TB/HIV

Infection control programme has reduced TB incidence in Tugela Ferry hospital at centre of XDR-TB outbreak

By Lesley Odendal

The prevalence of culture-positive tuberculosis, and multidrug-resistant and extensively drug-resistant tuberculosis (MDR-TB and XDR-TB respectively) has decreased significantly between 2005 and 2008 at the Church of Scotland Hospital (COSH) in Tugela Ferry in KwaZulu-Natal, due to an improved infection control programme.

A point prevalence survey of the inpatient TB wards for one single day in both 2005 and 2008 showed that for the patients screened (n=25 and 35 respectively), the proportion of patients with culture-positive TB has decreased from 88% to 25.7%. The proportion with drug-resistant (DR) TB has also dropped dramatically from 64% in 2005 to only 8.6% in 2008.

These declines indicate that fewer patients are able to transmit TB to others in the facility.

The Infection Control Manager of the facility, Kathryn Catterick, presented the findings and methods of the Church of Scotland Hospital (COSH) at the Fourth South African AIDS Conference in South Africa. Simple and feasible measures that are already outlined in national policy were used and practices were monitored on an ongoing basis.

Church of Scotland Hospital was the first site to identify the presence of XDR-TB in HIV-positive patients, when, in 2005 it detected an alarmingly high death rate among patients previously doing well on antiretroviral therapy.

Investigation subsequently detected 53 cases at the hospital during the first year, growing to 266 by mid-2007.

COSH is a rural 40 to 50-bed district hospital with congregate wards serving a population of around 172,000 patients. The annual TB incidence is 1054 per 100,000 and the annual incidence for MDR-TB is 141 per 100,000. Since 2005, 820 confirmed drug-resistant TB cases have been seen at the facility, 43% of which were MDR-TB and 57% XDR-TB.

Nosocomial transmission of TB (that which takes place in a healthcare setting and is secondary to the condition originally being treated) is a documented problem in this facility. In COSH in 2005, it was found that, of the 53 cases of XDR-TB, 85% of the isolates had similar genetic fingerprint by spoligotype, 55% had not previously received TB treatment and 67% had been hospitalised in the last two years.. These findings indicate that most patients acquired XDR-TB from others in the hospital.

Since 2005, 13 healthcare workers have been diagnosed with drug-resistant TB and nine have since died. Nosocomial transmission due to poor infection control practices in South Africa is also evidenced in the fact that for 2006, 2442 more cases in absolute numbers of all MDR-TB patients occured in people diagnosed with TB for the first time and not in re-treatment cases.

A synergistic and multifaceted approach was used in the infection control programme including the appointment of an infection control officer and cough officers. Cough officers screened every patient entering ambulatory care on five days of the week.

In the outpatient clinic it was found that 10.8% of those screened were AFB smear-positive. In the Gateway clinic, 6.5% were smear-positive and 9% in the ARV clinic. However, culture testing showed that 20% of patients screened in the ARV clinic were culture-positive, including DR-TB cases, indicating a high prevalence of smear-negative TB.

Attempts to reduce patients' length of stay were also made. However it was found that, although the number of admissions was decreasing, the length of stay was not significantly different.

Natural ventilation is emphasised in COSH. In 2006 extractor fans were installed and an open-window policy was instituted. Unannounced audits were conducted to monitor the opening of windows. In the male ward, this improved from 78% of the time to 93%. In the female ward, improvements was observed from 68% to 82%. To reduce risk of transmission, the DOT office and the ARV clinic were moved to the periphery of the hospital.

In 2007, a staff survey regarding understanding and knowledge of mask and respirator use was conducted, followed by mask education on the use of N95 respirators. Fit testing and fit checks were regularly conducted. In unannounced audits, it was found that respirator use amongst staff was consistently as high as 95%.

Staff are also screened for TB regularly and voluntary testing and counselling and testing for HIV are promoted. Staff are discreetly moved to lower risk areas if they are HIV-positive.

The proportionate decrease in the number of TB cases being diagnosed in COSH is assumed to be due to the improved infection control programme. The approach must be multifaceted and continuously monitored. Through utilising existing resources, strategies that are feasible, practical and measurable can be implemented in rural facilities to prevent nosocomial TB transmission. However, Kathryn Catterick emphasised that infection control measures in communities are being neglected.

Reference
Catterick K et al. Feasible and effective infection control programme to limit nosocomial transmission of drug-resistant TB in Tugela Ferry. Fourth South African AIDS Conference, Durban, abstract 455, 2009.

Integrated screening tool improves TB screening rate in HIV patients in Eastern Cape

By Lesley Odendal

Integrating a TB screening tool into the adult clinical record (ACR) in HIV treatment facilities in South Africa’s Eastern Cape has resulted in a significant increase in the number of HIV-positive people diagnosed with TB, say researchers from the International Centre for AIDS Care and Treatment Programs (ICAP).

Screening for TB is critical in HIV-positive people, given the increased risk of infection and differences in clinical presentation.

Researchers Sabine Verkuijl and Jeanette Wessels from ICAP piloted the integration of TB screening into the adult clinical record in public health facilities in three subdistricts in the Eastern Cape.

The first step in completing the adult clinical record involves assessing if the patient enrolled into HIV or ARV care is symptomatic for TB, using a screening questionnaire.

Those patients who screen positive, meaning that they have one or more of six listed symptoms or signs, are then further investigated to confirm active TB. This includes investigations for pulmonary TB (sputum smears and/or culture, chest X-ray) and for extra-pulmonary TB (lymph-node aspirates, pleural taps, abdominal ultrasound and other measures). If active TB is confirmed, TB treatment is started and these patients also receive cotrimoxazole prophylactic treatment.

Overall, the percentage of ARV patients who were screened for TB increased from 73.2 % to 95% between 2007 and 2008.

Of those screened, the percentage of patients with a positive symptom screen remained approximately the same: around 49% in both 2007 and 2008.

Out of those with a positive screen, the percentage of patients diagnosed with TB dropped from 40.6% to 23.8%.

The data collected from the ACR allows for comparison of TB screening practices across regions and between facilities. In the ICAP-supported districts, clear differences can be seen in the extent to which TB screening is routinely done. In Nelson Mandela Bay almost all patients are routinely screened at enrolment into HIV care. In Buffalo City LSA (East London), only 35% of patients are screened, and less than 60% of those with a positive screen are investigated for TB.

The availability of these data allows for increased monitoring of the extent of TB screening for people in HIV care.

The proportion of HIV-positive people being screened for TB in South Africa is exceptionally low, with an average of only 40% in 2007. For the Eastern Cape Department of Health, this is significantly lower at 27% in 2007.

The main advantages of the integrated screening tool in the clinical record are the quality and continuity of care it allows. It reminds clinicians to screen for active TB at each and every visit for patients enrolled in HIV care and on antiretroviral treatment (ART).

It also prevents unmasking of TB through immune reconstitution inflammatory syndrome (IRIS) in patients with lower CD4 counts.

The ruling out of TB through the ACR is also crucial for the correct implementation of isoniazid preventive therapy (IPT).

The ACR also allows the clinician to monitor TB investigation results, TB treatment progress and TB treatment outcome. Essentially, the ACR improves practical integration between the HIV and TB programme.

In order to get feedback from users in the facilities, an eight-question questionnaire was administered in facilities in the Nelson Mandela Bay Municipality. Respondents were asked to indicate on a scale from 1 to 5 whether or not they agreed with different statements regarding the ease of use of the ACR and the perceived impact on the quality of care. Feedback was generally very positive, with scores between 4.6 and 5.

The operating characteristics of the TB screening questionnaire, including the sensitivity and specificity of the symptoms and signs included, will be evaluated in a public health evaluation in two ICAP-supported facilities.

Reference
Wessels J et al. Integration of a TB screening tool into a comprehensive HIV adult clinical record in the Eastern Cape, South Africa. Fourth South African AIDS Conference, Durban, abstract 485, 2009.

Smear-negative TB: C-reactive protein may provide useful screening method

By Lesley Odendal

Screening HIV-positive people with smear-negative pulmonary TB for high levels of C-reactive protein (CRP) can detect the presence of active TB with a fairly high degree of accuracy, suggesting that C-reactive protein could provide the basis for a point-of-care test to detect active TB in smear-negative cases in high-burden settings, according to findings from a study presented at the Fourth South African AIDS Conference in Durban in early April.

Smear microscopy is the first line of diagnosis in people with suspected TB. Sputum is added to a slide, stained with a dye that shows up TB bacilli and then viewed under a microscope to determine if TB bacilli are present.

However, in people with HIV, pulmonary infection with TB is more likely to produce a smear-negative result, resulting in delayed treatment while further diagnostic tests are carried out, or – in some cases – a complete failure to treat active TB.

Both lead to increased mortality in HIV-positive people.

A simple point-of-care diagnostic test to overcome these problems is urgently needed.

C-reactive protein, a marker of inflammation that is easily measured in a blood sample, is elevated in untreated smear-negative pulmonary TB.

Previous studies in HIV-negative patients suggest that C-reactive protein is more likely to be elevated where more serious tissue damage has occurred in the lungs as a result of TB.

In order to investigate the relationship between CRP levels and the presence of active TB in smear-negative individuals with suspected pulmonary tuberculosis, Douglas Wilson from the University of KwaZulu-Natal and colleagues conducted a sub-group analysis on a prospective cohort of people with suspected smear-negative tuberculosis, recruited from primary health care clinics in the Edendale Hospital catchment area between 2005 and 2007.

For each patient recruited into the study, mycobacterial culture was performed on induced sputum and other clinically relevant material. The two groups were divided into those with confirmed pulmonary TB and those who had pulmonary TB excluded.

Inclusion criteria for both groups were that individuals had to be HIV-positive or have clinical evidence of HIV infection, have been coughing for more than two weeks and have two AFB-negative sputum smears, as well as having been evaluated by a primary health care clinician, including with a chest X-ray.

For the confirmed pulmonary TB group, laboratory evidence of TB through culture testing was necessary and patients would be initiated on TB treatment. For the pulmonary TB-excluded group, all laboratory evidence would have to confirm the exclusion of pulmonary TB.

Of the 504 people with suspected TB who were screened, 421 were enrolled into the cohort. Of these:

• 105 patients (24.9%) were confirmed with smear-negative pulmonary TB

• 102 patients were confirmed culture-positive

• two patients tested AFB smear-positive

• one patient was lymph-node histology positive for TB

• 46 patients (10.9%) were diagnosed with smear-negative pulmonary TB

• 67 patients (63.8%) received an oral antibiotic.

Children in rural South Africa may be at increased risk of acquiring MDR-TB in hospitals