field of infection control. The ageing process itself is accompanied by several physiological and pathological changes which may result in an increase in the risk of infectious diseases. Elderly living in long-term care facilities (LTCFs) may in addition be exposed to further risks due to their everyday life in a community, nursing care and the, to some extent, inappropriate use of antibiotics. Bacteria that have become resistant to commonly used antimicrobial agents are meanwhile prevalent in nursing homes. Caregivers often feel left alone when facing the task of achieving a balance between the need for a comfortable familiar environment and the application of infection control measures according to a resolute prevention strategy. This review aims to give an overview about the characteristics of infections among the elderly, especially with respect to long-term care.

Risk of transmission of imipenem-resistantPseudomonas aeruginosa through use of mobile bathing service

OBJECTIVES

The demand for mobile bathing service (MBS) is increasing in the Japanese society. Therefore, we assessed the risk of MBS-associated infection in MBS clients and their caregivers by examining the bacterial colonization of MBS equipment and utensils.

METHODS

Bacterial isolates collected by the stamp agar culture method were examined by disk diffusion assay for their susceptibility to the following drugs: imipenem, ciprofloxacin, amikacin, azutreonam, ceftazidim, meropenem, piperacillin, tobramycin, ofloxacin and cefoperazone. Furthermore, these isolates were subtyped bySpeI-pulsed field gel electrophoresis (SpeI-PFGE).

RESULTS

Fifty-fourP. aeruginosa isolates were recovered from different sampling sites, and of these, 26 (47.3%) were isolated from pillows. Eighteen isolates (33.3%) were imipenem (IPM) resistant. The minimum inhibitory concentrations (MICs) of 17 isolates were between 16 and 32 μg/ml, and the MIC of one isolate was greater than 32 μg/ml. TheSpeI-PFGE typing of IPM-resistant isolates revealed that 13 of the 18 isolates were closely related (F=1.0-0.87).

CONCLUSION

Our findings suggest that MBS equipment and utensils, particularly pillows, are the primary sources of bacterial contamination and transmission and that there is a risk of MBS-mediated infection among MBS clients and their caregivers.

Incidence of antibiotic-resistant Escherichia coli bacteriuria according to age and location of onset: a population-based study from Olmsted County, Minnesota

OBJECTIVE

To better understand the epidemiology of drug-resistant Escherichia coli across health care and community settings.

PATIENTS AND METHODS

We conducted a population-based cohort study of the incidence of antibiotic-resistant E coli bacteriuria among different patient groups. All urine cultures with monomicrobial growth of E coli obtained from Olmsted County, Minnesota, residents from January 1, 2005, through December 31, 2009, were identified. The initial isolate per patient per year was included. Analyses were stratified by patient age and location of infection onset (ie, nosocomial, health care associated, and community associated).

RESULTS

We evaluated 5619 E coli isolates and the associated patients. During the study period, the incidence of drug-resistant bacteriuria did not change among children but increased significantly among adults of all ages, most markedly among elderly patients older than 80 years. In elderly patients, the incidence of bacteriuria with isolates resistant to fluoroquinolones increased from 464 to 1116 per 100,000 person-years (P<.001), and the incidence of bacteriuria with isolates resistant to fluoroquinolones plus trimethoprim-sulfamethoxazole increased from 274 to 512 per 100,000 person-years (P<.05). When analyzed by location of infection onset, incidence of bacteriuria with isolates resistant to trimethoprim-sulfamethoxazole, fluoroquinolones, trimethoprim-sulfamethoxazole plus fluoroquinolones, extended-spectrum cephalosporins, and more than 3 drug classes increased significantly among community-associated but not among nosocomial or health care-associated cases.

CONCLUSION

In this population-based study, the incidence of antibiotic-resistant E coli bacteriuria nearly doubled during the 5-year study period among elderly patients and those with community-associated isolates. These patient groups should be targets of interventions to slow the emergence and spread of antibiotic-resistant E coli.

Medical device-associated infections in the long-term care setting

Indwelling medical devices are increasingly used in long-term care facilities (LTCFs). These devices place residents at a heightened risk for infection and colonization and infection with multidrug-resistant organisms. Understanding the risk and pathogenesis of infection associated with commonly used medical devices can help facilitate appropriate therapy. Programs to minimize unnecessary use of indwelling medical devices in residents and maximize staff adherence to infection control and maintenance procedures are essential features of a LTCF infection prevention program. LTCFs that provide care for large numbers of residents with indwelling medical devices should routinely perform surveillance for device-related infections and develop systems for assessing the safety and efficacy of newly introduced device-related technology.

Three-year prevalence of healthcare-associated infections in Dutch nursing homes

From November 2007 for a period of three years (2007-2009), we conducted an annual one-day prevalence study of healthcare-associated infections (HAIs) among nursing home residents in the Nijmegen region of The Netherlands. In the absence of national HAI definitions applicable to the nursing home setting, we used modified definitions based on US Centers for Disease Control and Prevention criteria for bloodstream infection, lower respiratory tract infection, bacterial conjunctivitis, and gastroenteritis. For the surveillance of urinary tract infection (UTI), criteria established by the Dutch Association of Elderly Care Physicians were used. Resident characteristics were recorded and data collection was performed by the attending elderly care physicians. For the three-year period, 1275, 1323, and 1772 nursing home residents were included, resulting in a prevalence of HAIs of 6.7%, 7.6% and 7.6%, in 2007, 2008 and 2009, respectively. The demographics with respect to age (mean 81 years) and sex (31% men, 69% women) were almost identical in all three years. UTI was the most prevalent HAI with 3.5%, 4.2%, and 4.1% respectively. Most HAIs occurred among residents of rehabilitation units. The prevalence of HAIs varied by nursing home (range: 0.0-32.4%). We present the results of the first prevalence study of HAIs in Dutch nursing homes. Point prevalence studies of HAIs, as part of a quality improvement cycle, are an important cornerstone of infection control programmes in nursing homes, allowing us to further increase patient safety efforts in this setting.

Conceptual model for reducing infections and antimicrobial resistance in skilled nursing facilities: focusing on residents with indwelling devices

Infections in skilled nursing facilities (SNFs) are common and result in frequent hospital transfers, functional decline, and death. Colonization with multidrug-resistant organisms (MDROs) - including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and multidrug-resistant gram-negative bacilli (R-GNB) - is also increasingly prevalent in SNFs. Antimicrobial resistance among common bacteria can adversely affect clinical outcomes and increase health care costs. Recognizing a need for action, legislators, policy-makers, and consumer groups are advocating for surveillance cultures to identify asymptomatic patients with MDROs, particularly MRSA in hospitals and SNFs. Implementing this policy for all SNF residents may be costly, impractical, and ineffective. Such a policy may result in a large increase in the number of SNF residents placed in isolation precautions with the potential for reduced attention by health care workers, isolation, and functional decline. Detection of colonization and subsequent attempts to eradicate selected MDROs can also lead to more strains with drug resistance. We propose an alternative strategy that uses a focused multicomponent bundle approach that targets residents at a higher risk of colonization and infection with MDROs, specifically those who have an indwelling device. If this strategy is effective, similar strategies can be studied and implemented for other high-risk groups.

Health-care-associated bloodstream infections at admission to the ICU

BACKGROUND

Infections occurring among outpatients having recent contact with the health-care system have been recently classified as health-care-associated infections to distinguish them from hospital- and community-acquired infections. Patients with bloodstream infections (BSIs) were studied to assess health-care-associated infections at admission in the ICU.

METHODS

This work was a multicenter, prospective, observational study of all adult patients with BSI at ICU admission at 27 Spanish hospitals and one Argentine hospital. Cases of BSI were classified as community-acquired BSI (CAB), health-care-associated BSI (HCAB), or hospital-acquired BSI (HAB), and their characteristics were compared.

RESULTS

Of 726 BSIs, 343 (47.2%) were CABs, 252 (34.7%) were HABs, and 131 (18.0%) were HCABs. Potentially antibiotic-resistant pathogens were more frequently isolated in HABs (34.8%) and HCABs (27.6%) than in CABs (10.3%) (P < .001). Logistic regression analysis revealed that HABs (OR, 4.6; 95% CI, 2.9-7.3), HCABs (OR, 3.1; 95% CI, 1.8-5.4), and BSIs of unknown origin (OR, 1.7; 95% CI, 1.0-2.8) were independently associated with the isolation of potentially antibiotic-resistant pathogens. The incidence of inappropriate treatment was significantly higher in HABs (OR, 3.4; 95% CI, 2.1-5.3) and in HCABs (OR, 1.8; 95% CI, 1.0-3.2) than in CABs.

CONCLUSIONS

One in five BSIs diagnosed at ICU admission is health-care-associated. The incidence of potentially drug-resistant pathogens in HCABs is more similar to that of HABs, and they should be treated as such until culture data are available.

Knowledge of evidence-based urinary catheter care practice recommendations among healthcare workers in nursing homes

OBJECTIVES

To assess the knowledge of recommended urinary catheter care practices among nursing home (NH) healthcare workers (HCWs) in southeast Michigan.

DESIGN

Self-administered survey.

SETTING

Seven NHs in southeast Michigan.

PARTICIPANTS

HCWs.

MEASUREMENTS

The survey included questions about respondent characteristics and knowledge about indications, care, and personal hygiene pertaining to urinary catheters. The association between knowledge measures and occupation (nurses vs aides) was assessed using generalized estimating equations.

RESULTS

Three hundred fifty-six of 440 HCWs (81%) responded. More than 90% of HCWs were aware of measures such as cleaning around the catheter daily, glove use, and hand hygiene with catheter manipulation. They were less aware of research-proven recommendations of not disconnecting the catheter from its bag (59% nurses, 30% aides, P<.001), not routinely irrigating the catheter (48% nurses, 8% aides, P<.001), and hand hygiene after casual contact (60% nurses, 69% aides, P=.07). HCWs were also unaware of recommendations regarding alcohol-based hand rub (27% nurses and 32% aides with correct responses, P=.38). HCWs reported informal (e.g., nurse supervisors) and formal (in-services) sources of knowledge about catheter care.

CONCLUSION

Significant discrepancies remain between research-proven recommendations pertaining to urinary catheter care and HCWs' knowledge. Nurses and aides differ in their knowledge of recommendations against harmful practices, such as disconnecting the catheter from the bag and routinely irrigating catheters. Further research should focus on strategies to enhance dissemination of proven infection control practices in NHs.

Anti-adhesive coating and clearance of device associated uropathogenic Escherichia coli cystitis

PURPOSE

A previous study showed decreased uropathogen adherence using a novel anti-fouling coating consisting of mussel adhesive protein mimics conjugated to poly(ethylene glycol). We assessed the ability of methoxy polyethylene glycol-dihydroxyphenylalanine (Nerites Corp. Ltd., Madison, Wisconsin) coated ureteral stents to resist bacterial adherence, infection development and encrustation in a rabbit model of uropathogenic Escherichia coli cystitis.

MATERIALS AND METHODS

Sof-Flex stent curls that were uncoated and coated with 3 coatings, including Surphys 002, 008 and 009, respectively, and uncoated Percuflex Plus stents were inserted transurethrally into the bladder of 50 male New Zealand White rabbits (Charles River Laboratories, Montreal, Quebec, Canada), followed by instillation of uropathogenic E. coli strain GR12 (10(7) cfu). Urine was examined for bacteria on days 0, 1, 3 and 7, and for cytokine levels on day 7. On day 7 the animals were sacrificed. Stent curls and bladders were harvested for analysis. In a parallel experiment stents were challenged in vitro for 7 days with GR12 in human urine.

RESULTS

Surphys 009 coated devices showed decreased urine and stent bacterial counts compared to those in controls. Eight of 10 rabbits in the Surphys 009 group had sterile urine by day 3 vs 1 in each control group (p = 0.013), while stent adherent organisms were decreased by more than 75%. While no statistical differences were found in encrustation and bladder inflammation across the groups, immune scoring was lowest in the uncoated Sof-Flex control and Surphys 009 groups (p = 0.030).

CONCLUSIONS

Surphys 009 strongly resisted bacterial attachment, resulting in improved infection clearance over that of uncoated devices. However, this did not translate to decreased encrustation, which appeared to be independent of infection in this model.

Current treatment of pseudomonal infections in the elderly

Pseudomonas aeruginosa infections have emerged as a major infectious disease threat in recent decades as a result of the significant mortality of pseudomonal pneumonia and bacteraemia, and the evolving resistance exhibited by the pathogen to numerous antibacterials. Pseudomonas possesses a large genome; thus, the pathogen is environmentally adaptable, metabolically flexible, able to overcome antibacterial pressure by selecting for resistant strains and even able to accumulate resistance mechanisms, leading to multidrug resistance (MDR), an increasingly recognized therapeutic challenge. In fact, most research currently does not focus on maximizing the efficacy of available antibacterials; rather, it focuses on maximizing their ecological safety. The elderly population may be particularly prone to pseudomonal infection as a result of increased co-morbidities (such as diabetes mellitus and structural lung disease), the presence of invasive devices such as urinary catheters and feeding tubes, polypharmacy that includes antibacterials, and immune compromise related to age. However, age per se, as well as residence in nursing homes, may not predispose individuals to an increased risk for pseudomonal infection. On the other hand, age has been repeatedly outlined as a risk factor for MDR pseudomonal infections. The severity of pseudomonal infections necessitates prompt administration of appropriate antibacterials upon suspicion. Progress has been made in recognizing risk factors for P. aeruginosa infections both in hospitalized and community-residing patients. Antimicrobial therapy may be instituted as a combination or monotherapy: the debate cannot be definitively resolved since the available data are extracted from studies with varying targeted populations and varying definitions of response, adequacy and MDR. Empirical combination therapy maximizes the chances of bacterial coverage and exerts a lower resistance selection pressure. Although associated with increased percentages of adverse events, mainly as a result of the included aminoglycosides, empirical combination therapy seems a reasonable choice. Upon confirmation of Pseudomonas as the causative agent and awareness of its susceptibility profile, monotherapy is advocated by many, but not all, experts. Infections involving MDR strains can be treated with colistin, which has adequate efficacy and few renal adverse events, or doripenem. In the elderly, in addition to making dose modifications that are needed because of loss of renal function, the prescriber should be more cautious about the use of aminoglycoside-containing regimens, possibly replacing them with a combination of quinolone and a beta-lactam, notwithstanding the possible increased pressure for selection of resistance with the latter combination.

Incidence of antibiotic-resistant infection in long-term residents of skilled nursing facilities

BACKGROUND

Information regarding the incidence of antibiotic-resistant infection in residents of skilled nursing facilities is lacking.

METHODS

The incidence and predictors of antibiotic-resistant infection were investigated in 56,182 long-term residents of 3314 skilled nursing facilities in California, Florida, Michigan, New York, and Texas.

RESULTS

The annual incidence was 12.7 cases per 1000 long-term residents overall, which varied by state (highest incidence, New York) and type of admitting facility (highest incidence, rehabilitation hospital). The incidence was greater in younger residents, males, and residents with paraplegia, quadriplegia, peripheral vascular disease, or diabetes mellitus. Dialysis, urinary catheterization, feeding tubes, tracheostomy, and use of intravenous medications were associated with elevated risk. Adjusted odds ratios (ORs) were greatest in residents with paraplegia (OR = 2.86; 95% confidence interval [CI] = 1.67 to 4.89) and those receiving dialysis (OR = 2.84; 95% CI = 1.84 to 4.37).

CONCLUSION

There is significant variation in the risk of antibiotic-resistant infection by admitting diagnosis, device use, and facility characteristics.

Indwelling device use and antibiotic resistance in nursing homes: identifying a high-risk group

OBJECTIVES

To quantify the relationship between indwelling devices (urinary catheters, feeding tubes, and peripherally inserted central catheters) and carriage of antimicrobial-resistant pathogens in nursing home residents.

DESIGN

Cross-sectional.

SETTING

Community nursing home in Southeast Michigan.

PARTICIPANTS

Residents with indwelling devices (n=100) and randomly selected control residents (n=100) in 14 nursing homes.

MEASUREMENTS

Data on age, functional status, and Charlson comorbidity score were collected. Samples were obtained from nares, oropharynx, groin, wounds, perianal area, and enteral feeding tube site. Standard microbiological methods were used to identify methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and ceftazidime-resistant (CTZ-R) gram-negative bacteria (GNB).

RESULTS

Use of indwelling devices was associated with colonization with MRSA at any site (odds ratio (OR)=2.0, P=.04), groin (OR=4.8, P=.006), and perianal area (OR=3.6, P=.01) and CTZ-R GNB at any site (OR=5.6, P=.003). Use of enteral feeding tubes was associated with MRSA colonization in the oropharynx (OR=3.3, P=.02).

CONCLUSION

Use of indwelling devices is associated with greater colonization with antimicrobial-resistant pathogens. This study serves as an initial step in defining a high-risk group that merits intensive infection control efforts.

Infection control in pediatric extended care facilities

Pediatric extended care facilities provide for the biopsychosocial needs of patients younger than 21 years of age who have sustained self-care deficits. These facilities include long-term and residential care facilities, chronic disease and specialty hospitals, and residential schools. Infection control policies and procedures developed for adult long-term care facilities, primarily nursing homes for elderly people, are not applicable to long-term care facilities that serve pediatric patients. This article reviews the characteristics of pediatric extended care facilities and their residents, and the epidemic and endemic nosocomial infections, infection control programs, and antimicrobial resistance profiles found in pediatric extended care facilities.

Extended-spectrum beta-lactamases: a clinical update

Extended-spectrum beta-lactamases (ESBLs) are a rapidly evolving group of beta-lactamases which share the ability to hydrolyze third-generation cephalosporins and aztreonam yet are inhibited by clavulanic acid. Typically, they derive from genes for TEM-1, TEM-2, or SHV-1 by mutations that alter the amino acid configuration around the active site of these beta-lactamases. This extends the spectrum of beta-lactam antibiotics susceptible to hydrolysis by these enzymes. An increasing number of ESBLs not of TEM or SHV lineage have recently been described. The presence of ESBLs carries tremendous clinical significance. The ESBLs are frequently plasmid encoded. Plasmids responsible for ESBL production frequently carry genes encoding resistance to other drug classes (for example, aminoglycosides). Therefore, antibiotic options in the treatment of ESBL-producing organisms are extremely limited. Carbapenems are the treatment of choice for serious infections due to ESBL-producing organisms, yet carbapenem-resistant isolates have recently been reported. ESBL-producing organisms may appear susceptible to some extended-spectrum cephalosporins. However, treatment with such antibiotics has been associated with high failure rates. There is substantial debate as to the optimal method to prevent this occurrence. It has been proposed that cephalosporin breakpoints for the Enterobacteriaceae should be altered so that the need for ESBL detection would be obviated. At present, however, organizations such as the Clinical and Laboratory Standards Institute (formerly the National Committee for Clinical Laboratory Standards) provide guidelines for the detection of ESBLs in klebsiellae and Escherichia coli. In common to all ESBL detection methods is the general principle that the activity of extended-spectrum cephalosporins against ESBL-producing organisms will be enhanced by the presence of clavulanic acid. ESBLs represent an impressive example of the ability of gram-negative bacteria to develop new antibiotic resistance mechanisms in the face of the introduction of new antimicrobial agents.

Prolonged outbreak of infection due to TEM-21-producing strains of Pseudomonas aeruginosa and enterobacteria in a nursing home

Over a 6-year period, 24 extended-spectrum beta-lactamase (ESBL)-producing isolates of Pseudomonas aeruginosa were collected from 18 patients living in a nursing home. These isolates had a delayed development of a red pigment and exhibited a similar antibiotype (resistance to all beta-lactams except for imipenem and to gentamicin, tobramycin, netilmicin, ciprofloxacin, and rifampin) associated with the production of the TEM-21 beta-lactamase and a type II 3'-N-aminoglycoside acetyltransferase [AAC(3)-II] enzyme. Surprisingly, serotyping showed that these isolates belonged to four successive serotypes (P2, P16, P1, and PME), although molecular typing by PCR methods and pulsed-field gel electrophoresis yielded identical or similar profiles. Moreover, in all isolates the bla(TEM-21) gene was part of a chromosomally located Tn801 transposon truncated by an IS6100 element inserted within the resolvase gene, and the aac(3)-II gene was adjacent to this structure. During the same period, 17 ESBL-producing isolates of enterobacteria were also collected from 10 of these patients. These isolates harbored a similar large plasmid that contained the bla(TEM-21) and the aac(3)-II genes and that conferred additional resistance to sulfonamides and chloramphenicol, as well as to kanamycin, tobramycin, netilmicin, and amikacin, conveyed by an AAC(6')-I enzyme. The bla(TEM-21) gene was part of the Tn801 transposon disrupted by IS4321. Thus, a single clone of P. aeruginosa that had undergone a progressive genetic drift associated with a change in serotype appeared to be responsible for an outbreak of nosocomial infections in a nursing home. This strain has probably acquired the bla(TEM-21)-encoding plasmid that was epidemic among the enterobacteria at the institution, followed by chromosomal integration and genomic reorganization.

Longitudinal trends in antimicrobial susceptibilities across long-term-care facilities: emergence of fluoroquinolone resistance

BACKGROUND

Antibiotic resistance in the longterm-care facility (LTCF) setting is of increasing concern due to both the increased morbidity and mortality related to infections in this debilitated population and the potential for transfer of resistant organisms to other healthcare settings. Longitudinal trends in antibiotic resistance in LTCFs have not been well described.

DESIGN

Correlational longitudinal survey study.

SETTING

Four LTCFs in Pennsylvania.

SUBJECTS

All clinical cultures of residents of the participating LTCFs (700 total beds) from 1998 through 2003. We assessed the annual prevalence of resistance to various antimicrobials of interest for the following organisms: Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus, and enterococcus species.

RESULTS

A total of 4,954 clinical isolates were obtained during the study. A high prevalence of antimicrobial resistance was noted for many organism-drug combinations. This was especially true for fluoroquinolone susceptibility among the Enterobacteriaceae (susceptibility range, 51.3% to 92.2%). In addition, the prevalence of resistance to various agents differed significantly across study sites. Finally, significant increasing trends in resistance were noted over time and were most pronounced for fluoroquinolone susceptibility among the Enterobacteriaceae.

CONCLUSIONS

The prevalence of antimicrobial resistance has increased significantly in LTCFs, although trends have varied substantially across different institutions. These trends have been particularly pronounced for fluoroquinolone resistance among the Enterobacteriaceae. These findings demonstrate that antimicrobial resistance is widespread and increasing in LTCFs, highlighting the need for future studies to more clearly elucidate the risk factors for, and potential interventions against, emerging resistance in these settings.

Prevalence and risk factors of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in an Israeli long-term care facility

The purpose of this study was to ascertain the prevalence of extended-spectrum beta-lactamases (ESBLs) among Escherichia coli and Klebsiella pneumoniae strains obtained from urine samples of residents of a long-term care facility and to determine the risk factors for acquisition of ESBL-producing strains. All urine samples collected from January 2003 to October 2003 that were positive for E. coli or K. pneumoniae were tested for the presence of ESBL. Records of patients with ESBL-positive (ESBL-P) samples were analyzed for clinical and demographic data. The records of a matched control group of patients whose urine samples were positive for E. coli or K. pneumoniae but were ESBL-negative (ESBL-N) were also analyzed. The overall rate of ESBLs among the E. coli and K. pneumoniae samples was 25.6%. Of 350 urine samples that grew E. coli, 77 (22%) were positive for ESBL; 34 of 84 (40.5%) samples that grew K. pneumoniae were ESBL-P. Male sex, treatment in the subacute care unit, recent antimicrobial treatment, pressure sores, (percutaneous endoscopic gastrostomy) PEG tube, anemia, hypoalbuminemia, permanent urinary catheter, and any recent invasive procedure were all associated with ESBL-P bacteria in the univariate analysis. The multivariate analysis revealed three independent risk factors for the presence of an ESBL-producing strain: anemia, permanent urinary catheter, and previous antibiotic use. Fluoroquinolones were most strongly associated with the development of ESBL-producing bacteria. The prevalence of ESBL-producing E. coli and K. pneumoniae in the long-term care facility investigated was unexpectedly high and corroborates the notion that long-term care facilities could be important reservoirs of resistant bacteria. Identification of the risk factors for ESBLs is the first step in formulating an effective strategy to curtail the spread of ESBL resistance in long-term care facilities.

Antimicrobial susceptibilities of urinary pathogens in a multidisciplinary long-term care facility

In order to determine bacterial distribution and antimicrobial susceptibility of urinary pathogens in a long-term-care-facility (LTCF), urine cultures were examined when clinically indicated. The LTCF consists of 286 beds, housing 931 residents during 32 months, in various wings; independent and frail residents (wing-A), nursing and demented patients (wing-B), and skilled-nursing patients (wing-C). A total of 1,401 positive urine cultures were obtained: E. coli was isolated significantly less often in wing-C than in wing-A (p = 0.02) and wing-B (p = 0.009). There was no significant difference in frequency of other organisms. Susceptibility of organisms decreased significantly from wing-C to wing-B (p < 0.05-0.001), and from wing-B to wing-A (p < 0.05-0.001). Susceptibility rates' decreased significantly over time in wing-B, less in wing-C and not at all in wing-A.

IN CONCLUSION

When selecting empiric antibiotic therapy for serious urinary tract infection in a long-term-care resident, one should take into account the microbial environment of the individual patient's department.

Risk factors for antibiotic-resistant infection and treatment outcomes among hospitalized patients transferred from long-term care facilities: does antimicrobial choice make a difference?

A prospective observational study of 153 patients transferred from long-term care facilities and admitted to acute-care hospitals who had microbiologically confirmed infections was undertaken to determine the risk factors, outcomes, and resource use associated with isolation of antibiotic-resistant bacteria (ARB). Eighty patients (52%) were infected with ARB. In multivariable logistic analysis, the presence of a feeding tube (odds ratio, 3.0) or polymicrobial infection (odds ratio, 4.6) was associated with isolation of ARB. Forty-nine percent of patients infected with ARB received an initial antibiotic regimen to which their isolate was not susceptible. Fifty-one percent of all patients had a change in their antibiotic regimen during their hospital course. For these patients, length of stay, number of days of antibiotic therapy, and cost of hospitalization were significantly higher. However, neither infection with ARB nor appropriateness of initial treatment regimen was significantly related to outcome or resource use.

The etiology of urinary tract infection: traditional and emerging pathogens

The microbial etiology of urinary infections has been regarded as well established and reasonably consistent. Escherichia coli remains the predominant uropathogen (80%) isolated in acute community-acquired uncomplicated infections, followed by Staphylococcus saprophyticus (10% to 15%). Klebsiella, Enterobacter, and Proteus species, and enterococci infrequently cause uncomplicated cystitis and pyelonephritis. The pathogens traditionally associated with UTI are changing many of their features, particularly because of antimicrobial resistance. The etiology of UTI is also affected by underlying host factors that complicate UTI, such as age, diabetes, spinal cord injury, or catheterization. Consequently, complicated UTI has a more diverse etiology than uncomplicated UTI, and organisms that rarely cause disease in healthy patients can cause significant disease in hosts with anatomic, metabolic, or immunologic underlying disease. The majority of community-acquired symptomatic UTIs in elderly women are caused by E coli. However, gram-positive organisms are common, and polymicrobial infections account for up to 1 in 3 infections in the elderly. In comparison, the most common organisms isolated in children with uncomplicated UTI are Enterobacteriaceae. Etiologic pathogens associated with UTI among patients with diabetes include Klebsiella spp., Group B streptococci, and Enterococcus spp., as well as E coli. Patients with spinal cord injuries commonly have E coli infections. Other common uropathogens include Pseudomonas and Proteus mirabilis.Recent advances in molecular biology may facilitate the identification of new etiologic agents for UTI. The need for accurate and updated population surveillance data is apparent, particularly in light of concerns regarding antimicrobial resistance. This information will directly affect selection of empiric therapy for UTI.

Trends in antibiotic use and cost and influence of case-mix and infection rate on antibiotic-prescribing in a long-term care facility

BACKGROUND

Antibiotic use and cost indicators have been developed specifically for the long-term care facility (LTCF) setting. Approximately 50% of the variation in these indicators was explained by the variation in infection rate. The objectives of this study were to further assess the utility of the antibiotic use and cost indicators in a different LTCF and to determine the correlation of case-mix and these indicators.

METHODS

Antibiotic use and cost indicators were collected monthly by unit (N = 10) and by physician (N = 6) at a 433-bed LTCF in Syracuse, New York, from February 1999 to September 2001. Indicators included incidence (number of antibiotic courses per 1000 resident care-days) of antibiotic use, antibiotic utilization ratio ([AUR]; ratio of the number of antibiotic-days to the number of resident care-days), cost per antibiotic-day, and cost per resident care-day. Case-mix variation was measured with the case-mix index (CMI) of the Resource Utilization Group II system. Simple linear and multilinear regression analyses were used to evaluate correlations of continuous variables.

RESULTS

Among the 10 units or 6 physicians, there was a significant difference in the average values for all indicators. Correlation between unit- or physician-specific CMI and antibiotic use or cost indicators or infection rate was poor. However, there was a significant positive correlation between unit- or physician-specific infection rate and incidence of antibiotic use, AUR, and cost per resident care-day but not cost per antibiotic-day. With use of multilinear regression analysis to control for CMI and cost per antibiotic-day, infection rate was a significant predictor of incidence of antibiotic use (R2 = 0.65; P <.001) and AUR (R2 = 0.78; P <.001).

CONCLUSIONS

This study provides further evidence that the antibiotic use and cost indicators developed specifically for LTCFs can detect significant variation among units within a facility and among physicians. However, there was no correlation between CMI and antibiotic use or cost indicators. After controlling for case-mix variation and cost per antibiotic-day, variation in infection rate explained most of the variation in incidence of antibiotic use and AUR.

Epidemiology of bloodstream infection in nursing home residents: evaluation in a large cohort from multiple homes

This study sought to reevaluate the epidemiology of bloodstream infection in nursing home residents. The records of 166 nursing home residents admitted to an urban, public, university-affiliated hospital with 169 episodes of bloodstream infection between January 1997 and April 2000 were retrospectively reviewed. The most common organisms isolated were Escherichia coli (27% of isolates), Staphylococcus aureus (18%; 29% were methicillin-resistant strains), and Proteus mirabilis (13%). There was minimal resistance to quinolones and third-generation cephalosporins among aerobic gram-negative bacilli. The most common sources were the urinary tract (51% of episodes) and the lungs (11%); a source was not identified in 22% of episodes. Hospital mortality was 18%. Independent predictors of hospital mortality were a pulmonary source of infection, systolic blood pressure <90 mm Hg, and leukocytosis >20,000 cells/mm3. Compared with other studies published in the past 2 decades, mortality was lower. The most common resistant organism was methicillin-resistant S. aureus.

The etiology of urinary tract infection: traditional and emerging pathogens

The microbial etiology of urinary infections has been regarded as well established and reasonably consistent. Escherichia coli remains the predominant uropathogen (80%) isolated in acute community-acquired uncomplicated infections, followed by Staphylococcus saprophyticus (10% to 15%). Klebsiella, Enterobacter, and Proteus species, and enterococci infrequently cause uncomplicated cystitis and pyelonephritis. The pathogens traditionally associated with UTI are changing many of their features, particularly because of antimicrobial resistance. The etiology of UTI is also affected by underlying host factors that complicate UTI, such as age, diabetes, spinal cord injury, or catheterization. Consequently, complicated UTI has a more diverse etiology than uncomplicated UTI, and organisms that rarely cause disease in healthy patients can cause significant disease in hosts with anatomic, metabolic, or immunologic underlying disease. The majority of community-acquired symptomatic UTIs in elderly women are caused by E coli. However, gram-positive organisms are common, and polymicrobial infections account for up to 1 in 3 infections in the elderly. In comparison, the most common organisms isolated in children with uncomplicated UTI are Enterobacteriaceae. Etiologic pathogens associated with UTI among patients with diabetes include Klebsiella spp., Group B streptococci, and Enterococcus spp., as well as E coli. Patients with spinal cord injuries commonly have E coli infections. Other common uropathogens include Pseudomonas and Proteus mirabilis.Recent advances in molecular biology may facilitate the identification of new etiologic agents for UTI. The need for accurate and updated population surveillance data is apparent, particularly in light of concerns regarding antimicrobial resistance. This information will directly affect selection of empiric therapy for UTI.

Urinary tract infection at the age extremes: pediatrics and geriatrics

Urinary tract infections (UTIs) are common and generally benign conditions among healthy, sexually active young women without long-term medical sequelae. In contrast, UTIs are more complicated among those individuals at either end of the age spectrum: infants/young children and geriatrics. UTI in children younger than 2 years has been associated with significant morbidity and long-term medical consequences, necessitating an extensive and somewhat invasive imaging evaluation to identify possible underlying functional or anatomic abnormalities. Pediatric UTI should be considered complicated until proved otherwise, and treatment should reflect the severity of signs and symptoms. Management in the acutely ill child frequently involves parenteral broad-spectrum antimicrobial agents, and less ill children can be treated with trimethoprim- sulfamethoxazole (TMP-SMX), beta-lactams, and cephalosporins.UTI among older patients (>65 years) may be complicated by comorbidities, the baseline presence of asymptomatic bacteriuria, and benign urinary symptoms that can complicate diagnosis. The etiology of UTI encompasses a broader spectrum of infecting organisms than is seen among younger patients and includes more gram-positive organisms. Symptomatic UTI is generally more difficult to treat than among younger populations. Management should be conservative, of longer treatment durations, and cover a broad spectrum of possible uropathogens. Oral or parenteral treatment with a fluoroquinolone for 7 days is the preferred empiric approach. TMP-SMX can also be considered a first-line agent in women only, but only if the pathogen is known to be TMP-SMX sensitive.

Resistant pathogens in urinary tract infections

Antimicrobial susceptibility of bacteria causing urinary tract infection (UTI) has evolved over several decades as antimicrobial exposure has repeatedly been followed by emergence of resistance. Older populations in the community, long-term care facilities, or acute care facilities have an increased prevalence of resistant bacteria isolated from UTI. Resistant isolates are more frequent in long-term care populations than the community. Resistant isolates include common uropathogens, such as Escherichia coli or Proteus mirabilis, and organisms with higher levels of intrinsic resistance, such as Pseudomonas aeruginosa or Providencia stuartii. Isolation of resistant organisms is consistently associated with prior antimicrobial exposure and higher functional impairment. The increased likelihood of resistant bacteria makes it essential that a urine specimen for culture and susceptibility testing be obtained before instituting antimicrobial therapy. Therapy for the individual patient must be balanced with the possibility that antimicrobial use will promote further resistance. Antimicrobial therapy should be avoided unless there is a clear clinical indication. In particular, asymptomatic bacteriuria should not be treated with antimicrobials. Where symptoms are mild or equivocal, urine culture results should be obtained before initiating therapy. This permits selection of specific therapy for the infecting organism and avoids empiric, usually broad-spectrum, therapy. Where empirical therapy is necessary, prior infecting organisms should be isolated, and recent antimicrobial therapy, as well as regional or facility susceptibility patterns, should be considered in antimicrobial choice. Where empirical therapy is used, it should be reassessed 48 to 72 hours after initiation, once pretherapy cultures are available.