Henry G. Spratt, Jr, PhD, is the senior microbiologist and professor in the Department of Biology, Geology, and Environmental Science at the University of Tennessee at Chattanooga. His microbial ecologically based research, which now focuses on the presence of viable pathogens in clinic environments, has resulted in over 110 presentations at conferences and over 25 publications.

Henry G. Spratt, Jr, PhD

Sick baby sleeping in NICU bed with oxygen monitor and head bandages

(Adobe Stock 580421099 by Leslie Rodriguez)

Every woman who becomes pregnant should be aware that her personal health decisions will play a critical role in the health of her fetus. In fact, the first 1000 days of a child’s life (from conception to the child’s second birthday) are thought to be the time required to ensure that the child will be healthy and develop properly. During those 1000 days, the mother’s diet will be important and affect fetal health.

However, nutritional health for a newly pregnant mother is not the only thing that she should be concerned about. There are lifestyle choices she must make even before she becomes pregnant to help provide a developing embryo and fetus with the best chances at a safe pregnancy. When mothers do not follow basic rules regarding their lifestyles, their newborns may have a low weight at birth. These neonates with low birth weight are 5 times more likely to die than neonates of mothers who follow prenatal guidelines.

Table 1. List of Measures a Pregnant Woman Can Follow to Help Ensure the Birth of a Healthy Neonate

For many pregnant mothers, information to help them provide the best conditions for their developing fetus may come from a basic self-help list. One such list from the Eunice Kennedy Shriver National Institute of Child Health and Human Development in the National Institutes of Health provides guidelines that include 11 items she should follow for a healthy pregnancy (

 Many of these self-help lists focus on fetal prenatal care from the perspective of the mother’s lifestyle. Items she must consider include things to do and things not to do related to diet, exercise, alcohol consumption, and smoking. 

For example, the mean gestational age at birth of neonates of women who smoked and drank heavily was found to be significantly lower than that of neonates of women who did not smoke or drink during pregnancy (267 vs 274 days; 

 A pregnant mother should consider developing a plan for regular prenatal care from an experienced health care provider. These caregivers can include obstetricians, family practice physicians, or a certified nurse-midwife or certified professional midwife.

 If a newly pregnant woman follows these guidelines, is that all she should be concerned about?

As noted in Table 1, the last entry points show the need for a pregnant woman to be careful not to become infected by a pathogen while carrying her fetus. A pregnant woman is susceptible to infection by various pathogens. Vaginal yeast infections are relatively common during pregnancy but usually cause no complications. Other infections by pathogens can include the usual list of suspects: bacteria, viruses, fungi, and parasites. The source of these pathogens can be from other individuals, insect bites, contact with animals, airborne exposure, contaminated food or water, or sexual contact. Many such infections during pregnancy may be harmless to the developing fetus. However, some may cause premature birth, low birth weight, congenital disabilities, learning problems, and possible loss of the fetus.

 Physicians treating a pregnant woman infected by bacterial pathogens have limited choices in their response due to the impact that certain drugs (eg, antibiotics) may have on the developing fetus.

Table 2. List of Infectious That Can Cause Damage to a Fetus

Infections linked to problems during pregnancy include many pathogens such as bacteria, viruses, yeasts, and some protozoa (

). Sexually transmitted pathogens, such as those that cause chlamydia and gonorrhea, can result in conjunctivitis or pneumonia in a neonate.

 If gonorrhea is transferred to the neonate’s eyes as they pass through the birth canal, blindness can result. Numerous viral pathogens can cause serious problems for a developing fetus.

One well-known virus, the Zika virus, affects pregnancy and caused a great deal of concern in the US in 2015 and 2016 when an outbreak of the mosquito-borne virus occurred. It is estimated that 5% of pregnant women infected by the Zika virus had fetuses with brain abnormalities, with the most common being microcephaly (smaller than normal head size).

More likely, problems associated with viral infections will be caused by
cytomegalovirus (an estimated 60% of women in developed countries are infected by this virus), which can result in neonatal hearing loss. Infection by rubella virus can result in spontaneous abortion or stillbirth. HIV infection of a developing fetus is much less common than it once was, but it can still cause major problems for neonates. As of 2015, the rate of transfer of HIV from infected mothers to their fetuses decreased to less than 1%, but any fetus that contracts the virus will have HIV positivity as a neonate, and the disease can later progress to AIDS.

Infection by the influenza virus in pregnant women has been linked to an increased risk of pregnancy complications.

 Many other types of viral infection have been linked to lowered incidence of survival for neonates.

During pregnancy, bacterial urinary tract infections (UTIs) are more common than in the general population. Pregnant women with UTIs are often asymptomatic, requiring periodic screening of urine for possible positive culture results.

Generally, levels of pathogens in the urine must be higher than 105 colony-forming units for many pathogens and lower if group B Streptococcus (GBS) is observed for preventive measures to be recommended.7 The gastrointestinal and genital tracts of an estimated 18% of women worldwide have GBS colonization. If a prenatal infection due to GBS occurs, the outcome can be maternal death, stillbirth, or neonatal death.

 In fact, infection by GBS is the leading cause of life-threatening bacterial infections in neonates.

 Antibiotics are generally prescribed for a pregnant mother if any GBS is detected in her urine. However, care must be given to the type of antibiotic used (eg, penicillins and cephalosporins are generally considered safe during pregnancy, whereas tetracyclines should be avoided).

Suppose the use of antibiotics to manage bacterial infections in a pregnant woman is potentially hazardous to her developing fetus. Are there any other proactive treatments that may help reduce the impact of infection on neonates? In addition, because antibiotics do not target viral pathogens, is there anything that can be done to help reduce fetal pathologies due to viral infection in pregnant women?

The obvious answer to both questions is through vaccination. There is abundant evidence that developing fetuses receive antibodies from their mothers transplacentally (and later via breast milk) in a version of passive immunity. Thus, if bolstered through vaccination to include resistance to many common pathogens that can harm a fetus, the mother’s antibody reserves can help give the neonate a much greater chance of surviving infections. In findings from a study of the cost-effectiveness of a vaccine against GBS in pregnant women in Japan, where costs associated with the treatment of neonates infected by GBS in utero were compared with the cost of the vaccine (estimated to be $35 per dose), the use of this vaccine was found to be highly cost-effective. Additional benefits from using this vaccine may be seen through other perinatal outcomes.

 Another study about vaccine efficacy against a bacterial infection in pregnant mothers focuses on the tetanus, diphtheria, and pertussis (Tdap) vaccine (against Bordetella pertussis, which causes whooping cough). The Tdap vaccine has been found to be safe for both the mother and the developing fetus.

For viral infections in pregnant women, vaccines can also help reduce the impact of infection on fetal health. Viral vaccines against influenza and SARS-CoV-2 have been found to be safe and effective at reducing the chance of fetal infection by those viruses.

 Other vaccines for viruses such as rubella (eg, the measles, mumps, and rubella vaccine) that involve a live virus are not recommended for pregnant women. As new vaccines for viral and bacterial pathogens that pose a risk to mothers and their developing fetuses are produced, there are many agencies considering their safety. Hopefully, new vaccine regimens will become available to women who are considering becoming pregnant and provide their developing fetuses with the best possible protection against infection via passive immunity.

Overall, any woman considering pregnancy should consider all the precautions recommended in Table 1. As they develop a relationship with their caregiver, they will hopefully discuss healthy lifestyles that will include measures to help them avoid infection by pathogens that could lead to an undesirable outcome for their pregnancy.

Baker SK. 1000 days of good nutrition: in the United States or abroad, it is about equity, evidence, and leadership. 

. 2022;112(S8):S776-S778. doi:10.2105/AJPH.2022.307077

Pregnancy care. Healthline. Accessed December 21, 2023. https://www.healthline.com/health/pregnancy-care

What can I do to promote a healthy pregnancy? Eunice Kennedy Shriver National Institute of Child Health and Human Development. Accessed December 21, 2023. https://www.nichd.nih.gov/health/topics/preconceptioncare/conditioninfo/healthy-pregnancy

Odendaal HJ, Kruger M, Botha MH. Dangers of smoking cigarettes and drinking alcohol during pregnancy. 

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Prenatal care and tests. Office on Women’s Health. Accessed December 17, 2023. https://www.womenshealth.gov/pregnancy/youre-pregnant-now-what/prenatal-care-and-tests

Ledan S. Infectious diseases in pregnancy. 

. September 16, 2020. Accessed December 17, 2023. https://www.uspharmacist.com/article/infectious-diseases-in-pregnancy

Leeper C, Lutzkanin A III. Infections during pregnancy. 

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Friel LA. Infectious disease in pregnancy. Merck Manual Professional Version. Accessed December 21, 2023. https://www.merckmanuals.com/professional/gynecology-and-obstetrics/pregnancy-complicated-by-disease/infectious-disease-in-pregnancy

Silasi M, Cardenas I, Kwon JY, Racicot K, Aldo P, Mor G. Viral infections during pregnancy. 

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Mesini A, Saffioti C, Mariani M, et al. First case of 

 colonization in a preterm, extremely low-birth-weight newborn after vaginal delivery. 

Pregnancy. CDC. Accessed December 21, 2023. https://www.cdc.gov/zika/pregnancy/index.html

Seale AC, Bianchi-Jassir F, Russell NJ, et al. Estimates of the burden of group B streptococcal disease worldwide for pregnant women, stillbirths, and children. 

. 2017;65(suppl 2):S200-S219. doi:10.1093/cid/cix664

Sorano S, Procter SR, Seale AC. Cost-effectiveness analysis of maternal vaccination against group B Streptococcus in Japan. 

. 2023;14:100332. doi:10.1016/j.jvacx.2023.100332

Whooping cough vaccines are safe. CDC. Accessed December 21, 2023. https://www.cdc.gov/pertussis/pregnant/mom/safety-side-effects.html

Vaccine safety for moms-to-be. CDC. Accessed December 21, 2023. https://www.cdc.gov/vaccines/pregnancy/vacc-safety.html

Articles

The journey of pregnancy begins long before conception, with a woman's lifestyle choices profoundly influencing her future child's health. From diet to infection prevention, proactive measures are crucial.

Prevention of Prenatal Infectious Disease

Here in the United States, we’ve all noticed how hot it was this past summer. Along with the heat came disproportionate amounts of rainfall in some areas of the country. In the eastern US, many extreme rainfall events resulted in residual pools of stagnant water throughout the region—conditions ripe for the growth and spread of mosquitoes.

Climate change impact: Climate change, including rising temperatures and altered rainfall patterns, creates favorable conditions for the increased transmission of mosquito-borne diseases like West Nile Virus in the US.

West Nile virus (WNV): WNV is identified as one of the most common mosquito-borne pathogens in the US. The transmission, symptoms, and the fact that many infections are asymptomatic make early detection and prevention crucial.

Vulnerable populations: Older individuals and individuals with compromised immune systems are at a higher risk of severe WNV infections. Understanding these vulnerable populations is vital for targeted prevention efforts.

Public health measures: The importance of proactive public health measures, such as mosquito control, removing standing water, and repellents, is to reduce mosquito breeding and protect against mosquito bites.

Climate change awareness: The need for public awareness and proactive measures is to address the changing climate's impact on the spread of mosquito-borne diseases, emphasizing that being observant of local conditions is crucial in disease prevention.

Mosquitoes can be bothersome; however, these insects can also serve as vectors for disease-causing pathogens. The best-known mosquito-borne pathogen worldwide is malaria, caused by species of the protozoan 

 being the best known). Malaria is principally a tropical disease, only rarely observed in the US. Other pathogens can be spread via mosquito bites. During 2015 and 2016, mosquitoes spread another tropical pathogen, the Zika virus, into Florida and Texas.

 Infection of pregnant mothers by the Zika virus often results in fetal infections, leading to neurological defects in neonates. However, the most common mosquito-linked blood-borne disease in the US is caused by the West Nile virus (WNV). Older people, individuals with compromised immune systems, and those living in endemic regions are particularly vulnerable to this pathogen.

Figure 1  West Nile virus human neuroinvasive disease average annual incidence per 100,000 population by county of residence, 1999-2022*

@Materials developed by CDC. Reference to specific commercial products, manufacturers, companies, or trademarks does not constitute its endorsement or recommendation by the US Government, Department of Health and Human Services, or CDC.

*For 2022 preliminary data, Maryland reports state level data only; South Carolina reports state level data only for human infections.

WNV was first isolated from a Ugandan woman with fever in 1937.

 The woman recovered from the infection and 3 months later demonstrated strong neutralizing antibodies in her blood serum. The first cases of WNV in the US were observed in 1999 in New York City.

 Later studies of WNV have indicated that up to 80% of human infections are subclinical or asymptomatic.

 Frequent symptoms for the remaining 20% include headache, weakness, and sometimes gastrointestinal problems. Fewer than 1% of those infected can experience a neuroinvasive disease expressed as meningitis, encephalitis, or acute flaccid paralysis. Misdiagnosis of WNV meningitis can occur since the neuroinvasive symptoms can be indistinguishable from meningitis due to other etiologies.

The virus that causes WNV infections is an enveloped positive-stranded RNA virus in the Japanese encephalitis serocomplex (

 Of the 8 phylogenetic lineages of this virus studied, 8 are associated with human disease.

 WNV has become endemic in many places around the globe. The reproductive cycle of the virus requires avian reservoirs and the presence of a specific type of mosquito. The virus is transferred from birds to mosquitoes in the 

genus, which can then pass the pathogen to mammals.

 Thus, this pathogen's spread requires weather events (heavy rainfall that leads to standing, stagnant water that supports mosquito reproduction) and host birds present in the eastern US this past summer.

The most common route of infection by WNV is recent exposure to mosquitoes, but the disease has occasionally been transferred via blood transfusion or organ transplantation.

 Studies of the prevalence of WNV infections in the US have indicated that outbreaks exhibit seasonal patterns tied to mosquito abundance and activity, with most human cases occurring between June and October (see Figure). Exposure to dead birds can also serve as a vector for the WNV. The CDC recommends that if you find a higher-than-usual number of dead birds in your area, don’t touch them and contact your local Public Health Department.

From a clinical perspective, the World Health Organization encourages all laboratory workers to follow universal precautions when working with specimens from WNV-infected patients.

 A common route of infection by WNV for laboratory and healthcare workers is accidental “sticks” via sharps.

 As for infection preventionists in health care facilities, there is little to be done to prevent the spread of WNV in their facility other than to follow normal clinical precautions. However, due to the link to mosquitoes, infection prevention measures targeting possible breeding sites outside of health care facilities should be part of planning whenever warm, wet conditions prevail. Such mosquito prevention and control measures may include larviciding and adulticiding (insecticides that control either the larval or adult stages of mosquitoes, respectively) to reduce mosquito populations and interrupt transmission.

Personal protection measures may also be recommended to help people avoid mosquitoes while outdoors. These measures may include mosquito-repellant chemicals, such as N,N-diethyl-meta-toluamide (DEET), found in many commercially available insect repellents.

 Other chemical repellents, such as picaridin, IR 3535, or lemon-eucalyptus oil, have been found to be effective.

 Those who work outdoors may also wear clothing that covers as much skin as possible to avoid mosquito bites.

Avoiding mosquitoes may become more critical as climate change impacts temperatures and rainfall differentially around the globe. According to the Intergovernmental Panel on Climate Change, expected climatic and weather changes in North America in coming decades will include generalized warming and changes to rainfall patterns that will consist of increased heavy rainfall events, similar to weather patterns observed in the eastern US during the summer of 2023.

 All of these climate-related changes pose risks to public health by supporting mosquito reproduction, resulting in the spread of mosquito-borne pathogens like WNV.

West Nile virus human disease cases reported by month of illness onset, 1999-2022, All disease cases


@Materials developed by CDC. Reference to specific commercial products, manufacturers, companies, or trademarks does not constitute its endorsement or recommendation by the US Government, Department of Health and Human Services, or CDC.

Distribution of WNV across the US over the past few decades has been uneven, spatially and temporally. The CDC provides good summary data on US infections from 1999 to 2022. The map shows that the highest number of infections over the period occurred in the upper Midwest US.

(Figure 1) A detailed study of mosquito-borne diseases across the US for one recent year (2021) supported the idea that WNV was the most prevalent mosquito-borne disease in the US and that the pattern of infections across US States was similar to the 1999 to 2022 pattern.

 Other studies have indicated that WNV infections are most often observed during the warmer months, with a peak for the 1999 to 2022 period in August. Note that infections have persisted into the fall months, so measures targeting mosquitoes may be required in temperate areas up to at least the first frost.

Overall, even though WNV is the most commonly transmitted mosquito-borne pathogen in the US, the number of cases seen each year is relatively low. The elderly and immunocompromised individuals are most at risk. Common sense measures to remove any standing water around your home or business will help reduce mosquito breeding areas. If you find higher than usual numbers of dead birds in your area, this might indicate the local spread of WNV. You should contact your Public Health Department. Observing possible conditions that may lead to the spread of WNV will become more critical as climate change continues to bring changing weather patterns to new areas.

2023-a. Zika cases in the United States. Centers for Disease Control and Prevention. 

https://www.cdc.gov/zika/reporting/index.html#:~:text=In%202015%20and%202016%2C%20large,transmission%20in%20Florida%20and%20Texas

. Updated January 13, 2023. Accessed August 25, 2023.

Smithburn KC, Hughes TP, Burke AW, Paul JH. 1940. A neurotropic virus isolated from the blood of a native of Uganda. 

Sejvar JJ. 2003. West Nile virus: A historical overview

. 5:6-10. PMID: 21765761; PMCID: PMC3111838.

2023-c. West Nile virus. Clinical evaluation and disease. 

https://www.cdc.gov/westnile/healthcareproviders/healthCareProviders-ClinLabEval.html

. Centers for Disease Control and Prevention. Accessed September 25, 2023.

2023-b. West Nile virus. Centers for Disease Control and Prevention. 

European Center for Disease Prevention and Control (ECDPC). 2021. Factsheet about West Nile virus infection. 

https://www.ecdc.europa.eu/en/west-nile-fever/facts

Sewgobind S, F. McCracken, M. Schilling. 2023. JMM Profile: West Nile virus. 

. 72:10.1099/jmm.0.001730. doi:10.1099/jmm.0.001730.

Paz S. 2015. Climate change impacts on West Nile virus transmission in a global context. Philosophical Transactions of the Royal Society of London B Biological Science. Apr 5;370(1665). doi: 10.1098/rstb.2013.0561. PMID: 25688020; PMCID: PMC4342965.

Gibney KB, Colborn J, Baty S, Bunko AM, et al. 2012. Modifiable risk factors for West Nile virus infection during an outbreak—Arizona, 2010. 

2009. West Nile virus transmission via organ transplantation and blood transfusion - Louisiana, 2008. 

Iwamoto M, Jernigan DB, Guasch A, et al. 2003. Transmission of West Nile Virus from an organ donor to four transplant recipients. 

. 348:2196-2203. https://www.nejm.org/doi/pdf/10.1056/NEJMoa022987?articleTools=true.

2023-d. West Nile virus–Fact Sheet. Centers for Disease Control and Prevention. 

https://www.cdc.gov/westnile/resources/pdfs/wnvfactsheet_508.pdf

2017. West Nile virus – Fact Sheet. World Health Organization 

https://www.who.int/news-room/fact-sheets/detail/west-nile-virus

Tarantola A, Abiteboul D, Rachline A. 2006. Infection risks following accidental exposure to blood or body fluids in health care workers: A review of pathogens transmitted in published cases. 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115312/pdf/main.pdf

Emerson, J. 2023. Larvicides or adulticides for mosquito control, which one is the correct choice for me? 

https://mosquitoenemy.com/larvicides-or-adulticides-for-mosquito-control-which-one-is-the-correct-choice-for-me/

Brink, S. 2018. A guide to mosquito repellents, from DEET to … gin and tonic? 

https://www.npr.org/sections/goatsandsoda/2018/06/30/623865454/a-guide-to-mosquito-repellents-from-deet-to-gin-and-tonic

Intergovernmental Panel on Climate Change (IPCC). 2007 Climate change: Working Group II: Impacts, adaptation and vulnerability. Executive summary. Chapter 8: Human health. 

US Environmental Protection Agency (EPA). 2012. Climate change adaptation plan. Accessed September 30, 2023. 

http://epa.gov/climatechange/pdfs/EPA-climate-changeadaptation-plan-final-for-public-comment-2-7-13

West Nile Virus, ArboNET, Historic Data (1999-2022). Centers for Disease Control and Prevention. 

https://www.cdc.gov/westnile/statsmaps/historic-data.html

 Updated June 13, 2023. Accessed September 25, 2023.

Fagre, AC, Lyons S, Staples JE, Lindsey N. 2021. West Nile virus and other nationally notifiable arboviral diseases–United States. 

, 72:901-906. doi: http://dx.doi.org/10.15585/mmwr.mm7234a1.

The article discusses the increased risk of mosquito-borne diseases, such as West Nile Virus (WNV), in the US due to climate change. It explores the transmission, clinical aspects, and prevention measures of WNV, emphasizing the importance of public awareness and action in mitigating the impact of these diseases.

Mosquito-Borne Pathogens and Climate Change: The Case of West Nile Virus

In March of 2023, the CDC issued a warning on 

), which is spreading at an alarming rate in health care facilities and is now considered an “urgent antimicrobial resistance threat.”

 This fungal pathogen was first reported in the US in 2016, and cases have increased yearly since then. The CDC states that “The rapid rise and geographic spread of cases is concerning and emphasizes the need for continued surveillance, expanded lab capacity, quicker diagnostic tests, and adherence to proven infection prevention and control.”

 has emerged as a potential global health risk due to the bloodstream infections it can cause, resulting in high mortality rates.

 It was first identified in 2009 in Japan in the external ear canal of a patient and has been isolated in 35 other countries and on 6 continents to date.

 A recent study screening patients entering New York City health care facilities for 

 colonization in those patients, with the highest colonization rates for patients of nursing homes. Considering all of the New York City sample sites tested (ranging from hospitals to nursing homes), these researchers found that 6.9% of new patients tested were positive for 

 can affect many regions of the body and cause bloodstream and wound infections. It is most prevalent in hospital settings, thrives in warm temperatures, and is evolving due to the common usage of certain disinfectants and prophylactic antifungal medications, resulting in some isolates having multidrug resistance.

 infection include recent surgery, obesity, immunosuppression, diabetes, use of broad-spectrum antibiotics and antifungals, presence of tracheostomies, PEG tubes, and ventilators.

 Long-term usage of broad-spectrum antibiotics can also be a risk factor for acquiring 

 Recent studies illustrate that the 30-day mortality of infected patients in an ICU was 31%.

 is efficiently transmitted among hosts and typically arises from the host’s microflora.

 It can be spread via direct contact with another person and by shared equipment such as blood pressure cuffs and pulse oximeters.

 In the limited studies conducted on the survivability of 

 on surfaces, one study has suggested that this fungal pathogen can survive on plastic surfaces for up to 14 days under dry conditions.

 survived on surfaces including glass, plastic, wood, cotton fabric, and stainless steel for up to 3 weeks.

 has been found most consistently to colonize the axilla and groin, which are common locations for swabbing for screening.

 Given its transmissibility, the CDC recommends the usage of proper hand hygiene, isolation of infected patients, contact precautions for health care personnel, daily cleaning, and terminal room disinfection.

  Further, expert recommendations also include susceptibility testing, staff education, and long-term surveillance for 

 The CDC does not recommend treatment of 

 identified from noninvasive sites (eg skin colonization) if there is no evidence of infection. However, good infection control and prevention should always be used.

Precautions for COVID-19 Could Have Exacerbated the 

Precautions in health care facilities put in place during the COVID-19 pandemic, targeting airborne pathogen spread may have inadvertently shifted focus away from prevention of surface contamination; thus, the rapid expansion in infections due to 

 over the past 5 years may in part be due to somewhat reduced levels of cleaning/disinfection of surfaces in some facilities. Standard techniques encouraged by the CDC for infection prevention in health care facilities that should also apply to the reduction of 

 infections start with the practice of good hand hygiene. Hand washing with soap and warm water should be done frequently, with the liberal use of alcohol-based hand sanitizers at other times. 

 has been found to be readily killed by alcohols in these sanitizers.

 Infection prevention measures reflecting the most up-to-date information on 

, established by an infection preventionist (if present), should always be followed.

 in microbiology labs have been slow to develop. Some of the readily available diagnostic kits (eg API ID 32 C system (Biomerieux) have been found to misidentify 

 Molecular tools like real-time Polymerase chain reaction test and other more complex systems have been found to accurately identify 

, but at a steep cost for time and the instruments and reagents required.

 A relatively new culture-based selective and differential medium, CHROMagar Candida Plus has recently become available. This medium was compared with another cultural-based 

 detection system (dulcitol enrichment broth—requiring later analysis using matrix-assisted laser desorption ionization-time of flight mass spectrometry [MALDI-TOF MS]) using the same swab surveillance samples.

 Data from the CHROMagar Candida Plus system produced good results after 3 days of incubation and is being considered an excellent "presumptive” test medium for the presence of 

 has been found to survive very harsh conditions, including desiccation and high-saline environments. In addition, 

 produces biofilms which may also interfere with the efficiency of disinfectants.

 Research on the use of disinfectants and antiseptics on surfaces or sensitive tissues have pointed to some unusual findings with regard to the efficacy of fairly-well known chemical agents.

 For example, quaternary ammonium compounds (quats), well known to be highly great effective in the control of bacterial pathogens, have generated mixed results when applied to the control of 

 The use of chlorine-based disinfectants has been found to be much better in controlling 

 on surfaces. As for antiseptics used to control 

, another example of a quat showing reduced effectiveness is chlorhexidine gluconate, which is often used in soaps for body washes. Chlorhexidine gluconate soaps have shown limited efficacy in the control of 

 for infected patients bathed regularly in these soaps. Alcohols have been found to provide the best antiseptic control of 

 in clinical environments is proving to be problematic. In addition to the development of disinfectant-resistant strains of 

, inappropriate application of these chemicals can lead to new problems. Strict adherence to manufacturers’ recommendations for contact times may not always be followed. For many disinfectants, the best fungal killing occurs with contact (“wetting”) times of up to 10 minutes. If this contact timing proves difficult in your facility, then your infection preventionist should look for other disinfectants effective against fungi—and 

 in particular—that may have shorter contact times.

 infections, antifungal agents should be prescribed sparingly. As with many pathogenic bacteria developing resistance to common antibiotics, resistance to some of the most commonly used antifungal agents against 

 has been observed. Sadly, major problems exist when targeting fungal pathogens when they invade the human body. As originally discussed by Paul Ehrlich more than a century ago, the best chemotherapeutic agents are those that work like a “magic bullet,” targeting the pathogen while leaving the host cells unharmed.

 This magic bullet concept worked well when the pathogens are prokaryotic bacteria. The differences in cellular physiology between prokaryotic pathogens and host eukaryotic cells are enough to allow for the development of chemical agents that target bacterial structures and metabolism and not host cells. The issue that comes up when looking for new chemotherapeutic antifungals (eg echinocandins) to target 

 is that this pathogen has a eukaryotic structure and metabolism that is similar to that of human cells. Thus, critical limitations exist with many antifungal drugs against 

Antifungal agents that have been approved for use against 

 have included fluconazole, amphotericin B, and caspofungin. However, strains of 

 resistant to these drugs have been discovered. According to the CDC, 

 resistance to fluconazole and amphotericin B has been found in about 90% and 30% of isolates, with fewer that 5% of 

 isolates showing any resistance to caspofungin.

Of this group of agents, caspofungin is a fungicide that has been approved for internal use by the US Food and Drug Administration.

 This agent works by inhibiting enzymes crucial to synthesizing fungal cell wall components – something that human cells cannot do. However, the newly developed resistance of 

 against caspofungin appears to be due to a mutation in the FKS1 gene that plays a role in 

 strains that are resistant to antifungal agents and the rapid spread of this pathogen across continents, are there any other options to control this pathogen? Thankfully, researchers at the Los Angeles Biomedical Research Institute (Lundquist Institute) are working to develop such a vaccine ( 

https://lundquist.org/news/lundquist-institute-now-working-vaccine-urgent-fungal-threat-candida-auris

 Testing of the efficacy of this vaccine is still in the early stages, with very promising results in rodent models. The next step will be to run human trials of the vaccine. Such a vaccine may prove helpful in limiting the spread of 

 between susceptible humans. Although the use of vaccines will have little direct impact on infection prevention in health care facilities, the development of an effective vaccine may buy time that can then be used to help develop new and better types of disinfectants and cleaning/disinfecting procedures to control this pathogen on surfaces in health care facilities, as well as time to develop new types of antifungals.

1. Centers for Disease Control and Prevention (CDC). 2023. Increasing threat of spread of antimicrobial-resistant fungus in health care facilities. Accessed May 12, 2023. 

https://www.cdc.gov/media/releases/2023/p0320-cauris.html

2. Pappas PG, Lionakis MS, Arendrup MC, Ostrosky-Zeichner L, Kullberg BJ. Invasive candidiasis. 

. 2018;4:18026. Published 2018 May 11. doi:10.1038/nrdp.2018.26

3. Sikora, A., M.F. Hashmi, F. Zahra. 2023. 

. Treasure Island (FL): StatPearls Publishing; February 19, 2023. Accessed May 19, 2023. 

The recent increase in drug-resistant strains of Candida auris, causing mortality at rates as high as 60%, raises questions regarding the spread of this pathogen as a health care-associated infection, cleaning/disinfecting protocol, and treatment via antifungal drugs.



Henry G. Spratt, Jr, PhD

Articles

Prevention of Prenatal Infectious Disease

Mosquito-Borne Pathogens and Climate Change: The Case of West Nile Virus

Special Report on Candida auris: An Emerging Drug-Resistant Fungal Threat

Reducing CLABSI and CAUTI: What Is an Infection Preventionist’s Role?

Inpatient and Outpatient Clinics Must Monitor Fomites as Part of IPC Protocols

Infection Prevention Is Key in a Neonatal Intensive Care Unit