Comparative assessment of methicillin resistant Staphylococcus aureus diagnostic assays for use in resource-limited settings.

BACKGROUND: The rise of methicillin-resistant Staphylococcus aureus (MRSA) is a global health concern. Paucity of data on MRSA carriage prevalence and diagnostic methods in resource-limited settings hampers efforts to define the problem and plan an appropriate response. Additionally, high variability in cost and logistical characteristics of MRSA screening methods may impede infection control efforts. We compared the performance of locally-available chromogenic agar BD CHROMagar MRSA II and two PCR-based assays (Hain GenoQuick MRSA and Cepheid Xpert SA Complete) for the detection of asymptomatic MRSA carriage in nasal swabs. RESULTS: During 2015, we enrolled 500 patients from five hospital wards at a Ugandan regional referral hospital. We found 30% prevalence of methicillin-sensitive Staphylococcus aureus (MSSA) nasal carriage, and 5.4% MRSA nasal carriage prevalence. Compared to a composite reference standard defined as a positive test result on any one of the three assays, Hain GenoQuick MRSA demonstrated the highest sensitivity (96%) followed by direct plating on CHROMagar at (70%), with the lowest sensitivity observed with Xpert SA Complete (52%). Cepheid Xpert provided the most rapid results (< 1 h) but was the most expensive (US $45-50/test). Substantially more labor was required for the Hain GenoQuick MRSA compared to Xpert SA Complete or CHROMagar tests. CONCLUSION: MRSA nasal carriage prevalence rates were low, and high diagnostic sensitivity was achieved using Hain GenoQuick MRSA. Chromogenic media had significantly lower sensitivity, but may represent a viable local option given its lower cost compared to PCR-based assays.

Kerosene lighting contributes to household air pollution in rural Uganda.

The literature on the contribution of kerosene lighting to indoor air particulate concentrations is sparse. In rural Uganda, kitchens are almost universally located outside the main home, and kerosene is often used for lighting. In this study, we obtained longitudinal measures of particulate matter 2.5 microns or smaller in size (PM2.5 ) from living rooms and kitchens of 88 households in rural Uganda. Linear mixed-effects models with a random intercept for household were used to test the hypotheses that primary reported lighting source and kitchen location (indoor vs outdoor) are associated with PM2.5 levels. During initial testing, households reported using the following sources of lighting: open-wick kerosene (19.3%), hurricane kerosene (45.5%), battery-powered (33.0%), and solar (1.1%) lamps. During follow-up testing, these proportions changed to 29.5%, 35.2%, 18.2%, and 9.1%, respectively. Average ambient, living room, and kitchen PM2.5 levels were 20.2, 35.2, and 270.0 µg/m3 . Living rooms using open-wick kerosene lamps had the highest PM2.5 levels (55.3 µg/m3 ) compared to those using solar lighting (19.4 µg/m3 ; open wick vs solar, P=.01); 27.6% of homes using open-wick kerosene lamps met World Health Organization indoor air quality standards compared to 75.0% in homes using solar lighting.

HIV drug resistance testing by high-multiplex "wide" sequencing on the MiSeq instrument.

Limited access to HIV drug resistance testing in low- and middle-income countries impedes clinical decision-making at the individual patient level. An efficient protocol to address this issue must be established to minimize negative therapeutic outcomes for HIV-1-infected individuals in such settings. This is an observational study to ascertain the potential of newer genomic sequencing platforms, such as the Illumina MiSeq instrument, to provide accurate HIV drug resistance genotypes for hundreds of samples simultaneously. Plasma samples were collected from Canadian patients during routine drug resistance testing (n = 759) and from a Ugandan study cohort (n = 349). Amplicons spanning HIV reverse transcriptase codons 90 to 234 were sequenced with both MiSeq sequencing and conventional Sanger sequencing methods. Sequences were evaluated for nucleotide concordance between methods, using coverage and mixture parameters for quality control. Consensus sequences were also analyzed for disparities in the identification of drug resistance mutations. Sanger and MiSeq sequencing was successful for 881 samples (80%) and 892 samples (81%), respectively, with 832 samples having results from both methods. Most failures were for samples with viral loads of <3.0 log10 HIV RNA copies/ml. Overall, 99.3% nucleotide concordance between methods was observed. MiSeq sequencing achieved 97.4% sensitivity and 99.3% specificity in detecting resistance mutations identified by Sanger sequencing. Findings suggest that the Illumina MiSeq platform can yield high-quality data with a high-multiplex "wide" sequencing approach. This strategy can be used for multiple HIV subtypes, demonstrating the potential for widespread individual testing and annual population surveillance in resource-limited settings.

Periconception HIV Risk Behavior Among Men and Women Reporting HIV-Serodiscordant Partners in KwaZulu-Natal, South Africa.

HIV-infected men and women who choose to conceive risk infecting their partners. To inform safer conception programs we surveyed HIV risk behavior prior to recent pregnancy amongst South African, HIV-infected women (N = 209) and men (N = 82) recruited from antenatal and antiretroviral clinics, respectively, and reporting an uninfected or unknown-HIV-serostatus pregnancy partner. All participants knew their HIV-positive serostatus prior to the referent pregnancy. Only 11 % of women and 5 % of men had planned the pregnancy; 40 % of women and 27 % of men reported serostatus disclosure to their partner before conception. Knowledge of safer conception strategies was low. Around two-thirds reported consistent condom use, 41 % of women and 88 % of men reported antiretroviral therapy, and a third of women reported male partner circumcision prior to the referent pregnancy. Seven women (3 %) and two men (2 %) reported limiting sex without condoms to peak fertility. None reported sperm washing or manual insemination. Safer conception behaviors including HIV-serostatus disclosure, condom use, and ART at the time of conception were not associated with desired pregnancy. In light of low pregnancy planning and HIV-serostatus disclosure, interventions to improve understandings of serodiscordance and motivate mutual HIV-serostatus disclosure and pregnancy planning are necessary first steps before couples or individuals can implement specific safer conception strategies.

"If I don't use a condom I would be stressed in my heart that I've done something wrong": Routine Prevention Messages Preclude Safer Conception Counseling for HIV-Infected Men and Women in South Africa.

Intended conception likely contributes to a significant proportion of new HIV infections in South Africa. Safer conception strategies require healthcare provider-client communication about fertility intentions, periconception risks, and options to modify those risks. We conducted in-depth interviews with 35 HIV-infected men and women accessing care in South Africa to explore barriers and promoters to patient-provider communication around fertility desires and intentions. Few participants had discussed personal fertility goals with providers. Discussions about pregnancy focused on maternal and child health, not sexual HIV transmission; no participants had received tailored safer conception advice. Although participants welcomed safer conception counseling, barriers to client-initiated discussions included narrowly focused prevention messages and perceptions that periconception transmission risk is not modifiable. Supporting providers to assess clients' fertility intentions and offer appropriate advice, and public health campaigns that address sexual HIV transmission in the context of conception may improve awareness of and access to safer conception strategies.

Late presentation to HIV/AIDS testing, treatment or continued care: clarifying the use of CD4 evaluation in the consensus definition.

OBJECTIVES: Late presentation to HIV/AIDS services compromises treatment outcomes and misses opportunities for biomedical and behavioural prevention. There has been significant heterogeneity in how the term 'late presentation' (LP) has been used in the literature. In 2011, a consensus definition was reached using CD4 counts to define and measure late presenters and, while it is useful for clinical care, the consensus definition has several important limitations that we discuss in this article. METHODS: Using the spectrum of engagement in HIV care presented by Gardner and colleagues, this article highlights issues and opportunities associated with use of the consensus definition. RESULTS: The consensus definition is limited by three principal factors: (1) the CD4 count threshold of 350 cells/µL is being increasingly questioned as the biomedical justification grows for earlier initiation of treatment; (2) CD4 evaluations are conducted at multiple services providing HIV care; thus it remains unclear to which service the patient is presenting late; and (3) the limited availability of CD4 evaluation restricts its use in determining the prevalence of LP in many settings. CONCLUSIONS: The consensus definition is useful because it describes the level of disease progression and allows for consistent evaluation of the prevalence and determinants of LP. Suggestions are provided for improving the application of the consensus definition in future research.

Unannounced telephone-based pill counts: a valid and feasible method for monitoring adherence.

Phone-based unannounced pill counts to measure medication adherence are much more practical and less expensive than home-based unannounced pill counts, but their validity has not been widely assessed. We examined the validity of phone versus home-based pill counts using a simplified protocol streamlined for studies embedded in clinical care settings. A total of 100 paired counts were used to compare concordance between unannounced phone and home-based pill counts using interclass correlations. Discrepancy analyses using χ(2) tests compared demographic and clinical characteristics across patients who were concordant between phone and home-based pill counts and patients who were not concordant. Concordance was high for phone-based and home-based unannounced total pill counts, as well as individual medication counts and calculated adherence. This study demonstrates that a simplified phone-based pill count protocol can be implemented among patients from a routine clinical care setting and is a feasible means of monitoring medication adherence.

Association between use of specific drugs and antiretroviral adherence: findings from MACH 14.

To determine the association between individual substances of abuse and antiretroviral adherence, analyses require a large sample assessed using electronic data monitoring (EDM). In this analysis, EDM data from 1,636 participants in 12 US adherence-focused studies were analyzed to determine the associations between recent use of various substances and adherence during the preceding 4 weeks. In bivariate analyses comparing adherence among patients who had used a specific substance to those who had not, adherence was significantly lower among those who had recently used cocaine, other stimulants or heroin but not among those who had used cannabis or alcohol. In multivariate analyses controlling for sociodemographics, amount of alcohol use and recent use of any alcohol, cocaine, other stimulants and heroin each was significantly negatively associated with adherence. The significant associations of cocaine, other stimulants, heroin, and alcohol use with adherence suggest that these are important substances to target with adherence-focused interventions.

The role of SNPs in the α-chain of the IL-7R gene in CD4+ T-cell recovery in HIV-infected African patients receiving suppressive cART.

We previously found an association between faster CD4+ T-cell recovery in HIV-infected patients receiving combination antiretroviral therapy (cART) and interleukin-7 receptor-α (IL-7Rα) haplotype-2 in a predominantly Caucasian cohort. This study aims to determine whether this association was also significant in Africans. Patients were recruited from the Uganda AIDS Rural Treatment Outcomes (UARTO) cohort (n=352). We used survival analysis and linear mixed modelling (LMM) to determine factors associated with CD4 T-cell recovery. Eight IL-7Rα single-nucleotide polymorphisms (SNPs) were genotyped in both Africans and Caucasians (n=57). Soluble (s)IL-7Rα levels were measured by ELISA. In UARTO, IL-7Rα haplotype-2 was associated with slower CD4 T-cell recovery following cART by using survival analysis (P=0.020) and no association was found with LMM (P=0.958). The tagging-SNP for IL-7Rα haplotype-2 (rs6897932) was associated with decreased sIL-7Rα (P<0.001). The haplotypes for the IL-7Rα were significantly different in Africans and Caucasians. Using IL-7Rα genotypes we found slower CD4 T-cell recovery in UARTO patients was still associated with rs6897932 (P=0.009) and rs3194051 was associated with faster CD4 T-cell recovery (P=0.006). Unlike Caucasians, we did not demonstrate a significant association between IL-7Rα haplotype 2 and faster CD4 T-cell recovery in Africans. The IL-7Rα SNPs associated with CD4 T-cell recovery following cART differ in African and Caucasian cohorts.

Reproductive counseling by clinic healthcare workers in Durban, South Africa: perspectives from HIV-infected men and women reporting serodiscordant partners.

BACKGROUND: Understanding HIV-infected patient experiences and perceptions of reproductive counseling in the health care context is critical to inform design of effective pharmaco-behavioral interventions that minimize periconception HIV risk and support HIV-affected couples to realize their fertility goals. METHODS: We conducted semistructured, in-depth interviews with 30 HIV-infected women (with pregnancy in prior year) and 20 HIV-infected men, all reporting serodiscordant partners and accessing care in Durban, South Africa. We investigated patient-reported experiences with safer conception counseling from health care workers (HCWs). Interview transcripts were reviewed and coded using content analysis for conceptual categories and emergent themes. RESULTS: The study findings indicate that HIV-infected patients recognize HCWs as a resource for periconception-related information and are receptive to speaking to a HCW prior to becoming pregnant, but seldom seek or receive conception advice in the clinic setting. HIV nondisclosure and unplanned pregnancy are important intervening factors. When advice is shared, patients reported receiving a range of information. Male participants showed particular interest in accessing safer conception information. CONCLUSIONS: HIV-infected men and women with serodiscordant partners are receptive to the idea of safer conception counseling. HCWs need to be supported to routinely initiate accurate safer conception counseling with HIV-infected patients of reproductive age.

Household water insecurity, missed schooling, and the mediating role of caregiver depression in rural Uganda.

BACKGROUND: School attendance rates in sub-Saharan Africa are among the lowest worldwide, placing children at heightened risk for poor educational and economic outcomes. One understudied risk factor for missed schooling is household water insecurity, which is linked to depression among women and may increase children's water-fetching burden at the expense of educational activities, particularly among children of depressed caregivers. In this study conducted in rural Uganda, we assessed the association between household water insecurity and child school participation and the mediating pathways behind these associations. METHOD: We conducted a population-based, cross-sectional study of female household heads (N = 257) and their children ages 5-17 (N = 551) in the rural regions surrounding the town of Mbarara, in southwestern Uganda. We used multivariable linear regressions to estimate the association between water insecurity and missed schooling. We then assessed the extent to which the association was mediated by caregiver depression. RESULTS: Among children, water insecurity had a statistically significant association with the number of missed school days (a standard deviation increase in water insecurity resulted in 0.30 more missed school days in the last week). The estimated association was partially mediated by caregiver depression. When stratified by sex, this mediating pathway remained significant for boys, but not among girls. CONCLUSIONS: Water insecurity is a risk factor for missed schooling among children in rural Uganda. Caregiver depression partially mediated this relationship. Also addressing caregiver mental health in water insecure families may more fully address the needs of sub-Saharan African families and promote educational participation among youth.

Case management is associated with improved antiretroviral adherence and CD4+ cell counts in homeless and marginally housed individuals with HIV infection.

BACKGROUND: Case management (CM) coordinates care for persons with complex health care needs. It is not known whether CM is effective at improving biological outcomes among homeless and marginally housed persons with human immunodeficiency virus (HIV) infection. Our goal was to determine whether CM is associated with reduced acute medical care use and improved biological outcomes in homeless and marginally housed persons with HIV infection. METHODS: We conducted a prospective observational cohort study in a probability-based community sample of HIV-infected homeless and marginally housed adults in San Francisco, California. The primary independent variable was CM, defined as none or rare (any CM in 25% but 75%). The dependent variables were 3 self-reported health service use measures (receipt of primary care, emergency department visits and hospitalizations, and antiretroviral therapy adherence) and 2 biological measures (increase in CD4(+) cell count of >or=50% and geometric mean HIV load of or=50% improvements in CD4(+) cell count. CM was not associated with geometric HIV load <400 copies/mL when antiretroviral therapy adherence was included in the model. Study limitations include a lack of randomization. CONCLUSION: CM may be a successful method to improve adherence to antiretroviral therapy and biological outcomes among HIV-infected homeless and marginally housed adults.

Re-inventing adherence: toward a patient-centered model of care for drug-resistant tuberculosis and HIV.

BACKGROUND: Despite renewed focus on molecular tuberculosis (TB) diagnostics and new antimycobacterial agents, treatment outcomes for patients co-infected with drug-resistant TB and human immunodeficiency virus (HIV) remain dismal, in part due to lack of focus on medication adherence as part of a patient-centered continuum of care. OBJECTIVE: To review current barriers to drug-resistant TB-HIV treatment and propose an alternative model to conventional approaches to treatment support. DISCUSSION: Current national TB control programs rely heavily on directly observed therapy (DOT) as the centerpiece of treatment delivery and adherence support. Medication adherence and care for drug-resistant TB-HIV could be improved by fully implementing team-based patient-centered care, empowering patients through counseling and support, maintaining a rights-based approach while acknowledging the responsibility of health care systems in providing comprehensive care, and prioritizing critical research gaps. CONCLUSION: It is time to re-invent our understanding of adherence in drug-resistant TB and HIV by focusing attention on the complex clinical, behavioral, social, and structural needs of affected patients and communities.

Adherence to HIV antiretroviral therapy in HIV+ Ugandan patients purchasing therapy.

Our objective was to determine the level of adherence and reasons for non-adherence to antiretroviral therapy (ART) among HIV-positive (HIV+) people on ART in a resource-limited setting. Patients receiving ART were recruited into the cross-sectional study from three treatment centres in Kampala, Uganda. The number of missed doses over the last three days was assessed by structured patient interviews and dichotomized at +/-95% adherence. Reasons for non-adherence were assessed with both structured patient interviews and unstructured qualitative interviews. Independent predictors of non-adherence were assessed with multivariate logistic regression. In all, 304 HIV-infected persons on ART were enrolled into the study. Factors associated with non-adherence were marital status (odds ratio (OR) = 2.93, 95% confidence interval (CI) 1.32-6.50) and low monthly income <50 US$ [OR = 2.77, 95% CI 1.64-4.67]. We concluded that levels of self-reported adherence in patients receiving ART in Kampala are comparable to levels in resource-rich settings with inability to purchase and secure a stable supply as a major barrier to adherence.

Adherence to protease inhibitors, HIV-1 viral load, and development of drug resistance in an indigent population.

OBJECTIVE: To examine the relationship between adherence, viral suppression and antiretroviral resistance in HIV-infected homeless and marginally housed people on protease inhibitor (PI) therapy. DESIGN AND SETTING: A cross-sectional analysis of subjects in an observational prospective cohort systematically sampled from free meal lines, homeless shelters and low-income, single-room occupancy (SRO) hotels. PARTICIPANTS: Thirty-four HIV-infected people with a median of 12 months of PI therapy. MAIN OUTCOMES: Adherence measured by periodic unannounced pill counts, electronic medication monitoring, and self-report; HIV RNA viral load; and HIV-1 genotypic changes associated with drug resistance. RESULTS: Median adherence was 89, 73, and 67% by self-report, pill count, and electronic medication monitor, respectively. Thirty-eight per cent of the population had over 90% adherence by pill count. Depending on the measure, adherence explained 36-65% of the variation in concurrent HIV RNA levels. The three adherence measures were closely related. Of 20 genotyped patients who received a new reverse transcriptase inhibitor (RTI) when starting a PI, three had primary protease gene substitutions. Of 12 genotyped patients who received a PI without a new RTI, six had primary protease gene substitutions (P < 0.03). CONCLUSION: A substantial proportion of homeless and marginally housed individuals had good adherence to PI therapy. A strong relationship was found between independent methods of measuring adherence and concurrent viral suppression. PI resistance was more closely related to the failure to change RTI when starting a PI than to the level of adherence.

In vivo gonadotropin-releasing hormone release and serum luteinizing hormone measurements in ovariectomized, estrogen-treated rhesus macaques.

The push-pull perfusion technique was used to measure GnRH release in unanesthetized female rhesus macaques (Macaca mulatta) and to examine the dynamic relationship between GnRH release and LH levels during the estrogen-induced LH surge. Each ovariectomized macaque was anesthetized and stereotaxically fitted with a push-pull cannula directed into the median eminence (ME). After at least 1 week of recovery, each animal received an estradiol benzoate (E2B) injection (42 micrograms/kg BW) or an oil (OIL) injection and underwent push-pull perfusion of the ME and blood sampling for at least 5 h between 28 and 56 h postinjection. Continuous 10-min push-pull perfusates were collected and prepared for GnRH RIA. Peripheral venous blood samples were obtained either hourly or every 10 min, and serum LH levels were determined by Leydig cell bioassay. GnRH release was detectable and pulsatile in areas in or adjacent to the ME or arcuate nucleus. In eight OIL monkeys, GnRH pulses were regular (approximately one pulse every 60 min) and of low amplitude (14.7 +/- 12.0 pg), with a mean GnRH release rate of 4.0 +/- 1.7 pg/10 min. In five E2B-treated monkeys, GnRH release during the rising phase of the LH surge occurred as an apparent burst of high amplitude GnRH pulses. The mean GnRH release rate (37.5 +/- 17.9 pg/10 min) and mean GnRH pulse amplitude (170.0 +/- 90.0 pg) during the 5 h before the peak LH level in E2B-treated monkeys were greater than OIL values (P less than 0.025, mean release; P less than 0.05, mean amplitude). Within individual E2B-treated monkeys, hourly mean GnRH release rates were significantly correlated with LH levels during the ascending limb of the LH surge (r = 0.75 +/- 0.11; P less than 0.025). We have concluded that an increase in GnRH neurosecretion occurs in E2B-treated monkeys and that it is associated with generation of the LH surge. On the basis of our observations, we hypothesize that the primate hypothalamus, through changes in GnRH secretion, actively participates in the E2B-induced LH surge.

Modeling the impact of modified directly observed antiretroviral therapy on HIV suppression and resistance, disease progression, and death.

A simulation model that used Markov assumptions with Monte Carlo uncertainty analysis was evaluated 1500 times at 10,000 iterations. Modified directly observed therapy (MDOT) for human immunodeficiency virus was assumed to improve adherence to therapy to 90% of prescribed doses. The impact of MDOT interventions on modeled biological and clinical outcomes was compared for populations with mean rates of adherence (i.e., the mean percentage of prescribed doses taken by each member of the population who had not discontinued therapy) of 40%, 50%, 60%, and 70%. MDOT reduced the risk of virological failure, development of opportunistic infections, and death, yet increased the risk of drug resistance, for each adherence distribution among persons with detectable plasma virus loads. Over 1500 trials, for a population with 50% adherence to therapy and a 12-month period, MDOT increased the median rate of virological suppression from 13.2% to 37.0% of patients, decreased the rate of opportunistic infection from 5.7% to 4.3% of patients, and decreased the death rate from 2.9% to 2.2% of patients. In the same population, however, MDOT increased the rate of new drug resistance mutations from 1.00 to 1.41 per person during the 12-month period. The impact of MDOT was smaller in populations with higher levels of adherence. MDOT interventions will likely improve clinical outcomes in populations with low levels of adherence but may not be effective at preventing drug resistance in treatment-experienced populations. MDOT may be more effective in preventing drug resistance with potent regimens in treatment-naive patients.

Reduction in tuberculin skin-test conversions among medical house staff associated with improved tuberculosis infection control practices.

OBJECTIVE: To assess the efficacy of an infection control program as measured by tuberculin skin-test (TST) conversion rates in medical house staff. DESIGN: Observational study. SETTING: University-based hospital in New York City serving a large indigent population. PARTICIPANTS: Medical house staff. INTERVENTIONS: TST conversions were measured every 6 months in medical house staff from June 1992 to June 1994. Compliance with the isolation policy was measured by identifying room locations 24 hours after admission of patients who had Mycobacterium tuberculosis recovered from respiratory specimens. RESULTS: The TST conversion rate decreased from 5.8 to 0, 2.3, and 0 per 100 person years of exposure in successive 6-month periods. The estimated annual TST conversion rate among interns fell from 7 per 100 person years in June 1992 to 0 per 100 person years in June 1993 and 0 per 100 person years in June 1994 (P < .029). The proportion of patients with pulmonary tuberculosis who were isolated in negative-pressure rooms increased from 38% to 75% over the study period (P < .01). CONCLUSION: Development of a multifaceted infection control program can decrease the risk of nosocomial tuberculosis infection in medical house staff.

A heterogeneous outbreak of Enterobacter cloacae and Serratia marcescens infections in a surgical intensive care unit.

OBJECTIVE: To investigate an outbreak of invasive disease due to Enterobacter cloacae and Serratia marcescens in a surgical intensive care unit (ICU). DESIGN: Pulsed-field gel electrophoresis (PFGE) analysis of restriction fragments was used to characterize the outbreak isolate genotypes. A retrospective cohort study of surgical ICU patients was conducted to identify risk factors associated with invasive disease. Unit staffing data were analyzed to compare staffing levels during the outbreak to those prior to and following the outbreak. SETTING: An urban hospital in San Francisco, California. PATIENTS: During the outbreak period, December 1997 through January 1998, there were 52 patients with a minimum ICU stay of > or = 72 hours. Of these, 10 patients fit our case definition of recovery of E. cloacae or S. marcescens from a sterile site. RESULTS: PFGE analysis revealed a highly heterogeneous population of isolates. Bivariate analysis of patient-related risk factors revealed duration of central lines, respiratory colonization, being a burn patient, and the use of gentamicin or nafcillin to be significantly associated with invasive disease. Both respiratory colonization and duration of central lines remained statistically significant in a multivariate analysis. Staffing data suggested a temporal correlation between understaffing and the outbreak period. CONCLUSIONS: Molecular epidemiological techniques provided a rapid means of ruling out a point source or significant cross-contamination as modes of transmission. In this setting, patient-related risk factors, such as respiratory colonization and duration of central lines, may provide a focus for heightened surveillance, infection control measures, and empirical therapy during outbreaks caused by common nosocomial pathogens. In addition, understaffing of nurses may have played a role in this outbreak, highlighting the importance of monitoring staffing levels.

Prevalence of antiretroviral drug resistance in the HIV-1-infected urban indigent population in San Francisco: a representative study.

We determined the prevalence of antiretroviral (ARV) resistance in HIV-1 infected indigent persons in San Francisco, California. Three hundred and twenty-seven subjects (159 (49%) ARV naïve, and 168 (51%) ARV-experienced), were recruited during 1996-97 and 1999-2000. Plasma HIV-1 viral load quantification and genotypic resistance testing were performed. Twice as many subjects received nucleoside reverse transcriptase inhibitors (NRTIs) as non-nucleoside reverse transcriptase inhibitors (NNRTIs) or protease inhibitors (PIs); resistance mutation prevalences were 30%, 14% and 16% respectively. Risk of any resistance mutations was strongly and independently associated with prior ARV exposure (OR = 1.3 per year of exposure, P < 0.0001) and with ARV exposure prior to HAART (OR = 2.5, P = 0.015). Prevalences of primary ARV resistance mutations among both treatment-naive and treatment-experienced subjects in this indigent urban population are low compared to other observational cohorts, are directly related to length and type of prior ARV exposure, and did not increase significantly between recruitment periods.